ABSTRACT The high temperature superconducting cuprates show some non Fermi liquid behaviour in their normal state. Also there is no generally accepted theory of high temperature superconductivity. The BCS theory has failed to explain the superconductive state properties of the cuprate superconductors. GorterCasimir two uid model and London theory has been very useful before the BCS theory. Varma and his co-workers propounded a `marginal` Fermi liquid theory which explains the normal state pro...
ABSTRACT The advent of nanotechnology together with Biomedical Microelectro-Mechanical Systems (BioMEMS) for improved efficacy in treatment of cancer has resulted in the development of an implantable biomedical device for localized hyperthermia and drug delivery. This thesis work develops a mathematical framework based on relaxation losses of heating mechanism of magnetite magnetic nanoparticles synthesized with the Polydimethylsiloxane (PDMS) gel encasement. Numerical solution of the mathem...
A feasibility study of a conceptual nuclear design of a facility capable of producing high thermal neutron fluxes using isotopic neutron sources in a multiplying medium was carried out. The one-dimensional multigroup neutron diffusion equation was solved using the finite difference technique. A computer code SUNDES was written in FORTRAN 77 programming language and used to study the effect of reflectors, shielding materials and strength of isotopic neutron sources on the production lev...
ABSTRACT A popular model that have been used to study ferromagnetism is the Ising Model which is an arrangement of spins along a particular direction and with discrete values of +1. 1-D Ising model doesn't show a phase transition to the paramagnetic phase as opposed to the 2-D Ising model which shows a transition at a critical temperature. In this work, I have used Monte Carlo simulation method to study the 1-D quantum Ising model in a transverse eld at a nite temperature to obtain the critic...
ABSTRACT This research investigates the effects of bending on the electrical, optical, structural and mechanical properties of flexible organic photovoltaic (OPV) cells. Bulk heterojunction organic solar cells were fabricated on Polyethylene terephthalate (PET) substrates using Poly-3-hexylthiophene: [6, 6]-phenyl-C61-butyric acid methyl ester (P3HT: PCBM) as the active layer and Poly (3, 4-ethylenedioxythiophene) Polystyrenesulfonate (PEDOT: PSS) as the hole injection layer. All the organic...
ABSTRACT Organic-inorganic hybrid perovskite solar cells have attracted great attention in the photovoltaic research community in recent years due to its ease of processing, low cost of production, superb light-harvesting characteristics, and relatively high efficiency which make it more preferable over other existing solar cell materials. Lead-based perovskites (CH3NH3PbX3, X= Cl, I, Br) solar cells have recently attained a high efficiency of ~19.3% which far surpasses the efficiencies of m...
Abstract In this work, we review 3-dimensional gravity by canonically analyzing the Hilbert- Palatini action. We apply a time gauge used in 4-dimensional loop quantum gravity [14] to the simpler case of the 3-dimensional loop quantum gravity. By time gauge xing this Hilbert-Palatini action it leads to the Gauss constraints, the spatial dieomorphism constraints, the Hamiltonian constraint and a new constraint C. The gauge symmetries generated by this new constraints are spacetime dieomorphism ...
ABSTRACT The erodibility of soils from six different rainfall erosivity areas in Ghana were investigated. The soils were sampled and packed into wooden boxes maintained at 9% slope. Soil erosion was measured by applying simulated rainfall storms over the soil samples. The erodibility factor K for each soil type was calculated from USLE, K=A/EI30LSCP. The results showed a variability in erodibility factor values which ranged from 0.36 to 0.62. The physical and chemical properties of the soils ...
ABSTRACT In this work the potential of harnessing electricity from solar and wind sources in Ghana is evaluated both quantitatively and qualitatively. In this regard solar, wind and other relevant data were collected (over a period of one year) from various parts of Ghana. Detailed assessment of the capacity or potential of power production from hybrid solar-wind sources is done with the use of empirical mathematical formulae and the PRO VITUS model incorporated in the ‗ENERGY X‘ software...
Abstract The Maxwell equations of electrodynamics acquire an additional symmetry if one assumes the existence of hypothetical particles-magnetic monopoles, carrying a magnetic charge. The additional internal symmetry is the electromagnetic duality generated by the rotations in the space of electric and magnetic charges. In this project we revise the electromagnetic duality in his global aspect starting with the celebrated Dirac monopole, a singular solution in a slightly modified Maxwell the...
Abstract Femtosecond lasers represent an electromagnetic field with field intensities approaching and even exceeding atomic binding field. When irradiated on a target, the material responses change from linear to nonlinear within a very short time. In most situations nonlinear absorption dominates and can be used in micromachining of materials. In this work, analytical formulae are outlined relating laser and target parameters. This permits prediction of ablation conditions of materials. Ion...
ABSTRACT The thesis presents the modelling and simulation of free running semiconductor laser. The rate equations which were derived on the basis of the fact that there must be a balance between carriers that undergo transition and the photons generated and annihilated were simulated to examine what laser looks like when ran without positive optical feedback nor any optical injection. The result shows the photons get amplified due to stimulated emission but no oscillation of the output is ob...
ABSTRACT In this study, the complex interaction of surface runoff with the biomechanics of soil water transport and heat transfer rate is theoretically investigated using mathematical model that rely on the two phase flows of an incompressible Newtonian fluid (stormwater) within the soil (porous medium) and on the soil surface (runoff). The flow and heat transfer characteristics within the soil are determined numerically based on Darcy-Brinkman-Forchheimer model for porous medium coupled with...
ABSTRACT Chemical method is the most efficient and flexible method of hydrate control in offshore operations. In recent times, polymers and surfactants have been used to influence the kinetics of hydrate growth and coagulation. However, the traditional polar solvents are still relevant because of their ability to melt hydrates. Due to the large volume of polar thermodynamic inhibitors usually required in the field, this work examines the effect of hybrid hydrate inhibitors (HHI) comprising b...
ABSTRACT Density-Functional Theory (DFT) offers a simplification to electronic structure problems by using the electron density instead of the wave-function. Unlike the wavefunction which is a function of 3N variables (excluding spin) for an N-electron system, the density depends only on three variables, irrespective of the number of electrons in the system. While DFT, in principle, gives an accurate description of ground state properties, practical applications of DFT are based on approximat...