Electronic Theses and Dissertations (Masters)
Permanent URI for this collectionhttps://hdl.handle.net/10539/37972
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Item Supply Chain Risk Management in Manufacturing Small and Medium Enterprises: A Systematic Literature Review(University of the Witwatersrand, Johannesburg, 2024) Pungula, Vusumuzi; Sunjka, B.Background: Small and Medium Enterprises (SMEs) are becoming major actors in the manufacturing sector due to the rising complexity of global supply chains. However, they still face enormous risks from supply chain disruptions and market dynamics, which can have costly effects. SMEs sometimes lack the means and expertise to execute comprehensive risk management plans intended for larger businesses, despite their significance. Research on Supply Chain Risk Management (SCRM) specifically for small and medium-sized enterprises (SMEs) is noticeably lacking, especially in the manufacturing sector. Purpose: The aim of the study was to systematically review how SCRM has been developing in manufacturing SMEs globally over the past two decades, and provide insights for policymakers, industry associations, and SMEs themselves. Method: A Systematic Literature Review (SLR) was conducted by utilizing a qualitative research approach. Seven key phrases were formulated to guide the search for relevant articles published between 2000 and 2023. A thorough screening process was employed to select 38 articles that met inclusion criteria, and data analysis was performed using NVivo software on these articles. Following this, thematic analysis and textual narrative synthesis methods were employed for data analysis and synthesis. The discussion of the identified themes provides comprehensive insights to policymakers, industry associations, and SMEs into the current status of SCRM research in manufacturing SMEs globally. It highlights the importance of effectively addressing risk variables, developing tailored SCRM approaches, and striking a balance between risk reduction efforts and strategic opportunities within supply chains to enhance resilience and ensure operational continuity. Results: The review revealed a significant increase in SCRM research pertaining to manufacturing SMEs over the past decade. Trends analysis indicated a growing emphasis on SCRM in various disciplines, highlighting its increasing significance. Thematic analysis identified eight key themes, including the current status of SCRM research and factors influencing SCRM strategies in manufacturing SMEs. Conclusion: Based on the comprehensive review of literature, several key conclusions can be drawn. There is prevalent recognition of the importance of SCRM within SMEs, emphasizing the need for proactive risk mitigation strategies tailored to the SME context. While formal risk management approaches are increasingly adopted, the context-specific nature of risk management practices highlights the importance of tailored approaches. Technological advancements play a significant role in enhancing SCRM strategies, alongside the integration of green supply chain management practices.Item The improvement of the on-time delivery for “company x” e-commerce orders during the golden quarter(University of the Witwatersrand, Johannesburg, 2024) Sukazi, Thobile Nomalungelo; Sunjka, BernadetteE-commerce has revolutionized global business and consumer interactions, offering convenience and accessibility across various domains like Business-to-Business (B2B), Business-to-Consumer (B2C), and Consumer-to-Consumer (C2C). The COVID-19 pandemic has accelerated digital transformation, with South Africa's e-commerce market showing robust growth projections, fuelled by factors such as improved internet penetration and shifting consumer behaviours. The Omni-channel strategy has become standard, with leading players leveraging digital capabilities to maintain market share. Notably, the "Golden Quarter" of retail, encompassing events like Black Friday and Singles Day, presents a pivotal opportunity for retailers to boost profits through strategic promotional efforts. As the market matures, focus shifts to optimizing the final mile of delivery, aiming to improve efficiency and reduce costs. This project seeks to explore tailored strategies for final mile optimization in Company X, aligning with the broader goal of enhancing efficiency and customer experiences in South Africa's growing e-commerce sector. Despite being the second-largest wholesale food distributor in South Africa, Company X experienced significant on-time delivery performance declines, particularly in its discount retailer brand, Banner 3. The analysis identified logistical bottlenecks in the final mile as the primary contributor to these challenges, resulting in an average delay of 4.3 days in the order fulfilment process. Additionally, the study highlighted the importance of addressing these challenges to maintain customer satisfaction, loyalty, and competitiveness in the rapidly evolving South African e-commerce landscape. This study employs a comprehensive framework and systematic approach to investigate the research questions and objectives. A qualitative research design involves one-on-one interviews conducted digitally via Microsoft Teams. Ethics clearance (MIAEC 099/23) was obtained, ensuring transparency and participant understanding. The sampling strategy prioritizes quality over quantity, with six diverse participants selected to provide rich qualitative data. Data analysis follows Braun and Clarke's thematic analysis approach, incorporating triangulation methods and emphasizing thorough documentation to ensure validity and reliability. This research has thoroughly investigated Company X's final mile delivery challenges during the Golden Quarter, providing comprehensive insights and recommendations for enhancement. Key findings underscore the significance of accurate forecasts, planning collaboration, proximity to customers, fleet and technology utilization, customer service levels, and delivery types in optimizing delivery performance. Recommendations encompass advanced forecasting models, collaborative planning efforts, tailored customer promises, technological enhancements, and automation to address identified challenges and capitalize on opportunities for improvement. The proposed strategies offer a strategic roadmap for Company X to enhance efficiency, customer satisfaction, and competitiveness in the e-commerce landscape, aligning with the study's objectives and concluding the project successfully. The tailored recommendations contribute valuable strategies for improving efficiency, customer satisfaction, and competitiveness. Future research could focus on evaluating the implementation of these strategies and exploring emerging technologies to further optimize the delivery process and adapt to evolving market dynamics.Item The Effects of Rectilinear Acceleration and Deceleration on Shock Formation near a Stationary Boundary(University of the Witwatersrand, Johannesburg, 2024) Morrow, Sean RobertInspired by the world land speed record vehicles the Thrust and Bloodhound supersonic cars (SSC), the focus of this dissertation is to investigate how rapid acceleration affects the formation of shock waves coming off an object travelling in ground effect. Due to the proximity of the ground, these shock waves are not able to freely propagate under the object and must interact with, and reflect off, the ground. Steady state and transient models of aerofoils, accelerating from Mach 0.05 to Mach 2.00 at a test run acceleration of 3 g and an extreme acceleration of 176 g are developed and compared to reveal that the transient shock wave development trails that of the constant velocity aerofoil. The main reason for this difference is that the transient flow is unable to fully develop and reach a state of equilibrium. The extreme acceleration allowed even less time for the flow to develop, and the difference in the shock location continuously increased throughout the acceleration. The same difference in shock location was evident when these models were decelerated back down to Mach 0.05. However, the extreme deceleration and increasing difference in shock location drastically changed the transonic and subsonic flow field, especially as flow features and shock waves from the higher velocity flow overtook the model. In each acceleration and deceleration case, the transient flow history effects subsided and the aerodynamic performance from the transient analysis converged with the aerodynamic performance from the steady state analysis. Under acceleration the transient performance converged at a higher steady state Mach number, while under deceleration the transient performance converged at a lower steady state Mach number. As the magnitude of the acceleration and deceleration increased the Mach number at which the results converged shifted to higher and lower Mach numbers respectively. Models with different orientations and ground clearances were also compared against each other and a case at free flight to determine the impact ground effect has on the formations and locations of the shock waves. Increasing ground effect was shown to promote the formation of shock waves under the inverted aerofoil and in general delay the propagation of the bow shock between the model and the ground. Once the bow shock propagations passed underneath the models, the resulting flow field converged with free flight conditions and ground effect no longer had an impact on the supersonic aerodynamic performance of these models. Under some conditions, the combination of ground effect and the transient effects of acceleration or deceleration can cause dangerous lift and pitch conditions.Item Characterisation, Modelling, Finite element analysis, and optimisation of hyperelastic materials for Non-Pneumatic Wheels(University of the Witwatersrand, Johannesburg, 2024) Bhartu, Saahil; Pietra, FrancescoThis abstract concludes the exploration of hyperelasticity within the context of mechanical engineering. Through this section, we have delved into the substantial elastic deformations characteristic of hyperelastic materials, their capacity for energy conservation during deformation, and their inherently non-linear behaviour. The calibration of non-linear material models has been informed by a rigorously designed experimental regimen, where preferred methodologies and necessary precautions were identified to ensure the integrity of the data obtained. Theoretical foundations for the development of constitutive models have been established, with a discussion of prevalent models frequently employed in engineering applications. Practical modelling applications introduced have provided a tangible context for the utilization of hyperelastic material models. While our focus was predominantly on nearly or fully incompressible materials, foundational concepts for compressible behaviour were also addressed, setting the stage for further investigative pursuits. Polyurethane (PU) materials exemplify hyperelastic behaviour. Through computational simulation, we assessed the deformation in a structured wheel to be 4.6mm, utilizing a 9;5 and 2 parameter Mooney-Rivlin model for the PU material. Experimental testing was conducted measuring deformation to be 4.1mm From the results, the deformation patterns, stress distributions, and contact pressures were analysed, indicating the wheel’s ability to endure a contact pressure of 7.36MPa, deformation of 4.6mm, Von-Mises stress of 3.9MPa. This investigation not only corroborates the distinctive properties of hyperelastic materials but also illustrates how analysis results can inform and optimize design iterations. It demonstrates the practical applications of hyperelastic material models in design engineering, providing a comprehensive understanding that is indispensable for the modelling and analysis of hyperelastic components.Item The assessment of exploration processes in the Upstream Industry to increase exploration efficiency and promote accelerated drilling decisions.(University of the Witwatersrand, Johannesburg, 2024) Tshikovhi, Rilwele Mikovhe Muditambi; Botha, A.During petroleum exploration, petroleum companies (operators) require efficient hydrocarbon detection and delineation methods to locate petroleum prospects and promote drilling (Selley, 1998). The two pre-drill surveys under investigation in this study are seismic surveys and controlled source electro-magnetic (CSEM) surveys which are used to study the subsurface during offshore petroleum exploration. Drilling dry holes is inevitable, however, a proper and thorough prospect evaluation can significantly increase the chance of success of a prospect (Milkov & Samis, 2020). The purpose of the research is to evaluate seismic and CSEM surveys as secondary hydrocarbon detection tools used to recommend drilling, and to also determine if any of these methods can encourage accelerated drilling decisions and significantly reduce exploration risk. A total of 49 seismic-based samples and 41 CSEM-based samples were used in the study. Survey anomalies were assessed against drilling results to determine the predictive strength of each survey. The Chi-test confirmed that there is a significant association between survey anomalies and attributes such as well results, predictive strength, fluid type and trap style. The researcher analysed the two datasets to determine the probability of an anomaly in each survey and the chance of success if each well is drill based on these surveys. The presence of an anomaly was defined as a positive anomaly (PA) and the absence of an anomaly was defined as a negative anomaly (NA). Fluid type and trap style were used to analyse the predictive ability of the survey anomalies. Seismic and CSEM surveys have indicated a high probability of discovering charged reservoirs in a structural trap as compared to stratigraphic traps, however, CSEM is slightly better than seismic surveys in defining these reservoirs. Both surveys have a low probability of predicting a charged stratigraphic reservoir, although seismic surveys have indicated higher chance of success as compared to CSEM. Positive anomalies observed in both surveys proved to be good indicators of gas-bearing reservoirs as compared to other hydrocarbon fluid. CSEM has a slightly higher chance of predicting oil than seismic surveys. A simplified process mapping for the current offshore exploration processes was conducted. A decision tree was used to analyse seismic and CSEM surveys as secondary tools with emphasis given to their hydrocarbon detection capabilities. Bayesian Theorem was used to calculate the posterior probabilities given that a well is drilled on a positive iii anomaly. The same was applied for wells drilled on negative anomalies. The results have indicated that CSEM has a higher probability of detecting hydrocarbon accumulations as compared to seismic surveys.Item Investigating the impact of Railway Signalling Performance on Railway Operations & Performance in South Africa(University of the Witwatersrand, Johannesburg, 2024) Naidoo, Pranell; Sunjka, BernadetteThe South African railway was once an attractive and thriving industry, serving as a catalyst for socio-economic growth and opportunities (George, Mokoena and Rust, 2018). However, in the past decade, the South African freight rail service has become uncompetitive, unreliable, and ineffectively integrated to other modes of freight transportation (The World Bank, 2023). Railway signalling systems are a vital component of the rail network as it ensures that trains travel safely and the rail network is operating at optimal capacity (Zhang et al., 2021). This research focuses on investigating the critical factors contributing to poor railway signalling performance in South Africa, and the impact that these risk factors have on the performance of railway operations, safety and the organization. A critical literature review revealed a gap in the knowledge and understanding of the systemic factors contributing to poor signalling performance. In the effort to close this literature gap, a holistic approach was adopted to develop a conceptual framework which presented factors identified from literature which affects the performance of railway signalling systems. This research adopted a qualitative research approach to achieve the objectives of this research. Semi-structured interviews were conducted with railway signalling and operations professionals. Thematic analysis was used to identify emergent themes from the collected data. The findings identified several factors contributing to poor signalling performance, some of the major identified factors were theft and vandalism, loss of critical skills, lack of investment and budget, managerial issues, ageing infrastructure, inadequate maintenance, human factors, etc. The research findings concluded by outlining the recommendations for future research to address theft and vandalism through collaborative strategies and initiatives, obtaining investments through public-private partnerships, addressing the skills shortage through effective skills retention programs, upgrading the freight rail signalling systems, optimizing the maintenance philosophy, and expanding the research into the passenger rail network to improve railway signalling systems in South Africa.Item An analysis of factors leading to the production of defective wagons in Transnet Engineering(University of the Witwatersrand, Johannesburg, 2024) Nemakhavhani, Pfananani Thelma; Dewa, Mncedisi TrinityRail manufacturing industries play a crucial role in many countries by developing cost-effective transportation solutions to move freight more efficiently. To date, the industry has seen the implementation of traditional quality management practices that are critical in driving efficiencies and better-managed operations to improve the quality of their freight wagons. Despite the conventional quality management techniques, the rail industry continues to manufacture defective rolling stock due to design changes, errors and omissions, and inadequate skills. Over the past few decades, industry and academia have identified various factors contributing to rolling stock manufacturing defects. Nevertheless, which factors were predominantly responsible for the defective wagon production at the Transnet Engineering (TE) Bloemfontein factory remained unclear. Identifying the most prevalent causes of defects is essential in addressing the organisation's quality issues. The primary purpose of this study was to gain insights into the root causes of the defects and recommend strategies to minimise them. The study used an interpretive methodology to identify the root cause of defective wagons produced at TE. Data was collected using purposive sampling. Ten experienced TE employees actively engaged in freight wagon manufacturing were selected for face-to-face interviews. During the research study, the interviews were conducted with the employees using a semi-structured format that allowed for open-ended questions. Investigative techniques, such as cause-and-effect diagrams and the Five "Whys" root cause analysis tool, were used to investigate defects' root causes on the customer complaints register. Additionally, thematic analysis was applied to thoroughly analyse the interviews conducted with the employees, which allowed for a deeper understanding of the issues at hand. The findings showed that inadequate skills, human errors and omissions, a lack of quality culture, time constraints, management's failure to enforce accountability, and poor workshop maintenance/machinery all contribute to defective wagon production. The research provided recommendations, including adopting innovative technology and skills transfer programs to enhance the company's quality management practices.Item Understanding the challenges of implementing an effective Requirements Analysis process within an engineering R&D environment(University of the Witwatersrand, Johannesburg, 2024) Lydall, Peter Wykeham; Law, CraigRequirements Analysis is widely regarded within the Systems Engineering community as an activity that has a significant impact on project outcomes. However, it is an activity that is often overlooked or poorly executed. This report details the application of Yin (2003)’s Case Study Method to a single case, involving an engineering research and development group at a South African science council. The case study attempted to gain insights into the perceptions and attitudes of engineers and managers towards Requirements Analysis, that might explain why it is performed inconsistently or less effectively than it could be. Key findings include: that there is a poor understanding of what Requirements Analysis is; the importance of assigning a Requirements Analyst, in a dedicated role, with the appropriate level of engineering experience and Systems Engineering training, and a desire to perform the activity; the necessity of having a cost effective and tailored process which evolves over time.Item Assessment of Quality Management in Major Projects in the Mining Industry in Botswana(University of the Witwatersrand, Johannesburg, 2024) Pitswe, Odirile Boniface; Sunjka, BernadetteWhile project performance is generally evaluated in terms of schedule, cost and quality performance, guidelines for project quality management are lacking, (Steyn and Nicholas, 2008). The Botswana mining industry is faced with problems of engineering projects which don’t meet the expected outcomes and most of the problems emanate around quality management and quality defects. This research project involved the assessment of quality management in major engineering projects in the Botswana mining industry by evaluating the level of adoption and implementation of quality management systems in major engineering projects, identifying the major causes of project failure, and evaluating the effectiveness of quality management system as employed in major capital projects. The research was focused mainly on Debswana Diamond Mining company as the major mining house in the country, with an objective to assess the maturity level of the company’s quality management system (QMS) and identify opportunities for improvement. A mixed method approach was used which involved archival research and survey research, the results of which were triangulated to corroborate the findings and remove bias. Archival research was conducted using the company document repository to review project retrospect reports, (Lessons learnt reports) and identify problems experienced during the implementation of different projects. These were correlated with common causes of project failures as identified in the critical literature review and cross referenced against survey results to further confirm them. The results indicated that the maturity level of the Quality Management system is at level 4 (quantitatively managed), where processes are measured and controlled. Gaps were identified that if rectified would move the maturity to level 5 (optimizing), where the focus would now be on process improvement. The gaps are mainly around operationalisation, lower-level employees training on quality management, optimisation of shared resources especially subject matter experts like project engineers, key stakeholder management, involvement and participation from end users and operational teams. The study came up with the top five (5) major causes of project failure being: 1. Shared resources and subject matter experts get overstretched between different projects and end up neglecting quality assurance. 2. Poor stakeholder management. 3. Lack of stakeholder involvement and participation in the project. 4. Inexperienced project team. 5. Unclear statements of expected quality outcomes.Item A report on the investigation into factors that impact the replication of operational excellence programs across the global operations of a top global mining company: The Case of Rio Tinto(University of the Witwatersrand, Johannesburg, 2024) Tsomole, Moleboheng; Sunjka, BernadetteAchieving operational excellence in mining is fraught with challenges, including the lack of standardized procedures, misalignment with company strategy, and cultural disparities across global operations. This study investigates the strategies for efficient deployment of operational excellence programs, with a focus on Rio Tinto’s operational excellence framework, RTSPS (Rio Tinto Safe Production System). A mixed-methods approach was adopted, integrating qualitative data from semi-structured interviews with Rio Tinto managers and employees and an analysis of secondary data from company reports. This study combined deductive and inductive research approaches to provide a comprehensive exploration of operational excellence at Rio Tinto. The deductive approach involved testing specific hypotheses drawn from existing literature on operational excellence programs, such as the assumption that standardized systems like RTSPS would encounter difficulties in culturally diverse environments. Inductive reasoning complemented this by allowing themes and insights to emerge directly from empirical observations during interviews, thus offering an authentic view of the challenges and successes of RTSPS deployment. The qualitative component of the study was centered around 14 semi-structured interviews with key stakeholders across various regions, including operational excellence managers and improvement leads. These interviews were conducted virtually using platforms like Microsoft Teams and Zoom, enabling broad participation across geographically dispersed sites. The interview questions were meticulously crafted using Wengraf’s pyramid model, which starts with Critical Research Questions (CRQs) that are broken down into Theoretical Questions (TQs) and further refined into specific Interview Questions (IQs). This structured approach ensured that the interviews remained focused on uncovering detailed insights into operational challenges and strategic alignment. The questions were adapted to account for the contextual nuances of each participant's operational environment, and particular care was taken to avoid leading questions, thereby minimizing researcher bias.The analysis of data employed thematic coding, revealing key insights into behavioural adaptability, cultural diversity, and the influence of leadership on the adoption of standardized processes. Themes were generated from the qualitative data and cross-referenced with secondary data sources, including integrated annual reports that provided a broader organizational context and corroborated the findings. Secondary data analysis allowed for a deeper understanding of Rio Tinto’s strategic objectives and how these aligned or conflicted with ground-level practices. Using qualitative data from interviews with 14 participants, the research highlights key themes identified through thematic analysis, focusing on the complexities of implementing RTSPS across diverse cultural and operational landscapes. Sentiment analysis conducted via ATLAS.ti software provided additional insights into participants' attitudes and emotional responses, shaping the creation of a comprehensive codebook that guided systematic data analysis. The findings reveal that RTSPS faces significant deployment challenges, including the integration of a standardized system across culturally varied sites, a need for a more people-centric approach, and issues with communication, resource allocation, and adaptability. Participants with experience outside of Rio Tinto provided unique insights into alternative deployment strategies that could enhance replication and adaptability across different industries and operational settings. The study also identifies the foundational elements critical to RTSPS, such as standardized processes, robust training programs, and a centralized knowledge- sharing infrastructure. These components were highlighted as essential for fostering a culture of continuous improvement and ensuring successful replication across Rio Tinto’s operations. Rio Tinto's annual reports from 2018 to 2022 emphasize RTSPS's role in enhancing safety, efficiency, and sustainability, with impacts on the triple bottom line of people, planet, and profit. However, the challenges identified through this research include cultural integration, resource constraints, and the need for local adaptability, mirror broader issues documented in the literature on operational excellence in the 7 mining sector. The study concludes that while RTSPS holds significant potential, its success hinges on balancing standardization with the flexibility to accommodate local conditions and prioritizing employee engagement throughout the deployment process.