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Item Evaluating the rate of migration of an uranium deposition front within the Uitenhage Aquifer(1999-08-27) Vogel, JC; Talma, AS; Heaton, THE; Kronfeld, JThe solubility of uranium in groundwater is very sensitive to changes in redox conditions. Many secondary (sandstonetype) uranium deposits have been formed when soluble U has precipitated after encountering reducing conditions in the subsurface. In the groundwater of the Uitenhage Aquifer (Cape Province, South Africa), 238U-series isotopes were used to assist in studying the history of the reducing barrier. Uranium isotopes were used to determine the present position of the barrier. Radium and radon were used to evaluate the path of migration that the front of the oxygen depletion zone has taken over the past 105 years. During this time the reducing barrier has moved, leaving in its wake a trail of U in various stages of secular equilibrium with its daughter 230Th. The 226Ra daughter of 230Th is not very mobile. Its growth upon the aquifer wall is reflected in the Rn content of the water. This in turn, due to the relatively great age of the water, indicates the extent of the 230Th ingrowth (from precipitated U) that took place before the barrier migrated.Item Cape Point GAW Station Rn-222 detector: factors affecting sensitivity and accuracy(2002) Brunke, EG; Labuschagne, C; Parker, B; Van der Spuy, D; Whittlestone, SSpecific factors of a baseline Rn-222 detector installed at Cape Point, South Africa, were studied with the aim of improving its performance. Direct sunlight caused air turbulence within the instrument, resulting in 13.6% variability of the calibration factor. Shading the instrument eliminated this effect. A residual temperature dependence of the calibration factor was reduced to negligible levels with an improved photomultiplier tube. A superior detector head permits field servicing of the instrument, and has reduced one component of the instrumental background by a factor of 2. The other component probably constitutes thoron emissions from the stainless steel walls. The detection limit of the instrument could be reduced from its current 33 to 20 mBq m(-3) if the thoron were to be eliminated.Item A systematic literature review: The influence of technical, operational and structural factors on the adoption of digital agriculture among small-scale farmers in Sub-Saharan Africa(2026-07) Chesi, ALC; Cho, Moses A; Cho, MNA; Ramoelo, AThis systematic review paper examines how technical, operational, and structural factors influence the adoption of digital agriculture among small-scale farmers in Sub-Saharan Africa. Guided by PRISMA protocols, the study applies a hybrid thematic synthesis across six dimensions: technical, operational, policy and regulatory, governance, social and cultural, and environmental. The findings indicate that digital tools can generate substantial benefits, including yield increases of 10–30% (documented primarily for mobile-based advisory services and precision input management in East African horticulture and West African cocoa value chains) and price gains of 15–25%, with adoption rates of 70–80% in settings characterised by robust infrastructure, strong institutional support, and effective value chain integration. However, these benefits are unevenly distributed and tend to concentrate in “islands of adoption” characterized by robust infrastructure, strong institutional support, and effective value chain integration. While technical (94.9%) and operational (91.5%) factors dominate the literature, their impact is constrained by persistent structural barriers, including weak policy implementation (79.7%), fragmented governance systems (76.3%), and socio-cultural exclusion—such as gender disparities, age-related digital divides, and language misalignment (71.2%). The review identifies five minimum conditions for meaningful adoption: (i) affordable connectivity and access to digital devices; (ii) context-specific digital literacy; (iii) culturally relevant, user-centred design; (iv) robust institutional ecosystems; and (v) enabling policy and financial frameworks. Overall, the findings underscore that digital agriculture adoption is a socio-technical process shaped not only by technological innovation but also by institutional arrangements and user capabilities. Comparative cases, such as Kenya’s Farm.ink and the less successful EZ Farm initiative, further highlight the importance of integrated, context-responsive approaches to ensure that digital agriculture enhances, rather than marginalizes, small-scale farmers.Item Cannabis sativa L. biomass valorization as a strategic bioresource for South Africa’s circular bioeconomy: Integrating biorefinery pathways and green extraction(2026-07) Motsa, Vuiswa L; Seedat, N; Mekuto, L; Sekoa, PSouth Africa’s legalized Cannabis Sativa L. industry generates substantial biomass waste, including post-harvest materials such as stalks, leaves, roots, and seeds, as well as post-extraction residues rich in lignocellulosic components (cellulose, lignin, hemicellulose) and functional compounds (fibers, phenolic compounds, and proteins) which remain largely unvalorized. This review critically and systematically examines valorization pathways for Cannabis sativa L. biomass within the context of a circular bioeconomy, focusing on its potential as a bioresource amid South Africa’s evolving regulatory, agricultural, and industrial landscape. A systematic scoping review of 65 peer-reviewed studies (2018–2025) was conducted using international databases to evaluate biochemical and thermochemical conversion, integrated biorefinery strategies, and green extraction methods such as supercritical CO2 extraction, microwave-assisted extraction (MAE), and ultrasound-assisted extraction (UAE). Compositional analysis indicates that lignocellulosic fractions from Cannabis sativa L., particularly bast fibers and hurds, are well-suited to cascaded biorefinery applications, enabling the recovery of cannabinoids, carbon-based materials, and bioenergy. However, several challenges persist, including biomass recalcitrance to enzymatic hydrolysis, inconsistent feedstock availability, and the lack of a standardized protocol within South Africa’s regulated environment. Techno-economic assessments (TEA) highlight the need for financial incentives, decentralized infrastructure, and cohesive policies among government entities, including DALRRD, SAHPRA, and DTIC. The review proposes a South African collaboration framework linking policy with research-based process design. Key gaps include the need for life cycle assessment (LCA) and TEA validation at the pilot scale, characterization of landrace cultivars, and development of accessible pretreatment technologies for smallholders.Item Deep learning for carotid Doppler spectra classification(2026-04) Bhikha, Charita B; Dhuness, Kahesh; Mennen, M; Jamieson-Luff, N; Ntusi, NAB; Wheatley, Richard ECardiovascular disease (CVD) remains a global health challenge, with limited specialist access in low- and middle-income countries hindering early detection. Carotid Doppler ultrasound offers promise for screening in non-specialist settings. However, spectral Doppler lacks the anatomical context provided by duplex ultrasound, making it challenging to determine which carotid vessel is being assessed. This study focuses on accurately identifying signals from the common, internal, and external carotid arteries (CCA, ICA, and ECA) based solely on Doppler spectra. This forms a critical step for subsequent disease classification. A clinical study enrolled 398 participants who underwent bilateral carotid Doppler examination (198 healthy controls, 200 with CVD). Several classifiers were evaluated including i) five deep convolutional neural networks (CNN) utilizing transfer learning on spectral images, and ii) conventional machine learning classifiers applied to the maximum frequency envelope and extracted features. The best performing classifier was a CNN (GoogLeNet) which achieved a mean area under the curve (AUC) of 0.929, effectively distinguishing between carotid artery segments. It exhibited f1-scores of 0.830, 0.803 and 0.764 for the ICA, ECA and CCA, respectively. Explainable AI tools (GradCAM and LIME) provide intuitive visual insights into these predictions. This study addresses a previously unsolved problem of automated carotid artery segment identification using spectral Doppler waveforms alone. When incorporated into automated screening tools, this approach provides a low-cost, specialist-independent pathway for earlier CVD detection, particularly suited to resource-constrained environments.Item Modelling of spatially misaligned wastewater-based surveillance data(2026-08) Torresa, M; Docrata, R; Rose, D; Le Roux, Wouter J; Schaefer, Lisa M; Jele, Jabulani; Dudeni-Tlhone, Nontembeko; Holloway, Jennifer P; Debba, Pravesh; Ludick, Chantel JWastewater-based epidemiology (WBE) has emerged as a promising approach to infectious disease modelling and early detection of disease outbreaks in general. Herein, the application of this approach to COVID-19 is explored through spatio-temporal models. The goal of predicting COVID-19 cases at a small administrative area level (sub-place) while using data collected at catchment area level introduces the issue of spatial misalignment. Spatial misalignment in the data must be accounted for by the modelling process, as is the case for many spatial disease models. Appropriate handling of the data requires disaggregation and matching of different spatial regions. The models are developed in a Bayesian framework using the INLA package in R, which is particularly intuitive in the context of latent Gaussian mixed models (LGMM). Misalignment is explored using a distance based approach which incorporates uncertainty as a component of the LGMM. COVID-19 cases were modelled at sub-place level and spatio-temporal trends were explored. The best performing model was able to utilise a link between the wastewater data and the COVID-19 cases. The modelling approach deals with data available at different spatial resolution, data covering misaligned and overlapping spatial areas, disaggregated and missing data, thereby accounting for complexity of real data. The methodology provides a novel structure to deal with the intricacy of the sampled wastewater and related data, and poses a proof of concept for wastewater-based spatial modelling for disease surveillance.Item Mycelium-based leather-like material from Absidia koreana grown on agro-residues: Process optimisation, functionalisation, and material performance(2026-07) Nguena-Dongue, B-N; Amobonye, A; Muniyasamy, Sudhakar; Pillai, SDeveloping sustainable, eco-friendlier leather-like material using fungal mycelium is a promising solution to environmental, animal welfare, and human health concerns associated with the traditional leather industry. Thus, having identified Absidia koreana BN223 as a fungus with potential for mycofabrication, its growth and biomass production were optimised using readily available agro-residues. Subsequently, the mycelium was processed into a biomaterial with a leather-like appearance through deacetylation, crosslinking, plasticisation and surface coating; after which selected functional properties were evaluated. Results indicated wheat bran and casein as the most effective carbon and nitrogen sources, respectively, for A. koreana mycelium production. Further, response surface methodology-based optimisation culminated in a 2.7-fold increase in biomass. The processed mycelial mat exhibited thermal stability up to 230 °C with increased compactness and uniform morphology relative to the raw mycelium, indicating improved surface consolidation. The leather-like material had an ultimate tensile strength, elongation at break and Young's modulus of ∼3.18 MPa, 3.53% and 159.65 MPa, respectively, while also exhibiting a flexural rigidity of 89.73 μNm, a bending modulus of 16.01 MPa, and a critical tearing energy of 2.4 N/mm. Furthermore, benchmarking the material properties within the ANSYS framework indicated a comparable mechanical performance to the commercial leather analogues, Muskin and Pinatex. The biomaterial also displayed enhanced hydrophobicity, with water absorption decreasing 15.22 times compared to the untreated material, and water contact angle up to 96.23 °C. These findings lay the foundation for a waste-to-wealth approach to producing sustainable mycelium-based materials, with potential applications in the fashion industry, especially in low-stress leather applications and packaging, among others. Future studies on life cycle assessments and technoeconomic analyses are needed to validate the cost-effectiveness and environmental friendliness of the developed material.Item Bioplastic films from Sargassum oligocystum and Eucheuma spinosum seaweeds: Preparation, thermal degradation, and kinetics analysis(2026) Ngonyamana, A; Nyoni, B; Mnyango, JI; Kandirai, IT; Hlangothi, SP; Muniyasamy, SudhakarIn the framework of a circular economy, bioplastics derived from renewable natural resources are gaining attention as sustainable alternatives to conventional plastics. This study reports the synthesis of bioplastic films from brown seaweed (Sargassum oligocystum) and red seaweed (Eucheuma spinosum) via alginate extraction, followed by structural and thermal characterization. Fourier-transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and differential scanning calorimetry results confirmed that Sargassum oligocystum- based bioplastic exhibited properties comparable to the commercial sodium alginate-derived bioplastic. Additionally, thermogravimetric analysis results revealed that Sargassum oligocystum decomposed in a single step near 220 C, whereas Eucheuma spinosum degraded in two steps at ≈ 280 films showed decomposition at ≈ 225 ◦ ◦ C and 330 C (Sargassum oligocystum) and 250 ◦ ◦ C. The corresponding bioplastic C (Eucheuma spinosum). Kinetic studies indicated nucleation-controlled thermal degradation, with activation energies of 20.0 to 26.8 kJ/mol for Eucheuma spinosum and 43.8 to 49.5 kJ/mol for Sargassum oligocystum bioplastics. These findings demonstrate the potential of seaweed-derived bioplastics as renewable, thermally stable materials and provide insights into their degradation mechanisms for future material optimization and practical applications.Item Improved performance and compost biodegradation of PLA/PBAT blend and PLA/PBAT compatibilized blends with algae as a reinforcer(2026-02) Letwaba, J; Muniyasamy, Sudhakar; Rakku, N; Mavhungu, LMelt blending of biodegradable polyesters such as poly (lactic acid) (PLA) and poly (butylene adipate co-terephthalate) (PBAT) with a compatibilizer and natural filler offers a chance to develop biodegradable bio-composites with improved performance. In this study, we examined how PLA/PBAT blends behave during ultimate biodegradation (mineralization), both with and without compatibilizer and algae as a reinforcement, under controlled composting conditions using carbon dioxide (CO2) respirometry techniques. Throughout the biodegradation process, the disintegration behaviour, thermal, chemical, and morphological properties of test samples before and after biodegradation were analyzed using FTIR, TGA, DSC, and SEM techniques. The results from CO2 biodegradation showed that PLA/PBAT blend exhibits a higher rate of biodegradation compared to neat PLA and PBAT. The addition of algae to a compatibilized PLA/PBAT blend showed an enhanced biodegradation rate due to hydrolytic cleavage and microbial assimilation. This was further supported by the disintegration test, where algae-reinforced composites showed fragmentation within 30 days. FTIR, TGA and SEM analysis revealed the structural changes that occurred during biodegradation, highlighting the role of algae in affecting the thermal stability and surface morphology. After the compost biodegradation step, eco-toxicity seed germination was conducted on the test samples. Plant seed germination test results confirmed that all test samples achieved maximum germination. This indicates there were no toxic residues, suggesting that the degraded materials are environmentally safe. Overall, this study contributes to the understanding of biodegradation mechanisms and the ecological impact of bio-based polymer composites as eco-friendly materials and products.Item Remote sensing delivers tropical forest resilience monitoring for the Global Biodiversity Framework(2026-07) Aguirre-Gutiérrez, J; Cortes, I; Nunes, MH; Cho, Moses A; Takeshige, R , J Cortes; Malhi, YTropical forests sustain a disproportionate share of global biodiversity and of nature’s contributions to people, yet they are increasingly destabilized by interacting pressures from climate change, land-use change and intensifying disturbance regimes. Understanding and monitoring forest resilience — the capacity to resist, absorb, recover from and adapt to disturbance — requires scalable approaches that integrate biodiversity, ecosystem structure and function across space and time. In this Review, we discuss how the essential biodiversity variables (EBV) framework, enabled by satellite remote sensing, has improved understanding of forest resilience under global environmental change. Remotely sensed EBV proxies derived from multispectral, thermal, hyperspectral, radar, light detection and ranging (LiDAR) and solar-induced fluorescence observations capture multiple facets of biodiversity and ecosystem dynamics. However, scale dependence, observational biases and the limited capacity of current EBVs to resolve fine-grained biological and mechanistic processes underpinning resilience (particularly species turnover and functional reassembly) are critical limitations. Emerging opportunities, including data fusion, next-generation satellite missions and integration with in situ observations, will advance the operationalization of EBV-based resilience monitoring, particularly in the context of the Kunming–Montreal Global Biodiversity Framework.Item Advancing cancer research in resource-limited settings: Perspectives from emerging voices across continents(2026-07) Sanchis, P; Aguilar-Cortes, DC; Kannan, B; Malik, R; Sabater, A; Alragheb, BA; Blessing, OO; Leal, LF; Fusco, M; Takundwa, MutsaCancer is a global disease, yet a paradox persists: The most advanced research ecosystems are concentrated in countries with lower disease burden, whereas low- and middle-income countries (LMIC)—carrying 70% of the global cancer burden—face major constraints in research capacity. Closing this gap is essential for equitable progress in cancer prevention, diagnosis, and treatment. Researchers in LMICs are creatively adapting established technologies, research pipelines, and collaborative models from higher-resource settings to local solutions. In this study, 25 American Association for Cancer Research Global Scholar-in-Training Award recipients from LMICs share how cancer research is advancing within resource-limited settings, focused on (i) infrastructure and resources, (ii) training and talent retention, (iii) funding and sustainability, and (iv) cultural and social barriers. We identified shared challenges and cross-cutting solutions, discussed gaps, and suggested steps to further advancing cancer research. We emphasized locally led innovation, strategic partnerships, and community engagement. These perspectives offer a framework for inclusive, synergistic approaches to strengthening cancer research and accelerating impact where it is needed most.Item Exploring the antimicrobial potential of a novel phage-derived lytic protein against pseudomonas aeruginosa(2026-03) Mtimka, Sibongile; Malatji, Kanyane B; Sakyi, PO; Nogbou, ND; Musyoki, AM; Mamputha, Sipho; Kwezi, Lusisizwe; Kwofie, SK; Pooe, OJ; Tsekoa, Tsepo LThe escalation of bacterial resistance to existing antibiotics represents a growing global health challenge, exacerbated by the widespread misuse of antimicrobial agents. As a result, alternative antibacterial strategies are increasingly being explored, including phage-derived lytic proteins. In this study, we report a preliminary characterisation of a novel phagederived lytic protein identified through computational screening of bacteriophage genome sequences. A putative open reading frame, designated SM07 (1383 bp), was selected from bacteriophage sequences contributed by the University of KwaZulu-Natal to a global phage repository. The gene was synthesised, sub-cloned into the pET-30b(+) vector with an N-terminal histidine tag, and recombinantly expressed in Escherichia coli BL-21(AI) cells. The protein was purified using affinity and ion-exchange chromatography. Purified SM07 exhibited in vitro antimicrobial activity against Pseudomonas aeruginosa, with a minimum inhibitory concentration of 4 µg/mL, while no significant cytotoxic effects were observed in Vero kidney cells at concentrations substantially above the effective dose. Together, these findings provide initial evidence supporting the antimicrobial potential of SM07 and highlight phage-derived lytic proteins as candidates for further investigation as alternative agents against P. aeruginosa-associated infections.Item Blockchain forensics and regulatory technology for crypto tax compliance: A state-of-the-art review and emerging directions in the South African Context(2026-01) Ramazhamba, Pardon T; Venter, HThe rise in Blockchain-based digital assets has transformed the financial ecosystems, which has also created complex governance and taxation challenges. The pseudonymous and cross-border nature of crypto transactions undermines traditional tax enforcement, leaving regulators such as the South African Revenue Service (SARS) reliant on voluntary disclosures with limited verification mechanisms, while existing Blockchain forensic tools and regulatory technologies (RegTechs) have advanced in anti-money laundering and institutional compliance, their integration into issues related to taxpayer compliance and locally adapted solutions remains underdeveloped. Therefore, this study conducts a state-of-the-art review of Blockchain forensics, RegTech innovations, and crypto tax frameworks to identify gaps in the crypto tax compliance space. Then, this study builds on these insights and proposes a conceptual model that integrates digital forensics, cost basis automation aligned with SARS rules, wallet interaction mapping, and non-fungible tokens (NFTs) as verifiable audit anchors. The contributions of this study are threefold: theoretically, which reconceptualise the adoption of Blockchain forensics as a proactive compliance mechanism; practically, it conceptualises a locally adapted proof-of-concept for diverse transaction types, including DeFi and NFTs; and lastly, innovatively, which introduces NFTs to enhance auditability, trust, and transparency in digital tax compliance.Item The impact of team dynamics on software quality and productivity: Evidence from South Africa(2026-03) Vhahangwele, T; Isong, B; Abu Mahfouz, Adnan MISoftware quality and productivity are influenced not only by technical practices but also by the social dynamics within development teams. This study investigates the combined effect of team dynamics, including trust, communication, collaboration, diversity, and conflict resolution, and software development practices on project outcomes. A mixed-methods design combined regression, Spearman’s Rho, and thematic analysis of survey data from 124 South African software professionals. The findings indicate that trust is the strongest positive predictor of software quality and productivity, while communication effectiveness and the use of collaboration tools also improve software outcomes. Equally, unstructured collaboration, excessive planning meetings, and poorly managed communication channels negatively affect performance. Diversity and effective conflict resolution were positively associated with productivity and efficiency. Thematic analysis corroborated these findings, illustrating how unclear communication, low trust, and dysfunctional collaboration lead to delays, rework, and lower quality. The study confirms that successful software outcomes emerge from the alignment of social and technical subsystems, highlighting the critical role of team dynamics in realising the full potential of software development practices. It contributes empirical evidence from an understudied developing-country context and proposes a socio-technical framework to enhance software quality and productivity.Item Determining the sensitivity of Sentinel-2 bands to optically and non-optically active water quality parameters under high- and low-flow conditions in the cradle of Humankind World Heritage Site, South Africa(2026-04) Ngamile, S; Kganyago, M; Madonsela, Sabelo; Mvandaba, VuyelwaAccess to clean water is a global challenge, particularly in the Global South, where scarcity and pollution threaten human and ecosystem health. Traditional water quality monitoring is limited in spatial and temporal coverage, while satellite remote sensing provides an alternative for assessing optically and non-optically active water quality parameters (WQPs). This study evaluated the sensitivity of Sentinel-2 MSI bands to WQPs in the Cradle of the Humankind World Heritage Site, South Africa, an area impacted by acid mine drainage. In situ measurements of DO, EC, pH, temperature, chlorophyll-a, and suspended solids were collected from 40 sites under high- and low-flow conditions. The Sentinel-2 images were atmospherically corrected, resampled to 10 m, and the values were extracted to the sampling points. Using multiple linear regression, random forest, and partial dependence plots methods, results showed that DO strongly influenced most bands, while suspended solids dominated the optically active band responses.Item RBBP6 and cancer: From molecular mechanisms to clinical implications(2026-05) Ubanako, PN; Nweke, EE; Nsingwane, Z; Monchusi, Bernice A; Penny, CRetinoblastoma binding protein 6 (RBBP6) is a 200 kDa E3 ubiquitin ligase that performs several biological functions and plays a role in tumorigenesis. RBBP6 is overexpressed in several types of tumors, including lung, colorectal, breast, cervical, hepatocellular, and esophageal cancers, suggesting its association with malignant progression. Moreover, this increased expression has been associated with clinicopathological parameters in lung, colorectal, cervical, and ovarian cancers. This review captures the molecular functions of RBBP6 and the mechanisms by which aberrant RBBP6 expression and function influence cancer development and therapeutic response. These mechanisms include its ability to interact with E3 ligase substrates, Jun N-terminal kinase (JNK), noncoding RNAs, and DNA damage-associated proteins to promote cell proliferation, stemness, cell cycle progression, and metastasis. Wealso evaluated the prognostic and predictive significance of RBBP6 as a potential cancer biomarker and its suitability as a molecular target in cancer. This is the first review that comprehensively explores the multifaceted molecular mechanisms by which RBBP6 influences cancer progression in several cancer types.Item Localized brightness–shape–moisture soil parameterization for improved PROSAIL-5 canopy simulation(2026-03) Bonnet, Wessel J; Cho, Moses A; Chirwa, PW; Masemola, CThe mapping and modeling of canopies is important for the understanding, monitoring, and management of vegetation systems. To effectively model or simulate canopy spectra at the hyperspectral level, background soil spectra must first be simulated accurately. Spectrometer data simulation such as this will become increasingly relevant as newer imaging spectroscopy missions such as PRISMA and AVIRIS-NG start to produce more data sets. In this study, the brightness–shape–moisture (BSM) radiative transfer model (RTM) with localized parameter distributions was used in conjunction with the PROSAIL-5 RTM to simulate canopy spectra for different biomes in the semiarid regions of Southern Africa as captured with PRISMA or AVIRIS-NG sensors. It is hypothesized that a PROSAIL-5 RTM with biome-specific BSM parameters can more accurately simulate PRISMA and AVIRIS-NG spectra than a PROSAIL-5 model simulated with the default soil spectrum, as represented by lower relative root mean square error (RRMSE) values against actual spectra. It is demonstrated that the PRISMA and AVIRIS-NG canopy spectra are more effectively simulated using their respective biome-specific BSM parameter regimes, with RRMSE improvements from 14.56% to 13.91% and from 13.64% to 10.71% for two tested images captured with these sensors.Item Evaluating scenario based performance of DSSAT response to soil depth, initial soil water content and choice of Zea mays L. cultivar selection in semi-arid North West Province in South Africa(2026-03) Rankin, Christopher J; Lumsden, Trevor G; Nangombe, SS; Landman, W; Beraki, A; Mateyisi, Mohau JProcess-based crop models are widely used to assess crop responses to climate variability, yet their performance is highly sensitive to assumptions regarding soil properties, initial soil water content and cultivar selection, particularly in spatially heterogeneous, rainfed systems. This study evaluates the performance of the DSSAT-CERES-Maize model across the North West Province of South Africa using a fine-scale, quinary catchment-based framework. Four scenario simulations were developed to examine the influence of soil depth, pre-season soil moisture and cultivar choice on simulated maize yields. Model outputs were evaluated against district-level reported yields for the 1981–1999 period using a comprehensive multi-criteria assessment framework incorporating distributional tests, correlation analysis, weighted regression and multiple performance metrics. Results indicate that DSSAT effectively reproduces inter-annual yield variability across spatial scales, with stronger agreement at the district level than at the provincial scale. Scenario performance was highly sensitive to soil depth and initial soil water assumptions, with the scenario incorporating deeper effective rooting depth and intermediate pre-season soil moisture consistently achieving superior agreement across most evaluation criteria. Cultivar selection influenced yield variability, highlighting the importance of representative genetic parameterisation in regional applications. While simulated and reported yield medians did not differ significantly at the district scale, error magnitudes and efficiency metrics varied spatially, reflecting the dominant influence of climate variability under rainfed conditions. These findings demonstrate that spatially explicit, scenario-based evaluation enhances confidence in crop model applications and provides valuable insights for agrometeorological assessments, climate adaptation planning and decision support in semi-arid, water-limited agricultural systems.Item Assessing the influence of solid waste knowledge and concern on pro-environmental action in South Africa: Implications for waste management and circular economy strategies(2026-10) Haywood, Lorren K; Dunn, S; Oelofse, Suzanna HH; Roberts, BJThis study investigates public awareness, concern, personal pro-environmental norms, and household recycling behaviour in South Africa using data from the 2022 and 2024 rounds of the South African Social Attitudes Survey. The findings indicate that recycling behaviour remains limited, with approximately 30% reporting that they “always” or “often” recycle. Regression analyses show that environmental knowledge and waste-specific concern are positively associated with recycling behaviour, although these relationships explain only a modest proportion of the variation in behaviour. Environmental knowledge shows a relatively stronger association, while concern plays a more limited role once knowledge is accounted for, suggesting that awareness of recycling is an important, but not sufficient, influence on action. The association between personal pro-environmental norms and recycling behaviour is weak and inconsistent across survey years, indicating a context-dependent role. The results highlight a persistent gap between environmental awareness and consistent pro-environmental behaviour. In the South African context, this gap is shaped not only by behavioural factors but also by structural constraints, including uneven access to waste collection services, variability in municipal infrastructure, and differences in service delivery capacity across municipalities. The findings provide support for the Theory of Planned Behaviour and Value-Belief-Norm frameworks, while also showing that psychological drivers such as knowledge, concern, and norms are mediated by real-world conditions that influence perceived behavioural control and the translation of environmental values into action. Improving recycling outcomes in South Africa requires an integrated approach that combines behavioural interventions, such as strengthening environmental literacy and reinforcing pro-environmental norms, with systemic improvements in waste management infrastructure and service delivery.Item Mechanical property comparison of AISI 5120 steel produced by LENS and DMD systems(2026-06) Sibisi, TH; Mathoho, Ipfi; Shongwe, BS; Tshabalala, Lerato C; Skhosane, Besabakhe S; Motau, R; Mndebele, N; Vithi, NThis study presents a comparative investigation of the microstructure and mechanical properties of AISI 5120 low-alloy steel fabricated using two Directed Energy Deposition (DED) systems: Laser Engineered Net Shaping (LENS) and robotic Direct Metal Deposition (DMD). The objective was to evaluate process–structure–property relationships under optimized operating conditions representative of each system. Microstructural characterization was performed using optical microscopy and scanning electron microscopy (SEM), while tensile strength, microhardness, and Charpy impact toughness were evaluated according to ASTM standards. The LENS-fabricated samples exhibited a predominantly ferrite–pearlite microstructure and demonstrated higher surface hardness (217 HV) and superior impact energy (137 J). In contrast, the DMD specimens displayed refined microstructural features with bainitic-like characteristics inferred from SEM morphology and achieved significantly higher tensile properties, including an ultimate tensile strength of 754.3 MPa, yield strength of 675.97 MPa, and elongation of 17.63%. Fractographic analysis indicated ductile failure modes in both systems; however, LENS samples showed a higher qualitative presence of porosity. The improved tensile performance of the DMD system is attributed primarily to reduced porosity and enhanced interlayer bonding resulting from higher energy input and improved melt pool stability. While LENS provided enhanced surface hardness and impact resistance, DMD demonstrated superior overall mechanical integrity. The findings highlight the importance of system-level process optimization when selecting DED platforms for load-bearing or wear-critical industrial applications. Further investigation including fatigue testing, quantitative porosity analysis, and phase confirmation using diffraction techniques is recommended.