Browsing by Author "Kuria, Kamweru Paul"

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Effect Of Electric Field In The Soil On The Germination And Growth Rate Of Rosecoco Beans Plant
(Research journali, 2020-01) Evance, Odiwour; Stanislous, Mutunga; Kanyago, Gitonga Anthony; Kuria, Kamweru Paul
This study shows the effect of electric field on the germination and growth of bean plants. Rose coco beans was chosen because its growing rate is fast and it’s a common food plant. An electric field was applied in the soil and is expressed in terms of electric energy density created within pairs of copper plates with different polarities (-ve and +ve) forming electric impulse with 9V DC current at room conditions for 6 hours a day. A control sample was treated similarly except with no electric field applied. The growth parameters investigated were the germination rate and the heights of the stems and were recorded after every 4 days. The obtained results shows a positive effect on the germination of about 27.8% positive deviation and improved height gain rate of 32.1%. This data shows that electric field could have an effect of awakening seed dormancy which result to faster germination, and positively influence other biochemical processes resulting to higher growth rates.
Optical and scanning kelvin probe microscopic characterization of sol-gel synthesized aluminum doped zinc cobalt ferrite nanoparticles
(academic Journals, 2020) Sabastine, Butembu; Akou, Osamong Gideon; Kuria, Kamweru Paul; Mwangi, Gichumbi Joel; Ndiritu, Francis
In this work, Zn1-xCoFe2AlxO4 (x=0, 0.2, 0.4, 0.6, 0.8 and 1.0) ferrites were synthesized using the sol-gel method. XRD analysis was done and confirmed the formation of spinel structure, where the particle size and lattice parameter decrease with increase of aluminum concentration. This may be attributed to a shift of the bigger Al3+ ions, from the tetrahedral to the octahedral sites, interchanging with smaller Zn2+ ions and that consequently result to a decreased unit cell size. The Scanning Kelvin Probe Microscopy (SKPM) showed that the work function average ranges between 200 and 680 mV for the different concentration of aluminum in the samples. Fractural analysis indicated a small fracture between the samples of different ratios which can be attributed to the method used to prepare as well as the shifting of the Al3+ ions. The UV-vis spectroscopy showed variation of energy gap with increasing aluminum concentration, and an increased optical absorbance as the Al3+ ions were introduced in the samples.
Spinel ferrites gas sensors: a review of sensing parameters, mechanism and the effects of ion substitution
(Taylor & Francis Group, LLC, 2021-09-03) Njoroge, Muasya Alex; Kirimi, Nixon Mutwiri; Kuria, Kamweru Paul
There is an increasing demand of highly sensitive, stable and highly selective gas sensors to detect toxic gases. This is inspired by the need to monitor the concentration of these gases in order to guarantee humans, animals and environmental safety. Metal ferrites (AFe2O3, where A is a metal) based sensors are paramount in this field of sensing. Among the gases detectable using metal ferrites includes carbon monoxide (CO), liquefied petroleum gas (LPG), hydrogen sulfide (H2S), petrol and methane (CH4). This reviews presents various parameters which plays key role in the design of ferrite gas sensors. They include; operating temperatures, dopants, grain size, particle size, selectivity, surface area, concentration of the gas, sensitivity as well as recovery time. In addition, the various methods which are used to synthesize ferrite gas sensors are briefly explained. Key considerations in the designing of excellent ferrite gas sensors such as calcination temperature, working temperature, dopants, and concentration as well as optimization condition among others are outlined. In addition this paper reviews the various metal ferrites such as nickel ferrites and nickel doped ferrites, cobalt and cobalt doped ferrites, zinc and zinc doped ferrites, magnesium and magnesium doped ferrites among others that have been researched as gas sensors.
Spinel ferrites gas sensors: a review of sensing parameters, mechanism and the effects of ion substitution
(Taylor & Francis, 2021-09) Njoroge, Muasya Alex; Kirimi, Nixon Mutwiri; Kuria, Kamweru Paul
There is an increasing demand of highly sensitive, stable and highly selective gas sensors to detect toxic gases. This is inspired by the need to monitor the concentration of these gases in order to guarantee humans, animals and environmental safety. Metal ferrites (AFe2O3, where A is a metal) based sensors are paramount in this field of sensing. Among the gases detectable using metal ferrites includes carbon monoxide (CO), liquefied petroleum gas (LPG), hydrogen sulfide (H2S), petrol and methane (CH4). This reviews presents various parameters which plays key role in the design of ferrite gas sensors. They include; operating temperatures, dopants, grain size, particle size, selectivity, surface area, concentration of the gas, sensitivity as well as recovery time. In addition, the various methods which are used to synthesize ferrite gas sensors are briefly explained. Key considerations in the designing of excellent ferrite gas sensors such as calcination temperature, working temperature, dopants, and concentration as well as optimization condition among others are outlined. In addition this paper reviews the various metal ferrites such as nickel ferrites and nickel doped ferrites, cobalt and cobalt doped ferrites, zinc and zinc doped ferrites, magnesium and magnesium doped ferrites among others that have been researched as gas sensors.