This thesis focuses on a technology called cylinder deactivation. The technology helps reducing emissions and fuel consumption. The first part summarizes the possibilities of application of the cylinder deactivation technology as well as advantages resulting from combination with other technologies. The thesis also consists of two design options for valvetrain in inline four-cylinder engine and the results of simulations of dynamics of its cranktrain.

Hypercholesterolemia is a dominant risk factor for a variety of cardiovascular diseases and involves a chronic inflammatory component in which neutrophil activity plays a critical role. Recently, fluid shear stress mechanotransduction has been established as a control mechanism that regulates the activity of neutrophils by reducing the formation of pseudopods and the surface expression of CD18 integrins, thereby rendering these cells rounded, deformable, and non-adhesive. This is critical for maintaining a healthy circulation, because chronically activated neutrophils not only release excess cytotoxic and degradative agents but also exhibit a reduced efficiency to pass through the small vessels of the microcirculation leading to increased microvascular resistance. We hypothesized that aberrant neutrophil mechanosensitivity to fluid shear stress due to the altered blood environment (i.e., excess plasma cholesterol) is a contributing factor for elevated hemodynamic resistance in the microcirculation associated with hypercholesterolemia. For this purpose, the present work firstly showed that the sensitivity of neutrophils to fluid shear stress depends on the cholesterol-dependent fluidity of the cell membrane, and that, in the face of hypercholesterolemia, the neutrophil mechanosensitivity highly correlated with the plasma levels of free cholesterol. The second part of this project demonstrated that, when subjected to shear stress fields, leukocyte suspensions exhibited transient (within 10 min of flow onset) time-dependent reductions in their apparent viscosity. Moreover, shear-induced changes in viscosity of cell suspensions were influenced by disturbances of membrane cholesterol and fluidity in a fashion similar to that for shear-induced pseudopod retraction. Finally, the third part of this work provided evidence that neutrophils played a role in hypercholesterolemia-related impairment of flow recovery response to transient ischemia. In conclusion, results of the current work provided the first evidence that cholesterol is an important component of the neutrophil mechanotransducing capacity and impaired neutrophil shear mechanotransduction may disturb the blood flow rheology, leading to elevations in the apparent viscosity as well as in the resistance. This cholesterol-linked perturbation may be a contributing factor for the pathologic microcirculation associated with hypercholesterolemia.

The 3-PG physiological/mensurational hybrid model is a useful forest management tool capable of producing accurate growth results across a number of parameterised species. The temperature data used in the model are the average maximum and minimum values for photosynthesis above the compensation point (Landsberg and Sands 2011). There is a minimum temperature below which positive net CO₂ exchange will not occur, a maximum temperature above which it will not occur and an optimum temperature at which it is maximised. These parameters are used in the 3-PG physiological model of forest production. However, a species’ photosynthetic response to short-term variation may differ from one season to another as species acclimate to temperatures over periods of a few weeks. In this study, acclimation responses of four species of eucalypt and Sequoia sempervirens to long-term temperatures were studied over a wide range of short-term temperature changes in order to identify the minimum, optimum and maximum temperatures of CO₂ assimilation for physiological/mensurational hybrid modelling, and also to identify the sites for which the species would be best suited. In order to achieve the aims of this study, a growth chamber experiment was established. Seedlings of four eucalypt species and Sequoia sempervirens were grown at base-line day/night temperatures of 30/16, 22/12 and 10/5ºC in controlled environment chambers for three months and leaf gas exchange measurements were made of the species at seven short-term temperature levels (5, 10, 15, 20, 25, 30 and 35ºC). The optimum and the maximum temperatures for net photosynthesis increased with an increase in base-line temperature for all species. The highest optimum temperature and net photosynthetic rates recorded were in plants grown at 30/16ºC and the lowest were in those grown at 10/5ºC. The maximum rate of net CO₂ assimilation increased with the temperature at which plants were grown partly because of acclimation in key photosynthetic processes in the Calvin cycle. Responses of maximal carboxylation rate (Vcmax) and also the maximal light-driven electron flux (Jmax) to short-term temperature change varied with base-line temperature for all species studied. Net photosynthesis and photosynthetic parameters measured did not vary significantly with effects of nitrogen, phosphorus and their interaction (p = 0.1468). The ratio of Jmax to Vcmax decreased with increasing leaf temperatures for all species (p < 0.001). These results indicate that the species studied will adapt to long-run changes in temperature, and the parameters obtained from these studies can be used for models that simulate the physiology and growth of the species.

A potential route for converting different carbon sources (coal, natural gas and biomass) into synthetic fuels is the transformation of these raw materials into synthesis gas (CO and H2), followed by a catalytic step which converts this gas into the desired fuels. The present thesis has focused on two catalytic steps: Fischer-Tropsch synthesis (FTS) and methanation. The Fischer-Tropsch synthesis serves to convert synthesis gas into liquid hydrocarbon-based fuels. Methanation serves instead to produce synthetic natural gas (SNG). Cobalt catalysts have been used in FTS while nickel catalysts have been used in methanation.             The catalyst lifetime is a parameter of critical importance both in FTS and methanation. The aim of this thesis was to investigate the deactivation causes of the cobalt and nickel catalysts in their respective reactions.             The resistance to carbonyl-induced sintering of nickel catalysts supported on different carriers (γ-Al2O3, SiO2, TiO2 and α-Al2O3) was studied. TiO2-supported nickel catalysts exhibited lower sintering rates than the other catalysts. The effect of the catalyst pellet size was also evaluated on γ-Al2O3-supported nickel catalysts. The use of large catalyst pellets gave considerably lower sintering rates. The resistance to carbon formation on the above-mentioned supported nickel catalysts was also evaluated. Once again, TiO2-supported nickel catalysts exhibited the lowest carbon formation rates. Finally, the effect of operating conditions on carbon formation and deactivation was studied using Ni/TiO2 catalysts. The use of higher H2/CO ratios and higher pressures reduced the carbon formation rate. Increasing the temperature from 280 °C to 340 °C favored carbon deposition. The addition of steam also reduced the carbon formation rate but accelerated catalyst deactivation.             The decline in activity of cobalt catalysts with increasing sulfur concentration was also assessed by ex situ poisoning of a cobalt catalyst. A deactivation model was proposed to predict the decline in activity as function of the sulfur coverage and the sulfur-to-cobalt active site ratio. The results also indicate that sulfur decreases the selectivity to long-chain hydrocarbons and olefins. / <p>QC 20160817</p>

A desativação de um empreendimento mineiro é uma etapa importante do planejamento de uma mina e o seu estudo tem a finalidade de reduzir ou eliminar o passivo ambiental após o fechamento de uma mina. Para isto, são necessárias ações e programas desenvolvidos durante a vida da mina, com a participação de todos os interessados. É também relevante a previsão dos gastos com recuperação e desativação na fase de viabilidade econômica por meio de índices confiáveis. Foram avaliadas três empresas com áreas desativadas: uma desativada totalmente, a outra com frente de lavra desativada e a terceira paralisada. Ficou evidente, neste trabalho, a falta de roteiros e normas na legislação ambiental para a preparação da desativação no início de uma mina. Esta falta induz o empreendedor a só se preocupar com a desativação e a preparação de um plano quando o fechamento da mina é iminente; neste momento, as empresas estão descapitalizadas e os custos com a recuperação serão elevados. Foram propostos, modelo de Plano de Desativação, a ser preparado na etapa de planejamento da mina, e um índice econômico que relaciona os custos de recuperação aos custos de produção da mina na fase de viabilidade econômica. / One of the most important stages in the mine planning is the closure of a mine. This study has the aim to minimize or eliminate the well-known environmental damage left after the closure of the mine site. In order to carry out the process of mine closure, some procedures and programs should be conducted during the mine life cycle, involving people who are interested in environment problems. It is also important, the previous calculation of the environmental cost and all the cost relate to the closure of the mine itself during the mine project by using reliable cost index. In this research, three different mining companies having abandoned areas were evaluated: the first being closed-down completely, the second one having an abandoned mining face and the third one was thoroughly paralyzed. It was demonstrated in this case-study that there aren't any procedures or specifications for mines closure which could be considered in beginning of the mining project. This lack of regulation and procedures related to mining closure makes mining company managers or mining company owners only take into consideration a closure mining plan in the final stage of the production when the mine site needs to be closed as soon as possible. However, at that stage, most mining companies are with lack of working capital and the cost of environment protection is very expensive. As result of this research, a Closure Mine Model was proposed, which should be prepared in the very beginning of the mining planning stage. It was also proposed an economic index that is related to the cost of environment protection to the mining production cost in the stage of the economical feasibility studies.

No mundo moderno a energia elétrica tem um papel fundamental; ela é a base do progresso e desenvolvimento mundial. O seu surgimento propiciou a melhora no saneamento, na saúde, no abastecimento de água e alimentos, na qualidade de vida e também fez surgir a sociedade capitalista e de consumo. A utilização do petróleo como fonte geradora de energia foi o impulso da revolução industrial e através dele foram desenvolvidos motores, geradores e máquinas que contribuíram para o progresso. Com isto veio também a emissão de gases (CO2, CO, SOX e NOX) e outras substâncias que agravaram o efeito estufa, o buraco na camada de ozônio e a chuva ácida alterando o equilíbrio do planeta. O desenvolvimento de outras formas de geração de energia provocou mudanças nos locais onde estas foram instaladas, impactando o meio ambiente. Este trabalho apresenta uma avaliação ambiental sobre as diferentes formas de geração de energia elétrica e os impactos ambientais pertinentes a cada uma delas. Inclui cinco formas de geração de energia elétrica: termelétrica, nuclear, hidrelétrica, eólica e solar. No tópico energia termelétrica apresenta-se a geologia do petróleo, a sua extração e beneficiamento. Mostra também a descoberta e o desenvolvimento da indústria petrolífera no mundo e no Brasil. Detalha o funcionamento de três tipos de centrais termelétricas: a carvão, a gás e a óleo. São relacionados os impactos ambientais comuns a elas e os característicos de cada tipo de usina. Assim como o decorrente da desativação de cada uma delas. É apresentado um pequeno histórico da energia nuclear, seu desenvolvimento no Brasil e no mundo, bem como o funcionamento de uma usina e os impactos causados durante a sua operação e seu descomissionamento. A história, o funcionamento e o avanço da energia hidrelétrica no Brasil, as grandes usinas e a sua relação com o meio ambiente, são mostrados juntamente com os impactos ambientais na sua implantação, operação e desativação. A energia eólica é mostrada desde a sua implantação e funcionamento até os impactos ambientais decorrentes do processo de geração de energia elétrica e da sua desativação. No caso da energia solar é apresentado o funcionamento dos painéis solares, a implantação da central e os impactos ambientais relacionados a utilização desta. Os impactos originados na sua desativação também são apresentados. Destacados os impactos ambientais para cada forma de geração de energia elétrica, estes são correlacionados e comparados pela área de implantação da usina, a capacidade de geração, a eficiência, a potência e o custo do kW. Não existe uma forma totalmente limpa de geração de energia elétrica. Existem, sim, formas que não emitem os gases responsáveis pelo efeito estufa. Assim, todas as formas de geração de energia são importantes para um país, ou seja, quanto mais diversificada for a matriz energética, melhor. / Electric energy has an important function in the modern world; it is fundamental for progress and development. The electricity discovery allowed improvements in several areas: health, water and food supply, quality of life and sanitary conditions, and contributed also to the establishment of the capitalist and consumption society. The use of oil as an energy generation source was the impulse for the industrial revolution and machines, motors and generators were developed contributing to the progress. This also brought the pollutant gases emission (CO2, CO, SOX and NOX) and other substances that had contributed to the greenhouse effect, the ozone hole and the acid rain, modifying the balance of the planet. The development and implementation of other forms of energy generation caused local changes, where they were installed, giving rise to environmental impacts. This work presents an evaluation about different forms of electrical energy generation and the environmental impacts relative to each one of them. Five forms of electric energy generation were considered: thermoelectric, nuclear, hydroelectric, wind and solar energy. The implementation and the development of the petroleum industry in the world and in Brazil are presented. The geology of the oil, its extraction and quality improvement, besides details of the functioning of three types of thermoelectric power plants - coal, gas and oil - are also discussed. The specific as well as the environmental impacts they have in common are highlighted. The impacts originated from the deactivation of each one of them are also pointed out. The discovery and the development of nuclear energy in Brazil and in the world as well as the functioning of a nuclear power plant, the impacts generated by its operation and decommissioning are presented. The history, functioning and development of hydroelectric energy generation in Brazil, characterized by the great plants, are related to environmental aspects The environmental impacts due to its implantation, operation and deactivation are also evinced. The wind power plant implantation and functioning and the environmental impacts involved in the process of electric energy generation and its deactivation are analyzed. The functioning of the solar panels, the implantation of the power plant and the environmental impacts related to the use of solar energy are discussed. The impacts resulting from the deactivation are also presented. Once outlined the environmental impacts from each form of electric energy generation, they were correlated and compared considering the area of the power plant implantation, the generation capacity, the efficiency, the power and the cost per kW. There is no totally clean form of electric energy generation. There is, however, generation without emission of gases responsible for the green house effect. Therefore, all forms of energy generation are important for a country; in other words, the best situation is the diversity of the energy matrix.

The catalytic combustion of methane in excess of O2 over Pd catalysts was studied on model catalysts, including polycrystalline palladium foil and palladium single crystals. The kinetics of this reaction could be measured at conditions not accessible to supported catalysts and, thus, the issues of structure sensitivity, mechanism, hysteresis on oxidation, and deactivation could be studied in detail. Methane oxidation on PdO was insensitive to the original metal surface structure which PdO grew from, with turnover rates in the range of 1.3-4.7 s-1 on (111), (100) and (110) single crystals at 160 Torr O2, 16 Torr CH-4, 1 Torr H2O and 598 K. Methane oxidation on Pd metal was also insensitive to the original surface structure, with the turnover rate in the range of 2.0-2.8 s-1 on the three single crystals at 2.3 Torr O2, 0.46 Torr CH4, 0.05 Torr H2O and 973 K. Since there is no support effect and the surface purity could be certified, these turnover rates for this reaction can be used as a benchmark. The turnover rate for methane oxidation was found to decrease 95% when PdO decomposed to Pd metal at 888 K, showing that PdO was more active than Pd metal for methane combustion at this temperature. Water inhibition to the reaction was not observed at a temperature above 813 K on both PdO and Pd metal, while it was observed at 598 K on PdO. The activation energy on PdO was 32 kJ mol-1 in the range of 783-873 K, while it was 125 kJ mol-1 in the range of 568-623 K. The activation energy on Pd metal was 125 kJ mol-1 in the range of 930-980 K. The change of reaction orders and activation energies suggests that the reaction mechanism is a function of temperature and palladium chemical states. We propose that adsorbed water, the most abundant surface intermediate at 598 K, was not present in significant quantities at temperatures above 783 K. This change in surface inhibition by water is the reason for lower activation energy at temperatures above 783 K. Interaction between the catalyst and support, or presence of impurities, is one of the factors for catalyst deactivation. The interaction between oxidized silicon and palladium was investigated on a polycrystalline palladium foil and on supported Pd/SiO2 catalysts. During methane oxidation, oxidized silicon covered the palladium oxide surface as observed by TEM on Pd/SiO2 catalysts and by XPS on palladium foil. On Pd foil, the source of silica was a silicon impurity, common on bulk metal samples. The migration of oxidized silicon onto PdO deactivated the catalysts by blocking the active sites for methane oxidation. Silicon oxide overlayers were also observed covering the Pd surface after reduction of Pd/SiO2 by H2 at 923 K.

No mundo moderno a energia elétrica tem um papel fundamental; ela é a base do progresso e desenvolvimento mundial. O seu surgimento propiciou a melhora no saneamento, na saúde, no abastecimento de água e alimentos, na qualidade de vida e também fez surgir a sociedade capitalista e de consumo. A utilização do petróleo como fonte geradora de energia foi o impulso da revolução industrial e através dele foram desenvolvidos motores, geradores e máquinas que contribuíram para o progresso. Com isto veio também a emissão de gases (CO2, CO, SOX e NOX) e outras substâncias que agravaram o efeito estufa, o buraco na camada de ozônio e a chuva ácida alterando o equilíbrio do planeta. O desenvolvimento de outras formas de geração de energia provocou mudanças nos locais onde estas foram instaladas, impactando o meio ambiente. Este trabalho apresenta uma avaliação ambiental sobre as diferentes formas de geração de energia elétrica e os impactos ambientais pertinentes a cada uma delas. Inclui cinco formas de geração de energia elétrica: termelétrica, nuclear, hidrelétrica, eólica e solar. No tópico energia termelétrica apresenta-se a geologia do petróleo, a sua extração e beneficiamento. Mostra também a descoberta e o desenvolvimento da indústria petrolífera no mundo e no Brasil. Detalha o funcionamento de três tipos de centrais termelétricas: a carvão, a gás e a óleo. São relacionados os impactos ambientais comuns a elas e os característicos de cada tipo de usina. Assim como o decorrente da desativação de cada uma delas. É apresentado um pequeno histórico da energia nuclear, seu desenvolvimento no Brasil e no mundo, bem como o funcionamento de uma usina e os impactos causados durante a sua operação e seu descomissionamento. A história, o funcionamento e o avanço da energia hidrelétrica no Brasil, as grandes usinas e a sua relação com o meio ambiente, são mostrados juntamente com os impactos ambientais na sua implantação, operação e desativação. A energia eólica é mostrada desde a sua implantação e funcionamento até os impactos ambientais decorrentes do processo de geração de energia elétrica e da sua desativação. No caso da energia solar é apresentado o funcionamento dos painéis solares, a implantação da central e os impactos ambientais relacionados a utilização desta. Os impactos originados na sua desativação também são apresentados. Destacados os impactos ambientais para cada forma de geração de energia elétrica, estes são correlacionados e comparados pela área de implantação da usina, a capacidade de geração, a eficiência, a potência e o custo do kW. Não existe uma forma totalmente limpa de geração de energia elétrica. Existem, sim, formas que não emitem os gases responsáveis pelo efeito estufa. Assim, todas as formas de geração de energia são importantes para um país, ou seja, quanto mais diversificada for a matriz energética, melhor. / Electric energy has an important function in the modern world; it is fundamental for progress and development. The electricity discovery allowed improvements in several areas: health, water and food supply, quality of life and sanitary conditions, and contributed also to the establishment of the capitalist and consumption society. The use of oil as an energy generation source was the impulse for the industrial revolution and machines, motors and generators were developed contributing to the progress. This also brought the pollutant gases emission (CO2, CO, SOX and NOX) and other substances that had contributed to the greenhouse effect, the ozone hole and the acid rain, modifying the balance of the planet. The development and implementation of other forms of energy generation caused local changes, where they were installed, giving rise to environmental impacts. This work presents an evaluation about different forms of electrical energy generation and the environmental impacts relative to each one of them. Five forms of electric energy generation were considered: thermoelectric, nuclear, hydroelectric, wind and solar energy. The implementation and the development of the petroleum industry in the world and in Brazil are presented. The geology of the oil, its extraction and quality improvement, besides details of the functioning of three types of thermoelectric power plants - coal, gas and oil - are also discussed. The specific as well as the environmental impacts they have in common are highlighted. The impacts originated from the deactivation of each one of them are also pointed out. The discovery and the development of nuclear energy in Brazil and in the world as well as the functioning of a nuclear power plant, the impacts generated by its operation and decommissioning are presented. The history, functioning and development of hydroelectric energy generation in Brazil, characterized by the great plants, are related to environmental aspects The environmental impacts due to its implantation, operation and deactivation are also evinced. The wind power plant implantation and functioning and the environmental impacts involved in the process of electric energy generation and its deactivation are analyzed. The functioning of the solar panels, the implantation of the power plant and the environmental impacts related to the use of solar energy are discussed. The impacts resulting from the deactivation are also presented. Once outlined the environmental impacts from each form of electric energy generation, they were correlated and compared considering the area of the power plant implantation, the generation capacity, the efficiency, the power and the cost per kW. There is no totally clean form of electric energy generation. There is, however, generation without emission of gases responsible for the green house effect. Therefore, all forms of energy generation are important for a country; in other words, the best situation is the diversity of the energy matrix.

In recent years exposure to endocrine-disrupting chemicals (EDCs) in humans and wildlife has become an increasing concern. These compounds have been found ubiquitously in the environment and are suspected to induce adverse effects on the health of aquatic organisms. The results of health effects due to EDCs are clearly presented in many aquatic organisms, such as the feminization of male fish and a near extinction of some species. No clear effects on human health have been documented at this time. The major sources of these contaminants in the environment are discharges from wastewater treatment plants (WWTP) and diffuse pollution. Conventional wastewater treatment processes are not designed to remove such emerging pollutants and removal efficiency depends on many factors, including treatment technology and pollutant species. Passage through WWTPs and changes due to treatment technologies lead to detection of minute concentrations of EDCs in water downstream from discharge points. In New Orleans, Louisiana, discharge from its East Bank WWTP is being considered for potential reuse for wetland restoration. Therefore, effluents must be treated adequately to prevent adverse effects on the natural biota. Since effluents from wastewater treatment plants using conventional technologies may prove potentially unsafe for the environment due to the presence of EDCs, improved and/or new treatment processes for removal of these contaminants are needed. Ferrate (Fe+6) is known as an alternative oxidant for the treatment of wastewater that can be used as an oxidizing, disinfectant, and/or coagulating agent. Because of its redox potential, ferrate has been used as a disinfection agent and has been reported as a tool for enhanced treatment to remove many micropollutants without producing undesirable disinfection byproducts in contrast to other disinfection processes. Recent research has noted the ability of ferrate to deactivate a wide range of EDCs present in wastewater effluents. The negative effect of effluent's soluble organic matter on ferrate has been reported and higher doses of ferrate may be needed to obtain desired effluent quality. This study found that aerobic biological treatment processes reduce more than half of EDCs in wastewater and that free chlorine disinfection increases estrogenic activity in discharged effluent. Higher organic content in wastewater results in increased ferrate demand. The optimum ferrate dosage to deactivate EDCs in lab scale is 6 ppm, and a dosage of 8 ppm is possibly the operational optimum dose. pH neutralization by concentrated sulfuric acid was not found to affect EDCs deactivation efficiency by ferrate when added at the end of designed contact time. Ferrate was observed to have a high oxidation rate in the first10 minutes after application into wastewater and then degraded to other iron states, such as iron III. Higher oxidation rates can be obtained when more organics are present in wastewater as TOC. Higher dosages required longer oxidation reaction times. Ferrate was observed to generate fewer disinfection byproducts as compared to chlorine. Haloacetic acids in ferrate-treated effluent are generated from organics in wastewater and reactions with residual hypochlorite from the incomplete ferrate synthesis process. The reduction of trihalomethanes may be related to EDCs deactivation by ferrate. Because this study was performed on a lab scale, assessment of onsite production and application of ferrate is required to determine the feasibility of the ferrate treatment process at a full-scale treatment plant and to optimize required dosage. / acase@tulane.edu

The photocatalytic oxidation of trichloroethylene (TCE), ethylene. ethane and toluene on TiO2, Pt/TiO2 and Ag/TiO2 were investigated in a dedicated reactor set-up operated at room temperature and ambient pressure condition. The gas phase experiments were carried out for both single and binary mixtures of these chemicals to identify the role of Pt and Ag metallisation in the photocatalytic oxidation of different contaminants. In a single contaminant system, the presence of Pt enhanced the oxidation of ethylene, ethane and toluene but detrimental to the oxidation of TCE. In the oxidation of ethylene, Pt enhanced the oxidation by acting as catalyst and as electron sink. However, in ethane oxidation, the enhancement was solely associated to the ability of Pt to act as electron sink. The detrimental effect observed in TCE oxidation was attributed to Pt and Cl interaction, which formed a persistent inorganic chlorine species decreasing the overall Pt/TiO2 photocatalyst performance. Interestingly, Ag did not show any significant effect to the oxidation of any single system degradation. In binary system degradation, where TCE and another organic compound either ethylene, ethane or toluene were degraded simultaneously, Pt always caused a detrimental effect due to its strong interaction with Cl. However, the presence of Ag and Cl gives a more synergetic effect. Ag was found to provide sites to temporarily trap chlorine radicals as AgCl. Under illumination, electrons transferred from Cl to Ag forming chlorine radicals that could react with the surface contaminant enhancing its breakdown and mineralization.