Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2005. / The objective of the thesis is to improve the performance prediction of axial compressors, using a streamline throughflow method (STFM) code by modelling the hub and casing wall boundary layers, and additional flow mechanisms that occur within a blade row passage. Blade row total pressure loss and deviation correlations are reviewed. The effect of Mach number and the blade tip clearance gap are also reviewed as additional loss sources. An entrainment integral method is introduced to model the hub and casing wall boundary layers. Various 1-dimensional test cases are performed before implementing the integral boundary layer method into the STFM. The boundary layers represent an area blockage throughout the compressor, similar to a displacement thickness, but affects two velocity components. This effectively reduces the compressor flow area by altering the hub and casing radial positions at all stations. The results from the final STFM code with the integral boundary layer model, Mach number model and tip clearance model is compared against high pressure ratio compressor test cases. The blockage results, individual blade row and overall performance results are compared with published data. The deviation angle curve fits developed by Roos and Aungier are compared. There is good agreement for all parameters, except for the slope of deviation angle with incidence angle for low solidity. For the three compressors modelled, there is good agreement between the blockage prediction obtained and the blockage prediction of Aungier. The NACA 5-stage transonic compressor overall performance shows good agreement at all speeds, except for 90% of design speed. The NACA 10-stage subsonic compressor shows good agreement for low and medium speeds, but needs improvement at 90% and 100% of design speeds. The NACA 8-stage transonic compressor results compared well only at low speeds.

Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2006. / The main objective of this thesis was to design a hydrofoil system without a trim and ride height control system and investigate the change in resistance of a representative hull across a typical speed range as a result of the addition of the hydrofoil system, while retaining adequate stability. The secondary objectives were as follows: Find a representative hull of sailing catamarans produced in South Africa, and to establish an appropriate speed range for that hull across which it is to be tested. Test and explain the drag characteristics of this hull. Find a suitable configuration of lifting foils for this hull that would not require any form of trim or ride height control to maintain stability throughout the speed range. Test and compare the resistance characteristics with and without the assistance of lifting foils. Test and explain the effects of leeway and heel on the total hydrodynamic resistance both with and without lifting foils. A representative hull (RH1), based on a statistical analysis of sailing catamarans produced in South Africa and an existing hull design of suitable size, was designed. A speed range was then established (0 – 25 knots) based on the statistics of the original (existing) design. A scaled model (of RH1) of practical and suitable dimensions was designed and manufactured, and its characteristics determined through towing tank testing. A hydrofoil system was then designed and during testing, was adjusted until a stable configuration was found. This resulted in a canard type configuration, with the front foil at the bow and the main foil between the daggerboards. Although a stable configuration was achieved, it was noted that any significant perturbation in the trim of the boat would result in instability and some form of trim control is recommended. The main objective was achieved. The experimental results concluded that a canard configuration was found to be stable for the RH1 (foil positioning already mentioned) and the addition of the hydrofoils provided a significant improvement only above a displacement Froude number of 2, which for our full scale prototype, is equivalent to approximately 14.2 knots. This is in agreement with the results of several other research projects that investigated hydrofoil supported catamarans with semi‐displacement type demi‐hulls. Below displacement Froude number of 2, a significant increase in total hydrodynamic resistance was observed. Since the speed of sailing craft is dependent on wind speed, there will often be conditions of relatively low boat speed (below displacement Froude number of 2). So it was recommended that a prototype design would have a retractable hydrofoil system which could be engaged in suitable conditions (sufficient boat speed). The effects of leeway and heel on the total hydrodynamic resistance were determined experimentally, but it was found that these trends were affected by the resulting changes in wave interference resistance. Since wave interference depended strongly on the hull shape, it was therefore concluded that no universal trends can be determined regarding the effects of heel and leeway on the total hydrodynamic resistance. These effects were determined for RH1 and it was shown that these effects are drastically altered by the addition of the lifting foils.

Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2000. / A solar chimney power plant consists of a central chimney that is surrounded by a transparent canopy located a few meters above ground level. The ground beneath this canopy or collector as it is known is heated by the solar radiation that is effectively trapped by the collector. This in turn heats the air in the collector, which flows radially inwards towards the chimney. This movement is driven by the difference between the hydrostatic pressure of the air inside- and outside the solar chimney system. The energy is extracted from the air by a turbine driven generator situated at the base of the chimney. The performance of such a solar chimney power plant is evaluated in this study making use of a detailed mathematical model. In this model the relevant discretised energy and draught equations are deduced and solved to determine the performance of a specific plant referred to as the "reference plant". This plant is to be located at a site near Sishen in the Northern Cape in South Africa where meteorological data is available. The performance characteristics of this plant are presented using values from the 21 st of December as an example. These characteristics include the instantaneous and integrated power output, as well as the absorption of the solar radiation of each of the parts of the collector. The air temperatures throughout the plant and the convective heat transfer coefficients in the collector in the region of developing and fully developed flow are presented. The pressure of the air throughout the system is presented as well as the pressure drop over the turbine. Temperature distributions in the ground below the collector are also presented and discussed.

Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2005. / This work is concerned with the design and hydrodynamic aspects of a hydrofoil-assisted trimaran. A design and configuration of a trimaran is evaluated and the performance of a hydrofoil-assisted trimaran is effectively compared to the performance of a hydrofoil-assisted catamaran with similar overall displacement and same speed. The performance of the trimaran with different outrigger clearances are also evaluated and compared. The hydrodynamic aspects focuses mainly on the performance and to a lesser extend on the sea-keeping and stability of a hydrofoil-assisted trimaran. The results were determined by means of experimental testing, theoretical analysis and numerical analysis. The project was initiated as a result of the success of the hydrofoil-assisted catamarans and due to the fact that there does not exist a hydrofoil-assisted trimaran (to the author’s knowledge) where the main focus of the foils is to significantly reduce the resistance. A brief history, recent developments and associated advantages regarding trimarans are discussed. A complete theoretical model is presented to evaluate the lift and drag of the hydrofoils, as well as, the resistance of the trimaran. The data so obtained is then used to compare the reliability and feasibility of the numerical and experimental predicted values. The design of the trimaran and hydrofoil system is explained, together with the problems associated with the final design of the trimaran. The design of a trimaran is much more complicated than a catamaran due to more design variables being associated with trimarans. The selection of the trimaran configuration is done in a logical manner considering stability and hydrodynamics. However, the hydrofoil-assisted trimaran is closely adapted to the main dimensions of the comparable hydrofoil-assisted catamaran. An in-depth discussion of the testing technique used and the problems that are associated with towing tank testing will facilitate similar tests in the future. The scaling method of Froude was modified to account for the different sized hulls. The numerical methods are explained, with emphasis on accuracy, limitations, feasibility and the time required to complete a calculation. The results are presented in an order suggested by the experimental and numerical work carried out. The resistance, trim and rise/sinkage results are presented with speed for both the trimaran and catamaran with and without the addition of foils. The addition of the foils supplies results based on the amount of lift the foils carry and therefore can easily clarify the significant resistance advantage the foils offer the trimaran and the catamaran evaluated in this project. The final design and results of the evaluated trimaran are discussed. It is concluded that the catamaran with similar displacement and speed is still superior to the trimaran, with and without foils in both cases. The addition of foils to the trimaran does decrease the resistance significantly. The conclusions regarding these results are presented, together with recommendations for future work.

Thesis (MScIng)--University of Stellenbosch, 2008. / ENGLISH ABSTRACT: The focus of this project was the application of a passive device in the form of a loop thermosyphon as a reactor cavity cooling system (RCCS) for a Pebble Bed Modular Reactor. An extensive literature review showed that loop thermosyphons have been widely researched, both theoretically and experimentally. In the review attention has specifically been given to matters such as safety, instability, control and mathematical modelling. One of the objectives of the project was to build one of the axially symmetric sections of Dobson’s (2006) proposed full scale RCCS using a scaled down version consisting of a single loop heated by a section of the reactor pressure vessel and cooled by a tank of water. The second objective was to derive a theoretical model that could be used in a computer code to simulate the experiment. The theory and experiment would then be compared in order to verify the code. The mathematical model created used the following three major assumptions: quasistatic flow, incompressible liquid and vapour and one dimensionality. The conservation equations in the form of a set of difference equations with the appropriate closure equations were then solved explicitly. It was found that the theoretical results were heavily influenced by the surface optical properties as well as the heat transfer coefficients. The emissivity influenced the transition point from single to two-phase flow as well as the condenser outlet temperature. The single phase heat transfer coefficients influenced the condenser outlet temperature significantly while it was found that for two phase flow the combination of the available boiling and condensation heat transfer coefficients had only minor effects on the end results. A stainless steel and aluminium thermosyphon loop was built using water as the working fluid. A stainless steel heater plate provided the heat input while a 200 L water tank was the heat sink. Temperature and flow rate measurements were recorded as a function of time with various heating/cooling transients from start-up to steady state for three operating modes. The three operating modes were single phase, two-phase and heat pipe mode. It was found that the theoretical temperatures correspond reasonably well with the experimental temperatures. The time predicted by the theoretical model to reach the operating temperature was however somewhat longer than for the experimental. This is to be expected when considering that there is some uncertainty pertaining to the heat transfer coefficients as well as surface emissive properties. The correspondence of the theoretical and experimental fin temperatures was poor due to significant thermal stratification of the air separating the heater plate and fins. Several shortcomings in the theoretical model as well as the experimental setup were identified and discussed. The conclusion was reached that this exploratory study showed that the loop thermosyphon is a viable option for the RCCS and that the mathematical model is a viable theoretical simulation tool. Several recommendations were made for further study to address and overcome the shortcomings identified in the theoretical and experimental models in order to prove this conclusion. Amongst these is the determination of better material surface properties and heat transfer coefficients and improved mass flow rate measurement. Investigating scaling issues, natural convection outside the loop and updating of the computer program is also recommended. / AFRIKAANSE OPSOMMING: Die fokus van hierdie projek was die toepassing van passiewe apparatuur, in die vorm van ‘n geslote lus termoheuwel, as ‘n reaktor kamer verkoellings stelsel vir die korrel bed modulêre reaktor. Die literatuur studie wys dat hierdie tegnologie reeds breedvoerig ondersoek is teoreties sowel as eksperimenteel. In die literatuur oorsig word aandag spesifiek gegee aan veiligheid, onstabiliteit, beheer en modelleering. Een van die doelwitte van die projek was om ‘n klein skaalse model te bou van een van die aksiaal simmetriese seksies van Dobson (2006) se voorgestelde volskaalse reaktor kamer verkoellings stelsel. Die model bestaan uit n enkele lus verhit deur ‘n seksie van die reaktor drukvat en verkoel deur ‘n tenk vol water. Die tweede doelwit was die afleiding van ‘n teoretiese model wat in ‘n rekenaar program gebruik kan word om die eksperiment te simuleer. Die teoretiese en eksperimentele data kan dan vergelyk word om die geldigheid van die program te toets. Die volgende aanames is gemaak tydens die afleiding van die wiskundige model: kwasi-statiese vloei, onsamedrukbare vloeistof en gas en een dimensionalitiet. Die behouds wette is in die vorm van ‘n stel differensie vergelykings met die toepasbare sluitings vergelykings eksplisiet opgelos. Dit is bevind dat die teoretiese resultate swaar beinvloed is deur die materiaal oppervlak eienskappe sowel as die warmteoordrag koëffisiënte. Die emisiviteit beinvloed die oorgangs punt van enkel na twee fase vloei sowel as die kondenser uitlaat temperatuur. Die enkel fase warmteoordrag koëffisiënt het n beduidende invloed op die kondenser uitlaat temperatuur terwyl dit voorkom asof die spesifieke kombinasie van die koking en kondensasie warmteoordrag koëffisiënte minimale invloed op die resultate het in die twee fase gebied. Vlekvrye staal en aluminium is gebruik om die lus te bou met water as die verkoelings middel. Warmte is toegevoeg tot die stelsel deur ’n vlekvrye staal verhittings plaat terwyl ‘n 200 L water tenk die warmte onttrek het. Temperatuur en massa vloei tempo is aangeteken as ‘n funksie van tyd vir verskeie verhitting/verkoellings oorgangs gedragte vanaf begin tot bestendige toestand vir drie bedryfs modusse. Die drie bedryfs modusse was enkel fase, twee fase en hitte pyp modus. Dit is bevind dat die teoretiese temperature redelik goed ooreengekom het met die eksperimentele waardes. Die tyd wat dit neem om by die bedryfs temperatuur te kom soos voorspel deur die teorie is egter langer as wat in die eksperiment gevind is. Dit is te verstane wanneer die onsekerheid in die warmteoordrag koëffisiënte en materiaal oppervlak eienskappe in ag geneem word. Die fin temperature het ‘n swakker ooreenkoms getoon as gevolg van beduidende termiese stratifikasie van die lug tussen die fin en verhittings plaat. Verskeie tekortkominge in die teoretiese model en eksperimentele opstelling is geïdentifiseer en bespreek. Die gevolgtrekking is gemaak dat die ondersoek bewys dat geslote lus termoheuwels ‘n lewensvatbare opsie is vir ‘n reaktor kamer verkoellings stelsel en dat die wiskundige model lewensvatbaar is vir teoretiese simulasie. Verskeie aanbevelings word egter gemaak om die tekortkominge in die teoretiese en eksperimentele modelle aan te spreek om so doende die gevolgtrekking te staaf. Dit word aanbeveel dat beter waardes vir die materiaal oppervlak eienskappe en warmteoordrag koëffisiënte gevind word en verbeterde massa vloei meetings gedoen word. Dit word verder aanbeveel om skaleering asook natuurlike konveksie buite die lus te ondersoek en om die rekenaar program by te werk.

Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2006. / The quest for higher efficiency of the internal combustion engine will always be pursued. Increasingly stringent emission regulations are forcing manufacturers to downsize on engine displacement and increase specific power. By adding a turbocharger, the airflow throught he engine and hence the specific power can be increased.

Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2007. / The successful use of hydrofoil systems on catamarans, such as the Hysucat, led to the development of a similar foil system for a high speed trimaran. Firstly a mathematical model was developed to calculate the equilibrium planing conditions of a planing trimaran. This was then used in the hydrodynamic design of a fully planing trimaran with a design speed of 65 kn. The mathematical model was then modified to include the effects of added hydrofoils. This model was then used to design a hydrofoil support system for the planing trimaran. Towing tank tests were then performed on a scale model of the boat, with and without the supporting hydrofoil system. This was done to verify the theoretical design and to gather resistance data, which could then be compared to other boats. The results showed a notable improvement in efficiency of the boat with the addition of foils. The conclusion was made that with the addition of a well-designed foil system, hull efficiencies similar to that expected for the Hysucat, can be attained when the foil system is added to the trimaran. As this work was focused mainly on the high-speed performance of the boat, it is not certain how the boat will perform through the speed-range. It is therefore recommended that further testing be done, to determine the performance of the boat at lower speeds.

Thesis (MScIng)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: One of the areas of the fluid dynamic design of solar chimney power plants that has not been investigated sufficiently is the collector-to-chimney transition section of a single turbine layout. The transition section contains the turbine inlet guide vanes (IGVs) that support the whole chimney and guide the flow entering the turbine. The primary objective of the study was to determine the dependence of the loss coefficient of the section on inlet guide vane stagger angle and collector roof height. Experiments were done on a nominal 900 mm chimney diameter rig, with four combinations of two collector roof heights and two IGV stagger angles. Velocity components and pressures in the transition section were measured in three conical planes, respectively at the IGV exit and midway to, and just below the turbine position, using a five-hole pneumatic pressure probe. Very good agreement was found between experimental values and commercial CFD code predictions of flow angles, velocity components and internal and wall static pressures. The agreement between measured and predicted total pressure loss coefficient was reasonable when considering that most of the loss occurred in the weak wakes of the IGVs and in the very thin transition section wall boundary layers. The CFD code served to extend the predictions to a proposed full scale geometry. The losses are less than previously assumed. The study led to correlations between respectively loss and turning angle as dependent variables, and collector roof height and IGV stagger angle as independent variables. / AFRIKAANSE OPSOMMING: Een van die gebiede van vloeidinamiese ontwerp van sonskoorsteen kragstasies wat nog nie voldoende navorsing geniet het nie is die kollektor-tot-skoorsteen oorgangs gedeelte van `n enkel turbine opstelling. Die oorgangs gedeelte bevat die turbine se inlaat lei lemme (ILL) wat die hele skoorsteen dra en die vloei lei wat by die turbine ingaan. Die hoof doel van hierdie studie was om die verlies koëffisiënt van hierdie oorgangs gedeelte te bepaal as afhanklike van die ILL stel hoek en die hoogte van die kollektor se dak hoogte. Die eksperimente het op `n nominale 900mm deursnee skoorsteen skaal model geskied, met vier kombinasies van twee dak hoogtes en twee ILL stel hoeke. Snelheidskomponente en drukke is met `n pneumatiese 5-punt buis in drie koniese vlakke in die oorgangs gedeelte gemeet. Die vlakke was by die ILL se stert, halfpad deur die oorgangs gedeelte en by die turbine se inlaat. Baie goeie ooreenstemming is gevind met die eksperimentele waardes en `n kommersiële CFD kode se voorspellings van vloei hoeke, snelheidskomponente en interne- en wand statiese drukke. Die ooreenstemming tussen die gemete waardes en die berekende waardes vir die totale druk verlies koëffisiënt was redelik siende dat die meeste verliese van die klein versteurings van die ILL en die oorgangs gedeelte se dun-wand grenslae kom. Die CFD kode is toe ingespan om verdere voorspellings te maak vir `n voorgestelde volskaal geometrie. Die verliese is minder as wat daar van te vore voorspel is. Hierdie studie het gelei tot korrelasies tussen onderskeidelik verlies en draai hoeke as afhanklike veranderlikes, en kollektor dak hoogte en ILL plasings hoek as onafhanklike veranderlikes.

Thesis (MScIng)--Stellenbosch University, 2008. / ENGLISH ABSTRACT: Conventional pulse oximetry has limited accuracy in measuring blood oxygen saturation in low saturation and perfusion scenarios. This limits the application of pulse oximetry in patients su ering from peripheral vascular a ictions. A novel pulse oximetry system is presented in this study which proposes solutions to these low saturation and perfusion issues. The presented system was designed to overcome the low perfusion issues by inducing an arti cial pulse in the detected photoplethysmograph. A novel arterio-venous hypothesis was formulated to extract arterial and venous saturation data from this arti cial photoplethysmograph using arterial-to-venous compliance ratios. Sensor wavelengths were selected to provide high and low saturation accuracy, followed by an in vitro sensor calibration procedure. System performance was validated by means of in vivo human studies. In vivo results indicate good accuracy for high saturation, with limited accuracy in low saturation scenarios. The arterio-venous hypothesis was validated, indicating that venous saturation information can be extracted from the arti cial PPG. Although inconclusive, results indicate that the proposed system might be able to accurately monitor arterial and venous saturation in severe hypoperfusion scenarios with recommended hardware and calibration modi cations. It is recommended that further studies into the presented system's performance are conducted. / AFRIKAANSE OPSOMMING: Konvensionele 'pulse oximetry' sisteme het beperkte akkuraatheid tydens die meting van bloed suurstof saturasie in lae saturasie en perfusie gevalle. Dit beperk die bruikbaarheid van 'pulse oximetry' in pasiënte wat ly aan perifere vaskulêre siektes. 'n Nuwe 'pulse oximetry' sisteem, wat oplossings vir hierdie lae saturasie en perfusie beperkings voorstel, word in hierdie studie aangebied. Die voorgestelde sisteem is ontwerp om die lae perfusie beperkings te oorkom deur 'n kunsmatige polsslag in die 'photoplethysmograph' te induseer. 'n Nuwe arterio-veneuse hipotese is geformuleer om arteriële en veneuse saturasie inligting uit hierdie kunsmatige polsslag te onttrek deur middel van 'n arteriële-teenoor-veneuse styfheids verhouding. Die gol engtes wat gebruik is in die sensors, is spesi ek gekies om hoë en lae saturasie akkuraatheid te verskaf. 'n In vitro kalibrasie prosedure is gevolg om die sensors vir hoë en lae saturasie te kalibreer, waarna die werkverrigting van die sisteem getoets is deur middel van 'n in vivo validasie prosedure. Die in vivo resultate toon goeie akkuraatheid vir hoë saturasie, met beperkte akkuraatheid vir lae saturasie. Die arterio-veneuse hipotese is gevalideer, wat aandui dat veneuse saturasie wel uit die kunsmatige 'photoplethysmograph' onttrek kan word. Alhoewel die resultate wat in hierdie studie aangebied word nie omvattend of beslissend is nie, dui dit egter aan dat die voorgestelde sisteem dalk in staat kan wees om arteriële en veneuse saturasie in uiters lae perfusie gevalle te meet. Verbeteringe sal egter aan die sisteem aangebring moet word in terme van hardeware en kalibrasie, om 'n meer gestandardiseerde metings metode te verseker. Verdere navorsing oor die werkverrigting van die voorgestelde sisteem word ook voorgestel.

Thesis (MScIngwet)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: The diesel consumption of haul trucks deployed on opencast mines was investigated as a means of reducing the Total Cost of Ownership (TCO) of mining haul trucks. The conceptualisation of TCO and an introduction to the mining operation was presented as an introduction to the field of research. Thereafter, a review of the available literature revealed that linear programming, queueing theory and coast-down testing were applicable means of investigation. The relevant engineering sciences were applied and correlated with experimental and measured data from the Grootegeluk, Sishen and Thabazimbi mines operated by Kumba Resources Ltd (formerly known as ISCOR Mining). A cost-driver model for diesel consumption was formulated by exploiting the expert judgement of role players in the mining operation. A cost-driver model was developed for the Sishen, Thabazimbi and Grootegeluk mines. The cost-driver models were then modelled as a linear programming problem and solved using the student version of LINDO Optimization Software. The results were discussed and a universal diesel cost driver model was formulated by consolidating the individual diesel cost driver models. The operational cycle of haul trucks was simulated in order to quantify equipment utilisation and reduce diesel consumption of the mining vehicles. The operational cycle of haul trucks was modelled utilising queueing theory. The simulation of the queue network was implemented in Matlab using the next event advance method and was called Q Sim. Q Sim - - was utilised to investigate optimal fleet size and the economies of scale of haul truck capacity. The results of coast down tests were analysed in order to determine the effect of treating mining roads, with a bitumen product, on rolling resistance coefficient. Finally, recommendations for further research are proposed. This includes further refinement of the diesel cost-driver model, expanding the scope of application of Q_Sim in the mining operation and further investigation of dust reduction by bitumen products. / AFRIKAANSE OPSOMMING: Ondersoek is ingestel na die dieselverbruik van myntrokke sodoende die Totale Koste van Eienaarskap (TKE) van myntrokke te verminder. Die konsep rondom TKE is bespreek en 'n inleiding tot die mynybedryf is aangebied sodoende die verskeie aspekte in verb and te bring. 'n Literatuur studie het gevolg, wat aangetoon het dat lineere programmeering, toustaan-en loswieltoetse toepaslike navorsingsmetodes is om die nodige resultate te verkry. Daarna is hierdie ingenieurswetenskappe toegepas en 'n vergelyking is tussen die eksperimentele en gemete data van die Grootegeluk, Sishen en Thabazimbi myne getref. 'n Diesel koste-drywer model is opgestel met die insette van kundige rolspelers in die mynbou bedryf. Dit het gelei tot Koste-drywer modelle vir die Sishen, Thabazimbi en Grootegeluk myne. Die modelle is met lineere programmeering as probleemstelling daargestel en is deur middel van die studente weergawe van die LINDO optimaliseringssagteware opgelos. Die resultate was toe bespreek en daarvolgens is 'n universele diesel koste-drywer model opgestel deur die reeds-geskepte modelle te konsolideer. Die operasionele siklus van myntrokke was gesimuleer sodoende die benutting van toerusting te kwantifiseer en die dieselverbruik van myntrokke te verminder. Hierdie operasionele siklus was gemodelleer deur middel van die toustaan-teorie. Die simulasie van 'n toustaannetwerk was in Matlab gevoer deur Q_Sim te gebruik. Hierdie metode was gebruik om die optimale vloot grootte en die invloed van myntrokkapasiteit te ondersoek. Die ontleding van die loswieltoetse was gedoen om die invloed van In bitumen prod uk op rolweerstand te bepaal. Ten slotte is aanbevelings vir toekomstige navorsing bespreek. Dit behels die verder aansuiwerings van die diesel koste-drywer model, die uitbreiding van aanwending van die Q_Sim in die mynbou en 'n verdere ondersoek om stofvoorkoming in die mynbou te bewerkstellig deur die gebruikmaking van bitumen produkte.