Browsing Articles: Department of Physical Sciences by Title
Now showing items 40-59 of 59
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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 ... -
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 ... -
Physicochemical Performance of Portland-Rice Husk Ash-Calcined Clay-Dried Acetylene Lime Sludge Cement in Sulphate and Chloride Media
(Hindawi, 2019-03)This paper reports leach and/or intake of SO42−, Cl−, Ca2+, Na+, and K+ from and/or into cement mortar cubes made from a novel cementious material in naturally encountered environmental simulated media. The paper also ... -
A preliminary study of Thermoluminescence of beta-irradiated SrAl2O4:Eu2+, Dy3+ phosphors
(2015)Eu2+ doped and Dy3+ co-doped strontium aluminate (SrAl2O4:Eu2+,Dy3+) phosphors were synthesized by the solution - combustion technique at 500 oC using urea as a reducer, a widely known method for preparing nano sized ... -
Properties of activated blended cement containing high content of calcined clay
(Elsevier, 2018-08)This paper presents findings of an experimental investigation on sodium sulphate (Na2SO4) activated calcined clay e Portland cement blends in sulphuric acid media. Calcined clays were blended with Ordinary Portland Cement ... -
Properties of activated blended cement containing high content of calcined clay
(Elsevier, 2018-08)This paper presents findings of an experimental investigation on sodium sulphate (Na2SO4) activated calcined clay e Portland cement blends in sulphuric acid media. Calcined clays were blended with Ordinary Portland Cement ... -
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 ... -
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 ... -
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. ... -
Review of Carbonation Resistance in Hydrated Cement Based Materials
(Hindawi, 2019)Blended cements are preferred to Ordinary Portland Cement (OPC) in construction industry due to costs and technological and environmental benefits associated with them. Prevalence of significant quantities of carbon dioxide ... -
Review of Carbonation Resistance in Hydrated Cement Based Materials
(Hindawi, 2019-01)Blended cements are preferred to Ordinary Portland Cement (OPC) in construction industry due to costs and technological and environmental benefits associated with them. Prevalence of significant quantities of carbon dioxide ... -
A Review on Pyroprocessing Techniques for Selected Wastes Used for Blended Cement Production Applications
(Hindawi, 2020-08)Pyroprocessing is an important stage in cement manufacturing. In this process, materials are subjected to high temperatures so as to cause a chemical or physical change. Its control improves efficiency in energy utilization ... -
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 ... -
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 ... -
Survey on Nanotechnology
(2019-07)Nanotechnology is a field where scientific knowledge and ideas emanating from the sub-atomic, atomic and molecular levels are applied in the manufacture of new and smart materials. Nanotechnology makes use of the novel ... -
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, ... -
Thermal Resistivity of Chemically Activated Calcined Clays-Based Cements
(Springer, 2017-10)The study investigated the effects of selected potential chemical activators on thermal resistivity of calcined clay based cement mortars. 0.5 M Na2SO4 and 0.5 M NaOH were used as activator solutions. The chemical ... -
Thermoluminescence of SrAl2O4:Eu2þ, Dy3þ: Kinetic analysis of a composite-peak
(Elsevier, 2016-12)The kinetic analysis of thermoluminescence of beta-irradiated SrAl2O4:Eu2þ,Dy3þ is reported. The glowcurve is dominated by an apparently-single peak. It has been demonstrated using a number of tests including partial ... -
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 ...
