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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.
71

Die invloed van versteurde inlaatvloeipatrone op aksiaalwaaiers

Visser, J. G. J. 12 1900 (has links)
Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering. / Thesis (MEng)--Stellenbosch University, 1990. / ENGLISH ABSTRACT: The causes of disturbances in the flow patterns at the inlets of axial flow fans that are used in mechanical draft cooling towers and the effects of these disturbances on the fans, were investigated. A scale model of a part of a mechanical draft cooling tower used at a power station was built for the purpose of this study. In the cooling tower the axial flow fans are arranged in a matrix configuration. It was noted from the scale model that the boundary fan was subjected to the worst inlet disturbances and this had an adverse effect on the flow it produced. Geometric alterations like the use of guide vanes and rounded inlets improved the flow through the boundary fan considerably. It was found that the performance of the fans is a function of the number of fans used and the elevation of the fans. Several tests to determine the performance of the cooling tower confirmed the results obtained from the experiments on the scale model. It was also found that the speed and direction of the prevailing wind have a significant effect on the cooling tower. Experiments to investigate the effects of cross-flow at the inlet of a fan indicated an increased flow through the fan at low cross-flow velocities and that the flow decreased at high cross-flow velocities. / AFRIKAANSE OPSOMMING: Die invloed en oorsake van versteurde inlaatvloeipatrone op aksiaalwaaiers wat in meganiese-trek koeltorings gebruik word is ondersoek. 'n Skaaimodel van 'n deel van 'n meganiese-trek koeltoring wat by 'n kragstasie gebruik word is gebou vir die doel van die studie. Die aksiaalwaaiers wat in die koeltoring gebruik word is in 'n matrikskonfigurasie gerangskik. Vanaf die skaalmodel is waargeneem dat die randwaaier die ergste versteuring by die inlaat ervaar, en gevolglik minder vloei as die res van die waaiers in die opstelling lewer. Die vloei deur die randwaaier is verbeter deur verskillende geometriese wysigings soos leilemme en inlaatafrondings aan te bring. Daar is gevind dat die werking van die waaiers in die opstelling 'n funksie van die hoeveelheid waaiers asook die grondvryhoogte is. Om die werking van die koeltoring te bepaal is verskillende toetse daarop uitgevoer. Die resultate het die geldigheid van die skaalmodel bevestig. Daar is ook gevind dat die heersende windsterkte en rigting 'n definitiewe invloed op die koeltoring uitoefen. Die invloed van 'n dwarsvloei by die inlaat van 'n enkele waaier is ook eksperimenteel ondersoek. Die resultate toon dat daar 'n vermeerdering in vloei deur die waaier by lae dwarsvloeisnelhede plaasvind. Hoë dwarsvloeisnelhede veroorsaak egter 'n vermindering in vloei.
72

The fish populations of the Lower Forth Estuary, including the environmental impact of cooling water extraction

Greenwood, M. F. D. January 2001 (has links)
The present study investigated the fish populations of the lower Forth Estuary, east Scotland. Cooling water extraction by the 2400 MW Longannet Power Station (LPS) inevitably removes a certain quantity of fish from the estuary, all of which experience mortality. The present study employed a sampling regime of greater intensity than previous studies to investigate the extent of mortalities from January 1999 - December 2000. Collections of fish impinged on intake screens were made eight times monthly, at LW or HW of spring or neap tides during the day or by night. Marine species dominated the assemblage of fish collected, with sprat, herring, and whiting contributing > 80% of total abundance. Sprat was twice as abundant as herring in 1999, while the proportions were very similar in 2000. Total abundance of all species collected in 1999 was estimated at 1. 09 x 107, while the value of 3.29 x 107 in 2000 was three times larger. These figures were the largest recorded among British estuarine and marine power stations, but were precisely the correct order based on an exponential relationship between total impingement and water abstraction rate established from data from other locations. Validation of the estimated total biomass of fish removed was given by comparison with the known total mass of all materials disposed to landfill. Statistical analysis of impingement data showed that tidal range and season were the most important environmental variables influencing the rate of removal of fish from the estuary. That light was not significant for most species is attributed to high levels of turbidity and the resulting low visibility by day and night. Demersal and benthic fish abundances collected from 1982 - 2000 in 30 annual trawls at three sites in the mid-lower Forth Estuary were analysed. Species tended to be present in greatest abundance at the most seaward of the sites. Patterns of seasonal abundance reflected those observed in the impingement study at LPS, and catches tended to be greatest at L W. Total species richness showed no significant trend over time, whilst total annual abundance of fish captured in trawls showed a significant negative trend. This was largely due to significant declines in the two most abundant species, namely whiting and eel pout, attributable in the latter case to increasing temperatures. Changes in the ichthyofaunal composition were largely driven by whiting, eel pout, cod and plaice. Eight of ten common species showed no significant trend in abundance over the length of the time series, suggesting them to perhaps be at equilibrium densities. Quantities of commercially fished species above minimum landing size limits that were removed by LPS were very low, and restricted to herring and occasional whiting. The quantity of juveniles that could have recruited into the fished populations was expressed as equivalent adults. The values were larger than any previously reported in the UK, primarily due to the quantities of juvenile fish impinged being greater than at any other British power station, and the importance of the Forth as a nursery area for marine species. It was concluded that LPS is the dominant UK power station in terms of magnitude of impingement losses. It may be prudent to consider a precautionary approach to mitigate losses, and to this end options for reduction of the magnitude of impingement are discussed.
73

Comparação de indicadores de eficiência energética e exergética em duas indústrias do setor sucroalcooleiro / Comparison of indicatives of energetic and exergetic efficiency in two industries of sugar-alcohol sector

Schirmer, Florian 27 June 2006 (has links)
Made available in DSpace on 2017-07-10T19:25:07Z (GMT). No. of bitstreams: 1 Florian Schirmer.pdf: 2016231 bytes, checksum: 57aa2561433d1c4c0448c03930721ca7 (MD5) Previous issue date: 2006-06-27 / This work has an objective to study and to compare energetic and exergetic indicatives of two sugar and alcohol sector industry. The study was realized in 2005 harvest time at both industries. It was opted in doing the experiment collecting datas from individual boilers in each industry, quantity of ground cane, properties of cane and bagasse, quantity of energy involved in process per sectors, commercialized energy with the concession of each region and characteristics of each equipment involved in the process. The data were collected from respective department data-bank and through interviews with the responsibles for each sector, being the work based on studies done by diary and monthly average from collected data. The results pointed that each analyzed industry has different indicators for each studied data. The study states that both factories need more efficient equipments. And exergetic indicators presented results next to the studies done to Vale do Rosário Factory and mentioned on this work. / Este trabalho teve como objetivo estudar e comparar indicativos energéticos e exergéticos de duas indústrias do setor sucroalcooleiro. O estudo foi realizado no período de safra 2005 em ambas as indústrias. Optou-se em se fazer o experimento utilizando-se dados das caldeiras individualmente em cada indústria, quantidade de cana moída, propriedades da cana e do bagaço, quantidade de energia envolvida no processo por setores, energia comercializada com a concessionária de cada região e características de cada equipamento envolvido no processo. Os dados foram colhidos dos bancos de dados dos respectivos departamentos e por meio de entrevistas com os responsáveis de cada setor, sendo o trabalho baseado em estudos feitos pelas médias diárias e mensais dos dados coletados. Os resultados apontaram que cada indústria analisada tem indicadores diferentes para cada dado estudado. O estudo comprova que ambas as usinas necessitam de equipamentos mais eficientes. Já os indicadores exergéticos apresentaram resultados muito próximos aos do estudo feito para a Usina Vale do Rosário e mencionados neste trabalho.
74

Comparação de indicadores de eficiência energética e exergética em duas indústrias do setor sucroalcooleiro / Comparison of indicatives of energetic and exergetic efficiency in two industries of sugar-alcohol sector

Schirmer, Florian 27 June 2006 (has links)
Made available in DSpace on 2017-05-12T14:48:29Z (GMT). No. of bitstreams: 1 Florian Schirmer.pdf: 2016231 bytes, checksum: 57aa2561433d1c4c0448c03930721ca7 (MD5) Previous issue date: 2006-06-27 / This work has an objective to study and to compare energetic and exergetic indicatives of two sugar and alcohol sector industry. The study was realized in 2005 harvest time at both industries. It was opted in doing the experiment collecting datas from individual boilers in each industry, quantity of ground cane, properties of cane and bagasse, quantity of energy involved in process per sectors, commercialized energy with the concession of each region and characteristics of each equipment involved in the process. The data were collected from respective department data-bank and through interviews with the responsibles for each sector, being the work based on studies done by diary and monthly average from collected data. The results pointed that each analyzed industry has different indicators for each studied data. The study states that both factories need more efficient equipments. And exergetic indicators presented results next to the studies done to Vale do Rosário Factory and mentioned on this work. / Este trabalho teve como objetivo estudar e comparar indicativos energéticos e exergéticos de duas indústrias do setor sucroalcooleiro. O estudo foi realizado no período de safra 2005 em ambas as indústrias. Optou-se em se fazer o experimento utilizando-se dados das caldeiras individualmente em cada indústria, quantidade de cana moída, propriedades da cana e do bagaço, quantidade de energia envolvida no processo por setores, energia comercializada com a concessionária de cada região e características de cada equipamento envolvido no processo. Os dados foram colhidos dos bancos de dados dos respectivos departamentos e por meio de entrevistas com os responsáveis de cada setor, sendo o trabalho baseado em estudos feitos pelas médias diárias e mensais dos dados coletados. Os resultados apontaram que cada indústria analisada tem indicadores diferentes para cada dado estudado. O estudo comprova que ambas as usinas necessitam de equipamentos mais eficientes. Já os indicadores exergéticos apresentaram resultados muito próximos aos do estudo feito para a Usina Vale do Rosário e mencionados neste trabalho.
75

The planning of the Castle Peak 'B' power station project /

Lam, Wan-chung, Jimmy. January 1900 (has links)
Thesis (M.B.A.)--University of Hong Kong, 1983.
76

Alternatyvios energijos plėtros efektyvumo didinimas / Increase of development efficiency of alternative energy

Simanavičius, Nerijus 03 July 2009 (has links)
Šio darbo tikslas – išnagrinėti veiksnius, darančius įtaką alternatyvios energetikos plėtros efektyvumui Lietuvoje ir sukurti modelį šiai problemai spręsti, remiantis atliktais ekonometriniais ir realaus projekto skaičiavimais. Pagrindinės sprendžiamos problemos yra susijusios su silpnais bendradarbiavimo ryšiais tarp politikos, verslo ir mokslo sričių. Neefektyvus finansavimas energetinių projektų, neracionalus piliečių motyvavimas dėl alternatyvios energijos (AE) privalumų ir ilgas atsipirkimo laikas, suteikia neekonomiško verslo „šešėlį“. Viena iš svarbiausių darbo dalių yra realaus energetinio projekto parengimas. Atlikus tyrimą nustatyta, kad norint gyvenamajam namui įrengti vėjo jėgainę, bei šilumos siurblį, reikia 181 000 Lt pradinių investicijų, o diskontuotas projekto atsipirkimo laikas sudarytų beveik 18 metų. Kad tokie projektai atsipirktų daug anksčiau ir pradinės investicijos būtų mažesnės, buvo parengtas alternatyvios energetikos (toliau – AE) plėtros efektyvumo modelis, kuris akcentuoja verslo, mokslo ir politikos sinergijos būtinumą. Darbo apimtis – 74 p. teksto be priedų, 39 iliustr., 23 lent., 70 literatūros šaltinių. Atskirai pridedami darbo priedai. / This work main point – explore alternative energy developmental efficiency influencing forces in Lithuania, and make a model, to solve this problem, with reference, econometric and real project counts. The main solving problems are associated with week relationship between policy, business and science. Non effective sponsorship of energetic projects, non rational motivation of citizens in AE advantages, and long payback, gives non economical business „shadow“. The one of most important part of this work is preparation of energetic project. The main results maintaining that, if we want put a wind mill and thermal pump in individual house, we need at least 181 000 Lt, start – up investments and discounted payback will be reached about 18 years. That projects, like this will be payback earlier and start – up investment will be smaller was prepared alternative energy developmental model, witch emphasizes business, science and policy synergy necessity. Thesis consist of: 74 p. text without appendixes, 39 pictures, 23 tables, 70 bibliographical entries. Appendixes included.
77

Nigerian coal power stations : their future in the light of global warming / E.N. Eziukwu

Eziukwu, Emenike Nduaka January 2008 (has links)
Nigeria is presently being faced with a growing electricity demand problem following its population growth rate. The total installed capacity is far less than the current demand for electricity supply. As a way of bridging out this supply gap, the federal government is mobilizing all of its potential energy options. Coal is widely used for power generation in many countries. But today, the continued usage of coal for power generation is being challenged by the disturbing global warming phenomenon. This is due to the quantity of uncontrolled carbon dioxide emission from traditional coal-fired power plants. The aim of this dissertation is to critically analyse the future of the Nigerian coal power stations following the need to do carbon dioxide emission control necessary for ensuring a sustainable environment. Achieving this aim entails the appraisal of environmental regulation standards and cost structures of carbon dioxide (C02) emission reduction options for the coal power stations. Controlling carbon dioxide emission from existing coal power stations requires retrofit system that captures and effectively sequestrates the captured CO2. The cost and performance effect of the CO2 retrofit system on the existing power plant can be simulated with standard computer software models. In this study the lECM-cs computer modelling tool for power plants was used in determining the cost and performance impacts of applying an Amine-based C02 capture system to the Oji river power station in Nigeria. With the lECM-cs model, it was established that reducing C02 emission imposes an additional cost on the power plant which increases the unit cost of electricity generated. This additional cost index requires economic justification for its acceptance. This is due to the need to demonstrate its viability judging from the cost of electricity generated from other sources in the Nigerian economy. For the Oji river case, the station is old and requires extensive renovation. This causes a cost escalation over and above the cost associated with the CO2 sequestration system. As such, Oji coal power station does not have an economic future if C02 emission sequestration becomes obligatory. The future of coal power stations in Nigeria can be considered from two scenarios: one where the current national environmental standard is retained and another where it is revised. The revision classifies CO2 as a pollutant which makes its emission reduction imperative for coal power plants. Under the current standard, building modern large capacity pulverized coal-fired power plants with improved steam cycles should be encouraged. But with the review of the national standard, the focus should be on building new large capacity coal power stations with integrated CO2 emission control. This will ensure an environmentally friendly future for coal power stations in Nigeria. / Thesis (M.Ing. (Development and Management Engineering))--North-West University, Potchefstroom Campus, 2009.
78

Nigerian coal power stations : their future in the light of global warming / E.N. Eziukwu

Eziukwu, Emenike Nduaka January 2008 (has links)
Nigeria is presently being faced with a growing electricity demand problem following its population growth rate. The total installed capacity is far less than the current demand for electricity supply. As a way of bridging out this supply gap, the federal government is mobilizing all of its potential energy options. Coal is widely used for power generation in many countries. But today, the continued usage of coal for power generation is being challenged by the disturbing global warming phenomenon. This is due to the quantity of uncontrolled carbon dioxide emission from traditional coal-fired power plants. The aim of this dissertation is to critically analyse the future of the Nigerian coal power stations following the need to do carbon dioxide emission control necessary for ensuring a sustainable environment. Achieving this aim entails the appraisal of environmental regulation standards and cost structures of carbon dioxide (C02) emission reduction options for the coal power stations. Controlling carbon dioxide emission from existing coal power stations requires retrofit system that captures and effectively sequestrates the captured CO2. The cost and performance effect of the CO2 retrofit system on the existing power plant can be simulated with standard computer software models. In this study the lECM-cs computer modelling tool for power plants was used in determining the cost and performance impacts of applying an Amine-based C02 capture system to the Oji river power station in Nigeria. With the lECM-cs model, it was established that reducing C02 emission imposes an additional cost on the power plant which increases the unit cost of electricity generated. This additional cost index requires economic justification for its acceptance. This is due to the need to demonstrate its viability judging from the cost of electricity generated from other sources in the Nigerian economy. For the Oji river case, the station is old and requires extensive renovation. This causes a cost escalation over and above the cost associated with the CO2 sequestration system. As such, Oji coal power station does not have an economic future if C02 emission sequestration becomes obligatory. The future of coal power stations in Nigeria can be considered from two scenarios: one where the current national environmental standard is retained and another where it is revised. The revision classifies CO2 as a pollutant which makes its emission reduction imperative for coal power plants. Under the current standard, building modern large capacity pulverized coal-fired power plants with improved steam cycles should be encouraged. But with the review of the national standard, the focus should be on building new large capacity coal power stations with integrated CO2 emission control. This will ensure an environmentally friendly future for coal power stations in Nigeria. / Thesis (M.Ing. (Development and Management Engineering))--North-West University, Potchefstroom Campus, 2009.
79

Inside The Power Station : Allegory And The Dance Of Represented Ideas

Cunnington, Maree Helen January 2004 (has links)
This performance-as-research project incorporated a five-month residency inside a working power station, Swanbank, Ipswich, a provider of electricity to Australia's eastern states via the national grid. The concept 'power station' is compelling because it involves the transformation of material form (coal) to immaterial phenomena (electricity), a process analogous to making electronically-mediated art. Three linked interdisciplinary works were created out of the artist's immersion on site: Swanshift, a music-video eulogy to the closure of the station's oldest coal-fired facility, Swanbank 'A'; The Industrial Theatre, a photographic series featuring Swanbank workers; and unstatic, a live, video-mediated performance. As an enquiry into meaning within contemporary art practice, this research project used allegory as its symbolic mode of thought and formation. Through allegory, the Swanbank site was explored metaphorically to reveal a fictional, parallel world beyond the literal surface of danger, authority and rigour. In this space of excess, unreality and overflowing boundaries, meaning is multiple and celebrated. Hand-in-hand with an exploration of allegory, this exegesis also presents an insight into methodologies for industrial, site-specific, interdisciplinary practice, and arts-industry collaboration.
80

fauna flebotomínica, condições sócio- ambientais e a transmissão da Leishmaniose visceral em Uberlândia-MG, Brasil

Paula, Márcia Beatriz Cardoso de 30 June 2010 (has links)
Leishmaniasis is a infect parasitic disease complex with a zoonotic character and vetorial trasmition caused by different morfologic species similar to flagellated protozoa of the Leishmania genus. They represent a serious problem of public health with cases registered on almost all the continents. Despite the existence of drugs with effective action on the parasitics, nearly two million new cases of distints clinic form happen every year and 350 million people are under risk of contracting the disease. As the interest of the pharmaceutical industry in this problem is small because of the reduced potential of lucrative return, once the reached population has a low income, the leishmaniasis is part of the group of the neglected diseases. In addition, it is believed that the environmental transformations and the man's intense migratory process to peripheries of the cities under inadequate conditions of habitation and improvement caused changes in the transmission way of the disease, causing the expansion of the endemic areas and the existence of new focus in urban areas of municipalities of medium and big load. In Uberlândia studies demonstrated that the construction of hydroelectric power station produced ecological modifications and they interfered in the biological communities, like the prevalence of the vectors in the peridomicile area. The general objective of this work was the research around the transmission of leishmaniasis in Uberlândia - MG and had as specific objectives the study of the sandfly fauna, the environmental conditions related to the presence of the Lutzomyia longipalpis, to describe the profile seroepidemiologic of the canine population and to relate the occurrence of the visceral leishmaniase in Uberlândia with the environmental alterations. In the period of february of 2005 to december of 2007 systematized monthly collections were accomplished, using luminous traps models CDC and, in the peridomicile areas of residences closed to the woods, the trap of the type hut of Shannon was used, in 17 places to Araguaia river s margins near of Miranda's hydroelectric power station and Amador Aguiar Naves I and II. They were collected 1.695 phlebotomine sand flies specimens belonging to 16 species. The species of importance epidemic more prevalent were Lutzomyia whitmani (31%) and L. longipalpis (13,3%), reaching up to 44,3% of the total collected specimens. Inquiries canine were accomplished in animals of both sexes and the same or superior age to three months, residents in places of the study area where specimens of L. longipalpis were captured. During the study period 747 dogs were tested and no one showed acting result for the disease. Of the ecological factors analyzed in the study area, the presence of animal shelters in the peridomicile areas of the analyzed residences showed strong influence in the domiciliation of the L. longipalpis and they point for the domiciliation of L. whitmani. Our studies demonstrated although the occurrence of the first case human of human visceral leishmaniase in Uberlândia didn't proceed to the cases of canine leishmaniase. Now the leishmaniase already constitutes a problem of public health in the municipality and the epidemic study is decisive factor for the effective planning of strategies for the control of the disease. / As leishmanioses são um complexo de doenças infecto-parasitárias, de caráter zoonótico e transmissão vetorial, causadas por diferentes espécies morfologicamente semelhantes de protozoários flagelados do gênero Leishmania. Constituem um importante problema de saúde pública, com registro de casos em quase todos os continentes. Embora existam drogas com ação eficaz sobre os parasitos, aproximadamente dois milhões de novos casos de diferentes formas clínicas ocorrem a cada ano e 350 milhões de pessoas se encontram sob risco de contrair a enfermidade. Como o interesse da indústria farmacêutica nesse tema é pequeno, pelo reduzido potencial de retorno lucrativo, uma vez que a população atingida é de baixa renda, as leishmanioses fazem parte do grupo das doenças negligenciadas. Em adição, acredita-se que as transformações ambientais e o intenso processo migratório do homem para as periferias das cidades sob condições inadequadas de habitação e saneamento provocaram mudanças no padrão de transmissão da doença, acarretando a expansão das áreas endêmicas e o aparecimento de novos focos em áreas urbanas de municípios de médio e grande porte. Em Uberlândia, estudos demonstraram que a construção de usinas hidrelétricas produziram modificações ecológicas e interferiram nas comunidades biológicas, dentre estas, a prevalência dos vetores nos peridomicílios. O objetivo geral deste trabalho foi estudar a transmissão de Leishmanioses em Uberlândia MG e teve como objetivos específicos estudar a fauna flebotomínica, estudar as condições ambientais relacionadas à presença do Lutzomyia longipalpis, descrever o perfil soroepidemiológico da população canina e relacionar a ocorrência da leishmaniose visceral em Uberlândia com as alterações ambientais. No período de fevereiro de 2005 a dezembro de 2007 coletas mensais sistematizadas foram realizadas, utilizando armadilhas luminosas modelo CDC e, no peridomicílio de residências localizadas muito próximas da mata, foi utilizada a armadilha do tipo barraca de Shannon, em 17 localidades às margens do Rio Araguari, próximas às UHE de Miranda e Amador Aguiar Naves I e II. Foram coletados 1.695 espécimes de flebotomíneos pertencentes a 16 espécies. As espécies de importância epidemiológica mais prevalentes foram Lutzomyia whitmani (31%) e L. longipalpis (13,3%), perfazendo juntas 44,3% do total de espécimes coletados. Foram realizados inquéritos caninos censitários em animais de ambos os sexos e idade igual ou superior a três meses, residentes em localidades da área de estudo onde foram capturados exemplares de L. longipalpis. Durante o período de estudo foram testados 747 cães e nenhum animal apresentou resultado reagente para a doença. Dos fatores ecológicos analisados na área de estudo, a presença de abrigos de animais no peridomicílio das residências analisadas mostrou forte influência na domiciliação do L. longipalpis e apontam para a domiciliação de L. whitmani. Nossos estudos demonstraram ainda que a ocorrência do primeiro caso humano de leishmaniose visceral humana em Uberlândia não precedeu ao de casos de leishmaniose canina. Atualmente a leishmaniose já constitui um problema de saúde pública no município e, o estudo epidemiológico é fator decisivo para o planejamento efetivo de estratégias para o controle da doença. / Doutor em Geografia

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