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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Designing optimisation of a cane haulage vehicle.

Cowling, Simon L. January 2008 (has links)
The sugar industry transports in excess of 20 million tons of sugarcane per annum, equating to approximately 800 000 road consignments. This entails substantial expenditure on vehicle capital and operational costs. There exists substantial scope to redesign vehicle configurations to reduce the vehicles tare mass and optimise the process of cane transportation. These modifications could potentially save the industry approximately Rl36 million per annum, and in addition will increase a vehicles lifespan, performance and speed. This project is one aspect of a larger project organised by the South African Sugarcane Research Institute, with the general aim of optimising the entire sugarcane transportation system. Aspects of this particular project include literature research as well as field investigation into the various sugarcane transportation systems in South Africa and throughout the world. The design of a cane haulage vehicle will be analysed and optimised, using tools such as finite element analysis. The aims of this project include the investigation of the engineering design issues with respect to vehicle/trailer configurations, and the design of an optimised cane haulage vehicle which increases the efficiency of raw sugarcane transportation in South Africa. / Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2008.
2

An investigation into sugarcane vehicle loading with respect to influences on overall transport efficiency.

Moodley, Samantha. January 2011 (has links)
The South African sugar industry ranks eleventh in size out of 200 sugar-producing countries; and continuous advancement is essential to ensure that this industry remains competitive. The transfer system from field to mill, includes sugarcane being moved, loaded, transloaded and off-loaded and amounts to more than 25 % of the total production cost of sugarcane, hence small adjustments can have significant economic benefits. Payload variability is a current problem making the loading operation a leverage point for improvement. As a consequence of poor management and the under-utilisation of equipment, loading has been identified as an inefficient and costly operation. Studies have shown that technology and management can contribute to improved loading accuracy. This study aimed to evaluate loading characteristics in an attempt to develop guidelines for loading. Whole-stick loose sugarcane, which is loaded with grabloaders, is common practice in South Africa and this study aims to improve this loading system. This was achieved by reviewing transfer systems worldwide and synthesising the sugarcane characteristics that drive the designs and the management of equipment and systems within the transfer system. The sugarcane characteristics include the sugarcane bulk density, the length, the diameter and other variety characteristics e.g. the degree of lodging. Other factors, such as the preparation method for loading, the harvesting method and the topography, also have a marked influence on the efficiency of the transfer system. An assessment of typical South African loading practices was undertaken to establish beneficial practices and current operating rules. These factors included the way in which the sugarcane was presented prior to loading, as well as the techniques adopted for loading. The results were used to generate practical recommendations for the improvement of the loading component in order to make the transfer system more efficient. An efficient system comprises a balance of high quality operations with respect to safety, accurate loading, reduced cycle time, optimal fuel usage, reduced roadside losses, reduced sugarcane damage and increased off-loading efficiencies. An investigation into consignment characteristics was also carried out to identify the factors that need to be considered during the loading operation. These factors included the sugarcane bulk density, the degree of sugarcane alignment and the design characteristics of various vehicles. A set of practical guidelines were created from this study. / Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2011.
3

An integrated sugarcane supply chain model : development and demonstration.

Stutterheim, Peter. January 2006 (has links)
The South African sugar industry is a large industry which relies on expensive capital equipment to harvest, transport and process sugarcane. An average of 23 million tons of sugarcane are annually supplied to 14 mills from over 2 000 large-scale commercial growers and 48 000 small-scale growers. Supply chain stakeholders can benefit if operations are successfully streamlined. Computer-based mathematical models have been used in other industries to improve supply chains, especially in forestry, and are expected to play an increasingly important role in future planning and management. Management of sugar supply chains has historically focussed on generating competitive individual supply chain components. However, inter-component optimisation generally disregards many important intra-component interactions. Hence, efficiency improvements may be significantly limited. Integrated supply chain modelling provides a suitable approach for addressing this problem. The aim of this project was to develop and demonstrate, in concept, an integrated supply chain model for the sugar industry. Such a model could be used to address various integrated planning and management problems throughout the supply chain. A review of existing integrated agri-supply chain models was conducted followed by the development of CAPCONN, an integrated sugar supply chain model framework, that incorporate all steps from field to mill back end. CAPCONN estimates sugarcane quality, mill recovery, capacity utilisation and production costs. Bottlenecks are highlighted and the model could contribute towards capacity manipulation for efficiency improvements under different harvesting scenarios. CAPCONN was demonstrated by analysing a number of scenarios in a mechanisation case study at Komati Mill where sugarcane is currently burned and manually cut. A total of twelve scenarios were compared, including variations in cropping system and time of year. The model framework predicted that a decrease in sugarcane quality and sugar recovery would occur under mechanical harvesting scenarios. Estimated production costs were also higher, even though the transport fleet was significantly reduced. A manually cut green (unburned) harvesting scenario showed a further decrease in sugarcane quality and sugar recovery. Mechanical harvesting during wet weather caused a substantial reduction in supply chain capacity and an increase in production costs. CAPCONN output trends compared favourably with measured and observed data, though the magnitude of the trends should be viewed with caution, since the CAPCONN framework is only a prototype. This shows that it may be a suitable diagnostic framework for analysing and investigating the sugarcane supply chain as a single entity. With further development to a model, the CAPCONN model framework could be used as a strategic planning tool although, one drawback is that a relatively large number of technical inputs are required to run the model. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2006.
4

The feasibility of automatic on-board weighing systems in the South African sugarcane transport industry.

Pletts, T. R. January 2009
Sugarcane hauliers in South Africa have high variations in vehicle payloads, which influence both transport economics and the legitimacy of their operations. Increasing economic pressure due to declining sugar prices and ever increasing fuel prices has invoked interest to improve vehicle utilisation and reduce costs, while complying with the local traffic legislation. On-board weighing technologies, such as on-board load cells, could assist operators to control their payloads more accurately and hence reduce the frequency of both over and under loaded consignments. In this study, an investigation is conducted to evaluate the feasibility of on-board weighing systems in the South African sugarcane transport industry. An overview of on-board weighing systems is presented. The overview gives insight into the technical composition of an on-board weighing system as well as presenting various benefits and drawbacks that are associated with an on-board weighing system. Earlier studies conducted on the use of on-board weighing systems are scrutinised and evaluated and it is concluded from these that vehicle utilisation could be improved, while concurrently reducing the overloading of vehicles. Field research was conducted to evaluate the accuracy and consistency of on-board weighing systems currently being utilised in the sugarcane transport industry as well as to determine the critical factors that influence the effectiveness of the system while assessing if overloading of vehicles was reduced when on-board weighing systems were employed. It was concluded that the systems evaluated were reasonably accurate with mean error being 0.4 tons. The consistency of the systems was good with 75% of all measurement being within 0.5 tons of each other. The critical factors determining the effectiveness of the on-board weighing systems were established as being management of the system as well as cane variety and quality. Overloading was reduced by 9% in one field evaluation and 5% in another. Further reduction can be realised through tighter management of the on-board weighing systems. An economic evaluation of an on-board weighing system was performed using the capital budget method. This method was used to determine the pay off period required to realise the investment into an on-board weighing system for scenarios where the payload is increased by 2, 3 and 4 tons and transport lead distance is 20, 40, 60, 80, and 100 km. The shortest pay off period occurred when the lead distance was 60 km and the time was 1, 2 and 3 years for payload increases of 2, 3 and 4 tons respectively. For lead distances of 40, 60 and 80 km the investment is worthwhile and considerable returns in investment can be realised, however, for the other lead distances the pay off period could be deemed to be too long. From the observation made during the field evaluation together with the literature studied, guidelines for the use of on-board weighing systems under various transport scenarios were formulated and are presented in chapter six. / Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2009.
5

Development of network theory approaches to analyse cause and effect relationships in complex integrated sugarcane supply and processing systems.

Sanjika, Thawani M. January 2013 (has links)
Network theory has been widely and successfully used to model, analyse and visualise complex systems. This study aimed to develop approaches to analyse complex integrated sugarcane supply and processing systems. A literature review includes network theory, complex systems, the Theory of constraints, indicator analysis and root cause analysis. The cause-and-effect networks of four sugarcane milling areas in South Africa; viz. Eston, Felixton, Komati and Umfolozi were developed, where the factors that negatively affected the performance of the milling areas were represented by vertices, the relationships among the factors by arcs and the strength of these relationships by weights. Three network theory based analytical tools namely; (a) primary influence vertex analysis, (b) indicator vertex analysis and (c) root cause vertex analysis were developed to analyse the networks. The results from the analyses indicate variations in the numbers and strengths of primary influence factors, problem indicator factors and root causes of problems between the four milling areas. Rainfall, drought and high soil content in sugarcane were identified as the strongest primary influences in the respective milling areas. High crush rate variability, low cutter productivity, running behind allocation and increases in operating costs were identified as the strongest indicators of poor performance in the respective milling areas. Rainfall was found to be the most dominating root cause of poor performance in all the milling areas. Since the South African integrated sugarcane production and processing system is complex, it is likely that the unique approaches developed in this study can be used successfully to also analyse other relatively complex systems. It is recommended that these approaches be tested within other systems. The main contribution of this study is in the form of a relatively easy-to-use network theory based comprehensive systems analyses tool. This analytical approach has, to the author's knowledge, not been used in any agri-industrial application previously. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.
6

Issues pertaining to cane supply reliability and stockpiling at the Umfolozi sugar mill - model development and application.

Boote, Gordon L. N. January 2011 (has links)
The co-owned Umfolozi Mill area has developed as an integrated supply chain. Cane supply reliability was identified as a potential area for productivity improvement at Umfolozi. It is important that the cane supply to a sugar mill arrives at a steady and reliable rate. A reliable cane supply ensures that the mill can operate at an optimum efficiency. Sugarcane supply reliability depends on how the mill area adapts to unforeseeable changes in the supply chain. An important aspect to this is the weather and how it affects the harvesting regimes. The sugarcane supply chain at Umfolozi is divided into two branches, road transport and tram transport. The trams account for 70 % of the cane delivered to the mill and the can is sourced from a climatically homogenous region. In the occurrence of a rainfall event of above 5 mm, infield harvesting cannot take place on the Umfolozi Flats; hence 70 % of the mill‟s supply is halted for one or more days. To address the problem, a stochastic model was created to simulate the effectiveness of an enlarged cane stockpile if it were maintained on the current tram sidings outside the mill and were crushed when wet weather prevented further harvesting. The stockpile was simulated on a first-in first-out principle and was able to supply the mill with enough cane to continue running for 24 hours. The model was then used to conduct a series of Monte Carlo simulations on which sensitivity analyses and economic feasibility assessments were carried out. Results show that the stockpile was effective in reducing the length of milling season and the number of no-cane stops. However, on further analysis into the implications of creating a stockpile it was found that 1% recoverable value (RV) was lost during the 24-hours that the cane is stored outside the mill. The loss in revenue as a result of the RV reduction had a negative impact on any savings created with the implementation of the stockpile. This result made apparent the negative impact of deterioration to the whole supply chain. Further research is required to determine more accurately the rate of deterioration, and therefore, quantify more accurately the losses that occur in the supply chain. A significant outcome of the study was the development of a mechanistic tool which drove decision making at Umfolozi Sugar Mill. It lead to the development of the modelling framework LOMZI, a simulations based framework which places more emphasis on environmental factors and risks. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2011.
7

A simulation study of cane transport system improvements in the Sezela Mill area.

Giles, R. C. January 2009 (has links)
The South African sugar industry is of significant local and international importance and covers an area in excess of 450 000 hectares. This area yields approximately 21 million tons of sugarcane per annum which is transported almost exclusively by road, from farms to the sugar mills. The industry is under increasing economic pressures to improve its productivity and competitiveness and sugarcane transport in the sugarcane supply chain has been identified as one area where large improvements and associated cost reductions can be made. This is mainly due to the excess in number of vehicles in the inbound transport system, the high relative cost of transport compared to other production costs in producing sugarcane, and the high fixed costs associated with truck fleet operations. A simulation case study of the transport system was completed in 2005 in the Sezela Mill area in which approximately 2.2 million tons of sugarcane is transported per annum over an average distance of 29 km by approximately 120 independently managed vehicles owned by a wide range of hauliers and individual growers. This amounts to an estimated cost of R58 million per annum. This study investigated the potential savings that could occur as a result of a central fleet control system with integrated vehicle scheduling. A scheduling software package named ASICAM, which resulted in significant savings in the timber industry (Weintraub et al, 1996), was applied within the Sezela region. Results suggested that the number of trucks in the fleet could theoretically be reduced by at least 50%, providing that a central office controls vehicle movements and that all hauliers serve all growers in an equitable fashion. In addition, investigations towards decreasing loading times, decreasing offloading times, changing vehicle speeds and increasing payloads by reducing trailer tare mass showed further reductions in the number of trucks required. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.
8

Development of a spatial sugarcane transport infrastructure-planning model.

Harris, A. J. January 2008 (has links)
Due to the significant cost of transport in the sugar industry, a model, named FastTrack, was developed to investigate infrastructure planning opportunities. The model mathematically incorporates road construction and maintenance costs, terrain and land-use maps, vehicle performance specifications and annual sugarcane volumes to determine the most cost effective route, per vehicle type, from a production region to a mill. Route planning using geographical information systems (GIS) is a standard approach for determining the optimum alignment for pipelines, roads and canals. Theory of this approach was reviewed to create a foundation for the development of FastTrack. A small portion of the Noodsberg sugar mill region in the KwaZulu-Natal midlands was selected as a case study area to test the capabilities of FastTrack. A start location was identified as a natural flow point for 70 000 tons of sugarcane hauled from an area south of the mill. Currently this volume is transported along a 9.3 km stretch of national road from the start location to the sugar mill, while the Euclidean distance is approximately 7 km. Three vehicle types, differing in payload, fuel consumption and road speed were assessed. Two common and currently utilised vehicles, the tractor hilo and interlink combinations, were aligned by FastTrack along existing national roads. A financial penalty for driving on national roads was assumed for the third vehicle type considered, land trains, as these are currently not permitted to operate on national roads in South Africa. This high bulk vehicle was selected to test the capabilities of FastTrack and to identify if cost savings could be realised through increased consignment capacity as has been achieved in Australia, Malawi and Brazil. Utilising the model a new and more direct theoretical route was generated for the land train with a length of 7.4 km. Existing farm roads which would require upgrading made up 34 % of this proposed route. An economic analysis was conducted and showed that under current conditions, the private route generated by FastTrack for land train use, would be the most cost effective, with a system cost of R 57.50 t" . The tractor hilo and interlink had system costs of R 59.58 t" and R 60.98 t"1 respectively. Repeating the economic analysis with projected fuel prices indentified that the cost saving advantage of the land train system over the other two vehicle configurations increases with increasing fuel costs. A rigorous validation process, including a sensitivity analysis of results from FastTrack, revealed that the model performs predictably under a wide range of input conditions and could be a valuable tool for decision making in the sugar industry. However, further research is required to combine more economic and logistical aspects into FastTrack and to increase its usability. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.
9

Simulation modelling of sugarcane harvest-to-crush delays.

January 1998 (has links)
Long delays between harvesting and crushing of sugarcane lead to excessive deterioration in the quality of sugarcane. The aim of this project was to develop a computer based model of sugarcane harvesting and delivery systems that could be used to investigate methods of reducing harvest-to crush delays. A literature review was conducted and simulation modelling was chosen as the most appropriate modelling technique for the situation of sugarcane harvesting and delivery and the purposes of this project. The Arena modelling system was chosen as the simulation software with which to construct the model. A model was developed on the scale of a particular sugar mill and the area of farms supplying it with cane. The Sezela mill on the south coast of KwaZulu-Natal, South Africa was chosen as a case study on which to develop and test the model. The model integrated a harvesting and transport section which represented all the individual farms or combinations of farms in the area with a millyard section. After the model had been verified and validated, it was used to investigate the effect of a number of different scenarios of harvesting and delivery systems and schedules on harvest-to-crush delays in the Sezela mill area. The results of the experimental runs performed with the model indicated that the most significant decreases in harvest-to-crush delays could be brought about by matching harvesting, delivery and milling cycles as closely as possible. It was also evident that burn-to-cut delays where daily burning is not practised constitute a large proportion of overall harvest-to crush delays. The model proved to be useful in making comparisons between systems and in providing a holistic view of the problem of harvest-to-crush delays. Recommendations for future developments of the model include adding a mechanical harvesting component and making the model more easily applicable to other mill areas. / Thesis (M.Sc.Eng.)-University of Natal, 1998.
10

Improving the productivity and competitiveness of small-scale sugarcane contractors in KwaZulu-Natal.

Nothard, Brendon Wasley. January 2004 (has links)
The productivity of small-scale sugarcane contractors affects not only their own profitability and sustainability, but that of other stakeholders as well, such as the small-scale sugarcane farmers they contract to and the sugar mills these farmers supply in the form of improved services to growers and a steady flow of sugarcane to mills. This study firstly illustrates the organisational structures of the sugar industry. It then aims to identify constraints that inhibit the performance (such as timely haulage operations and cost effectiveness) of small-scale sugarcane contractors in the small-scale sugar industry of KwaZulu-Natal (KZN). To obtain this information, interviews were conducted with 124 randomly selected contractors from 11 mill group areas in KZN between September 2002 and July 2003. Case studies (concerning institutional issues such as organisational structures) of contractors, sub-committee members, and development officers were also conducted in eight mill group areas of KZN between September 2002 and February 2004. Sample statistics and case study results show that contractors face institutional constraints (work allocation limitations, lack of performance incentives and high transaction costs, such as negotiation costs, the risk of losing work and contract default risk), cash flow problems, poor physical infrastructure and a lack of labour. It is concluded that the promotion of a more competitive small-scale sugarcane contractor sector will alleviate many of the problems (such as work allocation limitations) faced by small-scale contractors, while providing incentives for the provision of higher quality and cheaper services to small-scale sugarcane growers. The study also examines the attributes of small-scale sugarcane contractors that affect their quality of service as perceived by small-scale sugarcane growers (SSGs) within current institutions. Information is drawn from the same sample survey, although ten observations from the Umfolozi area are excluded because they were not part of the sample drawn from population lists. Further interviews were conducted in the same time period with SSGs for information on contractor service quality (transport and general service timeliness, meeting of daily ratable delivery requirements, low downtimes, good staff management, and minimal disagreements on service terms). Results show that factors affecting a contractor's perceived service quality include gender, training, the quality of information used (industry focused information sources such as the South African Sugar Association Experiment Station (SASEX) and the Ingede magazine, or general sources such as the radio), and sugarcane tonnage transported (size of business). Being a male contractor and having a larger business positively influence service rating as perceived by SSGs. The importance of the quality of information used and increased training levels highlights the need for the continual provision of relevant information and training for sugarcane contractors by extension services (government, SASEX and milling companies). The study also identifies the need for further research on the issue of contractor machinery costs. In a competitive sector contractors would need to have adequate information on own costs in order to compare these with contract rates in the market. Further guidance by extension staff and other industry advisors (e.g. development officers) in the accessing of adequate finance may also be necessary. Government has a role in strategising the creation of land markets to promote efficient use of resources (land), while providing improved rural infrastructure (mainly district roads). Government also needs to ensure unbiased tribal court rulings, review the impacts of minimum wage legislation on contractors sourcing labour, and provide protection for those competing for work. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2004.

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