Masters Degrees (Industrial Engineering)
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- ItemAn integrated analysis of the flow volumes, conditions and cold storage capacities in the South African citrus supply chain.(Stellenbosch : Stellenbosch University, 2024-03) Bulterman, Stuart; Louw, Louis ; Berry, Tarl; Stellenbosch University. Faculty of Engineering. Dept. of Industrial Engineering.ENGLISH ABSTRACT: The South African citrus industry is expected to grow another 33% over the next 6 years and is defined as the second-largest exporter of fresh citrus globally. Ultimately, the supply chain that facilitates this flow has various processes throughout it, and the perishable nature of citrus means that the underlying timelines and conditions are of the utmost importance for the success of the industry. The overall quality of the fruit is ultimately a function of time and temperature, which are currently unknown variables. Additional cold stores are extensively utilised to reduce fruit degradation and ensure proper phytosanitary measures. While prior research has provided excellent examples of individual sections of the supply chain, effects of certain sections, or a general capacity overview, there is no specific study that brings together all of these disparate elements to create a holistic supply chain overview. As such, using a pragmatic mixed methods approach, the problem of defining the various stages of the supply chain, the underlying conditions, timelines, their effects, and the overall ability of the industry to export was embarked upon. Ultimately, the golden thread that runs through this research is the interconnectedness of all the individual processes, which is what ultimately defines an industry and its supply chain. Although citrus is a winter crop, the regions in which it is grown throughout South Africa mean that there is significant temperature variability during the harvest of fruit, with temperatures in excess of 28 °C at harvest. This is then combined with on-farm dwells lasting 1-2 days, which have a significant impact on fruit quality, with fruit losing upwards of 5 days of shelf life on the farm alone. Ultimately, this is having cumulative effects throughout the supply chain, as fruit progresses, taking 10-15 days before being loaded into a container and then an additional 20-40 days before arriving at the destination, with losses estimated to be upwards of 6% of all shipments. The additional growth is likely to add additional capacity constraints within the industry, with severe capacity constraints forecasted to occur by 2026 without additional cold storage capacity. Regulatory requirements may add an additional burden in the coming years, as fruit destined for the European Union has to undergo additional cooling. As such, the industry will likely have to invest R 1.7 billion (11% of its gross value) over the next 5 years to ensure sufficient cold storage capacity. The findings of the research show that the coming years will present significant hurdles within the South African citrus industry, requiring targeted and pragmatic interventions to ensure the continued profitability and success of the industry as a whole.
- ItemTowards simulating the South African fresh fruit export supply chain(Stellenbosch : Stellenbosch University, 2024-02) Schoeman, Lente; Nel, Stephan; Searle, Christa; Van Eeden, Joubert; Stellenbosch University. Faculty of Engineering. Dept. of Industrial Engineering.ENGLISH ABSTRACT: Climate change has become one of the, if not the most, pre-eminent environmental issues threatening the human population and natural ecosystems. The extent of greenhouse gases emitted, mainly due to burning fossil fuels, has drastically increased due to the onset of successive industrial revolutions, increasing the likelihood of irreversible consequences. The greenhouse gas emissions of logistics processes and supply chain activities account for the majority of companies' overall greenhouse gas emissions and carbon footprint. Most of these emissions are engendered by logistics activities related to transportation. In particular, global food supply chains face amplified challenges due to their reliance on fossil fuels, exacerbated by volatile fuel prices, heightening vulnerabilities in transportation and distribution components within supply chains This dependence showcases the increasing importance of understanding, quantifying, and better managing carbon emissions related to transport logistics activities within supply chains The carbon emissions from transportation logistics vary among supply chains and can be attributed to various factors. Given the perishable nature of food products especially fresh fruit, the transportation sector can have a significant impact on the food supply chain, as these goods often require long-distance shipment primarily via road, especially so within South Africa (the main case study of this research project). Furthermore, the distribution of fresh fruit necessitates temperature regulation throughout the process, leading to a higher rate of energy and fuel consumption when compared with non-perishable goods. Notable factors and trends contributing to fuel consumption such as the transport mode, vehicle attributes, driver behaviour, environmental factors, and operations ought to be considered when attempting to reduce the environmental impact of transportation activities. There is, however, a trade-off in respect of minimising cost and reducing carbon emissions — managing the financial implications associated with adopting sustainable practices and technologies is widely regarded as a complex endeavour. Within the context of South Africa, the citrus industry is a vital component of the country's In this thesis, an agent-based simulation model of the real-world transportation conditions and decisions within the context of the South African citrus export supply chain is developed towards helping to address the aforementioned challenges This approach incorporates the use of various frameworks and resources to aid in model development. The proposed solution methodology involves data collection and analysis to gather information relating to the current transportation system, including geographical locations of facilities, truck types, and associated costs. An agent- based model is developed, representing key entities such as production regions, packing facilities, cold storage facilities, and the port of export. Each entity is represented by agents with specific attributes and behaviours, including transportation preferences, capacities, and consolidation strategies. Carbon emission calculations are integrated into the model to estimate emissions for different transportation conditions and decisions (referred to as scenarios) considering factors such as fuel consumption, driver behaviour, and truck types, to name a few. Cost reduction simulations are conducted to evaluate financial impacts and identify cost-effective solutions, accounting for fuel costs, and potential savings from consolidation. The agent-based model is formulated in the Any Logic Simulation Software environment enabling valuable visualisation of the physical movement of agents and graphical representations of cost and carbon intensity associated with different scenarios, during which predefined metrics such as carbon emissions, transportation costs, and logistical efficiency are compared. Based on the simulation results, recommendations are generated so as to provide decision support. These recommendations include adopting specific truck types, driver incentives, implementing consolidation practices, and suggesting modifications to the transportation network to achieve sustainability goals while balancing economic considerations. agricultural sector and has a significant economic impact. It is one of the largest citrus exporters globally, supplying fruits to numerous international markets. The South African citrus export supply chain relies heavily on road transportation to move citrus fruits from production regions to packing facilities, cold storage facilities, and export ports posing challenges related to the reduction of carbon emissions and the improvement of cost-effectiveness.
- ItemDeveloping a selection and evaluation packaging framework for retail supply chains: a South African retail supply chain case study(Stellenbosch : Stellenbosch University, 2024-02) Lubbe, Nikola; Van Eeden, Joubert; Stellenbosch University. Faculty of Engineering. Dept. of Industrial Engineering.ENGLISH ABSTRACT: Packaging has undergone a transformation, shifting from a supporting role to a key strategic element that impacts all aspects of modern supply chains. With products now traveling globally, the need for a structured process to select and assess packaging is evident. Packaging systems play a vital role in logistics, involving various resources. Current industry trends show a shift towards optimizing packaging supply chains to enhance logistics and environmental performance. This emphasizes the importance of effective collaboration between packaging systems and supply chain stakeholders to achieve superior supply chain performance and gain a competitive edge. This thesis focuses on developing a structured framework for selecting, evaluating, and implementing packaging solutions in retail supply chains. The framework aims to reposition packaging as a strategic element in the supply chain. The study employs a systematic approach to review existing packaging frameworks and identifies five relevant ones. Design requirements were extracted through surveys, interviews, and field observations and cross-referenced with specific existing packaging frameworks and utilized as input toward the framework development phase. The framework development phase outlines a structured process with six steps: identifying stakeholders, clarifying the packaging role, selecting evaluation criteria, weighting, and rating criteria, assessing environmental and cost impact, and testing and reviewing the packaging system. Each step provides clarity on input, action, and output, ensuring that the framework can be easily understood and implemented. A three-phase validation process verified the framework's comprehensiveness, adaptability, and effectiveness. The research concludes that the proposed framework effectively fills gaps in existing frameworks while maintaining flexibility for measurement inclusion or modification. It solidifies the framework's merit to be considered alongside packaging frameworks in the literature. This research contributes to the packaging industry by providing a comprehensive and adaptable framework that redefines packaging as a strategic component within the supply chain, promoting informed decision-making and addressing environmental and cost concerns.
- ItemDevelopment of Ti6Al4V-Cr3C2 metal matrix composites using selective laser melting(Stellenbosch : Stellenbosch University, 2024-03) Nkosi, Nompumelelo Venessa; Sacks, Natasha; Stellenbosch University. Faculty of Engineering. Dept. of Industrial Engineering.ENGLISH ABSTRACT: The manufacturing of titanium alloys and metal matrix composites (MMCs) using selective laser melting (SLM) has seen a rapid growing trend over the years. This is due to the developing manufacturing technologies and the demand of attractive and improved engineering components for industrial use in aerospace, medical, and automotive sectors. The dual α-β phase titanium alloy; Ti6Al4V has found its great application in the manufacturing of turbine blades and engine components in aerospace due to its high lightweight-to-strength ratio and good combination of properties. There is always a need to further improve these mechanical properties and performance, hence the concept of the addition of metal carbides to the Ti6Al4V matrix which studies have found to have a great strength hardening effect and results in an increase in the specific strength of the composite, thus increasing the component’s life span. This study focuses on the feasibility of manufacturing metal matrix composites of the Ti6Al4V matrix reinforced with chromium carbide (Cr3C2) using selective laser melting. A scoping review was conducted to evaluate the status of SLM and its application in the manufacturing of titanium MMCs using metal carbides and it was found that the most used carbide was TiC due to its compatibility with Ti6Al4V and its attractive properties. It was also reported that the main influential SLM processing parameters were the laser power, hatch distance, scan speed and the scanning strategies which all played key roles in determining the quality of the parts. These studies were then used to choose Cr3C2 as a reinforcing material due to the high hardness, corrosion and wear resistance and comparable low density as compared to other commonly used carbides. In addition to this, Cr3C2 is a grain refiner, therefore this property aids in improving the Ti6Al4V properties using grain refinement mechanisms and since chromium is a beta stabilizer, it’s addition to Ti6Al4V will lead to the improvement of the ductility and toughness of the final MMC. The design thinking problem solving approach was used to carry out the experimental methodology. Powder characterisation for the feedstock powders was conducted to determine the flowability, apparent density, morphology, particle size and composition. The Ti6Al4V alloy samples were initially printed using the SLM machine optimised parameters, characterised and the mechanical properties were used as benchmark for the addition of the Cr3C2. Two compositions of Cr3C2 (5 wt% & 10 wt%) powders were added to the Ti6Al4V powder to make individual mixtures that were used as feedstock for SLM. The design of experiment planning was used for SLM parameter optimization of Ti6Al4V-Cr3C2 whereby the parameters were tailored, and the response of the prints was evaluated. The effect of the scanning strategy, laser power, scanning speed and hatch distance on the density, microstructure, hardness, and tensile behaviour was studied, and the optimal conditions were determined for the compositions to obtain crack-free Ti6Al4V-Cr3C2 composites. The optimal composites were heat treated and the hardness, microstructure and tensile properties were compared with as-built Ti6Al4V properties to evaluate the effect of the annealing heat treatment.
- ItemA maturity model for data science in small and medium-sized enterprises from developing countries(Stellenbosch : Stellenbosch University, 2024-02) Rautenbach, Simon; De Kock, Imke; Grobler, Jacomine; Stellenbosch University. Faculty of Engineering. Dept. of Industrial Engineering.ENGLISH ABSTRACT: Data science (DS) is an industry 4.0 (I4.0) technology with the potential to improve organisational decision-making through the use of insights previously unknown, which may provide a competitive advantage to an organisation. Small and medium-sized enterprises (SMEs) are known to be large contributors to economies across the globe, based on metrics such as the gross domestic product (GDP) and the total share of the workforce. SMEs are generally less inclined to implement I4.0 technologies due to various challenges, such as a lack of capital and skills, which is detrimental to their development and competitive advantage. It can be argued that the successful implementation of DS has the potential to improve organisational decision-making in SMEs and increase their competitive advantage. A semi-structured literature review was conducted to explore the different I4.0 technologies, along with SMEs and how they fit into economies across the globe. A structured literature review was then performed to contextualise the problem, and to understand the factors that influence the successful implementation of DS in SMEs — both from developing and developed countries. Several challenges and opportunities associated with the implementation of DS were identified. Furthermore, a lack of research products in literature that address these challenges was identified, especially within the context of developing countries. The aim of this research was thus to contribute towards the successful implementation of DS in SMEs from developing countries. A requirement specification chapter revealed that a maturity model would be the most suitable research product for this study. Maturity models are designed as tools that enable the user to measure the current state of maturity for various domains within an organisation. Consequently, this study investigated the use of a maturity model as an appropriate research product for the implementation of DS in SMEs from developing countries. In pursuit thereof, the data science maturity model for SMEs (DSMMSMEs) was developed. The model consists of five domain components, which may be viewed as high-level categories of the given domain, which is DS for the purpose of this study. The chosen domain components are data, infrastructure, people, management, and governance. The DSMMSMEs was developed based on a foundational knowledge of current literature, which consists of various maturity models and research pertaining to DS and SMEs from developing countries. The development of the model followed a rigorous methodology for maturity model development, which is widely accepted across literature. Therefore, this research may be described as a non-empirical, qualitative study, consisting of both inductive and deductive approaches in an investigative manner. Once the DSMMSMEs had been developed, it was subject to a verification process which consisted of subject matter expert interviews. The feedback from the interviews was used to develop a second iteration of the model, which addressed any concerns raised by the subject matter experts. Next, the model was subject to a validation and implementation stage, which evaluated the appropriateness in terms of applicability, practicability, and usability. The findings of the implementation and validation stage showed that the DSMMSMEs is an appropriate tool that may contribute towards the successful implementation of DS in SMEs from developing countries.