ResearchSpace

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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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Combustion characteristics of dual swirl low nitrogen burners in small gas boilers

(2025) Xiangyun, L; Zhu, L; LiangDe, L; XiuFang, K; Haitao, Zheng

Swirl combustion technology is an effective method for achieving low-nitrogen (low NOx) combustion. In this study, we designed a dual-swirl low-NOx burner with the goal of minimizing NOx emissions. and the burner was evaluated in a 20t/h gas boiler through numerical simulation and experimentation. Swirl angles and excess air coefficients (1.0 to 1.20) of the burner were tested within the range of 1.0 to 1.2. The results indicated that the optimal swirl plate angles were 35° internally and 55° externally. The optimal excess air coefficient was 1.15, which balances heat transfer efficiency and minimize NOx emissions. Results show that the dual swirl combustion system can effectively reduce nitrogen oxide emissions in small gas boilers.

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Building a low-cost cloud Native 5G network slicing experimental testbed: Open-source solutions, lessons learned and future directions

(2025-11) Otieno, HO; Mamushiane, Lusani; Maurine, C; Mukute, T; Mwangama, J; Malila, B; Modroiu, ER; Magedanz, T

Research on network slicing has gained some ground since its introduction to 5G networking. Network slicing has evolved from ideas, concepts, and simulations to real-world implementations. With this advancement, the realization and experimentation of network slicing remain a challenge due to the complexity involved. Research and experimentation testbeds have been built to explore and advance network slicing. However, most are quite expensive to set up or complicated for the novice researcher exploring 5G network slicing. In this work, we present a comprehensive and repeatable methodology that can be used to realize network slicing. Our approach focuses on building a low-cost, experimental cloud-native testbed using open-source solutions. The testbed leverages containerization and orchestration platforms to deploy the core network. We demonstrate end-to-end network slicing by extending the Open Air Interface’s reference setup with custom Helm charts. We validate the process of the user equipment requesting a slice on the network, to admission and management of the slice using slice-specific identifiers like Slice Service Type and Slice Differentiator. We highlight the lessons learned when automating this testbed setup to ensure the testbed is repeatable, consistent and proper resource isolation is achieved per slice as envisioned in network slicing. This work serves as a practical guide for researchers to experiment with and explore network slicing using readily available off-the-shelf hardware.

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Cross-realm biodiversity profile of the South African coastal zone

(2025-04) Harris, LH; Adams, JB; Dayaram, A; Dunga, LV; Job, N; Kirkman, SP; Lamberth, SJ; Pfaff, MC; Van Deventer, Heidi; Van Niekerk, Lara

South Africa’s coast is 3 113 km long and includes microtidal shores that experience semi-diurnal tides and mostly high wave energy. From west to east, the cool Benguela Current and the warm Agulhas Current drive steep gradients in climate and environmental conditions, resulting in diverse coastal ecosystem types. Here, we review the biodiversity of South Africa’s coastal zone, focusing on the constituent ecosystem types from the terrestrial, freshwater, estuarine and marine realms, and provide a brief overview of cross-realm biodiversity patterns. We also give guidance on coastal boundaries to improve standardisation in this complex area to support assessment, planning and management. The ecologically determined coastal zone currently comprises 193 ecosystem types: 83 vegetation types (e.g. seashore vegetation, strandveld, duneveld, coastal forest); 22 estuary and 3 micro-estuary ecosystem types; and 85 marine ecosystem types (e.g. shores, islands, reefs, kelp forests, bays), with planned inclusion of freshwater types (e.g. coastal lakes, forested wetlands, dune slacks) in the future. Species richness is generally highest along the south and east coasts, with the highest levels of endemism mostly reported for the south coast. The South African coast is a national asset that warrants careful management for long-term sustainability to safeguard its unique biodiversity and many associated benefits for current and future generations.

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Healthy estuaries enhance climate change resilience for fish within South African coastal seascapes

(2026-07) James, NC; Edworthy, C; Van Niekerk, Lara; Lamberth, SJ; Adams, JB; Whitfield, AK; Deyzel, SHP

The capacity for estuaries in coastal seascapes to locally mitigate the effects of regional climate change should be considered in adaptation planning. In this paper we review work undertaken in South Africa’s warm-temperate estuaries to examine factors that promote climate change resilience for estuaries and associated fish and also the potential refuge provided by estuaries from climate change impacts within coastal seascapes. The thermal refuge provided by the middle and upper reaches of permanently open marine dominated estuaries for fish species is illustrated from long-term temperature monitoring in estuaries and adjacent coastlines. During extreme temperature events in the nearshore and lower estuary reaches, minimal thermal variability is maintained in middle and upper estuarine reaches, thus providing biota with a refuge against extreme thermal variability. In healthy estuaries seagrass meadows are particularly important nursery habitats, which have the added ecosystem service of maintaining pH stability and providing ocean acidification refuges for associated fauna. However, this refuge potential (resilience) declined when high water temperatures associated with a marine heat wave, interacting with nutrient enrichment, caused macroalgae blooms in seagrass meadows. We identified estuaries in the warm-temperate region that potentially provide temperature and pH refuge based on their key features (connection to the sea, habitat availability and extent). In the warm-temperate seascape 13 estuaries with marine dominated middle reaches potentially provide thermal refuge for stenohaline species seeking refuge from thermal stress. Extensive seagrass beds potentially providing ocean acidification refuges are found in 10 of these 13 estuaries. Fish communities in healthy refuge estuaries (defined as estuaries with minimal habitat alteration and loss) are more resilient to climate change impacts than those in altered systems, with eutrophication being the primary anthropogenic driver of change.

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Exploring metallic nanoparticles for enhanced multiplexed SERS for diagnostics

(2025-03) Thwala, Nomcebo L; Thobakgale, Setumo L; Mcotshana, Zenande KS; Tlomatsane, Moratoa HC; Ombinda-Lemboumba, Saturnin; Lugongolo, Masixole Y; Mthunzi-Kufa, Patience

When it comes to diagnostics and disease management, while physicians focus on the prognosis and mortality caused by viral diseases, it is necessary to be thorough about metabolic chronic illnesses that could cause complications. Owing to its remarkable sensitivity and capability for multiplexing, Surface-Enhanced Raman Spectroscopy (SERS) emerges as a potent analytical approach with substantial promise in the realms of bioanalysis and diagnostics. This work focuses on exploring metallic nanoparticles that can be used for SERS- based pathogen and metabolic disorder-biomarkers detection for rapid viral infection and chronic disease diagnosis using SARS-CoV-2 or HIV pseudo-virus and a diabetes biomarker, glucose. Herein, metallic nanoparticles (NPs) such as gold (Au) and silver (Ag) nanoparticles, were assessed for their sensitivity in detecting both disease-biomarkers in a buffer containing HIV pseudo-virus and glucose.