The thesis deals with the problems of alternative energy sources with focus on solar energy sources in present practice. The thesis introduction explains the reasons of the changes in the global fuel-energy balance and their adverse effects, characterizes individual alternative energy sources and their practical applicability. The main focus is on exploitation of solar energy. After explaining the principle of thermonuclear reactions as the source of energy in the Sun, the thesis analyses the question of production of photovoltaic cells and a solar module. It describes the types of commonly used accumulators, charges and voltage transformers. It points out all factors, which must be taken into account when handling solar panels in practice. In the last chapter, it in particular deals with the didactic instructions for teaching the topic of alternative energy sources at elementary schools, as well as the need for introduction of the mentioned topic to teacher colleges.

xii, 97 p. / Electricity generated from woody biomass material is generally considered renewable energy and has been considered carbon neutral. However, recent criticism from scientists argues that the greenhouse gas (GHG) emission profile of bioenergy is nuanced and the carbon neutral label is inappropriate. An initial carbon debt is created when a forest is harvested and combusted for bioenergy. Because forests re-grow over a period of years, life cycle analyses show that bioenergy generated from whole trees from forests may not reduce GHG emissions in the short term, as required to combat climate change. State renewable portfolio standards and federal laws and proposed legislation designed to incentivize renewable energy typically define eligible forms of biomass that qualify for these incentives. Most of these definitions are very broad and do not account for GHG emissions from bioenergy. Federal and state laws should incorporate life cycle analyses into definitions of eligible biomass so that these laws incentivize biomass electricity that reduces GHG emissions in the next several decades. / Committee in charge: Roberta Mann, Chairperson; Scott Bridgham, Member

xx, 134 p. : ill. (some col.) / Solar energy is a green alternative to fossil fuels but solar technologies to date have been plagued by low conversion efficiencies and high input costs making solar power inaccessible to much of the developing world. Semiconductor nanoparticles (NPs) may provide a route to efficient, economical solar devices through a phenomenon called multiple exciton generation (MEG). Through MEG, semiconductor NPs use a high-energy input photon to create more than one exciton (electron-hole pair) per photon absorbed, thereby exhibiting large photoconversion efficiencies. While MEG has been studied in many NP systems, and we understand some of the factors that affect MEG, a rigorous analysis of the NP-ligand interface with respect to MEG is missing. This dissertation describes how the NP ligand shell directly affects MEG and subsequent charge carrier recombination. Chapter I describes the motivation for studying MEG with respect to NP surface chemistry. Chapter II provides an in-depth overview of the transient absorption experiment used to measure MEG in the NP samples. Chapter III highlights the effect of oleic acid and sodium 2, 3-dimercaptopropane sulfonate on MEG in PbS NPs. The differences in carrier recombination were accounted for by two differences between these ligands: the coordinating atom and/or the secondary structure of the ligand. Because of these hypotheses, experiments were designed to elucidate the origin of these effects by controlling the NP ligand shell. Chapter IV details a viable synthetic route to thiol and amine-capped PbS NPs using sodium 3-mercaptopropane sulfonate as an intermediate ligand. With the versatile ligand exchange described in Chapter IV, the MEG yield and carrier recombination was investigated for ligands with varying headgroups but the same secondary structure. The correlation of ligand donor atom to MEG is outlined in Chapter V. Finally, Chapter VI discusses the conclusions and future outlook of the research reported in this dissertation. This dissertation includes previously published and unpublished co-authored material. / Committee in charge: Dr. Geraldine L. Richmond, Chairperson; Dr. David R. Tyler, Advisor; Dr. Mark C. Lonergan, Member; Dr. Catherine J. Page, Member; Dr. Hailin Wang, Outside Member

abstract: This is a two part thesis: Part – I This part of the thesis involves automation of statistical risk analysis of photovoltaic (PV) power plants. Statistical risk analysis on the field observed defects/failures in the PV power plants is usually carried out using a combination of several manual methods which are often laborious, time consuming and prone to human errors. In order to mitigate these issues, an automated statistical risk analysis (FMECA) is necessary. The automation developed and presented in this project generates about 20 different reliability risk plots in about 3-4 minutes without the need of several manual labor hours traditionally spent for these analyses. The primary focus of this project is to automatically generate Risk Priority Number (RPN) for each defect/failure based on two Excel spreadsheets: Defect spreadsheet; Degradation rate spreadsheet. Automation involves two major programs – one to calculate Global RPN (Sum of Performance RPN and Safety RPN) and the other to find the correlation of defects with I-V parameters’ degradations. Based on the generated RPN and other reliability plots, warranty claims for material defect and degradation rate may be made by the system owners. Part – II This part of the thesis involves the evaluation of Module Level Power Electronics (MLPE) which are commercially available and used by the industry. Reliability evaluations of any product typically involve pre-characterizations, many different accelerated stress tests and post-characterizations. Due to time constraints, this part of the project was limited to only pre-characterizations of about 100 MLPE units commercially available from 5 different manufacturers. Pre-characterizations involve testing MLPE units for rated efficiency, CEC efficiency, power factor and Harmonics (Vthd (%) and Ithd (%)). The pre-characterization test results can be used to validate manufacturer claims and to evaluate the product for compliance certification test standards. Pre-characterization results were compared for all MLPE units individually for all tested parameters listed above. The accelerated stress tests are ongoing and are not presented in this thesis. Based on the pre-characterizations presented in this report and post-characterizations performed after the stress tests, the pass/fail and time-to-failure analyses can be carried out by future researchers. / Dissertation/Thesis / Masters Thesis Engineering 2015

abstract: The operating temperature of photovoltaic (PV) modules is affected by external factors such as irradiance, wind speed and ambient temperature as well as internal factors like material properties and design properties. These factors can make a difference in the operating temperatures between cells within a module and between modules within a plant. This is a three-part thesis. Part 1 investigates the behavior of temperature distribution of PV cells within a module through outdoor temperature monitoring under various operating conditions (Pmax, Voc and Isc) and examines deviation in the temperature coefficient values pertaining to this temperature variation. ANOVA, a statistical tool, was used to study the influence of various factors on temperature variation. This study also investigated the thermal non-uniformity affecting I-V parameters and performance of four different PV technologies (crystalline silicon, CdTe, CIGS, a-Si). Two new approaches (black-colored frame and aluminum tape on back-sheet) were implemented in addition to the two previously-used approaches (thermally insulating the frame, and frame and back sheet) to study temperature uniformity improvements within c-Si PV modules on a fixed latitude-tilt array. This thesis concludes that frame thermal insulation and black frame help reducing thermal gradients and next best viable option to improve temperature uniformity measurements is by using average of four thermocouples as per IEC 61853-2 standard. Part 2 analyzes the temperature data for two power plants (fixed-tilt and one-axis) to study the temperature variation across the cells in a module and across the modules in a power plant. The module placed in the center of one-axis power plant had higher temperature, whereas in fixed-tilt power plant, the module in north-west direction had higher temperatures. Higher average operating temperatures were observed in one-axis tracking as compared to the fixed-tilt PV power plant, thereby expected to lowering their lifetime. Part 3 focuses on determination of a thermal model coefficients, using parameters similar to Uc and Uv thermal loss factors used in PVsyst, for modules of four different PV technologies experiencing hot-desert climate conditions by statistically correlating a year-long monitored data. Thermal models help to effectively quantity factors influencing module temperatures to estimate performance and energy models. / Dissertation/Thesis / Masters Thesis Mechanical Engineering 2016

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work aims at the development of an instrumentation prototype to monitor, control and drive a proton exchange membrane fuel cell (PEMFC) and its ancillary equipment. The first stage of this work is related to PEMFC stack modeling and the second is focused on electronic instrumentation to obtain practical data regarding to the stack behavior. Several theoretical models are analyzed. However, more attention is paid to the electronic model. Considering other electronic PEMFC models, changes were made to make it a more accurate. In this way, this modified model was validated by laboratory static and dynamic tests. These tests were compared with real data, available from the manufacturer s manual and other information from literature. To evaluate the variation in the main external parameters (reactant pressures, temperature, humidity of the membranes and coolant fluids, stoichiometric ratio, power, current and voltage) a full fuel cell instrumentation circuitry was developed to monitor and control them. This software is fully implemented in Labview, so as to verify and to control the whole fuel cell efficiency by using only a computer-based terminal. Additionally, the whole instrumentation system is presented and discussed. Finally, experimental tests were carried out to evaluate a by-pass technique (set of controlled shortcircuits) to maximize the stack output power. / Esta dissertação refere-se ao desenvolvimento de um sistema de monitoramento, acionamento e controle de uma pilha de células a combustível (CaC) do tipo PEM e de seu equipamento auxiliar. A primeira etapa deste trabalho é relacionada à modelagem da CaC e a segunda refere-se à instrumentação eletrônica para obtenção de dados práticos da pilha. Para os estudos teóricos vários modelos matemáticos são estudados, com maior ênfase à modelagem eletrônica de CaC. Para o modelo eletrônico são propostas modificações em relação a sua proposta original e sua validação é realizada através de testes estáticos e dinâmicos, e pela comparação dos dados obtidos com dados de fabricantes e também de outros autores. De modo a avaliar o impacto que a variação das principais grandezas de controle causam na eficiência da CaC é apresentado um sistema de monitoramento e controle baseado no programa Labview. Este sistema foi implementado em um protótipo de laboratório que faz uso de uma placa de aquisição para coleta de dados e geração de sinais PWM de controle. Também é apresentada a instrumentação eletrônica necessária para o mesmo protótipo. A pressão de entrada dos reagentes, a temperatura de operação, a umidade da membrana, o fluxo de ar e a razão estequiométrica são as principais variáveis a serem monitoradas e controladas. Também são realizados ensaios de funcionamento dinâmico da pilha com a aplicação da técnica de by-pass ou curtos-circuitos entre o anodo e o catodo.

Resumo: O estudo aborda as novas tendências da gestão ambiental em reduzir a poluição, evitando-se as queimadas de cana-de-açúcar e o aproveitando de resíduos agrícolas para fins de geração de energia alternativa, de ciclo limpo, com o emprego de biomassa, atendendo as recomendações da Agenda 21 e do protocolo de Kyoto de reduzir fontes poluidoras e melhorar a qualidade de vida e da saúde da população com o emprego de Mecanismo de Desenvolvimento Limpo - MDL. Mostra que a modelagem matemática de simulação de processos operacionais é um instrumento eficaz de gerenciamento auxiliando na tomada de decisões, possibilitando ao setor sucroalcooleiro introduzir este instrumento de gestão, pouco empregado pelo mesmo, reduzindo, com isto, riscos e custos na definição de rotas tecnológicas de processos pelas empresas. Apresenta uma equação de simulação de diversas rotas tecnológicas para adequar o tamanho do particulado do palhiço, ao sistema existente que alimenta as caldeiras e que permite avaliar as vantagens econômicas de se empregar o palhiço, e/ou a matéria estranha vegetal da colheita da cana-de-açúcar, como fonte de biomassa para fins de cogeração, juntamente com o bagaço e para isto, define a rota de menor custo. Nas simulações realizadas foi possível determinar que a rota tecnológica de menor custo de adequação dessa biomassa foi a da colheita integral seguida do recolhimento em fardos e a granel que não apresentaram diferenças significativas entre si, ressaltando que análise da simulação deve abranger ambos os setores agrícola e industrial resultando em uma visão mais adequada. Determinou-se, por equações lineares que o palhiço pode contribuir com o incremento da disponibilidade energética adicional ao bagaço na ordem de 5,59% a 55,94% dependendo das características do canavial e do percentual de recolhimento adotado... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This study reflects on the new tendencies of environmental management in reducing pollution avoiding burning the sugar-cane and taking the advantage of agricultural residues, in order to generate clean cycle of alternative energy with the utilization of biomass, meeting the recommendations of "Agenda 21" and Kyoto Protocol, to reduce pollutant sources and improve the population's health and life quality, making a good use of - Clean Development Mechanism (MDL).The study shows that the mathematical modeling of operational process simulation is an effective instrument of management that supports a taking of stand, to enable the sugar-cane sector to introduce this not much utilized instrument, reducing the risks and costs in the definition of technological routes of processes by the companies. It presents an equation of simulation of several technological route to adapt the size of the fragment of the "palhiço", to the existent system that it feeds the kettles and that it allows to evaluate the economical advantages of using the "palhiço", agricultural residue of the crop of the sugar-cane, as biomass source for co-generation aim, together with the bagasse and for this purpose, it defines the route of smaller cost. In the accomplished simulations it was possible to determine that the technological route of smaller cost of adaptation of the "palhiço" (crop residues) was the one of the crop in bales following by the crop in bulk and finally for the system of crop of integral sugar cane. Emphasizing that analysis of the simulation should include both agricultural and industrial sections for not incurring in mistakes of isolated evaluation. It was also determined by linear equations that the "palhiço" can contribute with the increment of the additional energy readiness to the bagasse in the strip from 5,59% to 55,94% depending on the to suck cane plantation...(Complete abstract, click eletronic address below) / Orientador: Elias José Simon / Coorientador: Tomaz Caetano Cannavam Ripoli / Banca: Nilson Augusto Villa Nova / Banca: Valter Francisco Molina Junior / Banca: José Carlos Teixeira da Silva / Banca: Edgar Gomens F. de Beauclair / Doutor

Made available in DSpace on 2014-12-17T14:56:16Z (GMT). No. of bitstreams: 1 RodrigoLB_DISSERT.pdf: 2422493 bytes, checksum: d216abfd7470b7951cb5443aaa1b133a (MD5) Previous issue date: 2014-01-22 / The scarcity of natural resources and the search for alternative energy sources promote a rapid change in the energy world. Among the renewable energy sources, solar energy is the most promising, presenting technology of greatest growth rate nowadays. Researchers around the world are seeking ways to facilitate their progress, developing technologies with higher efficiency and lower cost. As a contribution to global progress, this master thesis proposes the development of a strategy of maximum power tracking based on perturbation and observation method for photovoltaic systems. The proposed control strategy is based on active power balance of the system, with a reduced number of sensors. It also allows the PV system to act as a regulator of the power quality at the point of commom coupling (PCC), compensating the harmonic distortion and power factor of the current netw / A escassez dos recursos naturais e a busca por fontes de energia alternativa promovem uma r?pidamudan?a namatriz energ?tica mundial. Dentre as fontes de energia renov?veis a energia solar ? a mais promissora, visto que ela apresenta a maior taxa de crescimento na atualidade. Pesquisadores de todo o mundo t?m buscado formas de viabiliza??o do seu progresso, desenvolvendo tecnologias com maior efici?ncia e menor custo. Como forma de contribuir para o avan?o mundial, neste trabalho ? proposto o desenvolvimento de uma estrat?gia de rastreamento da m?xima pot?ncia, baseado no m?todo perturba??o e observa??o, para sistemas fotovoltaicos. A estrat?gia de controle proposta ? baseada no balan?o de pot?ncia ativa do sistema e utiliza um n?mero reduzido de sensores. Ela tamb?m permite que o sistema fotovoltaico atue como regulador da qualidade de energia no ponto de conex?o, compensando assim a distor??o harm?nica das correntes da rede e corrigindo o fator de pot?ncia. Resultados de simula??o e experimentais s?o apresentados para validar a estrat?gia proposta

Made available in DSpace on 2015-05-14T13:16:15Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 3625280 bytes, checksum: 20e0d4cccc3dc2745813e44f259dd36b (MD5) Previous issue date: 2013-04-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This research aims at knowing to what extend the environmental attitudes may be predicted in terms of the human values and in relation to the person-environment relationships. More especially it is intended to know how the human values and person- nature relationships explain the pro environmental attitudes that promote the sustainable use of natural resources having as focus the production and consume of energy. In this sense, the theoretical approach highlights themes concerning conventional and alternative energy use, besides of the values constructs, attitudes of preservation and environmental inclusion. Two studies were carried out. The study 1 aimed at knowing how the environmental attitudes were correlated with human values, the attitudes towards the conventional and solar attitudes and the connectivity with environmental inclusion. This study counted on a non probability convenience sample of 307 participants came from the general population (63%) and students from Environmental Technology Course offered by IFMT- Campus Cuiabá - Bela Vista and Forestry Engineering Course given by UFMT, Cuiabá (MT). The subjects ages varied between 18 and 85 years (m =30, 8, sd = 14.43), the majority was female (62%). The participants answered the following research instruments: Environmental attitudes inventory, Environmental Connectivity Scale, Solar Energy Attitudes Scale, Conventional Energy Attitudes Scale, Basic Values Questionnaire, Social Desirability Scale and sociodemographic questions. The results indicated that participants are concerned about the environment; they had positive attitudes towards to sustainable energy sources, besides of revealing the feeling of being included to the natural environment. Concerning the super-personal values, these were positively correlated with preservation attitudes, while the social values did it with those of utilization. The attitudes towards solar energy were positively correlated with the preservation attitudes, but those concerning the conventional energy did it negatively, and finally, consistent with the previous result, the attitudes towards solar energy were positively correlated with environmental connectivity and inclusion. It was observed an opposite pattern towards conventional energy attitudes. The Study 2 aimed at replicating the findings described above. In this sense, this study counted on a non probability convenience sample of 175 participants from the general population of the cities of Cuiabá and Barão de Melgaço. Their ages were between 18 and 92 years (mean = 37.7, sd =14,43), the majority was female (62%). These participants answered the same questionnaires above described. In general, it was observed the same results of Study 1. It was evidenced that the participants of Barão de Melgaço, despite of having the prevalence of daily activities associated to the natural environment, they presented lower propensities to environmental protection and care behaviors when compared to participants from the capital city. In conclusion, the attitudes of environmental preservation, as well as, the environmental connectivity and inclusion may be important to explain attitudes towards solar and conventional energy, in this sense, the human values, especially the super-personal; values had the leading role in this context. It is trust, then, that this thesis represents an important contribution to the literatures of Social Psychology and Environmental Psychology, offering opportunities for considering future researches, mainly, contributing to the public policies in order to ensure environmental education and promote environmentally sustainable behaviors. / Esta pesquisa tem por objetivo geral conhecer em que medida as atitudes ambientais podem ser preditas em função dos valores humanos e da relação pessoa-ambiente. Especificamente, pretende-se conhecer como os valores humanos e a relação dos indivíduos com a natureza explicam atitudes pró-ambientais que promovam a utilização sustentável dos recursos naturais, tendo como focos a produção e o consumo de energia. Neste sentido, organizou-se o marco teórico tratando os temas de uso e conservação de energias convencionais e alternativas, além dos construtos valores, atitudes de preservação e inclusão ambiental. Dois estudos foram realizados. O Estudo 1 objetivou conhecer como as atitudes ambientais se correlacionavam com os valores humanos, as atitudes frente às energias convencional e solar, e a conexão e inclusão ambiental. Contou-se com uma amostra de conveniência (não probabilística) de 307 participantes provenientes da população geral (63%) e estudantes universitários de cursos de Tecnologia em Gestão Ambiental e Engenharia Florestal de Cuiabá (MT). Estes tinham idades variando entre 18 e 85 anos (m = 30,8; dp = 14,43), sendo a maioria do sexo feminino (62%), tendo respondido os seguintes instrumentos: Inventário de Atitudes Ambientais, Escala de Conexão Ambiental, Escala de Inclusão Ambiental, Escala de Atitudes frente à Energia Solar, Escala de Atitudes frente à Energia Convencional, Questionário dos Valores Básicos, Escala de Desejabilidade Social e perguntas demográficas. Os resultados indicaram que os participantes se preocupam com o meio ambiente, tendo atitudes positivas frente às fontes de energias sustentáveis, além de se sentirem incluídas ao meio ambiente natural. No caso, os valores suprapessoais se correlacionaram positivamente com as atitudes de preservação, enquanto os sociais o fizeram com aquelas de utilização; as atitudes frente à energia solar se correlacionaram positivamente com as de preservação, porém aquelas frente à energia convencional o fizeram negativamente; e, finalmente, coerente com o resultado anterior, as atitudes frente à energia solar se correlacionaram positivamente com a conexão e inclusão ambiental, tendo sido observado um padrão oposto para as atitudes frente à energia convencional. O Estudo 2 objetivou replicar os achados anteriormente descritos. Neste sentido, contou-se com amostra de conveniência (não probabilística) de 175 participantes da população geral dos municípios de Cuiabá e Barão de Melgaço, os quais tinham com idades entre 18 e 92 anos (m = 37,7; dp = 14,43), sendo a maioria do sexo feminino (62%). Tais participantes responderam os mesmos questionários anteriormente descritos. Em termos gerais, observaram-se os mesmos resultados do Estudo 1. Destaca-se, entretanto, que os participantes de Barão de Melgaço, apesar do predomínio de atividades diárias relacionadas com o meio ambiente natural, apresentam propensões menores para comportamentos de proteção e cuidado ambiental em comparação com aqueles de Cuiabá. Concluiu-se que as atitudes ambientais de preservação, assim como a conexão e inclusão ambiental, podem ser importantes para explicar as atitudes frente à energia solar e convencional, cabendo aos valores humanos, sobretudo os suprapessoais, papel de destaque neste contexto. Confia-se, portanto, que a presente tese represente contribuição importante para a literatura da psicologia social e ambiental, oferecendo oportunidade para pensar pesquisas futuras e, principalmente, contribuir com políticas públicas com o fim de assegurar a educação ambiental e promover condutas ambientalmente sustentáveis.

The aim of thesis is to assess and evaluate how energy crops affect erosion phenomena, then identify a suitable alternative crop that has anti-erosion ability. Location is evaluated in detail Trebon, as cultivation areas suitable for Phytoenergetics and biogas. Furthermore, I studied agricultural biogas plant that uses biomass as input for biogas production. To evaluate and calculate erosion parameters for a given locality the method of universal soil loss equation by Wishmeier and Smith, and the value showed crops causing erosion. The calculated values are related to locations all over the South Region. Thanks to the universal equation it is possible to find alternative crops, which cause erosion and both are suitable for biogas production.