No description available.

The present project has made a comprehensive assessment of the effect of Nb doping on various charge-transfer related properties of TiO2. Of particular focus, the electrical properties of Nb-doped TiO2 (0.65 at %) have been investigated using the simultaneous measurement of electrical conductivity and thermoelectric power. This investigation was undertaken at elevated temperatures (1073 K -- 1298 K) in equilibrium with a gas phase of controlled oxygen activity (10-10 Pa < p(O2) < 75 kPa). In addition, the effect of segregation on the surface versus bulk composition of Nb-doped TiO2 was also investigated at a function of temperature and oxygen activity. Specifically, the following determinations were undertaken: The effect of oxygen activity, p(O2) and temperature on both electrical conductivity and thermoelectric power The effect of Nb on the defect disorder and related electrical properties of TiO2 The determination of equilibration kinetics and the associated chemical diffusion data for Nb-doped TiO2 The determination of Nb bulk diffusion in TiO2 The effect of p(O2), temperature and dopant content on Nb segregation and the related surface composition of Nb-doped TiO2 The obtained electrical properties enable the determination of a defect disorder model for Nb-doped TiO2, which may be considered within the following p(O2) regimes: Strongly Reduced Regime. In this regime, the predominant ionic defect was anticipated to be oxygen vacancies compensated electronically by electrons. While the transition to this regime (from higher p(O2)) was clearly observed, the predominant defect disorder existing beyond this transition was not confirmed due to an inability to obtain sufficiently low oxygen activity. Metallic-type conductivity behaviour was observed within this transition region. Reduced Regime I. In this regime, the predominate defect disorder defined by the electronic compensation of incorporated Nb ions by electrons was clearly observed. Reduced Regime II. In this regime, the predominate defect disorder defined by the ionic compensation of incorporated Nb ions by quadruply-charged titanium vacancies, was clearly observed. The present project included the determination of diffusion data which included: Temperature dependence of 93Nb tracer diffusion in single crystal TiO2 over the temperature range 1073 K -- 1573 K Chemical diffusion coefficient over the temperature range 1073 K -- 1298 K and oxygen activity range, 10-10 Pa < p(O2) < 75 kPa These pioneering studies are significant as they enable the prediction of the processing conditions required to reliably 1) incorporate Nb into the TiO2 lattice, and 2) achieve equilibrium with the gas phase. Finally, the present project included investigations on the effect of Nb segregation on the surface composition of Nb-doped TiO2, with the following outcomes: Due to segregation, the surface can be significantly enriched in Nb compared to the bulk The extent of enrichment increases as the bulk Nb content or the oxygen activity is decreased Following enrichment, the surface Nb concentration could be sufficiently high to assume a unique surface phase The outcomes of the present project are significant as they can enable the processing of TiO2 with enhanced charge transport and controlled surface properties.

East Timor is rebuilding its stock of infrastructure after decades of underdevelopment and a wave of violent destruction in 1999. As part of this process the Government of East Timor aims to improve access to electricity from less than five percent of the population today to eighty percent by 2020. An important strategy to meeting this aim will be the use of solar home systems (SHS) in remote rural locations. To develop its policy for the deployment of SHS, the Government of East Timor must decide what size of SHS is optimal. This research investigates whether there is a relationship between SHS size and development. / The research adapts an evaluation approach developed by World Bank/UNDP Energy Sector Management Assistance Program. This approach uses a combination of participatory and quantitative tools tailored to the East Timorese context through consultations with rural households about electrification and their use of SHS. Three SHS projects in East Timor were selected for evaluation, each of which had adopted a different sized SHS for their program. The smallest systems installed were 10 Wp single-lamp systems. The largest system was rated at 80 Wp and was supplied with four or six lamps. The third type of system was 40 Wp and provided three lamps / To assess the development impact of these different sizes of SHS, a set of Participatory Evaluation exercises were conducted with seventy-seven small groups of SHS users in twenty four rural communities. These exercises were supplemented with a Socio-economic Household Survey of 195 SHS users. The combined results of these evaluation processes enabled the three sizes of SHS to be compared for two types of benefits—assistance with carrying out important household tasks (i.e. ‘lighting-derived’ benefits) and attributes of SHS which were advantageous in comparison to use of non-electric lighting sources (i.e. ‘intrinsic’ benefits). Analysis of the research results showed that the small 10 Wp SHS provided much of the development impact of the larger systems. For lighting-derived benefits, there was little difference between the development impact of small and large systems. The larger systems provided greater benefit for domestic tasks undertaken in kitchen buildings, since the small and medium sized SHS did not provide lighting in these areas. For intrinsic benefits related to health and convenience, the small systems provided much the same benefits as larger systems. For financial benefits—considered by East Timorese SHS users to be the most important of the intrinsic benefits—smaller systems were found to offer slightly positive benefits due to their lower operating costs. Larger systems, however, were found to have a negative overall financial impact. / The research suggests three significant implications for the design of SHS programs in East Timor and comparable situations elsewhere: programs should focus on providing smaller systems rather than larger ones; systems should be designed to provide a light in the kitchen wherever possible to maximise the overall development impact; and SHS operating costs should be carefully matched to the incomes of rural householders to ensure that operation of the systems can be sustained by user households.

East Timor is rebuilding its stock of infrastructure after decades of underdevelopment and a wave of violent destruction in 1999. As part of this process the Government of East Timor aims to improve access to electricity from less than five percent of the population today to eighty percent by 2020. An important strategy to meeting this aim will be the use of solar home systems (SHS) in remote rural locations. To develop its policy for the deployment of SHS, the Government of East Timor must decide what size of SHS is optimal. This research investigates whether there is a relationship between SHS size and development. / The research adapts an evaluation approach developed by World Bank/UNDP Energy Sector Management Assistance Program. This approach uses a combination of participatory and quantitative tools tailored to the East Timorese context through consultations with rural households about electrification and their use of SHS. Three SHS projects in East Timor were selected for evaluation, each of which had adopted a different sized SHS for their program. The smallest systems installed were 10 Wp single-lamp systems. The largest system was rated at 80 Wp and was supplied with four or six lamps. The third type of system was 40 Wp and provided three lamps / To assess the development impact of these different sizes of SHS, a set of Participatory Evaluation exercises were conducted with seventy-seven small groups of SHS users in twenty four rural communities. These exercises were supplemented with a Socio-economic Household Survey of 195 SHS users. The combined results of these evaluation processes enabled the three sizes of SHS to be compared for two types of benefits—assistance with carrying out important household tasks (i.e. ‘lighting-derived’ benefits) and attributes of SHS which were advantageous in comparison to use of non-electric lighting sources (i.e. ‘intrinsic’ benefits). Analysis of the research results showed that the small 10 Wp SHS provided much of the development impact of the larger systems. For lighting-derived benefits, there was little difference between the development impact of small and large systems. The larger systems provided greater benefit for domestic tasks undertaken in kitchen buildings, since the small and medium sized SHS did not provide lighting in these areas. For intrinsic benefits related to health and convenience, the small systems provided much the same benefits as larger systems. For financial benefits—considered by East Timorese SHS users to be the most important of the intrinsic benefits—smaller systems were found to offer slightly positive benefits due to their lower operating costs. Larger systems, however, were found to have a negative overall financial impact. / The research suggests three significant implications for the design of SHS programs in East Timor and comparable situations elsewhere: programs should focus on providing smaller systems rather than larger ones; systems should be designed to provide a light in the kitchen wherever possible to maximise the overall development impact; and SHS operating costs should be carefully matched to the incomes of rural householders to ensure that operation of the systems can be sustained by user households.

Renewable energy has become the world's fastest growing energy source as a direct result of increasing concerns about the environmental damage that is being caused by fossil fuel and nuclear energy use. With the exception of large-scale hydro, however, very little of Australia's electricity is supplied from renewable energy. Due to our lack of experience with the use of most renewable energy technologies and the associated lack of knowledge regarding their true potential, doubts remain as to how much electricity could be generated or displaced by renewable energy. Although renewable energy industries in Australia have recently begun to experience strong growth, this growth could be curtailed if there is a lack of faith in the potential for renewable energy. The aim of this study is to further our understanding of the potential for renewable energy to contribute to electricity supply in Australia. This aim is achieved through the development and demonstration of methodologies for estimating potential electricity production from key renewable energy resources. The study demonstrates how methodologies for assessing the potential contribution of key renewable energy resources to electricity supply in Australia can be developed utilising a spatial assessment of important resource variables within the context of plausible utilisation of renewable energy resources. A literature review provides the basis for an assessment of the current state of knowledge regarding the use of renewable energy for electricity supply in Australia. The range of different renewable energy technologies is canvassed, brief descriptions of the technologies are presented and an appraisal is made of their commercial development status. The extent to which different renewable energy technologies have been utilised for electricity supply in Australia and prospects for near-future developments are described. Scenario analysis is used to provide insights into future development paths for renewable energy. This assists in the identification of key renewable energy technologies that will be examined in more detail and it helps in the setting of parameters for assessments of these technologies. Three scenarios are presented and these provide a framework for an analysis of possible contributions by renewable energy to electricity supply in Australia. Of those technologies that could potentially make significant contributions to electricity supply in the near term, utility scale wind energy, domestic rooftop photovoltaics (rooftop BIPV) and domestic solar hot water (SHW) stand out as being key technologies where further research in relation to resource assessment would be beneficial. The dispersed nature of the resource bases utilised by these technologies has made it difficult to assess how much electricity they could generate or displace. Conventional methods of assessing electricity generation or displacement, based upon project or site-specific analyses, have not proven amenable to analyses of the total amount of electricity that could be generated or displaced by these technologies throughout Australia. Therefore, alternative methods for assessing the potential of these technologies are needed. New models for analysing wind, BIPV and SHW performance are developed in this study. These models demonstrate the application of Geographical Information Systems (GIS) for wind, BIPV and SHW resource mapping. Wind energy maps for Australia are created showing actual wind speeds suitable for use at elevations appropriate for wind turbines. These maps represent significant advances over traditional wind atlases used in other nations due to their presentation of estimated actual wind speeds, rather than isovent lines for idealised wind speed gradients. The use of GIS for analysing BIPV and SHW resources also represents a significant departure from traditional modelling processes and demonstrates a means of overcoming important limitations of existing BIPV and SHW evaluation tools. The wind, BIPV and SHW resource mapping processes that have been developed and applied in this study show how broad-area assessments of electricity supply or displacement can be produced for technologies where spatial variations in key performance attributes constrain the use of traditional modelling processes.

Thesis (M.S.)--University of Texas at El Paso, 2007. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.

Thesis (Ph.D.)-- University of Gothenburg, 2008. / "PV-ESCO Project"--Abstract. Includes bibliographical references (p. 89-103).

Honors Project--Smith College, Northampton, Mass., 2009. / Includes bibliographical references (p. 49-50).

Thesis (M.A.) -- University of Montana, 2008. / Title from author supplied metadata. Description based on contents viewed on July 15, 2009. Includes bibliographical references.

Thesis (doctoral)--Universität, Trier, 2001. / Includes bibliographical references.