The Nigerian Journal of Applied Physics
Seasonal Variability and Transition Dynamics of Temperature and Windspeed Regimes in Southwestern Nigeria
This study investigated the seasonal variability and transition dynamics of temperature and windspeed regimes in South-west, Nigeria using Fuzzy Markov Model. Daily Temperature and Windspeed data for the South-west States (Lagos, Osun, Ogun, Ondo, Ekiti and Oyo) in Nigeria from 1991 to 2020 (30 years) was obtained from National Aeronautic and Space Administration (NASA) meteorological center. Atmospheric variables often exhibit uncertainty, gradual transitions, and overlapping climatic states that cannot be adequately represented using conventional deterministic classification methods. To address this limitation, fuzzy logic was employed to quantify the degree of belonging of temperature and windspeed conditions to different atmospheric regimes, while transition structures were analysed using fuzzy transition matrices. The climatic variables were categorized into Low/Moderate/High windspeed regimes and Cool/Normal/Hot temperature regimes. The Markov Chain Model result reveals that the high diagonal temperature and windspeed transition probabilities (0.96–0.99) across the South-west regions are highly persistent, with limited switching between regimes while the Fuzzy Model transition analysis (0.77–0.88) of temperature and windspeed across study area reveals strong overlapping atmospheric behaviour during the dry and wet seasons. This implies that climatic conditions do not exist as rigid or isolated states but instead possess varying degrees of belonging to multiple regimes simultaneously. The total elimination of moderate regimes in the Fuzzy transition temperature and windspeed matrices, where the moderate rows had zero membership values, was one of the study's key conclusions. This implies that the South-west climate system has weak, unstable, or transient intermediate atmospheric conditions. The fuzzy logic captured gradual regime transitions and overlapping state memberships that were not evident in the classical Markov framework.
Copyright (c) 2025 Inikpi Ojochenemi Agada, Terhemba Theophilus Emberga, Japheth Augustine Azogor https://creativecommons.org/licenses/by-nc/4.0
Dufour–Nanoparticle Effects of Magnetohydrodynamic Casson Nanofluid over a Stretching Sheet
The magnetohydrodynamic flow of a Casson nanofluid, governed by key thermophysical parameters, is examined in this study. The flow is generated by a linearly stretching surface and is influenced by a transverse magnetic field, thermal radiation, and internal heat generation or absorption. To simplify the governing transport equations, suitable similarity variables are introduced, reducing them to a coupled set of nonlinear ordinary differential equations. These dimensionless equations are solved numerically using a shooting technique integrated with a fourth‑order Runge–Kutta algorithm, and the accuracy of the results is confirmed through MATLAB’s bvp4c solver. The analysis reveals that a stronger magnetic field slows fluid motion while increasing temperature and concentration distributions due to enhanced Lorentz force effects. A rise in the chemical reaction parameter diminishes the velocity, thermal, and concentration fields as reactive interactions intensify. The Dufour number increases with higher temperatures and amplifies concentration through cross‑diffusion effects. In contrast, higher Schmidt numbers reduce the velocity, temperature, and concentration distributions, reflecting weakened mass diffusivity.
Copyright (c) 2026 Anselm Onyekachukwu Oyem, Onojovwo Felix Tega, Jessica Mrumun Gyegwe, Sunday Obomeviekome Imoni https://creativecommons.org/licenses/by-nc/4.0
Application Of 2-D and 3-D Electrical Resistivity Tomography of Subsurface Weak Zones for Urban Infrastructure Stability Assessment: A Case Study of Anwai in Asaba, South-South Nigeria
In the developing world, the need for comprehensive subsurface characterisation prior to infrastructure development has grown. The primary cause of the instability of the foundation, differential settlement, road failure and structural collapse is still ignorance of the subsoil. This study employed integrated two-dimensional (2-D) and three-dimensional (3-D) Electrical Resistivity Tomography (ERT) to identify subsurface weak zones and evaluate their implications for urban infrastructure stability in Asaba, Delta State, Nigeria. Electrical Resistivity data was collected along nine parallel traverses of 100 m using a PASI Earth Resistivity Meter using Wenner–Schlumberger array. The data were processed and inverted to generate 2-D resistivity sections, which were integrated into quasi-3-D depth slices, fence diagrams, and volumetric resistivity models for improved subsurface visualization. The inverted models revealed highly variable lithology, moisture content, and weathering conditions, with resistivity values ranging from approximately 20 Ωm to over 5000 Ωm. Low resistivity anomalies were interpreted as zones of weathered sediments, saturated clay lenses, and possibly groundwater accumulation along Traverses 3, 5, and 6 extending through the core area of the profiles from 1.7 m down to 11 m. These weak zones' continuity was verified by the 3-D volume diagram and iso-resistivity models, which showed how they were spatially connected over several traverses. Moderate-to-high resistivity values, suggestive of relatively competent sandy formations appropriate for foundation support, were the main characteristic of Traverses 1, 7, 8, and 9. The integrated 2-D and 3-D ERT approach effectively identified areas at risk of differential settlement, foundation instability and zones of geotechnical competence The results demonstrate that electrical resistivity imaging is a reliable, cost-effective, and non-invasive tool for urban geotechnical investigations and sustainable infrastructure planning in rapidly urbanising sedimentary environments.
Copyright (c) 2025 Elvis Ighodalo, Joy Ikiere https://creativecommons.org/licenses/by-nc/4.0
Detection and Characterization of Exoplanets Using Transit Photometry
Transit photometry has established itself as one of the most powerful and versatile techniques in exoplanet science, driving the discovery of thousands of planets and enabling quantitative studies of their physical properties. Completeness-corrected analyses of Kepler photometry demonstrate that small exoplanets (≈1–4 R⊕) are common around FGKM stars across a wide range of orbital periods. Advances in detection methodology, including transit least-squares searches and machine-learning–based validation frameworks, have significantly improved sensitivity to shallow transits and reduced false-positive contamination. Beyond demographics, transit photometry has become central to atmospheric characterization through transmission spectroscopy with facilities such as the James Webb Space Telescope (JWST). This paper discusses the methodological foundations of transit photometry, including light-curve extraction, transit detection, modelling, and validation. Key scientific outcomes from major surveys, particularly Kepler and TESS, are highlighted, including planet occurrence rates, multi-planet system architectures, and the discovery of the planetary “radius valley,” which provides evidence for atmospheric mass-loss processes in small planets. The role of transit timing variations and joint analyses with radial-velocity data in constraining planetary masses and bulk compositions is also examined. Current limitations, notably stellar activity and observational biases, are critically assessed. Transit photometry will remain central to exoplanet discovery and atmospheric studies in the era of next-generation observatories.
Copyright (c) 2026 Jude Oruaode Vwavware, Mu’allim Yakubu, Austin Okechukwu Ojobeagu, Adrian Ohwofosirai https://creativecommons.org/licenses/by-nc/4.0
Assessment of Groundwater Potential and Vulnerability in Gurku-Gwari and Environs North-Central Nigeria, Using Electrical Resistivity Method
Obtaining useful information regarding groundwater potential and vulnerability is essential for deciding whether groundwater can be used for drinking and for other purposes. Water remain one of the vital elements for sustaining any growing population; therefore, this research work is carried out around Gurku-Gwari community, Karu local government area, Nasarawa state, Nigeria; with the aim of evaluating groundwater potential and its vulnerability using vertical electrical sounding (VES) method. A total of fifteen (15) VES locations were surveyed using Omega 2.0 resistivity meter to measure subsurface resistivity variations. The acquired data were processed using WinRESIST 2.0 to determine layers apparent resistivity, thicknesses and to delineate geo-electric layers. Surfer 13, Geosoft, and ArcGIS 10.7.1 softwares were utilized for contouring and map production respectively. The interpreted field curves shows three to four geo-electric layers with model resistivity value ranging from 14.9 Ωm to 51,202.7 Ωm and thickness between 0.8 m to 20.6 m with a maximum depth to fresh basement of about 35.5 m. The aquifer units across the study area occurred predominantly within the weathered/fractured basement. Results of Dar-Zarrouk analysis revealed a longitudinal conductance values ranging from 0.0012 m/Ωm to 0.0436 m/Ωm, transverse resistance variation of 532.35 Ωm2 to 11538.04 Ωm², hydraulic conductivity values of 1.0651 m/day to 9.9210 m/day and transmissivity values ranging from 7.79 m2/day to 139.4 m2/day. These results suggest that the study area has poor protective capacity which makes the area vulnerable to contamination and the aquifer potential yield is low to moderate. Based on these findings, the most favourable locations for borehole drilling are VES 4 south of Gurku-Gwari settlement and VES 6 and 12 south-west and north-west of Kubobbagi settlement respectively.
Copyright (c) 2025 Zakariya Samuel Varah, Jonathan Barka, Abubakar B. Danjuma https://creativecommons.org/licenses/by-nc/4.0
Assessment of Climate Variability and Associated Health Implications under Cyclonic and Anticyclonic Atmospheric Conditions in Ado-Ekiti, Southwestern Nigeria
Atmospheric circulation systems play a crucial role in regulating rainfall occurrence and environmental conditions within tropical upland regions. This study examines climate variability and associated health implications under cyclonic and anticyclonic atmospheric conditions in Ado-Ekiti, Southwestern Nigeria. Meteorological parameters comprising atmospheric temperature, ambient temperature, wind speed, and precipitation probability were obtained from the Meteoblue database and analysed using descriptive time-series techniques. The results indicate a pronounced diurnal cycle characterized by progressive warming from morning to afternoon hours followed by gradual cooling during the evening. Rainfall probability exhibited a delayed response relative to peak temperature conditions, reaching maximum values during the late afternoon and evening periods. Wind speed showed moderate variability throughout the observation period and remained within a relatively stable range. The findings suggest that precipitation occurrence in the study area is primarily controlled by local thermodynamic processes, moisture availability, and topographic influences rather than strong synoptic-scale disturbances. The observed climatic behaviour has important implications for flood susceptibility, water-resource management, thermal stress exposure, and the transmission of climate-sensitive diseases. The study provides insight into the atmospheric mechanisms governing rainfall variability in upland environments and highlights the importance of integrating meteorological information into environmental planning and public-health adaptation strategies.
Copyright (c) 2025 Olumuyiwa Ademola Alao, Kazeem Adeleke Musiliyu, Isaac Rotimi Ajayi, Daniel Boniface Akpan, Joseph Aderemi Adebanji https://creativecommons.org/licenses/by-nc/4.0
Structural and Electrochemical Properties of Graphene Oxide Nanoparticles Synthesized via Modified Hummers Method for Energy Storage Electrodes
Graphene Oxide (GO) nanoparticles of high quality were synthesized using the improved modified Hummers method. Their morphological and structural properties were thoroughly investigated. SEM analysis revealed flake-like, irregular layered fragments typical of GO sheets, with a rough and uneven surface texture resulting from exfoliation and oxidation. XRD analysis showed a distinct peak at ~9.2°, corresponding to the (001) diffraction plane of GO, indicative of increased interlayer spacing due to oxygen functional groups and intercalated water molecules formed during graphite oxidation. The calculated particle size was 10.96 nm with a strain value of 0.1767, determined using the Williamson–Hall equation. BET analysis indicated a specific surface area of 255.66 m²/g and a pore size distribution of 2.137 nm. FT-IR spectra confirmed the presence of oxygen-containing functional groups (hydroxyl, epoxy, and carboxyl), which impart hydrophilicity and chemical reactivity, making GO suitable for composites, membranes, and biomedical applications. Electrochemical evaluation demonstrated favorable performance, with an energy density of 6.54 Wh/kg and a power density of 40.16 kW/kg. EIS analysis further revealed an electrochemical series resistance (ESR) of 13.8 Ω and a charge transfer resistance (Rct) of 107.38 Ω, underscoring the material’s potential for energy storage applications
Copyright (c) 2025 Okike Okorie, Medina Umar, Abdul Dahiru Ardo Buba https://creativecommons.org/licenses/by-nc/4.0
Unsupervised Dimensionality Reduction and Noise Suppression in Marine Gravity Data in Oron-Calabar Waterway, Southern Nigeria
Marine gravity data acquired along the Oron-Calabar waterway, southern Nigeria, a sedimentary-dominated and structurally complex sector of the Gulf of Guinea, are often affected by high-frequency noise and signal superposition, limiting the resolution of basement architecture required for basin analysis. This study applies an unsupervised machine-learning framework for dimensionality reduction and noise suppression to enhance the Free-Air Gravity Anomaly (FAGA) field derived from marine gravimeter measurements. The observed gravity measurement ranged from 978,000 to 978,380mGal. Both Linear and nonlinear dimensionality reduction techniques were evaluated, and the results show that a Convolutional Autoencoder, compressing the gravity data into a 12-dimensional latent space, provided the most effective enhancement by reducing high-frequency noise amplitude by 42% and improving the signal-to-noise ratio by 8.5dB. The enhanced gravity field significantly improved structural resolution, allowing clearer identification of residual anomalies ranging from −13 to +13mGal associated with a buried igneous ridge and a more sharply defined intra-basin fault, where gravity gradients increased from 8.3 to 13.7mGal after processing. Interpretation of the dominant latent components indicates that they capture regional long-wavelength gravity trends (−8 to +5mGal) linked to crustal thinning, superimposed localized high-amplitude anomalies (+15 to +30mGal) related to intrusive basement bodies, and intermediate-wavelength signals (−10 to +8mGal) corresponding to sedimentary depocenters. These results demonstrate that machine-learning-based dimensionality reduction provides a robust and objective approach for enhancing noisy marine gravity data and improving tectonic interpretation and resource assessment within the Oron–Calabar coastal corridor.
Copyright (c) 2025 Udoh Felix Evans, Idara Okon Akpabio, Mfon David Umoh, Emmanuel Asuquo Ating https://creativecommons.org/licenses/by-nc/4.0
Statistical Analysis and Radiological Assessment of Radon-222 Concentrations in Borehole Water from Giade, Bauchi State, Nigeria
Radon-222 (²²²Rn) is a naturally occurring radioactive gas that poses potential health risks through ingestion and inhalation when dissolved in drinking water. This study presents the first comprehensive assessment of ²²²Rn concentrations in 10 borehole water samples from Giade Local Government Area, Bauchi State, Nigeria. Samples were analyzed using a Tri-Carb Liquid Scintillation Analyzer 1000 at the Centre for Energy Research and Training, Ahmadu Bello University, Zaria. Measured ²²²Rn concentrations ranged from 0.346 to 6.930 Bq/L, with a mean of 3.401 ± 2.128 Bq/L. Descriptive and inferential statistical analyses (including normality tests, correlations with physicochemical parameters) were performed. Radiological risk assessment showed annual effective doses well below the WHO reference level of 0.1 mSv/y for all age groups. Excess lifetime cancer risk (ELCR) values were negligible. The results indicate that borehole water in Giade is radiologically safe for consumption, though continuous monitoring is recommended due to geological variability in the region.
Copyright (c) 2026 Umar Wadata, Emmanuel Joseph, Adamu N. Baba-Kutigi https://creativecommons.org/licenses/by-nc/4.0
Construction of Polyvinyl Alcohol (PVAL)-Based Breast Phantoms with Simulated Calcifications and Evaluation of the Effect of Breast Thickness on Radiation Dose in Full Field Digital Mammography
The aim of the present study is to fabricate tissue equivalent breast phantoms with embedded calcification, to investigate their mean glandular dose (MGD) and entrance surface dose (ESD) at various thicknesses using Full Field Digital Mammography (FFDM). Four breast phantoms with embedded calcifications were fabricated using different 10% polyvinyl alcohol (PVAL)-based composites. The first three phantoms were composed of 10% PVAL + ethanol, 10% PVAL, and 10% PVAL + graphite powder, designed to simulate BI-RADS breast density categories 2, 3, and 4, respectively. The fourth phantom was a heterogeneous model constructed by combining the three composite materials in varying proportions. A total of 32 mammographic scans were carried out using AEC (automatic exposure control) mode at different compression force. All exposure parameters were recorded including the applied compression force, MGD and ESD. The study revealed that the compressed phantom thickness (CPT) of all the phantoms investigated ranged from 2.7 to 5.2 cm, MGD ranged from 1.58 – 3.29 mGy (mean = 2.36 ± 0.07) and ESD ranged from 3.7 – 12.33 mGy (mean = 7.10 ± 0.36). The MGD and ESD showed a positive correlation with CPT with r (30) = 0.72, P < 0.0000038 and r (30) = 0.91, P < 0.000001 respectively. The results of the present study are similar to published values, the MGD and ESD are also within the acceptable dose limit recommended by ACR protocol.
Copyright (c) 2025 Franca Oyiwoja Okoh, Norlaili Ahmad Kabir, John Actor Ocheje, Moses Ejike Onudibia, Mohd Fahmi Mohd Yusof, Siti Nor Azizah Abdullah https://creativecommons.org/licenses/by-nc/4.0
Cutoff Effects on the Equation of State of a Lennard–Jones Fluid: A Statistical Mechanical Analysis
The Lennard–Jones (LJ) fluid is a standard model for linking microscopic intermolecular interactions to macroscopic thermodynamic behavior, yet its Molecular Dynamics (MD) predictions remain sensitive to potential truncation. This study uses equilibrium MD simulations to determine the equation of state (EOS) of a three-dimensional LJ fluid across reduced densities and temperatures. Pressure, potential energy, and compressibility factor were computed using the virial formulation, with emphasis on how cutoff radius and analytical tail corrections affect thermodynamic accuracy. The simulations reproduced expected LJ-fluid behavior: pressure increased nonlinearly with density, while the compressibility factor showed a transition from attraction-dominated states (Z<1) <!-- [if gte msEquation 12]><m:oMath><m:r>(</m:r><m:r>Z</m:r><m:r><1)</m:r></m:oMath><![endif]--> <span lang="EN-US" style="font-size: 11.0pt; line-height: 107%; font-family: 'Calibri',sans-serif; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: Calibri; mso-fareast-theme-font: minor-latin; mso-hansi-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-theme-font: minor-bidi; position: relative; top: 3.0pt; mso-text-raise: -3.0pt; mso-font-kerning: 0pt; mso-ligatures: none; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;"> to repulsion-dominated states (Z>1). Comparing rc=2.0σ, 2.5σ<!-- [if gte msEquation 12]><m:oMath><m:sSub><m:sSubPr><m:ctrlPr></m:ctrlPr></m:sSubPr><m:e><m:r>r</m:r></m:e><m:sub><m:r>c</m:r></m:sub></m:sSub><m:r>=2.0</m:r><m:r>σ</m:r><m:r>, 2.5</m:r><m:r>σ</m:r></m:oMath><![endif]--> , and <!-- [if gte msEquation 12]><m:oMath><m:r>3.0</m:r><m:r>σ</m:r></m:oMath><![endif]--> <span lang="EN-US" style="font-size: 11.0pt; line-height: 107%; font-family: 'Calibri',sans-serif; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: Calibri; mso-fareast-theme-font: minor-latin; mso-hansi-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-theme-font: minor-bidi; position: relative; top: 3.0pt; mso-text-raise: -3.0pt; mso-font-kerning: 0pt; mso-ligatures: none; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;"> 3.0σ revealed systematic truncation errors that increased with density. At T = 1.2 and ρ = 0.8, pressure deviations between the smallest and largest cutoffs reached about 6–10%, while potential-energy deviations exceeded 10%. Tail corrections substantially reduced these errors and improved agreement with larger-cutoff simulations, although residual deviations persisted in dense, strongly correlated states. The findings show that cutoff treatment is a state-dependent thermodynamic bias in EOS reconstruction, not merely a computational setting.
Copyright (c) 2026 Isaiah Eze Igwe, Moses A. Tyav https://creativecommons.org/licenses/by-nc/4.0
Radiological Assessment and Potential Health Implication of Produced Water from Oil facilities Around Oil Mining Lease (OML X), Southern Delta, Nigeria
This study assessed the concentration of naturally occurring radionuclides in produced water from Oil Mining Lease (OML X) and evaluated their potential health implications in the Niger Delta, Nigeria. The totality of produced water collected for measurement were eighteen (18), three from each oil-field facility and analyzed using Gamma-Ray Spectrometer (sodium iodide (NaI(Tl)) . the obtained mean values of 40K, 238U and 232Th are 122.14 BqL⁻¹, 10.58 BqL⁻¹ and 4.12 BqL⁻¹ respectively. The mean computed potential radiological health implications parameters of Raeq, DR, AEDEout, AEDEin, Hex, Hin and Iy are 25.87 BqL⁻¹, 12.47 nGy/h, 0.0153 mSv/y, 0.0612 mSv/y, 0.0699, 0.0985 and 0.0965 respectively. However, the obtained values of radionuclides exceeded the world recommended limits while that of computed potential radiological are below world recommended limits. Therefore, the values may not pose significant radiological health impact as at the time of the research, but it may have potential long-term impact with time. Hence, release oil-field facility produced water ought to be treated appropriately before discharged into the environment. All hydrocarbon operation stakeholders should carry out routine monitoring of the study area environment. This research also provides critical baseline data for environmental radiation management and supports policy development toward sustainable oil production and public health protection in the Niger Delta region.
Copyright (c) 2025 Oghenevovwero Emmanuel Esi, O. Samuel Marere, O. Alex Teghware, Destiny Orute, O. Ezekiel Agbalagba https://creativecommons.org/licenses/by-nc/4.0
Assessing the Impact of Anthropogenic Stressors on Ecosystem Dynamics in the Niger Delta Coastal Area, Nigeria
Anthropogenic stressors, particularly oil pollution, forest fires, and urbanization, are major drivers of ecosystem degradation in the Niger Delta coastal region of Nigeria. This study assessed their impacts on vegetation health by integrating oil spill records from the National Oil Spill Detection and Response Agency (NOSDRA) with Sentinel-2 MSI Level-2A imagery. Vegetation condition and disturbance were evaluated using the Normalized Difference Vegetation Index (NDVI), Normalized Burn Ratio (NBR), and Normalized Difference Building Index (NDBI), alongside biophysical variables including Leaf Area Index (LAI), Leaf Chlorophyll Content (LCC), Fraction of Vegetation Cover (FCOVER), and Fraction of Absorbed Photosynthetically Active Radiation (FAPAR). Maximum Likelihood Supervised Classification (MLSC) was applied to map land cover and quantify its spatial distribution. Results revealed that oil spills, predominantly caused by sabotage (85%), substantially reduced vegetation greenness, density, and productivity. Fire outbreaks associated with illegal refining further intensified vegetation loss and landscape degradation. Land cover analysis showed that grasslands occupied 33% of the study area, canopy vegetation 30%, non-vegetated and burned land 21%, built-up areas 12%, and freshwater bodies 5%. The integration of Sentinel-2 imagery, biophysical variables, and oil spill records provided a robust framework for monitoring the cumulative effects of multiple anthropogenic stressors on ecosystem dynamics. The findings underscore the need for strengthened environmental governance, sustainable vegetation management, and improved oil spill prevention strategies to enhance ecosystem resilience and support environmental restoration in the Niger Delta.
Copyright (c) 2026 Mujidat Titilope Taofeek, Leke Sunday Adebiyi https://creativecommons.org/licenses/by-nc/4.0
Assessment of Aquifer Protective Capacity and Groundwater Vulnerability Using VES-Derived Longitudinal Conductance in Iwo, Southwestern Nigeria
Investigation of groundwater vulnerability is indispensable for sustainable aquifer management, principally in areas experiencing rapid population growth and increasing anthropogenic pressure on water resources. This study employs the vertical electrical sounding (VES) method to investigate aquifer protective capacity using longitudinal conductance, a geoelectrical parameter that serves as a quantitative indicator of groundwater vulnerability investigation. In this study, six VES stations were acquired across the study area and interpreted using one-dimensional layered-earth inversion to determine subsurface resistivity distribution and the thickness of overlying lithologic units. The longitudinal conductance (S) was calculated as the sum of the ratios of layer thickness to resistivity for all layers. The results revealed that the overburden thickness ranges from 3.8 to 35.1 m, the bedrock resistivity ranges from 545.3 to 3353.4 Ωm, and the calculated longitudinal conductance values vary from (0.13345 to 0.250887 S), indicating principally weak to moderate protective capacity, which suggest varying degree of groundwater vulnerability across the investigated VES stations. The results showed that in terms of aquifer vulnerability, low values suggest more vulnerability to surface contamination, whereas higher longitudinal conductance and thicker overburden suggest enhanced protective capacity. Therefore, the study emphasized that the VES-derived longitudinal conductance offers a vital background data for groundwater protection and management; however, they represent a preliminary vulnerability assessment.
Copyright (c) 2025 Adetunji Adeniji, Ajani Olumide, Kolawole Tolulope https://creativecommons.org/licenses/by-nc/4.0
Evaluation of CNTFETs Temperatures and their Performance using High-K Gate Dielectrics to Enhance Nanoelectronic Applications
High-k dielectrics combined with CNTFETs are potential alternative to next-generation nanoelectronics devices when the traditional silicon-based devices are nearing a scaling limit due to increasing leakage current and power dissipation. The performance of Carbon Nanotube Field Effect Transistors (CNTFETs) is examined in this work in relation to temperature change and high-k dielectric constants (high-k gate materials). This paper employed the cylindrical CNTFET model as a tool to examine six dielectric materials, namely SiO2, Al2O3, Y2O3, Ta2O5, HfO2 and La2O3 at wide temperature range of 300K to 1000K. The key performance parameters that are investigated, include ON current, OFF current, subthreshold swing (SS), drain induced barrier lowering (DIBL), transconductance (gm), output conductance (gd), voltage gain (AV), and carrier injunction velocity (Vinj). The results show that increasing dielectric constant enhances the ON current, transconductance, and carrier injection velocity due to an improved gate capacitance and a stronger electrostatic control. On the other hand, higher temperatures cause subthreshold swing to deteriorate and OFF current to increase, showing decreased switching efficiency under high thermal circumstances. At 1000K, La2O3 outperformed lower-k materials in terms of drive current (7.775e-05A) and carrier transport (6.042e+05m/s). The research also indicates that temperature affects significantly short-channel effects such as DIBL and leakage behavior. As much as the thermal effects need to be put under control to achieve maximum reliable and efficient devices, the integration of high-k dielectrics and CNTFET architectures have immense potential in providing high-performance and low-power applications.
Carbon Nanotube Field Effect Transistors (CNTFETs)
Copyright (c) 2025 Maryam Ibrahim, Garba Shehu M. Galadanci https://creativecommons.org/licenses/by-nc/4.0
Strategies for Improving Access and Effectiveness of CT and MRI Imaging Modalities in Low-Middle-Income Countries: A Review
Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) have been gaining global attention in diagnosing non-communicable diseases and improving clinical outcomes. However, significant disparities have been observed in these imaging modalities caused by a lack of or limited access to these devices, financial constraints, infrastructure, and workforce limitations. This review, therefore, examines strategies to improve access and effectiveness of CT and MRI in low- and middle-income countries (LMICs). A scoping review methodology was adopted, involving searches of major databases including PubMed, Scopus, Web of Science, and grey literature, with thematic synthesis used to categorize barriers and proposed solutions. The findings of this study reveal multifaceted challenges across technology, facility, health-system, and patient levels. High acquisition and maintenance costs, unreliable power supply, shortage of trained personnel, weak regulatory frameworks, and inadequate health information systems were identified as key barriers. These factors contribute to equipment downtime, low utilization, long waiting times, and catastrophic out-of-pocket expenditures for patients. Strategic recommendations emphasize innovative financing models, procurement of ruggedized and portable imaging technologies, workforce training, strengthened policy frameworks, improved data systems, and community-level interventions such as mobile imaging services. In conclusion, coordinated multi-level actions are required to break the cycle of under-provision and under-utilization. The study recommends national diagnostic imaging plans, increased funding, regulatory reforms, and expansion of affordable, decentralized imaging services to promote equitable access and improved health outcomes in LMICs.
Copyright (c) 2025 Emmanuel Abiodun Oni, Oluwaseun O. Oyelayo, Michael Oluwatobi Adegunlola, Abraham Aremu Adewale, Oluwaseun Olaitan Oloyede, Zaccheaus Bamise James, Victoria Mathew, Olalere Timothy Orodiran, Paul Shola Ayanlola https://creativecommons.org/licenses/by-nc/4.0
Assessment and Optimization of Paediatric Radiation Dose in Computed Tomography
The main aim of this study is to assess and enhance the effectiveness of radiation dose optimization techniques in pediatric CT scanning to ensure diagnostic quality while minimizing patient risk. Analyzing and reviewing past scans and employing scan statistics, it focuses on key dose metrics like volume computed tomography (CTDIvol). and dose length product (DLP). Radiology staff were interviewed to evaluate their understanding of dose – reduction protocols and their use of relevant technologies, such as minimizing tube current, minimizing tube potential, minimizing scan length Automatic Exposure Control, (AEC), iterative Reconstruction (IR), and artificial intelligence (AI). A study revealed significant variation in how CT scan is performed on children. While technologies like Automatic Exposure Control (AEC) and Iterative Reconstruction (IR) can reduce excess radiation, inconsistent staff training and equipment make it difficult to standardize safe radiation doses. Organized efforts for standardization have been spearheaded by professional societies such as the American Association of Physicists in guidelines, enhancing technologist training, and investing in new technology to develop safer radiological practices for children.
Copyright (c) 2026 Kabir Jamaladdeen, Muhammad Bashir Gide https://creativecommons.org/licenses/by-nc/4.0
First-Principles Investigation of Structural Stability and Optoelectronic Properties of Lead-Free CsSnₓGe₁₋ₓI₃ Mixed-Halide Perovskites for Advanced Optoelectronic Applications
The escalating demand for sustainable energy solutions necessitates the development of high performance, environmentally benign photovoltaic materials. Lead-halide perovskites, while highly efficient, present significant toxicity concerns, driving intensive research into lead-free alternatives. This study employs first-principles density functional theory (DFT) to comprehensively investigate the thermodynamic stability, phase behavior, and optoelectronic characteristics of the mixed-cation lead-free perovskite series, CsSnₓGe₁₋ₓI₃. Our objective was to elucidate the fundamental properties governing their suitability for next-generation solar cells and optoelectronic devices. Key findings reveal that the solid solutions of CsSnₓGe₁₋ₓI₃ exhibit enhanced thermodynamic favourability and stability compared to their single-metal counterparts, highlighting the critical role of compositional engineering. Specifically, CsSn₀.₅Ge₀.₅I₃ demonstrates optimal thermodynamic stability, underscoring the beneficial impact of tin incorporation. Electronic structure analysis indicates a tunable direct electronic bandgap, ranging from 1.331 eV for CsSnI₃ to 1.927 eV for CsGeI₃, with a linear compositional dependence, making these materials highly adaptable for various spectral absorptions. A notable phase transition and subsequent phase segregation are observed when tin doping exceeds x = 0.53, leading to compositions such as CsSn₁/₃Ge₂/₃I₃ and CsSn₀.₇₅Ge₀.₂₅I₃, which possess favorable bandgaps and high absorption coefficients. Furthermore, detailed evaluation of optical properties, including the complex refractive index and absorption coefficient, confirms exceptional light-harvesting potential across the visible and near-infrared regions. These theoretical insights provide a robust foundation for the rational design and synthesis of stable, efficient, and eco-friendly halide perovskites. The demonstrated tunability of optoelectronic properties and intrinsic thermodynamic stability positions CsSnₓGe₁₋ₓI₃ as a promising candidate for advanced photovoltaic and light-emitting diode applications, thereby contributing significantly to the advancement of sustainable nanotechnology in energy conversion.
Copyright (c) 2026 Samuel Adebayo, Ajide Adeolu Bamidele, Mojoyinola Kofoworola Awodele, Ayodeji Oladiran Awodugba https://creativecommons.org/licenses/by-nc/4.0
A Study of the Quantitative Assessment of Radiation Dose Out Put for Tomography View of the Dental Cone Beam Computed Tomography (CBCT) System
The efficiency of machine operation in radiology has been established to be affected by many factors, such as the device used, and the exposure level adopted for a specific type of radiation. The radiation exposure from cone beam computed tomography (CBCT) system is generally higher than that of other diagnostic modalities such as X-ray and computed tomography (CT) scan. This study aims to determine patient dosimetry on CBCT scanners used in Advanced Medical and Dental Institute (AMDI) University Sains Malaysia (USM). The CTDI phantom was scanned using the common exposure settings used in clinical routine (90 kVp, 8 mA) with a full rotation scan. For the standard CTDI method, the dosimeter was placed to measure the doses at the central hole (CTDIc) and the four peripheral holes (CTDIp) of the phantom making a total of five measurement points in the scanning field of view. The percent deviation of the recorded doses at the peripheral points were observed to range from 0.7 % to 10 %. The highest average dose was observed at the hole C which is about 90° and with a position near the x-ray tube. Furthermore, the measured <!-- [if gte msEquation 12]><m:oMath><m:sSub><m:sSubPr><m:ctrlPr></m:ctrlPr></m:sSubPr><m:e><m:r>CTDI</m:r></m:e><m:sub><m:r>100</m:r></m:sub></m:sSub></m:oMath><![endif]--> <span lang="EN-US" style="font-size: 11.0pt; line-height: 107%; font-family: 'Calibri',sans-serif; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: Calibri; mso-fareast-theme-font: minor-latin; mso-hansi-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-theme-font: minor-bidi; position: relative; top: 3.0pt; mso-text-raise: -3.0pt; mso-font-kerning: 0pt; mso-ligatures: none; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;"> value was 3.286 mGy which was within the expected range of (<!-- [if gte msEquation 12]><m:oMath><m:r>40 </m:r><m:r>mGy</m:r><m:r>)</m:r></m:oMath><![endif]--> <span lang="EN-US" style="font-size: 11.0pt; line-height: 107%; font-family: 'Calibri',sans-serif; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: Calibri; mso-fareast-theme-font: minor-latin; mso-hansi-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-theme-font: minor-bidi; position: relative; top: 3.0pt; mso-text-raise: -3.0pt; mso-font-kerning: 0pt; mso-ligatures: none; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;"> which is the value obtainable in most standard scanning protocols. The difference between the displayed and measured CTDIvol value was 0.814 (19.85 %) which was observed to be within 20 %, which is comparable to that of the Swiss legal requirements (within a <!-- [if gte msEquation 12]><m:oMath><m:r>±</m:r></m:oMath><![endif]--> <span lang="EN-US" style="font-size: 11.0pt; line-height: 107%; font-family: 'Calibri',sans-serif; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: Calibri; mso-fareast-theme-font: minor-latin; mso-hansi-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-theme-font: minor-bidi; position: relative; top: 3.0pt; mso-text-raise: -3.0pt; mso-font-kerning: 0pt; mso-ligatures: none; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;"> 20 % threshold limit) and the American Association of Physicist in Medicine (AAPM) report 204 of approximately 20%. This study showed the effectiveness of CTDI as a dose index in CBCT scans and also that the CBCT scanner in AMDI USM poses no risk to the patients.
Copyright (c) 2026 James Anthony Rabba, Noor Diyana Osman, Hanis Arina Jaafar, Mohd Zubir Mat Jafri, Fatanah Mohamad Suhaimi, Felix Omachoko Uloko https://creativecommons.org/licenses/by-nc/4.0
Exploring Ground State Energies and Electronic Band Structures of Bi₂Se₃ and Bi₂Te₃ Topological Insulators: A First-Principles DFT Approach for Spintronic and Thermoelectric Applications
Topological insulators (TIs) such as Bismuth selenide (Bi₂Se₃) and Bismuth Telluride (Bi₂Te₃) have attracted attention for their unique electronic properties, featuring insulating interiors and conducting surface states protected by time-reversal symmetry. This study uses Density Functional Theory (DFT) to investigate the ground state energies and electronic band structures of these TIs. The calculated ground state energies for Bi₂Se₃ and Bi₂Te₃ are -675,251.44 eV and -796,226.99 eV, aligning closely with experimental data. These results confirm the stability of the materials and their characteristic band gaps and robust surface states. Spin-orbit coupling (SOC) is essential in inducing band inversion at the Γ point, a key feature of TIs. Additionally, the high density of states near the Fermi level in Bi₂Te₃ suggests potential thermoelectric applications. These findings highlight the relevance of Bi₂Se₃ and Bi₂Te₃ in spintronics and quantum computing.
Copyright (c) 2026 Francis Aungwa, Emmanuel J. Adoyi, Paul E. Akpowaide https://creativecommons.org/licenses/by-nc/4.0
Geoelectrical Assessment of Groundwater Potential and Aquifer Protective Capacity Using Vertical Electrical Sounding in Osin-Ekiti, Southwestern Nigeria
Adequate supply of potable water is needed for domestic and agricultural uses, and groundwater is a significant source of fresh water that needs to be protected to safeguard its future sustainability. This study utilized the geoelectrical parameters obtained from Vertical Electrical Sounding (VES) to assess groundwater potential and protective capacity of aquifers in parts of Osin-Ekiti, Southwest Nigeria. Sixteen (16) VES points were occupied using the Schlumberger electrode array, with current electrode separation (AB/2) between 1 and 100 m. The geoelectric interpretation identified three to six subsurface layers, comprising topsoil, clay, weathered layer, partly weathered layer, and fresh basement. The resistivity data were interpreted to produce isopach, isoresistivity, and Dar-Zarrouk parameter maps, including longitudinal conductance (S), and transverse resistance (T). Results show that overburden thickness ranges between 1 and 29.1 m, while resistivity values vary from <100 to >19,000 Ωm. The longitudinal conductance values (0.0001–1.6 S) classify the aquifer protective capacity from highly protected to poorly protected, whereas transverse resistance values (<100 to >3000 Ωm²) reveal low to high groundwater potential. The north-central and parts of the central region of the study area exhibit the most favorable conditions with T > 500 Ωm², S ≥ 0.1 S, and appreciable overburden thickness (> 12 m) that indicates a combination of adequate groundwater storage, moderate to high transmissivity, and fair to high aquifer protective capacity.
Copyright (c) 2026 Gbenga Olakunle Ogungbesan, Olayiwola Grace Olaseeni, Jacob Tsado, Iyanu Ayokanmi David, Anuoluwa Olamide Olatunji, Tokunbo Sanmi Fagbemigun https://creativecommons.org/licenses/by-nc/4.0
Radiological Risk Assessment of Roasted Food Processing Activities and Implications for Sustainable Public Health in Ondo State, Nigeria
Roasted food vending is a widespread informal economic activity in Southwestern Nigeria, where biomass fuels such as charcoal and firewood are commonly used for food preparation. This study assessed the radiological hazards associated with ionizing radiation exposure around selected roasted food vending sites in Ondo State, Southwestern Nigeria, with emphasis on environmental sustainability and public health implications. Background ionizing radiation measurements were conducted around twenty-one (21) randomly selected roasted food vendors located in Okitipupa (OK), Ode-Irele (IR), and Ore (OR) during roasting and non-roasting periods using a digital GQ-500 Geiger–Müller counter positioned at 1 m above ground level. Absorbed dose rate (Ḋ), annual effective dose (Ė), and excess lifetime cancer risk (ELCR) were evaluated from the measured exposure rates, while descriptive and inferential statistical analyses were employed. Mean exposure rates during non-roasting periods ranged from 0.006 to 0.007 mRh⁻¹, whereas significantly higher values of 0.017 to 0.020 mRh⁻¹ were recorded during roasting periods. The maximum absorbed dose rate during roasting was 234.9 nGy h⁻¹, exceeding the global average background value of 59 nGy h⁻¹ and the recommended public limit of 84 nGy h⁻¹. Statistical analysis revealed a significant increase in radiation exposure during roasting activities (p < 0.05), with approximately 186% higher levels than during non-roasting periods. Although annual effective dose and ELCR values remained below internationally recommended limits, the findings indicate that combustion-related roasting activities contribute to localized increases in environmental radiation levels. The study highlights the need for environmental radiation monitoring, cleaner fuel adoption, improved ventilation, and occupational safety practices to promote sustainable public health and environmental protection.
Copyright (c) 2026 Olusegun Yemi Omogunloye, Abiola Olawale Ilori, Temitope Isaiah Ojo, Iwamisan Mark Adewumi https://creativecommons.org/licenses/by-nc/4.0
Concentrations, Source Apportionment, and Non-Carcinogenic/Carcinogenic Health Risk Assessment of Heavy Metals in Classroom Settled Dust at Federal University Wukari, Taraba State, Nigeria
The presence of heavy metals in our environment is a persistent threat to our health. These toxic substances can accumulate in our bodies and cause serious harm, especially when we're exposed to them over a long period. This study investigated the concentrations of lead (Pb), cadmium (Cd), and chromium (Cr) in settled dust from ten classrooms (lecture theatres, science laboratories, and multipurpose halls) at Federal University Wukari, Taraba State, Nigeria. Dust samples were collected from floors, desks, and windowsills, sieved to particles <100 µm, and analysed using flame atomic absorption spectrophotometry (FAAS). Health risk assessment was conducted for adult and child receptors via ingestion, inhalation, and dermal contact pathways, following USEPA (2001) guidelines. Mean concentrations were Pb = 0.331 ± 0.204 mg/kg, Cd = 0.0102 ± 0.0118 mg/kg, and Cr = 0.0013 ± 0.0005 mg/kg, with multipurpose halls recording the highest levels (Pb: 0.741 mg/kg; Cd: 0.0421 mg/kg). Ingestion was the dominant exposure pathway, contributing >85% of total exposure. Non-carcinogenic hazard quotients (HQ) for all metals and pathways were <<1 (mean HQ of_Pb = 8.38 × 10⁻⁵ for adults; 7.82 × 10⁻⁴ for children), indicating no significant non-carcinogenic health risks. Cancer risks were below the USEPA acceptable range (10⁻⁶–10⁻⁴), with total risks of 2.94 × 10⁻⁹ (adults) and 5.99 × 10⁻⁹ (children). Principal contamination sources include vehicular emissions, generator exhaust, deteriorating building materials, laboratory activities, soil resuspension, and atmospheric deposition. While risks are currently low, proactive management is recommended to prevent future accumulation.
Copyright (c) 2026 John Actor Ocheje, Maxwell Ayuk https://creativecommons.org/licenses/by-nc/4.0
Radiological Impact Assessment of Radon Levels in Drinking Water and its Associated Health Risks in Aniocha North, Delta State, Nigeria
Groundwater is a major source of natural water for domestic, industrial and agricultural use; however, its contamination by 222Rn has become a major source of human health concern globally. To assess the associated health risks of radon exposure to various age groups within Aniocha North Local Government Area (LGA) of Delta State, Nigeria, twenty water samples from 12 surface reservoirs and eight boreholes were collected from five communities within the local government and analyzed using RAD7. The measured concentrations of 222Rn in the sampled water, ranges from 0.278 <!-- [if gte msEquation 12]><m:oMath><m:r>Bq</m:r><m:r>/</m:r><m:r>L</m:r></m:oMath><![endif]--> <span lang="EN-US" style="font-size: 11.0pt; line-height: 107%; font-family: 'Calibri',sans-serif; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: Calibri; mso-fareast-theme-font: minor-latin; mso-hansi-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-theme-font: minor-bidi; position: relative; top: 3.0pt; mso-text-raise: -3.0pt; mso-font-kerning: 0pt; mso-ligatures: none; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;"> in OBIOR 5 to 9.281 <!-- [if gte msEquation 12]><m:oMath><m:r>Bq</m:r><m:r>/</m:r><m:r>L</m:r></m:oMath><![endif]--> <span lang="EN-US" style="font-size: 11.0pt; line-height: 107%; font-family: 'Calibri',sans-serif; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: Calibri; mso-fareast-theme-font: minor-latin; mso-hansi-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-theme-font: minor-bidi; position: relative; top: 3.0pt; mso-text-raise: -3.0pt; mso-font-kerning: 0pt; mso-ligatures: none; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;"> in ISSELE-AZAGBA 3 with mean concentration of 3.808<!-- [if gte msEquation 12]><m:oMath><m:r>Bq</m:r><m:r>/</m:r><m:r>L</m:r></m:oMath><![endif]--> <span lang="EN-US" style="font-size: 11.0pt; line-height: 107%; font-family: 'Calibri',sans-serif; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: Calibri; mso-fareast-theme-font: minor-latin; mso-hansi-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-theme-font: minor-bidi; position: relative; top: 3.0pt; mso-text-raise: -3.0pt; mso-font-kerning: 0pt; mso-ligatures: none; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;"> , found to be lower than the recommended threshold by the United States Environmental Protection Agency. The estimated radiological indices revealed that the average annual effective doses due to ingestion of radon are 8.82714×10-6, 3.9998×10-6, and 2.79296×10-6<!-- [if gte msEquation 12]><m:oMath><m:r>(</m:r><m:r>μSv</m:r><m:r>/</m:r><m:r>y</m:r><m:r>)</m:r></m:oMath><![endif]--> <span lang="EN-US" style="font-size: 11.0pt; line-height: 107%; font-family: 'Calibri',sans-serif; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: Calibri; mso-fareast-theme-font: minor-latin; mso-hansi-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-theme-font: minor-bidi; position: relative; top: 3.0pt; mso-text-raise: -3.0pt; mso-font-kerning: 0pt; mso-ligatures: none; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;"> for adults, children and infants respectively. Inhalation dose ranged from 0.0004158 to 0.02338812 <!-- [if gte msEquation 12]><m:oMath><m:r>(</m:r><m:r>μSv</m:r><m:r>/</m:r><m:r>y</m:r><m:r>)</m:r></m:oMath><![endif]--> <span lang="EN-US" style="font-size: 11.0pt; line-height: 107%; font-family: 'Calibri',sans-serif; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: Calibri; mso-fareast-theme-font: minor-latin; mso-hansi-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-theme-font: minor-bidi; position: relative; top: 3.0pt; mso-text-raise: -3.0pt; mso-font-kerning: 0pt; mso-ligatures: none; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;"> with a mean of 0.008689212 <!-- [if gte msEquation 12]><m:oMath><m:r>(</m:r><m:r>μSv</m:r><m:r>/</m:r><m:r>y</m:r><m:r>)</m:r></m:oMath><![endif]--> <span lang="EN-US" style="font-size: 11.0pt; line-height: 107%; font-family: 'Calibri',sans-serif; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: Calibri; mso-fareast-theme-font: minor-latin; mso-hansi-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-theme-font: minor-bidi; position: relative; top: 3.0pt; mso-text-raise: -3.0pt; mso-font-kerning: 0pt; mso-ligatures: none; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;"> all of which are below 0.1 <!-- [if gte msEquation 12]><m:oMath><m:r>(</m:r><m:r>μSv</m:r><m:r>/</m:r><m:r>y</m:r><m:r>)</m:r></m:oMath><![endif]--> <span lang="EN-US" style="font-size: 11.0pt; line-height: 107%; font-family: 'Calibri',sans-serif; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: Calibri; mso-fareast-theme-font: minor-latin; mso-hansi-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-theme-font: minor-bidi; position: relative; top: 3.0pt; mso-text-raise: -3.0pt; mso-font-kerning: 0pt; mso-ligatures: none; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;"> , radiogenic cancer risk (RCR) are 0.001937832, 0.000875817, 0.000610314, for adults, children and infants while for excess lifetime cancer risk (ELCR) are 3.39845×10-5, 1.53992×10-5, 1.07529×10-5 for adults, children and infants. Results reveal that there is no significant public health risk from 222Rn ingested and inhaled from sampled water within study area.
Copyright (c) 2026 Augustine Onyema Nwabuoku, Oluwadamilare Peter Olagbaju, Anita Franklin Akpolile, Omamoke O. E. Enaroseha, Ogheneovo Akpoyibo https://creativecommons.org/licenses/by-nc/4.0
Electron- phonon interaction and Electron Energy Loss Function of Spray Pyrolyzed Cu2CdSnS4 Thin Films at Different Substrate Temperatures
Cu₂CdSnS₄ (CCTS) thin films were successfully synthesized using the spray-pyrolysis method at substrate temperatures of 300 °C, 350 °C, and 400 °C. This study aimed to explore how deposition temperature impacts electron–phonon interaction, surface energy-loss function (SELF), and volume energy-loss function (VELF). X-ray diffraction (XRD) analysis showed a temperature-induced phase transition from the cernyite to the stannite structure, with crystallite size increasing from 32.5 nm to 48.3 nm. A decrease in dislocation density and microstrain, indicating improved crystallinity was noticed. Atomic Force Microscopy (AFM) analysis revealed that surface roughness increased with temperature, suggesting enhanced adatom mobility and grain coarsening. The optical absorption spectra from UV-Vis spectroscopy displayed a red-shift in the absorption edge as the temperature rose, resulting in a band gap reduction from 1.52 eV to 1.31 eV, while the refractive index slightly increased from 2.94 to 3.06. The Urbach energy also rose from 0.372 eV to 0.704 eV, indicating stronger disorder-induced tail states and enhanced electron–phonon coupling. We found that the calculated electron–phonon interaction strength increased from 5.03 eV to 8.10 eV with temperature, confirming that carrier–lattice coupling intensifies at higher growth temperatures. Both SELF and VELF increased systematically with temperature, reflecting improved crystallinity, enhanced dielectric resonance, and greater plasmonic activity. These results highlight the significant impact of substrate temperature on lattice dynamics and energy-loss mechanisms in CCTS thin films, which are crucial for optimizing absorber layers in next-generation thin-film solar cells.
Copyright (c) 2026 Michael B. Ochang, Julius N. Tsaviv, Peverga Rex Jubu, Zendesha S. Mbalaha, Bunmi J. Akeredolu, Adebayo T. Adepoju, Ngutor S. Akiiga, Augustine A. McAsule, Yushamdan Yusof, Kalu Onyekachi https://creativecommons.org/licenses/by-nc/4.0
Index Properties and Shear Strength Characteristics of Sub-Grade Soil Along Mariam-Awa Road, Southwest Nigeria
This study evaluates the index properties and shear strength characteristics of subgrade soils along the Mariam–Awa Road, Ago-Iwoye, Southwestern Nigeria. Thirty-one soil samples (18 disturbed, 13 undisturbed) were collected from 18 locations at depths between 0.4m and 1.5m. Laboratory tests conducted include grain size analysis, specific gravity, natural moisture content, Atterberg limits, compaction, California Bearing Ratio (CBR), and shear strength analysis. Grain size curves were plotted for classification and interpretation. Results showed that fines passing the No. 200 sieve ranged from 20% to 61%. Only 7 of the 18 disturbed samples met the Federal Ministry of Works and Housing (FMWH) specification of <35% fines. Specific gravity averaged 2.66, consistent with the recommended standard. Natural moisture content (6.5%–10.7%) was found to be within the permissible limits. However, Atterberg limits exceeded FMWH thresholds, with liquid limits of 41%–47%, plastic limits of 13%–16%, and plasticity indices of 28%–31%, indicating high plasticity. Maximum Dry Density (MDD) ranged from 1.808–1.898 Mg/m³, and Optimum Moisture Content (OMC) ranged from 9.8%–16%. All MDD values were satisfactory, while 14 out of the treated 18 samples had acceptable OMC (≤15%). Unsoaked and soaked CBR values ranged from 46%–86% and 22%–70%, respectively. According to approved and permissible National and International Highway and Transport Standards, only 10 samples met the unsoaked CBR requirement (≥ 80%), and 11 met the soaked requirement (≥ 30%). In conclusion, the majority of soils (68%) along the route are suitable for subgrade use, though localized weak zones require treatment.
Copyright (c) 2025 Sakirudeen Akinola Ishola, T. Oladunjoye Hamid, C. Olubunmi Ogunkoya, T. Joshua Aluko, O. Emmanuel Ogungbade, G. Muyiwa Folarin, O. Oluseyi Adeleke, H. Iyiola Kuforiji, Sunday Tanimola Olufemi, Oshinowo https://creativecommons.org/licenses/by-nc/4.0
Silane-Grafted Bamboo Fiber and SiC Dispersion-Strengthened Epoxy Composites: Mechanical Performance and Hygrothermal Durability
Recently, Biocomposites are gaining rapid industrial application due to their unlimited structural integrity and environmental sustainability. In this study, the mechanical and hygrothermal performance of epoxy matrix biocomposites reinforced with chemically modified bamboo fibers and dispersion-strengthened with silicon carbide (SiC) particulate fillers is investigated. Bamboo fibers were subjected to sequential surface treatments comprising alkaline mercerization with 0.1 N NaOH and silane coupling using the Gelest hydrolysis method, yielding four composite typologies: untreated bamboo–epoxy (UBE), NaOH-treated bamboo–epoxy (NBE), NaOH–silane-treated bamboo epoxy (NSBE), and SiC-filled NaOH–silane-treated bamboo–epoxy (NSBES). Composite laminates were fabricated by hand lay-up with compression consolidation and post-cured at 80°C. Tensile, flexural, and moisture absorption tests were conducted in accordance with ASTM D3039, ASTM D790, and ASTM D570 standards, respectively. Under dry conditions, alkali treatment (NBE) raised peak tensile strength by 23.97% over untreated composites at an optimal 15 vol% fiber loading, while combined NaOH–silane treatment (NSBE) further improved it by 39.96% to 64.8 MPa. The addition of 10 vol% SiC to the NSBE system (NSBES) yielded a peak tensile strength of 89.6 MPa, representing a 38.27% gain attributable to dispersion-strengthening mechanisms that impede matrix crack propagation. Flexural strength similarly peaked in the NSBES system, with SiC raising it by 67.32% at 10 vol% bamboo fiber loading compared to unreinforced composites. Under moisture-saturated conditions, NSBES retained the best hygrothermal stability, recording a wet tensile strength of 74.3 MPa surpassing even the dry UBE baseline of 46.3 MPa and the lowest saturation moisture content (W% = 0.92%). Moisture absorption kinetics followed a dual Fickian/non-Fickian diffusion regime, with the diffusion coefficient decreasing systematically across the treatment hierarchy. These results demonstrate that the synergistic combination of silane grafting and SiC dispersion strengthening yields high-performance, moisture-resistant natural fiber composites well-suited to structural, automotive, marine, and construction applications where both mechanical integrity and environmental durability are required.
Copyright (c) 2025 Lawretta Ogochukwu Enuenweugu, Obinichi Nnorom, Ifeanyi Uchegbulam https://creativecommons.org/licenses/by-nc/4.0
Application of Geophysical Techniques in Investigating Soil Characteristics for Oil Palm Plantation Suitability in Iyede, Delta State, Nigeria
Ten Vertical Electrical Soundings (VES) and the Schlumberger simple array technique were used to analysis the subsurface changeable conditions of the oil palm plantation at Iyede, Delta State, Nigeria. Low resistivity values (34.7–123.0 Ωm) for VES 2, 4, 6, and 7 were found using the ABEM SAS 1000 Terrameter. These results indicate a variable high moisture level, loamy soil content, fine soil texture, and soil rich in nutrients that are favorable for oil palm germination and growth in the region. The formation of coarse-medium soils were indicated by areas with sporadic greater resistivity surpassing 140 Ωm (142.6-391.6 Ωm), which may have hampered root penetration and water retention for VES 1, 3, 5, 8, 9, and 10. Analysis of the Iyede soils revealed a pH range from mildly acidic (6.8) to acidic (4.7) and consistently low nitrogen content (0.16% to 0.40%). Potassium levels varied between 0.11 to 0.61 mg/kg, while available phosphorus varied significantly from 10.81 mg/kg to 46.89 mg/kg. Overall, potassium content were low (absolutely lesser than 78 mg/kg) across all locations, below the threshold required for optimal oil palm growth. Magnesium was not a limiting factor for oil palm development at the site studied, as exchangeable magnesium levels were consistently high (36–108 mg/kg). Plant growth was positively influenced by calcium (3.45 to 8.20 mg/kg) and sodium (0.42 to 1.92 mg/kg). The use of appropriate fertilizers can further support healthy palm oil development and enhance fruit production in some oil palm farms in the study area.
Design, Fabrication, and Performance Evaluation of a Small-Scale Hybrid Solar Thermal Parabolic Trough System with Auxiliary Gas Heating for Electricity Generation in Nigeria
Energy plays a fundamental role in economic development and technological advancement. Nigeria continues to experience persistent electricity shortages due to limited generation capacity and increasing energy demand. Given the country’s high solar radiation potential, solar thermal technologies offer a promising option for decentralized electricity generation. This study presents the design, fabrication, and experimental evaluation of a small-scale hybrid solar thermal parabolic trough collector (PTC) system for electricity generation. The system consists of a 4 m long parabolic trough collector with acrylic mirror reflectors, a borosilicate glass receiver tube, water as the heat transfer fluid, a single-axis solar tracking mechanism, an auxiliary liquefied petroleum gas (LPG) heating unit, and a compact impulse steam turbine coupled to a DC generator. Experimental tests were conducted over three consecutive days between 09:00 AM and 05:00 PM. The system produced a peak electrical power output of 40.79 W. Short-duration instantaneous efficiency values approaching 26% were observed during periods of high solar irradiance; however, the average overall solar-to-electric efficiency during the experimental period was approximately 7.9%. The hybrid configuration improved operational stability during periods of low solar radiation. Performance limitations were mainly associated with low steam mass flow rate, thermal losses in the receiver and piping, and the limited efficiency of the small impulse turbine. The results demonstrate the feasibility of locally fabricated hybrid solar thermal systems for small-scale off-grid electricity generation in developing regions.
Copyright (c) 2025 Eggah Musah Yohanna; Clement Olufemi Akoshile, Emmanuel Nyam Taddy, Ezekiel Kaura Makama, Ndubuisi Emmanuel Jude Omaghali, Slyvester Banta Fierkwap
Aeromagnetic Evaluation of Structural Features and Depth to Basement at the Basement-Dahomey Basin Transition Zone, Abeokuta and Environs, Southwestern Nigeria
This study was aimed at evaluating a contact zone and structural framework between the Basement Complex and the Dahomey Basin of Southwestern Nigeria. Qualitative and quantitative analyses were used to delineate the geologic structures as well as the sedimentary thickness of <!-- [if gte msEquation 12]><m:oMath><m:r>~</m:r></m:oMath><![endif]--> <span lang="EN-US" style="font-size: 11.0pt; line-height: 107%; font-family: 'Calibri',sans-serif; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: Calibri; mso-fareast-theme-font: minor-latin; mso-hansi-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-theme-font: minor-bidi; position: relative; top: 3.0pt; mso-text-raise: -3.0pt; mso-font-kerning: 0pt; mso-ligatures: none; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;"> 55m to 575m by measurement of depth to magnetic sources. The qualitative analysis on the total magnetic intensity (TMI) data was attained by applying different filters which include reduction to the magnetic equator (RTE), tilt angle derivative (TDR), analytical signal and lineaments extraction to enhance magnetic anomalies. The quantitative analysis which includes Source Parameter Imaging (SPI) and 3D-Euler deconvolution (ED) aided the assessment of structural depth to magnetic sources. The qualitative interpretation revealed the distribution of magnetically susceptible anomalies with varying intensities across the study area. The TMI showed rightly positioned magnetic intensity range of 33,028nT to 33,087nT revealing areas of high and low magnetic intensity. The TDR ranged between -1.4nT to 1.4nT while the Analytic signal ranged between 117nT/m and 8615 nT/m with magnetic peaks in the northeast, west and southwest parts of the study area; interpreted as faulted basement blocks with delineated fault-zones trending northeast. The SPI was used in determining depth to basement and with a range of 54.1m to 599.1m. The 3D-ED ranged between -251.7m to 575.4m with observed anomaly trending in direction of NE-SW implying its conformity to Pan-African Orogeny. The Interpretation of structural features is highly significant for entrapment which can aid accumulation of valuable mineralization and localization of competent areas for proposed engineering construction.
Copyright (c) 2025 Sunday Tanimola Olufemi, Wakeel Abayomi Kareem, Sakirudeen Akinola Ishola, Joseph Olakunle Coker, Jamiu Abimbola Aladejana, Niyi Olaonipekun Adebisi, Segun Oyewole Ogunleye