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Activity and selectivity of transition metal (Fe, Mo and W) carbides in the Fischer-Tropsch synthesisPatterson, Veronica A January 2007 (has links)
Includes bibliographical references (leaves 99-107). / This study focused on the Fischer-Tropsch activity and selectivity of transition metal (iron, molybdenum and tungsten) carbides. The carbide catalysts were prepared by a temperature programmed method. The properties of the materials were characterised by X-ray diffraction (XRD), transmission electron microscopy (TEM), BET measurements and temperature programmed desorption of carbon monoxide (CO-TPD). The performance of the materials was tested in a Berty reactor. A reduced, precipitated iron oxide catalyst was used as a reference catalyst.
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The transfer of energy technology : a case study of hydropower in LesothoNtlamelle, Moses H January 2003 (has links)
Bibliography: leaves 81-85. / This work investigates strategies for the transfer of energy technologies so as to develop the necessary capability for adapting and adopting such technologies in the recipient country using the transfer of hydropower technology to Lesotho as a case study. The work reviewed the literature on this subject as a background to the development of a technology transfer framework that formed the basis of the analysis. The framework was tested using the Muela hydropower project in Lesotho. Existing mini-hydropower projects in Lesotho were also reviewed to identify possible lessons from them regarding objective of this study.
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The development of an energy education package for secondary schoolsOxenham, Peter Eric Clinton January 1994 (has links)
Includes bibliographical references. / The central objective of this project was to develop a package of energy education workshops for secondary schools. The package contains nine energy workshops. Each workshop comprises a teacher's guide and a student worksheet. The package production process included choosing an education methodology, reviewing energy themes for selection as workshop topics and evaluating the energy workshop package. This dissertation provides insight into the processes of producing this package. My participation in the Community Education Resource's Masters programme introduced he goal of producing university resources in formats which are accessible to a broader audience. Energy themes for the workshops were drawn from a review of existing resources, particularly those f the Energy for Development Research Centre, and were selected for their relevance to energy as an agent of development, energy production and environmental concerns, energy policy formulation and vocational interest.
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Crystallisation of PFA glassesEmms, S January 1994 (has links)
Bibliography: leaves 79-81. / Glasses with various compositions, falling in the CaO-AI20rSi02 and MgO-CaOAI20rSi02 systems were made, using pulverised fuel ash and silica, hydrated lime, kaolin and magnesium carbonate. Titania or ferric oxide and chromia were used as nucleants. Various crystallisation heat treatments were carried out and the nucleation and crystallisation behaviour was studied. A minimum MgO:CaO was found to be necessary for bulk nucleation to occur. The activation energy for viscous flow decreased with increased MgO:CaO ratios. This was accompanied by an increase in the surface crystal growth rates and a decrease in the activation energy for surface crystal growth. Titania also lowered the activation energies for viscous flow and surface crystal growth and caused an increase in the surface crystal growth rates.
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Household energy information management system for Africa : a Ugandan case studyOpio, Peter January 2003 (has links)
Bibliography: leaves 86-89. / An information database built through regular planned surveys in a comprehensive manner is the objective of this study. A foundation for periodic up-date of household energy is necessary and requires a proper institutional or structural set up that gives priority to household energy issues. This study explores the fundamental need to shift away from the current ad hoc surveys to a more reliable, systematic, comprehensive and financially effective way of conducting household energy surveys to generate household energy information that is representative of national picture and which supports effective planning and policy-making. Promotion of the importance of the household energy sector in terms of social equity and improved living standards is vital for investors, developers, financiers and policy-makers and planners to improve the sector. Thus the study addresses the appropriate way of obtaining comprehensive household energy information and harmonized data collection methodology through cooperation in information exchange amongst African countries to achieve comparability of data for a common African energy database.
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Effects of thermomechanical processing on microstructure and hardness profiles in AA6061 platesHapazari, Innocent January 2003 (has links)
Includes bibliographical references. / Effects of rolling variables - strain (?), strain rate (?) and temperature (T) - on grain structure and hardness evolution in AA6061 plates were investigated by simulating the rolling process using plane strain compression (PSG). Particular emphasis was exerted on understanding the impact of the variables on the overall mean grain size and hardness, as well as how they influence the grain size and hardness profiles through the thickness of the rolled plates. Prior to PSG investigations, the grain size and hardness profiles of the supplied material (transfer and finished plates) were determined using a Reichert MeF3A optical microscope and Vickers hardness tester. No significant grain size variations were observed through the thickness of transfer plate. On the contrary, finished plates exhibited grain size gradients, with grain size progressively decreasing from the surface to the centre of the plate thickness.
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Production of mid-chain branched detergent-range olefins over shape-selective acid catalystsSumani, Mmontshi Lebohang Oliver January 2006 (has links)
Includes bibliographical references (leaves 78-83). / For the purpose of producing mid-chain mono-methyl branched olefins, a range of acid catalysts (MFI, BEA, TON and amorphous silica-alumina) were screened for the dimerization of 1-hexene, under generally mild conditions, viz. 150 - 170°C, 20 - 40 bar and 1 - 4h-1 WHSV. It was postulated that shape-selective catalysts with defined pore sizes might improve selectivity towards mid-chain mono-methyl branched olefins. Such olefins are potential feedstocks for selectively branched detergents which have improved surfactant properties while retaining good biodegradability. NMR and GC-MS analyses of hydrogenated dimer product fractions indicated that all catalysts produce branched products, and that these products are predominantly multi-branched (i.e. with two or more branches per C12 molecule). Overall, the findings of this study suggest a similar degree of branching of two for all catalysts. Selective poisoning of the external surface of the MFI-90 catalyst using bulky bases effectively eliminated the catalytic activity, suggesting that in the case of MFI zeolite, the hexene dimerization reaction occurs largely (if not exclusively) on the external crystal surfaces which are not shape-selective.In conclusion, BEA and amorphous silica-alumina pore being too large to induce shape selectivity and MFI and TON dimerization being limited to the external, non-selective, surface sites, the production of mono-methyl branched 1-hexene dimers was not accomplished.
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The use of life cycle assessment in the evaluation of environmental performance in the base metal refining industryForbes, Patricia Belinda Crosby January 1999 (has links)
Includes bibliographical references. / In the last decade, life cycle assessment has come into consideration as an environmental decision support tool for the design and operation of industrial processes. The usefulness of this technique for the purpose of environmental management was assessed by means of a case study carried out at the base metal refinery of impala Platinum Limited. An assessment was first carried out on the historic performance of the process. This was then extended to evaluate some possible impacts of future changes in operating practice and technology.
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The effect of CO2 on the activation of a precipitated iron Fischer-Tropsch catalystHarding, Samantha January 2000 (has links)
Bibliography: leaves 88-92. / The effect of CO2 on the activation of a precipitated iron catalyst by hydrogen and carbon monoxide was investigated. The iron-based catalyst was precipitated from a mixture of iron nitrate and copper nitrate then bounf by the addition of potassium waterglass to achieve a final catalyst precursor composition of 3.8K2O/4.8Cu/26.0SiO2/100Fe. The activation procedures used four different gas compositions.
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Combustion characteristics of South African grown fuelwoodsDavis, Mark January 1990 (has links)
Bibliography: leaves 138-144. / The principle objective of this investigation was to establish a methodology to compare and rank fuelwoods. This methodology would allow a wide range of tree species to be compared and ranked according to their combustion properties. Such a comparison would assist in the selection of species for woodlot development. This investigation attempted to examine the combustion kinetics of small samples in an attempt to achieve the stated aim. Initially a literature review was performed. This covered anecdotal information on fuelwood preferences, an overview of wood composition, structure and combustion, and an in depth review of existing work on small sample combustion.
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