Browsing by Author "Ngari, Mwaniki"
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Publication Analysis of Constituent Chemicals and their Effects on the Physico-Chemical Properties of Spring Water in Ngariama location Gichugu Division Kirinyaga County of Kenya(Journal of Natural Sciences, 2013-08) Ngari, Mwaniki; Wanjau, Tabitha; Njeru, SospeterKeywords: Ground water, Gichugu division has numerous springs, which are a manifestation of potentially high volumes of groundwater. This water is characteristically different from river water in terms of physical parameters like fizzling, characteristic taste and clarity chemistry was studied to explain the above differences. The study established that groundwater in Gichugu area is slightly a (pH 6.49), moderately hard (123.99 mg/l CaCO Cl-). These salts and the pH explained the taste of the water. Also, NaCl and other ionic compounds accounted for the relatively higher conductivity (4.700 Ec µS/cm) while such ions as Ca The percolation of this water through the surface soils of recharge areas generally results in significant purification hence clarity. Fizzling was as a result of dissolved gases such as carbon dioxide and oxygen as they escaped. It was also established that a common groundwater aquifer underlies the area. Iron (0.426 mg/1) and manganese (0.322 mg/1) were found in excess of WHO recommended limits (0.3 mg/1 and 0.1 mg/1 respectively) for potable water quality while fluoride was in relatively low amounts (0.642 mg/1). However, their levels in this water do not make this water unsuitable for drinking since they are still within the acceptable tolerance levels.Publication Environmentally persistent free radicals and particulate emissions from the thermal degradation of Croton megalocarpus biodiesel(Springer, 2018-09-01) Mosonik, Bornes; Kibet, Joshua; Ngari, Mwaniki; Nyamori, VincentPyrolysis of biodiesel at high temperatures may result in the formation of transient and stable free radicals immobilized on particulate emissions. Consequently, free radicals adsorbed on particulates are believed to be precursors for health-related illnesses such as cancer, cardiac arrest, and oxidative stress. This study explores the nature of free radicals and particulate emissions generated when Croton megalocarpus biodiesel is pyrolyzed at 600 °C in an inert environment of flowing nitrogen at a residence time of 0.5 s at 1 atm. The surface morphology of thermal emissions were imaged using a field emission gun scanning electron microscope (FEG SEM) while the radical characteristics were investigated using an electron paramagnetic resonance spectrometer (EPR). A g-value of 2.0024 associated with a narrow ∆Hp-p of 3.65 G was determined. The decay rate constant for the radicals was low (1.86 × 10−8 s−1) while the half-life was long ≈ 431 days. The observed EPR characterization of Croton megalocarpus thermal particulates revealed the existence of free radicals typical of those found in coal. The low g-value and low decay rate constant suggests that the free radicals in particulates are possibly carbon-centered. The mechanistic channel for the formation of croton char from model biodiesel component (9-dodecenoic acid, methyl ester) has been proposed in this study.Publication Physico-Chemical Properties of Spring Water of Gichugu Division, Kenya(LAP LAMBERT Academic , 2013-09-29) Ngari, Mwaniki; Wanjau, TabithaOver the past few years, increased public awareness of environmental issues has caused consumers to be conscious of the quality of drinking water. This is reflected by the large increase of the sales of bottled water and home treatment systems hence the importance of understanding the level of toxicity of the chemical elements/compounds in water. Springs are the major sources of drinking water in Gichugu. Though considered to be pure due to its filtration through layers of soil, spring water has its own health and acceptability problems based on concentration level of certain chemical parameters. Gichugu spring water has unique physical properties. Chemical constituents are thought to have contributed to the altered physical characteristics. This book gives quantitative analysis of some constituent chemicals and other physical parameters. The knowledge goes along way in trying to understand the effects of chemical composition on these physical properties. It is also useful to those concerned with issues of water quality and health, including environmental and public health scientists, water scientists, policy-makers and those responsible for developing standards and regulations.