Browsing Doctoral Degrees (Applied Mathematics) by Title
Now showing items 3958 of 60

New exact solutions for neutral and charged shearfree relativistic fluids.
(2022)We study shearfree gravitating fluids in general relativity. We first analyse the integrability of the EmdenFowler equation that governs the behaviour of shearfree neutral perfect fluid distributions. We find a new ... 
New models for quark stars with charge and anisotropy.
(2014)We find new classes of exact solutions for the EinsteinMaxwell field equations. The solutions are obtained by considering charged anisotropic matter with a linear equation of state consistent with quark stars. The field ... 
New solutions for a radiating star.
(2018) 
Noncircularity of beams in the CMB polarization power spectrum estimation.
(2013)Precise measurements of the Cosmic Microwave Background (CMB) anisotropies have been one of the foremost concerns in modern cosmology as it provides valuable information on the cosmology of the Universe. However, an ... 
A numerical study of heat and mass transfer in nonNewtonian nanofluid models.
(2019)A theoretical study of boundary layer flow, heat and mass transport in nonNewtonian nanofluids is presented. Because of the diversity in the physical structure and properties of nonNewtonian fluids, it is not possible ... 
On new and improved seminumerical techniques for solving nonlinear fluid flow problems.
(2012)Most real world phenomena is modeled by ordinary and/or partial differential equations. Most of these equations are highly nonlinear and exact solutions are not always possible. Exact solutions always give a good account ... 
On paired decoupled quasilinearization methods for solving nonlinear systems of differential equations that model boundary layer fluid flow problems.
(2018)Two numerical methods, namely the spectral quasilinearization method (SQLM) and the spectral local linearization method (SLLM), have been found to be highly efficient methods for solving boundary layer flow problems that ... 
On singularly perturbed problems and exchange of stabilities.
(2015)Singular perturbation theory has been used for about a century to describe models displaying different timescales, that arise in applied sciences; particularly, models displaying two timescales, namely slow time and fast ... 
Optimisation of the population Monte Carlo algorithm : application to cosmology.
(2015)In this thesis we study the Population Monte Carlo (PMC) algorithm and utilise simulations to improve the efficiency of the algorithm by optimising the algorithm parameters. We then ap ply these optimisation results to ... 
Partial exchangeability and related topics.
(1991)Partial exchangeability is the fundamental building block in the subjective approach to the probability of multitype sequences which replaces the independence concept of the objective theory. The aim of this thesis is ... 
Probing the nature of dark energy with 21cm intensity mapping.
(2020)Two approaches to measure the BAOs (baryon acoustic oscillations) with optical and radio telescopes, namely; galaxy redshift and intensity mapping (IM) surveys have been introduced and discussed in the literature. Among ... 
Relativistic astrophysical models of perfect and radiating fluids.
(2019)Abstract available in PDF file. 
Relativistic radiating stars with generalised atmospheres.
(2010)In this dissertation we construct radiating models for dense compact stars in relativistic astrophysics. We first utilise the standard Santos (1985) junction condition to model Euclidean stars. By making use of the ... 
Role of Weyl tensor and spacetime shear in relativistic fluids.
(2021)The main gravitational theory in which we develop this work is general relativity. We study the role of the Weyl tensor in general relativistic fluid motion including the e↵ects of spacetime shear. Firstly we consider ... 
Scalar perturbations of Schwarzschild black holes in modified gravity.
(2017)This thesis is concerned with the physics related to scalar perturbations in the Schwarzschild geometry that arise in modifed gravity theories. It has already been shown that the gravitational waves emitted from a ... 
Thermal evolution of radiation spheres undergoing dissipative gravitational collapse.
(2014)In this study we investigate the physics of a relativistic radiating star undergoing dissipative collapse in the form of a radial heat flux. Our treatment clearly demonstrates how the presence of shear affects the collapse ... 
Transport on network structures.
(2013)This thesis is dedicated to the study of flows on a network. In the first part of the work, we describe notation and give the necessary results from graph theory and operator theory that will be used in the rest of ... 
Using epidemiological mathematical models to understand the transmission dynamics of bovine tuberculosis in buffalo and cattle populations.
(2015)In South Africa, buffalo are the maintenance hosts of Mycobacterium bovis (M. bovis), a pathogen that causes bovine tuberculosis in wildlife and domesticated animals. To understand the transmission dynamics of M. bovis, ...