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The promotional effect of copper on alumina and activated carbon supported NIMO hydrodeoxygenation catalysts
Full text linkThe rapid depletion of oil reserves and the environmental issues caused by heavy reliance on fossil fuels throughout society's explosive growth have forced the world to find alternative sources of fuel. Fossil fuels for transportation and industrial purposes can be satisfactorily replaced with biofuels such as biodiesel and bioethanol liquid fuels. Unfortunately, use of these bioderived fuels is discouraged because of their high concentration of oxygen-containing compounds. Several studies have been conducted to remove the oxygen-containing compounds, most of which have focused on removing aromatic oxygenated compounds due to the difficulty of removing oxygen from these compounds. Hydrodeoxygenation (HDO) catalysts are a crucial part of the HDO process. However, the currently employed hydrodeoxygenation (HDO) catalysts suffer from deactivation due to the high oxygen content in bio-oil, thus producing fuel sources that cannot comply with the required fuel quality standards. Unsupported NiMo and CuNiMo catalysts were synthesized and characterized to understand the interactions between the metals (Ni, Mo, and Cu) in the catalysts and guide on understanding the use of Cu as an additional promoter metal. Single crystal XRD revealed the interaction between Ni and Mo showing how octahedral MoO surrounds Ni forming an octahedral sphere. Other characterization techniques such as FT-IR, UV/Vis, SEM-EDS, TEM, XRD, ICP, and TGA/DSC were also employed to elucidate the relationships. The alumina and activated carbon supported NiMo/γ-Al2O3, NiMo/AC, CuNiMo/γ-Al2O3, and CuNiMo/AC catalysts were also prepared and characterized using similar techniques to further understand the idea of promoting using copper and the possibility of migrating from the conventional γ-Al2O3 support which suffers deactivation due to dealumination. It was observed that the general uptake of metals is much higher for the γ-Al2O3 support compared to the AC support. Diffuse reflectance spectroscopy showed better dispersion of Ni and Mo in the γ-Al2O3 catalyst when Cu was introduced. The catalysts were also evaluated in the HDO of phenol model fuel and the catalytic activity followed the trend: CuNiMo/γ-Al2O3 (46.1%) > NiMo/γ-Al2O3 (42.1%) > NiMo/AC (25.1%) > CuNiMo/AC (5.6%). HDO studies showed much higher improvement in catalytic activity when Cu was introduced to γ-Al2O3 supported NiMo while in the case of AC-supported NiMo, the activity was unusually lower regardless of the remarkably higher total metal content in the catalyst. Through this work, we recommend the use of Cu as a promoter in γ-Al2O3 supported NiMo catalysts for HDO. Further work is needed to fully understand the disparities observed when Cu is used as a promoter in the AC supported NiMo catalysts.Thesis (MSc) -- Faculty of Science, School of Biomolecular & Chemical Sciences, 202
The effects of seasonality on the thermal physiology of Bradypodion ventrale in Gqeberha, South Africa
Full text linkUnderstanding if species respond to seasonal changes in their environments through phenotypic flexibility in their thermal physiological variables is the first step in understanding how species may be able to cope with large scale climate change. There is a relative lack of an understanding of chameleons thermal biology and how they may respond to seasonal changes, thus the over-arching aim of this investigation was to assess whether Bradypodion ventrale, an endemic South African species, displays variation in their thermal physiological variables across the four seasons (i.e. summer, autumn, winter, and spring. My objective was to conduct a seasonal comparison of preferred body temperature (Tpref) and both the upper (CTmax) and lower (CTmin) critical thermal limits in B. ventrale. For my second objective, I conducted experiments to assess optimal performance temperature (Topt) for digestion in summer. Here, my aim was to describe the relationship between temperature and digestive performance for B. ventrale, measured as gut passage time (GP) and apparent digestive efficiency (ADE). The aims of the investigation were addressed by collecting 104 individuals of B. ventrale (n= 44 males and n= 60 females) in Gqeberha, South Africa, and quantifying their thermal physiological variables within a laboratory. The Tpref was assessed using a standard cost-free thermal gradient approach, with trials conducted within each of the seasons. The CTmin and CTmax were assessed by temporarily exposing individuals to extreme temperatures of -2 oC and 47 oC, respectively, while making use of the righting response method to assess the body temperature associated with the point where individuals could no longer right themselves, and thus would be unable to evade threats. A T-type thermocouple was used to take body temperature measurements’ by inserting the T-type thermocouple probe in to the cloaca of an individual. Sex and site type (urban vs natural) were also considered, due to previous studies noting differences in lizards thermal physiological traits and these factors, but showed no significant results. It was further hypothesized that the Tpref, CTmin, and CTmax of B. ventrale would show seasonal differences, based on the observation that lizards have displayed seasonal variation in their thermal physiological variables. The Topt for digestion was assessed by collecting 25 B. ventrale individuals from natural habitats in Gqeberha and acclimating them for 7 Days, in groups of 5, to one of 5 set temperatures (22 oC, 25 oC, 29 oC, 31 oC, and 33oC). The GP time was quantified by inserting a small pieces of colourful plastic (2 x 2 x 0.5 mm3) in to a cricket that was subsequently ingested by a VI chameleon and monitoring the length of time taken to excrete the plastic. Digestive efficiency was assessed by monitoring cricket consumption and faeces production, then making use of a bomb calorimeter to determine the energetic content and substituted the output into an equation (McConnachie and Alexander 2004) to calculate the ADE. Given previous work on reptiles showing that GP generally shows a negative relationship with temperature, it was hypothesized that GP would decrease with increasing experimental temperature. In contrast, it was hypothesized that ADE would not be influenced by experimental temperature, this was based on the finding of past studies. Overall, the study revealed that B. ventrale showed seasonal acclimation in their Tpref and CTmin, but not in their CTmax. My study found that B. ventrale displayed a higher Tpref and CTmin in summer, compared to the other seasons. In contrast, B. ventrale showed no seasonal differences in their CTmax. Furthermore, my study also showed that their digestive performance is thermally dependent at the experimental temperatures used. Gut passage time had a negative relationship with temperature, showing that GP was only significantly longer at 22 oC. Experimental temperatures did have a significant influence on the ADE of B. ventrale, who displayed inconsistent trends in their thermal dependence between the experimental temperatures. No significant difference was observed between ADE at 25 oC or ADE at 33 oC, but ADE at 29 oC was significantly lower, compared to the other experimental temperatures. Apparent digestive efficiency could not be determined at 22 oC due to the low volume of faeces produced, thus 25 oC was the lowest temperature tested for ADE. Collectively, the thermal physiological variables studied offers us some insights into the thermal niche of B. ventrale. Furthermore, the findings suggest that B. ventrale displays seasonal acclimitization in their Tpref and CTmin and a high Topt for digestion, implying that the species may be able to persist despite the predicted 1 – 2.3 oC projected temperature increase for Gqeberha, being limited only by their CTThesis (MSc) -- Faculty of Science, School of Environmental Sciences, 202
Exploring traditional healers' conceptualisations of mental illness and psychological wellbeing amongst the Xhosa people of South Africa
Full text linkIn South Africa, the use of indigenous medicine is widely known. Approximately 80-85% of black South Africans consult with traditional healers in both rural and urban communities. However, despite increased academic interest in indigenous health knowledge (IHK) in the country in recent years, the research is still limited. Previous studies exploring traditional healers’ mental health practices have mostly been done in a prescriptive manner. Whereby Western frameworks such as the Diagnostic and Statistical Manual of Mental Disorders (DSM- 5) have been presented to traditional healers and direct comparisons drawn between the DSM- 5 and their indigenous practice. This study, by virtue of its focus, aimed to explore the meaning of psychological wellbeing and what the determinants of mental illness are from a traditional healer’s perspective. It endeavoured to answer the question “How do traditional healers understand, diagnose and treat mental illness?”. The study located itself as wanting to understand African ways of viewing health and disease, without assuming or imposing superiority of biomedicine and other Western understandings. The methodology followed an exploratory-descriptive, qualitative design and adopted Lincoln and Guba's (1985) model of trustworthiness. Eight participants were recruited using snowball and purposive sampling. Data was gathered via semi-structured interviews that were on one-on-one basis and using online video and analysed using Braun and Clarke’s (2006) thematic analysis. The themes identified through the thematic analysis are: traditional healers' background and experience (trained categories and areas of specialisation; traditional healing diagnostic systems; causes and interpretation of an unwell person; traditional healing methods and practices; traditional healers' role in the community. The findings from the study suggested that traditional healers have areas of specialisation defined by their training and skills, similar to how psychologists have differing scopes of practice. There are shared aspects in the aetiology and treatment of mental illness between indigenous practices and modern psychology, including the recognition of biopsychosocial and spiritual factors, and shared treatment methods such as symbolism, dream analysis, repair of ruptures in relationships, meditation, grounding, journaling and selfcare techniques. This study argues for the importance of collaboration between indigenous and biomedical practitioners to provide holistic mental health care, and the findings of this study may provide helpful insights to mental healthcare providers giving care to African patients.Thesis (MA) -- Faculty of Health Sciences, School of Behavioural & Lifestyle Sciences, 202
Suitability of a triply periodic minimal surface lattice heat exchanger for an electrical vehicle cooling system
Full text linkMany automotive OEMs have introduced electrical vehicles (EVs) into their current and future production outputs on an accelerated basis. The many benefits of EVs are clear and evident, but it is still a comparatively new sector compared to established internal combustion engine (ICE) vehicles that have dominated the automotive landscape over the last century. Therefore, many challenges face the Design Engineer in this sector. As a result, research and development in EVs is accelerating across all component systems in contemporary automotive manufacturing. The cooling systems of EVs is an area that tends to be more complex than their ICE counterparts as there are not only more components that require regulating and cooling, but the criticality of these systems is considerably more constrained than typical internal combustion (IC) systems. EV cooling systems make use of specialist battery systems and electrical components which occupy a large amount of space within the vehicle design space and require advanced thermal control. These large number of batteries and components invariably means that EVs tend to be generally very heavy vehicles. The objective of this research is to design, simulate, manufacture and test an additively manufactured (AM) cooling system for an EV while focusing on minimizing material, consolidation of parts and enhancing heat transfer efficiency. AM allows the Design Engineer significant freedom as complex structures can be manufactured that would not typically be possible with traditional subtractive and formative methods. This additive process allows for unique, conformal and compact components to be produced, which still maintain excellent functionality. The heat exchanger design in this study investigated lattice structures, increasing the conductive surface area available for heat transfer. Various heat exchanger designs were simulated and physically tested to determine their ability to transfer heat effectively. When comparing the heat transfer performance of the AM cooling system to that of a traditionally used EV cooling system it was identified that AM heat exchangers can provide a better cooling performance relative to the traditional radiators. This research shows that, compared to a traditional radiator, a smaller and more lightweight AM heat exchanger can produce the needed thermal cooling for an EV cooling system. Thus, proving that AM is a viable option for the future of the EV industry.Thesis (MEng) -- Faculty of Engineering, the Built Environment, and Technology, School of Engineering, 202
Exploring the determinants and antecedents of an employee engagement strategy for fourth industrial revolution (4IR) employers
Full text linkRasheed, Khan and Ramzan (2013:195) state that employee engagement (EE) is considered as a “critical indicator of the success of an organisation”. EE is a subject that has been widely studied and researched, and the conclusion in most studies is that it undoubtably contributes to the success of an organisation in some way or another. In this study, the topic of EE was investigated within the context of the Fourth Industrial Revolution (4IR) work environment. This study used literature to explore the notion of EE and the impact thereof, followed by investigating shared characteristics of a 4IR employer and employee. The researcher then highlighted existing EE strategies and current, valid EE measurement tools. Thereafter, the researcher investigated the challenges presented by a 4IR environment and used that as a basis for primary research. The research design consisted of a survey instrument that was distributed at an organisation which identifies with the characteristics of a 4IR work environment. The researcher used statistical tools such as Spearman’s (1904) correlation coefficient and cross-tabulation, also known as two-way frequency tables which utilises small sample sizes. The researcher was able to identify and analyse the data. and finally, the researcher identified seven factors (determinants and antecedents) which 4IR employers might consider including in the EE strategies. Govender and Bussin (2020) emphasise the importance of identifying strategies that will enable South African companies to stay relevant and globally competitive by managing performance and EE.Thesis (MEng) -- Faculty of Engineering, the Built Environment, and Technology, School of Engineering, 202
Factors for successful digitalisation towards improved service delivery: a study of Buffalo City Metropolitan area
Full text linkThis study investigates the factors contributing to successful digitalisation for enhanced service delivery within Buffalo City Metropolitan Municipality (BCMM). As digital transformation becomes critical in modern governance, municipalities face the challenge of adopting digital tools to improve operational efficiency and service provision. Through a qualitative research approach, this study explores opportunities for digitalisation in BCMM, focusing on smart metering, smart city initiatives, and lessons learned from other municipalities. Data was collected through interviews with municipal employees, residents, as well as the analysis of municipal documents. The findings reveal that while BCMM has initiated efforts such as smart meters for utilities and a conceptual smart city plan, its digital transformation is hindered by inadequate implementation, lack of awareness, and financial constraints. The study underscores the importance of strategic planning, integration of digital technologies across departments, and effective change management in driving digitalisation. Recommendations include benchmarking against successful municipalities, addressing resident concerns about costs, and fostering collaboration between municipal leadership and information technology experts to ensure sustainable digital transformation. These insights provide a practical roadmap for enhancing service delivery through digital innovation in local government.Thesis (MBA) -- Faculty of Business and Economic Sciences, Business School, 202
Factors that influence the effective teaching of coding in South Africa: a case study on the Tangible Africa Initiative
Full text linkThe Fourth Industrial Revolution (4IR) has reshaped industries worldwide, creating a surge in demand for information and communication technology (ICT) skills, particularly in software development. However, South Africa faces significant challenges in embracing 4IR due to a shortage of digital skills, exacerbated by disparities in its education system and a persistent digital divide. This study investigates the factors affecting the effective teaching of coding through the Tangible Africa initiative, which uses mobile applications such as TANKS, RANGERS and BOATS to teach coding without requiring traditional computer infrastructure. These programmes present an innovative solution to introduce coding in underserved areas where access to computers and reliable internet are limited. Adopting a quantitative research approach, this study, distributed online via QuestionPro, received 41 responses from facilitators involved in the Tangible Africa initiative across various regions in South Africa. The research focused on identifying challenges faced by facilitators, their perceptions of the initiative and the impact on learners. Findings reveal that factors such as ICT infrastructure, facilitator skills and the learning environment significantly influence the success of coding education. Despite barriers like limited resources and inconsistent training, the study highlights the potential of mobile-based programmes to bridge the digital divide, providing foundational coding skills essential for South Africa’s participation in the global digital economy. This study contributes to the field by demonstrating the effectiveness of mobile-based coding education in resource-constrained settings. It emphasises strategies such as gamification to enhance learner engagement, comprehensive facilitator training to improve instructional quality and fostering collaborations between educational institutions and the private sector to expand access to digital tools. Recommendations include increased investment in ICT infrastructure in under-resourced schools and the development of targeted training programmes to equip facilitators with the necessary skills. By addressing these areas, the study offers a pathway to bridge the digital skills gap and better prepare South African learners for the demands of 4IR, promoting a more inclusive and competitive digital landscape.Thesis (MBA) -- Faculty of Business and Economic Sciences, Business School, 202
Offshore trusts: an analysis of the South African income tax advantages and risks
Full text linkThe use of offshore investment trusts by South African individuals gives rise to certain income tax advantages and risks. The primary objective of this study was to critically analyse the possible income tax advantages and risks associated with the use of an offshore investment trust by South African resident individuals. The research identified certain advantageous income tax planning opportunities stemming from the use of an offshore investment trust, namely the ability to defer the significant South African income tax event, possible loopholes presented by the present wording of certain income tax provisions pertaining to the vesting of accumulated trust capital in resident beneficiaries (albeit subject to interpretation) and structuring advantages, such as loop structures for reinvestment back into South Africa and possible avoidance of controlled foreign company provisions. The abovementioned tax planning opportunities have the potential to defer or reduce the possible South African income tax consequences that would otherwise be applicable. Notwithstanding the above, the research identified, analysed and described numerous instances of anti-avoidance provisions, potential adverse interpretational issues concerning certain provisions contained within the Income Tax Act relevant to South African beneficiaries receiving distributions from offshore trusts and practical challenges from an income tax perspective for resident beneficiaries of offshore trusts. The abovementioned observations present as significant income tax risks which should be evaluated, and their potential impact assessed, prior to the establishment of an offshore trust. The research explores the above income tax risks in more detail. The scope of the study is limited to the South African income tax implications applicable to an offshore investment trust, South African resident individual beneficiaries thereof and those resident individuals who may have capitalised or financed the offshore trust.Thesis (MCom) -- Faculty of Business and Economic Sciences, School of Accounting, 202
Reaction of palladium with silicon, cesium and zirconium in graphite
Full text linkThis study investigated how well silicon (Si) and zirconium (Zr) implanted graphite may be used to simulate the reactions of the fission product palladium (Pd) with Si and Zr in the pyrolytic carbon layer of irradiated tri-structural isotropic (TRISO) fuel particles. Hence, the study focused on how effective Si or Zr could capture and immobilize Pd in graphite, and secondly the possible effect of Si and Pd on the migration of Cs in graphite. The suitability of Si and Zr implanted graphite to simulate the behaviour of Si and Zr doped pyrolytic carbon (PyC) in a TRISO particle was investigated and the migration rates of Si and Zr towards and inside Pd were estimated. The stability of Si-Pd and Zr-Pd compounds formed at elevated temperatures was studied using energy dispersive X-ray spectroscopy (EDS). Finally it was attempted to determine whether Si or Zr would be more effective as a Pd getter (trap) in the PyC layer of TRISO particles. The results of the Si, Cs, and Zr implanted and annealed graphite are presented in the following order: (i)Ion ranges and concentration (at.%) of implanted ions at the projected range (ii)Graphite implanted with 275 keV Si ions at a fluence of 5 × 1015 ions cm-2 (iii)Graphite co-implanted with 137.5 keV Si ions at a fluence of 8.27 × 1015 ions cm-2and 137.5 keV Cs ions at a fluence of 1 × 1016 ions cm-2 (iv)Graphite implanted with 190 keV Zr ions at a fluence of 5 × 1015 ions cm-2. By co-implanting Si and Cs into graphite, the possible effect of Si on the migration of Cs in graphite in the vicinity of Pd could be investigated at different temperatures without any risk. The Stopping and Range of Ions in Matter (SRIM) program was used to calculate the projected ranges of energetic ions in graphite. Annular dark field (ADF) scanning transmission electron microscopy (STEM) and EDS analyses of ion implanted graphite samples were performed before and after annealing. The chemical affinity and formation energies of Pd, Pd2Si and Zr2Pd were used to explain the migration behaviours of Si, Pd and Zr observed.Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 202
Impacts of initial planting density and varying levels of mortality on Pinus patula pulpwood growth, yield, size inequality and profitability in southeastern Mpumalanga, South Africa
Full text linkThe South African forestry industry makes use of exotic monoculture plantations that are managed intensively to optimize growth, yield, uniformity and financial returns. This intensive management requires a sound understanding of how management and silviculture inputs impact forest growth, yield and profitability. Initial planting density is one of the most important forest management decisions influencing stand dynamics, especially in short-rotation, pulpwood stands which receive no thinnings. Within SA, most growth and yield (G&Y) research has been conducted on pine and eucalypt sawtimber stands, as well as on eucalypts grown for mining timber and pulpwood. Although many of the pine G&Y trials contained a range of planting densities (which would incorporate those used in both thinned and unthinned stands), limited data is available as to how initial planting density and varying levels of mortality impact growth, yield, size inequality and profitability in Pinus patula pulpwood stands. To address this, a Pinus patula trial was established in 2007 in southeastern Mpumalanga (South Africa) to test the impact of initial planting density and varying levels of mortality on pulpwood growth, uniformity, yield and profitability. The trial was measured annually until 14 years, 8 months and felled in 2022 due to the occurrence of Diplodia sapinea infection. The data was then projected to 17 years (rotation age) using the Forestry Scenario Analysis Tool. Three objectives, each dealing with a different aspect were set, the outcomes of which are highlighted below. The first objective dealt with the impact of seven different planting densities (620, 1 102, 1 293, 1 500, 1 722, 1 959, and 2 479 SPH) on individual tree and standlevel growth, size inequality and yield over 17 years. Although survival decreased with an increase in planting density (albeit only at p≤ 0.1) at rotation age, the final stocking was significant (p≤ 0.001) regardless of subsequent mortality experienced during the rotation period. The lowest stocked treatments had the largest quadratic mean tree diameter and volume tree-1, but with higher stand basal area and volume ha-1.The Gini coefficient indicated that DBH inequality was most prominent in the densely stocked treatments. In addition, the most densely stocked treatments had a higher slenderness coefficient, while the 1 293, 1 102 and 620 SPH treatments were the only ones that were stable when using the standard industry slenderness coefficient of 1.15 cm m-1. The optimum felling age, indicated by the current and mean annual increment was 16 years for the 1 102 and 620 SPH treatments, while it was 15 years for the rest of the treatments. Although the more densely stocked treatments (2 479 and 1 959 SPH)Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 202