Browsing by Author "Adetoyinbo, A. A."

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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.
Assessment of building failure within and around quarries
(2019-07) Adetoyinbo, A. A.
The substructures of various engineering structures that were erected on the earth are being were been supported by the soil. Hence, the nature of the soil supporting these structures becomes an important issue. Quarry blasting peak particle velocity (QBPPV) is not sufficient to ascertain the causes of foundation failure, therefore, the physical parameters governing the competency of the soil supporting engineering structures need to be determine. This work investigated the possible causes of foundation failure of buildings within the vicinity of quarries. The investigation was done by carrying out Vertical Electrical Sounding (VES) and Radial Vertical Electrical Sounding (RVES) using Campus omega terrameter. The results show that buildings found within this area have shallow foundation and their foundations founded on sandy clay which can still support foundation The values of the degree of fracturing was found not to exceed 1.53 in this region which was not the case with the previous radial vertical electrical soundings, 1.94 was calculated as the highest degree of fracturing for RVES 1 while 1.83 was calculated for RVES 2. In all the RVES, degree of fracturing ranges between 1.02 to 1.94.
Assessment of ground water pollution in Itagunmodi, South-West, Nigeria
(2012-02) Adetoyinbo, A. A.; Bello, A. K; Hammed, O. S.
Some investigations have been earned out on geochemical characteristics of soil samples that embedded the ore deposits. Physiochemical analysis of water collected within gold mining area and the water consumed in the town of Itagunmodi was earned out to determine their hygienic conditions. The major objective of this study was to determine the suitability of the available water consumed in the town based on the Physiochemical analysis test carried out. In this regards, four major sources of water were analyzed. Analysis shows that the water within the town of Itagunmodi was hygienic with the inclusion of water within the mining site. The analysis includes; conductivity test, the pH test and others. It was noticed that the pH of the sample from the gold mining site was also suitable for drinking according to the World Health Organization standard. For a safe drinking water, the pH should be between (6.5 -8.5).
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.
Depth probing soft x-ray microprobe (dpsxrm) for high resolution probing of earth’s microstructural samples
(2016-06) Dikedi, P. N.; Adetoyinbo, A. A.
The Cambrian explosion: occurrence of landslides in very dry weather conditions: rockslides; dead, shriveled- up and crumbled leaves possessing fossil records with the semblance of well preserved, flat leaves: abundance of trilobite tracks in lower and higher rock layers: and sailing stones are enigmas demanding demystifications. These enigmas could be elucidated when data on soil structure, texture and strength are provided by some device with submicrometre accuracy; for these and other reasons, the design of a Depth Probing Soft X-ray Microprobe (DPSXRM), constituting a rotating X-ray window is being proposed; it is expected to deliver soft X- rays, at spatial resolution, Ω 600nm and to probe at the depth of 0.5m in 17s. Assessing subsurface stratigraphy is possible with the DPSXRM. The microprobe is portable comparedfo a synchrotron radiation facility (Diamond Light Source has land size of 43,300m* 2); spatial resolution,'q > 600nm, of the DPSXRM surpasses those of the X-ray Fluorescence microanalysis(lOpm), electron microprobe (I-3pm), and ion microprobe (5->30pm); the DPSXRM has allowance for multiple targets. Amongst other major optical components, a Fresnel Zone Plate (FZP) and Rotating X-ray Window are incorporated into the design to ensure that the desired image resolution is achievable and that the X-ray window membrane material survives the heat flux importation on it. Reflecting, refracting, diffracting and (or) absorbing optics areddentified as techniques needed to achieve this resolution. Vanadium and Manganese membranes are proposed owing to respective 4.952KeV VKa, and\ 5.899KeV MnKai X-rays emitted, which best suits micro-probing of Earth's microstructural samples. Compound systems like the Kirk-Patrick and Baez, electromagnetic lenses, small apertures and Abbe sine condition are considered to reduce or remove astigmatism and coma and spherical aberrations—leading to good image quality. Results are presented alongside, and relevant graphs are plotted. Magnification values of - 1.5 ≤ M ≤ 1.5, at - 70° ≤ θ ≤ 75° when - 30° ≤ θ ≤ 30° satisfied Abbe Sine Condition. The nth zone radius increases with the distance of separation of the DPSXRM’s electron gun and the zone plate. 5.899KeV MnKat and 4.952KeV VKa soft X-rays will travel a distance of 2. 75mm to form circular patches of radii 2.2mm and 2.95mm respectively. Zone plate with nth zone radius of 1.5mm must be positioned 1.5mm and 2 mm from the electron gun if circular patches must be formed from 4.952KeV VKat and 5.899KeV MnKajSoft X-rays respectively. The focal lengths of 0.25µm < F < 1.50µm and 0.04µm < F < 0.2µm covered by 4.952KeV VKat and\ 5.899KeV Mn Kat soft X-Rays, will occupy circular patch of area 0.03 mm2 < A < 0.2 mm2 respectively. The spatial resolution of 244nm < ς < 1460nm is attainable forfocal lengths of 38.1nm < F < 229nm and 32.0 nm < F < 1460192nm covered by 5.899KeV Mn Ka, and 4.952KeV VKa soft X-rays, respectively. Simulation results from COMSOL Multiphysics software uncover some deformations in Vanadium and Manganese microstructures.
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.
Determination of stress-bulk modulus in the lithosphere and the peak particle velocity with regards to sediment-hosted disseminated gold deposit
(2017-03) Adetoyinbo, A. A.; Bello, A. K.
The tectonic activities happening within the subsurface has led to a huge trapped pressure within the plate boundaries looking for escape through the weakest points to the surface. This has led to deformation in the lithosphere which was greatest at the plate boundaries. In recent time, sediment-hosted disseminated gold deposits had been an important ore mineralization. From research it was suggested that gold, a material from subsurface derived from the core-mantle region passes through different regions of different densities, pressures and temperatures. Bulk modulus, an important parameter determined from the thermodynamic properties was investigated to the depth of the lithosphere. The ground movement was also determined with a view to ascertain the save distance and precautions when handling explosives as tools in underground mining.
Determination of temperature profile of the lithosphere between zero and 150 km penetration at Itagunmodi, Nigeria
(AJOL, 2019-06) Adetoyinbo, A. A.; Bello, A. K.
In this work the temperature profile for the lithosphere was determined using data from radiogenic heat source and heat from other sources from 0 to 150 km depth was determined using a suitable mathematical expression. The temperature at the base of the lithosphere was given between 1200°C to 1600°C. The Fourier’s law was applied and the results showed that the profile range from 27.0°C to 1483.3°C. These results compared favourably well with existing literature values.
Electrical resistivity interpretation method & resistivity profile for investigations on selected case studies
(2017) Adetoyinbo, A. A.; Ewumi, T. A.
Electrical resistivity has been previously reviewed with interpretation of presented earlier in a case study, it is known that resistivity surveys are all based on the method of Wenner. A current, I, is passed into the earth through one point electrode and returns to the apparatus through a second. The potential difference between two points on the earth's surface, V, is measured. The profile based on the ‘VES’ interpretation on an extended review of a previous publication from a landslide filled site adjacent to a dumpsite from Abule- Egba Area and environ in Lagos was presented here.
Employing DC resistivity method for hydrogeological analysis of Zuma II, a VES approach
(2017) Dikedi, P. N.; Sule, A. U.; Adetoyinbo, A. A.
This research work employs the DC Resistivity method for Hydrogeological analysis in Veritas University, Zuma II, Bwari Area Council, Abuja, FCT, Nigeria. The work attempts to tackle the immense water shortage crisis within the University, this work also, attempts to provide access to stratigraphic information and to assist groundwater development for the region. Schlumberger array and electrical sounding technique are adopted for subsurface delineation. Eleven resistivity profile graphs generated from tabled data are presented by employing the Winresist software and Microsoft excel. A The outcome of this investigation revealed four spots with good potentials for ground water; these points are located within the fifth and third layers on 9.28498°N, 7.41875°E (VES 1); 9.28515°N, 7.41789°E (VES 5); 9.28437°N, 7.41793°E (VES 8); 9.28394°N, 7.41792°E (VES10). Furthermore, the outcome of this work revealed the lithology of the region investigated. Five distinct layers of varying thicknesses and depths were displayed: Top soil, Clay, Sandy clay, Fractured and Basement Rocks. From the collated readings, the derived average thicknesses of topsoil, sandy clay and clay are 0.8 m, 10.2 m and 7.06 m respectively.
Environmental impact assessment of the potability of water from bore-hole, hand dug well and stream at Itagunmodi gold deposits Southwestern, Nigeria using FORTRAN algorithm for monitoring leachates and interpreting physicochemical data of contaminants in groundwater
(Academic Journals, 2015-01) Adetoyinbo, A. A.; Adelegan, F. T.; Bello, A. K.
This study determined the quality of surface and underground water in Itagunmodi in Nigeria. Physicochemical analysis of water samples collected within gold mining area and the water consumed in the town was carried out to determine their hygienic conditions. The major objective of this study was assessment degree of groundwater pollution around the mining sites and the available water consumed in the town. Four major sources of water were analyzed. Several physical and chemical parameters were tested in roundwater, these include pH, total solids (TS), total dissolved solids (TDS), conductivity, total alkalinity, total hardness (TH), chloride (Cl-1), sulphur (S), heavy metals (Pb, Zn, Cu), major cation (Mg). The results show that the parameters are within the standard acceptable levels which are required for drinking water adapted from World Health Organization. The pH of the samples was suitable for drinking according to the World Health Organization standard. For a safe drinking water, the pH should be between 6.5 and 8.5); it can be said that the water quality of the samples are fairly good based on the monitored elements and physicochemical characteristics.
Estimation of outflow discharge from an ungauged river: case study of Awara in Ondo State Southwestern, Nigeria
(2017-10) Alabi, O. O.; Sedara, S. O.; Adetoyinbo, A. A.; Akinwande, D. D.
Flooding has become the annual experience of Nigerian cities especially in the southwestern states of country, precisely Ondo state. This study uses Muskingum Cunge method river routing techniques to compute outflow discharge and to determine hydrographs of inflow and outflow pattern of Awara river Ikare Akoko, North east LGA in Ondo State, Southwestern of Nigeria. The Muskingum Cunge method of flood routine reflects the interrelationship existing between the inflow and outflow of river. The average monthly inflow discharge for twenty years was worked on using Muskingum Cunge method of flood routine. Observation from the hydrograph shows th'at inflow peak occurs in the month of April, while the outflow in the same month is very low. This implies that the month of April is a critical month that needs a special attention and there is a need for channelization of this river before the month of April every year, in order to prevent occurrence of flooding whenever there is heavy rainfall.
Fabrication of an induction coil magnetometer for geomagnetic field measurement
(2010-11) Adetoyinbo, A. A.; Hammed, O. S.; Ogunsua, B. O.
The measurement of magnetic variations within the low frequency range of 0.1 to 40Hz requires a highly sensitive magnetometer. A magnetometer based on the induction coil principle was designed, simulated, and constructed in this research. The search coil was designed by winding 4,500 turns of insulated coil on PVC pipe with 3 silicon-iron strips mounted on the PVC for higher magnetic susceptibility. The sensory method of the coil is based on the faraday’s law of electromagnetic induction. The output of the coil was amplified and filtered with a band pass electronic system designed to pass the desired frequency range of 0.1 to 40Hz. A simple calibration system using the Helmoltz coil pair was designed for the calibration of the sensor to determine the conversion factor of the output root mean square (r.m.s.) voltage with the external magnetic field (Hs), since the Helmoltz coil can generate very uniform magnetic field up to 25% or more of the covered area from the centre axis. The output voltage and applied magnetic field obtained as the calibration data were fitted into a linear graph. A relatively high sensitivity of 299mv/pT was obtained.
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.
Fortran algorithm for monitoring leachates and interpreting physico-chemical data of contaminants in ground water
(2012) Adetoyinbo, A. A.; Adewole, O. O.
A FOTRAN 90 algorithm was developed to interpret leachate geochemical data of polluted ground water in Lagos, based on 19 selected physico-chemical parameters adopted by the United States Geological and Environmental Survey Agency in compliance with the World Health Organization (WHO) prescribed standards for safe water consumption. By applying the Fortran program, the portability of leachates contaminated water were ascertained in compliance with WHO requirements.
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.
The geological and geochemical characteristics of soil on Ore deposits, Itagunmodi gold deposits as a case study
(2011-02) Adetoyinbo, A. A.; Bello, A. K.; Hammed, O. S.
This work examines the geological and geochemical characteristics of soil on Ore deposits on the formation and maturity of (SHDG) deposits in Itagunmodi, Osun State, Nigeria. Although, some investigations have been carried out on their geological and geochemical characteristics in general, most of the studies are based on limited database. The source and the nature of the gold in the deposits are still not clear. The major objective of this study is to determine the geochemical characteristics of host soil. The plots of major elements collected from five different locations in the mining areas named A-E and three locations outside the mining areas F-H shows that the concentrations of the element is higher within the mining site than area outside the mining site.
Gravity anomaly and basis symmetric matrix Interpretation for residuals
(2018) Adetoyinbo, A. A.; Ewumi, T. O.
Gravity method has tremendously pervaded the field of geophysical exploration and thus extensively discussed and vividly illustrated in this work. The basis for symmetric matrix data gravity interpretation was earlier proposed, then extended to residuals and interpretation. A symmetric matrix representation is discussed further to residuals, spectral, interpretation, and optimistically forms a veritable tool for gravity data interpretation. The fundamental law of gravitational attraction is essential in delineating gravity data interpretation and the gravity effect or anomaly representation is evidently expressed by a finite difference matrix in the discussion. A computational extension can be done based on the symmetric matrix representation with available gravity data and a vivid illustration for anomaly and residual computation has been made
High temperature and pressure impact on volume of Ore deposits; itagunmodi gold deposit, South West Nigeria as a case study
(2012) Adetoyinbo, A. A.; Bello, A. K.; Hammed, O. S.
An understanding of the Earth’s interior depends on information about the behavior and properties of matter under high pressures and temperatures. An equation of state that connects pressure (P), volume (V), and temperature (T) is very important. This work examines the impact of high temperature and pressure on the formation and maturity of sediment-hosted disseminated gold (SHDG) deposits in Itagunmodi, Osun State, Nigeria located in the clayey soil types derived from variably migmatised gneiss, biotite-and-biotite-homblende- gneiss and weathered amphibolites respectively. The melting temperatures of gold were determined by differential thermal analyses. After application of appropriate correction for the effect of pressure on emf of thermocouples, the melting curves are linear with the isothermal volume of the melting solid to within the precision of the measurement. This melting point of gold at variable high temperature and pressure, if extrapolated could be used as a primary standard for measurements.
Mathematical modelling of N-stage rocket
(Medwell Journals, 2010) Adewole, O.O.; Adetoyinbo, A. A.