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: 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: 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...
Abstract: This paper presents related literature review on drones or unmanned aerial vehicles that are controlled in real-time. Systems in real-time control create more deterministic response such that tasks are guaranteed to be completed within a specified time. This system characteristic is very much desirable for drones that are now required to perform more sophisticated tasks. The reviewed materials presented were chosen to highlight drones that are controlled in real time, and to includ...
Abstract: In this article, we investigate the effect of micro-organisms on the rate of corrosion of stainless steel and mild steel alloys. The three analytical techniques we will employ in measuring the rate of corrosion are the electrochemical impedance spectroscopy, cyclic polarization and the mass loss method. The test material used is the 316L stainless steel and the mild steel coupons. The microorganism we are going to use for this investigation is the sulphate-reducing bacteria (SRB). ...