School of Physical Sciences (SPS)
Permanent URI for this communityhttp://197.211.34.35:4000/handle/123456789/48
School of Physical Sciences (SPS)
Browse
5 results
Search Results
Item Determination of Depth to Buried Magnetic Rocks under the Lower Sokoto Basin, Nigeria Using Aeromagnetic Data. Nigerian Journal of Physics N.J.P. Vol 19 No.2 Pp 275 - 283.(Nigerian Journal of Physics N.J.P., 2007-08) ADETONA, Adebayo Abbass, Udensi E.E. and A.G Agelaga (2007).The Total Aeromagnetic Data covering the study area was subjected to First Vertical Derivative, Spectral Depth Amalysis and Source Parameter Imaging. The result from the First Vertical Derivative shows the Northern part of the area is covered by the young biotite granite of precambrian origin, and the western edge is covered by the old granite, gneisses and migmatite of Western Nigeria, while the remaining area are covered by the cretaceous sedimentary deposits. The entire area was divided into forty eight sections Spectral Depth Analysis was run for each of these forty eight sections, the result shows that a maximum depth above 7 km was obtained within the cretaceous sediments of Idah, and Ankpa, and bellow Udegi at the middle of the study area. Minimum depth estimate between 188.0 to 452 meters were observe around the basement regions. Result from Source Parameter Imaging shows a minimum depth of 76.983 meters and a maximum thickness of sedimentation of 9.847 km, which also occur within Idah, Ankpa and Udegi axis. The disparity observes in depth obtained by each method is discussed base on the merit and demerit of each method, and the depth obtained were compared with result from previous researchers. Geophysical implication of the result to oil and gas exploration in the area is briefly discussed.Item Survey of Gross Alpha and Gross Beta Radioactivity in Sachet water Hawked in Minna, Niger State.(2009) Kolo, M. T.,; Baba-kutugi; OLARINOYE, OYELEKE; Sharifat, I.Item Variations of Surface Radio Refractivity and Radio Refractive Index Gradients in the sub-Sahel(The Nigerian Journal of Space Research, 2009) K. C. Igwe and I. A. AdimulaMonthly variations of radio refractive index near the ground surface have been computed for a period of five years from 2000 to 2004 over Ilorin (8o 32”N, 4o 34”E). The data used was obtained from the University of Ilorin atmospheric observatory operating under the radiometric network of the Baseline Surface Radiation Network (BSRN). Also, seasonal variations of radio refractivity with height of up to 10 km atmospheric layer above ground over Minna (9o 37’’N, 6o 30’’E) have been evaluated. The data used here are those obtained from daily radiosonde ascents made at 1200hrs local time for a period of five years from 1979 to 1983. The refractivity-altitude variation over Minna have been plotted with those of four other low latitude stations and an equation of the form N = NS exp (-0.11h) has also been deduced to predict values of refractivity, N for these stations up to a height, h of about 2 km above ground, for a given surface refractivity, NS. The values of refractive index gradients computed showed that the atmosphere over Minna was subrefractive during the dry season and superrefractive during the wet season periods of the years.Item PATIENT ENTRANCE SKIN DOSES AT MINNA AND IBADAN FOR COMMON DIAGNOSTIC RADIOLOGICAL EXAMINATIONS(BAYERO UNIVERSITY, 2009-06-14) SHARIFAT I; OLARINOYE, OYELEKEEntrance surface dose from two diagnostic x-ray centers in Nigeria for three common radiological examinations is presented in this study. Entrance surface doses for 294 patients drawn from Niger state hospital Minna and Two-Tees x-ray centre, Ibadan are included in this dose survey. The air kerma for each patient was measured using thermoluminescent dosimeter chips (TLD-100). The air kerma for each patient was then multiplied by a back scatter factor of 1.35 to obtain the Entrance surface dose. Generally doses obtained in this study were found to be higher than those in published works and International Atomic Energy Agency recommended limits for chest examination. The range factor at Niger State General Hospital was as high as 12 in some cases but as low as 1 in most cases at Two-Tees X-ray center. The doses obtained for skull and abdomen examination were found to be within acceptable International Atomic Energy Agency recommended limit.Item ESTIMATION OF PATIENTS’ ORGAN DOSES AND CONCEPTUS DOSES FROM SELECTED X-RAY EXAMINATIONS IN TWO NIGERIA X-RAY CENTRES(OXFORD, 2009-01-06) OLARINOYE, OYELEKE; OGUNDARE F,O,Nigeria X-ray centres, Niger State General Hospital (NGH) and Two-Tees (TTX), are reported. Air kerma was measured, and entrance surface dose (ESD) and half-value layer estimated for each set of tube potential (kVp), focus to skin distance and current–time product (mAs) used for each of the patients included in this study. Results show that the mean air kerma in the two centres are similar for the three projections considered in this study. Organ doses ranged from <0.01 to 2.18 mGy in NGH and from <0.01 to 1.29 mGy in TTX for examinations of the abdomen, from <0.01 to 0.20 mGy in NGH and from <0.01 to 0.13 mGy in TTX for examinations of the skull and from <0.01 to 3.90 mGy in NGH and from <0.01 to 1.96 mGy in TTX for examinations of the chest. Generally, no significant difference is seen between the organ doses of male and female patients. In NGH, organ doses are generally greater than those from TTX for the three examinations. The mean ESDs for examinations of the chest postero-anterior, abdomen antero-posterior (AP) and skull AP are, respectively, 5.37, 6.28 and 4.24 mGy in NGH, and 5.82, 5.33 and 4.76 mGy in TTX. The ESDs reported in this study, except for examinations of the chest, are generally lower than comparable values published in the literature. Conceptus doses were also estimated for female patients using normalised published conceptus dose data for abdomen examinations. The estimated conceptus doses were >1 mGyeven when the conceptus was located 12 cm below the surface of the abdomen.