October 2008
Chemical and surface properties of longan seed activated charcoal
In order to study the chemical compositions and surface properties of longan seed (Daw) activated charcoal, the influences of a phosphoric acid activation process was investigated before and after carbonization. Carbonization temperatures in this study were ranged from 400 - 800°C. It was found that higher carbonization temperatures resulted in a high amount of organic carbon and ashes, while the volatile matters...
October 2008
Effect of kaolin clay addition on mechanical properties of foundry sand moulds bonded with grades 1 and 2 Nigerian acacia species
The research studied effects of addition of kaolin clay on mechanical properties of sand moulds bonded with grades 1 and 2 Nigerian acacia species exudates. The properties included green and dry compressive strength; permeability and hardness; shatter index and the moisture content. Green and dry sand mould specimens bonded with composite mixtures of kaolin clay and each of grades 1 and 2 acacia exudates were subjected...
October 2008
Application of vertical electrical sounding method to decipher the existing subsurface stratification and groundwater occurrence status in a location in Edo North of Nigeria
The interpretation of two resistivity curves over Iyakpi town within geologic terrain often referred to as Ajali formation which bears false-bedded sandstone with associated clay and shale intervals in the bottom section indicates that the area has an abundant groundwater potential. Existence of productive borehole in the study area was field-confirmed. The study area is said to have a standing history of abortive...
October 2008
Thermodynamic properties and relative stability of polybrominated phenoxathiins by density functional theory
The thermodynamic properties of 135 polybrominated phenoxathiins (PBPTs) in the ideal gas state at 298.15 K and 1.013×105 Pa have been calculated at the B3LYP/6-31G* level using Gaussian 03 program. The isodesmic reactions were designed to calculate standard enthalpy of formation (ΔfHÓ©) and standard free energy of formation (ΔfGÓ©) of PBPTs congeners. The relations of these thermodynamic...
October 2008
A class of fixed denominator rational integrators
Existing methods such as Niekerk (1987) and Fatunla (1982) are effective but could not handle problem whose initial value is zero. In this paper, we designed and implemented a class of free denominator rational integrators for the solution of initial value problems (IVPs) in ordinary differential equations (ODES), particularly for the case of Stiff and singular problems. The class of integration obtained was found to be...
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