Articles: Department of Physical Sciences: Recent submissions
Now showing items 41-59 of 59
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Structural and luminescence properties of SrAl2O4:Eu2+,Dy3+,Nd3+ phosphor thin films grown by pulsed laser deposition
(Elsevier, 2015-09)Thin films of Eu2þ doped and Dy3þ,Nd3þ co-doped Strontium Aluminate (SrAl2O4:Eu2þ,Dy3þ,Nd3þ) phosphors were grown on Si(100) substrates by a pulsed laser deposition (PLD) technique using a 266 nm Nd:YAG pulsed laser under ... -
Structure,morphologyandopticalpropertiesofundopedand MN-doped ZnO(1 x)Sx nano-powderspreparedbyprecipitation method
(Elsevier, 2015-08)The undopedandMn-dopedZnO(1 x)Sx nano-powders weresuccessfullysynthesizedbyprecipitation method withoutusinganycappingagent.Itsstructure,morphology,elementalanalysis,opticaland luminescence propertiesweredeterminedbysc ... -
Effect of Ga3+ and Gd3+ ions substitution on the structural and optical properties of Ce3+-doped yttrium aluminium garnet phosphor nanopowders
(John Wiley & Sons, 2016-01)ABSTRACT: The structural and optical properties of commercially obtained Y3Al5O12:Ce3+ phosphor were investigated by replacing Al3+ with Ga3+ and Y3+ with Gd3+ in the Y3Al5O12:Ce3+ structure to form Y3(Al,Ga)5O12:Ce3+ and ... -
Trap characteristics of UV-activated Y3(Al,Ga)5O12:Ce3+phosphorsA
(Elsevier, 2015-12)tThis paper reports on the trap characteristics of commercially obtained Y3(Al,Ga)5O12:Ce3+phosphorpowder. The effects of UV irradiation time and different heating rates have been discussed using differentthermoluminescence ... -
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 ... -
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, ... -
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 ... -
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 ... -
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 ... -
Concentration of Laterites Using Biomass
(Kenya Industrial Property Institute, 2015-06-11)A method of concentrating iron in laterites to make the iron extraction process economical is disclosed. Concentration using biomass yields higher levels of iron by using appropriate ratio of biomass: laterites. The ... -
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 ... -
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 ... -
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. ... -
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 ... -
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 ... -
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 ... -
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 ... -
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 ... -
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. ...
