Browsing by Author "Lawal, T. O."

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    INTERPRETATION OF HIGH RESOLUTION AEROMAGNETIC DATA OVER PART OF NORTHWESTERN, NIGERIA
    (Federal University Gashua. Yobe State, 2016) Lawal, T. O.; Sunday, J. A.; Nwankwo, L. I,; Ayedun, F; Jolaoso, O. S
    Interpretation of HRAM data over part over part of Northwest Nigeria has been carried out with the aim of delineating lineament structures such as faults, contacts, joints etc. and estimating the depth to the top of the magnetic basement (which is equivalent to the sedimentary thickness). This research work makes use of a Total Magnetic Intensity (TMI) acquired from Nigerian Geological Survey Agency which was part of the recent nationwide airborne magnetic survey carried out in 2010.The map was gridded into eighteen non-overlapping blocks (20 x 20 km) and each of the blocks was analysed using Spectral analysis which reveals two source depths, depth to shallow magnetic sources which ranges from 0.12 km to 0.30 km and depth to deeper magnetic sources which ranges from 0.98 km to 1.81 km. Also, the study area reveals parallel contour lineament trending NE – SW and subordinate E-W direction which are suggestive of fault and joint in the area. The result obtained from the study which reveals the depths to basement structures and delineation of lineament structures would complement the existing geophysical information of the area
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    Natural Radionuclide Concentration and Radiological Impact Assessment of Soil and Water from Dadinkowa Dam, Northeast Nigeria.
    (Journal of the Nigerian Association of Mathematical Physics, 2017-07-16) Orosun, M. M.; Lawal, T. O.; Ezike, S. C.; Salawu, N. B.; Atolagbe, B. M.; Akinyose, F. C.; Ige, S. O.; Oluyide, S. O.; Adebanjo, G. D.; Osanyinlusi, O.; Martins, G.
    Radioactivity measurement of water and sediment samples from Dadinkowa dam, Gombe, Nigeria was carried out using a lead-shielded “76mm×76mm˝ Sodium iodide [NaI(TI)] detector connected to ORTEC 456 amplifier. The obtained gamma resultswere used to estimate some radiological impact parameters in order to effectively ascertain the level of the radiological health hazard to humankind by the use of such materials in the study area. The mean absorbed dose rates for the sediment and water samples were 66.09 and 39.01 nGy h-1, respectively while the mean Annual Effective Dose (AEDE) for the ingested radionuclide in water samples from the area for infants, 1 year, 5 years, 10 years, 15 years and adults were 0.00276, 0.00313, 0.00197, 0.00135, 0.00117, and 0.00187 Sv/y, respectively.The mean AEDEoutdoor for the sediments was 0.0809 mSv/y and mean AEDEindoor was 0.324 mSv/y.Similarly,the mean Radium Equivalent Activity Index (Raeq) for the sediment and water samples was 139.83 Bq kg-1 and 30.84 Bq/L respectively, while the mean estimated internal and external hazard indices for the sediment samples were 0.52 and 0.37, respectively and that of water samples were 0.13 and 0.09, respectively. Furthermore, the estimated mean values for the AGED in the sediment and water were 458.49 and 104.60 μSv/y respectivelywhilethe estimated mean Iγfor the sediment and water samples were 1.030 and 0.229 mSv/y, respectively.Conclusively, the estimated mean the Excess Lifetime Cancer Risk (ELCR) for the sediment sample was 0.280 x 10-3 while that of water samples were 9.66, 10.96, 6.90, 4.73, 4.10 and 6.58 10-3 for 1 year, 5 years, 10 years, 15 years and adults, respectively. The results showed trends that were generally low for most of the radiological impact parameters calculated except for few indices whose values were above the UNSCEAR recommended thresholds. Therefore, there may be no serious immediate radiological effects to the populace and the environment in this area