Quality of work life and job embeddedness as predictors of turnover intentions among academic staff at selected Universities in the Eastern cape province of South Africa
- Authors: Tendai , Tichangwa
- Date: 2019
- Subjects: Employee retention Organizational behavior Work -- Psychological aspects
- Language: English
- Type: Thesis , Doctoral , D.Com (Industrial Psychology)
- Identifier: http://hdl.handle.net/10353/19153 , vital:39873
- Description: Rapid higher education change in South Africa has adversely affected academics job experiences, resulting in high academic staff turnover. Despite the extant literature on the impact of higher education change, few studies have assessed how higher education change has influenced academics‟ quality of work life (QWL), job embeddedness (JE) and intention to quit (ITQ). This study investigated academic staff QWL and JE as predictors of their ITQ. A sample of 250 teaching staff (n = 250) was selected from two universities in the Eastern Cape province of South Africa using quota sampling. Data were gathered using questionnaires and analysed using descriptive (frequency distributions and measures of central tendency and variability) and inferential (Pearson correlation, significance testing and regression analysis) statistical methods. The findings confirmed the hypothesised significant negative relationships of QWL and JE with ITQ. Partial evidence suggested that QWL and JE combined explained significantly more ITQ variance than both variables did separately. JE did not moderate the QWL-ITQ association, but explained substantially greater variance in ITQ than QWL did. The sample registered high QWL and moderate JE and ITQ levels. Acceptable instrument validity and reliability were reported. The findings suggest that intrainstitutional factors somewhat mitigate the adverse effects of higher education change on academics‟ QWL, JE and ITQ and a need to enhance JE aspects, in particular, to reduce academic staff turnover intentions and behaviour. Recommendations are offered for future policy, research and practice.
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- Date Issued: 2019
Electrospun fibre based colorimetric probes for biological molecules
- Authors: Mudabuka, Boitumelo
- Date: 2014
- Subjects: Nanofibers , Vitamin C , Dopamine
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4535 , http://hdl.handle.net/10962/d1016354
- Description: The thesis reports the use of electrospun nanofibres as a platform for the development of colorimetric probes. Three colorimetric probes in the form of electrospun nanofibre test strips were developed for the selective detection of ascorbic acid and dopamine because they are crucial biomolecules for physiological processes in human metabolism and usually coexist in biological samples. The simultaneous detection of the biomolecules is very important as their abnormal concentration levels would lead to diseases such as Parkinson's and schizophrenia. Different methods of incorporating detector agents into the nanofibre were exploited for the detection of the biomolecules. The methods included physical incorporation of nanoparticles, covalent bonding of ligand/dyes through surface modification of the fibres. The first colorimetric test strip for ascorbic acid was based on copper-gold alloy nanoparticles prepared in-situ and hosted in nylon6. The test strip showed selectivity in detecting ascorbic acid in the pH range 2 – 7. The suitability of fibres in hosting copper-gold alloy nanoparticles for the colorimetric detection of ascorbic acid was investigated using nylon6, poly(vinyl benzyl chloride)-styrene and cellulose acetate based test strips. All the test strips exhibited leaching and the nylon6 based test strip was found to be thermally stable up to 60 ˚C. The colorimetric performance of the test strips was maintained and neither was colour decay exhibited after 10 months of storage in a shelf. The test strip achieved an eye-ball limit of detection of 1.76 x10-2 mg L-1 and its suitability was demonstrated by the determination of ascorbic acid in fruit juices, urine, serum, and vitamin C tablets. The second colorimetric test strip for ascorbic acid and dopamine employed prussian blue synthesised in-situ in nylon6. Ascorbic acid turned the deep blue test strip to light blue at pH 3, and a faded navy blue colour at a pH range of 6 - 7 while dopamine changed the strip to purple at the same pH range. The versatility of the test strip was demonstrated by detecting ascorbic acid in commercial fruit juices as well as by detecting ascorbic acid as well as dopamine in fortified urine. The eye-ball detection limit of the Prussian blue test strip for ascorbic acid and dopamine was 17.6 mg L-1 and 18.9 mg L-1, respectively. The third method involved a covalent approach, where poly(vinylbenzyl chloride) nanofibers were post functionalised with 2-(2′-pyridyl)-imidazole and iron(III) for the selective detection of ascorbic acid and dopamine. The eye-ball detection limit for ascorbic acid and dopamine was 17.6 mg L-1 and 18.9 mg L-1, respectively. The test strip was selective for dopamine, but the detection of ascorbic acid suffered from interference by glutathione. The application of the test strips was nevertheless demonstrated by the detection of ascorbic acid in fruit juices and dopamine in fortified urine. The developed test strips employing the three approaches were applied without sample pre-treatment and use of supporting equipment.
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- Date Issued: 2014
Computer modelling of pyrotechnic combustion
- Authors: Taylor, Steven John
- Date: 1996
- Subjects: Combustion -- Computer simulation
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4426 , http://hdl.handle.net/10962/d1006913
- Description: One of the most important industrial uses of pyrotechnic compositions is as delay fuses in electric detonators. Many factors influence the rate of burning of such fuses. These include (a) the primary choice of chemical components, followed by (b) the physical properties of these components, particularly the particle-size and distribution of the fuel, (c) the composition of the system chosen and (d) the presence of additives and/or impurities. A full experimental study of the influences of even a few of these factors, while attempting to hold other potential variables constant, would be extremely time consuming and hence attention has been focused on the possibilities of modelling pyrotechnic combustion. Various approaches to the modelling of pyrotechnic combustion are discussed. These include:- (i) one-dimensional finite-difference models; (ii) two-dimensional finite-element models; (iii) particle-packing considerations; (iv) Monte Carlo models. Predicted behaviour is compared with extensive experimental information for the widely-used antimony/potassium permanganate pyrotechnic system, and the tungsten /potassium dichromate pyrotechnic system. The one-dimensional finite-difference model was investigated to give a simple means of investigating the effects of some parameters on the combustion of a pyrotechnic. The two-dimensional finite-difference model used similar inputs, but at the expense of considerably more computer power, gave more extensive information such as the shape of the burning front and the temperature gradients throughout the column and within the casing material. Both these models gave improved results when allowance was made for autocatalytic kinetics in place of the usual assumption of an "order-of-reaction", n ≤ 1. The particle-packing model investigated the qualitative relationship between the maximum burning rate of a pyrotechnic system and the maximum number of contact points (per 1.00 g composition) calculated for that system. Qualitative agreement was found for those systems which are presumed to burn mainly via solid-solid reactions. The Monte Carlo model investigated the effect of the random packing of fuel and oxidant particles on the variability of the burning rate of a pyrotechnic composition.
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- Date Issued: 1996
An investigation into the components of motivation so far as these determine employee stability and work satisfaction amongst Europeans and Africans engaged in the same occupational grading in the copper mining industry of Zambia
- Authors: Coetzee, J A G
- Date: 1968
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3383 , http://hdl.handle.net/10962/d1013334
- Description: From introduction: The aim of this study is to analyse the motivational system, so far as this regulates and orients the stability and work satisfactions of Europeans and Africans, in a supervisory occupational category engaged in industrial-mining in the Copper Mining Company of Rhokana, Zambia , during a period of six years, ending in 1963 .
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- Date Issued: 1968