Faculty of Science (ETDs)

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A study of the second-order dynamical systems for variational inequalities
(University of the Witwatersrand, Johannesburg, 2025-05) Ranoto, Tumelo; Izuchukwu, Chinedu
The purpose of this paper is to study the variational inequality problem through a second order dynamical system. The dynamical system is a second-order dynamical system that involves the asymptotic vanishing of damping and Hessian-damping terms. Our approach primarily uses the asymptotic dynamics of the inertial system and the geometric characteristics of the damping factors. The asymptotic vanishing damping is directly linked to the method of the Nesterov accelerated gradient. The geometry of the Hessian damping term is in this form d dt(y(t)−w(t)), where y(t) is the generated trajectories by our proposed dynamical system, w(t) = PC(y(t)−Qy(t)) and Q is our operator which is strongly monotone. The Hessian term assists with the neutralisation of the oscillation. This combination forms a damping force that assists with controlling the convergence speed of dynamical systems, stabilizing the system, and mostly ensuring we have a controlled velocity over time. As a main result, we establish the existence and uniqueness of the generated trajectories using the Cauchy-Lipschitz theorem. We give two numerical non-Hilbert examples. We construct a Lyapunov function to achieve weak convergence, assuming that the underlying operator is Lipschitz continuous and monotone. By considering the strong monotonicity of the operator, we establish exponential convergence. Furthermore, we given two numerical examples to show the applicability of our results. Finally, we conduct numerical experiments to show the performance of our dynamical system. The results presented in this paper build upon and significantly enhance recent findings in the existing literature.
Method development for the quantification of rare earth elements in South African monazite by various spectroscopic techniques
(University of the Witwatersrand, Johannesburg, 2025-03) Rangata, Mmantheka Patricia; Tshilongo, James; Mkhohlakali, Andile; Chimuka, Luke
The rare earth elements are critical, and their various applications include electronics, the defence sector, manufacturing, renewable energy, technology and the medical sciences. The increasing demand for these critical elements will strain the existing supply chain. There is a major concern that any disruption to the supply chain will negatively impact innovation. Countries worldwide are seeking to secure new reserves, find the material substitutes, and boost the research in recycling electronics that have reached the end of life. Monazite contains critical rare-earth-elements responsible for green energy transition. The bottleneck associated with analysing rare-earth elements in monazite is its refractory nature and associated heavy minerals that do not decompose completely in the sulphuric acid fuming procedure. Furthermore, rare-earth elements have been successfully measured in geological materials employing the sensitive inductively coupled plasma mass spectrometry techniques. Nevertheless, it suffers from a low tolerance of total dissolved solids in matrices such as monazite. While, inductively coupled plasma optical emission spectroscopy suffers from poor sensitivity and matrix removal is often required for accurate rare-earth elements determinations. Extensive research has been conducted on sensitive procedures and efficient sample preparation for trace elements determinations including rare-earth elements. This study aims to develop a method for direct determination of rare-earth elements in monazite. The monazite ore samples were collected from the extractive metallurgy within Mintek for method development for quantification of REEs. Three preparation methods for sample digestion techniques were evaluated. The methods involved the flux fusion method using the lithium metaborate and sodium peroxide respectively and the multi acids digestion with hotplate as the source of heat followed by rare earth elements quantification using both the inductively coupled plasma mass spectrometry and inductively coupled plasma optical emission spectroscopy. Moreover, the complete sample dissolution was achieved with the flux fusion method while the partial sample dissolution was observed via multiple (repetitive) treatment steps by multi acids digestion method. The total dissolved solids were mitigated, and the matrix effect was eliminated when glass beads were treated (dissolved) in a mixture containing nitric and hydrofluoric acids. The analyte spectrum was often completely obscured by wing overlap and direct overlap of emission lines from interfering elements during-inductively coupled plasma optical emission spectroscopy analysis. In addition, the recoveries for some rare earth elements were suppressed with enhanced spikes for rare earth elements concentration were observed from inductively coupled plasma optical emission analysis particularly from the solution samples digested in alkaline fusion. The inductively coupled plasma optical emission spectroscopy results for the rare earth elements suggest that the sample matrix significantly affects the sensitivity. The method’s validity was tested using a monazite ore-certified reference material. In contrast to the optical emission spectroscopy, the accurate analysis of rare earths from all the digested samples was obtained using the inductively coupled plasma mass spectrometry. The results of the rare earth elements obtained for all digested samples analysed using the mass spectrometry strongly agree with the certified values. The excellent accuracy of the method was realised with the rare earth elements data obtained from quality control samples, and recoveries yield within the range of 90-110%, and the relative standard deviation of 0.2-5.4%. The selectivity and sensitivity of the method were realised with individual rare earths accurately measured in the presence of other interfering elements, as indicated by lower detection of limit ~ (0.0004-0.016 ppm) and limit of quantification ~ (0.0001-0.0290 ppmn). Calibration curve linearity for individual rare earth elements is demonstrated by the correlation coefficient in the range of 0.99 to 1.0. Moreover, multi fusion methods followed by mass spectrometry are futuristic analytical approaches for determining rare earth elements in monazite associated minerals and they can be used interchangeably. In South African context, South Africa should prioritise the development of Rare Earth Elements (REE) extraction and recycling technologies in order to maximise yield, purity, and environmental sustainability, notably through enhanced procedures for monazite-rich deposits. Investing in a circular economy paradigm, such as boosting REE recovery from electronic trash, can minimise dependency on virgin resources and help to create a more sustainable future. To further help the country's green energy transition, the government should fund research into REE-based technologies critical to renewable energy systems such as wind turbines, solar panels, and electric cars. Furthermore, developing regulatory frameworks that ensure responsible mining techniques and monitor the entire REE supply chain will assist to mitigate environmental and social consequences. Additionally, South Africa can enhance its role in the global REE market by collaborating with international partners, leveraging external expertise, and promoting sustainable technologies, thereby contributing to a low-carbon economy.
Causal Inference in Water Distribution Networks to Quantify the Effects of Network Damage
(University of the Witwatersrand, Johannesburg, 2025-05) Rammutloa, Katlego Lucas; Mulaudzi, Rudzani; Ajoodha, Ritesh
Water Distribution Networks (WDNs) are engineered systems of interconnected pipes, pumps, and reservoirs that deliver potable water from treatment plants to consumers. These networks are critical to public health but are highly vulnerable to structural damage (e.g., leaks, pipe corrosion), which disrupts water flow and complicates impact prediction. Current methods for assessing damage—such as hydraulic simulations and machine learning—rely on statistical correlations or optimisation, failing to model causal relationships. This limits their ability to predict cascading effects or guide repairs under uncertainty. This study addresses these limitations by applying a causal inference framework for analysing WDNs. The framework leverages graphical causal models to represent the network’s structure and quantifies the impact of damage on water flow predictions. Using Average Treatment Effect (ATE) and Mean Squared Error (MSE) metrics, we analyse how structural damage affects prediction accuracy across different network regions. The framework focuses on three critical areas: source nodes (reservoirs and entry points), mid-network nodes (junction points and main distribution pipes), and consumer nodes (end-user connection points). Experiments on a simulated WDN reveal that damage affecting 40% or more of the network significantly compromises predictive accuracy. Mid-network and consumer nodes prove particularly vulnerable, with damage to these locations causing the greatest disruption to flow predictions. In contrast, source nodes demonstrate greater resilience due to built-in redundancies. Additionally, the study finds that treatment locations closer to outcome variables maintain predictive accuracy longer under damage conditions. By integrating causal inference into WDN analysis, this research provides network operators with a robust methodology for evaluating damage impacts and offers actionable insights for improving network resilience. The findings contribute to both infrastructure management practices and the broader application of causal inference to complex systems analysis.
Paternity, floral morphology and pollen viability analyses of African Baobab (Adansonia digitata L.) populations in South Africa
(University of the Witwatersrand, Johannesburg, 2023) Hall, Timothy; Glennon, K.L.; Goodman-Cron, G.V.; Venter, S.M.; Witkowski, E.T.F.
The African baobab (Adansonia digitata L.) is a valuable flagship, cultural and socio-economic species for communities across Africa. Not only is the baobab an important medicinal plant, but products such as seed oils and fruit pulp are sold to supplement rural community income. Baobab trees produce hermaphroditic flowers, but fruit numbers vary between individuals, with some trees producing many fruit (50 –200) every season, termed producers, and other trees producing little to no fruit every season (< 5), poor producers. This difference is not due to environmental conditions such as rainfall, soil conditions or land use type as tree types occur in the same environment, sometimes only meters apart. The aim of this study was to evaluate how floral reproductive traits and the movement of pollinators between A. digitata producer and poor producer trees may affect the paternity of seed sets from producer trees. I measured seven floral traits of producers and poor producers to assess floral differences using one-way ANOVA between the tree types across three populations in the Vhembe region of South Africa. Floral traits included flower diameter, stamen ball diameter, filament length, anther length, stigma surface diameter, style length from stamen ball emergence and peduncle length. Producers had longer styles emerging from the stamen balls and longer peduncles, whereas poor producers had larger stamen balls, longer filaments, and larger anthers. There were no differences in flower diameter and stigma surface diameter between producer and poor producer trees. Similarly, canopy volume, width, and stem diameter revealed no difference between tree types. Additionally, I evaluated differences in pollen viability between producer and poor producer trees using Alexander’s stain. Although both tree types possess viable pollen, poor producers had nearly 50% higher percentage viability compared to producers. There appears to be some level of functional dioecy across baobab individuals as we found that trees either allocate resources predominantly to either male or female floral structures. Assessing the movement of alleles as a measure of pollen movement between trees may aid in our understanding of how this functional dioecy is influencing allele movement within the population. Eleven microsatellite loci were amplified to assess the paternity of 117 offspring from 13 ‘maternal’ fruit-producing trees across three A. digitata subpopulations in Vhembe, South Africa. v The six nearest potentially paternal trees to each maternal tree were genotyped to test whether they were pollen donors. Parentage analyses conducted using POLYGENE revealed that offspring of maternal trees had alleles from multiple genotyped pollen donor trees outside of their six nearest trees with selected paternal trees contributing pollen to multiple maternal trees. Analyses suggested that pollen dispersed an average of 300 m within subpopulations, but also repeatedly dispersed distances over 40 km between subpopulations. The duration of pollen viability was determined through pollen tube germination trials and aids in our understanding of how long pollen remains viable for in the environment. Pollen grains that were 24, 48 and 72 hours old were deposited on receptive stigmas and allowed to germinate overnight. Scanning electron microscopy was used to confirm pollen tube growth for the three ages of pollen; it indicated that the pollen remains viable for at least 72 hours as it successfully germinated on stigmatic surfaces across these three treatments. This indicates that pollen present in the environment, especially on the surface of pollinators (e.g., moths, bats, or beetles) has the potential to pollinate flowers when up to 72 hours old, although pollen that is older than 72 hours may still be viable, which requires further investigation. The degree of functional dioecy in individual baobab trees, proportion of viable pollen, and extensive potential range of pollen dispersal, all contribute to our knowledge of A. digitata fruit production. Understanding baobab fruiting may aid in future conservation and regeneration strategies and would improve agroforestry security of the species.
Antimicrobial activity of silver and copper nanoparticles incorporated with biodegradable polymeric scaffolds for wound healing application
(University of the Witwatersrand, Johannesburg, 2022) Shumbula, Ndivhuwo Prince; Moloto, Nosipho
There has been a significant increase in the prevalence of chronic diseases such as diabetes and cancer which cause wounds like diabetic foot ulcers and pressure ulcers. This usually causes infection(s), leading to the amputation of limbs or even death. Chronic wounds do not follow the typical stages of wound healing and thus either take a very long time to heal or do not heal at all. Therefore, the need for developing advanced and novel wound treatment products that offer infection control and sharp debridement is vital. To combat this issue, this project focussed on fabricating bioactive nanomaterials to design an advanced wound dressing in the form of 3D scaffolds. The scaffolds were made of nanocomposites containing biocompatible and biodegradable polymers decorated with antimicrobial active Cu and Ag NPs. Prior to designing the scaffolds, pristine Ag and Cu NPs were fabricated and their antimicrobial activity and cytotoxicity were tested. The antimicrobial activity of these NPs was tested against E. coli and S. aureus bacterial strains, while their cytotoxicity was evaluated using baby hamster kidney fibroblasts (BHK-21) cells. Ag NPs with various sizes and spherical shapes were synthesized using dopamine (DA) as a reducing agent. Ag NPs with the smallest diameter exhibited the most antimicrobial activity compared to those with big diameters. The cytotoxicity of Ag NPs was very low, with cell viability of over 70% between 2 μg/mL and 32 μg/mL. At concentrations above 32 μg/mL, a decrease in cell viability was observed, indicating increasing toxicity, especially for small NPs. Cu-based NPs were also synthesized using hydrazine and DA as reducing and capping agents, respectively. Pure metallic Cu, Cu 2 O and the mixture of Cu and Cu 2 O (Cu/Cu2 O) NPs were separately prepared. Cu and Cu2 O NPs exhibited promising antimicrobial activity against E. coli and S. aureus. An improved antimicrobial activity was observed for Cu/Cu2 O NPs, compared to the Cu and Cu2O NPs, and this was attributed to the synergistic effect. The cytotoxicity of Cu2 O NPs was higher compared to that of Cu and Cu/Cu 2 O NPs. The antimicrobial activity and cytotoxicity of both Ag and Cu NPs incorporated with polydopamine (PDA) were also studied. Cu and Ag NPs were either embedded within the matrix of PDA (Cu-PDA or Ag-PDA) or incorporated on the surface of PDA (Cu@PDA or Ag@PDA). Cu@PDA and Ag@PDA showed stronger antimicrobial activity than Cu-PDA and Ag-PDA due to the NPs exposure to the bacteria. These nanocomposites showed very iii low cytotoxicity with cell viability of over 80 % at concentrations as high as 250 μg/mL. However, a drastic decrease in cell viability was observed when the concentrations of Cu@PDA and Ag@PDA were increased above 250 μg/mL. Taking advantage of the strong biological activity exhibited by Cu and Ag NPs, bimetallic nanoalloys of these two metals were prepared. Nanoalloys with a fibrous shape were obtained as bimetallic nanofibres (BNF). The mole ratio of Cu:Ag was found to have an effect the antimicrobial activity of the BNFs. The BNFs prepared with a mole ratio of 1:2 (BNF-2) exhibited a strong antimicrobial activity compared to 1:1 (BNF-1) and 2:1 (BNF-3). Furthermore, the BNFs showed minimal cytotoxicity towards the BHK-21 cells at low concentrations (7.8 μg/mL), with the cell viability ranging between 75-90 %. Compared to BNF-1 and BNF-2, BNF-3 was found to have a negative impact on cell viability when the concentrations were increasing. The novel and porous 3D scaffolds were prepared by coating chitosan/gelatine (CS/Gel) scaffolds with PDA using the freeze-drying method. This was followed by decorating the surface of the scaffolds with either Ag or Cu NPs, in situ. The presence of the catechol functional group inherent from PDA facilitated the reduction of Ag ions to form pure zerovalent Ag NPs on the surface of the scaffolds. However, to reduce Cu ions to form Cu NPs, an access reducing agent (hydrazine) was added. The scaffolds showed reasonably high fluid uptake (FU) with time-dependent biodegradability, a property that would be advantageous in controlling wound exudates. These scaffolds also showed excellent antimicrobial activity against E. coli and S. aureus with low cytotoxicity towards human fibroblast cells. Taken together, the designed scaffolds could act as a barrier from the external environment, help prevent bacterial infections and further accelerate skin cells regeneration. The most important feature of these scaffolds is their potential ability to penetrate deep wounds and provide a conducive environment for skin cells to regenerate without any difficulties from bacterial colonization.
Archiving Visibility Data Using Lossy Baseline-Dependent SVD Techniques
(University of the Witwatersrand, Johannesburg, 2025-06) Ramanyimi, Mukundi; Atemkeng, Marcellin; Makhathini, Sphesihle
Modern radio interferometer arrays, such as the MeerKAT [1], the Australian Square Kilometre Array Pathfinder (ASKAP) [2, 3], the Low Frequency Array (LOFAR) [4], the Murchison Widefield Array (MWA) [5, 6], and the upcoming Square Kilometre Array Observatory (SKAO) [7], generate large volumes of data due to their high temporal and spectral resolutions, large number of baseline configurations, and wide bandwidths. Managing these data volumes poses substantial challenges in terms of storage and processing. To address the growing costs, averaging techniques are widely used to reduce data sizes. However, averaging leads to signal loss in radio interferometric images, resulting in smeared or blurred source emissions and reduced source amplitudes. Moreover, the extent of this smearing is baseline-dependent, as the signal phase depends on baseline length. Specifically, longer baselines are more affected than shorter ones. This is addressed by Baseline Dependent Averaging (BDA), which applies variable averaging intervals - longer for shorter baselines and shorter for longer baselines. BDA achieves high data volume reduction since radio interferometers generally have more shorter baselines, which can be aggressively averaged with minimal smearing effects. However, BDA changes the time-frequency grid structure of the data, making it incompatible with the standard storage format in the field, the Measurement Set (MS). A promising approach to data compression was presented by Atemkeng et al. [8], who developed a compression technique based on Singular Value Decomposition (SVD). This approach exploits the inherent structure of raw visibility data, representing it as a low-rank matrix approximation where each component corresponds to a specific Fourier component of the sky distribution. By approximating the data with a reduced rank, the essential features of the original data can be captured using fewer components, effectively reducing data size. In this work, we build on the methods introduced by Atemkeng et al. [8], specifically evaluating the effectiveness of SVD in compressing large volumes of data while preserving image quality and data fidelity for long-term archival. Although our study focuses on the MeerKAT telescope, the approach can be adapted for use with any other radio telescope. Our findings demonstrate that for a bright point source (1 Jy), whether located at the phase centre or away from it, the data features can effectively be captured using a single component, recovering over 99.90% of the source amplitude and achieving a data size reduction of over 97%. For fields with multiple sources, the features can be fully captured using 3-4 components out of 24, recovering over 99.90% of the source amplitude for a source at the edge of the Field of View (FoV), which is around 1.1 deg for the MeerKAT at a frequency of 1.4 GHz. This results in a data size reduction of over 91%. Additionally, we found that the source or field direction does not impact SVD compression. On the other hand, the Signal to Noise Ratio (SNR) significantly affects SVD compression. For sources with low SNR or faint sources, all components are required to recover more than 97% of the source amplitude, making the compression ineffective. In such scenarios, it would be more advantageous to first denoise the data or to use BDA.
Comprehensive contributions of the informal sectors in Solid waste management Systems: A case study of Central Johannesburg
(University of the Witwatersrand, Johannesburg, 2025-02) Pursooth, Takshita; Kubanza, Nzalalemba Serge
The 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.
Cross-domain few-shot classification for remote sensing imagery
(University of the Witwatersrand, Johannesburg, 2025-04) Pillay, Christopher Wayne; Bau, Hairong
Deep learning has proven highly effective for scene classification tasks when substantial quantities of labelled data are accessible. However, performance decreases when applied to domains such as remote sensing which typically possess a limited quantity of labelled data across available datasets. Few-shot learning has been developed as one of the promising solutions to this problem. It has the ability to recognise new categories with minimal labelled examples, but it assumes that the training and testing data will exhibit identical feature distributions. This assumption is unrealistic in real-world contexts where data can originate from different domains and poses a challenge when a significant domain shift exists between the training and testing data. This dissertation aims to address these limitations by proposing the Cross-Domain Attention Network (CDAN). It is a network designed specifically to solve the issues that arise when there is a limited quantity of labelled data available and a significant domain shift exists between the training and testing data. The network proposed consists of a prototypical network as the base and three additions that contribute to the accurate scene classification of remote sensing imagery. Firstly, a cross-domain data augmentation technique is proposed with few-shot learning to reduce domain shift. The cross-domain data augmentation technique facilitates enhanced knowledge transfer between domains and increases the adaptation ability of the network, whereas few-shot learning reduces the network’s reliance on large labelled datasets. Secondly, a dynamic and focused attention module is proposed to improve discriminative capacity of the network by increasing the focus on important channels and spatial regions within images during training. Thirdly, an adaptive task aware loss is proposed to further enhance the network’s adaptive capacity by leveraging information in few-shot training tasks. Extensive experiments are carried out with different remote imaging classification datasets (RSICB, AID and NWPU-RESISC45) to prove that the proposed network alleviates concerns in a cross-domain few-shot (CDFS) classification setting.
What Are B-jets and What Can We Do With Them? A beauty-ful exploration of b-jets
(University of the Witwatersrand, Johannesburg, 2025-04) Nzuza, Wandile Siyamthanda; Kar, Deepak
In the Standard Model of particle physics, the bottom quark is one of the six quarks. It belongs to the third generation of quarks, alongside the top quark. The b-quark has a charge of - 1/3 of the elementary charge, making it negatively charged, and a mass of 4.2 GeV significantly greater than the up and down quarks, but smaller than that of the top quark. At the LHC, two protons are accelerated close to the speed of light in a head-on collision and as a result there are final states with thousands of hadrons. This means that there are jets everywhere. Jets are not fundamental objects observed in the final state but are a cone-like structure constructed to help deal with the large number of hadrons in final states. Jets containing b-hadrons are known as b-jets. The reason that final states with b-jets are of interest is because they result in much less ambiguous collider signatures which can assist in reducing the background significantly. The results presented are from various studies done using b-jets. We started off with a study of bottom-quark-philic semi-visible jets, followed by a measurement of b-jet cross-section as a function of missing transverse momentum using data collected by the ATLAS detector in Run 2 of the LHC and lastly two Performance Studies done of heavy-flavour tagging in ALICE and ATLAS experiment at the LHC.
Engaging Collections: Libetshu in the Van Warmelo Collection, Ditsong National Museum of Cultural History, South Africa
(University of the Witwatersrand, Johannesburg, 2025) Nzimela, Yola Siyamthanda; Namono, Catherine
This thesis broadly examines curatorial practice of African ritual material culture within museum and related institutional collections in South Africa. Specifically, I focus on divination material known as libetshu, or Mankgwanyana, heir looms, in the Nicolaas van Warmelo collection, the Ditsong National Museum of Cultural History, Pretoria, South Africa. Although many communities from which ritual objects such as these divination materials originate still revere them as sacred, there is a lack of meaningful inclusion of source communities in curatorial decision-making mainly due to elitist or Eurocentric perspectives on culture due to colonial legacies and/or where curatorial practices reside with Western trained professionals. Globally and locally, limited accurate archival contextual data about such divination material constrains connecting the objects to source communities. This thesis therefore sought to enhance understanding of libetshu /Mankgwanyana as ritually activated divination material, to encourage appropriate curation that takes cognisance of their spiritual significance for communities that hold them sacred. Through use-wear analysis, semi-structured interviews with traditional practitioners and curators, and a curatorial justice framework, I show that libetshu / Mankgwanyana are divination materials used in ritual performances, are spiritual and require specific handling and curation. I find that whilst co-curation with source communities and stakeholders is essential, a blanket approach for ritual objects is insufficient as each divination material belongs to different ancestral lineages. These findings highlight the importance of epistemic restitution and demonstrate the effectiveness of a curatorial justice approach that promotes sensitive, respectful, and appropriate curatorial practices cognisant of the integrity of divination materials such as libetshu / Mankgwanyana in collections.

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