4. Electronic Theses and Dissertations (ETDs) - Faculties submissions
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Item Exploring temporal changes in the malting barley seed microbiome with meta-omics to understand nitrogen content effects(University of the Witwatersrand, Johannesburg, 2024-10) Tshisekedi, Kalonji Abondance; De Maayer, Pieter; Botes, AngelaBarley (Hordeum vulgare L.) is a critical cereal crop, particularly in beer production, where it plays a significant role in the economy, especially in South Africa. Despite its importance, the barley seed microbiome, which affects seed storage and quality, is not well understood. This research addresses two key questions: (1) how microbial composition and function evolve during storage and (2) how the inherent nitrogen content of the grain affects these dynamics. Using metagenomic and metaproteomic approaches, eight barley samples from the Kadie cultivar, stored for various durations (harvest, three, six, and nine months) with high and low nitrogen content, were analysed. Metagenomic sequencing revealed a predominance of bacterial sequences and minimal fungal presence, with storage time having a greater impact on microbial diversity than nitrogen content. However, specific bacterial genera such as Erwinia, Pantoea, Pseudomonas, and Stenotrophomonas showed nitrogen-dependent prevalence. Metagenome-assembled genomes (MAGs) were reconstructed, representing 26 bacterial genera, with minimal shared orthologues, highlighting taxonomic diversity. Functional analysis identified key metabolic pathways and carbohydrate-active enzymes (CAZymes) essential for microbial adaptation during storage. Metaproteomic analysis further showed the active expression of proteins related to nutrient transport and stress response, indicating functional changes over storage time. Overall, this research enhances the understanding of the barley seed microbiome, providing valuable insights into storage practices that could improve brewing quality and agricultural sustainability.Item The Role of Psychology in Legal Education: Incorporating Cognitive Science into Legal Pedagogy(University of the Witwatersrand, Johannesburg, 2024) Starosta, Paulina Dagna; du Plessis, RiettePrevailing criticisms of legal education suggest that students enter clinical programmes ill equipped to solve problems and that they leave law school without learning the lawyering competencies of effective legal practitioners. This thesis is broadly premised on the idea that exposing law students to cognitive science and basic psychology would better equip them to achieve life-long learning and to acquire enduring practical lawyering skills. Psychology – the science of how people think and behave – has a great deal to teach us about the core competencies of lawyering. People who understand how others think, feel and behave, make better lawyers, decision makers and problem-solvers. Psychologists have conducted extensive research into psychological phenomena which are integral to effective lawyering. This research can be effectively incorporated into legal pedagogy, including how we teach law students to practice law. The proposal underpinning this research is the need for an undergraduate course on how psychology operates within the law, specifically designed to make students aware of how cognitive science and psychological phenomena affect and impact on the learning and practice of law. Developmental discourse regarding legal curricula entrenches the notion that law schools teach students how to think like lawyers but not how to be lawyers. The proposed response to this criticism is that metacognition – the awareness and understanding of one’s own thought processes – and the concomitant development of higher order thinking skills is key to the development of effective legal training, but this is presently absent in South African legal curricula. This thesis posits that experiential learning should begin before a student ever steps foot into a Law Clinic or a courtroom and that the reason why students leave law school unable to truly think like lawyers is because the notion is only truly introduced to them in their final year of law school, usually in the form of a clinical or experiential learning programme. The work contained herein is premised on the idea that legal educators ought to draw on the gains made by cognitive psychologists in understanding what happens when people learn and what neuroscience has to say about how people think and to introduce this to students at a relatively early point in their legal studies. The hypothesis underpinning this research is thus, that harnessing the science of psychology and allowing it to permeate legal pedagogy would be beneficial because the processes involved in both learning and lawyering are intricately linked to innate psychological processes and responses. Thus, the proposal is for an introductory course in basic legal psychology oriented at producing graduates who can think critically and solve problems pragmatically – graduates who are able to not only think like lawyers but also vi to act like lawyers. The research is significant as it explores the viability of such a course within the LLB curriculum at the University of the Witwatersrand and considers what such a course would look like in the South African context. An undergraduate course on psychology within the law would give students a sense of understanding themselves before they try to make sense of the actions and motivations of others (like clients, judges and opponents) when they enter their clinical programme. It is my contention that currently, legal education fails to adequately bridge the gap between law and practice because students are never taught to factor in the feelings, fears, concerns and motivations of themselves or others. A course, which exposes students to their own psychological motivations, as well as those of other players in the litigation arena, would give students the context of how to approach the acquisition of skills and the competencies required to practice law in a more pragmatic manner. Chapter 1 introduces the basic premise behind the research and orients the research focus. Chapter 2 explores both the theoretical and practical criticisms of traditional legal education locally and internationally. This chapter explores the need for the development of the South African LLB degree in the context of recommendations made by the Council for Higher Education (CHE). The chapter proposes the use of cognitive learning theory to maximise law school learning by drawing on research related to metacognition and the influence of learning styles. Chapter 3 introduces the importance of psychology within the law and orients the role of psychology in legal practice in the context of skills acquisition in undergraduate study. The chapter proceeds to isolate five indispensable legal skills required of law graduates to practice law and gives insight on how psychology impacts on the acquisition and use of those skills. This chapter advocates for the need for a stand-alone course on the study of basic psychology (including metacognitive learning) to improve lawyering skills. Chapter 4 focuses on the first part of course design, namely, the values, goals and outcomes of the proposed course on psychology within the law. This chapter engages with the values which underpin the course design process, the need to focus on law as being grounded in the humanities as opposed to being viewed as a science and the ultimate exorcism of the theory- practice divide. A proposal is made for the use of the unified learning model (ULM) in the development of the proposed course and lessons from experiential learning are used to set goals and outcomes for the syllabus. Lastly, the chapter focuses on the proposed placement of the intended course within the broader LLB curriculum. Chapter 5 focuses on the course methodology, course content and assessment of the proposed course. The chapter describes numerous teaching methodologies and their implications on the choice of course design model. Lessons on proposed course content from similar courses offered in the United States of vii America (USA) and Australia are used to construct a proposed syllabus, course outline and assessment plan for the course. Essentially, this chapter constructs a hypothetical pilot course for adaptation within the undergraduate LLB curriculum based on the goals, outcomes and placement referred to in chapter 4. Chapter 6 contains concluding remarks, reflective findings and proposals for the extension of this research.Item Towards the development and determination of trace impurities in battery grade nickel sulphate(University of the Witwatersrand, Johannesburg, 2024-10) Mabowa, Mothepane Happy; Tshilongo, James; Chimuka, LukeThis study introduces innovative research focused on developing and optimizing advanced extraction techniques for refining nickel hydroxide from secondary material solutions. This precursor to nickel sulfate is effectively purified through impurity removal and precise determination, enhancing the final product to battery grade standards. The research addresses the extraction of metal hydroxide from secondary sources such as spent batteries and industrial waste, promoting recycling and reducing environmental impact. By refining analytical methodologies and improving impurity control, this study advances the sustainable production of high quality nickel sulfate essential for advanced rechargeable batteries. The key challenge addressed in this study is the presence of impurities in secondary material solutions, which complicates the process of refining nickel hydroxide and hinders the production of high-purity nickel sulfate suitable for battery applications. Existing methods for recovering nickel from secondary materials are often inefficient, leading to high impurity levels, low recovery rates, and significant environmental impacts. Current methods such as solvent extraction and precipitation often fail to achieve the desired purity levels for nickel sulfate, necessary for use in high-performance battery manufacturing. Furthermore, these methods can be costly, resource-intensive, and environmentally damaging. Analytical methods used to measure impurities also have limitations. The complex and saturated matrix of battery-grade solutions challenges accurate impurity determination, often necessitating indirect methods such as difference analysis from nickel sulfate, which may not fully capture all impurity types or their concentrations. To resolve these issues the study focuses on optimizing advanced extraction techniques from these secondary sources. The research includes: (1) investigating the effectiveness of S-Curve precipitation by varying parameters such as pH levels, nickel concentration, precipitate dosage, temperature, impurity concentration, and solubility products; (2) evaluating solvent extraction for copper removal prior to nickel precipitation; (3) validating various analytical techniques (FAAS, EDXRF, ICP-OES) for trace element analysis; (4) examining lime precipitation for the removal of iron, manganese, and copper; and (5) characterizing β-nickel hydroxide (Ni(OH)₂) using scanning electron microscopy (SEM), X-ray diffraction (XRD) patterns, Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The research employed a combination of precipitation methods, solvent extraction, and advanced analytical techniques. The S-curve precipitation of nickel hydroxide was optimised by varying pH levels, nickel concentration, and temperature. The study also examined lime precipitation as a method for impurity removal and used solvent extraction for copper removal before nickel recovery. Various solvents with different ratios were utilized at room temperature for copper extraction, and the 1:5 ratio of 5,8-diethyl-7-hydroxydodecan-6-oxime (LIX 63-70) proved to be effective. Analytical tools like FAAS, EDXRF, and ICP-OES were employed to validate the concentration of trace impurities, and techniques such as SEM, FTIR, XRD, and XPS were used to characterize the crystalline structure and purity of β-Ni(OH)₂. The first part of the work entailed devising a technique to extract base metals, specifically nickel, from the waste stream resulting from the nickel sulphide-fire assay waste. This study explores the recovery of nickel (Ni) through a combination of solvent extraction and precipitation techniques. The main objective is to develop an efficient process for separating Ni from copper (Cu) and iron (Fe) impurities, thereby optimising metal recovery at varying pH, concentration with addition of calcium hydroxide at 60˚C and contributing to the circular economy. The approach involves using LIX 63-70 for solvent extraction, which effectively loads Cu into the organic phase and allows for Ni liberation into the aqueous phase. Characterization of the S-curve precipitation process was carried out using various analytical techniques. The precipitation of Ni(OH)₂ was optimised at pH 6.5, as evidenced by X-ray diffraction (XRD) patterns, Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The results show that Ni(OH)₂ precipitates in a crystalline β-phase, with XPS confirming the successful precipitation and minimal presence of Cu and Fe impurities at pH of 6.5 at 60˚C. Notably, the study also identifies the presence of Fe and Ca impurities at pH 2.5, as indicated by scanning electron microscopy (SEM), energy-dispersive X ray spectroscopy (EDX), and XRD analyses. The study addresses a critical research gap by providing a detailed assessment of the separation process for Ni from complex waste streams. It demonstrates the efficacy of 5,8-diethyl-7-hydroxydodecan-6-oxime (LIX 63-70) in selectively extracting Cu and reveals the influence of pH on the purity of Ni(OH)₂ precipitates. The process also involves significant lime consumption for neutralising the feed solution, with about 71% used to adjust the solution to pH 2.0, highlighting the importance of optimising reagent usage. The research presents a successful method for recovering Ni from fire assay waste in separating value-added metals from impurities. The findings contribute to advancements in metal recycling and repurposing, supporting the development of sustainable waste management practices and the promotion of a circular economy. Paper II evaluates the accuracy and reliability of elemental analysis in synthetic cathode liquor using Energy Dispersive X-ray Fluorescence (EDXRF) and Flame Atomic Absorption Spectroscopy (FAAS) with both factory default settings and after internal calibration and compares these results with those obtained from Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). The research aims to test the performance of EDXRF and FAAS for identifying and quantifying elements such as calcium (Ca), sodium (Na), cobalt (Co), iron (Fe), nickel (Ni), copper (Cu), arsenic (As), selenium (Se), antimony (Sb), and bismuth (Bi). The investigations into the impact of these parameters on the variations in absorbance for the targeted impurities guarantee satisfactory linearity and recovery. The recovery was quantified by comparing the concentration of elements in spiking samples and certified reference materials (CRMs) to known quantities, while the sensitivity of each method was assessed by the limits of detection (LOD). Linearity was assessed by constructing calibration curves at a variety of concentrations and calculating the coefficient of determination (R²) to guarantee precise results at varying concentration levels. Initial EDXRF results using default settings showed substantial inconsistencies, particularly with Ca, where measured values invariably showed 0 mg/L despite actual concentrations ranging from 0 to 0.15 mg/L, and Ni, where measured concentrations varied between 493,327 and 529,280 mg/L compared to the true value of 120,000 mg/L. After calibration, EDXRF displayed better accuracy for Co, Fe, and Cu but experienced limits with light elements like Se and Sb due to high LOD. FAAS demonstrated effective results for Co, Cu, Fe, and Mg but encountered limits, particularly in detecting low amounts of metals like Na. FAAS readings for Na demonstrated high variability with a standard deviation (SD) of 505.24 mg/L and a relative standard deviation (RSD) of 23.39%. Furthermore, differences in FAAS measurements for Ca, Fe, and Ni were seen, with fluctuations in standard deviation (SD) and relative standard deviation (RSD) suggesting a certain level of inconsistency. The ICP-OES results confirms the accuracy of FAAS by closely aligning with its measurements for elements such as Co and Ni. The precision of FAAS is further demonstrated by the low standard deviations (8.08 mg/L for Co and 4 mg/L for Ni) of ICP-OES results (e.g., Co: 990 mg/L, Ni: 126 mg/L). This validation underscores the dependability of FAAS to these components due to selection of FAAS for its cost-effectiveness and broad applicability in industrial analysis. Evaluation of numerous methods is crucial for a thorough evaluation of elemental analysis accuracy, as evidenced by the comparison with ICP-OES. In addition, it is crucial to distinguish between the discourse on analytical methods and recovery metrics, as recovery rates are more closely associated with preconcentration techniques than with the analytical methods themselves. This work aims to fill a significant research need by emphasising the need for internal calibration for EDXRF and the necessity of using several analytical methods in conjunction to obtain dependable results. It stresses the strengths and limits of each method, providing a complete approach to enhancing analytical accuracy in industrial applications. The study in Paper III investigates the characterisation and retrieval of β-Ni(OH)₂ from fire assay waste using chemical precipitation. Various analytical methods are used to confirm the successful synthesis and purity of the molecule. Nickel hydroxide (Ni(OH)₂) is a functionally diverse chemical with a broad spectrum of uses. A hexagonal crystalline structure of β-Ni(OH)₂ is confirmed by X-ray diffraction (XRD) analysis, therefore validating the successful precipitation procedure. Fourier-transform infrared spectroscopy (FTIR) spectra provide additional evidence for the presence of nickel hydroxide by displaying distinct peaks associated with υ(OH) and υ(NiO) bonds. The X-ray photoelectron spectroscopy (XPS) analysis reveals the significant Ni²⁺ oxidation peak, which confirms the successful precipitation at a pH of 6.5. Additionally, XPS analysis detects the presence of contaminants such as chlorine and calcium in the waste matrix. Scanning electron microscopy (SEM) shows layered granules with a predominantly transparent brucite analogue crystalline phase, typical of β-Ni(OH)₂. It also exposes rough textures and uneven aggregation, indicating increased oxide concentrations on the Ni surface. The presence of nickel (Ni) and oxygen (O), as well as calcium (Ca) impurities arising from the chemical precipitation process, is confirmed by energy-dispersive X-ray spectroscopy (EDX). An investigation of particle size distribution indicates an average particle size of 2.0 µm. The results of Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) indicate a reduction in Ni concentrations, with recorded values of 62.7 g/L in the pregnant leach solution, 0.8 g/L in the precursor solution, and 0.501 g/L in the solid precipitate (cake). The copper loading efficiency is measured to be 79%, accompanied by a nickel loss of 9.73% and a nickel recovery rate of around 90.27%. This effective separation process demonstrates a cost-efficient and environmentally responsible method for recycling nickel from acidic chloride media, underlining the broader potential for nickel reuse in industrial processes. This study conducts a comparative analysis of nickel oxide (NiO) that is derived from fire assay nickel sulphide (FA-NiS) and produced through chemical precipitation and sol-gel methods. The focus is on the structural, morphological, and sensing properties of the NiO. This research is significant in that it is the first to report on the application of NiO synthesised from waste materials for volatile organic compound (VOC) sensing. The primary goal is to clarify the distinctions in properties between NiO obtained through these methods and evaluate their suitability for environmental sensing applications. Nickel was initially extracted from the raffinate using 5,8-diethyl-7-hydroxydodecan-6-oxime. Subsequently, nickel hydroxide (Ni(OH)₂) was precipitated with lime (Ca(OH)₂) at pH levels of 2.5 and 6.5. The hydroxide was subsequently transformed into NiO through a thermal treatment process. The presence of nickel and oxygen at pH 6.5, as well as iron, nickel, and oxygen at pH 2.5, was verified through the use of scanning electron microscopy (SEM)-energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). In both the sol-gel and chemical precipitation procedures, the X-ray diffraction (XRD) analysis demonstrated a cubic crystal structure with high average crystal sizes of 39-41 nm. The sol-gel process resulted in homogenous spherical particles, as evidenced by SEM imaging, whereas chemical precipitation resulted in aggregated layered grains. It is important to note that NiO precipitated at pH 2.5 exhibited coalesced hexagonal particles with a substantial amount of nickel and iron. The transition from nickel hydroxide to nickel oxide is essential because NiO is highly effective for VOC sensing due to its semiconductor properties. The study highlights the importance of utilising NiO in the detection of volatile organic compounds (VOCs) and the impact of each synthesis method on the material's sensory capabilities. Using certified reference materials, analytical methodologies, such as inductively coupled plasma optical emission spectrometry (ICP-OES) and X-ray fluorescence (XRF), demonstrated high-purity NiO (approximately 75%) with a low relative standard deviation (RSD <0.05%) and 90% recovery. The CRM AMIS 56 and SARM 33 were analysed alongside the samples to ensure reliable results were reproducible. Even at the lowest concentration of 1.5 ppm, NiO derived from fire assay waste demonstrated unambiguous sensing responses at 25˚C and 150˚C, with recovery times of 80 and 120 seconds, respectively. The potential of NiO from fire assay waste as an intriguing candidate for VOC sensing applications under ambient conditions was indicated by the highest response (Rg/Ra = 1.198 for 45 ppm ethanol) observed at 150˚C. The findings in paper IV highlight the suitability of nickel oxide synthesized from different methods for environmental sensing applications, particularly in volatile organic compounds detection. In Paper V, the focus is on the removal and characterization of impurities from pregnant nickel solutions at various pH levels, with an emphasis on enhancing nickel recovery and sustainable resource management. Lime is used as a precipitation agent to target impurities such as iron, lead, tin, manganese, and copper. The study employs inductively coupled plasma optical emission spectrometry (ICP-OES) to quantify and characterize these impurities. The objectives include improving analytical approaches for detecting trace contaminants, evaluating ICP-OES reliability for quality control, and assessing precipitation efficiency across different pH levels. Results reveal successful Fe3+ precipitation within the pH range of 2.0-3, alongside efficient manganese and copper precipitation at pH 5.5-6 and 4-6, respectively, aligning with established behaviours. The findings emphasise the significance of pH control for optimizing impurity removal from pregnant nickel solution, offering insights for enhancing nickel recovery processes in industrial settings. ICP-OES, supported by standard solutions and certified reference materials (CRMs), demonstrated exceptional linearity with correlation coefficients above 0.9995. The method showed high sensitivity, with detection limits and recoveries of CRM samples consistently within 10%. The study found that precipitation efficiency varies significantly with pH. Nickel (Ni) exhibited reduced precipitation at pH 2.02, with substantial precipitation occurring only at pH 6.5. Manganese (Mn) began precipitating at pH 2, achieving a peak removal efficiency of 98% at pH 6. Copper (Cu) precipitation started at pH 4, with a maximum efficiency of 99.3% between pH 4 and 6. Iron (Fe³⁺) was efficiently removed at pH 2.0-3.0. Significant variations in contaminant concentrations were observed, influenced by pH and precipitation agents. Fe³⁺ was removed with 100% efficiency at pH 2.5, while Cu precipitation was highly effective (99.3%) between pH 4 and 6. The decrease in Ni concentration at pH 2.02 was attributed to interactions with other metals rather than direct Ni precipitation. SEM revealed the morphology of the precipitates, showing a cauliflower-like structure for Ni(OH)₂ at pH 6.5 and the EDX confirmed the elemental composition of the precipitates, including Fe, Cu, Ni, Sn, Si, Al, Cl, Ca, and hydroxyl groups (OH), highlighting the presence of impurities precipitated at pH 2.5. This research highlights the effectiveness of ICP OES and EDX in trace impurity analysis and provides insights into optimizing precipitation processes, contributing to better recycling strategies and quality control in nickel processing and battery-grade materials. The study found that β Ni(OH)₂ precipitated optimally at pH 6.5, with a recovery rate of approximately 90.27% and minimal copper (79% loading efficiency) and iron impurities. Lime precipitation effectively removed Fe³⁺ at pH 2.5 and Cu between pH 4 and 6, with high removal efficiencies. Analytical methods such as EDXRF and FAAS, when calibrated, provided accurate results for trace elements, though discrepancies were noted for certain elements. The advancements in extraction and purification techniques, coupled with improved analytical methods and the novel application of NiO in VOC sensing, contribute significantly to the field of nickel recovery and processing. This research supports sustainable recycling practices and enhances the practical utility of recovered nickel, advancing both industrial applications and waste management strategies. Overall, this thesis contributes to advancing the understanding of impurity removal processes in nickel recovery and underscores the importance of precise control and characterization techniques in industrial applications.Item Unveiling the biochemical pathway between Type 2 Diabetes Mellitus and early Alzheimer’s disease(University of the Witwatersrand, Johannesburg, 2024-08) Tooray, Shweta; van der Merwe, EloiseResearch related to Alzheimer's Disease (AD) remains a focal point in neurodegeneration studies. This is due to the severity of AD and the clear necessity for non-palliative treatment approaches, as underscored by the high prevalence of the disease. The combined formation of extracellular senile plaques and neurofibrillary tangles (NFTs) plays a crucial role in the development of the cognitive and behavioural symptoms observed in individuals with AD. Despite extensive research efforts, discovering a definitive cure for the disease remains a challenge. Therefore, it is imperative to explore new perspectives and identify the upstream molecular mechanisms that contribute to the onset of the disease. Metabolic disorders are widely recognized as a significant risk factor for AD. Specifically, the metabolic syndrome, Type 2 Diabetes Mellitus (T2DM), is connected to neurodegeneration by promoting the accumulation of neurotoxins, inducing neuronal stress, affecting synaptic communication, and leading to brain atrophy. Individuals with T2DM have an increased risk of developing dementia, with hyperglycaemia exacerbating the impact of AD by causing mitochondrial dysfunction and oxidative stress through reactive oxygen species (ROS) formation, which are also present in AD. Additionally, patients with T2DM exhibit shorter telomeres linked to cell death, which is an associated risk factor for developing AD. These key pathways involved in connecting T2DM and AD were explored in the current study to enhance the understanding of the early events that precede AD. Glucose uptake was measured and observed to decrease over time as a potentially protective response of the cell. Subsequently, mitochondrial activity, assessed using the Alamar blue assay, was found to be heightened as an initial protective mechanism of Aβ42. This was later overwhelmed by the elevated ROS detected through a Total ROS assay kit, induced by the hyperglycaemic state of T2DM. In turn causing the amount of Aβ42 to become toxic and leading to a decline in mitochondrial DNA (mtDNA) over time as measured through qPCR. Additionally, the increases in ROS induced by hyperglycaemia resulted in oxidative damage to telomeres. Simultaneously, Aβ42 physically hinders telomere-telomerase binding, leading to reduced telomerase activity and consequently, shorter telomeres. Furthermore, this study reveals, for the first time, that the novel glucose-lowering drug (GLD) caused an increase in Aβ42 production in the T2DM cell model, whilst effectively decreasing ROS production over a 24-hour period compared to the untreated cell model. The rise in Aβ42 levels caused by GLD could potentially be working to prevent the increase in hyperglycaemia-induced ROS through its metal chelating antioxidant properties by scavenging ROS, in the presence of oxidative stress associated with T2DM. These findings are indicative of an appealing function of GLD by reducing ROS and thereby impeding the progression towards AD. Hence making GLD an attractive therapeutic option for the treatment and/or prevention of AD.Item GIS-Based Location-Allocation Modelling of School Accessibility in the Bojanala Platinum District Municipality, South Africa(University of the Witwatersrand, Johannesburg, 2024-09) Molefe, Kebarileng Christinah; Atif, IqraSchool accessibility modelling performs a crucial part in guaranteeing that educational institutions are physically and practically reachable by every student, irrespective of their abilities, disabilities, or socioeconomic status. Neglecting school accessibility perpetuates inequality, reinforces negative stereotypes, and isolates affected students. Therefore, the principal goal of this research was to evaluate the distribution of schools across the Bojanala Platinum District Municipality, focusing on their accessibility to local communities. The study employed an integrated approach, combining geostatistical techniques, location-allocation modelling, and multicriteria decision analysis. By considering both quantitative data and spatial relationships, these methodologies contributed to robust decision-making and informed policy recommendations. The study utilized population data and school-related information sourced from the Department of Education and the HUMDATA websites, both dated to the year 2020. The study examined the distribution of schools in the Bojanala Platinum District Municipality. It was discovered that the schools were clustered, with a concentration in the Rustenburg local municipality, followed by Madibeng. However, a significant inequality in school access was evident. Secondary school students faced the greatest vulnerability, as most accessible schools primarily served primary students. To address this, potential school sites were proposed across the district. The study emphasizes the need for effective interventions by educational administrators and policymakers to eliminate this inequality. This study recommends the establishment of new schools in underserved regions, strategically enhance existing schools, and maximize school accessibility for all residents. Adequate school provision promotes equity, reduces travel burdens, and strengthens community bonds.Item Developing a Bayesian Network Model to Predict Students’ Performance Based on the Analysis of their Higher Education Trajectory(University of the Witwatersrand, Johannesburg, 2024-08) Ramaano, Thabo Victor; Jadhav, Ashwini; Ajoodha, RiteshThe Admission Point Score (APS) metric, utilised as a response to admit prospective students for an academic course, may appear effective in determining student success. In reality, almost 50% of students admitted to a science programme in a higher education institution failed to meet all the requirements necessary to complete the programme during the period of 2008 and 2015. This had a direct impact on the overall graduation throughput. Thus, the focus of this research was geared towards the adoption of a probabilistic graphical approach to advocate its mechanism as a viable alternative to the APS metric when determining student success trajectories at a higher education level. The purpose of this approach was to provide higher education institutions with a system to monitor students’ academic performance en-route to graduation from a probabilistic and graphical point of view. This research employed a probability distribution distance metric to ascertain how close the learned models were to the true model for varying sample sizes. The significance of these results addressed the need for knowledge discovery of dependencies that existed between the students’ module results in a higher education trajectory that spans three years.Item The effect of parental education on child and adult health in Zambia: A regression discontinuity analysis(University of the Witwatersrand, Johannesburg, 2024) Daka, Lincoln; Booysen, FrederikThis thesis expands upon and enhances existing research in the field of health economics. The thesis consists of three separate yet interrelated chapters that examine the effect of education on key demographic variables: child health, fertility and HIV/AIDS in Zambia, three key factors affecting the progress of development in Africa. The endogeneity problem is present in all of the three empirical papers examined. To circumvent this endogeneity problem and establish a credible causal effect, we explore the impact of Zambia’s 2002 Universal Free Primary Education (UFPE) policy which created an exogenous source of variation in education as a quasi – experiment. The three substantial empirical studies, employ the same econometric methodology, a Regression Discontinuity Design (RDD), whose appealing feature is local randomisation. This characteristic has distinguished the method from other evaluation methods in terms of estimating unbiased treatment effects. Another advantage of the fuzzy Regression Discontinuity design is that it can account for the endogeneity of the treatment variable. The utilisation of the fuzzy Regression Discontinuity design is a valuable contribution in all of the research. Furthermore, every chapter makes a unique contribution within its respective sector. We outline Zambia’s Universal Free Primary Education (UFPE) Policy and also present the Regression Discontinuity Design methodology framework. We find significant causal impacts of maternal education on child health measured by height-for-age, weight-for-height and Weight-for- age. The findings also indicate that maternal education is associated with a reduction in the prevalence of stunting and underweight and no effect wasting contrary to other research. We present evidence of the several mechanisms by which maternal education impacts child health. The results of our study indicate that a greater level of maternal education exerts a beneficial influence on child health through the postponement of marriage, the reduction in total fertility, and the delay in the age of first childbirth and sexual debut. Additionally, we have discovered indications of positive assortative mating. Furthermore, education empowers moms by facilitating their access to information via television and newspapers, equipping them with knowledge about the ovulation time, and helping them to make well-informed decisions regarding contraceptive techniques. Conventional wisdom posits that decreased fertility may indicate the presence of “superior quality” children and increased rates of survival for both mother and child. Can education serve as a catalyst for decreasing fertility rates in developing nations? We find that female education reduces iv | P a g e the number of children ever born. We present evidence of the reduction in total fertility as a result of female education. We also show that female schooling reduces the preferred number of children and increases the age at first birth. We find that female schooling affects fertility through age at first sex and marriage, literacy, assortative mating and the knowledge effect. There is no evidence to suggest that female schooling has a major impact labour market participation. We present evidence of the heterogeneous impacts of a mother’s education based on “poor versus wealthy” criterion, whether rural/urban status, region and religion. We also present evidence of the effect of female education on the HIV seroprevalence status, number of sexual partners and knowledge of HIV transmission mechanisms. We show that female education lowers HIV seroprevalence status, decreases the number of sexual partners and increases HIV knowledge. Our research suggests that educated women are more likely to have a deep and detailed understanding of HIV. Lastly, we present evidence of the heterogeneous effects of female education by household status on HIV related outcomes.Item A review of the right to basic education, the 2020 Covid-19 related schools' shutdown, and the courts in South Africa(University of the Witwatersrand, Johannesburg, 2024) Booi, Ntombizinhle PrincessOwing to COVID-19, the South African government ordered the closure of educational facilities in the country to try and curtail the spread of the virus. At the time, no one knew the extent to which the virus had spread, its potency for the South African public, how it impacted on children and what actions the government could take, besides locking down the country. Both the government and the public were facing a pandemic of this kind for the first time. However, the closure of schools placed the educational rights of learners under a spotlight, as under the Constitution of the Republic of South Africa, 1996, basic education is a right. The closure of the schools had many consequences for the right to basic education, including that education delivery, as it was then known, had to be changed. Yet, it is reasonable to assume that many schools were ill equipped for the sudden change which could not have been foreseen. To this end, there had to be a way forward for schools, and online learning became a viable avenue for ensuring that education did not come to a standstill. Yet again, it is reasonable to assume that many schools would not have had the capacity to transition to, let alone facilitate and maintain, online learning. A preliminary conclusion then would be that COVID-19 had a direct impact on the right to education. This is only the start, however, because the next line of inquiry would be whether the decision of the state to close educational facilities through the lockdowns was reasonable, and consequently justified considering the limitation it brought to the right to education. This report concludes by examining two cases that addressed these questions.Item Low-temperature electronic transport of metal doped carbon nanotube molecular hybrids and Nitrogen-doped nanocrystalline diamond(University of the Witwatersrand, Johannesburg, 2024-08) Sodisetti, Venkateswara Rao; Bhattacharyya, SomnathThis thesis explores the magnetism and spin-related properties in carbon-based molecular hybrid materials, with a focus on expanding our understanding of low-dimensional carbon structures and their potential electronic applications. The investigation spans from one-dimensional systems, such as carbon nanotubes (CNTs) functionalized with single-molecule magnets (SMMs), to three-dimensional systems like nitrogen-doped ultra nanocrystalline diamond (UNCD). In these carbon structures, electronic transport is intricately tied to microstructural features, such as grain boundaries and impurity clusters, which hold significant potential for the development of all-carbon electronic devices. The research begins with a detailed examination of the chemical functionalization of multi-walled carbon nanotubes (MWCNTs) through controlled acid treatment to achieve precise metal doping. Using Raman spectroscopy and complementary techniques like ICP-MS and ToF-SIMS, we successfully demonstrate how functionalization levels influence the magnetic properties of CNT hybrids loaded with magnetic metals from the lanthanide series (Gd, Tb, Dy). The study reveals that low percentages of metal doping (0.5% to 1.0%) preserve the magnetic bistability of SMMs post-grafting, while higher doping levels lead to complex magnetic behaviors including super paramagnetism, quasi-ferromagnetism, and potential Kondo lattice behavior inCNT-heavy metal systems. We also explore the spin-phonon coupling in Gd-filled double-walled CNTs, where the onset of superparamagnetic properties at low temperatures is coupled with phonon mode stiffening observed via Raman spectroscopy. This enhanced coupling offers promising pathways for developing efficient molecular qubits through the modulation of spin-phonon interactions in one-dimensional systems. The second part of the thesis investigates into the microwave plasma-assisted chemical vapor deposition (MWCVD) growth of nitrogen-doped nanocrystalline diamond (NCD) thin films on different substrates. By pioneering upgrades to the MWCVD system, I was able to achieve reliable growth of high-quality nanocrystalline diamond thin films. Notably, I observed a novel nanostructure, termed Diaphite-a previously unreported feature, in these NCD films, consisting of nanodiamond grains coherently linked with graphene-like rings. This structure, along with the non-equilibrium growth conditions induced by nitrogen doping and secondary nucleation, presents unique polymorphic features in artificially grown diamonds. Detailed low-temperature transport measurements on four different samples—ranging from 7.5% to 20% nitrogen doping—uncovered complex transport phenomena such as 3D weak localization (WL), variable-range hopping (VRH), and unusual magnetoresistance (MR) behavior. In particular, the 7.5% N2-doped UNCD film on quartz exhibited 3D weak localization (WL) at low fields and anti-weak localization (AWL) at higher fields, with distinct magnetoresistance characteristics depending on the direction of the applied magnetic field. The 20% N2-doped films on both quartz and silicon showed more metallic-like behavior, with magneto-resistance characterized by a B1/2 dependence at low temperatures, suggesting an intricate relationship between doping level, microstructure, and electron transport. These findings significantly expand our understanding of the role that microstructural and chemical modifications play in determining the electronic and magnetic properties of carbon-based materials. This work provides a foundational platform for future research into carbon electronics, offering potential breakthroughs in spintronics, molecular transistors, quantum computing, and other advanced electronic applications.Item An examination of the legal framework for the governace of public universities in South Africa: The case of the Vaal University of Technology(University of the Witwatersrand, Johannesburg, 2024) Mahlako, Neo; Moyo, Khulekani