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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.
11

Evaluation of generator circuit breaker applications / J.F. Fourie.

Fourie, Johannes Frederick January 2010 (has links)
The use of generator circuit breakers in power stations was investigated and evaluated. A feasibility study to determine if the additional capital cost required, when using a generator circuit breaker in a power station could be justified by the advantages it provides. The background to the study is provided through a technology and literature survey. Included in the technology review and the literature study is information on interruption mediums, the historic developments of circuit breakers and generator circuit breaker application theory. This data was used to determine the practicality of using a specific interruption medium within a generator circuit breaker application. The requirements of generator circuit breakers were determined and used to evaluate the interruption mediums in question. To ensure practical results, commonly used layouts were used to determine the effect of using a generator circuit breaker on the reliability, availability and the mean time to repair of a power station electrical distribution layout. Furthermore, the effect of the protection on the generator and generator transformer was evaluated. It was found that increased selectivity of the protection system by using a generator circuit breaker limits the extent of equipment damage in case of failure. Practical layouts were used to determine the effect on reliability. The analysis was conducted using assumed values of operational costs to determine the cost incurred through the change in reliability of the power station. By adding a generator circuit breaker, the station transformer and associated equipment is regarded as back-up or redundant equipment. This increases the reliability of the power station dramatically and limits the risk of income lost due to failures. The full evaluation included the estimation of the capital investment costs and the impact that the additional cost has on the operational requirements of a power station. The study determined that the capital cost required to use a generator circuit breaker results in no additional income for a power station. Through the increased protection, higher availability and the possible omission of power station ancillary equipment, the use of generator circuit breakers will result in more power being delivered and more income generated by a power station. The study proved that the generator circuit breaker is a critical part of a power station layout and is a necessary capital requirement to ensure the sustainability of the power station. / Thesis (M.Ing. (Electrical and Electronic Engineering))--North-West University, Potchefstroom Campus, 2010.
12

What risks in whose risk society? : an assessment of what effect, if any, the historic and contemporary socio-economic conditions and expectations of the community of Sands End, Fulham, London, had on the character and dynamics of the 1983-1984 debate over the decontamination and demolition of Fulham Power Station

Bennett, Simon Ashley January 1996 (has links)
The thesis discusses the mediating role of socioeconomic factors in risk debates through an examination of the decontamination and demolition of Fulham Power Station in 1983-1984. The power station was built between the wars by and for the people of Fulham. Located on the Thames in the neighbourhood of Sands End, it generated electricity and provided employment until 1978, when it was sold to a property development company. During the decontamination, a quantity of asbestos was released into the environment. A protest group was formed to secure better standards of work at the site. The group never had more than a dozen active members. All the members were middle-class. At the time of the decontamination and demolition, Sands End was a poor neighbourhood. A majority of the local population faced many 'social' as well as environmental hazards. Amongst these were sub-standard housing, unemployment, under-employment, low wages, inadequate work and educational skills and crime. The thesis discusses whether the neighbourhood's socioeconomic problems had any bearing on the character and dynamics of the power station debate. It suggests that the social geography and economic status of Sands End had two major effects on the debate. Firstly, gentrification provided the neighbourhood with a (small) middle-class constituency receptive to issues of environmental risk, such as the long-term health implications of airborne asbestos dust. Secondly, the neighbourhood's pressing social and economic problems mitigated against a wider involvement in the campaign. Most residents were too preoccupied with meeting their social and economic needs to become actively involved. The thesis also suggests that the population's experience of Fulham Power Station as a source of 'convenient' electrical power, employment and civic pride may have made it difficult for those native to Sands End to accept the activists' construction of the power station as a source of danger.
13

Sledování dlouhodobých změn a hodnocení vývojových trendů krajinného prostředí ovlivněném výstavbou JETE / Pursuit secular changes and evaluation of trends in country around JETE and influence JETE over country

POLÁČKOVÁ, Stanislava January 2008 (has links)
The content in my graduation theses is characteristic of villages and poeple in outbuildings , which disappeared by the development JETE. I wrote about trend in number of houses and poeple in the time 1869 {--} 2001 in comparision with Southbohemia region, district around Č. Budějovice, city Týn n. Vltavou and village Temelín, which is nearly JETE. People compare target the age, nationality and economy power in the country around JETE. I wanted to desribe structure of settled outbuildings. The trend of the country target the farmland, status quo around JETE, i.c. reconstruction of castle Býšov in distillery, characteristic park of castle, valuation of landscape and coefficient ecological stability.
14

Common ground : a landscape shared between man, his productions and nature

Joubert, Marise January 2015 (has links)
This dissertation investigates how a productive landscape can increase the carrying capacity of the land, by analysing and responding to the existing site and a proposed post-industrial development of the site done in 2010. The aim is to effectively communicate the influence of man’s highly consumerist nature on resources and the ecology on the user group. The chosen site is located in the highdensity urban context of Pretoria West, Tshwane, South Africa. The motivation of this dissertation is for the landscape to be the synergy between the existing productive entities. The strategy was to design holistically, with the objective being to include the larger systems at play. Systemic thinking, in terms of production, increases resources and the variety of resources’ deliverability. The only way that a productive landscape can be resilient is to instil positive meaning in the user and, consequently, indefinite stewardship. To achieve resilience, biophilic urban design guidelines were followed to have a positive psychological effect on the user. This dissertation aims to re-address age-old theories, such as biophillia and the “Web of Life”, as crucial guidelines to inform interventions for the current, real time, global and African issues relating to increasing resource demands. / Dissertation (ML(Prof))--University of Pretoria, 2015. / Architecture / ML(Prof) / Unrestricted
15

Akumulace elektrické energie z obnovitelných zdrojů / Accumulation of electricity from renewable sources

Dědek, Dušan January 2008 (has links)
This work is specialized on problems accumulation electricity power from renewable sources and production electricity power from renewable sources for select object. First part describes renewable sources and their use in our conditions. Second part is specialized on accumulators specific for renewable sources. Third part compare to production electricity power from photovoltaic power station and windy power station and their combination for select object. Further accumulation these select sources. Final fourth part describe about their comparison from position how of technical so economic.
16

Management model to optimise the use of reverse osmosis brine to backwash ultra-filtration systems at Medupi power station / Frederik Jacobus Fourie

Fourie, Frederik Jacobus January 2014 (has links)
According to the Department of Water Affairs (DWAF, 2004 p.15), South Africa’s water resources are scarce and extremely limited and much of this precious resource is utilised and consumed in our industries. Treatment and re-use of effluent generated is, in some cases, preferred over use of alternate water resources (Du Plessis, 2008 p.3). The volume of effluent generated in treatment processes like ultra-filtration (UF) and reverse osmosis (RO) units is determined by the feed water quality, with high water loss through effluent generation at poor feed water quality. Current UF and RO applications require an increased UF production capacity due to the use of UF filtrate for periodic backwashing of the UF membrane units. This results in loss of water and decreases overall recovery. The need therefore exists to increase the overall recovery of product water from the raw water stream by reducing the amount of effluent generated. This would be possible to achieve by using RO brine to backwash the UF unit. The study was conducted to provide a modelling tool, assisting management to optimise the use of RO brine as backwash water on the UF system at the Medupi power station. The secondary objective of this study was the development of a modelling tool that can be used for other projects, new or existing, as a measure and indication of the usability of RO brine as backwash water on UF systems. By successfully applying this newly developed model, the viability of utilising the RO brine as backwash water for the UF was investigated. This modification would lead to utilizing smaller UF units than previously envisioned, which in turn leads to reducing capital cost with 11.07% and operating expenditure with 9.98% at the Medupi power station. This also has a positive environmental impact by reducing the amount of raw water used monthly by 10.34% (108 000 m3/month). / MIng (Development and Management Engineering), North-West University, Potchefstroom Campus, 2014
17

Investigating the long-term effects of air pollution on soil properties in the vicinity of the Arnot power station

Reid, Joanne Lynne 23 May 2008 (has links)
A study was conducted in 2006 to investigate the long-term effects of air pollution on soil properties in the vicinity of the Arnot power station, Mpumalanga, South Africa. Fifteen sites were re-sampled and the soil chemical properties compared to baseline data gathered in 1996, resulting in a ten year period after which changes in soil properties were investigated. A spatial gradient was incorporated into the study in order to better understand the deposition of pollutants with increasing distance from the power station. The study indicates that long-term acidic deposition has led to detectable changes in soil chemical properties. Three chemical properties, namely the concentrations of calcium and magnesium in both the topsoils and the subsoils, as well as the effective cation exchange capacity in the subsoils showed a significant increase since 1996. However, five soil chemical properties, namely soil pH (K2SO4), the concentration of hydrogen and aluminium and total sulphur in both the topsoils and the subsoils, as well as extractable sulphate in the topsoils and soluble sulphate in the subsoils, all show that the soils have become more acidic over the ten years. The acidic components in the soil override the basic components, as shown by the ratio of basic cations to acidic cations in the soils. The spatial gradient generally indicates that at approximately 8 km from the power station, there is a decrease in the concentration of acidic soil properties and one explanation for this may be a reduction in the acidic components of atmospheric deposition at this site. However, this needs further investigation. Two significant relationships with distance were found, namely a significant negative relationship with soluble sulphate and a significant positive relationship with acid neutralising capacity. This research will form part of a database for other long-term monitoring programmes and will allow data to be compared to other data from this area of research. It will also provide information to important industry leaders such as Eskom.
18

A Tradição Tupiguarani na Bacia do Alto Tocantins / The Tupiguarani Tradition in the Bay of the Upper Tocantins

Pontim, Rute de Lima 16 September 2011 (has links)
O estudo apresenta uma análise sobre os sítios arqueológicos filiados à Tradição Tupiguarani e da cultura material deles decorrentes, de modo a favorecer uma discussão sobre os elementos constituintes dessa filiação cultural na Bacia do Alto Tocantins. Os trabalhos foram executados no âmbito de projetos de salvamento arqueológico, parte integrante da modalidade da pesquisa arqueológica de contrato, realizados pelo Laboratório de Arqueologia do Museu Antropológico da Universidade Federal de Goiás. Os registros arqueológicos foram identificados na área dos empreendimentos hidrelétricos da UHE Serra da Mesa e UHE Cana Brava, localizados na Bacia do Alto Tocantins, região norte do estado de Goiás. O trabalho tem como objetivo relatar as características observadas na constituição do processo de ocupação da área pela Tradição Tupiguarani, mesmo que seus assentamentos sejam significativamente reduzidos neste território, cuja predominância está relacionada aos grupos filiados às Tradições Aratu e Uru. O propósito não é contestar a existência breve ou perene desses grupos na região, se existiram apenas como circulantes de uma rota de migração, mas buscar compreender a partir do cenário arqueológico encontrado, manifestações que configurem a dinâmica de ocupação pelos grupos ceramistas pré-coloniais relacionados à Tradição Tupiguarani. / This study shows an analysis of the archaeological sites related to the Tupiguarani tradition and the material culture arose from it, in a way to enhance a discussion on the principles of such cultural relationship in the Bay of the Upper Tocantins. The work was done in the scope of projects of archaeological rescue, integrating part of the feature of the archaeological research of contract, realized by the Archaeology Laboratory of the Anthropological Museum of the Federal University of Goiás. The archaeological records were identified in the area of the hydroelectric venture of the Hydroelectric Power Station of Serra da Mesa and the Hydroelectric Power Station of Cana Brava, located in the Bay of Upper Tocantins in the north of the Goiás State. The objective of the work is to report the characteristics observed in the constitution of the occupation process of the area by the Tupiguarani Tradition, even though its settlement was quite reduced in this territory, which was predominantly related to the Aratu and Uru Traditions. The aim is not to contest the brief or perennial existence of these groups in the area, if their settlement there was just part of a migratory movement, but to try to understand the manifestation that represents the dynamic of the occupation by the pre-colonial ceramist groups related to the Tupiguarani Tradition according to the archaeological scenery found.
19

Licenciamento ambiental no Brasil sob a perspectiva da modernização ecológica. / Environmental Licensing in Brazil: the Ecological Modernization perspective

Souza, Alexandre do Nascimento 03 April 2009 (has links)
O Licenciamento ambiental é um dos instrumentos da Política Nacional de Meio Ambiente, estabelecida pela lei 6.938 de 1981. Nos últimos 30 anos, o país passou por inúmeras transformações econômicas, políticas e sociais. No cenário de grande potencial hidrelétrico do país, demanda crescente por energia, fortalecimento e consolidação da legislação e do sistema de gestão ambiental, participação de novos atores econômicos interessados em prover a expansão do parque de geração de energia, maior participação dos movimentos sociais na esfera pública e uma memória não muito distante de graves problemas socioambientais ocasionados pela construção de hidrelétricas; é que se dão os conflitos que perpassam todo o processo de licenciamento ambiental de hidrelétricas e do qual se ocupa essa dissertação. Entre os anos de 2004 e 2008, muitos atores econômicos e sociais envolvidos com a temática do licenciamento ambiental no país se posicionaram publicamente, sobretudo a respeito dos conflitos relacionados à concessão das licenças ambientais para empreendimentos hidrelétricos. A reflexão sociológica a qual se propôs este projeto de pesquisa utiliza a Teoria da Modernização Ecológica como instrumental teórico e busca entender o estado da arte do licenciamento ambiental de hidrelétricas no Brasil. / The Environmental license is one of the tools of the National Environmental Policy, established by the law 6.938 of 1981. Over the past 30 years, the country has had lots of economical, political and social changes. The socio-environmental conflicts that permeate the environmental licensing process of UHEs, which constitute the subject of this dissertation, happen in a context characterized by the great hydroelectric potential of the country, the increasing demand for energy, the strengthening and consolidation of the legislation and of the environmental management system, the growing participation of the social movements in the public sphere, a recent memory of socio-environmental problems resulting from the construction of hydroelectric power stations and the participation of new economic agents interested in promoting the expansion of the energy generation park. Between 2004 and 2008, many economical and social agents that were involved with environmental licensing subjects in Brazil publicly expressed their positions, mainly in relation to the conflicts related to environmental license concession for hydroelectric enterprises. The sociological analysis of this research project uses the Ecological Modernization Theory as a theoretical instrument. It also aims to understand the environmental licensing process for hydroelectric power stations in Brazil.
20

As usinas hidrelétricas e seus impactos : os aspectos socioambientais e econômicos do reassentamento rural de Rosana-Euclides da Cunha Paulista /

Mendes, Noeli Aparecida Serafim. January 2005 (has links)
Neste trabalho, realizamos um estudo sobre pequenos produtores do Reassentamento Rural de Rosana, localizado no município do Euclides da Cunha Paulista. Esse reassentamento é formado em sua maioria de pequenos produtores, antes ilhéus e ribeirinhos. Com a construção da usina hidrelétrica de Rosana, no Rio Paranapanema, eles foram realocados para o reassentamento Rural. A pesquisa teve como objetivo compreender os aspectos socioambientais e econômicos, bem como identificar como foram consideradas as variáveis ambientais no período de implantação do reassentamento e, posteriormente, quais foram os possíveis cuidados com relação às questões ambientais tanto por parte dos reassentados quanto pelo poder público. Além disso, verificamos as perspectivas futuras de permanência desses reassentados. Na pesquisa, constatamos que no Reassentamento Rural de Rosana, a principal atividade econômica é a pecuária bovina. Os reassentados complementam sua renda com a aposentadoria e, também, com o trabalho assalariado e temporário na Destilaria Alcídia e na vizinhança. A agrovila passou a exercer uma outra função: a presença de estabelecimentos comerciais, de serviços de saúde e educação tanto para os seus moradores como para os habitantes dos assentamentos vizinhos e residências dos trabalhadores da Destilaria de Álcool Alcídia. Com relação às questões ambientais, verificamos que não foram consideradas desde sua implantação as variáveis ambientais. Há a ausência dos órgãos públicos no que se refere a essas questões e, também, da assistência técnica, o que poderá comprometer as perspectivas futuras dos reassentados. Daí a necessidade de políticas públicas relacionadas ao crédito agrícola e à assistência técnica, que favoreçam a pequena produção familiar, melhorando assim a condição econômica e social, para garantir a permanência dos reassentados. / In this paper, we have carried on a study on small-scale producers of the Rural Resettlement in Rosana, which is located in Euclides da Cunha Paulista County. Most of this resettlement is formed by small-scale producers, which were formely islanders and riverside in habitants. These were moved on to the resettlement,in view of the construction of the Rosana hydroelectric power station in the Paranapanema River. This research aims to understand the socio-envionmental and economic aspects, as well as to identifify how environmental variables were considered in the implant period of resettlement, and, later on, which was the possible care referring to environmental matters from both the resettled people and the public power. Besides, we have verified these future perspectives of the resettled people's staying. In the research, we have observed that the main economic activity is the cattle husbandry in the Rosana Rural Resettlement. The resettled people complement their income with their retirement salaries, and with temporay - job wages at the Alcidia Distillery and nearby as well. The agrovillage happened to exercise another function: the presence of stores, health and education services for both its own neighborhood's inhabitants as well as for the Alcidia Alcohol Distillery workers. Regarding the environmental matters, we have verified that the environmental variables haven't been considered since its implant. There is an absence of public agencies referring to those matters, and to technical assistance as well, which could compromise the future perspectives of the resettled people. Therefore, there is a lack of public policies in relation to agricultural credit and technical assistance, which, if implemented, would favor the family's small-scale production, in order to improve the economical and social conditions, guaranteeing the resettled people's staying. / Orientador: Rosângela Aparecida de Medeiros Hespanhol / Coorientador: Célia Maria Santos Vieira de Medeiros / Banca: Antonio César Leal / Banca: Elpídio Serra / Mestre

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