• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 34
  • 7
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 47
  • 47
  • 47
  • 16
  • 16
  • 15
  • 15
  • 12
  • 11
  • 10
  • 9
  • 9
  • 7
  • 7
  • 6
  • 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.
31

National policy choices for an international problem case studies in greenhouse policy /

Kelly, Geoffrey. January 2008 (has links)
Thesis (Ph.D.)--University of Wollongong, 2008. / Typescript. Includes bibliographical references: leaf 317-346.
32

An apparatus to investigate photon induced gaseous reactions using Fourier transform infrared spectroscopy /

Manning, Gregory A. January 2000 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 132-137). Also available on the Internet.
33

Mudanças de uso da terra e estimativas de emissões antrópicas de CO2 em bacia hidrográfica /

Sousa, Jocy Ana Paixão de. January 2018 (has links)
Orientador: Roberto Wagner Lourenço / Resumo: As interferências antrópicas sobre natureza sempre provocaram impactos ambientais. Porém, entre os mais significativos encontram-se as mudanças de uso da terra, nos quais contribuem com as emissões dos gases do efeito estufa. Entre esses principais gases destacam-se o dióxido de carbono, CO2. O estudo apresentou como objetivo estimar as emissões do dióxido de carbono devido as mudanças de uso da terra para a análise do fluxo de carbono em bacia hidrográfica. A área de estudo localiza-se na Bacia Hidrográfica do Rio Una, Ibiúna, São Paulo. Para atingir os objetivos foram realizados o mapeamento de uso do solo e cobertura vegetal, mapeamento pedológico, análise da textura do solo, mapeamento da vegetação pretérita, estoque de carbono sob associação solo-vegetação, matriz de transição e os cálculos das emissões líquidas de CO2. Constatou-se que em relação ao mapeamento do uso do solo e cobertura vegetal, o maior quantitativo foi de floresta e estas predominam no sul da bacia. Ao longo de nove anos houve uma redução de florestas, campo e área alagada e um aumento da área de agricultura, área urbana, pastagem e reflorestamento. Foram encontrados solos do tipo Argissolos e Latossolos, além das texturas argilosa, franco-argilo-arenosa, argilo-arenosa e franco-argilosa. Para a vegetação pretérita constatou-se floresta ombrófila densa montana, floresta estacional decidual e semidecidual. Em relação ao conteúdo de carbono no solo sob a associação solo-vegetação foram definidos valores ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Anthropogenic interference with nature has always had environmental impacts. However, among the most significant are land use changes, in which they contribute to the emissions of effect gases, especially carbon dioxide, CO2. The objective of the study was to estimate carbon dioxide emissions due to the change in land use for an analysis of the carbon flux in the watershed. The study area is located in the Una Watershed, Ibiúna, São Paulo. To achieve the objectives, the mapping of land use and vegetation cover, pedological mapping, soil texture analysis, mapping of past vegetation, carbon stock under soil-vegetation association, transition matrix, and calculations of net CO2 emissions. It was verified that in relation to the mapping of the land use and vegetal cover, the biggest quantitative one was of forest and these predominate in the south of the basin. During nine years there was a reduction of forests, field and flooded area and an increase of the area of agriculture, urban área, pasture and reforestation. Soils of the type Argisols and Latosols were found, in addition to clay, clay-loam-sandy, clay-sandy and loam-loamy textures. For the past vegetation it was verified dense montane forest, deciduous and semidecidual forest. Regarding the non-singlet carbon content in a soil-vegetation association to define values ranging from 2.59 to 6.33 Kgc / m2. In the transitional matrices for the periods 2007-2010, 2010-2013 and 2013-2016, it was observed that the forest converted... (Complete abstract click electronic access below) / Mestre
34

Development and optimization of selective leaching processes for the extraction of calcium from steel slag in view of sequestering carbon dioxide

Kotoane, Alice Mpho 05 1900 (has links)
M. Tech. (Department of Chemistry, Faculty of Applied and Computer Sciences), Vaal University of Technology / Several technologies are currently being developed to mitigate the greenhouse gas CO2. One of these promising processes is industrial mineral carbonation whereby alkaline industrial wastes are taken as raw material. The process is a multi-step process which involves the extraction of calcium from industrial alkaline wastes and the subsequent reaction of extracted calcium rich supernatant with CO2 at elevated pH to form stable carbonates. Steelmaking slags were selected from four different plants in SA and used for this investigation owing this to their high calcium content. The potentially-suitable four slags were selected on the basis of their Ca content and high chemical reactivity. The objective of this investigation was to develop a common leach process for all four steel slags to achieve a complete Ca extraction from slags. A Ca rich solution was carbonated to achieve a stable carbonate that can be used. Experiments were carried out using ammonium reagents and a hydroxide reagent to investigate their suitability for the rapid, selective extraction of calcium. Calcium was leached under different experimental conditions including varying leachant concentrations, temperatures and solid to liquid ratios. The slags exhibited contrasting reactive properties to different leachants, which can essentially be explained in terms of differences in mineralogical composition, hence mineral solubility characteristics. Leaching with 2M NH4NO3 aqueous solution at room temperature extraction efficiency increased with increasing concentration. The extent of extraction was different for the four slags. WMO5 showed a complete dissolution of Ca within 20 min of experiment. This difference is due to their different Ca-containing minerals. Same is observed with aqueous NH4CL but WMO5 did not reach a complete dissolution as with NH4NO3. Aqueous NaOH made it impossible for Ca extraction due to its high pH and upon slag addition it was more elevated. Increasing solid to liquid ratio had an influence in percentage slag loss. The pH of leach solution was elevated to 9 making it difficult to extract Ca. Under controlled conditions (pH kept under 1) optimal slag dissolution was achieved with traces of larnite and large amount of brownmillerite. The generated Ca-rich leachate was carbonated in a 600 ml reactor vessel with liquid CO2. A stable carbonate aggregate was produced. / Council for Geoscience Vaal University of Technology
35

Response of Pinus banksiana (Lamb.) families to a global change environment

Cantin, Danielle, 1967- January 1994 (has links)
We examined how fast- and slow-growing families (based on height at 10 years) of Pinus banksiana Lamb. are affected by a climate altered by CO$ sb2$ during their first growing season. Our primary objective was to evaluate the possibility that genotypes performing best under present conditions may not necessarily do best under projected warmer climate. Seedlings were grown for six months in two climatic environments (350 $ mu$L/L CO$ sb2$ x present temperatures and 700 $ mu$L/L CO$ sb2$ x 4$ sp circ$C warmer temperatures) and with 100 ppm and 5 ppm nitrogen. / The CO$ sb2$T$ sp circ$ environment had a significant effect on most biomass components of seedlings and water-use efficiency but not on height and other growth variables. The nitrogen fertilization was generally the most significant effect of the treatments for most growth variables. / All the families responded in a similar way to variations in the growing environments except for WUE. Family differences were more important for measurements of height and growth variables than for biomass components. The architecture of seedlings was also highly variable between families. Norm of reaction graphs were built for several growth variables to outline which families were overall most successful in an enriched CO$ sb2$T$ sp circ$ environment. Of the 15 families studied, four of them were classified as most successful in a projected high CO$ sb2$T$ sp circ$ climate.
36

Análise da matriz energética brasileira sob a visão sistêmica: programas energéticos governamentais e a redução de gases de efeito estufa

Lückemeyer, Alfonso Celso Arruda Bianchini 27 April 2010 (has links)
Essa dissertação propôs como tema de estudo um panorama das energias renováveis e menos poluentes no Brasil, com enfoque para as mudanças climáticas globais, mais especificamente a emissão de gases de efeito estufa. O objetivo da pesquisa foi analisar a matriz energética brasileira no que se refere à relação entre a oferta de energia renovável, regulamentada pelas políticas e programas governamentais e a emissão de gases de efeito estufa. Esta análise foi realizada por meio de uma contextualização da matriz energética brasileira no panorama mundial, da relação entre os usos de energias com as mudanças climáticas globais e do estudo dos programas energéticos brasileiros e sua contribuição para minimizar a emissão de poluentes atmosféricos. Para o desenvolvimento deste estudo foi realizado um levantamento histórico, por meio de revisão bibliográfica, do uso da energia e de programas energéticos governamentais, da oferta de energia e emissões de CO2 e cenários para o ano de 2030, dos acordos internacionais e mecanismos para a mitigação de mudanças climáticas, dos setores da sociedade brasileira que mais consomem energia e quais as fontes utilizadas por esses setores, das tecnologias de energias renováveis disponíveis e os danos climáticos por elas causados nos processos energéticos. A ótica epistemológica sistêmica fundamentou essa dissertação, cujo método mostrou-se adequado ao encaminhamento da questão energética para o jogo de harmonização entre recursos naturais, consumo e danos climáticos, com base na visão de uma ecossocioeconomia. Como principais resultados verificou-se que é possível aumentar a participação de energias renováveis e menos poluentes tais como eólica, solar, PCH e biomassa na matriz energética brasileira e promover a eficiência energética de forma a aumentar a oferta de energia, diminuindo a necessidade da utilização de recursos energéticos naturais e os impactos ambientais decorrentes. Constatou-se que as políticas e programas energéticos governamentais contribuem para o incentivo do uso de energias renováveis e para a melhoria dos índices de poluentes atmosféricos. Concluiu-se que para mitigar a emissão de gases de efeito estufa a partir dos processos energéticos e simultaneamente garantir a continuidade do desenvolvimento econômico faz-se necessário um conjunto de medidas que inclua: a substituição gradativa de fontes fósseis na matriz energética por fontes renováveis, associada à eficiência energética e a programas governamentais integrados e viáveis em termos políticos, econômicos, tecnológicos e sócio-ambientais. Observou-se que há um jogo de forças envolvendo energia entre as necessidades sócio-ambientais e de desenvolvimento econômico e, portanto, no momento presente e para um futuro próximo não há como descartar a total utilização de energias não renováveis (termelétricas a combustíveis fósseis e a energia nuclear e combustíveis fósseis para o setor de transportes), tendo em vista a necessidade de se atender à questão da segurança energética. / This thesis proposed as subject of study an overview of renewable and less pollutant energy in Brazil, focusing on global climate change, specifically the emission of greenhouse gases. The objective of the research is to analyze the Brazilian energy matrix with respect to the relation between the supply of renewable energy, regulated by governmental policies and programs, and the issue of greenhouse gases. This analysis is made through a contextualization of the Brazilian energy matrix in the world scene, of the relation between the uses of energy and global climate change, and of the analysis of energy programs in Brazil and their contribution to minimize the emission of air pollutants. For this study, a historical survey was conducted, by means of literature review, on the use of energy and governmental energy programs, energy supply, CO2 emissions and scenarios for the year 2030, international agreements and mechanisms for climate change mitigation, sectors of Brazilian society that consume more energy and what are the sources they use, renewable energy technologies available and the climate damage caused by them in energy processes. The systemic epistemological view has based this thesis, since this method was suitable for the managing of the energy issue for the game of harmonization among natural resources, consumption and climate damage, based on the view of an ecossocioeconomia. The main results showed that it is possible to increase the share of less pollutant and renewable energy such as wind, solar, small hydropower plants and biomass in the Brazilian energy matrix and promote energy efficiency in order to increase the supply of energy, reducing the need of using natural energy resources and the consequent environmental impact. It was noted that governmental energy policies and programs contribute to encourage the use of renewable energy and to improve levels of air pollutants. It was concluded that, in order to reduce the emission of greenhouse gases from energy processes while guaranteeing the continuity of economic development, a set of measures is necessary, including: gradual replacement of fossil fuels in energy matrix by renewable sources, in association with energy efficiency, and integrated and viable governmental programs in political, economic, technological and socio-environmental terms. It was observed that there is an interplay of forces involving energy between socio-environmental and economic development and, therefore, at present and near future there is no way to rule out the use of totally non-renewable energy (thermoelectric power plants run by fossil fuels and nuclear energy, and fossil fuels for the transportation sector), considering the need to address the issue of energy safety. / 5000-11-25
37

Análise da matriz energética brasileira sob a visão sistêmica: programas energéticos governamentais e a redução de gases de efeito estufa

Lückemeyer, Alfonso Celso Arruda Bianchini 27 April 2010 (has links)
Essa dissertação propôs como tema de estudo um panorama das energias renováveis e menos poluentes no Brasil, com enfoque para as mudanças climáticas globais, mais especificamente a emissão de gases de efeito estufa. O objetivo da pesquisa foi analisar a matriz energética brasileira no que se refere à relação entre a oferta de energia renovável, regulamentada pelas políticas e programas governamentais e a emissão de gases de efeito estufa. Esta análise foi realizada por meio de uma contextualização da matriz energética brasileira no panorama mundial, da relação entre os usos de energias com as mudanças climáticas globais e do estudo dos programas energéticos brasileiros e sua contribuição para minimizar a emissão de poluentes atmosféricos. Para o desenvolvimento deste estudo foi realizado um levantamento histórico, por meio de revisão bibliográfica, do uso da energia e de programas energéticos governamentais, da oferta de energia e emissões de CO2 e cenários para o ano de 2030, dos acordos internacionais e mecanismos para a mitigação de mudanças climáticas, dos setores da sociedade brasileira que mais consomem energia e quais as fontes utilizadas por esses setores, das tecnologias de energias renováveis disponíveis e os danos climáticos por elas causados nos processos energéticos. A ótica epistemológica sistêmica fundamentou essa dissertação, cujo método mostrou-se adequado ao encaminhamento da questão energética para o jogo de harmonização entre recursos naturais, consumo e danos climáticos, com base na visão de uma ecossocioeconomia. Como principais resultados verificou-se que é possível aumentar a participação de energias renováveis e menos poluentes tais como eólica, solar, PCH e biomassa na matriz energética brasileira e promover a eficiência energética de forma a aumentar a oferta de energia, diminuindo a necessidade da utilização de recursos energéticos naturais e os impactos ambientais decorrentes. Constatou-se que as políticas e programas energéticos governamentais contribuem para o incentivo do uso de energias renováveis e para a melhoria dos índices de poluentes atmosféricos. Concluiu-se que para mitigar a emissão de gases de efeito estufa a partir dos processos energéticos e simultaneamente garantir a continuidade do desenvolvimento econômico faz-se necessário um conjunto de medidas que inclua: a substituição gradativa de fontes fósseis na matriz energética por fontes renováveis, associada à eficiência energética e a programas governamentais integrados e viáveis em termos políticos, econômicos, tecnológicos e sócio-ambientais. Observou-se que há um jogo de forças envolvendo energia entre as necessidades sócio-ambientais e de desenvolvimento econômico e, portanto, no momento presente e para um futuro próximo não há como descartar a total utilização de energias não renováveis (termelétricas a combustíveis fósseis e a energia nuclear e combustíveis fósseis para o setor de transportes), tendo em vista a necessidade de se atender à questão da segurança energética. / This thesis proposed as subject of study an overview of renewable and less pollutant energy in Brazil, focusing on global climate change, specifically the emission of greenhouse gases. The objective of the research is to analyze the Brazilian energy matrix with respect to the relation between the supply of renewable energy, regulated by governmental policies and programs, and the issue of greenhouse gases. This analysis is made through a contextualization of the Brazilian energy matrix in the world scene, of the relation between the uses of energy and global climate change, and of the analysis of energy programs in Brazil and their contribution to minimize the emission of air pollutants. For this study, a historical survey was conducted, by means of literature review, on the use of energy and governmental energy programs, energy supply, CO2 emissions and scenarios for the year 2030, international agreements and mechanisms for climate change mitigation, sectors of Brazilian society that consume more energy and what are the sources they use, renewable energy technologies available and the climate damage caused by them in energy processes. The systemic epistemological view has based this thesis, since this method was suitable for the managing of the energy issue for the game of harmonization among natural resources, consumption and climate damage, based on the view of an ecossocioeconomia. The main results showed that it is possible to increase the share of less pollutant and renewable energy such as wind, solar, small hydropower plants and biomass in the Brazilian energy matrix and promote energy efficiency in order to increase the supply of energy, reducing the need of using natural energy resources and the consequent environmental impact. It was noted that governmental energy policies and programs contribute to encourage the use of renewable energy and to improve levels of air pollutants. It was concluded that, in order to reduce the emission of greenhouse gases from energy processes while guaranteeing the continuity of economic development, a set of measures is necessary, including: gradual replacement of fossil fuels in energy matrix by renewable sources, in association with energy efficiency, and integrated and viable governmental programs in political, economic, technological and socio-environmental terms. It was observed that there is an interplay of forces involving energy between socio-environmental and economic development and, therefore, at present and near future there is no way to rule out the use of totally non-renewable energy (thermoelectric power plants run by fossil fuels and nuclear energy, and fossil fuels for the transportation sector), considering the need to address the issue of energy safety. / 5000-11-25
38

Response of Pinus banksiana (Lamb.) families to a global change environment

Cantin, Danielle, 1967- January 1994 (has links)
No description available.
39

Spectroscopic study of channel spectra phenomena in the synchrotron-based FTIR spectrometer at the Canadian Light Source

Ibrahim, Amr, University of Lethbridge. Faculty of Arts and Science January 2010 (has links)
Recently, the high radiance of synchrotron sources was used to enhance FTIR spectrometer performance. However, excessive channel spectra when synchrotron sources are used degrade the quality of retrieved spectral parameters. In the research reported in this thesis, seven different techniques for handling channel spectra were investigated. These techniques were used to reduce channel spectra for a test group of seven samples of CO2 mixed with air recorded using the synchrotron source at the Canadian Light Source. The increases in signal to noise ratio (SNR) of spectra handled with each technique were calculated. SNR results showed that transmission spectra, produced using synthetic background spectra with simulated channel spectra, achieved the highest SNR improvement. However, when the spectra groups were fitted using nonlinear least square fit algorithm, the technique using channel spectra fitting produced the smallest fitting residual. Moreover, the retrieved intensities and air broadening coefficients of 21 spectral lines showed that the spectral fitting technique produced the most accurate values as compared to the HITRAN 2008 database. Although the spectral fitting technique was accurate in retrieving spectral line parameters, applying the technique at wider spectral ranges was less accurate. A modification to the channel spectra fitting technique by performing iterations of channel fitting was introduced to process wider spectral ranges. Carbon dioxide laser band I centred at 961 wavenumber was analyzed using 24 spectra recorded under different experimental conditions. The intensity and air-and self-broadening coefficients were retrieved for 48 spectral lines with average deviations from HITRAN database values of 2.11%, 1.25% and 4.14%, respectively, using the Voigt profile. These average deviations lie within the uncertainty limits listed by the database. The deviation between our results and other results reported in the literature were also examined and it is found to be also within the range of HITRAN uncertainties. The effect of errors in fitting channel spectra parameters was examined and found to be mitigated by the inclusion of channel-free spectra in the multispectral fit. / xiv, 134 leaves : ill. ; 29 cm
40

Agent behavior in peer-to-peer shared ride systems /

Wu, Yunhui. January 2007 (has links)
Thesis (M.Geom.M.)--University of Melbourne, Dept. of Geomatics, 2007. / Typescript. Includes bibliographical references (leaves 100-104).

Page generated in 0.1108 seconds