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Item A four-point electrical resistivity method for detecting wood decay and hollows in living trees(Springer, 2019-05) Soge, A. O.; Popoola, O. I.; Adetoyinbo, A. A.An accurate method of detecting wood decay and hollows or cavities in living trees is useful for risk assessment and maintenance of both forest and urban trees. This study presents the implementation of the four-point electrical resistivity method for the early detection of the presence, location and extent of wood decay and hollows in living acacia trees (Senna cilata L.). Electrical resistivity measurement of randomly selected living acacia trees and a freshly-cut acacia tree with decay and hollows were taken to obtain electrical resistivity profiles for sound, decayed and hollowed trees. A laboratory experiment was set up to replicate the resistivity profiles. Wood decay and hollows were replicated at different depths in the laboratory prototype using good electrical conductors and insulators respectively. Resistivity profiles for the sound, decayed and hollowed trees were obtained from the experimental and field results. The resistivity profiles were applied to detect decay and hollows of similar dimensions in living trees through resistivity curve matching. The electrical resistivity of the decayed acacia tree was markedly lowered by an average factor of 5 compared to that of the sound acacia tree. Likewise, the electrical resistivity of the hollowed acacia tree was noticeably greater than that of the sound acacia tree by an average factor of 4. Wood decay and hollows modelled into the laboratory prototype were detected with relatively lower and higher resistivity anomalies respectively. The method indicated that 80% of the randomly selected living trees were sound, healthy trees, whilst 20% had decay and hollow at the time of measurements. This method is suitable for early detection of decay and hollows in hardwood trees.Item Peak particlevelocitydataacquisitionfor monitoring blast induced earth quakes in quarry sites(Elsevier Inc., 2018) Hammed, O. S.; Popoola, O. I.; Adetoyinbo, A. A.; Awoyemi, M. O.; Adagunodo, T. A.; Olubosede, O.; Bello, A. K.The peak particle velocity datasets recorded during quarry blasts in the neighborhood villages and towns in Ibadan and Abeokuta were processed and analyzed in order to recommend a safe blast design for each of the quarries. The minimum peak particle velo- city of 48.27 mm/s was recorded near the foundation of the nearest residence at the shot to monitored distance of 500m. The ten- dency of ground vibration emanating from the quarry sites to cause damage to the structures in the nearby dwelling areas is very high. The peak particle velocity datasets recorded were not within the safe limit. Therefore, the peak particle velocity that will not exceed 35 mm/s is recommended for a safe blast designItem Focal depth, magnitude, and frequency distribution of earthquakes along oceanic trenches(Springer, 2013) Hammed, O. S.; Popoola, O. I.; Adetoyinbo, A. A.; Awoyemi, M. O.; Badmus, G. O.The occurrence of earthquakes in oceanic trenches can pose a tsunami threat to lives and properties in active seismic zones. Therefore, the knowledge of focal depth, magnitude, and time distribution of earthquakes along the trenches is needed to investigate the future occurrence of earthquakes in the zones. The oceanic trenches studied, were located from the seismicity map on: latitude +51˚ to +53˚ and longitude -160˚ to 176˚ (Aleutian Trench), latitude +40˚ to +53˚ and longitude +148˚ to +165˚ (Japan Trench), and latitude -75˚ to -64˚ and longitude –15˚ to +30˚ (Peru–Chile Trench). The following features of seismic events were considered: magnitude distribution, focal depth distribution, and time distribution of earthquake. The results obtained in each trench revealed that the earthquakes increased with time in all the regions. This implies that the lithospheric layer is becoming more unstable. Thus, tectonic stress accumulation is increasing with time. The rate of increase in earthquakes at the Peru–Chile Trench is higher than that of the Japan Trench and the Aleutian Trench. This implies that the convergence of lithospheric plates is higher in the Peru–Chile Trench. Deep earthquakes were observed across all the trenches. The shallow earthquakes were more prominent than intermediate and deep earthquakes in all the trenches. The seismic events in the trenches are mostly of magnitude range 3.0–4.9. This magnitude range may indicate the genesis of mild to moderate tsunamis in the trench zone in near future once sufficient slip would occur with displacement of water column.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 Geophysical investigation of effect of Aba-Eku public refuse dump site in Ibadan (South-West Nigeria) on groundwater quality.(Nigerian Association of Mathematical Physics, 2011) Popoola, O. I.; Adegoke, J. A.; Fakunle, M. A.Geophysical method was used to investigate the effect of Aba-Eku(N 07° 19.551 E 003° 59.027') public refuse dump site in Ibadan on groundwater quality. "Four vertical electrical sounding (YES) data from the vicinity of the dump site and one YES from the control point were acquired using Schlumberger electrode configuration which were subsequently processed and interpreted bazed on the assess of the iteralive computer model using a finite difference algorithm. The result showed that all the sides of the dump site have low resistivity values (side A, p= 22.3Ὠm; side B, p=31.8 Ὠm; side C, p=38.9Ὠm and side D, p=34.7Ὠm) compared with the resistivity value of the control point (Glory Tower Schools, p=60.6Ὠm). The low resistivity values around the ump site is an indication of groundwater pollution. This was confirmed by the laboratory water sample analysis from the vicinity of the damp site.Item Investigation of groundwater development in four areas of Ido local government resistivity method(2010) Popoola, O. I.; Adegoke, J. A.; Fakunle, M. A"This study focuses on the use of geo-electrical sounding for groundwater prospecting in four areas namely Ido Motor Park, (N 07° 18' 40.3"", E 003° 50' 29.2"") Elere- Apata '(N 07° 18' 40.3"", E 003° 50' 29.2"") Bakatari (N07° 18'40.3"", E 003'50'29.2'') and Apete Market (N07° 18' 40.3"", E 003°50' 29.2"") in Ido local government area Southwestern Nigeria. Two (2) Vertical electrical soundings (VES) were carried out using Schlumberger configuration at each of the selected area making a total of eight VES in the four selected areas of the local government. The field resistivity data acquired were plotted on bilogarithm paper and preliminary interpretation was carried out using partial curve matching involving two - layer master curves and the appropriate auxiliary chart. The layered models obtained were subjected to computer iteration using WIN RESIST Version 1 .O. The results of the sounding reveal a system of three to four geo-.electric layers of resistivity ranging from 126.7Ὠm to141 8.8Ὠm Deeply weathered material is quite evident within the premises: Groundwater development in the study area would be feasible if the deeply weathered / fractured basement is fully penetrated. "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. "Item Modification of fluid flow equation in saturated porous media(Bachudo Science Ltd, 2009) Alabi, O. O.; Popoola, O. I.; Adegoke, J. A.Experimental investigations have shown that variation of porosity and hydraulic gradient are responsible for the deviations from Darcy's law, which is perfectly obeyed only when the fluid flow is laminar in porous media. Previous attempts to modify this equation considered only the effects of porosity of surface-active materials such as clay in causing deviations from Darcy's law. In this study, both the effect of porosity of any porous medium and hydraulic gradient from recent experimental data were considered. A general equation for both laminar and non-laminar or turbulent fluid flow in porous media at any hydraulic gradient is proposed, including the boundary conditions.Item Radiogenic heat production distribution of soil samples from Idi Omo, Akinyele LGA, Oyo State, Nigeria(Creative Commons Attribution, 2009) Adegoke, J. A.; Layade, G. O.; Popoola, O. I.The NaI(TI) gamma-ray spectrometer was employed to determine the concentration of naturally occurring Potassium(K-40). Uraniurn (U-238) and Thorium (Th-232) vis-à-vis the radiogenic heat production in soil samples from Idi-Omo farmland area of Akinyele, Local Government area o f Oyo state. The farmland which is at Latitude 07° 30’ 26.3" and Longitude 003° 57' 21.9" covers an area of about 80,000 square metre, and is at an average elevation of 240m above mean sea level (msl). The samples were pulverized, sealed and activities of the radiogenic isotopes in them were measured for an accumulating period of 7 hours (25200s). The elemental concentrations were determined from the gamma ray spectra. The radiogenic heat determined from activity concentrations on samples from the locality for 40k has on the average 92.86±0.02p W/Kg, while 238U has 251.26±0.61pW /Kg and 232Th has 77.210±0.03pW/Kg. The mean radiogenic heat calculated from the three radionuclides for the whole area under study is 421.3.3±0.66pW/Kg. 238U contributes 60% to the total heat production, 40K contributes 22% and 232Th contributes 18%. This makes Uranium to be the highest contributor to the total heat production in the area. However observed that the radiogenic heat production distribution in the area is low.Item Study of permeability of saturated homogeneous and heterogeneous porous media(Duncan Science Company, 2008) Popoola, O. I.; Adegoke, J. A.; Alabi, O. O.Many practical seepage and drainage problems can be studied by constructing flow nets for section with a single permeability, however, many natural soil deposits are more or less stratified, often with horizontal bedding that make horizontal permeabilities much greater than the vertical. Three different types of heterogeneous media from five soil sample of different porosities were considered: with constant-head permeameter to determine the saturated hydraulic conductivity for each. The result shows that least permeable medium dominates in the permeability of heterogeneous medium than layered heterogenous medium. However, fluid flow in homogeneous porous media is generally faster than that of heterogeneous medium of similar geometry and grains packing. Therefore, the effect of least permeable unit in heterogeneous medium must be considered in selecting a proper filter for seepage control.