http://hdl.handle.net/10204/943 2013-05-24T02:12:11Z 2013-05-24T02:12:11Z Roro, KT Tile, N Mwakikunga, B Yalisi, B Forbes, A http://hdl.handle.net/10204/6711 2013-05-03T21:55:14Z 2012-05-01T00:00:00Z

Title: Solar absorption and thermal emission properties of multiwall carbon nanotube/nickel oxide nanocomposite thin films synthesized by sol-gel process Authors: Roro, KT; Tile, N; Mwakikunga, B; Yalisi, B; Forbes, A Abstract: Multiwall carbon nanotubes (MWCNTs)/nickel oxide (NiO) nanocomposites were successfully prepared by a sol–gel process and coated on an aluminium substrate. The MWCNTs were chemically functionalized and then added into NiO alcogels, and magnetic stirred for homogeneous dispersion into the NiO matrix solution. The morphology of the resulting nanocomposite thin films showed that the MWCNTs were embedded in the NiO nano-particle matrix, while HRTEM confirmed that the MWCNTs were surrounded by the NiO nano-particles. Raman spectra for functionalized MWCNTs displayed a red shift from the pristine MWCNTs suggesting successful purification/functionalization. The spectrum for the MWCNTs/NiO nanocomposite indicated the presence of both the TO and LO phonons of NiO, and the D and G bands of the MWCNTs. Red and blue shifts of the NiO phonons and the MWCNT phonons suggested that the vibrational properties of both materials were changed to form new nanocomposite vibrational properties. Despite unoptimized layer thickness and composition, the solar absorptance of the functionalized MWCNTs/NiO nanocomposite films was 0.84 (for a single layer). The thermal emittance at 100 °C was approximately 0.2. These results suggest that MWCNTs/NiO nanocomposite materials are suitable for solar thermal applications. Description: Copyright: 2012 Elsevier. This is an ABSTRACT ONLY. The definitive version is published in Materials Science and Engineering: B, vol. 177(8), pp 581–587

2012-05-01T00:00:00Z Burton, S Cohen, B Harrison, S Pather-Elias, S Stafford, W Van Hille, R Von Blottnitz, H http://hdl.handle.net/10204/6692 2013-04-18T21:55:17Z 2012-07-01T00:00:00Z

Title: Energy from wastewater - a feasibility study and guide for: Technology developers and researchers, industry and wastewater generators and policy makers Authors: Burton, S; Cohen, B; Harrison, S; Pather-Elias, S; Stafford, W; Van Hille, R; Von Blottnitz, H Abstract: This guide is based on a study funded by the Water Research Commission with the purpose of determining the feasibility of developing technologies for energy recovery from wastewater. A full technical report is available for further reference (WRC report no 1732/1/09). The availability of clean, renewable fuels is well recognised to be core to sustainable economic growth. The use of wastewater as a renewable energy resource has been poorly exploited to date particularly in developing countries such as South Africa. Wastewaters as renewable sources of energy are valuable to supplement and/or replace non-renewable sources, reduce the environmental burden of conventional power generation and provide the added benefit of enhanced waste processing. The study reviewed the available literature and surveyed international and national practice in energy recovery from wastewater in order to identify the most significant potential for new research and innovation. A survey of potentials for energy from wastewater in South Africa served to identify which types of substrates are available in significant amounts. The project also included a set of case studies that show what factors to consider in developing energy from wastewater projects. Workshops were held to provide opportunities for consultation with stakeholders in the fields of wastewater treatment and technology development, in order to determine areas where technical and application problems might exist (WRC report no1732/1/09). This guide makes recommendations relevant to the R&D sector regarding recovery of energy from wastewater. It also seeks to provide information about directions which would be useful to South Africa’s research community by identifying areas where R&D are needed, and by highlighting areas to which the WRC might direct funding in future. Description: Copyright: 2009 South African Water Resource Commission. This is an ABSTRACT ONLY. The definitive version is published in WRC, Report No. TT 400/09.

2012-07-01T00:00:00Z Amigun, B Von Blottnitz, H http://hdl.handle.net/10204/6647 2013-04-11T21:55:15Z 2011-10-01T00:00:00Z

Title: Operating cost analysis of an annexed ethanol distillery in a rural, landlocked African country Authors: Amigun, B; Von Blottnitz, H Abstract: Given the high cost of crude oil, uncertainties regarding future reserves as well as the phenomenon of global warming, alternative fuels such as bioethanol need to be developed and deployed. This work presents an economic analysis (operating cost analysis) of one annexed African distillery operating in a landlocked and rural location. Specifically, the study attempts to analyze the impacts that some of the critical factors influencing bioethanol production will have on its viability and also present an analysis of the breakdown of the operating costs of the distillery, in an equation format to enable easier and more rapid use of the data in numerical and economic models, and in the preliminary design and optimization of bioethanol plants. The cost of ethanol production was estimated at $19.57/HL with cost of feedstock (molasses ‘‘type C’’) constituting about one third of the production cost. The study also identified other major, intermediate, and minor input factors, which can provide insights to both the possible barriers to implementation that should be overcome, and on the technological improvement options that should be stimulated by research and development in ethanol industry. Finally, from the operating cost analysis of the annexed distillery, it emerged that the factorial approach to estimation is principally a sound one, with no indication of untypical cost items. Some of the typical cost items do however display ratios to the base cost that are outside of previously reported limits. Description: Copyright: 2011 Wiley-Blackwell. This is an ABSTRACT ONLY. The definitive version is published in Environmental Progress & Sustainable Energy, vol. 30(3), pp 500-515 http://onlinelibrary.wiley.com/doi/10.1002/ep.10489/pdf

2011-10-01T00:00:00Z Mashoko, L Mbohwa, C Thomas, VM http://hdl.handle.net/10204/6334 2012-11-20T21:55:22Z 2013-01-01T00:00:00Z

Title: Life cycle inventory of electricity cogeneration from bagasse in the South African sugar industry Authors: Mashoko, L; Mbohwa, C; Thomas, VM Abstract: The South African sugar industry has a potential for cogeneration of steam and electricity using bagasse. The sugar industry has the potential to generate about 960 MW per year from bagasse based on the average of 20 million tons of sugar cane crushed per year. Renewable energy sources like bagasse are generally regarded as cleaner energy sources as opposed to coal-derived energy. However, the environmental benefits of power production from bagasse must be verified using a systematic scientific methodology. This study develops the life cycle inventories for bagasse power production in South Africa. The life cycle inventory can help to evaluate the environmental impacts of the cogeneration throughout the life cycle. The data for this inventory stage of the research was supplied by the sugar industry, and the analysis mostly uses South African data in the inventory stage. The study presents life cycle inventories based on a functional unit of 1 GWh of bagasse-derived electricity produced in the South African sugar industry. A comparison of the current generating output with a proposed higher output shows that more energy can be produced in addition to reduced inventory levels and this has the potential to improve environmental performance of bagasse power generation in South Africa. Description: Copyright: 2013 Elsevier. This is an ABSTRACT ONLY. The definitive version is published in the Journal of Cleaner Production, vol. 39, pp 42-49

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