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Item Acoustic device for recording and tracking rock hazards on the mining face(2024-09) Greeff, Heinrich; Pienaar, M; Hanekom, Johan WLTo enhance personnel safety and operational efficiency in underground mining, this project introduces an innovative acoustic device for recording and tracking rock hazards on the mining face. This system combines advanced acoustic analysis with an ultra-wideband (UWB) location system to interpret sounds produced during rock mass sounding and scaling. The location system is georeferenced to the mine’s local coordinate system using available survey pegs. By integrating these technologies, each acoustic data point includes a spatial XYZ coordinate which facilitates tracking of loose rock locations throughout the mining excavation process. This dual-sensory approach advances previous methods by leveraging the innovation of acoustic technology and tailoring algorithms to specific rock types, enhanced by the tracking function so that rock hazards encountered underground can be mapped and communicated to the operational team. The collected data offers a systematic approach to hazard identification and enhances mine designs and operational strategies by providing insights into the dynamic response of the rock mass during excavation under different mining conditions. This project offers a new approach to proactive hazard management, potentially transforming how mines are operated and mine designs monitored to ensure safety and efficiency.Item On the existence of a family of ideal aircraft configurations(2024-09) Huyssen, Reinhard J; Spedding, GRThe bulk of fossil fuel in aviation is consumed in the domain of fixed-wing subsonic flight. Environmental concerns put strong incentives on the industry to improve flight efficiency. Best flight efficiency can only be attained if an aircraft design is based on its ideal configuration. Already since the middle of the previous century, the industry became entrenched in the tube-and-wings configuration, here referred to as the Current Dominant Configuration (CDC). It is widely speculated that better arrangements of wings and bodies exist, and many research initiatives are dedicated to the exploration of alternatives. These are typically done for specific types of aircraft, mostly for the airline industry. Yet, new aircraft developments keep employing the CDC as if proposed alternatives are ignored. Here a hypothesis is tested which suggests that a single family of aircraft configurations exists which is ideal for the majority of economically significant flight objectives within this domain. To organise the aircraft design space into families of configurations, a hypothetical Ideal Wing is introduced as a common basis from which all configurations evolve by inflation to provide practical flyers with volume for their payload. While the most prominent configurations, including the CDC, appear to disqualify as candidates for the proposed ideal configuration, the one which qualifies, has not been seriously examined in human aviation, although it is familiar. Termed the Natural Dominant Configuration, as it appears in natural flyers, it certainly merits further exploration.Item Assessing the nanomechanical, wear and thermal stability of Ti-Al-Si-V alloys produced via laser engineered net shaping (LENS) in-situ alloying(2024-12) Raji, SA; Popoola, API; Pityana, Sisa L; Tlotleng, MonnammeTitanium aluminide (TiAl) intermetallic alloys are highly recognized because of their lightweight qualities and are particularly useful for replacing heavier Nickel-based (Ni-based) superalloys in high- temperature components. This study fossed on the investigation of the nanomechanical, wear, and thermal stability of intermetallic Ti-Al-Si-V alloys fabricated by in situ alloying with elemental metal powders using the laser engineered net shaping (LENS) technology. The impact of Vanadium (V) feed rate was examined both before and during the annealing heat treatment, which involved 60mins at temperatures of 1200 and 1400°C, and furnace cooling (FC) conditions. After heat treatment (1200°C and 1400°C), it was discovered that V addition enhances the Ti-Al-Si-V alloy's nanomechanical properties. According to the nanoindentation results, the mechanical characteristics of the heat-treated samples were typically better than those of the as-deposited alloy and were equivalent to the qualities of commercially available TiAl alloys. The alloy that was heat-treated at a temperature of 1200°C exhibited better tribological and thermal stability. Lastly, the as-deposited sample performed better in terms of tribological and thermal stability aspects than the sample that was heat-treated at 1400°C.Item The use of amino acids in gold leaching; the FTIR and DFT approach(2024-09) Tapfuma, A; Akdogan, G; Luckay, RC; Lopis, Anton SThe drive towards environmentally benign gold mining, often referred to as ‘green mining’, has gained momentum as a response to the escalating environmental concerns linked to cyanide usage in gold processing. Recently, amino acids have emerged as promising gold-leaching lixiviants, offering advantages over the conventional cyanide methods. However, the bulk of research has predominantly focused on glycine, the first member of the alpha-amino acid group, leaving other amino acids unresearched. In a novel approach, this study shifts the focus to the use of alanine in gold leaching and associated gold-alanine complexation at both experimental and computational levels, coupled with dissolution work. Experimental analyses through Fourier Transform Infrared Spectroscopy (FTIR) showed that alanine, in either its neutral or deprotonated state, effectively bonds with gold through donor electrons from nitrogen (N) and oxygen (O) at the amine and carboxylic end, respectively. In addition, the complexes of deprotonated alanine, compared to neutral (zwitterion) alanine, exhibited higher characteristic peak shifts during complexation. Furthermore, quantum computational calculations revealed that deprotonated alanine formed the most stable gold complex compared to the neutral amino acid, characterized by the N-Au-N bonding. The complexation of gold and deprotonated alanine exhibits the larger complexation energy compared to the neutral form, as revealed by the computational analyses. The third part of the study involved the dissolution of gold using both the deprotonated and neutral molecules, and the results showed that gold dissolution was more pronounced using the deprotonated molecule. This study showed that the gold dissolution is connected to the complexation as shown by FTIR and DFT, and this can be seen in high gold dissolution corresponding to a high peak shift at deprotonation pH and high complexation energy for the gold with the deprotonated alanine compared to the neutral alanine. Lastly, the study suggests that deprotonated alanine can be a possible lixiviant to leach gold from secondary gold sources such as tailings.Item A government sustainable building rating tool?(2024-07) Gibberd, Jeremy TSome countries have significant public building backlogs. Schools, colleges, clinics, and hospitals still need to be built and existing infrastructure needs to be updated and refurbished. In addressing backlogs, there is the prospect of developing more sustainable buildings and infrastructure. However, often this opportunity is not taken, and the design and construction of public buildings continue to follow conventional unsustainable approaches. Reasons for this include the lack of a suitable sustainable building rating tool that aligns with government priorities. To address this gap, this study explores development a Government Sustainable Building Rating Tool (GSBRT). It investigates this for South Africa, a country with large public building backlogs. Government policy is analysed to establish the key development priorities and translate these into building performance criteria. These criteria are compared with criteria from an existing green building rating tool, to determine alignment. The study finds that while there is some overlap, there are also significant differences and that the conventional green building rating tool does not cater for some government sustainable development priorities. Recommendations are made for further research and development of a GSBRT as a means of addressing sustainability in government buildings.Item Effects of heat treatment on the properties of arc melted AlCuFeNiSi0.4 and AlCuFeNiTi0.2 high entropy alloys for engineering applications(2024-12) Adeyoye, A; Popoola, P; Mathe, Ntombizodwa R; Popoola, O; Dada, M; Dhliwayo, NIn this study, AlCuFeNiSi0.4 and AlCuFeNiTi0.2 high entropy alloys (HEAs) were synthesized using arc melting. The as-cast alloys were heat treated at 750 °C for 4hrs then quenched in water and oil and aged for 6hrs to examine the influence of the quenching media (water and oil) on the microstructural, nanomechanical, corrosion and wear characteristics of the alloys. The XRD results revealed that both alloys had BCC phase and FCC phase structures, where Ti and Al were the BCC stabilizers and Cu and Ni acted as FCC stabilizers. The excellent combination of hardness and elastic modulus of both alloys quenched in water shows that ageing can improve the properties of the alloys. The alloys quenched in water after ageing offered improved properties compared to those quenched in oil for both alloys. The wear resistance was higher in AlCuFeNiSi0.4 than inAlCuFeNiTi0.2 attributed to the strengthening mechanism of the alloy. Electrochemical tests also showed that the AlCuFeNiSi0.4 alloy composition was more corrosion resistant and easier to passivate in 3.5% NaCl. The combined action of the elements in the HEA composition produced surface oxide layers that were more stable and resistant to corrosion. Hence, the heated treated Si0.4 HEA derivative has the potential to be used as materials in wider corrosive environments in the energy industry.Item Flutter clearance techniques and tools for gliders(2024-08) Van Zyl, Louwrens HThe flutter clearance of gliders pose some special challenges. Modal frequencies are low, making suspension of the glider for ground vibration testing challenging. The low frequencies also make large amplitudes of excitation desirable. In flutter flight testing space for excitation systems and telemetry systems is limited.Item Extracting and categorising the reactions to COVID-19 by the South African public - A social media study(2021-09) Marivate, V; Moodley, AvashlinSocial Media can be used to extract discussion topics during a disaster. With the COVID-19 pandemic impact on South Africa, we need to understand how the law and regulation promulgated by the government in response to the pandemic contrasts with discussion topics social media users have been engaging in. In this work, we expand on traditional media analysis by using Social Media discussions driven by or directed to South African government officials. We find topics that are similar as well as different in some cases. The findings can inform further study into social media during disaster settings in South Africa and beyond. This paper sets a framework for future analysis in understanding the opinions of the public during a pandemic and how these opinions can be distilled [in a semi-automated approach] to inform government communication in the future.Item Infrastructure in human settlements in South Africa(2024-07) Gibberd, JeremyThe purpose of this paper is to present research that develops and tests human settlement infrastructure policy statements as input for a new White Paper on Human Settlements in South Africa. The study develops infrastructure policy statements for human settlements. These are tested through an online survey of human settlement stakeholders. Data gathered through the survey are analysed to provide findings for the study and recommendations for human settlement policy development. The findings indicate that addressing infrastructure in human settlements in South Africa is a high priority. It shows that there is strong support for alternative delivery and operational models, increased involvement of the private sector and communities, innovative financing and the use of sustainable technologies and systems, in the development and operation of infrastructure in human settlements. The study is original as it explores new approaches to addressing infrastructure backlogs in human settlements in South Africa. It contributes new thinking on how the private sector and communities can be involved, alternative delivery models developed, and how sustainable technologies may be applied in addressing these backlogs.Item Microstructure and mechanical properties study of Ti-12Mo alloy for biomedical applications(2024-07) Raganya, Mampai L; Moshokoa, N; Obadele, B; Machaka, Ronald; Makhatha, EThe aim of the work was to study the microstructural characteristics and mechanical properties of Ti-10Mo and Ti-12Mo alloys. The stability of the β phase was predicted using the molybdenum equivalence, average electron concentration ratio, and d-electron approaches. Microstructural examination was conducted using scanning electron microscopy and electron backscatter diffraction, while phase analysis was performed by x-ray diffraction. Uniaxial tensile test machine was employed to conduct tensile tests. The microstructure of Ti-12Mo alloy revealed primary BCC beta (β) phase and some nanoparticles of martensitic α" phase and hexagonal omega (ω) phase precipitated in the β matrix. The precipitation hardening of the ω phase resulted in superior microhardness, tensile and yield strengths. Contrarily, the existence of the ω phase contributed to the brittle fracture that occurred during tensile tests, a higher elastic modulus and lower elastic admissible strain than those of the human bone. Nonetheless, the characteristics and mechanical properties observed of the studied β-type alloy qualify it as a promising candidate for biomedical applications.Item Rule-based spectrum allocation algorithms for heterogeneous cognitive radio wireless networks(2024-11) Masonta, Moshe TThe growing number of heterogeneous cognitive radio wireless network (CRWN) deployments sharing the same radio frequency spectrum band will lead to a number of new coexistence challenges when it comes to channel allocation. In this paper we propose rule-based spectrum allocation algorithms for CRWN. In the channel partitioning (CP) rule, white space (WS) channels with the biggest bandwidth are partitioned to the required bandwidth sizes before being allocated to a CRWN that requires smaller bandwidths. In the channel bonding (CB) rule, a number of WS channels are bonded together to meet the needs of the CRWNs requiring the widest bandwidth. Performance evaluation results show that the total number of WS channels allocated under rule-based scheme was equivalent to those allocated under an interference aware WS allocation scheme. However, in order to satisfy quality of service of secondary users, the rule-based scheme searches for the most suitable WS channels among the list of discovered channels through partitioning rules.Item Bootstrapping syntactic resources from isiZulu to Siswati(2024-05) Marais, Laurette; Pretorius, L; Posthumus, LCIsiZulu and Siswati are mutually intelligible languages that are considered under-resourced despite their status as official languages. Even so, the available digital and computational language resources for isiZulu significantly outstrip those for Siswati, such that it is worth investigating to what degree bootstrapping approaches can be leveraged to develop resources for Siswati. In this paper, we present the development of a computational grammar and parallel treebank, based on parallel linguistic descriptions of the two languages.Item Applying phonological feature embeddings for cross-lingual transfer in text-to-speech(2024-07) Louw, Johannes A; Wang, ZIn this work, we build upon our previous research where we introduced phonological features as input to text-to-speech systems. While the use of phonological features is not a novel concept in our research, our focus in this study is on the comprehensive analysis of the embeddings produced by the encoder model, which we believe offers novel insights into the model’s ability to capture and generalize phonological patterns across languages. Cross-lingual transfer experiments are conducted using both a resource-rich and a resource-constrained language to explore the model’s cross-lingual transfer capabilities across different linguistic families. The analysis of the embedding vectors produced by the encoder model is conducted using cluster maps to visualize the hierarchical clusters obtained using a clustering procedure. This analysis reveals the model’s learning patterns and provides insights into how phonological features contribute to the model’s ability to handle linguistic diversity and data scarcity.Item Review of a full-polarimetric calibration target for radar cross section measurements(2018-11) Blaauw, Ciara; Cilliers, Jacques E; Potgieter, MoniqueThis research investigated the feasibility of a passive calibration target to calibrate a fully-polarimetric bistatic Cband radar. A screw-like target, found in open literature, was utilized as it produced relatively high co- and cross-polarized radar cross section (RCS) returns. In this study the required elevation alignment accuracy of the receiver, relative to the transmitter-target plane, to produce good calibration results was also investigated. The target was slightly modified to possibly improve the elevation beam-width and peak RCS.Item iSinkwe: An application that synchronises text and audio for enhanced reading(2024-03) Kruger, Rynhardt P; Govender, Avashna; Van der Walt, Willem J; Wilken, IlanaWe present iSinkwe, a system to produce synchronised accessible EPUB 3 books of text and audio. With iSinkwe, users are able to synchronise EPUB 3 publications with human-narrated or computer-generated speech, via an accessible web interface. Documents in other formats can also be converted to EPUB 3. Developed specifically to address reading barriers experienced by users with print disabilities such as dyslexia and visual impairment, iSinkwe is also of particular importance for regions with low literacy such as South Africa. This paper describes the motivation and context for its creation, the components that make up iSinkwe, a discussion on the relevance it has for the accessibility community, and how users can interact with the system. A usability study was performed on a previous iteration of iSinkwe, with mixed results. We report on the lessons we learned, and subsequent improvements to the system. Finally, we describe future work planned to extend its functionality.Item MarCOSIO: Supporting coral bleaching monitoring in the Western Indian Ocean(2024-05) Smith, Marie E; Mbugua, JMarCOSIO is one of 2 marine consortia within the GMES&Africa programme and this project is lead by the CSIR (South Africa). The project represents 12 partners in 8 countries in Southern Africa and the Western Indian Ocean (WIO) region, and supports coral bleaching monitoring in the Western Indian Ocean.Item Accelerating the use of mobile phone capabilities to maximise the effectiveness of public emergency alerts in South Africa(2024-10) Mukange, Tsumbedzo; Mokoto, Bayanda T; Moipolai, Tumelo B; Ndamase, ZimasaAn emergency alert system (EAS) enables government authorities, its agencies, and community authorities at various levels to use communication platforms to inform people in threatened areas of imminent disaster. Disseminating emergency alerts to the public is crucial to ensure effective and efficient disaster management. The purpose of disseminating emergency alerts is to provide important and life-saving information to the public so they can take the necessary actions to ensure their safety. EAS uses various communication channels to disseminate alerts and warnings, including TVand radio, sirens and long-range acoustic devices, message signage and public address systems, the Internet, fixed phones, and mobile phones through cell broadcast services (CBS), SMS and mobile apps. The United Nations launched the Early Warning for All initiative that promotes the use of geo-located mobile-based early warning services, such as CBS and location-based SMS (LB SMS), to disseminate emergency alerts to all by 2027. The accessibility of mobile phones has accelerated the use of mobile phone capabilities to disseminate emergency alerts. In South Africa, using CBS and LB SMS capabilities to disseminate emergency information to targeted geographical areas by authorities is still an area of improvement. T hestudy aims to accelerate the adoption and use of cell broadcast and location-based SMS to maximize the effectiveness of public emergency alerts in South Africa. The study forms a basis to accelerate the adoption and use of CBSandLBSMStodisseminatepublic emergency alerts. Partial results show emergency alert message crafting and appropriate communication approaches are vital in influencing the public to comply with the alert. In addition, South Africa had implemented some components of emergency alert systems, but in isolation and focusing on specific types of emergency alerts.Item Towards a 5G equipped video surveillance UAV for public safety(2024-05) Makhalanyane, Thapelo; Mamushiane, Lusani; Kobo, Hlabishi I; Lysko, Albert ASouth Africa faces a severe crime problem, with persistent issues such as murder, hijacking, and CIT heists. This research examines existing surveillance strategies, including UAVs, and identifies their limitations. To address these shortcomings, we propose a novel solution that leverages 5G technology to enhance UAV capabilities, offering low latency and high bandwidth for improved surveillance. Our solution introduces a hybrid-VTOL surveillance UAV integrated with predictive policing techniques. Machine learning algorithms and statistical analysis will be employed to forecast crime-prone areas, enabling strategic UAV deployment. We will develop and evaluate this solution utilizing a CSIR-developed 5G testbed, focusing on Quality of Service (QoS) metrics. A UAV equipped with a 4K camera will act as User Equipment (UE), with functionality assessments carried out from a ground control station (GCS). Key performance indicators like RSRP (Reference Signal Received Power), RSRQ (Reference Signal Received Quality), RSSI (Reference Signal Strength Indicator), packet loss, throughput, and control latency will measure the solution's effectiveness and its potential to make a positive impact on societal safety.Item A review of PFCP cyber attacks in 5G standalone for robotic telesurgery services(2024-10) Makondo, Ntshuxeko; Baloyi, Errol; Kobo, Hlabishi I; Mathonsi, TEThe emergence of fifth-generation technology (5G) has revolutionised telecommunication networks, offering enhanced mobile broadband, ultra-reliable (eMBB), ultra-lowlatency communications (uRLLC), and massive machine-type communication (mMTC) service classes. This breakthrough has garnered significant attention and investment worldwide, driving innovation and growth in the digital era. However, the adoption of cloud-based 5G core (5GC) networks, while offering scalability and deployment flexibility, has posed challenges to meeting stringent latency requirements, particularly for uRLLC services specifically for robotic telesurgery. To address this problem, mobile network operators (MNOs) have turned to edge computing (EC), using the control and user plane separation (CUPS) architecture introduced in the thirdgeneration partnership project (3GPP) release 14 specification. This architecture enables the deployment of the user plane function (UPF) closer to users, reducing latency, and improving quality of service (QoS). However, the deployment of the UPF as a standalone node on the edge of the network exposes the packet forwarding control protocol (PFCP) to cybersecurity attacks, which pose risks to telesurgery services and could even lead to loss of life. In the existing literature, only a few techniques focus on minimising these attacks when the UPF is deployed on the edge of the network far from the 5GC. Therefore, this paper reviews PFCP attacks and explores machine learning (ML) techniques to mitigate these security threats. This paper further provides recommendations and future research directions for mitigating these attacks.Item Flat Plate Flutter in a Supersonic Flow Field(2024-07) Ndebele, Bright BThe interaction of a two-dimensional cantilevered elastic flat plate with a supersonic flow field was investigated numerically using StarCCM+. The plate was 0.4 m in length and inclined at 15∘ to the freestream at three Mach numbers (1.2, 1.35, and 1.45). The flat plate was assumed to be aluminium. Using StarCCM+, the inviscid Navier-Stokes equations were solved, and the fluid-structure interaction resolved. This way, the flow field around the plate and the plate deflection were calculated. The results indicated that at Mach 1.2, the plate exhibited a steadystate deflection, while at the other investigated Mach numbers, limit cycles were observed. The deformation of the plate caused a flow compression at the top, resulting in a weak shock at Mach 1.2 and strong shocks at 1.35 and 1.45. These findings provide insight into the dynamic response of the plate and the corresponding flow characteristics at different Mach numbers.