ABSTRACT This thesis presented the surface modification of polydimethyl siloxane (PDMS) to enhance surface wettability and surface roughness. Physical and chemical modifications were performed on cured surfaces of PDMS and PDMS-based nanocomposites. Firstly, physical modifications were done by direct coating of PDMS-based substrates with biopolymers such as polyethylene glycol (PEG), poly lactic-co-glycolic acid (PLGA) and sodium alginate (SA). On the other hand, coatings were done with the ...
ABSTRACT Ground State structures of neutral Copper clusters CuN=3−6 were generated and optimised within the framework of the Density Functional Theory (DFT) using Generalised Gradient Approximation (GGA) and ultrasoft pseudopotential. The shapes and binding energies of the clusters obtained showed good agreement with other theoretical works, except for the trimer cluster which has the shape of an equilateral triangle rather than the isosceles triangle as reported in previous works. The opti...
Abstract Human body responds to physical activities, external temperature, external magnetic field, and other factors by homeostatically adjusting its blood flow in order to deliver nutrients such as oxygen and glucose to every organ in the body and allow them to function. Complications in this hemodynamic may arise due to acute coronary syndromes such as stenosis or arteriosclerosis leading to obstruction of coronary arteries. These complications do cause a change in the blood flow to the b...
Abstract The study explores the potential effects of the remote application of cyclic magnetic field to the female anopheles mosquitoes that carry malaria parasites. The goal is to develop a theoretical basis that can guide the cyclic activation of the magnetic field to induce the inactivity of the malaria parasite without killing the mosquitoes. The model considers the hemozoin within the malaria parasite as a cluster of magnetic nanoparticels. The potential effects of the applied magnetic ...
ABSTRACT We have studied a model for a non-collinear but coplanar antiferromagnetic spin texture on a two dimensional kagome lattice structure in the presence of DzyaloshinskiiMoriya Interaction (DMI). We observed some interesting topological properties in our system i.e. the presence of non-trivial edge state in the wave function. This non-trivial edge state, which mainly surfaced in the presence of the DMI, showed robustness against the external magnetic eld and thus can be further studied ...
ABSTRACT The development of inexpensive, non-toxic, high efficiency and earth-abundant solar absorbers is critical for terawatt scale implementation of photovoltaics. Cu2SnS3 is a promising earth abundant absorber material that is attracting attention recently for optoelectronic application including photovoltaic solar cells. However, very little is known about the relationship between structural and optical properties such as the absorbance, reflectivity, refractive index, extinction coeffic...
ABSTRACT Since the appearance of the first wind turbines at the end of the nineteenth century, wind energy has been considered to be a renewable energy source for not just developed countries but also developing countries as well. Thus, since 2004, there has been a steady rise in wind energy production worldwide, with substantial actively installed capacity in Africa. However, due to the fact that wind turbines are highly dynamic systems that are excited by stochastic loads from the wind, var...
ABSTRACT In this thesis, we present a theoretical study on the current-induced nucleation and propagation of antiferromagnetic skyrmionium. A skyrmionium, also known as 2π-skyrmion, is a vortex-like magnetic structure characterized by zero topological charge. We show by means of micro-magnetic simulation that an antiferromagnetic skyrmionium can be nucleated via a local injection of spin current with toroidal distribution. Our systematic study of the current-induced dynamics shows that a sp...
ABSTRACT We visited various locations during the time of our field exercise which include: Ekerekunta, Akpoha, Ogo ubi, Okpo ezi, Amaeta Enu. The present study area is bound within the latitude of 5055” N to 6° 0’ 0” N and longitude of 7055” E to 8° 1’ 0” E in the Southern Benue Trough within the Afikpo syncline and Abakaliki anticlinorium in south eastern Nigeria. The shale units underlie the bioturbated sandstones. Sedimentary structures were also observed in the study area, w...
ABSTRACT Studies of physico-mechanical and morphological properties of pure and -cellulose reinforced blends of polystyrene (PS) and poly (vinyl acetate) (PVAc) are reported in this work. The compression moulded articles of the blends of different compositions (10:90, 20:80, 30:70, 40:60, 50:50, 60:40, 70:30, 80:20 and 90:10, PS/PVAc) were tested for mechanical performance, absorption behaviour, void activity and morphological arrangements. Comparison of mechanical properties such as tensi...
ABSTRACT Combination-control of two or more systems which may have important application in Josephson junction ratchet array, and other physical systems has not been explored. Most of the theoretical framework is on combination synchronization, and the need for combination tracking control. In this paper tracking control of 2-D Duffing oscillator, 3-D Lorenz-Stenflo, 4-D Lorenz-Stenflo systems, as well as combination-tracking control of two, three, four and five systems evolving from differe...
ABSTRACT A Quantum Cascade Laser Open-Path System (QCLOPS) version 2 sensor has been set-up and used to measure water vapour in the troposphere. The QCLOPS version 2 sensor was compared with a commercial humidity sensor. A positive correlation of 71.46 % was established between the coefficient of variation of the version 2 sensor and the mass concentration of the commercial humidity sensor. Ten different wood species namely Kroma, Dwindwinaba, Esia,Yaya, Konkroma, Emire, Mango, Esakoko, Cocoa...
ABSTRACT Particle accelerators are often used for both ion implantation and ion beam analysis, therefore the accurate and precise knowledge of the energies of the accelerated ions is essential. From the analytical point of view, the energy of the accelerated ion needs to be known with high precision which can only be achieved through calibration. Ghana Atomic Energy Commission hosts a 1.7 MV tandem accelerator, at the Accelerator Research Centre (ARC). This facility uses ion beam techniques s...
ABSTRACT Small-scale (and artisanal) mining has been defined differently around the world. However, in Ghana, small-scale (gold) mining is defined as ―mining (gold) by any method not involving substantial expenditure by an individual or group of persons not exceeding nine in number or by a co-operative society made up of ten or more persons‖. The activities in the mining sector have increased in recent times and as at 2008, a total of 212 mining companies were awarded mining leases and ex...