Browsing by Author "De Wet, Pieter"
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- ItemA cellular automation model of Eldana saccharina Walker infestation in sugarcane to improve the spatio-temporal planning of sugarcane planting and harvesting(Stellenbosch : Stellenbosch University, 2020-12) De Wet, Pieter; Potgieter, Linke; Stellenbosch University. Faculty of Economic and Management Sciences. Dept. of Logistics. Logistics.ENGLISH SUMMARY : Farmers are being increasingly challenged to use management techniques that reduce the negative impacts of farming. One of the main areas where the environment is negatively impacted by farming practices is pest management when using chemical pesticides. The manipulation of harvesting schedules has long been recognised to impact pest populations in agricultural crops and plays an important role in establishing an integrated pest management (IPM) system. In this study, the impact of di erently con gured sugarcane agricultural landscapes in terms of crop age, and the resulting di erent harvesting times, on the infestation dynamics of Eldana saccharina Walker, were considered. The dynamics of Eldana saccharina Walker infestation in sugarcane were simulated using a cellular automaton approach. The main objective was to identify generic eld con gurations (in terms of crop age) where infestation levels are minimised, and subsequently sucrose yield was maximised. The results obtained indicate that larger groupings of same aged crops tend to provide higher sucrose yields, compared to con gurations where many same aged small elds were scattered across the landscape. It was also determined that harvesting spread over the entire harvesting season with various aged crops tended to outperform scenarios with bulk harvesting of crops only at certain times during the harvesting season. In addition, an earlier harvesting age was found to be better, indicating that if possible, sugarcane should not be carried over during the period when sugarcane mills are closed.
- ItemInvestigating the effect of non-assembled product kits on the resource efficiency of process chains(Stellenbosch : Stellenbosch University, 2017-12) De Wet, Pieter; Oosthuizen, G. A.; Stellenbosch University. Faculty of Engineering. Dept. of Industrial Engineering.ENGLISH ABSTRACT: In order for manufacturing suppliers to stay competitive in the global market, innovative and resource-efficient process chains need to be a part of the manufacturing strategy. Global megatrends are macroeconomic and geostrategic forces that shape our world. Thus, the manufacturing industry must adapt to benefit from these opportunities or risk being left behind. These rapid advancements are changing the way in which we approach the manufacturing of products. The nature of products, the change in consumer demand, the economics of production and the economics of the supply chain have led to a fundamental shift in the way that companies do business. There is an increased demand for customisation and personalisation from customers. IKEA is one example of a company successfully benefitting from the use of non-assembled product kits and do-it-yourself (DIY) products. The ‘IKEA effect’ shows that people tend to place more value on products that they created themselves, even if these products are mundane and not unique; customers are satisfied if the products are fun to build, or customised. A firm’s competitive advantage is sustained only by transforming its resources into customer-valued products, services and DIY experiences through various operational capabilities. Therefore, the aim of this research was to investigate the effect of non-assembled product kits on the resource efficiency of process chains. The research objectives included the design of a framework to determine this effect on the process chain as well as determining the advantages and disadvantages of using non-assembled product kits. Case studies of IKEA furniture, Dell computers and bamboo bicycle kits were used to understand the market for non-assembled product kits. This information was used to develop a framework to be used by companies to determine the impact of incorporating non-assembled product kits on the resource efficiency of their process chains. A bamboo bicycle was manufactured to aid in the development of equations to be used by the framework. A titanium satellite was manufactured and used as a validation study to determine the accuracy of the framework. The results were compared to traditional products and illustrated by using graphs that showed the comparison in terms of cost, time, waste, quality and energy consumption. The results illustrate that the use of non-assembled product kits has more advantages than selling fully assembled products. The value chain for non-assembled product kits has an impact on every stage of the traditional value chain. The newly developed framework illustrates the effect of converting an existing product to a non-assembled product kit. The results are not a specific value but give the investigating company an indication of the effect of using non-assembled product kits on the resource efficiency of the given process chain for its product. A bamboo bicycle was validated and showed a decrease of 24% for the total manufacturing time. The only setback being the 30% decrease in quality control due to the assembly step being outsourced to the customer.