Nigerian Journal of Theoretical and Environmental Physics
Nigerian Journal of Theoretical and Environmental Physics (NJTEP) is an international peer-reviewed journal that publishes articles on theoretical, experimental and environmental physics. NJTEP is a fully open access online journal published by the Nigerian Institute of Physics (NIP).
Microscopic Structural Precursors of Phase Separation in Binary Lennard–Jones Fluids
Phase separation in binary fluids is commonly identified only after concentration fluctuations develop into observable domains, leaving the earliest stages of the instability largely unexplored. Here, equilibrium molecular dynamics simulations were used to determine whether microscopic chemical ordering provides earlier evidence of phase separation in a three-dimensional binary Lennard–Jones fluid. Initially homogeneous mixtures were subjected to interaction quenches, and local coordination contrast, coordination susceptibility, radial-distribution-function contrast and concentration variance were monitored throughout the precursor regime. Persistent local chemical ordering emerged while the system remained macroscopically homogeneous, indicating that molecular neighbourhoods retain measurable signatures of the impending instability. The coordination susceptibility provided the earliest statistically significant detection at<!-- [if gte msEquation 12]><m:oMath><m:sSup><m:sSupPr><m:ctrlPr></m:ctrlPr></m:sSupPr><m:e><m:r>t</m:r></m:e><m:sup><m:r>*</m:r></m:sup></m:sSup><m:r>≈150</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;"> , followed by the mean coordination contrast<!-- [if gte msEquation 12]><m:oMath><m:r>(</m:r><m:sSup><m:sSupPr><m:ctrlPr></m:ctrlPr></m:sSupPr><m:e><m:r>t</m:r></m:e><m:sup><m:r>*</m:r></m:sup></m:sSup><m:r>≈300)</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;"> , radial-distribution-function contrast <!-- [if gte msEquation 12]><m:oMath><m:r>(</m:r><m:sSup><m:sSupPr><m:ctrlPr></m:ctrlPr></m:sSupPr><m:e><m:r>t</m:r></m:e><m:sup><m:r>*</m:r></m:sup></m:sSup><m:r>≈650)</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;"> and concentration variance<!-- [if gte msEquation 12]><m:oMath><m:r>(</m:r><m:sSup><m:sSupPr><m:ctrlPr></m:ctrlPr></m:sSupPr><m:e><m:r>t</m:r></m:e><m:sup><m:r>*</m:r></m:sup></m:sSup><m:r>≈1100)</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;"> . This sequence yielded a precursor lead time of up to <!-- [if gte msEquation 12]><m:oMath><m:r>1.1×103 </m:r><m:sSup><m:sSupPr><m:ctrlPr></m:ctrlPr></m:sSupPr><m:e><m:r>t</m:r></m:e><m:sup><m:r>*</m:r></m:sup></m:sSup></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 deep quenches, decreasing systematically as the unlike interaction approached the miscibility boundary. The detection hierarchy remained reproducible across independent simulations, with bootstrap uncertainties below 6%. These findings establish local chemical coordination as a physically interpretable and computationally efficient early indicator of phase separation, providing new insight into the microscopic onset of spinodal decomposition in binary fluids.
Copyright (c) 2024 Isaiah Eze Igwe, Zakariyya Bashir Sule https://creativecommons.org/licenses/by-nc/4.0
<span lang="EN-US" style="font-size: 10.0pt; line-height: 107%; font-family: 'Times New Roman',serif; mso-ascii-theme-font: major-bidi; mso-fareast-font-family: Calibri; mso-fareast-theme-font: minor-latin; mso-hansi-theme-font: major-bidi; mso-bidi-theme-font: major-bidi; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA; mso-bidi-font-weight: bold; mso-bidi-font-style: italic;">Noise is generally regarded as a source of disorder in active matter, yet its role in periodically driven bacterial suspensions remains poorly understood. Here, we use particle-based simulations to investigate whether stochastic tumbling can enhance the collective response of a quasi-two-dimensional suspension of run-and-tumble bacteria subjected to weak periodic motility modulation. The unforced system exhibits a transition from a homogeneous active fluid to a clustered state below a critical tumbling rate of approximately 0.42 s⁻¹, establishing the intrinsic relaxation timescale of the suspension. Under subthreshold forcing, the structural response displays a clear resonance at an intermediate tumbling rate, where the active-pressure oscillation increases by approximately 5.4-fold and the mechanical hysteresis area by 4.6-fold relative to the low-noise state. Increasing temperature shifts the optimal tumbling rate from 0.26 to 1.30 s⁻¹, reduces the maximum structural response by about 94%, and shortens the relaxation time by more than one order of magnitude. Nevertheless, both structural and mechanical responses collapse onto universal master curves when expressed as a function of <!-- [if gte msEquation 12]><m:oMath><m:r>ω</m:r><m:sSub><m:sSubPr><m:ctrlPr></m:ctrlPr></m:sSubPr><m:e><m:r>τ</m:r></m:e><m:sub><m:r>rel</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;"> <span lang="EN-US" style="font-size: 10.0pt; line-height: 107%; font-family: 'Times New Roman',serif; mso-ascii-theme-font: major-bidi; mso-fareast-font-family: Calibri; mso-fareast-theme-font: minor-latin; mso-hansi-theme-font: major-bidi; mso-bidi-theme-font: major-bidi; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA; mso-bidi-font-weight: bold; mso-bidi-font-style: italic;"> demonstrating that collective synchronization is governed by relaxation-time matching between stochastic tumbling and periodic forcing. These findings provide a simple framework for controlling organization and mechanical response in active bacterial suspensions.
Copyright (c) 2024 Isaiah Eze Igwe https://creativecommons.org/licenses/by-nc/4.0
Assessment of Indoor Radon around the Student Environment in LAUTECH Ogbomoso, Oyo State, and Its Radiological Effect on Human Organs
Indoor radon exposure constitutes a significant public health concern , being the second leading cause of Lung cancer after smoking. Upon inhalation, radon dissolve in blood and is distributed to multiply body organs.This study measured indoor radon concentration in 50 rooms around hostels in LAUTECH Ogbomoso using calibrated RAD7 active electronic detector. Measured indoor radon concentration were subsequently integrated into a validated Physiologically base Pharmacokinetics (PBPK) model to simulate radon intake and distribution. Concentrations range from 2.44 - 183.44 Bq/m3 with mean of 76.46 Bq/m3. A cluster of low concentration (1-10 Ba/m3, 32%), moderate (30 -100 Ba/m3 28%) and high (100 -180 Bq/m3, 40 %). The mean is below the 100Bq/m3 reference level recommended by WHO. Bone marrow exhibited the highest radon retention (47.4%) and highest annual effective dose 0.1776 mSv/y and the heart recorded the lowest retention (2.3 %) and effective dose of 0.0007 mSv/y. All organs effective dose were below the 1 mSv/y recommended by International commission on radiological Protection ICRP. The findings indicate that students in this environment are not at immediate radiological risk: however continuous monitoring , improved ventilation, adherence to the ALARA principle are strongly recommended
Copyright (c) 2026 Mustapha Kola LAWAL, Emmamuel Abiodun Oni, Olatunde Micheal Oni, Abraham Adewale Aremu, OLUKUNLE OLAONIPEKUN OLADAPO, Paul Sola AYANLOLA, OLUWASEUN OLOYEDE https://creativecommons.org/licenses/by-nc/4.0
Phytochemical Composition, Antioxidant Potential, and Radiological Risk of Sachet Herbal Alcoholic Drinks in Ughelli, Nigeria
Sachet herbal alcoholic drinks are widely consumed in Ughelli, Nigeria, yet their phytochemical composition and antioxidant potential remain poorly characterized. This study investigated twenty commonly consumed sachet herbal alcoholic drinks using qualitative and quantitative phytochemical screening alongside in‑vitro antioxidant assays. Results revealed that terpenes and glycosides were the most frequently detected phytochemicals, while saponins and steroids were absent. Alkaloids, tannins, and flavonoids were present in varying concentrations, with samples I, J, S, and T exhibiting higher levels of phenols (up to 0.145 mg/ml) and flavonoids (up to 0.347 mg/ml). Antioxidant assays demonstrated strong correlations between phenolic and flavonoid content and antioxidant activity, with samples I, S, and T showing the highest reducing power, and samples G and Q achieving the greatest DPPH radical scavenging activity (88.06%). Despite evidence of bioactive compounds and antioxidant potential, significant variability among brands highlights the lack of standardization and regulatory oversight. These findings provide baseline scientific data on sachet herbal alcoholic drinks in Ughelli and underscore the need for stricter quality control and toxicological evaluation to ensure consumer safety.
Copyright (c) 2026 Mudiaga Odogu, Anita Franklin Akpolile, Godwin Kparobo Agbajor, Crownbirth Ebipade Eki, Avwerusuo Amanda Ukerun-Akpesiri https://creativecommons.org/licenses/by-nc/4.0
Quantum Simulation of Strongly Correlated Electron Systems for Next-Generation Superconducting Technology
We report a systematic quantum simulation study of strongly correlated electron systems described by the 2D Fermi-Hubbard model, executed across superconducting quantum processors ranging from 16 to 127 qubits. Employing variational quantum eigensolver protocols combined with probabilistic error cancellation and zero-noise extrapolation mitigation techniques, we characterized ground-state energies, spin-spin correlation functions, and d-wave superconducting pairing correlations over the parameter regime, U/t ∈ [2, 12] and doping levels δ ∈ [0.05, 0.25]. Errors in the ground-state energy for simulations were found to be within 3.2 mHa per site relative to the density matrix renormalization group (DMRG) benchmark for circuit depths up to 400 two-qubit gate layers and a 127-qubit scale. The extracted d-wave pairing susceptibility had a distinct peak at U/t ≈ 8.0 and δ ≈ 0.15, which is comparable to the theoretically predicted values of cuprate-class high-temperature superconductors. Quantum advantage onset is identified at system sizes beyond 48 qubits under realistic noise conditions when tensor network classical simulation costs become prohibitive. The findings provide a clear-cut computational roadmap from the ability of quantum hardware to predictive modelling of superconducting pairing mechanisms, directly informing materials design for next-generation superconducting technologies.
Copyright (c) 2026 Doris Ngozi Nwachuku, Ethel Osiegbu https://creativecommons.org/licenses/by-nc/4.0
Evaluation of Radioactivity and Potential Radiological Health Risks of Mined Soils Used as Building Materials in Ijero-Ekiti, Nigeria
The utilization of mined soils in building construction has raised serious concerns about radiological hazards to the public due to elevated concentrations of naturally occurring radioactive materials (NORMs). This study assesses the natural radioactivity levels and potential radiological health risks associated with mined soils commonly used as building materials in Ijero-Ekiti, a major mining community in Southwestern Nigeria. Gamma spectrometry analysis was performed on thirty (30) randomly sampled mined soil samples using a high-purity Germanium (HPGe) detector to determine activity concentrations of the radium-226 (226Ra), uranium-238 (238U), thorium-232 (232Th), and potassium-40 (40K). Radiological models based on these measured activity concentrations were used to evaluate potential health risk indicators, including hazard indices (Hex and Hin), Annual Gonadal Dose Equivalent (AGDE), annual effective dose (AEDout and AEDin), radium equivalent activity (Raeq), and excess lifetime cancer risk (ELCR). The average activity concentrations of 226Ra, 238U, 232Th, and 40K in the samples were 512.28 ± 26.76, 241.26 ± 12.55, 31.07 ± 3.56, and 2808.01 ± 148.52 Bq/kg, respectively. Radionuclide concentrations and calculated health risk indicators exceeded global average values reported by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) and recommended safe limits set by the International Atomic Energy Agency (IAEA). These findings indicate elevated ionizing radiation levels in the samples, posing potential radiological health risks to exposed residents. To address these concerns, stringent policies, public awareness, further research, and safer building materials are recommended.
Copyright (c) 2026 Oluseye Sunday Olayemi, Shamsideen Kunle Alausa, Joseph Olakunle Coker, Yinka Ajiboye, Adetoro Temitope Talabi, Aliu Olayinka Olabamiji https://creativecommons.org/licenses/by-nc/4.0
Smart Physics Approaches for Climate Change Impact Assessment on Sweetcorn Evapotranspiration and Yield across Nigeria’s Agro-Ecological Zones under Different Climate Scenarios
Climate change has emerged as one of the most critical environmental challenges affecting agricultural sustainability, hydrological systems and food security globally. In Nigeria, increasing temperature, rainfall variability and hydro-climatic extremes pose severe threats to rain-fed agricultural systems, particularly cereals production across diverse agro-ecological zones. This study applies smart physics-based approaches involving climate modelling, agro-hydrological simulations, data analysis and advanced environmental modelling tools to evaluate the impacts of climate change on maize evapotranspiration (ET) and yield under Representative Concentration Pathways (RCP2.6 and RCP8.5). Climate projections derived from HadGEM2-ES, NorESM1-M and MPI-ESM-MR models were integrated with the DSSAT CERESmaize model to assess future crop responses across rainforest, savannah and Sahel ecological zones in Nigeria. Results indicate substantial warming under future scenarios, with temperature increases exceeding 7°C under RCP8.5 in the Sahel. Evapotranspiration demand increased significantly across all regions due to intensified atmospheric evaporative demand, while maize yield declined sharply under high emission scenarios. Yield-to-Evapotranspiration efficiency (YPEM) deteriorated substantially, particularly in savannah and Sahel regions, indicating increasing hydro-agricultural stress and declining water-use efficiency. The findings provide scientific evidence for climate adaptation, technological innovation and sustainable agricultural management in Nigeria.
Copyright (c) 2026 Otori Muhammed Yahaya, Emmanuel Ogolo, Mathew Olaniran, Agele Samuel, Vincent Olanrewaju Ajayi https://creativecommons.org/licenses/by-nc/4.0
Exploring the Role of Binary Mass Ratio (q = 0.1, 1.0) in Shaping Gravitational Wave Amplitude, Frequency Evolution, and Waveform Morphology
Compact binary mass ratio (<!-- [if gte msEquation 12]><m:oMath><m:r>q</m:r><m:r>=</m:r><m:f><m:fPr><m:ctrlPr></m:ctrlPr></m:fPr><m:num><m:sSub><m:sSubPr><m:ctrlPr></m:ctrlPr></m:sSubPr><m:e><m:r>m</m:r></m:e><m:sub><m:r>2</m:r></m:sub></m:sSub></m:num><m:den><m:sSub><m:sSubPr><m:ctrlPr></m:ctrlPr></m:sSubPr><m:e><m:r>m</m:r></m:e><m:sub><m:r>1</m:r></m:sub></m:sSub></m:den></m:f><m:r>=0.1, 1.0=) </m:r></m:oMath><![endif]--> <span lang="EN-GB" 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: 'Times New Roman'; mso-bidi-theme-font: minor-bidi; position: relative; top: 7.5pt; mso-text-raise: -7.5pt; mso-font-kerning: 0pt; mso-ligatures: none; mso-ansi-language: EN-GB; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;"> lays a critical role in shaping the characteristics of gravitational waves (GWs) emitted during the inspiral, merger, and ringdown phases. This study employs numerical relativity (NR) simulations using the Einstein Toolkit to model binary black hole systems and examine the dependence of waveform amplitude, frequency evolution, and morphology on mass ratio. Equal-mass binaries <!-- [if gte msEquation 12]><m:oMath><m:r>(</m:r><m:r>q</m:r><m:r>≈1)</m:r></m:oMath><![endif]--> <span lang="EN-GB" 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: 'Times New Roman'; 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-GB; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;"> produce symmetric, high-amplitude signals with smooth chirp behaviour, whereas increasingly asymmetric systems (<!-- [if gte msEquation 12]><m:oMath><m:r>q</m:r><m:r>=0.1</m:r></m:oMath><![endif]--> <span lang="EN-GB" 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: 'Times New Roman'; 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-GB; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;"> ) exhibit reduced amplitudes, precession-induced modulations, and enhanced excitation of higher-order modes. The results indicate amplitude reductions of up to 40% for <!-- [if gte msEquation 12]><m:oMath><m:r>q</m:r><m:r>=0.1</m:r></m:oMath><![endif]--> <span lang="EN-GB" 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: 'Times New Roman'; 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-GB; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;"> relative to <!-- [if gte msEquation 12]><m:oMath><m:r>q</m:r><m:r>=1.0</m:r></m:oMath><![endif]--> <span lang="EN-GB" 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: 'Times New Roman'; 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-GB; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;"> , slower chirp rates, and waveform mismatches exceeding 1% in post-Newtonian models for strongly asymmetric configurations. These findings highlight the importance of accurately accounting for mass-ratio effects in gravitational-wave template banks, with direct implications for improved parameter estimation in LIGO–Virgo–KAGRA observations and future detectors such as LISA.
Copyright (c) 2026 David Girma, Bakwa Dirting, Yerima Jabil, Davou Lawrence, Bukar Bringen https://creativecommons.org/licenses/by-nc/4.0
Assessment of Leakage and Scattered Radiation in Selected Computed Tomography Facilities over Jos, Plateau State, Nigeria
This study assessed leakage and scattered radiation levels in three computed tomography (CT) facilities in Jos, Plateau State, Nigeria, as part of routine quality assurance and radiation safety evaluation. A calibrated GMC-600 digital Geiger Muller counter was employed to measure radiation levels, ensuring traceability to national calibration standards. The detector was positioned at 1 m from the gantry in four different directions (front, back, left, right) to determine leakage radiation, and at the console area to quantify scattered radiation during phantom exposures. The mean leakage radiation values recorded were 6.94, 5.93, and 8.97 mR/hr for facilities X1, X2, and X3, respectively. Mean scattered radiation levels at the console areas were 3.62, 2.14, and 2.94 mR/week. All results were well below the American Association of Physicists in Medicine (AAPM) recommended limits of 100 mR/hr for leakage and 10 mR/week for scatter, indicating full compliance with international safety standards. Statistical analysis revealed significant variation in leakage radiation between facilities (p < 0.05), with older equipment demonstrating higher leakage values. These findings suggest that equipment age and shielding design may influence radiation safety performance. Although compliance was achieved across all facilities, the study emphasizes the importance of periodic monitoring, preferably on an annual basis, to ensure sustained adherence to safety standards. Furthermore, integrating occupational dose monitoring and image quality assessments into routine quality control programs will strengthen radiation protection practices, optimize patient safety, and safeguard radiology personnel in resource-limited settings.
Copyright (c) 2026 Stephen D. Pam, Anita Franklin Akpolile, Franklin D. Akpolile, Crownbirth Ebipade Eki, Habila Ishaya https://creativecommons.org/licenses/by-nc/4.0
Theoretical Modelling of InPBi/InGaAs Quantum Dot Superlattices for Intermediate Band-Based Solar Cell Applications
Dilute bismide alloys such as InPBi exhibit strong bandgap reduction and enhanced spin-orbit splitting, making them promising candidates for intermediate band (IB) optoelectronic devices, including intermediate band solar cells (IBSCs). This report presents comprehensive Kronig-Penney model simulations of InPBi/AlGaAs quantum dot superlattices (QDSLs) for Intermediate band solar cell (IBSC) applications. The intermediate band (IB) characteristics including IB width, valence band to IB gaps and IB to conduction band gaps are systematically investigated as functions of well width and barrier thickness. Results are compared with existing theoretical models and experimental studies on similar material systems, including InAs/GaAs quantum dots and dilute bismide alloys. The simulations reveal optimal structural parameters achieving nearly balanced gaps within an IB width of 0.154 eV. These findings agree well with experimental report on InAs/GaAs quantum dot IBSCs and theoretical predictions for dilute nitride and bismide systems validating the applicability of the Kronig-Penney model for QDSL design.
Copyright (c) 2026 IKEDICHUKWU ONYEKWERE, Oriaku Chijioke, Nnanna Lebe, Elizabeth Chinyereb Nwaokorongwu, Joseph Ugochukwu https://creativecommons.org/licenses/by-nc/4.0
Measurement of Ambient Dose Rates in the Near and Far Field of Selected Cement Stores in Ogun State, South-West, Nigeria
The current economic hardship in the nation has resulted in many citizens looking for more jobs that can be done to make ends meet. Sales of cement in small and large scales can be seen everywhere. The young and elderly are involved in the business, which predisposes the workers and the public in the vicinity of the stores to ionizing radiation in cements stockpiled. The dose rates in the near and far fields of the selected cement store for the study have been investigated. Eight cement stores were selected across the study areas, and the dose rates in the near and far fields of the stores were measured using an FNIRSI GC-01 dosimeter. The radiological parameters associated with the exposure of workers and the general public were estimated for 10 years using a software called the URANIUM WISE project. The mean of the measured dose rates for the near and far fields of the cement stores ranged from (0.07 ̶ 0.27) µSv/h. The estimated radio-logical parameters for the study are above the recommended values by different regulatory bodies. This may have negative health implications for the workers and the public.
Copyright (c) 2026 ABAYOMI AJETUNMOBI, Janet Odogboro, Dare Adeniji, Ebibuloami Biere, Abdulganiu Adeniji, Rufus Trufus Akinnubi, Adetoro Temitope Talabi, Shamsideen Kunle Alausa, Timothy Wemimo David, Patrick Adeleye https://creativecommons.org/licenses/by-nc/4.0
Comparative Analysis of ITU-R P.618-14 and Ajayi-Olsen Models for Rain-Induced Signal Attenuation on Aviation Satellite Communication Links in Some Northern Nigeria
Rain-induced signal attenuation remains one of the most critical impairments affecting satellite communication links operating above 10 GHz in tropical environments. This study presents a comparative analysis of the ITU-R P.618-14 standard model and the Ajayi-Olsen tropical propagation model for predicting rain attenuation on aviation satellite communication links across four selected states in Northern Nigeria; Abuja/FCT, Kaduna, Jos/Plateau, and Sokoto. Five years of daily rainfall data (2021–2025) obtained from the Nigerian Meteorological Agency (NiMET) were fitted to a Gamma distribution to derive the 0.01% exceedance rain rate (R0.01) for each station. Both models were applied at Ku-band (12 GHz) and Ka-band (30 GHz). Results reveal that R0.01 values range from 1.827 mm/hr at Abuja to 4.415 mm/hr at Sokoto. The Ajayi-Olsen model consistently predicts 8–10% higher Ku-band attenuation than ITU-R P.618-14, confirming that the global model underestimates rain attenuation in Northern Nigeria. Ka-band attenuation A0.01 ranges from 1.911 dB at Abuja to 4.330 dB at Sokoto under ITU-R predictions. A Ku-band correction factor of +10% to ITU-R predictions is recommended for aviation satellite link budget design across Northern Nigeria.
Copyright (c) 2026 Aishat Altine Modibbo, Philip Musa Gyuk, Shuaibu Alhassan, Nicholas Kure, Abubakar Muhammad Tyabo, Bashir Wali Mustapha https://creativecommons.org/licenses/by-nc/4.0
A Unified Model for Size-, Shape-, and Composition-Dependent Bandgap in Semiconductor Nanocrystals: Beyond the Effective Mass Approximation
Quantum confinement in semiconductor nanocrystals enables precise bandgap engineering for optoelectronic applications. The Brus equation provides a foundational description for spherical particles but cannot account for shape anisotropy, surface states, or compositional inhomogeneity in alloyed systems. This work presents a unified analytical model that extends the Brus equation by incorporating three physically motivated elements: a shape-dependent confinement energy derived from an infinite-barrier box model and expressed through an anisotropy factor α_conf; a negative surface-state correction proportional to the surface-to-volume ratio that defines a critical radius for surface-dominated behaviour; and three mixing rules for binary semiconductor nanoalloys. The most advanced mixing rule, Rule S, couples a modified Butler isotherm to the confinement model to capture surface segregation. Validation against 28 experimental data points encompassing CdSe spheres, cubes, and rods, PbS quantum dots, and alloyed Cd1-xZnxS nanocrystals yields an overall root-mean-square error of 0.07 eV, representing up to a factor-of-five improvement over the original Brus equation for anisotropic particles (3.2× for CdSe rods, 4.7× for PbS spheres). The fully analytical model evaluates a single composition–size–shape configuration in 2 - 5 ms, enabling the screening of thousands of candidates per minute on standard hardware. This framework provides a computationally efficient and physically transparent tool for predictive bandgap engineering in semiconductor nanocrystals.
Copyright (c) 2026 Abdulrahaman Babajide Ogunji, Abayomi Stephen, Hanaa Almaghamsi, Adesanya Oluwafemi Atilade https://creativecommons.org/licenses/by-nc/4.0
Growth Dynamics and Characterization of FeCuS Thin Films: A Computational Framework Using a hybrid kMC–DFT Approach
Iron copper sulphide (FeCuS) thin films have recently attracted increasing attention in materials science and renewable energy research because of their favourable semiconducting, optical, and electronic properties. Their suitability for photovoltaic devices, photodetectors, and other optoelectronic systems has been linked to their narrow band gap, high absorption coefficient, and abundant constituent elements. Despite these promising properties, limited understanding has been achieved regarding the growth mechanisms and microscopic structural evolution controlling film performance. Consequently, computational techniques have been recognised as essential tools for predicting and optimising atomic-scale thin-film behaviour and establishing relationships between deposition processes and functional properties. This study employs a hybrid computational framework combining kinetic Monte Carlo and Density Functional Theory (kMC–DFT) to investigate growth dynamics, structural evolution, and optoelectronic characteristics of iron copper sulphide (FeCuS) thin films. This approach addresses the current limitation in correlating growth mechanisms with material functionality, thereby providing a deeper theoretical understanding of FeCuS thin film formation. The FeCuS thin film simulated exhibits excellent deposition characteristics, with complete lattice occupation, smooth morphology, and balanced composition. The estimated band gap of 0.83 eV confirms semiconducting behaviour, making the film a promising candidate for solar cell absorbers, photodetectors, and energy conversion devices.
Copyright (c) 2026 Ayobamidele Dele Adelaja, Temitope Olasile Fowodu, Qasim Abolanle Adeniji, Kayode Johnson Bamidele, Musa Adekunle Fagbohun https://creativecommons.org/licenses/by-nc/4.0
AI-Enabled Optimization of Radioactive Waste Management at the Nigeria Research Reactor-1
Efficient management of radioactive waste generated in research reactors remains an important operational and regulatory challenge, particularly in facilities with limited storage capacity and heterogeneous waste streams. This study presents an AI-enabled decision-support framework for optimizing radioactive waste management at the Nigeria Research Reactor-1 (NIRR-1), a 30 kW miniature neutron source reactor. The framework integrates deterministic radioactive decay modeling, machine learning–based waste classification, activity forecasting, and constrained multi-objective optimization. Waste inventory data were analyzed using a Random Forest classifier and regression-based activity prediction models, followed by Pareto-based optimization of storage scheduling under regulatory clearance constraints. The classification model achieved an accuracy of 93.7%, while activity forecasting produced a coefficient of determination R2 = 0.993 with normalized prediction errors below 5%. Optimization results indicate that systematic decay-informed scheduling can reduce projected storage congestion from 82% to 61%, while the integrated AI–optimization framework further reduces storage utilization to approximately 50.8%. The results demonstrate that combining decay physics with data-driven optimization can significantly enhance operational efficiency without compromising regulatory compliance. The proposed framework provides a practical computational tool for improving radioactive waste management at research reactor facilities.
Copyright (c) 2026 Joseph Toba Afolayan, Emmanuel Joseph, Isaiah Eze Igwe https://creativecommons.org/licenses/by-nc/4.0
Impact of Interfacial Layer Composition and Thickness on Schottky Diode Barrier Height and Ideality Factor
This work studies the effect of an interfacial layer on the electrical properties of Schottky diodes contacts formed with three metals - Chromium (Cr), Tungsten (W), and Molybdenum (Mo) - in contact with n-type Germanium (Ge). The electrical parameters studied include the saturation current (Iₛ), barrier height (<!-- [if gte msEquation 12]><m:oMath><m:sSub><m:sSubPr><m:ctrlPr></m:ctrlPr></m:sSubPr><m:e><m:r>Φ</m:r></m:e><m:sub><m:r>B</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;"> ), ideality factor (n), and series resistance (Rₛ) at 300 K. Using Cheung’s model and the modified Cheung’s model, voltage values ranging from 0.09 V to 0.15 V were simulated, consistent with the operational conditions of the models. Results indicate that Cr/n-type Ge and Cr/interfacial-layer/n-type Ge provide the most efficient rectifying contacts, exhibiting optimal barrier heights and low series resistances. These findings highlight the significant role of interfacial layer composition and thickness in tuning Schottky diode performance.
Copyright (c) 2026 Dlama Yabwa, Akpevwe Ejiro Ohworho https://creativecommons.org/licenses/by-nc/4.0
Assessing the Feasibility of Nuclear Techniques for the Analysis and Conservation of Cultural Heritage in Katsina State, Nigeria
Nuclear techniques provide non-destructive, highly precise methods for the analysis, restoration, and preservation of irreplaceable cultural heritage objects and sites. This review assesses the feasibility of applying techniques such as neutron activation analysis (NAA), X-ray fluorescence (XRF), particle-induced X-ray emission (PIXE), and gamma irradiation for cultural heritage in Katsina State, Nigeria. Katsina hosts significant tangible heritage, including the Gobarau Minaret, Durbi Takusheyi tumuli, ancient city walls, Emir’s Palaces, and collections at the National Museum Katsina, which face threats from erosion, biological degradation, climate variability, and urbanization. Nigeria’s nuclear infrastructure, coordinated by the Nigerian Atomic Energy Commission (NAEC), includes the Miniature Neutron Source Reactor (NIRR-1) at the Centre for Energy Research and Training (CERT) in Zaria and the Gamma Irradiation Facility (GIF) at Sheda, Abuja, offering a viable foundation for peaceful applications. Drawing on IAEA-supported global projects, this paper evaluates technical, economic, regulatory, institutional, and socio-cultural dimensions of feasibility. Opportunities through IAEA technical cooperation outweigh challenges such as expertise gaps and equipment access, making implementation promising. Recommendations focus on pilot projects, capacity building, and stakeholder collaboration to enhance heritage preservation and socioeconomic benefits.
Copyright (c) 2026 Emmanuel Joseph, Uma Helen Emmanuel, Abubakar Abdullahi https://creativecommons.org/licenses/by-nc/4.0
Measurements of Background Ionizing Radiation Levels in Selected Farms in Agbor, Delta State, Nigeria
Measurements of Background Ionizing radiation (BIR) levels were carried out in six farms with a calibrated Digilert-200 radiation meter positioned 1.0 m above the ground level. Geographical positioning system (GPS) was also used to find the coordinates of each studied farm. The measured overall average BIR exposure rate across the selected farms was 3.78 µR/h. Using radiological relations, the health risks parameters and the radiation effective doses to different organs/ tissues were determined as follow: Mean equivalent dose rate 0.03 µSv/h), Mean absorbed dose rate (33.09 nGy/h), mean annual effective dose equivalent (0.05 mSv/y), mean excess life cancer risk (0.14 × 10-3. These values were lower than the recommended permissible limits of 13 µR/h, 0.1µSv/h, 84.0 nGy/h, 1.0 mSv/y and 0.29 × 10-3 respectively as recommended by (International Commission on Radiological Protection (ICRP) and United Nations Scientiﬁc Committee on the effects of Atomic Radiation (UNSCAER). Similarly, the effective dose delivered to different organs of the body within the recommended limits of 1.0 mSv/y. The results showed that the study area is safe from radiation exposure contamination.
Copyright (c) 2026 Nigerian Journal of Theoretical and Environmental Physics
Assessment of Entrance Surface Air Kerma and Effective Dose for Adult Patients Undergoing Conventional Diagnostic X-Ray Examinations in Selected Hospitals in Ogbomoso, Oyo State, Nigeria
Diagnostic x-ray examinations are key part of modern medical imaging, helping doctors to diagnose a range of health conditions. However, these procedures expose patients to ionising radiation, which carries certain risks that need careful management. This study therefore assessed the entrance surface air kerma (ESAK) and effective dose (ED) for 1583 adult patients undergoing seven common diagnostic examinations at three different hospitals in Ogbomoso, Oyo State, Nigeria using CalDose software. The results of the study ranged from 0.67 – 6.78 mGy for ESAK and 0.02 – 0.48 mSv for ED. Among the examinations considered, the lumbar spine produced the highest ESAK values across the three hospitals, for both male and female patients, with an effective dose of 0.44 mSv at X, 0.29 mSv at Y, and 0.48 mSv at Z, while the chest had the lowest dose (X= 0.06, Y = 0.02, Z = 0.02 mSv). The estimated effective doses were within the safe limits set by the International Commission on Radiological Protection. These findings emphasise the need for regular dose audits, careful optimisation of exposure settings, and ongoing staff training to reduce patient radiation exposure while maintaining good diagnostic quality.
Fundamental Physical Principles and Clinical Applications of Proton Therapy: A Comprehensive Review
Proton therapy is an advanced modality in external beam radiotherapy that exploits the unique depth-dose distribution of accelerated protons to achieve improved tumor targeting compared with conventional photon-based techniques in selected anatomical geometries. This review synthesizes the fundamental physical principles underlying proton therapy, including proton-matter interactions, stopping power, linear energy transfer (LET), the Bragg peak, and the generation of the spread-out Bragg peak (SOBP). Accelerator technologies such as cyclotrons and synchrotrons, beam delivery methods including passive scattering and pencil beam scanning, and treatment planning approaches incorporating proton computed tomography and range verification are examined. The radiobiological effectiveness of protons is discussed alongside emerging evidence for FLASH proton therapy, which delivers ultra-high dose rates (>40 Gy/s) currently under early-stage clinical investigation. Clinical applications are supported by Level I evidence from randomized controlled trials (e.g., the 2025 Lancet trial demonstrating 90.9% versus 81.0% five-year overall survival for oropharyngeal cancer), Level II evidence from prospective cohort studies, and Level III evidence from meta-analyses showing reduced toxicity and secondary malignancy risks in pediatric cancers and central nervous system tumors. Despite challenges such as range uncertainty and high facility costs, proton therapy continues to evolve as a component of precision oncology in appropriately selected patients. This review underscores how fundamental physics principles translate into measurable clinical benefits when applied to specific tumor sites and patient populations.
Evaluating the Accuracy of MERRA-2 Reanalysis Data Against In-Situ Observations Under Varying Weather Conditions
Accurate estimation of surface atmospheric parameters is essential for climate and environmental studies, especially in regions with limited ground-based observations. This study addressed a key gap by evaluating Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) reanalysis data against in-situ measurements of solar radiation, temperature, and wind speed under varying weather conditions. In-situ data were collected in Osogbo, Osun State, Nigeria, using a Professional Weather Station and a Solar Meter (SM205), while MERRA-2 data were obtained from the NASA GIOVANNI platform, covering January 1 to March 31, 2025. Data were synchronized to hourly resolution and categorized by weather type. Statistical analysis applied linear, quadratic, and logarithmic regression models, with performance evaluated using Root Mean Square Error (RMSE) and Coefficient of Determination (R²). Results showed strong agreement between MERRA-2 and in-situ temperature across most conditions, with the quadratic model performing best. Under sunny conditions, R² reached 0.994 and 0.948, with RMSEs of 0.27 °C and 0.62 °C. Overcast days also showed good reliability (R² = 0.860 and 0.767), though accuracy declined during rainfall (R² = 0.377; RMSE = 2.61 °C). For solar irradiance, performance varied by condition: the quadratic model performed best on sunny Day 1 (R² = 0.759), while the logarithmic model gave the lowest RMSE on Day 2 (114.78 W/m²). Overcast and rainy Day 2 favored the quadratic model (R² = 0.925 and 0.881). Wind speed showed poor agreement across all conditions, with best R² = 0.289 and RMSE up to 8.97 m/s.
Evaluation of Radiofrequency Power Flux Density from Mobile Base Transceiver Stations in Gidan-Mangoro, Bosso Local Government Area, Niger State, Nigeria
Radiofrequency (RF) radiation emitted from Global System for Mobile Communication (GSM) Base Transceiver Stations (BTS) is classified as non-ionizing radiation. Nevertheless, concerns have been expressed worldwide regarding the possible health effects associated with prolonged exposure, particularly for individuals residing close to BTS installations. The International Agency for Research on Cancer has categorized RF electromagnetic fields as possibly carcinogenic to humans (Group 2B), highlighting the need for continued scientific investigation. This study evaluated the power flux density of RF radiation emitted from mobile transceiver stations located near residential areas of Gidan-Mangoro in Bosso Local Government Area of Niger State in order to determine compliance with safety standards recommended by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). Measurements of signal levels from three mobile network operators (MTN, GLO and Airtel) available within the study area were carried out using an RF Strength Meter (Model 480836). Several measurements were taken along all the accessible routes to cover the study area, while the corresponding distances and geographic coordinates were recorded using a Global Positioning System (GPS) device. The results indicated that power flux density varied across different locations, largely influenced by environmental conditions such as terrain, buildings, and vegetation. Despite these variations, the highest recorded value was 109.4 mW/m², which is below the ICNIRP recommended public exposure limits of 4,500 mW/m² (900 MHz), 9,000 mW/m² (1,800 MHz) and 10,000 mW/m² (2,700 MHz). These findings suggest that RF exposure levels within the study area remain within internationally accepted safety limits.
Assessment of Natural Radioactivity Levels and Radiological Health Risks in Coastal Sediments of the Niger Delta, Nigeria: Environmental and Human Health Implications
Unregulated discharge of hydrocarbon-related wastes into Niger Delta coastal waters raises concerns over radionuclide contamination of sediments used in construction within the coastal region. Hence sediment samples were analyzed radiologically by means of Sodium iodide detector NaI (Tl). The mean concentration of 40K, 238U and 232Th that were analyzed are 1586.80, 27.25 and 46.90 Bq/kg respectively. The obtained values exceeded the world standard values of 400 and 30 Bq/kg for 40K and 232Th respectively while 238U is below standard value of 35 Bq/kg. The computed radiological indices with the view of ascertaining the sediment contamination level are radium equivalent activity, representative gamma index, the internal and external hazard index, absorbed gamma dose rate, annual effective dose equivalent and excess lifetime cancer risk with overall mean values of 216.50 Bqkg− 1, 1.70, 0.60, 0.65, 107.80 nGyh− 1, 0.13 mSvyr− 1 and ~4.6 × 10-3 respectively. These radiological indices exceeded respective recommended permissible limits. The research work concludes that unprofessional discharge of radiological contamination waste can lead to contamination of the coastal sediment being use for construction, and can further affect health of the residents in the region. However, these results can be use in the future as baseline for further radiological research.
Assessment of Natural Radionuclides Concentrations and Radiological Hazards from Soil Samples in Alabata and Its Environs, Ogun State, Southwestern Nigeria
The natural occurring level of radioactivity in any soil is one of the main causes of external gamma exposure. The activity concentrations of natural radionuclides from soils in granitic area of Alabata, southwest Nigeria were determined with the aim of knowing the levels and evaluating the radiological hazards. Soil samples were collected and analysed by gamma-ray spectrometry method utilizing NaI scintillation detector. Results show that the ranges (and the conforming average values) of the estimated activity concentrations for 238 U, 232Th and 40K are 6.46 <!-- [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;"> 0.00 to 66.57 <!-- [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;"> 15.05; 211.56 <!-- [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;"> 96.10 to 6.46 <!-- [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;"> 0.00, and 211.56 ± 96.10 to 470.02 <!-- [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;"> 91.28 Bq/Kg, respectively. 238U was mostly below detection limits (BDL) All the estimated radiological hazards were observed to be within the threshold limit of 370 Bq/kg, 60 nGy/h per UNSCEAR standards, 1 mSv/yr, 1.45 × 10⁻³, and 1 for radium equivalent activity, absorbed dose rate, effective dose, excess life cancer risk, and external and internal hazard index respectively as recommended by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), Specifying that 238U was mostly below detection limits (BDL). Further investigation into the levels and radiation exposures of quarry soils within the vicinity of the study area is highly suggested.
Three-state Hidden Markov Model of Air Temperature Regimes over the Middle Belt States of Nigeria
This research applies a three-state Hidden Markov Model (HMM) to thirty (30) years (1991-2020) daily air temperature data over the Middle Belt states (Abuja, Benue, Kogi, Kwara, Nasarawa, Niger and Plateau) of Nigeria to identify the unique temperature regimes, characterize their distributional properties, and examine their temporal dynamics. Based on the state-dependent mean temperatures and standard deviation, the model divided the daily air temperature data series into three statistically different temperature regimes: regime 1 (Cool), regime 2 (Moderate), and regime 3 (Warm). Results show that the Warm (above average) regime dominates the majority of the time period, while the moderate (in-between) regime typically represents changes between transitional periods and the cool (below average) regime is associated primarily with the Harmattan (Northeast Trade Wind) Season. Transitions from Regime 1 (Cool) to Regime 2 (Moderate) and from Regime 2 to Regime 3 (Warm) happen more often than direct transitions from Regime 1 to Regime 3 as revealed by the Transition Probability Matrix. Warm regime occupancy reaches 54.4% in Benue and 45.7% in Kogi, indicating that high air temperature conditions dominate mainly in such area. The overall structure of the HMM used in this work provides a physical description of the temperature variability experienced by the Middle Belt States, Nigeria. Hence, creating a useful opportunities for assessments of climate variability, supporting heat-risk mapping and adaptation planning.
Using Machine Learning To Predict Rainfall in Abeokuta Nigeria
Rainfall is extremely important in Abeokuta as it supports agriculture, influences daily life, and the local economy. Abeokuta receives substantial seasonal precipitation; however, variability poses significant risks. This work focuses on Abeokuta and examines rainfall variability from 2001 to 2010. Using machine learning models is one way to extract information, patterns, and trends from historical data, enabling stakeholders to make informed decisions. It is essential to measure the climatic variables that correlate with rainfall, as this will help identify ways to mitigate their effects in pursuit of a balanced nature. In this study, the Seasonal Autoregressive Integrated Moving Average (SARIMA), Random Forest (RF), and Artificial Neural Network (ANN) were used to examine seasonality and patterns in our dataset for predictive purposes. The results show that the ANN model's MSE (7767.4691) and MAE (64.7500) are the lowest among the models used in this work. This suggests that the ANN model's predictions are closer to the actual rainfall values than those of other models. Furthermore, a correlation analysis revealed that the ANN correlated with evaporation and relative humidity. This suggests that during wet seasons or prolonged rainy periods, when rainfall is high, evaporation is low, and less irrigation may be needed, but soils stay wet longer. This might result in flooding. In contrast, in dry seasons with little rain, evaporation is high, and soils dry out quickly, increasing irrigation demand.
Hydrogeophysical Investigation of Groundwater Potential in Ugbowo Area of Edo State Using Electrical Resistivity Method
A hydrogeophysical investigation of groundwater potential was conducted in the Ugbowo area of Edo State, Nigeria, using Electrical Resistivity Method to characterize the subsurface lithology and evaluate groundwater potential. A Global Positioning System (GPS) receiver was used to obtain the geodetic coordinates of the VES station, which is located at latitude 6° 28′ 48.36″ N and longitude 5° 35′ 17.16″ E. The geology of the study area is predominantly composed of the Benin Formation, which underlies approximately 95% of the region. Vertical Electrical Sounding (VES) was performed at one station using the SAS 300C ABEM Terrameter with the Schlumberger array configuration and a maximum electrode spacing of 147 m. The acquired data were processed and interpreted using the IPI2WIN software. The resulting geoelectric model revealed six subsurface layers with apparent resistivity values ranging from 391.51 Ωm to 5836.9 Ωm and depths extending from 1.41 m to 85.23 m. The lithologic units identified include lateritic topsoil, clay, gravel, cemented sandstones, and fine- to coarse-grained sands of varying thicknesses. The aquifer units were predominantly confined and showed good correspondence with lithologic logs from existing boreholes within the study area. A high resistivity lateritic layer was found to dominate the upper subsurface. The Vertical Electrical Sounding (VES) results indicate the presence of an aquifer with a resistivity of 783.37 Ωm, located directly below the fifth layer in the study area. This potential aquifer suggests that the area may be suitable for groundwater development. Based on these findings, it is recommended that drilling contractors consider this information before borehole construction to enhance the efficiency and success of groundwater exploration.
Thermo-Magnetic properties of Two-Dimensional Non-Relativistic Schrödinger Equation for the Attractive Radial Potential under External Magnetic and Aharonov-Bohm Flux Fields
We investigate the thermo-magnetic properties of the Attractive Radial Potential (ARP) for a particle moving in two-dimensional non-relativistic Schrödinger equation subjected to an external magnetic field and Aharonov-Bohm (AB) flux. Analytical solution for the energy eigenvalues and wavefunctions were obtained in a closed form via the Nikiforov-Uvarov Functional Analysis (NUFA) method. We derived the partition function by analyzing the system as a canonical ensemble to obtain the expressions for the thermodynamic quantities which include the free energy, entropy, specific heat capacity and internal energy. Our results show a decrease in the energy spectrum when the AB flux and magnetic fields are increased. At low temperatures, specific heat capacity shows a peak anomaly, while Helmholtz free energy and entropy exhibit temperature dependence. We also observed that AB flux and magnetic field influence both magnetization and magnetic susceptibility and exhibit both paramagnetic and diamagnetic behavior. The findings provide valuable insights into in molecular physics applications.
Embedded System Application for Establishing Variability and the Relationship Between Meteorological Parameters and Particulate Matter Pollution in a Lagos Site
Air pollution from particulate matter (PM) remains a major environmental and public health concern, particularly in rapidly urbanizing cities. This study investigated the variability of PM (PM1, PM2.5, and PM10) and their relationship with meteorological parameters in Lagos, Nigeria, using a low-cost embedded monitoring system. Data were collected continuously over a two-year period (May 2021–April 2023) at two-minute intervals, providing one of the longest continuous PM datasets reported for Lagos. Results revealed distinct diurnal and seasonal patterns, with concentrations consistently higher at night and during the dry season. Temperature, relative humidity, atmospheric pressure, and wind speed showed significant inverse relationships with PM across all size fractions, with humidity and wind speed emerging as the strongest predictors. However, regression analysis indicated modest explanatory power (R² = 0.280 for PM2.5 and R² = 0.201 for PM10), suggesting that local emission sources have a dominant influence. Comparison with air quality benchmarks showed substantial exceedances. The daily mean concentration of PM2.5 (37.39 µg/m³) exceeded the WHO 24-hour guideline (15 µg/m³) and marginally exceeded the U.S. NAAQS limit (35 µg/m³). In contrast, PM10 (43.88 µg/m³) remained below the WHO guideline (45 µg/m³) and well within the Nigerian NESREA 24-hour limit (150 µg/m³). The study is limited by its single-site design, which may constrain spatial generalization. Nonetheless, the findings highlight elevated health risks from fine particulates in Lagos and demonstrate the effectiveness of low-cost embedded systems for long-term urban air quality assessment, supporting their integration into regulatory and public health strategies.
Seasonal Dynamics in Heavy Metal Pollution and Environmental Risk in Surface Soils Near a Battery Recycling Plant in Ogijo, Southwestern Nigeria
The study assessed seasonal variations in heavy metal pollution and ecological risk in surface soils around a spent‑battery recycling plant in Ogijo, south-western Nigeria. Forty topsoil samples (0–15 cm) were collected for two seasons and analyzed for Mn, Fe, Cu, Zn, Pb, Co, Cd, Cr and Ni using Atomic Absorption Spectrophotometry. Contamination factor, geoaccumulation index, enrichment factor and ecological risk index were calculated. The standard toxic‑response factors and correlations were used to identify common sources. Most heavy metals (Cu, Zn, Pb, Cr, Ni) occurred below their soil background levels, whereas Cd was greatly elevated in both seasons (16.69mg/kg wet; 6.24mg/kg dry vs 0.3mg/kg background), and Co was moderately enriched in the dry season. Wet‑season indices classified Cd as extremely polluted (CF = 55.6; IGEO > 5), with EF many orders of magnitude above unity and ERI ≈ 1669, while other metals had CF < 1 and ERI < 5, indicating low risk. In the dry season, Cd remained the dominant pollutant (CF = 20.8; ERI ≈ 624) and Co showed CF slightly above 1, but all other metals stayed within the low‑risk range. Correlation matrices revealed strong, significant associations among Cu, Zn, Ni, Cd, Fe and Pb in the wet season, consistent with a common anthropogenic source and hydrological mixing, whereas dry‑season correlations were weaker and more heterogeneous. Overall, soils near the facility are ecotoxicologically dominated by Cd, particularly in the wet season, indicating the need for stricter control of recycling activities, targeted remediation and continuous monitoring.