No presente trabalho, dados de ampliacao de escala, de um processo de pre-tratamento alcalino em escala laboratorial (2L) para escala piloto (350L) foram avaliados. Os experimentos realizados previamente em escala laboratorial apontaram duas condições potenciais para a ampliacao de escala, a saber: Ensaio 5 (130°C, 30 min, 1,5% m/v NaOH, 0,15% m/m antraquinona) apresentando a maior conversao enzimatica da polpa obtida (64,5%) e Ensaio 7 (170°C, 1,5 % m/v NaOH, 30 min, 0,15% m/m antraquinona) com a maior solubilizacao de lignina (81,0 %). Os experimentos em escala piloto foram realizados nas condicoes apontadas, com e sem a adicao de antraquinona. A reprodutibilidade dos dados em escala piloto foi satisfatoria, considerando o sistema de aquecimento e agitacao mais eficientes do reator piloto em relacao ao reator usado no laboratorio. O uso da antraquinona diminuiu a solubilizacao de carboidratos durante o pretratamento (evitando 67% de solubilizacao quando comparado a reacao sem antraquinona, a 130°C), mas interferiu negativamente na etapa subsequente de hidrolise, principalmente na reacao a 170°C. Dentre as condicoes testadas, o ensaio 5Pil/AQ (130°C, 30 min, 1,5% NaOH e 0,15% m/m antraquinona) foi eleito como a melhor condicao de pre-tratamento, com maior rendimento em carboidratos apos a hidrolise enzimatica, sendo possivel obter (extrapolando os resultados) 290 kg de glicose e 98 kg de xilose a partir de uma tonelada de bagaco (base seca). Para a obtencao de etanol a partir desse hidrolisado, foram realizadas fermentacoes com tres diferentes leveduras - S. cerevisiae CAT-1, S. stipitis NRRL Y-7124 e S. passalidarum NRRL Y-27907. O melhor resultado foi apresentado para fermentacao em batelada alimentada aplicando reciclo de celulas utilizando a levedura S. passalidarum, produzindo 23,3 g/L de etanol (97 % do teorico) com produtividade de 0,90 g/L.h em 24 h de fermentacao no terceiro reciclo. O processo de pre-tratamento alcalino gera, alem da polpa rica em carboidratos, um hidrolisado rico em lignina. A lignina foi precipitada desse hidrolisado apos cada pre-tratamento realizado e caracterizada, apresentando poder calorifico entre 22,8 e 25,3 MJ/kg. / In this study, data scale up for an alkaline pretreatment process from lab to pilot scale was evaluated. Lab scale experiments indicated two potential conditions for the scale-up, namely: 130°C, 30 min, 1.5% w/v NaOH, 0.15% w/w anthraquinone , presenting the highest enzymatic conversion (64.5%); and 170°C, 30 min, 1.5% w/v NaOH, 0.15% w/w anthraquinone with the highest lignin solubilization (81.0 %). The experiments were performed on pilot scale under the aforementioned conditions, with and without anthraquinone. Data reproducibility on pilot scale was satisfactory considering the more efficient heating and stirring reactor system when compared to the reactor in lab scale. Anthraquinone decreases the solubilization of carbohydrates during pretreatment (avoiding 67% solubilization compared to the reaction without anthraquinone, at 130°C), but interferes negatively in the subsequent hydrolysis step, mostely at 170°C. Among the conditions tested, the test performed at 130°C, 30 min, 1.5% w/v NaOH and with 0.15% w/w anthraquinone was chosen as the best pretreatment condition, with the highest carbohydrate conversion after enzymatic hydrolysis, allowing 290 kg of glucose and 98 kg of xylose per a dry base ton of bagasse. In order to produce ethanol from this hydrolyzate, fermentations with three different yeasts were performed - S. cerevisiae CAT-1, S. stipites NRRL Y-7124, S. passalidarum NRRL Y-27907. Fed-batch fermentation with S. passalidarum cell recycling provided the best result, yielding 23.3 g/L ethanol, 97 % (theoretical yield) with 0.90 g/L.h productivity within 24 h of fermentation. The alkaline pretreatment process generates, besides the pulp rich in carbohydrates, a lignin-rich hydrolyzate. Lignin was precipitated from the hydrolyzate obtained after each pretreatment carried out and characterized, presenting heating values between 22.8 and 25.3 MJ/kg.

It is estimated that over a third of the diet in the Western world is made up of oils and fats, of which a prominent percentage is in the form of emulsion food products, including milks, creams, yoghurts, margarines, salad dressings, desserts, soups and cheese. Current processing techniques involve the extraction and refining of edible oils using high temperatures and organic solvents, followed by re-encapsulation of the oil, for incorporation into the required emulsion products. The research presented in this PhD thesis was performed within the auspices of the UK Department of Environment, Food and Rural Affairs (DEFRA) funded, Sustainable Emulsion Ingredients through Bio-Innovation (SEIBI) project, which involved collaboration with researchers from the University of Nottingham together with a consortium of industrial partners. SEIBI was initiated to investigate a novel processing route for the production of food-grade rape and sunflowerseed oil emulsions from aqueously extracted oil-bodies. Being less energy and chemical intensive, the novel process offered potential reductions in both greenhouse gas emissions and wider environmental impacts when compared with conventional processing. Using Life Cycle Assessment (LCA) techniques, the environmental burdens of the aqueous oil-body extraction process were determined and compared with those of the existing technology route. To facilitate this, the research focussed on six key objectives, designed to both identify the environmental loads of the systems involved and scrutinise the impact of a number of methodological choices for LCA. These included choice of allocation method, normalisation, scaling issues distinct for novel processes and the extent to which the single-issue LCA variant, carbon footprinting could be used as an environmental indicator for the system. LCAs for four separate categories of product systems were developed encompassing seed oils, mayonnaises, aqueously extracted oil-body materials and mayonnaise-like oil-body emulsions. In addition to generating the environmental profiles required to fulfil the research objectives, the analysis of these models enabled the generation of original knowledge through the quantification of impacts for a range of processes that had either not previously been assessed or for which no published data could be found. The novel process was concluded as having clear potential for improved environmental performance over current technology even in its' pre-optimised, although the methodological choices examined were found to have profound effects on these and other results. Oil-body yield from seed was identified as key for optimisation to further maximise the environmental gains, with modest improvements, well within those theoretically possible being required for the novel process to better the environmental credentials of current technology in all key impact areas. The original outputs from this thesis will be of considerable use to developers involved in the continued advancement of the oil-body extraction technology, together with researchers within the edible oils and emulsions sector. In addition, the methodological outputs will help to inform LCA practitioners and developers in the continuing quest to understand the capabilities and limitations of this powerful analytical tool.

Este trabalho estudou a aplicação de oito métodos clássicos de escalonamento de tanques condicionadores, testando sua validade para dois tanques de geometria semelhante, mas com diferentes volumes (V1=10 e V2=49 decímetros cúbicos). No interior dos tanques, operavam impulsores (diâmetro D1=0,078m x D2=0,132m) que exibiam três distintos desenhos (2 pás versus 4 pás inclinadas em 45 graus versus turbina de Rushton). Sua rotação (N1 no tanque menor x N2 no tanque maior) visava à suspensão de partículas grossas de apatita (diâmetro médio = 254 micrometros) em polpas com 40% de sólidos em massa. Para balizar o escalonamento, adotou-se como variável de controle a mínima rotação do impulsor (Njs) que é capaz de fazer com que nenhuma partícula repouse no fundo do tanque por mais do que 1 ou 2 segundos (Critério 1-s), além de perfis axiais de distribuição de sólidos e a extensão da Zona Turbulenta versus Zona Quiescente no interior dos tanques. A diferença entre o valor previsto de Njs para o tanque de 49 decímetros cúbicos (N2) pelos métodos de escalonamento versus o valor de Njs (N2) determinado experimentalmente foi expressa como erro percentual (E). Consideraram-se como adequados para a aplicação que constitui o objetivo desta dissertação todos os métodos que exibiram E menor que 10%. Para o impelidor de 2 pás inclinadas, a adequação do método baseado na constância da razão potência/volume (E=2%) e também do método empírico de Rautzen (E=6%), indica a expressão N2=N1.(D1/D2) com seu expoente da relação entre os diâmetros variando entre 0,67 e 0,75 para a aplicação desejada. Considerando o impulsor de 4 pás inclinadas, a adequação do método da constância da razão potência/volume (E=4%); assim como dos métodos empíricos de Rautzen (E=0%) e Zwietering (5%), sugere o uso da expressão N2=N1.(D1/D2) com seu expoente da relação entre os diâmetros variando entre 0,67 e 0,85. Para a turbina de Rushton, o único método que exibiu E menor que 10% foi o da constância da relação potência/volume (E=8%), cuja expressão é N2=N1.(D1/D2) com seu expoente da relação entre os diâmetros igual a 0,67. Uma vez que a determinação do valor real de N2 foi baseada numa técnica experimental influenciada pelas limitações do observador, pode-se inferir que uma expressão geral de escalonamento do tipo N2=N1.(D1/D2) com seu expoente da relação entre os diâmetros igual a 0,75 atende aos propósitos desta aplicação. Por outro lado, o uso da relação P/V provê um critério mais objetivo para se balizar o escalonamento, haja vista que ele se adequou a todos os três tipos de impelidores contemplados por este estudo. / This work has studied the application of eight classical methods appointed by literature to accomplish the scale-up of stirred tanks which aimed to suspend slurries of 40% of solids, containing coarse (mean diameter=254 micrometers) apatite particles. The validity of the methods was accomplished by using two tanks of similar geometry but different capacity (V1=10 e V2=49 cubic decimeter), together with impellers of different diameter (D1=0,078m versus D2=0,132m) and design (turbine of 2 or 4 blades inclined at 45 degrees and Rushton turbine). To assist the process of validation, the impeller speed (Njs) under which no particle rests on the bottom of the tank for more than 1-2 seconds (1-s Criterium) was used together with the axial profile of solids percent distribution plus the extension of the turbulent versus quiescent zones within the two tanks. For any of the eight scale-up methods, the difference between the predicted value of Njs (N2) for the 49 cubic decimeter tank and the actual value (experimental) of the same variable was determined and its magnitude was expressed in terms of the percent error (E). The methods that yielded E less than 10% were considered as suitable for the aimed application. Considering the 2-inclined blade impeller, low value of E yielded by the method based on the constancy of the ratio power/volume (E=2%) and also by the empiric method of Rautzen (E=6%) indicate that the expression N2=N1.(D1/D2) with its exponent of the relation between diameters ranging between 0,67 and 0,75 is suitable for the desired application. Regarding the 4-inclined blade impeller, because the method based on the constancy of the ratio power/volume (E=4%) and also the empiric methods of Rautzen (E=0%) and Zwietering (E=5%) yielded the lowest values of E, the expression N2=N1.(D1/D2) with its exponent of the relation between diameters ranging between 0,67 and 0,85 is suitable for the aimed application. Moreover, for the Rusthon turbine, only the method based on the constancy of the ratio power/volume (E=8%) was adequate for the aimed application and, thus, the expression N2=N1.(D1/D2) with its exponent of the relation between the diameters equal to 0,67 is suitable for the purpose of this dissertation. Once the actual value of N2 is determined by visual observation, it is not possible to get very accurate results. This way, a generic scale-up expression is proposed: N2=N1.(D1/D2) with its exponent of the relation between the diameters equal to 0,75. On the other hand, the ratio P/V may provide a more objective criterium for scale-up, because the three sort of impellers used in this study yielded E less than 10% when the power/volume method was applied for the purpose of scale-up.

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No. of bitstreams: 1 perez_cl_me_sjrp.pdf: 6948213 bytes, checksum: 88316394d4ffc78684a65d0a022b2c93 (MD5) Previous issue date: 2017-03-03 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Esta dissertação apresenta um estudo sobre a ampliação de escala de biorreatores de leito empacotado para produção de celulases e hemicelulases por fermentação em estado sólido (FES) empregando o fungo termofílico Myceliophthora thermophila I-1D3b e substrato composto por bagaço de cana de açúcar e farelo de trigo. As etapas de desenvolvimento do projeto consistiram em ensaios em biorreator de diâmetro interno e altura iguais a 7,62 e 10 centímetros, de modo que foram realizados ensaios variando tamanho das partículas de bagaço de cana, densidade bulk do leito, taxas de aeração e modo de distribuição da vazão de ar. Com base nos resultados obtidos, observou-se que partículas de bagaço de tamanho reduzido fornecem bons rendimentos de atividades enzimáticas quando submetidas a altas taxas de aeração em leitos de elevada densidade. Partículas maiores forneceram melhores resultados para leitos de �bulk= 0,395 g/cm3 , bem como a utilização de vazão de ar determinada com base no número de Damköhler modificado igual a 1. Resultados obtidos em ensaios em biorreatores de 0,8 metros, com e sem distribuição de ar, mostraram que inserir ar ao longo do leito é uma estratégia que permite aeração eficiente ao longo do sistema fermentativo, sem que ocorra secagem excessiva do substrato. Atividades relativas de CMCase e xilanase atingiram cerca de 1,2 e 0,7, respectivamente. As etapas finais consistiram em fermentações realizadas em biorreator de diâmetro interno e altura iguais a 20 centímetros. Nessas condições, foram testadas duas formas de distribuição de ar ao longo do leito de quatro módulos fermentativos: utilizando um tubo interno perfurado no módulo central inserindo metade da vazão total, e a outra metade inserida pelo inferior do leito e utilizando um tubo interno central, com quatro orifícios por módulo para espalhamento da vazão. Em termos de produção de celulase, o tubo no módulo central se mostrou a melhor alternativa para o aumento de escala, chegando a apresentar 0,8 de atividades enzimáticas relativas de CMCase, e em termos de atividades relativas de xilanase, a melhor opção foi o tubo interno longitudinal, apresentando valores de 0,55. Diante do exposto, o número de Damköhler modificado é interessante do ponto de vista de aumento de escala, no entanto é preciso ainda entender o mecanismo de atividade respiratória dos microrganismos para que os conceitos possam ser aplicados em sinergia, podendo-se assim esperar bom desempenho do processo em escala industrial. / This work presents a study of scale–up packed bed bioreactors for the production of cellulases and hemicellulases by solid-state fermentation (SSF) using the thermophilic fungus Myceliophthora thermophila I-1D3b and substrate composed by sugar cane bagasse and wheat bran. The development phases of the project consist in tests using bioreactors composed by internal diameter and height equal to 7.62 and 10 centimeters, respectively, so that the assays vary the size of the sugar cane bagasse particles, the bulk density, the airflow rate and how’s distributed along the bed. Based on the results obtained, it was defined that the particles of small size provide good results of enzymatic activity yields when submitted to high aeration rates in high bulk density beds. When testing normal size sugarcane bagasse particles, the best results were obtained for the beds with �bulk= 0,395 g/cm3 as well as airflow rate based on the modified Damköhler number equal to 1. Results obtained in tests in 0,8 meter height bioreactors, with and without airflow distribution, show that inserting air in different bed heights is a strategy to ensure efficient aeration throughout the fermentation system without excessive drying of the substrate. Activities related to CMCase and xylanase reached about 1.2 and 0.7, respectively. The final stages consisted in perform fermentation assays in a bioreactor of internal diameter and height equal to 20 centimeters. Under these conditions, two forms of long-term distribution were tested: using an internal ring to insert half of the total flow, together with the other half inserted in the lower part of the bed and using a central internal pipe with 4 holes per module for airflow distribution. In terms of cellulase production, the internal ring showed a better alternative for scaling-up, reaching a valeu of 0.8 CMCase relative enzymatic activities, and with respect to xylanase relative enzymatic activities, the best option was the central pipe, presenting values of 0,55. On the above, the modified Damköhler number is interesting when it refers to scale-up, although it’s necessary to understand the mechanism of respiratory activity of the microorganisms so that the concepts can be applied in synergy, and it can be expected good process performance in industrial scale. / CNPq: 132957/2016-7

No presente trabalho, dados de ampliacao de escala, de um processo de pre-tratamento alcalino em escala laboratorial (2L) para escala piloto (350L) foram avaliados. Os experimentos realizados previamente em escala laboratorial apontaram duas condições potenciais para a ampliacao de escala, a saber: Ensaio 5 (130°C, 30 min, 1,5% m/v NaOH, 0,15% m/m antraquinona) apresentando a maior conversao enzimatica da polpa obtida (64,5%) e Ensaio 7 (170°C, 1,5 % m/v NaOH, 30 min, 0,15% m/m antraquinona) com a maior solubilizacao de lignina (81,0 %). Os experimentos em escala piloto foram realizados nas condicoes apontadas, com e sem a adicao de antraquinona. A reprodutibilidade dos dados em escala piloto foi satisfatoria, considerando o sistema de aquecimento e agitacao mais eficientes do reator piloto em relacao ao reator usado no laboratorio. O uso da antraquinona diminuiu a solubilizacao de carboidratos durante o pretratamento (evitando 67% de solubilizacao quando comparado a reacao sem antraquinona, a 130°C), mas interferiu negativamente na etapa subsequente de hidrolise, principalmente na reacao a 170°C. Dentre as condicoes testadas, o ensaio 5Pil/AQ (130°C, 30 min, 1,5% NaOH e 0,15% m/m antraquinona) foi eleito como a melhor condicao de pre-tratamento, com maior rendimento em carboidratos apos a hidrolise enzimatica, sendo possivel obter (extrapolando os resultados) 290 kg de glicose e 98 kg de xilose a partir de uma tonelada de bagaco (base seca). Para a obtencao de etanol a partir desse hidrolisado, foram realizadas fermentacoes com tres diferentes leveduras - S. cerevisiae CAT-1, S. stipitis NRRL Y-7124 e S. passalidarum NRRL Y-27907. O melhor resultado foi apresentado para fermentacao em batelada alimentada aplicando reciclo de celulas utilizando a levedura S. passalidarum, produzindo 23,3 g/L de etanol (97 % do teorico) com produtividade de 0,90 g/L.h em 24 h de fermentacao no terceiro reciclo. O processo de pre-tratamento alcalino gera, alem da polpa rica em carboidratos, um hidrolisado rico em lignina. A lignina foi precipitada desse hidrolisado apos cada pre-tratamento realizado e caracterizada, apresentando poder calorifico entre 22,8 e 25,3 MJ/kg. / In this study, data scale up for an alkaline pretreatment process from lab to pilot scale was evaluated. Lab scale experiments indicated two potential conditions for the scale-up, namely: 130°C, 30 min, 1.5% w/v NaOH, 0.15% w/w anthraquinone , presenting the highest enzymatic conversion (64.5%); and 170°C, 30 min, 1.5% w/v NaOH, 0.15% w/w anthraquinone with the highest lignin solubilization (81.0 %). The experiments were performed on pilot scale under the aforementioned conditions, with and without anthraquinone. Data reproducibility on pilot scale was satisfactory considering the more efficient heating and stirring reactor system when compared to the reactor in lab scale. Anthraquinone decreases the solubilization of carbohydrates during pretreatment (avoiding 67% solubilization compared to the reaction without anthraquinone, at 130°C), but interferes negatively in the subsequent hydrolysis step, mostely at 170°C. Among the conditions tested, the test performed at 130°C, 30 min, 1.5% w/v NaOH and with 0.15% w/w anthraquinone was chosen as the best pretreatment condition, with the highest carbohydrate conversion after enzymatic hydrolysis, allowing 290 kg of glucose and 98 kg of xylose per a dry base ton of bagasse. In order to produce ethanol from this hydrolyzate, fermentations with three different yeasts were performed - S. cerevisiae CAT-1, S. stipites NRRL Y-7124, S. passalidarum NRRL Y-27907. Fed-batch fermentation with S. passalidarum cell recycling provided the best result, yielding 23.3 g/L ethanol, 97 % (theoretical yield) with 0.90 g/L.h productivity within 24 h of fermentation. The alkaline pretreatment process generates, besides the pulp rich in carbohydrates, a lignin-rich hydrolyzate. Lignin was precipitated from the hydrolyzate obtained after each pretreatment carried out and characterized, presenting heating values between 22.8 and 25.3 MJ/kg.

De nos jours, les émulsions doubles se trouvent dans de nombreuses applications dans différents domaines, tels que le domaine alimentaire, les produits cosmétiques, les produits chimiques ou biochimiques. Dans les produits alimentaires par exemple, les émulsions doubles peuvent permettre d’encapsuler des arômes ou de réduire la teneur en matières grasses. La littérature manque cependant de compréhension globale de ces systèmes. La modélisation peut améliorer la compréhension d'un système et permettre d'optimiser les conditions de fonctionnement afin d'améliorer la qualité du produit. Dans ces systèmes, la qualité du produit est déterminée par l'efficacité de l'encapsulation et la distribution de la taille des gouttes internes et externes, qui peuvent affecter la stabilité physique pendant le stockage. L'objectif de ce travail est de réaliser une étude théorique et expérimentale approfondie des phénomènes intervenant à la fois lors de la préparation et du stockage des émulsions doubles. La contribution du travail peut donc être divisée en deux parties. Dans un premier temps, nous étudions les paramètres affectant l’étape de préparation des émulsions doubles et nous proposons des modèles pour les décrire. Trois procédés ont été considérés pour l’émulsification des émulsions doubles, l’ultra-sonication, l’Ultra-Turrax et un réacteur agité. Le modèle est basé sur un modèle de bilan de population des gouttelettes externes, incluant les phénomènes de rupture et de coalescence, associé à un modèle de relargage des gouttes internes. Le relargage des gouttes internes est supposé être régi par la rupture des gouttes externes. Pour être applicables aux différents procédés, les modèles de rupture ont été adaptés aux différentes échelles de turbulence, de dissipation pour ultra-sonication et inertielle pour Ultra-Turrax. La deuxième contribution de ce travail concerne l’étude des phénomènes ayant lieu lors du stockage des émulsions doubles, notamment le gonflement et le relargage des gouttes. Dans ce cas, deux modèles de bilan de population des gouttelettes internes et externes ont été développés, comprenant les phénomènes de gonflement des gouttelettes internes, et donc externes, ainsi que le relagage des gouttelettes internes par diffusion et coalescence avec la phase continue externe. Le modèle de gonflement prend en compte la pression de Laplace qui contrebalance le gradient de pression osmotique et arrête le gonflement. Dans les différentes étapes de préparation ou de stockage, les modèles développés permettent de prédire les distributions de la taille des gouttelettes et le taux de libération / Double emulsions can nowadays be found in a number of applications in different domains, like food, cosmetics, chemicals or biochemical. In food for instance, double emulsions may allow to encapsulate flavors or reduce the fat content. Yet, the literature is still lacking a comprehensive understanding of these systems. Modelling may improve the understanding of a system and allow optimizing the operating conditions in order to improve the product quality. In these systems, the product quality is determined by the encapsulation efficiency and the inner and outer droplet size distribution, which may affect the physical stability during storage. The objective of this work is to handle theoretical and experimental investigations of the phenomena occurring during both the preparation and the storage of double emulsions. The contribution of the work can therefore be divided into two parts. First of all, investigations of the parameters affecting the preparation step of double emulsions are handled, and models are proposed to describe them. Three processes were considered for the emulsification of the double emulsions, ultrasonication, Ultra-Turrax and a stirred vessel. The model is based on a population balance model of the outer droplets, including the kernels of breakage and coalescence combined with a leakage model of the inner droplets. The leakage of inner droplets is assumed to be governed by the breakage of the outer droplets. In order to be applicable in the different processes, the breakage models were adapted to different scales of turbulence, the dissipation subrange for ultrasonication and the inertial subrange for the Ultra-Turrax. The second contribution of the work concerns the investigation of the phenomena taking place during the storage of the double emulsions, including swelling and release. In this case, two population balance models of the inner and outer droplets were considered, including the phenomena of swelling of the inner, and so of the outer, droplets as well as the escape of the inner droplets by diffusion and coalescence with the external continuous phase. The swelling model takes into account the Laplace pressure that counterbalances the osmotic pressure which is the driving force for swelling. In the different steps of preparation or storage, the developed models allow the prediction of the droplet size distributions and the release rate

The nematode Caenorhabditis elegans is a model organism for understanding sensory molecules of multicellular organisms. Ovulating hermaphrodites produce putative pheromone(s) that cause male attraction. Because pheromones are produced in such small quantities, adult conditioned-media from large-scale synchronous culture is necessary to analyze these pheromones. Current protocols for culture synchronization have volume constraints that limit large-scale synchronous cultures and current methodology for adult conditioned-media production is impractical. Modification of Tangential Flow Filtration (TFF) systems was investigated for use as a method to increase the volume limits of bleach egg harvest for C. elegans culture synchronization. Also, an adult retention device built within the culture vessel was investigated to optimize the environment for aseptic conditioned-media production from dense large-scale C. elegans cultures. During this investigation, we have shown that synchronous C. elegans cultures for adult conditioned-media production can be grown at scales larger than reported before, with potential for further scale up. Our growth methodologies have also yielded denser cultures than previously achieved at large scales. Since rapid bleach harvesting appears to be the bottleneck for large-scale production of synchronous C. elegans cultures, our approach of using modified TFF systems with mesh to retain C. elegans eggs increased the amount of eggs that could be bleach harvested at one time. Using this method we have been able to achieve up to 5x103 synchronous C. elegans per mL at a 50L scale. Since scale-up of TFF is straightforward, our results suggest that the technique reported here can easily be applied to larger scale systems for production of adult conditioned-media for C. elegans. Further, the adult retention device within the culture vessel can ensure that the whole process remains aseptic.

The primary objectives of this study were: (1) to verify the effectiveness of ECAE to induce equal amounts of strain and grain refinement in bars of different cross-sectional areas, (2) to determine the effectiveness of ECAE in breaking down the as-cast macrostructure in CDA 101 Cu and in producing a homogeneous material containing micron-scale grains upon recrystallization, and (3) to determine a thermomechanical processing (TMP) schedule (from the ones examined) that produces the best microstructure in terms of grain size and uniformity. The effects of extrus ion route, levels of strain and intermediate heat treatment were investigated. To achieve the first objective, bars having square cross-sections of three different sizes, 19 mm, 25 mm and 50 mm, were processed up to eight ECAE passes through routes A, B, C and E. To achieve the second and third objectives, bars were processed up to eight ECAE passes with and without intermediate heat treatments through routes Bc, C, E and F. ECAE processing was carried out in a 90o extrusion die with sliding walls at an extrusion speed of 2.5 mm/s. Recrystallization studies were carried out on the processed material to evaluate the recrystallization behavior and thermal stability of the material. The as-worked and recrystallized materials were characterized by Vickers microhardness, optical microscopy (OM) and transmission electron microscopy (TEM). Results indicate that similar hardness values, sub-grain morphology and recrystallized grain size are generated in the three bars having different cross-sectional sizes processed through ECAE. ECAE is shown to induce uniform strain in all three billet sizes. ECAE is therefore shown to be effective in scale-up to a size of at least 50 mm, with larger billets giving better load efficiency. Results from the later parts of this study indicate that eight extrusion passes via route Bc produces the best microstructure in terms of grain size and microstructural uniformity. The routes can be arranged in the sequence Bc> E, F> C for their ability to produce a uniform recrystallized microstructure with small average grain size. Macroscopic shear bands are sometimes generated during extrusion depending upon the initial grain morphology and texture of the material.

Dispersion has been shown to degrade miscibility in miscible displacements by lowering the concentration of the injected solute at the displacement fronts. Dispersion can also improve oil recovery by increasing sweep efficiency. Either way, dispersion is an important factor in understanding miscible displacement performance. Conventionally, dispersion is measured in the laboratory by fitting the solution of one-dimensional convection-dispersion equation (CDE) to the effluent concentration from a core flood. However dispersion is anisotropic and mixing occurs in both longitudinal and transverse directions. This dissertation uses the analytical solution of the two-dimensional CDE to simultaneously determine longitudinal and transverse dispersion. The two-dimensional analytical solution for an instantaneous finite volume source is used to investigate anisotropic mixing in miscible displacements. We conclude that transverse mixing becomes significant with large a concentration gradient in the transverse direction and significant local variation in flow directions owing to heterogeneity. We also utilized simulation models similar to Blackwell's (1962) experiments to determine transverse dispersion. This model coupled with the analytical solution for two-dimensional CDE for continuous injection source is used to determine longitudinal and transverse dispersivity for the flow medium. The validated model is used to investigate the effect of heterogeneity and other first contact miscible (FCM) scaling groups on dispersion. We derive the dimensionless scaling groups that affect FCM displacements and determine their impact on dispersion. Experimental design is used to determine the impact and interactions of significant scaling groups and generate a response surface function for dispersion based on the scaling groups. The level of heterogeneity is found to most significantly impact longitudinal dispersion, while transverse dispersion is most significantly impacted by the dispersion number. Finally, a mathematical procedure is developed to use the estimated dispersivities to determine a-priori the maximum grid-block size to maintain an equivalent level of dispersion between fine-scale and upscaled coarse models. Non-uniform coarsening schemes is recommended and validated for reservoir models with sets of different permeability distributions. Comparable sweep and recovery are observed when the procedure was extended to multi-contact miscible (MCM) displacements. / text

Metal-organic frameworks (MOFs) are a relatively new class of porous materials, assembled from inorganic metal nodes and organic ligands. MOFs have garnered significant attention in the porous materials and adsorption fields in recent years due to their various attractive features such as high surface areas and pore volumes, tunable and uniform pore sizes, chemically functionalized adsorption sites, and potential for post-synthetic modification. These features give MOFs enormous potential for use in applications such as air purification, methane and hydrogen storage, separations, catalysis, sensing, and drug delivery. Therefore, synthesis and adsorption studies of MOFs have increased tremendously in recent years. Among the aforesaid applications, air purification and air quality control are important topics because existing porous media are ineffective at the adsorptive removal of toxic industrial chemicals (TICs) and chemical warfare agents. Thus, there is a critical need for radical improvements in these purification systems. MOFs have shown great potential to become next-generation filter media as they outperform the traditional porous materials such as activated carbons and zeolites in the air purification of TICs such as ammonia and sulfur dioxide. In spite of the numerous desirable attributes of MOFs, the practical use of these new materials in most applications hinges on their stability in humid or aqueous environments. The sensitivity of certain MOFs under humid conditions is well known, but systematic studies of the water stability properties of MOFs are lacking. This information is critical for identifying structural factors that are important for development of next-generation, water stable MOFs. In addition to the water stability issue, difficulty in the scale up of MOF synthesis has also plagued MOFs. Hence, the goal of this Ph.D. dissertation research is to design ammonia-selective, water stable MOFs that can be synthesized on a large scale. This work will have a direct impact on moving the MOF field forward to the commercial level. To achieve the aforementioned goal, this Ph.D. dissertation research has been divided into following three objectives: (1) Advance our understanding of the water stability of MOFs and develop design criteria for the construction of water stable MOFs. (2) Design water stable, ammonia-selective MOFs for next-generation chemical, biological, radiological, and nuclear (CBRN) filter media. (3) Investigate the scale-up of the UiO-66 MOF scaffold. Through the research efforts over the past four years, it is discovered that it is possible to adjust the water stability of pillared MOFs in both positive and negative directions by proper shielding of the ligand via functional groups. This study is the first of its kind and is of high value for the MOF community. This shielding concept is further extended by synthesizing 4 novel isostructural MOFs with methyl functional groups at different positions on the ligand. For the first time, light is shed on the important distinction between kinetic and thermodynamic water stability and experimental evidence for a kinetically governed water stability mechanism in these MOFs is provided. It is also demonstrated that, using catenation in combination with a pillaring strategy, it is possible to obtain water stable MOFs even when the pillar ligand has lower basicity (pKa value). Ammonia breakthrough measurements have shown that a hydroxyl functionalized Zr-based UiO-66 material is promising as it could offer a method for targeting the removal of specific chemical threats in a chemically stable framework that does not degrade in the presence of water. Large scale synthesis of a water stable MOF, UiO-66, is studied using glass vials and Teflon lined autoclaves. UiO-66 synthesis methods have been refined such that it is now possible to produce more than 70 times the yield obtained from the original synthesis report using the same reaction volume. This would result in a significant reduction of the MOF production cost at the industrial scale. Methane and hydrogen are ‘clean fuels’ (less CO2 emissions than petroleum) and MOFs are being tested for their on-board storage in cars due to the extremely high storage capacities of MOFs being promising enough to meet the requirements. Hence, more broadly, this Ph.D. dissertation work will lead to commercial applications of MOFs, which can revolutionize a variety of gas separation and storage problems such as CO2 capture, natural gas upgrading, and methane and hydrogen storage for clean fuel technologies. This would greatly reduce the environmental concerns faced by our society today.