The study aims to identify the strategies and the organization of the wheat flour industries and nutritious pastes of Rio Grande do Sul. It is used as theoretical base in the analysis, the production chain, the model structure-conduct-performance (SCP) and Porter s (1980) and Mintzberg s (1988) competitive strategies. In order to accomplish the research the descriptive method was used, with primary (structured questionnaire applied to the companies) and secondary data. The option of restricting the study to Rio Grande do Sul, was due to the fact that the state to be one of the pioneers and now one of the largest producers of wheat flour and nutritious pastes in the country. The results show that the wheat flour industries and of nutritious pastes are located close to one another in the state most them are of medium and small-size companies. It was also observed that both Brazil and Rio Grande do Sul are not self-sufficient in the wheat production thus, making the importation necessary. The main destination to products is the state itself, but the vertical integration in the productive chain is still low. It was also verified that the concentration of the industries falls from 2001 to 2006 and that there are barriers to the important entrance for the incoming in the wheat flour sector, as the minimum scale of production, and the capacity already installed of the companies producing nutritious pastes. Concerning Porter s competitive strategies, the production with lower costs is the most outstanding among the companies producing wheat flour, however, among the nutritious pastes it is the differentiation. Among the Mintzberg s typologies, the quality of the product is considered, by both industries, as being the big competitive differential. The performance of the industries in the analyzed period worsened, because there was profitability decrease and market share loss. / O estudo em questão visa identificar as estratégias e a organização das indústrias de farinha de trigo e de massas alimentícias do Rio Grande do Sul. Utiliza-se como base teórica na análise, a cadeia de produção agroindustrial, o modelo estruturaconduta-desempenho (ECD) e as estratégias competitivas de Porter (1980) e de Mintzberg (1988). Para realização da pesquisa, utilizou-se do método descritivo, com dados primários (questionário estruturado aplicado às empresas) e secundários. A opção de restringir o estudo ao Rio Grande do Sul justifica-se por ser o estado um dos pioneiros e atualmente o terceiro maior produtor de farinha de trigo e um dos maiores produtores de massas alimentícias em âmbito nacional. Os resultados mostram que as indústrias de farinha de trigo e de massas alimentícias localizam-se próximas no estado, e na maioria são de médio e pequeno porte. Além disso, verificou-se que tanto o Brasil como o Rio Grande do Sul não são auto-suficientes na produção de trigo, necessitando de importação. O principal destino dos produtos das indústrias é o próprio Estado, mas a integração vertical na cadeia produtiva ainda é baixa. Constatou-se também que a concentração das indústrias cai de 2002 para 2006 e que existem barreiras à entrada importantes para os ingressantes no setor de farinha de trigo, como a escala mínima de produção, e para os produtores de massas alimentícias, a capacidade já instalada das empresas. Em relação às estratégias competitivas de Porter, a produção com custos mais baixos é a que mais se destaca nas empresas produtoras de farinha de trigo, já nas de massas alimentícias é a diferenciação. Entre as tipologias de Mintzberg, a qualidade do produto é considerada, por ambas as indústrias, como sendo o grande diferencial competitivo. O desempenho das indústrias no período analisado piorou, pois houve queda de lucratividade e perda de participação de mercado.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Currently, it is increasing the search for alternatives to minimize the environmental impact on inputs production. Concrete, highly polluting, is the second most natural material used by man, losing just for the water. Mineral additions have been investigated as partial replacement of cement in concrete, because, besides of providing the use of industrial waste, it can offer improvements in material characteristics. This study analyzed the microstructure of cement pastes composed by sludge produced in water treatment plants (WTP). Seven different traces were investigated: a reference one and 6 traces adding WTP sludge ash in different levels of 5, 10, 15, 20, 25 and 30%. Each trace has been developed to three water/binder (w/b) ratios (0.35, 0.50 and 0.65), ending in 21 different traces, which were studied for different healing ages. Assays of Calorimetry, thermogravimetric analysis (TGA/DTA), setting time, DRX, porosity by mercury intrusion (PIM), chemically combined water, electrical conductivity and hydrogen potential (pH); were performed. From the results, it appears that the increased cement replacement content by WTP sludge ash resulted in an increase in the start and end times of the setting time and decrease in electric conductivity and pH testing. Likewise, a reduction in remnant CH amounts with the increase in WTP sludge ash content shown in TG and XRD tests, as well as reduction in hydration heat because of less formation of side C-S-H. The results for combined chemical water increased when the relations w/b and the WTP sludge ash also increased. When compared to the reference mixture, the increase in WTP sludge ash content resulted in PIM values and the like, although an increase is found in the total area of pores due to change in pore size distribution. / Atualmente a busca por alternativas para minimizar o impacto ambiental na produção de insumos vem aumentando. O concreto é o segundo material mais utilizado pelo homem, perdendo apenas pelo consumo de água. Adições minerais têm sido investigadas como substituição parcial ao cimento no concreto, pois, além de propiciar o aproveitamento de resíduos industriais, podem contribuir nas propriedades do material. Este estudo analisou a microestrutura de pastas de cimento compostas por diferentes teores de cinza de lodo de Estação de Tratamento de Água (CLETA). Foram investigados 7 traços diferentes: um traço de referência e 6 traços com adição de CLETA, para teores de 5, 10, 15, 20, 25 e 30%. Cada traço foi desenvolvido para 3 relações a/ag (0,35, 0,50 e 0,65), totalizando 21 diferentes traços, que foram estudados para diferentes idades de cura. Foram realizados ensaios de calorimetria, análise termogravimétrica (TG), tempo de início e fim de pega, difração de raios X (DRX), Porosidade por Intrusão de Mercúrio (PIM), água quimicamente combinada, condutividade elétrica e potencial de hidrogênio (pH). Dos resultados obtidos, constata-se que o aumento no teor de substituição de cimento por CLETA resultou em aumento nos tempos de início e fim de pega e diminuição na condutividade elétrica e nos valores de pH. Da mesma forma, houve uma redução nos valores de CH remanescente com o aumento no teor de CLETA, evidenciado nos ensaios de TG e DRX, assim como, redução no calor de hidratação devido a menor formação de C-S-H secundário. O teor de água quimicamente combinada aumentou com o aumento na relação a/ag e do de teor de CLETA. Quando comparado à mistura de referência, o aumento no teor de CLETA resultou em valores de PIM semelhantes, embora constate-se aumento na área total de poros, devido a alteração na distribuição de tamanho destes.

Les nanoparticules métalliques ont la particularité de fritter à des températures bien inférieures que les microparticules. Les pâtes de frittage à base de nanoparticules d'argent (Ag) sont commercialisées pour assembler des puces d'électronique de puissance à leur substrat. L’assemblage se fait classiquement entre 200 et 300°C, sous contrainte. Le joint métallique final obtenu possède d’excellentes propriétés de conductivités électrique et thermique. La température de fusion théorique du joint, une fois densifié, est égale à la température de fusion de l’Ag massif (962°C). Cette propriété fait de ce nanomatériau une excellente alternative dans l’électronique de puissance « haute température ». Le coût de l’argent, qui est un métal précieux, reste un frein à l’utilisation de ces pâtes de frittage. Une alternative pour baisser les coûts est de remplacer les nanoparticules d’argent par des nanoparticules de cuivre. Le cuivre possède des propriétés de conductivités très proches de celles de l’argent. Un obstacle majeur à l’intégration de nanoparticules de cuivre dans des pâtes de frittage est la propension du cuivre à s’oxyder. L’oxydation des nanoparticules empêche le frittage et diminue fortement les propriétés mécaniques ainsi que la conductivité du joint métallique final. En plus de cela, le cuivre, même non oxydé, est moins réactif lors du frittage et nécessite des températures plus élevées pour une bonne densification que l’argent. La stratégie choisie pour protéger les nanoparticules de cuivre de l’oxydation a été de les encapsuler dans un polymère ou avec une fine couche d’argent. L’obtention de systèmes cœur-coquille Cu@Ag, en plus d’augmenter la résistance face à l’oxydation, permet d’améliorer le frittage des joints. Une fois densifiés, les joints à base de nanoparticules Cu@Ag sont capables de résister à des contraintes mécaniques élevées. / Metallic nanoparticles have the particularity to sinter at lower temperatures compared to microparticles. Silver (Ag) nanoparticles based sintering pastes are commercially available for assembling power electronics chips to their substrates. The assembly is performed between 200 and 300°C, generally under pressure (Hot Pressing) and the resulting metallic joint has excellent thermal and electrical conductivity properties. The theoretical melting temperature of the resulting densified joint corresponds to the melting temperature of bulk silver (962°C), making the silver nanoparticles an alternative for "high temperature" power electronics compared to traditional solder. Nevertheless, the cost of Ag, which is a precious metal, remains a barrier to the use of these sintering pastes. The cost can be reduced by replacing the silver nanoparticles with copper (Cu) nanoparticles. Copper has conductive properties very close to silver. The major hurdle to the integration of copper nanoparticles in sintering pastes is the proneness of copper to oxidation. The oxidation of Cu nanoparticles prevents sintering and greatly reduces the mechanical properties and conductivity of the final metallic joint. Moreover, copper is less reactive during sintering and requires higher temperatures to densify. We chose to protect copper nanoparticles by encapsulation. In a first step copper nanoparticles were synthetized at laboratory scale and semi-industrial scale. In a second step the copper nanoparticles were encapsulated either with a polymer or very thin layer of Ag. The oxidation properties of the core-shell nanoparticles were studied. In a third step the Cu@Ag nanoparticles were formulated in a paste in order to obtain metallic joints. The sintering and density properties of the metallic joints were evaluated and positively compared to the joints obtained with a commercial Ag based paste. The Cu@Ag core-shell system prevents oxidation but also improves the sintering process.

Tesis por compendio / [ES] El uso de Colocasia esculenta (L.) Schott y Xanthosoma sagittifolium (L.) Schott como materia prima en forma de almidón o harina es una alternativa sostenible y nutritiva al trigo y otros granos. Esta alternativa permite a los agricultores minimizar las pérdidas después de su cosecha y garantizar la seguridad alimentaria ya que sus propiedades nutricionales, digestivas y saludables son reconocidas por la comunidad científica. Sin embargo, la información existente sobre este rizoma dirigida a su aplicación es bastante limitada. Esta tesis expone la caracterización funcional y tecnológica de los almidones obtenidos a partir de cormos y cormelos de Xanthosoma sagittifolium (L.) Schott. Asimismo, se evaluó tecnológicamente el efecto de la combinación de enzimas, hidrocoloides, almidón de patata, harina pregelatinizada sobre la harina de los cormelos de la Colocasia esculenta (L.) Schott en el desarrollo de un pan sin gluten. Además, se evaluaron las propiedades tecnológicas y digestivas de una fórmula básica para puré desarrollada a partir de harina de cormelos de Xanthosoma spp. y Colocasia spp. Además, la revisión bibliográfica realizada permitió poner en contexto los efectos saludables demostrados clínicamente de esta materia prima y sus componentes. Se demostró que existen diferencias significativas entre el almidón de cormos y cormelos de la misma especie. Se concluyó que la harina de Colocasia esculenta (L.) Schott es una buena opción para incrementar el valor nutricional de los panes sin gluten. Entre las estrategias probadas, el pan elaborado a partir de la mezcla con almidón de patata resultó la menos aconsejable. Además, todas las estrategias aplicadas originaron panes con menor índice glucémico que sus homólogos sin gluten reportados en otros estudios. Por primera vez, este trabajo recomienda el uso de harina de cormelos de Xanthosoma sagittifolium (L.) Schott y Colocasia esculenta (L.) Schott y para desarrollar purés con un valor nutricional agregado. La revisión bibliográfica realizada permitió recopilar los efectos demostrados clínicamente, concretamente antihiperglucémicos, antihepatotóxicos, antihipertensivos, hipoglucemiantes, anticancerosos, hipolipidémicos y prebióticos, entre otros, de los compuestos bioactivos presentes en esta planta. / [CA] L'ús de Colocasia esculenta (L.) Schott i Xanthosoma sagittifolium (L.) Schott com a matèria primera en forma de midó o farina, és una alternativa per a minimitzar les perdues després de la seua collita i garantir la seguretat alimentària ja que les seues propietats nutricionals, digestives i saludables són reconegudes per la comunitat científica. Aquesta tesi exposa la caracterització funcional i tecnològica dels midons obtinguts a partir de corms i cormelos de Xanthosoma sagittifolium (L.) Schott. D'una banda és va avaluar tecnològicament l'efecte de la combinació d'enzims, hidrocol·loides, midó de creïlla, farina pregelatinitzada sobre la farina dels cormelos de la Colocasia esculenta (L.) Schott en el desenvolupament d'un pa sense gluten. D'altra banda, es van avaluar les propietats tecnològiques i digestives d'una fórmula bàsica per a puré desenvolupada a partir de farina de cormelos de Xanthosoma spp. i Colocasia spp. que es pot destinar a poblacions vulnerables amb afeccions gastrointestinals, diabètics, celíacs, entre altres. A més, es va realitzar una revisió on s'exposen els efectes saludables demostrats clínicament, dels seus components. Es va demostrar que existeixen diferències significatives entre el midó de corms i cormelos de la mateixa espècie. Per tant, es va concloure que la farina dels cormelos de la Colocasia esculenta (L.) Schott és una bona opció per a incrementar el valor nutricional dels pans sense glútens i entre les estratègies provades, el pa elaborat a partir de la mescla amb midó de creïlla va resultar la menys aconsellable, però tots van mostrar menor índex glucèmic que els seus homòlegs sense glútens reportats en altres estudis. A més, per primera vegada es va recomanar l'ús de farina cormelos de Xanthosoma sagittifolium (L.) Schott i Colocasia esculenta (L.) Schott per a desenvolupar purés amb un valor nutricional agregat. La revisió bibilogràfica realitza va permetre recopilar el efectes demostrats clínicament, en concret antihiperglucémic, antihepatotóxic, antihipertensiu, hipoglucemiant, anticancerós, hipolipidémic i prebiòtic, entre altres, dels compostos bioactius presents en aquest rizoma. / [EN] The use of Colocasia esculenta (L.) Schott and Xanthosoma sagittifolium (L.) Schott as a raw material in form of starch or flour is a nutritious and sustainable alternative to wheat and other grains. This alternative allows farmers to minimize losses after harvest and guarantee food safety since its nutritional, digestive and healthy properties are recognized by the scientific community. Nevertheless, there is still scarce information about these rhizomes that limit their application. This thesis illuminates the functional and technological characterization of the starches obtained from corms and cormels of Xanthosoma sagittifolium (L.) Schott. Likewise, the effect of the combination of enzymes, hydrocolloids, potato starch, pregelatinized flour on Colocasia esculenta (L.) Schott cormels flour toward the development of a gluten-free bread was technologically evaluated. Furthermore, the technological and digestive properties of a basic formula for pastes developed from cormels flour of Xanthosoma sagittifolium (L.) Schott and Colocasia esculenta (L.) Schott was evaluated. In addition, a review was conducted and the health effects clinically demonstrated are exposed. It was shown that there are significant differences between the starch of corms and cormels of the same species. It was concluded that the flour from Colocasia esculenta (L.) Schott cormels is a good option to increase the nutritional value of gluten-free breads. Among the strategies tested, the bread made from mixtures with potato starch was the least desirable, but all strategies tested gave breads with lower glycemic index than gluten-free counterparts reported in other studies. For the first time, this works recommends the use of cormels flour from Xanthosoma sagittifolium (L.) Schott and Colocasia esculenta (L.) Schott was recommended to develop pastes to nutritional value to gluten-free products. In addition, the bibliographic review carried out allowed the compilation and analysis of the clinically demonstrated effects, especifically, antihyperglycemic, antihepatotoxic, antihypertensive, hypoglycemic, anti-cancer, hypolipidemic and prebiotic effects, among others, of the bioactive compounds present in these plants. / Authors acknowledge the financial support of the Spanish Ministry of Science, Innovation and Universities (RTI2018-095919-B-C21), Spanish Ministry of Economy and Competitiveness (Project AGL2014-52928-C2-1-R), the European Regional Development Fund (FEDER) and Generalitat Valenciana (Project Prometeo 2017/189). Tropical Food Research Institute from Cuba provided the rhizomes. / Calle Domínguez, J. (2021). Properties of Malanga Flours and their Use in Pastes and Gluten Free Breads [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/168396 / TESIS / Compendio

Nous étudions expérimentalement l'effondrement d'une colonne granulaire dans un liquide visqueux. Contrairement au cas sec, la morphologie des dépôts n'est principalement plus contrôlée par le rapport d'aspect initial du tas mais par la fraction volumique initiale de la masse granulaire. Deux régimes différents sont identifiés selon l'empilement initial. L'empilement lâche donne lieu à des dépôts minces et longs et la dynamique est rapide. Une surpression du liquide est mesurée sous de la colonne. Pour l'empilement dense, l'étalement final est deux fois moindre, le mouvement est lent et une dépression interstitielle est mesurée. Ces observations suggèrent que la dynamique de l'effondrement granulaire dans un fluide est fortement affectée par le comportement de la dilatance du milieu granulaire.Nous développons ensuite un modèle théorique basé sur des équations diphasiques moyennées dans l’épaisseur prenant en compte les mécanismes de dilatance. L’étude dimensionnelle de notre modèle permet de montrer que l’effondrement d’une colonne est contrôlé par trois paramètres sans dimension : le rapport d’aspect de la colonne, la fraction volumique initiale, et le nombre de grains dans l’épaisseur. On montre également que le temps caractéristique met en compétition le frottement visqueux et la gravité.De ce modèle, nous développons un algorithme de résolution lagrangien. Cette approche, grossière mais robuste, permet d’implanter s sans trop de difficulté. Le code est validé sur des configurations simples sur plan incliné avant de simuler l’effondrement de colonnes granulaires immergées dans la même gamme de paramètres que nos expériences. / Nous étudions expérimentalement l'effondrement d'une colonne granulaire dans un liquide visqueux. Contrairement au cas sec, la morphologie des dépôts n'est principalement plus contrôlée par le rapport d'aspect initial du tas mais par la fraction volumique initiale de la masse granulaire. Deux régimes différents sont identifiés selon l'empilement initial. L'empilement lâche donne lieu à des dépôts minces et longs et la dynamique est rapide. Une surpression du liquide est mesurée sous de la colonne. Pour l'empilement dense, l'étalement final est deux fois moindre, le mouvement est lent et une dépression interstitielle est mesurée. Ces observations suggèrent que la dynamique de l'effondrement granulaire dans un fluide est fortement affectée par le comportement de la dilatance du milieu granulaire.Nous développons ensuite un modèle théorique basé sur des équations diphasiques moyennées dans l’épaisseur prenant en compte les mécanismes de dilatance. L’étude dimensionnelle de notre modèle permet de montrer que l’effondrement d’une colonne est contrôlé par trois paramètres sans dimension : le rapport d’aspect de la colonne, la fraction volumique initiale, et le nombre de grains dans l’épaisseur. On montre également que le temps caractéristique met en compétition le frottement visqueux et la gravité.De ce modèle, nous développons un algorithme de résolution lagrangien. Cette approche, grossière mais robuste, permet d’implanter s sans trop de difficulté. Le code est validé sur des configurations simples sur plan incliné avant de simuler l’effondrement de colonnes granulaires immergées dans la même gamme de paramètres que nos expériences.

Submitted by Ricardo Cedraz Duque Moliterno (ricardo.moliterno@uefs.br) on 2015-09-10T00:55:01Z No. of bitstreams: 1 Nilton C N Santos Tese Geno Cito Endo 10 ago 20h.pdf: 2096544 bytes, checksum: fd3a63f3f5235dae758262d72d8a3bb2 (MD5) / Made available in DSpace on 2015-09-10T00:55:01Z (GMT). No. of bitstreams: 1 Nilton C N Santos Tese Geno Cito Endo 10 ago 20h.pdf: 2096544 bytes, checksum: fd3a63f3f5235dae758262d72d8a3bb2 (MD5) Previous issue date: 2015-06-29 / Pulp therapy for deciduous teeth is the last resort for preventing tooth loss, but among the products used for this, i.e. so-called filling pastes, none is considered to be ideal. The objective of this study, using the micronucleus test on the bone marrow of mice and the comet assay on human lymphocytes, was to evaluate the genotoxic and cytotoxic effects of four filling pastes that are used in this therapy: zinc oxide, calcium hydroxide P.A., mineral trioxide aggregate and an iodoform paste (Guedes-Pinto paste). To perform the micronucleus test, male Swiss mice (Mus musculus) were divided into groups of ten animals each: four groups were each exposed to one of the filling pastes, administered intraperitoneally at dilutions of 1/10, 1/50, 1/500 and 1/1000. Cyclophosphamide was used as the positive control. The negative controls used were the dilution vehicles: dimethylsulfoxide (DMSO) for the Guedes paste and zinc oxide; and phosphate-buffered saline solution (PBS) for the calcium hydroxide P.A. and mineral trioxide aggregate. The animals were sacrificed 24 h and 48 h after the treatment. The bone marrow was extracted, in order to calculate the micronucleus occurrence rate in 1000 polychromatic erythrocytes (PCE) in each of the animals, under an optical microscope (1000 X), in a blinded test. Cytotoxicity was evaluated by determining the PCE/NCE (normochromatic erythrocyte) ratio in 200 erythrocytes/animal. For the comet assay, human lymphocytes were cultured in different dilutions of each of the filling pastes (1:500, 1:750, 1:1000 and 1:2000), for 3 h at 37 ?C, under an atmosphere containing 5% CO2. Two positive controls were used: methyl-methanesulfonate (0.4 ?M) for the calcium hydroxide P.A. and mineral trioxide aggregate; and doxorubicin (0.6 ?M) for the Guedes paste and zinc oxide. Two negative controls were also used here: distilled water for the calcium hydroxide P.A. and mineral trioxide aggregate; and DMSO for the Guedes paste and zinc oxide. Comets were identified by means of fluorescence microscopy (400 X), and 100 of them were counted on each of the three slides that were analyzed for each drug test. The statistical analysis on the results from the micronucleus test was performed using the conditional test for comparing proportions in situations of rare events. Analysis of variance, followed by the Tukey test, was used to assess the PCE/NCE ratio obtained from the different treatments and also to compare the means from the DNA damage indices that were obtained through the comet test, using the Prisma software, version 4.0. The micronucleus occurrence rate was significantly higher among the animals treated with Guedes paste, at all the dilutions tested and at both sacrifice times and also among the animals treated with zinc oxide and sacrificed 48 h after treatment at the dilutions of 1:50, 1:500 and 1:1000. Cytotoxic effects from these pastes were detected in the animals sacrificed at both times. Calcium hydroxide P.A. and mineral trioxide aggregate did not present any cytotoxic or genotoxic effects. The results obtained from the comet assay also showed that zinc oxide and Guedes paste presented genotoxicity, whereas calcium hydroxide P.A. and mineral trioxide aggregate did not. These results show that there is a need to reassess the use of zinc oxide and Guedes paste and provide encouragement for conducting additional studies to evaluate the genotoxicity and cytotoxicity of these pastes. / A terapia pulpar de dentes dec?duos se constitui no ?ltimo recurso de preven??o da perda dent?ria, mas, dentre os produtos empregados para tal, as denominadas pastas obturadoras, nenhum ? considerado como ideal. O objetivo deste trabalho foi avaliar, com o uso do teste de micron?cleo em medula ?ssea de camundongo e do ensaio cometa em linf?citos humanos, os efeitos citot?xicos e genot?xicos de quatro pastas obturadoras utilizadas nesta terapia: ?xido de zinco, hidr?xido de c?lcio P.A., agregado tri?xido mineral e uma pasta iodoformada (pasta Guedes-Pinto). Para realiza??o do teste de micron?cleo, camundongos Swiss (Mus musculus), machos, foram divididos em grupos de dez animais, que foram expostos ?s pastas obturadoras, administradas via intraperitoneal nas dilui??es de 1/10, 1/50, 1/500 e 1/1000. Ciclofosfamida foi utilizada como controle positivo. Os controles negativos foram: dimetilsulf?xido (DMSO) para a pasta Guedes-Pinto e ?xido de zinco; e solu??o salina tamponada (PBS) para o hidr?xico de c?lcio P.A. e agregado trioxido mineral. Os animais foram sacrificados 24h e 48h ap?s tratamento, a medula ?ssea foi extra?da e foram analisados 1000 eritr?citos policrom?ticos (PCE) de cada um dos animais, sob microscopia ?ptica (1000X) e em teste cego. A citotoxicidade foi avaliada pela rela??o PCE (eritr?cito policrom?tico) / NCE (eritr?cito normocrom?tico) em 200 eritr?citos/animal. Para o ensaio cometa, linf?citos humanos foram cultivados nas dilui??es de 1:500, 1:750, 1:1000 e 1:2000 das pastas obturadoras, durante 3h, a 37?C, em atmosfera de 5% de CO2. Foram utilizados dois controles positivos: metil-metanosulfonato (0,4?M) para o hidr?xido de c?lcio P.A. e agregado tri?xido mineral, e doxorrubicina (0,6 ?M) para a pasta Guedes-Pinto e ?xido de zinco. Foram tamb?m dois os controles negativos utilizados: ?gua destilada para o hidr?xido de c?lcio P.A. e agregado tri?xido mineral, e DMSO para pasta Guedes-Pinto e ?xido de zinco. A identifica??o do cometa foi realizada sob microscopia de fluoresc?ncia (400X), sendo computados 100 deles em cada uma das tr?s l?minas analisadas para cada droga teste. A an?lise estat?stica dos resultados do teste de micron?cleo foi realizada com o uso do teste condicional para compara??o de propor??es em situa??o de eventos raros. An?lise de vari?ncia, seguida do teste de Tukey, foram utilizados para avalia??o da rela??o PCE/NCE obtida com os diferentes tratamentos e tamb?m para compara??o das m?dias dos ?ndices de danos ao DNA obtidos no ensaio cometa com o software Prisma vers?o 4.0. A ocorr?ncia de micron?cleos foi significativamente maior nos animais tratados com a pasta Guedes-Pinto em todas as dilui??es testadas, nos dois tempos de sacrif?cio e tamb?m para os animais tratados com ?xido de zinco e sacrificados 48h ap?s tratamento, nas dilui??es 1:50; 1:500 e 1:1000. Efeitos citot?xicos destas pastas foram detectados nos animais sacrificados nos dois tempos. O hidr?xido de c?lcio P.A. e o agregado tri?xido mineral n?o apresentaram efeitos citot?xicos nem genot?xicos. Os resultados obtidos com o ensaio cometa tamb?m apontaram para a genotoxicidade do ?xido de zinco e pasta Guedes-Pinto, e n?o do hidr?xido de c?lcio P.A. e agregado tri?xido mineral. Estes resultados mostram a necessidade de reavalia??o do uso do ?xido de zinco e pasta Guedes-Pinto e suscitam a realiza??o de estudos adicionais avaliando a genotoxicidade e citotoxicidade destas pastas.

Thesis (M.S.)--State University of New York at Binghamton, Department of Mechanical Engineering, 2005. / Includes bibliographical references (leaves 70-72).

Thesis (M.S.)--State University of New York at Binghamton, Thomas J. Watson School of Engineering and Applied Science, Department of Systems Science and Industrial Engineering, 2008. / Includes bibliographical references.

Made available in DSpace on 2014-12-17T14:06:52Z (GMT). No. of bitstreams: 1 AbimaelLM.pdf: 1998740 bytes, checksum: 3bd1ad1da777ebc532ac1fcc9b0a96f4 (MD5) Previous issue date: 2009-03-20 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The low tenacity presented by the Portland cement pastes used in the oil wells cementation has been motivating several researches with attention focused on alternative materials. Additives have been developed to generate flexible pastes with mechanical resistance capable to support the expansions and retractions of the metallic covering of the wells that submit to the steam injection, technique very used to increase the recovery factor in oil reservoirs with high viscosity. A fresh paste with inadequate rheological behavior may commit the cementation process seriously, involving flaws that affect the performance of the paste substantially in the hardened state. This work proposes the elaboration and the rheological analysis of Portland cement pastes with addition of residues of rubber tire in several proportions, with the aim of minimizing the damages provoked in the hem cementing of these wells. By thermogravimetric analysis, the particles of eraser that go by the sieve of 0,5mm (35 mesh) opening and treated superficially with NaOH solution of 1 mol/L presented appropriate thermal resistance for wells that submit to thermal cyclic. The evaluation of the study based on the results of the rheological analysis of the pastes, complemented by the mechanical analysis, thickening, stability, tenor of free water and filtrate loss, being used as parameter a paste reference, without rubber addition. The results showed satisfactory rheology, passive of few corrections; considerable loss of mechanical resistance (traction and compression), compensated by earnings of tenacity, however with established limits for its application in oil wells; satisfactory stability, free water and thickening time / A baixa tenacidade apresentada pelas pastas de cimentos Portland utilizadas na cimenta??o de po?os de petr?leo tem motivado v?rias pesquisas voltadas para materiais alternativos. Aditivos t?m sido desenvolvidos para gerar pastas flex?veis e com resist?ncia mec?nica capaz de suportar as expans?es e retra??es do revestimento met?lico dos po?os que se sujeitam ? inje??o de vapor, t?cnica muito utilizada para aumentar o fator de recupera??o em reservat?rios de ?leo com alta viscosidade. Uma pasta fresca com comportamento reol?gico inadequado pode comprometer seriamente o processo de cimenta??o, implicando em falhas que afetam substancialmente o desempenho da pasta no estado endurecido. Este trabalho prop?e a elabora??o e a an?lise reol?gica de pastas de cimento Portland com adi??o de res?duos de borracha de pneu em diversas propor??es, com o objetivo de minimizar os estragos provocados na bainha cimentante destes po?os. Por an?lise termogravim?trica, as part?culas de borracha passantes na peneira de abertura 0,5 mm (35 mesh) e tratadas superficialmente com solu??o 1 mol/L de NaOH, apresentaram resist?ncia t?rmica adequada para po?os sujeitos ? ciclagem t?rmica. A avalia??o do estudo baseou-se nos resultados da an?lise reol?gica das pastas, complementadas pela an?lise mec?nica, espessamento, estabilidade, teor de ?gua livre e perda de filtrado, utilizando-se como par?metro uma pasta refer?ncia, sem adi??o de borracha. Os resultados mostraram reologia satisfat?ria, passiva de poucas corre??es; consider?vel perda de resist?ncia mec?nica (tra??o e compress?o), compensada por ganho de tenacidade, por?m dentro dos limites estabelecidos para sua aplica??o em po?os de petr?leo; satisfat?ria estabilidade, ?gua livre e tempo de espessamento

Made available in DSpace on 2014-06-11T19:24:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-07-08Bitstream added on 2014-06-13T19:11:27Z : No. of bitstreams: 1 martinelli_l_me_sjrp.pdf: 1675808 bytes, checksum: cfe68f960177993855a48c3037727299 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Neste trabalho foi construído e desenvolvido um secador de leito pulso-fluidizado que utilizou partículas inertes para a secagem de pastas e polpas de frutas. O sistema permitia o controle da vazão do ar de fluidização e de sua temperatura, da pulsação do ar e da vazão de injeção de pasta. Foram determinadas as curvas de fluidização de partículas de vidro e teflon no leito pulso-fluidizado sob diferentes configurações, bem como suas velocidades de mínima fluidização, as quais demonstraram-se próximas às curvas de um secador fluidizado convencional. Experimentos para a avaliação da agitação das partículas foram realizados para que fossem encontradas as melhores condições, determinando-se a existência ou não de pontos mortos no leito. Foi visto que as partículas pertenciam ao grupo D, segundo a classificação de Geldart (1973). Pasta de gesso foi seca no secador pulso-fluidizado para avaliação da produção de pó e do hold-up das esferas nas diferentes condições de operação, as quais tiveram como variáveis os períodos de injeção (fase ativa e inativa), ângulo da válvula borboleta que dava acesso do ar ao leito, temperatura do ar de secagem, velocidade do ar e vazão de pasta no leito. Foi observado que todas as variáveis testadas apresentaram influência na produção de pó e na quantidade de material aderido às partículas inertes. O secador pulsofluidizado foi testado também na secagem de suco e pastas de limão, maltodextrina e tomate, mostrando problemas de adesividade e, no caso de derivados de limão, aglomeração das partículas e colapso do leito. O secador foi utilizado ainda como vibro-fluidizado, quando o sistema de pulsação foi desligado e um sistema de vibração por eixos excêntricos foi acionado, constatando-se que o mesmo apresentou rendimento inferior ao pulso-fluidizado. Um secador do tipo spray dryer foi usado para a secagem... / For this work, a pulse fluidized bed drier that used inert particles for drying pastes and fruit pulps was constructed and developed. The system allowed for the control of fluidized air flow and its temperature, the air pulses and the paste injection flow. The fluidization curves and minimum velocity of fluidization of glass and Teflon particles were determined in the pulse fluidized bed. Experiments to evaluate the agitation of particles were done to find the best agitation conditions, determining the existence or not of dead spots in the bed. It was seen that the particles belonged to D group, as per Geldart (1973) classification. Plaster paste was dried in the pulse fluidized dryer to evaluate the production of powder and hold-up of the spheres under different operational conditions which were variations of the periods of paste injection (active and inactive phase), angle of the butterfly valve which gave air access to the bed, air drying temperature, air speed and paste flow. All tested variables influenced the powder production and the amount of material adhered to inert particles. The pulse fluidized bed drier was also tested for drying lemon juice and paste, maltodextrina and tomato, showing adhesive problems and, with the lemons, an agglomeration of particles and a collapsed bed. The dryer was also used as a vibro fluidized bed when the pulsation system was turned off and a vibration system with eccentric axles was set in motion, it was seen that the vibro fluidized bed had a lower yield than the pulse fluidized bed. A spray drier was used to dry lemon juice with maltodextrina, and it was found that a minimum of 65% of additional maltodextrina was needed. Physic-chemical testes were done from the powders obtained from the spray drying. These testes were for humidity, flowability, degree of agglomeration, higroscopicity, dispersibility, color determination and water activity... (Complete abstract click electronic access below)