Due to the continuous work in the automobile industry to reduce the environmental impact, reduce fuel consumption and increase efficiency, new technologies need to be developed and implemented in vehicles. For spark ignited engines, one technology that has received more attention in recent years is long route Exhaust Gas Recirculation (EGR), which means that exhaust gases after the turbine are transported back to the volume before the compressor in the air intake system of the engine. In this work, the components of the long route EGR system is modeled with mean value engine models in Simulink, and implemented in a existing Simulink engine model. Then different methods for estimating the mass flow over the long route EGR system are compared, and the transport delays for the recirculated exhaust gases in the engines air intake system are modeled. This work is based on measurements done on an engine rig, on which a long route EGR system was installed. Finally, some ideas on how a long route EGR system on a gasoline engine can be controlled are presented based on the results in this thesis work.

[pt] O derramamento no solo de poluentes imiscíveis com a água (NAPLs) devido a vazamentos de tanques de armazenamento ou dutos e acidentes de transporte é de grande interesse, pois o NAPL e/ou seus constituintes podem migrar através da zona vadosa até atingir o lençol freático e contaminar as fontes de água potável. No Brasil, a maioria dos postos de combustível e terminais de armazenamento possui tanques de etanol, gasolina misturada com etanol e óleo diesel. Um eventual derramamento ou vazamento de hidrocarbonetos derivados de petróleo, conhecidos como LNAPL, misturados com etanol tem um maior potencial de contaminação em função do efeito de co- solvência. A motivação deste trabalho é que muitos estudos têm sido realizados com principal interesse na zona saturada e pouco se sabe sobre o comportamento destes contaminantes na zona não saturada (McDowell e Powers, 2003 e Österreicher et al., 2007). Portanto, foram realizados ensaios de coluna com esferas de vidro com o objetivo de simular os vazamentos de hidrocarbonetos líquidos na superfície e comparar a massa de benzeno que fica retida no meio poroso em um vazamento de gasolina pura ou com etanol. Para avaliar estes ensaios em uma dimensão foi utilizado um programa disponível no sítio da Agência de Proteção Ambiental dos Estados Unidos (EPA) chamado Hydrocarbon Spill Screening Model (Weaver et al., 1994) e implementado um modelo para efetuar o balanço de massa e considerar o efeito de co-solvência em função da adição de etanol na gasolina comercial brasileira. Os resultados dos ensaios de laboratório foram comparados com os obtidos através do modelo supracitado e apresentaram uma aproximação satisfatória da previsão do comportamento do contaminante. / [en] The subsurface release of water immiscible pollutants (NAPLs) due to leaks in storage tanks or pipelines and spilling transportation accidents is of great concern, since the NAPL or its constituents may migrate through the vadose zone until reaching the water table and eventually contaminate clean water sources. In Brazil, most of the gas stations store ethanol, pure and gasoline blended ethanol, diesel, among others in tanks. A spill or leak of petroleum hydrocarbons, known as LNAPL (light Nonaqueous phase liquid), combined with ethanol has a major contamination potential associated to cosolvency effects. The motivation of this work is that many studies have been developed with special interest in the saturated zone and little is known about the behavior of these pollutants in the vadose zone (McDowell e Powers, 2003 e Österreicher et al., 2007). Thus, one dimensional column tests were performed in a glass porous media to simulate the spill of hydrocarbons in the subsurface and compare the retained mass of benzene in the porous media after a release of a pure or ethanol blended gasoline. In order to evaluate these 1D tests results, the Hydrocarbon Spill Screening Model - HSSM (Weaver et al., 1994) was used. This program can be found in the Environmental Protection Agency (EPA) website. A model was also implemented to consider the cosolvency effects in function of the ethanol addition in Brazilian`s commercial gasoline. The laboratory`s results were compared with the ones obtained by the model mentioned above and showed a satisfactory approximation for the prediction of the contaminant behavior.

This thesis is treating the modelling of a thermocouple (tc) to compensate forheat transfers due to convection, radiation and conduction when performingtemperature measurements in an SI-engine. An experiment plan was developedwhich covered experiments in an stc-rig and on a 4-cylinder SI-engine. The measurementsin the stc-rig was mainly to develop the model, while the measurementsin the engine lab was mainly to examine the characteristics of the engineand evaluate the modelled tc.Measurements with an exposed thin tip tc in the stc-rig showed a symmetricaltemperature profile in the pipe. By examining how the 1.5 mm tc behaved inthis environment with known gas temperature profile, the obtained knowledgecould be applied to cross-sectional measurements in the SI-engine. It was foundthat the temperature profile in the engine deviated from the temperature profilemeasured in the stc-rig. The temperature was higher near the top of the pipethan in the center and lower part. In the horizontal direction, the temperaturewas found to be constant.Conclusions drawn from measurements in the engine lab points to that the crosssectionaltemperature and mass flow profiles have a strong connection with theengine’s operation point. The cross-sectional profiles, along with respective profileover time, is crucial when estimating the energy content of an exhaust gaspulse.The inverted sensor model with optimized parameters could estimate the meanvalue of the measured gas temperature during stationary runs within 6 degC.

A abertura do setor sucroalcooleiro iniciou-se com a extinção do Instituto do Açúcar e do Álcool em 1990, que controlava as suas atividades desde 1933. A liberação dos preços da gasolina C ao consumidor se deu em 1996, generalizando a um processo de liberação no setor como um todo. O objetivo geral deste trabalho foi analisar e caracterizar o mercado de combustíveis, relacionando os efeitos de mudanças em variáveis associadas à oferta e demanda sobre o comportamento dos agentes num mercado parcialmente liberado, ou seja, entre os anos de 1995 e 2000. Os objetivos específicos foram estimar dois modelos: Modelo de Ajuste pelo Preço e Modelo de Ajuste pela Quantidade. O primeiro modelo foi composto por oito equações, sendo quatro delas de quantidades e quatro de preços dos combustíveis - gasolina C ao varejo e ao atacado, álcool anidro ao produtor e gasolina A na refinaria. O segundo modelo foi composto por cinco equações, sendo uma da quantidade de gasolina C do varejo e quatro dos preços dos combustíveis. Os métodos de estimação foram Mínimos Quadrados em Dois Estágios para o primeiro modelo e Mínimos Quadrados Ordinários para o segundo. A distinção entre dois modelos ocorreu devido ao fato de que o sistema de preços de mercado ainda não era eficaz em função do caráter de transição conferido ao período da pesquisa. Com o primeiro modelo verificou-se o grau em que as forças de mercado já operavam entre 1995 e 2000. Com o segundo, procurou-se retratar a dinâmica de ajustamento em um mercado no qual as quantidades ofertadas eram pré-determinadas e os preços se ajustavam a partir de condições previamente estabelecidas pelo governo para a comercialização nos setores sucroalcooleiro e de combustíveis.Com as estimativas do segundo modelo foram calculados os Multiplicadores de Impacto de Theil, possibilitando avaliar os efeitos sobre a qua ntidade e os preços dos combustíveis de choques nas variáveis exógenas do modelo. Os resultados do primeiro modelo permitiram concluir: (a) que os ajustes via preços foram pouco eficazes para influenciar alterações nas quantidades dos combustíveis; e (b) a existência de certa inércia nos movimentos de preços, típica dos sistemas de controle de preços como os que vinham prevalecendo na década de 1990. Com os resultados do segundo modelo, as principais conclusões foram: (a) as variações de demanda tendiam a ser atendidas sem grandes alterações nos preços da gasolina e dos seus componentes; (b) os ajustes de preços ao atacado da gasolina C e da gasolina A, ainda que moderados, eram repassados ao varejo parcialmente; (c) o governo tendia a absorver os choques externos de preços não os repassando imediatamente ao varejo e o varejo não repassava, na mesma proporção, ao consumidor final. Assim, os resultados da pesquisa refletiram setores ainda operando sob a égide do Estado, que controlava suas operações sem necessariamente atender à lógica econômica. À medida que os ajustes nos setores sucroalcooleiro e de combustíveis passarem a ser guiados pelos preços de mercado, alterações de demanda e oferta passarão a se refletir nos preços dos vários elos desses setores, possivelmente nos moldes do Modelo de Ajuste pelo Preço discutido nesta pesquisa. / The economic opening of the sugar-ethanol market was started with the extinction of the "Instituto do Açúcar e do Álcool" ( Sugar-Ethanol Institute ) in 1990, which controlled its activities since 1933. The deregulation of gasoline C prices to the consumer took place in 1996, generating the deregulation process in the sector as a whole. The general aim of this study was to analyze and characterize the fuel market, relating the change effects in associated variables to the supply and demand about the agents' behavior in a market partly deregulated, that is, between 1995 and 2000. The specific aims were to estimate two models: Price Adjustment and Quantity Adjustment Models. The first was made up of eight equations, being four of quantities and four of fuel prices - retail and wholesale gasoline C prices, anhydrous ethanol to producer and gasoline A at refineries. The second model was made up of five equations, being one of gasoline C to retailing and four of fuel prices. The estimating methods for the first model were Minimum Squares in Two Stages, whereas Ordinaries Minimum Squares were used for the second one. The distinction between the two models was made necessary due to the fact that the market price system was not efficient yet, because of the transitional condition during the time of the research was done. Through the first model it was checked the degree the market forces already operated between 1995 and 2000. Through the second one, it was attempted to show the dynamic of adjustments in a market, which the amounts offered were pre-determined and the prices adjusted themselves based on commercialization conditions to the sugar-ethanol and fuel sectors, previously established by the government. Based on the estimates from the second model, it was figured the Impact Multipliers of Theil, allowing to evaluate the effects over quantities and prices of shock fuels in exogenous variables of the model. Results of the first model allow to conclude: (a) that adjustments via prices were little efficient to influence changes in fuel amounts and; (b) the existence of a certain inertness of prices movements, typical of price control systems like the ones being practiced in the 1990's. Through the results of model two, the main conclusions were: (a) the demand variations tended to be met without major changes in the price of gasoline and its compounds; (b) the wholesale gasoline C and gasoline A at refineries prices adjustments, even moderated, were reposed partly to retailing; (c) the government had a tendency to absorve the external price shocks and did not repose immediately to retailing and the retailing did not repose, at the same extent, to the final consumer. Therefore, the research results reflected sectors still operating under State domain, which controlled their operations without necessarily meeting the economic logic. As the adjustments in the sugar-ethanol and fuel sectors start to be dictated by market prices and demand-supply changes, they will start to reflect on prices of the various links of this sector, possibly in the form of the Price Adjustment Model, discussed in this study.

[pt] Uma bancada experimental foi desenhada e desenvolvida para realizar ensaios experimentais de um motor de ciclo Diesel utilizando gasolina como combustível. O motor (originalmente de ciclo diesel) foi adequado com diferentes dispositivos para funcionar em modo HCCI. Estas modificações não afetaram as condições originais do motor, podendo em qualquer momento voltar ao modo diesel. A instrumentação inclui medição de: temperatura (gases de escapamento, entrada da carga de admissão, óleo lubrificante), pressão (entrada do ar de admissão, entrada da gasolina, câmara de combustão), torque, rotação, vazão de ar, vazão de combustível. O motor foi submetido a diversas condições de operação e parâmetros de controle para estudar e analisar os efeitos da rotação do motor, da relação ar-combustível e da temperatura da mistura (ar-gasolina) de entrada na combustão HCCI. Os resultados indicam que as variações na quantidade de combustível e na temperatura de admissão têm um efeito direto na combustão HCCI. Maiores temperaturas ou quantidades de combustível provocam um avanço da fase de ignição, que teria uma influência direta no início da combustão e nas máximas pressões no interior da câmara de combustão. Os resultados também indicam que, incrementando a quantidade de combustível e variando a temperatura de admissão, mais energia útil é gerada até atingir o limite da zona de detonação, obtendo os melhores resultados para a temperatura de 75 Graus C com uma eficiência térmica de 34,2 por cento na rotação de 1900 RPM. Pequenos ganhos na eficiência de combustão são traduzidos em economias significativas de energia, reduzindo também os níveis de poluição dos gases de escapamento. / [en] An experimental device was designed and developed to perform experimental tests of a Diesel cycle engine using gasoline as fuel. The engine (originally Diesel cycle) was adequated with different devices to operate in HCCI mode. These modifications did not affect the original conditions of the engine, making it able return to the diesel mode at any moment. The instrumentation included measurement of: temperature (exhaust gases, intake charge admission, lubricating oil), pressure (inlet ar admission, injector nozzle, combustion chamber), torque, engine speed, crankshaft angle, air flow and fuel rate. The engine was submitted to various operating conditions and control parameters to study and analyze the effects of the engine speed, the air-fuel ratio and the temperature of the mixture (air-gasoline) in the HCCI combustion. The results indicate that variations in the amount of fuel and the intake temperature have a direct effect on HCCI combustion. High temperatures or amounts of fuel cause an advanced ignition, which would have a direct influence on the combustion timing and in the maximum pressure inside the combustion chamber. The results also indicate that increasing the amount of fuel and varying the inlet temperature, more useful energy is generated until it reaches the zone of detonation, getting the best results for the temperature of 75 C Degrees with a thermal efficiency of 34,2 percent at 1900 RPM. Small gains in combustion efficiency are translated into significant energy savings, reducing also the pollution levels caused by exhaust gases.

[pt] Visando determinar os teores dos componentes relevantes e as propriedades físicas de gasolinas comerciais e sintéticas foram tomados espectros Raman de 60 gasolinas comerciais e 52 misturas sintéticas simulando gasolinas. Os espectros foram tomados em um espectrômetro Nicolet FT Raman 950. Os espectros brutos obtidos foram tratados para evitar a influência da variabilidade de potência do laser excitante sobre as intensidades das linhas Raman. As variáveis independentes (intensidades Raman ) e as variáveis dependentes (propriedades das gasolinas comerciais e misturas sintéticas ) foram centradas em torno da média e submetidas à regressão por mínimos quadrados parciais, visando ajustar modelos que permitissem predizer quantitativamente os teores de etanol, hidrocarbonetos saturados, insaturados e aromáticos além dos valores das propriedades MON, RON, densidade e pontos de ebulição inicial, final, a 10%, 50% e 90% das amostras em estudo. Os resultados obtidos mostraram a potencialidade da espectroscopia Raman, para o desenvolvimento de métodos confiáveis para a análise de diversas características das gasolinas estudadas. / [en] The aim of this work was to determine the contents of the more important components and physical properties of commercial gasolines and synthetic mixtures with known composition, prepared in the laboratory. The Raman spectra of 60 gasolines and 52 mixtures were acquired with a Nicolet 950 Fourier Transform Raman (FT-Raman) spectrometer. The raw spectra were treated to avoid the laser potency variability on Raman lines intensities. The independent variables (Raman intensities) and the dependent variables (gasolines and mixtures properties) were mean centered and models were fit by partial least square regression seeking to predict the contents of ethanol, saturated, unsaturated and aromatic hydrocarbons. Also properties as MON, RON, density and boiling point values were determined by this procedure. The final results showed the potential of Raman spectroscopy for analysis of several properties of gasolines.

Este trabalho busca apurar a existência de assimetria na transmissão dos preços dos combustíveis no atacado para o varejo no Estado de São Paulo. Desde a introdução dos veículos flex-fuel no mercado brasileiro em 2003, o consumidor pode optar por abastecer com a gasolina comum ou com o etanol hidratado, sendo a sua escolha influenciada pelas variações na relação dos preços desses combustíveis, o que evidencia a importância de um estudo para entender o comportamento desses preços. Para tal, medias mensais dos preços da gasolina comum e do etanol hidratado nos níveis de distribuição e revenda, referentes ao estado paulista, para o período de novembro de 2002 a abril de 2015 foram consideradas na condução da analise empírica, que compreende a estimação de Modelos de Correção de Erros. Os resultados indicam a presença de assimetria na transmissão dos preços de ambos os combustíveis do atacado para o varejo, contudo esta se manifesta somente no curto prazo. Ademais, constata-se no mercado de combustíveis a assimetria positiva, de modo que no curto prazo aumentos nos preços no atacado elevam com maior intensidade os preços ao consumidor, em comparação a decréscimos nos preços ao consumidor provocados por choques negativos nos preços de distribuição. Tal assimetria pode proceder de uma combinação entre as reações dos consumidores as futuras oscilações nos preços e a gestão de estoques por parte dos postos de combustíveis. / This work aims to determine the existence of asymmetry in the transmission of fuel prices in the wholesale to retail in the State of Sao Paulo. Since the introduction of flex-fuel vehicles in the Brazilian market in 2003, the consumer can choose to fill up with regular gasoline or hydrated ethanol, and your choice is influenced by variations in the relative prices of these fuels, which highlights the importance of a study to understand the behavior of these prices. To this end, monthly average of prices of regular gasoline and hydrated ethanol in the levels of distribution and resale, for the State of Sao Paulo, for the period November 2002 to April 2015 were considered in conducting empirical analysis, which includes the estimation of Error Correction Models. The results indicate the presence of asymmetry in transmission of price of both fuels of wholesale for retail, however it is manifested in the short term only. Moreover, it appears in the fuel market the positive asymmetry, so that in the short term increases in wholesale prices rise more strongly consumer prices compared to decreases in consumer prices caused by negative shocks in distribution prices. Such asymmetry can come from a combination of consumer reactions to future fluctuations in prices and inventory management by the fuel stations.

A abertura do setor sucroalcooleiro iniciou-se com a extinção do Instituto do Açúcar e do Álcool em 1990, que controlava as suas atividades desde 1933. A liberação dos preços da gasolina C ao consumidor se deu em 1996, generalizando a um processo de liberação no setor como um todo. O objetivo geral deste trabalho foi analisar e caracterizar o mercado de combustíveis, relacionando os efeitos de mudanças em variáveis associadas à oferta e demanda sobre o comportamento dos agentes num mercado parcialmente liberado, ou seja, entre os anos de 1995 e 2000. Os objetivos específicos foram estimar dois modelos: Modelo de Ajuste pelo Preço e Modelo de Ajuste pela Quantidade. O primeiro modelo foi composto por oito equações, sendo quatro delas de quantidades e quatro de preços dos combustíveis – gasolina C ao varejo e ao atacado, álcool anidro ao produtor e gasolina A na refinaria. O segundo modelo foi composto por cinco equações, sendo uma da quantidade de gasolina C do varejo e quatro dos preços dos combustíveis. Os métodos de estimação foram Mínimos Quadrados em Dois Estágios para o primeiro modelo e Mínimos Quadrados Ordinários para o segundo. A distinção entre dois modelos ocorreu devido ao fato de que o sistema de preços de mercado ainda não era eficaz em função do caráter de transição conferido ao período da pesquisa. Com o primeiro modelo verificou-se o grau em que as forças de mercado já operavam entre 1995 e 2000. Com o segundo, procurou-se retratar a dinâmica de ajustamento em um mercado no qual as quantidades ofertadas eram pré-determinadas e os preços se ajustavam a partir de condições previamente estabelecidas pelo governo para a comercialização nos setores sucroalcooleiro e de combustíveis.Com as estimativas do segundo modelo foram calculados os Multiplicadores de Impacto de Theil, possibilitando avaliar os efeitos sobre a qua ntidade e os preços dos combustíveis de choques nas variáveis exógenas do modelo. Os resultados do primeiro modelo permitiram concluir: (a) que os ajustes via preços foram pouco eficazes para influenciar alterações nas quantidades dos combustíveis; e (b) a existência de certa inércia nos movimentos de preços, típica dos sistemas de controle de preços como os que vinham prevalecendo na década de 1990. Com os resultados do segundo modelo, as principais conclusões foram: (a) as variações de demanda tendiam a ser atendidas sem grandes alterações nos preços da gasolina e dos seus componentes; (b) os ajustes de preços ao atacado da gasolina C e da gasolina A, ainda que moderados, eram repassados ao varejo parcialmente; (c) o governo tendia a absorver os choques externos de preços não os repassando imediatamente ao varejo e o varejo não repassava, na mesma proporção, ao consumidor final. Assim, os resultados da pesquisa refletiram setores ainda operando sob a égide do Estado, que controlava suas operações sem necessariamente atender à lógica econômica. À medida que os ajustes nos setores sucroalcooleiro e de combustíveis passarem a ser guiados pelos preços de mercado, alterações de demanda e oferta passarão a se refletir nos preços dos vários elos desses setores, possivelmente nos moldes do Modelo de Ajuste pelo Preço discutido nesta pesquisa. / The economic opening of the sugar-ethanol market was started with the extinction of the "Instituto do Açúcar e do Álcool" ( Sugar–Ethanol Institute ) in 1990, which controlled its activities since 1933. The deregulation of gasoline C prices to the consumer took place in 1996, generating the deregulation process in the sector as a whole. The general aim of this study was to analyze and characterize the fuel market, relating the change effects in associated variables to the supply and demand about the agents' behavior in a market partly deregulated, that is, between 1995 and 2000. The specific aims were to estimate two models: Price Adjustment and Quantity Adjustment Models. The first was made up of eight equations, being four of quantities and four of fuel prices – retail and wholesale gasoline C prices, anhydrous ethanol to producer and gasoline A at refineries. The second model was made up of five equations, being one of gasoline C to retailing and four of fuel prices. The estimating methods for the first model were Minimum Squares in Two Stages, whereas Ordinaries Minimum Squares were used for the second one. The distinction between the two models was made necessary due to the fact that the market price system was not efficient yet, because of the transitional condition during the time of the research was done. Through the first model it was checked the degree the market forces already operated between 1995 and 2000. Through the second one, it was attempted to show the dynamic of adjustments in a market, which the amounts offered were pre-determined and the prices adjusted themselves based on commercialization conditions to the sugar-ethanol and fuel sectors, previously established by the government. Based on the estimates from the second model, it was figured the Impact Multipliers of Theil, allowing to evaluate the effects over quantities and prices of shock fuels in exogenous variables of the model. Results of the first model allow to conclude: (a) that adjustments via prices were little efficient to influence changes in fuel amounts and; (b) the existence of a certain inertness of prices movements, typical of price control systems like the ones being practiced in the 1990's. Through the results of model two, the main conclusions were: (a) the demand variations tended to be met without major changes in the price of gasoline and its compounds; (b) the wholesale gasoline C and gasoline A at refineries prices adjustments, even moderated, were reposed partly to retailing; (c) the government had a tendency to absorve the external price shocks and did not repose immediately to retailing and the retailing did not repose, at the same extent, to the final consumer. Therefore, the research results reflected sectors still operating under State domain, which controlled their operations without necessarily meeting the economic logic. As the adjustments in the sugar-ethanol and fuel sectors start to be dictated by market prices and demand-supply changes, they will start to reflect on prices of the various links of this sector, possibly in the form of the Price Adjustment Model, discussed in this study.

Thesis (M.Sc (Chemistry)) --University of Limpopo, 2013 / Since their discovery in 1991, CNTs have shown extraordinary properties and as result, these materials are being investigated for several different applications. Synthesis and electrochemical application of CNTs for hydrogen storage provide new possibilities for replacement of gasoline use in vehicles due to its cost and negative environmental impact. The study investigated the metal nanoparticles modified multi-walled carbon nanotubes as possible storage material for hydrogen. Herein, carbon nanotubes were successfully synthesized by pyrolysis of iron (II) phthalocyanine under Ar/H2 reducing atmosphere at 900 oC for 30 min. The micro-structural information of the as-prepared carbon nanotubes was examined by Transmission electron microscopy (TEM). It was found that the prepared CNTs were multi-walled with iron particles impurities present on the surface. Synthesized MWCNTs were found to have open tips as shown by TEM images. These materials were purified and functionalized with acid groups as confirmed by Fourier transform infra-red spectroscopy (FTIR). A successful decoration of MWCNTs by Cu, CuO, Fe, Fe2O3, Ni and NiO nanoparticles was confirmed by Scanning electron miscroscopy (SEM) and Transmission electron microscopy (TEM). TEM images showed that metal nanoparticles and metal oxides were well dispersed on the surface of the MWCNTs. The chemical composition of the as-prepared MWCNTs was confirmed by XRD (showing the presence of metal impurities and amorphous carbon). Synthesized materials were applied in electrochemical techniques such as cyclic voltammetry, chronopotentiometry and controlled potential electrolysis. These techniques have shown that modification of glassy carbon bare electrode (GCE) with carbon nanotubes decorated with metal nanoparticles (Cu, Ni and Fe), improves the current density, charge-discharge voltages and discharge capacity for hydrogen storage (in a 6 M KOH aqueous electrolyte). It was shown that MWCNTs exhibit high conductivity, porosity and high surface area for hydrogen storage. The increase in discharge capacity was as follows: GCE < GCE-MWCNT < GCE-MWCNT-M (M = Cu, Ni, Fe and/or metal oxides). This confirmed a successful modification of GCE with MWCNTs and MWCNT-M (M = Cu, Ni, Fe and/or metal oxides). The maximum discharge capacity of 8 nAh/g was obtained by GCE-MWCNTs-Ni electrode, corresponding to an H/C value of 28.32 x 10 It was confirmed that both Ni loading and MWCNTs loading have an impact on the current response, charge-discharge voltages and discharge capacity. A maximum current density and discharge current was reached when a 4wt% nickel was loaded. A decrease in current density and discharge current was observed for nickel loading of higher than 4wt%. Thus suggests a possible decrease in surface area of the adsorbed material on the surface of the electrode for hydrogen storage. As more MWCNTs were added, a decrease in current density was observed. A 2wt% MWCNTs gave higher discharge current and this was possibly due to less hindrance on the surface of the electrode for hydrogen to diffuse. It was shown that calcining the metal nanoparticles result in particles agglomeration, as confirmed by Transmision electron microscopy (TEM). This resulted in a decrease in surface area of the working electrode. A low current response was observed compared to the uncalcined Ni nanoparticles. The highest exchange current density was obtained while using a GCE-MWCNT-Nical as compared to the GCE-MWCNT-Niuncal electrode. The applied discharge current in CPE was also shown to have influence on the discharge capacity. An increase in discharge capacity for the GCE-MWCNT-Ni (2wt% MWCNTs and 4wt% Ni) electrode was observed as more discharge current was applied. A decrease in discharge capacity for hydrogen was observed as more content of the MWCNT-Niuncal nanocomposite are added on the active surface area of the glassy carbon electrode.

Environmental pollution is an important problem of our world. Governments are aware of this problem and emission regulations are continuously improved. One of the strictest regulations is about unburned and burned hydrocarbon emissions. In internal combustion engines the origin of the burned and unburned hydrocarbons is fuel and engine oil. As a result of the sanctions and the necessity of improved combustion performance of the engine, manufacturers work on manufacturing technology and engine tribology. With the improvement of these areas oil loss from internal combustion engine is reduced. Engine oil consumption mechanisms are specific research areas in the internal combustion engine development. Oil consumption occurs via to two main routes: &ldquo / Valve train&rdquo / and &ldquo / in cylinder components&rdquo / . In cylinder components have three sub mechanisms: evaporation, ring scraping and blowback. In this thesis, blowback oil loss mechanism is studied. 2D flow model of piston-cylinder mechanism is developed in Fluent. Land pressures and ring end gap flow data are taken from this model. An iterative computer program is developed to calculate backflow oil consumption. In this program, an empirical entrainment correlation compiled from literature is used. The calculated oil consumption values match with the range of the values in the literature.