This thesis develops analytical and numerical solutions that predict behavior of Cupric-Chloride droplets undergoing spraying and drying processes. Cupric-Chloride (CuCl2) is present as molten salt and slurry within the Copper-Chlorine thermo-chemical cycle for generation of hydrogen. Utilizing low-grade heat from nuclear or industrial sources to assist drying of Cupric-Chloride can increase efficiency of the overall process. Analytical correlations for heat and mass transfer are developed and applied to the analysis of a solution of Cupric-Chloride, subject to various drying conditions. The study provides new information on effects of different concentrations of water in CuCl2 slurry drying at low air temperatures. / UOIT

The dye sensitized solar cell (DSSC) is a promising low-cost technology alternative to conventional solar cell in certain applications. A DSSC is a photo-electrochemical photovoltaic device, mainly composed of a working electrode, a dye sensitized semiconductor layer, an electrolyte and a counter electrode. Sunlight excites the dye, producing electrons and holes that can be transported by the semiconductor and electrolyte to the external circuit, converting the sunlight into an electrical current. A material that could be useful for DSSCs is the nanoscale cupric oxide, which can act as a p-type semiconductor and has interesting properties such as low thermal emittance and relatively good electrical properties. The goal of this project was to synthesize and characterize CuO nanoparticles using three different methods and look into each products potential use and efficiency in DSSCs. The particles were synthesized using two different solution based chemical precipitation methods and a flame spray pyrolysis method, yielding nanostructures with different compositions, structures and sizes ranging from ~20 to 1000 nm. The nanoparticle powder synthesized by the flame spray pyrolysis route was tested as semiconductor layer in the working electrode of the DSSC. Current-voltage measurements presented low solar conversion efficiencies with a reversed current, meaning that the cupric oxide cells did not work in a desirable way. Further studies of the cupric oxide synthesis and its suitability in DSSCs are needed to increases the future possibilities for gaining well working p-type DSSCs with higher efficiencies.

Objetivou-se avaliar a influência da monensina sódica sobre o acúmulo hepático de cobre em ovinos. Haja vista, que ionóforos podem alterar a absorção, disponibilidade e distribuição tecidual de minerais em muitos tecidos do organismo. Foram utilizados 24 ovinos mestiços das raças Santa Inês x Dorper com média de três meses de idade e peso medio de 30 kg ao início do experimento, que receberam dieta basal calculada em 2,75% do peso corpóreo, sendo 50% de concentrado comercial (7,13 ppm de Cu) e 50% de feno de capim coast-cross (3,72 ppm de Cu) e 10 gramas de sal mineral (5,9 ppm de Cu). Os cordeiros foram distribuídos em quatro grupos distintos, sendo: Controle apenas dieta basal; Monensina (Mon) - dieta basal e 30 ppm de monensina sódica; Cobre (Cu) - dieta basal acrescida de 10 mg/kg P.V./dia de cobre, na forma de sulfato de cobre pentahidratado; e grupo Monensina+Cobre (MonCu) - dieta basal acrescida de 10 mg/kg P.V./dia de cobre e 30 ppm de monensina sódica. O período experimental teve duração de 14 semanas. Foram coletadas amostras de figado e bile no início por biópsia, e ao final do experimento por necropsia, para determinação de minerais, assim como amostras semanais de sangue para avaliação bioquímica, hematológica e mineral. Foi realizada análise estatística por meio de fatorial 2x2 considerando como fatores a inclusão ou não de cobre e monensina na dieta. Somente um animal apresentou quadro clínico de intoxicação cúprica acumulativa. As concentrações de cobre no fígado no início do experimento variaram entre 243,8 e 345,4 ppm não havendo diferença entre os grupos experimentais. As concentrações médias e desvios-padrão em ppm do cobre hepático ao final do experimento foram 3.363 ± 576 para o grupo MonCu; 2560 ± 524 para o grupo Cu; 562 ± 168 para o grupo Mon e 253 ± 131 para o grupo Controle. Ao final do estudo a concentração de cobre hepático foi influenciada pela suplementação com cobre (P = 0,0001) e monensina (P = 0,0003). Os grupos suplementados com cobre tiveram redução dos teores de ferro hepático (P = 0,0287) e aumento das concentrações de cobre na bile. A avaliação bioquimica demonstrou elevação da atividade sérica da GGT e AST (P < 0,05) nos grupos Cu e MonCu a partir da décima primeira semana do experimento em relação aos grupos Controle e Mon. O aumento da atividade destas enzimas foram influenciadas pela suplementação de cobre (P = 0,0340), enquanto os grupos suplementados com monensina apresentaram menores valores de creatinina quinase. Os resultados obtidos permitem concluir que a monensina interfere positivamente com o acúmulo hepático de cobre sendo que a sumplentação deste aditivo pode predispor a quadros de intoxicações cúprica em ovinos. / The aim of this study was to verify if monensin can change the accumulation of cooper in the liver of sheep, in view of ionophores can alter the absorption, availability, tiissue distribution of many minerals in the body. Twenty four crossbred Dorper X Santa Inês lambs wiht mean age of 3 months and wheitgh 30 kg at the begining of trial recived a basal diete calculated by 2,75% of body wheigth of 50% concentrade (7,13 ppm of Cu) and 50% cost-cross hay (3,72 ppm of Cu) and 10 g of mineral salt (5,9 ppm of Cu). Lambs were randomly distributed in four groups: Control: basal diet, Mon Group reciving basal diet plus 30 mg of monensin; Cu group: basal diet plus 10 mg Cu B.W of CuSO4.5H2O solution; Group CuMon: basal diet plus 30 mg of monensin and 10 mg of Cu B.W. The exeperimental period lasted for fourteen weeks. Liver samples were obtined by liver biopsy initially and at the end by necropsy when lambs were slaughterd. Blood samples were obtained weekly for determination of biochemical, hematological and mineral. Statistical analysis using a 2x2 factorial was conducted considering the factors copper and monensin in the diet and the interaction between them to evaluate the hepatic copper at the beginning and at the end of the study. Only one of animal of group MonCu exhibit clinical sings of copper toxicosis. Copper concentrations in the liver at the beginning of the experiment ranged between 243,8 and 345,4 ppm with no difference between experimental groups. Mean concentrations and standard deviations in ppm of hepatic copper at the end of the experiment were 3,363 ± 576 for MonCu group; 2560 ± 524 for Cu group; 562 ± 168 for the Mon group and 2538 ± 131 for the control group. At the end of the study liver concentrations and total hepatic copper accumulation were influenced both by the amount of dietary copper (P = 0.0001) and of monensin (P = 0.0003). The groups supplemented with copper had reduced levels of hepatic iron (P = 0.0287) and increased concentrations of copper in the bile. The biochemical evaluation demonstrated elevated serum AST and GGT activity (P <0.05) with Cu and MonCu from the eleventh week of the experiment compared to the control groups and Mon. The increased activity of these enzymes were influenced by copper supplementation (P = 0.0340), while group monensin had lower values of creatinine kinase. The results indicate that monensin interferes positively with hepatic copper accumulation and supplementation of this additive can predispose cupric poisoning in sheep.

This diploma thesis deals with the study of non-stationary diffusion of cupric ions in humic gels. The main objective of the work was the optimalization of conditions for using the electrochemical analyzer EcaFlow 150 GLP for the study of diffusion experiments. Next part was focused on reaching of constant concentration profiles of cupric ions in humic gel. Last aim of the study was the bond strength between cupric ions and humic acids. Diffusion was characterized by the values of the diffusion flux and cupric ions concentration profiles in humic gel. The data necessary for calculation were obtained by the electrochemical analyses of the extracts of each slice after diffusion on the EcaFlow 150 GLP. It has been proved that after application of several adjustment is this method suitable for the study of diffusion experiments. By using of different extraction agents was obtained the fractionalization of cupric ions according to the bond strength to humic acids.

Since the beginning of the Industrial Revolution, the global energy consumption has been continuously increasing, supplied mainly by coal, oil and natural gases. Unfortunately, this consumption is linked to the emission of greenhouse gasses such as CO2 to the atmosphere. For this reason, it is extremely important to look for sustainable and renewable energy sources in order to replace the commonly used fossil fuels. Within the different types of renewable energy sources, solar energy holds by far the largest potential capacity. In this respect, artificial photosynthesis is a promising technology not only to harvest solar energy, but also as a means of storage by producing energy-rich chemical fuels such as H2 from water. The main components of photoelectrochemical water splitting devices are the semiconductor light absorber photoelectrodes and the electrolyte. Chapter 1 reviews the fundamental aspects of photoelectrochemical water splitting and overviews the physics and electrochemistry of semiconductor materials. The second chapter describes the methodologies and techniques employed throughout the thesis. The experimental results are reported from Chapter 3 to 8, focusing on the development and further optimization of two photoelectrodes, concretely hematite and cupric oxide, besides the design and fabrication of tandem cells for standalone water splitting. In the case of hematite photoanodes, the main efforts have focused on its doping to enhance carrier density and mobility as a way of diminishing recombination. The major drawback present in cupric oxide photoelectrodes is their instability against photocorrosion, for this reason, research has focused on protecting them, both by impregnation and adsorption methodologies. Finally, a tandem cell composed by a hematite photoanode and a cupric oxide photocathode was developed. It is worth noting that a polymer electrolyte membrane (PEM) was employed as to facilitate upscaling and diminish the corrosion observed employing the typical acidic or basic liquid electrolytes.

Organic methods development has long dictated the molecular scaffolds available to the pharmaceutical and fine chemical synthesis industries. Photoredox catalysis has emerged as a powerful platform to enable novel reactivity with visible light irradiation through triplet sensitization and single-electron transfer. New methods involving radical intermediates are now readily accessible from countless starting materials through the application of these catalysts. Much of my work has utilized established photoredox platforms to enable both nickel catalyzed remote cross-coupling of primary amines via 1,5 hydrogen-atom transfer (HAT) and formal [3+2] synthesis of γ-lactams through triplet sensitization. My further work focuses on the application of ligand-to-metal charge transfer catalysis with cupric chloride and ferric chloride salts towards the alkylation of alkanes through the catalytic generation of chlorine radical to enable HAT. These studies expand photoredox catalysis to inner sphere mechanisms with abundant base-metal salts to enable redox chemistry at reduced electrochemical potentials.

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Formation of hexagonal boron nitride (h-BN) by carbothermic reduction of B2O3 under nitrogen atmosphere at 1500oC was investigated. Reaction products were subjected to powder X-ray diffraction analysis, chemical analysis and were examined by SEM. B4C was found to exist in the reaction products of the experiments in which h-BN formation was not complete. One of the aims of this study was to investigate the role of B4C in the carbothermic production of h-BN. For this purpose, conversion reaction of B4C into h-BN was studied. B4C used in these experiments was produced in the same conditions that h-BN was formed, but under argon atmosphere. It was found that formation of h-BN from B4C&ndash / B2O3 mixtures was slower than activated C&ndash / B2O3 mixtures. It was concluded that B4C is not a necessary intermediate product in the carbothermic production of h-BN. Some additives are known to catalytically affect the h-BN formation. The second aim of this study was to examine the catalytic effect of some alkaline earth metal oxides and carbonates, some transition metal oxides and cupric nitrate. It was found that addition of 10wt% CaCO3 into the B2O3+C mixture was optimum for increasing the rate and yield of h-BN formation and decreasing the B4C amount in the products and that the reaction was complete in 2 hours. CaCO3 was observed to be effective in increasing the rate and grain size of the formed h-BN. Addition of cupric nitrate together with CaCO3 provided a further increase in the size of the h-BN grains.