ABSTRACT Lightning is an important component in the global electric circuit of the earth. It is a leading cause of outages in electric power and telecommunication systems, of forest fires and of delays in aircraft missions. A lightning sensor operating at a radio frequency of300 kHz was constructed ~d used to study the occurrence of lightning in and around the University of Ghana campus during thunderstonns. Rainfall figures during each thunderstonn were also recorded. Data was collected ov...
Abstract We have used ab initio density functional theory to study the coadsorption of N and O on Pt(100) and Pt(111) surfaces. Our calculations show that on Pt(100) the most favourable site is the hollow site for N and the bridge site for O, while for Pt(111) there are different possible N and O coadsorption geometries. On both surfaces the interaction between N and O is repulsive in nature.
ABSTRACT The study of the structures and properties of organic materials for organic photovoltaic (OPV) applications and their interrelationships is a rapidly growing field of research, involving interdisciplinary efforts at the frontiers of chemistry, solid state physics and materials science. These materials differ from the better-understood silicon solar cell based materials by the lack of long range three-dimensional translational periodicity in their atomic arrangements and also by their...
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 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 A year-long campaign that accounted for seasonal differences have been conducted to examine the levels, chemical composition and sources of ambient particulate matter in multiple neighbourhoods of varying socioeconomic status in Accra, Ghana. Between September 2007 and August 2008, simultaneous measurements of PM2.5 and PM10 aerosols at five monitoring sites in four neighbourhoods (Asylum Down, East Legon, Nima and James Town/Ussher Town) were done for one 48-hour period every six d...
Abstract We present theoretical results of the study of H2S adsorption on gold cluster Aun(n = 1, 5) using density functional theory with PerdewBurke-Ernzerhof (PBE) exchange-correlation energy functional. Minimum energy structures of the gold cluster along with their isomers are considered in the optimization process. H2S molecule is observed to adsorb on to the gold cluster. However, the adsorption energy decreases with increasing cluster size. The structure of the gold clusters are simila...
ABSTRACT The effectiveness of the water shield above the core and in the pool for shielding gamma rays and neutrons was investigated by measurements and calculations for a tank-in-pool type reactor, Ghana Research Reactor-1, GHARR-1. Experimental determination of y - dose rates were made using Radiation Alert Monitor-4 and halogen counter type J613 y probe with readout on y -radiation monitoring system of the control console and the microcomputer control system. The PC version of the one-dime...
ABSTRACT This dissertation presents the combined results of analytical, computational and experimental study of the effects of surface texture and nanoscale surface oxides on the optical and mechanical properties of silicon single crystals and MEMS thin films. The first part of this work is focused on the analytical modeling of the reflectance of flat and textured silicon substrates. The model was used to study the reflection behavior of textured silicon surfaces under non-normal incidence. ...
ABSTRACT Background: Health-Related Quality of Life is a multidimensional construct referring to patient’s perception of the impact of disease and treatment on their physical, psychological, social function and wellbeing. HIV and Tuberculosis are two diseases of public health importance and there is paucity of data on the quality of life of patients who suffer from these diseases in Nigeria. This study was carried out to measure, compare and identify factors affecting health-related quality...