Physics
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Item Detection of seismic ULF geo-electrical potential variations as tremor precursors prior to quarry blasts(2009-05) Adetoyinbo, A. A.; Popoola, O. l.; Hammed, O. S.; Sumonu, L. A.A seismic ultra low frequency geo-electrical signal recording instrument was set up in three different quarry sites in the south-western part of Nigeria. This research was embarked upon to detect geo- seismic electrical signals produced from the brittle upper crust during rock loading and fracture as a simulated earthquake precursor. The seismic electromagnetic signals emitting from the interior earth in analogical pattern and detected at the earth surface through the signal detectors were transmitted to a conditioning circuit which not only protected the recording instruments from transients caused by ionospheric disturbances but also attenuated the 50 or 60 Hertz frequency caused by high voltage power transmission lines. The spectral analysis of the ULF signals with sampling of 48 KHz recorded during rock loading and fracture in each of the stations revealed that the amplitudes of the signals decrease with increasing frequency. The geo-electrical potential signals associated with ULF waves were varying during deformation stages of crustal layers of rocks. These signals were recorded a few seconds before and after fracture of the rocks as systematic precursors to the main tremors observed in each of the stations and felt five (5) kilometers away.Item Assessment of groundwater quality in unconsolidated sedimentary coastal aquifer in Lagos State, Nigeria(Academic Journals, 2009-04) Adebo, B. A; Adetoyinbo, A. A.This study assesses the quality of ground water from nine different borehole locations in Lagos State, Nigeria. Borehole water samples were carefully collected for physico - chemical analyses. Calcium, magnesium, iron, zinc, copper, manganese, aluminium, and silver, Nitrate, phosphate, fluoride, chloride, pH, conductivity, total dissolved solid, total suspended solid, hardness, summation of ions as well as the temperature and colour were assessed among the entire samples collected. The results show that: temperature ranges from 26.6 - 27.8°C, pH (7.27), average conductivity (462.2 ps/cm), TDS (204.73 mg/l), Total hardness (18.48 - 297.70 mg/l) and Chloride concentration (343.3 mg/l). However, a high value of chloride, 343.3 mg/l, was recorded in one of the water sample collected but, this is higher and above the limit of WHO guidelines of portable water (250 mg/i). This may be due to the proximity of the area where the sample was collected to the sea. Five samples of the water are is soft, that is, hardness was within a range of 0 - 75 mg/l recommended for safe drinking water, one is moderately hard while three samples are hard. Also, the presence of metals such as zinc, manganese, sodium, copper and magnesium were also observed. Results show that not all the water samples are safe for drinking purposes.Item An algoritm for solving electromagnetic field equations by finite element method(Medwell Journals, 2007) Adetoyinbo, A. A.; Adewole, O. O.Describing the behaviour of electromagnetic frequency responses from vertically inhomogenous and anisotropic earth of 2-Dimensional structures energized finite sources is computationally laborious. Differential equations were derived and their numerical solutions also sought for the desired components of electric and magnetic fields. Also, expressions for the impedance and apparent conductivity were stated. An algorithm based on the finite element method for computing approximate numerical solutions for these problems were dealinated.Item Natural radioactivity and hazard assessment of imported ceramic tiles in Nigeria(2009) Ademola, J. A.The natural radionuclides (226Ra, 232Th and 40K) content of ceramic wall and floor tiles commonly used in Nigeria have been determined by a gamma ray spectroscopy system using a high purity germanium detector. The activity concentrations of 226Ra, 232Th and 40K ranged from 52 ± 2 to 105 ± 3, 56 ± 1 to 115 ± 2 and 185 ± 9 to 893 ± 17 Bq kg-1 with mean values of 72 ± 14, 84 ± 18 and 629 ± 198 Bq kg-1, respectively for the wall tiles. For the floor tiles, the activity concentrations of 226Ra, 232Th and 40K varied from 41 ± 2 to 131 ± 4, 59 ± 1 to 127 ± 2 and 351 ± 11 to 979 ± 16 Bq kg-1 with mean values of 74 ± 31, 82 ± 24 and 618 ± 231 Bq kg-1, respectively. The errors quoted in the means are standard deviations. The values of radium equivalent activity (Raeq) calculated varied from 194 to 328 Bq kg-1 for the wall tiles, and 176 to 306 Bq kg-1 for the floor tiles. The radium equivalent activities of all the samples examined were lower than the recommended limit of 370 Bq kg-1 for building materials. The mean values of the external hazard index (Hex), the activity index (Iγ) and the alpha index (Iα) of the wall and floor tiles are less than unity, which is a commonly accepted limit.Item The effects of porosity and angels of inclination on the deflection of fluid flow in porous media(Medwell Journals, 2009) Popoola, O. I.; Adegoke, J. A.; Alabi, O. O."The movement of contaminated fluid from a solid waste landfill into a portable water aquifer located beneath is an example of unwanted underground flow. With the problem of limited portion of land available for building construction in the cities, coupled with the rise in price of good and accessible land, there is a need for quick and urgent solutions to environmental pollution that may be resulted from this problem. In this research, a laboratory setup consisting of a big transparent cylindrical pipe 108.5cm long with radius 2.23cm was used as inlet pipe and five small equal transparent cylindrical pipes with radii 0.03cm were used as outlets, which were joined to the circular plastic plate on the top of the inlet pipe at different angles ranged from 00 to 900 from a normal point. The inlet pipe and outlets pipes were filled with samples of soil of different porosities and titled at different angles of inclination. The volume of water discharged was measured directly with measuring cylinder from the set-up in each case. The volumetric flow rate and volume flux were computed from the values of volume discharged. These were done in order to determine how the arrangement of porous material of different porosities with a particular angle of inclination can influence the deflection of fluid flow from its linear direction. This is sequel to its practical applications in designing a construction with a cross-section of soils in deflecting contaminated fluid from septic tank to different directions from the source of water within the same small portion of land. It was observed that angle of inclination does not have a significant effect on the deflection of fluid but volume flux increases with increasing angle of inclination. Also, the greater the difference in the porosity of the cross-section of the media in which the fluid is flowing the greater the volume flux. However, the most suitable arrangement of cross-section of soils for deflection of fluid at higher angle from normal is when it flows through a medium of low porosity to that of higher porosity. "Item Monitoring the effect of water pollution in twelve selected water dams in Osun State of SouthWestern Nigeria(2007) Adegoke, J. A.; Sunmonu, L. A.; Lateef, T. A."The level of water pollution by heavy metals (Cu, Zn,Co, Ni, As, Mn, Cd, Cr, Pb) in twelve selected water Dams in Osun state were determined in order to know their distribution and possible source into the dams. Their bottom sediment and water were collected for analysis. The result in sediment showed that the concentration of manganese is high in all the dams with values ranging from 21, 27-775.99mg/kg and it spreads across all the locations. Cobalt was detected only at one location with concentration of 3.01md/kg. The result in water analysis showed that the concentration of zinc is more than that of manganese, almost in all the dams. The values detected were between 0.0618lng/kg and 0.5068mg/kg while that of manganese was between 0.011 2mg/kg and 0.1887 mg/kg. Cobalt and cadmium were not detected in all the dams. The variation in the concentration of these metals in sediment and water may be due to chemical factors such as solubility, ion exchange ratio and electrochemical deposition. The concentrations of all metals detected were below the standard limit for the heavy metals in surface water according to Regulatory authority Specification. Meanwhile, bioaccumulation of these metals in tissue of the body may be toxic to human health. "Item Evaluation of heavy metal status of water and soil at Ikogosi warm spring, Ondo State Nigeria(Department of Geography and Enivironmental Studies and Management, Bahir Dar University, Ethiopia, 2009) Adegoke, J. A.; Agbaje, W. B.; Isaac, O. O.The concentration levels of selected heavy metals, (Cu, Cd, Zn, As and Cr) were determined in the soil (ug/g) and water (ppm) samples collected at Ikogosi Warm Spring, Ekiti State, Nigeria. After digestion, Atomic Absorption Spectrophotometer (AAS) was employed for the determination. The study area was at Latitude of 7° 35' 38.9'' Longitude of 4° 58' 52.6'' and at average elevation of 479m above mean sea level (msl). The average concentrations (ug/g) of the heavy metals in the soil are Cu (5.29), Cd (1.50), Zn (46.72), As (10.50) and Cr (339.78). The average concentrations (ppm) of the heavy metals in the water are Cu (4.8), Cd (0.15), Zn (4.17), Ar (0.57) and Cr (1.46). The mercury was below detection limit for both soil and water samples. In the overall, the average concentration of chromium is the highest in the soil with concentration of 339.78 ug/g (an average of 84.27%) and cadmium having the lowest with value of 1.50 ug/g (an average of 0.37%). When average concentration of heavy metal in the water was considered, copper had the highest level with concentration of 4.80ppm (an average of 43.01%) and cadmium had the lowest concentration with value of 0.15ppm (an average of 1.43%). Comparison of these results showed that, their mean levels are within the standard values obtained in Nigeria and some developed countries.Item Open land dumping: an analysis of heavy metals concentration of an old Lead-battery dumpsite(2009) Adegoke, J. A.; Owoyokun, T. O.; Amore, I. O."Use of open land as dump sites by the manufacturing industries in developing countries without appropriate prevention of environmental hazards has resulted in prominent levels of waste and disposal effluents. This has resulted in the contamination of soil and the exposure of human populations to environmental and health hazards. This study focused on the investigation of soil contamination by heavy metals via waste disposal of a lead battery factory in Lalupon, Oyo State, Nigeria. Composite samples obtained from nine sample locations were digested with concentrated acids (HN03, HC104 and HF) and filtered. The filtrate obtained was analyzed for seven different analytes (Cu, Cr, Pb, Zn, Cd, Ni, and As) using atomic absorption spectroscopy (AAS). The lead content exceeded maximum allowable concentrations, MAC (100 ppm), in all points. Copper content was above MAC (50 ppm) in a majority of the points. Cd exceeded MAC (0.3 ppm) in just one point. The study shows that the soil in the old dump site has been contaminated heavily with Pb and Cu. "Item Determination of transition length in flow through porous sand material(2009) Adegoke, J. A.; Olowofela, J. A.A transition length is normally observed when fluid flows through a conduit before laminar flow is accomplished. This work examined a situation whereby porous materials were filled into the conduit and fluid was made to flow through. An attempt was made to determine this transition length for flow of water through riverbed sand of varying porosities filled into a horizontal cylindrical pipe of diameter 0.345 x 102m with piezometric water head, set at 0.06m. The transition length was observed to be constant for the samples considered and it occurred at 0.60m from the point of entrance; nevertheless, values of pressure at this point increases with increase in porosity.Item The effects of porosity and angle of inclination on the deflection of fluid flow in porous media(Bachudo Science Ltd, 2009) Popoola, O. I.; Adegoke, J. A.; Alabi, O. O."The movement of contaminated fluid from a solid waste landfill into a portable water aquifer located beneath is an example of unwanted underground flow with the problem of limited portion of land available for building construction in the cities, coupled with the rise in price of good and accessible land, there is a need for quick and urgent solutions to environmental pollution that may be resulted from this problem. In this research, a laboratory setup consisting of a big transparent cylindrical pipe 108 5cm long with radius 2 23cm was used as inlet pipe and five small equal transparent cylindrical pipes with radii 0.03cm were used as outlets, which were joined to the circular plastic plate on the top of the inlet pipe at different angles ranged from 0° to 90° from a normal point. The inlet pipe and outlets pipes were filled with samples of soil of different porosities and titled at different angles of inclination. The volume of water discharged was measured directly with measuring cylinder from the set-up in each case. The volumetric flow rate and volume flux were computed from the values of volume discharged. These were done in order to determine how the arrangement of porous material of different porosities with a particular angle of inclination can influence the deflection of fluid flow from its linear direction. This is sequel to its practical applications in designing a construction with a cross-section of soils in deflecting contaminated fluid from septic tank to different directions from the source of water within the same small portion of land. It was observed that angle of inclination does not have a significant effect on the deflection of fluid but volume flux increases with increasing angle of inclination. Also, the greater the difference in the porosity of the cross-section of the media in which the fluid is flowing the greater the volume flux However, the most suitable arrangement of cross-section of soils for deflection of fluid at higher angle from normal is when it flows through a medium of low porosity to that of higher porosity. "
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