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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.

Cost-Benefit Assessments of Distributed Power Generation Based On Micro Gas Turbine

Chen, Chien-hung 10 August 2007 (has links)
Human beings are facing instant and serious chemical fuel shortage and global warming subjects. We have being relying on the central power system, but causing low power efficiency and series environmental issues. Distributed power system can affect efficiently on the large investment on capital and land for central power system. It can backup the central power system for power management to maximize the power efficiency. It is one of the options for power system. Therefore, we expect to build up a reasonable measurer to the micro gas turbine thermal efficiency when the fat becomes power.

Late Holocene climate change and calving glacier fluctuations along the southwestern margin of the Stikine Icefield, Alaska /

Viens, Robert J. January 2001 (has links)
Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 121-129).

How bad will climate change get? factors and mechanisms of global warming /

White, Joseph F. January 1900 (has links)
Thesis (Honors)--University of South Florida, 2009. / Includes bibliographical references (p. 39-42).

Modelling climate change impacts on groundwater resources in the west Norfolk chalk aquifer

Yusoff, Ismail January 2000 (has links)
No description available.

Global changes in synoptic activity with increasing atmospheric CO2

Lim, Eun-Pa Unknown Date (has links) (PDF)
Over the last century, increases in anthropogenic greenhouse gases and global temperature in the atmosphere has drawn our attention to changes in extra tropical cyclones which influence daily weather patterns in the mid and high latitudes and redistribute energy, momentum and moisture across the globe. This study is aimed at examining changes in extra tropical cyclones: observed over the past two decades using the NCEP-DOE reanalysis II data (NCEP2); and simulated in the CSIRO Mark2 atmosphere-ocean coupled general circulation model (GCM) with increasingCO2. Furthermore, we attempt to explore the physical mechanisms driving such changes by modelling idealised experiments with the Melbourne University atmospheric GCM. The Melbourne University cyclone finding and tracking scheme is utilised to detect and track cyclones observed in NCEP2 and simulated in the two models. / The study demonstrates significant changes in Southern Hemisphere (SH) cyclone features from 1979-2000. SH cyclones have decreased in their number at the surface but increased at the 500 hPa level. On the other hand, SH cyclone physical features such as intensity, radius and depth have significantly increased over the two decades at the mean sea level and 500 hPa level. Moreover, cyclones became vertically better organized in both hemispheres, and particularly in the SH. The changes in the characteristics of Northern Hemisphere (NH) cyclones were statistically less significant than their SH counterparts in the period of 1979-2000. / Results from the coupled climate model simulation with enhanced CO2 suggest general reductions in cyclone frequency and intensity throughout the troposphere between the surface and500 hPa level but increases in cyclone radius and organization of vertical structure. These changes are persistent throughout the entire transient run with increasing CO2 and during a 100 year stabilisation period. It is found in the CSIRO simulation with enhanced CO2 that the geographical changes of cyclone features are similar in both hemispheres and between the surface and 500 hPa level. Furthermore, we conclude that some observed changes in extra tropical cyclone features seem to follow the patterns of simulated changes with increasing CO2 from 1xCO2 to 2xCO2 particularly in the SH. / Modelling latitudinal temperature gradient at different levels of the troposphere has revealed that the warming over the tropics at the upper troposphere causes cyclone frequency and depth to increase in the high latitudes but decrease in the mid latitudes. By contrast, the warming over the high latitudes at the lower troposphere results in decreases in the cyclone features in the high latitudes but increases in them in the mid latitudes. Therefore, the warming over the tropics seems to play an important role in the changes in SH summer cyclone frequency and depth appearing in the simulation with enhanced CO2, whereas the warming over both tropics and high latitudes affects the changes in SH winter cyclone features. In the NH, the change in latitudinal temperature gradient seems less influential in the changes of cyclone features than it does in the SH.

The faithful skeptics conservative Christian religious beliefs and perceptions of climate change /

Carr, Wylie Allen. January 2010 (has links)
Thesis (MS)--University of Montana, 2010. / Contents viewed on July 18, 2010. Title from author supplied metadata. Includes bibliographical references.

Corporate newspapers, global warming, and the editorial vigor hypothesis

Kim, Taehyun, January 2007 (has links) (PDF)
Thesis (Ph. D.)--Washington State University, August 2007. / Includes bibliographical references (p. 83-95).

Avaliação de cenarios no contexto do aquecimento global : estudo de caso da bacia rural do Monjolinho, Piracicaba-SP / Assessment in the global warning context : case study Monjolinho rural basin, Piracicaba, São Paulo, Brazil

Paiva Sobrinho, Ranulfo 1 14 August 2018 (has links)
Orientadores: Antonio Carlos Zuffo, Rozely Ferreira dos Santos / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-14T09:41:38Z (GMT). No. of bitstreams: 1 PaivaSobrinho_Ranulfo1_M.pdf: 1791729 bytes, checksum: 787620cb6a44e874ece86d8e0332fbe2 (MD5) Previous issue date: 2007 / Resumo: Um dos efeitos do aquecimento global é o aumento da ocorrência de precipitações extremas, as quais podem gerar diversos impactos negativos às áreas rurais, como enchentes e erosão. Assim, nas áreas de produção agrícola, como as da cana-de-açúcar, é importante que os usos da terra estejam distribuídos ao longo da bacia de modo a minimizarem os processos de escoamento superficial e de erosão perante tais eventos extremos. Além disso, que tais usos possam auxiliar no seqüestro de carbono, reduzindo os gases de efeito estufa. Diante desses critérios, este trabalho foi desenvolvido em uma área produtora de cana-de-açúcar, com problemas ambientais, e partindo-se do cenário atual, gerou-se novos cenários que atendam os requisitos legais ambientais, possam gerar lucro e ocupação de mão-de-obra, além de minimizar o escoamento superficial, a erosão, e aumentar o seqüestro de carbono. Foram utilizadas modelagem espacial dinâmica, ecologia da paisagem, valoração econômica, para quantificar cada cenário perante os critérios selecionados. Após isso, atribuindo-se funções de valores a cada critério, utilizou-se o método multicriterial, Compromise Programming (CP) para selecionar os melhores cenários. A utilização dos vários métodos mostrou-se adequada perante os propósitos do trabalho. / Abstract: One of the global warming effects is the increase of extreme rainfalls, which can cause many negative impacts to rural areas, such as floods and erosion. So, it is important that an equitable land use is distributed along river basins, especially in the ones where there are agricultural fields, since it can help to minimize runoff and soil erosion caused by extreme events. Furthermore, culture or cultures that help in carbon absorption presented in the atmosphere are able to reduce gases responsible for the green house effect. In this context, this work is developed in a sugar cane production area, which presents environmental problems, and aims to create scenarios that respects legal issues, generates profits, helps land occupation, settles labor force, minimizes runoff and soil erosion and increases carbon absorption. The reference scenario is the one found today, just as it is, and the produced ones are made with the assistance of a GIS tool - IDRISI. GIS also helps in the spatial dynamic modeling, landscape ecology characterization and value ration of economical issues, in order to quantify and compare each produced scenario, according to the chosen criteria. The Compromise Programming (CP) multi-criteria method is chosen to rank these scenarios and proved itself to be an effective tool. It is produced 14 different scenarios, taking into account 11 criteria (3 economical, 3 social, 3 environmental and 2 technical), in 2 different weights scenarios; one is to assess the 14 alternatives and the other is to verify the economical sustainability of the best alternatives. So, the economical criteria have theirs weights tripled. The three best alternatives pointed out by the CP remained the same despite the weights scenario, which proves their sustainability. / Mestrado / Recursos Hidricos, Energeticos e Ambientais / Mestre em Engenharia Civil

Comparative analysis of biohydrogen producing bacterial consortia in three thermophilic anaerobic fluidised bed bioreactors

Sebola, Keneilwe Mmule January 2012 (has links)
A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, in partial fulfilment of the requirements for the degree of Master of Science in Medicine (Pharmaceutical Affairs). Johannesburg 2012 / Global warming has stimulated research into alternative energy carries and fuels. Hydrogen is one of these alternative fuels that are recognized as a promising future energy source. Historically, it is produced by water electrolysis and the gasification of coal. Hydrogen is a natural though transient by-product of several microbial driven biochemical reactions, including anaerobic digestion and fermentation. Microorganisms degrade complex molecules to produce butyrate and alcohols with CO2 and hydrogen as the only by- products. Hydrogen produced by microorganisms is known as biohydrogen. This study aimed to identify biohydrogen- producing bacteria in three Anaerobic Fluidised Bed Bioreactors (AFBRs), which are capable of producing hydrogen under anaerobic and thermophilic conditions, by using PCR-DGGE analysis of the 16 S rDNA genes. Sewage sludge from anaerobic digester and cow- dung were used as inoculum to isolate potential H2- producing organisms. The operational conditions were manipulated to removing mesophilic bacteria and non- spore forming bacteria by gradually increasing the temperature to thermophilic conditions and the pH maintained at acid conditions to allow acidotolerant bacteria to survive. The bioreactors were operated for a period of forty days for each research cycle. Bioreactor One was operated at 55°C for eight days and then the temperature kept at a constant 65°C for the remainder of the research cycle. Bioreactor Two was operated for 8 days at each temperature ranging from 45°C - 65°C, with increments of 5 °C. Bioreactor Three was operated at each temperature for ten days ranging from 55- 70°C, also with increments of 5°C. Samples for microbial community identification were taken at 55°C and 65°C. The bacterial morphologies and structural properties were evaluated by examining the hydrogen- producing granules, isolated at 65°C, using scanning electron microscopy. Species of the families Bacillus, Enterobacteria, Actinomyces, Clostridium and Veillonella were identified. Clostridium thermopalmarium, Bacillus coagulans and Bacillus thermoamylovorans were the culturable species at the desired operational temperature of 65°C. C. thermopalmarium and B. coagulans are major H2 producers with theoretical values of 4mol H2/ g glucose and 3mol H2/ mol sugar, respectively. Sewage sludge is the best source of biohydrogen producing bacteria in comparison to cow dung as an inoculum in AFBRs. Bioreactor 1 with a constant operational temperature of 65°C and at a HRT of 6.5 allowed for the desired Clostridium sp. to be the predominant H2 producer.

The application of stochastic modelling techniques to global climate change

Parkinson, Stuart D. January 1994 (has links)
No description available.

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