M. Phil. / Risk management comprises of risk identification, risk analysis, response planning, monitoring and action planning tasks that are carried out throughout the life cycle of a project in order to ensure that project objectives are met. Risk is a fact of life in all mining type projects. This research dissertation documents the risk management practices of an EPCM company involved in mining projects. Risk analysis techniques are discussed and the author goes deeper to examine what risk means to a project, and how the project team perceive, identify and quantify project risks. This dissertation uses a case study to focus on an EPCM firm‘s approach to risk management in the mining projects environment. This study aims to illustrate how the risks involved in a project have to be identified, controlled and managed. The purpose of this dissertation is therefore to act as an implementation risk management model for the case company and for use in a typical mining projects environment. Risk is an integral part of engineering projects, and it is necessary to manage the risks in order to ensure project success.

This research report is a techno-economic analysis of the nuclear project management capacity in South Africa. It will focus on the project development phases of the nuclear expansion programme. The author has nuclear engineering training background and also currently involved in the Eskom new build programme (Medupi & Kusile) and the coal refurbishment projects. The following thinking philosophy is used to structure this research report: * Project management practise for nuclear projects globally * Project management practise for major Eskom projects in South Africa * The differences between South Africa and international project management practises * Guideline for project management in the nuclear environment for possible implementation of the nuclear expansion programme. The project life cycle has different phases, namely, project setup and planning phase, project design and engineering phase, and project execution phase. The first two phases were discussed and analyzed in detail. The project execution phase was also discussed, however, due to the limited time, the execution phase will not be analyzed in detail. Further research is recommended on the execution phase. At the end of this research report, a guideline for nuclear project management is developed and associated with some recommendations. This guideline can certainly assist Eskom or other potential NPP developer to understand all the critical aspects in a nuclear expansion programme. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2014

This research report is a techno-economic analysis of the nuclear project management capacity in South Africa. It will focus on the project development phases of the nuclear expansion programme. The author has nuclear engineering training background and also currently involved in the Eskom new build programme (Medupi & Kusile) and the coal refurbishment projects. The following thinking philosophy is used to structure this research report: * Project management practise for nuclear projects globally * Project management practise for major Eskom projects in South Africa * The differences between South Africa and international project management practises * Guideline for project management in the nuclear environment for possible implementation of the nuclear expansion programme. The project life cycle has different phases, namely, project setup and planning phase, project design and engineering phase, and project execution phase. The first two phases were discussed and analyzed in detail. The project execution phase was also discussed, however, due to the limited time, the execution phase will not be analyzed in detail. Further research is recommended on the execution phase. At the end of this research report, a guideline for nuclear project management is developed and associated with some recommendations. This guideline can certainly assist Eskom or other potential NPP developer to understand all the critical aspects in a nuclear expansion programme. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2014

Ingeniero Civil / Este trabajo realiza un análisis de los índices de accidentabilidad presentados por contratistas de construcción, durante la ejecución de proyectos EPCM para la minería, a lo largo de un periodo de estudio de cinco años. Para contextualizar este análisis, se describe primero el proceso conducido por el contratista general a lo largo de un proyecto de este tipo y la influencia que tiene sobre el desempeño en seguridad durante su construcción. Así mismo, se presentan normativas aplicables, tanto nacional como internacionalmente, para definir los índices de accidentabilidad a utilizar en el estudio y sus relaciones. El análisis de los índices de accidentabilidad se realiza a través de la búsqueda de relaciones de dependencia con algunas características propias de los proyectos estudiados. Estas características incluyen ubicación geográfica, tanto por región como por país, el tipo de obras, la magnitud del proyecto en base a la cantidad de horas hombre empleadas y la condición de uso del terreno. Los resultados indican que el desempeño en seguridad durante la construcción de proyectos EPCM depende mayoritariamente de la ubicación geográfica de éstos. Esto, debido a las importantes diferencias observadas entre las cifras alcanzadas en distintas regiones y países, mostrando un desempeño bastante deficiente en lugares con alto desarrollo económico, en contraste al buen resultado en naciones en vías de desarrollo. Las cifras también evidencian que los índices disminuyen durante períodos de menor actividad económica y mayor desempleo, por el contrario la gran demanda de trabajadores es una de las causas más probables de los bajos desempeños en períodos de abundancia de proyectos. Finalmente se incluyen algunas recomendaciones, para mejorar el desempeño general en materia de seguridad y su diagnóstico, a través del diseño enfocado a la seguridad en construcción y en operación, la utilización de índices de desempeño positivo y otras.

Among all thermal energy storage (TES) systems, latent heat thermal energy storage (LHTES) attracts high interest due to its high energy density and high exergetic efficiency. Due to the high enthalpy of fusion and low cost, inorganic salts are becoming popular as phase change materials and are used as the storage media in LHTES systems. The main drawbacks for the inorganic salts are their low thermal conductivity and high reactivity above 500°C. Therefore, designing a cost-effective containment at these conditions with longevity is a challenge. Macro-encapsulation of the PCM is one way to solve both the PCM containment issue as well as the low thermal conductivity problem. However, finding a practically viable encapsulation technique is a challenge especially for temperatures above 500°C. In the present study, encapsulation techniques were investigated for two temperature ranges; 500°C – 600°C and 600°C above. Metallic encapsulation was adopted for the 500°C – 600°C temperature. Commercially available, low-cost carbon-steel tubes were used, and the encapsulation shape was cylindrical. A 200µm coating of Ni was applied to strengthen the corrosion resistance. For temperatures above 600°C, a novel approach involving the use of ceramic materials was investigated for encapsulating chloride based PCMs. Low-cost ceramics with excellent thermal and chemical stability under molten-salt conditions were identified as the encapsulants. The influence of sintering temperature on the reactivity of feldspar, ball clay, kaolin and the mixture thereof with molten sodium chloride was investigated. The results were used to develop an optimum ceramic capsule fabrication procedure, using a green ceramic body followed by sintering at 1190°C. An innovative sealing process of in-situ layered eutectic formation was introduced. Sealing was performed at a temperature above the eutectic melting point of the salt mixture but below the individual melting points of each salt. The fabricated capsule survived more than 500 thermal cycles without showing degradation in its thermo-physical properties. Alumina (99%) based capsule containing NaCl-KCl was tested successfully for 1000 thermal cycles with a PCM weight loss of less than 5%. A lab-scale setup was designed and constructed to test an industry scalable LHTES system suitable for supplementing heat to a steam-powered cycle. Metallic cylindrical capsules were used with a eutectic of sodium sulfate (Na2SO4) and potassium chloride (KCl), which melts at 515°C, as the PCM for energy storage. This system was modeled and validated with experimental measurements. The calculated ratio of exergy to energy efficiency was around 89% (for 380-535°C). Flow irregularities were found due to a bend in the flow channel. Therefore, flow conditioners were investigated. A modified system with the flow conditioners and radiation shields showed 98% exergy to energy efficiency ratio (for 495-535°C). The overall efficiency of the system, however, was found to be low due to the heat losses from the storage tank. Finally, a novel design of a TES system using spherical capsules is proposed with additional enhancement gained from the experimental work on the lab-scale LHTES system. The innovation of this design lies in the manufacturing process to forms multiple spherical capsules using sheet metals. The adoptability of this technique for higher or lower temperature LHTES applications depends on the properties of the selected sheet metal. Any formable sheet metal can be used depending on the compatibility with PCM and HTF.

A wireless local area network (WLAN) provides high bandwidth to users in a limited geographical area. This network faces certain challenges and constraints that are not imposed on their wired counterparts. They are: frequency allocation, interference and reliability, security, power consumption, human safety, mobility, connection to wired LAN,service area, handoff and roaming, dynamic configuration and the throughput. But the wireless medium relies heavily on the features of MAC protocol and the MAC protocol is the core of medium access control for WLANs. The available MAC protocols all have their own merits and demerits. In our research works, we propose a hybrid MAC protocol forWLAN. In the design, we have combined the merits of the TDMA and CDMA systems to improve the throughput of the WLAN in a picocellular environment. We have used the reservation and polling methods of MAC protocols to handle both the low and high data traffics of the mobile users. We have strictly followed the standards specified by IEEE 802.11 for WLANs to implement the designed MAC protocol. We have simulated the hybrid TDMA/CDMA based MAC protocols combined with RAP (Randomly Addressed Polling) for Wireless Local Area Networks. We have developed a closed form mathematical expressions analytically for this protocol. We have also studied the power control aspects in this environment and we derived a closed form mathematical expressions analytically for this power control technique. This hybrid protocol is capable of integrating different types of traffic (like CBR,VBR and ABR services) and compiles with the requirements of next-generation systems.The lower traffic arrival is dealt with the Random Access and the higher traffic arrival is with the Polling methods. This enables us to obtain higher throughput and lowmean delay performance compared to the contention-reservation-based MAC schemes. The protocol offers the ability to integrate different types of services in a flexible way by the use of multiple slots per frame, while CDMA allows multiple users to transmit simultaneously using their own codes. The RAP uses an efficient "back-off" algorithm to improve throughput at higher arrival rates of user's data. The performance is evaluated in terms of throughput, delay, and rejection rate using computer simulation. A detailed simulation is carried out regarding the maximum number of users that each base station can support on a lossy channel. This work has analyzed the desired user's signal quality in a single cell CDMA (Code Division Multiple Access) system in the presence of MAI (Multiple Access Interference). Earlier power control techniques were designed to assure that all signals are received with equal power levels. Since these algorithms are designed for a imperfect control of power, the capacity of the system is reduced for a given BER (Bit-Error Rate). We proposed an EPCM (Efficient Power Control Mechanism) based system capacity which is designed for the reverse link (mobile to base station) considering the path loss, log-normal shadowing and Rayleigh fading. We have simulated the following applications for the further improvement of the performance of the designed MAC protocol:Designed protocol is tested under different traffic conditions. The protocol is tested for multimedia traffic under application oriented QoS requirements. Buffer Management and resource allocation. Call Admission Control (hand-offs, arrival of new users). The adaptability to the variable nature of traffic.The propagation aspects in the wireless medium. The proposed MAC protocol has been simulated and analysed by using C++/MATLAB Programming in IBM/SUN-SOLARIS UNIX environment. The results were plotted using MATLAB software. All the functions of the protocol have been tested by an analysis and also by simulation. Call admission control function of the protocol has been tested by simulation and analysis in a multimedia wireless network topology and from analysis we found that at low traffic the throughput is high and at high traffic the throughput is kept constant at a reasonable high value. The simulation results also justify/ coordinate the analysis results. Dynamic channel allocation function of the protocol was tested and analysed and the coordinated results show that at low traffic, high throughput and at high traffic the throughput is constant. Buffer management function of the protocol simulation shows the results that the packet loss can be controlled to a minimum by adjusting the buffer threshold level at any traffic conditions. Maintenance of data transfer during the hand-offs function was simulated and the results show that the blocked calls are less during low traffic and at high traffic the blocked calls can be kept constant at low value. Thus, the proposed model aimed at having high throughput, high spectral efficiency, low delay, moderate BER and moderate blocking probability. We have considered a pico cell with a maximum of several users and studied the power efficiency of combined channel coding and modulation with perfect power controlled CDMA system. Thus our simulation of the "software radio" has flexibility in choosing the proper channel coders dynamically depending upon the variations of AWGN channel.