Asian Journal of Physical and Chemical Sciences

First-Principles Prediction of Structural, Mechanical Stability, Thermodynamic Performance and Phonon Dispersion in an Emerging VRhTe and VRuSb Heusler Materials

M. E. Ishaje — 2026-03-20

This work investigated the structural, mechanical, thermodynamic, and phonon characteristics of Vanadium-Rhodium-Tellurium (VRhTe) and Vanadium-Ruthenium-Antimony (VRuSb) compounds by first-principles calculations grounded on density functional theory (DFT). The computations were performed under the generalised gradient approximation (GGA) utilising the Perdew–Burke–Ernzerhof (PBE) functional as processed in the Quantum ESPRESSO software package. The optimised structures indicated that both compounds crystallise in cubic Heusler-type (Fm–3m) symmetry and display thermodynamic stability, as proved by their negative formation energy and absence of structural distortions. The lattice parameter of VRuSb was slightly higher than that of VRhTe owing to the larger atomic radius of Sb. The results revealed that the Pugh's ratio for VRhTe is 11.94, whereas for VRuSb has the value 2.67, this demonstrates the compounds VRhTe, and VRuSb are ductile. The Poisson's ratio is 0.45 and 0.33 for VRhTe and VRuSb which is greater than the evalution value 0.30 (ⱱ > 0.30) signifies the metallic bonding characteristics ductility of the materials. This agree with the outcome of the Pugh‘s ratio. The thermal conductivity of a substance is been determined by the debye temperature. The materials suggest improved thermal conductivity at the debye temperature. Meanwhile, at high temperature the Dulong and Petit law agrees with the specific heat capacity of the heusler materials and adheres to the T³ rule as the temperature decreases. The heusler compounds reveals phonon dynamical stability as the frequencies and the phonon density of states are positives.

A Multi-scenario Analysis on Techno-economic Assessment of Groundnut Shell Gasification for Decentralised Power Generation in Senegal

Mbaye Gueye — 2026-03-24

Senegal’s rural electrification rate remains below 55%, with off-grid communities heavily dependent on diesel generation at costs of 190–220 FCFA/kWh. Groundnut shell, a lignocellulosic agricultural residue available at an estimated 700,000–900,000 tonnes annually across Senegal’s groundnut basin, represents a viable feedstock for decentralised gasification-based power generation. The primary objective of this study is to present a multi-scenario analysis of the first country-specific techno-economic assessment of a 500 kWₑ downdraft gasification system fuelled by groundnut shell for off-grid rural electrification in Senegal. The methodology involves a multi-scenario techno-economic modelling approach evaluating three development scenarios: conservative (S1), base case (S2), and optimistic (S3), which differ in capacity factor, feedstock cost, and electricity tariff. Technical performance parameters, feedstock characterisation data, and plant cost estimates were derived from literature proxies for analogous systems in comparable Sub-Saharan African contexts. The results indicate a levelised cost of electricity (LCOE) ranging from 98 to 142 FCFA/kWh, a net present value (NPV) of 48 to 187 million FCFA, and an internal rate of return (IRR) of 14.2% to 22.8% across scenarios, with a discounted payback period of 4.2 to 7.8 years. The sensitivity analysis confirms that feedstock cost is the dominant financial driver, with a ±30% variation inducing a ±18% change in IRR. The scientific contribution of this study lies in providing the first robust financial model for groundnut shell gasification tailored to the Senegalese context. Practically, at the base case LCOE of 112 FCFA/kWh, the technology demonstrates a decisive cost advantage over diesel generation, offering strong policy implications for its deployment under PERACCU-aligned rural electrification programmes and potential carbon credit monetisation under voluntary carbon market frameworks.

Preparation of Feedstock (Atmospheric Residue) for the Fluidized Catalytic Cracking (FCC) Process: A Case of the Zinder Refining Company

DOKA DAOURA Amadou — 2026-03-25

The Fluid Catalytic Cracking unit (FCC) is a key process that plays an important technical and economic role in the refining industry. Over the past years, there has been an increased interest in applying advanced process modelling and control that would lead to a significant economic benefit of FCC operation. This study presents a summary of the study on the preparation of a feedstock (atmospheric residue) from the RFCC unit (fluidized catalytic cracking process). The atmospheric residue, being the last cut drawn from the bottom of the atmospheric distillation column at a high boiling point > 350°C, may contain many impurities such as solids content, density, metal content, water content, residual carbon, etc. However, to ensure proper fluid catalytic cracking operation, it is necessary to characterize it to determine the appropriate type of preliminary treatment. Thus, the main objective of this study was to characterize the feedstock (atmospheric residue). In the environmental context, the characterization of the feedstock gave us an overall idea of its susceptibility to producing atmospheric pollutants such as SOX, COX, and NOX and allowed us to predict the severity of the cracking process in order to reduce the emission of these pollutants and limit coke formation. The characterization results, such as density at 15°C (925.52 kg/m³), residual carbon (6.842% mass), iron content (0.965 mg/kg), nickel content (24.905 mg/kg), vanadium content (0.385 mg/kg), lead content (0.09 mg/kg), copper content (0.06 mg/kg), calcium content (0.74 mg/kg), led to the conclusion that the FCC unit feedstock is ready to be sent to the FCC unit. The adverse impact on the cracking process, the environment, and the quality of the resulting products is minimal. The results also allowed us to conclude that the metal contents determined in the atmospheric residue studied have a low degree of contamination. This has earned Niger's atmospheric residue exceptional quality, making it much more competitive in international markets.

Assessment of Terrestrial Gamma Radiation and Radiological Health Risk in Oleh and Ozoro, Delta State, Nigeria

Oyovwevotu Oghenovo — 2026-03-26

This study presents an evaluation of terrestrial gamma radiation and associated radiological health risks across eight urban zones in Oleh and Ozoro, Delta State, Nigeria. Background ionizing radiation (BIR) and absorbed dose rate (ADR) measurements were conducted across four zones per town, yielding mean ADR values of 83.08 ± 10.63 nGyh⁻¹ in Oleh and 91.05 ± 12.54 nGyh⁻¹ in Ozoro. The corresponding annual effective dose equivalent (AEDE) values-0.103 ± 0.013 mSvy⁻¹ and 0.112 ± 0.016 mSvy⁻¹, respectively were significantly below the UNSCEAR global average of 0.41 mSvy⁻¹, indicating compliance with international radiological safety standards. Excess lifetime cancer risk (ELCR) estimates ranged from 0.332 ± 0.077 × 10⁻³ to 0.445 ± 0.074 × 10⁻³, with a pooled mean of 0.376 ± 0.055 × 10⁻³, marginally exceeding the UNSCEAR reference value but remaining within tolerable stochastic risk limits. Organ-specific dose analysis revealed elevated exposure in radiosensitive tissues, notably the testes and bone marrow. Statistical robustness was confirmed through Monte Carlo simulations, Bayesian inference, and Bootstrap resampling, all of which demonstrated convergence and internal consistency. The findings suggest moderate radiological exposure across the study area, with localized variations attributable to anthropogenic activity and lithologic composition. Routine monitoring and targeted public health interventions are recommended to sustain environmental safety.

Design and Implementation of High-Efficiency Transformerless Solar Inverter with Reduced Leakage Current

O. T. Oduola — 2026-03-26

The rapid growth of grid-connected photovoltaic (PV) systems has increased the demand for compact, high-efficiency, and cost-effective power conversion technologies. Transformerless solar inverters are increasingly used in modern PV systems because they eliminate bulky isolation transformers, resulting in higher efficiency, reduced size, lower cost, and improved power density. However, the absence of galvanic isolation introduces common-mode (CM) leakage current due to parasitic capacitance between the PV array and ground. This leakage current can cause electromagnetic interference (EMI), safety risks, and non-compliance with grid standards, making its reduction an important challenge in transformerless inverter design.This study presents the design, modelling, simulation, and experimental implementation of high-efficiency transformerless solar inverter with reduced leakage current for photovoltaic applications. The research focuses on developing an improved HERIC (Highly Efficient and Reliable Inverter Concept) topology capable of maintaining nearly constant common-mode voltage to suppress leakage current. Mathematical models of the PV array, DC–DC boost converter, and inverter stage were developed, and system performance was evaluated using MATLAB/Simulink simulations. To validate the proposed design, 1 kW laboratory prototype was constructed and experimentally tested. Results show that the inverter achieves efficiency above 98%, THD below 3%, and leakage current within safety limits, demonstrating improved performance for grid-connected PV systems.

Comprehensive Study of Substrate Materials for Rectangular Microstrip Patch Antenna At 3.5 GHz

E. T. Omogbe — 2026-03-26

5G communication demands compact, efficient antennas capable of operating in key bands like 3.5 GHz to support high data rates and reliable connectivity. Among various types, antenna design focuses on balancing performance, size, and integration for modern wireless applications. This study presents a comprehensive evaluation of ten different substrate materials for a rectangular microstrip patch antenna (RMPA) designed for 3.5 GHz 5G applications. The substrates investigated include FR-4, RO4730JXR, Teflon, E-glass, Taconic RF-35, Polystyrene, Form, Plexiglass, Fused Quartz, and TMM4. Key antenna performance parameters such as bandwidth, return loss, voltage standing wave ratio (VSWR), impedance matching, and radiation characteristics were analyzed using MATLAB R2024b-based electromagnetic modelling. Results indicate that the Plexiglass substrate achieved the best impedance matching with a return loss of −20.7726 dB and VSWR of 1.0043, while the Form substrate provided the widest bandwidth of 6.39 % with a good return loss of −17.84488 dB. The study emphasises the critical influence of substrate dielectric properties on antenna efficiency, bandwidth, and radiation behavior. Findings provide valuable guidance for material selection in sub-6 GHz 5G antenna design and contribute to the advancement of compact, high-performance wireless communication systems.

Effect of Purification on the Solubility of Natural Tahoua Phosphate in Perchloric Acid and Distilled Water

Abdoul Bari Idi Awali — 2026-03-26

The commercial phosphate from Tahoua is a sedimentary phosphate containing impurities that make phosphorus less available to plants. Furthermore, the industrial use of commercial phosphates containing non-essential metals increases the risk of environmental pollution. It is within this context that we undertook this study to enrich the commercial phosphates from Tahoua using particle size analysis and demagnetization techniques. These techniques improve its solubility and preserve its natural structure. After these treatments, we analyzed the commercial phosphate and the purified phosphate (obtained after treatment) using Brunuer-Emmett-Teller (BET) and scanning electron spectroscopy (SEM). The results obtained show that the specific surface area of the raw phosphate obtained is 487.250 m²/g and that of the purified phosphate is 695.864 m²/g. The micropore volume of the raw phosphate before treatment is 0.410 cc/g, and the volume of the phosphate after treatment without the use of any chemicals is 0.591 cc/g. This demonstrates an increase of 208.614 m²/g in the specific surface area and 0.181 cc/g in the micropore volume of the phosphates. Furthermore, the images obtained show a release of phosphate particles from the purified phosphate compared to the initial product. These results indicate an increase in the P₂O₅ content. This confirms a significant decrease in most oxides such as Al₂O₃, SiO₂, Fe₂O₃, MgO, MnO, etc. Finally, we dissolved the obtained products in perchloric acid and distilled water. The results obtained show an increase in the product's solubility. The dissolved phosphorus content, expressed as a percentage of P₂O₅ in the treated (purified) phosphate and in the marketable phosphate in perchloric acid and water, is 69.38% ; 34.21% and 17.44% ; 7.48%, respectively. These particle size analysis and magnetic separation techniques for the marketable phosphate have increased the P₂O₅ content in the solutions. This dissolved P₂O₅ content is more significant in soluble water. However, the purification effect of natural phosphate from Tahoua has direct importance for understanding and optimizing its solubility, a central element for its agronomic use.

Synthesis and Characterization of Engineered Nanobiochar for Enhanced Removal of Excess Fluoride in Water

Y. G. Ranga — 2026-03-27

Fluoride contamination in groundwater poses serious public health risks in many developing regions. This study reports the synthesis, characterization, and application of hydrochloric acid (HCl)-engineered corncob-derived nanobiochar for fluoride removal from aqueous solutions. Corncobs were pyrolyzed at 550 °C to produce biochar, mechanically milled to nanoscale dimensions, and chemically activated using 1M HCl. The engineered nanobiochar was characterized using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and Brunauer–Emmett–Teller (BET) surface area analysis. Batch adsorption experiments were conducted to evaluate the effects of adsorbent dosage, initial fluoride concentration, pH, and contact time. Optimal fluoride removal (80–90%) was achieved at a dosage of 0.8 g L⁻¹, initial fluoride concentration of 6 mg L⁻¹, pH 2, and contact time of 60 minutes. The enhanced performance was attributed to increased surface area, nanoscale porosity, and the introduction of oxygen-containing functional groups following HCl treatment. The results demonstrate that engineered corncob nanobiochar is a low-cost, sustainable, and effective adsorbent for fluoride removal, with strong potential for application in fluoride-endemic regions.

Influence of Fertilizers Made from Natural Phosphates of Tahoua on Millet Yield

Abdoul Bari Idi Awali — 2026-03-27

Recently, the interest in the potential of millets has been increased to contribute to sustainable and inclusive agricultural development, particularly in regions facing adverse impact of climate change and food insecurity. The productivity of millet-cereal cropping systems is threatened by soil degradation, which necessitates the application of nutrients that promote plant growth and development. The objective of this study is to evaluate the performance of different fertilizers—simple superphosphate (SSP), improved simple superphosphate (SSPA), and improved diammonium phosphate (DAPA)—made from Tahoua natural phosphate (PNT), as well as Tahoua natural phosphate powder, on millet yield. To determine the physicochemical parameters of the cultivated soil, it was noted that the soils studied have a silty-sandy texture and low levels of organic matter, total phosphorus, water-soluble phosphorus, and cation exchange capacity. After applying fertilizers to millet crops, the following grain and biomass yields were obtained: for grain, 520 kg/ha (PNT), 1355 kg/ha (DAPA), 1029 kg/ha (SSP), and 1589 kg/ha (SSPA); and for biomass, 2607 kg/ha (PNT), 6507 kg/ha (DAPA), 5989 kg/ha (SSP), and 7018 kg/ha (SSPA). However, the application of phosphorus-rich fertilizers showed a significant increase in millet yields. We observed that the yield was even higher with the application of the improved superphosphate fertilizer. This allows for better growth, more vigorous plants, and higher yields. It was observed that the highest yields were obtained with the application of improved superphosphate, while yields were lower with the application of natural phosphate from Tahoua. Therefore, improving the productivity of arable land for sustained and sustainable agricultural production is a major challenge in Niger.

Assessment of Physicochemical and Microbial Quality of Selected Wells in Macabalan, Cagayan de Oro City

Marwah S. Acub — 2026-03-30

This study employed a descriptive–comparative quantitative research design to assess the physicochemical and microbial quality of water from three selected community wells in Barangay Macabalan, Cagayan de Oro City, Philippines, and determine its suitability for domestic non-drinking uses such as bathing and laundry. The physicochemical parameters examined included pH, temperature, turbidity, and total dissolved solids (TDS), while microbial quality was evaluated through total coliform counts. The results were compared with the World Health Organization (WHO) guidelines for physicochemical parameters and the Department of Environment and Natural Resources (DENR) Class B standards for microbial content. Water samples were collected from three wells under sunny conditions during 2025–2026, with three sampling trials conducted per site. Samples were obtained using sterilized PET bottles after purging stagnant water, preserved in ice-filled coolers, and immediately transported to F.A.S.T. Laboratory for analysis. Physicochemical parameters were measured following standard laboratory protocols, while total coliform levels were determined using the Multiple Tube Fermentation Technique. Mean values were computed and compared with the established standards. Results showed that Site A (pH 6.75, temperature 20.03 °C, turbidity 2.57 NTU, TDS 665.33 mg/L) and Site B (pH 7.05, temperature 20.17 °C, turbidity 0.38 NTU, TDS 679 mg/L) complied with WHO recommended limits (pH 6.5–8.5, temperature ≤25 °C, turbidity ≤5 NTU, TDS ≤1000 mg/L). In contrast, Site C exceeded acceptable limits for turbidity (14.90 NTU) and TDS (1111.33 mg/L), although its pH (7.12) and temperature (21.13 °C) remained within the recommended range. Microbial analysis revealed extremely high total coliform counts in all wells: Site A (6,583 MPN/100 mL), Site B (35,667 MPN/100 mL), and Site C (27,667 MPN/100 mL), which significantly exceed the DENR limit of 200 MPN/100 mL. Despite generally acceptable physicochemical parameters in two wells, the severe bacterial contamination indicates that the water from all sites is unsafe for domestic use without treatment, highlighting the need for immediate remediation and continuous water quality monitoring.