Thesis (MScEng)--Stellenbosch University, 2012 / ENGLISH ABSTRACT: The construction project environment is dynamic and prone to change. Project change can be defined as any event that alters a project’s original scope, execution time or the cost of the works. Improper management of the projects’ changes could therefore adversely impact on the actual cost and duration of the project which may lead to project cost overruns and even claims and legal disputes. During the construction phase of a project, change affects every aspect of productivity – the planned schedules and deadlines, work methodology, resource procurement, as well as the budget and thus it could prevent the achievement of the project objectives. A project manager, therefore, wants to limit the number of change to a project. However, during a construction project there may be quite a number of changes. Managing a construction project is difficult, in that all the relevant information is rarely available at the initial stage of a project to enable one to plan and design the project accurately and make the best possible decisions. As information becomes available during the construction phase of the project, it can lead to various changes. Design errors or variations, unforeseen site conditions and vagueness in the original scope are but some of the reasons for change. No matter the size of the change, each alteration to the works has a cost, time and risk implication. Due to tight time constraints on most projects, every change requires quick, robust decision making, so as not to delay the project, which therefore results in changes not being comprehensively evaluated. Decisions are often made on intuition or experience, without an assessment of the risks involved or the influence on the cost of the project and without applying well-known project management techniques. The aim of this research was to determine what a change management process for a civil engineering project should look like, specifically the cost and risk management of changes. It investigated the current state of change management of construction projects in practice, by doing a case study and various interviews with project managers. Based on the findings of the research and the industry requirements, a model was developed for managing the costs and risks of changes. The Model was validated by means of an expert evaluation review. The change management model developed as part of this thesis can be used to analyse the cost, time and quality impact of the change, and to do a detailed risk assessment. The Model also reviews the proposed change in order to determine whether the change is necessary. It is a generic tool that can be used by engineers and their project team to enhance the management of changes that happens during the construction phase of a project for any civil construction project. / AFRIKAANSE OPSOMMING: Die konstruksie omgewing is dinamies en geneig tot verandering. Projek verandering kan gedefinieer word as enige gebeurtenis wat die projek se aanvanklike omvang verander of lei to verlenging van die tydsduur of vermeerdering van die koste van die projek. Wanbestuur van projek veranderinge kan ‘n nadelige impak op die projek kostes en tydsduur hê wat kan lei tot oorskryding van die begroting en selfs eise en regsdispute. Verandering kan elke aspek van produktiwiteit tydens die konstruksie fase van ‘n projek affekteer. Dit affekteer die beplande skedules, spertye, werk metodologie, hulpbron bestuur, asook die begroting. Dus kan dit verhoed dat die projek doelwitte bereik word. ‘n Projek bestuurder wil daarom die hoeveelheid en omvang van veranderinge beperk. ‘n Konstruksie projek kan egter heelwat veranderinge ondergaan. Om ‘n konstruksie projek te bestuur is moeilik aangesien al die relevante informasie selde beskikbaar is tydens die begin fases van ‘n projek wat nodig is om die beplanning en ontwerp van die projek so akuraat moontlik te doen en die regte besluite te neem. Soos informasie beskikbaar raak tydens die konstruksie fase van die projek, lei dit dikwels to verskeie veranderinge. Ontwerp foute of variasies, onvoorsiene terrein toestande en onduidelikheid oor die projek omvang is van die redes vir veranderinge. Ongeag die grootte van die verandering het elke wysiging tot die projek ‘n koste, tyd en riskiko implikasie. As gevolge van tydsbeperkinge vereis elke verandering vinnige en kragtige besluitneming om sodoende nie die projek te vertraag nie. Dit lei daartoe dat veranderinge nie omvattend geëvalueer word nie. Besluite word dikwels geneem op intuïsie of ervaring, sonder 'n beoordeling van die risiko's wat betrokke is of die bepaling van die invloed op die koste van die projek, en sonder die toepassing van erkende projek bestuur tegnieke. Die doel van hierdie navorsing was om vas te stel hoe 'n verandering bestuur proses moet lyk vir ‘n siviele ingenieurswese projek, spesifiek die koste en risiko bestuur van die verandering. Die huidige stand van verandering bestuur van konstruksie projekte in die praktyk is ondersoek deur middel van 'n gevallestudie en verskeie onderhoude met die projek bestuurders. 'n Model is ontwikkel vir die bestuur van die koste en risiko's van veranderinge gebaseer op die bevindinge van die navorsing en ook die vereistes van die bedryf. Die model is getoets met behulp van evaluering deur professionele ingenieurs. Die verandering bestuur model wat ontwikkel is as deel van hierdie proefskrif kan gebruik word om die koste, tyd en kwaliteit impak van ‘n verandering te analiseer, asook om 'n omvattende risiko assessering te doen. Die model hersien ook die voorgestelde verandering om te bepaal of die verandering nodig is. Dit is 'n generiese hulpmiddel wat deur ingenieurs en hul projek span gebruik kan word vir die bestuur van die veranderinge wat tydens die konstruksie fase van siviele projekte plaasvind.

Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: In a move towards cleaner and more sustainable energy systems, hydrogen as an energy carrier and hydrogen fuel cells as energy converters are receiving increasing global attention. Considering the vital role that platinum plays in the operation of hydrogen fuels cells, South Africa stands to gain enormously as the world’s leading platinum group metals supplier. Therefore, in order to benefit across the whole value chain, it is imperative to develop the capability to manufacture hydrogen fuel cell stacks locally. This project addresses this imperative, in part, by building a framework to evaluate the manufacturing performance of one of the more costly components of the hydrogen fuel cell stack. More specifically, this project builds a cost evaluation model (or cost model) for the manufacture of bipolar plates using micro milling. In essence, the model characterises manufacturing cost (and time) as a function of relevant inputs. The model endeavours to be flexible in accommodating relevant contributing cost drivers such as tool life and manufacturing time. Moreover, the model lays the groundwork, from a micro milling perspective, for a comparison of different manufacturing methods for bipolar plates. The approach taken in building the cost model is a fundamental one, owing to the lack of historical cost data for this particular process. As such, manufacturing knowledge and experimentation are used to build the cost model in a structured way. The process followed in building the cost model begins with the formulation of the cost components by reviewing relevant examples from literature. Thereafter, two main cost drivers are comprehensively addressed. Tool life is characterised experimentally as a function of cutting parameters and manufacturing time is characterised as a function of relevant inputs. The work is then synthesized into a coherent cost model. Following the completion of the cost model, analysis is done to find the near-optimal combination of machine cutting parameters. Further, analysis is done to quantify the sensitivity of manufacturing cost to design changes and production volumes. This attempts to demonstrate how typical managerial issues can be addressed using the cost model format. The value of this work must be seen in terms of its practical contribution. That is, its contribution to the development of the capability to manufacture hydrogen fuel cells locally. By understanding the effect of relevant input factors on manufacturing cost, ‘upstream’ design and development activities can be integrated with ‘downstream’ manufacturing activities. Therefore, this project supports the development of manufacturing capability by providing a mechanism to control cost throughout the process. / AFRIKAANSE OPSOMMING: In die soeke na skoner, meer volhoubare energie bronne word die fokus op waterstof, as energie draer, en waterstof brandstofselle, as energie omskakelaars, al meer verskerp. Deur die sleutelrol van platinum in die werking van waterstof brandstofselle in ag te neem, word Suid-Afrika, as die wêreld se grootste platinum verskaffer, in `n uitstekende posisie geplaas om voordeel te trek uit hierdie geleentheid. Om dus as land voordeel te trek uit die proses in geheel, is dit van kardinale belang om die vermoë te ontwikkel om waterstof brandstofsel stapels op eie bodem te vervaardig. Hierdie projek adresseer gedeeltelik hierdie noodsaaklikheid, deur `n raamwerk te bou wat die vervaardigingsoptrede van een van die meer duursame komponente van die waterstof brandstofsel stapel evalueer. Meer spesifiek, bou hierdie projek `n koste evaluerings model (of koste model) vir die vervaardiging van bipolêre plate deur die gebruik van mikro-masjienering. In wese kenmerk hierdie model vervaardigings kostes (en tyd) as `n funksie van relevante insette. Hierdie model poog om buigsaam te wees met die in ag neming van relevante bydraende kostedrywers soos buitelleeftyd en vervaardigingstyd. Daarbenewens lê hierdie model die grondwerk, vanuit `n mikro masjienerings oogpunt, vir die vergelyking van verskillende vervaardingings metodes vir bipolêre plate. Die benadering wat gevolg word in die bou van die koste model is fundamenteel as gevolg van die gebrek van historiese data vir hierdie spesifieke proses. As sodanig word vervaardigings kennis en eksperimentering gebruik om die koste model in `n gestruktueerde wyse te bou. Die proses gevolg in die bou van die koste model begin met die formulering van die koste komponente deur die hersiening van relevante voorbeelde vanuit die literatuur. Daarna word twee hoof koste drywers deeglik geadresseer. Buitelleeftyd word ekperimenteel gekenmerk as funksie van masjieneringsparameters en vervaardigingstyd word gekenmerk as `n funksie van relevante insette. Die werk word dan gesintetiseer in `n samehangende koste model. Wat volg op die voltooiing van die koste model is `n analise om die optimale kombinasie masjieneringsparameters te vind. Daaropvolgens word analises gedoen om die sensitiwiteit van vervaardigingskoste onderworpe aan ontwerpsveranderings en produksie volumes te kwantisfiseer. Dit poog om te demostreer hoe tipiese bestuursproblem geadresseer kan word deur die koste model formaat te gebruik. Die waarde van hierdie werk moet in die lig van die praktiese bydrae daarvan gesien word, menende, die bydrae tot die ontwikkeling van die vermoë om waterstof brandstofselle in Suid-Afrika te vervaardig. Deur die effek van relevante inset faktore op vervaardigingskoste te verstaan, kan ‘stroom-op’ ontwerp en ontwikkelings aktiwiteite geïntegreer word met ‘stroom-af’ vervaardigings aktiwiteite. Dus, hierdie projek ondersteun die ontwikkeling van vervaardigingsvermoëns deur `n meganisme te voorsien om kostes oor die omvang van die proses te beheer.

Thesis (MScEng (Industrial Engineering))--University of Stellenbosch, 2009. / Traceability systems are capable of both tracking and tracing parts. They offer many benefits to an organisation from assisting with recall applications to monitoring the everyday workings of a production line or supply chain. There are numerous methods able to act as traceability systems but only a few can be regarded as automatic and unique identifiers. Automatic traceability of individual entities is the future. It is already widely used by a number of leading companies throughout different business sectors and wide mass adoption is imminent. At present, they are slightly more expensive than the simpler technologies but once mass produced, the cost will come down. To completely understand how traceability systems are implemented, practical experience is required. When starting a traceability project, there are a lot of different options. The different systems offer their own set of advantages and some don’t work in certain environments. It was for this reason that The Decision Making Model was developed to assist users through the difficult initial stages of traceability implementation (i.e. choosing the system most suitable to a particular environment). This model was programmed in Excel and supplies the user with a number of questions regarding the environment the system would work in as well as the user’s requirements. The answers to these questions help the user work through the different types of traceability options to eliminate unsuitable choices. The result is an easy to use program designed with the ability to be upgraded as the technologies evolve.

Thesis (MScEng (Industrial Engineering))--University of Stellenbosch, 2008. / This thesis forms part of the AMTS Project on Investment Casting Capabilities for Light Metal Alloys in South Africa, the focus area being Rapid Tooling Development. Various issues of the investment casting process are being discussed from an industrial engineering point of view. These issues are related to the possibilities of improving the investment casting process’ lead times by shortening it while still maintaining affordable costs and required quality. Hereby the possibilities given by the newly developed “rapid technologies” are investigated. The focus is on Rapid Pattern Making as one of the most essential components for accelerated development of new products. Three of the most widely used layer manufacturing processes available in South Africa are selected for the study, namely Three Dimensional Printing – Drop-on-Bed (ZCorporation), Selective Laser Sintering (EOS) and Three Dimensional Printing – Drop-on-Drop (ThermoJet - 3D Systems). These three methods represent different materials; therefore different mechanical properties, different process economics as well as different technological characteristics. A standard benchmark part is used as a study base. Four patterns are produced by these three methods. A comprehensive measurement programme is conducted, followed by an appropriate statistical analysis and evaluation regarding accuracy and surface finish. Rapid Die Making is analysed with the possibilities of using additive methods for rapid tooling. Two dies are built with the same technology – Selective Laser Sintering (EOS), but in different materials. The same evaluation methodology is used for the statistical analysis and comparison. The two dies are injected with wax in order to produce the original benchmark part. The best wax patterns from each die are selected and evaluated, using the same methodology for analysis and comparison. The current state of Direct Shell Production is shortly discussed. The research concludes that RP&T techniques can successfully be used for creating accurate patterns and dies in order to shorten lead times in the investment casting process chain. Each RP&T process has its own set of advantages and disadvantages. All users should evaluate their requirements and the capabilities of the variety of techniques before deciding on a process to apply.

Thesis (MScEng (Industrial Engineering))--University of Stellenbosch, 2010. / ENGLISH SUMMARY: The research documents the development of a conceptual framework, the improbable circumstances strategic (ICS) framework, which guides organisations in the preparation for improbable circumstances. Four fields include: strategic management, innovation, systems thinking and complexity theories (black swans). The black swan principle was introduced with its applicability to the 2008 economic crisis. The black swan is an event which is retrospective in its predictability, highly improbable and carries extreme impact. There are various principles to cope with black swans which will now play a role in strategic management. Strategic management is studied from a systems thinking perspective which is a school of thought that strategy is a process which an organisation should follow from analysis, synthesis, implementation through to the operation phase. Some tools applicable to the analysis and synthesis phases were studied to give a greater understanding of the current field of strategic management. Innovation is an underlying principle which supports the strategic process. Innovation is a field which is currently not playing a large role in the strategy process. The principles of the innovation life cycle, innovation management and open innovation were studied to support the framework as well as create awareness around the advantages thereof within the field strategy. The dissertation uses aspects of these four fields to form the ICS framework. The framework consists of four phases: the analysis phase; the improbable event creation phase; the fragility analysis phase; and the synthesis phase. The first three phases run parallel with the current analysis phase of strategic management as the ICS framework is not designed to replace the strategic management process, but to add to it. The synthesis phase is where the design of the strategic plan for improbable circumstances takes place. Each phase sets out the inputs, requirements and deliverables needed for the successful implementation of the framework. Some tools for each of the phases are given, but they are given merely as a guideline as different organisations have the infrastructure for different tools. The framework is partially validated by being able to apply various tools to each phase, but the framework’s place in the field of strategy should be validated. The validation is done through interviews with eight industry experts in the four fields of study discussed. The results show a positive response with a call for future study through implementation, a tracking of the framework through this implementation and critical factors that arise from that. / AFRIKAANSE OPSOMMING: Hierdie navorsing beskryf die ontwikkeling van ‘n moontlike raamwerk; die onverwagte omstandigheids strategiese (ICS) raamwerk, wat organisasies met die voorbereiding vir onverwagte gebeure kan help. Vier areas word beskryf wat insluit: strategiese bestuur, innovasie, stelsels denke en kompleksiteitsteorie(swart swane). Die swart swaan beginsel is gebruik weens die toepasbaarheid daarvan op die ekonomiese krisis van 2008. ‘n Swart swaan is ‘n gebeurtenis wat terugwerkend voorspelbaar is, baie onwaarskynlik en ‘n groot impak het. Daar is verskeie beginsels om swart swane te hanteer wat vorentoe ‘n rol in strategiese bestuur kan speel. Strategiese bestuur word vanuit ‘n stelsels denke oogpunt bekyk wat strategie as die proses sien wat ‘n organisasie moet volg van analises, saamvoeging en implimentering tot die bedryfsfase. Sommige tegnieke wat op analises en sintese gerig is, is ondersoek om ‘n groter begrip van strategiese bestuur te gee. Innovasie is die onderliggende beginsel wat die strategiese proses ondersteun. Innovasie speel tans nie ‘n noemenswaardige rol in die strategie proses nie. Beginsels van die innovasie siklus, innovasiebestuur en oop innovasie is ondersoek om die raamwerk te ondersteun asook om ‘n bewuswording van die voordele daarvan in strategie uit te wys. Hierdie verhandeling bespreek vier fases van die ICS raamwerk: analises; die onverwagte gebeurtenis skepping; kwesbaarheids analises; en sintese fases. Die eerste drie fases word parallel met die bestaande analitiese fases van strategie bestuur as die ICS raamwerk gedoen en is nie ontwerp om die strategie bestuurs proses te vervang nie, maar om daartoe by te dra. Gedurende die sintese fase word die ontwerp van die strategiese plan vir onverwagte gebeure gedoen. Elke fase beskryf die toevoer, benodigdhede en aflewerbares nodig vir die suksesvolle implimentering van die raamwerk. Sommige hulpmiddels vir elk van die fases word gegee, maar slegs as ‘n riglyn want verskillende organisasies het die infrastruktuur vir verskillende hulpmiddels. Die raaamwerk word deels gekontroleer deur dat dit moontlik is om verskeie hulpmiddels op elke fase toe te pas, maar die plek van die raamwerk in die area van strategie moet gekontroleer word. Kontrole is gedoen deur dit met agt industrie kenners in die vier studie velde te bespreek. Die resultate toon ‘n positiewe reaksie vir toekomstige navorsing deur implimentering en die navolg van die raamwerk deur hierdie implimentering en die kritiese faktore wat daaruit mag voorvloei te doen.

Thesis (MScEng (Industrial Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: The world is facing an energy crisis with worldwide energy consumption rising at an alarming rate. The effects that fossil fuels have on the environment are also causing concern. For these two reasons the world is determined to find ‘cleaner’, renewable and sustainable energy sources. The Cape Winelands District Munisipality (CWDM) area has been identified as the study area for a bioenergy project. The CWDM project aims to determine the possibility of producing bioenergy from lignocellulosic biomass, and transporting it as economically as possible to a number of electricity plants within the study area. From the CWDM project a number of research topics were identified. The aim of this thesis is to determine the best location for one or more processing plants that will maximise the potential profit through the entire system. This is achieved by minimising the overall life cycle cost of the project. It takes into account costs from establishing and maintaining the crops, harvesting, transportation, conversion and generation; with a strong focus on the transport costs. In conjunction with a Geographical Information Systems (GIS) specialist and taking into account various factors such as electricity demand, heat sales and substation locations, 14 possible plant locations were identified. The possible supply points for each of the 14 plant locations were then analysed by GIS again to yield data in terms of elevation, road distances and slope. The transport costs were calculated using the Vehicle Cost Schedule (VCS) from the Road Freight Association (RFA) and fuel consumption calculations. It takes into account slope, laden and unladen transport and considers different transport commodities. These calculations together with the other associated costs of the life cycle are then combined with the results of the GIS into an EXCEL file. From this a transportation optimisation model is developed and the equivalent yearly life cycle cost of each of the 14 demand points are minimised by means of LINGO software. Initially runs were done for 2.5 MW capacity plants. From the high profit areas identified here, a single area was chosen and further runs were done on it. These runs were performed to determine the effect of different plant capacities on the life cycle costs, as well as how it affects the farm gate price that can be paid to the farmer. It also determined the effect of farmer participation at different plant capacities. The results indicate that it is currently possible to pay a farmer between R 300.00 and R 358.00 for a ton of biomass. It also revealed that with higher participation from farmers in the CWDM project, lower costs and higher farm gate prices will result, since the transport costs will be lower. Although all the costs within the life cycle are variable over time, the transport cost is the only cost that varies spatially and this will have a major effect on the overall system cost. The thesis found that generating electricity from woody biomass is feasible for all areas that were considered as well as for all variations considered during the sensitivity analysis. For the recommended plant size of 5 MW the transport of logs will be optimum. / AFRIKAANSE OPSOMMING: Die tempo waarteen energieverbruik wêreldwyd styg is ʼn rede tot kommer. Die nadelige effek wat fossiel brandstowwe op die omgewing het, is ook ʼn probleem. Hierdie twee redes is hoofsaaklik wat die wêreld dryf om ‘skoner’ hernieubare en volhoubare energie bronne te vind. Die Kaapse Wynland Distrik Munisipaliteit (KWDM) area is identifiseer as ʼn studie area vir ʼn bio-energie projek. Die doel van die KWDM projek is om die vervaardiging van bio-energie vanaf plantasies, die vervoer van hierdie bome sowel as die prosessering koste by die fabriek te bepaal en te evalueer. Vanuit die KWDM projek het `n aantal tesisse ontwikkel waarvan hierdie een is. Die doel van hierdie tesis is om die beste posisie vir een of meer prosesserings fabrieke te bepaal wat die potensiële wins van die KWDM projek sal maksimeer. Dit is ook gemik daarop om die ekwivalente jaarlikse oorhoofse lewenssiklus koste van die projek te minimeer. Dit neem die vestiging en onderhoud van gewasse, oeskostes, vervoerkostes en proseskostes in ag, met ʼn spesifiek fokus op die vervoerkoste. In samewerking met `ʼn “Geographical Information Systems” (GIS) spesialis en deur verskeie faktore, soos elektrisiteitsverbruik, inkomste vanaf hitte verkope en substasie posisies, in ag te neem is 14 moontlike fabriek posisies identifiseer. Verder is die moontlike voorsienings areas van elk van die 14 fabriek posisies weer deur GIS analiseer om resultate in terme van hoogte bo seespieël, padafstand en helling te verkry. Die vervoerkostes is verkry vanaf die “Vehicle Cost Schedule” (VCS) van die “Road Freight Association” (RFA), asook berekeninge wat die brandstof verbruik in ag neem. Hierdie kostes sluit in die effek van gradiënt, gelaaide en ongelaaide vervoer sowel as verskillende vervoer produkte. Hierdie berekeninge sowel as die ander kostes in die siklus en die resultate van GIS is kombineer in ʼn EXCEL leer. Hierdie data word dan gebruik om ʼn LINGO model te ontwikkel en die oorhoofse lewenssiklus koste van elk van die 14 fabriek posisies te minimeer. Optimering is gedoen vir 2.5 MW kapasiteit fabrieke. Uit die beste areas is een area identifiseer en verdere lopies is daarop gedoen. Die doel van hierdie lopies is om die effek van verskillende fabriekskapasiteit op die lewensiklus koste te bepaal, asook die effek daarvan op die prys wat aan die boer betaal word vir hout. Hierdie lopies is ook gebruik om die effek van boer deelname te bepaal. Die resultaat dui aan dat dit tans moontlik is om ʼn boer tussen R 300.00 en R 358.00 te betaal vir ʼn ton biomassa. Dit het ook gewys dat hoe meer boere deelneem aan hierdie projek hoe laer is die oorhoofse lewensiklus koste en hoe hoër is die prys wat betaal kan word vir hout aangesien die vervoerkoste laer sal wees. Alhoewel al die lewensiklus kostes veranderlik is oor tyd, is dit net die vervoerkoste wat ʼn ruimtelike komponent ook het en dit sal ʼn groot effek op die oorhoofse lewenssiklus koste hê. Die tesis bevind dat dit lewensvatbaar is vir alle areas in die studie om elektrisiteit op te wek vanaf hout biomassa, selfs al word die uiterse variasie in die sensitiwiteitsanalise gebruik. Vir die aanbeveling van ʼn 5 MW fabriek sal die goedkoopste vervoer opsie boomstompe wees.

Thesis (MScEng (Industrial Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: the potential to serve as a strategic economic driver for the country if a local processing and production industry could be successfully established. According to the US Geological Survey, conducted in January 2009, South Africa has approximately 14% of the world’s reserves in ilmenite and rutile, the two most important titanium-containing minerals, but no metal producing abilities. The only role players, Exxaro and Richards Bay Minerals, have smelting operations and produce an enriched titania slag, but all the slag is exported. The processing steps between titanium-containing minerals and the metal represent a significant portion of the total production costs and this study is chiefly concerned with recommending a more cost-effective alternative for these steps. The existing industrial process is archaic, cost and energy intensive, batch operated with unfavourable economics. A large number of internationally research initiatives are actively trying to address the problem of high production costs by searching for and developing alternative, more costeffective, processes. It was the purpose of this study to provide the decision making authorities with a ranking and evaluation of these alternatives to produce titanium metal. A 2-Phase Filtering System, based on both qualitative and quantitative techniques, was designed to assess, evaluate and formulate a final ranking. This evaluation was followed by a detailed sensitivity analysis of both local and global parameters. A total of 26 process alternatives were selected to be evaluated in this techno-economic evaluation. The complete ranking is given in Table 8.8, and the four leading process alternatives, based on this evaluation and the findings of the sensitivity analysis, are as follows: 1. CardQIT: The Canadian affiliate of Rio Tinto, QIT, developed a high-temperature titanium extraction process based on an electrolysis reaction, where molten titania slag is the cathode. 2. ArmITP: The Armstrong process is a continuous process that produces titanium in a very similar fashion as with the Hunter process, by the reduction of TiCl4 with sodium. TiCl4 vapour is injected into a stream of molten sodium to form titanium powder as the reaction product. 3. Kroll: This process was developed in the 1950s and the reduction step remains very much similar to the original process used by the USBM (United States Bureau of Mines). Two criteria played a big part in the unexpected high ranking of the Kroll process, and that were academic coverage, with almost 60 years of research, and the commercial readiness of an industrial process. 4. FFC: Solid pre-forms are pressed and sintered from pigment grade TiO2, to be directly electrochemically reduced to metallic titanium in a molten electrolyte of CaCl2. For future work, it is recommended that an additional filtering stage, a detailed profitability analysis, be added to the decision model. The top 4 alternatives, as mentioned above, should be used to estimate the cost-reduction potential as well as the capital investment and production costs based on process, industrial and economic engineering fundamentals. / AFRIKAANSE OPSOMMING: Titaan is deur die Suid Afrikaanse regering geidentifiseer as 'n mineraalhulpbron met die potensiaal om te dien as 'n strategiese ekonomiese drywer, indien 'n plaaslike verwerkingen verwaardingsbedryf suksesvol op die been gebring kan word. Volgens die US Geological Survey, wat in Januarie 2009 gedoen is, het Suid Afrika ongeveer 14% van die wêreld se reserwes in ilmeniet en rutiel, die twee belangrikste titaanhoudende minerale. Suid Afrika het egter geen metaal-vervaardigingsaanlegte nie. Die enigste twee rolspelers, Exxaro en Richards Bay Minerals, het smelteraanlegte en vervaardig 'n verrykte titaandioksiedkonsentraat, wat alles uitgevoer word. Die waardetoevoegingsaktiwiteite tussen die titaanhoudende minerale en die metaal verteenwoordig ‘n groot gedeelte van die produksiekoste van titaanmetaal en hierdie studie is hoofsaaklik daarmee gemoeid om ‘n meer koste-effektiewe aanbeveling te maak, m.b.t. dié stappe. Die bestaande bedryfsproses is argaïes, koste- en energieintensief, en is ontwerp as ‘n lot proses met ongunstige ekonomiese eienskappe. 'n Groot aantal internasionale navorsingsinstansies is aktief besig om oplossings te soek vir die probleem van hoë verwerking- en vervaardigingkostes, deur alternatiewe opsies te ondersoek en te ontwikkel. Die doel van hierdie studie was om vir die besluitnemingsgesag 'n rangorde en vergelyking van die alternatiewe opsies om titaniummetaal te vervaardig, te gee. 'n Tweeledige Filter Stelsel, gebaseer op beide kwalitatiewe- en kwantitatiewe tegnieke, is ontwerp om die rangorde te vorm, te bereken en te formuleer. 'n Sensitiwiteitsanalise is gedoen om die besluitnemingsparameters se invloed op die finale rangorde en uitslag te toets. 'n Totaal van 26 prosesse is geidentifiseer en gekies om aan hierdie tegno-ekonomiese evaluasie, te onderwerp. Die volledige rangorde word in Table 8.8 getoon, en die vier leidende prosesalternatiewe, gebaseer op die uitkomste van dié evaluering en die bevindinge van die sensitiwiteitsanaliese, is as volg: 1. CardQIT: Die Kanadese filiaal van Rio Tinto, QIT, het ‘n hoë-temperatuur titaan ontginningsproses ontwikkel, gebaseer op ‘n elektrolitiese reaksie, waarin gesmelte titaandioksiedkonsentraat die katode vorm. 2. ArmITP: Die Armstrong proses is ‘n kontinue opsie wat titaan produseer op ‘n baie soortgelyke wyse as die Hunter proses, deur die reduksie van TiCl4 met natrium, Na. TiCl4 damp word in ‘n gesmelte stroom natrium ingespuit om titaanmetaalpoeier te vorm as die reaksie produk. 3. Kroll: Die proses is ontwikkel in die 1950s en die reduksie stap wat vandag gebruik word is steeds soortgelyk soos die oorspronklike proses, aan gebruik deur die USBM. Veral twee besluitnemingskriteria het ‘n belangrike rol gespeel om tot die onverwagte hoë plasing van die Kroll proses te lei. Eerstens, akademiese dekking en die feit dat omtrent 60 jaar se navorsing in hierdie opsie ingepomp is en tweedens, die kommersiële gereedheid van hierdie prosesalternatief as ‘n volskaalse bedryfsproses. 4. FFC: Gegoe vorms van pigmentgehalte TiO2, word gepers en gesinter om die katodes te vorm wat dan direk elektrochemies gereduseer word tot titaanmetaal in ‘n gesmelte bad van CaCl2, as die elektroliet. Vir toekomstige werk word aanbeveel dat ‘n addisionele filtervlak, ‘n winsgewendheidsanalise, by die besluitnemingsmodel gevoeg word. Die vier prosesalternatiewe, soos hierbo genoem, kan gebruik word en vir elk moet die kostebesparingspotensiaal, die kapitaal insetkoste en die produksiekostes bereken word. Hierdie berekeninge kan gebaseer word op proses-, bedryfs- en ekonomiese ingenieurswese beginsels.

Thesis (MScEng (Industrial Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: As part of a growing trend in the medical industry of patient specific solutions, a need arises for means and methods that could grant surgeons the ability to improve their pre-operative planning, and help streamline their intra-operative proceedings relative to each individual patient. A suitable solution has emerged in the form of Additive Fabrication. Most of the traditional layer manufacturing technologies have been considered to be too expensive for medical application, and could not always be justified. However, more cost effective technologies, such as 3D Printing, have recently come to the scene and definitely require a fresh re-consideration for medical applications. In this report the research results are presented that look at the applications of 3D Printing in various fields of reconstructive surgery. Based on a variety of case studies the outcome strongly suggests that 3D Printing might become part of standard protocol in medical practice in the near future. / AFRIKAANSE OPSOMMING: Tans beweeg die mediese veld al hoe meer in die rigting van pasiënt uniekheid. Dit beteken dat behandeling begin weg beweeg van standaard prosedures en soveel moontlik aagepas word om aan te pas by elke unieke pasiënt. As deel hiervan ontstaan die behoefte by chirurge om hul operasies ook beter te beplan spesifiek tot elke individu, en sodoende te verseker dat die prosedures in teater so glad moontlik verloop. Daar is reeds tegnologië in die vorm van Addidatiewe Vervaardiging wat hierdie probleem aanspreek. Tot op hede was die finansiële implikasies vir meeste van die onderskeie tegnologië ‘n struikelblok wanneer dit kom by mediese toepassings. Tog, danksy meer koste effektiewe tegnologie soos 3D Drukwerk, is dit die moeite werd om weer op nuut te kyk na die moontlikhede wat die tegnologie kan bied. In hierdie verslag word daar gekyk na die verskillende toepassings van 3D Drukwerk in die veld van rekonstruktiewe chirurgie. Op grond van die resultate verkry vanaf ‘n wye verskeidenheid gevalle studies word die gevolgtrekking gemaak dat bekostigbare tegnologie soos 3D Drukwerk ‘n baie goeie kans het om in die nabye toekoms deel te word van standaard prosedure in die mediese praktyk.

Thesis (MScEng (Industrial Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: Concurrent and distributed business processes are becoming the norm in many organisations. Current modelling techniques do not address the problems faced by concurrent business processes sufficiently. We showhowmodel checking is applied to business processes to prove behavioural properties to address the aforementioned shortcomings. A method of abstraction is required to construct business process models that can be model checked. In this thesis we show the suitability of the Logical Thinking Process as an abstraction tool. We call the combination of the Logical Thinking Process and model checking the Complexity Alleviation Method (CAM). We apply CAM to two well-known supply chain and manufacturing problems, and insightful results are obtained. This leads us to the conclusion that CAM allows for the quicker modelling of business processes, as well as providing problem-specific and proven solutions in amanner not possible with simulation or other techniques. / AFRIKAANSE OPSOMMING: Gelyklopende en verspreide besigheidsprosesse word ’n alledaagse verskynsel in menigte instansies. Huidige modelleringstegnieke is nie in staat om die probleme geassosieer met gelyklopende besigheidsprosesse aan te spreek nie. Ons wys hoe model model verifikasie (“model checking”) toegepas word op besigheidsprosesse om gedragseienskappe te bewys en sodoende die voorgenoemde tekortkominge aan te spreek. ’nMetode van abstraksie word benodig ombesigheidsprosesmodelle, wat verifieerbaar is, te konstrueer. In hierdie verhandeling word die geskiktheid van die Logiese Denkproses (“the Logical Thinking Process”) as abstraksie gereedskap aangetoon. Ons noem die kombinasie van die Logiese Denkproses en model verifikasie Kompleksiteitsverligtingsmetodologie (CAM). Ons pas CAM op twee welbekende aanbodketting- en vervaardigingsprobleme toe en insiggewende resultate is verkry. Dit lei ons tot die gevolgtrekking dat CAM vinniger konstruering van modelle te weeg bring, sowel as probleem spesifieke en bewysbare oplossings verskaf wat nie moontlik ismet simulasie of ander tegnieke nie.

Thesis (MScEng (Industrial Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: The objective of this study is to develop a tool to enable manufacturing enterprises to develop a sustainability strategy suited to their specific business. In the study, the business reality that faces enterprises is discussed from a systems perspective. The concepts of sustainability and sustainable development are explored. Specific attention is paid to building mental models of what these concepts entail and the application thereof in individual manufacturing enterprises. Specific strategies and concepts, such as the Five Capitals Model, the Natural Step and Industrial Ecology, are highlighted. These tools and strategies are then consolidated into a ―Sustainable Roadmap‖, a tool to facilitate the development of a sustainability strategy. The ―Sustainability Roadmap‖ is tested by applying it to a case study. / AFRIKAANSE OPSOMMING: maatskappye sal help om ‗n onderneming spesifieke volhoubaarheids strategie te ontwikkel. In die studie word die besigheids realiteit van vervaardigingsmaatskappye bespreek van sistemiese perspektief. Die konsepte van volhoubaarheid en volhoubare ontwikkeling word verken. Spesifieke aandag word gegee aan die bou van modelle van wat hierdie konsepte behels. Spesifieke strategieë en modelle soos die ―Five Capitals Model‖, ―Natural Step‖ en ‖Industrial Ecology‖ word uitgelig. Hierdie konsepte en strategieë word dan saamgevat op ‗n sistematiese manier in ‗n ―Volhoubaarheids Padkaart‖, ‗n padkaart wat maatskappye kan volg om ‗n volhoubaarheids strategie te ontwikkel. Die ―Volhoubaarheids Padkaart‖ word getoets deur dit toe te pas op ‗n gevallestudie.