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Blueprint to Success Project Managers Perspectives onKey Factors Influencing Construction DocumentQuality in South Africa
No full textTypologies of South African smallscale farmers and their risk perceptions an unsupervised machine learning approach
No full textBrief Report HIV Drug Resistance Assessment among Women Who Seroconverted during the MTN025HOPE OpenLabel Extension Dapivirine Vaginal Ring Trial
No full textNumerical simulation of hydromagnetic flow and heat transfer of hybrid nanofluid over a rotating disk in a porous medium with slip conditions and hall current A buongiorno model approach
No full textAn Evaluation of the Relationship between Banks’ Regulatory Capital Adequacy Ratios and Profitability in the South African Banking Sector
No full textA research report submitted in fulfillment of the requirements for the Master of Commerce in Accounting, in the Faculty of Commerce Law and Management, School of Accountancy, University of the Witwatersrand, Johannesburg, 2025Background and Purpose: Banks are required to hold minimum capital amounts due to in- country regulation, which reflects the ability of the Bank to absorb unexpected losses and demonstrate resilience. This is driven by a function of risk-weighted assets and the Bank’s risk profile and appetite. Method: A quantitative research approach, utilising descriptive statistics and panel regression analysis was run on data over a twenty-year period (2002 – 2022), for 14 locally controlled Banks in South Africa. In addition to the afore-mentioned evaluation, the following relationships with profitability were also assessed: size, liquidity, management efficiency, implicit costs, cost efficiency, inflation and business cycle. Results: The analysis revealed a statistically significant positive relationships between capital adequacy ratios and profitability in South Africa; specifically, a statistically significant positive relationship between Tier 1 and Total Regulatory Capital ratios with ROA. Implications: The significant positive relationship mentioned above is attributed to strong resilience in the South Africa Banking sector, with high capital buffers over regulatory minimums and the ability to earn revenue during uncertain times. Continued oversight by Regulators on capital adequacy and macroeconomic indicators and risks is encouraged and Bank management is urged to continue to maintain healthy capital ratios and metrics, and effectively stress test and manage risks. Significance: This study contributes to the limited research on capital holdings and profitability of South African banks. The insights on capital holdings make a practical contribution to decision-making by bank management, investors and regulators regard capital holdings.MM202
Immunogenicity and seroefficacy of pneumococcal conjugate vaccines a systematic review and network metaanalysis
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Comprehensive contributions of the informal sectors in Solid waste management Systems: A case study of Central Johannesburg
No full textA research report submitted in partial fulfilment of the requirements for the degree of Master of Science in Environmental Science, to the Faculty of Science, School of Geography, Archaeology and Environmental Studies, University of the Witwatersrand, Johannesburg, 2025The informal waste management sector has become one of the most key components of solid waste management and has been part of society and the economy for three decades. Waste picker activities are within the lower spectrum of the waste management value chain. However, their challenges in functioning as waste pickers are misunderstood, given the rise in the waste within areas in Central Johannesburg. Waste pickers are paramount in the effective diversion of solid waste by steering and processing waste, further creating resilient systems in urban environments, and ensuring recycling practices. The study was completed to comprehensively understand the current contributions of the informal waste collectors within Central Johannesburg. The study area of Central Johannesburg, particularly Mayfair and Braamfontein, was selected as these two areas exhibit over population and urbanization coupled with residential and business-related activity. With these factors, Central Johannesburg has a high waste output. The study had four main objectives being the identification of the challenges the informal waste collectors in Central Johannesburg experience, the identification of the effectiveness of waste picker contributions from a citizen perspective, the examination of existing policy documents for solid waste management in Johannesburg as well as the identification of the best theoretical framework for the inclusion of waste pickers into formal solid waste management strategies in Johannesburg. The research used qualitative methodology with aspects of quantitative methodology. Using snowballing and purposive methods, twenty-five (25) waste pickers were surveyed along with twenty-two (22) citizens, four (4) informal waste pickers NGOs and NPOs and two (2) local authoritative figures. Semi-structured interviews were conducted with the relevant individuals, based on ethical grounds. A total of sixty (60) published data such as journals and news articles were analyzed to substantiate the objectives of the study. Furthermore, four (4) solid waste management policy documents from a national, provincial, and local perspective were analyzed. The research identified that waste pickers along with informal waste NGOs and NPOs, have challenges with coordination such as effective trolleys, being accepted by society and the amount of money they earn from their operations. Citizens had stated that they do have their recyclables collected by waste pickers on a weekly basis and have identified that waste pickers do play a role in waste management within Central Johannesburg, and further aid recycling efforts within the area. However, local authorities have stated that there is a need for waste picker involvement in decision-making and policy formulation. Solid waste management policy documents enforce effective waste management strategies for citizens and the city however there are gaps regarding waste picker integration into strategies, as waste management is regulated. The Inclusive Governance Framework is the most effective theoretical framework as it involves all individuals in decision-making, including marginalized groups. The study revealed the various dynamics among citizens, and waste pickers, and local authorities. There is a need for awareness programs for waste management education for citizens. Local authorities within Central Johannesburg identify with the waste picker operations however have also identified challenges such as poor relationships between them and waste pickers. Solid waste management policy documents are integrated however do not cater to waste picker activity more effectively and the Inclusive Governance Framework would allow for all stakeholders, including waste pickers, to deliberate in policy formulation and decision-making, providing them with equity and justice.MMM202
The extraction and recovery of rare earth elements, aluminium, titanium, and iron from South African coal fly ash
No full textA research report submitted in fulfillment of the requirements for the Doctor of Philosophy, in the Faculty of Engineering and the Built Environment, School of Chemical and Metallurgical Engineering, University of the Witwatersrand, Johannesburg, 2025Coal fly ash (CFA) is a waste material with the potential for high-value and high-volume utilisation in wastewater treatment and alumina production. The sinter-H2SO4 leach process can extract over 80 wt.% of aluminium, which can be commercially processed to generate smelter-grade Al2O3. However, due to the high costs involved in the pre-treatment and downstream purification steps, the process has proved neither feasible nor sustainable. This study reports on a holistic approach to adding value in alumina processing by extracting aluminium (Al), rare earth elements (REEs), titanium (Ti), and iron (Fe) as saleable products. The overall aim is to produce a rare-earth concentrate, smelter-grade alumina, high-purity titanium dioxide, and iron-based coagulants. The potential application of the generated secondary solid residue as an adsorbent for wastewater treatment is also evaluated. In the first experimental stage, CFA was characterised for its composition. XRD analysis revealed an amorphous component with crystalline mullite, quartz, and magnetite/haematite. SEM-EDS and TIMA analyses showed that Al-Si-rich grains are the predominant phase, with discrete REE-bearing grains (phosphates and silicates) and Fe-oxide (magnetite/haematite) grains. Traces of REEs, Ti, Ca, Si, and Fe were also found in the Al-Si-rich grains. Discrete Fe-oxide grains were further recovered using dry magnetic separation to reduce downstream purification costs. The results showed that up to 65.9% Fe-oxides could be recovered at 1.05 T (magnetic field strength). However, the magnetic fraction (CFA-MF) also contained mullite and quartz impurities. The non-magnetic fraction (non-MF) was further processed for the extraction of the selected REEs (Sc, Y, La, Ce, and Nd), Al, Fe, and Ti. In the preliminary leaching tests, the effects of leaching parameters were investigated using direct H2SO4 leach and sinter-H2SO4 leach processes. The former resulted in poor metal extraction due to the phase composition of CFA, while the latter showed a much higher extraction efficiency. In the sinter-H2SO4 leach process, a maximum of 72% Al, 63% Fe, and 40% Ti were extracted in 6 M H2SO4 by leaching at 70°C in a 1:4 S/L ratio for 10 hours. Under the same experimental conditions, less than 20% of the selected REEs were extracted, except for Sc which had 35% extraction. Further investigation was conducted using the sinter-HCl leach process, and the extraction efficiency was significantly improved, with over 50% REEs recovered in 4 M HCl by leaching for 6 hours at 70°C. The lower extraction iii efficiency of REEs in the sinter-H2SO4 leach process was ascribed to calcium sulphate precipitation and the complex phase composition. Nonetheless, the sinter-H2SO4 leach process was optimised using a Design of Experiments (DOE) for alumina production. Consequently, a CFA leach liquor and a solid residue (sintered CFA residue) were generated for further processing. The CFA leach liquor was concentrated with Al(III), Fe(II/III), and Ti(IV). It was processed by integrating solvent extraction (SX), crystallisation, and oxidation-precipitation processes. All Fe(III) in solution was first reduced to Fe(II), and Ti(IV) was selectively extracted using Primene JM-T/Shellsol D70, followed by stripping in NH4OH and calcination to produce TiO2. The synthesised TiO2 showed lower purity (95.03 wt.%) and BET surface area (10.05 m2/g) for application as a photocatalyst in wastewater treatment. However, it was classified as a type II pigment grade. Aluminium in the raffinate was directly crystallised and calcined to produce smelter-grade Al2O3. The remaining Fe(II)-rich solution was processed at pH 5.0, using an oxidation-precipitation process. Due to the gelatinous Fe(III) precipitate, which was difficult to filter, the recovered CFA-MF was recycled as seeding material to improve the precipitation process. Seeding significantly improved the filtration process for all concentration levels (Cs = 0.5, 1.0, and 2.0). The seeded Fe(III) precipitate at Cs = 1.0 was further used to produce polyferric sulphate (PFS) coagulants by dissolution in dilute sulphuric acid. The generated CFA-PFS was mainly concentrated with Fe(III) and contained minor amounts of Al(III), Mg(II), Mn(II), and Ca(II). The synthesised CFA-PFS coagulant was tested on brewery wastewater and found compatible with commercial PFS. Throughout the purification processes, REEs which were dissolved in the sinter-H2SO4 leach process, mostly remained in solution. The sintered CFA solid residue (CFA-SR) was characterised as a silica and calcium component with significant concentrations of REEs. Phase composition analysis revealed an amorphous material with a Si-Ca-S-rich phase and a Si-rich phase. Traces of Al, Fe, Ti, and REEs were mostly distributed in the Si-Ca-S-rich phase. To minimise the formation of silica gel, the dry digestion-water leach process was carried out in a sulphates and chloride system for REE extraction. The obtained results indicated that the solubility of calcium sulphates and the complex phase composition might be limiting factors for efficient REE extraction. Nevertheless, an REE concentrate was generated with low purity. As a result, the REE- concentrated solution was set as the final product. Overall, combining the sinter-H2SO4 leach iv process with the dry digestion-water leach process was considered a promising alternative for concentrating and selectively extracting REEs from CFA. A CFA secondary solid residue (CFA-SSR) was generated after the two-step leaching process for disposal. The material was characterised for potential recycling in wastewater treatment as an adsorbent. Characterisation showed an amorphous and crystalline component with mesopores measuring 11.7 nm. The average particle size was 44.76 μm, while the SBET was 29.236 m2/g (surface area). Batch tests showed that CFA-SSR has the capacity to adsorb heavy metals (i.e. Ni, Zn, and Fe) in acid mine drainage (AMD). The overall findings indicated that the adsorption capacity could be enhanced by functionalising CFA-SSR to improve selectivity and surface properties. A process flowsheet was designed for the proposed CFA processing using magnetic separation, a two-step leaching process, and an integrated purification process. The economic evaluation showed that more than one value-added recovery could be an alternative to generate revenue and offset some of the operational costs in alumina processing from CFA.DSI/NRFMM202
