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Welcome to ResearchSpace, the institutional repository of the CSIR. ResearchSpace is an open access electronic archive collecting, preserving and distributing scholarly digital materials created by the CSIR.

Recent Submissions

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Characterising the spatio-temporal patterns of water quality parameters in the cradle of humankind world heritage site using Sentinel-2 and random forest regressor

(2025-07) Ngamile, S; Kganyago, M; Madonsela, Sabelo; Mvandaba, Vuyelwa

Introduction: Water quality assessment is essential for monitoring and managing freshwater resources, particularly in ecologically and culturally significant areas like the Cradle of Humankind World Heritage Site (COHWHS). This study aimed to predict and map the spatio-temporal patterns of both optically and non-optically active water quality parameters within small inland water bodies located in the COHWHS. Methods: High-resolution Sentinel-2 Multispectral Instrument (MSI) satellite data and two random forest models (Model 1 [consisting of sensitive spectral bands] and Model 2 [consisting of spectral bands + indices]) were used alongside In-situ measurements of chlorophyll-a, suspended solids, dissolved oxygen (DO), pH, Temperature, and electrical conductivity (EC) were integrated to establish empirical relationships and assess spatial variability across high-flow and low-flow conditions. Results: The results indicated that DO could be predicted with the highest accuracy under low-flow conditions, followed by EC. Specifically, Model 2 achieved an R2 of 0.88 and an RMSE of 1.37 for DO, while Model 1 achieved an R2 of 0.63 and an RMSE of 291.48 for EC. For optically active parameters, suspended solids showed the highest prediction accuracy under high-flow conditions using Model 2 (R2p = 0.55; RMSE = 118.19). Due to the over-pixelation of other smaller water bodies within the COHWHS in Sentinel-2 imagery, Cradlemoon Lake was selected to show distinct seasonal (high- and low-flow) and spatial variations in optically and non-optically active water quality parameters. Discussion: Variations in the results were influenced by runoff dynamics and upstream pollution: lower Temperatures and suspended solids under low-flow conditions increased DO concentrations, whereas higher suspended solid concentrations under high-flow conditions likely reduced light penetration, resulting in lower spectral reflectance and chlorophyll-a levels. These findings highlight the potential of Sentinel-2 MSI data and machine learning models for monitoring dynamic water quality variations in freshwater ecosystems.

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The effect of fiber parameters and surface treatment in caster fiber- reinforced polyester composites

(2025-03) Nijandhan, K; Muralikannan, R; Thimiri Govindaraj, Deepak B; Pradeesh, EL

This investigation focused on identifying the effect of fiber parameters (fiber length, fiber weight) on the mechanical properties of pretreated caster fiber-reinforced polyester composites. The composite plates were fabricated using the hand layup technique by varying the fiber length and fiber content in polyester matrix composites. The tensile, flexural, and impact tests were conducted as per ASTM standards. Fracture mechanism was analyzed using scanning electron microscopy (SEM) images. It is found that the highest tensile (20.8 MPa), flexural (46.4 MPa), and impact (38.2 kJ/m2) strengths of composites with 30 mm fiber length and 40% fiber wt. content. The regression equation was formulated and optimum fiber parameters for better mechanical properties were identified using response surface methodology and pattern search optimization algorithm. This study confirms that caster fiber-reinforced polyester composites were used to lightweight engineering applications.

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Agile local manufacturing of active pharmaceutical ingredients in Africa could improve health security and economic growth

(2025-08) Sagandira, Cloudius R

After decades of dependence on imported Active Pharmaceutical Ingredients (APIs) and multilateral aid, Africa faces a critical turning point, seeking to assert control over its health and economic future. Here we discuss how agile local API manufacturing offers a strategic solution to enhance health and economic security, transforming Africa’s pharmaceutical landscape for sustainable medicine access.

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An Investigation into secure, remote, firmware updating mechanisms for peer-to-peer transactive microgrids

(2025-07) Smith, Andrew C; Ledwaba, Lehlogonolo P

Renewable energy-based microgrid deployments are being identified as potential solutions for faster electrification in developing countries. IoT-enabled microgrids solve the physical infrastructure limitations of connecting communities that are geographically distant from main grid energy supply networks and reduce the added demand placed on the already grid. However, with the deployment of long-term, long-lived IoT technologies, a need for appropriate maintenance and updating strategies is introduced to ensure that the network’s security, integrity, and availability is maintained. Hardware would need to access up-to-date features and patches deployed within newer f irmware iterations without significant interaction and effort from the end user. This work aims to identify, evaluate, and recommend appropriate strategies and solutions for remote IoT firmware updating to be used within transactive microgrid deployments. The solutions considered should be able to maintain the security and integrity of the firmware file during distribution and be able to tolerate the unpredictability of transmission utilizing various communications networks and differing levels of network coverage. The investigation compares and analyses various firmware updating methodologies for lightweight operation, capability of minimising the monetary cost of firmware updating to the end user, and coverage of firmware updating attack vectors As part of future work, the identified firmware mechanisms shall be implemented within a demonstrable microgrid network simulation to assess the performance and latency impacts introduced on microgrid transactions and IoT network processes.

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Librarians to the Rescue! An LIS-Associated Workflow Model for the Rescue of Research Data at Risk

(2025) Patterton, Louise H; Bothma, Theo JD; Van Deventer, Martie J

This study presents a data rescue workflow model and explores the potential roles and responsibilities of the library and information services (LIS) sector in rescuing at-risk data. The methodology was multifaceted, consisting of three distinct phases of data collection and analysis. First, content analysis was conducted on 15 purposively selected data rescue publications to identify key activities that are integral to the data rescue process. This phase resulted in the creation of an initial data rescue workflow model. Second, feedback was obtained from six experienced researchers at a South African research institute, chosen from a sample of criterion-based researchers, after they reviewed the initial model. This feedback was used to revise the model. Third, additional feedback on both the initial and revised models was gathered during a mini focus group session with three purposively selected LIS experts at the same research institute. This feedback was used to refine the model and develop a final recommended data rescue workflow model, which is presented in this study. The recommended model outlines the crucial stages, activities, and outputs of data rescue in a chronological sequence. The study’s outcomes provide new insights into data rescue and the involvement of LIS professionals, highlighting how various LIS experts can contribute to data rescue projects.