Abstract: The presence of magnetic particles is considered in a magneto-hydrodynamic blood flow through a circular cylinder. The fluid inside the tube is acted by an oscillating pressure gradient and an external constant magnetic field. The blood temperature is assumed to change with the blood and particle velocities, and the whole study is based on a mathematical model that includes Caputo fractional-order derivatives. Solutions for the particle and blood velocities, and blood temperature d...
Abstract: The use of the millimeter wave (mmWave) spectrum and further exploration of sub mmWave has led to a new era in wireless communication, as the need for higher data rates grows. High frequencies, on one hand, incur a higher path loss, requiring an increase in antenna gain requirements. Metasurfaces, which emerge as a promising technology for mitigating path loss effects by utilizing 2D arrays of engineered meta-atoms resembling metamaterials that control the surface’s electromagnet...
Abstract: The increase in the number of linked technological devices, coupled with devices with new multimedia based services has resulted in the growing demand for high data rate communication and a spectrum crisis. Non-orthogonal multiple access (NOMA) is a promising candidate for better utilisation of spectrum and to address the high data demands in current and future communication systems. This work addresses the utilization of NOMA under power minimization and user admission strategies....
Abstract: Amidst escalating data traffic demands, the fifth generation (5G) of mobile communication has been launched to curb these demands by providing high data rates, decreased latency, increased network capacity and large bandwidth. The ambitious performance expected from the 5G cellular communication network is enabled by different key technologies including shifting towards the millimeter wave frequency band. However, the millimeter wave band is accompanied by limitations of signal pat...
Abstract: The minimal cost, high efficiency and low power consumption of the Vertical Cavity Surface Emitting Laser (VCSEL) gives it an additional advantage when used in applications like fibre optical communication systems to meet the growth of data communication traffic. However, development of VCSELs working at longer wave lengths (1.3- 1.55 µm) has been limited by the inherent material problem making VCSELs longitudinal single-modes emitters. These problems among commonly used fibre opt...
Abstract: Remote seismic nodes frequently experience failure because of the short lifecycle of lead–acid batteries. Even the use of solar cells is insufficient because these cells have low energy conversion and requires the deployment of relatively expensive solar energy harvesting systems at the node. The conventional solar energy harvesting system requires hardware upgrades and charging to sustain the power at the remote seismic node. Lead–acid batteries and Direct Current-Direct Curre...
Abstract: The demand for cooling has grown exponentially over the past century to meet economic development, availability, comfort and social needs, accounting for over 10% of the global electricity consumption and growing. Rising global temperatures have also contributed to the growing need for cooling in buildings. Cooling, is a very energy-intensive process that can account for 20% to 75% of a building's energy, depending on the building use. Solar photovoltaic (PV) driven air-conditionin...
Abstract: The use of the millimeter wave (mmWave) spectrum and further exploration of sub mmWave has led to a new era in wireless communication, as the need for higher data rates grows. High frequencies, on one hand, incur a higher path loss, requiring an increase in antenna gain requirements. Metasurfaces, which emerge as a promis ing technology for mitigating path loss effects by utilizing 2D arrays of engineered meta-atoms resembling metamaterials that control the surface’s electromagne...
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...