Abstract: In this project we study the exponential convergence of Markov processes to quasi-stationary distributions (QSDs) with applications. Quasi-stationary distributions are useful when it comes to understanding the behavior of stochastic processes which appear to be persistent over a long time period before reaching extinction. A review of the concept of stationarity and ergodicity is given. Next quasi-stationarity is defined. A simple example that illustrates quasi-stationarity is cons...
Abstract: In this thesis, new generalized families of distributions namely, Weibull Odd Burr III-G (WOBIII-G), Ristic-Balakhrishnan Odd Burr III-G (RBOBIII-G), Risti ´ c-´ Balakhrishnan Marshall-Olkin-G (RBMO-G), Exponentiated Half-Logistc Odd Burr III-G (EHL-OBIII-G) and Half-Logistic Odd Power Generalized Weibull-G (HLOPGW G) families of distributions are developed and studied in detail. Furthermore, the mathematical and statistical properties of these new families of distributions such ...
Abstract: Research on semiconducting metal oxide (MO) nanostructures is a fascinating field that has received massive interest due to their significant physical and chemical properties which can be useful in the development of highly efficient nanodevices. Incorporating impurities such as metal elements into the MO matrix offers tailored properties for various applications. Doped MO nanostructures exhibit modified structural, optical, electrical and morphological properties rendering th...
Abstract: Green nanotechnology is an innovative research field with emphasis on the development of methods that minimize the use of health hazardous substances for environmental remediation. This study reports on the biosynthesis of nanostructured multilayer graphene (MLG) and zinc oxide (ZnO) from natural extracts for environmental applications. ZnO nanoparticles are fabricated for the first-time using Ageratum Houstonianum leaf extract as an effective chelating agent. Besides this, a ...
Abstract: Kleinia longiflora belongs to the family Asteraceae and genus Kleinia (synonym Senecio) which comprises of about 40 species. Preliminary phytochemical investigation done on this plant showed the presence of terpenoids, tannins, alkaloids and flavonoids. The phytochemical investigation on the non-volatile compounds from the plant led to the isolation of a triterpenoid lupeol 1 (0.403 g), a flavonoid named isorhamnetin-5-O-α-rhamnopyranosyl (1'''-6'')-β-glucopyranose 11 (0.658 ...
Abstract: Current technologies for the detection and extraction of diamonds involve the repeti tive mechanical crushing of kimberlite ore, resulting in the damage of real diamonds. In particular, the breakage of large diamonds into smaller constituents decreases their value drastically, resulting in huge financial losses to mining companies. This dissertation focuses on testing a newly developed technology for the detection of di amonds in the kimberlite ore prior to crushing processes, thus...
Abstract: Continuous discharge of textile wastes such as dyes into the water bodies deteriorates the quality of water. Therefore, the removal of these materials from the wastewater should be a priority due to their carcinogenic properties, which pose a health hazard to both human beings and aquatic life. The use of advanced oxidation processes (AOPs) for example heterogeneous photocatalysis has been broadly studied due to their efficacy in the removal of such organic contaminants. Engin...
Abstract: Expansive soils tend to be fairly high in natural fertility and their unique morphology makes them quite interesting. Soils found in Serowe, Central Botswana, commonly exhibit variable degrees of periodic shrinking and swelling which often leave visible cracks and sometimes undulating micro-topography (gilgai) on the landscape. The use of expansive soils is often constrained due to severe management problems often associated with their physico-chemical properties. Therefore, basic ...
Abstract: This study was aimed at the synthesis of a library of heterocyclic compounds. The initial reactions involved the condensation of substituted acetophenones with benzaldehyde derivatives in either ethanolic solution of sodium hydroxide or by grinding method to yield chalcones. The percentage yield of the products was substantially higher by grinding method compared to that of ethanolic NaOH conventional method. It is noteworthy that the grinding technique is an environmentally f...
Abstract: Quinones form a large group of organic compounds with various applications in industry, biological systems, and pharmacology. They can capture an electron with kinetic energy exceeding zero and keep it for a longer time. The principal structure responsible for electron capturing in quinones is the para-benzoquinone, PBQ. Several studies have been carried out on PBQ and its molecular anion, but less attention has been paid to its derivatives upon capturing an electron. As such,...
Abstract: Surface photovoltage (SPV) spectroscopy is a powerful tool for studying electronic defects on semiconductor surfaces, at interfaces, and in bulk for a wide range of materials. Undoped and Cobalt-doped TiO 2 (CTO) thin films were deposited on Crystalline Silicon (c-Si) and Flourine doped Tin oxide (SnO 2 :F) substrates by chemical spray pyrolysis at a substrate temperature of 400 °C. The concentration of the Co dopant in the films was determined by Rutherford backscattering spectro...
Abstract: A series of ester and ether bridged compounds bearing the nitro and amino moieties were synthesized and characterized, in order to assess their ability to potentially serve as antibacterial agents against drug resistant bacteria. All the compounds were obtained at considerable yields while characterization techniques confirmed their successful synthesis. Furthermore, their antimicrobial assessments showed that all the compounds exhibited antibacterial activity against the Gram-nega...
Abstract: Let A and B be maximal monotone operators defined on a real Hilbert space H, and let Fix, (eqution found) and μ is a given positive number. [H. H. Bauschke, P. L. Combettes and S. Reich, The asymptotic behavior of the composition of two resolvents, Nonlinear Anal. 60 (2005), no. 2, 283-301] proved that any sequence (xn) generated by the iterative method, (eqution found) converges weakly to some point in Fix(JAμ JBμ). In this paper, we show that the modified method of alternating...
Abstract: Statistical distributions are important in modeling the real life of an item and therefore proper distributions that provide useful information for sound conclusions and decisions are needed. For that reason, the demand for developing new generalized distributions have become appropriate for data that have both monotonic and non-monotonic hazard rate functions. In this paper, we develop a new distribution called the Type IITopp-Leone-G Power Series (TIITLGPS) distribution by compou...
Abstract: The development of transparent conducting oxide materials has gained an increased interest in the scientific community for developing efficient low cost optoelectronic devices. The effect of Cd precursor on structural and optical properties of sol-gel synthesized Zn0.9Cd0.1O nanostructured films has been studied by using XRD, AFM, optical absorption and emission spectroscopic techniques. X-ray diffraction confirms the hexagonal wurtzite crystal structure of the deposited films and ...