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Item Valorization of invasive water hyacinth for nutrients removal from eutrophic waterbodies and biochar production(2025-10) Tshikovhi, NA; Mudzanani, K; Phadi, T; Masindi, Vhahangwele; Foteinis, SAmong many plights caused by eutrophication, the overabundance of algae and aquatic plants constitutes external pressures and stresses mounted on aquatic ecosystems. Of the aquatic plants known to infest rivers and dams, water hyacinth is considered the most problematic due to its invasiveness that disrupts waterways and pose detrimental environmental and health risks. This non-native (alien or exotic) species is already impairing aquatic ecosystems in South Africa, while vast harvested quantities, currently considered a waste, further exacerbate the problem. However, when viewed under the circular economy and waste valorization lenses, water hyacinth can be an important resource. Here, this was used for biochar production, by examining different temperatures, with 500 °C providing high carbon content. HR-SEM-EDS, HR-TEM-EDS, and XRF revealed varying biochar compositions, all enriched with notable phosphorus levels. This reflects the highly degraded state of freshwater bodies in South Africa since water hyacinth is a known phosphorus hyperaccumulator. Thermal analysis revealed that the raw water hyacinth mainly (96 %) comprises water, while weight losses for biochar at 167–990 °C correspond to moisture and volatile matter removal. Finally, biochar yield decreased from 32.5 % at 300 °C to 24.7 % at 700 °C, confirming progressive devolatilization and carbon enrichment at higher temperatures. Overall, results suggest that water hyacinth, an invasive species that wreaks havoc in aquatic ecosystems, can be sustainably managed to improve freshwater quality through nutrients removal and then used for biochar production. The produced biochar could be a good candidate for (waste)water treatment (adsorption) and particularly soil amelioration, given its high phosphorus content, and carbon dioxide removal (CDR) capabilities.Item Privacy versus utility in federated learning: An experimental analysis of noise injection techniques(2025) Leope, NR; Eloff, JHP; Dlamini, Thandokuhle MFederated Learning (FL) enables decentralized model training, while maintaining the privacy of the underlying individual datasets. Therefore, FL can resolve some intrinsically privacy-sensitive challenges in domains, such as healthcare and finance. However, privacy preservation usually comes with a trade-off on the usefulness (i.e., utility) of the information. The research problem is how to optimize this inversely proportional trade-off balance between privacy and utility. This study uses an experimental comparative analysis, in a synthetic healthcare setting, of different noise types (i.e., Gaussian, Laplacian, Poisson, Uniform, and Exponential) injected on the client side at the input-feature level prior to local training to enhance privacy in FL. We explore the impact of these noise types on the privacy–utility trade-off in FL data. The findings indicate that although Laplacian, Poisson, and Exponential types of noise provides stronger obfuscation which often comes at the cost of utility. This confirms and amplifies the trade-off in maintaining the usefulness of the data against its privacy. More importantly, the findings also show that Gaussian noise generally offers the best trade-off between privacy and utility on this task, suggesting a practical default for privacy-aware FL in healthcare-like environments.Item The contribution of South African mining companies to the sustainable development goals: A knowledge synthesis from text mining(2025-12) Haywood, Lorren K; Oelofse, Suzanna H; Khan, Sumaya; Pelders, Jodi L; Maphalala, BusiThis study examines how the United Nations Sustainable Development Goals (SDGs) are prioritised and integrated within South Africa’s mining sector through an analysis of sustainability and integrated reports from the top 13 Johannesburg Stock Exchange-listed mining companies between 2020 and 2023. Using the SDG Mapper, a text-mining tool that quantifies direct and indirect references to all 17 SDGs, the research identifies focus areas and reporting gaps. Findings show a steady rise in SDG references over time, with SDG 13 (climate action), SDG 12 (responsible consumption and production), and SDG 8 (decent work and economic growth) dominating corporate disclosures. SDG 7 (affordable and clean energy) also features strongly, reflecting responses to climate risks and regulatory pressure through emissions reduction and renewable energy adoption. In contrast, SDG 6 (clean water and sanitation) and SDG 15 (life on land) have only recently gained traction, exposing uneven sustainability practices. SDG 3 (good health and well-being) receives moderate attention despite its prominence in global mining frameworks. The study highlights the need for a more balanced, integrated approach that addresses environmental, social, and governance dimensions, and advocates systems thinking to strengthen sustainable mining in South Africa and other emerging economies.Item A phenomenological methodology for wave detection in epidemics(2025-12) Brettenny, W; Holloway, Jennifer P; Fabris-Rotelli, I; Dudeni-Tlhone, Nontembeko; Abdelatif, Nontembeko; Le Roux, Wouter J; Manjoo-Docrat, R; Debba, PraveshIn both the management and modelling of epidemic outbreaks, the ability to determine the start of a wave of infections is of vital importance. Not only does this advantage the modelling of the outbreak, but, if done in real-time, can assist with a nation’s response to the disease. In this study, a bidirectional long-short-term-memory (Bi-LSTM) network is used to determine the start and end of the COVID-19 waves experienced in the district and metropolitan municipalities of Gauteng, South Africa, from 2020-2022 as well as the waves of the cholera outbreaks occurring in the Beira area of Mozambique between 1999 and 2005, in real-time. The problem of real-time scaling of the data prior to the first wave of an epidemic is addressed using globally available real-time information from first waves experienced in other countries and independent territories alongside the observed South African data. The use of the Bi-LSTM predicted starting dates is demonstrated for the second waves of COVID-19 infections experienced in Gauteng in 2020/21. Using the predicted starting dates, spatial-SEIR models are used to predict hospitalisations as a result of COVID-19 infections in each of the district and metropolitan municipalities of Gauteng. The fitted Bi-LSTM model demonstrates effectiveness in predicting the start and end dates of epidemic waves in real-time, allowing for pre-emptive disease modelling and predictions of spread. Moreover, it is shown that the use cases for the fitted model are not limited to COVID-19 studies, but can also be applied to other disease outbreaks that follow similar wave patterns.Item Scoping the progress of e-Government services in South Africa: A journey from implementation to adoption and recommendations for addressing challenges that impede or slow down progression(2025-07) Nunu, Vuyisa; Maremi, Keneilwe J; Thulare, TumisoThis paper explores the development of e-government services in South Africa, tracing the journey from initial adoption to implementation based on literature findings. It emphasizes the stages of e-government evolution, highlighting the key drivers that promote advancements and the challenges that impede progress. The purpose of this paper is to inform government officials and policymakers about the obstacles that negatively impact e-government initiatives. Through a scoping review, the research examines existing studies on the implementation and adoption of e-government, focusing on technological, social, and economic factors. The findings indicate significant progress in the implementation of e-government services, driven by technological advancements and policy measures. However, the adoption phase faces challenges, including issues related to the digital divide, inadequate technological infrastructure, and user resistance. The paper concludes with a set of recommendations aimed at supporting evidencebased decision-making and advancing digital transformation within the public sector. These recommendations are presented for the consideration of government authorities and policymakers to foster a more inclusive and efficient public administration.Item Phosphite inhibits Phytophthora cinnamomi by downregulating oxidoreductases and disrupting energy metabolism(2025) Prabhu, SA; Naicker, P; Duong, TA; Govender, Ireshyn S; Engelbrecht, J; Backer, R; Stoychev, SH; Van den Berg, NPhytophthora root rot caused by the hemibiotrophic oomycete, Phytophthora cinnamomi is a major biotic hindrance in meeting the ever-increasing demand for avocados. In addition, the pathogen is a global menace to agriculture, horticulture and forestry. Phosphite trunk injections and foliar sprays remain the most effective chemical management strategy used in commercial avocado orchards against the pathogen. Phosphite is known to counter P. cinnamomi both directly and indirectly through fortification of host defense. However, phosphite's direct mode of action is still not understood completely. This study identified a P. cinnamomi isolate GKB4 sensitive to phosphite (EC50 of 27.9 μg/mL) and investigated the direct impact of phosphite on this isolate through label-free quantitative SWATH-MS. Proteomics data analysis of untreated vs. phosphite-treated samples revealed that the xenobiotic affects the pathogen's growth by targeting the oxidoreductases whose abundance is significantly reduced. Further, perturbations in the energy metabolism and membrane/transmembrane proteins and transporters, and oxidative stress contribute to growth inhibition. The current study also identified increased putrescine biosynthesis, a polyamine, that when present at non-optimal concentrations could be cytostatic/cytotoxic. The differential expression of enzymes involved in the biosynthesis of secondary metabolites and the intermediates/precursors involved in their biosynthesis is an interesting finding that needs further investigation to ascertain their role in phosphite-induced stress. The pathogen's attempt to counter phosphite's growth-inhibitory effects—through upregulation of alternate bioenergetics pathways (amino acid catabolism and β-oxidation of fatty acids), mitochondrial translation and translocation machinery, peroxisomal proteins, and antioxidants—appears ineffective. This research furthers our limited understanding of the direct in vitro effects of phosphite on P. cinnamomi and has identified potential candidates for molecular functional investigation.Item Laser metal deposited Ti4822 hollow pipe: Experimental and computational modelling study(2025) Raji, SA; Tlotleng, M; Skhosane, Besabakhe S; Kanyane, LR; Popoola, API; Pityana, Sisa LGenerally, manufacturing valuable parts from General Electric's titanium aluminide (Ti-48Al-2Cr-2Nb; Ti4822) is extremely difficult. The difficulty is due to the alloy's poor room temperature castable and machining properties. To achieve functional parts from Ti4822 via cast and selective laser melting, built parts are hot isostatically pressed. Unfortunately, direct energy deposited Ti4822 parts are yet to be reported in open literature and hence this article wherein a 100 mm long pipe is laser metal deposited and investigated for use as a heat exchanger. Before printing, the theoretical model is used to predict geometric defects (tapering) and heat distribution. The results conclude tapering at around 30 mm and rapid increase in heat inputs (HIs). The microstructural analyses corroborated this observation, particularly the fracture analyses which indicated internal cracking, impurities and pores at moderate HI, and isotropic microstructure with elongation formed dimple grains at high HI position. Fracture is said to be transgranular, cleavage-like, and ductile-brittle overall. Nanoindentation results conclude that the pipe would withstand high stress due to high toughness. Pipe inner surface roughness is 5.190 μm, indicating acceptable pressure drops and therefore usable as a heat exchanger.Item Integrating socio-economic zones into water resource analysis under land use change and climate variability in the Okavango basin(2025) Kavhu, B; Mashimbye, ZE; Luvuno, Linda B; San, UThe impacts of land use/land cover (LULC) change and climate variability on surface water availability is critical for informing transboundary water management. However, most hydrological models overlook the socio-economic (SE) heterogeneity of basins, potentially leading to oversimplified or inaccurate conclusions. This study aims to analyze the value of integrating socio-economic zones into hydrological analysis when disentangling the effects of LULC change and climate variability on surface water yield in the Okavango Basin. Using the InVEST water yield model, we simulated surface water availability for the years 2004, 2013, and 2020, achieving strong agreement with observed discharge data (R2 = 0.88, p < 0.05). Results show a basin-wide decline in mean surface water depth from 459 mm in 2004 to 299 mm in 2020, a 35 % reduction, consistent with regional drying trends and increasing anthropogenic pressures. Climate variability emerged as the dominant driver of change, explaining 81.7 % and 78.5 % of water yield variation during 2004–2013 and 2013–2020, respectively. However, in highly modified zones such as SE 2, 7, and 13, LULC change accounted for over 50 % of the variation, underscoring the spatial heterogeneity of hydrological drivers. By incorporating socio-economic zoning, this study offers a more nuanced and policy-relevant understanding of surface water dynamics and supports the design of targeted, zone-specific water management strategies in transboundary contexts.Item Climate change-induced weather extremes and responses in South African National Parks: Insights from employees(2025) Maoela, Malebajoa A; Nhamo, G; Mutanda, GW; Dube, KClimate change poses significant challenges for South African national parks, affecting infrastructure, ecosystem services, and biodiversity. A study across 19 parks, including Kruger and Kgalagadi, examined these impacts using data collected from September 2020 to December 2021. Surveys with 244 park employees from conservation, tourism, and community development departments assessed perceptions of extreme weather events and their effects. The analysis highlighted extreme temperatures and drought as the most critical threats, with respondents’ years of service influencing their perceptions. These events disrupted infrastructure and tourist experiences, underscoring the need for adaptive strategies. The findings revealed varying opinions on park management’s preparedness, emphasising the importance of tailored resilience-building measures. Addressing climate change challenges requires enhancing technical capacities, early warning systems, and incorporating diverse perspectives into decision-making. Tailored strategies and increased financial support are essential to protect these vital conservation areas and ensure long-term sustainability.Item The impacts of woody encroachment on nature's contributions to people in North America and Africa: A systematic review(2025) Skhosana, Felix V; Stevens, N; Maoela, Malebajoa A; Archibald, S; Midgley, GFWoody encroachment is affecting nature's contributions to people (NCP) in grassy ecosystems around the world, but these impacts have not yet been well summarised. Moreover, the impacts of encroachment are likely to vary depending on the historical ecosystem dynamics, climatic conditions, encroacher species, and the temporal, spatial, cultural and socio-economic contexts, including the de pendence of communities on natural resources. To address these issues, we systematically reviewed the literature on the impacts of woody encroachment in Africa and North America, according to the three broad groups of the NCP framework: material, non-material and regulating NCP. The material NCP most adversely affected by woody encroachment was the re duction in herbaceous forage availability, leading to reductions in the number and products of livestock on both continents. The benefits of material NCP were largely experienced in Africa and constituted the provision of wood materials for fuel, building and forage. Negative impacts on non-material NCP, such as recrea tion, tourism and social amenities, were also reported for Africa. For regulating NCP, negative effects were reported on soil health, habitat availability and the regulation of hydrological NCP (in terms of water loss) in both continents. The regulating benefits were mainly carbon stocks in both continents, with North America reporting more than three times more positive cases than Africa. The benefits of woody encroachment, such as carbon stocks, must be under stood in the context of the highlighted diverse impacts on other NCP. Depending on the context (e.g. ecological, spatial, cultural or socioeconomic), the need for certain NCP such as livestock production, tourism revenue and water provision supports efforts to reverse woody encroachment.Item Simulation of the African ITCZ during austral summer seasons and ENSO phases: Application of an RCM derived from stretched grid ESM(2025) Ramotubei, Teke S; Landman, WA; Mateyisi, Mohau J; Nangombe, SS; Beraki, AFIntroduction: Climate predictability across timescales in a changing climate presents a unique opportunity and challenges for state-of-the-art climate models. The use of regional climate models (RCMs) forced with interactively coupled Earth System Models (ESMs) for the sub-seasonal, seasonal, and decadal predictions is an actively growing research area. Methods: The study explores a stretched-grid RCM constrained with an ESM which integrates a climate change signature. Spectral relaxation paradigm is applied to limit the climate drift within the range of the multi-model sea-surface temperature (SST) and sea-ice concentration (SIC) variability. The model retroactive ensemble simulations for November initialization are evaluated on the seasonal migration of the ITCZ during El-Niño and La-Niña phases, exploring both the spatial and zonal positions. The model is also evaluated on the ITCZ process’ characteristics that include the Hadley cell (HC), stream function and the subtropical jet stream (STJ) using quantitative methods. Results: The RCM and the driving ESM demonstrate skillful performance in identifying the seasonal trajectory of both the spatial and zonal migration of the ITCZ during El-Niño and La-Niña. Moreover, the RCM also demonstrates a good skill in determining both the descending edge of the HC and the STJ with the highest mean percentage error of 16.3 and 7.5% for the HC and STJ latitudes, respectively. Conclusions: The November initialization of the RCM skillfully simulates the seasonal migration of the ITCZ (and related characteristics) aligned to the observations and reanalysis datasets. Notwithstanding, the RCM manifests a tendency of more dynamic error growth relative to its driving ESM as the lead time increases. Furthermore, the RCM is also out of phase with a southerly shift of the stream function compared to the 500 hPa reanalysis stream function. The modeling framework offers process oriented and teleconnection studies. It also provides great potential for climate applications with suitable bias corrections techniques, albeit the source and mechanism of its dynamic error growth deserve further investigation.Item Fine-tuning a sentence transformer for DNA(2025) Mokoatle, Mpho; Marivate, V; Mapiye, D; Bornman, R; Hayes, VMSentence-transformers is a library that provides easy methods for generating embeddings for sentences, paragraphs, and images. Sentiment analysis, retrieval, and clustering are among the applications made possible by the embedding of texts in a vector space where similar texts are located close to one another. This study fine-tunes a sentence transformer model designed for natural language on DNA text and subsequently evaluates it across eight benchmark tasks. The objective is to assess the efficacy of this transformer in comparison to domain-specific DNA transformers, like DNABERT and the Nucleotide transformer. The findings indicated that the refined proposed model generated DNA embeddings that exceeded DNABERT in multiple tasks. However, the proposed model was not superior to the nucleotide transformer in terms of raw classification accuracy. The nucleotide transformer excelled in most tasks; but, this superiority incurred significant computing expenses, rendering it impractical for resource-constrained environments such as low- and middle-income countries (LMICs). The nucleotide transformer also performed worse on retrieval tasks and embedding extraction time. Consequently, the proposed model presents a viable option that balances performance and accuracy.Item Chromatographic separation and analysis of amidated vs. non-amidated novel heterologous produced exenatide using UPLC-QTOF-MS(2025) Steenkamp, Lucia H; Steenkamp, PExenatide is used for the treatment of type 2 diabetes. Exenatide is normally produced using solid or liquid phase chemical synthesis which requires protecting side chain groups. The C-terminal is then amidated while the protecting groups are still in place. The novel production of exenatide, using a microorganism with the correct coding sequence, does not require protecting groups. The exenatide is then amidated using a PAM enzyme system. An UPLC-QTOF-MS method was developed to separate and analyze the non-amidated exenatide molecule from the final active amidated exenatide. The non-amidated exenatide was produced using an expression construct comprising a carrier protein open reading frame (ORF) Yarrowia lipolytica lipase or truncated Bacillus halodurans flagellin cloned in frame with the coding sequence for exenatide. The non-amidated and amidated exenatide differ by 1 Dalton in mass and typically co-elute during analysis. The method developed was able to separate the two compounds and could be used to measure the amidated exenatide produced during the bioconversion. The aim of the study was to investigate the feasibility of producing exenatide and monitoring the amidation during the bioconversion for possible scale-up and commercialization. The results showed complete amidation of the glycine-extended heterologous exenatide. The reproducibility of the analytical method was evaluated and found that the retention times and peaks areas of the detected exenatide were stable, making this analytical method suitable for reaction monitoring.Item Development of a high-cell-density production process for a biotherapeutic yeast, saccharomyces cerevisiae var. boulardii, for use as a human probiotic(2025) Moonsamy, Ghaneshree; Singh, Sarisha; Roets-Dlamini, Yrielle; Baikgaki, Koketso K; Ramchuran, Santosh OSaccharomyces cerevisiae var. boulardii is a probiotic yeast widely recognized for its ability to enhance gut health and modulate a host’s microbiome. However, there are limited data on its large-scale cultivation in stirred tank bioreactors and subsequent downstream processing into a functional probiotic product. Different recipe formulations were evaluated and the recipe with the highest biomass yield and lowest process time was selected. Once the optimised batch was validated in the replicate batches, the statistical analysis indicated a high level of reproducibility, with low variability across key performance indicators such as biomass concentration (unit), CFU production (CFU.mL−1), and substrate utilization efficiency (g.g−1). The mean growth age in the bioreactor was 25.33 ± 1.16 h, with a CV of 4.56%, indicating minimal deviation between batches. Similarly, the final viable concentration exhibited a mean of 1.46 × 108 CFU.mL−1 with a CV of 11.68%, remaining within an acceptable range for biological processes, while the final biomass concentration had the lowest variability (CV of 3.94%) and a 95% CI of 12.134–13.266 g.L−1, highlighting the accuracy and consistency of the process. Productivity indicators, including cell productivity (growth time—biomass) and YPP (biomass), maintained low CV values (3.933% and 3.389%, respectively), reinforcing process efficiency and stability. The overlapping 95% confidence intervals across batches further confirmed that no statistically significant deviations existed, ensuring minimal batch-to-batch variability, and validating the scalability and robustness of the fermentation process. These findings provide strong evidence for the feasibility of large-scale probiotic yeast production that meets industrial production standards. The final freeze-dried product retained an 81% viability post-exposure to simulated gastrointestinal conditions, meeting WHO probiotic viability standards. These findings establish a scalable, optimized process for probiotic yeast production, with potential applications in biopharmaceutical manufacturing and functional food development, as confirmed by the techno-economic evaluations performed using SuperPro Designer®.Item Bio-Coal Briquetting as a potential sustainable valorization strategy for fine coal: A South African perspective in a global context(2025) Ramdas, Veshara; Njokweni, Sesethu G; Letsoalo, Machira P; Motaung, Solomon R; Ramchuran, Santosh OThe generation of fine coal particles during mining and processing presents significant environmental and logistical challenges, particularly in coal-dependent, developing countries like South Africa (SA). This review critically evaluates the technical viability of fine coal briquetting as a sustainable waste-to-energy solution within a SA context, while drawing from global best practices and comparative benchmarks. It examines abundant feedstocks that can be used for valorization strategies, including fine coal and agricultural biomass residues. Furthermore, binder types, manufacturing parameters, and quality optimization strategies that influence briquette performance are assessed. The co-densification of fine coal with biomass offers a means to enhance combustion efficiency, reduce dust emissions, and convert low-value waste into a high-calorific, manageable fuel. Attention is also given to briquette testing standards (i.e., South African Bureau of Standards, ASTM International, and International Organization of Standardization) and end-use applications across domestic, industrial, and off-grid settings. Moreover, the review explores socio-economic implications, including rural job creation, energy poverty alleviation, and the potential role of briquetting in SA’s ‘Just Energy Transition’ (JET). This paper uniquely integrates technical analysis with policy relevance, rural energy needs, and practical challenges specific to South Africa, while offering a structured framework for bio-coal briquetting adoption in developing countries. While technical and economic barriers remain, such as binder costs and feedstock variability, the integration of briquetting into circular economy frameworks represents a promising path toward cleaner, decentralized energy and coal waste valorization.Item Complementary effects of probiotics and stimbiotics inclusion on growth performance, protein utility, serum metabolites and behavioural observations in broiler chickens exposed to cyclic heat stress(2025) Mokonyama, RM; Marume, U; Moonsamy, GhaneshreeThe study investigated the complementary effects of probiotics and stimbiotics inclusion on growth performance, serum metabolites and behavioural responses in broiler chickens exposed to cyclic heat stress. Six hundred Cobb500 day-old-chicks were allocated to five dietary treatments: Standard broiler diet, with no inclusion of AGPs (NegControl); Standard broiler diet, with inclusion of AGPs (PosControl); Standard broiler diet + 0.01 % probiotics (Prob); Standard broiler diet + 0.01 % stimbiotics (Stim) and Standard broiler diet + 0.01 % probiotics and 0.01 % stimbiotics) (ProbStim). Each dietary treatment was replicated 8 times, with a pen holding 15 birds as the experimental unit. The experimental trial was conducted over three feeding phases: starter phase (day 1- 14), grower phase (day 15- 28) and finisher phase (day 29- 42). The birds were subjected to heat stress in the grower phase and finisher phase for 3 h (11:00- 14:00 h). Diet had no effect on ADFI in the starter, grower and finisher phase. Similarly, diet had no effect on ADG and FCR in both grower and finisher phase. The cumulative weight gain was consistently low in broiler chickens fed the Stim diet throughout the feeding phases, while those fed Prob diet had higher weights in week 2 and to 6. Dietary treatments did not affect protein consumed, protein efficiency ratio, specific growth rate and growth efficiency across all the feeding phases. Total cholesterol and triglyceride concentrations were significantly affected by diet (P < 0.05) with broiler chickens fed PosControl in non- stressed environment having the highest total cholesterol (3.90± 0.18) and triglyceride level (1.77± 0.12). With regards to behavioral response to heat stress induced discomfort, broilers fed PosControl (2.33±0.26) and Prob (2.33±0.26) exhibited increased pecking feed activity and increased tendencies of seeking cooler areas. Overall, the birds did not show signs of severe stress. In conclusion, Probiotics and Stimbiotics could be used in combination to replace of AGPs without negatively affecting productivity in broilers.Item Vaal’s microplastic burden: Uncovering the fate of microplastics in Emfuleni Municipality’s Wastewater Treatment Systems, Gauteng, South Africa(2025) Maleka, Tebogo; Greenfield, R; Muniyasamy, Sudhakar; Modley, L-AMunicipal wastewater treatment plants (WWTPs) in Gauteng, South Africa, are inadequately designed or optimized to effectively remove microplastics (MPs), resulting in approximately 80% of wastewater being discharged into aquatic ecosystems with insufficient treatment. This study evaluates the prevalence and abundance of MPs in municipal WWTPs and their subsequent introduction into receiving water bodies. Comprehensive sampling was conducted across three municipal WWTPs in the Emfuleni region of Gauteng province from October 2022 to July 2023. Initial MP identification and quantification were performed using light microscopy, while scanning electron microscope energy-dispersive X-ray spectroscopy (SEM/EDS) was employed to identify non-plastic particles and perform elemental analysis. The findings reveal significant seasonal variability in MP concentrations. The highest influent and effluent concentrations were recorded during October (spring), with influent values of 142 MPs/ℓ (WWTP 1), 124 MPs/ℓ (WWTP 2), and 132 MPs/ℓ (WWTP 3), and effluent concentrations of 120 MPs/ℓ (WWTP 1), 63 MPs/ℓ (WWTP 2), and 89 MPs/ℓ (WWTP 3). Conversely, the lowest MP concentrations were observed during April (autumn), with influent concentrations of 114 MPs/ℓ (WWTP 1), 141 MPs/ℓ (WWTP 2), and 78 MPs/ℓ (WWTP 3), and effluent concentrations of 99 MPs/ℓ (WWTP 1), 53 MPs/ℓ (WWTP 2), and 86 MPs/ℓ (WWTP 3). Fibers and filaments constituted the dominant MP morphology, primarily derived from polyester, nylon, and acrylic synthetic textiles. Dark-colored MPs, especially black, blue, and red particles, were predominant in the wastewater samples. This study underscores the critical role of WWTPs as conduits for MP contaminants into the environment and highlights the urgent need to develop and implement improved MP removal technologies in wastewater treatment systems. MP production is estimated to account for approximately 15–20% of total global plastic production, corresponding to an annual generation of approximately 52.5–80 million metric tons of MP. By addressing MP pollution, this research directly contributes to sustainability by promoting the protection of freshwater ecosystems, reducing anthropogenic pressures on aquatic biodiversity, and supporting the principles of sustainable development. The findings align with global and regional goals to enhance water quality management and promote sustainable urbanization practices in line with the United Nations Sustainable Development Goals (SDGs).Item Towards robust gesture-based control for mobile robots: Implementing and validating a limited recognition system on Voyager(2025) Botha, Natasha; Van Eden, Beatrice; Maweni, ThabisaGesture recognition plays a crucial role in human-robot interaction, allowing mobile robots to interpret and respond to non-verbal commands. This study presents the implementation of a limited gesture recognition system for the Voyager mobile ground robotic platform using a limited set of hand gestures. The system is validated in both simulation (Gazebo) and real-world environments and compared using metric such as recognition accuracy, latency, and user variability. This research highlights the challenges and potential solutions for deploying a limited gesture-based control in real-world robotic applications.Item Evaluation of a lightweight visual–inertial state estimator for GPS-denied environments(2025) Ramwell, A; Pretorius, A; Botha, NatashaUnmanned aerial vehicles are a stimulating and practically promising solution for automating tasks in inaccessible environments. An appealing minimal sensor suite for localisation (the first challenge in automation) is the combination of monocular camera and inertial measurement unit. Although visual localisation is a well-developed field, fiducial marker-less methods remain computationally expensive. In this study, a simple, lightweight visual–inertial state estimator is evaluated in physical experiments, achieving a mean positional and angular error of within 15 cm and 5°, respectively, in non-ideal conditions (periodic image loss and slow update rates). This study’s contribution is thus the development, description, and benchmarking of a stripped-down, practical localisation solution that is simple to understand and interface with. After some refinement, the system is expected to serve as a skills development tool and foundation for higher-level navigators.Item Practical implementation of Depth Anything V2 as a LiDAR alternative in robotics navigation(2025) Louw, Jakobus M; Verster, Jacobus J; Dickens, John SUnmanned aerial vehicles are a stimulating and practically promising solution for automating tasks in inaccessible environments. An appealing minimal sensor suite for localisation (the first challenge in automation) is the combination of monocular camera and inertial measurement unit. Although visual localisation is a well-developed field, fiducial marker-less methods remain computationally expensive. In this study, a simple, lightweight visual–inertial state estimator is evaluated in physical experiments, achieving a mean positional and angular error of within 15 cm and 5°, respectively, in non-ideal conditions (periodic image loss and slow update rates). This study’s contribution is thus the development, description, and benchmarking of a stripped-down, practical localisation solution that is simple to understand and interface with. After some refinement, the system is expected to serve as a skills development tool and foundation for higher-level navigators.