948 resultados para Combustíveis Fósseis


Relevância:

10.00% 10.00%

Publicador:

Resumo:

In this work concepts of flammability limits of anhydrous and hydrated ethanol to pressures below atmospheric, using the Dalton model for gaseous mixtures. Theoretical and experimental methods for determining the boundaries and the influence of parameters such as concentration, temperature and pressure were introduced. Analyzes from partial pressures of fuel vapor and correlations with temperature and total pressure were made. Finally presents an overview of aviation fuels, their requisites and trends in the use of biofuels in commercial aviation industry

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The current competitiveness of the market has generated the need to minimize the cost of production companies in any field of activity, aimed at reducing the cost of production, the cost of purchasing and manufacturing processes interruption of manufacturing processes for possible maintenance. In this sense, companies are seeking methods to improve and streamline their production line. In ceramics industries, cooking the pieces is the portion of the production process that influences the total costs. The oven construction and maintenance represent a large portion embedded in the cost of the final ceramic product. The proposal for a type of oven for baking the parts that takes into account a better burning process, knowledge of the causes of disease and cost analysis of purchasing both of the constituent materials and labor for its construction, can be significant importance to the composition of final product costs or time analysis of ROI. It is proposed a streamlined design of an oven that takes into account the positive characteristics of the furnaces already built and that the experience has endorsed, and also others that are added at the end, lead to a reduction in production cost, the cost income and the number of pathologies arising from wear of the furnace along the lifespan. Therefore, according to the experiences gained over the years in the construction of furnaces and experience of manufacturing of ceramic, it is proposed a project that has an oven improvement over those now being built and that include, among other topics, economy in fuel burning, streamlining the building process

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Nowadays, the biggest part of the world's energy supply comes from fossil fuels and nuclear. However, the current need of the society for the preservation of the environment and wise use of natural resources, has favored the search for alternative energy sources and improvement of energy efficiency. In this new scenario, companies are beginning to mobilize in order to adapt its facilities to renewable energy. Solar, with its immense potential, not really exploited yet, can be very useful for companies that want to beat their sustainability goals. Given these facts, the aim is to evaluate the economic viability of introducing a solar water heater which uses a colorless PET bottle as one of its components in a plant. The hot water generated will heat the air of a paint booth and a warm house, reducing energy consumption, since they are heated by electric heaters

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A dosagem do etanol durante a produção de medicamentos, bebidas e combustíveis tem se mostrado bastante importante para o aumento de rendimento dos processos e qualidade dos produtos. Embora existam vários métodos para determinar a concentração do etanol, os enzimáticos são os mais interessantes por serem rápidos, precisos, de fácil manuseio e baixo custo. O objetivo geral desse trabalho foi a elaboração de um Kit de quantificação enzimática de etanol, utilizando a enzima álcool desidrogenase I recombinante de S. cerevisiae (Adh1). Para isso, o gene codificador da enzima álcool desidrogenase I (ADH1) de levedura foi clonado no vetor pET28a para expressão em E. coli (BL21). Em seguida, a produção e solubilidade da enzima álcool desidrogenase I foi determinada, sendo definida uma condição ideal de produção e purificação da proteína recombinante por cromatografia de afinidade. A atividade enzimática da álcool desidrogenase I purificada foi determinada através de ensaios já padronizados na literatura (UV), bem como sua estabilidade em diversas condições de tempo e temperatura. Os resultados obtidos aqui demonstraram que a enzima obtida apresentou boa atividade biológica in vitro, com sensibilidade na detecção de no mínimo 2,3 x 10–4 g/L de etanol em 2 minutos. Além disso, a proteína purificada teve sua atividade preservada quando estocada a - 20°C durante 120 dias, características que possibilitarão que a enzima álcool desidrogenase I recombinante, purificada pela metodologia apresentada nesse trabalho, seja utilizada em um kit de quantificação enzimática de etanol rápido, preciso e de baixo custo

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The technologies are advancing at a pace so expressive that allow the increase of the power quality from generation until the distribution to end customers. This improvement has been made possible through the automation of the energy that follows to a better quality of the energy provided, a lower energy supply disruptions and a very short recovery time. The trend of today and the near future is the distributed energy generation. To keep the automated control of the chain, the presence of Smart Grids is needed and that will be the most efficient and economical way to manage the entire system. Within this theme, is going to be necessary analyze the electric cars that promise to promote a more sustainable transport because it doesn’t uses fossil fuels, and more healthy because it does not emit pollutants into the atmosphere. The popularization of this type of vehicle is estimated to happen in a few decades and the case study analyzing its influence on the demand of the electrical system is something that will be very important in the near future. This paper presents a study of the influence of the inclusion of charges refering to electric cars

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Atualmente a China é um ator essencial do cenário econômico mundial, sendo também um grande demandante de matérias primas para manter seu acelerado crescimento, resultando assim em importante e estratégico para a região latinoamericana, sobretudo, por ser um grande comprador. Por sua importância econômica, estratégica e demográfica a China se destaca em relação à maioria dos países do mundo sendo não apenas um ator chave, responsável por grandes mudanças ocorridas no nível e estrutura da demanda mundial, mas também importante fonte de recursos financeiros para manter os equilíbrios internacionais. Através da discussão das relações de comércio entre Brasil e China buscamos analisar os principais resultados em termos econômicos e sociais, principalmente a atuação do Brasil enquanto ator global dado sua importância crescente na dinâmica mundial. A intenção desta pesquisa é entender as dimensões da relação com o país asiático, a partir do posicionamento do Brasil como um dos principais parceiros comerciais de China, sobretudo como exportador de produtos primários. Em termos de exportações realizadas por setores desde o Brasil para a China existe uma grande concentração nos recursos naturais de matérias primas, particularmente os minérios, alimentos, e combustíveis; trata-se de um pequeno hall de produtos com baixo nível de processamento

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Aiming to reduce the cost of electrocatalysts and a greater resistance to CO poisoning this work was to study the adsorption and oxidation of carbon monoxide on ordered intermetallic phases AuIn, AuSb2, AuSn, PdSb and PdSn using voltammetric techniques in alkaline electrolyte solution. The results suggest that the AuSn and PdSn intermetallics has some form of resistance to CO poisoning. It is assumed that this behavior is a result of electronic effect and the effect of the third body has been achieved by adding a second metal to Au and Pd. However, further studies should be conducted to confirm this hypothesis as to test these materials as electrocatalysts in the reaction of oxidation of fuels

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A importância do estudo da paleontologia está no seu caráter integrador, reunindo conhecimentos de várias áreas, o que pode contribuir para que os alunos do ensino básico entendam a história da vida no planeta, encarando a evolução como um processo contínuo e bem evidenciado no qual também estamos inseridos. No contexto de pequena presença do ensino da paleontologia na Educação Básica, outros espaços de educação não formal ganham força na transmissão desses conhecimentos à população e, dentre estes espaços, na área da paleontologia, encontram-se as exposições de fósseis. Estas permitem que os conhecimentos desenvolvidos na universidade e que normalmente ficam restritos ao âmbito universitário sejam levadas ao conhecimento de um grande número de alunos, contribuindo para a formação e alfabetização científica. A partir desta perspectiva, o presente estudo teve como objetivo o desenvolvimento e a avaliação de uma exposição de fósseis e réplicas para os alunos do ensino básico da rede pública das escolas de Botucatu e região. Através dessa exposição, chamada Paleo Expo, pretendeu-se que os alunos conhecessem a história da vida na Terra, tivessem contato com os principais eventos evolutivos e entendessem a evolução como um processo contínuo e bem evidenciado, contribuindo para o enriquecimento dos conhecimentos dos visitantes, aguçando a curiosidade e gerando reflexões. A exposição, destinada a alunos de sexta a oitava series do ensino fundamental, priorizou a participação ativa dos alunos e contou também com atividades complementares, que consistiram em um jogo educativo e uma apresentação de informações sobre como são realizadas as pesquisas em paleontologia. A Paleo Expo, de um modo geral, atingiu seus objetivos e os alunos se mostraram estimulados e participativos. Pode-se considerar, pelos dados coletados, que a experiência... (Resumo completo, clicar acesso eletrônico abaixo)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The uninterrupted rise in emission of greenhouse gases open way to the use of biofuels, due to politics that focus on fuel safe, clean and renewable. The use of microalgae for biodiesel production has been described as one of the most promising sources of biomass for biofuels. The aim of this study was to evaluate the extraction and lipid profile of the microalgae Dunaliella tertiolecta, Isochrysis galbana and Tetraselsim gracilis. The extractions were performed with solvents chloroform /methanol and petroleum ether. The lipid profile was analyzed by gas chromatography after transesterification.The petroleum ether showed more efficiency in the extraction, the best result obtained was in the microalgae D. tertiolecta with 19.52% of lipid. The lipid profile analysis indicated a biodiesel stable to oxidation and elevated viscosity

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This research has as main objective the analysis of the auto industry has done to reduce disposal of solid waste in its production process as much as to facilitate the recycling of cars after they complete their life cycle. Despite the auto industry is not one of the most polluting in terms of its production process, it produces a good that is causing major pollution. In despite of the great current concern in seeking to reduce the emissions of pollutants by vehicles, as important as the quest for cleaner fuels is the study of how to dispose of old cars. Even if the car production does not increase significantly each year in relative terms, we must consider the fleet of used cars that still circulates in the world. Ending the mammoth “cemeteries” of automobiles, however, it is not so easy, even because the car is composed of various materials, which in many cases are not easily separable. In addition to an overview, the research seeks to examine the possible advances in Brazil related to the process of auto recycling

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The increase in the oil price and the current trend of using renewable raw materials for the production of chemicals renew the interest in the production of biobutanol that, produced by fermentation of agricultural raw materials, can be used as a component of gasoline and diesel. With the commercialization of new fuels, environmental damages due to spills can occur. Among other techniques, the clean-up of these contaminated areas can be achieved with bioremediation, a technique based on the action of microorganisms, which has the advantage of turning hazardous contaminants into non toxic substances such as CO2, water and biomass. Thus, bearing in mind the use of biobutanol in the near future as a gasoline extender and due to the lack of knowledge of the effects of butanol on the biodegradation of gasoline, this work aimed to assess the aerobic biodegradation of butanol/gasoline blends and butanol/diesel (20% v/v), being the latter compared to the ethanol/gasoline blend and biodiesel/diesel (20% v/v), respectively. Two experimental techniques were employed, namely the respirometric method and the redox indicator 2,6-dichlorophenol indophenol (DCPIP) test. In the former, experiments simulating the contamination of natural environments were carried out in biometer flasks, used to measure the microbial CO2 production. The DCPIP test assessed the capability of four inocula to biodegrade the fuel blends. In butanol/gasoline experiments the addition of the alcohols to the gasoline resulted in positive synergic effects on the biodegradation of the fuels in soil and...(Complete abstract click electronic access below)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

L’audit, c’est un outil de gestion très important pour que les organisations puissent accomplir la réussite. Selon le fait qu’il n’y a pas des modèles d’aide à l’audit, il existe une opportunité de recherche. En considerant les Méthodes d’Aide à la Décision, il y a des plusieurs type d’applications. L’objectif de la recherche c’est la proposition d’un modèle capable de sélectionner des processus pour faire l’audit dans une distributeur de carburant en considerant la prise de décision en groupe. La modélisation normative empirique c’est la méthode de recherche utilisée. Un modèle qui utilise l’Analytic Hierarchy Process (AHP) et la prise de décision en groupe a été proposé face aux difficultés d’un département d’Audit Interne. Le modèle proposé présente les poids des processus et permet leur priorisations dans un scénario determiné. Pour l’application de ce modèle présenté, on a utilisé cinq critères et 26 alternative (processus). L’information de jugement a été bien founi par trois spécialistes du département. Quelques rendez-vous avec les participants ont été pris pour obtenir et réviser les donnés ainsi que discuter les résultats. Les résultats obtenus par le modèle permettent d’identifier les processus qu’il faut plus d’attention. L’équipe a considéré le modèle comme une proposition d’aide à la prise de décision très pertinent pour le département d’Audit Interne

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Geophysics studies in areas impacted by petroleum derivatives describe abnormalities of both low and high electrical resistivity (the opposite of electrical conductivity), confirmed as contaminant phase by chemical analysis: this contradiction can be explained by degrading processes that naturally occur and create sub products that can change the environment conductivity. Monitoring the variation of the parameters mentioned serves as a comparative basis to the variation in geoelectrical parameters, which identified the correlation between the same contaminant parameters and the difference between their behavior studied apart, as well as its relations with the biodegradation process. The results are applied to the fuel distribution and storage sectors, leading to the diagnosis and monitoring of possible groundwater contamination scenarios, and the knowledge of the area exposure time to the contaminant, besides the better remediation alternative and impacts control. Among some conclusions, the most significant are the decrease in conductivity over time, so as the increase in Eh value in the gasoline contaminated tank, as well as the decrease in the pH value in the second tank with ethanol, which can be attributed to its degradation. Comparing the variations in both tanks, it is evident that Eh, pH and electrical conductivity do not behave temporally in a similar way, although some correlations between Eh and pH can be related.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Pós-graduação em Microbiologia Agropecuária - FCAV

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Inúmeros são os trabalhos versando sobre a contaminação de águas e solos por metais potencialmente tóxicos, ou metais pesados. O destaque sempre é dado para chumbo, mercúrio e, mais recentemente, cádmio que, também é, comprovadamente, carcinogênico. Em contrapartida, estudos sobre a toxicidade do manganês são raros devido, provavelmente, ao fato do mesmo ser um metal essencial à vida. Porém, absorvido em doses elevadas pelo organismo, pode provocar uma série de patologias e disfunções, algumas muito graves como déficit intelectual. Nesse trabalho procurou-se avaliar a concentração de manganês em amostras de solos cultivados e não cultivados de várias regiões do Estado de São Paulo. Surpreendentemente, algumas dessas amostras apresentaram teores até cinco vezes mais elevados do que o limite estabelecido como alto pelo Governo do Estado de São Paulo (que é de 5 mg/dm³). A provável fonte desse excesso reside na liberação de produtos de combustão e/ou na forma de aditivos aos combustíveis.