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...
Abstract: Two main classes of radio navigation systems are satellite and ground-based systems. Examples of such systems are eLoran deployed as a terrestrial system, and BeiDou, Galileo, GPS and Quasi-Zenith Satellite System (QZSS) deployed as satellite Navigation Systems. These systems have been investigated in different navigation use-cases using a hybrid receiver capable of receiving any navigation signal. The goal of this paper is to demonstrate LoRa’s capability as a signal of opportun...
Abstract: An ion sensitive field effect transistor can outperform conventional ion-selective electrodes. Thus, a zinc oxide (ZnO) nanowire field effect transistor (NWFET) pH sensor was fabricated and measured. The sensor contained a channel with 1.7×1018 cm-3 donor concentration and 100 ZnO nanowires in parallel, each with the following dimensions: 10 μm×120 nm×20 nm. The active channel is passivated with an 18 nm Al2O3 layer. The device was measured under a controlled environment with a...
Abstract: This review paper presents and analyzes previous studies on wingtip devices mainly to reduce induced drag on fixed-wing aircraft and drones. Some of the parameters discussed are the different types of winglets, cant angles, and adjustable wing structures. And these are compared against performance measures including reduced drag, fuel consumption, and improved endurance. This study aims to explore the optimized design of a wing that will give maximum drag reduction for fixed-wing d...
Abstract: Copper slag is generated when copper and nickel ores are recovered from their parent ores using a pyrometallurgical process, and these ores usually contain other elements which include iron, cobalt, silica, and alumina. Slag is a major problem in the metallurgical industries as it is dumped into heaps which have accumulated into millions of tons over the years. Moreover, they pose a danger to the environment as they occupy vacant land (space problems). Over the past few years, stud...
Abstract: Natural Esters (NEs) with a high proportion of Unsaturated Fatty Acids (UFAs) were used in this research. A Superior Insulating Fluid (SIF) is prepared by blending NEs like Baobab Oil (BAO) and Mongongo Oil (MGO) with a pure dielectric like Kerosene (KER) and subjected to ultrasonic wave treatment at 30 kHz. Then, accelerated heating of SIF is carried out in the presence of Kraft Paper (KP) and Copper Plate (CP) for 10 hours a day at 90 °C for 30 successive days. The deterioration...
Abstract: This simulation study explores sustainable improvements that could be made to a pine dust pyrolysis system to eliminate total dependence on external electrical energy supply and improve the yield of high-quality dry bio-oil. The components, stoichiometric yield and composition of oil, char and gas were modeled in ChemCAD using data from literature and results from biomass characterization and pyrolysis. A fast pyrolysis regime was used to increase the overall yield of dry oil fract...