Department of Physics.

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Path Loss Prediction on Earth-Space Link Using Statistical and Time Series Approach at Ka-Band in Abuja, North Central Nigeria
(ICSAEES-2024, Lagos, Nigeria, 2024) Arijaje, T. E.; Omotosho, T. V.; Aizebeokhai, A. P.
Predictive path loss modelling is essential in designing wireless communication systems. However, the empirical methods of path loss prediction are inaccurate as the empirical models cannot be implemented outside the area or region where they are developed. This study focuses on improving the prediction of path loss using statistical approaches such as multiple linear regression (MLR) and time series models using eight (2014 – 2021) data retrieved from the global precipitation measuring mission (GPM) at Ka-band. The step-wise selected method was adopted for the multiple linear regression (MLR). In the exponential smoothing method, weighting is carried out exponentially, decreasing in the direction of the older values. The MLR analysis revealed that the MLR model performs well, with an accuracy of 99.52%. The R2 value of 99.52% indicated a strong correlation between the estimated and predicted path loss in the model. PL = 18.706 0.98459 − Pr +1.60027Pt + 0.99808Gr The P-value of the regression model is 0.000, indicating that the model estimated by the MLR procedure is statistically significant at a level of 0.05. Also, the results showed that the transmitted antenna gain is the most contributed predictor in the path loss with a value of 1.60027 dB. Likewise, the results from the exponential smoothing models revealed that the single exponential smoothing (SES) model performs better than the double exponential smoothing model with a mean absolute percentage error (MAPE) of 14.47%, indicating that the model's performance is good because the MAPE value falls within 10 – 20%. The mean absolute deviation (MAD), mean square deviation (MSD), and smoothing constant are 0.3215, 0.2313, and 0.9685, respectively. Striking a balance, the application of MLR and the SES models will improve wireless communication systems in Abuja, the North Central region of Nigeria, at Ka-band. Therefore, engineers and policymakers in the Nigerian telecommunication industry should assess the impacts of path loss within the study locations towards sustainable telecommunications and infrastructure (SDG goal 9) for planning and setting radiowave propagation technologies in the study locations and Nigeria at large.
Seasonal Variation of Total Attenuation between Airborne Platform and Earth Station in South-West Region, Nigeria
(7th International Conference on Science and Sustainable Development and Workshop, 2024) Arijaje, T. E.; Omotosho, T. V.; Aizebeokhai, A. P.; Akinwumi S. A.
The seasonal variation of total attenuation in the southwest region of Nigeria has been computed using eight (8) years dataset at Ku- and Ka-band of the transmitted power of the radar, transmitted antenna gain and the received antenna gain of the satellite retrieved from the archived of the GPM. The results obtained fluctuates between the seasons at Ku- and Ka-band. From the results obtained at Ku-and Ka-band, the results from analysis showed that the peak total attenuation was recorded between the early (MAM) and late wet (JJA) season when the intensity of rainfall is maximum in the South-West region. As a result, the effect on the airborne-earth station link will be severe which may further lead to signal outage. However, the state where the highest total attenuation was consistent is Lagos state. These seasons and Lagos state must be taking into consideration by engineers and radiowave propagation group when planning and sitting radiowave propagation in the study area.
INVESTIGATION OF LEACHATE INFILTRATION ON GROUNDWATER USING GEO RESISTIVITY AND NATURAL ELECTRIC FIELD METHOD AROUND OJOOU-OLAYANJU’S DUMPSITE, ADA, SOUTHWESTERN NIGERIA
(Nigerian Journal of Technology (NIJOTECH) Vol. 43, No. 1,, 2024) Adeniji, A. A.; Ajani, O. O.; Adagunodo. T. A.; Kolawole, T.
The investigation of groundwater within the dumpsite environment is highly important in geophysical study. This is because the extent of interaction between the aquiferous medium and the contaminated zone could pose a serious threat to the end users especially humans when consumed. This research aimed at investigating leachate infiltration and its potential influence on groundwater at Ojoou Olayanju's Dumpsite using combining geo-resistivity and natural electric field (NEF) methods. In this study, five dipole-dipole and five NEF measurements were obtained using the Omega resistivity meters and PQWT-150 equipment respectively. The dipole-dipole method was deployed to obtain a 2D near-surface pseudo-section, and the NEF method was used to obtain the frequency curve and profile maps of electric potential difference. The dipole dipole results revealed the lateral variation in the resistivity along the traverses, suggesting that the materials within this near-surface are heterogeneous, and the closely spaced contours' varying gradients indicate fracture, which would facilitate potential leachate filtration. The NEF results revealed curves, and a subsurface image with respect to depth and profile distance. The points of convergence signals on the frequency model correspond to a medium with low resistivity on the profile map. The conductive medium is seen as being saturated with leachate, which suggests that very large portion of the study area around the dumpsite has been contaminated by leachate. Conclusively, it was revealed that leachate filtration is evidence especially at the topsoil and due to the presence of fractured zones, the groundwater quality is at risk of contamination by continuous filtration of leachate.
Hydrogeophysical Investigations for Groundwater Resources Sustainability in Parts of the Eastern Dahomey Basin, Nigeria
(ImprintCRC Press, 2024) Oyeyemi, Kehinde D.; Aizebeokhai, Ahzegbobor P.; Okon, Emmanuel E.; Oladunjoye, Michael A.
Geophysical surveys including geoelectrical resistivity and time-domain induced polarization (IP) techniques have been conducted in Ota in Eastern Dahomey Basin. Thirty vertical electrical sounding (VES) profilings were conducted using a Schlumberger array with an AB/2 range of 180–240 m. Two profiles of 2D electrical resistivity imaging and IP surveys were conducted with Wenner array configuration. The delineated geoelectric layers are topsoil (lateritic clay), clayey sand, sandy clay, sand, and shale or clay units. Two aquifers were delineated in the area with the upper aquifer being a fine-to-medium sand and the lower aquifer of a poorly medium-to-coarse sand unit. The aquifer resistivity ranges are 347.4–411.4 https://www.w3.org/1998/Math/MathML" display="inline"> Ω m https://www.w3.org/1999/xlink" xlink:href="https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west 1.amazonaws.com/9781003454908/c35032d3-f666-459f-b1ca a1b405d5a7b1/content/C025_equ_0001.tif"/> and 104.5–143.3 https://www.w3.org/1998/Math/MathML" display="inline"> Ω m https://www.w3.org/1999/xlink" xlink:href="https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west 1.amazonaws.com/9781003454908/c35032d3-f666-459f-b1ca a1b405d5a7b1/content/C025_equ_0001.tif"/> for the upper and lower aquifer, respectively. The hydraulic parameters of both aquifers were estimated using established mathematical relations. The upper aquifer has porosity, hydraulic conductivity, and transmissivity ranges of 19.1% 21.8%, 10.8 × 10−2 (m/s)–17.0 × 10−2 (m/s), and 1.49–2.4 (m2/s), while the lower aquifer unit has porosity, hydraulic conductivity, and transmissivity values of 43%–55%, 248 × 10−2–782 × 10−2 (m/s), and 34.72–101.66 (m2/s). High hydraulic parameters in the two aquifers are important for sustainable groundwater development, ensuring efficient use and protection of this vital resource. Their significance extends to promoting regional economic growth by supporting agriculture, industries, and tourism. Mapping faults in the area highlights the need for hydrogeological modeling to discern their impact on aquifer parameters, vital for precise resource management, and predicting potential effects on availability and quality.
NS23C-03 Geophysical Imaging for Assessing Restored Wetlands' Soil Properties, Infiltration Rates, and Potential Surface Groundwater Interaction
(AGU24, 2024) Aizebeokhai, Ahzegbobor P.; LaPoint, Hannah N.; Doro, Kennedy O.
Efforts to reduce nutrient loading into Lake Erie include restoring old farm fields within Northwestern Ohio to wetlands. With a history of intensive farming, these fields are characterized by legacy nutrients, altered soil structure and drainage tiles. Inadequate knowledge of soil properties distribution, drainage tile locations and potential surface groundwater interaction at the sites limits restoration projects' effectiveness. This study combined a rapid geophysical site characterization framework with in-situ soil cores and hydraulic tests to assess variations in soil properties and hydraulic processes. We used a 250MHz PulseEkko ground penetrating radar (GPR) system and an EM38-MK2 conductivity meter to acquire GPR and electromagnetic imaging (EMI) measurements at selected wetlands with the equipment towed behind a utility terrain vehicle to allow extensive spatial coverage. Electrical resistivity (ER) data were acquired along transects using a Supersting R8 resistivity meter with an 84-electrode switch box. The ER measurement was done using a dipole-dipole array with 1m electrode spacing. Co-located soil cores were collected along the transects for laboratory soil moisture content, organic matter and texture measurements. In contrast, in-situ measurement of soil-saturated hydraulic conductivity was done using a SATURO infiltrometer. The apparent electrical conductivity (ECa) and ER distribution show comparable subsurface structures and parameter zones, and ECa correlates strongly with soil moisture, organic matter and silt contents (R2 >0.7; p-value <0.002). The ECa also notably correlates with the soil saturated hydraulic conductivity (R2 = 0.85), indicating the possibility of using EMI to rapidly characterize potential water retention zones (low Ksat) in restored wetlands. The spatial distribution of geophysical parameters depends linearly on soil properties distribution. This geophysical-soil-property relation, developed through a rapid site characterization framework, allows for improved soil sampling and monitoring plans. This study shows the effective application of EMI, GPR, and ER for pre- and post restoration characterization of old farm fields with legacy nutrients and drainage tiles that contribute to nutrient loading into Lake Erie.
Application of VLF-EM response and geoelectrical sounding in groundwater investigation around an active dumpsite
(Application of VLF-EM response and geoelectrical sounding in groundwater investigation around an active dumpsite, 2024) Adeniji, A. A.; Ajani, O. O.; Adagunodo, T. A.
An integrated geophysical method combining very low frequency electromagnetic (VLF-EM) and vertical electrical sounding (VES) methods were carried out around Adaland, Southwestern Nigeria, located within latitude 70 54' 0" and longitude 40 43' 0", with a view to investigate the possible impact of dumpsite on groundwater.This is the major study in the environment to offer extensive evidence regarding the suitability of obtaining quality groundwater. In this research, eight VLF-EM and twelve VES data sets were generated, which were then used to estimate the linear structure, bedrock formation, subsurface geological characteristics, and identification of leachate pathways. The VLF-EM data were analyzed by employing Karous_Hjelt and Microsoft Excel, while the VES data were investigated using the WinRESIST software. TheVLF-EM results confirmed the presence of conductive zones, which might be due to fracture, fault and contact zones or weathered basements. The lithological units acquired from the electrical resistivity results revealed four geoelectrical layers such as topsoil, weathered-based, fractured basement and fresh basement. However, the identified weathered layers and fractured basements from the geoelectrical sections and the corresponding Karous and Hjelt (K-H) pseudo sectionresults around the dumpsite, constitute the main passages for the possible impact of the open dumpsite on groundwater quality, since leachates from the dumpsite could slowly percolate downwards from the topsoil to the water table. Therefore, the impact of the dumpsite on the groundwater is caused by the inadequate clay materials, near-surface features such as fractures/faults, and lateral in-homogeneity. Thus, integrating both methods has been recommended in site characterization for accessing quality groundwater around a dumpsite environment.
Modelling and Prediction of Satellite Signal Path Loss using the ARIMA models at Ku-band in Lagos State, South Western Nigeria
(ICSSD 2024 (IOP Conf. Series: Earth and Environmental Science), 2025) Arijaje, T. E.; Omotosho, T. V; Aizebeokhai, A. P.; Akinwumi S. A.; Oyeyemi, K. D.
Satellite signal path loss is the reduction of signal strength between the transmitting satellite and the receiving antennas on the earth surface. It is cause by effects such as reflection, free space loss, diffraction, refraction and absorption. It is also cause as a results of the environment, terrain contours, medium of propagation, height of antennas location and transmitting distance between the transmitter and receiver. Several methods such as the traditional methods and machine learning techniques have been explored. However, statistical method of path loss prediction has been completely utilized. In this work, prediction of path loss using the autoregressive integrated moving average (ARIMA) technique was considered. Four different ARIMA models at Ku-band were explored using eight years in Lagos State. The method consists of some steps in the run time analysis: the first stage involved identifying the ARIMA model by creating an Autocorrelation Function (ACF) and Partial Autocorrelation Function (PACF) plots and checking if the data are stationary. The second stage involved estimating the ARIMA model, which consists in testing the parameters' significance after obtaining the model's parameters. The ARIMA model is adopted if the parameters are significant. The third stage involved diagnostic checking, in which a test was carried out to see if the adopted model was statistically significant. The fourth stage involves predicting the path loss after the diagnostic process using the adopted or selected ARIMA model. From the analysis, it can be concluded that the best ARIMA model for path loss prediction in Lagos at Ku-band is ARIMA (1,0,0). The ARIMA (1,0,0) model is a better path loss prediction model than the other ARIMA models, indicating that the model parameters are significant at 0.05 with the slightest MSE error, thereby meeting the test of independence. Therefore, for sitting and planning of radio signal propagation technologies in the study location, policy-makers and engineers in telecommunication industry in Nigeria can take advantage of the results within the area of study towards sustainable tele-communication and infrastructure (SDG goal 9).
Assessing subsurface heterogenenity and infiltration capacity at a restored wetland using geophysical imaging and infiltration tests
(2025) Otchere, Nana-Aboagye; Aizebeokhai, Ahzegbobor P.; Martin-Hayden, James; Doro, Kennedy O.
Wetland soil properties and stratigraphic heterogeneity influence their water-holding capacity, 15 infiltration, and subsurface flow. Infiltration, however, depends on the soil’s saturated hydraulic 16 conductivity (Ksat) whose spatial variability at field scale is difficult to quantify. In this study, we 17 combined electromagnetic imaging (EMI) and electrical resistivity (ER) with infiltration tests to 18 assess the spatial variation in the shallow subsurface stratigraphy and Ksat at a restored wetland in 19 northwest Ohio. We used a Geonics EM38-MK2, with a transmitter and two receivers spaced 0.5 20 and 1.0 m to map the spatial distribution of the soil’s apparent electrical conductivity (ECa). The 21 ER measurements were acquired along nine transects using a SuperSting R8 resistivity meter 22 with 84-electrode and a dipole-dipole electrode array. The ER results, constrained with 23 lithostratigraphic logs, showed 0.7 m thick topsoil (silty loam) underlain by 0.5 m thick clayey 24 loam interspersed with coarser materials and alternating units of diamictons. The observed ECa 25 were relatively higher (10 – 40 mS/m) for the 0.5 m T-R spacing compared to the 1.0 m spacing 26 (8 – 36 mS/m). The spatial distribution of Ksat ranged from 0.01 – 0.9 mm/min with higher 27 values at areas with high silt and sand content. A least-squared linear regression between Ksat 28 and ECa yielded coefficient of determination (R2) values >0.62 indicating the effectiveness of 29 EMI for predicting the spatial variation of Ksat. Thus, combining geophysical imaging with field 30 infiltration tests provided valuable insights into infiltration through the soil and potential 31 subsurface flow at the restored wetland with limited details on subsurface flow.
Delineation of structural lineaments of Shaki West Southwestern Nigeria using high resolution aeromagnetic data
(Journal of the Nigerian Society of Physical Sciences, 2025) Adedokun, O. M.; Oladejo, O. P.; Alao, K. N.; Adeniyi, E. O.; Otobrise, H.; Suleman, K. O.; Adagunodo, T. A.; Adedokun, O.; Sunmonu, L. A.
Aminor earthquake, known as earth tremor, often occurs in areas prone to seismic activity. However, there is a notable gap in knowledge about earth tremors, with little documentation conducted before 1987, but a series of notable events between 1990 and 2000 prompted researchers to delve deeper into the study of earth tremors in Nigeria. Therefore, this study is aimed at delineating the structural lineaments of Shaki West Southwestern Nigeria using High Resolution Aeromagnetic Data (HRAD) to identify the underlying basement geology and define the structural framework of the study area. The study area’s aeromagnetic data of Shaki (Sheet 199) underwent processing and interpretation using Oasis Montaj software to assess basement configuration and structural integrity. The data were further enhanced using the Total Horizontal Derivative (THDR) in order to determine the orientations of the lineaments in the study area. The orientations of the lineaments obtained from THDR map revealed that the Pan African orogeny constitutes 52%; Kibaran orogeny constitutes 31%, while Liberian orogeny constitutes 17% lineaments in the study area. The upward continuation maps suggest the presence of faults at the depth range of 2.0-2.25 km. The overall depth to magnetic sources of the area is relatively shallow compared to sedimentary basement area. Based on orientation of faults on magnetic fault map obtained from the superposition of the lineaments extracted from THDR map on the geological map of the study area, three distinct set of sinistral /dextral faults were recognized in Shaki west local government area which includes: E-W, NE-SW and NW-SE fault trend. This suggests that NE-SW and NE-SE fault-set could be responsible for the tremor experienced in Shaki west southwestern, Nigeria. It is concluded that the study area is not immune from experiencing occurrences of tremors from time to time
ASSESSMENT OF AIRBORNE AND TERRESTRIAL RADIOMETRIC CONCENTRATIONS AND ASSOCIATED HEALTH RISKS IN SELECTED LOCATIONS IN SOUTHWEST NIGERIA
(Covenant University Ota, 2025-08) MORAKINYO, Ruth Omoseeke; Covenant University Thesis
Radiation is an inevitable part of the human environment, both from terrestrial and anthropogenic sources. Elevation of radiation levels in an environment above the threshold limit is detrimental to man and the ecosystem. Therefore, monitoring the radiation level of every human environment is expedient because of the harmful effect of exposure to ionizing radiation. The radiometric data of selected locations in southwest Nigeria was collected from the database of the Nigeria Geological Survey Agency (NGSA) and analysed using the Oasis Montaj software. The result of the NGSA data served as a guide in the selection of locations for in-situ assessment using an RS-125 handheld gamma spectrometer. Soil and water samples were collected in those locations and some quarry sites and analysed in the laboratory using NaI (TI) detector. The obtained activity concentrations were used to determine the radiological parameter. The absorbed dose rate for analysed aero radiometry data ranges between 31.92-214.04, 36.31-192.77, 13.82-162.02, 6.57-119.62, 10.83-116.93 and 16.4-63.70 nGy/h for Ado-Ekiti, Akure, Ondo, Apomu, Ibadan, and Ijebu-ode sheets respectively. The mean absorbed dose rate for in-situ assessment for the exact locations ranges between 38.00-149.43, 86.00-179.27, 51.21-116.53, 72.76-109.09, 84.32-194.41, 56.27-64.55nGy/h respectively. The results of soil and water samples of selected locations and quarry sites revealed that the absorbed dose rate in soil samples in 80% of the locations and 100% of the quarry sites was higher than the world average value. The estimated total annual committed dose for various categories of ages in all the water samples were higher than the world average value. The estimated annual effective dose and excess lifetime cancer risk in most locations in in-situ assessment and analysis of soil samples was higher than the global limit. Statistical analysis revealed that the concentration of 232Th contributes significantly to the absorbed dose rate in air and the total annual committed dose due to ingestion of water. In contrast, the activity concentration of 40K contributes significantly to the absorbed dose rate in soil samples in the study area. The need for potable water for the various communities in the region cannot be over-emphasized as the total annual effective dose for all categories of ages was higher than the reference limit. The study concludes that analysis of aero-radiometry data can be an effective guide in monitoring the radioactivity level of an environment.
High-resolution non-invasive mapping of vertical heterogeneity in sandy soils of the Oak Openings Region using electromagnetic imaging and ground penetrating radar
(Research Square, 2025-08) Aizebeokhai, Ahzegbobor P.; Urom, Obinna; Doro, Kennedy O.
Abstract 10 Traditional soil investigation methods involve laboratory analysis on soil cores or direct 11 measurements of soil properties with in-situ sensors. These methods are, however, destructive, 12 labour-intensive, and ineffective in capturing the spatial variation of soil properties. Geophysical 13 methods provide a non-invasive approach to rapidly characterize soil properties distribution. Gaps, 14 however, exist in the use of non-contact-based geophysical methods such as ground penetrating 15 radar (GPR) and electromagnetic imaging (EMI) for characterizing the vertical variation of soil 16 properties. This study assesses the use of EMI and GPR for quantifying the vertical variation of 17 soil moisture content (SMC), soil organic matter (SOM), and soil texture. Co-located EMI and 18 GPR surveys were conducted along 12 transects at the Stranahan Arboretum research site in 19 Toledo, Ohio. Soil samples collected from nine locations along the transects were segmented into 20 63 subsamples and analysed for SMC, SOM, and soil texture. Apparent electrical conductivities 21 (ECa) from EMI were inverted to obtain lateral and vertical variations of soil electrical conductivity 22 (EC), which captures three major lithostratigraphic units (sand, silty loam, and silt) found in soil 23 cores within the top 2.0 m. Soil EC correlates with SMC, SOM and soil texture, with coefficient 24 of determination (R2) ranging from 59-91%. The GPR radargrams show reflectors consistent in 25 delineating sandy and silty clay soils but unable to distinguish between sand and silt. These results 26 validate the effectiveness of using EMI and GPR to delineate vertical variation of soil properties 27 and characterize stratigraphic heterogeneity, expanding the possibilities for non-invasive three28 dimensional (3D) soil properties mapping