My main subject is to set up a measuring system of TEP(Thermoelectric Power) which the theory was based on Thomas Seebeck effect, mechanism of the translation between thermal energy and electricity. There are two applications of thermoelectric power. One is temperature dependent measurement which is applied on thermal couple sensor; another one is to study the thermoelectric materials. The Seebeck coeifficient is approached to zero when superconductivity was occurred, also the calibration of the obtained value and offers essential information of carriers. The hardware of thermoelectric power measuring system consists of Digital NanoVoltmeter¡BProgrammable current Source¡BTemperature controller and Cryogenic compressor system. In the software, we use LabView to control the integral system and analyze the obtained data. For the whole system, it is vital to find a suitable compositions of sample holder¡Bheater and pasted way of sample.

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Since discovering the anomaly of the La-based cuprates (La2-xSrxCuO4) at x~ , researches of stripe phase have been prevailing recently. Related vast experiments, like neutron scattering, Raman and infrared ray (IR) spectra, Hall effect, and magnetic susceptibility etc. have performed on this subject. These results indicate that a crossover from one- to two-dimensional charge transport happens at x~ . In this thesis, we synthesize p-type superconductors La2-xSrxCu0.995Zn0.005O4 by solid-state reaction. It has been well know there is a marked drop in Tc- x phase diagram at x~ of La2-xSrxCuO4. It is possible that this phenomenon is related to the formation of a stripe phase. The experimental work on x-ray absorption near edge spectroscopy (XANES) in La2-xSrxCuO4 and La2-x-ySrxNdyCuO4 have been done during these years in our laboratory. The results show that the absorption-spectroscopy diagrams of two systems have apparent differences in the region of upper Hubbard Band (UHB). The differences are due to that the stripe is observed in La2-x-ySrxNdyCuO4, but not in La2-xSrxCuO4. No observation of stripe phase in La2-xSrxCuO4 may be attributed to that the drop at x~ in Tc-x phase diagram of La2-xSrxCuO4 is smaller than that in La2-x-ySrxNdyCuO4. Therefore, thesis reports the comparison of spectroscopic diagram between La2-x-ySrxNdyCuO4 and La2-xSrxCu0.995Zn0.005O4, which show more a pronounced Tc-x drop than the La2-xSrxCuO4 system. Meanwhile, the effect on the thermoelectric power by the formation of stripe phase is also investigated and discussed as well.

Neste trabalho foram estudadas deposições químicas de ligas CuNixPy e foram fabricados termopares Cu/CuNixPy sobre superfícies de lâminas de silício. Inicialmente, as superfícies foram pré-ativadas em uma solução diluída de ácido fluorídrico contendo PdCl2. Em seguida, foi empregado um banho químico alcalino diluído em água deionizada contendo 15 g/l NiSO4.6H2O; 0,1 a 0,3 g/l CuSO4.5H2O; 15 g/l Na2HPO2.H2O e 60 g/l Na3C6H5O7.2H2O na temperatura de 80OC sendo que NH4OH foi adicionado até que o pH do banho atingisse o valor de 8,0. Verificamos que a concentração do sal de cobre na solução de deposição afeta substancialmente a quantidade de cobre nos depósitos de CuNixPy. As concentrações planares e as composições dos filmes depositados foram obtidas através da técnica de espectrometria de retroespalhamento de Rutherford (RBS) e a morfologia superficial foi caracterizada através da técnica de microscopia de força atômica (AFM). A solução: 15 g/l NiSO4.6H2O + 0,3 g/l CuSO4.5H2O + 15 g/l Na2HPO2.H2O + 60 g/l Na3C6H5O7.2H2O + NH4OH (pH 8.0) na temperatura de 80OC foi a escolhida na obtenção da liga CuNiP0,5 para a construção de termopares Cu/CuNiP0,5 os quais apresentaram potência termoelétrica de aproximadamente (866) V/oC semelhante aos valores típicos apresentados na literatura para Cu/CuNi. / In this work, it was studied chemical depositions of CuNixPy alloys and it was fabricated Cu/CuNixPy thermocouples onto silicon wafer surfaces. Initially, surfaces were pre-activated in a diluted hydrofluoric acid solution containing PdCl2. Following, it was used a de-ionizedwater- diluted alkaline chemical bath containing 15 g/l NiSO4.6H2O; 0,1-0,3 g/l CuSO4.5H2O; 15 g/l Na2HPO2.H2O and 60 g/l Na3C6H5O7.2H2O at temperature of 80OC where NH4OH was added until ph was 8.0. The concentration of copper salt in the deposition solution greatly affected the Cu content of the CuNixPy deposits. Areal concentration and composition were measured by Rutherford Backscattering Spectrometry (RBS) and surface morphology was characterized by Atomic Force Microscopy (AFM). The solution: 15 g/l NiSO4.6H2O; 0.3 g/l CuSO4.5H2O; 15 g/l Na2HPO2.H2O; 60 g/l Na3C6H5O7.2H2O; NH4OH (pH 8.0) at the temperature of 80OC was chosen to obtain the CuNiP0.5 alloy to fabricate Cu/CuNiP0.5 thermocouples with thermoelectric power of about (866) V/oC, which is similar to the typical values reported in literature for Cu/CuNi.

Neste trabalho foram estudadas deposições químicas de ligas CuNixPy e foram fabricados termopares Cu/CuNixPy sobre superfícies de lâminas de silício. Inicialmente, as superfícies foram pré-ativadas em uma solução diluída de ácido fluorídrico contendo PdCl2. Em seguida, foi empregado um banho químico alcalino diluído em água deionizada contendo 15 g/l NiSO4.6H2O; 0,1 a 0,3 g/l CuSO4.5H2O; 15 g/l Na2HPO2.H2O e 60 g/l Na3C6H5O7.2H2O na temperatura de 80OC sendo que NH4OH foi adicionado até que o pH do banho atingisse o valor de 8,0. Verificamos que a concentração do sal de cobre na solução de deposição afeta substancialmente a quantidade de cobre nos depósitos de CuNixPy. As concentrações planares e as composições dos filmes depositados foram obtidas através da técnica de espectrometria de retroespalhamento de Rutherford (RBS) e a morfologia superficial foi caracterizada através da técnica de microscopia de força atômica (AFM). A solução: 15 g/l NiSO4.6H2O + 0,3 g/l CuSO4.5H2O + 15 g/l Na2HPO2.H2O + 60 g/l Na3C6H5O7.2H2O + NH4OH (pH 8.0) na temperatura de 80OC foi a escolhida na obtenção da liga CuNiP0,5 para a construção de termopares Cu/CuNiP0,5 os quais apresentaram potência termoelétrica de aproximadamente (866) V/oC semelhante aos valores típicos apresentados na literatura para Cu/CuNi. / In this work, it was studied chemical depositions of CuNixPy alloys and it was fabricated Cu/CuNixPy thermocouples onto silicon wafer surfaces. Initially, surfaces were pre-activated in a diluted hydrofluoric acid solution containing PdCl2. Following, it was used a de-ionizedwater- diluted alkaline chemical bath containing 15 g/l NiSO4.6H2O; 0,1-0,3 g/l CuSO4.5H2O; 15 g/l Na2HPO2.H2O and 60 g/l Na3C6H5O7.2H2O at temperature of 80OC where NH4OH was added until ph was 8.0. The concentration of copper salt in the deposition solution greatly affected the Cu content of the CuNixPy deposits. Areal concentration and composition were measured by Rutherford Backscattering Spectrometry (RBS) and surface morphology was characterized by Atomic Force Microscopy (AFM). The solution: 15 g/l NiSO4.6H2O; 0.3 g/l CuSO4.5H2O; 15 g/l Na2HPO2.H2O; 60 g/l Na3C6H5O7.2H2O; NH4OH (pH 8.0) at the temperature of 80OC was chosen to obtain the CuNiP0.5 alloy to fabricate Cu/CuNiP0.5 thermocouples with thermoelectric power of about (866) V/oC, which is similar to the typical values reported in literature for Cu/CuNi.

Environmental challenges, such as global warming, growing demand on energy, and diminishing oil sources have accelerated research on alternative energy conversion methods. Thermoelectric power generation is a promising method to convert wasted heat energy into useful electrical energy form. A temperature gradient imposed on a thermoelectric device produces a Seebeck potential. However, this temperature gradient causes thermal stresses due to differential thermal expansions and mismatching of the bonded components of the device. Thermal stresses are critical for thermoelectric devices since they can generate failures, including dislocations, cracks, fatigue fractures, and even breakdown of the entire device. Decreases in power-generation performance and operation lifetime are major consequences of these failures. In order to minimize thermal stresses in the legs without affecting power-generation capabilities, this study concentrates on structural solutions. Thermoelectric devices with non-segmented and segmented legs were modeled. Specifically, the possible effect of various leg geometries, configurations, and dimensions were evaluated using finite-element and statistical methods. Significant changes in the magnitudes and distributions of thermal stresses occurred. Specifically, the maximum equivalent stresses in the rectangular-prism and cylindrical legs were 49.9 MPa and 43.3 MPa, respectively for the temperature gradient of 100ºC. By using cylindrical legs with modified dimensions, decreases in the maximum stresses in legs reached 21.2% without affecting power-generation performance. Moreover, the effect of leg dimensions and coaxial-leg configurations on power generation was significant; in contrast, various leg geometries and rotated-leg configurations had very limited affect. In particular, it was possible to increase power output from 20 mW to 65 mW by simply modifying leg widths and heights within the defined range. It should be noted, however, this modification also increased stress levels. It is concluded that leg geometries, configurations, and dimensions can be redesigned for improved durability and overall performance of thermoelectric devices.

Brazil\'s discoveries of large gas reservoirs in the offshore ultra-deep waters of the presalt fields show a promising scenario, along with strategic investment and adequate policy, for the development of natural gas infrastructure and a sustainable transition in the Brazilian electricity mix. Such transition should occur through the use of transnational natural gas pipelines connected to large industrial facilities and power stations, as part of strategic planning to expand industrial usage, and avoid the shortage of electricity supply, with economic and environmental advantages. Since the most important debates of the new millennium are focused on globalization and sustainable development for nations, transnational energy integration in Latin America has been receiving increasingly attention from researchers and policy makers. In this overall context, the purpose of the present research was to develop a model to study, in a comparative manner, the thermoelectric generation, as well as to analyze the effect of legal frameworks and governmental policies on the development of infrastructure and natural gas market in Brazil, with a detailed study of the most relevant market and regulatory mechanisms. A comparison was performed in terms of the most relevant regulatory legislation in Brazil and other relevant Member States of the South American economic block. The study also evaluates the sanctions imposed by ANEEL Resolution n. 583 of 2013 on suppliers, due to the lack of NG supply for thermoelectric utilities, proposing an alternative formula, thought to mitigate the influence of averages and other electricity market parameters, therefore decreasing the sanction value for the NG supplier, without compromising the contract neutrality. Different factors were analyzed in order to determine which technology would be the most efficient in terms of levelized costs. Results indicated that natural gas-fired generators are very competitive and efficient, when compared to other thermoelectric sources in both economic and environmental aspects, even when externalities were included. Also, that further strategic investment and adequate regulatory policy changes are required from the market agents, in order to foster the development of pipeline infrastructure and the expansion of natural gas use in Brazil. The study also demonstrates that the environmental impact of the CH4 leakage equals that of CO2 release from combustion at about 4.2% leakage on a mass basis, when methane leakage rises to a level in which natural gas becomes as greenhouse gas intensive as biomass. / As descobertas de substanciais reservatórios de gás natural no Brasil, localizados em águas ultra profundas após a camada Pré-Sal, demonstram um cenário promissor, aliado a investimentos estratégicos e a políticas públicas adequadas, para o desenvolvimento da infraestrutura de gás natural e uma transição sustentável na matriz elétrica brasileira. Tal transição deveria ocorrer por intermédio do uso de tubulação transnacional de gás natural, conectada a grandes instalações industriais e a usinas termelétricas, como parte de um planejamento estratégico voltado à expansão do uso de gás natural na indústria e a evitar a escassez no suprimento de energia elétrica, com vantagens econômicas e ambientais. Considerando que os debates mais relevantes do novo milênio estão focados na globalização e no desenvolvimento sustentável das nações, a integração transnacional na América Latina tem recebido crescente atenção por parte de pesquisadores e de elaboradores das políticas públicas. Nesse contexto geral, a proposta da presente pesquisa foi a de desenvolver um modelo para estudar, de uma forma comparativa, a geração termelétrica, bem como analisar o impacto do arcabouço jurídico-regulatório e das políticas governamentais no desenvolvimento da infraestrutura e do mercado do gás natural no Brasil, com um estudo detalhado dos mais relevantes mecanismos regulatórios e de mercado. Foi realizado, ainda, um comparativo da legislação regulatória do gás natural no Brasil com outros Estados-Membros relevantes do Mercosul. O estudo também avalia as sanções impostas pela Resolução ANEEL n. 583 de 2013 nos fornecedores, devido a corte no suprimento de gás natural para empreendimentos de geração termelétrica, propondo um cálculo alternativo visando a mitigar a influência das médias e outros parâmetros intrínsecos ao mercado de energia, dessa maneira reduzindo as sanções contratuais para o fornecedor de gás natural, sem prejudicar a neutralidade contratual. Diferentes fatores foram analisados de forma a determinar qual tecnologia seria a mais eficiente em termos de custos nivelados de eletricidade. Os resultados indicaram que as termelétricas a gás natural são muito competitivas e eficientes, quando comparadas com outros tipos de combustível, tanto pelo aspecto ambiental quanto pelo econômico, mesmo quando externalidades são incluídas. Ainda, que são necessárias mudanças nas políticas regulatórias e no investimento estratégico por parte dos agentes do mercado, de forma a incentivar o desenvolvimento de infraestrutura e a expansão do uso do gás natural no Brasil. O estudo também evidencia que o impacto ambiental do vazamento de CH4 se iguala àquele do CO2 liberado pela combustão em cerca de 4.2% em base mássica, quando o vazamento de metano atinge um nível em que seu impacto como gás do efeito estufa fica equivalente à biomassa.

Brazil\'s discoveries of large gas reservoirs in the offshore ultra-deep waters of the presalt fields show a promising scenario, along with strategic investment and adequate policy, for the development of natural gas infrastructure and a sustainable transition in the Brazilian electricity mix. Such transition should occur through the use of transnational natural gas pipelines connected to large industrial facilities and power stations, as part of strategic planning to expand industrial usage, and avoid the shortage of electricity supply, with economic and environmental advantages. Since the most important debates of the new millennium are focused on globalization and sustainable development for nations, transnational energy integration in Latin America has been receiving increasingly attention from researchers and policy makers. In this overall context, the purpose of the present research was to develop a model to study, in a comparative manner, the thermoelectric generation, as well as to analyze the effect of legal frameworks and governmental policies on the development of infrastructure and natural gas market in Brazil, with a detailed study of the most relevant market and regulatory mechanisms. A comparison was performed in terms of the most relevant regulatory legislation in Brazil and other relevant Member States of the South American economic block. The study also evaluates the sanctions imposed by ANEEL Resolution n. 583 of 2013 on suppliers, due to the lack of NG supply for thermoelectric utilities, proposing an alternative formula, thought to mitigate the influence of averages and other electricity market parameters, therefore decreasing the sanction value for the NG supplier, without compromising the contract neutrality. Different factors were analyzed in order to determine which technology would be the most efficient in terms of levelized costs. Results indicated that natural gas-fired generators are very competitive and efficient, when compared to other thermoelectric sources in both economic and environmental aspects, even when externalities were included. Also, that further strategic investment and adequate regulatory policy changes are required from the market agents, in order to foster the development of pipeline infrastructure and the expansion of natural gas use in Brazil. The study also demonstrates that the environmental impact of the CH4 leakage equals that of CO2 release from combustion at about 4.2% leakage on a mass basis, when methane leakage rises to a level in which natural gas becomes as greenhouse gas intensive as biomass. / As descobertas de substanciais reservatórios de gás natural no Brasil, localizados em águas ultra profundas após a camada Pré-Sal, demonstram um cenário promissor, aliado a investimentos estratégicos e a políticas públicas adequadas, para o desenvolvimento da infraestrutura de gás natural e uma transição sustentável na matriz elétrica brasileira. Tal transição deveria ocorrer por intermédio do uso de tubulação transnacional de gás natural, conectada a grandes instalações industriais e a usinas termelétricas, como parte de um planejamento estratégico voltado à expansão do uso de gás natural na indústria e a evitar a escassez no suprimento de energia elétrica, com vantagens econômicas e ambientais. Considerando que os debates mais relevantes do novo milênio estão focados na globalização e no desenvolvimento sustentável das nações, a integração transnacional na América Latina tem recebido crescente atenção por parte de pesquisadores e de elaboradores das políticas públicas. Nesse contexto geral, a proposta da presente pesquisa foi a de desenvolver um modelo para estudar, de uma forma comparativa, a geração termelétrica, bem como analisar o impacto do arcabouço jurídico-regulatório e das políticas governamentais no desenvolvimento da infraestrutura e do mercado do gás natural no Brasil, com um estudo detalhado dos mais relevantes mecanismos regulatórios e de mercado. Foi realizado, ainda, um comparativo da legislação regulatória do gás natural no Brasil com outros Estados-Membros relevantes do Mercosul. O estudo também avalia as sanções impostas pela Resolução ANEEL n. 583 de 2013 nos fornecedores, devido a corte no suprimento de gás natural para empreendimentos de geração termelétrica, propondo um cálculo alternativo visando a mitigar a influência das médias e outros parâmetros intrínsecos ao mercado de energia, dessa maneira reduzindo as sanções contratuais para o fornecedor de gás natural, sem prejudicar a neutralidade contratual. Diferentes fatores foram analisados de forma a determinar qual tecnologia seria a mais eficiente em termos de custos nivelados de eletricidade. Os resultados indicaram que as termelétricas a gás natural são muito competitivas e eficientes, quando comparadas com outros tipos de combustível, tanto pelo aspecto ambiental quanto pelo econômico, mesmo quando externalidades são incluídas. Ainda, que são necessárias mudanças nas políticas regulatórias e no investimento estratégico por parte dos agentes do mercado, de forma a incentivar o desenvolvimento de infraestrutura e a expansão do uso do gás natural no Brasil. O estudo também evidencia que o impacto ambiental do vazamento de CH4 se iguala àquele do CO2 liberado pela combustão em cerca de 4.2% em base mássica, quando o vazamento de metano atinge um nível em que seu impacto como gás do efeito estufa fica equivalente à biomassa.

Superfícies de silício (100) foram inicialmente pré-ativadas em uma solução diluída de ácido fluorídrico contendo PdCl2. Após essa etapa, filmes finos de Cu-Ni-P foram quimicamente depositados utilizando-se um banho químico contendo 15g/l NiSO4.6H2O; 0.2 g/l CuSO4.5H2O; 15 g/l Na2HPO2.H2O e 60 g/l Na3C6H5O7.2H2O na temperatura de 80ºC onde foi adicionado NH4OH até que o pH da solução atingisse 8,0. Foi observado que as porcentagens estequiométricas de Ni e Cu variaram substancialmente no intervalo de 1 a 3min, e se tornaram praticamente estáveis em 50% e 35%, respectivamente, quando o tempo de deposição foi superior a 3min. Além disso, a porcentagem de P permaneceu quase constante em torno de 17-18% para todos os tempos de deposição. A distribuição de alturas nas imagens FE-SEM resultou bimodal para tempos na faixa de 1 e 3min onde a predominância do modo de maior altura aumentou substancialmente para o tempo de 3min. Tal fato serviu para corroborar a evolução da morfologia superficial de grãos menores com diâmetros na faixa de 0,02 a 0,1µm, predominantemente compostos de Ni, para grãos maiores, na faixa de 0,1 a 0,3µm e predominantemente compostos de Cu. Após um recozimento a 100oC durante 10min em ambiente 20%O2+80%N2, observou-se uma mudança na morfologia superficial em que os aglomerados de fósforo (Po) desapareceram enquanto que os grãos que compunham a imagem não mudaram substancialmente de tamanho após o recozimento. Apesar do desaparecimento dos aglomerados, a concentração de fósforo ainda apresentou valor semelhante ao valor de antes do recozimento (~17-18%). As análises de difração de raios X (XRD) indicaram o aparecimento de um pico de difração alargado ao redor de 22,6º característico de óxido de fósforo (P2O5) com estrutura vítrea amorfa significando que o fósforo em estado puro foi transformado na sua forma oxidada. Por outro lado, picos substancialmente menos intensos de NiO, Ni3P e Si5P6O25 foram observados. Verificou-se também para os filmes recozidos em N2+O2 que a resistividade aumentou para todos os tempos de deposição e o poder termoelétrico medido resultou quase independente do tempo de deposição e, portanto, foi quase independente da espessura do filme para as diferentes temperaturas medidas na faixa de 40 a 120ºC. / Silicon surfaces (100) were initially pre-activated in a diluted hydrofluoric acid solution containing PdCl2. After this step, Cu-Ni-P thin films were chemically deposited using a chemical bath containing 15g/l NiSO4.6H2O; 0.2 g/l CuSO4.5H2O; 15 g/l Na2HPO2.H2O e 60 g/l Na3C6H5O7.2H2O at the temperature of 80°C where NH4OH was added until the pH of the solution reached 8.0. It was observed that the stoichiometric percentages of Ni and Cu varied substantially for deposition time in the range of 1 to 3min, and became practically invariant at 50% and 35%, respectively, when the deposition time was greater than 3min. In addition, the percentage of P remained almost constant at around 17-18% for all the deposition times. The distribution of heights in the FE-SEM images resulted bimodal for times in the range of 1 and 3min where the predominance of the higher average height mode increased substantially for the time of 3min. This fact allowed one to corroborate the superficial morphology passing from smaller grains with diameters in the range of 0.02 to 0.1µm, predominantly composed of Ni to larger grains in the range of 0.1 to 0.3µm with Cu predominant composition. After an annealing at 100°C for 10min in a 20%O2+80%N2 environment, the phosphorus (Po) agglomerates disappeared while the size of the grains did not change substantially after the annealing. Despite the disappearance of the agglomerates, the phosphorus concentration still remained unchanged (~ 17-18%). X-ray diffraction (XRD) analysis showed a broad diffraction peak around 22.6º, which is characteristic of an amorphous vitreous structure (P2O5). In addition, substantially less intense peaks showing small amounts of NiO, Ni3P and Si5P6O25 were observed. It was also verified for the N2+O2 annealed films that the resistivity increased for practically all the deposition times and the measured thermoelectric power was almost independent of the deposition time and, therefore, was also independent of the film thickness for the various temperatures in the range from 40 to 120ºC.

Titanium dioxide, TiO2, has potential applications as a photoelectrode for photoelectrochemical generation of hydrogen by splitting water using solar energy and as a photocatalyst for water purification. This study is part of the UNSW research program to process TiO2-based oxide semiconductors as high-performance photoelectrodes and photocatalysts. This study investigates the effect of defect disorder on semiconducting properties of polycrystalline TiO2. This study involved the processing of high-purity polycrystalline TiO2 and determination of its semiconducting properties through measurement of electrical conductivity and thermoelectric power at elevated temperatures (1073-1323K) in controlled oxygen activities [1x10-13 Pa < p(O2) < 75 kPa]. The study included two types of experiments: Determination of electrical properties under conditions of gas/solid equilibrium. The data obtained was used to derive defect disorder and related semiconducting properties Monitoring of electrical properties during equilibration. This data was used to determine the chemical diffusion coefficient. The data obtained under equilibrium conditions indicates that oxygen may be used as a dopant to impose controlled semiconducting properties. In reduced conditions TiO2 is an n-type semiconductor and under oxidizing conditions TiO2 is a p-type semiconductor. The n-type behaviour is associated with oxygen vacancies as the predominant defects and titanium interstitials as the minority defects. The p-type behaviour is closely related to titanium vacancies that are formed during prolonged oxidation. Charge transport at elevated temperature was shown to involve substantial contribution from ions. Analysis of electrical properties enabled determination of several defect-related quantities including the activation enthalpy for oxygen vacancy formation, and the activation energy of the electrical conductivity components related to electrons, holes and ions. The kinetic data obtained during gas/solid equilibration enabled determination of the chemical diffusion coefficient which exhibited a complex dependence on nonstoichiometry. In addition, prolonged oxidation showed that equilibration occurred in two kinetic regimes. One for highly mobile oxygen vacancies and titanium interstitials which quickly reached an ??operational equilibrium?? within hours and another slow kinetic regime for equilibration of titanium vacancies over many thousand hours. The determined chemical diffusion coefficient data may be used to select the processing conditions required to impose uniform concentration of defects within a TiO2.