Physics Access
A Journal of Physics and Emerging Technologies
A Publication of the Department of Physics, Kaduna State University, Nigeria.
ISSN Online: 2756-3898
ISSN Print: 2714-500X
ISSN Print: 2714-500X
Physics Access is an international open-access, peer-reviewed journal dedicated to advancing knowledge in physics and related interdisciplinary fields across science, technology, and engineering.
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Open Access
Digital Holographic Interferometry for Ethylene Glycol Quality Control
David E Onsombi, Geoffrey Rurimo, Jack Kihiko, and Stephen M Njoroge
abstract View article PDF
Digital holographic interferometry is a non-contact, full-field optical technique for quantifying sample-induced phase variations in transparent liquids. It offers a non-destructive approach for assessing composition-related changes in ethylene glycol. In this study, a Mach–Zehnder off-axis digital holographic interferometry system was constructed using a 632.8 nm helium–neon laser as the coherent illumination source. The laser output was assessed for power stability, after which the beam was spatially filtered and used to record holograms of pure ethylene glycol and ethylene glycol–water mixtures containing 0.1–80% v/v water. The holograms were reconstructed using Fourier-domain sideband filtering. Using the stabilized reconstructed dataset and literature refractive-index data as an external phase-order constraint, the literature-constrained optical path-difference estimate increased from 1.269 µm at 0.1% v/v water to 778.811 µm at 80% v/v water, demonstrating a concentration-dependent optical response. The developed system provides a proof-of-concept basis for literature-constrained, full-field ethylene glycol composition monitoring.
Open Access
Indoor Radon Concentrations and Associated Radiological Risk in Selected Buildings at South-Eastern...
Kangai Winfred, James M Linturi, Isaac M Kwembur, and Jeremiah M Kebwaro
abstract View article PDF
Radon is a naturally occurring radioactive gas and a major contributor to natural radiation exposure, with prolonged inhalation associated with an increased risk of lung cancer. This study evaluated indoor radon concentrations and associated radiological risks in selected buildings at South-Eastern Kenya University (SEKU), Kenya. Indoor radon concentrations were measured in six selected multi-storey buildings using a calibrated RAD7 electronic radon detector under standardized operating conditions. Measurements were conducted on the lowest floor of each building over 24 hours at each sampling location. Radiological risk parameters, including equilibrium equivalent concentration (EEC), annual effective dose (AED), excess lifetime cancer risk (ELCR), and lung cancer cases per million persons per year (LCC), were estimated using internationally established models and conversion factors. Indoor radon concentrations ranged from 8.18 ± 0.26 to 17.21 ± 0.77 Bq m?³, with a mean of 12.84 ± 0.55 Bq m?³, well below the reference levels recommended by the World Health Organization and the International Commission on Radiological Protection. The corresponding mean EEC, AED, ELCR, and LCC were 5.14 ± 0.22 Bq m?³, 0.3239 ± 0.0140 mSv y?¹, (1.25 ± 0.05) × 10?³, and 5.83 ± 0.25 cases per million persons per year, respectively. These values indicate a low estimated radiological risk for the monitored buildings. Because the measurements were limited to 24-hour active monitoring at six buildings, the findings are interpreted as a short-term baseline assessment rather than an estimate of annual average indoor radon exposure. Periodic and seasonal monitoring is recommended to better characterize long-term exposure variability.
Open Access
Occupational Radiation Dose and Ambient Dose Characterization in Selected Healthcare Facilities in ...
Stanley M Matsitsi, James M Linturi, Jeremiah M Kebwaro, Felix W Omonya, and Onesmus J Mutua
abstract View article PDF
Radiation exposure during diagnostic radiology remains a critical occupational radiation safety concern as the global volume and complexity of medical imaging procedures continue to increase. This study assessed personal dose equivalents received by 14 radiographers in three high-workload hospitals in Kitui County, Kenya. Personal dose equivalents were monitored monthly for three consecutive months using TLD-100 (LiF:Mg,Ti) dosimeters, with readouts performed using the Harshaw 8800 reader system at Kenyatta National Hospital (KNH). Descriptive analysis showed modest inter-hospital variability in occupational doses, which may reflect differences in workload, examination practices, and occupational positioning. The mean monthly personal dose equivalents for Hp(0.07) ranged from 0.112 to 0.246 mSv, while those for Hp(10) ranged from 0.101 to 0.205 mSv. Across all monitored worker-month observations, the pooled mean personal dose equivalents were 0.156 mSv for Hp(0.07) and 0.141 mSv for Hp(10), corresponding to annualized projections of 1.87 and 1.69 mSv y?¹, respectively, assuming comparable exposure conditions throughout the year. Ambient dose-equivalent rates, H*(10), measured in 61 rooms across five selected hospitals, ranged from 0.09 to 0.34 ?Sv·h?¹, with a mean dose-equivalent rate of 0.198 ± 0.026 ?Sv·h?¹. Under an assumed indoor occupancy factor of 0.8, the corresponding annualized ambient dose equivalent ranged from 0.63 to 2.38 mSv·y?¹, with a mean of 1.388 mSv·y?¹. The findings indicate relatively low occupational personal dose equivalents and ambient dose-equivalent rates across the surveyed facilities, although continued occupational monitoring and optimization of radiation-protection practices remain warranted.
Open Access
Integrated Aeromagnetic Structural Mapping and Magnetic Source Depth Estimation of the Kaduna Basem...
Hussaini Abdulkareem, Abdullahi N Khalid, Cyril G Afuwai, Isa Y Hassan, Abdulhadi Danlami, and Mustapha T Lawal
abstract View article PDF
This study presents an integrated aeromagnetic investigation of Kaduna State, northwestern Nigeria, to delineate subsurface structures and estimate magnetic source depths within the Nigerian Basement Complex. Twenty-one high-resolution aeromagnetic datasets were analyzed using Reduction-to-Equator (RTE), Horizontal Gradient Magnitude (HGM), Centre for Exploration Targeting (CET), Euler Deconvolution, and Source Parameter Imaging (SPI). RTE anomalies range from ?121.893 to 68.977 nT, reflecting lithological contrasts and structural features. HGM and CET analyses reveal dominant NE–SW and NW–SE structural trends associated with Pan-African deformation. Euler deconvolution indicates that SI = 1 provides the most coherent solutions, with depths ranging from less than 250 m to greater than 750 m, predominantly between 250 and 500 m. SPI estimates source depths of approximately 85–790 m, with deeper sources concentrated in the northwestern, southeastern, and southern sectors. The spatial correspondence among HGM maxima, CET lineaments, Euler solutions, and SPI-derived depths delineates a fault-controlled structural network and identifies structurally favourable zones for further mineral exploration and ground geophysical investigation. The study demonstrates the effectiveness of integrated aeromagnetic techniques for regional structural mapping and mineral exploration targeting in Precambrian basement terrains.
Open Access
Assessment of Groundwater Quality, Contamination Risk, and Hydrogeochemical Characteristics Around ...
Opeyemi R Omokungbe, Abiola O Ilori, Adetoyosi C Ariyo, Micheal R Olojugba, and Thompson F Ediagbonya
abstract View article PDF
Groundwater contamination from unmanaged dumpsites threatens water quality and public health in many developing countries. This study evaluated the physicochemical properties and contamination risk of groundwater around dumpsites in Okitipupa, Ondo State, Nigeria, during the dry season, January 2025. Sixteen samples were collected from Ayeka, Igodan, Market Area, and Irele Road as the reference site and analyzed for physicochemical parameters using standard methods. Data were analyzed with PCA, Water Quality Index (WQI), and health risk assessment in R and MicroCal Origin. The groundwater was generally acidic, with a pH below the WHO range of 6.5 to 8.5. The Market Area showed elevated electrical conductivity, total dissolved solids, and chloride, indicating strong leachate influence. After excluding phosphate and total suspended solids and verifying standards, WQI values ranged from 64.6 to 117.6. The Market Area had the poorest quality (WQI = 117.6; poor), while Ayeka, Igodan, and Irele Road were classified as good. The non-carcinogenic health-risk assessment, based on the stated reference doses for nitrate and phosphate, yielded HQ and HI values below 1 for adults and children at all locations. The Market Area remained the most impacted site overall, while contamination at the more distant locations suggests additional anthropogenic sources. A limitation is that sampling was limited to the dry season and to physicochemical parameters only.
Open Access
Halide-Induced Band Gap Modulation in RbPbCl3-XBrX Perovskites: Insights from a First-Principles St...
Magaji Ismail
abstract View article PDF
First-principles calculations based on density functional theory (DFT) as implemented in Quantum ESPRESSO were used to systematically investigate the structural and electronic properties of inorganic halide perovskites RbPbCl3-xBrx (x = 0.00, 0.25, 1.50, 2.75, and 3.00). The generalized gradient approximation (GGA) with the Perdew–Burke–Ernzerhof (PBE) functional was employed to describe exchange correlation effects. The optimized lattice parameters reveal that bromine incorporation significantly influences the crystal structure, leading to variations in lattice constants, bond lengths, and unit cell volume due to the difference in atomic radii between Cl and Br atoms. The calculated bulk modulus indicates a reduction in mechanical stiffness with increasing bromine concentration, suggesting enhanced structural flexibility. Electronic band structure analysis shows that all compounds have a direct band gap at the ?-point. Notably, the band gap values obtained were 2.22 eV, 1.87 eV, 1.62 eV, 1.32 eV, and 1.21 eV for RbPbCl3-xBrx (x = 0.00, 0.25, 1.50, 2.75, and 3.00), respectively. The decrease in the band gap becomes prominent as the Br doping concentration increases. This indicates effective band gap tuning via halide substitution. The density of states (DOS) and partial density of states (PDOS) analysis reveal that the valence band is predominantly contributed to by halide p-orbitals, while the conduction band is mainly composed of Pb p-states with minor contributions from Rb states. These findings demonstrate that bromine doping effectively modulates the electronic properties of RbPbCl3, making RbPbCl3-xBrx a promising candidate for optoelectronic and photovoltaic applications.
Open Access
Formation Energy and Phonon Dispersion of Halogen-Doped Rutile TiO2: First-Principles Investigation...
Timothy Bulus, Alhassan Shuaibu, Sadiq A Garba, and Philibus M Gyuk
abstract View article PDF
This study presents a first-principles investigation of the formation energy and phonon dispersion of halogen-doped rutile TiO?. Calculations were performed using density functional theory (DFT) within the generalized gradient approximation (GGA), as implemented in the Quantum ESPRESSO package. A 2 × 2 × 2 supercell containing 48 atoms was constructed, and halogen atoms (F, Cl, Br, and I) were introduced by substituting oxygen atoms, corresponding to a doping concentration of 3.125%. The thermodynamic stability of the doped systems was evaluated through formation energy calculations, which indicate that halogen incorporation is energetically favorable, with stability decreasing in the order F > Cl > Br > I. Structural optimization reveals that lattice distortion increases with the increasing atomic size of the dopant. Phonon dispersion calculations based on density functional perturbation theory (DFPT) confirm the dynamical stability of the doped systems, as evidenced by the absence of imaginary phonon frequencies. Halogen doping also modifies the vibrational properties of TiO?, resulting in systematic frequency shifts arising from differences in dopant mass and bonding characteristics. These findings offer valuable insights into the thermodynamic stability and lattice dynamics of halogen-doped TiO?, highlighting its potential applications in photocatalysis and optoelectronic devices.
Open Access
First-principles Investigation of Structural, Electronic, Mechanical, Optical, and Thermodynamic Pr...
Rose P Abang, Auwalu Musa, Reuben A Solomon, Abdulkadir S Gidado, and Sylvester Hassan
abstract View article PDF
This study employed density functional theory (DFT) within Quantum ESPRESSO to investigate the structural, electronic, phonon, mechanical, optical, and thermodynamic properties of cubic KSrX? (X = F, Cl, Br) halide perovskites for UV optoelectronic applications. All compounds were found to be structurally, thermodynamically, mechanically, and dynamically stable, as confirmed by negative formation energies, appropriate Goldschmidt tolerance factors, Born stability criteria, and phonon spectra without imaginary frequencies. KSrF? exhibited a direct band gap of 5.52 eV, while KSrCl? and KSrBr? showed indirect band gaps of 4.45 and 3.75 eV, respectively, making KSrF? the most promising candidate for deep-UV applications. The compounds exhibited ductile behavior, characterized by dominant ionic bonding, low Debye temperatures indicative of low lattice thermal conductivity, and thermodynamic properties consistent with the third law of thermodynamics and Dulong–Petit’s law. Optical calculations revealed strong UV absorption and static dielectric constants of 2.02, 2.46, and 2.56 for KSrF?, KSrCl?, and KSrBr?, respectively, highlighting their potential for UV optoelectronic devices.
Open Access
An Offline-First Low-Cost Smart Home Automation System Using Bluetooth and Android-Based Voice Cont...
Muhammad I Abdulganiyu, Isaac H Daniel, Alhassan Shuaibu, and Nicodemus Kure
abstract View article PDF
The widespread adoption of Internet of Things (IoT)-based smart home systems has led to
increasing reliance on cloud-dependent architectures that require stable internet connectivity.
However, such dependence restricts deployment in environments with limited or unreliable
network infrastructure. This study presents the design, implementation, and performance
evaluation of an offline-first smart home automation system based on Bluetooth
communication and Android-based voice control. The system integrates a NodeMCU ESP8266
microcontroller, an HC-05 Bluetooth module, and a multi-channel relay interface to enable
localized appliance control without internet dependency. A dual-mode interaction framework
is implemented, supporting both manual control through a graphical user interface and voice-command input using speech recognition. System performance is evaluated in terms of
response time, communication range, packet delivery success rate, power consumption, and
operational stability. Experimental results indicate average response times of 0.3 s and 0.8 s for
manual and voice-control modes, respectively, with stable communication achieved over a 10
m line-of-sight range. Packet delivery success rates of 98.0% and 94.5% were obtained under
line-of-sight and obstructed indoor conditions, respectively, demonstrating reliable command
execution in practical operating environments. The results demonstrate that the proposed
offline-first architecture provides a robust, cost-effective, and infrastructure-independent
solution for localized smart home automation, particularly in resource-constrained
environments.
Open Access
Development and Validation of a MeasurementInformed MATLAB/Simulink Harmonic Propagation Model for ...
Bamaiyi C Daniel, Isaac H Daniel, Mohammed M Aliyu, Abdulkarim L Meyere, and Nicodemus Kure
abstract View article PDF
This study developed and validated a measurement-informed MATLAB/Simulink harmonic
propagation model for a practical 33 kV distribution network using the Ungwan Boro feeder in
Kaduna Metropolis, Nigeria, as the study network. Field-derived feeder characteristics,
transformer impedance, load current profiles, and harmonic spectra were used to parameterise
the model, which incorporated frequency-dependent network impedances, nonlinear loads, and
harmonic current injections. Simulation results revealed pronounced current distortion
dominated by the 3rd, 5th, and 7th harmonics. At the Ardo Substation, the simulated current
total harmonic distortion (THD) of 27.69% compared closely with the measured value of
27.95%, corresponding to a percentage deviation of 0.94%. At the Reg Substation, the
simulated spectrum reproduced the dominant harmonic orders identified in the corresponding
field-derived data. The combined quantitative and spectral agreement demonstrates the model's
ability to reproduce the principal harmonic characteristics of the investigated feeder. The
validated framework provides a measurement-informed computational basis for harmonic
propagation analysis and subsequent investigation of harmonic-related phenomena and
mitigation strategies.
Open Access
Screening-Level Radiological Risk Assessment of Natural Radionuclides in Jabi Lake Sediments Using ...
John K Simon, Sonnie J Oniye, Abrahim G Yisa, Andrew O Agbon, and Abdulsamad Asuku
abstract View article PDF
Naturally occurring radioactive materials (NORMs) in lake sediments may contribute to human
radiation exposure through multiple environmental pathways, making periodic radiological
assessment important for environmental protection. This study conducted a screening-level
radiological risk assessment of Jabi Lake, Abuja, Nigeria, using activity concentrations of
226Ra, 232Th, and 40K measured from a one-time sediment sampling campaign and the
RESRAD-Onsite computer code. Gamma spectrometric analysis showed that the measured
radionuclide concentrations and the corresponding radium equivalent activity were below the
recommended UNSCEAR limits, indicating that the present radiological status of the lake
sediments is unlikely to pose significant health concerns. Conservative RESRAD-Onsite
simulations identified fish consumption as the dominant potential exposure pathway and
indicated increased radiation dose and excess lifetime cancer risk under hypothetical long-term
exposure scenarios assuming persistent radionuclide concentrations. These results represent
conservative screening-level estimates rather than predictions of future environmental
conditions. The study provides baseline radiological data for Jabi Lake and demonstrates the
value of integrating environmental measurements with conservative modelling to support
preliminary risk evaluation and future environmental monitoring.
Open Access
Risk Assessment and Uncertainty Analysis of Radon-222 Concentrations in Groundwater Within Abuja, N...
Blessing C Nwankwo, and Yakubu V Ibrahim
abstract View article PDF
Radon-222 (222Rn) in groundwater is a potential source of internal radiation exposure through ingestion, particularly in regions where groundwater constitutes a major source of drinking water. This study presents an assessment of 222Rn concentrations, radiological risks, and measurement uncertainties in groundwater within Kubwa, Abuja, Nigeria, using liquid scintillation counting. Thirty groundwater samples collected during the peak dry season were analysed using a calibrated Tri-Carb 1000 TR liquid scintillation analyser, with corrections for radioactive decay and partitioning effects. The 222Rn concentrations ranged from below the detection limit to 2.30 Bq L?¹, with a mean of 0.29 ± 0.43 Bq L?¹. Estimated annual effective doses were of the order of 10?³ mSv y?¹, well below the recommended reference level of 0.1 mSv y?¹. Expanded relative uncertainties (k = 2) ranged from approximately 6% for higher-activity samples to over 20% for samples near the detection limit. The results indicate a very low radiological risk from 222Rn ingestion through groundwater and provide baseline data for the study area. The findings also demonstrate the importance of considering detection limits and measurement uncertainty in environmental radioactivity assessments.
Open Access
First-Principles Investigation of Alkaline-Earth Metal Co-Doped Hexagonal WO3 for Enhanced Near-Inf...
Umar Ibrahim, Alhassan Shuaibu, Adamu Muhammed, Yakubu T Aliyu, Musa Lawal, and Timothy Bulus
abstract View article PDF
The structural, thermodynamic, electronic, and optoelectronic properties of co-doped hexagonal tungsten trioxide (h-WO?) are investigated using Density Functional Theory (DFT) with the HSE06 hybrid functional and Density Functional Perturbation Theory (DFPT). To enhance near-infrared (NIR) response, beryllium is paired with alkaline-earth metals (Mg, Ca, Sr, and Ba) to form co-doped hexagonal tungsten bronze-like (h-HTB) configurations. Phonon-dispersion calculations confirm the dynamical stability of the co-doped systems, while formation-energy analysis indicates that the (Be, Ba) configuration is the most thermodynamically favorable, with a minimum formation energy of -2.68 eV. Electronic-structure calculations show that co-doping introduces impurity states within the pristine 3.3 eV band gap, leading to substantial band-gap narrowing across the dopant series. In particular, the (Be, Ba) system exhibits a reduced band gap of 0.9 eV, which is favorable for NIR absorption. Dielectric-function analysis further reveals a crossover in the real part of the dielectric function, ??(?), together with a resonant feature in the imaginary part, ??(?), near 0.9 eV, suggesting possible plasmonic behavior in the low-energy region. The calculated optical absorption spectra show strong NIR absorption with coefficients exceeding 10? cm?¹ and trends comparable to those of Cs?.??WO? benchmark systems, while retaining visible-light transparency. Overall, the results identify (Be, Ba) co-doped h-WO? as a thermodynamically favorable and optically promising candidate for smart-window and photothermal applications.
Open Access
Crystallographic and Spectroscopic Analysis of Activated Carbon Derived from MicrowaveAssisted KOH ...
Mary E Oni, John C Agomuo, Samuel M Udeh, and Salisu I Kunya
abstract View article PDF
KOH-activated carbon was prepared from banana peel waste by microwave heating (800 W) for 10, 20, 30, and 40 min with a constant KOH/precursor ratio of 1:1. The effect of irradiation time on crystal order and surface chemistry was systematically investigated by X-ray Diffraction (XRD) and Raman spectroscopy. XRD analysis showed that crystallinity and graphitization increased gradually with activation time; at 40 min, the crystallite size was 20.5 ± 0.6 nm and the microstrain was 0.00160. Raman spectroscopy showed a systematic evolution of the D/G band intensity ratio (ID/IG) from ~1.0 (carbonized) to a minimum of 0.75 at 30 min, indicative of optimised graphitic ordering. The 30-40 min samples showed the highest degree of graphitization, suggesting potential for enhanced electrical conductivity and charge-storage performance. These results demonstrate that microwave activation duration is a powerful parameter for tuning the structural properties of banana peel-derived activated carbon for energy and adsorption applications.
Open Access
Factors Influencing Households Intention to Adopt Solar Photovoltaic Technology for Net Metering in...
Lottie Singini, Chikumbusko Kaonga , and Christabel Kambala
abstract View article PDF
Adoption of solar photovoltaic (PV) technology is essential for the successful implementation of Malawi's newly introduced net-metering framework. However, evidence on urban household adoption intentions remains limited. This study investigated the sociodemographic and perceptual factors influencing households' intention to adopt solar PV for net-metering in
Mzuzu City, Malawi. A descriptive survey of 182 grid-connected households was conducted, and binary logistic regression, guided by the Theory of Planned Behaviour (TPB) and the Technology Acceptance Model (TAM), was used to identify significant predictors of adoption intention. The regression model was statistically significant (?² = 82.84, p < 0.001), explained
49% of the variation in adoption intention (Nagelkerke R² = 0.49), and correctly classified 80.2% of households. House ownership emerged as the strongest predictor of adoption intention, followed by economic perception, environmental perception, household size, electricity expenditure, gender, and education level, while age, marital status, income source,
and social and technical perceptions were not significant. The findings indicate that household adoption intention is driven primarily by structural characteristics and perceived economic and environmental benefits rather than demographic factors alone. The study further identifies landlord–tenant constraints and regulatory uncertainty as key barriers unique to the netmetering context, providing evidence to guide policies and targeted interventions that can accelerate household participation in Malawi's emerging net-metering programme.
Open Access
Design and Construction of an Ultrasonic Level Measurement Device Using Arduino Uno
Caleb Kambai, and Matthew N Agu
abstract View article PDF
Accurate and reliable level monitoring is essential in many industrial and scientific applications, including water storage, oil and gas processing, agricultural systems, and automated processes. Conventional contact-based measurement techniques are often limited by corrosion, contamination, and environmental effects, which can compromise measurement accuracy and system reliability. This study presents the design, construction, calibration, and performance evaluation of a non-contact ultrasonic level measurement device based on a custom ultrasonic sensing system integrated with an Arduino Uno microcontroller. The device operates on the ultrasonic time-of-flight principle, in which distance is determined from the travel time of reflected sound pulses. The developed prototype was tested over a measurement range of 2.9–400 cm using 51 measurement points, with five repeated readings recorded at each point to evaluate repeatability and measurement uncertainty. Statistical analysis yielded a mean absolute error (MAE) of 0.129 cm, a root mean square error (RMSE) of 0.163 cm, a standard deviation of 0.143 cm, and a coefficient of determination (R²) of 0.999998, demonstrating excellent linearity and measurement accuracy. The percentage error decreased with increasing measurement distance, reaching a minimum of 0.025% at 400 cm, which is attributed to reduced near-field instability and improved ultrasonic wave propagation at longer ranges. The results demonstrate that the developed system provides reliable real-time level measurement under controlled conditions and offers a cost-effective solution for industrial automation, reservoir monitoring, and storage tank applications.
Open Access
Digital Holographic Interferometry for Ethylene Glycol Quality Control
David E Onsombi, Geoffrey Rurimo, Jack Kihiko, and Stephen M Njoroge
abstract View article PDF
Digital holographic interferometry is a non-contact, full-field optical technique for quantifying sample-induced phase variations in transparent liquids. It offers a non-destructive approach for assessing composition-related changes in ethylene glycol. In this study, a Mach–Zehnder off-axis digital holographic interferometry system was constructed using a 632.8 nm helium–neon laser as the coherent illumination source. The laser output was assessed for power stability, after which the beam was spatially filtered and used to record holograms of pure ethylene glycol and ethylene glycol–water mixtures containing 0.1–80% v/v water. The holograms were reconstructed using Fourier-domain sideband filtering. Using the stabilized reconstructed dataset and literature refractive-index data as an external phase-order constraint, the literature-constrained optical path-difference estimate increased from 1.269 µm at 0.1% v/v water to 778.811 µm at 80% v/v water, demonstrating a concentration-dependent optical response. The developed system provides a proof-of-concept basis for literature-constrained, full-field ethylene glycol composition monitoring.
Open Access
Indoor Radon Concentrations and Associated Radiological Risk in Selected Buildings at South-Eastern...
Kangai Winfred, James M Linturi, Isaac M Kwembur, and Jeremiah M Kebwaro
abstract View article PDF
Radon is a naturally occurring radioactive gas and a major contributor to natural radiation exposure, with prolonged inhalation associated with an increased risk of lung cancer. This study evaluated indoor radon concentrations and associated radiological risks in selected buildings at South-Eastern Kenya University (SEKU), Kenya. Indoor radon concentrations were measured in six selected multi-storey buildings using a calibrated RAD7 electronic radon detector under standardized operating conditions. Measurements were conducted on the lowest floor of each building over 24 hours at each sampling location. Radiological risk parameters, including equilibrium equivalent concentration (EEC), annual effective dose (AED), excess lifetime cancer risk (ELCR), and lung cancer cases per million persons per year (LCC), were estimated using internationally established models and conversion factors. Indoor radon concentrations ranged from 8.18 ± 0.26 to 17.21 ± 0.77 Bq m?³, with a mean of 12.84 ± 0.55 Bq m?³, well below the reference levels recommended by the World Health Organization and the International Commission on Radiological Protection. The corresponding mean EEC, AED, ELCR, and LCC were 5.14 ± 0.22 Bq m?³, 0.3239 ± 0.0140 mSv y?¹, (1.25 ± 0.05) × 10?³, and 5.83 ± 0.25 cases per million persons per year, respectively. These values indicate a low estimated radiological risk for the monitored buildings. Because the measurements were limited to 24-hour active monitoring at six buildings, the findings are interpreted as a short-term baseline assessment rather than an estimate of annual average indoor radon exposure. Periodic and seasonal monitoring is recommended to better characterize long-term exposure variability.
Open Access
Occupational Radiation Dose and Ambient Dose Characterization in Selected Healthcare Facilities in ...
Stanley M Matsitsi, James M Linturi, Jeremiah M Kebwaro, Felix W Omonya, and Onesmus J Mutua
abstract View article PDF
Radiation exposure during diagnostic radiology remains a critical occupational radiation safety concern as the global volume and complexity of medical imaging procedures continue to increase. This study assessed personal dose equivalents received by 14 radiographers in three high-workload hospitals in Kitui County, Kenya. Personal dose equivalents were monitored monthly for three consecutive months using TLD-100 (LiF:Mg,Ti) dosimeters, with readouts performed using the Harshaw 8800 reader system at Kenyatta National Hospital (KNH). Descriptive analysis showed modest inter-hospital variability in occupational doses, which may reflect differences in workload, examination practices, and occupational positioning. The mean monthly personal dose equivalents for Hp(0.07) ranged from 0.112 to 0.246 mSv, while those for Hp(10) ranged from 0.101 to 0.205 mSv. Across all monitored worker-month observations, the pooled mean personal dose equivalents were 0.156 mSv for Hp(0.07) and 0.141 mSv for Hp(10), corresponding to annualized projections of 1.87 and 1.69 mSv y?¹, respectively, assuming comparable exposure conditions throughout the year. Ambient dose-equivalent rates, H*(10), measured in 61 rooms across five selected hospitals, ranged from 0.09 to 0.34 ?Sv·h?¹, with a mean dose-equivalent rate of 0.198 ± 0.026 ?Sv·h?¹. Under an assumed indoor occupancy factor of 0.8, the corresponding annualized ambient dose equivalent ranged from 0.63 to 2.38 mSv·y?¹, with a mean of 1.388 mSv·y?¹. The findings indicate relatively low occupational personal dose equivalents and ambient dose-equivalent rates across the surveyed facilities, although continued occupational monitoring and optimization of radiation-protection practices remain warranted.
Open Access
Integrated Aeromagnetic Structural Mapping and Magnetic Source Depth Estimation of the Kaduna Basem...
Hussaini Abdulkareem, Abdullahi N Khalid, Cyril G Afuwai, Isa Y Hassan, Abdulhadi Danlami, and Mustapha T Lawal
abstract View article PDF
This study presents an integrated aeromagnetic investigation of Kaduna State, northwestern Nigeria, to delineate subsurface structures and estimate magnetic source depths within the Nigerian Basement Complex. Twenty-one high-resolution aeromagnetic datasets were analyzed using Reduction-to-Equator (RTE), Horizontal Gradient Magnitude (HGM), Centre for Exploration Targeting (CET), Euler Deconvolution, and Source Parameter Imaging (SPI). RTE anomalies range from ?121.893 to 68.977 nT, reflecting lithological contrasts and structural features. HGM and CET analyses reveal dominant NE–SW and NW–SE structural trends associated with Pan-African deformation. Euler deconvolution indicates that SI = 1 provides the most coherent solutions, with depths ranging from less than 250 m to greater than 750 m, predominantly between 250 and 500 m. SPI estimates source depths of approximately 85–790 m, with deeper sources concentrated in the northwestern, southeastern, and southern sectors. The spatial correspondence among HGM maxima, CET lineaments, Euler solutions, and SPI-derived depths delineates a fault-controlled structural network and identifies structurally favourable zones for further mineral exploration and ground geophysical investigation. The study demonstrates the effectiveness of integrated aeromagnetic techniques for regional structural mapping and mineral exploration targeting in Precambrian basement terrains.
Open Access
Assessment of Groundwater Quality, Contamination Risk, and Hydrogeochemical Characteristics Around ...
Opeyemi R Omokungbe, Abiola O Ilori, Adetoyosi C Ariyo, Micheal R Olojugba, and Thompson F Ediagbonya
abstract View article PDF
Groundwater contamination from unmanaged dumpsites threatens water quality and public health in many developing countries. This study evaluated the physicochemical properties and contamination risk of groundwater around dumpsites in Okitipupa, Ondo State, Nigeria, during the dry season, January 2025. Sixteen samples were collected from Ayeka, Igodan, Market Area, and Irele Road as the reference site and analyzed for physicochemical parameters using standard methods. Data were analyzed with PCA, Water Quality Index (WQI), and health risk assessment in R and MicroCal Origin. The groundwater was generally acidic, with a pH below the WHO range of 6.5 to 8.5. The Market Area showed elevated electrical conductivity, total dissolved solids, and chloride, indicating strong leachate influence. After excluding phosphate and total suspended solids and verifying standards, WQI values ranged from 64.6 to 117.6. The Market Area had the poorest quality (WQI = 117.6; poor), while Ayeka, Igodan, and Irele Road were classified as good. The non-carcinogenic health-risk assessment, based on the stated reference doses for nitrate and phosphate, yielded HQ and HI values below 1 for adults and children at all locations. The Market Area remained the most impacted site overall, while contamination at the more distant locations suggests additional anthropogenic sources. A limitation is that sampling was limited to the dry season and to physicochemical parameters only.
Open Access
Halide-Induced Band Gap Modulation in RbPbCl3-XBrX Perovskites: Insights from a First-Principles St...
Magaji Ismail
abstract View article PDF
First-principles calculations based on density functional theory (DFT) as implemented in Quantum ESPRESSO were used to systematically investigate the structural and electronic properties of inorganic halide perovskites RbPbCl3-xBrx (x = 0.00, 0.25, 1.50, 2.75, and 3.00). The generalized gradient approximation (GGA) with the Perdew–Burke–Ernzerhof (PBE) functional was employed to describe exchange correlation effects. The optimized lattice parameters reveal that bromine incorporation significantly influences the crystal structure, leading to variations in lattice constants, bond lengths, and unit cell volume due to the difference in atomic radii between Cl and Br atoms. The calculated bulk modulus indicates a reduction in mechanical stiffness with increasing bromine concentration, suggesting enhanced structural flexibility. Electronic band structure analysis shows that all compounds have a direct band gap at the ?-point. Notably, the band gap values obtained were 2.22 eV, 1.87 eV, 1.62 eV, 1.32 eV, and 1.21 eV for RbPbCl3-xBrx (x = 0.00, 0.25, 1.50, 2.75, and 3.00), respectively. The decrease in the band gap becomes prominent as the Br doping concentration increases. This indicates effective band gap tuning via halide substitution. The density of states (DOS) and partial density of states (PDOS) analysis reveal that the valence band is predominantly contributed to by halide p-orbitals, while the conduction band is mainly composed of Pb p-states with minor contributions from Rb states. These findings demonstrate that bromine doping effectively modulates the electronic properties of RbPbCl3, making RbPbCl3-xBrx a promising candidate for optoelectronic and photovoltaic applications.
Open Access
Formation Energy and Phonon Dispersion of Halogen-Doped Rutile TiO2: First-Principles Investigation...
Timothy Bulus, Alhassan Shuaibu, Sadiq A Garba, and Philibus M Gyuk
abstract View article PDF
This study presents a first-principles investigation of the formation energy and phonon dispersion of halogen-doped rutile TiO?. Calculations were performed using density functional theory (DFT) within the generalized gradient approximation (GGA), as implemented in the Quantum ESPRESSO package. A 2 × 2 × 2 supercell containing 48 atoms was constructed, and halogen atoms (F, Cl, Br, and I) were introduced by substituting oxygen atoms, corresponding to a doping concentration of 3.125%. The thermodynamic stability of the doped systems was evaluated through formation energy calculations, which indicate that halogen incorporation is energetically favorable, with stability decreasing in the order F > Cl > Br > I. Structural optimization reveals that lattice distortion increases with the increasing atomic size of the dopant. Phonon dispersion calculations based on density functional perturbation theory (DFPT) confirm the dynamical stability of the doped systems, as evidenced by the absence of imaginary phonon frequencies. Halogen doping also modifies the vibrational properties of TiO?, resulting in systematic frequency shifts arising from differences in dopant mass and bonding characteristics. These findings offer valuable insights into the thermodynamic stability and lattice dynamics of halogen-doped TiO?, highlighting its potential applications in photocatalysis and optoelectronic devices.
Open Access
First-principles Investigation of Structural, Electronic, Mechanical, Optical, and Thermodynamic Pr...
Rose P Abang, Auwalu Musa, Reuben A Solomon, Abdulkadir S Gidado, and Sylvester Hassan
abstract View article PDF
This study employed density functional theory (DFT) within Quantum ESPRESSO to investigate the structural, electronic, phonon, mechanical, optical, and thermodynamic properties of cubic KSrX? (X = F, Cl, Br) halide perovskites for UV optoelectronic applications. All compounds were found to be structurally, thermodynamically, mechanically, and dynamically stable, as confirmed by negative formation energies, appropriate Goldschmidt tolerance factors, Born stability criteria, and phonon spectra without imaginary frequencies. KSrF? exhibited a direct band gap of 5.52 eV, while KSrCl? and KSrBr? showed indirect band gaps of 4.45 and 3.75 eV, respectively, making KSrF? the most promising candidate for deep-UV applications. The compounds exhibited ductile behavior, characterized by dominant ionic bonding, low Debye temperatures indicative of low lattice thermal conductivity, and thermodynamic properties consistent with the third law of thermodynamics and Dulong–Petit’s law. Optical calculations revealed strong UV absorption and static dielectric constants of 2.02, 2.46, and 2.56 for KSrF?, KSrCl?, and KSrBr?, respectively, highlighting their potential for UV optoelectronic devices.
Open Access
An Offline-First Low-Cost Smart Home Automation System Using Bluetooth and Android-Based Voice Cont...
Muhammad I Abdulganiyu, Isaac H Daniel, Alhassan Shuaibu, and Nicodemus Kure
abstract View article PDF
The widespread adoption of Internet of Things (IoT)-based smart home systems has led to
increasing reliance on cloud-dependent architectures that require stable internet connectivity.
However, such dependence restricts deployment in environments with limited or unreliable
network infrastructure. This study presents the design, implementation, and performance
evaluation of an offline-first smart home automation system based on Bluetooth
communication and Android-based voice control. The system integrates a NodeMCU ESP8266
microcontroller, an HC-05 Bluetooth module, and a multi-channel relay interface to enable
localized appliance control without internet dependency. A dual-mode interaction framework
is implemented, supporting both manual control through a graphical user interface and voice-command input using speech recognition. System performance is evaluated in terms of
response time, communication range, packet delivery success rate, power consumption, and
operational stability. Experimental results indicate average response times of 0.3 s and 0.8 s for
manual and voice-control modes, respectively, with stable communication achieved over a 10
m line-of-sight range. Packet delivery success rates of 98.0% and 94.5% were obtained under
line-of-sight and obstructed indoor conditions, respectively, demonstrating reliable command
execution in practical operating environments. The results demonstrate that the proposed
offline-first architecture provides a robust, cost-effective, and infrastructure-independent
solution for localized smart home automation, particularly in resource-constrained
environments.
Open Access
Development and Validation of a MeasurementInformed MATLAB/Simulink Harmonic Propagation Model for ...
Bamaiyi C Daniel, Isaac H Daniel, Mohammed M Aliyu, Abdulkarim L Meyere, and Nicodemus Kure
abstract View article PDF
This study developed and validated a measurement-informed MATLAB/Simulink harmonic
propagation model for a practical 33 kV distribution network using the Ungwan Boro feeder in
Kaduna Metropolis, Nigeria, as the study network. Field-derived feeder characteristics,
transformer impedance, load current profiles, and harmonic spectra were used to parameterise
the model, which incorporated frequency-dependent network impedances, nonlinear loads, and
harmonic current injections. Simulation results revealed pronounced current distortion
dominated by the 3rd, 5th, and 7th harmonics. At the Ardo Substation, the simulated current
total harmonic distortion (THD) of 27.69% compared closely with the measured value of
27.95%, corresponding to a percentage deviation of 0.94%. At the Reg Substation, the
simulated spectrum reproduced the dominant harmonic orders identified in the corresponding
field-derived data. The combined quantitative and spectral agreement demonstrates the model's
ability to reproduce the principal harmonic characteristics of the investigated feeder. The
validated framework provides a measurement-informed computational basis for harmonic
propagation analysis and subsequent investigation of harmonic-related phenomena and
mitigation strategies.
Open Access
Screening-Level Radiological Risk Assessment of Natural Radionuclides in Jabi Lake Sediments Using ...
John K Simon, Sonnie J Oniye, Abrahim G Yisa, Andrew O Agbon, and Abdulsamad Asuku
abstract View article PDF
Naturally occurring radioactive materials (NORMs) in lake sediments may contribute to human
radiation exposure through multiple environmental pathways, making periodic radiological
assessment important for environmental protection. This study conducted a screening-level
radiological risk assessment of Jabi Lake, Abuja, Nigeria, using activity concentrations of
226Ra, 232Th, and 40K measured from a one-time sediment sampling campaign and the
RESRAD-Onsite computer code. Gamma spectrometric analysis showed that the measured
radionuclide concentrations and the corresponding radium equivalent activity were below the
recommended UNSCEAR limits, indicating that the present radiological status of the lake
sediments is unlikely to pose significant health concerns. Conservative RESRAD-Onsite
simulations identified fish consumption as the dominant potential exposure pathway and
indicated increased radiation dose and excess lifetime cancer risk under hypothetical long-term
exposure scenarios assuming persistent radionuclide concentrations. These results represent
conservative screening-level estimates rather than predictions of future environmental
conditions. The study provides baseline radiological data for Jabi Lake and demonstrates the
value of integrating environmental measurements with conservative modelling to support
preliminary risk evaluation and future environmental monitoring.
Open Access
Risk Assessment and Uncertainty Analysis of Radon-222 Concentrations in Groundwater Within Abuja, N...
Blessing C Nwankwo, and Yakubu V Ibrahim
abstract View article PDF
Radon-222 (222Rn) in groundwater is a potential source of internal radiation exposure through ingestion, particularly in regions where groundwater constitutes a major source of drinking water. This study presents an assessment of 222Rn concentrations, radiological risks, and measurement uncertainties in groundwater within Kubwa, Abuja, Nigeria, using liquid scintillation counting. Thirty groundwater samples collected during the peak dry season were analysed using a calibrated Tri-Carb 1000 TR liquid scintillation analyser, with corrections for radioactive decay and partitioning effects. The 222Rn concentrations ranged from below the detection limit to 2.30 Bq L?¹, with a mean of 0.29 ± 0.43 Bq L?¹. Estimated annual effective doses were of the order of 10?³ mSv y?¹, well below the recommended reference level of 0.1 mSv y?¹. Expanded relative uncertainties (k = 2) ranged from approximately 6% for higher-activity samples to over 20% for samples near the detection limit. The results indicate a very low radiological risk from 222Rn ingestion through groundwater and provide baseline data for the study area. The findings also demonstrate the importance of considering detection limits and measurement uncertainty in environmental radioactivity assessments.
Open Access
First-Principles Investigation of Alkaline-Earth Metal Co-Doped Hexagonal WO3 for Enhanced Near-Inf...
Umar Ibrahim, Alhassan Shuaibu, Adamu Muhammed, Yakubu T Aliyu, Musa Lawal, and Timothy Bulus
abstract View article PDF
The structural, thermodynamic, electronic, and optoelectronic properties of co-doped hexagonal tungsten trioxide (h-WO?) are investigated using Density Functional Theory (DFT) with the HSE06 hybrid functional and Density Functional Perturbation Theory (DFPT). To enhance near-infrared (NIR) response, beryllium is paired with alkaline-earth metals (Mg, Ca, Sr, and Ba) to form co-doped hexagonal tungsten bronze-like (h-HTB) configurations. Phonon-dispersion calculations confirm the dynamical stability of the co-doped systems, while formation-energy analysis indicates that the (Be, Ba) configuration is the most thermodynamically favorable, with a minimum formation energy of -2.68 eV. Electronic-structure calculations show that co-doping introduces impurity states within the pristine 3.3 eV band gap, leading to substantial band-gap narrowing across the dopant series. In particular, the (Be, Ba) system exhibits a reduced band gap of 0.9 eV, which is favorable for NIR absorption. Dielectric-function analysis further reveals a crossover in the real part of the dielectric function, ??(?), together with a resonant feature in the imaginary part, ??(?), near 0.9 eV, suggesting possible plasmonic behavior in the low-energy region. The calculated optical absorption spectra show strong NIR absorption with coefficients exceeding 10? cm?¹ and trends comparable to those of Cs?.??WO? benchmark systems, while retaining visible-light transparency. Overall, the results identify (Be, Ba) co-doped h-WO? as a thermodynamically favorable and optically promising candidate for smart-window and photothermal applications.
Open Access
Crystallographic and Spectroscopic Analysis of Activated Carbon Derived from MicrowaveAssisted KOH ...
Mary E Oni, John C Agomuo, Samuel M Udeh, and Salisu I Kunya
abstract View article PDF
KOH-activated carbon was prepared from banana peel waste by microwave heating (800 W) for 10, 20, 30, and 40 min with a constant KOH/precursor ratio of 1:1. The effect of irradiation time on crystal order and surface chemistry was systematically investigated by X-ray Diffraction (XRD) and Raman spectroscopy. XRD analysis showed that crystallinity and graphitization increased gradually with activation time; at 40 min, the crystallite size was 20.5 ± 0.6 nm and the microstrain was 0.00160. Raman spectroscopy showed a systematic evolution of the D/G band intensity ratio (ID/IG) from ~1.0 (carbonized) to a minimum of 0.75 at 30 min, indicative of optimised graphitic ordering. The 30-40 min samples showed the highest degree of graphitization, suggesting potential for enhanced electrical conductivity and charge-storage performance. These results demonstrate that microwave activation duration is a powerful parameter for tuning the structural properties of banana peel-derived activated carbon for energy and adsorption applications.
Open Access
Factors Influencing Households Intention to Adopt Solar Photovoltaic Technology for Net Metering in...
Lottie Singini, Chikumbusko Kaonga , and Christabel Kambala
abstract View article PDF
Adoption of solar photovoltaic (PV) technology is essential for the successful implementation of Malawi's newly introduced net-metering framework. However, evidence on urban household adoption intentions remains limited. This study investigated the sociodemographic and perceptual factors influencing households' intention to adopt solar PV for net-metering in
Mzuzu City, Malawi. A descriptive survey of 182 grid-connected households was conducted, and binary logistic regression, guided by the Theory of Planned Behaviour (TPB) and the Technology Acceptance Model (TAM), was used to identify significant predictors of adoption intention. The regression model was statistically significant (?² = 82.84, p < 0.001), explained
49% of the variation in adoption intention (Nagelkerke R² = 0.49), and correctly classified 80.2% of households. House ownership emerged as the strongest predictor of adoption intention, followed by economic perception, environmental perception, household size, electricity expenditure, gender, and education level, while age, marital status, income source,
and social and technical perceptions were not significant. The findings indicate that household adoption intention is driven primarily by structural characteristics and perceived economic and environmental benefits rather than demographic factors alone. The study further identifies landlord–tenant constraints and regulatory uncertainty as key barriers unique to the netmetering context, providing evidence to guide policies and targeted interventions that can accelerate household participation in Malawi's emerging net-metering programme.
Open Access
Design and Construction of an Ultrasonic Level Measurement Device Using Arduino Uno
Caleb Kambai, and Matthew N Agu
abstract View article PDF
Accurate and reliable level monitoring is essential in many industrial and scientific applications, including water storage, oil and gas processing, agricultural systems, and automated processes. Conventional contact-based measurement techniques are often limited by corrosion, contamination, and environmental effects, which can compromise measurement accuracy and system reliability. This study presents the design, construction, calibration, and performance evaluation of a non-contact ultrasonic level measurement device based on a custom ultrasonic sensing system integrated with an Arduino Uno microcontroller. The device operates on the ultrasonic time-of-flight principle, in which distance is determined from the travel time of reflected sound pulses. The developed prototype was tested over a measurement range of 2.9–400 cm using 51 measurement points, with five repeated readings recorded at each point to evaluate repeatability and measurement uncertainty. Statistical analysis yielded a mean absolute error (MAE) of 0.129 cm, a root mean square error (RMSE) of 0.163 cm, a standard deviation of 0.143 cm, and a coefficient of determination (R²) of 0.999998, demonstrating excellent linearity and measurement accuracy. The percentage error decreased with increasing measurement distance, reaching a minimum of 0.025% at 400 cm, which is attributed to reduced near-field instability and improved ultrasonic wave propagation at longer ranges. The results demonstrate that the developed system provides reliable real-time level measurement under controlled conditions and offers a cost-effective solution for industrial automation, reservoir monitoring, and storage tank applications.
Open Access
Energy Reliability and Its Implications for Translational Research Capacity in Nigeria’s Tertiary...
Ibrahim Taibat, Abdullahi S Adamu, Idris M Mustapha, Madaki S Kabiru, and Ibrahim A Muhammed
abstract View article PDF
This study investigated the implications of electricity reliability for translational research capacity in Nigerian tertiary institutions using a cross-sectional survey and quantitative laboratory energy assessment. Data were obtained from 90 respondents drawn from universities, polytechnics, and research institutes across Nigeria. Electricity reliability was estimated using an operational availability factor, while laboratory energy demand and backup energy adequacy were evaluated using standard engineering models. Findings revealed a highly unstable electricity supply, with 39% of respondents experiencing outages of 4–6 hours daily and 28% reporting interruptions exceeding 7 hours per day. Estimated electricity availability ranged from 0.75 to 0.83, while laboratory energy demand ranged from 10 to 50 kWh/day, depending on laboratory intensity and equipment usage. Although diesel generators (85%), solar photovoltaic systems (60%), and inverter systems (30%) were commonly used as backup energy sources, they were often inadequate for uninterrupted laboratory operations. Statistical analysis showed significant associations between electricity reliability and laboratory disruption (p = -0.68), project delays (p = -0.61), and research productivity (p = 0.64), all at p < 0.01. Linear regression further showed that electricity reliability was significantly associated with research productivity (B = 0.59, R^2 = 0.41, p < 0.01). Respondents also reported equipment downtime, disruption of sensitive laboratory procedures, loss of experimental samples, and delays in research timelines. The study concludes that electricity instability is an important infrastructural constraint on translational research capacity and recommends investment in hybrid renewable energy systems, dedicated research power infrastructure, and institutional energy planning to strengthen scientific productivity and innovation.
Open Access
Gum Arabic-Assisted TiO? Photoanode Fabrication for Dye-Sensitized Solar Cells Sensitized with Natu...
Isa M Mukhtar, Aliyu K Isiyaku, Nicodemus Kure, Auwal M Imam, Isah Mustapha, Tasiu Jamila, and Ibrahim Mustapha
abstract View article PDF
The stability and efficiency of dye-sensitized solar cells (DSSCs) are often limited by the degradation of key components, including dyes, electrolytes, and electrodes. This study investigates the effect of gum Arabic as a biopolymeric binder on TiO2 photoanode fabrication and the photovoltaic performance of DSSCs sensitized with a natural dye extracted from Sorghum bicolor grains. TiO2 films were prepared using the doctor-blade technique with gum Arabic concentrations of 0.56 g (Sample A) and 1.25 g (Sample B). Fourier transform infrared (FTIR) spectroscopy revealed O–H and C–O–C functional groups that promote dye adsorption and film stability, while UV–Visible spectroscopy confirmed strong absorption in the ultraviolet–visible region, extending the spectral response of TiO2. Photovoltaic performance was evaluated using current–voltage (I–V) measurements under dark and illuminated conditions. Sample B exhibited the best performance under illumination, with Voc = 0.60 V, Jsc = 1.50 mA/cm², Vmax = 0.46 V, Imax = 1.15 mA, Pmax = 5.3 × 10^-4 W, FF = 0.59, and n = 0.53%. The improved performance is attributed to enhanced visible-light absorption by anthocyanin dye molecules, reduced charge recombination, and improved electron transport. These findings demonstrate the potential of gum Arabic-modified TiO2 photoanodes and sorghum-derived natural dyes as low-cost and environmentally sustainable materials for DSSC applications.
Open Access
Morphological and Textural Characterization of Activated Carbon Derived from Microwave-Assisted KOH...
Mary E Oni, John C Agomuo, Samuel M Udeh, and Salisu I Kunya
abstract View article PDF
Banana peel biomass was converted into activated carbon through microwave-assisted KOH activation at a constant microwave power of 800 W and a KOH/precursor mass ratio of 1:1, using activation times of 10, 20, 30, and 40 min. The influence of activation time on the morphological and textural properties of the resulting activated carbons was systematically investigated using field emission scanning electron microscopy (FESEM) and nitrogen adsorption–desorption (BET) analyses. FESEM observations revealed progressive pore development and increased surface roughness with prolonged activation, reflecting the enhanced etching effect of KOH. Samples activated for 10–20 min retained fibrous plant-cell features and exhibited predominantly microporous structures, with a maximum BET surface area of 316 m² g^-1 at 20 min. Extending the activation time to 30–40 min further enhanced pore development, increasing the specific surface area to 471 m² g^-1 while reducing the average pore diameter from 2.86 to 1.90 nm. These changes indicate progressive pore refinement and the formation of a well-developed microporous network. The results demonstrate that microwave-assisted KOH activation provides a rapid and energy-efficient approach for producing porous activated carbon from banana peel biomass, with activation time serving as a key parameter for tailoring pore characteristics and surface area for potential environmental remediation and energy-storage applications.
Open Access
Evaluation of Radiological Health Hazard Indices of Natural Radioactivity in Vegetables from Irriga...
Abubakar Yahaya, John C Agomou, Rabi’u A Tafida, Yakubu V Ibrahim, Hayatu Umar, and Suleiman Yunusa
abstract View article PDF
Natural radionuclides in agricultural products may contribute to long-term radiological health risks through dietary intake. This study assessed the activity concentrations of U-238, Th-232, and K-40 in vegetables cultivated in irrigation farms within Soba Local Government Area, Kaduna State, Nigeria, and evaluated the associated radiological health risks. Pepper, onion, and tomato samples collected from nine locations were analyzed using NaI(Tl) gamma-ray spectrometry. Radiological parameters, including committed effective dose (CED), lifetime cancer risk (LCR), and internal hazard index (H?), were estimated for adults and children using standard ICRP dose conversion coefficients. The highest radionuclide concentrations were recorded in Kinkiba, with values of 2.45, 7.93, and 556.84 Bq kg?¹ for U-238, Th-232, and K-40, respectively. Total CED values ranged from 4.86 × 10?? to 2.85 × 10?? mSv yr-1 for adults and 1.97 × 10?? to 1.37 × 10?? mSv yr-1 for children. The maximum LCR obtained was 1.42 × 10?², while all H? values remained below the recommended safety threshold. Although spatial variations in radionuclide concentrations were observed, the evaluated radiological indices indicate low ingestion-related health risk under current exposure conditions. The study provides baseline radiological data for environmental monitoring and food safety assessment in agricultural communities.
Open Access
Measurement of Indoor Radon Concentration and Associated Health Risks in Selected Elementary School...
Oyelade A Emmanuel, and Obed I Rachel
abstract View article PDF
Indoor radon concentration was measured in selected elementary schools across Lafia, Nasarawa State, Nigeria, using passive diffusion cups fitted with CR-39 detectors. The rooms were selected based on varying natural ventilation conditions and height above ground level. Detectors were deployed in classrooms and offices for a period of 90 days. After exposure, the detectors were etched using sodium hydroxide (NaOH) at 90 °C for 3 hours. Alpha tracks were counted and photographed using a digital camera attached to a microscope and computer system. The arithmetic and geometric mean radon concentrations were 193.3 Bq m?³ and 182.4 Bq m?³, respectively. The mean annual effective lung dose was 0.24 mSv·y?¹, with an excess lifetime cancer risk of 1.0 MPY?¹. Factors such as ventilation rate, proximity to the ground, and construction materials of floors, walls, and ceilings were investigated. An inverse relationship (R² = 0.6) was observed between radon concentration and ventilation rate. Rooms situated closer to the ground exhibited higher radon levels. Concrete and asbestos materials were associated with higher radon concentrations, whereas painted and carpeted surfaces recorded lower values. The measured radon concentrations were below the International Commission on Radiological Protection recommended action level of 300 Bq m?³ for workplaces.
Open Access
Assessment of Natural Radioactivity and Associated Radiological Risks in Cements Produced and Used ...
Aeron M A Nahuku, Alinue Musopole, Samson Nyirenda, Fabiano G D Thulu, Estiner W Katengeza, Bernard Thole, and Chikumbusko C Kaonga
abstract View article PDF
This study assessed the natural radioactivity and associated radiological health risks of commercially available cement brands produced and distributed in Malawi to evaluate compliance with international radiation safety standards for building materials. Cement samples were analyzed for 226Ra, 232Th, and 40K activity concentrations using high-purity germanium (HPGe) gamma-ray spectrometry. The mean activity concentrations of 226Ra, 232Th, and 40K were 29.9 ± 4.6, 17.3 ± 2.8, and 309.7 ± 34.8 Bq kg?1, respectively, all below the UNSCEAR recommended limits. The mean radium equivalent activity (Raeq) was 78.4 ± 8.5 Bq kg?1, significantly lower than the recommended limit of 370 Bq kg?1. Calculated radiological hazard indices, including external hazard index, internal hazard index, gamma index, and alpha index, were all below the recommended safety threshold of unity. The mean outdoor and indoor absorbed dose rates were 36.2 ± 8.5 and 72.5 ± 7.5 nGy h?1, respectively, while the corresponding annual effective doses were 0.044 ± 0.0046 and 0.178 ± 0.019 mSv y?1. The evaluated excess life cancer risk values were well below internationally accepted reference limits. These results demonstrate that the investigated cement products do not pose significant radiological hazards to the public and are safe for use as construction material. However, periodic assessment and monitoring of these natural radionuclides in cements and other building materials in Malawi are highly recommended.
Open Access
Exploring Intermediate and Natural Inflation under a Nonminimal Derivative Coupling: The John-Georg...
Ferdinand Mavoa, Mohamed C Sow, Hoavo Hova, Moussiliou G Ganiou, Cheikh S Touré, and Antonin D Kanfon
abstract View article PDF
Intermediate and natural inflation are investigated within a nonminimal derivative coupling
scalar field model, namely the John–George framework. The derivative coupling introduces
enhanced gravitational friction, modifying inflaton dynamics and enabling sustained
accelerated expansion even for sub-Planckian parameter values. The field equations and slowroll parameters are derived in a flat Friedmann–Lemaître–Robertson–Walker spacetime. For
intermediate inflation, the effective potential is reconstructed assuming a power-law scalar field
evolution, while a periodic potential with a decay constant, f describes the natural inflation.
Numerical analysis of inflationary observables yields ns = 0.96397 and r = 0.0019 for
intermediate inflation, and ns = 0.961176 and r = 0.00651 for natural inflation at N = 60efolds. These predictions are in excellent agreement with Planck and BICEP/Keck constraints.
The enhanced friction mechanism slows the inflaton evolution and suppresses the tensor-to-scalar ratio, bringing the model well within observational bounds. Parameter analysis indicates
that m ~ 0.5–1 and f ~ 0.5 provide optimal agreement with data. The John–George
framework, therefore, constitutes a viable and competitive alternative to standard inflationary
scenarios.
Open Access
Performance Evaluation of a Thermo-luminescent Dosimetry System for Occupational Monitoring in Fede...
Bashir G Muhammad, Maryam L Maikudi, Suleiman Bello, Ahmed R Usman, and Usman Sani
abstract View article PDF
Thermo-luminescent dosimeters (TLDs) are widely used for occupational radiation monitoring
due to their sensitivity, reusability, and tissue equivalence. This study evaluates the performance of a TLD system deployed at the Federal Teaching Hospital, Katsina, Nigeria. Key performance parameters assessed include batch homogeneity, reproducibility, and dose linearity in accordance with IEC 1066 standards. The homogeneity test yielded a percentage
variation of 13.3%, well within the acceptable limit of 30%. Reproducibility analysis yielded a coefficient of variation of 7.71%, which is slightly above the IEC threshold of 7.5%. The dose
linearity is in good agreement with irradiated dose values, with deviations ranging from 1.3% to 8.0% and a regression coefficient (R²) of 0.9985, indicating excellent linearity. Overall, the system exhibits reliable performance for occupational monitoring, with minor deviations attributable to environmental and operational factors. Continuous quality assurance is recommended to ensure sustained compliance with international standards.
Open Access
Comparative Analysis of Classical Machine Learning and Deep Learning Architectures for Handwritten ...
Tamakloe A Vivian, Maikusa S Abdulrahman, and Eli A Jiya
abstract View article PDF
Handwritten digit recognition remains a core problem in computer vision, with both classical machine learning (ML) and deep learning (DL) models widely applied but rarely compared under identical conditions. This study presents a controlled evaluation of Logistic Regression, Support Vector Machine (SVM), Convolutional Neural Network (CNN), Long Short-Term
Memory (LSTM), and a hybrid CNN–LSTM using the MNIST dataset. Data were normalized, reshaped, and encoded within a reproducible Python pipeline executed in a CPU-only environment. Classical models used flattened inputs, while DL models leveraged spatial
structure. Results show a clear progression in performance: Logistic Regression (92.00%),
SVM (97.59%), LSTM (98.53%), and CNN/CNN–LSTM (98.96%). CNN achieved the best overall metrics (precision 0.9897, recall 0.9896, F1-score 0.9896, AUC 0.999926) with
225,034 parameters, a training time of 209.77 seconds, and an inference time of 2.32
milliseconds. Statistical analysis confirmed CNN’s superiority. The findings demonstrate that
architectures aligned with data structure, particularly CNNs exploiting spatial locality, deliver
optimal performance. While classical models remain competitive, their reliance on flattened
representations limits effectiveness. The near-ceiling MNIST results further suggest the need
for more challenging benchmarks to distinguish advanced models.
Open Access
Effect of Deposition Time on the Optoelectronic Properties of CdS Thin Films Synthesized via Chemic...
Simon Ja’afaru, Isaac H Daniel, Yakubu A Tanko, Nicodemus Kure and Olayinka A Babalola
abstract View article PDF
Cadmium sulphide (CdS) thin films were synthesized via chemical bath deposition (CBD) to investigate the influence of deposition time on their optoelectronic properties. The films were deposited at 80 °C for durations ranging from 5 to 30 minutes. Film thickness increased from 1.5 to 3.0 µm with increasing deposition time, while surface roughness exhibited a non-linear variation associated with nucleation, growth, and grain agglomeration processes. X-ray diffraction of the 30-minute film confirmed a polycrystalline hexagonal CdS structure. Optical analysis revealed a non-linear variation in the bandgap, decreasing from 2.42 eV to 2.07 eV, with strong absorption in the visible region and a maximum absorption at 25 minutes. The refractive index, dielectric constants, and optical conductivity also varied with deposition time, indicating changes in optical response and carrier transport. Hall effect measurements confirmed n-type conductivity, with mobility increasing up to 25 minutes before decreasing, while carrier concentration and resistivity exhibited deposition-time dependence. The 20-minute film had a good mix of optical, electrical, and surface properties. The 30-minute film, on the other hand, had the highest photosensitivity (3110.08%) and responsivity (1.76 × 10?² mA.W?¹). These findings indicate that deposition time is an essential factor for optimizing the optoelectronic performance of CdS thin films for photodetector applications.
Open Access
Ab initio study of structural, electronic, and magnetic properties of pristine and Fe-doped Al2Si2O...
Yakubu A Tanko
abstract View article PDF
First-principles calculations based on density functional theory (DFT) were employed to investigate the structural, electronic, and magnetic properties of pristine and single Fe-doped Al2Si2O5(OH)4 (kaolinite). All calculations were performed within the GGA–PBE framework using a plane-wave pseudopotential approach. Convergence tests with respect to kinetic energy
cut-off and k-point sampling confirmed that 40 Ry and a 5×5×5 Monkhorst–Pack grid ensure total energy convergence within 1 meV/atom for both systems. Structural optimization of
pristine kaolinite reproduces the characteristic layered framework of SiO4 tetrahedra and AlO6 octahedra. Upon Fe substitution at an octahedral Al site, localized structural relaxation is observed, with elongated Fe–O bonds (?1.95–2.12 Å), minor lattice expansion (<2%), and
measurable octahedral distortion indices (~2–3%). The calculated binding energy (~0.68 eV) indicates that Fe incorporation is thermodynamically feasible under suitable conditions.
Electronic structure analysis reveals that pristine Al2Si2O5(OH)4 is an indirect wide-band-gap insulator with a calculated GGA gap of 4.19 eV. Fe substitution induces spin polarization, reduces the band gap to 3.23 eV, and introduces Fe-3d states near the band edges. Spin splitting
between majority and minority channels confirms magnetic ordering, yielding a local magnetic
moment of ~3.8 ?B per Fe atom, consistent with high-spin Fe³? in octahedral coordination.
Charge density and spin density analyses reveal pronounced Fe–O hybridization and localized
magnetic moment formation. These findings demonstrate that Fe doping effectively tunes the
structural stability, electronic band gap, and magnetic behavior of kaolinite, highlighting its
potential for functional and catalytic applications.
Open Access
Comparative Electrothermal Characterization of Organic Light-Emitting Diodes Using Thermocouple and...
Abdurrasheed B Magaji, and Aliyu A Masanawa
abstract View article PDF
This paper reports a comparative experimental study on the thermal behavior of organic lightemitting diodes (OLEDs) under varying electrical driving conditions. Temperature
distributions were simultaneously measured at both the top emission surface and rear substrate
surface using K-type digital thermocouples and high-resolution infrared thermography over
continuous 120 minutes operational periods. The OLED device was characterized at multiple
direct current levels (45 mA, 30 mA, 20 mA, and 5/15 mA) to establish comprehensive thermal
profiles. Experimental results reveal that device surface temperature, used as a proxy for
junction temperature, exhibits strong positive correlation with applied current density, with
thermal steady-state conditions achieved between 60–110 minutes depending on operating
conditions. The rear surface consistently exhibited temperatures 3–6 °C higher than the top
surface across all current levels, indicating heat accumulation within the substrate and the
thermal resistance of the multilayer OLED structure. Thermal imaging revealed temperature
gradients of approximately 1.5–2.5 °C between device center and edges at steady state.
Comparison of measurement methodologies shows infrared thermography consistently
recorded temperatures 1–3°C higher than thermocouple measurements due to emissivity
considerations and surface radiation effects. These findings quantify the thermal management
requirements for OLED devices and establish baseline thermal characteristics essential for
reliability modeling, lifetime prediction, and packaging optimization in display and lighting
applications. The proposed dual-measurement framework establishes a practical experimental
benchmark for validating electrothermal simulations of OLED devices. Accurate experimental
thermal characterization remains a prerequisite for predictive electrothermal modelling of
emerging OLED technologies.
Open Access
Bandwidth Enhancement in White LED Visible Light Communication Systems Using Blue Optical Filtering...
Abdurrasheed B Magaji, and Shariff M Abdulkadir
abstract View article PDF
Visible Light Communication (VLC) enables short-range high-speed data transmission using
white light-emitting diodes (LEDs) for both illumination and communication. However,
phosphor-converted white LEDs suffer from limited modulation bandwidth due to slow
phosphor relaxation dynamics, resulting in signal attenuation, inter-symbol interference (ISI),
and degradation of signal-to-noise ratio (SNR) at higher frequencies. In this work, performance
enhancement using blue optical filtering combined with electrical equalization was
experimentally investigated for phosphor-converted white LEDs transmitting On-Off Keying
Non-Return-to-Zero (OOK-NRZ) signals. Measurements were conducted over a 40 cm indoor
line-of-sight link with data rates varied from 0.5 to 20 Mbps. Two equalizer configurations
were evaluated: a single-stage RC network (EQ1) and a three-stage cascaded RC network
(EQ2). Frequency sweep measurements (representing OOK symbol rate variation) were
performed to evaluate received signal strength, SNR, Bit Error Rate (BER), cumulative signal
improvement, and normalized performance metrics. Results show that EQ2 provides
significantly superior performance compared to EQ1, achieving a peak SNR of 34 dB at 10
Mbps with a corresponding BER reduction to 10??, representing approximately 8 dB SNR
improvement over EQ1 at the optimal frequency. The optimal enhancement region for EQ2 lies
between 0.5 and 12 MHz, where LED channel attenuation is most dominant. Polynomial fitting
was used as an empirical approximation, with fifth-order models providing the highest
regression accuracy for EQ2 (R² = 0.90). The results demonstrate that the combination of blue
optical filtering and multi-stage equalization effectively mitigates LED bandwidth limitations,
significantly improving VLC performance for indoor smart lighting and short-range wireless
applications.
Open Access
Long-Term Characterization of Vertical Radio Refractivity Gradients and Tropospheric Propagation Co...
Usman S Lami, Ikechiamaka N Florence, Akinbolati Akinsanmi, Isaac H Daniel, Owolabi J Adeyemi, Abubakar Dalhat, Stephen C Nnochin, Akusu O Christiana, Mansur Bala, Bolorunduro C Blessing, Mohammed Mohammed, and Adamu Idris
abstract View article PDF
This study presents a comprehensive long-term evaluation of vertical radio refractivity and
refractivity gradients over selected locations in North-Central Nigeria. Forty-one years (1980–
2020) of meteorological data obtained from the ERA5 reanalysis dataset of the European
Centre for Medium-Range Weather Forecasts (ECMWF) were analyzed. Air temperature,
atmospheric pressure, and relative humidity at heights of 12 m, 100 m, and 250 m above ground
level (AGL) were used to compute radio refractivity using ITU-R formulations. Vertical
refractivity gradients were subsequently derived and interpreted within established propagation
regime classifications. Results reveal a consistent decrease in refractivity with increasing
altitude across all locations. Wet-season refractivity values exceed dry-season values due to
enhanced moisture contribution to the wet refractivity component. Mean vertical refractivity
gradients were -125.65 N/km in Minna, -87.36 N/km in Lokoja, and -77.54 N/km in Jos.
These values exceed the standard atmospheric gradient (? -39 N/km) in magnitude, indicating
persistent super-refraction conditions, particularly in lowland and humid environments. The
findings demonstrate that regional topography and atmospheric moisture distribution
significantly influence radio wave bending characteristics. Incorporating location-specific
vertical refractivity gradients into terrestrial propagation models is essential for improving
reliability and interference prediction in subtropical continental climates.
Open Access
High-Efficiency Cs2TiBr6 Lead-Free Perovskite Solar Cell Enabled by All-inorganic CZTS/NiO Double H...
Peverga R Jubu, Michael O Awoji, Bunmi J Akeredolu, Adebayo T Adepoju, Sekav J Ikwe, Denen S Igba, Francis Aungwa, Terdoo M Ikpa, Iheke M Nwachukwu, and Emeka E Oguzie
abstract View article PDF
Ti-based Cs?TiBr? double-halide perovskites are promising for optoelectronic and renewable
energy applications, offering a non-toxic alternative to Pb-based perovskite solar cells (PSCs).
This study uses SCAPS-1D to simulate a Cs?TiBr?-based PSC incorporating a CZTS/NiO
double hole transport layer (HTL) to enhance power conversion efficiency (PCE). The double
HTL improves hole transport, strengthens electron blocking, and reduces interfacial
recombination. The optimized FTO/CeOx/Cs?TiBr?/CZTS/NiO/Au architecture achieves a
PCE of 27.78%, significantly higher than the prototype (11.62%), under optimized parameters
including absorber and interface defect densities, electron capture cross-section, and CZTS
thickness. Notably, the ETL-free structure (FTO/Cs?TiBr?/CZTS/NiO/Au) attains the same
PCE (27.78%), indicating that the CeOx ETL is dispensable for a simplified, and cost-effective
design. The achieved efficiency exceeds previous reports on Cs?TiBr?-based PSCs
Open Access
Dopant-Induced Modulation of Structural and Magnetic Properties in Strontium Ferrite Perovskite Nan...
Dipak Nath, and Robert A Xavier
abstract View article PDF
This research centres on enhancing the magnetic properties of Europium (Eu) doped Strontium
Ferrite (SrFeO3) nanomaterials, synthesized successfully using the solution combustion
method. The study explores doping concentrations of x = 0.0, 0.5, and 1.0 and their effects on
the structural, morphological, and magnetic characteristics. Techniques such as X-ray
diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), and a
Superconducting Quantum Interference Device (SQUID) magnetometer were employed. XRD
analysis shows a reduction in particle size as the Eu dopant concentration increases, while
FESEM images reveal uniformly formed nanoparticles with notable agglomeration. Magnetic
properties were investigated through temperature and field-dependent magnetization
measurements. The field dependence of magnetization at both 5 K and 300 K indicates
ferromagnetic behaviour across all samples, with the higher Eu doping concentrations resulting
in enhanced magnetic moments. These findings suggest that Eu-doped SrFeO3 nanomaterials
hold great promise for applications in spintronics, sensors, and microwave-absorbing devices.
Open Access
Emerging Renewable Polymer Platforms for Biomedical Interfaces, Bioadhesives, and 3D Printing...
Agbogo U Victor, Okafor O Evelyn, Mamman P Godiya, Igogo A Roseline, Ike-Muonso N Martin, and Kollere A Shehu
abstract View article PDF
The traditional polymer industry, which depends heavily on fossil resources, faces increasing
challenges due to resource depletion, environmental damage, and sustainability issues linked
to petroleum-based materials. In response, the development, synthesis, and regeneration of ecofriendly, renewable bio-based polymers have gained significant attention from both science and
industry as promising alternatives. In addition to reducing the negative environmental impact
of conventional plastics, biodegradable and renewable polymers now play a crucial role in
enabling advanced biomedical functions, particularly at biological interfaces. Recent advances
have highlighted bioadhesive systems as a crucial subset of renewable polymers, enabling
effective interactions between materials and biological tissues under physiologically relevant
conditions. These bioadhesive materials, made from natural synthetic bio-based, or hybrid
polymer platforms, are increasingly used in biomedical applications such as wound closure,
tissue sealing, implant fixation, drug delivery, and biofabrication. At the same time, integrating
biodegradable polymers and bioadhesive formulations into three-dimensional (3D) printing
technologies improves process efficiency, material accuracy, and design flexibility while
reducing waste and environmental impact. This review critically examines emerging renewable
polymer platforms, with a focus on bioadhesive systems, biodegradable polymers, and additive
manufacturing techniques. The discussion includes the benefits, limitations, recent advances,
and future outlook of these materials within the context of sustainable biomedical interfaces
and 3D-printed structures. By offering an integrated view, this work underscores the
transformative potential of renewable polymer-based bioadhesives and 3D printing in
advancing next-generation biomedical engineering while promoting circular and sustainable
material practices. This manuscript provides a comprehensive narrative review of emerging
renewable polymers for biomedical interfaces, bioadhesives, and 3D printing.
Open Access
Geothermal Resources Exploration in Kerang Highland, Jos Plateau, Nigeria Using Aeromagnetic and Ae...
Abubakar I Abubakar, Cyril G Afuwai, Abdullahi N Khalid, Auwal Nuhu, Raudha A Girka, Mshelia Abdulrazaq, and Simon Magaji
abstract View article PDF
This study investigates the geothermal energy potential of the Kerang Highland, Jos Plateau,
Nigeria, using high-resolution aeromagnetic and aero-radiometric datasets: Sheet 168
(Naraguta), 169 (Majuju), 189 (Laura), and 190 (Pankshin), obtained from the Nigerian
Geological Survey Agency (NGSA). The research applies spectral analysis of aeromagnetic
data to estimate Curie Point Depths (CPD), geothermal gradients, and subsurface heat flow,
while aero-radiometric data are analyzed to determine radiogenic heat production based on
uranium (U), thorium (Th), and potassium (K) concentrations. The Curie Point Depths in the
study area vary from 6.83 km to 14.39 km, corresponding to geothermal gradient values ranging
from 40.3 °C/km to 84.9 °C/km, and heat flow values from 100.8 to 212.3 mW/m², and
Radiogenic heat generation ranging between 2.6 and 3.8 µW/m³. The results reveal shallow
CPDs, high heat flow, high geothermal gradient, and high radiogenic heat in Blocks (4, 9, 13,
14, 20, 21, 24, and 25 ), indicating geothermally active zones. The dominant NE–SW structural
trend, derived from magnetic lineament analysis, correlates with the regional tectonic fabric of
the Younger Granite Complex. The integration of aeromagnetic and radiometric datasets
demonstrates a strong correlation between high radiogenic heat zones and high heat flow. This
suggests that both crustal radioactive decay and mantle upwelling contribute to the anomalous
geothermal regime. The study concludes that Kerang Highland possesses high geothermal
energy potential suitable for direct-use applications and binary-cycle power generation. Further
geophysical, geochemical, and drilling investigations are recommended to validate and
quantify the resource.
Open Access
This article is temporarily suspended pending administrative compliance: A Hodge Theory-Driven Quan...
Yang Ou and Wenming Sun
abstract View article PDF
Article Status: Temporarily Suspended
This article has been temporarily suspended by the publisher due to pending administrative requirements related to the publication process.
The suspension is not related to the scientific content, validity, or integrity of the work.
The article will be reinstated once the outstanding administrative issues are resolved.
For further information, please contact the editorial office at:
editor-in-chief@physicsaccess.com
support@physicsaccess.com
physics_access@kasu.edu.ng
Open Access
Design, Performance, and Cost Optimization of a 10.2 kWp Grid-Tied Hybrid Photovoltaic System in Ow...
Michael I Ejike
abstract View article PDF
This study presents the design and techno-economic optimization of a 10.2 kWp grid-tied
hybrid photovoltaic (PV) system for residential applications in Owerri, Nigeria. The objective
is to develop a reliable and cost-effective solar power solution capable of mitigating
dependence on the unstable national grid. Household energy demand was estimated based on
the daily consumption patterns of common appliances and their average operating hours. Using
analytical design methods, appropriate PV, inverter, and battery capacities were selected and
optimized to enhance overall system efficiency. The final configuration comprises twenty 510
W monocrystalline PV modules (10.2 kWp total capacity) coupled with a 10 kW hybrid
inverter, yielding a DC/AC ratio of approximately 1.02. Under typical meteorological
conditions in Owerri, the optimized array is projected to generate about 36.72 kWh per day.
Economic analysis, based on a capital cost of N6.6 million, annual maintenance of N66,000, a
20-year lifetime, and a 7% discount rate, indicates a levelized cost of electricity (LCOE) of
approximately N30.5 /kWh and a simple payback period of 7.5 years. The results demonstrate
that with realistic load estimation and properly matched components, small-scale PV systems
can offer a technically feasible and economically sustainable alternative to grid electricity in
Nigeria’s residential sector.
Open Access
Heavy Metal and Carcinogenic Risk Assessment of a Gold Mine Turned Residential Area in Mokuro Area ...
Grace O Akinlade, Danjuma D Maza, Oluwakemi O Olawolu, Delight O Babalola, John A O Oyekunle, and Jo
abstract View article PDF
Artisanal gold mining along the Ife-Ijesa axis in Osun State, Nigeria, is widespread, and many abandoned mining sites are now being repurposed into residential areas without a prior assessment of the risks associated with heavy metals. This study examines the carcinogenic and non-carcinogenic health risks associated with heavy metal contamination in soil, water, and plant samples from a reclaimed gold mine in Mokuro, Ile-Ife. Twelve (12) samples consisting of soil, water, and plants were collected across the reclaimed mining site using standard sampling methods. Concentrations of arsenic (As), lead (Pb), cadmium (Cd), and zinc (Zn) were determined by atomic absorption spectroscopy (AAS). Results indicated that mean soil concentrations of As, Pb, Cd, and Zn were 0.70±0.278, 1.03±0.104, 2.07±0.236, and 2.47±0.202 mg kg-1, respectively, within regulatory limits. However, drinking water contained 0.012±0.006, 0.007±0.004, 0.019±0.006, and 0.023±0.007 mgL-1 as mean ± standard deviation, respectively, of As, Pb, and Cd, with cadmium levels exceeding the WHO limit of 0.003 mg L-1. In plant samples, cadmium in bitter and guava leaves (0.34 and 0.49 mg kg-1, respectively) surpassed FAO/WHO limits (0.2 mg kg-1), suggesting potential dietary exposure risks. Risk assessments revealed that the non-carcinogenic hazard risk index (HRI) varied from 0.174 in cassava leaf to 4.342 in cassava tuber. The total carcinogenic risk (TCR) also varied from 6.86 x 10-5 in cassava leaf to 1.10 x 10-3 in cassava tuber, thus presenting cassava tubers grown on the site as a major source of exposure to both non-carcinogenic and carcinogenic risks since its HRI >1 and TCR > 10-4 due to arsenic contamination. Although most contamination levels are within limits, the high cadmium in water and arsenic in cassava warrant precautionary measures such as water treatment and dietary monitoring.
Open Access
Cluster Analysis on Radioactivity Levels of K-40, Ra-226, and Th-232 at Chikun Environment of Kadun...
Handan T Elisha, Sarki S Habila, Shirley O Yakubu, Umar Isah, and Davou H Daze
abstract View article PDF
Exposure to ionizing radiation from both natural and anthropogenic sources poses serious environmental and health concerns. This study used hierarchical clustering to investigate the spatial distribution of naturally occurring radionuclides K-40, Ra-226, and Th-232 in soil samples collected from 14 locations within Chikun Local Government Area (LGA), Kaduna State, Nigeria. Using the R statistical package, single and complete linkage methods were implemented on Euclidean distance matrices to identify natural groupings among the sampling sites. The optimal number of clusters, determined through the elbow and silhouette methods, was found to be two (2), with further sub-groupings evident in the complete linkage dendrogram. The first cluster comprises the KRPC1 and KRPC2 sampling sites, situated near the Kaduna Refining and Petrochemical Company. These sites exhibited the highest mean activity concentrations of the measured radionuclides, with values of 106.14 Bq/kg for K-40, 265.84 Bq/kg for Ra-226, and 827.52 Bq/kg for Th-232, respectively. The second cluster comprised residential neighborhoods and nearby waste disposal sites, demonstrating comparatively lower activity concentrations of the radionuclides. This spatial distribution suggests that refinery operations exert a pronounced influence on localized radioactivity levels, while the surrounding residential and dumpsite areas exhibit only residual contamination. These results underscore the effectiveness of cluster analysis as a tool for interpreting environmental radioactivity patterns and reinforce the need for sustained monitoring and public health safeguards in industrialized settings.
Open Access
Relativistic Study of Motion of Photons in an Elliptical Gravitational Field
Timothy Bulus, Abdullahi Danlami, and Abubakar Yushau
abstract View article PDF
Fields of elliptical objects can be considered elliptically symmetric, such that the structure, matter, and field of such an object can be defined in terms of an elliptically symmetric space metric. In this study, the need to employ a line element in the gravitational field due to a static and ellipsoidal isolated gravitating mass point was adopted. The relativistic equation of motion of an ellipsoidal star is obtained by applying conditions, such as the covariant and contravariant components of the metric tensor on the metric of the equation, where the metric tensor, affine connections, and geodesic equations were put to work. The contra-variant metric tensor of the basic metric tensor in its covariant form was obtained using the quotient relation. These results offer refined insight into the interpretation of astrophysical observations near non-spherical massive bodies such as oblate stars, elliptical galaxies, or deformed compact objects. The findings contribute to the broader effort of modeling light propagation in realistic, anisotropic gravitational environments within the framework of general relativity.
Open Access
The Impact of Temperature on the Performance of White LEDs for Visible Light Communication
Abdurrasheed B Magaji, Florence N Ikechiamaka, and Akinbolati Akinsanmi
abstract View article PDF
Visible Light Communication (VLC) is a promising wireless communication technology that
utilizes Light Emitting Diodes (LEDs) for high-speed data transmission. However, its
performance is significantly affected by temperature variations, which impact the quality factor
(Q-factor), signal integrity, and modulation bandwidth. Additionally, frequency-dependent
distortions and external noise sources further degrade transmission quality, increasing Bit Error
Rate (BER). This study investigates the effect of temperature on the Q-factor at different driver
currents (100, 200 and 300 mA) and explores post-equalization techniques to enhance LED
modulation bandwidth. An R//C equalization circuit was implemented to compensate for
frequency-dependent losses, while a blue optical filter minimized interference and improved
the Signal-to-Noise Ratio (SNR). Experimental results indicate that at a driver current of 200
mA and a temperature of 34.8 °C, the highest Q-factor of 14.250 was achieved. Furthermore,
an adaptive equalization scheme enabled a 20 Mbps data rate over a 10 cm transmission
distance, demonstrating its effectiveness in mitigating signal degradation. The findings
highlight the importance of post-equalization in overcoming temperature-induced performance
degradation in VLC systems. The proposed approach enhances system stability and reliability,
making VLC a viable option for high-speed optical wireless communication under varying
thermal conditions.
Open Access
High Order Harmonic Generation using Inhomogeneous Two Colour Field, Polarization Gating and Static...
Onsure D Nyang’au, Kebwaro J Monari, Rurimo G Kihara and Njoroge S Maina
abstract View article PDF
In this study, high-order harmonic generation was investigated under the combined influence
of three enhancement schemes: a plasmonic-enhanced two colour field, modulated polarization
gating, and a static electric field. Numerical simulations based on the one-dimensional timedependent Schrödinger equation (1D-TDSE) were carried out to analyze the influence of field
inhomogeneity, polarization modulation, and electron trajectory control on harmonic spectra.
The analysis demonstrates that an increase in the inhomogeneity parameter, together with
precise tuning of the polarization angle, produces extended harmonic cut-offs and more intense
bursts near peak field cycles. The introduction of a static electric field further improved the
harmonic conversion efficiency, while the combined application of all three mechanisms yields
harmonic spectra characterized by two distinct plateaus, broadened spectral bandwidths, and
significantly higher emission yields. A high harmonic cut-off reaching the 600th order is
observed in the first plateau, while the second plateau extends beyond the 1550th order. Timefrequency spectrograms reveal well-defined harmonic bursts and high-energy electron
recollisions contributing to this extension. These findings confirm that the synergy of
polarization gating, plasmonic field enhancement and static field confinement offers a robust
pathway for generating bright and broadband extreme ultraviolet (XUV) continua, which are
essential for advancing attosecond pulse generation and ultrafast spectroscopy
Open Access
Evaluation of Excess Lifetime Cancer Risk for Environmental Exposures in Kaduna, Nigeria
Gyuk P Musa, Bello I Ayodeji, Nicodemus Kure and Isaac H Daniel
abstract View article PDF
This study assessed the excess lifetime cancer risk (ELCR) associated with natural radioactivity in marble samples from Gidan Waya and Ungwar Damishi, North Central Nigeria. Activity concentrations of 226Ra, 232Th, and 40K were determined using gamma ray spectrometer with a NaI (Tl) detector. From these data, radiological hazard indices, including ELCR, were
calculated. Marble samples from Gidan Waya exhibited ELCR values ranging from 0.104 × 10-³ to 0.250 × 10-³, with an average of 0.150 × 10-³, which is below the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) reference value of 0.29 × 10-³. These results indicate that long-term use of Gidan Waya marble poses a low cancer risk
to the population. In contrast, marble from Ungwar Damishi showed significantly higher ELCR
values, ranging from 1.82 × 10-³ to 2.92 × 10-³, with an average of 2.17 × 10-³. Though other hazard indices, such as the radium equivalent activity (Raeq), absorbed dose rate, and annual
effective dose, were within recommended safety thresholds, the elevated ELCR values suggest
a potential health concern for long-term indoor exposure. The findings imply that marble from
Gidan Waya is radiologically safe for construction and decorative purposes, while marble from
Ungwar Damishi requires further investigation. In particular, long-term indoor exposure scenarios, radon exhalation rates, and refined dose modelling should be considered in future studies to provide a more comprehensive risk profile. This study not only advances understanding of natural radioactivity in building materials in Nigeria but also contributes to the achievement of Sustainable Development Goal 3 (SDG 3: Good Health and Well-being) by informing safe material use and promoting public health protection.
Open Access
Synthesis and Characterization of Syzygium Cumini Leaves Mediated Nickel Oxide Nanoparticles...
Bawa Emmanuel, Mashingil P Moses, Dhlamini Mokhotjwa, Mohammed B Hudu, Solomon A Mamuru, Samuel Egga
abstract View article PDF
Nickel oxide (NiO) nanoparticles possess unique properties that make them highly valuable for applications in energy storage, catalysis, sensors, and biomedicine. Conventional synthesis routes often involve toxic chemicals and high energy requirements, posing environmental concerns. In this study, NiO nanoparticles were successfully synthesized via a green synthesis route using Syzygium cumini leaf extract as both a natural reducing agent and capping agent. The optical properties were monitored through UV-Vis spectroscopy, revealing the transformation from nickel chloride to NiO nanoparticles with a distinct absorption shift from ~394 nm to ~286 nm, confirming nanoparticle formation and semiconducting behavior. Phytochemicals screening results and Fourier Transform Infrared (FTIR) analysis identified functional groups in the extract, including phenols, flavonoids, and carboxylic groups, suggesting their role in reduction and stabilization. Scanning Electron Microscopy (SEM) images showed aggregated nanoparticles with irregular crystalline morphology, while X-ray diffraction (XRD) confirmed a face-centered cubic phase with an average crystallite size of 15.5 nm. The study demonstrates the effectiveness of S. cumini extract in producing NiO nanoparticles sustainably and highlights the potential of plant-mediated routes for environmentally friendly nanomaterial synthesis.
Open Access
Plasmonic Enhancement and Lifetime Extension of Perovskite Solar Cells via Biosynthesized Silver Na...
Jamila Tasi’u, Muhammad Y Onimisi, Eli Danladi, Kurawa S Mustafa, Haruna Ali, Kehinde Ogunmoye, John
abstract View article PDF
Perovskite solar cells (PSCs) have attracted significant scholarly attention in the field of photovoltaics due to their simple fabrication process and low cost. However, their potential for commercial use is limited by issues such as low power conversion efficiency (PCE) and instability. In this study, an approach for enhancing both the performance and life time cycle of perovskite solar cells (PSCs) by integrating biosynthesized silver nanoparticles (AgNPs) into the device structure was demonstrated. Unlike previous works that mainly focus on chemical synthesis of plasmonic nanoparticles, this method employs an eco-friendly biosynthesis route, offering a sustainable alternative. PSCs fabricated with varying AgNP concentrations (0–250 µL) exhibited significant improvements, with power conversion efficiency (PCE) increasing from 2.65% to 5.35%, and device lifetime extended by 69% relative to the control device. The observed enhancement is attributed to the plasmonic effects of AgNPs, which enhance light absorption, improve charge carrier extraction, and increase conductivity. This work highlights a promising strategy for the development of more durable and efficient PSCs through green nanotechnology.
Open Access
Development of a sixth-order active elliptic bandpass filter for cellular base station receiver and...
Atsuwe B Aondofa and Atser R Akpenongun
abstract View article PDF
This paper presents the design and simulation of a sixth-order active elliptic bandpass filter intended for cellular base station receiver and transmitter applications. The filter is designed to operate at a centre frequency of 2.65 GHz with a bandwidth of 100 MHz, employing a combination of elliptic filter synthesis and active filter design techniques. Simulation results yield a centre frequency of 2.653 GHz, a bandwidth of 100 MHz, and a passband gain of -35.124 dB. Additional performance metrics include a passband ripple of 0.5 dB, stopband attenuation of 60.145 dB, group delay of 2 ns, noise figure of 2.5 dB, insertion loss of 0.016 dB, return loss of 2.558 dB, and power consumption of 50 mW. The results confirm that the filter meets the required design specifications and is suitable for high-frequency, low-power applications in modern cellular infrastructure.
Open Access
Physics-Informed Neural Network for Solving 2D Steady Incompressible Navier-Stokes Equations: Appli...
Peter Anthony, Philibus M Gyuk and Isaac H Daniel
abstract View article PDF
This study explores the application of Physics-Informed Neural Networks (PINNs) to solve the two-dimensional steady incompressible Navier-Stokes equations, focusing on Poiseuille flow in a rectangular channel. Implemented using the DeepXDE library with a TensorFlow 1.x backend, the PINN embeds the governing partial differential equations and boundary conditions into its loss function. The neural network architecture consists of four hidden layers, each with 64 neurons. A hybrid optimization strategy, combining Adam (10,000 steps) and L-BFGS-B, ensured robust convergence. The composite loss function, comprising seven components (three for momentum and continuity equations, four for boundary conditions), decreased significantly, achieving a total test loss of 8.71×10^(-5) at step 9000. The predicted x-velocity component (u) was evaluated against the analytical Poiseuille solution, yielding an L_2 relative error of 0.0861 (8.61%). Visual comparisons confirm that the PINN accurately captures the parabolic velocity profile characteristic of Poiseuille flow. This work underscores the potential of PINNs as a data-efficient, mesh-free approach for solving fundamental fluid dynamics problems, paving the way for their application to more complex flow scenarios.
Open Access
Post-Quantum Cryptographic Frameworks for Internet of Things (IoT) and Internet of Medical Things (...
Thomas L Barna, Samson Isaac, Christopher Habu, Saratu Habu and Abimbola A Joseph
abstract View article PDF
The rapid advancement of quantum computing threatens the security of classical cryptographic
algorithms widely used in Internet of Things (IoT) and Internet of Medical Things (IoMT)
systems. Existing authentication mechanisms often struggle to balance quantum-resistant
security with the limited resources of edge devices. This study presents a lightweight
framework that combines lattice-based cryptography with adaptive optimization (QAuthIoMT) to ensure both quantum resilience and efficiency in constrained medical environments.
The framework incorporates three innovations: (1) an NTRU-based key establishment protocol,
leveraging the Shortest Vector Problem in polynomial lattices, (2) a hash-based authentication
mechanism with zero-knowledge proof verification, and (3) a genetic algorithm that
dynamically optimizes cryptographic parameters in real-time, based on device capabilities and
network conditions. Through extensive simulations using iFogSim with real-world datasets
(MIMIC-III, IoTBench) and NIST PQC benchmarks. The result demonstrates that QAuthIoMT achieves a Quantum Attack Resilience (QAR) score of 0.98, while reducing energy
consumption by 37% compared to PQCAIE and improving throughput by 2.1× over K3S-PQC.
The framework excels in heterogeneous environments, with minimal authentication delays and
low energy consumption for wearable devices. Formal verification with ProVerif confirms
99.8% resistance to man-in-the-middle attacks, while theoretical analysis proves security
against both classical and quantum adversaries. This work contributes three key advancements:
(1) an optimized NTRU implementation for medical IoT devices, (2) a novel integration of
metaheuristic optimization with post-quantum cryptography, and (3) comprehensive validation
across IoMT device classes. QAuth-IoMT provides a robust foundation for securing nextgeneration medical systems against quantum threats.
Open Access
Assessment of Occupational Radon Exposure and Associated Health Risks in Campus Facilities at Adama...
Abdulhamid M Suleiman, Adamu Yakubu, Jackson Karniliyus, Barnabas Benaiah and Kabiru Mohammed
abstract View article PDF
This study evaluates the radon (Rn-222) concentration and associated health risks in the Campus facilities at Adamawa State College of Education, Hong, Nigeria. Radon concentrations were measured in 20 locations, including offices, laboratories, and residential quarters, using active radon monitoring devices (RAD7). The results revealed radon concentrations ranging from 8.6 Bq/m³ at the Deputy Provost’s office to 53.1 Bq/m³ at the Geography Departmental office, with a mean concentration of 20.3 Bq/m³. The effective dose rate (ER) ranged from 0.005 WLM/y to 0.031 WLM/y, while the annual effective dose (Dy) varied between 0.1248 mSv/y and 0.7703 mSv/y. The excess lifetime cancer risk (ELCR) ranged from 0.0176% to 0.1086%, with the Geography Departmental office having the highest risk. Inhalation exposure (Einh) and lifetime cancer cases (LCC) were also calculated, with values ranging from 0.2994 mSv/y to 1.8487 mSv/y and 5.39 × 10?? to 3.33 × 10??, respectively. Radon concentrations, ELCR and Dy in most offices and staff quarters are within the World Health Organization (WHO) reference level of 100 Bq/m³ and the International Commission on Radiological Protection (ICRP) action level of 300 Bq/m³, 1.3% and 3 to 10 mSvy-1 for workplaces. However, the Geography Departmental office slightly exceeds the WHO reference level, warranting mitigation measures to ensure a safe working environment for staff and occupants.
Open Access
Deposition and Characterization of Antimony Tin Sulphide using Spray Pyrolysis
Awuzie C Laura, Uhuegbu C Chidi, Onoja J Ojonugwa and Nwigboji I Ajogu
abstract View article PDF
Spray pyrolysis is a method commonly used in aerosol processes for atomizing chemical precursors into aerosol droplets ready for dispersion in gas mediums to form thin films on passing through a hot reactor and getting evaporated. In this study, antimony tin sulphide was synthesized using spray pyrolysis, as it is a simpler and economical technique. Doping with antimony (Sb) showed a persistent decrease in band gap with an increase in Sb. Results showed that doping tin sulphide (SnS) with Sb enhanced the absorption spectrum of the SnS film by widening the absorption peaks of SnS (Sb) films, and consequently broadening the absorption band. The absorption spectrum of SnS film was extended from 424 nm (ultraviolet edge) to 493 nm, 517 nm, 516 nm and 512 nm (visible regions), respectively. This shows that Sb serves as an opaque material in the SnS (Sb) films, which absorb light more than transparent materials. Detailed information about the optical band gap was obtained using the dependence of the absorption coefficient on the photon energy. The bandgap was varied between 3.33 and 1.90 eV. Further results on antimony tin sulphide films at different annealing temperatures are presented. X-ray diffraction (XRD) showed a preferential peak of the plane (1 1 1) at 2? = 31.69, which was predominantly persistent in all the synthesized films. Scanning Electron Microscope (SEM), which showed the surface morphology of the synthesized SnS and SnS(Sb), indicates that the formed films were non-uniformly sparsely distributed grains, thus, depicting high-quality crystal films.
Open Access
First-Principle Study of Optical Properties in Erbium-Doped Fibres for Enhanced Optical Signal Ampl...
Umaru B Machu, Haruna Ali, Mohammed Y Onimisi, Joshua A Owolabi, Christiana O Akusu, Hassan G Muhamm
abstract View article PDF
The optical properties of silica, essential for applications ranging from fibre optics to UV transmission windows, are closely linked to atomic-scale defects, even though they are challenging to identify. Although electron paramagnetic resonance (EPR) has long been the predominant technique for defect analysis, this study employs time-dependent density functional perturbation theory (TDDFPT) to systematically examine the understudied optical signatures of erbium (Er)-doped silica (SiO2) and native defects (oxygen/silicon vacancies). The Er-doped systems (2.08–6.25% concentrations) and pure SiO2 along vacancy defects were simulated to compute transmittance, reflectivity, dielectric characteristics, and absorption. The results showed that the absorption peaks and imaginary dielectric function (?2) are redshifted by Er inclusion, with doping at 4.17% yielding the best improvement. Conversely, vacancy defects decrease otherwise because of increased absorption and reflection of the visible spectrum. These findings demonstrate how Er-doping can alter SiO2's optical response and emphasize the value of TDDFPT in connecting optical behaviour to defect patterns. This study advances the logical design of silica-based optoelectronic devices and offers a theoretical foundation for enhancing defect engineering in wide-gap semiconductors.
Open Access
Evaluation of Haematological Variation in Wistar Rat (Rattus Norvegicus) Associated with Radon Inge...
Oni A Adeola, Oni E Abiodun, Aremu A Adewale, Oyero O Peter, Oloyede Oluwaseun, Olaosun M Abayomi, L
abstract View article PDF
Numerous studies have been conducted on radon inhalation and its effects on oxidative stress parameters, but research involving radon ingestion and its haematological effects has not been reported. A total of one hundred and ten (110) albino rats weighing between 150 – 200 g each, consisting of fifty (50) non-pregnant females and 50 males, were used in this study. The rats were randomly assigned to four groups according to the study design. Exposed group rats were fed with newly collected radon-laden water (RLW) with an average radon concentration of 44333 Bq/m3 every day, while rats in Control Groups were given stream water, called control water (CW), with an average radon concentration of 1030 Bq/m3, throughout the experiment. After eight (8), sixteen (16) and twenty-four (24) weeks of radon exposure, respectively, six (6) rats were euthanized from Groups 1, 2, 3 and 4, after which the cervical dislocation was done to collect the blood samples. Blood samples were collected in an Ethylenediamine tetraacetic acid (EDTA) bottle for a haematological assay. The collected samples were taken to the laboratory to determine the values of WBC, ABS Platelet Count, Haemoglobin, and PCV using an automated haematology analyzer. Results with a t-test analysis at ? = 0.05 show significant differences in weeks 8 and 16, but more significantly in week 24. Therefore, the study highlights radon ingestion's potential to disrupt haematological parameters, emphasising the importance of mitigating radon exposure. Thus, it is crucial to supply drinking water that meets safety standards for radon levels to protect public health.
Open Access
General Relativistic Study of Motion of Comets Particles Elliptical Gravitational Field
Timothy Bulus, Chifu E Ndikilar, Halliru Ibrahim and Dayyabu Tafida
abstract View article PDF
Comets are small bodies consisting of aggregates of ice mixed with rock and dust. They are usually influenced by galactic forces and stellar encounters, and may have contributed to the formation of ice giants and transport gases across the solar system. Their orbits vary widely, and their frozen water sublimates around 3 AU, forming a coma, though some remain active beyond this distance. In this study, the line element in the gravitational field due to a static and ellipsoidal isolated gravitating mass point was used to study the motion of comets, and the relativistic equation of motion of an ellipsoidal mass was obtained via the metric tensor, affine connections and geodesics equation. The results show that the explicit equations of comets along the equatorial plane are second-order differential equations similar to reported results in the literature for different gravitational fields.
Open Access
Optical Thickness of Dielectric Layer in Solar Cell Design for Improved Efficiency: A Theoretical I...
Francis Aungwa, Kehinde Ogunmoye, Igba D Solomon, Peverga R Jubu, Abah A Oche, Eli Danladi, Newton F Gesa , Adebayo T Adepoju , Emmanuel J Adoyi and Michael B Ochang
abstract View article PDF
This study investigates the effect of varying dielectric layer thickness on the optical properties
of solar cells using MATLAB. Dielectric layers with thickness ranging from 10 to 100 nm were
analyzed across 200 to 1200 nm wavelengths. Results showed that absorption efficiency
increased with thickness, reaching a peak at 100 nm, where the absorption value was
approximately 0.9 at 600 nm. Reflectance stabilized around 0.45 to 0.50, while transmittance
was minimized to about 0.05, indicating that almost all incident light was absorbed or reflected
at this thickness. The highest efficiency recorded was 94.86%, confirming that the 100 nm
dielectric layer provided the best balance between absorption and reflectance. These findings
align with previous studies, which identified the 80–100 nm thickness range as optimal for
enhancing solar cell performance. This research highlights the importance of precise thickness
control in solar cell design to achieve maximum light absorption and device efficiency.
Open Access
Assessment of Natural Radioactivity and Radiation Hazard in Soil and Rock Samples from Mining Sites...
Michael C Ohakwere-Eze, Musa Nafiu, Shiv K Singh, Momoh Kabiru and John Simon
abstract View article PDF
We regret to inform the academic community that the article titled “Assessment of Natural Radioactivity and Radiation Hazard in Soil and Rock Samples from Mining Sites within North-Eastern Nigeria” by Michael C Ohakwere-Eze, Musa Nafiu, Shiv K Singh, Momoh Kabiru and John Simon, published in Physics Access, volume 4 issue 2 on the 18th of October, 2024, has been formally retracted. This decision was made following a thorough review, which identified ethical concerns and authorship disputes. Scientific integrity and academic honesty are fundamental to the advancement of knowledge. Retractions serve to correct the scholarly record and uphold these principles. We acknowledge the contributions of the authors and the editorial team, and we deeply regret any inconvenience this may cause to researchers who have referenced or relied on this work. The retracted paper will remain accessible in the journal’s archive, clearly marked as retracted, to ensure transparency and to prevent further citation of potentially unreliable findings. We appreciate the vigilance of the academic community in maintaining rigorous standards and encourage continued discussion on best practices in research. Should you have any questions or require further clarification regarding this retraction, please feel free to contact us.
Open Access
Investigation of Groundwater Contamination from the Use of Fertilizers, Pesticides and Herbicides o...
Afuwai G Cyril and Ema Abraham
abstract View article PDF
Fertilizers, pesticides and herbicides contain toxic chemicals which leach into groundwater bodies resulting in the generation of high Biological Oxygen Demand (BOD), and thus contaminating the groundwater system. In order to save the environment from further degradation, a geophysical investigation was carried out across agricultural lands at Kaura Local Government Area (LGA) of Kaduna State, Nigeria where prevalent use of fertilizer, pesticides and herbicides is a norm. The research aims to delineate areas of possible contamination plumes and their migration path. For this purpose, Electrical Resistivity Tomography (ERT) data were acquired along six (6) Traverses and the results were inverted using the RES2DINV Software. Distinct low-resistivity zones adjudged to represent the contamination plumes were obtained from the ERT results. Water samples collected from boreholes, hand-dug wells and river channels were also analyzed. The analyzed water samples results revealed that the total dissolved solids (TDS) ranged between (2.30x101 - 8.20x101) ?Scm-1 as against the Nigerian Standard for Water Quality (NSDWQ) value of 1x103 ?Scm-1. Biochemical Oxygen Demand (BOD), chemical oxygen demand (COD) and dissolved oxygen (DO) values ranged between 1-10, <2 - <98 and 0.01 - 0.12 mg/L respectively. The water samples had detectable levels of Cu, Cd, Ni, Mn, Pb and Zn contents which were below the permissible limits, and microbiologically revealed the presence of faecal contamination with bacteria pathogens such as Coliform and Escherichia coli, whose levels were above the acceptable limit while the mould yeast and total aerobic were below the permissible limit. Ultimately, the results obtained showed that the agricultural land constitutes a serious threat to groundwater bodies in the area.
Open Access
Impact of Yttrium Dopant on Physical Properties of Manganese Selenide Nanoparticles synthesized via...
Greatman M Onwunyiriuwa, Lebe A Nnanna, Nwamaka I Akpu, Young C Ahameful and Maxwell O Akpu
abstract View article PDF
Undoped and yttrium-doped manganese selenide thin films were synthesized via spray pyrolysis deposition technique for photovoltaic purposes by utilizing manganese (II) acetate tetrahydrate, selenium (iv) oxide and yttrium. The deposited samples were characterized with instruments such as X-ray diffractometry, Uv-Vis spectrophotometry, four-point probe and SEM/EDX for structural, optical, electrical and morphological analysis. The X-ray diffraction pattern for both undoped and Y-doped MgSe samples shows the presence of crystal peaks along (111), (200), (210), (211) and (300) planes indicating polycrystalline and hexagonal structural nature. Optical analysis reveals a decrease in absorbance and an increase in transmittance as the wavelength increases for all the samples. The addition of a higher percentage (0.04 mol%) of yttrium dopant narrowed the bandgap energy (1.15 eV) of the undoped MnSe, making these materials promising for solar cell fabrication. Electrical analysis reveals that as yttrium dopant concentration in MnSe increases from 0 to 0.04 mol%, the film thickness increases from 110.0 nm to 115.13 nm with increasing resistivity and decreasing conductivity of 11.68 x 10-4 to 11.68 x 10-4 ?.m and 8.561 x 102 to 8.467 x 102 (?.m)-1 respectively. The overall electrical result of both undoped and y-doped MnSe conforms to that of a typical semiconductor. For the morphology result, the addition of yttrium dopant altered the microstructure of undoped MnSe. For undoped MnSe a smooth dense layer was observed while Y-doped MnSe reveals an agglomeration with no defined shape but is also dense. EDX result confirms the growth of a novel yttrium manganese selenide (YMnSe) thin material. YMnSe films offer features like narrowed band gap energy, improved charge transport characteristics and enhanced light trapping, making them potential materials for photovoltaic applications.
Open Access
Delineation of Groundwater Aquifer and Subsurface Structures of Some Selected Areas in Chikun Local...
Adeka Patience, Cyril G Afuwai, Matoh D Dogara, Garba M Ephraim, Magaji Simon and Ezra Dauda
abstract View article PDF
This study is aimed at delineating groundwater aquifer and subsurface structures of some selected areas within Chikun local government area of Kaduna State, Nigeria, using the Vertical Electrical Sounding (VES) method. To obtain the electrical resistivity values of the subsurface within the study area, electric current was conducted into the ground through two current electrodes while measuring the corresponding values of the potential difference using two potential electrodes. VES was conducted in twenty (20) different stations and was named profiles A, B, C and D with each having five stations with several layers, and four Vertical Electrical Sounding curves which were A, H, Q and QH were obtained. The results obtained from Vertical Electrical Sounding (VES) revealed the aquifer was at depths 7.3 m, 0.141 m 22.7 m, and 14 m for VES A, B, C and D respectively. Results from the 2D map revealed low resistivity within the weathered basement and fracture basement with resistivity values ranging between 1.929 – 885 ?m which correlates with the results obtained from the VES. The reflection coefficient (r) was used to determine the aquifer protective capacity of the study area and the isoresistvity map depicted that 7% was good (with r values ranging between 0.8 – 4.9), 43% was moderate (with r values ranging between 0.2 - 0.79), 33% was weak (with r values ranging between 0.10 - 0.19) and 17% was poor (with r values <0.10). Aquifer with low reflection coefficient values (r<0.8) favors groundwater potentiality but with high vulnerability to contamination. The study area has an aquiferous zone characterized by fractures and porosity aiding groundwater permeability and storage
Open Access
Radon Gas Risk Indices in Water on Fractured Basement of Ayetoro Housing Scheme, Oyo
Emmanuel A Oni, Johnson A Abilawon, Oluwaseun O Oloyede, Abraham A Aremu, Olukunle O Oladapo, Temita
abstract View article PDF
Radon gas, a naturally occurring radioactive element, presents significant health risks, particularly in areas with fractured basement geology, where subsurface characteristics can elevate its concentration. As the second leading cause of lung cancer globally, after smoking, radon exposure is a critical public health concern. This study seeks to evaluate the concentration levels of radon gas, analyze its potential health risks to the residents, and provide insights into the environmental factors influencing radon accumulation in this area. Thirty (30) samples were collected for groundwater from various locations within the study area. Groundwater samples were collected from selected drinking water sources using 1.5 litre plastic bottles. Radon gas concentration was measured using a RAD7 electronic radon detector for soil and RAD7 H2O for groundwater. The data obtained was analysed using a statistical tool to perform a one-way Analysis of Variance (ANOVA). The samples were also subjected to decay corrections to ensure the accuracy of the results. The data were analysed using descriptive and inferential statistics, with statistical significance set at p<0.05. Groundwater radon concentrations ranged from 0.576Bq/L to 6.54Bq/L with a mean concentration value of 2.81 Bq/L and a standard deviation of 1.73 Bq/L. The mean annual effective dose for radon due to inhalation, ingestion and whole- body are 0.0254 mSvy^(-1), 0.00987 mSvy^(-1) and 0.0352 mSvy^(-1) respectively. The results were all below the recommended threshold of 0.1 mSvy^(-1) set by the World Health Organization (WHO). The Excess Lifetime Cancer Risk (ELCR) value of 12.34 × 10^(-5) was obtained which corresponds to about 1.23 in 10,000 risk of developing cancer over a lifetime due to radon exposure through water. The study on radon concentration in groundwater from the Ayetoro Housing Scheme, Oyo, found an average radon level of 2.82 Bq/L, below the EPA's maximum contaminant level (MCL) of 11.1 Bq/L. This indicates that residents in the area are not at significant risk from radon exposure at the time of the study. However, it was observed that inhalation of radon from water presents a higher radiological hazard than ingestion. The study recommends regular radon monitoring in the area to ensure continued safety.
Open Access
Profiling the Properties of SILAR Synthesized MnSe Films as Potential Material for Absorber Layer o...
Asielue O Kingsley, Opene J Nkechi and Okoli N Livinus
abstract View article PDF
This study investigates the optical, structural, and electrical properties of manganese selenide (MnSe) thin films synthesized using the Successive Ionic Layer Adsorption and Reaction (SILAR) method, with varying volumes of triethylamine (TEA) as a complexing agent. The MnSe films exhibited high absorbance in the ultraviolet (UV) region, peaking at values from 0.61 to 0.91 depending on TEA concentration, and declining towards the near-infrared (NIR) region. Transmittance varied from 12.53% to 92.17%, decreasing with higher TEA concentrations. The energy band gap of the films decreased from 2.90 eV with 2 ml of TEA to 2.30 eV with 10 ml, highlighting the tunability of MnSe for photovoltaic applications. Film thickness varied from 190.82 nm to 381.63 nm, reflecting a direct relationship with TEA concentration. Structurally, the MnSe films crystallized in the cubic phase with improved crystallinity and reduced defects at higher TEA volumes, as evidenced by a crystallite size increase from 20.10 nm to 25.09 nm and decreased dislocation density and microstrain. Morphological analysis revealed uniform grain-like structures at moderate TEA concentrations, which are optimal for photovoltaic performance. The electrical properties highlighted a trade-off between resistivity and conductivity. Films deposited with lower TEA volumes exhibited higher electrical conductivity of 2.72 ×10^(-5) S/cm at 2 ml compared to 1.02 ×10^(-5) S/cm at 10 ml. These findings confirm the suitability of MnSe thin films for absorber layers in solar cells, particularly where tunable optical and electrical properties are desired. The ability to control these properties by varying TEA concentration enhances the material's versatility for applications beyond photovoltaics, including optoelectronic and photodetector devices.
Open Access
Delineating Hot Zone and Lineaments within Vredefort Crater in South Africa through Aeromagnetic Da...
Muhammad B Atif, Yongzhi Wang, Muhammad P Akhter, Bello Y Ayoola, Lawal K Muideen, Fahad Hameed, Kateryna Hlyniana, Bo Wen , Zubair Nabi , Dong Yuhao and Yakubu M Bashir
abstract View article PDF
The Vredefort Dome has undergone some geologic processes that result in changes in the temperature of the rocks. This study contributes to the discussion on the thermal effect of the impact in the area on a regional scale and also delineates the linear structures around the Dome. The outcome shows that the center of the Dome is characterized by a low Curie point depth (CPD), indicating a high-temperature status that agrees with previous temperature reports in that area. The high-temperature tendency is observed to extend south of the Vredefort dome. The center-south of the Vredefort structure has a high thermal gradient and heat flow. The fractal distribution of the Vredefort structure correlates with the multi-ring structure around the Dome, which is peculiar to a few impact structures on Earth. The trend of the Fractal exponent contour around the center suggests that the contact of the meteoritic body at that region occurs at an angle and then pushes southwards. The structural analysis results show linear structures that are believed to be faults/fractures trending in North-NorthEast (NNE), NorthEast (NE), EastWest (EW), and NorthSouth (NS) directions whose effects have been explained in previous works in the area and were also identified on the ground. Some closures are observed at the center of the multi-ring structure, indicating the melt-dykes around the Vredefort dome. The Euler depth solutions cluster suggests the lineaments are about 7 km deep.
Open Access
Enhanced Photovoltaic Features of Tin-doped Cobalt Molybdate Nanostructure Materials
Ijeh Rufus and Imosobomeh L Ikhioya
abstract View article PDF
In this study, Sn-doped Cobalt molybdate was synthesized via an electrochemical deposition technique to enhance photovoltaic application. The Sn-doped CoMo has diffraction angles of (36.58°, 34.67°, 47.21°, 61.52°, 65.32°, 71.35°, and 75.67°), which correspond to the Miller indices (111, 211, 200, 211, 212, 300, and 311). Each peak, denotes a distinct crystal structure, indicating a polycrystalline material. A redshift indicates a smaller band gap, whereas a blueshift suggests a larger band gap. CoMo and Sn0.3@CoMo have low visible absorbance, whereas Sn0.1@CoMo and Sn0.2@CoMo have higher absorbance, making them better suited for photovoltaics, solar cells, photocatalysis, and energy storage applications. CoMo shows semiconductor qualities due to its 2.11 eV bandgap. The bandgap drop to 1.92 eV indicates that Sn caused extra energy levels in the bandgap. The FTIR spectrum of CoMo contains peaks related to metal-metal bonding and Mo-O vibrations. The bands between 600-800 cm-¹ (Mo-O stretching) and 1000-200 cm-¹ (Co-O stretching). Introducing Sn at a low concentration (0.1) causes modest changes or broadening of the existing peaks. The peaks at 300-400 cm-¹ indicate Sn-O vibrations.
Open Access
Assessment of Heavy Metal Contamination of Coal Deposits in Kogi State, Nigeria using Instrumental ...
Felix O Uloko, John C Agomuo and Matthew N Agu
abstract View article PDF
In this study, the concentration of heavy metal contaminants in the coal samples from selected coal mining sites in Okobo, Odagbo, Ofugo and Opoko-Obido, within Kogi State, Nigeria were identified and determined using the Instrumental Neutron Activation Analysis Technique. Four samples were collected from the mining sites at 0 – 5 cm, and 5 – 10 cm below the soil surface. The range of the concentrations of heavy metal in the samples are V (6.03 ± 0.66 to 18.40 ± 1.10), Mn (6.06 ± 1.17 to 273 ± 2), As (0.18 ± 0.02 to 0.33 ± 0.04), U (0.57 ± 0.05 to 0.74 ± 0.05), Cr (7.14 ± 1.62 to 16.60 ± 1.80), Co (1.49 ± 0.16 to 9.10 ± 0.33), Sr (312 ± 71 to 383 ± 107), Sb (0 to 0.17 ± 0.05), Ba (0 to 174 ± 19) and Th (1.30± 0.09 to 2.39 ± 0.11). These values of Mn, Sr and Sb are slightly higher than the National Environmental Standards and Regulations Enforcement Agency and the United States Environmental Protection Agency permissible limits of 150 mg/kg, 300 mg/kg and 3.0 mg/kg respectively. The study revealed that the coal from the mines was contaminated with heavy metals especially Sr, Ba, and Ti thereby posing stern environmental and health concerns.
Open Access
Investigating the Impact of Voltage on Optoelectronic Features of Silver Incorporated into the Latt...
Shaka O Samuel, Ernest O Ojegu and Imosobomeh L Ikhioya
abstract View article PDF
This research aims to enhance the optoelectronic properties of Ag-doped ZrS through
electrochemical deposition. Different characterization techniques were employed to examine
the optical, structural, and morphological properties of the synthesized material, with results
showing that the absorbance of ZrS and Ag-doped ZrS changes with the applied voltage,
enhancing carrier concentration and mobility at higher voltages to enhance absorption
properties. ZrS displays a bandgap energy of 2.00 eV, showing its potential as a semiconductor
material, while Ag-doped ZrS results in higher bandgap energies between 2.15 eV and 2.50 eV,
leading to modifications in its electronic characteristics. The crystal planes of 101, 103, 111,
and 112 are identified by precise 2? angles of 23.59°, 34.91°, 48.42°, and 62.62° for ZrS and
19.64°, 33.61°, 44.48°, and 63.31° for Ag-doped ZrS. Altering voltages (10, 12, 14 V) affect
the electrical structure in XRD analysis, influencing peak positions and intensities. A more
evenly distributed Ag layer, preserving surface smoothness, results from lowering the voltage
while introducing Ag. The interaction of Ag and ZrS leads to localized structural changes. As
the voltage increases, the surface roughness of Ag-doped ZrS increases more than the undoped
ZrS. The resistivity values decrease as the voltage increases, suggesting enhanced conduction
and more charge carriers. The increased conductivity values (4.34, 4.58, 4.71 and 4.78 S/m)
indicate that higher voltage enhances conductivity, benefiting applications needing efficient
charge transfer
Open Access
Delineating Potential Hydrocarbon Targets Through Aero-Radiometric Techniques
Bello Y Ayoola, Mohammed B Yakubu and Muhammad A Bilal
abstract View article PDF
The discovery of more hydrocarbon wells remains a major recipe to boost the economy of Nigeria, a major oil producer in Africa. The seismic method is prominent for identifying traps in the oil explorations, but cannot indicate if the trap host hydrocarbon. This gap is usually filled by the radiometric method, its characteristics around the Kolmani well 1 have hitherto not been reported. This research focused on identifying promising locations for hydrocarbon accumulation around the Kolmani Well 1 while using the well as a control. To achieve the objectives of this research, the nature of the radioelements was observed over the Kolmani well1 and the outcome of normalizing potential and uranium was also identified. The average values of potassium (K), thorium (Th), and uranium (U) are 0.277%, 8.917 ppm, and 1.431 ppm respectively. The concentration of the three radioelements, K, Th, and U, decreases over the oil well. This was ascribed to enhanced leaching of natural radioelements caused by hydrocarbon-generated groundwater acids. The result of the normalization of K with Th yields a low concentration of K over the Kolmani well1 and the normalization of U with Th yields a high concentration of U over the Kolmani well1. These were in tandem with the report on the application of the method in previous locations. Hence, the results of the normalization of K and U were used to identify four locations with potential for hydrocarbon exploration. The viability of these locations was confirmed with the positive DRAD (Delineation of Radiometric anomalies) value (ranging from -5.1 to +5.2), a pointer to hydrocarbon accumulation in an area, recorded in these locations and the location of the Kolmani well 1.
Open Access
Assessment of Trace Elements Concentration in Selected Vegetables from High and Low Cancer Prevalen...
Joshua O Ojo, Danjuma D Maza, Grace O Akinlade and Osualale P Taiwo
abstract View article PDF
This study investigates the potential link between cancer incidence and trace elements and heavy metals intake from locally grown vegetables in Ondo West and Ondo East Local Government Areas of Ondo Stae, Nigeria. It builds on a 2019 study by Adeola and colleagues, which identified a significantly higher cancer incidence in Ondo West compared to Ondo East, with rates three times higher. Five commonly consumed vegetables—Solanum macrocarpon, Talinum triangulare, Amaranthus hybridus, Telfairia occidentalis, and Vernonia amygdalina—were sampled from 47 locations across both regions. The samples were oven-dried, digested, and analyzed using atomic absorption spectroscopy (AAS) to determine the mean concentrations of essential trace elements (magnesium, manganese, and zinc) and toxic heavy metals (lead and cadmium). The estimated daily intake (EDI), daily intake (DI), and chronic daily intake (CDI) were calculated and used to assess the incremental lifetime cancer risk (ILCR), non-cancer hazard quotient (HQ), and non-cancer health index (HI). Contributions to the recommended daily intake of magnesium, manganese, and zinc through vegetable consumption were 12.65%, 40.8%, and 9.6%, respectively, in Ondo West, and 13.7%, 47.7%, and 10.58%, respectively, in Ondo East. The total non-cancer health indices were 0.90 and 0.92 for Ondo West and Ondo East, respectively, indicating no significant non-cancer health risks from consuming these vegetables. However, the ILCR values were calculated as 0.000293 for Ondo West and 0.000416 for Ondo East, exceeding the threshold of 1.0 × 10??, suggesting a potential cancer risk. Despite this finding, the study could not account for the notably higher cancer prevalence in Ondo West.
Open Access
Assessment of Activity Concentration and Health Hazards of Radiation Exposure in Soil from Mamara J...
Joseph I Abaleni and Agu M Nnamdi
abstract View article PDF
Natural background radiation exposure is an inevitable occurrence on Earth, and humans are exposed to radiation in their surroundings whether consciously or unconsciously. However, increased artisanal and illegal mining could harm the local environment and increase background radiation levels, affecting the community's overall health. This study assessed the activity concentration of primordial radionuclides (226Ra, 232Th, and 40K) from soil samples obtained from Mamara Jidda and Waja tin mine sites in Nasarawa State, Nigeria, and its risk to human health. The gamma spectroscopy using a Sodium iodide-thallium activated detector was used to measure the activity concentrations of primordial radionuclides in the surface soils/sediments samples. The activity concentrations of 226Ra, 232Th, and 40K for Mamara Jidda and Waja were found to be within the range of 4 - 18 Bq kg-1, 41 - 105 Bq kg-1, and 524 - 717 Bq kg-1; 13 - 40 Bq kg-1, 75 - 134 Bq kg-1, and 591 - 882 Bq kg-1 respectively. The average values show that 40K and 232Th concentrations are above the recommended limit set by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) in Mamara Jidda and Waja mine sites. The annual gonadal dose equivalent (AGDE), annual effective dose rate (AEDE), radium equivalent (Raeq), absorbed dose rate (D), and external hazard index (Hex) for Mamara Jidda and Waja were found to be 0.56 mSv yr-1, 0.10 mSv yr-1, 588.58 Bq kg-1, 78.26 nGy hr-1 and 0.46; 0.73 mSv yr-1, 0.13 mS yr-1, 742.74 Bq kg-1, 103.72 nGy hr-1 and 0.61 respectively. The AEDE and Hex are below the recommended safety limits. However, the high values of AGDE in both mining sites and D in Waja mine demonstrate that with continuous exposure to radiation, a significant genetic impact is eminent to the miners and inhabitants of these areas. Also, the Raeq values for both mines suggest that their soils are unsafe for use as building materials.
Open Access
Radiological Risk Assessment of Building Materials Used in Federal College of Education (Technical)...
Olufunmilayo O Alatise, Tolulope O Aluko and Ayotunde A Ajayi
abstract View article PDF
Multiple building constructions necessitating a regular influx of different soils for building purposes within Federal College of Education (Technical) Akoka, in Lagos State, Nigeria spurred a radiological risk assessment of selected soil samples. Five (5) construction points were identified and ten (10) soil samples were collected. A gamma spectrometer was used to evaluate the natural radionuclides (226Ra, 232Th, and 40K) present in the soils. IAEA-certified standard materials of RGU-1, RGTh-1, and RGK-1 were used to determine the full peak efficiencies of gamma energies 609, 1120, and 1764 keV for 238U, 2614 keV for 232Th and 1460 keV for 40K. Activity concentration, absorbed dose, annual effective dose equivalent, hazard indices, and excess lifetime cancer risk (ELCR) were estimated to assess possible radiological risks in the building soil samples. Results from the analysis revealed the highest radioactivity among soil samples was 674.3 Bq/kg from 40K and the lowest was 18.5 Bq/kg from 226Ra. The absorbed dose (D) varies from 65.8 nGy/h to 215.3 nGy/h with an average value of 136.6 nGy/h, and the annual effective dose equivalent ranged from 0.081 mSv/y to 0.264 mSv/y with an average value 0.168 mSv/y. The internal and external hazard index ranged from 0.49 - 1.46 and 0.39 - 1.32 respectively which is not completely below the hazard index threshold value ?1 as recommended by UNSCEAR. The ELCR values ranging from 0.222 × 10-3 - 0.726 × 10-3 with an average value of 0.461 × 10-3 predicted an insignificant carcinogenic risk with the probability of four persons in every 10,000 persons.
Open Access
First Principle Investigations of Structural, Electronic and Thermal Properties of Pristine, Metal ...
Abdulkadir S Gidado, Reuben A Solomon, Lawal Abubakar. Faiza Ahmed and Sulaiman R Haladu
abstract View article PDF
Silicene, a two-dimensional hexagonal silicon layer, exhibits exceptional electronic and
thermoelectric properties. However, its application in semiconductors is hindered by its zeroband gap, which could be overcome by modifying its electronic properties through doping. In
this paper, Density Functional Theory (DFT) calculations were performed to investigate the
band gap opening in silicene by studying the effect of magnesium and sulphur doping on its
electronic, structural and thermal properties. Pristine silicene has a lattice constant of 3.86 Å
and a zero-band gap. Upon doping with 12.5% S and Mg atoms, the lattice constant modifies
to 3.45 Å and 3.93 Å, respectively, resulting in a direct band gap opening. For 25% Mg and S
doping, the result shows that Mg and S effectively alter the band structure and the band gap of
silicene monolayer at various configurations. The maximum band gap was 0.98 eV and 1.22
eV for Mg and S doping into the meta position to the reference point R, respectively. The power
factor significantly increases with doping, reaching 1.20 x 1011 WK-2m-1 and 1.40 x 1011 WK-
2
m-1 for 12.5% Mg and S doping compared to 7.4 x 1010 WK-2m-1 for pristine silicene. This
substantial enhancement indicates improved thermoelectric performance, making silicene a
promising candidate for thermoelectric applications. Results demonstrate that tuning the band
gap through doping can simultaneously enhance the power factor, highlighting the potential of
Mg/S-doped silicene for efficient energy harvesting and conversion.
Open Access
Assessing Ionizing Radiation Exposure Risks to Human Health in Wadi-B, Jere Oil Exploration Areas, ...
Ali Yakubu, Tijjani Hassan Darma, Usman M Ibrahim, Aminu Maitama, Saidu Suleiman Zarma, Umar Muhamma
abstract View article PDF
Ionizing radiation, emanating from decaying nuclides, poses potential biological harm to
human organs. Wadi B, a village within the Jere local government area of Borno State, Nigeria,
is currently undergoing oil exploration activities. This study was conducted to evaluate the
outdoor gamma radiation levels at the Wadi B oil exploration site. Utilizing a portable hand
dosimeter (Radiation Alert Inspector), gamma exposure levels (GEL) were measured across
sixteen (16) spots within the exploration site. Results revealed that the gamma exposure levels
measured in the boreholes FYM (1 to 8), range from 0.17- 0.27 Mr/hr, with an average of 0.21
Mr/hr while, the levels around the wells FYM (9 to 16) vary from 0.14- 0.25 Mr/hr, with an
average of 0.18 Mr/hr. The estimated annual effective dose (AED) varied from 0.24528 to
0.47304 ?Sv/yr, averaging at 0.3460 ?Sv/yr. Notably, the average values of Total Dissolved
Solids (TDS), Conductivity, and Gamma radiation exceeded the recommended limits
established by the World Health Organization (WHO, 2006), which are 400 ?S/cm for
conductivity, (50-150) ppm for TDS, and 0.002 mR/hr for radiation doses, respectively.
However, the calculated Excess Lifetime Cancer Risk (ELCR) values were lower than the
proposed world average level of 70 ?Sv/yr by the United Nations Scientific Committee on the
Effects of Atomic Radiation (UNSCEAR). This study suggests a heightened risk of exposure
to outdoor ionizing radiation among inhabitants residing near the study locations.
Open Access
First Principle Study of Structural, Electronic, Mechanical and Optical Properties of Bulk Niobium ...
Jabir A Tahir, Godwin J Ibeh and Alhassan Shuaibu
abstract View article PDF
An intensive study on structural, electronic mechanical and optical properties of bulk Niobium Dichalcogenides NbX2 (X=S, Se) was carried out using the first principle. The structural parameters such as Equilibrium Lattice Parameters, Volume, Bulk Modulus, and First-Derivative Modulus were calculated to determine if the materials are energetically stable. Elastic constants were further obtained from which mechanical properties i.e. bulk, Young's and shear moduli and consequently Poisson's ratio were obtained. Based on the well-known Born stability conditions Bulk-NbS2 is most likely mechanically anisotropic ductile material. While Bulk-NbSe2 for the predicted B/G ratio in all three methods is less than a critical value of 1.75, hence this shows that NbSe2 is a brittle material exploring its electronic and optical properties whose motivation was to find out the most stable phase and ascertain if these materials could be used in various fields that suit their mechanical and optical properties. Furthermore, from the calculated optical spectra, plasma frequencies were analyzed which indicated the possibility of applying the material in plasmonic-related fields.
Open Access
Implications of Solar Wind Disturbances on Forbush Decrease
Ogochukwu C Nwuzor, Austin Ojobeagu, Augustine Chikwendu, Patricia Otah, Cyril Ozibo and Chukwuemeka
abstract View article PDF
This study investigated the role of solar wind disturbances on variations in cosmic ray intensity.
To conduct the study, use was made of the data on cosmic rays from the SOPO, CLMX, and
MOSC neutron stations, as well as solar wind speed data from 2000 to 2005. The source
Forbush decrease (FD) dates were generated from onset journal publications, specifically the
FD list of Dumbovi ?c et al., (2011). The manual method of FD selection was used to identify
FDs. The FD dates, computed magnitudes, and solar wind speed data were recorded and
presented. From the study, FDs were generated, some of which were of the same date as those
in the source table, while others were not observed in the source table. FDs not observed in the
source table were generated and catalogued by this research. It was also observed that the
magnitude of FDs generally depends on the coordinates of the observing neutron stations. A
strong correlation with a value of cc = 0.93 was observed between FDs of SOPO and MOSC
stations, followed by FDs of CLMX and MOSC stations of value cc = 0.89, and lastly, FDs of
SOPO and CLMX stations of value cc = 0.74. This implies that observed FDs from neutron
stations are coordinate-dependent. The correlation between FD magnitudes and solar activities
shows that solar wind had a high and significant correlation with FD magnitude to the tune of
cc = 0.54. Based on the findings, the study concludes that solar wind disturbances play a crucial
role in causing a sharp decrease in the intensity of cosmic rays known as Forbush decrease.
Open Access
Assessment of Radon Concentration in some Selected Water Sources at Kiyawa Town, Kiyawa, Jigawa Sta...
Haruna Y Shuaibu, Yusuf Shuaibu, Umar M Dankawu, Ali Yakubu, Yakubu Mohammed, Abdulhaqq A Olaide, Sa
abstract View article PDF
In this study, an assessment of Radon concentration in some selected water sources from
Kiyawa town, Kiyawa local Government area, Jigawa state, Nigeria was conducted. The results obtained show that the concentrations of Radon in the water samples ranged from 32.152 to 43.891 Bq/L, with mean values of 37.78 Bq/L and 35.13 Bq/L for well and borehole water
respectively. These results were compared with the world average Maximum Contaminant Level (MCL) of 10 Bq/L set by the World Health Organization (WHO), and it was observed that 60% of the recorded Radon concentrations, alongside the mean values for both water types, exceeded the WHO's recommended MCL of 10 Bq/L, as well as the MCL of 11.1 Bq/L set by the United States Environmental Protection Agency (USEPA) in 1991. However, all mean values were below the recommended action level of 100 Bq/L set by the European Commission (2001/928/Euratom) for public water supplies, and WHO in 2008. Also, all the mean values of the annual effective doses exceeded the recommended level of 0.1 mSv/year set by the WHO.
Consequently, it is recommended that the inhabitants of Kiyawa town boil their water, regardless of its source, before drinking to reduce Radon concentrations in the water.
Open Access
Plasmonic Photo-Electrode with AgNPs as Artificial Nano-Antenna for Enhanced Performance in Perovsk...
Nicodemus Kure, Daniel I Hyuk, Eli Danladi and Dogara M Dary
abstract View article PDF
The introduction of noble metal nanoparticles in solar cells has been proven to enhance the
performance of perovskite solar cells. In this study, silver-modified photoanodes were utilized to improve the performance of perovskite solar cells through successive ionic layer adsorption
and reaction (SILAR) procedures. Due to the surface plasmon resonance effect, the light
trapping capacity of the device was enhanced with superior photovoltaic properties. The
plasmonic effects of the introduced silver nanoparticles (AgNPs) were explored using SEM, XRD, UV-visible absorption spectrophotometer and solar simulator. The SEM results show
compact morphologies and shinning surfaces indicating the presence of AgNPs. The XRD
result shows a good crystal phase. The UV-vis results show enhanced optical absorption with
AgNPs incorporation. The photovoltaic characteristics of the fabricated PSCs are: (i) pristine device; Jsc of 6.440 mA/cm2, Voc. of 0.948 V, FF of 0.642 and PCE of 3.917%, (ii) device with 1 SILAR of AgNPs; Jsc of 014.426 mA/cm2, Voc. of 0.949 V, FF of 0.642 and PCE of
8.795%, and (iii) device with 2 SILAR of AgNPs; Jsc of 10.815 mA/cm2, Voc of 0.917 V, FF
of 0.558 and PCE of 5.536%. The device with the best performance is made of 1 SILAR cycle of AgNPs which shows an enhancement of ~2.245 times in PCE, ~2.240 times in Jsc and ~1.001 times in Voc over the reference device. The results in this study have unlocked the beneficial role of AgNPs and further contribute to understanding surface plasmon effect due to AgNPs introduction.
Open Access
Preliminary Assessment of Thermal and pH Properties of Soils in Ogoniland, Rivers State, South-Sout...
Mohammed Maina, Othniel K Likkason, Nuhu K Samaila and Sani Ali
abstract View article PDF
Soil temperature and its variations at different depths are unique parameters that contribute to
the understanding of both surface energy processes and regional environmental conditions. This
study reports the effects of oil and gas exploration (pollution) on soil thermal properties in
Ogoniland, Rivers State, Nigeria. The scope of this study is limited to the determination of the
temperature and pH of the soils. A total of thirty (30) soil samples were collected randomly
using vegetation, slope, and altitude factors from three (3) local government areas of
Ogoniland, Rivers State, Nigeria for determining the point for each sampling, coordinates, and
elevation. Soil samples were collected at two depths: 0-15 cm (Topsoil) and 15 – 30 cm
(Subsoil) with the aid of a Dutch stainless steel hand auger from four (4) sites (impacted) at
different locations within the study area and one (non-impacted) control site outside the project
area. A standard digital soil thermometer was employed to determine the temperature of the
soils in situ in both regions. It has been observed that the pH and temperature of soils in situ
and their variation with test points (location) agree with the results reported in these and similar
environments. Hence, it can be concluded that the soils in Eleme, Gokana and Tai Local
Government Areas may be recommended, but, with caution, for agricultural activity, laying of
gas pipelines, or buried cable in the areas, since the values of these properties observed were
within the range of standard values.
Open Access
Determination of Structural, Electronic, and Elastic Properties of SnTiO3 using Density Functional ...
Abdulkadir M Nura, Sulaiman R Haladu, Abdulkadir S Gidado, Lawal Abubakar and Reuben S Abraham
abstract View article PDF
The harmful effect of lead Pb2+ base materials like PbTiO3 on the environment and human
health has raised ecological concerns, which has led to the investigation of lead Pb2+ free
ferroelectric materials that are safe for the environment and human health and can be used in
technological applications. In this research, the structural, electronic, and elastic properties of
the cubic phase of SnTiO3 were investigated using first principle calculation. The electronic
structure calculation was done by using the generalized gradient approximation and PerdewBurke Ernzerhof (GGA-PBE) functional as implemented in the pseudopotential plane wave
approach within the framework of density functional theory (DFT) by using Quantum Espresso
open sources computer code. The convergence test of total energy concerning energy cut-off
wave function and k-point sampling was performed to ensure the accuracy of the calculations.
Thermo_pw code was employed to compute the elastic constant using the Quantum Espresso
software package and the result obtained was used to calculate mechanical parameters such as
the elastic properties, anisotropy factor A, shear modulus G, bulk modulus B, Young’s modulus
E, and Poison’s ratio n of the SnTiO3. Furthermore, Debye temperature and longitudinal and
transversal sound velocities were determined using the elastic constant. Therefore, the cubic
phase of SnTiO3 with a space group of (Pm3m) is a good ferroelectric material due to its Debye
temperature and the covalent bonding nature of the atom within the solid crystal of the material.
Open Access
Assessment of Heavy Metals, Gross Alpha, Gross Beta and Radon Activity Concentration in Groundwater...
Abubakar Ahmad, Koki F Salmanu, Ibrahim Y Yola, Idris D Adamu and Ali Yakubu
abstract View article PDF
This study assessed the activity concentrations of gross alpha, gross beta, Radon and heavy
metals in groundwater sources from illegal mining areas in Doguwa Local Government, Kano
State, Nigeria. Water samples from five distinct mining areas were analyzed for gross alpha
and beta radioactivity using a portable single-channel gas-free proportional detector
(MPC2000B-DP) via ISO9696 and ISO9697 methods, Radon levels with a Rad7
(DURRIDGE) detector, and heavy metals with atomic absorption spectroscopy. Gross alpha
concentrations ranged from 0.0000238 to 0.00013 Bq/L, averaging 0.00008158 Bq/L, a value
below the WHO limit of 0.5 Bq/L. Gross beta concentrations ranged from 0.536 to 2.78 Bq/L,
averaging 1.7056 Bq/L, exceeding the WHO limit of 1.0 Bq/L. Radon levels varied from 0.12
to 1.7 Bq/L, averaging 1.102 Bq/L, below the WHO limit of 11.1 Bq/L. Annual effective doses
from gross alpha ingestion were 4.10918E-05, 4.16874E-06, and 8.33748E-06 mSv/year for
adults, infants, and children, respectively. Radon exposure doses were 1.61E-13 and 8.04E-14
mSv/year for adults and children, respectively, below the 0.1 mSv/year limit. However, beta
radiation doses exceeded the 0.1 mSv/year limit, with values of 0.85911072, 0.21477768, and
0.42955536 mSv/year for adults, infants, and children, respectively. The average
concentrations of heavy metals were 0.00058 mg/L for Cd, 0.012 mg/L for Cr, 0.00628 mg/L
for Fe, 0.0046 mg/L for Mn, 0.09534 mg/L for Ni, 0.01214 mg/L for Pb, and 0.00582 mg/L for
Zn. Children exhibited elevated cancer risks from heavy metal ingestion 0.004865 and dermal
exposure 0.000069, with hazard quotient values of 0.740205 and 0.004882, respectively. The
hazard index and lifetime cancer risk for children were 0.004882, exceeding USEPA
recommended values. While gross alpha and radon levels were within safety limits, beta
radiation levels and heavy metal hazard quotients exceeded maximum contamination levels,
highlighting significant health risks, including DNA damage and increased cancer risks.
Open Access
Assessment of Radon Concentration in Groundwater with Associated Human-Health Implications around B...
Yakubu Hannafi, Koki F Salmanu, Musa S Abdulhamid, Ali Yakubu, Abubakar Muhammed and Aliyu Rilwan
abstract View article PDF
This study assesses the activity concentration of Radon in underground water around Bagwai
and Shanono artisan gold mining Sites in Kano State, Northwestern Nigeria. A total of (39)
underground water samples, including sixteen (16) from boreholes and twenty-three (23)
from hand-dug wells, were randomly collected. The activity concentration of Radon was
analyzed using a portable radon detector, Rad7, from DURRIDGE Company. The results
show that the radon concentration in all the water samples ranges from 4.13 to 45.24 Bq/l,
with an average value of 20.13 Bq/l. The calculated total annual effective dose due to both
ingestion and inhalation for different age groups ranges from 42.40, 57.60 and 65.30 (µSv/y)
to 457.10, 622.06 and 704.60 (µSv/y), with an average value of 203.32, 276.70 and 313.51
(µSv/y) for adults, children, and infants respectively. The total excess lifetime cancer risk for
different age groups varies from 0.00149, 0.00202 and 0.0247 to 0.0160, 0.0220 and 0.0247
with mean values of 0.00703, 0.00956 and 0.0109 for adults, children, and infants. The
obtained results are higher than the internationally recommended limits set by USEPA of 4 to
40Bq/l and the International Commission on Radiological Protection (ICRP) value of
0.1mS/y; thus, the water in the study area is not suitable for drinking and other domestic
purposes. Hence, remedial action needs to be taken by the authorities to ensure the continuous
utilization of water within the study area.
Open Access
Investigating the influence of precursor temperature on the bandgap energy, structural, and morphol...
Emmanuel O Okechukwua, Imosobomeh L Ikhioya and Azubuike J Ekpunobi
abstract View article PDF
In this study, we use electrochemical deposition on FTO to grow BaTiS thin films. By varying
the temperature of the precursors, we conducted thorough growth studies to understand how
these process parameters affected the structure of BaTiS films. The diffraction peaks in the
XRD pattern match the cubic barium sulfide structural phase. The observed peaks, 39.994 °
and 65.742 ° at 35 °C; 39.982 ° and 65.717 ° at 45 °C, and 39.995 °, 63.920 °, and 65.856 ° at
55 °C. The film deposited at 55 °C had a surface morphology with uniformly distributed
spherical-shaped particles that formed agglomerations. The film's surface was smooth,
providing a clearer look at the grain boundaries, suggesting a polycrystalline composition. The
films deposited at temperatures of 35 °C, 40 °C, 45 °C, 50 °C, and 55 °C yielded energy band
gaps of 2.98 eV, 2.90 eV, 2.69 eV, 2.68 eV, and 2.30 eV, respectively. The result showed that
the films' energy band gap decreased as the deposition temperature increased. The varied
energy bandgap of the films confirmed the effects of deposition temperature on the films.
Open Access
Electrochemically Deposited Iron Sulphide Material by Adjusting the Deposition Time for Photovoltai...
Ernest O Ojegu and Imosobomeh L Ikhioya
abstract View article PDF
An electrochemical deposition technique was employed to synthesize FeS material. The Iron
nitrate nonahydrate (Fe(NO3)2.9H2O) and sodium sulphate (NaSO4) are part of the
electrochemical bath system. The films synthesized have a polycrystalline structure with
diffraction peaks and a preferred orientation along the (111) diffraction plane. The significance
of high peaks lies in their ability to provide a spacious surface area for efficient photovoltaic
activities. By increasing the deposition time of FeS, the film thickness decreased from 108.98
to 100.87 nm. The FeS absorbance decreases as the wavelength approaches the VIS-IR region.
The FeS material had the highest absorbance value at 30 s across the entire spectrum, averaging
a maximum of 0.072 in the ultraviolet region. The films deposited had energy band gaps
ranging from 2.12 to 1.58 eV. The energy band gap also decreased as the deposition time and
film thickness decreased. The bandgap energy range found in this study is perfect for absorbing
solar energy radiation above 1.58 eV, making it ideal for solar cell absorber layers.
Open Access
The Effect of Work Function of Back Contact Metals on the Performance of CdTe Solar Cells
Mohammed M Aliyu
abstract View article PDF
The CdTe thin film solar cells suffer power losses at the back contact due to charge losses due
to poor mismatch of the work function of interfacing back contact materials. Thus, there is a
need to find appropriate back contact materials that do not reduce cell performance by creating large Schottky barriers. One of the established strategies employed to reduce the barrier height is depositing metal(s) with high work function to the CdTe back surface. In this study, we used the average of the commonly reported values of the work function of metals, to investigate the effects of various metals, when used as back contacts, on the performance of CdTe solar cells. Without any other strategy employed to overcome the Schottky contacts, the solar cells' efficiency is gravely diminished when metals with work functions lower than 5.0 eV are used. While metals like Pt, Pd, and Au with very high work functions produce cells with efficiencies of up to 18.6%, lower work functions metals like Al almost completely diminished the
efficiency to less than 0.5%. our findings indicate that the Schottky barrier affects mainly Voc and FF, as Jsc showed only a slight reduction. When subjected to extreme operating temperatures, the efficiencies largely decreased with temperature. Temperature coefficients of -0.3 to -0.45/°C have been obtained, for the highest-performing metals,
Open Access
Development of Heat Conduction Equation using a Heat Propagation Model on ERK Solar Dryer Plates...
Yayat Ruhiat and Suherman Suherman
abstract View article PDF
The heat conduction equation is a combination of first-order and second-order differential equations. Solving first-order differential equations is necessary to examine temperature as a function of time. Meanwhile, solving second-order differential equations is needed to examine temperature as a function of space. The heat flux equation is based on Fourier's law, which shows that temperature is a function of time and space. Understanding heat conduction can be improved by building a heat propagation model on the Solar ERK dryer plate. Analysis of heat
propagation on the drying plate used the Finite Difference Approach (FDA) method with
explicit and implicit schemes. With an explicit scheme, the FDA method calculates the
temperature (T) at a point on the spatial derivative term, when T is at time t, while the implicit
scheme calculates T at a point on the space derivative term when T is at time t+?t. Heat propagation at each time change was analyzed by developing a program using the MATLAB
17 application. The results of the analysis show that there are differences in heat propagation
between the explicit and implicit schemes. The convergence and stability of calculations in
explicit schemes are unstable, causing problems at the time step. Meanwhile, the implicit
scheme is carried out simultaneously on all nodes so that convergence and stability are easily maintained, and there are no time-step limitations
Open Access
Ultra-Thin 2D MoTe2 for Electron Transport Material Application in Perovskite Solar Cell: A Theoret...
Mohammed Adamu, Shuaibu Alhassan, Sadiq G Abdu and Muhammed M Aliyu
abstract View article PDF
With rapid progress in power conversion efficiencies, perovskite solar cells (PSCs) have shown great potential as next-generation low-cost, efficient solar cell devices. Ultra-thin pure and Br-doped MoTe2 monolayer materials are promising candidates for alternative electron transport material in perovskite solar cell applications. The electronic, and optical properties of these materials were calculated using projector augmented plane wave (PAW) based on popular density-functional theory (DFT). These properties were calculated using Pardew-Burke-Ernzerhof generalized gradient approximation (PBE-GGA). The band structure for the considered materials has been determined using full relativistic spin-orbital coupling (SOC). Our results indicate that pure and Br-doped 2D-MoTe2 were n-type semiconductors and had direct band gap energies of 1.01 and 1.21 eV respectively. The optical properties of the materials such as relative dielectric constant, transmission and reflectivity are presented. Using these properties, the 1-D solar cell capacitance simulator (SCAPS-1D) software was used to design solar cells based on monolayer pure and Br-doped MoTe2 as an electron transport layer (ETL). The maximum efficiencies of these cells are 13.121%, and 24.016% with VOC of 1.067 V and 1.186 V, JSC of 21.678 mA/cm2 and 25.251 mA/cm2, and FF of 56.720% and 80.139% were realized with the pure and Br-doped ETLs respectively. The performance of our solar cells is comparable to traditional Si-based solar cells. The results show how monolayer pure and Br-doped MoTe2 can serve as a suitable ETL material for perovskite solar cells.
Open Access
Landslide Susceptibility Assessment in a Basement Environment using Slope and Geoelectric Parameter...
Adeyemo I Adedotun
abstract View article PDF
The assessment of landslide susceptibility was carried out at Adebowale community in Akure
South Local Government Area of Ondo State, Nigeria. A total of (60) sixty Vertical Electrical
Sounding (VES) data were acquired using Schlumberger electrode configuration with a
maximum half-current electrode separation (AB/2) of 150 - 225 m. The Vertical Electrical
Sounding (VES) results were presented as maps and tables. The VES results delineated three
to five geoelectric layers across the study area. The A, H, K, HA, KH, AKH and HKH are the
seven sounding curve types delineated in the area. The resistivity of the topsoil, clayey sand
weathered layer, sandy clayey weathered layer and weathered bedrock/fresh bedrock varies
from 24 to 961 ?m, 13 to 4141 ?m, 24 to 72739 ?m and 122 to 100000 ?m respectively. Four
parameters of importance to landslide were used to develop a landslide susceptibility model for
the study. The parameters consisted of slope, topsoil resistivity, weathered layer resistivity, and
longitudinal resistivity. These parameters or factors were assigned weights and ratings based
on their significance to the landslide. A landslide susceptibility map (LSSM) was produced
using the determined landslide susceptibility index. The LSSM classified the area into five
landslide susceptibility zones; very low, low, moderate, high and very high respectively. The
model was able to predict areas with very low susceptibility, low susceptibility, moderate
susceptibility, high susceptibility and very high susceptibility within the study area. The
northern pocket of the southwestern part of the study area revealed very low to low landslide
susceptibility while the southwestern and north-central parts of the map are of moderate to very
high landslide susceptibility
Open Access
Structural, Electronic, and Optical Properties of Stanene and Stanene-Doped Non-metals for Optoelec...
Abdulkadir S Gidado, Lawal Abubakar, Lawan S Taura, Abdullahi Lawal and Abdulmalik Isah
abstract View article PDF
In this paper, the structural, electronic, and optical properties of sulfur and phosphorus-doped
stanene were investigated using the density functional theory (DFT) projected augmented wave
(PAW) method. Native stanene has a zero-band gap but when doped with sulfur and phosphorus
atoms, it results in a direct band gap opening. Specifically, the bands of stanene doped with
25.0% sulfur and 25.0% phosphorus are 0.77 eV and 0.47 eV compared to other doping
concentrations. Optical analysis shows anisotropic behavior in stanene-doped phosphorus
and sulfur with higher refractive indices than native stanene. This suggests that SnP12.5%,
SnP25.0%, SnS12.5% and SnS25.0% are promising for optoelectronic applications
Open Access
Assessment of Radiological Risks in Sections of Niger Delta University campus, Bayelsa State, Niger...
Peter E Biere, Lateef Bamidele, Abayomi E Ajetunmobi and Kugbere Emumejaye
abstract View article PDF
This paper presents an assessment of background radiation levels within the Niger Delta University campus, Bayelsa State Nigeria. A portable Geiger-Muller tube (Radiation Alert) was used to detect the background ionizing radiation within a temperature range of -100 ? to 500 ?. Results of absorbed dose rate in air in the main campus, open field and new campus vary from 104.4 nGy/h to 278.4 nGy/h with an average of 156.6 nGy/h, 34.8 nGy/h to 174.0 nGy/h with an average of 95.7 nGy/h and 69.6 nGy/h to 174.0 nGy/h with an average of 113.1 nGy/h respectively. The annual effective dose estimates ranged from 0.160 mSv/y to 0.427 mSv/y with an average of 0.024 mSv/y, 0.053 to 0.267 mSv/y with an average of 0.147 mSv/y and 0.107 to 0.267 mSv/y with a mean of 0.173 mSv/y in the main campus, open field and new campus respectively. The excess lifetime cancer risks ranged from 0.442 to 01.174 x 10-3 with a mean of 0.663 x 10-3, 0.146 to 0.736 x 10-3 with an average of 0.405 x 10-3 and 0.295 to 0.736 x 10-3 with average 0.479 x 10-3 in main campus, open field and new campus respectively. The estimated averages of absorbed dose rates in the air within Niger Delta University were above the world average of 57 nGy/h. Annual Effective Dose Equivalent (AEDE) are below the safe limit of 1 mSv/y for humans. The results of this study provide baseline information on the background ionizing radiation and can be referenced for future works in the area.
Open Access
Integration of Geologic and Geoelectrically Derived Parameters for Aquifer Vulnerability Assessment...
Adeyemo I Adedotun, Boluwade B Stella, Sanusi S Olumide and Akande V Oluwatimilehin
abstract View article PDF
Assessment of aquifer vulnerability was carried out in the northwestern part of Akure,
Southwestern Nigeria where the presence of automobile workshops is the major source of
pollution using integrated methods of multi-criteria approach and physico-chemical
investigations. 187 vertical electrical sounding (VES) data were acquired using the
Schlumberger array technique with (AB/2) ranging from 65 - 150 m. Six geologic and
geoelectric parameters; surface elevation, lithology, aquifer overlying layer resistivity, aquifer
overlying layer thickness, coefficient of anisotropy and hydraulic conductivity were combined
to develop an aquifer vulnerability model (AVM) for the study area using the GIS technique.
These factors were subjected to the Fuzzy Analytical Hierarchy Process (FAHP) method of
weightage determination to assign weights to each criterion of the aquifer vulnerability
conditioning factors (AVCFS) using GIS. The AVM shows that the eastern and western flanks
of the study area are of moderate to high vulnerability, while the central area is mainly of very
low to moderate vulnerability. Fifteen (15) water samples were obtained from wells across the
area for physico-chemical analyses. The predicting accuracy of the aquifer vulnerability model
was validated using one of the physiochemical parameters determined from water samples
collected across the area (lead) and longitudinal conductance. The validations from the two
approaches produced an accuracy of 73% and 74% respectively which proved the reliability of
the model. The produced aquifer vulnerability map can be used for precise decision-making
processes in environmental planning and groundwater management in the study area.
Open Access
Comparative Studies of Subsurface Layers’ Competence Evaluation using TOPSIS and AHP Models at Il...
Adeyemo I Adedotun, Akande V Oluwatimilehin, Akinlalu A Adewale and Sanusi S Olumide
abstract View article PDF
The incessant collapse of buildings associated with geotechnical incompetence in different parts of Nigeria and the rapid growth of Ilaramokin town near Akure Southwestern Nigeria motivated this work. Two multi-criteria decision analysis approaches were used in integrating geoelectric parameters (topsoil resistivity, weathered layer resistivity and bedrock resistivity), static water level measurements and geology in evaluating the subsurface geotechnical competence of Ilaramokin. Thirty (30) vertical electrical sounding, eighty-six (86) static water level measurements and geological maps were used. The vertical electrical sounding (VES) results delineated three to five geoelectric layers which correspond to four geologic layers namely; the topsoil, weathered layer, partially weathered/fractured basement and presumed bedrock. The resistivity of the geologic layers varies respectively from 48 - 701, 31 - 1065, 14 - 139, 132 - 6582 Ωm, while their thickness varies from 0.4 - 4.1, 1.3 - 11.6 and 4.0 - 20.1 m in the three upper layers respectively. The VES results were presented as topsoil, weathered layer and bedrock resistivity maps. The VES results, static water level measurement and geology were integrated using both the Technique for the Order of Prioritization by Similarity to Ideal Solution (TOPSIS) and Analytic Hierarchy Process (AHP) models to produce geotechnical competence maps. Consistency test and grain size analysis were carried out on 10 soil samples obtained across the area to validate the geotechnical competence model maps produced using both TOPSIS and AHP models. The validation showed that the geotechnical model map produced from the TOPSIS model has a higher percentage (90%) of correlation with consistency tests and grain size analysis compared to that of the AHP model (70%).
Open Access
Effect of Filler Content and Particle Sizes on the Mechanical and End-Use Properties of Eggshell Po...
Ishaya Iliyasu, Hussaini Yahaya, Mbaka Stephen and Mohammed Abubakar
abstract View article PDF
In pursuit of environmental sustainability, polymers filled with bio-particulates are replacing
traditional plastic components. Epoxy Polymer composites of eggshell powder were prepared
at filler contents of 10 wt%, 20 wt%, 30 wt%. the particle size of the eggshell powder was 75
μm, 180 μm, and 250 μm. The composite samples were prepared using the Carver Inc.
Hydraulic Press (3851-0) by compression molding and the resulting composites were produced in sheets. Some mechanical properties of the composite were determined. the result showed that the eggshell powder improved the tensile modulus, flexural strength and impact strength of the polymer these properties increased with increase in the filler content and decrease in the
filler size. But at 30 wt% a decrease in these properties were observed which can be attributed
to agglomeration and stress concentration effects. Highlighting the fact that the dispersion and distribution of filler particles within the matrix play a crucial role in determining the mechanical properties. Inhomogeneities in mixing or particle clustering could lead to variations in the measured properties.
Open Access
Bound State Solutions and Energy Spectrum of the Schrödinger Equation for Core-Shell Polystyrene/S...
Imrana M Habibat, Patrick O Akusu, Jibrin A Yabagi, Baba Alfa, Ndanusa Babakatcha, Muhammad B Ladan
abstract View article PDF
In this paper, the Born-Mayer potential is used to describe the core-shell polystyrene nanoparticle and the Schrodinger equation for this nanoparticle is solved rigorously using the Nikiforov-Uvarov (NU) method to obtain the exact bound state solutions and energy spectrum. This is achieved by inserting the Born-Mayer potential into the Time Independent Schrödinger Equation (TISE), obtaining the radial part and solving, exactly, for the expectation values of the energy spectrum and the corresponding eigenfunctions applying the Nikiforov Uvarov (NU) method. The eigenvalue expression obtained is similar to earlier work on Soliton solution in nonlinear lattice with the nearest neighbor Born-Mayer interaction.
Open Access
Assessment of Natural Radioactivity Concentration in Soils from Irrigation Farming Areas within Kud...
Hayatu Umar, Gazara A Bala, Yusuf Ayuba and Mustapha Shafiu
abstract View article PDF
The activity concentrations of natural radionuclides 238U, 232Th and 40K in soil samples from Kudan Local Government Area irrigation farming areas have been evaluated using gamma-ray
spectrometry. The results of the activity concentrations of 238U, 232Th and 40K range between
18.15 to 34.66 Bq/kg, 16.01 to 18.83 Bq/kg and 205.51 to 461.25 Bq/kg respectively. The
activity concentration of 40K was seen to be higher than the world average value of 370 Bq/kg
at Kauran Wali South (GO3K) 375.25 Bq/kg, Doka (GB1K) 389.60 Bq/kg, Kauran Wali North
(GB2K) 420.15 Bq/kg, Likoro (GB4K) 383.65 Bq/kg, Garu (GB5K) 461.25 Bq/kg, Zabi
(GB6K) 372.76 Bq/kg and Kudan (GB7K) 382.50 Bq/kg. The activity concentrations of 238U
and 232Th were observed to be high at Garu (GB5K), with values of 34.66 and 18.83 Bq/kg
respectively, however, these values were still below the world average value of 40 Bq/kg as
reported by the United Nations Scientific Committee on the Effects of Atomic Radiation
(UNSEAR) in 2000. The average values for the indoor absorbed dose rate (Din), Internal
Hazard Index (Hin), External Hazard Index (Hex) and Indoor Annual Effective Dose (ADE)
were evaluated to be 83.07 nGy/hr, 0.35, 0.28 and 0.41 mSv respectively. The estimated
radiological indices were seen to fall within the internationally acceptable limits except for the
indoor absorbed dose rate (Din) whose values were all higher than the acceptable limit of 60
nGy/hr as recommended by UNSCEAR in 2000. The high values obtained from this study
could be attributed to the excessive use of fertilizers by the farmers within the study area.
Open Access
Geoelectrical Investigation of Groundwater Potential in University of Abuja, Main Campus
Temitope R Tijani, Abu Mallam and Abel U Osagie
abstract View article PDF
Electrical resistivity techniques of geophysical prospecting have been used to evaluate the
groundwater potential of the University of Abuja Health Services Centre at the main campus.
This research aims to identify suitable locations for productive wells and boreholes, determine
the depth of the bedrock, as well as measure resistivity and overburden thickness. The survey
employed Vertical Electrical Sounding (VES) along five profiles, comprising fifty (50) VES
stations covering the survey area. The resistivity data obtained are analysed using IPI2win
software. The analysis of the resistivity data revealed that the survey area can be divided into
four geoelectric layers: topsoil, clayey sand, weathered layer, and fresh basement. The
resistivity values of these layers range from 38.7-1427 Ωm, 16.2-310 Ωm, 32.1-1714 Ωm and
1007-9528 Ωm respectively. The fresh basement layer was found to have an infinite thickness.
Significantly, potential regions with low resistivity values indicating the presence of
groundwater were identified at a depth of 18.3 m. Furthermore, the average overburden
thickness in the study area was 35 m while the longitudinal conductance of the overburden
ranges from 0.04 – 1.87 mho. Results obtained indicate the main aquifer in the area consists of
a thick weathered layer of overburden and a weathered basement with relatively low resistivity,
suggesting a potentially productive groundwater yield. This information is crucial for future
planning and decision-making regarding the siting of wells and boreholes and the sustainable
utilisation of groundwater resources in the University of Abuja main campus.
Open Access
Analysis of the Occurrence of the First Most Intense Geomagnetic Storm (G4) to Hit the Earth in Sol...
Hammed A Lawal and Mukhtar I Muhammed
abstract View article PDF
A study of the occurrence of the first intense Geomagnetic storm (G4) to hit the Earth since the start of the Solar Cycle 25 is carried out. This study analyzed the Geomagnetic Storm that occurred between the 28th of October and the 7th of November 2021. The values of the Disturbance storm time (Dst) index of the storm reach -115 nT (G4) which occurred on the 4th of November at 1300UT. The storm is the first intense magnetic storm that occurred in the solar cycle 25. It is also a multiple-step storm with moderate two-step storm occurrence which occurred on the 5th and 6th of November at 1500UT and 0600UT respectively towards the recovery phase after the intense storm. The interplanetary magnetic field (IMF)Bz (nT) during these storm events decreases. Our analysis shows that the rise in solar wind speed, temperature and the enhancement of pressure plays a significant role in the occurrence of the first intense Geomagnetic storm of Solar Cycle 25.
Open Access
Electrical resistivity measurements in delineating near-surface lithologic units in Federal College...
Esiekpe L Ese, Imiere E Edeki, Alade M Aiyeoribe and Nuhu A Tafida
abstract View article PDF
An electrical resistivity investigation was carried out in parts of the College of Education
(Technical) Asaba to delineate the subsurface lithologic units with special emphasis on the competence and suitability for engineering foundations. A total of ten (10) vertical electrical
sounding and two (2) horizontal profiling stations were covered within the study area using the
Schlumberger and dipole-dipole configurations. The acquired data was analyzed using WinResist and RES2DINV Software; the subsurface within the study area is composed of mostly 3 geoelectric layers: topsoil, clay/sandy clay/clayey sand and sand. The second and third
layers have relatively low resistivity ranging between 29 – 94 Ωm and consist of incompetent clayey material underlying about 60 % of the investigated study area. The interpreted field results showed a significant clay overburden that is over 5 m thick. A fourth layer of sand with resistivity values ranging between 451 – 1258 Ωm was encountered at depths between 4.9 – 11.5 m; the thickness of this layer with reference from the borehole log is greater than 20 m. It is therefore recommended that the incompetent clayey material be avoided or excavated before
constructing any structure.
Open Access
Assessment of Selected Metals in Onion Bulbs and Leaves Collected from Samaru Market, Zaria, Kaduna...
Onoja D Emmanuel, Itodo D Adukwu, Ejila A Odeh and Adejo E Ogweye
abstract View article PDF
This study examined the levels of metals (Mg, Al, Si, P, S, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Zr, Nb, Mo, Ag, Sn, Sb, Ta, Pt, Au, Pb, and Bi) in onion bulbs and leaves in light of the latent toxicity, unsolvable character, and snowballing behaviour of heavy metals. The onion bulbs and leaves were randomly selected from the Samaru market chopped, dried, and ground
into a powder for X-Ray Fluorescence Spectrometer (XRF) measurement. Except for
concentrations of Si, Ti, Zr, and Ag, with the value of 9.996, 4.051, 2.047 and 2.082 mg/kg in
the onion bulbs and 20.23, 5.861, 1.175 and 1.538 mg/kg in the onion leaves respectively,
which were higher than the permissible level of 0.800, 0.530, 0.000005 and 0.014 respectively,
all the metals analysed were at or below the World Health Organization's (WHO) permissible
limit. The findings generally indicated that Si, Ti, Zr, and Ag poisoning could result from eating onion bulbs and leaves from the Samaru market due to the Si, Ti, Zr, and Ag health risks. To avoid metal poisoning and subsequent bioaccumulation of the metal in the systems of
consumers and the ecosystem at large, there is a need for a quarterly examination of the metal content in the onion bulb and onion leaf in the Samaru market.
Open Access
Exploring the Physical Properties of Tungsten Diselenide (WSe2): A First Principle Approach...
Mohammed Adamu, Shuaibu Alhassan, Sadiq G Abdu and Muhammed M Aliyu
abstract View article PDF
The physical properties of crystalline compounds are highly essential for predicting their
applications in various nanodevices. Density functional theory is very useful in that regard.
Herein, some physical properties such as structural stability, and electronic, optical and
mechanical properties of two-phase bulk WSe2 have been comparatively investigated by first
principle calculations. Band structure calculations elucidate that the materials are indirect band
gap semiconductors having band gap energy in the range 1-1.5 eV. It was observed that the
hexagonal crystal has higher absorption coefficients compared to the trigonal phase. Analysis
of elastic constants of the materials carried out using the Born criteria method indicates that all
systems are mechanically stable at room temperature. Our findings are in close agreement with
the previous experimental and theoretical results, this further suggests that the materials are
promising in optoelectronics applications.
Open Access
Investigation of Leachate Plume and Groundwater Pollution using Geophysical and Physio-chemical Met...
Agu C Rita and Abu Mallam
abstract View article PDF
A geophysical study has been carried out using the electrical resistivity method, Very LowFrequency Electromagnetic (VLF-EM) and physiochemical analysis to investigate the effects
of groundwater contamination in the vicinity of an open dumpsite at Idugosa. A Vertical
Electrical sounding was carried out at 100 m away from the dumpsite and the results revealed
an H-type curve with 3- layers, with a low resistivity value of 90.0 Ωm, thickness of 9.8 m and
depth of 11.3 m at the weathered basement. The control VES revealed 5 –layers of HK-type
curve. The resistivity of the weathered and fractured basement ranged from 241.8 Ωm to 2908.4
Ωm with a thickness range of 3.5 m to 13.6 m and a depth range of 5.6 m to 19.1 m. Results
of the horizontal profiling using Wenner profiling revealed a low resistivity value of 1.6 Ωm to
3.8 Ωm at a depth of 15 m to 30 m, concentrated at stations 20 to 100. The bottom of the western
part showed that the leachate plume had infiltrated and contaminated the groundwater in the
zone. The VLF-EM with the three profiles revealed high current density values on the KarousHjelt filter plot at distances of 20 m to 38 m for profile 1, 25 m to 50 m and 75 m to 95 m for
profile 2, revealing the presence of contaminants which is mainly from decayed organic matter
from waste bodies and heavy metals from the dumpsite. Profile 3 which is further away from
profile 1 revealed that the contamination is reduced as we move further away from the dumpsite
at about 10 m to 20 m, 50 m to 60 m and 90 m respectively. The physio-chemical analysis
results showed a pH range of 6.73 – 7.17 which is within the World Health Organization
(WHO) standard (6.5 - 8.5). The Electrical Conductivity (EC) value of the Idugosa dumpsite
was found to be 804.9 μS/cm, which is above the WHO standard for EC values, which should
not exceed 400 μS/cm. This high value can be attributed to the infiltration of the leachate plume
from the dumpsite. The EC for Idugosa control which is 188.0 μS/cm is within the WHO limit
for groundwater, thus its safe for consumption.
Open Access
Assessment of Heavy Metals in Fish Tissues of Tilapia and Catfish from River Hadejia, Northern Nige...
Lawan M Yalwa, Sani G Durumin Iya and Haruna Ahmad
abstract View article PDF
Kidney failure has become a growing problem at Hadejia Emirates over the last decade. This can be attributed to water pollution, possibly due to heavy metal contamination of River Hadejia that affects organisms living in it, such as fish. This study is aimed to determine the
concentration of heavy metals (As, Cd, Cr, Pb) in two fish muscles. The research was conducted on tilapia and catfish where two samples of both fishes were used. The fish tissues were cut and oven-dried at 110 °C, and then a motor and pestle were used to powder the dried fish
sample. A wet digestion method was used based on the analytical methods for Atomic
Absorption Spectrometry (AAS). The result obtained shows that the concentrations of heavy
metals (Cr, Cd, As and Pb) in both fishes were found to be 0.3220 ± 0.0028; 0.1656 ± 0.002
(ð‘šð‘”/ð‘˜ð‘”), 0.0319 ± 0.0018; 0.0333 ± 0.0018 (ð‘€ð‘”/ð‘˜ð‘”), 0.0697 ± 0.0011; 0.1035 ± 0.0015
(ð‘šð‘”/ð‘˜ð‘”) and 1.008 ± 0.0035; 0.600 ± 0.002 (ð‘šð‘”/ð‘˜ð‘”) respectively. The mean concentration value of the two samples of both tilapia and catfish were found to be above WHO standard limit except for cadmium in tilapia which is below WHO standard limit.
Open Access
Influence of Rare Earth Ions (REIs) on the Visible Emission of Magnesium Sodium Borate Glasses...
Garba M Ephraim, Emmanuel A Soje, Charles S Bature and Solomon D Kwasu
abstract View article PDF
Borate glass systems have been extensively studied for practical applications in optical display
devices by virtue of their peculiar luminescence efficiency. However, the attainment of high
emission from borate glass materials via apposite control of rare earth ions (REIs) contents
remains a topical issue in Material Physics. In this paper, we report the influence
of REIs (Dy3+, Eu3+, and Sm3+) on multiple-colour emission of magnesium sodium borate
(MSB) glasses fabricated by using the conventional melt-quenching method. These glasses were optically characterized via X-ray Diffraction (XRD), UV-VIS-NIR and
Photoluminescence techniques. The XRD pattern confirms the amorphous nature of the as-prepared glasses. The absorption spectra disclosed several absorption bands at 347 nm (6H15/2 → 6P7/2) for Dy3+, 393 nm (7F0 → 5L6) for Eu3+ and 403 nm (6H5/2 →6P5/2) assigned for Sm3+ respectively. Also, the emission spectra radiate at 463 nm (4F9/2 → 6F11/2 + 6H9/2), 612 nm (5D0 → 7FJ) and 599 nm (4G5/2 → 6H7/2) for Dy3+, Eu3+, and Sm3+ correspondingly, wherein Dy3+ emits blue, yellow, and red light, Eu3+ emits red light and Sm3+ emits reddish-orange light. Finally, 1.0 mol% content of Dy3+, Eu3+, and Sm3+ in MSB glasses was found to be optimal and hence considered the best optical host for colour display devices.
Open Access
Dielectric Application of Agro-waste Reinforced Polymer Composites: A Review
Ishaya Iliyasu, Hussaini Yahaya and Mbaka Stephen
abstract View article PDF
Proper disposal of agricultural waste and polymers after use has long been one of the toughest
environmental problems. Since it solves the majority of environmental issues, this has resulted
in the development of commercial materials made from biodegradable and renewable sources,
a focus of research around the globe. To make composites that are recyclable and degradable,
natural fibres have been developed as reinforcing materials. Composite technology is a
successful method to enhance the performance of insulating materials used in power system
applications as part of the endeavour to optimize materials for industrial applications. The trend
in the development of dielectric materials from agricultural waste (agro-waste) reinforced
polymeric composites for use in electrical and electronic power systems is the main focus of
this study. This article's objective is to provide a brief overview of the many kinds, best
practices, and most often used biodegradable polymer matrix reinforcements in eco-composites
for dielectric applications. Dielectric constants, dielectric loss factor, volume resistivity, and
other properties of composites made with agro-waste as filler, at various frequencies and filler
contents, with and without chemical modifications, have been discussed, as well as their
prevails and prospects for the future.
Open Access
Determination of Heavy Metals in Water Samples within the Southern Part of Kaduna State, Nigeria...
Mathew Samaila, Kure Nicodemus, Daniel H Isaac and Gyuk P Musa
abstract View article PDF
This paper investigated the presence of heavy metals in water samples from three selected sites in the southern part of Kaduna State, Nigeria. Twelve (12) samples were analysed at the Federal Ministry of Agriculture and Rural Development, Kaduna using Atomic Absorption Spectrophotometer (AAS). Levels of some heavy metals, Zn, Cu, Mn, Fe, Ni, Cr, Cd, Pb, Ca, Mg, Na and K were determined in water samples collected from the research area. The results
obtained show that, the recorded mean values of Zn, Cu, Mn, Cd and Mg were within the WHO/GDWQ guidelines; while Na and Ca recorded mean values below the World Health
Organisation (WHO)/Guidelines for Drinking- Water Quality (GDWQ) minimum mean value,
Ni, Fe, Cr and Pb were found to be considerably high in the water samples, which exceeded the
WHO/GDWQ maximum mean value. Therefore, the result shows the presence of heavy
elements in the sampled area. The low mean values of Ca and Na within the sampled area could
lead to poor bone formation risk like rickets among the populace. While consumption of such
vital elemental nutrients is recommended, it is however advised that the populace should avoid consumption of Ni, Fe, Cr and Pb in high content above the stipulated WHO/GDWQ
guidelines.
Open Access
First principle study on the Structural and Electronic Properties of Lead-Free Double Halide Perovs...
Ahmad Zainab, Magaji Ismail, Alhassan Shuaibu and Bashiru K Sodipo
abstract View article PDF
The structural and electronic characteristics of Cs2InSbCl6 were investigated using first
principle density functional theory (DFT) within local density approximation (LDA) and
generalized gradient approximation (GGA) as implemented in the Quantum ESPRESSO
package. A supercell with 40 atoms was used in carrying out the calculations, using the
optimized lattice parameters of the Cs2InSbCl6 (a = b = c =11.342 Ǻ). The findings revealed
that Cs2InSbCl6 is a direct band gap material with gaps of 0.74 eV and 0.99 eV for LDA/PZ
and GGA/PBE respectively, in which the GGA/PBE gap shows consistency within the
literature range. The calculated densities of states highlight the contributions of the constituent
atoms within the valence and the conduction bands.
Open Access
First-principles Study on the Structural, Electronic, and Elastic Properties of Transition Metal Di...
Shehu A Yamusa, Amiruddin Shaari, Ibrahim Isah, Basima Farzan, Magaji Ismail, Summanuwa T Ahams and
abstract View article PDF
In this paper, the structural, electronic, and elastic properties of molybdenum disulfide (MoS2)
in hexagonal and trigonal phases were investigated using first-principles calculations based on
density functional theory (DFT) as implemented in the Quantum ESPRESSO package. Our
findings from the structural and electronic properties of MoS2 show that bulk hexagonal and
trigonal MoS2 phases have a calculated bandgap of 1.37 and 1.56 eV respectively, which is in
good agreement with available theoretical and experimental results. The elastic properties show that both space groups of MoS2 are brittle at zero pressure and they also agree with Born's
mechanical stability condition. The overall results place our new optimized MoS2 as a potential
candidate for optoelectronic application.
Open Access
In-Phase/Quadrature Signatures of a Very LowFrequency Electromagnetic Survey for the Delineation of...
Micah Adamu, Nasir K Abdullahi and Matoh D Dogara
abstract View article PDF
The VLF-EM geophysical technique was used to delineate the zones of cassiterite at Rafin
Bareda, Dutsen-Wai, Kubau Local Government area of Kaduna State, Nigeria which is located
at Latitudes 10°51'46''N and Longitudes18°12'50''E. The research covered eleven profiles taken
uniformly in the West-East direction each of length 1000 m with a total of 1100 stations.
Scentrix VLF equipment was used to obtain the VLF-EM data (In-phase and Quadrature in
percentages) with a detected field of 19.1 kHz transmitter in Rosnay, France. The plots of inphase and Quadrature revealed various cross-overs (fractures/mineralized zones). However, the
Fraser filter of the in-phase components was employed to reduce noise and enhance signal
strength. Consequently, the Fraser-filtered of in-phase plots peaks around the crossover which
confirmed the probable fractured/mineralized cassiterite zones. The Fraser filtered of the inphase components revealed the continuous and extending nature of probable mineralized
cassiterite zones which are dominant on profiles G and H.
Open Access
Effects of Fractures on Buildings and Road Construction: A Case Study of Area BZ, Ahmadu Bello Univ...
Inalegwu A Ngbede, Onum S Adikwu, Matthew I Amanyi, Adukwu G Obinna and Cyril G Afuwai
abstract View article PDF
Structural collapse due to the absence of geophysical information has become a major concern
in the construction and building industries today. In this research, we reported the effect of
fracture on some selected buildings in Area BZ, Ahmadu Bello University, Zaria. Reflex W
software was used to analyze the vertical and horizontal profiles of the subsurface features in
two-dimensional (2D) tomography of seismically related regions. The data were collected using
MK6 Terraloc seismograph. Seismic refraction method was used to obtain relevant information
about the subsurface strata. The velocities of different layers were obtained from the distancetime graph to generate the tomography of the four profiles of 115 m distance each. Results
revealed that there are fractures beneath the surface, starting from the depth of 10 m into the
basement region as evident in the four (4) profiles with variations in the seismic velocities of
1652 to 2086 m/s and 2521 to 2955 m/s for given strata. The 2D tomography of the study area
also revealed that the eastern parts of profiles 1-3 may not be safe for the erection of buildings
and other structures without excavation, while profile 4 revealed high levels of structural
deformation and it is recommended as a high-risk region that will not support engineering
structure. We, however, recommend that further geophysical surveys should be carried out in
the area, using Electrical Resistivity Tomography (ERT).
Open Access
Stitched Transmission Line for Broadband Operations
Isaac H Daniel, Kure Nicodemus, Peter Anthony and Gyuk P Musa
abstract View article PDF
Wearable stitched transmission lines made from stripped RG174 and textile materials are introduced for broadband operations. The stitched transmission lines which are 150 mm long consists of an inner conductor surrounded by a tubular insulating layer. For shielding purposes, the structures are stitched into a denim material with conductive threads. The performances of
the stitched transmission lines with three different stitch patterns, Double Overlock, Flatlock stitch and Ric-Rac stitch were investigated and results obtained confirm that Ric-Rac stitched transmission line has fewer DC losses than the three stitched transmission lines for frequencies up to 1 ðºð»ð‘§. However, beyond that up to 2.4 ðºð»ð‘§ and above, it was observed that the Flatlock stitched transmission line and the Double Overlock stitched transmission line have fewer radiation losses compared to the Ric-Rac stitched transmission line. Similarly, the performance of the stitched transmission line when bent through curved angles of 90° and 180° was considered, and a much better S21 was observed with a curved angle of 180° for frequencies below 2.1 ðºð»ð‘§, with radiation loss increasing afterwards. Finally, the sensitivity of the design to manufacturing tolerances, with changes in cross-sectional dimensions of the stitched transmission line and the transmission characteristics with different textile substrates were both considered. While simulated results showed that the stitched transmission line is sensitive to
small variations in its circular dimensions, measured results conversely showed that Denim and Felt materials can be used as a substrate without any significant effect on its propagation characteristics.
Open Access
Design of an Automated Admission Ranking Information System (AARISYS)
Yamusa J Samuel and Mustapha Rabi
abstract View article PDF
A Decision Support System (DSS) is a useful information systems tool that supports decision-making as it aids institutional admission committees in effective and efficient decision-making. Several types of admission DSS are said to have existed over time. However, for
most of the admission DSS as seen from the literature reviewed, soft copies of data are
obtained from a source and uploaded onto the system, whereas, the DSS can be made to
obtain data directly from the source into itself, thereby speeding up system procedures. The objectives of this study, are to develop an Application Programming Interface (API) and use mathematical methods of weighted grade points for ranking and provision of information for
sensitive admission analysis and decision-making. The method of inquiry used in this study
was inductive, geared majorly towards consultations of research papers, relevant materials such as educational journals, publications, websites etc., and resource persons through oral interviews. This study adopts a qualitative approach, by studying admission DSS with the aim of improving the existing systems. A Use-case scenario was used as a design model and the
system architectural model and program flow were demonstrated as well. Thus, the DSS
developed in this study referred to as AARISYS (Automated Admission Ranking System),
was implemented using scripting (PHP & JavaScript) and markup languages (HTML & CSS)
with MySQL. The web-based system fetches Applicants' data from an external Database
(source) via an API, store and assign rank scores. Validation and defect tests were also used
and the system results were displayed. Thus, with the aid of API, admission DSS can now
obtain data from sources by itself, in contrast to the methods of inputting soft copied data, as
used by other DSS.
Open Access
Structural and Electronic Properties of Cu2+ Doped LiMn2O4 Cathode Material for Rechargeable Lithiu...
Owolabi J Adeyemi, Muhammad Y Onimisi, Victor A Odoh, Hassan G Muhammad and Mohammad L Madugu
abstract View article PDF
Spinel LiMn2O4 offers a potentially attractive alternative to the commercialized LiCoO2
because of its low cost, non-toxicity, good rate performance and superior safety, but
experiences severe capacity fading as a result of Jahn-Teller cubic phase transition to unstable
tetragonal phase especially when operated at elevated temperature (>55oC). Among the various
techniques carried out to overcome these setbacks is doping with cations to raise the oxidation
state of Mn thereby decreasing the amount of unstable Mn3+. This study focuses on the
investigation of the structural and electronic properties of Cu2+ doped LiMn2O4 using ab-initio
computational method. The structural properties of both un-doped LiMn2O4 and Cu2+ doped
LiMn2O4 were collectively obtained using both generalized gradient approximation (GGA)
employing pseudo-potentials, plane wave basis sets and XcryDen. From the electronic
properties of undoped LiMn2O4, it was revealed that in LiMn2O4, only Mn3+ ions contribute to
conduction, even though Mn3+ ions and Mn4+ ions exist together. Increasing the number of
Mn3+ brings it a unique challenge of instability. Due to this instability, avoiding the Mn3+ state
of manganese prevents Jahn-teller distortion, resulting in a reduced phase transition. Based on
the results from the first-principles calculation of Cu2+ doped LiMn2O4, the Cu valence in doped
spinel LiCu0.25Mn0.75O4 is Cu2+ at a fully lithiated state. When half of the Li ions are extracted,
the Cu2+ ions oxidized to Cu3+ ions. Since Cu2+ is a di-valent element, the dopant act as
electrochemically active centres for valence change, leaving two trivalent ions to only take on
+4 oxidation states stably, thus increasing Mn-O bonding strength which ultimately suppressed
Jahn-Teller distortions. However, previous studies show that Cu2+ substitution shrinks the
lattice because the ionic radius of Cu2+ is smaller than that of the host Mn3+ ions, thereby the
reversible capacity of Cu-doped spinel may be reduced as Cu ions can only provide one electron
per ion.
Open Access
Effect of Single Atom Doping on Structural, Electronic and Magnetic Properties of Hexagonal Silicon...
Yakubu A Tanko, Oyedare T Maha, Alhassan Shuaibu and Peter Olusola
abstract View article PDF
In this paper, the structural geometry, electronic and magnetic properties of single magnesium
(Mg) and vanadium (V) atoms doped 4H-SiC system were investigated. For the structural
geometry of each sample, the energy substitution, as well as bond length, were calculated;
results obtained indicate that the bond length of Silicon-Magnesium (Si-Mg) and SiliconVanadium (Si-V) was 1.90 Ã… and 2.02 Ã… respectively, greater than that of silicon-carbon (SiC) 1.89 Ã… in pure SiC. This result indicates that the bond length increases due to the
introduction of dopants with greater radii than that of Si. It also shows that both Mg and V
doping changes the structure from non-magnetic ordering to magnetic in nature. The band
structure result for both undoped and doped shows the presence of valence band maximum
(VBM) and conduction band minimum (CBM) around different symmetry points which
indicate an indirect band gap nature. The calculated band gap of pure 4H SiC is found to be ~
2.21 eV, which is at a wide band gap material range, but with the introduction of Mg and V
dopants, the band gap reduced significantly to ~0.4 eV and ~0.45 eV respectively. The
density of state (DOS) and projected density of state (PDOS) show the contributions of the
various states in both the VBM and CBM; after doping the Fermi energy is shifted towards
higher energy and enters into the conduction band, exhibiting spin polarization. Both DOS
and PDOS indicated that the magnetic moments mainly come from the 2p orbitals of Si atoms
and 3p for Mg dopant and 3d orbitals for V dopant. The magnetic moment for 4H-SiC/Mg
and 4H-SiC/V was calculated to be 2.23 μB and 3.24 μB.
Open Access
Measurement of Gross Alpha and Beta Activity Concentrations in Drinking Water from Sabon Gari Local...
Usman Adamu, Nuraddeen N Garba, Jibril Musa and Daniel J Adeyemo
abstract View article PDF
The gross alpha and beta activity concentrations of eighteen water samples, consisting of
boreholes and Hand dug wells from Sabon Gari Local government area of Kaduna StateNigeria have been analyzed using, the potable single channel gas free MPC-2000B-DP
detector. The results show that alpha and beta activity concentrations range from 0.96 × 10^-2 Bq/L to 47.00 ×10^-2 Bq/L and from 0.309 × 10^-2 Bq/L to 310.40 × 10^-2 Bq/L, for gross alpha and gross beta respectively. It is observed that in the overall samples, the gross alpha activity concentrations were below the 0.5 Bq/L maximum allowable limits for drinking water as recommended by World Health Organization (WHO). However, for the gross beta activity concentration, eleven (11) percent of the samples, have their activity concentrations greater
than the 1.0 Bq/L maximum allowable limits for drinking water as recommended by the WHO. This high beta activity concentration in these areas might be due to the waste
generated from industries and hospitals or as a result of the nature of farming activities
occurring in the areas. Largely, results obtained are seen to be in agreement with reports from
other authors within and outside Nigeria.
Open Access
Determination of shielding Effectiveness of Concretes with different Aggregate and cement compositi...
Anas M Salisu, Joseph I Abaleni and Abdullahi S Aisha
abstract View article PDF
The shielding effectiveness of concretes with different aggregate and cement composition was determine by shielding Co-60 gamma radiation source at center for energy research and training (CERT), Ahmadu Bello University Zaria with block concretes that contain aggregate 5.00 mm, 10.00 mm and 15.00 mm respectively. A concrete with thickness of 0.0762 m with dimension of 0.30 m x 0.30 m was formed from each of the aggregates with equal volume of sharp sand and cement. The result revealed the calculated mean free path (MFP) with values within a range of (0.033 to 0.070) m for samples DG (Dangote) and BU (BUA), mass attenuation coefficient (MAC) and half value layer (HVL) values within a range of (1.9 to 2.75) x 10-3 m2/kg and
(0.023 to 0.049) m respectively. This shows that samples DG1, DG2 and DG3 have better
shielding ability due to its lower MAC, MFP and HVL compared to samples BU1, BU2 and
BU3.
Open Access
Effect of sputtered silver thin film thickness towards morphological and optical properties of blac...
Auwal Abdulkadir, Aliyu K Isiyaku, Mustapha Isah, Dallatu U Abbas and Tijjani Ismaila
abstract View article PDF
Effect of sputtered silver (Ag) thin film thickness towards morphological and optical properties of black silicon (b-Si) fabricated by two-step silver-assisted wet chemical etching for solar cells applications is investigated. The method involves low temperature annealing of crystalline
silicon (c-Si) coated with Ag thin films of 10 nm, 15 nm, and 25 nm. This is followed by an
etching in a solution of HF:H2O2:DI H2O (1:5:10 volume ratio) at room temperature for 70 s. Dense and spherical Ag NPs with an average diameter of 203 ± 17.8 nm and surface coverage
of about 72.5% are achieved on a sample with Ag film thickness of 15 nm prior to the annealing
process. After the etching, the average nanopores’ height of ~420 nm with an average diameter of ~200 nm owing to denser Ag NPs on the c-Si surface before the etching are obtained. Optical absorption enhancement due to low weight average reflection (WAR) within wavelength region of 300–1100 nm is observed on the b-Si wafers. Sample with 15 nm of Ag thin film prior to annealing, demonstrates WAR of 7.7% compared 40.0% of the reference planar c-Si. The low WAR is due to the efficient light coupling effect of the b-Si nanopores. The fabricated b-Si nanopores can be used in b-Si solar cells for enhanced optical absorption and high photocurrent in the future.
Open Access
Investigation of Groundwater Potential Using Electromagnetic Method at a Basement Complex Area of U...
Onoka Adokiye and Mallam Abu
abstract View article PDF
The Very Low Frequency Electromagnetic Method (VLF-EM) was used in view of detecting
fractured or weathered zones within the University of Abuja Staff Quarters, Gwagwalada,
Federal Capital Territory. The VLF -EM data measured along seventeen profiles of 400m at
inter profile distance of 25m and interstation separation of 10m were done using the Scintrex
ENVI Instrument. The VLF-EM survey revealed features significant to groundwater potential
as conductive zones in the Fraser Filter maps and current density pseudosections. Three distinct
zones were delineated based on the current density distribution. The fresh basement terrain
corresponds to the highly resistive zone with current density value less than -20. The
intermediate zone has current density value range of -20 to 25 typical of rocks and soil component which are slightly resistive to slightly conductive and corresponds to the partially
saturated units. The third zone is highly conductive with current density value greater than 30
which includes the saturated weathered or fractured basement, fault zones, clay units and saturated sandy units within the study area. The north eastern, north western (profiles 1-8) and
some parts of the southern region (profiles 16 and 17) of the study area show higher conductive zones than the central parts of the study area. This survey has helped in detecting sites that are
suitable for groundwater exploration by identifying water bearing fractures and weathered
zones in the study area. The areas with high conductivity response are areas with conductive
overburden material such as clayey soil, saturated soil, water filled fractures and faults or
weathered zone within the basement.
Open Access
Synthesis of carbon nanostructures using microwave enhanced chemical vapor deposition and its poten...
Kure Nicodemus, Yunusa Zainab, Hamidon M Nizar, Daniel H Isaac and Ibrahim I Lakin
abstract View article PDF
In this paper, Carbon Nanostructures (CNS) were directly synthesized on gallium orthophosphate (GaPO4). An alternative microwave enhanced chemical vapor deposition (MECVD) technique was used to synthesized the CNS via commercial microwave oven with operating power of 600 W at 2.45 GHz. Microwave heating provides the temperature for catalytic decomposition of polyethylene at 750 °C for 4 minutes under atmosperic pressure of 0.81 mbar. Characterization of the as-grown CNS was carried out using Raman spectroscopy and Field Emission Scanning electron microscope (FESEM). Raman spectroscopic investigation reveals the CNS quality of 0.92 and the field emission Scanning electron microscope (FESEM) analysis shows twisted hollow-like CNS structures. The material was deployed as a sensor without any post treatment so as to investigate its potential application in the sensor industry. Different concentrations of ammonia (NH3) gas from 0.06% to 1% were exposed.
Open Access
Integrated Geoelectric and Hydrochemical Methods to Evaluate Groundwater Pollution in Azikoro, Yena...
Bunonyo T Yemanai, Ulori Oritsebemigho and Obhuo P Esther
abstract View article PDF
This paper presents an investigation on the contamination potential of ground water using
integrated geoelectric and hydro chemical methods within Azikoro, Yenagoa, Bayelsa state,
Nigeria. The SAS 1000 ABEM Terameter was used to acquire the field data and IPI2win was
used to obtain three geoelectric layers result for the 1D VES point; with depth of 0 m, 0.91m
and 2.03m and thickness of 0.91m, 0.12m respectively with corresponding resistivity of 0.027
m and 0.00079 m, to show the subsurface lithology and water bearing level. RES2DINV was
used to interpret the data for the 2D imaging, with results indicating contamination spread in
profile 1 and 2 at depth of 6.94m and 9.94m respectively. Water samples from two boreholes,
near and after the vicinity of the cemetery were analyzed for electrical conductivity (EC), pH,
total dissolved solids (TDS), phosphorous, nitrates, chemical oxygen demand (COD),
potassium, sodium, sulfate and chloride. From the result obtained conductivity is very high due
to low resistivity. The water sample results were compared with World Health Organization
(W.H.O) permissible limit standard which indicated that the water is safe for consumption
within the period of investigation.
Open Access
Comparative Study on the Development of Composite Briquette as Alternative Fuel using Rice and Maiz...
Tasiu Jamila, Abdulrashid A Farida and Abubakar I Zainab
abstract View article PDF
In this study, the development of briquettes from agricultural waste mainly rice and maize husk
is presented. A 0.12 kg of each sample with a combination ratio of 1:1 was used in the buildup. The results obtained shows that, rice husk, maize husk and the combination of rice and maize husk have calorific value of 15.27 kJ/kg, 17.13 kJ/kg and 16.20 kJ/kg, moisture contents of 78.8 %, 86.8 % and 79.1 %, ash contents of 39.74 %, 18.07 % and 13.39 % and densities of 1084.3 kg/m3, 1011.5 kg/m3 and 1012.4 kg/m3 respectively. The research shows that briquette made from maize husk has the highest calorific value that can meet domestic use as an alternative fuel compared to briquttes from rice husk and the combination of rice and maize husk.
Open Access
Evaluation of Briquettes Produced from Four Selected Sawdusts Combination at Quaternary Levels...
Abdulkarim Mayere and Aaron L Shekarau
abstract View article PDF
The objective of this paper is to evaluate briquettes produced through quaternary level
combination of four types of common sawdusts from major wood sources. This was achieved
by producing seven briquettes made up of four primary sawdusts and three from
combinations of all primary saw dusts in rations of 25% each, 60/40 rations of A and B and C
and D and vice versa (i.e. 40/60 %). The sawdust samples are from four different wood species; Terminalia superba (Afara), Khaya ivorensis (Mohagany), Anogeissus leiocarpus (Marke) and Isoberlina doka (Ububa/Doka). The samples of the sawdust were collected from selected sawmills in Kaduna, Nigeria. Proximate analysis was applied when evaluating the
produced briquettes. The results of proximate analysis for the seven sawdust briquette
samples tested shows the range of values as; moisture content is 4.3 – 5.0%, ash content (0.7 – 4.2) %, volatile matter (81.5 – 90.8) % and fixed carbon (7.7 – 18.0) %. Calorific Values (CV) are within the range of (17.202 – 18.933) MJ/Kg. The results of proximate analysis of all seven sawdust briquette produced shows that heterogeneous sawdust samples at quaternary levels (or perhaps even at higher levels) of combination do not necessarily
produce briquette with much higher CV, as show in difference between the highest and
lowest CVs obtained with a difference of 1.072 MJ/kg.
Open Access
Assessment of Radio-Frequency Radiation from Selected Mobile Base Stations within Kaduna Metropolis...
Daniel Elisha, Daniel H Isaac, Muhammad S Abubakar, Kure Nicodemus, Philibus M Gyuk and Peter Anthon
abstract View article PDF
In this paper, radio-frequency radiation levels from some selected Base Transceiver Stations of different network providers (MTN, 9mobile, Airtel and Globacom) within Kaduna metropolis, Kaduna State, Nigeria were measured using a portable hand-held spectrum analyzer model 2658A, within radial distance intervals of 20 m to 100 m from the foot of each Base Transceiver Station. The measured values range between 0.24 μWm-2 to 30.42 μWm-2 with an average value of between 0.298 μWm-2 to 14.578 μWm-2 respectively. The measured radiation levels were found to be less than the acceptable standard value of 4.5 Wm-2 recommended by International
Commission on Non-ionizing Radiation Protection for Global System for Mobile communication with frequency 900 MHz. Results obtained show exposure to RF emissions
from the sampled Base Transceiver Stations will not impose health risk to humans living within that area.
Open Access
Economic and Environmental Analysis of Solar Powered Desalination
Abdulkarim Mayere
abstract View article PDF
In this paper the economics of a small-scale humidification dehumidification desalination
(HDD) unit driven by a concentrating v-trough solar thermal collector is explained. A
comparative analysis using the net present value method was carried out for when the system
is operated using solar energy and electricity from fossil fuels. The system could provide
different amount of fresh water depending on mode of operation. It was shown that by end of
year six the investment for the solar system reaches breakeven when compared to the electric
system. The analysis also considers the amount of carbon savings that could be achieved and
final cost of water produced per cubic meter. The factors that influence the systems economic
viability are the outputs and costs of the desalination unit and solar collector systems, the cost
of alternative energy source, cost of operation and maintenance, and the geographic location
of the system, i.e. solar intensity, environmental temperature and humidity.
Open Access
Automatic Power Sharing System for Generators
Abdulkarim Mayere
abstract View article PDF
In this paper, a proposal for the development of a neighbourhood network (n-network) automatic power sharing system that will bring about regulatory paradigm and mobilization of the private sector to lead in deployment of clean energy solutions while letting local residents to buy (consumer) and sell (producer) electricity among the neighbours is presented. Here the neighbourhoods become prosumers. Until now, electricity production and supply has
traditionally been implemented via a centralized grid where the power generation companies
otherwise known as Gencos generate electricity that is fed through the grid to individual homes. The proposed solution aims to create a peer-to-peer trading system where consumers will identify each other’s needs and willingness to buy and sell electricity. This offers the chance to bypass the traditional electricity grid and create a viable generation and storage micro grid that functions independently.
Open Access
Experimental Investigation of a Small Scale Humidification Dehumidification Desalination Unit...
Abdulkarim Mayere
abstract View article PDF
A psychrometric energy process desalination unit has been experimentally tested. The system is based on humidification and dehumidification process where seawater is heated and then sprayed to humidify the incoming air in the humidification chamber. The humidified air
enters the dehumidification chamber and is cooled by the incoming cold seawater. The
moisture is condensed out and the pure water is accumulated at the base of the chamber, and
the dehumidified air is discharged to the outside. The seawater was heated to temperature between 60 - 90°C using a 2.4kW electric heater. Performance data on temperature, seawater mass flow rate, air flow rate and the amount of fresh water produced were obtained, and the maximum coefficient of performance (COP) of the system was calculated based on the data obtained. The result achieved indicates the system had a maximum fresh water production of 13kg/h with a maximum COP of 3.6. The initial test shows that the system has great potential with room for improvements and further optimisation.
Open Access
Geophysical and Geotechnical Pre-Foundation Assessment of the proposed ICT center of the Olusegun A...
Banso O Emmanuel, Adefemi F Olasele and Bayode G Bamidele
abstract View article PDF
A geophysical and geotechnical pre-foundation study on the proposed ICT center of the
Olusegun Agagu University of Science and Technology (OAUSTECH), Okitipupa, was carried out to determine the suitability and competency of the subsurface soil and evaluate its
engineering implications for infrastructural development. The Dipole-Dipole array, with a
spacing of 5 meters, was used to investigate the subsurface lithology and its suitability for
construction application in relation to the depth, thickness, and resistivity of subsurface
materials. Three (3) traverses, 110 meters each, were employed. Four (4) soil samples randomly
taken at depths of 0.5 meters were used to carry out geotechnical laboratory tests. The first
layer resistivity ranges from 153 ohm-m – 1005 ohm-m with maximum thickness of
approximately 2 meters, the second layers resistivity value ranges between 1162 ohm-m to
84965 ohm-m with corresponding thickness of 10 meters – 15 meters, and the third layer has
resistivity values above 221486 ohm-m. Geotechnical analysis carried out on the soil samples
obtained are Natural Moisture Content (NMC) with values between 14.1% to 14.3%, Grain
Size Analysis with > 50% finer passing, Atterberg Limit Test with plastic limit ranging from
19.4% to 19.9%, Consolidation test ranging from 0.0131 – 0.0136m²/yr, Unconfined
Compression (UC) Test revealing approximately 182.5Kla, Permeability test ranging from
1.33×10-5 cm/s to1.85×10-5 cm/s, and Specific Gravity (SG) of 2.648 - 2.654. Three geological
layers were inferred namely; clayey sand, sandy clay and sand. From the geophysics and
geotechnical it can be inferred that the study area is competent. But Excavation of soil to a
depth of about 2 meter at which the soil is adequately competent (consolidated) is
recommended.
Open Access
Synthesis and Characterization of Semiconducting Iron Copper Sulphide Thin Films: A Review
Joseph O Emegha and Ezeamaka D Nwanze
abstract View article PDF
Iron copper sulphide (FeCuS) thin films have attracted much importance due to their
exceptional properties for device applications. The chemical deposition techniques of
chemical bath deposition (CBD) and Successive ionic layer absorption and reaction (SILAR)
have been employed to synthesize FeCuS thin films with good substrates adhesion. The
various advantages and shortcomings of these methods were discussed with their capability to
control the morphology and opto-electrical properties of the films. The experimental
measurements indicated that the films exhibit great potential for optoelectronic applications
such as window materials in solar cell fabrications and coatings of different types. Due to the
current interest in FeCuS thin films, this review is intended to provide current information on
the synthesis, characterization, and applications of iron copper sulphide thin films.
Open Access
Analysis of VLF-EM Data for Potential Cassiterite Mineralization Delineation Zone in Rafin-Bareda A...
Micah Adamu, Nasir K Abdullahi and Dogara D Matoh
abstract View article PDF
VLF-EM geophysical technique was employed to delineate potential cassiterite mineralization
at Rafin Bareda, Dutsen-Wai, Kubau Local Government area of Kaduna state, North Western,
Nigeria. A total area of 3.025 km2 was covered along eleven (11) traverses separated by 25m
with a measurement interval of 10m taken in the East-West direction. The response of the inphase component revealed various anomalous zones while Fraser-filtered plots of the in-phase
peaked over the anomalous zones and the Karous-Hjelt filtered response of the in-phase
correlates quite well with the results of the Fraser filtered data. In order to achieve the aim of
the investigation, and since the VLF data was collected in the magnetic mode, enhancement
procedures such as reduced to equator and analytical signal techniques were applied to the
Fraser Filtered response of the In-phase component and correspondingly, Center for
Exploration Targeting (CET), Source Parameter Imaging and Euler Deconvolution algorithms
of the Oasis Montaj were successively employed to delineate potential mineralization zones
and best locations for drilling productive cassiterite in the study area. Enhanced maps show
linear features trending in the NE-SW and NW-SE directions with minor traces in the N-S
direction. Most of the delineated zones of high analytical signal signature were either
intercepted or flanked by the extracted lineament which is indicative of positive correlation
between the extracted lineament and the high amplitude response of the analytical signal and
also, validated the occurrence and positioning of the cassiterite mineral deposits is greatly
controlled by the lineament system across the study area and the development of conductive
zones of high apparent current with positive values reflects inferred subsurface structural
fractures and/or mineralized zones. Depths evaluation analysis from the Euler Deconvolution
(ED) technique using structural index of 1, ranged from 5 m to 15 m while depths varying from
4.9 m to 13.7 m were obtained from the Source parameter imaging technique.
Open Access
A Study on the Effect of Eu3+ dopant on Physical and Photoluminescence Properties of Zinc Phospho-S...
Garba M Ephraim, Akut Anna, Markus Gloria, Thomas L Wancy and Daniel H Isaac
abstract View article PDF
In this paper, the effect of substituting europium (Eu3+) ion on physical and photoluminescence
properties of zinc phosphor-sulfo-tellurite glasses is reported for the first time. The glass
matrices with novel compositional range of 10ZnO–40TeO2–10SO3–(40-x)P2O5– xEu2O3 were
synthesized by convectional melt-quenching route and characterized via density and
photoluminescence (PL) measurements. The non-linearity properties of these glasses was
ascertained and dependence of red emission performance under λex= 394 nm excitation
wavelengths disclosed bright red emission at λem. = 612nm. The concentration quenching
phenomenon was observed after a particular value of europium ions (beyond 2 mol %). Thus,
2 mol% of Eu3+ in the glass composition was identified as the optimized concentration for the
design and development of solid state red laser and color display devices.
Open Access
Estimating Geothermal Energy Resource Potential within Jema’a Local Government Area of Kadun...
Garba M Ephraim, Afuwai G Cyril, Mamman G Ayuba and Joseph I Abaleni
abstract View article PDF
This study used aeromagnetic data of Jema’a, sheet No.188 to estimate the geothermal energy resource potential in Jema’a Local Government Area of Kaduna State, Nigeria. The study area lies between latitude 9°11' and 9°27' N and longitude 8°00' and 8°17' E. Total magnetic intensity (TMI) map of the area was produced from the gridded data. Residual map was obtained by removing regional field from the TMI which was divided into 36 blocks for spectral analysis. The centroid depth (Z0) was obtained by dividing the gradient of the lengthiest wavelength part of the spectrum by the wave number. The depth to top (Zt) of the magnetic source was obtained from the gradient of high wave number portion of the power spectrum. The values of Z0 and Zt were used to obtain the values for depth to bottom of the magnetic source (ZB). The geothermal gradient (dT/dZ) values were obtained by dividing 580℃ by ZB while the heat flow (q) values were obtained by multiplying dT/dZ by the constant k (2.51).The dT/dZ values obtained range from 13.560 to 4000.000℃/km with an average value of 46.393℃/k and having the least (13.560 ℃/km) around Kafanchan axis and the highest (4000.000 ℃/km) around Sanga. The q values range from 34.036 to 1004.00 mW m^(-2) with an average value of 118.089 mW m^(-2). The dT/dZ values were observed to be greater than 100 mW m^(-2) around Sanga and Andaha axes. The Curie depth (28 km) was deepest at the South-South, South-East and South-West regions. Since magnetic properties of minerals disappear at this temperature and thermal conductivity of rocks increases with depth, these areas are potential geothermal energy source.
Open Access
Assessment of Groundwater Yield Potentials Zones of Idi-Ayunre using Vertical Electrical Sounding a...
Magi F Fredrick, Olajide A Temitayo and Olajide O Adetayo
abstract View article PDF
To fully harness the increasing number of observations and variant data sets available and put them to efficient use in geological studies aimed at solving earth science-related problems, GIS technique is a veritable tool. The dynamic techniques and the complex nature of earth sciences
is a serious cause for worry for geologists. In this work vertical electrical sounding (VES) was
integrated with geographic information system (GIS) to delineate subsurface characteristics and evaluate groundwater potential zones in Idi Ayunre, Oluyole Local Government Area, Oyo State. The results of the VES curves obtained from the partial curve matching were used to constrain the interpretation by the computer using iteration software known as WINRESIST®
and extended analysis on the data set was done using geostatistical analysis tool on archGIS 10.0®. The Root Mean Square (RMS) errors for the analysis were found to be very low with an average of 2.96% . This underscores the reliability of the analysis tool for this type of work. The area is dominated predominantly by Type-H curves which amassed twenty (20) out of the twenty-one (21) VES and one (1) VES producing a type-K curve. The VES results revealed a
maximum of three geo-electric layers, viz: topsoil, weathered layer, bedrock respectively. The
yields of wells dug in most of these locations may be insufficient, even for domestic use because of its relatively small thicknesses. However, at a depth of 7.8 m, a fractured zone occurs in VES 10 with resistivity value of 21.2 Ωm suggesting the presence of groundwater, which may be
considered the main aquifer units suitable for groundwater exploration.
Open Access
Assessment of Heavy Metal Loadings of Water and Sediment of River Enumabia in Orokam, Benue State, ...
Emmanuel D Onoja, Matthew I Amanyi, Elijah E Onwoke, Inalegwu A Ngbede and Bashiru Lukuman
abstract View article PDF
Enumabia being the only surviving river in Orokam community gave us the concern to assess the concentration of heavy metals in water and sediment in the river. 20 samples of water and Sediment were taken from four (4) different points 20 meters apart and analysed for heavy metals by the use of AA-700 Dual Atomizer Atomic Absorption Spectrophotometer in Energy
Research Centre, University of Nigeria, Nsukka. In water, the concentration of Fe ranges from
0.7669 to 0.9214 mg/l, Pb ranges from 1.3300 to 1.7210 mg/l, As ranges from 0.9032 to 2.0120
mg/l, and there was no concentration of Hg, Cr and Al. The concentration of metals in the water samples are at the range of permissible limit set by World Health Organization (WHO) except Pb, and As that are fairly higher than the permissible limit. In sediment, the concentration of
Fe ranges from 128.8812 to 113.9563 mg/l, Pb ranges from 0.2500 to 0.9520 mg/l, Cr ranges
from 0.1240 to 0.6676 mg/l, Al ranges from 10.0000 to 16.0000 mg/l, As ranges from 0.0000
to 1.1240 mg/l, Cu ranges from 0.2420 to 0.8490 mg/l and there was no concentration of Hg.
The concentration of Fe, Pb, Cr and As in the sediment exceeded the standards set by WHO.
This presence could be detrimental to plant, human being and aquatic life. Since there is fast accumulation of toxic and carcinogenic metals present in the water and sediment samples collected from Enumabia River in Orokam there is need for a follow up study to determine how the human and aquatic lives have been affected.
Open Access
Preliminary Investigation of Soil and Sediments Using Magnetic Susceptibility Method in Kogi State,...
Jatto S Solomon, Nwodo M Ogechukwu and Kizito O Musa
abstract View article PDF
Over the years, there has been significant increase in population and urbanization in Kogi State as a result of rural - urban migration. This has become a major threat to soil sustainability which is a natural non-renewable resource. The aim of this research is to carry out magnetic susceptibility mapping on the surface and subsurface soil of Kogi State using environmental magnetism techniques and geochemical analysis. The susceptibility test on rock samples and background soil samples within the study area shows an average of about 112.0 × 10^-5 SI. The magnetic susceptibility measurement on soil from Kogi State shows magnetic susceptibility enhancement of about (450.0 - 700.0) × 10^-5 SI. These values were dominant along the major towns, road pavements and commercial areas at the surface to a depth of about 50.0 cm in soil profiles. The 2D spatial distribution of magnetic susceptibility with depth reveals that theses magnetic grains are distributed in the subsurface as a result of anthropogenic loading. The frequency-dependence of magnetic susceptibility (χfd%) values are very low (2 - 10.0 %) in most of the areas on the surface soil. This values indicate that the magnetic properties are predominantly contributed by the coarse multi - domain (MD) and stable single domain (SSD) grains of anthropogenic origin. Atomic Absorbtion Spectrometer (AAS) analysis of these soil samples indicates the presence of Lead (300.0 - 900.0) mg/l and Cadmium (20.0 - 60.0) mg/l in large concentration at the surface soil in most part of the Kogi State. While Chromium show relatively low concentration on the surface soil. From the statistical correlation analysis, Lead and Cadmium show high positive correlation with magnetic susceptibility. These results suggests that the high enhancement of magnetic susceptibility on the surface and sub-surface soil in most part of Kogi State arise from anthropogenic activities rather than lithological and pedogenic processes and most likely cause by high concentration of Lead and Cadmium.
Open Access
Effect of Indiscriminate Hydrocarbon Exploration on Possible Occurrence of Earthquake in some parts...
Damilare S Adepehin, Muhammad S Ahmad and Opeyemi R Omokungbe
abstract View article PDF
Seismic activities leading to tremors have been a subject of interest in geophysical survey. Here in, we reported the (seismic) tectonic activities of Langbodo field, an area where tremors have occurred in the Niger Delta, Nigeria. The seismic data used in this research work were analyzed using the CPillar® and the Plaxis 2D® seismic softwares. These softwares are based on sensitivity, probabilistic and finite element analyses. The variation in the depth of the exploration boreholes for the five identified locations, LCT A, LCT B, LCT C, LCT D and LCT E with respective values 7525 km, 7000 km, 8000 km, 7600 km and 9000 km showed the extent to which the underlying crust can be pressurized. The seismic information from the drilled wells revealed that the tensional force created through stress ranges from 5.517 × 10^13 N to 6.130 × 10^14 N and that of compression ranges from 3.065 × 10^14 N to 5 517 × 10^14 N. The tectonic activities of each of the locations were recorded using the seismic reflection method. This study revealed that more than 50 % of the earth tremors experienced in the area were humanly triggered. Seismic records of the areas showed that human activities that result to rapid injection of fluid into the plates, if not controlled, can trigger tremors. The magnitudes of tremors that have occurred in the five identified locations LCT A, LCT B, LCT C, LCT D and LCT E are respectively 3.50 ML, 3.20 ML, 4.20 ML, 4.00 ML and 4.32 ML. This research work however concluded that the study area is likely to witness earthquakes of about 7.0 ML magnitude should explorations continue indiscriminately. Probable occurrence of earthquakes in this location can be nipped in the bud by setting up agencies that monitor and assess subsurface pressures, quantities of injected fluid, volume of extracted fluid, and the seismicity of vulnerable regions with time.
Open Access
Shale Volume Effect on Hydrocarbon Prospectivity of Green Field, Niger Delta, Nigeria
Damilare S Adepehin, Fredrick F Magi, Abimbola I Odudu, Moromoke O Adelayi, and Kennedy Suleiman
abstract View article PDF
his research presents an investigation on the shale volume effect on hydrocarbon prospectivity of Green Field within Niger Delta, Nigeria. Delineation of potential reservoirs was done with Petrel Version 2010® and OpendTect 4. 6.0® exploration and production softwares, and data obtained were quality checked to eliminate null values. Three different empirical models were used to estimate the shale volume for fifteen delineated reservoirs from the three identified “Green†wells. The shale volume ranges from 0.111 to 0.162 for Green 1, 0.056 to 0.092 for Green 2 and 0.007 to 0.140 for Green 3 reservoirs. An average shale volume obtained from a merger of the three models was compared to the permeability in each of the fifteen reservoirs to determine the hydrocarbon prospectivity of the wells. It was noticed that shale volume increases with a decrease in the permeability. The ratio of shale to sand ranges from 0.125 to 0.192 for Green 1, 0.059 to 0.101 for Green 2 and 0.007 to 0.111 for Green 3 reservoirs. The presence of sand in higher volume which ranges from 0.838 to 0.889 for Green 1, 0.908 to 0.944 for Green 2 and 0.900 to 0.993 for Green 3 reservoirs than shale which ranges from 0.111 to 0.162 for Green 1, 0.056 to 0.092 for Green 2 and 0.007 to 0.140 for Green 3 reservoirs and higher resistivity which ranges from 5.61 to 96.93 for Green 1, 16.01 to 103.42 for Green 2 and 14.75 to 22.17 for Green 3 reservoirs than the conductivity which ranges from 0.0100 to 0.1800 for Green 1, 0.0096 to 0.0625 for Green 2 and 0.0450 to 0.0680 for Green 3 reservoirs are some major signals confirming a substantial hydrocarbon in the reservoirs. Results from this study indicates prospective presence of fractured shale deposits in the study area. Petrophysically, subsurface reservoirs in the “Green†field have reasonable hydrocarbons in their pore-spaces and estimated producibility indicators are good enough to support secondary migration of the oil into the borehole, if developed.
Open Access
Investigation on the Effect of Imbalance and NonLinear Load on 11 kV Pama Feeder
Daniel C Bamaiyi, Daniel H Isaac, Alhassan Shuaibu, Kure Nicodemus and Gyuk M Philibus
abstract View article PDF
In this research the effect of imbalance and nonlinear load on power quality was investigated via the electronic method with the aid of a Fluke 435 power quality analyser and the results obtained compared with IEEE standards. The study was carried out on 11 kV Pama feeder Kaduna state, Nigeria, which is comprised of Nassarawa, Boro1, Pama 1, Pama 2, and Pama 4 substation. The analyzed result shows an average value of 230 and 1327 times voltage dips and swells, 11.74 % harmonics current, 2.33 % harmonic voltage, 5.96% imbalance voltage and 25% imbalance current respectively. When compared with the IEEE standard limits of 5 % and 2 % harmonic current and voltage, 10 % and 5 % imbalance current and voltage, it could be seen that these results imply the presence of harmonics within the system which are fundamentally due to imbalance and non-linear load, triggering operating complications on the distribution system. These complications include load disruptions, over current, over voltage, heating, leading to forceful outage, increased power losses, faster ageing of insulations, unstable power supply, burnt cables, sockets and connectors, thus reducing capacity and ultimately resulting in premature failure of transformer.
Open Access
Study of Rain-Induced Signal Degradation of Terrestrial Radio Links within Minna and Lapai, North-C...
Tyabo A Muhammad, Oyedum O David, Ayantunji G Benjamin, Elemo O Enoch, Muhammad B Ladan, Jibrin A Yabagi, and Ndanusa Babakacha
abstract View article PDF
Rain attenuation is a major source of impairment to signal degradation at millimetre wave bands above 10 GHz. This research work determines the extent of signal degradation due to rainfall on terrestrial radio links within Minna and Lapai. The meteorological rainfall data collected from the Automatic Weather Stations installed at the Federal University of Technology, Minna, and at Ibrahim Badamasi Babangida University, Lapai, for a period of 3 years (2011-2013) were used to computate the rainfall attenuation on Microsoft Excel spreadsheets. The Lavergnat-Gole (LG) model was used for the conversion of cumulative distributions of rainfall of 5-min to 1-min integration time in Minna and Lapai respectively. The LG model was used to estimate the rain attenuation in the two stations at a frequency range of 10-18 GHz. The relationship between rain rate and specific attenuation was studied using three years rainfall data. It was observed that a power-law relationship exists between rainfall rates of different integration times. The results for the rain rate exceeded for 0.01% of time, show that the horizontal polarisation experiences more degradation than the vertical polarisation. The results also show that specific and total attenuations increase with increasing operational frequency, and are polarisation-dependent. These results would be useful for planning terrestrial radio networks within the study area.
Open Access
Composite Estimation of Permeability in Identified Hydrocarbon Reservoirs of Langbodo Field Niger D...
Damilare S Adepehin, Oluwaseyi A Dasho, Matthew I Amanyi, Ayodeji B Babinisi, Abdulazeez O Salawu, Stephen O Adikwu, Emmanuel D Onoja and Inalegwu A Ngbede
abstract View article PDF
This study identified the fluid types and boundaries present within selected reservoirs in Langbodo field, using petrophysical parameters based on estimated rock properties such as porosity, permeability, irreducible water saturation, hydrocarbon saturation and bulk water volume. This was with a view to correcting the salient reservoirs heterogeneities anomalies error inherent in building of an ideal realistic reservoir models. The quality of the data obtained were checked and despiked to eliminate null values. Petrel version 2009 and OpendTect 4.6.0. Exploration and production softwares were used for the quality interpretations of data, such as lithology identification, delineation of potential reservoirs and determination of fluids and fluids contacts. Estimation of quantitative petrophysical parameters were done by inputting the data into Microsoft excel 2015 version softwares and adopting appropriate mathematical relations, such as the Tixier, Timur and the Coates and Dumanoir models for the permeability (K). Realistic estimation of the permeability was done by comparing the average of the Tixier, Timur and the Coates and Dumanoir models with each of the models. The composite model obtained, mirrors the behavior of the Timur’s permeability which is higher than that of the Tixier and the Coates and Dumanoir. Integration of the Achie’s equation and neutron – density crossplot confirmed the presence of substantial hydrocarbon in the reservoirs, although producibility indicators revealed that the reservoirs may not be producible without enhanced oil recovery method(s). This study established that the composite model is a better representation of K in the study area because it agrees with the Timur’s estimation model.
Open Access
Nickel Deposit Depth Estimation Using Source Parameter Imaging and Euler Deconvolution of Aeromagne...
Garba M Ephraim, Afuwai C Gwazah, Matoh D Dogara and Mamman G Ayuba
abstract View article PDF
This study aimed to estimate the depth of Nickel deposit in Bakin Kogi – Dangoma region, which lies between latitude 901''and 9027'N and longitude 8000' and 8017' E. The study area is located in Jema’a local government area of Kaduna state. The data was gridded using Oasis Montaj® to produce Total magnetic Intensity Map (TMI) of the area, and further subjected to some filtration processes in order to obtain regional and residual map of the study area. Enhancement methods such as first vertical derivative and analytic signal methods were applied to the residual map to delineate the area with potential Nickel deposit. The quantitativemethod applied were source Parameter Imaging and Euler Deconvolution to determine the various depths of Nickel deposit. From the results of the TMI map and the residual map, the magnetic intensity of the study area was between 32976.5 to 33093.3 nT and 32963.6 to 33072.9 nT respectively with Bakin kogi-Dangoma region, having the highest magnetic intensity of about 33093.3nT and 33072.9 nT respectively. The study area has a high magnetic intensity due to nickel deposit because Nickel ore environment are notable with recognizable “magnetic stratigraphyâ€, prospective mafic-ultramafic contact, typified by strong magnetic contrast. Abrupt changes in the magnetic intensity infer position of the outer contact of a Nickel bearing zone. The results on the superimposed analytic map on the lineament map showed regional lineaments in Bakin kogi-Dangoma region trending NE -SW, ENE – WSW and NNE – SSW directions. The fractures and faults seen around the study area were strongly associated with minerals deposit. The results of Source Parameter Imaging (SPI) gave a depth of shallower magnetic sources ranges from 92.7 to 116.0 m with an average depth value of 104.35 m while the depth of deeper magnetic sources ranges from 651.2 to 976.2 m with an average depth of 813.7 m. The results obtained from 3D Euler deconvolution which was associated with dykes (SI = 1) anomaly produced at a shallower depth range of 100 - 700 m. Results obtained, shows a correspondence between the depths results obtained from the SPI and that of the Euler Deconvolution methods, indicating correlation in the magnetic depth estimation.
Open Access
Optimization of Absorber and ETM Layer Thickness for Enhanced Tin based Perovskite Solar Cell Perfo...
Eli Danladi, Abdulazeez O Salawu, Muhammed O Abdulmalik, Emmanuel D Onoja, Elijah E Onwoke and Damilare S Adepehin
abstract View article PDF
The methyl ammonium tin iodide (Ch3Nh3SnI3) perovskite nanocrystals have attracted research interest and have become a rising star in the horizon of photovoltaics due to its narrow band gap, wide visible absorption coefficient and environmental friendliness than its lead-based counterpart (Ch3Nh3PbI3) . In this article, a tin based perovskite solar cell with Zinc oxide (ZnO) and Copper Oxide (CuO) as electron transport medium (ETM) and hole transport medium (HTM) was proposed and investigated numerically using a Solar Cell Capacitance Simulator (SCAPS) tool. With appropriate parameters, a short-circuit current density (Jsc) of 27.56 mA/cm2, open-circuit voltage (Voc) of 0.82 V, fill factor (FF) of 59.32 %, and power conversion efficiency (PCE) of 13.41 % are obtained for the initial simulation. By varying the thicknesses of the absorber and electron transport layer, the optimum thicknesses were observed at 0.6 um and 0.3 um for Ch3Nh3SnI3 and ZnO with corresponding PCEs of 14.36 % and 13.42 %. Upon simulation with optimized parameters, a Jsc of 29. 71 mA/cm2, Voc of 0.83 V, FF of 61.23 % and PCE of 15. 10 % were recorded. These values are superior to those obtained without optimization which means that solar cell performance can be improved to some extent by adjusting the perovskite and electron transport layer and also, Ch3Nh3SnI3 Perovskite solar cell (PSC) is a potential environmentally friendly solar cell with considerable efficiency.
Open Access
Diurnal Variation of Surface Radio Refractivity over Sokoto, North-western Nigeria
Mohammed Z Doko, Oyedum O David, Muhammad B Ladan, Jibrin A Yabagi, Ndanusa Babakacha, Abdullahi A Saba, and Franscious Cummings
abstract View article PDF
The knowledge of good refractivity profile is vital for proper planning of terrestrial communication links; surface refractivity profile of a station is particularly required for enhanced planning and prediction of performance of terrestrial radio links especially in tropical regions where International Telecommunication Union Recommendations (ITU-R) has called for such local propagation data. The diurnal surface radio refractivity Ns over Sokoto was investigated for a period of three years (2008-2010). High values of Ns were recorded in the early morning hours while low values were recorded during afternoon hours. The least mean hourly Ns varied between 270-280 N-units in January (a typical dry season month in Sokoto) while the mean maximum was recorded between 345-360 N- units in July (a typical rainy season month). Also, average seasonal variation of Ns was 356-440 N-units in rainy season and 270-285 N-units in dry season. The result of this investigation also showed that relative humidity and temperature have major influence on the variation of surface radio refractivity, while pressure has relatively less influence. The study further showed that coverage of a radio transmitter of 200 m height may have a variation of up to 0.5 km between morning and afternoon hours in Sokoto.
Open Access
Washable Stitched Transmission Line for Wearable Applications
Isaac H Daniel, Ibrahim Umar, Nicodemus Kure and Abdullahi A Kassimu
abstract View article PDF
n this paper the washability of a stitched transmission line is been studied. The aim is to determine the deterioration of the frequency dependence of the scattering parameters of the stitched transmission line after subjecting it to washing cycles using a domestic washing machine. The DC resistance of the stitched transmission line was measured before and after wash with results indicating an increase in the DC resistance from 16.9 Ω to 22.8 Ω after washing the stitched transmission line. The increase in DC resistance is due to the decrease in conductive path of the stitched transmission line as a result of the abrasion impacts in the washing machine leading to increased number of fissures and defects on the stitched transmission line. The propagation characteristics of the stitched transmission line were investigated using CST Microwave Studio Suite® and measurements on the stitched transmission line before and after wash was carried out using an Anritsu MS46524A 7GHz Network Analyser for a frequency range of 0.04 to 4 GHz, with results demonstrating that the stitched transmission line will make a good candidate for wearable applications.
Open Access
Study of Seasonal Surface Refractivity over North-Central Nigeria
Jibrin A Yabagi, Ndanusa Babakacha, Mohammed I Kimpa, Mohammed Z Doko, Abdullahi A Saba, Umar Sadiq, and Francious Cummings
abstract View article PDF
Tropospheric radio wave signals experience loss due to multipath effect, scattering and other forms of attenuation through the atmospheric medium, primarily due to variations in weather conditions with time. The knowledge of surface refractivity profile is important for optimal planning of Very High Frequency/Ultra High Frequency (VHF/UHF) terrestrial radio links in a region. The study of surface refractivity (Ns) over the North-Central Nigeria was carried out using meteorological data from seven locations in North-Central zone of Nigeria. The seasonal variations of Ns were also derived using the monthly summaries of surface data obtained from Nigerian Meteorological Agency (NIMET) over seven stations of Abuja, Lafia, Lokoja, Makurdi, Jos, Minna and Ilorin between 2005 and 2010.The results indicated that the monthly averages of radio refractivity during the rainy season months (April to October) are greater than the Ns values during the dry season months (November to March) for all the locations throughout the years of the study. The computed of mean monthly Ns over all the seven stations in the first 1 km above the ground level is 348 N-units, which gives mean refractivity gradient (dN/dh) of -49 N/k, these shows that the region is characterised by low scale super-refraction. The mean k-factor over the entire region in the first 1 km above the ground level is 1.4; the mean Field Strength Variability (FSV) in first 1 km of height in the region was calculated to be 14 dB. The mean Radio Horizon distance within 1 km height for a transmitter height of 100 m over the stations is 42 km. The results provide useful information needed by radio engineers to set up new terrestrial radio propagation links or to improve on the existing ones especially at VHF, UHF in the North-Central region of Nigeria, as recommended by International Telecommunication Union Recommendations (ITU-R P.453, 2013), which observed the need for local reference data on refractivity and refractivity gradients all over the world.
Open Access
Power Density Measurement within Kaduna North Area of Kaduna State, Nigeria
Bello I Ayodeji, Nicodemus Kure, Isaac H Daniel, Emmanuel J Adoyi, Esther N Obiechile and Fidelis Yunusa
abstract View article PDF
The measurement of possible presence of radiofrequency (RF) radiations from telecommunication base stations was carried out within Kaduna North Area of Kaduna State, to estimate the maximum level of power density from RF radiations to which the member of the populace within specific radius from the base transceiver station (BTS) are exposed to in relation to the existing guidelines to human exposure. Power density S (µWm-2) measurements were made at interval of 20 m to check the exposure level at public locations from 10 RF antenna sites starting from the foot of each BS to distance (radius) of 100 m using Aaronia Spectran HF-4060 Analyser and the electric field strength E (Vm-1) were calculated. The highest and lowest value obtained from measured mean power densities were 108.27 µWm-2 and 94.74 µWm-2 from a distance of 100 m and 40 m respectively. Also, the highest and lowest average electric field strength were 202.03 (Vm-1) and 188.99 (Vm-1) at 100 m and 40 m respectively. The result obtained, indicates that the measured values were far less than the permissible exposure limits for both workers and the general public as set by the International Commission on Non-ionizing Radiation Protection (ICNIRP). These results shows that the exposure levels in these areas are low and as such will not pose significant health risks to the people living in the study area.
Open Access
Detection Efficiency of a NaI (Tl) Gamma Level Radioactivity Spectrometry System for Measurement of...
Biere P Ebibuloami, Ogunremi Ayorinde, Aina J Oluwagbenga, Emumeja e Kugbere, Olaoye M Adeola and Mustapha A Olalekan
abstract View article PDF
Qualitative analysis of radionuclides requires the use of reliable gamma-ray detection system. The NaI (Tl) detector has been widely used and still one of the most used detectors today. It is therefore imperative to validate the reliability of the 5×5 cm^2 NaI (Tl) gamma spectrometry system used in carrying out gamma-ray analysis of soil samples in the Radiation and Health Laboratory, Federal University of Agriculture Abeokuta, Nigeria. The gamma ray spectrometer is housed in a 5 cm thick cylindrical lead shield. Calibration was executed using standard materials produced under the auspices of the International Atomic Energy Agency (IAEA). Resolution and detection limit (LD) of the detector were determined using full width at half the maximum of the energy peak of 137Cs and background signal level of the reference materials respectively. Counting efficiencies of the detector was calculated using energies of 1460keV, 1764 keV and 2615 keV for 40K, 226Ra and 232Th respectively. Secondary samples, RGMIX1 and RGMIX2 were formulated and counted to calculate activity concentrations using the NaI (Tl) detector. Resolution of the detector was calculated to be 7.8% of 137Cs, which is good for a NaI (Tl) detector. The counting efficiency of the detector is seen to depend on the gamma ray energy. The results from this work shows that the detector system is suitable for gamma spectrometry, and will give quality measurements when used for quantitative determination of radionuclides in environmental samples. The efficiency and resolution of the NaI (Tl) detector could also be determined using photon energies obtained from other radioactive sources.
Open Access
Effect of Doping Concentration on Structural Stability and Formation Energy of the Fluorine Doped H...
Yakubu A Tanko, Alhassan Shuaibu, Aminu Abdulrahman, Oyedare P Olusola , Mustapha Isa and Aminu S Yamusa
abstract View article PDF
The structural properties of undoped and Fluorine doped Hexagonal Molybdenum dioxide (MoO2) with different doping concentrations have been calculated using Density Functional Theory (DFT) within Generalized Gradient Approximation (GGA) as implemented in Quantum
Espresso (QE). The calculated results were for the formation energy of 4.17%, 8.33%, 12.5%,
of F doped MoO2 are 232.5eV, 463.0eV, and 698.5eV respectively, which show the variation of energy based on the increase in the doping concentration that led to having the breakage of bond in the structure of the compound. The undoped and 4.17% of F doped MoO2 have three free atoms, which maintain the stability of the structure, but when the doping concentration was
increased, the bond breaks simultaneously which led to having four and five free atoms for 8.33%, and 12.5% of F doped MoO2 respectively. This makes 4.17% of F doped MoO2 with
17.09Ry more stable. Similarly, the bond length of undoped MoO2 was 2.2505pm, but when doped with 4.17% of F it changes to 2.3030pm which indicates a greater stability of the
structure concentrations of the dopant above 4.17% reduced the bond length, which made the
structure less stable.
Open Access
Geophysical Investigation of a Fault Zone from Aeromagnetic Data over the Ageva Area of Okene Kogi ...
Ahmed A Lawal, Adamu Abubakar and Avazi O Victor
abstract View article PDF
High-resolution aeromagnetic data over a part of Ageva fault zone in Nigeria have been
analyzed with a view to estimate sedimentary thicknesses within the studied area. The data set
of this study area, was subjected to various corrections and interpretation techniques. Regionalresidual correction was done and the noise level of the data was reduced via upward
continuation to a height of 250 m thereby enhancing the reliability of the results obtained. Qualitative interpretation techniques which include: Second Vertical Derivative, Analytic Signal, Tilt derivative were used to delineate the trending pattern of the anomalies in the study
area which are in the E-W, NE-SW, NW-SE, and N-S directions. The result suggests that fault zone within Ageva and Owo may be mineralized and also that the faults within Ageva and Ibilo
extend by a quarter of their exposed length. The Werner solutions revealed that inferred faults within Owo and Ibilo may have relatively low susceptibilities as compared with others in the
study area and the range of the depth extent of linear features is 401.5 m – 982.5 m.
Open Access
Paleomagnetic Susceptibility Distribution and Geochemical Analysis from the Eastern Part of Kalamba...
Adamu Abubakar, Faruk Usman and Musa M Zayyanu
abstract View article PDF
Magnetic measurements, mineralogical and geochemical studies were carried out on surface soil samples in order to delineate susceptibility distribution and to find possible relationships based on paleomagnetic implications in some part of Kalambaina Area of Sokoto Northwestern Nigeria. Geomorphologically, this area is generally gentle, with occasionally tabular, capped
by resistance laterites. Elevation generally decreases towards the northwest around the Nigeria
- Niger Republic boarder with an average elevation of about 215 above mean sea level. A total of 90 sample were measured at random with DSM-10 susceptibility Kappa metre as well
20 core drilling samples were collected for further XRF geochemical analysis. Mass specific susceptibility value ranges between 11.2 × 10^-6 SI and 1.4 − 8.2 × 10^-6 SI and magnetic remanence at 1 T values range between 10 × 10^-6 SI and 0.5 − 9.0 × 10^-6 SI as well as 0.5 − 7.4 × 10^-6 SI. Chemical analysis by Xray Fluorescence analysis revealed the presence concentration of various elements with their percentage composition (%) and the percentage composition of calcium carbonate (CaCO3) content between > 40% and < 70%, > 70% and < 80%, core drilling depth and overburden thickness of a limestone Layer and Overburden. Has also revealed low- and high-grade calcium carbonate CaCO3content.
Open Access
Subsurface Investigation of Basement Structures Using Electrical Resistivity Methods at Zainawa Vil...
Ahmed A Lawal and Adamu Abubakar
abstract View article PDF
Electrical Resistivity Methods involving Schlumberger Vertical Electrical Sounding (VES) and
Wenner Electrical Profiling (EP) were carried out to map the Geological features of the earth
subsurface in Zainawa Area of Kano State, Nigeria. Five profiles were established; consist of
six (6) VES points at each profile. GEOPULSE resistivity meter (SAS 300) was used for the data acquisition. The field data obtained have been analyzed using computer software (IPI2win) which gives an automatic interpretation of the apparent resistivity. A maximum of three geoelectric subsurface layers were delineated from the VES master curves. The geoelectric section beneath the study area was composed of top soil (clayey-sandy and sandy-lateritic), weathered layer, partly weathered (fractured basement) and fresh basement. The resistivity value for the topsoil layer varies from 20 Ωm to 600 Ωm with thickness ranging from 0.5 to 7.2 m. The weathered basement has resistivity values ranging from 15 Ωm to 593 Ωm and thickness of between 2.75 to 33.04 m. The fractured basement has resistivity values ranging from 201 Ωm to 835 Ωm and thickness of between 11 to 20.4 m. The fresh basement (bedrock) has resistivity values ranging from 1161 Ωm to 3115 Ωm with infinite depth. The depth to basement map was produced to give a good picture of the basement topography within the study area. The depth to basement ranges from 11 m around VES 01 to 85 m around VES 25 m. The map also reveals linear structures (VES 05, 21, 22 and VES 23) which trends in the NE-SW direction. These structures suggest a basement depression at these points. However, the depth from the topsoil to the bedrock surface varies between 2.5 to 37.75 m.
Open Access
Electrical Resistivity Investigation of the Bedrock Geometry of the Northern Sector of Kujama Priso...
Esther O Ocheja, Matoh D Dogara, Hyacinth O Aboh and Amina M Dawai
abstract View article PDF
An electrical resistivity investigation was carried to investigate the bedrock geometry of the northern part of Kujama Prisons Farm Kaduna using the Vertical Electrical Sounding (VES)
method. The study is aimed at obtaining information on the subsurface layering for future civil engineering works. The area covered was 200,000 sqm having five (5) profiles with six (6)
geophysical investigative points on each profile and separated 100m apart. Ohm-Mega resistivity meter was used for the Vertical Electrical Sounding (VES) and Thirty (30) points where established. To interpret the VES data, Res1D iterative software, Surfer 11 and Oasis Montaj software’s were used and it revealed three to five subsurface layers having Topsoil thickness between 0.3 − 2mand resistivity between 104 − 4824 Ωm also, the last layer considered as the weathered/fractured/fresh basement has an infinite thickness with resistivity
ranging from 45 – 10173 Ωm and the average overburden thickness of the area found to be 17.8m. The VES found fresh basement at points A3(6151 Ωm), A6(5089 Ωm), B3(1067Ωm), E5(10173 Ωm) and E6(1100 Ωm). From the study it is suggestive that the bedrock geometry has been irregularly configured over geological times due to effects of intense weathering. Therefore, the investigation revealed the study area may be considered for civil works of low bearing capacity.
Open Access
Shear Rheology and Molecular Properties of Biobased Adhesives Through Molecular Dynamics Simulation...
Agbogo U Victor, Dauda M Benjamin, Rajesh Haldar, Muktari Suleiman, Sunday P Simeon, and Sunmonu K Olufemi
abstract View article PDF
The study of shear rheology and molecular architecture through molecular dynamics simulation
of starch-based and gelatin-based adhesives formulated from Eleusine coracana, and cow hide
has been successfully achieved. This research has revealed that esterification of natural dextrins
with 20 % polyvinyl acetate (PVAc) will yield adhesives product with improved gel properties suitable for applications. Method of extraction, production of the adhesives by varying the
quantity of fatty acid ester and quality assessment was performed and 20% PVAc incorporation found to be suitable for application. The physical features of the macromolecular complexes
formed by the synergistic interaction of starch/gelatin and PVAc in the presence of
tetraethylamine (TEA) has been studied from the rheological point of view. On examining the impact of the molecular structure and electronic properties of the adhesive molecules on the
adhesive efficiency, quantum chemical calculations were carried out. Rheological analysis
shows the adhesives are consistent and the computed free energy obtained from molecular dynamics simulation reveals that the adhesive molecules are spontaneous, hence efficient.
Open Access
Effect of Beryllium and Magnesium Doped Stanene Single Layer on Structural and Electronic Propertie...
Alhassan Shuaibu, Yakubu A Tanko, Zainab Abdurrahman, Abdullahi Lawal, and Maharaz M Nasir
abstract View article PDF
Stanene is a quantum spin hall insulator and a favourable material for electronic and
optoelectronic devices. Density functional theory (DFT) calculations are performed to study the band gap opening in stanene by investigating the effect of beryllium and magnesium doped stanene single layer to study the electronic and structural properties in stanene. The electronic band energy of pure stanene without spin orbit coupling (SOC) appear to show no energy gap
at the Fermi level showing that stanene is a gapless material with Dirac cones at the K point and the band gap opens by a gap of 0.08 eV is opened at the K point. The electronic structure
of Be and Mg doped stanene shows that the Fermi level is shifted towards the valance band
edge when compared to pure stanene. We have considered 6.25, 12.5, 18.75 and 25% of both
Be and mg doping. The electronic structure of Be doped stanene show that the Fermi level is
shifted towards the valance band edge when compared to pure stanene. The Dirac point of
stanene locates at Γ shifted by 0.38 and 0.51eV for 6.25 and 12.5 %, an energy band gap of 0.27 and 0.50 eV were obtained above the Fermi level for 6.25 and 12.5% respectively. In the case of Mg, the bandgap remains slightly above the Fermi-level and amounts to 0.34 eV for 6.25 % and 0.43eV for 12.5 %, in the case of 18.75 and 25 % the Dirac cone disappear
completely, an energy gap of 0.28 eV and 0.60 eV were obtained above the Fermi level for
6.25 and 12.5% respectively, our findings show that the band gap of stanene open at 12.5%
doping concentration of both Be and Mg impurities. These obtained band-gap value seem to
be sufficient for use of alkaline earth metal doped stanene in optoelectronic and such
applications where stanene is incapacitate for its use to switch on/off devices.
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