Browsing Articles: Department of Physical Sciences by Issue Date
Now showing items 1-20 of 59
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Cementing material from rice husk-broken bricks-spent bleaching earth-dried calcium carbide residue
(2012)A cementious material, coded CSBR (Carbide residue Spent bleaching earth Broken bricks and Rice husks), was made from dried calcium carbide residue (DCCR) and an incinerated mix of rice husks (RH), broken bricks (BB) and ... -
A prototype parabolic trough solar concentrators for steam production
(Jomo Kenyatta University of Agriculture and Technology, 2012)In this work, the potential for a solar-thermal concentrator to produce steam has been studied. Three parabolic trough solar concentrators (PTSCs) of dimensions: - aperture width of 1.2 m, Collector length of 5.8 m and ... -
Anti-Bacterialactivities And Phytochemical Screening Of Extracts Of Different Parts Of Thalictrum Rhynchocarpum
(2013)Parts of the plant Thalictrum rhyncocarpum are used in herbal medicine in Kenya to treat various infections. The aim of this study was to evaluate in-vitro anti-bacteria activities and phytochemical profiles of solvent ... -
Determination of Potassium Levels in Intensive Subsistence Agricultural Soils in Nyamira County, Kenya
(2013)Assessment of potassium levels in agricultural soils of Nyamira County, Kenya was necessitated by the observed progressive drops in maize acreage yields over the years despite use of phosphorus and nitrogenous fertilizers. ... -
Beneficiation of Iron in Thermal-Reduced Ilmenite by Magnetic Separation
(2013)ncreasing demands for Iron in countries development, and lack of conventional reducing agents has resulted into sourcing of alternative ways of beneficiating the iron ore. This paper reports on the study that was done ... -
Effects of Zeolites X and Y on the Degradation of Malathion in Water
(2013)The inclusion of both zeolites X and zeolite Y significantly affected the dissipation of malathion in water. In the fresh water, malathion degradation followed a pseudo-first order kinetics with concomitant half-life ... -
Phenolic and Monoterpenoid Mosquito Repellent Constituents of Headspace Vapors of Conyza newii
(2013-01)The plant Conyza newii has been reported to posses, mosquito repellent and fumigant toxicity properties. In this study headspace vapors emitted by the plant were obtained by adsorption on porapak Q® through headspace ... -
Chemical composition and mosquito repellency of essential oil of Conyza newii propagated in different geographical locations of Kenya
(John Wiley & Sons, 2014)Previously, essential oil of Conyza newii (Asterale: Asteracea, Oliv. & Hiern) growing in the northern part of West Pokot (35◦E, 1◦N) of Kenya was shown to be highly repellent [RD50 =8.9×10−5 mg/cm2, 95% confidence interval ... -
Thalictramine, A new alkaloid from Thalictrum rhyncocarpum (Dill & Rich) and its anti-bacterial activity
(2014)Thalictrum rhyncocarpum, a creeping plant with fern-like leaves, is used in herbal medicine to treat various infections in parts of Africa. Previously, we reported In-vitro anti-bacterial activity of different parts (root, ... -
Diffusivity of Sulphate Ion in Selected Ordinary Portland and Portland Pozzolana Cements Mortar
(Kenya Chemical Society, 2014)Cement is subject to degradation by aggressive media. This study investigated sulphate diffusivity in mortar made from selected Kenyan cements which included three brands of Ordinary Portland Cements (OPC) and three ... -
Diffusivity of Chloride Ion in Mortar Cubes Made Using Ordinary Portland and Portland Pozzolana Cements
(2014)Cement is subject to degradation by aggressive media. This study investigated chloride diffusivity in mortar made from Kenyan cements which included three brands of Ordinary Portland Cements (OPC) and three brands of ... -
Influence of alkaline earth metal cations; Ca2+, Sr2+ and Ba2+ on the structural and optical properties of MAl2O4: Eu2+, Nd3+ phosphors.
(2014)Eu2+ doped and Nd3+ co-doped MAl2O4:Eu2+, Nd3+ (M = Ca, Sr, and Ba) phosphors were prepared by a solution-combustion method. The obtained powders were investigated in terms of their phase composition, particle morphology ... -
Roles of doping ions in afterglow properties of blue CaAl2O4:Eu2+,Nd3+ phosphors
(2014-04)Eu2+ doped and Nd3+ co-doped calcium aluminate (CaAl2O4:Eu2+,Nd3+) phosphor was prepared by a urea-nitrate solution combustion method at furnace temperatures as low as 500 °C. The produced CaAl2O4:Eu2+,Nd3+ powder was ... -
Performance of Potential Pozzolanic Cement in Chloride media
(2014-04)The paper presents finding of the pozzolanic activity of calcined clays from selected regions of Embu County – Kenya. The results are also presented for the compressive strength development and Chloride ingress resistance ... -
Properties of blue emitting CaAl2O4:Eu2+, Nd3+ phosphor by optimizing the amount of flux and fuel
(Elsevier, 2014-04)Long afterglow CaAl2O4:0.03Eu2+, 0.03Nd3+ phosphor was prepared by solution-combustion synthesis. The active role of boric acid (H3BO3) as a flux in enhancing the Eu2+ photoluminescence and the effect of a varied amount ... -
Effects of Temperature on Ilmenite During Concentration of Iron in Laterites Using Charcoal and Separation using Magnetic Separation
(IJSET, 2014-06)Effect of temperature on ilmenite minerals found in laterites has been investigated. It was found that during reduction of iron minerals in laterites to magnetite using charcoal at temperatures of about 500-700oC, ... -
Investigating a Prototype Heat Exchanger for Steam Storage
(2014-07)A coiled tube single pass counter flow heat exchanger was designed and fabricated using locally available materials and its capacity to transmit heat to water to make steam was tested. The heat exchanger was part of ... -
Magnetic Concentration of Iron in Lateritic Soils from Kamahuha, Murang’a County, in Kenya using Carbon Monoxide Generated In-Situ
(IJSET, 2014-08)Chemical and Mineral Analyses of laterites from selected sites in Kamahuha area of Murang’a County, in the Republic of Kenya, have been carried out with particular interest in the levels of iron and the type of minerals ... -
A Prototype Steam Storage System for Power Production
(2014-08-01)Use of solar energy on a large scale is mainly limited to the sun duration hours, weather conditions and adequate solar thermal storage technology. A means of addressing this problem using local materials is provided. ... -
Combustion synthesis, characterization and luminescence properties of barium aluminate phosphor
(Elsevier, 2014-09)The blue-green emitting Eu2+ and Nd3+ doped polycrystalline barium aluminate (BaAl2O4:Eu2+,Nd3+) phosphor, was prepared by a solution-combustion method at 500 °C without a post-annealing process. The characteristic variation ...
