Doctoral Degrees (Civil Engineering)

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Browsing Doctoral Degrees (Civil Engineering) by browse.metadata.advisor "De Wet, G."

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    Hydrologic-economic appraisal of inter-basin water transfer projects
    (Stellenbosch : Stellenbosch University, 2013-03) Van Niekerk, P. H.; Du Plessis, J. A.; De Wet, G.; Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.
    ENGLISH ABSTRACT: South Africa‟s hydrological and geographical characteristics, coupled with the location of a large part of its mineral endowment, required the development of the complex Vaal River Supply System, including inter-basin water transfer (IBT) projects which have been in operation for over twenty-five years. This research compares the actual water transfers of two such IBTs with their original, appraisal stage, predictions. Transfers are shown to be significantly less and also more variable than predicted. Further research reveals that the state of the receiving system has a large bearing on year-to-year decisions regarding transfers. Past appraisals, following what is called the Incremental Approach, do not adequately consider the likely future inter-basin transfer operating regime. Examination of six case studies, four South African, one Chinese and one Australian, shows that the Incremental Approach is still in general use – despite tools available for an improved approach. A new approach is proposed to upgrade estimations of variable costs associated with water transfers – often substantial life-cycle cost components of IBTs. The generally used unit reference value (URV) measure for appraising and ranking water resource projects in South Africa is also rooted in the economic theory of cost-effectiveness. This shows that the current approach is conceptually flawed; it fails to distinguish between water transfers and effectiveness outputs. The determination of the URV equation is expanded and improved. The upgraded appraisal approach, inclusive of the improved URV methodology, is named the Comprehensive Approach. A step-wise demonstration of the Comprehensive Approach is provided. Uncertainty regarding future water transfers and associated variable costs are provided for by stochastic simulation modelling. Decision analysis theory is applied to obtain the appropriate input value of variable costs. It is shown that the Comprehensive Approach can lead to an outcome significantly different from the Incremental Approach. The research provides new insights, placing water resource planning practitioners in a better position to recommend appropriate IBTs in future. These insights can also be transferred to the design of institutional and financial models related to IBTs, as well as the configuration and operation of supply systems including sea-water desalination projects.
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    A methodology for radical innovation : illustrated by application to a radical civil engineering structure
    (Stellenbosch : Stellenbosch University, 2008-12) Van Dyk, Cobus; Van Zijl, G. P. A. G.; Retief, J. V.; De Wet, G.; Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.
    Radical, far-beyond-the-norm innovation engages unknown developmental frontiers outside the familiar fields of standardised practice, requiring new and broad perspectives. This implies significant uncertainty during problem solution – the more radical, the greater the uncertainty. No systematic procedures for managing radical innovation exist. Research managers agree that traditional, standardised innovation approaches do not provide sufficient support for managers to cope with the degree of functional uncertainty typical of radical innovations. An efficient approach for delimiting and describing its uncertainties and managing the development process during the radical innovation process is sought. This thesis synthesizes a methodology for radical innovation from Systems Engineering and Management of Technology theory. Its application in a case study illustrates how it facilitates efficient strategic decision-making during radical innovation. Systems Engineering, by its comprehensive perspective, provides a valuable non-intuitive framework from which required radical innovation functionalities and uncertainties are identified, delimited, characterised and developed. Management of Technology concerns the core theory of technology; its perspective on technology provides the radical innovation process with a means of characterising and delimiting status, potential and uncertainty of functional, technological elements in the system. The resulting Radical Innovation Methodology is verified through application to an emerging renewable energy concept, the Solar Chimney Power Plant, which responds to a demand for innovation aimed at sustainable energy generation. The radically tall chimney structure required by the plant, proposed to stand 1,500 meter tall, serves as a fitting case for illustrating the methodology. Addressing and solving of challenges and uncertainties related to the radically tall structure and associated costs are required toward competence of this concept in a global energy market.