Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology. / Distributed Generation systems based on renewable energy sources, such as wind or solar are mostly intermittent sources, due to their dependency on the weather, whereas those based on other primary energy sources are non-intermittent. All of them are specially designed to be integrated into distribution systems, in order to improve the power demand of consumers. In the last few decades of the twentieth century, several different factors have played a key role in increasing interest in systems. Distributed Generation (DG) is gaining more and more attention worldwide as an alternative to large-scale central generating stations. The aim of this research project is to investigate the contribution of distributed generation in fault current level in a power distribution system. The simulation results indicate that DG can have a positive or negative impact, on the fault current level in distribution network systems. The DG location and size affect the fault level. The second aim of this research was to suggest a model-based method for design, and implementation of a protection scheme for power distribution systems, by establish algorithms in a hardware environment. The overcurrent relay was chosen for the model development because it is considered a simple and popular protection scheme, and it is a common scheme in relaying applications. The proposed relay model was tested for fault conditions applied on a simple power system in different scenarios. The overcurrent relay model was implemented in MATLAB/Simulink, by using MATLAB programming languages and the SimPowerSystem (SPS) Tool. MATLAB/SIMULINK software is applicable to the modelling of generation, transmission, distribution and industrial grids, and the analysis of the interactions of these grids. This software provides a library of standard electrical components or models such as transformers, machines, and transmission lines. Therefore, the modelling and simulations are executed using MATLAB/Simulink version 2014b

This dissertation deals with the economic aspect of culture and focuses on the patterns of renewable natural resources utilisation among the people living in the Matutuine District of Southern Mozambique. The study also focuses on the demography, history and socio-political organisation of the area. Against this background the study emphasises the importance of the fact that these aspects will have to be taken into account if the establishment of the planned Lubombo Transfrontier Conservation Area in the same region is to be in any way successful. This area has no conservation status at present but has been earmarked to become part of the Lumbobo Transfrontier Conservation Area. This will mean that the entire area, or a substantial part thereof, will have to be proclaimed as a protected area. In Southern Africa the establishment of conservation areas have often been coupled with the removal of people from such areas. People removed from land declared as nature conservation areas were often denied access to resources they previously utilised to survive. The research findings indicate that the local people who live in the Matutuine District of Mozambique are extremely dependent on the natural environment for their everyday survival. The vast majority of people are concentrated in small villages where they practise subsistence agriculture. Due to nutrient poor soils and other factors, the local people are not able to produce enough foodstuffs to fulfil their survival needs. Although most people own small stock, the absolute minority of people own cattle. This is largely, although not solely attributable to the turbulent history of the area, especially the effects of the Mozambican Civil War. The poverty of the people in the area increases their dependence on natural resources. Local people supplement their diets by fish, caught in the lakes and rivers in the area, and wild fruits. Due to the effects of the Civil War, most fauna in the area have been depleted but people still hunt wild animals, especially small game, for food. The local people are thus extremely dependent on the resource base of the area earmarked to become part of the Lubombo Transfrontier Conservation Area. With the information presented in this study it is possible for the planners of the Lubombo Transfrontier Conservation Area to devise a strategy that will not impair the livelihoods of the local people who live in the area, but instead accommodate their socio-economic needs in the planning process and in the eventual establishment of the Lubobo Transfrontier Conservation Area. / Dissertation (MA (Anthropology))--University of Pretoria, 2006. / Anthropology and Archaeology / Unrestricted

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.

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.

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.

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.

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.

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 No. of bitstreams: 1 Tese Pedro Antonio Ourique.pdf: 4145729 bytes, checksum: 0326f707659828778e2d95c67c9e81c9 (MD5) / Made available in DSpace on 2016-10-17T15:37:27Z (GMT). No. of bitstreams: 1 Tese Pedro Antonio Ourique.pdf: 4145729 bytes, checksum: 0326f707659828778e2d95c67c9e81c9 (MD5) 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 16 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.

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 16 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.

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 Martins_JulianaMarinhoCavalcanti_M.pdf: 986576 bytes, checksum: 2e0d46c140f02083a2c9d967645d5e63 (MD5) 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