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A hydrokinetic resource assessment of the Florida CurrentUnknown Date (has links)
The Straits of Florida has been noted as a potential location for extraction of the kydrokinetic energy of the Florida Current, in view of the strength of the current and its proximity to the shore. ... This research explores the Florida Current as a potential renewable energy source. By utilizing historical data, in situ observations of the Florida Current, and computer model data, the hydrokinetic resource of the Florida Current is characterized both spatially and temporally. Subsequently, based on the geographic variability of the hydrokinetic power and other factors that impact the economy of a hydrokinetic turbine array installation, the ideal locations for turbine array installation within the Florida Current are identified.... Additionally, an interactive tool has been developed in which array parameters are input - including installation location, turbine diameter, turbine cut-in speed, etc. - and array extraction estimates, ideal installation position, and water depth at the installation points are output. As ocean model data is prominently used in this research, a discussion about the limitations of the ocean model data and a method for overcoming these limitations are described. Globally, the distribution of hydrokinetic power intensity is evaluated to identify other currents that have a high hydrokinetic resource. / by Alana E. Smentek-Duerr. / Thesis (Ph.D.)--Florida Atlantic University, 2012. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.
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Propriété de l'État et exploitation des ressources naturelles non renouvelables en Colombie / State Ownership and Exploitation of Non-Renewable Natural Resources in ColombiaPacheco Baquero, Janneth Milena 19 December 2018 (has links)
L'objet d'intérêt dans cette recherche est dirigé à comprendre le rôle de l’Etat propriétaire dans les économies modernes et le point de partie sera l'étude de l’émergence et l'évolution de la propriété de l'Etat (la propieté etatique) et en particulier celle des ressources naturelles non renouvelables (la propriété des hydrocarbures liquides et gazeux est exclue car sont régies par des dispositions différentes et particulières sur le sujet ), les conflits qui aujourd'hui génère son exploitation, pour être confrontés à l’exercice des autres droits touchant la sensibilité des communautés et identifier différentes critères de solution. / The object of interest in this research is directed at understanding the role of the owner state in modern economies and the point of part will be the study of the emergence and evolution of state ownership (The ownership of liquid and gaseous hydrocarbons is excluded because they are governed by different and particular provisions on the subject), the conflicts which today generate its exploitation, in order to be confronted with The exercise of other rights affecting the sensitivity of communities and identify different criteria for resolution.
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Low frequency transmission for remote power generating systemsKeeli, Anupama 05 July 2011 (has links)
The goal of this Masters Thesis research is to evaluate alternative transmission systems from remote wind farms to the main grid using low-frequency AC technology. Low frequency means a frequency lower than nominal frequency (60/50Hz). The low-frequency AC network can be connected to the power grid at major substations via cyclo-converters that provide a low-cost interconnection and synchronization with the main grid. Cyclo-converter technology is utilized to minimize costs which result in systems of 20/16.66 Hz (for 60/50Hz systems respectively). Low frequency transmission has the potential to provide an attractive solution in terms of economics and technical merits.
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Cationic polymer enhanced hydrolysis of cornstarch for the production of biofuelsMaxwell, Kendra Elaine 29 March 2012 (has links)
The mechanism through which a charged polymer cationic polyacrylamide (C-PAM) operates to increase the rate of cornstarch hydrolysis was investigated. The main objective was to determine the major factors that affect the mechanism so that these parameters may be adjusted to achieve optimal hydrolysis rates. A combination of analytical methods including dynamic light scattering, optical imaging, and uv-vis spectroscopy were used to study polymer, starch, and enzyme interactions as a function of process conditions. It was found that
C-PAM binds strongly to starch granules, increasing solubilization and decreasing onset gelatinization temperature. Granule swelling was unaffected by C-PAM. Both binding of enzyme to cornstarch, and rate of cornstarch hydrolysis were found to increase in the presence of C-PAM. By analogy to previous work on cationic polymer promoted hydrolysis of cellulose, it was proposed that the polymer reduces the charge on the starch surface through a "charge-patch" mechanism. Because both enzyme and substrate are negatively charged, the positively charged polymer reduces the charge repulsion experienced by the approaching enzyme. This leads to stronger enzyme-substrate binding, and faster hydrolysis. There is a mirror image relationship between viscosity of the medium and hydrolysis rate, which allows optimization of these parameters with enzyme and C-PAM dosage. Overall, the polymer addition reduced enzyme dose by 62% depending on the conditions used, so this method could have significant economic impact on the industrial conversion of starch to ethanol.
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Bacterial indicator organisms in various classes of cisterns in the U.S. Virgin IslandsRuskin, Robert H.,1952- January 1996 (has links)
Because cisterns are exposed to the environment via their direct attachment to catchment surfaces, cistern water quality is often poor. In the U.S. Virgin Islands cisterns are involved in supplying the water needs for private homes, hotels, businesses and public housing, making them subject to the mandates of the Federal Safe Drinking Water Act. This study compares the results of the occurrence of various water quality indicators in Private Residential, Public Housing, and Hotels and Guest House cisterns in the U.S. Virgin Islands in a side-by-side analysis. Forty-seven separate independent variables were created and tested for correlation, of which only the rate at which chlorination was applied was significant. A high degree of correlation was found to exist between total and fecal coliforms. A moderate, but still significant correlation between the coliform and the heterotrophic levels in the cistern was also noted. There was no correlation between any of the bacterial indicators studied and the opportunistic pathogen Pseudomonas aeruginosa. The results show, depending upon on the type and amount of chlorination received, different bacterial indicators will predominate and that there is a logical succession from one to the next with chlorination. On the unchlorinated end of the scale, normally associated with privateresidential homes, there is a correlation between the heterotrophic bacteria and total coliform. On the other end where chlorination is constant, normally associated with public water supply systems, correlation is between total coliform and fecal coliform. The proportion at which these indicators occur is a function of the diligence at which chlorination takes place. Regression analysis showed that the heterotrophs and total coliforms were the most sensitive to chlorination while the streptococci and fecal coliform were the most resistant. Thus, what is seen is fecal coliform unmasking based upon chlorination pattern. Depending upon whether the cistern is a private or public water supply which is mandated to be treated, an appropriate indicator system based upon the likelihood of treatment can be suggested. For unchlorinated private residential home cisterns the prime indicator should be the heterotrophic plate count and for chlorinated systems the take-action organism should be the fecal coliform. P. aeruginosa should be tested for in both domestic cistern water supplies and public cistern water supply systems.
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Preparação e caracterização de revestimentos híbridos de poliuretano-ureia a partir de fontes renováveisOurique, Pedro Antonio 26 August 2016 (has links)
O presente trabalho teve como motivação investigar a viabilidade na utilização de polióis, produzidos a partir da oxidação induzida de óleo de soja comercial e utilizar estes como precursores na síntese de revestimentos híbridos de poliuretano-ureia. O óleo de soja foi escolhido por ter baixo custo, ser oriundo de fontes renováveis e apresentar em sua molécula locais com potencialidade para modificação química. Os polióis produzidos por oxidação induzida foram caracterizados por titulometria, espectroscopia na região do infravermelho com transformada de Fourier (FTIR), espectroscopia de ressonância magnética nuclear do próton 1H (RMN 1H), cromatografia por permeação em gel (GPC) para identificar a formação de grupos hidroxila em sua molécula e determinar o tempo adequado de oxidação do óleo. Após serem caracterizados, os polióis foram utilizados na síntese de revestimentos híbridos de poliuretano-ureia para serem utilizados na proteção de superfícies metálicas. Os precursores utilizados na síntese foram o óleo de soja oxidado durante 24 h (OSO-24h), óleo de soja oxidado durante 48 h (OSO-48h), 4,4'-difenil metano diisocianato (MDI), 3-aminopropil trimetoxisilano (APTMS). As análises de FTIR dos revestimentos híbridos revelaram a presença de grupos Si-O-Si, indicando a formação de uma rede híbrida, a qual também foi identificada pela análise de espectroscopia de ressonância magnética nuclear do próton 29Si (RMN 29Si), quando foi verificada a presença de estruturas T0, T1, T2 e T3 (onde o índice 0, 1, 2 ou 3 indica o número de grupos de siloxanos ligados ao átomo de silício). O mapa composicional obtido por espectroscopia de energia dispersiva (EDS) revelou que as amostras contendo aminosilano apresentam estruturas com separação de fase; isto aconteceu devido à diferença na taxa relativa de formação dos grupos ureias frente aos grupos uretanos. As análises de difração de raios X (DRX) exibem um perfil típico de materiais amorfos e a técnica de espalhamento de raios X a baixo ângulo (SAXS) revela que os domínios rígidos possuem formatos esféricos com tamanhos entre 1-6 nm. Os revestimentos aplicados em substratos metálicos foram aprovados nos testes de adesão, resistência ao impacto e flexibilidade segundo as normas da sociedade americana de testes e materiais (ASTM), entretanto, o ensaio de névoa salina revelou que os revestimentos sem o aminosilano apresentam maior resistência à corrosão, em comparado com os materiais híbridos, em virtude da formação de uma fase rica em silício, a qual atua como inicializadora da reação de corrosão. / Submitted by Ana Guimarães Pereira (agpereir@ucs.br) on 2016-10-17T15:37:27Z
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Previous issue date: 2016-10-17 / Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul, FAPERGS. / Motivation of the work was to investigate the synthesis of polyols obtained from air induced oxidation of the commercial soybean oil and use these as precursors in the preparation of polyurethane-urea hybrid coatings. Soybean oil is a feedstock that has low cost, and it comes from renewable sources. This molecule has the potential for chemical modification and use in different applications. The synthesized polyols were characterized by titration, FTIR, 1H NMR and GPC for evaluation formation of hydroxyl groups in oxidized soybean oil. After characterization polyols, were used in the synthesis of polyurethane-urea hybrid coatings for use in metal surfaces protection. The monomers used in the synthesis of hybrid coatings were oxidized soybean oil for 24 h (OSO-24), oxidized soybean oil for 48 h (OSO-48h), 4,4'-diphenyl methane diisocyanate (MDI), 3-aminopropyl trimethoxysilane (APTMS). FTIR analysis of the hybrid coatings revealed the presence of Si-O-Si bands, indicating the formation of a hybrid network, which was also identified by 29Si NMR, showing the formation of structures T0, T1, T2 and T3. SEM analysis and compositional map generated by EDS indicate that the samples with APTMS presented phase separated structures; this occurred during the difference in the relative rate of formation of urea groups when compared to urethane groups. On the other hand, the synthesized materials were amorphous and had rigid spherical shape domains with sizes between 16 nm. The films produced, when used as coatings, exhibited satisfactory mechanical behavior and excellent adhesion to metal substrates. However, its corrosion resistance is limited during of the formation of silicon rich phases.
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Preparação e caracterização de revestimentos híbridos de poliuretano-ureia a partir de fontes renováveisOurique, Pedro Antonio 26 August 2016 (has links)
O presente trabalho teve como motivação investigar a viabilidade na utilização de polióis, produzidos a partir da oxidação induzida de óleo de soja comercial e utilizar estes como precursores na síntese de revestimentos híbridos de poliuretano-ureia. O óleo de soja foi escolhido por ter baixo custo, ser oriundo de fontes renováveis e apresentar em sua molécula locais com potencialidade para modificação química. Os polióis produzidos por oxidação induzida foram caracterizados por titulometria, espectroscopia na região do infravermelho com transformada de Fourier (FTIR), espectroscopia de ressonância magnética nuclear do próton 1H (RMN 1H), cromatografia por permeação em gel (GPC) para identificar a formação de grupos hidroxila em sua molécula e determinar o tempo adequado de oxidação do óleo. Após serem caracterizados, os polióis foram utilizados na síntese de revestimentos híbridos de poliuretano-ureia para serem utilizados na proteção de superfícies metálicas. Os precursores utilizados na síntese foram o óleo de soja oxidado durante 24 h (OSO-24h), óleo de soja oxidado durante 48 h (OSO-48h), 4,4'-difenil metano diisocianato (MDI), 3-aminopropil trimetoxisilano (APTMS). As análises de FTIR dos revestimentos híbridos revelaram a presença de grupos Si-O-Si, indicando a formação de uma rede híbrida, a qual também foi identificada pela análise de espectroscopia de ressonância magnética nuclear do próton 29Si (RMN 29Si), quando foi verificada a presença de estruturas T0, T1, T2 e T3 (onde o índice 0, 1, 2 ou 3 indica o número de grupos de siloxanos ligados ao átomo de silício). O mapa composicional obtido por espectroscopia de energia dispersiva (EDS) revelou que as amostras contendo aminosilano apresentam estruturas com separação de fase; isto aconteceu devido à diferença na taxa relativa de formação dos grupos ureias frente aos grupos uretanos. As análises de difração de raios X (DRX) exibem um perfil típico de materiais amorfos e a técnica de espalhamento de raios X a baixo ângulo (SAXS) revela que os domínios rígidos possuem formatos esféricos com tamanhos entre 1-6 nm. Os revestimentos aplicados em substratos metálicos foram aprovados nos testes de adesão, resistência ao impacto e flexibilidade segundo as normas da sociedade americana de testes e materiais (ASTM), entretanto, o ensaio de névoa salina revelou que os revestimentos sem o aminosilano apresentam maior resistência à corrosão, em comparado com os materiais híbridos, em virtude da formação de uma fase rica em silício, a qual atua como inicializadora da reação de corrosão. / Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul, FAPERGS. / Motivation of the work was to investigate the synthesis of polyols obtained from air induced oxidation of the commercial soybean oil and use these as precursors in the preparation of polyurethane-urea hybrid coatings. Soybean oil is a feedstock that has low cost, and it comes from renewable sources. This molecule has the potential for chemical modification and use in different applications. The synthesized polyols were characterized by titration, FTIR, 1H NMR and GPC for evaluation formation of hydroxyl groups in oxidized soybean oil. After characterization polyols, were used in the synthesis of polyurethane-urea hybrid coatings for use in metal surfaces protection. The monomers used in the synthesis of hybrid coatings were oxidized soybean oil for 24 h (OSO-24), oxidized soybean oil for 48 h (OSO-48h), 4,4'-diphenyl methane diisocyanate (MDI), 3-aminopropyl trimethoxysilane (APTMS). FTIR analysis of the hybrid coatings revealed the presence of Si-O-Si bands, indicating the formation of a hybrid network, which was also identified by 29Si NMR, showing the formation of structures T0, T1, T2 and T3. SEM analysis and compositional map generated by EDS indicate that the samples with APTMS presented phase separated structures; this occurred during the difference in the relative rate of formation of urea groups when compared to urethane groups. On the other hand, the synthesized materials were amorphous and had rigid spherical shape domains with sizes between 16 nm. The films produced, when used as coatings, exhibited satisfactory mechanical behavior and excellent adhesion to metal substrates. However, its corrosion resistance is limited during of the formation of silicon rich phases.
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Estudo dos principais mecanismos de incentivo às fontes renováveis alternativas de energia no setor elétricoMartins, Juliana Marinho Cavalcanti 16 August 2018 (has links)
Orientador: Carla Kazue Nakao Cavaliero / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-16T02:35:03Z (GMT). No. of bitstreams: 1
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Previous issue date: 2010 / Resumo: Mecanismos regulatórios de incentivo às fontes renováveis alternativas de energia estão sendo adotados, em vários países, como forma de estímulo à produção de energia por meio destas fontes. Estes instrumentos sofreram algumas adaptações para se ajustarem às expectativas dos agentes de mercado e, com isso, novas metodologias foram sendo aplicadas. No âmbito internacional, o sistema Feed-in, o sistema de leilões e o sistema de quotas são os mecanismos mais aplicados. No Brasil, o estímulo à geração de energia por meio destas fontes foi adotado com maior expressão a partir do lançamento do Proinfa em 2002. Posteriormente, os leilões foram sendo incorporados na regulação do mercado de energia renovável, como forma de promover um aumento na capacidade de geração com fontes renováveis. O presente trabalho pretende caracterizar e classificar os instrumentos adotados em âmbito internacional e nacional, explicitando as diferenças e similaridades entre os mesmos. Por fim, é realizada uma análise preliminar da eficácia destes instrumentos, dando um enfoque especial aos critérios de alcance de metas, de aumento da capacidade instalada e de redução de custos das bandas tecnológicas / Abstract: Regulatory mechanisms to encourage renewable and alternative energy are being adopted in several countries as a way to stimulate the production of energy through these sources. These instruments have undergone some adjustments to fulfill the expectations of market players and thus, new methodologies have been applied. Internationally, the Feed-in system, the tender system and the quota system are the mechanisms usually applied. In Brazil, the stimulus to the generation of energy through these sources was used with greater expression from the launch of Proinfa in 2002. Subsequently, the auctions were being incorporated in the regulation of renewable energy market, in order to promote an increase in generation capacity from renewable sources. This work intend to characterize and classify the instruments adopted at international and national levels, highlighting the differences and similarities between them. Finally, we performed a preliminary analysis of the effectiveness of these instruments, with a special focus on the ability to reach policy goals, capacity growth and cost reduction of technology bands / Mestrado / Planejamento de Sistemas Energeticos / Mestre em Engenharia Mecânica
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Educação Ambiental Objetiva nas Faculdades/Universidades Privadas no Município de Santa Maria RS e suas localizações espaciais. / Objective Environmental Education in Private Universities in Santa Maria city, State of Rio Grande do SulLutz, Victor Luiz Scherer 09 September 2011 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work has the main goal to understand the environmental thematic that regards to environmental educa-tion at the college level, and then it was necessary to quantify the level of knowledge of environmental the-matic, often to their students as researched tract. To achieve this proposal were surveyed students knowledge level of higher education, of the Colleges / Universities privates existing in the city of Santa Maria - RS, on the environmental thematic facing the Renewable Natural Resources in its practicality and objective. To do so was made the spatial distribution of Colleges / Universities Private, the municipality of Santa Maria in order to seek a better representation and its localization. Through the use of assessment instruments were checked levels of knowledge in the students because of this we could work out the best way to enter in this community, the knowledge needed to understand sustainability environment as a whole, through the presen-tation of a program, being developed in ongoing research to fill the gap detected in environmental knowledge. The results show that knowledge of environmental issues in teaching and upper is very weak compared to similar work developed by Dra. Cleonir Martins Carpes in his PhD thesis, one can say with ab-solute certainty, that knowledge of environmental issues by students from private schools of higher education in Santa Maria, referring to the Renewable Natural Resources, is vastly inferior to knowledge of the same subject by students of public schools of primary and secondary education in the same municipality. Mathe-matical analysis and statistics confirm the report. / Este trabalho se baseia no pressuposto de que para compreender a questão ambiental, no que diz res-peito à educação ambiental, em nível superior, é necessário quantificar o nível de conhecimento, da temáti-ca ambiental, dos alunos frequentes ao respectivo estrato pesquisado.
Para atingir esta proposta foram pesquisados os conhecimentos dos alunos de nível de ensino superior, das Faculdades/Universidades privadas de Santa Maria - RS, sobre a temática ambiental voltada para os Re-cursos Naturais Renováveis, em seu caráter prático e objetivo. Para tanto foi feito a distribuição espacial das Faculdades/Universidades Privadas, do município de Santa Maria, visando procurar uma melhor represen-tação de suas localizações. Através do emprego de instrumentos de avaliações foram verificados os níveis de conhecimento em que se encontra a comunidade estudantil Santa-mariense e em face disto pôde-se elaborar a melhor forma de inserir, nesta comunidade, o conhecimento necessário para se compreender a sustentabilidade ambiental como um todo, através da apresentação, de um programa, a ser desenvolvido nos Cursos pesquisados, para suprir a lacuna detectada, em conhecimentos ambientais. Os resultados obtidos mostram que o conhecimento da temática ambiental no ensino superior é muito fraco e se comparado com trabalho similar desenvolvido pela Dra. Cleonir Martins Carpes em sua Tese de Douto-rado, pode-se afirmar, com segurança absoluta, que o conhecimento da temática ambiental pelos alunos da rede privada do Ensino Superior em Santa Maria, referente aos Recursos Naturais Renováveis, é bem infe-rior aos conhecimentos da mesma temática pelos alunos da rede pública estadual dos Ensinos Fundamen-tal e Médio do mesmo Município. As análises matemáticas e estatísticas comprovam o informe.
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PLA and cellulose based degradable polymer compositesOka, Mihir Anil 06 April 2010 (has links)
We studied PLA-microcrystalline cellulose composites, focusing on the effects of processing, particle size and surface modification. The thermal and mechanical properties of these PLA based composites were studied and the effect of cellulose addition on PLA degradation was analyzed. For our system, the degradation rate was found to depend on initial sample crystallinity, pH of the degradation media and cellulose content of the composite. Composites were prepared using solution processing and melt mixing methods. The processing methods influenced the polymer's ability to crystallize affecting the mechanical properties. Isothermal crystallization studies carried out to study the kinetics of crystallization showed melt processed samples to have lower half time for crystallization and higher value for the Avrami exponent. The crystallization rate of PLA was also found to depend on surface chemical composition of cellulose particles and the particle size. Influence of filler surface modification on the composite properties was studied via grafting of lactic acid and polylactic acid to cellulose particles and the effect of filler size was studied using hydrolyzed microcrystalline cellulose particles. A simple esterification reaction that required no external catalyst was used for surface modification of cellulose particles. Surface modification of cellulose particles enhanced the static and dynamic mechanical properties of the composite samples due to improvement in the PLA-cellulose compatibility that resulted in better interfacial interactions. The utility of cellulose, available from a renewable resource, as an effective reinforcement for PLA is demonstrated.
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