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Effect of Variable Viscosity, Dufour, Soret and Thermal Conductivity on Free Convective Heat and Mass Transfer of Non-Darcian Flow past Porous Flat Surface  [PDF]
Isaac L. Animasaun, Anselm O. Oyem
American Journal of Computational Mathematics (AJCM) , 2014, DOI: 10.4236/ajcm.2014.44030
Abstract: The motion of incompressible fluid of a variable fluid viscosity and variable thermal conductivity with thermal radiation, Dufour, Soret with heat and mass transfer over a linearly moving porous vertical semi-infinite plate with suction is investigated. The governing equations are transformed into a system of coupled nonlinear ordinary differential equations using similarity transformations with dimensionless variables and solved numerically using shooting method with Runge-Kutta fourth-order method and Newton-Raphson’s interpolation scheme implemented in MATLAB. The result showed that with increase in Dufour and Soret parameter, fluid velocity increases and temperature increases with increase in variation of Dufour while, temperature decreases with increase in Soret. The effects of variable fluid viscosity, variable thermal conductivity, thermal radiation, Soret, Dufour, Prandtl and Schmidt parameters on the dimensionless velocity, temperature and concentration profiles are shown graphically.
Analysis of the Atmospheric Aerosol Loading over Nigeria
A.A. Oyem,A.I. Igbafe
Environmental Research Journal , 2012, DOI: 10.3923/erj.2010.145.156
Abstract: This study, which was established with published data between March 2007 and February 2008 utilised the number of aerosol optical thickness recorded using satellite imageries. Backward air mass trajectories by means of the HYSPLIT simulation model was used to evaluate the aerosol transport patterns. It was deduced that precipitation, wind speed and relative humidity alters the level of aerosol loadings at different times of the year yielding an inverse relationship between these properties. Aerosols also alter temperature resulting to a direct relationship between both properties. In addition, the meteorology of the lower troposphere has been identified to be fully responsible for both local air pollutions and long-range aerosols transport.
Analysis of the Atmospheric Aerosol Loading over Nigeria
A.A. Oyem,A.I. Igbafe Air Pollution Climatology,Energy Research Group
Environmental Research Journal , 2012, DOI: 10.3923/erj.2010.204.211
Abstract: This study, which was established with published data between March 2007 and February 2008 utilized the number of aerosol optical thickness recorded using satellite imageries. Backward air mass trajectories by means of the HYSPLIT simulation model was used to evaluate the aerosol transport patterns. It was deduced that precipitation, wind speed and relative humidity alters the level of aerosol loadings at different times of the year yielding an inverse relationship between these properties. Aerosols also alter temperature resulting to a direct relationship between both properties. In addition, the meteorology of the lower troposphere has been identified to be fully responsible for both local air pollutions and long-range aerosols transport.
Monitoring the Free Fatty Acid Level of Crude Palm Oil Stored under Light of Different Wavelenghts
Oyem H. Henry
American Journal of Food Technology , 2011,
Abstract: The effect of light of different colours (wavelength) on the Free Fatty Acid (FFA) value of stored crude palm oil is hereby reported. Equal portions of the palm oil samples were stored in an environment of red, blue and green lights, respectively for a period of 21 days. Aliquots were taken from each of these samples at two days interval for analysis. And the FFA values obtained plotted against the number of days of storage. Results obtained indicate that the FFA values of the oil increased with storage time. Also and more revealing is the fact that the FFA values of the samples did not follow any established order, especially as related to the spectrum of light.
Analysis of Nigeria Power Generation Sustainability through Natural Gas Supply
Oyem, Isama Lawrence
Journal of Innovative Research in Engineering and Sciences , 2013,
Abstract: The use of natural gas as a fuel in heat engines for the generation of electricity is a technology that has been for decades, which operates on the Brayton cycle principle. In a bid to meet the energy needs of Nigerians despite its unparallel gas potentials of about 187 TCF of proven gas reserves, Ughelli Power PLC was put under study. The study reveals that there was an uneven energy generation despite the large quantity of gas supplied. Nigeria’s total installed capacity is at 6000 MW with its present output at 3000MW. The study of Delta four power plants reveals an average consumption of 1,021,490,501.43 scf of gas indicating 82,461.24 MWH (178.1MW) energy generation. A total average power generation of 30.5% out of the installed capacity was found, resulting in 2.9% of National contribution. It is strongly recommended that Proper gas conservation practices should be enforced.
Barium, Calcium and Sodium, Cyanide, Phosphate and Sulphate Contents of Groundwater in Some Ika Communities of Delta State, Nigeria  [PDF]
Hector H. Oyem, Ifeanyi M. Oyem, Esther N. Obiwulu
Journal of Geoscience and Environment Protection (GEP) , 2017, DOI: 10.4236/gep.2017.58009
Abstract: Barium, calcium, sodium, cyanide, phosphate and sulphate and contents of groundwater in Boji-Boji (BB) area and suburbs of Ika land, Delta State, Nigeria were studied. Groundwater is the predominant source of water for inhabitants of these communities without any form of treatment. 55 borehole water sites spread within these five sample sub-areas. The metal ions were analyzed using Solar Unicam flame Atomic Absorption Spectrophotometer. Sulphate, phosphate, and cyanide contents were determined by colorimetric method. Results indicate the presence of sodium, calcium, sulphate, and phosphate. However, barium and cyanide were below detection limit. Secondly, there was a relatively higher proportion of calcium and sulphate than sodium and phosphate in its aquifer. Thirdly, a mean ratio value of 0.018 and 0.158 was observed for the ratios of Na+/Ca2+ and \"\"?respectively. Fourthly, sodium showed good correlation with all the other parameters. Finally, nearly all the studied parameters have concentrations below the maximum contaminant levels of the World Health Organization (WHO), invariably inferring that the water is wholesome with respect to the analytes. However, concern still remains from a health point of view on the sodium concentrations in many sample areas.
On the Analysis of Variable Thermophysical Properties of Thermophoretic Viscoelastic Fluid Flow past a Vertical Surface with nth Order of Chemical Reaction  [PDF]
Olubode Kolade Koriko, Tosin Oreyeni, Onyekachukwu Anselm Oyem
Open Access Library Journal (OALib Journal) , 2018, DOI: 10.4236/oalib.1104271
Abstract:
The objective of this study is to consider the flow of temperature dependent viscosity and thermal conductivity of free convective heat and mass transfer of viscoelastic fluid over a stretching surface with nth order of chemical reaction and thermophoresis. The effect of the temperature dependent dynamic viscosity and thermal conductivity together with modified thermal and solutal Grashof numbers are properly accounted for in order to enhance the transport phenomenon. Similarity transformations are used to convert and parameterize the non-linear partial differential equation to a system of coupled non-linear ordinary differential equation. The approximate analytical solutions of the corresponding BVP are obtained through Optimal Homotopy Analysis Method (OHAM). The effect of some pertinent parameters is tested on velocity, temperature, concentration profiles. It is observed from the computation that, the thickness of the velocity and thermal boundary layer increases with an increase in temperature dependent variable viscosity and thermal conductivity parameters when modified thermal and solutal Grashof numbers and are less than zero. It is also observed that the concentration layer becomes thinner with increasing thermophoresis parameter when the chemical reaction parameter is greater than zero for both cases of first and second order of chemical reaction i.e. when n=1,2.
Finite Element Analysis of Von-Mises Stress Distribution in a Spherical Shell of Liquified Natural Gas (Lng) Pressure Vessels  [PDF]
O. A. Adeyefa, O. O. Oluwole
Engineering (ENG) , 2011, DOI: 10.4236/eng.2011.310125
Abstract: This research work investigated the modeling of Von Mises stress in LNG Spherical Carbon Steel Storage tank using assumed displacement Finite Element analysis based on shallow shell triangular elements. Using equations of elasticity, constant thickness carbon steel spherical storage tanks were subjected to different loading conditions. This paper stresses the need for proper definition of shallow element using sector angles to obtain the shallowness. The shallow spherical triangular element has five degrees of freedom at each of its corner node, which are the essential external degrees of freedom. The assumed displacement fields of these shallow triangular elements satisfied the exact requirement of rigid body modes of motion. The FORTRAN 90 programming language was used for the programme coding to solve finite element equations resulting from the model while Von Mises stresses distribution within the spherical storage tank shell subjected to different internal pressures were determined. The results showed that the use of non-shallow elements due to improper sector angles resulted in unreliable results while real shallow elements produced results that tallied with ASME Section VIII Div 1, Part UG values.
Comparative Study of the Effect of Temperature on the Corrosion Behaviour of 2205 Duplex Stainless Steel and 316 Austenitic Stainless Steel in Acidic Chloride Environment  [PDF]
O. A. Olaseinde
Advances in Materials Physics and Chemistry (AMPC) , 2015, DOI: 10.4236/ampc.2015.55019
Abstract: The 2205 duplex stainless steel and 316 austenitic stainless steels were studied in 1 M sulphuric acid and 1% NaCl solution. The microstructures of the specimens were investigated with scanning electron microscopy with energy dispersive X-ray analysis. X-ray Diffraction analysis was used for phase analysis. The electrochemical behaviour was evaluated using potentiodynamic method. The results show that the critical current density is higher for 316 austenitic stainless steels than 2205. The passive range was longer for 316 than 2205 at all the temperatures understudy. 2205 was found to have better corrosion resistance than 316.
Using the Dual Energy Gamma-Ray Transmission Technique to Measure Soil Bulk Density and Water Content of Central Southwestern Nigerian Soils  [PDF]
O. O. Adejumo, F. A. Balogun
Journal of Environmental Protection (JEP) , 2012, DOI: 10.4236/jep.2012.311160
Abstract: In this work, a radiological technique which simultaneously measures soil bulk density and water contents accurately and quickly in a non-destructive manner at different depths of the soil profile of the major soil series of Central Southwestern Nigeria is developed. Undisturbed samples from Iwo, Ondo, Egbeda, Itagunmodi, Okemessi, Mamu, Origo and Jago soil series of Southwestern Nigeria were collected on monthly intervals from June 2006 to May 2007. Using gamma-ray energy pairs of 122 and 1112 keV; and 344 and 1408 keV obtained from europium-152 (152Eu) radionuclide, the attenuation coefficients for soil and water, μs, μw and consequently ρs and θv at varying soil depths of these series were calculated. Comparative gravimetric measurements of these soil parameters were carried out. Using the XCOM computer algorithm with the soil elemental concentrations obtained using the Energy Dispersive X-Ray Fluorescence analysis (EDXRF) technique, theoretical estimates of μs for the various soil series were obtained and compared with the experimental values. The result of the developed dual energy gamma-ray transmission technique was compared with the gravimetric measurement method and Pearson correlation coefficient (0.987, p < 0.001) was obtained for ρs and (0.996, p < 0.001) for θv. The results of the measurements showed that θv minima with values 0.1931, 0.1987, 0.2377, 0.2111, 0.1738, 0.1701, 0.2334, 0.2341 and minima ρs values of 1.21 g/cm3, 1.20 g/cm3, 1.02 g/cm3, 1.38 g/cm3, 1.12 g/cm3, 1.14 g/cm3, 0.64 g/cm3, 1.33 g/cm3 were obtained respectively for the soil series stated above in January. The maxima θv with values 0.3621, 0.4212, 0.3962, 0.3794, 0.3049, 0.2811, 0.4415, 0.4416 and maxima ρs values of 1.52 g/cm3, 1.67 g/cm3, 1.74 g/cm3, 1.69 g/cm3, 1.70 g/cm3, 1.68 g/cm3, 1.08 g/cm3, 1.54 g/cm3 occurred for these soil series respectively in July except for Mamu soil series which occurred in May. These correlated very well with the occurrence of the Dry and Rainy seasons in the study area. The results of the EDXRF analysis showed that maxima Iron, Fe concentrations of 5.0890 ppm at the depth of 90 - 120 cm into the soil profile, was obtained for Iwo series, 4.4691 ppm at 50 - 70 cm for Ondo, 6.3438 ppm at 15 -
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