Browsing Department of Chemistry by Issue Date
Now showing items 41-60 of 323
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Spectroscopic characterization of the metal cation siting and the adsorbate-cation interactions in copper (II) and cobalt (II) exchanged faujasite-X zeolite
(State University of New York at Binghamton, 2006)Toxic chemicals are abundant in the environment and their detection often requires very costly and time consuming methods. Where such molecules are able to interact with the transition metal cations, their characteristic ... -
Sodium X-type faujasite zeolite decomposition of dimethyl methylphosphonate (DMMP) to methylphosphonate: Nucleophilic zeolite reactions I
(Elsevier, 2006-06-20)Dimethyl methylphosphonate (DMMP), used extensively as a nerve agent simulant, strongly adsorbs in X-type faujasite zeolite and undergoes nucleophilic substitution by the supercage oxygens. Solid state magic angle spinning ... -
Linear, primary monohaloalkane chemistry in NaX and NaY faujasite zeolites with and without Na0-treatment: Zeolites as nucleophilic reagents II
(Elsevier, 2006-06-20)This work undertakes, we believe for the first time, a study of the chemistry of alkyl halides in Na0 treated zeolites. It concludes that untreated zeolites do nucleophilic chemistry to the degree that the host is electron ... -
The relationship between some chemical parameters and sensory evaluations for plain black tea (Camellia sinensis) produced in Kenya and comparison with similar teas from Malawi and South Africa
(Elsevier, 2006-08-01)Reliable and accurately measurable chemical parameters that can be used to estimate black tea quality are desirable in trade, research and breeding programmes. Using plain Kenyan black tea from 11 cultivars, which gave ... -
The relationship between some chemical parameters and sensory evaluations for plain black tea (Camellia sinensis) produced in Kenya and comparison with simila...
(Elsevier, 2006-08-31)Reliable and accurately measurable chemical parameters that can be used to estimate black tea quality are desirable in trade, research and breeding programmes. Using plain Kenyan black tea from 11 cultivars, which gave ... -
Effects of cation siting and spin–spin interactions on the electron paramagnetic resonance (EPR) of Cu2+ exchanged X Faujasite zeolite
(North-Holland, 2006-11-21)Copper(II) exchanged Na X Faujasite zeolite was cation exchanged at levels from one Cu(II) in 30 unit cells (0.033 Cu(II)/UC) to 38 Cu(II) per unit cell (38 Cu/UC) and was examined by continuous wave and two-pulse and ... -
Sustainability of smallholder tea growing in Kenya
(2007)Although tea was introduced in Kenya in 1903, Africans (natives) were barred from growing the crop until after independence in 1963 when the legislation was repealed. Africans started growing tea under the smallholder tea ... -
The use of green tea (Camellia sinensis) leaf flavan-3-ol composition in predicting plain black tea quality potential
(Elsevier, 2007-01-01)Reliable and quantifiable green leaf parameters for predicting black tea quality potential of tea bushes at the single bush stage are necessary to shorten tea breeding and clonal selection programmes. Green leaf flavan-3-ols ... -
The use of green tea (Camellia sinensis) leaf flavan-3-ol composition in predicting plain black tea quality potential
(Elsevier, 2007-12-13)Reliable and quantifiable green leaf parameters for predicting black tea quality potential of tea bushes at the single bush stage are necessary to shorten tea breeding and clonal selection programmes. Green leaf ... -
NPK (S) fertilizer use in commercially cultivated clone BBK 35 in different tea growing regions of Kenya: I. Experimental design and initial soil chemical properties.
(Tea Research Foundation of Kenya, 2008)An experiment was set up in five sites by superimposing on commercially grown plantations consisting of one popular tea cultivar, clone BBK 35 at Timbilil estate, Kericho; Changoi Estate, lower Kericho; Magura-Kipkebe ... -
NPK (S) fertilizer use in commercially cultivated clone BBK 35 in different tea growing regions of Kenya: II. Effects of nitrogen rates and plucking intervals on soil chemical …
(Tea Research Foundation of Kenya, 2008)One commercially and widely grown tea cultivar, clone BBK 35 was evaluated for changes in soil chemical properties at different N-fertilizer rates and plucking rounds in five different localities in Kenya. The soils in all ... -
Long term fertilizer use on high yielding clone S15/10: Tea yields
(International society of tea science, 2008)High production of young tender shoots of Camellia sinensis L. O. Kuntze to make tea beverages leads to soil nutrients depletion through harvested crop and leaching. The production can be sustained by replenishing the lost ... -
The role of Kenya Tea Development Agency Limited in the small-scale tea holder development in Kenya.
(International Society of Tea Science, 2008)The Kenya Tea Development Authority (KTDA) was formed in 1964 to take over the functions of the Special Crops Development Authority (SCDA), which had been set in 1960 to promote tea growing by indigenous Kenyans (Africans). ... -
Influence of region of production on clonal black tea chemical characteristics
(2008-05-01)Production of black tea from the same vegetatively propagated (VP) cultivars, in Kenya and Malawi, shows variations in both chemical composition and quality. Whereas it is possible to produce black teas with similar ... -
Productivity and nitrogen use of tea plantations in relation to age and genotype
(Elsevier, 2008-07-11)Lack of science-based knowledge on responses of tea bushes to nitrogen (N) in ageing tea plantations hampers the development of ecologically sound and economically profitable N-management strategies. It is hypothesized ... -
Effects of water stress on growth and water relations of young grafted tea.
(Tea Research Foundation of Kenya, 2009)The effects of soil water stress on some physiological parameters and dry matter partitioning (dm) were studied in grafted tea plants (Camellia sinensis L.) grown in containers and subjected to adequate and reduced water ... -
High concentrations of polycyclic aromatic hydrocarbons found in water and sediments of car wash and kisat areas of Winam Gulf, Lake Victoria-Kenya
(Springer-Verlag, 2009-01-09)Mean concentrations of selected USEPA priority polycyclic aromatic hydrocarbons (PAHs) in surface sediments and water samples from Car Wash and Kisat areas of Winam Gulf, Lake Victoria in Kenya have been determined ... -
Responses of clonal tea to location of production and plucking intervals
(Elsevier, 2009-07-01)Tea is cultivated in diverse environments causing yield and quality differences in its beverages. To maximise yields and quality, agronomic practices should be optimised. But agronomic recommendations are uniform in different ... -
Spartial and seasonal variations in concentrations of polycyclic aromatic hydrocarbons in water and sediment of Kisumu City Bay of Winam Gulf, Lake Victoria-Kenya
(2009-11-01)Seasonal and offshore concentration variations for selected sixteen priority pollutant polycyclic aromatic hydrocarbons (PAHs) in surface sediments and water of Car Wash and Kisat areas of Winam Gulf, Lake Victoria, ... -
Pretreatment with natural flavones and neuronal cell survival after oxidative stress: a structure− activity relationship study
(Journal of agricultural and food chemistry, 2010)Quercetin shows structural features that have been related to the antioxidant potency of flavonoids and also shows neuroprotection in different models of oxidative death. Because only a few studies have focused on the ...