

Articles
by
O.O. Alabi 
Total Records (
4 ) for
O.O. Alabi 





R.A. Adenodi
,
O.O. Alabi
,
B.F. Akinwale
and
F.O. Akinluyi


The necessary d. c. supply for electronics instrument may be drawn from batteries. However, the e.m.f. of batteries is not usually constant throughout life and also there is the danger of leakage which may endanger both the electronic circuit and the users. Power supply is a constant d.c voltage source suitable for operating electronic instruments without the danger associated with batteries. The 14pin DIL (µA723A) version of voltage regulator IC was incorporated to continuously monitors the d.c voltage output and automatically holds it constant irrespective of changes in the load current and unregulated input voltage. A divided fraction of the output voltage is compared with a fraction of the stable voltage reference to give a current of 150mA, which is boasted to 500 mA by an external transistor. The unit has excellent stability. 





O.O. Alabi
,
Kayode Ayinde
and
B.A. Oyejola


The effect of multicollinearity on the parameters of regression model using the Ordinary Least Squares (OLS) estimator is not only on estimation but also on inference. Large standard errors of the regression coefficients result in very low values of the tstatistic. Consequently, this study attempts to investigate empirically the effect of multicollinearity on the type 1 error rates of the OLS estimator. A regression model with constant term ( _{0}) and two independent variables (with _{1} and _{2} as their respective regression coefficients) that exhibit multicollinearity was considered. A Monte Carlo study of 1000 trials was conducted at 8 levels of multicollinearity (0, 0.25, 0.5, 0.7, 0.75, 0.8, 0.9 and 0.99) and sample sizes (10, 20, 40, 80, 100, 150, 250 and 500). At each specification, the true regression coefficients were set at unity. Results show that multicollinearity effect on the OLS estimator is not serious in that the type 1 error rates of _{0} is not significantly different from the preselected level of significance (0.05), in all the levels of multicollinearity and samples sizes and that that of _{1} and _{2} only exhibits significant difference from 0.05 in very few levels of multicollinearity and sample sizes. Even at these levels the significant level different from 0.06. 





R.T. Akinnubi
,
B.F. Akinwale
,
M.O. Ojo
,
P.O. Ijila
and
O.O. Alabi


Characteristic variation of relative humidity and solar radiation enhances the understanding of the significance of indicated trends of variability to everyday life and the factors that might be responsible for such variations. This study critically analyses the seasonal trends and the existing relationship between solar radiation and relative humidity of Ibadan, Nigeria. The data used for the study were extracted from a 48 months (19992001) daily radiation data estimated from GunnBellani distillate and relative humidity obtained from International Institute for Tropical Agriculture (IITA) Ibadan (7.3°N, 3.3°E), Oyo State. Simple graphical methods were adopted to analyze the trends of variation, using average monthly values for each parameter. The monsoon depression usually occurs annually during the month of August. The minimum value of solar radiation and a high value of relative humidity of 10.3MJ/m^{2}/day and 87.8%, respectively were recorded during this month. The curves on the mean relative humidity are inversely proportional to observed curves on solar radiations. 




O.O. Alabi
and
O.O. Adewole


Survey for radiometric minerals has become important over the last few decades because of the demand for alternative to present common source of energy. Radiometric survey is one of the geophysical techniques in use in exploration for geothermal energy, which is generated mainly from the decay of longlived radioactive isotopes. Ten fresh rock samples were collected from OsunOsogbo river. This is to determine their radioactive heat production and the contribution of each radionuclide content. The radiogenic heat production was determined in the laboratory using NaI(Tl) gammaray spectrometer. The results shows that the contribution and rate of heat production of ^{40}K, ^{238}U and ^{232}Th in the samples vary significantly with lithology. (rock type) and rock samples OS4 (mica) is associated with high heat production uranium. 





