924 resultados para Tolerância ao calor
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Fondo Margaritainés Restrepo
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Os trabalhos publicados sobre estudos conducentes a obtenção de propriedades da litosfera na Península Ibérica, indicam uma anomalia na espessura da litosfera no SW da Península referida. Um dos parâmetros utilizados nos modelos referidos, é o valor do fluxo de calor característico da região. O trabalho que propomos apresentar consiste na análise detalhada dos dados de fluxo de calor obtidos no sul de Portugal (Zona Sul Portuguesa e parte da Zona de Ossa Morena ). Os valores obtidos são relativamente elevados, devido a gradientes de temperatura elevados e/ou valores elevados de condutividade térmica, não sendo possível obter um valor de fluxo de calor característico de toda a região estudada. Será feita uma análise detalhada dos valores obtidos, tentando relacioná-los com características próprias dos locais onde foram realizadas as medições.
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Tesis (Zootecnista). -- Universidad de La Salle. Facultad de Ciencias Agropecuarias. Programa de Zootecnia, 2014
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Dissertação (mestrado)—Universidade de Brasília, Faculdade UnB Gama, Programa de Pós-graduação em Integridade de Materiais da Engenharia, 2015.
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2011
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The oil companies in the area in general are looking for new technologies that can increase the recovery factor of oil contained in reservoirs. These investments are mainly aimed at reducing the costs of projects which are high. Steam injection is one of these special methods of recovery in which steam is injected into the reservoir in order to reduce the viscosity of the oil and make it more mobile. The process assisted gravity drainage steam (SAGD) using steam injection in its mechanism, as well as two parallel horizontal wells. In this process steam is injected through the horizontal injection well, then a vapor chamber is formed by heating the oil in the reservoir and, by the action of gravitational forces, this oil is drained down to where the production well. This study aims to analyze the influence of pressure drop and heat along the injection well in the SAGD process. Numerical simulations were performed using the thermal simulator STARS of CMG (Computer Modeling Group). The parameters studied were the thermal conductivity of the formation, the flow of steam injection, the inner diameter of the column, the steam quality and temperature. A factorial design was used to verify the influence of the parameters studied in the recovery factor. We also analyzed different injection flow rates for the model with pressure drop and no pressure drop, as well as different maximum flow rates of oil production. Finally, we performed an economic analysis of the two models in order to check the profitability of the projects studied. The results showed that the pressure drop in injection well have a significant influence on the SAGD process.
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Nowadays, most of the hydrocarbon reserves in the world are in the form of heavy oil, ultra - heavy or bitumen. For the extraction and production of this resource is required to implement new technologies. One of the promising processes for the recovery of this oil is the Expanding Solvent Steam Assisted Gravity Drainage (ES-SAGD) which uses two parallel horizontal wells, where the injection well is situated vertically above the production well. The completion of the process occurs upon injection of a hydrocarbon additive at low concentration in conjunction with steam. The steam adds heat to reduce the viscosity of the oil and solvent aids in reducing the interfacial tension between oil/ solvent. The main force acting in this process is the gravitational and the heat transfer takes place by conduction, convection and latent heat of steam. In this study was used the discretized wellbore model, where the well is discretized in the same way that the reservoir and each section of the well treated as a block of grid, with interblock connection with the reservoir. This study aims to analyze the influence of the pressure drop and heat along the injection well in the ES-SAGD process. The model used for the study is a homogeneous reservoir, semi synthetic with characteristics of the Brazilian Northeast and numerical simulations were performed using the STARS thermal simulator from CMG (Computer Modelling Group). The operational parameters analyzed were: percentage of solvent injected, the flow of steam injection, vertical distance between the wells and steam quality. All of them were significant in oil recovery factor positively influencing this. The results showed that, for all cases analyzed, the model considers the pressure drop has cumulative production of oil below its respective model that disregards such loss. This difference is more pronounced the lower the value of the flow of steam injection
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Dissertação (mestrado)—Universidade de Brasília, Departamento de Botânica, Programa de Pós-Graduação em Botânica, 2016.
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2016
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Devido às normas ambientais atualmente em vigor que restringem a quantidade de gases poluentes emitidos para a atmosfera pelos automóveis, e também pela cada vez maior consciencialização para os problemas ambientais que o consumo de combustíveis fósseis acarreta, assim como devido ao cada vez mais elevado preço dos mesmos, os construtores automóveis têm como principal objectivo a redução do consumo do combustível e consequente diminuição de emissão de poluentes. Os sistemas de reaproveitamento da energia térmica desperdiçada nos motores de combustão interna (MCI), podem contribuir de forma significativa para o aumento da eficiência de conversão de energia em veículos equipados com MCI. O presente estudo é dedicado ao desenvolvimento de um sistema de recupereração desta energia desperdiçada, recorrendo ao ciclo de Rankine, com ênfase no desenvolvimento da montagem experimental, na avaliação do desempenho de diferentes geometrias de evaporador e no estudo das incertezas experimentais. Tendo em conta as várias restrições de projeto (compacidade, perda de carga e potência recuperada por unidade de volume) o presente trabalho permitiu identificar a geometria do evaporador mais adequada.
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The recent values of heat flow data obtained for Greenland and West Antarctica are higher than it was supposed. In West Antarctica, values higher than 200mW/m2were found (Schroeder et al,2014) and in Greenland, values higher than 140 mW/m2 were detected in the Central part (Petrunin et al,2013). Thermal conductivity values of ice are relatively low at atmospheric pressure. This means that if we consider heat flowing by conduction, near the surface of the globe, with this heat flow values, the thermal gradients mill be elevated. A possible reason presented for the high heat flow values in Greenland is the existence of a thin lithosphere. The study of the ice melting near the poles is related with the changes in sea level. Obtaining this parameter is difficult. The time interval with measurement is not enough to obtain clear information about the past..The spatial distribution of heat flow shows clearly zones in the oceans with high values. How can this heat influence water movements in that regions and the temperature in the oceans?
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Heat flow density determinations have been done in a large part of the surface of the planet Earth. As a consequence, new heat flow density maps and estimates of global values of heat lost through the surface of the Earth has been done. In this work, we present some problems related with this matter. In the last three decades, we have learn many things related with heat flow, but there are yet many problems without answers.
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2016
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Este trabalho teve por objetivo avaliar a tolerância de isolados de levedura para aplicação no controle biológico de podridões pós-colheita de frutos em elevadas temperaturas e baixa disponibilidade de água. As leveduras foram inoculadas em meio de cultivo líquido contendo um gradiente de concentrações de polietilenoglicol 6000 de forma a alcançar potenciais osmóticos de 0 Mpa, -2 Mpa, -5 Mpa, -10 Mpa, -15, -20 Mpa, e incubados em BOD nas temperaturas de 15 °C, 20 °C, 25 °C, 30 °C, 35 °C e 40 °C. A partir da análise das curvas de crescimento obtidas, verificou-se que os isolados Sacharomyces sp. L10 e S. boulardi L7K apresentaram a maior suscetibilidade aos estresses abióticos, com crescimento próximo à zero nas condições restritivas de cultivo. O isolado Sacharomyces cerevisiae LF apresentou a maior tolerância à combinação dos fatores analisados, seguido de Pichia kudriavzevii L9, demonstrando maior potencial para aplicação em condições de campo para a prevenção de infecções de patógenos quiescentes.