Time filter

Source Type

Pretoria, South Africa

Tshwane University of Technology is a higher education institution in South Africa that came into being through a merger of three technikons — Technikon Northern Gauteng, Technikon North-West and Technikon Pretoria.As the number of students registering annually grows rapidly, records show that Tshwane University of Technology caters for approximately 60,000 students and it has become the largest residential higher education institution in South Africa. Wikipedia.

Funston P.J.,Tshwane University of Technology
South African Journal of Wildlife Research | Year: 2011

Lions (Panthera leo) that kill livestock around the Kgalagadi Transfrontier Park have been persecuted for decades. The impact of this on the population ecology and long-term survival probability of this population has been unknown. This was largely due to a lack of basic population information. The results of a three-year intensive study from 1998 to 2001 into the population characteristics of Kgalagadi lions are presented. Kgalagadi lions exhibit similar population characteristics to most other lion populations and show little to no effect of anthropogenic mortality. Differences from other populations include exceptionally large home ranges (1462 ± 388 km 2), which are however related to prey biomass. The adult sex ratio was more biased towards females than is typical, which is possibly a product of both ecological and anthropogenic influences. Cub survival is related to rainfall conditions and the number of adult lionesses in groups with cubs, but not to the number of adult males defending each pride. Owing to low prey abundance prides form stable subgroups typically containing two adult lionesses for long periods once cubs have reached one year of age. Kgalagadi lions show similar dispersal patterns to other lion populations with resident prey. Subadults in boundary prides suffer high mortality levels in response to livestock depredation. Males are more likely to become habitual livestock raiders, which ultimately leads to them being killed. Source

Diesel engines provide the major power source for transportation in the world and contribute to the prosperity of the worldwide economy. However, recent concerns over the environment, increasing fuel prices and the scarcity of fuel supplies have promoted considerable interest in searching for alternatives to petroleum based fuels. Based on this background, the main purpose of this investigation is to evaluate clove stem oil (CSO) as an alternative fuel for diesel engines. To this end, an experimental investigation was performed on a four-stroke, four-cylinder water-cooled direct injection diesel engine to study the performance and emissions of an engine operated using the CSO-diesel blended fuels. The effects of the CSO-diesel blended fuels on the engine brake thermal efficiency, brake specific fuel consumption (BSFC), specific energy consumption (SEC), exhaust gas temperatures and exhaust emissions were investigated. The experimental results reveal that the engine brake thermal efficiency and BSFC of the CSO-diesel blended fuels were higher than the pure diesel fuel while at the same time they exhibited a lower SEC than the latter over the entire engine load range. The variations in exhaust gas temperatures between the tested fuels were significant only at medium speed operating conditions. Furthermore, the HC emissions were lower for the CSO-diesel blended fuels than the pure diesel fuel whereas the NO. x emissions were increased remarkably when the engine was fuelled with the 50% CSO-diesel blended fuel. © 2010 Elsevier Ltd. Source

Bolaji B.O.,Abeokuta Federal University of Agriculture | Huan Z.,Tshwane University of Technology
Renewable and Sustainable Energy Reviews | Year: 2013

This paper presents natural refrigerants as the ideal, environmentally friendly refrigerants and the ultimate solution to the problems of ozone depletion and global warming. HFC refrigerants are currently the leading replacement for CFC and HCFC refrigerants in refrigeration and air-conditioning systems. However, they are equally foreign to nature like CFCs and HCFCs, consequently, strong basis for the need to embrace the use of natural refrigerants as replacement for the halocarbon refrigerants was provided. This paper also analyses potentials of various natural refrigerants and their areas of application in refrigeration and air-conditioning systems. Natural refrigerants especially hydrocarbons and their mixtures are miscible with both mineral oil used in R12 and poly-ol-ester oils used in R134a systems. Also, with exception of ammonia, they are fully compatible with all materials traditionally used in refrigeration systems. Finally, this paper has revealed that natural refrigerants are the most suitable long time alternatives in refrigeration and air-conditioning systems. © 2012 Published by Elsevier Ltd. Source

Tshwane University of Technology | Date: 2010-06-15

The present invention relates to a sensor device. More particularly, the invention relates to a CMOS-based micro-optical-electromechanical-sensor (MOEMS) device with silicon light emitting devices, silicon waveguides and silicon detectors being fabricated using current Complementary Metal Oxide Semiconductor (CMOS) technology or Silicon on Insulator (SOI) technology. According to the invention there is provided a sensor comprising: a Silicon-based light emitting structure; an integrated electro-optical mechanical interface structure that is capable to sense mechanical deflections; an integrated electronic driving and processing circuitry so as to detect physical parameters such as vibration, motion, rotation, acceleration.

Tshwane University of Technology | Date: 2011-03-18

A process for treating impure water includes adding magnesium hydroxide and/or ammonium hydroxide to the water. This neutralizes the impure water and reacts with dissolved metals in the water. The metals are precipitated as metal hydroxides/oxides, which are removed from the water. Thereafter barium hydroxide is added to the water. The barium hydroxide reacts with dissolved sulphates to produce barium sulphate and, when magnesium hydroxide is used, with dissolved magnesium, to produce magnesium hydroxide. Barium sulphate and, when present, magnesium hydroxide are removed from the water. When ammonium hydroxide is used, ammonia is stripped from the water. Carbon dioxide is then added to the water. The carbon dioxide reacts with dissolved calcium in the water. The calcium is precipitated as calcium carbonate, which is removed from the water.

Discover hidden collaborations