Thesis (D. Min.)--Harding University Graduate School of Religion, 2001. / Includes bibliographical references (leaves 261-285).

Thesis (M.A.)--Mississippi State University. Department of English. / Title from title screen. Includes bibliographical references.

Thesis (Ph.D.)--Baylor University, 2006. / Includes bibliographical references (p. 341-348).

El presente Trabajo de Título tuvo por objetivo diseñar y construir un modelo físico a escala del lecho empacado que utilizará la futura planta piloto de conversión continua de cobre, perteneciente al proyecto Fondef D04I1307 “Nuevo proceso continuo de conversión de mata a cobre Blister” destinada a procesar 5 (ton/h) de mata de cobre líquida. Con el modelo físico se pretendió simular las condiciones fluidodinámicas de operación de la planta (sin considerar transferencia de masa ni de calor), buscando obtener relaciones entre los parámetros de operación y la respuesta fluidodinámica del lecho, midiendo datos de caída de presión y de retención dinámica de líquido de la columna (holdup dinámico). La escala de construcción del modelo físico corresponde a 1:10 con respecto a la planta piloto, y se diseñó bajo el concepto de similitud geométrica. Se evaluó el comportamiento del lecho para diferentes diámetros de relleno, utilizando esferas de vidrio de 5, 10 y 15 (mm) de diámetro, estudiando también el comportamiento de trozos de ladrillo refractario clasificados como relleno. La mata de cobre se simuló con agua y el aire enriquecido con cilindros de aire industrial. Bajo condiciones de lecho seco (sin flujo de agua en contracorriente al aire), se obtuvo curvas de flujo de aire v/s caída de presión, las cuales se adecuaron bastante bien a lo predicho teóricamente por la ecuación de Ergun, lo que indicó que el arreglo experimental y los instrumentos de medición operaban correctamente. Además se consiguió establecer que la ecuación es aplicable a la planta piloto. Para condiciones de flujo de agua y aire en contracorriente se pudo concluir que un menor diámetro de partícula otorga mayor holdup dinámico, y por lo tanto mayor tiempo de residencia, además de provocar una mayor caída de presión. Por otro lado, un diámetro grande de partícula genera una baja caída de presión, acompañada de menores tiempos de residencia y un menor aprovechamiento de la superficie sólida disponible para contactar las fases de líquido y gas. Los ladrillos refractarios permitieron, en un comienzo, bajos niveles de holdup dinámico, para posteriormente dar paso a la aparición súbita de la condición de inundación (condición de operación máxima de la columna empacada). Esto se asocia a la diferencia en la interacción del agua con la superficie del ladrillo refractario y a la desigualdad entre la geometría esférica y la geometría irregular de los ladrillos. En todos los arreglos se alcanzó en algún punto la condición de inundación (flooding), esto permitió determinar el límite máximo de operación para la columna con diferentes rellenos. Finalmente se intentó escalar los resultados a los esperables para la planta piloto, no obstante, la diferencia entre los números adimensionales pertinentes al modelo físico y al prototipo (planta piloto) indicó una imposibilidad de confiar en los resultados de un eventual escalamiento. Esta restricción no impidió realizar una estimación para determinar si se dará o no la condición de flooding bajo los parámetros de operación de la columna piloto. De acuerdo a los resultados de esta aproximación se concluyó que la columna operará lejos su condición de capacidad máxima.

No description available.

No description available.

Nous avons étudié l'effet d'une réaction chimique sur le transfert de matière pour des systèmes à deux phases sous écoulement. La phase continue est une phase fluide et la phase dispersée est constituée de particules de catalyseur au sein desquelles une réaction chimique irréversible de premier ordre a lieu. Le soluté réactif est transporté par l'écoulement externe de fluide et pénètre dans la particule par diffusion, il se produit alors une réaction chimique qui consomme cette espèce. Nous modélisons le problème par un couplage interne-externe des équations de bilan et au moyen de deux conditions limites de raccordement: continuité de la concentration et équilibre des flux de masse à la surface des particules. Le cas d'une seule sphère isolée est traitée en premier lieu de manière théorique et numérique. Nous proposons un modèle pour prédire le coefficient de transfert de masse (nombre de Sherwood «réactif») en tenant compte de la convection-diffusion externes et du couplage diffusion-réaction internes. Nous validons le modèle en le comparant à des simulations numériques directes pleinement résolues (DNS boundaryfitted) sur un maillage adapté à la géométrie des particules. Pour la simulation de systèmes multiparticules, nous mettons en œuvre une méthode d'interface «Sharp» pour traiter les fronts raides de concentration. Nous validons la mise en œuvre de la méthode sur des solutions analytiques existantes en cas de diffusion, de diffusion-réaction et par comparaison avec des corrélations de convection-diffusion disponibles dans la littérature. Dans le cas d'une réaction chimique en présence de convection-diffusion, nous validons la méthode et nous évaluons sa précision en comparant avec les simulations pleinement résolues de référence. Ensuite, nous étudions le problème de l'écoulement et du transfert autour de trois sphères alignées soumis à une réaction chimique interne. Nous proposons un modèle de nombre de Sherwood «réactif» en complément d'une prédiction de transfert pour chaque sphère disponible dans la littérature. Nous validons le modèle par comparaison avec des simulations numériques directes pour une large gamme de paramètres adimensionels. Ensuite, nous étudions la configuration du lit fixe de particules de catalyseur. Nous modélisons le profil de concentration moyenne, en tenant compte de la réaction chimique dans le lit et les profils de concentration moyenne surfacique et volumique des particules. Nous introduisons un modèle pour le nombre de Sherwood «réactif» qui est comparé à des simulations numériques pour en évaluer les limites de validité / We studied the effect of a first order irreversible chemical reaction on mass transfer for two-phase flow systems in which the continuous phase is a fluid and the dispersed phase consists in catalystspherical particles. The reactive solute is transported by the fluid flow and penetrates through the particle surface by diffusion. The chemical reaction takes place within the bulk of the particle. Wehandle the problem by coupling mass balance equations for internal-external transfer with two boundary conditions: continuity of concentration and mass flux at the particle surface. We start with the case of a single isolated sphere. We propose a model to predict mass transfer coefficient (`reactive' Sherwood number) accounting for the external convection-diffusion along with internal diffusion-reaction. We validate the model through comparison with fully resolved Direct Numerical Simulations (DNS) performed by means of a boundary-fitted mesh method. For the simulation of multi-particle systems, we implemented a Sharp Interface Method to handle strong concentration gradients. We validate the implementation of the method thoroughly thanks to comparison with existing analytical solutions in case of diffusion, diffusion-reaction and by comparison with previously established correlations for convection-diffusion mass transfer. In case of convectiondiffusion- reaction, we validate the method and we evaluate its accuracy through comparisons with single particle simulations based on the boundary-fitted method. Later, we study the problem of three aligned-interacting spheres with internal chemical reaction. We propose a `reactive' Sherwood number model based on a known non-reactive prediction of mass transfer for each sphere. We validate the model by comparison with direct numerical simulations for a wide range of dimensionless parameters. Then, we study the configuration of a fixed bed of catalyst particles. We model the cup-mixing concentration profile, accounting for chemical reaction within the bed, and the mean surface and volume concentration profiles of the particles. We introduce a model for `reactive' Sherwood number that accounts for the solid volume fraction, in addition to the aforementioned effects. We compare the model to numerical simulations to evaluate its limitations

Essa tese analisa a obra literária dos escritores Sherwood Anderson (1876-1941) e Jack London (1876-1916) produzida nos anos 1900-1910, procurando compreender a maneira como se deu o diálogo entre a ficção e a realidade histórica, como aquela produziu uma leitura e uma interpretação desta, sobretudo no que tange às mudanças no sentido histórico do trabalho. Dado o fato de que ambos os escritores em questão viveram num momento decisivo de transformação histórica nos Estados Unidos, quando na transição entre o século XIX e XX se estabeleceram novas dinâmicas sociais e econômicas, articuladas estas com a consolidação do capitalismo de regime monopolista, essas literaturas trazem em seu corpo as cicatrizes históricas dos esforços de adaptação e compreensão desse processo. Atrelada a essa momentosa transição em curso, havia o fato de que ambos os escritores eram trabalhadores, e num momento crucial da formação da classe trabalhadora estadunidense, quando as transformações materiais impunham severas readequações na divisão do trabalho, na organização produtiva estrutural, na estratificação social dele oriunda, nas respostas políticas de resistência deles, e também nos sentidos subjetivos que o trabalho e o trabalhar poderiam possuir. Por conta de tudo isto, a literatura de Sherwood Anderson e Jack London produz uma interpretação ficcional dessa experiência histórica, permitindo com que se rastreie e compreenda como as velhas tradições do \"Evangelho do trabalho\" dos Oitocentos foram sendo brutalmente modificadas pela dinâmica produtiva de ordem fabril, pelo controle financeiro, pela concentração econômica e pela acentuação da exploração capitalista pelo regime monopólico. Essa situação, dadas as particularidades biográficas e os históricos de formação das regiões onde viveram os dois escritores (um do Meio-Oeste, outro do Extremo Oeste dos Estados Unidos), foi traduzida ora como crise de consciência íntima, ora como uma grande crise civilizacional que a punha em pé de igualdade com a selvageria da natureza. Ambas, pois, fornecem ao historiador chaves analíticas com as quais pensar a mudança do lugar e do sentido histórico do trabalho naquele processo, e como essa mudança participava da formação da classe trabalhadora, tanto em sentidos estruturais quanto subjetivos, tanto progressistas como conservadores. / This thesis analyzes the literary work of writers Sherwood Anderson (1876-1941) and Jack London (1876-1916) produced in the years 1900-1910, aiming at understanding the way how the dialogue between fiction and historical reality happened, how the former produced a reading and interpretation of the latter, especially regarding to shifts in the historical meaning of labor. Given the fact that both writers concerned lived in a decisive moment of historical transformation in the United States, when in the transition between the 19th and the 20th century new social and economical dynamics were established, articulated with the consolidation of the capitalism of monopolist regime, these writings bring in their body the historical scars of the efforts of adaptation and comprehension of this process. Attached to this momentous ongoing transition, there was the fact that both writers were workers, and during a crucial moment of the formation of the US working class, when the material transformations imposed severe readjustments in the division of labor, in the structural productive organization, in the social stratification originated from it, in the political answers of resistance from them, and also in the subjective senses that labor and work could have. Due to all that, the literature of Sherwood Anderson and Jack London produces a fictional interpretation of this historical experience, allowing to track and understand how the old traditions of the Gospel of work of the Eighteen hundreds were being brutally modified by the productive dynamics of the manufacturing industry, by the financial control, by the economic concentration and by the intensification of the capitalist exploration by the monopolistic regime. This situation, given the biographic particularities and the historical formation of the regions where the two writers lived (one from the Midwest, the other from the Far West of the United States), has been translated sometimes as a crisis of intimate consciousness, sometimes as a big civilizational crisis that put it on an equal footing with the wildness of nature. Both, therefore, provide the historian with analytical keys with which to think the shift of place and historical sense of labor in that process, and how this shift participated in the formation of the working class, both in structural and subjective senses, both progressives and conservatives.

Thesis (Ph.D.)--Bowling Green State University, 2008. / Document formatted into pages; contains viii, 256 p. : ill. Includes bibliographical references.

Thesis submitted in fulfilment of the requirements for the degree Doctor technologiae (engineering: chemical) In the faculty of engineering at the cape peninsula university of technology / Since the first uses of hollow-fiber membrane bioreactors (MBR’s) to immobilize whole cells were reported in the early 1970’s, this technology has been used in as wide ranging applications as enzyme production to bone tissue engineering. The potential of these devices in industrial applications is often diminished by the large diffusional resistances of the membranes. Currently, there are no analytical studies on the performance of the MBR which account for both convective and diffusive transport. The purpose of this study was to quantify the efficiency of a biocatalytic membrane reactor used for the production of enzymes. This was done by developing exact solutions of the concentration and velocity profiles in the different regions of the membrane bioreactor (MBR). The emphasis of this study was on the influence of radial convective flows, which have generally been neglected in previous analytical studies. The efficiency of the MBR was measured by means of the effectiveness factor. An analytical model for substrate concentration profiles in the lumen of the MBR was developed. The model was based on the solution of the Navier-Stokes equations and Darcy’s law for velocity profiles, and the convective-diffusion equation for the solute concentration profiles. The model allowed for the evaluation of the influence of both hydrodynamic and mass transfer operating parameters on the performance of the MBR. These parameters include the fraction retentate, the transmembrane pressure, the membrane hydraulic permeability, the Reynolds number, the axial and radial Peclet numbers, and the dimensions of the MBR. The significant findings on the hydrodynamic studies were on the influence of the fraction retentate. In the dead-end mode it was found that there was increased radial convective flow, and hence more solute contact with the enzymes/biofilm immobilised on the surface of the membrane. The improved solute-biofilm contact however was only limited to the entrance half of the MBR. In the closed shell mode there was uniform distribution of solute, however, radial convective flows were significantly reduced. The developed model therefore allowed for the evaluation of an optimum fraction retentate value, where both the distribution of solutes and radial convective flows could be maximised.