Physical Science International Journal

Design and Construction of Remote Control Gate Cross Bar

M. E. Ishaje, N. A. Akonjom, E. O. Obi, B. Yahweh — Sat, 01 Aug 2026 00:00:00 +0000

Manual operation of barriers at access points can increase operator workload and may delay vehicular movement. This study designed, constructed, and evaluated a remote-controlled gate cross bar intended to provide a low-cost wireless alternative for automated access control. The system integrated an Arduino Uno microcontroller based on the ATmega328P, a 433 MHz radio-frequency transmitter and receiver, a 12 V DC geared motor, a motor-driver module, limit switches, relay control, status indicators, and a mechanical barrier arm. The control program processed remote commands, activated bidirectional motor movement, and used limit-switch feedback to stop the barrier at the fully open and closed positions. Performance was evaluated under outdoor conditions using 20 opening-and-closing cycles. The measured parameters included response time, opening time, closing time, remote operating range, and operational consistency. The system recorded a mean response time of 0.61 ± 0.05 s, a mean opening time of 2.43 ± 0.08 s, and a mean closing time of 2.48 ± 0.07 s. Stable RF communication was maintained over an average distance of 25 ± 1.2 m. Temporary electromagnetic interference, metallic obstacles, reinforced-concrete walls, and minor power-supply fluctuations affected signal reception or motor speed during some observations. No mechanical failure, motor overheating, excessive vibration, or structural deformation was reported during testing. The developed prototype demonstrated the practical integration of locally available mechanical and electronic components for wireless gate operation, although further evaluation under broader field conditions is required.

Geoeffectiveness of Interplanetary Storm Drivers during Solar Cycle 25 through June 2026: A Comparative Study of ICMEs, Sheath Regions, and Corotating Interaction Regions

Praveen Tyagi, V. K. Mishra — Fri, 07 Aug 2026 00:00:00 +0000

This study presents a cycle-to-date classification and geoeffectiveness analysis of the interplanetary drivers of geomagnetic storms during Solar Cycle 25 (SC25), from December 2019 to 24 June 2026. Hourly OMNI solar-wind plasma and interplanetary magnetic-field data were analysed together with the Dst, Kp, and AE indices. A total of 111 storms with minimum Dst <= -50 nT were identified and assigned to interplanetary coronal mass-ejection (ICME) ejecta or magnetic clouds, sheath regions, combined sheath-plus-ejecta (S+E) structures, or corotating interaction region/high-speed-stream (CIR/HSS) drivers. The catalogue contains 86 moderate, 19 intense, five superintense, and one extreme storm. S+E structures account for 65 storms and 23 of the 25 storms at intense or stronger levels (92%), including all six superintense-or-extreme events. CIR/HSS storms (n = 28) are almost exclusively moderate. Across the full sample, minimum Dst is most strongly associated with peak southward IMF Bz (r = 0.85) and maximum dynamic pressure (|r| = 0.80); the Bz-Dst relationship is tighter for S+E events (r = 0.87) than for CIR/HSS events (r = 0.52). The relative CIR/HSS contribution increases during the declining phase, while ICME-related activity remains substantial. A constant-coefficient linear Burton-type model provides limited pooled hindcast skill, particularly for CIR/HSS storms. A nonlinear threshold-injection formulation with driver-dependent decay scaling, calibrated on pre-2025 storms and evaluated on 2025-2026 storms, yields correlations of r = 0.86-0.91 and prediction efficiencies of 0.74-0.81 across the principal driver classes. Storm-level cross-validation and sensitivity testing indicate that these cycle-to-date conclusions are not driven by a single fitting split or by the uncertain classification of moderate storms. Because the analysis concerns one incomplete solar cycle and relatively few extreme events, the inferred S+E dominance should be treated as an SC25-specific finding requiring confirmation across additional cycles.

Analytical Investigation of Energy and Mass Transport in Magnetohydrodynamic Fe₃O₄–Water Nanofluid Flow through a Chemically Reacting Porous Channel with Thermal Radiation

Ojo, Adetoye Solomon, Nwabuzor, Peter Onyelukachukwu — Mon, 10 Aug 2026 00:00:00 +0000

Magnetohydrodynamic (MHD) nanofluids have emerged as promising working fluids for advanced thermal management systems owing to their enhanced heat transfer capability and controllable transport characteristics under external magnetic fields. This study presents an analytical investigation of coupled energy and mass transport in Fe₃O₄–water nanofluid flow through a chemically reacting porous rectangular channel under the influence of thermal radiation. The novelty of the present work lies in the integration of established thermophysical property correlations for effective viscosity, thermal conductivity, and electrical conductivity with an analytical Laplace transform framework to investigate the combined effects of magnetic field, buoyancy, thermal radiation, nanoparticle volume fraction, and chemical reaction on transport phenomena in porous media. The governing momentum, energy, and concentration equations are formulated using the Buckingham π theorem to obtain the corresponding dimensionless model and are solved analytically using the Laplace transform technique, subject to the prescribed boundary conditions. The developed analytical solutions are employed to examine the influence of the governing dimensionless parameters on the velocity, temperature, and concentration distributions. The analytical results demonstrate that variations in nanoparticle volume fraction significantly modify the thermal and concentration fields through changes in the effective thermophysical properties of the Fe₃O₄–water nanofluid, while an increase in effective viscosity alters fluid momentum transport. The Hartmann number acts as a resistive parameter that suppresses the velocity profile through the Lorentz force, whereas the effects of thermal radiation and chemical reaction on the transport fields are shown to be consistent with the governing equations and the validated analytical solutions. Representative analytical results indicate that changes in the governing parameters produce measurable variations in the velocity, temperature, and concentration distributions under the investigated operating conditions. The proposed analytical model provides improved physical insight into coupled magnetohydrodynamic heat and mass transfer in chemically reacting porous media and offers a reliable theoretical framework for validating numerical models and supporting the design and optimisation of electronic cooling systems, porous thermal devices, energy conversion systems, and other engineering applications employing Fe₃O₄–water nanofluids.

Phase Change Materials for Passive Cooling of Sahelian Buildings: Integration Options and a Screening Assessment for Niger

Moumouni Guero Mohamed, Mousbahou Mahamane Nana Farida — Wed, 19 Aug 2026 00:00:00 +0000

Aims: The study aims to synthesise phase change material (PCM) classification and building-envelope integration techniques relevant to hot, arid climates, and to carry out a comparative techno-economic and environmental assessment of three candidate PCMs (a paraffin, a hydrated salt, and a water-urea eutectic) for passive thermal regulation of housing in Niger.

Study Design: Structured literature synthesis combined with a multi-criteria scoring assessment adapted from established PCM-selection methodology.

Methodology: Published thermophysical, economic and environmental data for the three PCMs were consolidated from the underlying laboratory/simulation study and cross-checked against the wider PCM building-envelope literature. Five techno-economic criteria (cost-effectiveness, durability, ease of maintenance, local availability, thermal stability) and five environmental criteria (embodied energy, carbon footprint, biodegradability, end-of-life recyclability, environmental risk) were each scored from 1 (least favourable) to 5 (most favourable) and combined into an unweighted composite index; an annualised areal cost was additionally computed from unit price, indicative areal loading and expected service life.

Results: Niger's electricity access rate (about 20% in 2023) is far below the sub-Saharan African average (about 53%) and the global figure (about 92%), underlining the case for passive rather than mechanical cooling. The water-urea eutectic scored highest on the techno-economic index (3.9/5) and on the environmental index (4.6/5), driven by low cost and local sourceability, but had the shortest expected service life (5-10 years); paraffin scored lowest on cost-effectiveness and on the environmental index (1.9/5) despite the best durability and thermal stability scores; the hydrated salt occupied an intermediate position throughout. Annualised areal cost, however, favoured paraffin's long service life enough to narrow the gap with water-urea considerably.

Conclusion: No single material dominates across all criteria, which argues against a one-size-fits-all recommendation. Paraffin suits applications where dynamic thermal performance and longevity are prioritised and where the budget allows; the water-urea eutectic suits cost- and carbon-constrained, shorter-horizon retrofits using locally available inputs; and the hydrated salt is a reasonable compromise where corrosion risk can be managed. These results give Nigerien designers and policymakers a first quantitative, climate-specific basis for PCM selection, ahead of the full life-cycle assessments that scaled deployment will eventually require.

Designing of Low-cost Acoustic Analyzer Device with Arduino for Monitoring Hydropower Generator

Thu, 27 Aug 2026 00:00:00 +0000

Low-cost acoustic monitoring can support condition-related data collection for hydropower generators where commercial instruments may be costly or difficult to deploy. This study developed an acoustic acquisition and monitoring arrangement using a KY-038 sound sensor, a parabolic reflector, and an Arduino Mega 2560 architecture for a 15 MW Kaplan hydroturbine alternator. Approximately 100 measurements were collected in each of three defined alternator sectors during normal operation. The sensor output was converted from analogue voltage to pressure and sound level for recording and interpretation. The measurements showed a spatial increase in sound level with proximity to the rotor. Reported average levels for the non-pressed configuration were approximately 73.05 dB in the cooling region, 75.83 dB in the air-gap region, and 79.05 dB near the rotor. With the reflector pressed against the measurement location, the reported sector averages were 74.24, 76.27, and 80.69 dB, respectively. The two acquisition configurations therefore showed a similar spatial pattern, while the pressed configuration produced slightly higher measured levels. These findings indicate that consistent sensor position and contact are important for repeatable baseline acoustic mapping. The proposed low-cost arrangement provides a practical basis for repeated monitoring under comparable operating conditions. However, measurements were not obtained under confirmed fault conditions, and the parabolic-reflector mounting technique requires further improvement and validation.

Geochemical Fractionation, Mobility and Environmental Risk of Lead, Cadmium and Zinc in Agricultural Soils from an Abandoned Mining Area in Jos-South, Nigeria

Thu, 03 Sep 2026 00:00:00 +0000

The total amount of a potentially toxic element in soil, on its own, provides limited information about its mobility or bioavailability. This paper re-examines the geochemical partitioning, extractability and environmental status of lead (Pb), cadmium (Cd) and zinc (Zn) in agricultural soils surrounding abandoned mining excavations at Dahwol-Vwana village, Jos-South Local Government Area, Plateau State, Nigeria. Soil collected around three disused mining holes was subjected to a modified Tessier sequential extraction scheme, which splits Pb, Cd and Zn into an exchangeable-plus-carbonate fraction, a reducible (Fe/Mn oxide-bound) fraction, an oxidisable (organic-matter/sulphide-bound) fraction, and a residual fraction, with each fraction quantified by atomic absorption spectrometry. The results show that Pb, Cd and Zn were predominantly associated with the less mobile fractions: roughly 71.5% of Pb and 81.8% of Cd occurred in the residual fraction, while 89.8% of Zn was bound to organic matter. The exchangeable-plus-carbonate pool accounted for only 7.8% of Pb and 7.5% of Cd, and the oxide-bound (reducible) pool for 12.7% of Pb and 6.5% of Cd; for Zn, the reducible pool accounted for about 3.5% and the residual fraction just 2.9%. Calcium-chloride extractability was correspondingly low, at 3.95–7.30 mg kg⁻¹ for Zn, 3.85–9.59 mg kg⁻¹ for Pb and 0.09–0.44 mg kg⁻¹ for Cd equivalent to extractable proportions of only 0.03–0.05% (Zn), 0.05–0.12% (Pb) and 0.03–0.14% (Cd) of the total inventory. Enrichment factors were 5.6, 15.4 and 2.1 for Pb, Cd and Zn respectively, with corresponding geoaccumulation indices of 1.9, 3.4 and 0.5. Cd therefore combines strong apparent enrichment and a high geoaccumulation classification with a fractionation profile dominated by the residual phase and very low extractability, implying limited immediate mobility despite that enrichment. Overall, the fractionation pattern points to a substantial lithogenic contribution to the metal inventory, though shifts in soil pH, redox status, organic-matter turnover or physical disturbance could still alter mobility over time. The results demonstrate why total-metal concentration should be interpreted alongside chemical fractionation and extractability when environmental risk is being assessed in agricultural soils affected by historical mining.

Experimental Performance Evaluation of a Low-Cost Cylindrical Solar Concentrator for Thermal Cooking Applications in a Tropical Climate

Prince Abdoul Aziz Honadia, Bouto Kossi Imbga, Thierry Sikoudouin Maurice Ky — Mon, 07 Sep 2026 00:00:00 +0000

Access to clean and affordable cooking energy remains a challenge in developing regions, particularly in sub-Saharan Africa, where traditional biomass fuels are widely used and are associated with environmental and health concerns. Solar cooking provides a renewable alternative; however, the practical application of low-cost cylindrical solar concentrators for cooking under fluctuating tropical weather conditions remains insufficiently evaluated. This study presents the design and experimental performance evaluation of a low-cost, manually tracked cylindrical solar concentrator intended for cooking applications. The concentrator features an aluminium reflector with a 1.2 m² aperture area and a geometric concentration ratio of 12. Experimental tests conducted during the rainy season under fluctuating solar irradiance assessed the system's thermal performance using water and cottonseed oil as heat-transfer fluids. The system achieved maximum fluid temperatures of 130 °C for oil and 67 °C for water. The calculated average thermal efficiencies for oil during separate tests were 15.32% and 21.12%, while those for water ranged from 12.04% to 19.86%. In the context of sub-Saharan Africa, these technologies offer a viable solution for achieving cooking temperatures ranging from 150 °C to 300 °C while helping to reduce deforestation. The results demonstrate that, despite suboptimal weather conditions, the cylindrical solar concentrator exhibits a significant capacity for solar-to-heat conversion, supporting its potential as a viable and sustainable cooking solution. Further design improvements and testing during the dry season are recommended to optimise performance.

Lead, Cadmium and Zinc in Agricultural Soils and Irish Potatoes around an Abandoned Tin-Mining Area of Jos-South, Nigeria

Tue, 08 Sep 2026 00:00:00 +0000

Decades of tin extraction on the Jos Plateau have left behind heavily reworked ground, including open pits, spoil heaps and slurry deposits, much of which has gradually been absorbed back into local farming. This paper re-examines a field investigation of that reclamation process, focusing on how much lead (Pb), cadmium (Cd) and zinc (Zn) have built up in the farm soils and Irish potato (Solanum tuberosum) tubers grown around three disused mining excavations at Dahwol-Vwana village, Kuru District, Jos-South Local Government Area, Plateau State. Paired soil and tuber samples were drawn from fifteen points encircling the excavations, with soil taken 10–20 cm beneath the surface of established potato ridges; a comparatively undisturbed site supplied the control material. After wet-acid digestion, metal content was determined by atomic absorption spectrometry (AAS). Soil concentrations spanned 0.0445–3.9343 mg kg⁻¹ for Pb, 0.0086–0.1200 mg kg⁻¹ for Cd and 0.0751–39.0302 mg kg⁻¹ for Zn, while tuber concentrations spanned 0.0741–1.5042, 0.0081–0.0931 and 0.1038–88.0503 mg kg⁻¹, respectively. Every soil sample remained below the international guideline values used for comparison, yet all three metals were consistently higher than in the control soil. Measured against the food-safety benchmarks adopted in the source study, tuber Cd remained within limits throughout, whereas Pb exceeded 0.1 mg kg⁻¹ in eleven of twelve tuber samples and Zn exceeded 15 mg kg⁻¹ in four samples. Taken together, the findings suggest that although the bulk soils were not heavily contaminated by the standards applied, localised enrichment of Pb and Zn in the edible tuber tissue is sufficient to justify continued monitoring of food crops raised on reclaimed mine land.

Post-commissioning Radiological Assessment of Soil and Water Around Dangote Refinery, Lagos, Nigeria

Tue, 08 Sep 2026 00:00:00 +0000

A post-commissioning radiological assessment was conducted to evaluate the radiological status of soil and water in three host communities, Idaso, Ilege, and Mobido, located around the Dangote Petroleum Refinery in Ibeju-Lekki, Lagos, Nigeria. Seven composite soil samples and three composite water samples were collected and analysed by gamma-ray spectrometry using a 3″ × 3″ NaI(Tl) detector. The activity concentrations of naturally occurring Potassium – 40 (⁴⁰K), Uranium -238 (²³⁸U) and Thorium -232 (²³²Th) were determined, and selected radiological parameters, including absorbed dose rate, annual effective dose, radium equivalent activity, external hazard index and annual ingestion dose, were evaluated. Mean soil activity concentrations (Bq/kg) were 191.29 ± 11.74, 16.17 ± 5.13 and 14.53 ± 3.78 for ⁴⁰K, ²³⁸U and ²³²Th, respectively, all below the corresponding UNSCEAR reference values. In water, mean activity concentrations (Bq/L) were 71.73 ± 14.76, 4.45 ± 3.53 and 2.04 ± 0.97 for ⁴⁰K, ²³⁸U and ²³²Th, respectively. The mean absorbed dose rate for soil and the corresponding mean annual effective dose were 24.22 nGyh^-1 and 0.030 mSvy^-1, respectively. The mean radium equivalent activity in soil was 51.68 Bq/kg and the mean external hazard index was 0.140, indicating a low external gamma-radiation hazard. However, the total annual ingestion dose due to water intake from ²³⁸U and ²³²Th ranged from 0.277 to 0.770 mSvy^-1, with a mean of 0.489 mSvy^-1, exceeding the 0.1 mSvy^-1 reference criterion. The findings indicate that the post-commissioning radiological status of the study area is generally within the evaluated reference levels for external exposure, but the elevated ingestion dose estimates warrant continued monitoring and further assessment of radionuclide contributions in water.

Heavy-metal Contamination of Soils and Water in the Apkai and Umusedege Oil-field Communities, Ndokwa East and Ndokwa West, Delta State, Nigeria

Tue, 08 Sep 2026 00:00:00 +0000

Petroleum exploration and production can introduce potentially toxic metals into the soils and water bodies of host communities, with consequences for both ecosystem integrity and human exposure. This study assessed the concentrations and distribution of ten heavy metals: Ni, Cr, Cu, Co, Pb, Cd, Fe, Mn, As and Zn in soil and water from two oil-field communities, Apkai (Ndokwa East Local Government Area) and Umusedege (Ndokwa West Local Government Area), Delta State, Nigeria. A total of 63 soil samples and 11 water samples were collected across the two communities and a nearby control site (Obetim). Soil metals were determined by atomic absorption spectrophotometry (AAS) and, for Zn, Fe and Cu, cross-checked by X-ray fluorescence (XRF); water metals were determined by AAS alone. Overall mean soil concentrations were 148.58, 254.41, 53.15, 0.16, 229.98, 21.85, 2905.61, 1228.55, 0.58 and 175.87 mg kg⁻¹ for Ni, Cr, Cu, Co, Pb, Cd, Fe, Mn, As and Zn, respectively, with Fe as the dominant element throughout. Relative to the control, Cr, Cu, Co, Pb, Cd, Fe, Mn, As and Zn were all elevated in soil, while Ni was slightly lower; the largest soil enrichment ratios were recorded for Mn (2.10×), As (1.81×) and Cr (1.76×). In water, mean concentrations were 0.14, 0.04, 0.13, 0.35, 0.03, 6.91, 1.25 and 0.30 mg L⁻¹ for Ni, Cr, Cu, Pb, Cd, Fe, Mn and Zn, respectively (Co and As were not detected), with Pb (10.77×) and Zn (10.17×) showing by far the largest enrichment relative to the control. The AAS–XRF comparison showed statistically significant differences for Zn, Fe and Cu (p < 0.05 in all cases); XRF consistently returned higher values than AAS. Measured against the soil guideline values reproduced in the underlying study, Ni, Cr, Cu, Pb, Cd, Fe and Mn all exceeded their respective thresholds, most markedly Mn, Fe, Cd, Cr and Pb; in water, Fe, Pb, Cd, Ni and Mn were flagged as being of particular concern against U.S. EPA, WHO and SON reference values. Taken together, the results indicate substantial, spatially uneven alteration of soil and water metal concentrations in this oil-field environment relative to the surrounding background, consistent with a combination of lithogenic and anthropogenic contributions, and establish a concentration baseline for the pollution-index, fractionation and health-risk assessments that build on this dataset.

Validation and Investigation of Correlations to Determine Daily Mean Values of Climatic Parameters

Tue, 08 Sep 2026 00:00:00 +0000

This study evaluated selected correlation models for estimating daytime profiles of global solar radiation on a horizontal surface and ambient temperature at a measurement site in Ouagadougou, Burkina Faso. Experimental data were collected using a pyranometer, a K-type thermocouple and a data logger installed at Joseph KI-ZERBO University. Measurements were recorded at five-minute intervals during selected days in December, January, March and April, and monthly average daytime profiles were obtained. Two trigonometric correlations previously used in existing literature were first applied to describe the temporal variation of solar radiation and ambient temperature. In addition, Gaussian-type correlations were developed using non-linear regression in MATLAB to represent the measured profiles. For global solar radiation, the literature-based sine model produced coefficients of determination between 0.96 and 0.98, with RMSE values ranging from 36.3 to 51.3 W/m². The proposed Gaussian model produced R² values between 0.96 and 0.98, with RMSE values ranging from 33.0 to 51.0 W/m². For ambient temperature, the literature-based model gave R² values between 0.94 and 0.97 and RMSE values between 0.55 and 0.76 °C, while the Gaussian model gave R² values between 0.96 and 0.98 and RMSE values between 0.37 and 0.63 °C. The results indicate that both approaches describe the measured daytime profiles with acceptable agreement.

Meteorological Variability and Statistical Assessment for Sustainable Solar Photovoltaic Farm Siting and Grid Integration Towards Achieving Sustainable Development Goals in Rivers State, Nigeria

Wed, 09 Sep 2026 00:00:00 +0000

Reliable knowledge of local meteorological variability is a prerequisite for technically sound siting and grid integration of a utility-scale solar photovoltaic (PV) farm. This study statistically analysed eleven years (2015–2025; N = 132 monthly observations) of rainfall amount, rainfall rate, relative humidity and sunshine duration for Rivers State, Nigeria, and translated the results into practical guidance for solar PV development in support of Sustainable Development Goal 7 (Affordable and Clean Energy), Goal 13 (Climate Action) and related goals. Descriptive statistics, one-way analysis of variance (ANOVA), Pearson correlation, ordinary least-squares regression and the non-parametric Mann–Kendall/Sen's-slope trend tests were applied, and regression-based proxy-forecast models for sunshine duration and global horizontal irradiance (GHI) were developed and validated on a 2024–2025 hold-out sample. All four variables showed pronounced and statistically significant seasonal variation (ANOVA p < 0.001) but no statistically significant inter-annual trend over the study period (Mann–Kendall p > 0.05 in all cases), indicating a strongly seasonal but climatologically stable resource base. Sunshine duration averaged 7.68 ± 1.54 h/day (CV = 20.0%) and was strongly and significantly negatively correlated with relative humidity (r = − 0.827) and rainfall amount (r = − 0.723, p < 0.001 in both cases). The best-performing proxy model (sunshine and rainfall jointly predicting GHI) achieved a hold-out R² of 0.802 and MAPE of 3.90%, supporting its use for month-ahead solar-resource forecasting. Using the Angstrom–Prescott relation calibrated for Port Harcourt, estimated GHI averaged 6.03 kWh/m²/day (mean clearness index 0.61), with an indicative mean PV capacity factor of 19.6%, rising above 23% in the December–February dry season and falling to about 17% during the June – October rains. A composite site-suitability index built from the standardised sunshine, rainfall and humidity series identified December–February as the optimal window for civil works, panel installation and peak energy yield, and June–October as the period of highest cloud cover, soiling risk and grid-integration variability. These findings support siting solar PV assets on well-drained upland sites away from flood-prone terrain, sizing inverters and battery/storage buffers to accommodate pronounced wet-season output dips, and scheduling major construction and maintenance during the dry season, which collectively strengthen the technical and economic case for grid-connected solar deployment in Rivers State.

Spatiotemporal Temperature Trends and Hybrid Machine Learning Prediction Across the Coastal Rainforest Zone of Nigeria

E. O. Obi, A. A. Abong, L. O. Okang — Tue, 15 Sep 2026 00:00:00 +0000

This study assessed spatiotemporal temperature trends and machine-learning-based temperature prediction across the coastal rainforest zone of Nigeria. Monthly and annual temperature data for Calabar, Yenagoa, Benin City and Ikeja were obtained from the NASA POWER database for the period 1981–2025. The dataset was processed using descriptive statistics, visual inspection, box plots, Mann–Kendall trend testing and Sen’s slope estimation. Hybrid machine-learning prediction was performed using CNN–LSTM, while RF–SVR model performance was also evaluated using root mean square error and mean absolute error. The results showed statistically significant increasing temperature trends across all four locations. Sen’s slope values were 0.031°C/year for Calabar, 0.026°C/year for Yenagoa, 0.017°C/year for Benin City and 0.024°C/year for Ikeja. The strongest monotonic trend was observed in Calabar, while Benin City recorded the highest overall temperature distribution among the stations. Box-plot analysis indicated relatively narrow temperature variability, reflecting the stable thermal character of the humid rainforest environment. Model evaluation showed that RF–SVR produced lower prediction errors than CNN–LSTM across all locations, with the lowest RF–SVR error recorded for Benin City. Overall, the findings indicate a consistent warming tendency across the coastal rainforest zone and demonstrate the usefulness of combining statistical trend analysis with machine-learning evaluation for regional temperature assessment.

Fe-Doped MoSe\(_2\) Monolayers as High-Temperature Half-Metallic Ferromagnets for 2D Spintronics

N’goye Bre-Junior Kanga, Souleymane Tuo, Boris Irie-Bi, Lalla Btissam Drissi — Tue, 15 Sep 2026 00:00:00 +0000

In this study, the electronic architecture and magnetic phenomena of iron-doped molybdenum diselenide (MoSe2) monolayers are systematically investigated using first-principles density functional theory (DFT). Employing the Quantum ESPRESSO computational package with GGA-PBE functionals and projector augmented-wave (PAW) pseudopotentials, structural and electronic simulations were performed on a 4 × 4 × 1 supercell featuring a substitutional Fe doping concentration of 12.5%. While pristine MoSe₂ is inherently a non-magnetic semiconductor, our spin-polarised calculations reveal that the introduction of transition-metal impurities induces a robust half-metallic ferromagnetic ground state. Specifically, the majority-spin channel exhibits strong metallic conduction, while the minority-spin channel maintains a distinct forbidden energy gap of 0.651 eV, yielding 100% spin polarisation at the Fermi level. This transition is fundamentally driven by localised exchange interactions and strong orbital hybridisation between the Fe 3d and host Se 4p states. The substituted lattice achieves a macroscopic total magnetic moment of 4.32 \(\mu\)B per supercell, confirming the establishment of a stable ferromagnetic network. Furthermore, mapping the calculated exchange energy (62.92 meV) onto the classical Heisenberg spin model yields a mean-field estimate of the Curie temperature of approximately 487 K. By coupling above-room-temperature thermal stability with half-metallicity, this investigation highlights the potential of Fe-doped 2D MoSe2 for integration into next-generation nanoscale spintronic applications and advanced magnetic memory architectures.

A Study of a Novel Hydrazone Derivative in the Inhibition of Corrosion of Mild Steel in a HCl Acidic Medium

Fri, 18 Sep 2026 00:00:00 +0000

The inhibition of the corrosion of mild steel was studied via the weight loss method over a period of 30 days in an acidic medium formed by 1.0 M HCl and also through potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). In the weight loss approach, the weight loss of the mild steel exposed to the acidic medium, the evaluation of the inhibition efficiency of the (1E,8E)-9-(3-bromo-4-methoxyphenyl)-1,8-bis(2-(2,4-dinitrophenyl)hydrazone)-3,3,6,6-tetramethyl-1,2,3,4,5,6,7,8,9,10-decahydroacridine, a novel hydrazone derivative and the determination of the corrosion rate thereof were carried out. The loss of weight increased with the length of time that the samples were exposed to the acidic medium, with the total weight loss of 12.190 g, 4.208 g, 7.408 g,11.226 g recorded for the corrosive medium that had no inhibitor and those that had 2 ppm, 6 ppm and 10 ppm of the inhibitor respectively. The percent inhibition efficiency was highest in the acidic medium that had 2 ppm concentration and then decreased as the concentration increased. The highest inhibition efficiency value determined was 69.44 % after 15 days exposure to 1.0 M HCl containing just 2 ppm of the inhibitor. The corrosion rate showed same diminishing values with increasing concentration confirming that the inhibitive capacity of the organic inhibitor compound is dose dependent. From the PDP methodology, a very high corrosion rate of 1.416 × 10³ mpy and corrosion current density (i_corr) of 3100 µA/cm² were noted for the corrosion test without the inhibitor. With the inhibitor, the corrosion rate and corrosion current density (i_corr) significantly reduced to 604.7 mpy and 965 mpy as well as 1320 µA/cm² and 2110 µA/cm², for 2 ppm and 10 ppm inhibitor concentrations respectively. This indicated an effective suppression of the electrochemical reactions responsible for mild steel corrosion. From the EIS methodology, the blank solution exhibited a relatively low R_ct value of 36.49 Ω, indicating a highly aggressive environment. However, these values increased significantly to 136.8 Ω and 43.41 Ω in the corrosion medium with 2 ppm and 10 ppm inhibitor concentration respectively, confirming an impeding of corrosion. All the methods used in evaluating C₃₆H₃₆BrN₉O₉as an inhibitor of mild steel corrosion confirmed a moderate inhibition efficiency at the concentration of 2 ppm, which diminished in all the cases as the concentration was increased to 10 ppm.

Assessment of the Relationship between Meteorological Parameters and Crop Yield in Sokoto and Kano States, Nigeria: A Comparative Analysis

Sat, 19 Sep 2026 00:00:00 +0000

This study assesses the relationship between key meteorological parameters and crop yield in Kano and Sokoto States, north-western Nigeria. Daily meteorological records of rainfall amount, rainfall rate, minimum and maximum temperatures, and relative humidity for 2022 and 2023 were aggregated to monthly and seasonal scales and compared with crop-performance data, including households reporting, planted and harvested areas, harvested quantity, and yield for maize, rice, sweet potato, yam and cowpea. Meteorological data were obtained from the 2022/2023 National Agricultural Sample Survey (NASS) and the Nigerian Meteorological Agency (NiMet). Descriptive statistics and Pearson correlation analysis were used to characterise the meteorological regime of each state and to examine inter-variable relationships. Results show that Sokoto recorded higher rainfall totals in both years (1,349.5 mm in 2022 and 938.1 mm in 2023) than Kano (828.1 mm and 696.4 mm, respectively), a pattern consistent with the unusually heavy 2022 rainy season recorded across the Sokoto–Rima basin and much of Nigeria. Monthly rainfall and relative humidity were strongly and significantly positively correlated in both states (Kano: r = 0.953, p < 0.001; Sokoto: r = 0.923, p < 0.001), while rainfall was negatively associated with maximum temperature, significantly so in Sokoto (r = −0.602, p = 0.038). Agricultural data showed that Sokoto achieved higher major-season yields than Kano for maize (1,973 vs 1,412 kg/ha), rice (1,936 vs 1,575 kg/ha) and sweet potato (2,273 vs 1,818 kg/ha), broadly mirroring its higher seasonal rainfall, whereas Kano showed substantially greater minor (dry)-season cropping activity, consistent with its more extensive irrigation infrastructure. The findings indicate that rainfall amount and relative humidity were important meteorological characteristics associated with agricultural productivity, while also highlighting the influence of irrigation and other non-meteorological factors. The study demonstrates the value of combining meteorological data with agricultural survey data for local-level food-security planning

Seasonal Structure Outweighs Daily Meteorological Associations in Tropospheric Formaldehyde over Abidjan, West Africa

Sat, 19 Sep 2026 00:00:00 +0000

Tropospheric formaldehyde (HCHO) is a short-lived oxidation product of methane and non-methane volatile organic compounds and is widely used as a satellite indicator of VOC oxidation. In single-year satellite records, HCHO and meteorological variables may covary because both follow the annual cycle, potentially confounding interpretation. We analysed 205 Sentinel-5P/TROPOMI HCHO observations over Abidjan, Côte d’Ivoire, in 2024 and matched them to daily maximum temperature, relative humidity, precipitation, and wind speed from ERA5, MERRA-2, CHIRPS, and NASA/POWER. Mean HCHO was 1.783 × 10⁻⁴ mol m⁻² (95% CI: 1.641–1.925 × 10⁻⁴), with a coefficient of variation of 57.8%. HCHO differed strongly among climatic seasons (Kruskal–Wallis H = 61.27, p = 3.14 × 10⁻¹³, ε² = 0.290) and months (H = 82.60, p = 4.63 × 10⁻¹³, ε² = 0.371). In a meteorology-only model, ERA5 maximum temperature remained significant and the model explained 16.1% of daily variance. After adjustment for season, however, the temperature coefficient decreased to 0.026 × 10⁻⁴ mol m⁻² °C⁻¹ (p = 0.595), while meteorology increased R² by only 0.013 beyond the season-only model. Adjustment for month yielded the same interpretation. These results show that shared temporal regime structure can dominate apparently significant daily meteorological associations. Over Abidjan, the 2024 TROPOMI HCHO record is therefore best interpreted as a seasonally structured indicator of VOC oxidation rather than as a direct isoprene or source-specific proxy.

Natural Radioactivity and Radiological Hazard Assessment of Oil-Field Soils in Apkai and Umusedege Communities, Delta State, Nigeria

Mon, 21 Sep 2026 00:00:00 +0000

Naturally occurring radioactive materials (NORM) in soil constitute an important pathway for human exposure to ionising radiation, particularly in areas affected by petroleum exploration and related environmental disturbance. This study evaluated the activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K, and the associated radiological hazards, in soils from the Apkai and Umusedege oil-field communities of Delta State, Nigeria. Soil samples were analysed by gamma-ray spectrometry using a NaI(Tl) detector housed in a low-background counting system at the Centre for Energy Research and Training, Ahmadu Bello University, calibrated against IAEA reference materials (RGK-1, IAEA-448 and RGTh-1) and counted for 30,000 s. Activity concentrations ranged from 22.743–59.730 Bq/kg for ²²⁶Ra, 17.760–52.860 Bq/kg for ²³²Th and 149–314.037 Bq/kg for ⁴⁰K, with corresponding mean values of 36.102, 50.237 and 251.903 Bq/kg. Relative to the control soil, the mean activities were approximately 2.49, 2.38 and 2.96 times higher for ²²⁶Ra, ²³²Th and ⁴⁰K, respectively, with ⁴⁰K showing the strongest relative enhancement. Against the UNSCEAR worldwide average, mean ²²⁶Ra was only marginally elevated (1.03×), ²³²Th was moderately elevated (1.67×), and ⁴⁰K remained below average (0.63×). The mean absorbed dose rate, annual effective dose and radium equivalent activity were 42.22 nGy/h, 0.076 mSv/y and 91.627 Bq/kg, respectively, corresponding to approximately 72%, 7.6% and 25% of their respective reference values. The mean external hazard index, internal hazard index, representative gamma index and alpha index were 0.247, 0.335, 0.376 and 0.162, all below unity. Estimated total cancer risks were 3.18×10⁻⁶ for adults and 4.32×10⁻⁶ for the whole population, both within the USEPA-adopted acceptable range. Although several radionuclide activities were elevated relative to the control soil, and ²³²Th was elevated relative to the worldwide average, all derived radiological hazard indices remained below their recommended thresholds. The findings indicate measurable enhancement of natural radionuclide activity relative to background, without evidence of unacceptable radiological hazard under the criteria applied, and provide a baseline for continued environmental monitoring of oil-field communities in the Ndokwa region of Delta State.

Seismic, Petrophysical, and Rock-Physics Assessment of Geological CO₂ Storage Potential of Kuro Field, Niger Delta

Sonny Inichinbia, Yikarebogha Yibudongha — Thu, 01 Oct 2026 00:00:00 +0000

This research focuses on the application of geophysics in analysing and evaluating reservoir properties from seismic and well data for potential subsurface geological storage and monitoring of emitted CO₂. The study area is the Kuro field, Greater Ughelli, Niger Delta, and the objectives of this study include effectively placing and utilising geophysics throughout the life cycle of CCS to demonstrate that geophysics plays a fundamental role in site selection and characterising CO₂ storage reservoirs; evaluating reservoir storage capacity; monitoring and verifying injected CO₂ over time; and quantifying and reducing the risk of possible CO₂ leakage. This work integrated 3D geological modelling, seismic interpretation and petrophysical analysis to assess the potential for CO₂ storage in the field. Structural interpretation showed a significant horst structure surrounded by major normal fault structures, forming an efficient structural trap for retaining injected CO₂, together with competent seal formations, specifically a thick shale formation, that can effectively contain CO₂. Petrophysical analysis demonstrated that the reservoir has low shale volume, high effective porosity, low water saturation and adequate permeability favourable for CO₂ injection. Rock physics analysis assisted in inverting the elastic properties obtained from seismic data to estimate the saturation of CO₂ in the reservoir during injection and retention. Modelled reservoir properties revealed significant heterogeneity but considerable capacity to store CO₂. The permeability of the reservoir is estimated at 100-600 mD, with an average of 300 mD. Based on calculations using the pore volume of the grid, density of CO₂, formation volume factor, and storage efficiency coefficients, the estimated capacity for CO₂ storage is 23.6 – 48.5 million tonnes. A spatial analysis of the reservoirs indicated that the central and northwestern portions of the reservoir are the most suitable areas for injection of CO₂ because of their relatively high porosity and net pay thickness.

Phosphonate Metal-Organic Frameworks for Proton Conduction: Design Strategies from Crystalline Intermediates to Processable Membranes

Chinaecherem Tochukwu Arum, Chukwuebuka Ubaka Okafor, Ogechukwu Emelda Chinedum — Sat, 26 Sep 2026 00:00:00 +0000

Phosphonate metal-organic frameworks (MOFs) have emerged as promising alternatives to conventional perfluorosulfonic acid-based proton exchange membranes because of their excellent chemical stability, tunable structures, and efficient proton transport properties. This review examines recent advances in the design of phosphonate MOFs for proton conduction, focusing on the progression from crystalline intermediate-directed synthesis to processable membrane architectures. These frameworks are evaluated against the temperature and humidity windows in which they must operate: 60–90 °C at 80–98% relative humidity for hydrated fuel cell duty and 100–160 °C at low or zero humidity for anhydrous operation. The role of linker chemistry, metal centres, framework topology and hydrogen-bonding networks on conductivity and stability is critically discussed, with special attention to the intermediate-directed crystallisation as a means to control framework order and proton-conduction pathways. Integration into mixed-matrix membranes, pure MOF films and hybrid composites is also evaluated alongside the characterisation methods used to probe proton transport and durability. This evidence is presented in an order-defect-interface paradigm suggesting a small but justifiable gap: No study has combined an intermediate-derived phosphonate framework with chitosan or related precursor-controlled order, defect population, interfacial chemistry and membrane mechanics to one another. Despite significant progress, challenges remain in achieving efficient anhydrous proton conduction, standardised performance evaluation, scalable membrane fabrication, and long-term operational stability. Rational defect engineering, intermediate-directed synthesis and sustainable biopolymer-based fabrication should be combined in future research to bridge the gap between laboratory-scale materials and practical membranes for fuel cells and related electrochemical technologies.