Browsing by Author "Bezuidenhout, Carel Nicolaas."

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A simulation study of cane transport system improvements in the Sezela Mill area.
(2009) Giles, R. C.; Bezuidenhout, Carel Nicolaas.
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.
An integrated sugarcane supply chain model : development and demonstration.
(2006) Stutterheim, Peter.; Bezuidenhout, Carel Nicolaas.; Lyne, Peter William Liversedge.
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.
An assessment of the feasibility of quality indicators for the postharvest deterioration of sugarcane (Saccharum officinarum L.)
(2014) Sibomana, Milindi Sylver.; Bezuidenhout, Carel Nicolaas.; Workneh, Tilahun Seyoum.; Sobratee, Nafisa.; Rutherford, Richard Stuart.
Sugarcane deterioration remains one of the most important supply chain efficiency leverage points in the South African sugar industry. Cane quality has been identified as an issue that has the potential to improve the overall efficiency of the sugarcane supply chain. A review comparing the postharvest quality management systems and measurements in the South African sugar and fresh produce industries was conducted. The difference in postharvest handling between the two industries was found to be an important factor dictating quality management. Advances in non-destructive quality measurement techniques and sanitation strategies were found in the fresh produce industries, which could be adopted by the South African sugar industry. An empirical study of standard sugar industry cane quality parameters was also performed. Sugarcane quality parameters measured at the Felixton mill were analysed, per ward, using quality control charts and non-parametric statistical approaches. A daily analysis of these parameters, as well as the Pol % Fibre ratio, using Shewhart quality control ( x ) charts revealed that, overall, Monday deliveries were of significantly lower quality (P<0.01). This is a quantitative indicator of logistics (or management) inefficiency over the weekend. Using the Mann-Whitney test, Pol % Fibre was used to generate a grower performance index, based on high levels of statistical significance (P<0.05), which may allow stakeholders to improve operations, through identifying the levels at which individual growers deliver significantly (P≤0.05) lower quality cane in the early part of the week. This study uncovered new and significant statistical trends within the sugar industry's quality database and demonstrates the potential of Pol % Fibre as an indicator of quality inferiority in the cane supply chain. To further investigate cane deterioration in this context, two burn/harvest-to-crush delay trials involving two sugarcane varieties (N12 and N31), which were exposed to ambient environmental conditions for a period of nine days after harvest were performed. On sampling dates, each variety was tested for quality parameters such as total bacterial counts, D-lactate production, and respiration. Standard sugar industry quality parameters and Pol % Fibre were also monitored. Parameters were measured in bottom, middle and top portions of the stalks to evaluate the effect of section on the parameter changes. Trial 1 was conducted on unburnt cane in October 2012 and Trial 2 on burnt cane, April-May 2013. Stalk portion significantly (P<0.001) affected the parameters, with the top and bottom portions showing higher bacterial proliferation, respiration rates and D-lactate production compared to the middle portion in Trial 1. Trial 2 showed no significant variability in stalk portion. In Trial 1, a significant (P<0.05) declining trend was noted for Brix % DM and Pol % Fibre in the top portion. The effect of higher respiration in the cut-ends in Trial 1 was noted in significantly reduced Pol % Fibre in these cut-ends. Environmental conditions were found to be the major factor influencing quality during the cane storage period. The study concludes, from both analysis of CTS data and the results of the BHTCD trials, that Pol % Fibre can be monitored at sugar mills as an additional parameter for signalling inferior quality and deterioration of cane consignments.
Characterisation of indigenous Zulu (Nguni) sheep for utilisation improvement and conservation.
(2010) Kunene, Nokuthula Winfred.; Nsahlai, Ignatius Verla.; Bezuidenhout, Carel Nicolaas.; Nesamvuni, A. E.
The Nguni sheep of Zululand, South Africa, are called the Zulu sheep. They are a source of food and cash for the rural farmers of KwaZulu-Natal. There is insufficient information available about the characteristics of this breed and accordingly the breed is classified as “insecure”. Documentation of characteristics of a breed is important for its utilisation, improvement or conservation. This study was undertaken to document (i) the utilization of the Zulu sheep, (ii) some morphological characteristics, (iii) establishing a cost effective body measurement recording means and (iv) the intra- and inter-population genetic variation of the breed using random amplified polymorphic DNA markers. A survey was conducted to investigate the socio-economic and cultural values of the farmers attached to livestock including the Zulu sheep. A total of 76 rural farmers were interviewed in the areas of the Mhlathuze district in northern KwaZulu-Natal. Constraints and the indigenous knowledge of the farmers on livestock production were also recorded. The results confirmed that the Zulu sheep in the rural areas are indeed used as a source of protein and cash when necessary. Farmers reported that the Zulu sheep are tolerant to ticks and able to withstand the hot and humid conditions of northern KwaZulu-Natal. Goats and cattle as well as the Zulu sheep are also used for payment of dues in the tribal courts. Even so, Zulu sheep are not used for any cultural purposes. The system of management is fairly extensive. Some farmers apply indigenous knowledge as part of management practices. For instance, they use indigenous plants as nutrient supplements and for increasing the reproduction rate of these animals. Lack of modern animal husbandry skills was declared by the farmers as one of the main challenges. A perception among the farmers was that the Government could assist in addressing this challenge. Three populations of Zulu sheep reared extensively in three localities were used for the morphometric and genetic studies. The areas were the community of KwaMthethwa (Enqutshini), University of Zululand (UNIZULU) and Makhathini Research Station. Makhathini and KwaMthethwa are 260 and 40 km, respectively, away from UNIZULU. The morphometric study was undertaken to determine the extent of phenotypic diversity between Zulu sheep populations using six morphological characteristics. Effects of some factors (location, age, sex and season) on some of these traits were estimated. Results showed that the size of the body measurements, wither height (WH), heart girth (HG), live weight (LW) and scrotal circumference (SC) were significantly different between the populations. Variation in these body measurements was influenced significantly by the location, season, the sex and the age of sheep. Mature ewes weighed up to 32 kg whereas the rams weighed up to 38 kg. The differences in LW, HG and WH between the seasons were small. The SC increased with the age of the ram up to 28 cm for mature rams. Other traits observed were the colour and the ear length of Zulu sheep. Ear size ranged from ear buds to the most common large ears (9 to 14 cm). The dominating colours observed were brown and a combination of brown and white. Live weight prediction equations were estimated employing HG, WH and SC data. The LW prediction equations showed that the regression of HG and WH produce the best estimate equations of LW; however the HG alone also showed reliable LW estimates. Scrotal circumference was more precise for estimating the LW of younger rams below 22 months of age (R2 = 0.64 – 0.78). Fifty-two Zulu sheep from the three locations were used to assess the genetic variation within the Zulu sheep breed. A total of 2744 RAPD bands were generated ranging from 0.2 to 2 kb; ~46% of these bands were polymorphic. The genetic diversity was the lowest (5.17%) within the UNIZULU population, 8.62% within the KwaMthethwa population and highest (11.04%) within the Makhathini population. The genetic diversity between all populations was estimated at 21.91 %. Phenotypic diversity was relatively similar for the UNIZULU and Makhathini populations (41.25% and 45.63%, respectively). The phenotypic diversity between the three populations was 48.26%. Genetic and phenotypic diversity was lower for Makhathini and UNIZULU populations than for the KwaMthethwa population. It was concluded that the Zulu sheep is a smaller sized breed compared to the other South African indigenous sheep breeds like the Dorper which has been reported to have some similar characteristics to the Nguni sheep. The results confirmed that the Zulu breed has the capacity to survive without dipping and supplements during the dry season. This adaptation is of value to the communities of KwaZulu-Natal. Such characteristics warrant conserving the breed to prevent genetic erosion. The phenotypic and genetic diversity between the three populations of Zulu sheep may indicate that there is an opportunity of genetic exploitation by selecting animals based on phenotypic as well as genetic characteristics. In order to promote the conservation and sustainable use of the Zulu sheep, it was recommended that an open nucleus breeding scheme from lower-tier flocks (of the farmers) for pure breeding to nucleus flocks (in Government ranches) could be appropriate. The scheme would also address the challenges of animal husbandry as well as contribute to the improvement of the livelihood of the farmers. Farmers could use a tape measure to estimate the LW of sheep when they cannot afford scales. The morphological characteristics and the genetic diversity data generated from this study could be combined into a single data base for this sheep breed. More extensive studies, using the same or some additional phenotypic characters such as reproductive performance, need to be done. Genetic characteristics of Zulu sheep using microsatellites and mitochondrial DNA should be done to complement the present study.
A comprehensive qualitative and quantitative assessment of harvesting and other sugarcane supply chain disruptions within the Eston Mill supply area.
(2014) Kadwa, Muhammad.; Bezuidenhout, Carel Nicolaas.; Ortmann, Gerald Friedel.
The Eston Mill, which was established in 1994, is the newest in the KwaZulu-Natal sugar belt. Like for most other mills, it can be argued that there are inefficiencies in the supply chain due to systemic issues, which reduce optimum performance. The literature study involved a review of the factors which cause inconsistencies in sugarcane supply chains and the strategies implemented for improvement. This research study involved five main aims. First, a novice qualitative diagnostic analysis of the Eston sugarcane system, to identify a range of systemic issues and one pertinent problem, involving pay-weekends and subsequent labour absenteeism, was isolated for further investigation. This was conducted through explorative interviews and network analysis approaches. Secondly, based on the information from the diagnostic analysis, a model that predicts and quantifies the factors which influence daily crush rate disruptions at Eston, was developed, validated and verified. Thirdly, the extent of the pay-weekend problem area was systematically estimated in terms of frequency, variability and predictability. Fourthly, the cost of cutter absenteeism was conservatively quantified, based on two factors, namely, sugar recovery and mill operational costs. Lastly, a case study was carried out, which involved the feasibility of a mechanical harvesting system, to mitigate the impacts of labour absenteeism. The model involved the calibration of parameters for mill maintenance and operational stops, rainfall events and days in the week when slow crush rates occurred. The model captures approximately 64% of the variation observed in daily crush rates. Subsequent to the development of the model, additional cane supply disruptions, caused by cutter absenteeism, were also investigated. It was statistically verified that a significantly detectable degree of labour absenteeism occurs immediately after pay-weekends. There has been a general increased trend in cutter absenteeism from about 2007 until 2010. An economic analysis estimated the costs associated with cutter absenteeism to be approximately R1.3 million per season, for the Eston region. The alternative harvesting system case-study solution, was found to be risky. However, acquiring second-hand equipment, which was available on the market, is estimated to make the solution more feasible. Based on a literature search, this research is considered to be the most comprehensive analyses of sugarcane supply consistency at mill-scale worldwide. The model developed can be utilized to critically evaluate different sugarcane milling areas and could potentially make significant contributions to commercial sugarcane operations. The effectiveness of the model is dependent on usage in other milling areas, as well as other industries. In addition, the specific labour absenteeism coefficients for each season can possibly be investigated using other industries as well.
The design and testing of soil pressure sensors for in-field agricultural and forestry traffic.
(2005) Eweg, Jonathan Lindsay.; Lyne, Peter William Liversedge.; Bezuidenhout, Carel Nicolaas.
River stage or flow rates are required for the design and evaluation of hydraulic structures. Most river reaches are ungauged and a methodology is needed to estimate the stages, or rates of flow, at specific locations in streams where no measurements are available. Flood routing techniques are utilised to estimate the stages, or rates of flow, in order to predict flood wave propagation along river reaches. Models can be developed for gauged catchments and their parameters related to physical characteristics such as slope, reach width, reach length so that the approach can be applied to ungauged catchments in the region. The objective of this study is to assess Muskingum-based methods for flow routing ill ungauged river reaches, both with and without lateral inflows. Using observed data, the model parameters were calibrated to assess performance of the Muskingum flood routing procedures and the Muskingum-Cunge method was then assessed using catchment derived parameters for use in ungauged river reaches. The Muskingum parameters were derived from empirically estimated variables and variables estimated from assumed river cross-sections within the selected river reaches used. Three sub-catchments in the Thukela catchment in KwaZulu-Natal, South Africa were selected for analyses, with river lengths of 4, 21 and 54 km. The slopes of the river reaches and reach lengths were derived from a digital elevation model. Manning roughness coefficients were estimated from field observations. Flow variables such as velocity, hydraulic radius, wetted perimeters, flow depth and top flow width were determined from empirical equations and cross-sections of the selected rivers. Lateral inflows to long river reaches were estimated from the Saint-Venant equation. Observed events were extracted for each sub-catchment to assess the Muskingum-Cunge parameter estimation method and Three-parameter Muskingum method. The extracted events were further analysed using empirically estimated flow variables. The performances of the methods were evaluated by comparing both graphically and statistically the simulated and observed hydrographs. Sensitivity analyses were undertaken using three selected events and a 50% variation in selected input variables was used to identify sensitive variablesThe performance of the calibrated Muskingum-Cunge flood routing method using observed hydrographs displayed acceptable results. Therefore, the Muskingum-Cunge flood routing method was applied in ungauged catchments, with variables estimated empirically. The results obtained shows that the computed outflow hydrographs generated using the Muskingum-Cunge method, with the empirically estimated variables and variables estimated from cross-sections of the selected rivers resulted in reasonably accurate computed outflow hydrographs with respect to peak discharge, timing of peak flow and volume. From this study, it is concluded that the Muskingum-Cunge method can be applied to route floods in ungauged catchments in the Thukela catchment and it is postulated that the method can be used to route floods in other ungauged rivers in South Africa.
Developing a diagnostic heuristic for integrated sugarcane supply and processing systems.
(2019) Shongwe, Mduduzi Innocent.; Bezuidenhout, Carel Nicolaas.; Bodhanya, Shamim Ahmed.
Innovation is a valuable asset that gives supply chains a competitive edge. Moreover, the adoption of innovative research recommendations in agricultural value chains and integrated sugarcane supply and processing systems (ISSPS) in particular has been relatively slow when compared with other industries such as electronics and automotive. The slow adoption is attributed to the complex, multidimensional nature of ISSPS and the perceived lack of a holistic approach when dealing with certain issues. Most of the interventions into ISSPS often view the system as characterised by tame problems hence, the widespread application of traditional operations research approaches. Integrated sugarcane supply and processing systems are, nonetheless, also characterised by wicked problems. Interventions into such contexts should therefore, embrace tame and/or wicked issues. Systemic approaches are important and have in the past identified several system-scale opportunities within ISSPS. Such interventions are multidisciplinary and employ a range of methodologies spanning across paradigms. The large number of methodologies available, however, makes choosing the right method or a combination thereof difficult. In this context, a novel overarching diagnostic heuristic for ISSPS was developed in this research. The heuristic will be used todiagnose relatively small, but pertinent ISSPS constraints and opportunities. The heuristic includes a causal model that determines and ranks linkages between the many domains that govern integrated agricultural supply and processing systems (IASPS) viz. biophysical, collaboration, culture, economics, environment, future strategy, information sharing, political forces, and structures. Furthermore, a diagnostic toolkit based on the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) was developed. The toolkit comprises a diagnostic criteria and a suite of systemic tools. The toolkit, in addition, determines thesuitability of each tool to diagnose any of the IASPS domains. Overall, the diagnostic criteria include accessibility, interactiveness, transparency, iterativeness, feedback, cause-and-effect logic, and time delays. The tools considered for the toolkit were current reality trees, fuzzy cognitive maps (FCMs), network analysis approaches, rich pictures (RP), stock and flow diagrams, cause and effect diagrams (CEDs), and causal loop diagrams (CLDs). Results from the causal model indicate that collaboration, structure and information sharing had a high direct leverage over the other domains as these were associated with a larger number of linkages. Collaboration and structure further provided dynamic leverage as these were also part of feedback loops. Political forces and the culture domain in contrast, provided lowleverage as these domains were only directly linked to collaboration. It was further revealed that each tool provides a different facet to complexity hence, the need for methodological pluralism. All the tools except RP could be applied, to a certain extent, across both appreciation and analysis criteria. Rich pictures do not have causal analysis capabilities viz. cause-and-effect logic, time delays and feedback. Stock and flow diagrams and CLDs conversely, met all criteria. All the diagnostic tools in the toolkit could be used across all the system domains except for FCMs. Fuzzy cognitive maps are explicitly subjective and their contribution lies outside the objective world. Caution should therefore be practiced when FCMs areapplied within the biophysical domain. The heuristic is only an aid to decision making. The decision to select a tool or a combination thereof remains with the user(s). Even though the heuristic was demonstrated at Mhlume sugarcane milling area, it is recommended that other areas be considered for future research. The heuristic itself should continuously be updated with criteria, tools and other domain dimensions.
The development and evaluation of a performance-based standards approach for regulating the use of heavy vehicles in South Africa.
(2013) Nordengen, Paul Anthony.; Lyne, Peter William Liversedge.; Bezuidenhout, Carel Nicolaas.
The regulation of the use of vehicles on the road network is aimed at ensuring acceptable safety and recovery of road maintenance costs, as well as minimising congestion, road wear, excessive noise and air pollution. The traditional approach of regulating heavy vehicles is prescriptive, i.e. enforcing regulations that primarily limit the mass and dimensions of these vehicles. This approach is generally favoured because such regulations are easy to understand and enforce. However, an underlying disadvantage is that the prescriptive approach does not always adequately safeguard the dynamic performance of heavy vehicles while travelling on the road. Principle-based and performance-based standards are primarily aimed at specifying desired outcomes, rather than how these outcomes should be achieved. Under a performance-based standards (PBS) approach, performance measures (such as low-speed swept path, rearward amplification, load transfer ratio and high-speed offtracking) are utilised to specify the performance required from vehicles. Although more complex to regulate, a PBS approach has a number of potential benefits such as: (a) improved vehicle safety, (b) improved productivity, (c) reduced infrastructure wear and emissions, (d) a more optimal use of the existing road network, and (e) the encouragement of innovation in vehicle design. The aim of this research was to apply, refine and demonstrate an alternative approach to the design and operation of heavy vehicles in South Africa with improved outcomes in terms of road transport productivity, vehicle safety performance, emissions, congestion and preservation of road infrastructure. The research included the development and implementation of a PBS demonstration project in South Africa and the monitoring and evaluation of PBS demonstration vehicles operating in the forestry industry in the provinces of KwaZulu-Natal and Mpumalanga. Evaluation focused on improvements in productivity (fuel efficiency and trip reduction) and load control with reference to initial results regarding road wear and safety performance. Results show a significant improvement in payload control and fuel efficiency of the PBS vehicles compared with the baseline vehicles. This also resulted in a reduction in CO2 emissions per ton.km. Road wear assessments of PBS and baseline vehicles showed that in some cases a reduction in road wear of up to 200% per ton of payload can be achieved through the use of PBS vehicles. Safety assessment results of four PBS vehicle designs showed various shortcomings of prescriptive baseline vehicles in terms of the performance standards.
Development and evaluation of model-based operational yield forecasts in the South African sugar industry.
(2005) Bezuidenhout, Carel Nicolaas.; Schulze, Roland Edgar.
South Africa is the largest producer of sugar in Africa and one of the ten largest sugarcane producers in the world. Sugarcane in South Africa is grown under a wide range of agro-climatic conditions. Climate has been identified as the single most important factor influencing sugarcane production in South Africa. Traditionally, sugarcane mill committees have issued forecasts of anticipated production for a region. However, owing to several limitations of such committee forecasts, more advanced technologies have had to be considered. The aim of this study has been to develop, evaluate and implement a pertinent and technologically advanced operational sugarcane yield forecasting system for South Africa. Specific objectives have included literature and technology reviews, surveys of stakeholder requirements, the development and evaluation of a forecasting system and the assessment of information transfer and user adoption. A crop yield model-based system has been developed to simulate representative crops for derived Homogeneous Climate Zones (HCZ). The system has integrated climate data and crop management, soil, irrigation and seasonal rainfall outlook information. Simulations of yields were aggregated from HCZs to mill supply area and industry scales and were compared with actual production. The value of climate information (including climate station networks) and seasonal rainfall outlook information were quantified independently. It was concluded that the system was capable of forecasting yields with acceptable accuracy over a wide range of agro-climatic conditions in South Africa. At an industry scale, the system captured up to 58% of the climatically driven variability in mean annual sugarcane yields. Forecast accuracies differed widely between different mill supply areas, and several factors were identified that may explain some inconsistencies. Seasonal rainfall outlook information generally enhanced forecasts of sugarcane production. Rainfall outlooks issued during the summer months seemed more valuable than those issued in early spring. Operationally, model-based forecasts can be expected to be valuable prior to the commencement of the milling season in April. Current limitations of forecasts include system calibration, the expression of production relative to that of the previous season and the omission of incorporating near real-time production and climate information. Several refinements to the forecast system are proposed and a strong collaborative approach between modellers, climatologists, mill committees and other decision makers is encouraged.
Development of a spatial sugarcane transport infrastructure-planning model.
(2008) Harris, Alasdair John.; Bezuidenhout, Carel Nicolaas.; La Grange, Louis Francois.
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.
Development of network theory approaches to analyse cause and effect relationships in complex integrated sugarcane supply and processing systems.
(2013) Sanjika, Thawani M.; Lyne, Peter William Liversedge.; Bezuidenhout, Carel Nicolaas.; Bodhanya, Shamim Ahmed.
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.
Evaluating the effects of pre-packaging, packaging and varying storage environment treatments on the quality of avocados (Persea americana mill.)
(2013) Kassim, Alaika.; Workneh, Tilahun Seyoum.; Bezuidenhout, Carel Nicolaas.
Avocados are characterized as climacteric fruit and are vulnerable to rapid physiological deterioration. Maintaining avocado fruit quality requires proper integrated postharvest technologies. Thus, the primary aim of this study was to evaluate the effects of combined postharvest treatments and storage conditions on the physical, chemical and subjective sensory quality parameters of the ‘Hass’ avocado. The study was divided into two experiments. Experiment I investigated the combined effects of postharvest handling treatments and fixed temperature (5°C or 10°C) and relative humidity (85% or 90%) on the quality of avocados for a storage period of 12 days. Experiment II focused on the combined effects of postharvest treatments and temperature-varying storage conditions (5.5°C ± 0.01°C for two days, 5°C ± 0.01°C for six days and 4.5°C ± 0.01°C for 20 days and 95% relative humidity), by simulating a realistic avocado cold chain for 28 days. A Randomised Complete Block Design with pre-packaging (hot water and Avoshine® wax coating), packaging (low density polyethylene (LDPE) and corn starch biodegradable films) and storage conditions (as mentioned above and ambient) with three replications was used in both experiments. The quality parameters that were evaluated included physiological weight loss (PWL), respiration rate, marketability, skin colour, firmness, puree colour, puree viscosity, moisture content (MC), dry matter (DM), pH, total soluble solids (TSS) and total titratable acidity (TTA). The storage conditions and the storage period significantly (P≤0.001) affected the quality parameters that were evaluated in both experiments. Low temperature storage offered the greatest benefit in maintaining high marketability, reduced PWL and delayed the peak in respiration, compared to ambient conditions in both experiments. Control samples exhibited increased rates of ripening, which was evident in increased PWL, reduced firmness, darkened skin colour, rapid decline in pH as well as increased TTA and TSS. The Avoshine® coating, combined with LDPE packaging, was favourable in maintaining a lower PWL, higher marketability, higher MC and lower DM indicative of delayed ripening. Hot water treatment promoted the darkening of the skin, decreased pulp firmness and lowered the marketability. The findings show that cold storage, combined with Avoshine® and LDPE packaging improved the shelf life by two weeks and preserving the quality of avocados during short and extended storage durations, compared to control samples.
The evaluation of pressure distribution and bulk density models for infield agriculture and forestry traffic.
(2006) Marx, Barend Jan.; Bezuidenhout, Carel Nicolaas.; Lyne, Peter William Liversedge.
There is evidence that soil compaction, through the use of mechanised equipment, causes detrimental effects to soil quality and reduces long-term productivity of soils. For economic reasons, farmers need to purchase larger, heavier machinery in order to cultivate larger areas under crops, resulting in larger forces on the soil. The severity of soil compaction is governed by various soil and vehicle properties and normally causes an increase in the soil's bulk density and a decrease in the air filled porosity. These changes in soil properties have negative effects on crop production and environmental sustainability. The aim of this study was to investigate and develop a model based decision support system for soil compaction management and research. Soil compaction occurs during the transfer of stresses from the tyre interface into the soil. Numerically, it has been modelled using both mechanistic and empirical models, which attempt to simulate the stress propagation and also sometimes the consequent damage to the soil. The SOCOMO soil compaction model is described and this model computes the stress at a point in the soil for any given horizontal and vertical stress distribution at the soil / tyre interface. It has been successfully used in the Netherlands and in Sweden to map the impact on the soil. The SOCOMO model was tested and verified at a forestry site in Richmond, KwaZulu- Natal. Relationships to determine bulk density were also tested and verified. The SOCOMO model performs satisfactory (RMSE = 47.9 kPa), although it tends to overestimate the pressures within the soil. This could be as a result of the high organic carbon content in the particular soil. Models predicting bulk density also performed satisfactory (RMSE = 69.9 kg.m" ), but resultant densities in the soil are generally underestimated. Future research is needed to find better relationships to estimate changes in dry bulk density and to test the model on a wider range of soils. If the model performs satisfactory it could provide a useful tool to determine the impact of soil compaction on crop yield.
An investigation into sugarcane vehicle loading with respect to influences on overall transport efficiency.
(2011) Moodley, Samantha.; Bezuidenhout, Carel Nicolaas.
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.
Issues pertaining to cane supply reliability and stockpiling at the Umfolozi sugar mill - model development and application.
(2011) Boote, Gordon L. N.; Bezuidenhout, Carel Nicolaas.; Lyne, Peter William Liversedge.
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.
Modelling sugarcane quality in the context of mill scale supply chain logistics.
(2014) Jenkins, Edwin Peter Garland.; Bezuidenhout, Carel Nicolaas.; Ortmann, Gerald Friedel.
The length of milling season (LOMS) refers to the length and timing of sugarcane crushing operations at a sugar mill. LOMS is central to the competitiveness and profitability of any sugar mill supply area (MSA). Conflicting interests between supply chain stakeholders can make adjusting the LOMS difficult. The LOMS should take into account weather conditions, cane quality, milling capacity, supply chain capabilities and other interrelated issues, such as agronomics. Previous LOMS models in South Africa were developed over a decade ago and there was scope to improve the calculation of risks by using a stochastic modelling approach. Recently, a stochastic model named LOMZI was developed to evaluate stockpiling options at Umfolozi. In this study, LOMZI was adapted and expanded to allow the LOMS for any MSA in South Africa to be investigated. However, mill area specific applications of the updated model fell outside the scope of this study. As it currently stands, LOMZI simulates a sugarcane supply chain from the point where sugarcane is cut, up to delivery at the mill. During the process of adapting LOMZI, the simulation of sugarcane quality was identified as an important area for improvement in the model and this became the focus of the study. A predictive MSA scale cane quality model was developed, based on recent weather conditions and a mechanistic understanding of sugarcane quality. The quality model was developed to simulate the daily average brix %, pol % and fibre % of sugarcane delivered to the mill. The preceding 11 weeks’ rainfall and temperature values were used to predict cane quality. A total of 98 mill-specific coefficients were calibrated from historic milling data and, for model demonstration purposes, the quality model was applied at two mills, namely Sezela and Umfolozi. Independent verifications yielded R2 values between 0.56 and 0.74. A useful method to estimate the average burn/cut to crush delay for a MSA was also identified. The quality model has been successfully integrated with LOMZI. Future work is envisaged to expand LOMZI and to model the operations of sugar mills and the RV cane payment system.
Sex rather than wastewater associated stresses determines intestinal bacterial communities in the insectivorous bat, neoromicia nana.
(2017) Mehl, Calvin Carl.; Vosloo, Dalene.; Schoeman, Marthinus Cornelius.; Bezuidenhout, Carel Nicolaas.; Preiser, Wolfgang.
Wastewater treatment works (WWTWs) receive influent from domestic, agricultural and industrial sources, producing a cocktail of toxicants at these sites. WWTWs are unable to remove all the toxicants or bacterial and viral pathogens in the wastewater before it is released into surrounding ecosystems. Large amounts of nutrients in the wastewater supports abundant populations of chironomid midges (Diptera), that transfer these toxicants to their predators, such as Neoromicia nana (Vespertilionidae), resulting in numerous biochemical and metabolic effects. However, little is known if foraging at WWTWs affects the intestinal bacteria of bats. This study compared intestinal bacteria communities that play essential roles in nutrient absorption and immunity in their hosts between N. nana populations at WWTWs and reference sites. I hypothesised that bacterial communities of N. nana should differ between individuals foraging at WWTWs and reference sites. Next generation sequencing was used to identify intestinal bacteria of bats at two reference sites (Buffelsdrift and Inkunzi) and two WWTWs (Verulam and Umbilo). Differences in intestinal bacterial loads (at each taxonomic level) and host attributes (sex, body condition, locality) of individuals were quantified using the Gower distance measure. Hierarchical cluster analysis was used to identify the factors that determine the similarity between individuals. As predicted, bats at WWTW sites showed greater intestinal bacteria diversity than those at reference sites. This is likely due to exposure to the high diversity of bacteria within wastewater. Further, differences in certain bacterial taxa, such as the family Chitinophagaceae, may be due to differences in diet between WWTWs and reference site bats. Statistical analyses revealed that sex, and site to a lesser degree, were the best predictors of similarity in intestinal bacteria communities among N. nana bats. Because bacterial diversity did not correlate with body condition, sex-specific factors (such as sex hormones) may be the greatest drivers of these differences. Further, site specific factors such as toxicant and ectoparasite exposure likely had some influence on the difference observed between reference and WWTWs bats. Dysbiosis of intestinal bacterium communities, because of wastewater exposure, may have significant sex-biased impacts on host metabolism and immune functioning.
A study on reducing primary transport costs in the South African timber industry.
(2005) Lusso, Cary D.; Lyne, Peter William Liversedge.; Bezuidenhout, Carel Nicolaas.
Harvesting and transport accounts for up to 70% of the total production cost of roundwood in South Africa. This invokes an interest to improve harvesting systems through the introduction of improved equipment, road networks and more refined operating techniques. A literature review was conducted which investigated the various harvesting systems and equipment with a focus on ground based extraction, as it accounts for 96% of the timber being extracted annually in South Africa. A review of forest roads in South Africa was also conducted and it was concluded that at present there has been little focus on the upgrading and maintenance of forest road networks. It was concluded that the most significant reduction in transport costs would be achieved by reducing the distances travelled by expensive extended pnmary transport (R5.83 t-1.km-1) and by allowing less expensive secondary terminal transport (R0.4 t-1.km-1) to move further into the plantations. This could only be achieved by investing large amounts of capital into the upgrading of forest roads to a standard suitable to service secondary transport vehicles. A model was developed which was able to determine the tonnage of timber needed to flow over a particular road that will warrant the upgrading cost. The model was applied to two study areas, the first study yielded no results due to the already dense network of B- class roads, possibly excessive. The second study area identified three possible road upgrades to improve the existing transport system. A full costing of the existing and modified transport system was completed and a significant cost saving was shown, not accounting for the road upgrading cost. Capital budgets were used to account for more complex parameters, such as tax and discount rates, previously excluded from the simple model. These were used to determine the economic viability of the upgrades and to evaluate the suitability of the model. The model proved to be successful and confirmed that forest roads can be optimised accompanied by significant cost savings. The model is generic and simple allowing for easy application to a variety of situations and is also flexible to modifications.
Systemic approaches to improvement in sugarcane production and supply : Umfolozi and Felixton Mill areas.
(2013) Hildbrand, Sandra.; Bodhanya, Shamim Ahmed.; Bezuidenhout, Carel Nicolaas.
Within the South African sugar industry, several possibilities for performance improvement exist. Present inefficiencies arise largely from the complexity of integrated sugarcane production and supply systems. Research has mainly concentrated on technical, hard aspects, such as mill and transport efficiency and sugarcane quality in an attempt to optimise these systems by optimising their parts. Soft issues, like communication, trust, and values have been neglected. This study considers sugarcane production and supply systems more holistically and places a particular focus on soft and leadership issues. Two systems methodologies, Soft Systems Methodology (SSM) and the Viable System Model (VSM) were applied to investigate the complexity of two large sugarcane production and supply systems in KwaZulu-Natal, South Africa in the Felixton and Umfolozi milling areas. These methodologies were combined with a qualitative approach which facilitated a thorough exploration of crucial soft and leadership issues. The outcome of the empirical work showed that a core issue challenging both milling areas and the entire sugar industry is the presence of fragmentation. Factors that contribute to fragmentation and suggestions for its handling are presented. SSM and VSM fostered an in-depth understanding of the studied system, yet their ability to suggest improvements was not confirmed. Since it is argued that this was largely impeded by the conditions of the study, the thesis overall supports the suitability of both methodologies in the sugar industry context and encourages their further use. The thesis emphasises the necessity to adopt a holistic approach and pay attention to soft issues when dealing with sugarcane production and supply systems. By implication, systemic approaches in general seem significant in this context. Neither SSM nor VSM were previously utilised to investigate a sugarcane production and supply system, hence this thesis makes a meaningful contribution to the existing body of SSM and VSM knowledge. It highlights the strengths and shortfalls of these systems methodologies in the applied context and presents derived methodological lessons. These lessons broaden the knowledge of employing SSM and VSM and support their application in practice.
Using system dynamics to explore the poor uptake of irrigation scheduling technologies in a commercial sugarcane community in South Africa.
(2016) Jumman, Ashiel.; Bezuidenhout, Carel Nicolaas.
Abstract available in PFD file.