Pretoria, South Africa

Tshwane University of Technology
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.

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Hamman J.H.,Tshwane University of Technology
Marine Drugs | Year: 2010

Chitosan has been the subject of interest for its use as a polymeric drug carrier material in dosage form design due to its appealing properties such as biocompatibility, biodegradability, low toxicity and relatively low production cost from abundant natural sources. However, one drawback of using this natural polysaccharide in modified release dosage forms for oral administration is its fast dissolution rate in the stomach. Since chitosan is positively charged at low pH values (below its pK a value), it spontaneously associates with negatively charged polyions in solution to form polyelectrolyte complexes. These chitosan based polyelectrolyte complexes exhibit favourable physicochemical properties with preservation of chitosan.s biocompatible characteristics. These complexes are therefore good candidate excipient materials for the design of different types of dosage forms. It is the aim of this review to describe complexation of chitosan with selected natural and synthetic polyanions and to indicate some of the factors that influence the formation and stability of these polyelectrolyte complexes. Furthermore, recent investigations into the use of these complexes as excipients in drug delivery systems such as nano- and microparticles, beads, fibers, sponges and matrix type tablets are briefly described. © 2010 by the authors; licensee MDPI.

Agency: European Commission | Branch: H2020 | Program: RIA | Phase: WATER-5c-2015 | Award Amount: 2.99M | Year: 2016

This project focuses on a major challenge in African countries: In the 15 sub-Saharan African countries 108 million people have limited or even no access to clean water. The SafeWaterAfrica project will research and develop an autonomous and decentralized water treatment system for rural and peri-urban areas which is highly efficient in the degradation of harmful pollutants and at the same time very effective in killing microbiological contaminants. The system will be designed to provide 300 people in rural areas. With a market penetration of 3000 systems the project has the potential to supply 900,000 people within app. four years after the end of the project. The project includes capacity building and business development so that system ownership and responsibility are in the hands of the local rural communities. The joint European-African development will result in a low-cost solution easy to handle and operate. It will take into account the specific cultural aspects of the region and will be designed for operation with local staff and in the responsibility of local communities or local water service providers, respectively. These Made in Africa systems will therefore have a high level of acceptance in the rural areas which promotes the implementation of the technology. Ten transdisciplinary partners from Europe and Africa, assisted by eight enterprises and organisations in the Advisory Board, will work jointly over a project duration of 42 months to adapt a specific European water treatment technology into an African water treatment system solution. Besides, SafeWaterAfrica will generate the technological basis for innovative business models related to the development of water treatment products, which are produced, installed, operated and maintained in Africa. The resulting creation of new jobs will contribute to the social well-being and will promote economic growth in the rural and peri-urban areas of the southern African countries.

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.

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.

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.

Olanrewaju O.A.,Tshwane University of Technology | Jimoh A.A.,Tshwane University of Technology
Renewable and Sustainable Energy Reviews | Year: 2014

Presently, there are huge challenges in the presence of the global energy sector, especially in the energy intensive industries that entail a huge collection of energy use, which makes energy security a vital worry. This study analyses various energy models, taking into consideration their various gaps which led to the development of an integrated model for assessing energy efficiency potential in the industrial sector. The resulting developed model will not only serve as a tool for long-term planning to ensure that energy supply is available to meet the demands of targeted economic growth, it will also give policy-makers in the industrial energy management an alertness on how to monitor, control and manage energy consumption. © 2013 Elsevier Ltd. All rights reserved.

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: 2010-06-15

This invention relates to relates to silicon light emitting devices (SiLEDs), and its application into current Complementary Metal Oxide Semiconductor (CMOS) technology, as well into future Silicon on Insulator (SOI) technology. According to the invention, a silicon based light emitting device is designed to operate by means of avalanche carrier multiplication and emitting at the below threshold wavelength detection range for Silicon of 850 nm and such that it is compatible with CMOS silicon nitride, silicon oxi-nitride and polymer waveguide technology. This favours diverse electro-optical system applications such as electro-optical couplers, fast data transfer on and from chip, various optical interconnect configurations as well as diverse on-chip sensor, fluidic and micro-optical-mechanical sensor applications. Under particular operating conditions emissions at specific wavelengths (for example the longer wavelengths) may be favoured, while in other cases tuning of the emitted radiation may be obtained.

An optical communication system is provided comprising of a three terminal silicon based light emitting device operating by means of avalanche carrier multiplication and emitting at the below threshold wavelength detection range for Silicon of 850 nm; a low loss optical waveguide operating in the below threshold wavelength detection range for Silicon of 850 nm; and an optical detector, wherein a complete and all-silicon optical communication system is formed being capable of transferring electrical signals in terms of optical intensity variations, such intensities then being propagated through the waveguide and being detected by the optical detector; and being converted back to electrical signals. In a particular mode of operation of the system, wavelength modulation may be obtained. In other applications, transponding action and optical amplification may be obtained.

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.

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