School of Engineering

The potential of epoxy coated chicken feathers as modified natural fiber in concrete

2026-06-24T16:33:23Z

The potential of epoxy coated chicken feathers as modified natural fiber in concrete Rikhotso, Mixo Asset This study assessed the viability of incorporating both untreated (UCF) and treated chicken feathers (TCF) into concrete to enhance sustainability in the construction industry. Five concrete mixes were tested, with Mix 4 (0.75% TCF) and Mix 5 (1.25% TCF) emerging as the most promising. These mixes showed improved workability and retained high compressive and tensile strength compared to the control. In contrast, the mix with 1% UCF exhibited significant reductions in mechanical and durability performance. Durability tests confirmed that TCF-enhanced concrete maintained resistance to oxygen permeability, water absorption, and chloride penetration, while also displaying reduced shrinkage. Overall, treated feathers proved to be a suitable partial replacement in non-structural concrete applications, offering both environmental and engineering benefits. Text and abstract in English

Geotechnical analysis of dolomitic terrain to assess the probability of sinkhole formation : a case study of Centurion, South Africa

2026-06-17T10:26:51Z

Geotechnical analysis of dolomitic terrain to assess the probability of sinkhole formation : a case study of Centurion, South Africa Mavhetha, Lavhelesani Dolomitic terrain in the Gauteng Province of South Africa presents significant geotechnical challenges for urban development. This is primarily due to subsurface dissolution processes that create void networks susceptible to sinkhole formation and ground subsidence. This research study explores the case of Cornwall Hill in Centurion where numerous sinkhole incidents have caused infrastructure damage and imposed severe development constraints. A multi-method investigation approach was employed, combining gravity geophysical surveys, test pit excavations, rotary percussion boreholes, dynamic cone penetrometer tests, and laboratory analysis. Gravity surveys comprised 105 measurement stations on a 50 m × 50 m grid. Five test pits were excavated while four rotary percussion boreholes were drilled to depths between 10 and 25 m. Five dynamic cone penetrometer tests were also carried out on site and rotary percussion drilling was done to complement gravity surveys. Lastly, a comprehensive laboratory geotechnical analysis programme was done on field samples collected on site. Results revealed that the site is underlain by Malmani Subgroup dolomites overlain by a consistent three-layer stratigraphic sequence comprising colluvium, residual soil, and dolomite bedrock. The residual soils exhibited consistent classification as low plasticity clay with plasticity indices of 11 – 14% and a gravel-rich composition at 50 – 60%. However, the soils displayed significant spatial variability in thickness (0.70 – 2.70 m) and bearing capacity (152 – 320 kPa at 0.7 – 0.8 m depth). Rotary percussion drilling confirmed the presence of shallow competent dolomite beneath chert layers at 2 m depth and colluvium overlying interbedded chert and dolomite from 3 m depth. A cavity located within the peripheral low-density gravity zone and extending from 2 m to 13 m depth before competent material was also reached. Gravity survey results defined the subsurface density contrast, with high-density areas (covering 60% of the site) indicating shallow competent bedrock at 1.0–1.6 m depth and low-density areas (covering 40% of the site) indicating deep weathering profiles exceeding 2.7 m; the cavity intersected in BH01 directly correlates with low gravity in the peripheral zone. The site was described into Zone A (central D3 area of the site suitable for development with raft foundations at 600–900 mm depth) and Zone B (peripheral D4 area of the site unsuitable for development owing to the presence of a cavity, gravity lows indicating solution features, and high collapse potential) based on the results of integrated geophysical, intrusive, and laboratory investigation. The study meets the requirements of SANS 1936-2:2012 and proves the potential of integrated characterization of complex terrain, including the application of Rotary Percussion Drilling (RPD) as ground truth, for making informed decisions regarding development of difficult terrain such as this dolomitic environment, while providing valuable geotechnical data for the Centurion region.

Design optimisation and development of a pneumatic prosthetic foot

2026-05-29T10:54:45Z

Design optimisation and development of a pneumatic prosthetic foot Godlimpi, Zanodumo Thandazani Lower-limb amputation is a life-saving and life-changing surgery that significantly impacts mobility and quality of life, particularly in South Africa, where access to advanced prosthetic technology is hindered by socio-economic factors and infrastructure challenges. Prosthetic feet are classified into three distinguishable categories: conventional feet, which include solid ankle cushion heel and articulated prosthetic feet, energy storage and release feet and bionic feet. Conventional passive prosthetics, such as the SACH foot, often fall short in replicating the normal walking dynamics, leading to asymmetries when walking and increased energy cost of walking. This study piloted a pneumatic prosthetic foot to investigate the biomechanical benefits of using this innovation while walking at self-selected walking speed over flat surfaces. The study utilized a quantitative (experimental) research method, commencing with the Finite Element Analysis (FEA), using the ANSYS software to simulate axial structural loads during standing positions on titanium and aluminum alloy shank segments. A prototype was developed featuring a crank-slider mechanism and a pneumatic cylinder to modulate ankle stiffness. Clinical evaluation involved a case study of two transtibial participants. Walking gait was analysed using the Templo markerless motion capture system (Theia3D) across three conditions: the prescribed passive prosthetic foot, an unpressurized version of the pneumatic prosthetic foot, and a pressurized version of the pneumatic prosthetic foot (4 bars). Spatiotemporal parameters, kinetics, and kinematics, including stride length, cadence, and vertical ground reaction forces (vGRF), were systematically recorded and analyzed across varying conditions. A stark contrast between participants was revealed by the study findings, participant 1 demonstrating improvements in walking symmetry (spatiotemporal parameters and kinetics), while participant 2 demonstrated minimal benefit when using the pneumatic prosthetic foot. The study findings suggest that device performance, one way or another, was influenced by the user adaptation and biomechanical conditions of the participant. The preliminary findings align with the broader body of literature, suggesting that semi-active prosthetic devices can bridge the gap between expensive powered devices and passive prosthetics. On the contrary, the pneumatic prosthetic foot was not practically lighter than other powered prosthetic devices. This research developed a functional pneumatic prosthetic prototype that can withstand the axial loading of the human body, and can be used for mobility. Though the pneumatic prosthetic prototype has demonstrated potential, the findings need to be interpreted with caution due to the small sample size (n=2), which limits the generalizability of the findings. The current pneumatic prosthetic foot prototype requires further refinements to reduce both the mass and the height of this prosthetic foot. Also, improvements in the control system are required to modulate the ankle stiffness during walking. Additionally, the system faced challenges in replicating passive shock absorption during the load acceptance phase in the early stance. Future research should include large and diverse participant cohorts, and longitudinal studies to monitor neuromuscular adaptation and changes in the walking dynamics. Text and abstract in English

Characterisation of innovation and implementation rates across a South African mining organisation

2026-05-19T10:10:36Z

Characterisation of innovation and implementation rates across a South African mining organisation Schoonbee, A. J. D. The aim of this study was to measure shopfloor participation in a corporate innovation program within a South African mining operation. Employees were categorised according to age, gender, years of service, and job grading. The rate of innovation response was measured and analysed in terms of the type of innovation as well as the trajectory. During the first 12 months of the program, from September 2023 to August 2024, a total of 1005 submissions were registered, with 826 (82%) conforming to the criteria set for the program. Sufficient data was obtained through which each of the five (5) research questions could be answered. The 35-45 years age group had the highest level of representation in the program at 26% of the category. A slight bias of female participants over males was noted. The >15 to <= 20 years of service category had the highest level of representation in the program, at 32%. Three Paterson grading categories contributed most to the program: Upper C (Specialists and Supervisors), Lower D (Superintendents), and Upper D (Managers), while B Band employees (unskilled & semi-skilled) reflected lower response rates. Demographic groupings that were relatively under-represented included <25 years age group, the <=5 and >20 years of service categories, as well as the contractor, student and B-band job gradings. Approximately one in ten ideas registered during the period were implemented, showing that ideation exceeded the capacity to implement. ‘Incremental’ innovation was the dominant type, representing 94.9% ahead of ‘disruptive’ innovation at 4.3%. In terms of trajectory, most innovations (i.e., 76%) were aimed at the ‘internal’ work environment, with the ‘production’ environment at 22% as the second highest domain. Return on innovation investment (ROII) was considered in terms of both tangible / commercial and intangible / soft benefits. The program delivered sixteen innovations with tangible financial returns of more than R100,000, while thirteen of these innovations had a return on investment above R1 million, and three had a return of over R10 million measured per calendar year. An analysis of intangible value addition by category showed that ‘operational approach’ was the most frequent intangible benefit at 38.5%, followed by ‘safety and health’ at 28.2%, and ‘maintenance approach’ at 17.0%.