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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Improving cost-effectiveness and mitigating risks of renewable energy requirements

Griffin, James. January 2008 (has links) (PDF)
Thesis (Ph.D.)--RAND Graduate School, 2008. / Title from title screen (viewed on Oct. 24, 2008). "This document was submitted as a dissertation in September 2008 in partial fulfillment of the requirements of the doctoral degree in public policy analysis at the Pardee RAND Graduate School." --T.p. Includes bibliographical references: p. 168-178.
42

A hydrokinetic resource assessment of the Florida Current

Unknown 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.
43

Access to electricity in sub Saharan Africa : modelling the importance and adoption of off-grid renewables

Abdul-Salam, Yakubu January 2014 (has links)
Many settlements in Sub Saharan Africa (SSA) lack access to electricity which is a necessary resource for development. Given the geography and population patterns in the region, extending national grids is economically unviable for many of the un-electrified settlements. Meanwhile the region is endowed with renewable resources which can be exploited in off-grid mode for electricity generation. This thesis examines the importance of off-grid technologies for onward electrification in the SSA region. The exercise inspires an electricity planning problem that can be analytically specified but is computationally intensive and impractical for real sized problems. Heuristic methods must therefore be used. We develop two new heuristic solution methods which draw on standard algorithms i.e. lexicographic algorithm and genetic algorithm to solve the problem. The new solution methods together with two existing heuristic algorithms in the literature are applied to a case study of Ghana. We find that the electrification schemes yielded by all four solution methods/algorithms suggest off-grid technologies, especially solar, are important for onward electrification in SSA. Locations that were assigned off-grid technologies in the algorithms mentioned above are typically rural where livelihoods are based on small scale farming. Currently, adoption of renewable resource technologies is low in these locations. We therefore develop a dynamic stochastic farm household model to examine the extent to which market failures impact self-funded investment in solar panels by farmers in rural SSA. We find that credit restrictions and risk affect solar panel investment to varying degrees. Using simulations of the policy functions, we find that the expected investment cycle for a credit constrained household in a stochastic farm income environment is 30 years if investment in solar panels is irreversible. In a reversible investment scenario, the expected investment cycle is 5 years only. Reversibility is therefore a major determinant of solar panel adoption among poor farmers.
44

The integration and analysis of intermittent sources on electricity supply systems

Grubb, M. J. January 1987 (has links)
No description available.
45

A comparative analysis of renewable energy financing models in Brazil, China, India and South Africa

Kamara, Rivhatshinyi Nicole January 2016 (has links)
Thesis submitted in fulfilment of the requirements for the degree of Master of Management in Finance & Investment in the Faculty of Commerce Law and Management Wits Business School, Johannesburg 2016 / This thesis reviewed research papers, reports, conference documents and policy documents that looked at financial models used to finance RE projects in Brazil, China, India and South Africa.The comparison between the financing models revealed the following; Both Brazil and China’s financing model is a centralised government led model which might not necessarily work in the South African context. The India decentralised model is similar to the South African model, with the exception that corporate finance is widely used in India and Project Finance in South Africa. Thus there are lessons to be learnt from each country, however no single country financing model was found to be suitable for South Africa. Accordingly, this paper therefore recommends that South Africa’s model be altered to incorporate project bonds. The use of these bonds in the current financial model will ensure that banks are able to lend to projects on short term basis; thus, managing their liquidity and their asset--liability effectively. Further, some institutional investors have shown an interest in funding projects at the construction stage, and the inclusion of project bonds would ensure that more of these investors play a role in financing projects. Key Words GDP-Gross Domestic Product; GW- Gigawatts; DoE-Department of Energy; REIPPPP- Renewable Energy Independent Power Producer Procurement Programme; BEE-Black Economic Empowerment; RE-Renewable Energy; SSA-Sub Saharan Africa; PPA-Power Purchase Agreement; FIT-Feed In Tariff; DFIDevelopment Finance Institution; MDB-Multilateral Development Bank / GR2018
46

Desenvolvimento de um método para a determinação de acilgliceróis em biodiesel utilizando cromatografia líquida de alta eficiência com detecção eletroquímica /

Ballottin, Daniela Pott Marinho. January 2011 (has links)
Orientador: Nelson Ramos Stradiotto / Banca: Marcelo Firmino de Oliveira / Banca: André Luiz dos Santos / Resumo: A alta demanda de energia no mundo atual, bem como o grande número de problemas ambientais existentes, resultam em uma crescente necessidade por novas fontes de energia, estimulando assim o interesse por fontes alternativas para os combustíveis de origem fóssil. Surge então o Biodiesel, combustível biodegradável derivado de fontes renováveis. No entanto, este biocombustível apresenta certos contaminantes que podem causar sérios danos ao motor e ao ambiente dependente de seus teores. Dentre estes, estão os acilgliceróis, remanescentes da matéria prima para a produção do biodiesel. Por exemplo, a alta concentração destes compostos aumenta a viscosidade do biocombustível, provocando depósitos nos cilindros e nas válvulas diminuindo assim a vida útil do motor. Assim, foi avaliado neste trabalho o comportamento voltamétrico do mono, di e trilinoleato de glicerina através da técnica de Redissolução Adsortiva com Voltametria AC. As curvas analíticas para o mono e trilinoleato de glicerina apresentaram linearidade de 4,0 x 10-8 a 1,6 x 10-6 mol L-1, com limites de detecção da ordem de 10-8 mol L-1. A curva analítica do dilinoleato de glicerina mostrou-se linear de 4,0 x 10-9 a 4,0 x 10-7 mol L-1, com limite de detecção da ordem de 10-9 mol L-1. Os limites de quantificação foram da ordem de 10-8 mol L-1 para o mono e o dilinoleato de glicerina e 10-7 mol L-1 para o trilinoleato de glicerina. Porém, estes não puderam ser determinados simultaneamente e, por isso, utilizou-se um método cromatográfico com detecção eletroquímica para a separação e posterior detecção destes compostos. Os acilgliceróis foram separados em coluna de fase reversa (C-18) operando em modo isocrático com fase móvel tampão fosfato pH 3,0/MeOH 60:40 (v/v) com adição de ácido ascórbico / Abstract: Currently, the high energy demand in today's world, as well as the environmental problems result in an increased need for developing renewable energy sources, thereby stimulating interest in alternative sources to fossil fuels. Then, Biodiesel comes as a biodegradable fuel derived from renewable sources. However, this biofuel has certain contaminants that can cause serious damage to the engine and the environment if they are present in inadequate amounts. Among these contaminants are the glycerides, remnants of the raw material for biodiesel production. For example, the high concentration of these compounds increases the viscosity of the biofuel causing deposits in the cylinders and valves reducing the engine lifetime. Thus, it was evaluated in this study the voltammetric behavior of glyceryl mono, di and trilinoleate by Adsorptive Stripping technique with AC voltammetry. The analytical curves for mono and tri showed linearity from 4.0 x 10-8 to 1.6 x 10-6 mol L-1, with detection limits of about 10-8 mol L-1. The analytical curve of glyceryl dilinoleate was linear from 4.0 x 10-9 to 4.0 x 10-7 mol L-1, with a detection limit of about 10-9 mol L-1. The quantification limits were in the order of 10-8 mol L-1 for mono and dilinoleate and 10-7 mol L-1 for trilinoleate. However, these could not be determined simultaneously and therefore it was developed a chromatographic method with electrochemical detection for separation and detection of these compounds. The glycerides were separated on a reversed phase column (C-18) operating in isocratic mode with mobile phase pH 3.0 phosphate buffer / MeOH 60:40 (v/v) with addition of ascorbic acid / Mestre
47

Fine Line Metallization of Silicon Heterojunction Solar Cells via Collimated Aerosol Beam Direct Write

January 2012 (has links)
Solar energy has come to the forefront as a scalable and largely underutilized renewable energy resource. The current cost of solar electricity, namely from photovoltaics, along with other logistics factors, has prevented the widespread adaptation of the technology. A key determinant of efficiency and cost for a solar cell is the current collector grid. This work presents the Collimated Aerosol Beam Direct Write (CAB-DW) system as a non-contact printing method that can achieve current collector grid finger widths of less than 10 μm which are amenable to decreasing both resistive and optical losses. The ability to produce high aspect ratio grid fingers, and deposit optimized grid structures on high efficiency SHJ solar cells using silver nanoparticle inks is also demonstrated. A decrease in shadowing and via profile modification of the grid fingers is presented, along with a study of aging and degradation of electrical properties within silver nanoparticle inks.
48

O uso do carvão vegetal nos Pólos Guseiros: implicações sociais, ambientais e econômicas / The use of charcoal pig iron at the Poles: social, environmental and economic

Luczynski, Estanislau 25 August 1995 (has links)
Este trabalho aborda diversas implicações de ordem tecnológica, ambiental e social relacionados ao uso de carvão vegetal nos pólos guseiros. Através de coleta de dados em publicações técnicas, visitas a centros de tecnologia guseira e entrevistas com especialistas da área, foram levantadas as informações que serviram de base à elaboração deste trabalho. A análise e interpretação dos resultados obtidos mostram que a manutenção da produção de ferro-gusa depende do contínuo fornecimento de carvão vegetal, como termo-redutor de boa capacidade calorífica, preço baixo e fácil acesso. Todavia, nas condições atuais, o suprimento de carvão vegetal à indústria está relacionado à exploração intensiva de florestas nativas e uma correspondente falta de áreas reflorestadas capazes de suprir a demanda de lenha para carvoejamento. Além do carvão vegetal, outros insumos também podem ser usados na redução do minério de ferro: o gás natural (na produção integrada de aço) o carvão de coco de babaçu, o carvão vegetal de espécies nativas da Amazônia e mesmo o carvão mineral. Estes insumos, entretanto, apresentam problemas ainda não totalmente quantificados, como suprimento, tecnologia adequada de uso e custos de exploração. O uso intensivo de carvão vegetal se baseia na existência de uma rede de carvoejadores e fornos, que operam num ritmo de trabalho intenso (às vezes cerca de quinze horas por dia), baixa remuneração por madeira carvoejada (meio dólar por metro cúbico de carvão vegetal) e falta de seguridade social. De modo geral, os produtos de gusa pouco consideram o uso de carvão de florestas plantadas, pois admitem que um carvão de maior custo, constituir-se-ia em ameaça à própria continuação da produção de ferro-gusa. / The aim of this work is to discuss implications technological, environmentally and social limitations of the pig-iron´s production using charcoal. Through technical papers, technical visits to research centers and interview with experts, a data basis was collected to produce this work. The analysis of data showed that: the continuity of pig-iron making depends on continuos supply of charcoal, at low cost, with good heat capacity, and with easy acess. However, under current conditions, the charcoal supply to industry is depending of a intensive exploration of native forest. At the same time, there is a lack of land suitablefor reforestation to provide wood to renewable charcoal making. Nevertheless, there are several resources that can be used to reduce the iron ore: charcoal of babassu coconut, charcoal of native amazonic trees, natural gas (integrated plants) and even coal. Some of them are candidates to replace the charcoal, but further technological, infrastructural and economic developments are still required. The intensive utilization of charcoal by siderurgy is based in a network of kilns and charcoal makers working under extreme conditions (indeed, some work fifteen hours per day), they have no social security and extremely low wages (some receive only half a dollar per cubic metre of charcoal). In general, pig-iron´s makers do not consider the use of charcoal from forested wood, because its higher cost may challenge the viability of pig-iron production.
49

A study of regularities associated with biochemical processes and renewable energy resources

Patel, Snehal A January 2011 (has links)
Typescript (photocopy). / Digitized by Kansas Correctional Industries
50

Nanofluidics: Fundamentals and Applications in Energy Conversion

Liu, Ling January 2010 (has links)
As a nonwetting liquid is forced to invade the cavities of nanoporous materials, the liquid-solid interfacial tension and the internal friction over the ultra-large specific surface area (usually billions of times larger than that of bulk materials) can lead to a nanoporous energy absorption system (or, composite) of unprecedented performance. Meanwhile, while functional liquids, e.g. electrolytes, are confined inside the nanopores, impressive mechanical-to-electrical and thermal-to-electrical effects have been demonstrated, thus making the nanoporous composite a promising candidate for harvesting/scavenging energy from various environmental energy sources, including low grade heat, vibrations, and human motion. Moreover, by taking advantage of the inverse process of the energy absorption/harvesting, thermally/electrically controllable actuators can be designed with simultaneous volume memory characteristics and large mechanical energy output. In light of all these attractive functionalities, the nanoporous composite becomes a very promising building block for developing the next-generation multifunctional (self-powered, protective and adaptive) structures and systems, with wide potential consumer, military, and national security applications. In essence, all the functionalities of the proposed nanofluidic energy conversion system are governed by nanofluidics , namely, the behavior of liquid molecules and ions when confined in ultra-small nanopores. Nanofluidics is an emerging research frontier where solid mechanics and fluid mechanics meet at the nanoscale. The complex interactions between liquid molecules/ions and solid atoms at the nanointerface, as well as the unique structural, thermal and electrical characteristics of fluids confined in nanocavities collectively represent an outstanding challenge in physical science. A thorough understanding of the science of nanofluids, in particular the detailed molecular mechanisms as well as the roles of various material and system parameters, does not only underpin the development and optimization of the aforementioned nanofluidic energy conversion system, but it also have broad impact on a number of other areas including environmental engineering, chemical engineering, bioengineering, and energy engineering, etc. This dissertation carries out a systematic computational study to explore the fundamental nanofluidic infiltration and transport mechanisms, as well as the thermal and electrical characteristics of the solid-liquid interface. New physical models describing the unique nanofluidic phenomena will be established, where critical parameters, such as the surface tension, contact angle, and viscosity, will be reinvestigated at the nanoscale. The effects of various material and system parameters, such as the solid phase, liquid phase, pore size and pore geometry, as well as the external thermal, electrical and mechanical loads, etc., will be systematically investigated and bridged with the nanofluidic energy conversion processes. The energy conversion efficiencies under various conditions will be evaluated via a synergy between simulation and experiment. Reverse analysis based on the revealed principles can guide the optimization of the various material and system parameters, which potentially may contribute to the design of highly efficient and sustainable nanofluidic energy conversion devices. Besides the direct impact on the nanofluidic energy conversion, the study is also directly relevant to biological conduction and environmental sustainability, in both of which infiltration and transport play important roles.

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