ABSTRACT In this thesis, hot carrier relaxation dynamics in semiconductor quantum dots and quantum well structures have been investigated as the basis for improving on the efficiency of conventional solar cells to values between 40% and 60% beyond the Shockley and Queisser detailed balance limit of 30% hitherto. Two schemes have been employed to obtain the shift in efficiency: The first is multiple exciton generation which occurs in semiconductor quantum dots. The output current as a function...
ABSTRACT The level of water pollution by heavy metals ' (Cu, Xn, Co, Ni, As, Mn, Cd, Cr. !)hi in twelve selected water Dams in Osun state were determined in order to know their distribution and possible source into the dams. Their bottom sediment and water were colIected for analysis. The result in sediment showed that .the concentration of Manganese is high in all the dams with values ranging from 21,27-775.39mgkg and it spreads across all the locations. Cobalt was detected only at one. lo...
Abstract: Radiation emissions from the University of Ibadan National Institute of Radiation Protection and Research (NIRPR), physico-chemical properties measurement and insect’s fauna collection around the surrounding of the Institute were conducted for a period of six months (November, 2011-April, 2012). Radiation survey meter model (RDS-30) type was used to take readings along the immediate surroundings of the NIRPR surroundings. Soil samples were collected at five points in the study si...
Abstract : The study of movement of underground water helps to predict the extent of flow in as much as we can determine the volume rate among other things. Sand samples from river bed were used as porous media. a laboratory experiment was set lip to Iook at longitudutinal dispersion III term of volume of liquid flowing across a unit cross sectional area per unit time in these materials. Water was made to flow through a cylindrical pipe drilled sideways at intervals. Values of pressure were ...
ABSTRACT Two spectroscopic techniques: Laser-Induced Fluorescence (LIF) and Attenuated Total Reflectance Fourier-Transform Infrared (ATR-FTIR) spectroscopy and soil analysis were used to study and classify Anti-Malarial Herbal plants (AMHPs) from four locations (Abrafo, Jukwa, Nfuom and Akotokyere) in the Cape Coast metropolis. Deconvoluted peaks from the LIF spectra of the AMHPs samples showed compounds such as berberine, quercetin, flavanols presents in all the AMHPs samples. Principal com...
Abstract: Nitrate is one of the problematic and wide spread contaminations. Indiscriminate disposition of human and animal wastes in Nigeria especially in urban region, and lack of proper environmental sanitation geared the need for the monitoring of groundwater contamination. This research work monitored the concentration of nitrate and nitrate-nitrogen in portable water from wells in Odo Ado, Ado-Ekiti, Ekiti State, and examined the relationship between this concentration and the well dept...
ABSTRACT The essential role of radiotherapy is to ensure detection and treatment of breast cancers using appropriate doses, these seem not to harm patients under review. Unintended detriments in the treatment and the risk of secondary cancers are mostly associated with delivering much higher doses than planned dose. This study focused on using phantoms for the determination, and comparison of planned doses with actual doses delivered to the breast, during radiation treatment. Adelaide phantom...
ABSTRACT Thermal conductivity. toughness, cleavability tensile and bending strengths of Khqa senegalensis (Oganwo), Nauclea cliderrichii (Opepe), Triplochiton scleroxylon (Arere), Pycnanarhus angolensis (Akomu), Albizia zygia (Ayunre) grown in Ogun State, Nigeria were investigated to obtain preliminary data on these properties to guide utilization. The thermal conductivity was measured using fully automated unitherrn 6000 Guarded Hot Plate (-170 to 550'~) while the tensile and bending strengt...
ABSTRACT Wavelength modulation spectroscopy using second harmonic (2f) signals is one of the modulation techniques in absorption spectroscopy used to improve the absorption signal by noise reduction. This second harmonic (2f) signal has been simulated using MATLAB, a new approach based on numerical integration, to investigate the influence of normalized modulation amplitude, m and the optimal 2f signal was found to occur at m = 2.1. Experimentally, free molecular oxygen gas was measured at th...
ABSTRACT A DOAS system has been developed and deployed to determine horizontal concentrations of such pollutants as NO2, SO2 and O3 in Bologna, Italy and Tema, Ghana. Measurements were conducted in Italy during the winter season of March 2005 and in Ghana during the dry harmattan season in January 2008 and raining seasons in July and August 2008. Their average lineof-sight concentrations were determined by measuring the scattered solar radiation through three optical windows in the zenith and...
ABSTRACT A simple fibre optical design for reflectance measurements of plane surfaces has been developed and tested. The reflectance system was standardized with a PF10-03-P01-Plane mirror. Average reflectance from the plane mirror was 99.7%, 99.5% and 70.0% for the 1310 nm, 850 nm LED sources and 632.8 nm He-Ne laser respectively. Average reflectance decreased with decreasing wavelength. Steel and aluminium metal plates showed different trends in average reflectance values. The microscope sl...
ABSTRACT The movement of contaminated fluid from a solid waste landfill into a portable water aquifer located beneath is an example of unwanted underground flow. With the problem of limited portion of land available for building construction in the cities, coupled with the rise in price of good and accessible land, there IS a need for. quick and urgent solutions to environmental pollution that may be resulted from this problem In this research, a laboratory setup consisting of a big transpare...
ABSTRACT Radiation dose to bladder and rectum in the treatment of cervical cancer using high dose rate brachytherapy is a limiting factor to the delivery of the prescribed dose to the target. The objective of this study is to determine absorbed dose to the bladder and rectum (organs at risk) in the treatment of cervical cancer using multisource high dose rate brachytherapy treatment system in order to establish an in-vivo dosimetric and quality assurance protocol for patient treatment. A phan...
ABSTRACT In this study, the International Center for Theoretical Physics’ Region l Climate Model Version 4 (RegCM4) is used over the period 1998-2010, to study the dynamics of rainfall over West Africa. The study also attempts to understand the West African Monsoon (WAM) circulation and its characteristics. Global Precipitation Climatology Project precipitation (GPCP), Tropical Rainfa ll Measuring Mission (TRMM), global atmospheric reanalysis (ERA-Interim, ERAINT), RegCM4 winds and National...
Abstract Search for alternative materials required for shielding ionizing radiation has being on the increase for some period of time. Lead which is widely used is expensive, therefore researches has to be carried out on other materials. Clay has been suggested but it is not as effective as lead in shielding ionizing radiation. This work therefore studies the compression of clay samples at different pressures and thicknesses, so as to improve its shielding ability in the attenuation of ioniz...