959 resultados para indirizzo :: 912 :: Macchine a fluido


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Fins are a way to improve heat exchange, they increase the surface area in contact with the fluid medium. Besides widely used in industries, such extended surfaces appear in various formats and can be compared for their efficiencies in order to select the most profitable. This work proposes a new profile of fin so as to increase the perimeter of the base. The raised profile cross sectional area is constant and is also compared to other types. Here are shown the deductions of equations for this new element, and through the perimeter and graphs calculated results are compared

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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A psoríase é uma doença inflamatória de pele e das articulações, e por acometer um órgão visível como a pele, resulta em transtornos psicológicos relacionados à auto-estima do paciente. Dentre os fármacos empregados no tratamento, destaca-se o metotrexato para uso sistêmico que, embora eficiente, possui a desvantagem de causar efeitos colaterais tóxicos como a hepatotoxicidade e a mielotoxicidade. Para minimizar tais efeitos e aumentar a eficácia do fármaco, o trabalho teve por objetivo desenvolver e caracterizar sistemas nanoestruturados para administração cutânea do metotrexato. Para realizar esse estudo, inicialmente foram preparadas diferentes formulações constituídas por silicone fluido de copolímero glicol (DC® 193), poliéter funcional siloxano (DC® 5329) e água destilada. O metotrexato foi incorporado numa concentração de 1,25% (p/v), com auxílio de solução de hidróxido de sódio 1M, sendo ajustado o pH final da formulação para 7,0 com ácido clorídrico 0,1M. Foram selecionadas algumas regiões do diagrama para serem submetidas a testes de estabilidade, empregando o teste de centrifugação, determinação do pH, condutividade iônica, índice de refração e avaliação das características organolépticas. Foi realizada a análise reológica empregando reômetro, modelo RS-1 (HaakeRheostress). As estruturas das formulações foram analisadas por microscopia de luz polarizada. As amostras com maior concentração de tensoativo apresentaram aspecto transparente, sendo submetidas à análise com microscópio de luz polarizada, onde evidenciou-se estruturas conhecidas como “cruzes de malta”, indicativas de fase lamelar. Foram selecionadas 3 formulações com concentração de 40% de tensoativo, variando-se as proporções de água e óleo, nas quais foram incorporadas o metotrexato... (Resumo completo, clicar acesso eletrônico abaixo)

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Os valores encontrados para a viscosidade sanguínea tendem a aparecer com diferenças significativas, de acordo com o sexo, avançar da idade e uso de substâncias. Pelo fato de o sangue ser um fluido não newtoniano, não podemos expressar sua viscosidade em termos absolutos sem que sejam levadas em conta as condições em que a mensuração é feita. Estudos anteriores destacaram a importância esta medida, considerando o efeito da idade, o uso de substâncias, bem como sua relação com Fluxo Sanguíneo Regional Cerebral, o que pode indicar correlação com declínios cognitivos. Entretanto, a prática médica carece ainda de um método simples e clinicamente prático para a verificação desta medida, além de valores de referência. Como passo inicial no sentido de padronizar os procedimentos e condições do processo de medição, avaliamos a quantidade mínima de amostra necessária para a medição da viscosidade sanguínea, utilizando este equipamento. Um total de 20 amostras de sangue foram coletadas de indivíduos saudáveis, entre 18 e 60 anos, em tubos com EDTA, e cada amostra dividida em 9 sub-amostras (de 600μl, 550μl, 500μl, 450μl, 400μl, 350μl, 300μl, 250μl e 200μl), totalizando, portanto, um total de aproximadamente 180 medições. A quantidade de 200 μl apresentou diferenças significativas com relação à primeira medida obtida, quando comparada com todas as demais quantidades (p<0,001), o que indica que com o uso desta quantidade, não é possível obter resultados confiáveis, pois existe alteração nos valores de VS obtidos relacionada à quantidade de material utilizado. Considerando a menor quantidade, bem como, que estivesse dentro da faixa de variação aceitável de 0,2 mPa.s, e a qual não apresentasse diferença significativa quando comparadas às demais (p>0,05), foi verificada a quantidade de 250 μl como a mais eficiente... (Resumo completo, clicar acesso eletrônico abaixo)

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With the growing world energy demand mainly from developing countries like Brazil, Russia, India and China, the search for efficient sources of energy becomes a challenge for the coming years. Among the most widely used alternative sources, biomass is the one that grows in a more pronounced way. This study will assess the real possibility of having it as a heat source in an Organic Rankine Cycle, which employ heat transfer fluids as working fluids instead of water. From a regional data collection in agricultural production and their potential rice production and the resulting husk was defined as more appropriate. The availability of husks together with an amount of eucalyptus wood, provided by a company in the region on a monthly basis, were analyzed, and the low participation of the wood was discarded by the thermal contribution of little significance. Based on this, it was established the calorific value of fuel for thermodynamic calculations and the cycle to be used. It was then carried out the choice of working fluid from the literature and their availability in the library of software used for the simulations, the Engineering Equation Solver - ESS. The fluid most appropriate for the burning of biomass, Octamethyltrisiloxane (OMTS), was not included in the software and so the R227ea and R134a were selected. After the initial parameters modeling definition, as condensing temperature, efficiency and live steam conditions, the simulations were performed, and only the R227ea remained within the feasible thermodynamic and technological ranges. With this fluid the turbine power output was 265.7 [kW] for a scenario of 24 hours/day burning, 800.3 [kW] to biomass burning for 8 hours/day and 2134 [kW] for burning only 3 hours/day. The thermal efficiency of the cycle remained in the range of 6%, and for plants operating with the most... (Complete Abstract click eletronic access below)

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Pós-graduação em Medicina Veterinária - FCAV

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The steady increase in the price of oil and its derivatives, carbon credits, the concern with the environment combined with the precipitation of rain water and lack of water resources that Brazil has suffered in 2014 caused a migration of participation sources of energy in the Brazilian energy matrix. The hydropower sector suffered big drop at 2013 and is suffering so far, contributing thus to the generation and cogeneration of thermal energy using renewable energy sources such as: sugarcane bagasse, wood chips, rice husks, among others. The selling price of the electricity market reached the level of R$ 807, 00 MWh in January 2014 (Source: ANEEL), heating the Brazilian thermoelectric sector. Although thermoelectric use in bulk water as vaporizing fluid to produce electricity and use in various processes, water reuse plans have become an important factor in these industries. The increased use of biomass has been the bagasse which is allied to the sugarcane sector, strong market in Brazil, and consists basically use the rest of sugar cane, sugarcane industries that would play out. The sugar and ethanol industry is very unstable and only lasts for 6-8 months a year, and the remaining time in the period known as between crop that corresponds to the planting and harvesting of sugarcane and then enter the period of vintage which is the constant cane harvesting and crushing it. This instability of the market and the thermoelectric idle period leads the thermoelectric industries to seek other sources of renewable energy, such as wood chips (pine, Eucalyptus, Orange), rice husk, sorghum among others, to not be dependent on alcohol sector. The present work aims to study the use of wood chips as an alternative biomass for burning a fuel that essentially uses bagasse, the thermoelectric in question consists of two boilers that produce together 350 t / h ... (Complete Abstract click electronic access below)

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The present work resulted from a study about coolant filtration systems in industries with metalworking process in large scale. The filtration and element filter world markets move billions of Reais per year and have a promissory future considering that with the global requirements of sustainable economic development, many companies invest in new filtering technology. Either known as coolant or cutting fluid, it is used to lubricate e cool parts during machining and is necessary due to the high volume demanded in the several machining operations and to the high cost of the product. Therefore, there is the need for recycling the product after its use. The work shows the technology and fundamentals of filtration as well as different filtering elements, filtration systems and scale contamination used in the industry. Also, there is a differentiation between filtration of the surface type (cake) and depth filtration and shows the basic theory of filtration by mathematic models in different operational conditions. Ultimately, project criteria for a coolant filtration system selection is shown followed by technical-operational details of a real vacuum filtration system and a case study aiming the operational cost reduction of the system

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Pós-graduação em Engenharia Mecânica - FEIS

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Pós-graduação em Engenharia Mecânica - FEIS

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Pós-graduação em Biociências - FCLAS

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Pós-graduação em Engenharia Mecânica - FEIS

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Despite the strong valorization of the esthetics and its relationship with restorative materials, the biological principles of any clinical procedure are extremely important to maintain the vitality of the dentin-pulp complex. Dentin and pulp tissue are susceptible to different kinds of irritants such as toxins from microorganisms, traumatic procedures of cavity preparation, as well as toxic components released by restorative materials applied in non recommended clinical situations. Initially, the pulp responds to irritation by starting an inflammatory reaction which involves outward movement of dentinal fluid and intratubular deposition of immunoglobulins, upregulation of odontoblast activities, presence of immune cells and their cytokines as well as local expression of neuropeptides and chemokines. After these initial events, the inflammation process can be resolved associated or not to sclerotic dentin formation and reactionary dentin deposition. If high intensity offensive stimuli are applied to the dentin-pulp complex, death of odontoblasts takes place and consequently pulp ageing or even partial necrosis of this tissue may occurs. Thereby, clinicians need to be aware about the physiological and pathological features of the dentin-pulp complex as well as the possible biological consequences of different clinical procedures. In this way, the dentists should be able to carry out minimally aggressive operative techniques and to select the more appropriate restorative materials for each specific clinical situation in order to obtain excellent clinical results associated to the maintenance of pulp vitality.