Theses and Dissertations (University of Pretoria)

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Model predictive static programming control applied to mineral processing plants
(University of Pretoria, 2023-05) Le Roux, Johan Derik; z.noome@gmail.com; Noome, Zander Meindert
In a mineral processing plant, the separation of valuable material from ore has multiple stages. Usually, the ore is crushed or ground into smaller parts through multiple crushers or grinding mills. This is called the communition process. This process is typically the first stage for extracting valuable material and is important for further down-stream processes. The output of the communintion stage is usually regulated to achieve a stable throughput and a specific ore particle size. After the ore is crushed and ground to a specified size, the valuable material in the ore needs to be separated from the undesired materials. The properties of the desired material influence the method used for separation. These methods include froth flotation, gravitational separation, magnetic separation and electrostatic separation. The separation process can include multiple process streams to get a high grade of the desired minerals out of the ore. In froth flotation, the main objective is to extract the desired material from the ore to obtain a large mineral recovery. Because the flotation process relies on the flotation of particles, particle size is extremely important. The use of control systems in mineral processing plants has been adopted to improve throughput, optimize power usage, ensure safe process operation and to running at a stable operating condition. The control of these plants makes use of different advanced process control strategies which include but are not limited to cascaded control, where multiple layers of control systems are applied, and model predictive control. These different control strategies can range from regulatory control to supervisory control. Because of the large number of inputs to these plants, efficient controllers are necessary to obtain desired results. The use of Nonlinear Model Predictive Control (NMPC) is an attractive option for most mineral processing plants because of the constraint management capabilities of the controller. Unfortunately, the NMPC method has a large computational load which requires sufficient resources to make it a viable option. Another model predictive control method known as Model Predictive Static Programming (MPSP) has shown promise to improve the computational time of a standard NMPC controller. The MPSP control philosophy generates a static optimization problem which is less computationally difficult to solve compared to the dynamic optimization problem that is generated through NMPC. In this dissertation, the control of a single-stage grinding mill circuit and a four-cell flotation circuit with an MPSP controller to reduce the computational load is proposed. The computational efficiency and the output performance of MPSP controllers are compared to NMPC controllers as a motivation for the use thereof. The comparison is done by simulating two mineral processing stages, namely the communition phase and the separation phase. The simulations considered different configurations for both the MPSP and NMPC controllers. The comparison of the controllers in the simulations shows that the MPSP controller obtained similar or improved plant results while also having a reduced computational time compared to the NMPC controller. The MPSP controller also displays scalability improvements compared to the NMPC controllers which can be beneficial for supervisory control of large-scale processing plants.
Advancing environmental, social, and governance outcomes through process optimisation and control
(University of Pretoria, 2024-02) Le Roux, Johan Derik; Craig, Ian K.; burchell.john@gmail.com; Burchell, John James
Organisations are compelled to integrate Environmental, Social, and Governance (ESG) considerations into their core strategy, with the tightening of regulatory requirements and the mounting pressure from stakeholders for sustainable practices driving a trend toward socially responsible investing. Advanced process optimisation and control provides innovative solutions to support ESG objectives. This thesis explores two case studies aimed at enhancing the consistency of material flow and composition into metallurgical operations to improve overall processing efficiency. The first case study introduces a (μ+λ)-Evolutionary Strategy (ES) to solve the input blending problem for a base metal refinery (BMR), where variability in the feed of contaminants to the operation impact negatively on plant throughput, product quality, and harmful emissions. The algorithm outperforms baseline blending strategies demonstrating a significant improvement in the blended consistency of contaminant feed. In the second case study, a nonlinear Model Predictive Controller (NMPC) is developed and implemented on a surge tank for level averaging control in an industrial tailings reprocessing circuit. A rigorous dynamic model is derived to describe the rate of change of both the volume and density in these surge tanks. By simulation with industrial data it is demonstrated that the significant input disturbances typical to tailings reprocessing circuits drive a gain inversion in the density model of the surge tank. This gain inversion and the multivariable objectives of both density and flow disturbance attenuation motivates for a NMPC solution. Results presented show significant improvements in both the water recovery and the stability of mass flow of tailings in the circuit. These advanced optimisation and control solutions support ESG objectives across multiple dimensions. Improved input stability with the (μ +λ)-ES enhances the efficiency of downstream processes where contaminants are extracted, resulting in lower emissions, especially when hazardous reagents are involved in the extraction process. By improving the efficiency of contaminant extraction the need for rework of product that fail to meet specifications is minimised, which leads to a reduction in waste generation, conservation of resources, and lower energy consumption. Improved water recovery with the NMPC lowers the overall environmental footprint of the tailings reprocessing circuit by reducing water consumption and energy usage, while stability improvements positively impact recoveries, thereby reducing waste and supporting responsible resource management.
Extremum seeking control of grinding mill circuits based on grind curves
(University of Pretoria, 2023-05) Le Roux, Johan Derik; Craig, Ian K.; lukieski@gmail.com; Ziolkowski, Lukasz
Mineral processing plants include several operations to liberate the valuable minerals within raw ore material to produce a concentrate, which is processed into a usable product by a metallurgical refinery. A mineral processing plant consists of a comminution and a separation stage. During the comminution stage, the raw ore material is processed through a grinding mill circuit to liberate the valuable minerals by grinding the ore to fine particles. The product from the comminution stage is then processed at a separation stage, which separates the valuable minerals (concentrate) from the waste material (tailings). The comminution stage plays a crucial role in the mineral processing industry. It significantly impacts the net revenue generated by a mineral processing plant due to the high operating costs associated with liberating the valuable minerals from the ore material. A grinding stage operates efficiently if it is processing the ore material at its maximum capacity, minimizing power consumption while reducing the amount of valuables lost to the tailings stream. Therefore, the ore material should be sufficiently ground for effective separation in subsequent downstream processes. Ideally, the separation stage requires a consistent stream of fine particles for effective separation. It is challenging for plant operators to manually achieve the above-mentioned operational objectives, which motivates the need to adopt a suitable control framework and ensure an efficiently run process. The performance of a grinding mill circuit is measured by its throughput and grind quality. These performance indicators are inversely related to operational objectives. The challenge in controlling the grinding mill circuit arises in determining the optimal operating conditions to maximize the net revenue generated by the plant. The optimal operating conditions vary with different ore types and unknown disturbances, such as varying ore hardness, which can result in the comminution stage operating at sub-optimal operating conditions. Furthermore, grinding mills rely on the cascading motion of the ore material and grinding media to accelerate ore breakage. The cascading motion is a function of the fraction of the mill volume filled with ore and the mill rotating speed, which influences the breakage forces that occur between rocks. Therefore, selecting optimal operating conditions is a difficult task requiring frequent adjustments as the operating conditions vary. Grind curves are a valuable tool that establishes the relationship between the mill load filling and rotational speed to the grinding mill throughput, grind quality and power consumption for a given ore type. Generally, the curves show parabolic features and the peaks vary with changes in the ore characteristics. A model-free adaptive control strategy is proposed for optimizing the performance of a semi-autogenous grinding (SAG) mill based on grind curves to improve throughput or grind quality. The controller explores an unknown map in search of the extremum of the performance indicators along the grind curves. A perturbation-based (PESC), a time-varying parameter estimation-based (TESC), and a Nelder-Mead simplex-based (SESC) extremum seeking control method are considered to optimize the grinding mill performance. Several optimization strategies are investigated for an open grinding mill configuration and a closed grinding mill circuit, where the closed circuit is equipped with a screen or with a hydrocyclone classifier to recirculate oversized ore material for additional grinding. The challenge lies in implementing an efficient optimization model-free control framework that will effectively maximize the performance measures of the complex, non-linear behaviour of the grinding mill circuit.
Model-based estimation and control of wheel slip in locomotives
(University of Pretoria, 2023-10) Le Roux, Johan Derik ; charlvandemerwe@gmail.com; Van de Merwe, Charl Viljoen
This dissertation investigates wheel slip control of locomotive traction systems in the presence of non-linear wheel surface behaviour and varying adhesion conditions. It is difficult to determine when the maximum point of adhesion has been exceeded since the adhesion coefficient cannot be measured directly during the operation of the locomotive. Therefore, classical slip controllers suppress excessive slip by using predetermined thresholds for the slip velocities and accelerations of the axles. The classical methods are convenient but cannot maximise adhesion utilisation. Modern methods continuously modulate the torque and are expected to produce superior performance if implemented effectively. Most continuous controllers calculate the reaction torque using a generated slip ratio (slip velocity divided by the locomotive velocity) reference and a slip ratio estimate feedback. Computing the estimate depends on an accurate locomotive velocity estimate, which is difficult to obtain when all the wheelsets of a locomotive are driven. Slip ratio reference generation generally requires estimates of the slip ratio and adhesion coefficient or adhesion force. This dissertation focuses on producing accurate estimates to enable effective slip control. Adhesion force is the adhesion coefficient multiplied by the normal force. The adhesion coefficient is dependent on the rail conditions. Under constant rail conditions, it varies only with a wheel load and slip ratio change. Therefore, the normal forces, wheel velocities, and locomotive velocity should be modelled accurately to ensure the model produces realistic adhesion coefficients. A linearised railway vehicle model could be well over the 100th order. Such models are helpful for design and validation, but using such complex models in model-based filter or estimator design is impractical. In this dissertation, a new simulation model is developed that includes the longitudinal, pitch, vertical, and wheelset rotational dynamics. In addition, it includes a unique approach to the coupler force by modelling the wagons using a single-axle wheelset model. This model captured the desired dynamics, including wheelset torsional vibrations and oscillations in the pitch dynamics. A linear state-observable estimator is developed to produce estimates of slip ratios and adhesion coefficients. The estimation model is an adaptation of the simulation model, but the adhesion forces and coupler force are modelled as unknown disturbances. This estimator requires measurements of the locomotive longitudinal acceleration and velocity, body pitch angle and rate, and the motor angular velocities. The rail angle and motor torque estimates should be provided to the estimator. The estimates are used in a novel slip ratio reference adaptation method to provide a reference to an adaptive PI controller. The PI controller is used to compute the reaction torque to prevent unstable slip in the rear/reference wheelset, while a speed differential controller is used to prevent slip in the other wheelsets. The simulation results indicate that the estimator and controller configuration can suppress unstable slip under varying adhesion conditions, thereby preventing damage to the wheels and rail while ensuring maximum adhesion utilisation. Maximum adhesion utilisation allows a locomotive to increase its hauling capacity without increasing its mass.
A one health assessment of a “Herding for Health” project at the wildlife-livestock interface in western Ngamiland, Botswana
(University of Pretoria, 2021-10) Quan, Melvyn; Van Rooyen, Jacques; McNutt, John W.; bheermans@yahoo.com; Heermans, Ben Cooper
This PhD thesis titled, ‘A One Health assessment of a Herding for Health project at the wildlife-livestock interface in western Ngamiland, Botswana’, analyzed data collected from an applied Herding for Health (H4H) project implemented in western Ngamiland, Botswana. The H4H model was first established at the Department of Veterinary Tropical Diseases at the University of Pretoria to apply One Health principles that acknowledge the interconnectedness of human, animal and ecosystem health. The model aims to assist agropastoral communities in the transfrontier conservation areas (TFCAs) of southern Africa with the dual objectives of poverty eradication and biodiversity conservation. A mixed-methods approach was used to investigate some of the key assumptions of the H4H model. The thesis is comprised of five chapters: Chapter 1, an introduction to the H4H model and a literary review of the methodology of subsequent chapters; Chapter 2, ‘One Health profile and farmer’s perceived risk analysis for an agropastoral community in the Khaudum-Ngamiland Wildlife Dispersal Area of the Kavango–Zambezi TFCA’, that used a qualitative and quantitative survey approach to investigate community sentiments on animal and rangeland health, regional constraints to livestock husbandry and human-wildlife conflict; Chapter 3, ‘An environmental template and drivers of functional heterogeneity in communal rangelands of the western Okavango Delta’, which used community survey and rangeland sampling techniques to explore how H4H can address the piospheric nature of rangeland degradation; Chapter 4, ‘Husbandry and Herding: a community-based approach to address illegal wildlife trade’, which used a Theory of Change approach developed with input from relevant stakeholders to guide how H4H could address the current trend of diminishing wildlife populations around the Okavango Delta and Chapter 5, ‘Conclusions’, which summarizes the major findings of the dissertation and provides recommendations for H4H project interventions and for further research. Some of the key results from this thesis illustrate the importance of cattle rearing in western Ngamiland, Botswana which was the main source of household income for 97% of respondents. While most residents were satisfied with the advice supplied by local veterinary extension services, animal diseases continue to be a major challenge to farming, surpassed only by the related factor of constraints to market access due to Foot and Mouth Disease control policies. While diseases account for 7.7% of total cattle losses, the greater loss reported is due to straying animals which account for 60.3% of total losses whereas predation accounts for 22.9%. The herding and kraaling activities promoted by H4H are ideal interventions to address losses to disease, livestock-wildlife conflict as well as stray animals. Stray cattle are a likely threat to animal disease control and may explain regional FMD outbreaks outside of buffalo (Syncerus caffer) ranges, which is a topic outlined for further research. The potential for planned grazing and kraaling to address rangeland health is exemplified in the environmental template which demonstrates higher wildlife utilization in abandoned kraal sites and the effect that high-density grazing has on rangeland species composition including functional attributes such as stem height, tuft basal width, the distance between tufts and grass abundance which are significantly influenced along the grazing gradient. Lastly, the H4H Theory of Change identifies three pathways based on community-level actions to address illegal wildlife trade in the region which include: increasing institutions for local enforcement, developing incentives for ecosystem stewardship and decreasing the costs of living alongside wildlife. The success of the pathways depends on underlying enabling actions related to supporting the development of institutional frameworks, building community capacity and strengthening a Conservation Agreement model to facilitate informed best farming practices targeted to increase community and ecosystem resilience to economic shocks.
Nana's living library : an outdoor South African floral library in Pretoria CBD
(University of Pretoria, 2024-11) Shand, Dayle; mariette.dekock01@gmail.com; De Kock, Maureen
Urbanisation increasingly diminishes the availability of open space in cities, creating a disconnect between people and nature, especially in the heart of the Pretoria Central Business District (CBD), along Nana Sita Street. Here, local communities are restricted to poorly maintained public parks and occasional visits to natural landscapes, outside of the city, for brief interactions with nature. Meanwhile a deep connection with natural elements like flora is an important part of people’s lives. A notable example of lack of engagement is that local floral knowledge is primarily restricted to botanical gardens and nature reserves on the city’s outskirts. This project addresses these challenges by proposing a spatial framework to reintegrate nature within Tshwane’s inner city, emphasising underrepresented floral knowledge exchange. Central to this initiative is exploring methods of knowledge sharing and translating it to landscape architectural elements. Nana Sita Street serves as the primary spine of the precinct development, with improved pedestrian conditions and pathways, creating a network of new and existing green spaces in the CBD as satellite floral gardens. These foster improved human-nature relationships, celebrating authentic interactions with locally indigenous plants by transforming current derelict open spaces into gardens with medicinal, edible, culturally significant and useful plant species. The proposal is further detailed on one site within Nana Sita Street, where leftover space is transformed into an outdoor floral library complete with a discussion pavilion, exhibition walls, herbarium, workshops and demonstration areas. Other proposed development includes the repurposing of a petrol station into a vegetated area, adding residences, play areas and shops. The owner of the site, FABA Properties Ltd is considered to be the primary client and collaborates with the South African National Biodiversity Institute and the Future of the City Centres Network, which focuses on improving city centres. The proposal serves the diverse community, including working professionals, school children, theatre goers, families and visitors from surrounding areas. Overall, this proposal acts as a catalyst to highlight the importance of good quality urban green spaces, advocating for alternative representations of urban nature that integrate floral knowledge and its significance within local human-nature relationships.
'n Kwalitatiewe ondersoek na die emosionele belewenis van enkele Suid-Afrikaanse blanke geskeide mans
(University of Pretoria, 1992-02) Du Preez, M.S.E.; sulette.ferreira@gmail.com; Ferreira, Sulette
Afrikaans: Hierdie ondersoek lewer 'n beskeie bydrae tot die verkryging van wetenskaplike kennis oor mans se ervaring en hantering van egskeiding waaroor weinig, veral in Suid-Afrika, bekend is, asook tot die verskaffing van maatskaplikewerk-hulp aan mans wat in Suid-Afrika hierdie lewenskrisis beleef. Ten einde die ondersoek te kon doen, is die doelstellings van die ondersoek soos volggestel: Om deur middel van 'n verkenning van die bestaande literatuur oor egskeiding die sentrale teoretiese modelle te bepaal en te beskryf wat deur sosiaal-wetenskaplikes gekonstrueer is om egskeiding te begryp, en terapie te verskaf aan diegene wat daardeur geraak word. Om deur middel van 'n plooibare navorsingsbenadering, te wete die kwali tatiewe model, eerstehandse inligting te bekom rakende enkele geskeide blanke Suid-Afrikaanse mans se sosiale werklikheid, dit wil se hoe hulle sin en betekenis aan hul egskeidings gee. Om te let op die behoefte van die geskeide man aan terapeutiese hulpverlening en op grond hiervan aanbevelings te maak aan die Suid-Afrikaanse maatskaplikewerk-praktyk. Om 'n bydrae tot die metodologie van maatskaplikewerknavorsing in Suid-Afrika te lewer deur prakties te illustreer hoe die kwalitatiewe navorsingstyl wat tot nog toe selde in plaaslike maatskaplikewerk-studies onderneem is, aangewend kan word om geskeide mans se definisies van hul situasies, of meer spesifiek, hul subjektiewe ervarings en interpretasies van hul lotgevalle, te peil en te beskryf. Hoewel vandag algemeen aanvaar word dat een uit elke drie huwelike in Suid-Afrika in die egskeidingshof eindig, is wetenskaplike literatuur oor die probleem in die land beperk. Verder blyk dit dat weinig teoretiese en empiriese inligting spesifiek oor die geskeide man hier te lande beskikbaar is. Hoewel aansienlik meer aandag in die buiteland aan egskeiding gegee word, blyk dit dat sosiaal-wetenskaplikes veral in die geskeide vrou geYnteresseerd is en dat haar eweknie, te wete die geskeide man, verwaarloos word. Nogtans is waardevolle inligting uit die beskikbare literatuur onttrek oor die egskeidingsproses en oor sowel die geskeide vrou as die geskeide man. Die insigte wat van die onderskeie teoretici en navorsers verkry is, was nie alleen nuttig om die data te interpreteer wat tydens die empiriese studie ingesamel is nie, maar hou belofte in vir sowel verdere plaaslike studies van geskeide mans as vir hulpverlening aan hulle. Vyftien geskeide blanke mans is met behulp van die sneeubaltegniek opgespoor en tot deelname aan die empiriese studie oorgehaal. Hierbenewens is twee geskeide mans op dieselfde wyse gewerf om die navorsingsresultate te verifieer. Bestaande riglyne vir kwalitatiewe navorsing is sover moontlik in die studie toegepas en daar is daarin geslaag om, hoewel nie uitvoerig nie, 'n getroue prentjie van die lewensituasie van die geskeide blanke man te beskryf. Die data is verkry deur onderhoude (semi-gestruktureerd maar ook ongestruktureerd) met die respondente te voer en deur dokumente te benut wat hulle vir hul eie gebruik of op versoek van navorser opgestel het. Afgesien van die dokumente is van oudiobande gebruik gemaak en die byhou van notas om die verkree data vas te le. Die data is voortdurend bestudeer en is veral aan die einde van die ondersoek in temas en patrone gekategoriseer en geYnterpreteer met behulp van sekere bestaande teoriee wat tydens die literatuurverkenning afgebaken is. Regdeur die ondersoek is sover moontlik gepoog om faktore te neutraliseer wat die resultate nadelig kon beYnvloed. Die slotsom waartoe uiteindelik geraak is, is dat die lewensituasie van die aantal geskeide mans wat as proefpersone benut is, geldig en akkuraat verken en beskryf is. Die belangrikste bevindinge van die empiriese studie is die volgende: Egskeiding is 'n proses met fases wat onderskei maar nie geskei kan word nie; die geskeide man ervaar verskeie emosionele belewenisse voor, tydens en na afloop van die egskeiding; die aanpassing aan die egskeiding word deur verskillende faktore geaffekteer; egskeiding het 'n effek op die verhoudingslewe van die geskeide man; die godsdiensbeskouing van die geskeide man speel 'n kardinale rol in sy verwerking van die egskeiding en ten slotte het die geskeide man behoefte aan terapeutiese intervensie. Dit blyk dat geskeide mans by maatskaplikewerk-hulpverlening kan baat mits sodanige programme in samewerking met hulle opgestel word.
Mathematics teachers' professional noticing as an immanent feature of Lesson Study
(University of Pretoria, 2024-09) Sekao, David; u18229256@tuks.co.za; Moremi, Koketso Clinton
Teachers’ professional noticing is an essential pedagogical skill for the effective teaching and learning of mathematics. Professional noticing is an inherent attribute of Lesson Study (LS). Therefore, LS is the perfect context to explore how mathematics teachers used professional noticing when offering lessons within the LS setting; thereby making instant instructional decisions while the lesson unfolds. My qualitative case study research is situated within the interpretivist paradigm, wherein two LS groups were studied to gain insights into how mathematics teachers’ professional noticing informs their instructional decisions. I used two theoretical lenses, namely, Situated Learning Theory (Lave & Wenger, 1991), to provide a theoretical basis for LS and FOCUS Framework for Productive Noticing (FFPN) (Choy, 2015) to provide a theoretical basis for professional noticing. The two LS groups were purposively selected because of their familiarity with and implementation of LS. Data were collected through observation, document analysis and unstructured interviews to answer the primary research question: How do mathematics teachers use professional noticing to facilitate lessons within LS? The findings of this research have practical implications for mathematics teaching. The study revealed that while teachers noticed learners struggling with specific mathematics ideas, their noticing was only superficial. This led to instructional decisions that were not optimal for enhancing or developing learners’ mathematical thinking. The dominant instructional decision was to, in the same way, re-explain a mathematics idea in the same way when learners were struggling with it. The study also revealed that teachers could reflect on practice cosmetically and suggest alternatives for the future. The recommendations from this research can guide teachers to use purposeful activities when teaching in the LS context to enable them to notice specific issues regarding learners’ mathematical thinking and then make suitable instructional decisions. It also suggests that teachers consult curriculum policy when engaging in post-lesson reflections to enrich their reflection-on-practice.
Visualising M’bona religious beliefs and practices : a visual cultural artistic co-production with the custodians of Khulubvi and Associated Rain Shrines in Nsanje, Malawi
(University of Pretoria, 2025-06) Kriel, Lize; Beyers, Jaco; mamayewo@gmail.com; Chikabadwa, Eva
The study examines the role of the visual in research and documentation by analysing the power relations between the visual, oral, and written forms in the context of heritage preservation, drawing on theories of visual culture. The project aimed to visualise the M’bona beliefs and practices for the adornment of a future museum in a manner that strikes a balance among the three (visual, oral, and written) for heritage sustainability. The vision aligns with the concept of ‘decolonizing heritage for development,’ where development encompasses improvements in both material and non-material aspects, the ability to help others, and a change in individual and collective circumstances. Heritage, on the other hand, comprises skills, knowledge, and practices. In short, heritage development is a consequence of heritage and heritage making. The study organized the data using Ninian Smart’s seven dimensions of religion. It employed Clifford Geertz’s definition of religion, Talal Asad’s critique, the African Traditional Religions framework, and participants’ views to examine the M’bona culture as a religion. The Manganja M’bona advocates asserted that they do not consider the term ‘religion’ applicable in their culture. An experimental research approach, the ‘Meta Picture Data Collection Technique,’ which strikes a balance between textual, oral, and visual elements of heritage while prioritizing community involvement, was developed and used in the study. The technique aims to balance practice and theory in visual culture by emphasizing artmaking as a holistic approach, much like reading and writing texts for deeper studies.
Delinquency of the youth in rural Bisho : a pastoral challenge
(University of Pretoria, 2024) Masango, Maake J.S.; lindelwakumbaca@gmail.com; Kumbaca, Lindelwa
This exploratory study investigates the root causes of youth delinquency in rural Bisho, focusing on the complex interplay of social, educational, and environmental factors influencing adolescent behaviour. Youths in rural communities face challenges stemming from their interactions within schools, religious institutions, and the broader community, as well as from peer and adult relationships. Many young individuals join gangs to establish a shared identity or pursue specific objectives, often rooted in criminal or delinquent activities such as drug trafficking, substance abuse, and other unlawful behaviours. Understanding the underlying causes of youth delinquency is essential for designing effective interventions and operational resolutions to social problems. This research highlights key factors contributing to criminality among rural youth, with a particular focus on the socio-environmental context of Bisho, Kwatyutyu. Addressing this pastoral challenge requires collaboration among clergy, faith communities, and stakeholders, emphasizing their responsibility to nurture children as gifts from God. Delinquent behaviours, including truancy, drug use, violence, property crimes, and interactions with the criminal justice system, were analysed using regression models to assess their impact on educational and occupational outcomes. Findings reveal that youth delinquency significantly hinders educational attainment for both males and females, even after controlling for standard status attainment variables. Furthermore, while delinquency consistently affects male occupational outcomes, its impact on female occupational outcomes is comparatively weaker. The study underscores the importance of examining successful intervention programs from similar contexts to inform strategies aimed at mitigating youth delinquency in rural settings. Insights gained from the study, contribute to a deeper understanding of the factors shaping delinquent behaviour and inform policies aimed at fostering positive youth development.
Clinician and patient views on antiretroviral treatment integration in primary health care clinics, Tshwane, South Africa
(University of Pretoria, 2014) Hendricks, S.J.H. (Stephen); Bergh, Anne-Marie; stephen.hendriks@up.ac.za; Mathibe, Maphuthego Deliah
Background: Primary health care (PHC) clinicians and patients are major role players in the South African antiretroviral treatment programme. Understanding their perceptions of integrated care and the management of people living with HIV/AIDS in PHC facilities is necessary for successful implementation and sustainability. Objective: This study explored clinician and patient perceptions of integration of antiretroviral treatment in PHC clinics. Method: An exploratory, qualitative design was used. Four City of Tshwane PHC facilities were purposively selected, two urban and two rural. A self-administered questionnaire was distributed to 35 clinicians and four focus group interviews were conducted with HIV patients. Results: Models of care implemented were: full integration; partial integration; and separate services. Workload, staff development and support for integration affected clinicians’ performance and viewpoints. Promotion of privacy, reduced discrimination and increased access to comprehensive care were perceived as benefits of service integration and delays, poor patient care and patient dissatisfaction as negative aspects. In three facilities patients were satisfied with integration or semi-integration and felt common queues prevented stigma and discrimination, while the reverse was true in separate services. Single-month issuance of antiretroviral drugs and clinic schedule organisation were viewed negatively, as well as staff attitudes, poor communication and long waiting times. Conclusion: Integration of ART service in primary health services improved accessibility of the comprehensive service packages and coverage. The fully integrated model shared resources and had equitable work distribution amongst clinicians.
Peace mediation : the role of John 7:53–8:11 for possible conflict management in reformed churches in northwest region of Cameroon
(University of Pretoria, 2025-04) Hombana, Mphumezi; rogertem1@gmail.com; Tem, Roger M.
No abstract
Sabbatian influences on the Chassidic and Mitnagdic movements : an excursion into messianic Kabbalah and its disseminators in the aftermath of Shabbatai Tzvi
(University of Pretoria, 2024-08-30) Human, Dirk J.; baalshem@global.co.za; Michal, Gavin
This study hypothesises that as a result of a thorough analysis of the context and content of rabbinic texts, including the known associations of their authors − spanning the periods of Shabbatai Tzvi, the Baal Shem Tov and the Vilna Gaon − the conclusion can be reasonably drawn that the Chassidic and Mitnagdic movements had been fundamentally subjected to multiple Sabbatian influences and that a causal doctrinal and rabbinic link between Sabbatianism and both the Chassidic and Mitnagdic movements can be demonstrated.
Redefining the church's mission : towards a contextual and missional ecclesiology in responding to poverty in South Africa
(University of Pretoria, 2024-09) Dreyer, Willem Akkerhuys (Wim); bernardprinsloo@yahoo.com; Prinsloo, Christoffel Bernardus
This research critically examines the transformative potential of adopting a contextual and missional ecclesiology to enhance the Nederduitsch Hervormde Kerk van Afrika's (NHKA) engagement with poverty alleviation in South Africa. Against the country’s severe socio-economic challenges, the study seeks to redefine the church's mission in addressing this pervasive issue more effectively. Central to this investigation is the hypothesis that a shift towards missional ecclesiology – rooted in the Trinitarian mission of God - can significantly empower the NHKA to respond more effectively to poverty. This approach calls for moving beyond traditional ecclesiology models to embrace responsive, contextually informed practices that align with the missio Dei. The research integrates historical reflections on the NHKA's involvement in poverty alleviation, theoretical explorations of missional ecclesiology, and practical considerations for the church's societal engagement. It aims to bridge the gap between ecclesiological theory and the practical realities of addressing socio-economic challenges in contemporary South Africa. Key concepts such as missional ecclesiology, diaconal ministry, and contextual theology are foundational to understanding the proposed shift in the NHKA’s approach to its mission. The study posits that by re-envisioning its mission and practices in light of these concepts, the NHKA—and other ecclesial bodies—can significantly enhance their impact on poverty alleviation. Ultimately, this research contributes to the broader ecclesiology and social engagement discourse in South Africa. It highlights the church's potential as a transformative force in society, emphasising the importance of theological reflection, historical awareness, and actionable strategies in driving its mission forward. This thesis advocates for a missional reorientation of the church’s role in society, suggesting that deeper engagement with the gospel's transformative power can lead to more effective responses to the urgent challenge of poverty in South Africa.
Religious (in)tolerance in digital narratives : a critical analysis of how religious studies professionals can play a role in the responsible use of digital narratives
(University of Pretoria, 2024-08) Beyers, Jaco; marykestryds@gmail.com; Strydom, Maryke
This thesis was focused on the complex relationship between religion, tolerance, religious education, and narrative. The digital world is lending a steady stream of narratives toward humanity on a daily basis. Narratives are not just a mere form of entertainment but form part of the information received by humans. The thesis explored how narratives can potentially impact the human mind through narrative theories. Narrative theories showcase why narratives may help increase the effectiveness of fact-based learning. The constant availability of narratives leads to questions about the accuracy of the information found within the narratives. Narratives contain information on a myriad of topics and disciplines. This thesis focused on religious people and phenomena as portrayed in narratives. Although not all narratives are concerned with religion, a large amount of information on religion can be found within narratives. This thesis was based on a quantitative literature review. The main concern was how the responsible use of narratives can be encouraged through religious education settings (non-confessional). The thesis is not a curriculum for a specific context but rather considers the use of digital narratives within religious education settings in a global technology and narrative-forward context. The thesis showcased why digital narratives and the information found therein are important. As many different geographical spaces are becoming more multireligious, propagating tolerant multireligious societies is important. Narratives can have accurate and valuable information that people can learn from throughout their lives. This can partly be achieved through para- social interaction with narrative characters, building curiosity about phenomena found in narratives and practising a conscious retrospective reflection. However, many narratives have inaccurate, stereotypical, or dehumanising views on religious constructs and the people who adhere to them. These types of depictions can lead to an increase in intolerance if digital narrative users do not view the information critically. Therefore, there is a duality of (in)tolerance within the information found within digital narratives. As narratives may create or inhibit tolerance, it is of great importance for religious studies specialists to take note of the dualistic nature of narratives. Therefore, the large number of digital narratives within the public sphere has implications for religious education.
Rethinking iconicity : exploring the iconologies of apartheid-era documentary photography and South African networked social movements
(University of Pretoria, 2024-06) Du Preez, Amanda; deneesherpather@gmail.com; Pather, Deneesher
This thesis addresses the question of how political narratives are configured as aesthetic issues in selected images from apartheid, #AmINext and #FeesMustFall. The research questions are explored through iconological and hermeneutical interpretation. Sixty documents were collected for interpretation, thirty documentary photographs from the apartheid-era, fifteen images from #AmINext, and fifteen images from #FeesMustFall. The images were coded using the qualitative analysis software ATLAS.ti, and thematically curated using the online whiteboard platform Miro. Additional examples of what I refer to as “politically charged images” (PCI) were added to the Miro whiteboard to illustrate an aesthetics of politically charged imagery. The study addresses three main objectives. Firstly, through a Rancièrian theoretical framework, I explore how an anti-apartheid narrative is configured in apartheid-era documentary photographs, primarily through interpreting selected photographs by David Goldblatt and Ernest Cole. Second, I examine how political images can communicate similar political, social and cultural issues despite distances in time and space. Third, I interrogate the movement of past political images to online platforms and their interactions with more recent politically charged images on online platforms. I put forward the idea that politically charged imagery are constructing imagic conversations on shared social issues through time and space. I offer a renewed perspective on iconicity as a category for interpreting the political messages read in images. In my determination of the word, iconicity refers to the underlying qualities of images that inspires a sense of likeness, resonance, recognition and memory-recall. Whereas previous uses of iconicity have focussed on the word as a category to interrogate the material basis of icons as culturally impactive, my determination of the word stresses the immaterial aspects of image communication. Using Jacques Rancière’s concept of the aesthetic image, I position the selected apartheid-era photographs as constructing the politics of apartheid. The affective images of apartheid-era documentary photography contribute to an archive of virtual imagery that speak both to the local issue of apartheid and related universal issues connected to racial injustice, police brutality, and social inequalities. The images of #AmINext and #FeesMustFall are also argued to be affective images that have the potential to speak to other related social movements. In both networked social movements, the activists engage in body politics that make otherwise hidden violences visible. Lastly, I argue that the iconologies of #AmINext and #FeesMustFall consist of several perspectives of the movement formed through machinic interventions, images from the past and images that point to an empowered future for the activists.
Worship and church building in small congregations : challenge and potential – an empirical-theological analysis of the practice of worship in correlation with church building in small free church congregations in Switzerland
(University of Pretoria, 2024-08) Ott, Bernhard; Lombaard, Christo; rafael.vonarx@bluewin.ch; Von Arx, Rafael
This thesis examined the worship service of small free church congregations in Switzerland and its effects on church development. Social science research was carried out using grounded theory methods to answer the question of which liturgical forms and content, from the perspective of worship participants, make it difficult or support church development. This revealed that worship in small churches represents a staged activation that leads to the congregation being built up. In concrete terms, this means that worship participants are so encouraged by the worship experience that they want to let others participate in the worship service and the spiritual experiences associated with it. They therefore begin to put a lot of effort into designing the worship service so that first-time visitors can feel comfortable in addition to regular visitors. This means that worship participants are involved in working in the worship service, but also in other areas of the church. This in turn leads to joint development of strategies to further develop the worship service and the church. These strategies then shape the characteristics of the congregation, which contribute to regular worshipers identifying more with the congregation, but also to outsiders becoming aware of the congregation and attending the service. These observations make it clear that the worship service of small congregations plays a central role in building up the congregation. The most important liturgical elements emerged as the sermon, praise and fellowship. Since these three core elements in particular were assessed very differently due to different individual needs, a final clarification of the initial question was only possible to a limited extent. Only the SWOT analysis carried out afterwards, with its strong practical relevance, enabled a differentiated evaluation. There it became clear that it was less about the individual elements and more about the interplay between worshipers, liturgical forms and the associated interactions. In detail, it was shown that the liturgical forms in the worship service of small free church congregations contribute to the building of the congregation when the worship participants attend the service with spiritual expectations and can help shape it through (spontaneous) participation. Other important factors are the integration of the different generations in the worship service and the worship service information on other congregational activities.
Widening readership – a case study of the translation of indigenous law
(University of Pretoria, 2015-03) Titlestad, Peter J.H.; idette.noome@up.ac.za; Noomé, Idette
This thesis explores the translation into English of an Afrikaans academic text in the field of legal anthropology focusing on the indigenous law practised among the Nkuna of Ritavi: Boonzaaier’s (1990) Die familie-, erf-, en opvolgingsreg van die Nkuna van Ritavi met verwysing na ander aspekte van die privaatreg. It aims to discover how to produce accountable translations of such texts for different audiences to widen access to information on indigenous law. Such texts are now used in court cases under common law and in the higher indigenous courts, but are not all available in a lingua franca. This qualitative study presents an autoethnographic research narrative, and uses the critical friend methodology to underpin the practical translation of the case study text. Central historical translation theories of equivalence are reviewed. They persist in the Anglo-American translation tradition, which requires ‘transparent’ translation, rather than word-for-word faithfulness. Choices regarding functional equivalence depend on the Skopos (purpose) of texts. Hermeneutic theories, including Iser’s reader aesthetic theories and Gadamer’s concept of horizons of expectations, illuminate the position of translators as readers. The autoethnographic research narrative reveals a sympathetic widening of the translator’s horizons in engaging with the text in the context of her cultural, educational, socio-political and socio-economic positioning. The study shows that feminist theory provides useful metatextual strategies to increase the visibility, and hence accountability, of translators. Post-colonial theories highlight the importance of power relations surrounding translations in the South African context. The study argues that most translation theory focuses on literary translation, not ‘use’ texts such as the case study text, but the concept of ethnographic research narratives and various aspects of ethnographic texts allow literary translation theories to be applied to Boonzaaier’s text. A ‘negotiation’ model of translation is shown to be useful, especially linked to the critical friend methodology (the author of the case study text was interviewed about indeterminacies in the text and about its Skopos). The translation is complicated by the fact that the text focuses on elements of Nkuna culture, which differs from the cultures associated with the start language (Afrikaans) and the target language (English). The annotated academic translation for academics and members of the judiciary reveals problems in translating gender terms which require explicit intervention in the translation. Generic problems in such texts include differential treatment of men and women under indigenous law, non-equivalent legal terminology in the Nkuna and common law systems, and opposing legal and social paradigms – differences which need to be made explicit rather than elided to achieve a ‘thick translation’. Because of the time that has passed since the start text was written (1990), the text also requires updating regarding applicable national legislation and geopolitical designations. Other areas addressed are specific Nkuna terms, currency changes, and the use of tenses in the text. The thesis also explores interactions with aspects which may be offensive or disturbing to readers. The thesis proposes Plain English possibilities for a diverse Nkuna readership, in the context of the language debates in South Africa. Plain English is, by default, essential in South African conditions to widen access to scientific material. South Africa differs from countries where Plain English norms initially developed, so these norms require adjustment. The thesis shows the applicability of interlingual translation theories for intralingual (Plain Language) translation, and recommends further testing of the strategies in the field. It also recommends the use of autoethnography and the critical friend methodology in Translation Studies.
The impact of innovation climate and diversity on inclusive leadership and innovative work behaviour in South African organisations
(University of Pretoria, 2024-11-04) Scheepers, Caren; ichelp@gibs.co.za; Lombard, Wilhelmus Hermanus Adriaan
Businesses need to innovate to remain competitive in their respective markets. Diversity and the appointment of a diverse workforce are promoted as enablers of innovation within organisations. However, appointing diversely without creating inclusivity and promoting an innovative climate, proves to have negative effects on innovation within the organisation. Therefore, to fully harness the advantages of a diverse workforce, several other aspects need to be considered to promote innovation that will assist organisations in remaining competitive in their markets. The purpose of the study was to examine the effect of innovation climate on the relationship between inclusive leadership and innovative work behaviour. Furthermore, differences in race and gender within the leader-follower relationship were tested to measure the impact of the relationship on innovative work behaviour which could stem or promote innovation. This study used a mono-method quantitative methodology with a survey questionnaire as measurement instrument. The unit of analysis was knowledge workers within South African organisations, reporting to a direct manager/supervisor within their organisation. The outcome proved the existence of a significant relationship between inclusive leadership and innovative work behaviour. Full mediation was measured when implementing innovation climate as mediator proving that innovation climate improves the relationship between inclusive leadership and innovative work behaviour. Finally, no evidence was obtained in so far as gender or race diversity impacting the relationship between inclusive leadership and innovative work behaviour. The study therefor adds to literature a method for testing innovative work behaviour through inclusive leadership in developing countries.
Role demands, constraints and choices: The impact of context and stakeholder expectations on business incubator managers’ strategic agency
(University of Pretoria, 2024-10) Marks, Jonathan; Olivier, Johan L.; ichelp@gibs.co.za; Gwarega, Dambudzo
This study examines how stakeholders’ expectations influence the behaviour of business incubator managers, as demonstrated by their strategic agency. While existing research acknowledges the potential of effective business incubator management in fostering successful new ventures, it does not delve into this role's complex and contextual nature, particularly in developing economies. Understanding how stakeholder expectations influence incubator managers’ strategic agency enhances understanding of managerial role behaviours in different operating contexts and helps improve business incubation practices. Role theory posits that a role occupant’s behaviour is shaped by the demands and constraints emanating from the members of the role-set’s expectations, with little focus on the occupant’s agency. However, organisation and management literature show managers have agency and can enact their roles. Therefore, foregrounding this literature, the study answers, “In what way do stakeholders’ role expectations enable and/or constrain the strategic agency of business incubator managers in a resourceconstrained context?” The study uses a qualitative, multiple case study design involving six business incubators purposively selected in South Africa, a resource-constrained emerging economy in sub-Saharan Africa. The data were thematically analysed using abductive reasoning anchored by the role theory framework. The findings underscore the continuous struggle of incubator managers to gain and maintain the incubator's legitimacy. Gaining legitimacy hinges on delivering visible performance impacts, adhering to the incubator's mandate, and bolstering its reputation. This balance between performance impact, incubator sustainability, and reputation is the central driver of the incubator manager’s strategic agency. The findings enrich role theory by illustrating that the demands managers face, driven by stakeholders' expectations, can act simultaneously as both constraints and enablers of strategic agency. For practice, the findings inform policy regarding entrepreneurship support through business incubation in a resourceconstrained context. Moreover, practitioners can benefit from insights into how misaligned stakeholder expectations constrain incubator managers’ strategic agency. Furthermore, insights into the impact of organisational structures on incubator managers’ performance can inform incubator institutional arrangements and management practices suited to the contextual demands.

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