Abstract: Copper slag is a hard material produced from smelting copper-bearing ores. Over the years, research has prioritized utilizing slag as a secondary source of base metals. This paper focuses on the grinding/milling of copper slag collected from the BCL Mine in Botswana to obtain a maximum amount of material in the desired size class with minimal energy consumption. This will then be followed by an integrated flotation and leaching approach of the desired size class material to recover...
Abstract: In spite of the numerous advantages of employing free space optical (FSO) communication systems as viable complementary platforms for next-generation networks, the presence of atmospheric disturbances such as fog and scintillations are major sources of signal impairment which degrade system performance. Consequently, it becomes imperative to investigate and contextualize the unique climatic conditions in those locations where FSO links are to be deployed. Statistical evaluation of ...
Abstract: The load variation during three-point bending (TPB) tests on prismatic Nestos (Greece) marble specimens instrumented by piezoelectric sensors is predicted using acoustic emission (AE) signals. The slope of the cumulative amplitude vs the predicted load curve is potentially useful for determining the forthcoming specimen failure as well as the indirect tensile strength of the material. The optimum artificial neural networks (ANN) model was selected based on a comparison of different...
Abstract: This paper presents the design and implementation of Modular Multilevel Inverter (MMI) to control the Induction Motor (IM) drive using intelligent techniques towards marine water pumping applications. The proposed inverter is of eleven levels and has the ability to control the speed of an IM drive which is fed from solar photovoltaics. It is estimated that the energy consumed by pumping schemes in an onboard ship is nearly 50% of the total energy. Considering this fact, this paper ...
Abstract: This paper reports the experimental investigation of the corona discharge activity of punga oil under the influence of a local magnetic field and different voltage profiles (AC and DC voltages) using fluorescent fiber sensor as well as UHF sensor technique. The corona inception voltage (CIV) of punga oil is higher under negative DC voltage followed by positive DC and AC voltage, with a marginal reduction in its CIV magnitude observed on the impact of external magnetic field. The do...
Abstract: In visible light communication(VLC),arrays consisting of a single or multi-colour light sources are employed for a dual purpose being: the provision of illumination and data transmission. Therefore, it is substantial to come up with efficient techniques for resource allocation. The aim of this thesis is to design and develop a multi-user colour-based optical spatial modulation VLC framework using a line-of-sight (LoS) model. An optimisation problem with the intention of minimising...
Abstract: Production of biodiesel from microalgae has received worldwide recognition as an alternative to petroleum diesel. The process involves culturing, harvesting, drying, extraction, transesterification and characterisation of the microalgae biomass to biodiesel. The research aimed to investigate the potential of Dunaliella salina microalgae inhabiting in Botash Company’s solar ponds Botswana for biodiesel production. Optimum salinity and nutrients concentrations that produced maximum...
Abstract: Solar energy is an abundant and clean resource. However, solar energy applications face challenges of low efficiency and high capital investments. To mitigate low efficiencies, electro-mechanical trackers that follow the sun path to enhance reception of solar energy are used. Usually these devices are complex in design. In this study, a simpler and less energy consuming dual axis solar tracker concept is designed and evaluated. A design process model consisting of the three main ph...
Abstract: Alumina-based ceramic composites have attracted many research interests for several decades due to their good mechanical properties and the abundance of alumina (Al2O3) raw materials. This study was aimed at investigating the mechanical properties, sliding wear properties and microstructure of alumina tungsten carbide-cobalt (Al2O3/WC-Co). In this study, Al2O3/WC-Co admixed powders were consolidated and densified via spark plasma sintering (SPS) technique at a holding time of 5 to ...
Abstract: This work presents a programmable toolkit that allows the design and implementation of a smart weather system(SWS) at a local level. The uPyCraft software development kit (SDK) was used to load the MicroPython code and scrap three weather values (surface temperature, relative humidity and atmospheric pressure) from the DHT11 and BME280 sensors connected to the ESP8266 microcontroller. The NetBeans SDK was used to develop the database management system using SQLite and Java programi...
Abstract: Documentation on the correct process parameters and component requirements for setting up efficient aluminum powder production systems capable of manufacturing powder that meets the requirements for the selective laser melting (SLM) process is not available due to its proprietary nature. This hinders powder metallurgy (PM) trainees in acquiring knowledge and skills needed in setting up such metal powder production systems. To address this challenge, powder requirements for the SLM ...
Abstract: The main purpose of this investigation was to study the potential application of Morupule fly ash for the removal of copper and nickel in wastewater. Batch and column study experiments were carried out by varying parameters such as pH, adsorbent dosage, contact time, temperature, bed height and flow rate. The data was fitted into the kinetic models, kinetic isotherms and the thermodynamic parameters to determine the nature of the process. Batch experiments showed a more energetical...
Abstract: This work presents machine learning methods, particularly artificial neural networks (ANN) and multivariate regression analysis (MVRA) to create a mathematical model that will be used to predict the blasting effects in a Debswana diamond mine. These effects include airblast, ground vibration and rock fragmentation. We compare results from ANN, MVRA and empirical formulas using coefficient of determinant (R2) and root mean square error (RMSE). The ANN model with one hidden layer, 14...
Abstract: Long Range (LoRa) is a popular low power wide area network (LPWAN) technology which operates in the Industrial, Scientific and Medical (ISM) frequency band transmitting information over ranges in excess of 20 km and 5 km in rural and urban landscapes respectively. This is of significance in applications where LoRa may be used as a terrestrial navigation system, or in any wireless sensor network (WSN) applications. A key system performance parameter for network planning and covera...
Abstract: Wear is a huge problem in the mining industry as it depreciates the assets invested. The industry is looking at efficient refurbishment technologies to repair its equipment so as to enhance its service life. This thesis focuses on the development of wear resistant clads via laser cladding (LC) process to mitigate the problem of degradations in slurry tailings’ pump impeller made of 304L stainless steel. A critical literature review indicates that Tribaloy T-800 and Stellite 6 pow...