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Cowan, Donald A. (Elsevier, 2004)[more][less]
Abstract: The newly isolated hyperthermophilic archaeal strain 121 grows slowly at 121 8C and even survives short periods at 130 8C. This is another organism that grows best at temperatures well in excess of 100 8C! We should not be astonished so much by the numerical increments but by the biochemical implications of this fact, and we should be excited by the scope provided by this and similar organisms to further our understanding of the evolution and adaptation of molecular structures and systems. And what about the upper limit of life? It appears improbable that the end-point of this search is represented by strain 121. The consensus view is that the true upper limit, where the energetic burden imposed by molecular repair and resynthesis becomes unsustainable, will probably lie in the region of 140–150 8C URI: http://hdl.handle.net/10566/147 Files in this item: 1
CowanUpperTemperature2004.pdf (331.8Kb) -
Babajide, Omotola; Petrik, Leslie; Musyoka, Nicholas; Amigun, Bamikole; Ameer, Farouk (Slovnaft VÚRUP, 2010)[more][less]
Abstract: South Africa is largely dependent on the combustion of coal for electricity production; Eskom’s coalfired power stations consume approximately 109 million tons of coal per annum, producing around 25 million tons of ash, to supply the bulk (93%) of South Africa’s electricity. The management of this fly ash has been a concern with various approaches for its beneficial use being investigated. This work presents the results of transesterification reaction using sunflower oil as feedstock with methanol and class F fly ash catalyst derived from a coal fly ash dump in South Africa to produce methyl esters (biodiesel). The fly ash based catalyst was prepared using the wet impregnation procedure with different loadings of potassium. This was characterized by powder X-ray diffraction (XRD), FTIR spectroscopy. The XRD patterns obtained indicated that the structure of the support gradually deformed with an increase in the loading and the extent of decomposition of KNO3 varied with the amount of loading. The influence of various reactions parameters such as loading amount of active components, methanol: oil ratio, reaction time, temperature and catalyst deactivation was investigated. The fly ash based catalyst loaded with 5% wt KNO3 at a reaction temperature of 160ºC exhibited maximum oil conversion (86.13%). The biodiesel synthesized was tested and important fuel properties of the methyl esters (Biodiesel) compared well with ASTM biodiesel standard URI: http://hdl.handle.net/10566/574 Files in this item: 1
BabajideBiodieselProduction2010.pdf (597.5Kb) -
Chetty, Marshini; Tucker, William D.; Blake, Edwin H. (Telkom, 2003)[more][less]
Abstract: There is a great disparity between those who have access to Information and Communication Technologies (ICTs) and those that do not. This phenomenon forms part of the Digital Divide. Many ICTs may be used to help overcome this divide if they are applied in a useful way, providing locally applicable content and services. Critical Action Research (CAR) is an approach used to develop such applications. CAR aims to empower people by involving them in the development process. Using CAR, this project investigates how Voice over IP (VoIP) may be applied in a productive way in an underserviced community. VoIP is an ICT used for sending voice over packet switched networks using Internet Protocol. It can be used to integrate data and voice to produce multimedia applications. In South Africa (SA), VoIP may only be provided by Telkom, the Second National Operator and the Under-Serviced Area Licensees. Using CAR and VoIP, an application is being developed to service a specific need of a particular rural community. The application will either provide a service to a small rural business or aid the provision of healthcare in rural areas. The project evaluates how well CAR integrates with a normal Software Development Lifecycle and makes policy recommendations for the use of VoIP in rural SA. URI: http://hdl.handle.net/10566/479 Files in this item: 1
ChettyTuckerBlakeDigitalDivide2003.pdf (35.78Kb) -
Gibbons, Mark J.; Sulaiman, Amina; Hissman, K.; Schauer, J.; Wickens, Patti; McMillan, Ian (NISC and Taylor & Francis, 2000)[more][less]
Abstract: A semi-quantitative assessment is made of the animals observed in archived videotapes taken from the research submersible Jago, during diamond mining and exploratory surveys off the mouth of the Orange River on the west coast of southern Africa (28° IS'S, 29°11 'S) in November 1996. The seabed environment is described and nekton associations with substratum features are identified. The area is characterized by heterogeneity to its physical and biological struture. The variety of observed nekton is low, and communities are dominated by goby Sufflogobius bibarbatus, juvenile hake Merluccius spp. and cuttlefish Sepia spp. (on soft substrata), as well as false jacopever Sebastes capen sis and kingklip Genypterus capensis (on rocky substrata). URI: http://hdl.handle.net/10566/419 Files in this item: 1
GibbonsDemersalNekton2000.pdf (501.8Kb) -
Glaser, Meryl; Tucker, William D. (Telkom, 2001)[more][less]
Abstract: A Teldem provides text-based telephony services to the deaf. Despite an array of text-based communications mechanisms on the web, the Teldem is the only means of synchronous telecommunication available to a deaf person. We examine a human-assisted relay that provides a bridge between the deaf and the hearing, and then propose several additional bridges. These bridges take advantage of both standard and cutting edge technologies. We present each bridge's impact on the deaf with respect to synchrony, connectivity, independence, and the Digital Divide. It is hoped that by deploying trials for each bridge, we can eventually provide the deaf with equal access. URI: http://hdl.handle.net/10566/613 Files in this item: 1
GlaserTucker-SATNAC2001.pdf (146.9Kb)
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Now showing items 94-98 of 98