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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
321

Development Of A Navier-stokes Solver For Multi-block Applications

Erdogan, Erinc 01 September 2004 (has links) (PDF)
A computer code is developed using finite volume technique for solving steady twodimensional and axisymmetric compressible Euler and Navier-Stokes equations for internal flows by &ldquo / multi-block&rdquo / technique. For viscous flows, both laminar and turbulent flow properties can be used. Explicit one step second order accurate Lax-Wendroff scheme is used for time integration. Inviscid solutions are verified by comparing the results of test cases of a support project which was supported by ONERA/France for Turkey T-108, named &ldquo / 2-D Internal Flow Applications for Solid Propellant Rocket Motors&rdquo / . For laminar solutions, analytical flat plate solution is used for planar case and theoretical pipe flow solution is used for axisymmetric case for verification. Prandtl turbulent flow analogy is used in a flat plate solution to verify the turbulent viscosity calculation. The test cases solved with single-block code are compared with the ones solved with multi-block technique to verify the multi-block algorithm and good similarity is observed between single-block solutions and multi-block solutions. For the burning simulation of propellant of Solid Propellant Rocket Motors, injecting boundary is used. Finally, a segmented solid propellant rocket motor case is solved to show the multi-block algorithm&rsquo / s flexibility in solving complex geometries.
322

Modelling vehicle emissions from an urban air-quality perspective:testing vehicle emissions interdependencies

Dabbas, Wafa M January 2010 (has links)
Doctor of Philosophy(PhD) / Abstract This thesis employs a statistical regression method to estimate models for testing the hypothesis of the thesis of vehicle emissions interdependencies. The thesis at the beginnings, reviews critically the formation of emissions in gasoline-fuelled engines, and also reviews existing and emerging models of automotive emissions. The thesis then, presents the relationships between the urban transport system and vehicle emissions. Particularly, it summarises different types of emissions and the contributory factors of the urban transport system to such emissions. Subsequently, the thesis presents the theory of vehicle emissions interdependencies and the empirical framework for testing the hypothesis of the thesis. The scope of testing the hypothesis of the thesis is only limited to gasoline-fuelled conventional vehicles in the urban transport environment. We use already available laboratory-based testing dataset of 542 passenger vehicles, to investigate the hypothesis of the thesis of vehicle emissions interdependencies. HC, CO, and NOX emissions were collected under six test drive-cycles, for each vehicle before and after vehicles were tuned. Prior to using any application, we transform the raw dataset into actionable information. We use three steps, namely conversion, cleaning, and screening, to process the data. We use classification and regression trees (CART) to narrow down the input number of variables in the models formulated for investigating the hypothesis of the thesis. We then, utilise initial results of the analysis to fix any remaining problems in the data. We employ three stage least squares (3SLS) regression to test the hypothesis of the thesis, and to estimate the maximum likelihood of vehicle variables and other emissions to influence HC, CO, and NOX emissions simultaneously. We estimate twelve models, each of which consists of a system of three simulations equations that accounts for the endogenous relations between HC, CO and NOX emissions when estimating vehicle emissions simultaneously under each test drive-cycle. The major contribution of the thesis is to investigate the inter-correlations between vehicle emissions within a well controlled data set, and to test the hypothesis of vehicle emissions interdependencies. We find that HC, CO, and NOX are endogenously or jointly dependent in a system of simultaneous-equations. The results of the analysis demonstrate that there is strong evidence against the null hypothesis (H0) in favour of the alternative hypothesis (H1) that HC, CO, and NOX are statistically significantly interdependent. We find, for the thesis sample, that NOX and CO are negatively related, whereas HC and CO emissions are positively related, and HC and NOX are positively related. The results of the thesis yield new insights. They bridge a very important gap in the current knowledge on vehicle emissions. They advance not only our current knowledge that HC, CO, and NOX should be predicted jointly since they are produced jointly, but also acknowledge the appropriateness of using 3SLS regression for estimating vehicle emissions simultaneously. The thesis measures the responses of emissions to changes with respect to changes in the other emissions. We investigate emission responses to a one percent increase in an emission with respect to the other emissions. We find the relationship between CO and NOX is of special interest. After vehicles were tuned, we find those vehicles that exhibit a one percent increase in NOX exhibit simultaneously a 0.35 percent average decrease in CO. Similarly, we find that vehicles which exhibit a one percent increase in CO exhibit simultaneously a 0.22 percent average decrease in NOX. We find that the responses of emission to changes with respect to other emissions vary with various test drive-cycles. Nonetheless, a band of upper and lower limits contains these variations. After vehicle tuning, a one percent increase in HC is associated with an increase in NOX between 0.5 percent and 0.8 percent, and an increase in CO between 0.5 percent and one percent Also, for post-tuning vehicles, a one percent increase in CO is associated with an increase in HC between 0.4 percent and 0.9 percent, and a decrease in NOX between 0.07 percent and 0.32 percent. Moreover, a one percent increase in NOX is associated with increase in HC between 0.8 percent and 1.3 percent, and a decrease in CO between 0.02 percent and 0.7 percent. These measures of the responses are very important derivatives of the hypothesis investigated in the thesis. They estimate the impacts of traffic management schemes and vehicle operations that target reducing one emission, on the other non-targeted emissions. However, we must be cautious in extending the results of the thesis to the modern vehicles fleet. The modern fleet differs significantly in technology from the dataset that we use in this thesis. The dataset consists of measurements of HC, CO, and NOX emissions for 542 gasoline-fuelled passenger vehicles, under six test drive-cycles, before and after the vehicles were tuned. Nevertheless, the dataset has a number of limitations such as limited model year range, limited representations of modal operations, and limitations of the measurements of emissions based only on averages of test drive-cycles, in addition to the exclusion of high-emitter emission measurements from the dataset. The dataset has a limited model year range, i.e., between 1980 and 1991. We highlight the age of the dataset, and acknowledge that the present vehicle fleet varies technologically from the vehicles in the dataset used in this thesis. Furthermore, the dataset has a limited number of makes - Holden, Ford, Toyota, Nissan, and Mitsubishi. There are also a limited number of modal operations. The model operations presented in the dataset are cold start, warming-up, and hot stabilised driving conditions. However, enrichment episodes are not adequately presented in the test-drive cycles of the dataset. Moreover, the dataset does not take into account driving behaviour influences, and all measurements are cycle-based averages. The emission measurements of laboratory-based testings are aggregated over a test drive cycle, and the test drive-cycle represents an average trip over an average speed. The exclusion of the measurements of high emitting vehicles from the dataset introduces further limitations. Remote sensing studies show that 20 percent of the on-road vehicle fleet is responsible for 80 percent of HC and CO emissions. The findings of the thesis assist in the identification of the best strategies to mitigate the most adverse effects of air-pollution, such as the most severe pollution that have the most undesirable pollution effects. Also, they provide decision-makers with valuable information on how changes in the operation of the transport system influence the urban air-quality. Moreover, the thesis provides information on how vehicle emissions affect the chemistry of the atmosphere and degrade the urban air-quality.
323

Modelling vehicle emissions from an urban air-quality perspective:testing vehicle emissions interdependencies

Dabbas, Wafa M January 2010 (has links)
Doctor of Philosophy(PhD) / Abstract This thesis employs a statistical regression method to estimate models for testing the hypothesis of the thesis of vehicle emissions interdependencies. The thesis at the beginnings, reviews critically the formation of emissions in gasoline-fuelled engines, and also reviews existing and emerging models of automotive emissions. The thesis then, presents the relationships between the urban transport system and vehicle emissions. Particularly, it summarises different types of emissions and the contributory factors of the urban transport system to such emissions. Subsequently, the thesis presents the theory of vehicle emissions interdependencies and the empirical framework for testing the hypothesis of the thesis. The scope of testing the hypothesis of the thesis is only limited to gasoline-fuelled conventional vehicles in the urban transport environment. We use already available laboratory-based testing dataset of 542 passenger vehicles, to investigate the hypothesis of the thesis of vehicle emissions interdependencies. HC, CO, and NOX emissions were collected under six test drive-cycles, for each vehicle before and after vehicles were tuned. Prior to using any application, we transform the raw dataset into actionable information. We use three steps, namely conversion, cleaning, and screening, to process the data. We use classification and regression trees (CART) to narrow down the input number of variables in the models formulated for investigating the hypothesis of the thesis. We then, utilise initial results of the analysis to fix any remaining problems in the data. We employ three stage least squares (3SLS) regression to test the hypothesis of the thesis, and to estimate the maximum likelihood of vehicle variables and other emissions to influence HC, CO, and NOX emissions simultaneously. We estimate twelve models, each of which consists of a system of three simulations equations that accounts for the endogenous relations between HC, CO and NOX emissions when estimating vehicle emissions simultaneously under each test drive-cycle. The major contribution of the thesis is to investigate the inter-correlations between vehicle emissions within a well controlled data set, and to test the hypothesis of vehicle emissions interdependencies. We find that HC, CO, and NOX are endogenously or jointly dependent in a system of simultaneous-equations. The results of the analysis demonstrate that there is strong evidence against the null hypothesis (H0) in favour of the alternative hypothesis (H1) that HC, CO, and NOX are statistically significantly interdependent. We find, for the thesis sample, that NOX and CO are negatively related, whereas HC and CO emissions are positively related, and HC and NOX are positively related. The results of the thesis yield new insights. They bridge a very important gap in the current knowledge on vehicle emissions. They advance not only our current knowledge that HC, CO, and NOX should be predicted jointly since they are produced jointly, but also acknowledge the appropriateness of using 3SLS regression for estimating vehicle emissions simultaneously. The thesis measures the responses of emissions to changes with respect to changes in the other emissions. We investigate emission responses to a one percent increase in an emission with respect to the other emissions. We find the relationship between CO and NOX is of special interest. After vehicles were tuned, we find those vehicles that exhibit a one percent increase in NOX exhibit simultaneously a 0.35 percent average decrease in CO. Similarly, we find that vehicles which exhibit a one percent increase in CO exhibit simultaneously a 0.22 percent average decrease in NOX. We find that the responses of emission to changes with respect to other emissions vary with various test drive-cycles. Nonetheless, a band of upper and lower limits contains these variations. After vehicle tuning, a one percent increase in HC is associated with an increase in NOX between 0.5 percent and 0.8 percent, and an increase in CO between 0.5 percent and one percent Also, for post-tuning vehicles, a one percent increase in CO is associated with an increase in HC between 0.4 percent and 0.9 percent, and a decrease in NOX between 0.07 percent and 0.32 percent. Moreover, a one percent increase in NOX is associated with increase in HC between 0.8 percent and 1.3 percent, and a decrease in CO between 0.02 percent and 0.7 percent. These measures of the responses are very important derivatives of the hypothesis investigated in the thesis. They estimate the impacts of traffic management schemes and vehicle operations that target reducing one emission, on the other non-targeted emissions. However, we must be cautious in extending the results of the thesis to the modern vehicles fleet. The modern fleet differs significantly in technology from the dataset that we use in this thesis. The dataset consists of measurements of HC, CO, and NOX emissions for 542 gasoline-fuelled passenger vehicles, under six test drive-cycles, before and after the vehicles were tuned. Nevertheless, the dataset has a number of limitations such as limited model year range, limited representations of modal operations, and limitations of the measurements of emissions based only on averages of test drive-cycles, in addition to the exclusion of high-emitter emission measurements from the dataset. The dataset has a limited model year range, i.e., between 1980 and 1991. We highlight the age of the dataset, and acknowledge that the present vehicle fleet varies technologically from the vehicles in the dataset used in this thesis. Furthermore, the dataset has a limited number of makes - Holden, Ford, Toyota, Nissan, and Mitsubishi. There are also a limited number of modal operations. The model operations presented in the dataset are cold start, warming-up, and hot stabilised driving conditions. However, enrichment episodes are not adequately presented in the test-drive cycles of the dataset. Moreover, the dataset does not take into account driving behaviour influences, and all measurements are cycle-based averages. The emission measurements of laboratory-based testings are aggregated over a test drive cycle, and the test drive-cycle represents an average trip over an average speed. The exclusion of the measurements of high emitting vehicles from the dataset introduces further limitations. Remote sensing studies show that 20 percent of the on-road vehicle fleet is responsible for 80 percent of HC and CO emissions. The findings of the thesis assist in the identification of the best strategies to mitigate the most adverse effects of air-pollution, such as the most severe pollution that have the most undesirable pollution effects. Also, they provide decision-makers with valuable information on how changes in the operation of the transport system influence the urban air-quality. Moreover, the thesis provides information on how vehicle emissions affect the chemistry of the atmosphere and degrade the urban air-quality.
324

Estudo das demandas de etanol e gasolina no Brasil no período 2001-2009

Souza, Alberto de Nes de 07 February 2011 (has links)
Submitted by Cristiane Oliveira (cristiane.oliveira@fgv.br) on 2011-06-03T16:56:50Z No. of bitstreams: 1 66080100274.pdf: 1517139 bytes, checksum: 14aa5d4963f1c54e4540e594fbf636af (MD5) / Approved for entry into archive by Suzinei Teles Garcia Garcia(suzinei.garcia@fgv.br) on 2011-06-03T17:03:24Z (GMT) No. of bitstreams: 1 66080100274.pdf: 1517139 bytes, checksum: 14aa5d4963f1c54e4540e594fbf636af (MD5) / Approved for entry into archive by Vera Lúcia Mourão(vera.mourao@fgv.br) on 2011-06-03T17:07:41Z (GMT) No. of bitstreams: 1 66080100274.pdf: 1517139 bytes, checksum: 14aa5d4963f1c54e4540e594fbf636af (MD5) / Made available in DSpace on 2011-06-03T17:09:59Z (GMT). No. of bitstreams: 1 66080100274.pdf: 1517139 bytes, checksum: 14aa5d4963f1c54e4540e594fbf636af (MD5) Previous issue date: 2011-02-07 / Gasoline and ethanol are the main fuels for cars and light commercials in Brazil and the study of demand for these products provides important indicators about consumer behavior. There are many researches estimating the price and income elasticities of gasoline and few studies trying the same for ethanol. This dissertation makes such a study, taking into account the specific characteristics of the fuel market in Brazil and, in some extent, contributing to past research. An econometric analysis was conducted in two stages with monthly data from the ANP to the units of Brazil, using the tools to control for the endogeneity in demand analysis. In addition, we took into consideration the fact that not all states have on ethanol-gasoline price in the range near the critical value of 70%, which may complicate the measurement of price elasticities in these regions. Thus, the states whose relative price of ethanol-gasoline is usually in the range far from the critical value of 70% were analyzed separately. Finally, as the analysis was done separately for two different periods, it is expected that the growing fleet of vehicles with flex-fuel engines change consumer behavior. The regression results confirm an increase in price elasticities (own and cross) of gasoline and ethanol in Brazil. However, it was not confirmed the hypothesis that the estimated elasticities would be larger in states close to parity. Additionally, the estimates suggest that in the most recent period ethanol presented in module price elasticity significantly greater than gasoline. / A gasolina e o etanol são os principais combustíveis para veículos leves no Brasil e o estudo da sua demanda fornece importantes indicadores a respeito do comportamento dos consumidores. Vários pesquisadores no mundo tentaram estimar as elasticidades de preço e renda da gasolina e em menor número do etanol. Esta dissertação faz um estudo desse tipo, levando em consideração as características específicas do mercado de combustíveis no Brasil e contribuindo em alguns pontos em relação às pesquisas realizadas anteriormente. Um estudo econométrico em dois estágios foi realizado com dados mensais da ANP para as unidades federativas do Brasil, utilizando variáveis instrumentais para controlar a endogeneidade na análise da demanda. Além disso, levou-se em consideração o fato de que nem todos os estados brasileiros têm preço relativo etanol-gasolina numa faixa próxima ao valor crítico de 70%, o que pode dificultar a mensuração das elasticidades-preço nessas regiões. Assim sendo, os estados cujo preço relativo álcool-gasolina costuma estar numa faixa distante do valor crítico de 70% foram analisados separadamente. Por fim, a análise foi feita separadamente para dois períodos distintos, pois é esperado que o crescimento da frota de veículos com motores flex-fuel altere o comportamento dos consumidores. Os resultados das regressões confirmam um aumento das elasticidades-preço própria e cruzada do consumo de gasolina e etanol no Brasil. Contudo, não foi confirmada a hipótese de que as elasticidades estimadas seriam maiores nos estados próximos a paridade. Adicionalmente, as estimações sugerem que no período mais recente o etanol apresenta em módulo uma elasticidade-preço significativamente maior que a gasolina.
325

Estudo dos principais precursores de ozônio na região metropolitana de São Paulo / Study of major precursors ozone in the metropolitan area of São Paulo

ALVIM, DEBORA S. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:41:58Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:38Z (GMT). No. of bitstreams: 0 / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
326

Desempenho de um ve?culo flex em bancada dinamom?trica de chassi

Laranja, Gil Colona 18 December 2010 (has links)
Made available in DSpace on 2014-12-17T14:58:06Z (GMT). No. of bitstreams: 1 GilCL_DISSERT.pdf: 1771464 bytes, checksum: 92ddc93639f74d5c2bbc96617815f7ed (MD5) Previous issue date: 2010-12-18 / Flex-fuel vehicles are equipped with Otto Cycle internal combustion engines and have the capability of functioning with more than one type of fuel, mixed at the same tank and burned in the combustion chamber simultaneously. This sort of motorization is a world pattern due to the scarcity of petroleum, the trade of several types of fuels, technology advances and the restriction imposed to gas emissions to the atmosphere. In Brazil, the Flexfuel vehicles are a reality, specially the ones using fuel with 20 to 25% anhydrous alcohol mixed with gasoline and those that use natural gas or original liquid fuel (gasoline or hydrated ethanol). The Brazilian model Fiat Siena, the object of this present scientific investigation, is equipped with a unique electronic central capable of managing the liquid or gaseous fuels. The purpose of this research was to perform a comparative analysis in terms of performance (in terms of both potency and consumption) of a tetra-fuel vehicle - using a chassis dynamometer, operating with different fuels: common gasoline, premium gasoline, Podium gasoline, ethanol or natural gas. It became necessary to develop a bench of tests and trials procedures, as well as to know the functioning of the electronic management of the vehicle under analysis. The experiments were performed at the automotive laboratory in CTGAS-ER (Center of Gas Technologies and Renewable energies) at the light of Brazilian standard ABNT, NBR 7024: Light on-road vehicles - measurement of fuel consumption. The essay results on specific fuel consumption using common gasoline, premium gasoline and Podium gasoline have shown similar results, both for urban and road driving cycles / Os ve?culos flex s?o equipados com um motor de combust?o interna do ciclo Otto e t?m como caracter?stica a capacidade de funcionar com mais de um tipo de combust?vel, misturados no mesmo tanque e queimados na c?mara de combust?o simultaneamente. Este tipo de motoriza??o ? uma tend?ncia mundial devido ? escassez do petr?leo, a comercializa??o de v?rios tipos de combust?veis, aos avan?os tecnol?gicos dos sistemas de gerenciamento eletr?nico de combust?vel e ?s restri??es as emiss?es de gases poluentes na atmosfera. No Brasil, os ve?culos flex s?o uma realidade, com destaque para os ve?culos alimentados com 20 a 25% do ?lcool anidro misturado com gasolina e os que utilizam g?s natural ou o combust?vel l?quido original (gasolina ou etanol hidratado). O FIAT SIENA TETRAFUEL, objeto da presente investiga??o, ? equipado com uma ?nica central eletr?nica capaz de gerenciar os combust?veis l?quidos ou gasoso. A pesquisa em tela teve como prop?sito a an?lise comparativa de desempenho (pot?ncia e consumo) de um ve?culo tetracombust?vel simulando ciclos de condu??o urbano e de estrada em um dinam?metro de chassi, operando com os combust?veis: gasolina comum (tipo C), gasolina aditivada (tipo C), gasolina Podium (Premium), etanol (AEHC) ou g?s natural (GNV). Foi necess?rio desenvolver bancada de testes e procedimentos de ensaios, como tamb?m conhecer o funcionamento do gerenciamento eletr?nico do ve?culo em quest?o. Os ensaios foram realizados no Laborat?rio do Centro de Tecnologias do G?s e Energias Renov?veis de acordo com a norma ABNT NBR 7024 - Ve?culos rodovi?rios leves Medi??o do consumo de combust?vel. Os resultados dos ensaios de consumo espec?fico com as gasolinas comum, aditivada e Podium resultaram em valores pr?ximos, tanto no ciclo de condu??o urbano como tamb?m no ciclo de condu??o de estrada
327

Degrada??o fotoqu?mica de hidrocarbonetos da gasolina em efluentes aquosos / Photochemical degradation of the gasoline of hydrocarbons in wastewaters

Silva, Douglas do Nascimento 10 October 2002 (has links)
Made available in DSpace on 2014-12-17T15:01:16Z (GMT). No. of bitstreams: 1 DouglasNS.pdf: 627007 bytes, checksum: b05193ec4ef1bbecaf4b2d739179e597 (MD5) Previous issue date: 2002-10-10 / Photo-oxidation processes of toxic organic compounds have been widely studied. This work seeks the application of the photo-Fenton process for the degradation of hydrocarbons in water. The gasoline found in the refinery, without additives and alcohol, was used as the model pollutant. The effects of the concentration of the following substances have been properly evaluated: hydrogen peroxide (100-200 mM), iron ions (0.5-1 mM) and sodium chloride (200 2000 ppm). The experiments were accomplished in reactor with UV lamp and in a falling film solar reactor. The photo-oxidation process was monitored by measurements of the absorption spectra, total organic carbon (TOC) and chemical oxygen demand (COD). Experimental results demonstrated that the photo-Fenton process is feasible for the treatment of wastewaters containing aliphatic hydrocarbons, inclusive in the presence of salts. These conditions are similar to the water produced by the petroleum fields, generated in the extraction and production of petroleum. A neural network model of process correlated well the observed data for the photooxidation process of hydrocarbons / Processos de fotooxida??o de compostos org?nicos t?xicos t?m sido bastante estudados. Este trabalho trata da aplica??o do processo foto-Fenton para a degrada??o de hidrocarbonetos em ?gua. A gasolina de refinaria, sem aditivos e ?lcool, foi usada como poluente modelo. O efeito das concentra??es dos seguintes compostos foi avaliado: per?xido de hidrog?nio (100-200mM), ?ons ferrosos (0,5-1,0mM) e cloreto de s?dio (200-2000ppm). Os experimentos foram realizados em um reator com l?mpada UV e em um reator solar tipo filme descendente. O processo de foto-oxida??o foi monitorado por medidas do espectro de absor??o, carbono org?nico total (TOC) e demanda qu?mica de oxig?nio (DQO). Os resultados experimentais demonstram que o processo foto-Fenton ? vi?vel para o tratamento de efluentes contendo hidrocarbonetos alif?ticos, inclusive na presen?a de sais, sob condi??es similares ?s das ?guas de produ??o de campos de petr?leo, geradas na extra??o e produ??o de petr?leo. Um modelo do processo, baseado em redes neurais, correlacionou bem os dados observados para o processo de fotooxida??o de hidrocarbonetos
328

Obten??o de novos derivados de ?-naftol e cardanol hidrogenado e avalia??o dos seus efeitos antioxidativos em gasolina automotiva

Dantas, Michelle Sinara Greg?rio 14 October 2005 (has links)
Made available in DSpace on 2014-12-17T15:01:57Z (GMT). No. of bitstreams: 1 MicheleSGD_tese.pdf: 2430121 bytes, checksum: 4479472ce6fc90295b8c785bc52f29fd (MD5) Previous issue date: 2005-10-14 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The chemical nature of the hidrocarbons found in gasoline directly affects the formation of oxidation complexes known as gums. Such complexes are slightly soluble in gasoline and their formation is delayed with the use of inhibitors, known as antioxidants. In this study, a synthetic compound (βnaphtol) and a natural subproduct (hydrogenated cardanol, derived from cashewnut shell liquid CNSL) have been used in order to generate novel antioxidant substances. These compounds were submitted to chemical reactions including alkylation, nitration and reduction, with the purpose of forming the following derivatives: 6(Nethyl,Nethylamino)βnaphtol (AO1); 6(Nethyl,Ndiethylamino)βnaphtol (AO2); aminoβnaphtol (AO3); 2(Nethyl,Nethylamino)pentadecylphenol (AOC1), 2(Nethyl,Ndiethylamino)pentadecylphenol (AOC2) and aminopentadecylphenol (AOC3). The derivatives were subjected to accelerated oxidative stability assays (Potential Gum and Induction Period) and to storage assays (Washed Gum and ASTM Color) during six months, with naphtha provided by the petroleum refinery RPBC (Refinaria Presidente Bernardes de Cubat?o, in Brazil). The results for the derivatives were compared to those for commercial additives [DBPC (2,6ditbutyl4methylpcresol) and PDA (N,N disecbutylpphenylenediamine)], which were also added to the naphtha produced at RPBC at the moment of sampling. From all tested antioxidants, the novel antioxidant AOC1 (derived from hydrogenated cardanol) yielded a better global performance. During the period of time in which the naphtha was stored, an examination of this material was carried out in parallel, using the mass spectrometry technique. This study allowed to monitor the formation of a triolefinic compound, as well as the observation of subsequent formation and rupture of the olefinic constituents. As an eventual result from these experimental investigations, a reaction route leading to gum formation has been suggested / O tipo de hidrocarboneto presente na gasolina influencia diretamente na forma??o de complexos de oxida??o conhecidos como goma. Estes complexos s?o levemente sol?veis em gasolinas e sua forma??o ? retardada atrav?s de uso de inibidor, conhecido como antioxidante. Neste estudo utilizouse um composto de origem sint?tica (βnaftol) e um subproduto natural (cardanol hidrogenado (derivado do l?quido da castanha de caju (LCC)) para obten??o de novas subst?ncias antioxidantes. Os compostos citados foram submetidos a rea??es qu?micas de alquila??o, nitra??o e redu??o para obten??o dos seguintes derivados : 6(Netil,Netilamino)βnaftol (AO1), 6(Netil,Ndietilamino)βnaftol (AO2), Aminoβnaftol (AO3), 2(Netil,Netilamino)pentadecilfenol (AOC1), 2(Netil,Ndietilamino)pentadecilfenol (AOC2) e Aminopentadecilfenol (AOC3). Os novos derivados foram submetidos a ensaios acelerados de estabilidade oxidativa (Goma Potencial e Per?odo de Indu??o) e a testes de estocagem (Goma Lavada e Cor ASTM) durante seis meses com nafta amostrada na RPBC (Refinaria Presidente Bernardes de Cubat?o). Os resultados com os novos derivados foram comparados ?queles obtidos com aditivos comerciais [DBPC (2,6diterbutil (4 metil)pcresol) e PDA (N,N disecbutilpfenilenodiamina)]que tamb?m foram adicionados ?s naftas da RPBC no momento da amostragem. O novo antioxidante AOC1(derivado do cardanol hidrogenado) apresentou melhor desempenho global dentre todos os antioxidantes amostrados. Durante o per?odo em que as naftas amostradas foram estocadas, foi realizado, em paralelo, um acompanhamento deste material atrav?s da t?cnica de Espectrometria de Massas e registrouse, n?o somente, a forma??o de um composto triolef?nico, como tamb?m acompanhouse as forma??es e as rupturas, subseq?entes, de compostos olef?nicos. Este acompanhamento possibilitou a sugest?o de uma rota reacional que leva ? forma??o de goma
329

Desgaste e corrosão de bombas de combustível com misturas de álcool e gasohol. / Wear and corrosion of fuel pumps with alcohol and gasohol fuel blends.

Fernando Fusco Rovai 04 March 2005 (has links)
O presente trabalho avalia o impacto da utilização de misturas de álcool e gasohol no desgaste e corrosão de bombas elétricas de combustível. / Assessement of alcohol and gasohol fuel blends impact on wear and corrosion of electric fuel pumps.
330

Estudo dos principais precursores de ozônio na região metropolitana de São Paulo / Study of major precursors ozone in the metropolitan area of São Paulo

ALVIM, DEBORA S. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:41:58Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:38Z (GMT). No. of bitstreams: 0 / O ozônio (O3) é um dos poluentes que representa grande preocupação em termos de qualidade do ar na Região Metropolitana de São Paulo (RMSP). No ano de 2012 foram observados 98 dias de ultrapassagens do padrão horário da qualidade do ar para este poluente na RMSP. A exposição aos poluentes atmosféricos como O3 e outros está associada ao prejuízo da saúde respiratória. O enfoque deste estudo é determinar os principais Compostos Orgânicos Voláteis (COV) precursores de O3 para auxiliar no controle deste poluente. Neste trabalho foram realizadas 78 amostragens durante a semana de hidrocarbonetos no ano de 2006 e 66 amostragens de hidrocarbonetos, 62 de aldeídos e 42 de etanol durante o ano de 2011/2012, 7:00 h às 9:00 h, na estação CETESB IPEN/USP. Medidas de COV também foram realizadas no ano de 2006 e 2008, na Estação CETESB Cerqueira César. Adicionalmente, foram efetuados testes de emissões veiculares durante o ano de 2009 de 5 veículos a diesel, 3 a etanol, 2 a gasolina C e 1 motocicleta. O modelo de trajetórias OZIPR foi utilizado para determinar os principais precursores de O3. Durante o ano de 2011/2012, na Estação CETESB IPEN/USP, a classe de aldeídos representou 35,3% dos COV analisados em concentração na atmosfera, seguido pelo etanol 22,6%, compostos aromáticos 15,7%, alcanos 13,5%, cetonas 6,8%, alcenos 6,0% e alcadienos < 0,1%. Considerando a concentração dos compostos e sua reatividade, as simulações executadas com o modelo OZIPR mostraram que o acetaldeído contribuiu com 61,2% da formação do O3 na atmosfera da RMSP no ano de 2011/2012. Dos COV analisados, a classe dos aldeídos contribui com 74% da produção de O3, aromáticos 14,5%, alcenos 10,2%, alcanos 1,3% e alcadienos (isopreno) 0,03%. O estudo de emissão veicular mostrou que 39% dos aldeídos foram provenientes de veículos a etanol, 28% a diesel, 26% a gasolina C e 7% de motocicletas. As emissões dos COV por veículos a gasolina contribuíram com 44% da formação de O3, a diesel 22%, a etanol 19% e motocicletas 15%. / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

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