ABSTRACT Various energy sources are utilized at present with a challenge of energy storage in many cases. The existing rechargeable storage batteries which include sodium-ion and lithium-ion have some limitations in their gravimetric capacities. This can be improved by incorporating Vanadium disulphide (VS2) due to its metallic properties at ground state. In this work we investigate the adsorption of lithium ions on the VS2 layered material. Research shows that intercalating lithium ions on a...
ABSTRACT Owing to the depletion rates of coastal limestone, the characterization of cementitious materials occurring on the dry land is important in order to assess their potential as alternative materials for the manufacture of cement. In this study, a naturally occurring terrestrial rock herein referred to as “Matisaa gray rock” has been studied to determine its potential for the manufacture of cement. Matisaa gray rock is found in Matisaa village, Kitui County, Kenya, and it covers an ...
ABSTRACT The school curriculum consists of formal, informal and non-formal dimensions. Formal dimension refers to official timetabled subjects such as Physics. Informal dimension is the school environment that influences a learner’s behaviour. Non-formal dimension refers to out of class activities such as field trips and science club activities. The common assumption is that participation in non-formal activities enhances perception and achievement in the formal curriculum. However, seconda...
ABSTRACT Public Universities in Kenya are key players in the training of physics teachers through the Bachelor of Education (Science) programme. However, the training is in need of reforms due to changes in content, educational media and technology in teaching of secondary school physics. Reviews of the programme in public universities have focused on content with little attention to methodology. Further, there is lack of coordination in key areas of training among the universities yet; secon...
Abstract Diurnal variation of vertical total electron content (VTEC) over Lagos, Nigeria (6.52° N, 3.399 E, dip latitude 3.03° S) during low solar activity period (2010) and a comparison with NeQuick-model-derived VTEC, are presented in this paper. VTEC generally increases from 0600 h LT and reaches its maximum value at approximately 1400 to 1700 h LT during all months considered. Our result shows that NeQuick model provide a good prediction during daytime and nighttime at Lagos, although s...
Abstract The electronic, optical and thermal properties of hexagonal and cubic phases of Ge2Sb2Te5 (GST) have been calculated using density functional theory (DFT) as implemented in the QUANTUM ESPRESSO computer package. GST is successfully applied in optical memory such as rewritable CDs and is a promising candidate for non-volatile electronic memory. In optical storage, the reflectivity contrast can be optimized towards the ultraviolet spectral range, thereby increasing data storage capacit...
Abstract This work comprises of several aspects of calcium-aluminate phosphor activated with rare earth metal ions i.e. (CaAl2O4:Eu2+, Nd3+, and Dy3+). In particular the luminescent and structural properties of the long afterglow CaAl2O4:Eu2+,Nd3+,Dy3+ phosphors prepared by urea-nitrate solution-combustion method were investigated. The solution-combustion method is more efficient because phosphors with high efficiency were obtained at low temperature (500 oC) in a very short period of time (5...
ABSTRACT Inflation is a period of an accelerated expansion of the universe. Cosmological perturbations are created by the amplification of quantum vacuum fluctuations of matter and metric perturbations during inflation. The equation of dynamics governing the evolution of cosmological perturbations within the cosmological model in a single field inflationary scenario takes the form of a standard non-linear second-order differential equation, whose exact analytical solution has not been obtaine...
ABSTRACT Rastrineobola argentea, (R. argentea) is a commercially important fish species in Lake Victoria, with a characteristically smaller size compared to the other fish and high surface moisture content. However the prevalent preservation method of the fish is open sun drying, in which the fish is laid uncovered on the ground for a prolonged period exposed to; contamination, attack by bacteria, molds, rodents, birds and adverse weather conditions. Often huge losses estimated at between 20 ...
ABSTRACT With the progressive decline of capture fisheries and human population upsurge worldwide, aquaculture is expected to play a great role in ensuring sufficient fish in the market. Thus, aquaculture is promoted by world food production agencies and governments, and has experienced significant growth. However, for African countries such as Kenya, aquaculture production is disproportionately lower than capture fisheries. Thus, there is urgent need to improve aquaculture production in thes...
Abstract Measurement of equatorial ionospheric absorption made by the A3 Method for quiet conditions near a period of maximum solar activity (1979 to 1981) are used for a detailed examination of Absorption of Radio Waves in equatorial Ionosphere. Assuming an index law of the form L. 1.Cos"for the absorption (x being zenith angle of the sun). the diurnal and seasonal characteristics of the variation are obtained for two frequencies (4.9 Mhz and 7.1 MHz) and compared with existing theories. Pro...
ABSTRACT Despite many buildings have fire fighting systems installed in them; many people are still losing their lives and properties due to fire accidents. In this research, an automatic cost effective device for the detection and control of fire has been designed and constructed. The system has an additional feature of sending signal to a pump/sprinkler through a relay. It is made up of two sensors, microcontroller, buzzer and a controlled fire fighting equipment (pump/sprinkler). LM 3...
ABSTRACT The earth‟s surface is affected by three main types of radiation from the sun: global solar (or total), beam (or direct), and longwave (or indirect) radiation. Global solar radiation is composed of direct and indirect radiation. Approximately 99% of the total radiation from the sun that reaches the earth is beam radiation, which has a wavelength range of 0.29 to 3.9 μm and is not subjected to interference from any interspatial matter. The remaining 1% is longwave radiation, which ...
Abstract This thesis discusses the development, design, fabrication and testing of spectrally selective beamsplitting absorption filters which can decouple quantum and thermal convertors to improve conversion of the total solar spectrum to useful energy.
Abstract Precipitable Water Vapour (PWV) is the amount of water vapour in the atmospheric column above a location equivalent to the amount of liquid precipitation that would result if all the water vapour in the column was condensed. Water vapour is the main source of opacity in the Earth’s atmosphere at infrared and millimetre to sub-millimetre wavelengths. The Event Horizon Telescope (EHT) is a large network of millimetre to sub-millimetre telescopes across the globe that is used to image...