Papers by Kehinde D . Oyeyemi
Hydrogeological characterization of aquifers requires some knowledge of hydraulic parameters for ... more Hydrogeological characterization of aquifers requires some knowledge of hydraulic parameters for efficient groundwater resource assessment and management. Traditional techniques for determining hydraulic parameters are generally invasive and expensive, and can only provide point information which is inherently unable to accounts for the spatial variability of the subsurface hydrologic properties. Non-invasive or minimally invasive geophysical techniques, which are relatively inexpensive and have capability of providing subsurface information over wide spatial resolutions, offer alternative approach to estimating hydraulic parameters. The present study is an attempt to estimate the hydrogeophysical parameters of the delineated aquifer units from surface geoelectrical resistivity measurements in Iyesi and its environs, southwestern Nigeria. The estimated hydrogeophysical parameters define the aquifer properties for the assessment and management of groundwater resource in the area.
The impact of air pollution on human health can be communicated through the application of air qu... more The impact of air pollution on human health can be communicated through the application of air quality index (AQI). This has been underutilized in the developing countries due to inadequate technology. In this study, ambient fine particulate matter (PM2.5)-AQI in selected industrial areas in Ogun State, Nigeria was evaluated during weekends of wet season. PM2.5 samples were collected on Teflon filters using Environtech gravimetric sampler. AQIs were further computed following the United States Environmental Protection Agency (US EPA) formulae. The result showed that for the major part of the wet season, the weekend air quality was categorized as “unhealthy” in all the industrial sites. An indication of possible adverse health concerns especially for the sensitive group. In addition, gradations of 0 to 50, representing the good AQI category was not observed. Therefore, synergy from Engineers, Scientist and Policy makers is required towards the availability of sensitive and low cost i...
Applied Geophysics, 2016
Conventional artifi cial neural networks used to solve electrical resistivity imaging (ERI) inver... more Conventional artifi cial neural networks used to solve electrical resistivity imaging (ERI) inversion problem suffer from overfi tting and local minima. To solve these problems, we propose to use a pruning Bayesian neural network (PBNN) nonlinear inversion method and a sample design method based on the K-medoids clustering algorithm. In the sample design method, the training samples of the neural network are designed according to the prior information provided by the K-medoids clustering results; thus, the training process of the neural network is well guided. The proposed PBNN, based on Bayesian regularization, is used to select the hidden layer structure by assessing the effect of each hidden neuron to the inversion results. Then, the hyperparameter α k , which is based on the generalized mean, is chosen to guide the pruning process according to the prior distribution of the training samples under the small-sample condition. The proposed algorithm is more efficient than other common adaptive regularization methods in geophysics. The inversion of synthetic data and fi eld data suggests that the proposed method suppresses the noise in the neural network training stage and enhances the generalization. The inversion results with the proposed method are better than those of the BPNN, RBFNN, and RRBFNN inversion methods as well as the conventional least squares inversion.
IOP Conference Series: Materials Science and Engineering, 2019
Recently, there has been an increase on the use of waste materials for development of new materia... more Recently, there has been an increase on the use of waste materials for development of new materials for construction. This is due to the need for sustainable development which emphasizes on waste reduction, reduction of greenhouse gases (GHG), greener clean environment and conservation of raw resources. This study examines the appropriateness of clay brick waste in powder form as a suitable material for partial substitute of cement in mortar. The clay bricks were obtained as generated waste materials from a brick producing factory in Lagos metropolis and then subjected to grinding. Tests which include; specific gravity, particle size distribution, x-ray fluorescence and scanning electron microscopy were carried out on the pulverized clay brick material (CBP). Further, it is used to partially replace cement in mortar at replacement percentage of 0, 5, 10, 20, 25, 30, 40 and 50% using a mix ratio of 1: 2.75 at 0.45 water-cement ratio. Compressive strength and strength activity index t...
Journal of Physics: Conference Series, 2019
Limestone exploration has numerous advantage to the nation’s economy. However, major anthropogeni... more Limestone exploration has numerous advantage to the nation’s economy. However, major anthropogenic activities such as mining of such mineral deposits causes environmental contamination due to heavy metals pollution. The presence of heavy metals such as lead, cadmium, mercury and arsenic can interfere with the biochemical pathways by interaction with enzymes and proteins. They equally have the capacity to alter the DNA repair mechanism and act as the inducers of carcinogenesis. The focus of the research is therefore to detect the extent of heavy metals contaminations within the sampled Ewekoro limestone, southwestern Nigeria and to ascertain the risks they posed to the quarry workers, miners and the people residing in the study area.
Water
Geoelectrical resistivity measurements were conducted in five locations within the eastern portio... more Geoelectrical resistivity measurements were conducted in five locations within the eastern portion of the Dahomey basin for the purpose of subsurface evaluation and detecting saturated zones. The locations are Covenant University (L1), Bells University (L2), Oju-Ore-Ilogbo Road (L3), Obasanjo-Ijagba Road (L4), and Iyana Iyesi (L5). The study was carried out to avert the common challenges of drilling low-yield groundwater boreholes in the area. A total of 30 Vertical Electrical Soundings (VES) and five two-dimensional Electrical Resistivity Tomography (ERT) data sets have been acquired along the study areas. The geoelectrical resistivity results were integrated with the borehole logs to generate the spatial distribution of the subsurface lithologies in the area. The delineated subsurface lithologies include the topsoil (lateritic clay), clayey sand, sandy clay, fine silty sand, coarse sand, and shale/clay units. The fine silty sand and coarse sand units were identified as the two mai...
We have assessed the extent of metal (Pb, Cd, Zn, Ni, Co, Cr, Cu, Mn, and Fe) pollution in the ag... more We have assessed the extent of metal (Pb, Cd, Zn, Ni, Co, Cr, Cu, Mn, and Fe) pollution in the agricultural soils and vegetables from Ifo village in southwestern Nigeria. Ten (10) samples each of soil and vegetables are collected from the study area and are subjected to analysis. The concentrations of Pb, Cd, Zn, Ni, Co, Cr, Cu, Mn and Fe in soils are 16.9-68.4, 0.6-0.8, 54-89, 30.8-50.2, 10.6-22.3, 100-218, 12.3-24, 515-2215 and 33900-45600 ppm respectively while the concentrations in vegetables are 0.768.63, 0.05-0.42, 26.2-80.8, 1.1-17.8, 0.1-6.6, 2.4-77.2, 6.01-11.6, 23-360 and 300-18610 ppm respectively. Enrichment factor (EF), geoaccumulation index (Igeo) and transfer factor (TF) are determined and the respective levels of contamination are evaluated in the study area. Correlation analysis are also done to determine the relationship between the metals. The results of EF show that metals in the soil samples vary from no enrichment to minor enrichment, with Cd showing the highes...
Sustainability
Water is a natural resource; its availability depends on climatic and geological conditions, and ... more Water is a natural resource; its availability depends on climatic and geological conditions, and it is invariably controlled by human activities. Agbado-Ijaye lies within a coastal area, where local communities have been facing incessant water shortages, especially during the dry season. This study investigated the groundwater-bearing geological unit(s) using hydrogeophysical techniques in the coastal environment. The electrical resistivity technique, involving vertical electrical sounding (VES) and two-dimensional (2D) electrical resistivity imaging via Wenner array electrode configuration, was used to characterize the geoelectric distribution. Twenty VES stations were investigated and current electrodes (AB/2 m) spacing expanded from 1–200 m; four 2D electrical resistivity imaging traverses having a length of 200 m each and interelectrode spacing of 10 m (level 1) to 60 m (level 6) was adopted. Four geoelectric units were delineated, namely: topsoil (15–251 Ωm), clayey (28–100 Ωm)...
Arabian Journal of Geosciences, 2021
Delineating crystalline basement aquifers with adequate capacity to store and transmit sufficient... more Delineating crystalline basement aquifers with adequate capacity to store and transmit sufficient groundwater is quite challenging as substantial spatial variability predominantly marked the basement aquifers. Electrical resistivity is a non-invasive geophysical technique for delineating weathered and fractured zones that permit groundwater accumulation in the basement rocks. This study uses two-dimensional (2D) electrical resistivity imaging (ERI) to delineate the weathering profile developed above the crystalline basement rocks and thus assesses the groundwater potential of the aquifer systems in Basiri, Ado-Ekiti, southwestern Nigeria. The study evaluated the reliability of the 2D ERI images by computing the depth of investigation (DOI) index to predict the depth extent at which the 2D resistivity models are no longer reliable. This approach can be used to minimise the mismatch between the resistivity models and subsurface targets, particularly in complex and subtle hydrogeological conditions as in the crystalline basement complex. This study indicates that the weathering profile developed into a two-layered aquifer system—a low yield shallow saprolite aquifer overlying a deeper fractured bedrock (saprock) aquifer with greater capacity to support adequate drawdown for high yield.
Advances in Science, Technology & Innovation, 2019
Electrical resistivity imaging (ERI) is widely used for near-surface characterization in geophysi... more Electrical resistivity imaging (ERI) is widely used for near-surface characterization in geophysical applications for hydrogeological, environmental and engineering investigations. This study involves the application of the two-dimensional (2D) electrical resistivity imaging (ERI) to delineate structures that are suitable for groundwater occurrence in a crystalline basement complex terrain. The dipole-dipole array, which is sensitive to weathered and fractured zones commonly associated with groundwater accumulations in a basement complex, was deployed for the measurements. The survey was conducted to locate possible points for siting productive boreholes in a site at Abeokuta, southwestern Nigeria, as previous boreholes and wells drilled within the study site failed.
IOP Conference Series: Earth and Environmental Science, 2021
Buildings are essential structures that provide mankind with accommodation in the form of offices... more Buildings are essential structures that provide mankind with accommodation in the form of offices, factories, residences, etc. Building Infrastructure aid to increase the Gross domestic product of nations by meeting the present needs as well as helping in the reduction of future deficiencies. Unfortunately, in developing countries like Nigeria, regular occurrence of collapse of buildings in concrete materials have dealt a terrible blow to the nation, leading to losses in the form of death and damage to properties. This study aims to show the trend within the period of 2013 to 2019. This study used statistical methods to assess the fatality rate, types of buildings affected, frequency of occurrences and the causative factors. The result indicates that the year2017 witnessed 14 collapse incidences making it the highest within the study period in Lagos state. Furthermore, 204 persons lost their lives in 2014, making it the highest within the period. The results obtained showed that the...
Day 3 Wed, August 04, 2021, 2021
Machine learning methods have been applied to predict depths of fluid loss in hydrocarbon explora... more Machine learning methods have been applied to predict depths of fluid loss in hydrocarbon exploration.During drilling, lost circulation can be described as the unpleasant loss of all or part of drilling mud or fluid into the immediate formations or affected formation by excessive hydrostatic pressure, sufficient to fracture the formation or expand existing fractures encountered during the drilling process. In this study, we deployed Python codes of Support Vector Machine (SVM) and Decision Tree (DT) methodsto categorical data obtained from drilling operations in a producing field to predict lost circulation occurrence. The modelsleveraged the capability of both SVM and DT to achieve binary classification by adopting flow-out percentage of less than 70 percent as the points of lost circulation. That is, < 70% is represented as Loss and > 70% represented asNo Loss. Prediction models were applied to 10 input variables preprocessed with principal component analysis (PCA) to reduce...
Electrical resistivity tomography (ERT) and time domain induced polarization (IP) techniques has ... more Electrical resistivity tomography (ERT) and time domain induced polarization (IP) techniques has been used to assess the spatial variability of the soil petrophysical properties in Covenant University Farm, Ota, southwestern Nigeria. Apparent resistivity and chargeability of the induced polarization effect were concurrently measured along six traverses using Wenner array. The observed data were inverted to produced 2D electrical resistivity and chargeability models of the soil. The inverse models were used to delineate the tilled layer from the untilled layer, and qualitatively assess the degree of compaction and lateral thickness of the soil. Other petrophysical properties such as amount of clay volume, moisture content and organic matter in the soil which are related to the electrical conductivity of the soil were also inferred. The study demonstrates the effectiveness of ERT and time domain induced polarization techniques for accessing the variations of soil conditions in large t...
Thisarticleevaluatestheoccurrenceof0 r M r 8 earthquakedata setsfortheperiodof50years(thatis,Janu... more Thisarticleevaluatestheoccurrenceof0 r M r 8 earthquakedata setsfortheperiodof50years(thatis,January1,1966toDecember 31,2015)inAfricanandWesternAsiaregion.Itisboundedby latitude40° S to40° N andlongitude30° W to60° E withthefocal depthof0–700km.Seventyseventhousand,sixhundredand ninety-sixdatapointswerepresentedfortheanalysis.Thedata usedwereextractedfromearthquakecatalogofAdvancedNational Seismicsystemvia http://quake.geo.berkeley.edu/cnss/, anofficial websiteoftheNorthernCaliforniaEarthquakeDataCentre,USA. Eachdatumcomprisedtheearthquakeoccurrencedate,timeofthe earthquakeoccurrence,epicenter’s coordinates,focaldepthand magnitude.TheGutenberg-Richter’s relationshipbeingthelongest observedempiricalrelationshipinseismology,analysisofvariance andtimeserieswereusedtoanalyzetheseismicityofthestudy area.Annualdistributionsofearthquakeoccurrencebasedon magnitudevariationswiththelimit0 r M r 8 werepresented. ThetwoconstantsaandbintheGutenberg-Richter’s equation, magnitudeofcompleteness(MC)...
IOP Conference Series: Materials Science and Engineering, 2019
Utilization of clay brick wastes for production of high strength eco-concrete enables the combat ... more Utilization of clay brick wastes for production of high strength eco-concrete enables the combat of raw resources depletion due to excessive mining as well as mitigating environmental pollution caused by demolition of old brick structures in an effort to achieve environmental sustainability in line with the sustainable development goals (SDGs). This study investigates the beneficial usage of crushed clay brick as partial replacement for natural sand in producing high strength eco-friendly concrete. The replacement percentages of the crushed clay brick in respect to sand are 0, 10, 20, 30, 40 and 50% by weight using a mix proportion ratio of 1:1:2 at a constant water-cement ratio of 0.25, aiming at the 28 days compressive strength of about 40 MPa. The chemical characterization of the crushed clay brick and cement was conducted via X-ray fluorescence (XRF). The mechanical properties tests were performed on about 80 specimens using 100 x 100 x 100 mm for cubes, 100 x 100 x 500 mm for b...
IOP Conference Series: Materials Science and Engineering, 2019
In an attempt to ensure sustainability of construction materials, efforts were being made to reus... more In an attempt to ensure sustainability of construction materials, efforts were being made to reuse some non-biodegradable waste materials as substitute materials in mortar production. Sand is a major constituents in the production of mortar, however, using waste materials such as glass as partial or complete substitute for sand in mortar production will ensure the reduction on the needs to dredge for it, thereby preserving the very valuable natural sand resources within the environment. Furthermore, the use of crushed waste glass as a replacement for sand in the production paving stones will ensure that the paving stones are ecofriendly thereby eliminating the challenges of discriminate dumping of glass wastes in landfill. This research investigates the utilization of crushed waste glass as partial and complete replacement for natural sand in cement mortar for the production of interlocking paving stones (IPS). The waste glass was varied at various percentage proportions by weight to replace the fine aggregate in the cement mortar mixes. Laboratory tests which includes chemical composition, particle size distribution, specific gravity, and compressive strength were carried out on the crushed glass materials, sand and paving stone samples respectively. The obtained results show that the both the load and non-load bearing interlocking paving stones containing 20% crushed waste glass exhibited better performance in strength development than the control and other paving stone mixes containing various content of waste glass materials. This study demonstrates clearly that waste glass can be adopted to produce eco-friendly interlocking paving stones, and this will help both in the sustainable management of glass wastes and greening of the environment.
Journal of Physics: Conference Series, 2019
The optimum angle of tilt for PV system is very important for best performance in the generation ... more The optimum angle of tilt for PV system is very important for best performance in the generation of power and other related use of photovoltaic. This work, reviews the best angle of inclination for a stand-alone photovoltaic panel. The consideration of various studies has been looked at in line with some models. It was observed that the yearly fixed angle of tilt is close to or same as the latitude for a given location, although this may not be appropriate for use in other locations. The annual optimal angle of tilt of some locations were closely related in value i.e. 20.50 o , 20.50 o , 21.50 o , 20.20 o , 21.30 o and 22.40 o. The best electrical performance for the PV system was observed to be above 1598kWh/m 2 at20 o inclination facing south. Hencethe value of the optimum angle of tilt for best electrical performance of an array of stand-alone PV system could vary between 0 o and 90 o depending on the location latitude.
Uploads
Papers by Kehinde D . Oyeyemi