Asian Journal of Research and Reviews in Physics

Recent Advances in Carbon Doped ZnO Thin Films Correlating Structural Evolution with Optical Performance

Zainab Hussein Mutar — 2026-07-09

Carbon-doped zinc oxide (ZnO) thin films have garnered significant attention in recent years due to their ability to simultaneously modify the structural, electronic, and optical properties of zinc oxide. The introduction of carbon leads to the development of numerous defect configurations within the ZnO lattice, as well as significant changes in crystallinity, lattice stress, defect density, and electronic band structure. These modifications are crucial for enhancing the optical properties of ZnO thin films and for their application in high-tech optoelectronic devices. This review aims to provide a detailed account of the latest advancements in carbon-doped ZnO thin films and the relationship between structural changes and optical properties. It discusses different carbon insertion modes (substitutional and interstitial) and outlines the main techniques for film preparation. The review also provides a detailed analysis of the effects of carbon doping on crystal structure, crystal size, lattice parameters, microstress, and defect generation. Furthermore, the optical transmittance and absorption properties, optical bandgap geometry, refractive index, and absorption coefficient of the embedded carbon were investigated. A literature review revealed that carbon doping is an effective method for modifying the electronic structure of zinc oxide (ZnO) by introducing defective states and adjusting the bandgap, thereby enhancing visible light absorption and photovoltaic functions. These achievements have paved the way for the application of ZnO thin films in diverse fields, including photodetectors, solar cells, gas sensors, transparent electronics, and photocatalytic systems. Finally, some remaining challenges and future research directions were highlighted, emphasizing the importance of precise defect control, improved synthesis processes, and advanced characterization techniques for developing next-generation ZnO technologies.

Role of Laser Pulse Shape Asymmetry in Electron Acceleration from Underdense Plasmas

Deep Kumar Kuri — 2026-07-08

Temporal asymmetry in the shape of a linearly polarised laser pulse can influence electron acceleration during interaction with underdense plasmas. This study numerically investigates electron acceleration for Gaussian, positive-skew and negative-skew laser pulses using a one-dimensional fluid model. The positive-skew pulse is characterised by a sharp rise and slow fall, whereas the negative-skew pulse has a slow rise and sharp fall. The model solves Maxwell equations, the electron continuity equation and the electron momentum equations to compare laser propagation, wakefield generation, electron energy gain and harmonic production under different pulse-shape conditions. The results show that the positive-skew pulse generates a strong intensity gradient at the laser front, producing a strong ponderomotive force and an immediate increase in electron energy. However, the negative-skew pulse allows electron oscillations to persist for a longer duration near the laser pulse, resulting in a stronger wakefield of approximately 650 GV/m and the highest electron energy gain of approximately 0.25 MeV. During propagation through the plasma, the laser pulse splits into harmonic components, and odd harmonics up to the 29th order are observed. No substantial difference in spectral intensity is found among the Gaussian, positive-skew and negative-skew cases. These findings indicate that temporal pulse asymmetry can influence wakefield evolution and electron acceleration in underdense plasmas.

Heat and Mass Transfer on MHD Blood Flow with Casson Fluid and Slip Effect Past a Porous Wounded Surface using Power Series Solution and Undetermined Coefficient Method on Perturbation Technique

Ekakitie Omamoke — 2026-07-09

This study presents an analytical investigation of heat and mass transfer in magnetohydrodynamic (MHD) blood flow modelled as a Casson fluid past a porous wounded surface under slip, suction/injection and chemical reaction effects. The governing dimensional equations for momentum, energy and concentration transport were transformed into non-dimensional form using appropriate similarity variables and physical parameters. A perturbation procedure was applied to reduce the coupled system, and approximate analytical expressions for velocity, temperature and concentration distributions were derived using the method of undetermined coefficients and a power series solution. The effects of the magnetic field parameter, Casson fluid parameter, suction/injection, porosity, Prandtl number, Schmidt number, heat source parameter, chemical reaction rate, thermal Grashof number, solutal Grashof number and slip length were examined graphically and through transport quantities. The results indicate that the magnetic field parameter, Schmidt number, porosity, chemical reaction parameter, heat source parameter, Casson parameter and suction reduce the velocity profile, whereas the Prandtl number, thermal Grashof number, solutal Grashof number and slip length enhance it within the model assumptions. Temperature decreases with suction and Prandtl number and increases with the heat source parameter. Concentration decreases with suction, chemical reaction parameter and Schmidt number. Skin friction, Nusselt number and Sherwood number describe the sensitivity of momentum, heat and mass transport to the governing parameters. The study provides a theoretical framework for coupled MHD, thermal and concentration transport in Casson blood flow near a porous wounded surface without experimental validation.

Optimizing Real-time Signal Processing in Particle Physics Using Machine Learning Algorithms for High-energy Particle Detection

Sujata Nema — 2026-07-10

Real-time signal processing is essential in high-energy particle physics, where detector systems produce large volumes of waveform data under strict latency and storage constraints. This study examines the use of machine learning algorithms for waveform-based event classification in high-energy particle detection, with emphasis on signal-background discrimination and trigger-oriented processing. Detector responses are represented as one-dimensional time-series waveforms that encode temporal structure, amplitude variation, noise components and non-linear behaviour. The manuscript evaluates the relevance of convolutional neural networks, long short-term memory networks and a hybrid CNN-LSTM approach for extracting discriminative features from these complex signals. The analysed dataset contains labelled signal and background events, allowing supervised classification after preprocessing steps such as normalisation, filtering, outlier treatment and interpolation to improve signal quality and model robustness. The proposed CNN-LSTM model correctly identified 116 of 120 signal events and 115 of 120 background events in the test set, with a reported accuracy of 96.25%. Comparative performance indicates that the hybrid model outperformed decision tree, random forest, support vector machine, CNN and LSTM models in the reported analysis. These findings suggest that deep learning can support efficient waveform classification and may assist real-time trigger decisions when integrated with suitable low-latency hardware frameworks. However, further validation using larger benchmark datasets, transparent training protocols, hardware-based latency assessments across different event classes, noise levels, and realistic detector operating conditions is required before operational implementation in particle-physics experiments.

Preparation, Characterization and Holographic Interferometric Study of Electrodeposited CuS, CuSe and CuTe Thin Films

V. P. Malekar — 2026-07-10

Holography is an advanced optical technique that enables three-dimensional recording and reconstruction of information using coherent electromagnetic waves. Among its applications, holographic interferometry is a useful non-destructive method for evaluating surface deformation, residual stress and the mechanical behaviour of thin films through the analysis of interference fringe patterns. In the present study, double-exposure holographic interferometry, coupled with mathematical modelling, was used to determine the stress, mass, fringe width and thickness of electrodeposited thin films. Copper chalcogenide thin films were synthesised by electrodeposition under varying deposition times and electrolyte normalities to investigate their influence on film growth, material deposition and substrate deformation. The study was carried out systematically to understand the relationship between deposition parameters and the resulting physical properties of the films. The experimental results showed that, with increasing deposition time, the number of fringes increased from 3 to 8, 4 to 10 and 3 to 10; film thickness increased from 0.949 to 2.531, 1.265 to 3.164 and 0.942 to 3.164 μm; deposited mass increased from 1.865 to 4.975, 3.184 to 7.959 and 2.830 to 9.435 mg; substrate stress decreased from 0.101 to 0.037, 0.075 to 0.030 and 0.101 to 0.030 dyne/cm2; and fringe width decreased from 0.105 to 0.040, 0.314 to 0.051 and 0.127 to 0.045 cm for copper sulphide, copper selenide and copper telluride thin films, respectively. These results indicate enhanced film growth and reduced deformation effects at longer deposition durations. The structural, optical and surface characteristics of the deposited thin films were analysed using X-ray diffraction (XRD), ultraviolet-visible optical absorption spectroscopy and contact angle measurements. These characterisation techniques provided information on the crystallinity, optical behaviour and wettability of the synthesised films.

Assessment of Electromagnetic Radiation Emissions from Mobile Base Stations in Gwarinpa, Federal Capital Territory (FCT) Abuja, Nigeria

Samson Dauda Yusuf — 2026-07-15

This study assessed radiofrequency electromagnetic radiation emissions from 13 selected mobile base stations in Gwarinpa, Federal Capital Territory, Abuja, Nigeria. Electric field strength, magnetic field strength, and power density were measured to determine whether the emissions complied with international public-exposure reference levels. A calibrated TENMARS radiofrequency electromagnetic field meter, covering 10 MHz to 8 GHz, was used for the field measurements. Measurements were obtained under normal operating conditions at distances of 5, 50, 100, 150, 200, 250, and 300 m from each base station. The measured values varied among stations and across distances. The maximum electric field strength was 12,911 mV/m, equivalent to 12.911 V/m; the maximum magnetic field strength was 34,250 µA/m, equivalent to 0.03425 A/m; and the maximum power density was 442,000 µW/m², equivalent to 0.442 W/m². Each maximum value was below the applicable International Commission on Non-Ionizing Radiation Protection reference levels for public exposure within the relevant radiofrequency range. Higher measurements were generally observed at intermediate distances rather than directly beneath the antenna structures, indicating spatial variation among the assessed locations. Within the measurement period and sampled locations, the mobile base stations complied with the international exposure limits used for comparison. The findings support periodic monitoring, appropriate siting, and clear public communication as telecommunications infrastructure expands in residential areas. The study provides site-specific baseline data for regulatory surveillance and future radiofrequency exposure assessments in Gwarinpa.

Influence of Molybdenum (Mo) Doping on the Structural, Optical, and Electrical Characteristics of Zirconium Oxide (ZrO2) Nanostructures for Optoelectronics and Photovoltaic Applications

Samuel Oghenemega Shaka — 2026-07-16

This study investigated the influence of molybdenum (Mo) doping on the structural, optical, morphological, and electrical properties of zirconium oxide (ZrO₂) nanostructured thin films for optoelectronic and photovoltaic applications. Mo-doped ZrO₂ thin films were deposited on fluorine-doped tin oxide (FTO) substrates using the Electrostatic Spray Deposition (ESD) technique. The precursor solution was prepared from zirconium (IV) oxychloride octahydrate (ZrOCl₂·8H₂O), ammonium molybdate ((NH₄)₆Mo₇O₂₄·4H₂O), sodium hydroxide (NaOH), and distilled water. Deposition voltages of 10, 12, and 14 V were used for the doped films, while pristine ZrO₂ served as the control. Increasing the deposition voltage enhanced droplet atomization, charge density, and spray stability, resulting in improved substrate wetting and more uniform film formation. X-ray diffraction (XRD) analysis showed that pristine ZrO₂ exhibited broad diffraction peaks indicative of low crystallinity, whereas Mo doping enhanced crystallinity through sharper and more intense peaks. The crystallite size decreased from 1.47 nm for pristine ZrO₂ to 1.19 nm for the film deposited at 14 V, while the dislocation density increased from 1.36 lines/m² to 2.29 lines/m². SEM images revealed a transformation from agglomerated clove-like structures to smoother, compact, and homogeneous nanostructures, and EDX confirmed successful Mo incorporation without significant impurities. Optical studies showed increased absorbance and reduced transmittance with Mo doping. The optical band gap decreased from 2.50 eV for pristine ZrO₂ to 2.42 eV, 2.41 eV, and 2.35 eV for films deposited at 10 V, 12 V, and 14 V, respectively, indicating enhanced visible-light absorption. Refractive index, extinction coefficient, optical conductivity, and dielectric constants also increased. Film thickness increased from 105.15 nm to 129.01 nm, while resistivity rose slightly from 5.83 × 10⁻⁷ Ω·m to 6.39 × 10⁻⁷ Ω·m and conductivity decreased from 1.72 × 10⁻¹⁰ S/m to 1.56 × 10⁻¹⁰ S/m. These findings indicate the potential of ZrO₂/Mo thin films for solar cells, photodetectors, photocatalysis, optical coatings, and other optoelectronic applications.

Characterisation and Mitigation of Multipath Effects on Satellite Positioning Accuracy: A Case Study of Ladoke Akintola University of Technology, (LAUTECH), Ogbomoso, Nigeria

Oluwadara Abosede Oyelowo — 2026-07-23

The Global Navigation Satellite System (GNSS) was developed to offer precise, accurate, and reliable positioning for various scientific and real-time applications, including everyday communication, navigation, disaster management, and security. Despite the increasing demand to enhance GNSS accuracy in urban canyons, such as on campuses, previous research has rarely tackled the challenge of mitigating multipath effects using raw observation dual-frequency data logs from a compact, low-cost GNSS receiver, especially on Nigerian campuses. A u-blox ZED-F9P GNSS receiver was used to log data continuously for thirty days in dual-frequency GPS-only, GLONASS-only, and GPS+GLONASS hybrid modes at a 4Hz sampling rate across fifteen reference coordinates (RCs) at Ladoke Akintola University of Technology, Ogbomoso, Nigeria. In this study, performance metrics such as carrier-to-noise ratio (C/No), Precise Point Positioning (PPP), Two-Distance Root Mean Square (2DRMS), Circle of Error Probable (CEP), Spherical Error Probable (SEP), Mean Radial Spherical Error (MRSE), Standard Deviation Error (S.D), Number of Satellites Visible (NSV), and Dilution of Precision (DOP) were used to evaluate the position accuracy of the processed data. The results showed that LAUTECH Hall and Chapel RC revealed less than 0.006m horizontal and 0.029m vertical accuracy in PPP when operating in GPS+GLONASS hybrid mode, indicating the best position accuracy for GNSS PPP among the RCs. Further analysis indicates that the LAUTECH Hall, Mosque, and Chapel RC have a mean C/No higher than 40 dB Hz, a maximum NSV of 10, and a low GDOP of 2.5, PDOP of 2.2, HDOP of 1.0, and VDOP of 1.9. It was noticed that the GPS+GLONASS hybrid mode adopted in this study mitigates multipath effects with specific positioning accuracy of less than 0.005m at about three RCs in LAUTECH.

Design, Simulation and Implementation of a Microcontroller Based Automatic Car Parking System

Samson Dauda Yusuf — 2026-07-24

Rapid growth in vehicle numbers has increased pressure on limited parking facilities, particularly in commercial areas and public offices. This study designed, simulated, constructed and evaluated a microcontroller-based automatic car parking control system with automatic gate shutdown. The system was simulated in Proteus using an ATmega328 microcontroller programmed in the Arduino language. Its principal units comprised two TCRT5000 infrared detectors for vehicle detection, a microcontroller, a servo motor, an LCD and a DC power supply. A prototype was constructed and tested to determine its sensitivity and accuracy in detecting vehicles entering and leaving the parking area and in controlling the entrance gate according to the recorded vehicle count. For vehicles entering the parking area, the system achieved a sensitivity of 98.40% and an accuracy of 94.42%. For vehicles leaving, the sensitivity and accuracy were 99.30% and 94.38%, respectively. The overall sensitivity was 98.85%, while the overall accuracy was 94.40%. These results indicate that the prototype detected and controlled most vehicle movements under the experimental conditions, although a small proportion of events was not correctly controlled. The system also displayed the parking status and operated the gate according to vehicle movement and available capacity. The developed prototype may support automated parking control in small parking facilities and reduce the manual effort and time associated with managing vehicle entry and exit.

Degree-Based Topological Descriptors and Physicochemical Structure–Property Trends in Oligothiophene Derivatives

Mohammed Alsharafi — 2026-07-24

This study presents a graph-theoretical and descriptive structure–property analysis of the linear \(\alpha\)-linked oligothiophenes
bithiophene, terthiophene, quaterthiophene, sexithiophene, and octithiophene. From the common edge partition of their
hydrogen-suppressed molecular graphs, explicit closed forms are derived for fourteen degree-based descriptors: the first and second Zagreb, forgotten, Yemen, first and second hyper-Zagreb, three redefined Zagreb, Randi´c, Sombor, Yemen–Sombor, geometric–arithmetic, and atom–bond connectivity indices. Numerical values are obtained for all five molecules. Ten physicochemical endpoints reported in PubChem—polar surface area, molecular weight, complexity, XLogP3-AA, heavy-atom count, boiling point, enthalpy of vaporization, flash point, molar refractivity, and molar volume—are analyzed using descriptive linear regression. Every considered index is an affine function of oligomer length; therefore, the fourteen univariate regressions have identical fitted values and goodness-of-fit statistics for a fixed endpoint, although their slopes and intercepts differ. To avoid redundant reporting, the main text provides a compact endpoint-level summary and one representative index model, while all 140 descriptor–endpoint equations are supplied in the supplementary material. The models describe trends within this five-member homologous series and are not presented as externally validated predictive QSPR models.

Magneto-Thermal Transport in Iron Oxide Nanofluid Flow through a Chemically Reactive Porous Channel

Nwabuzor, Peter Onyelukachukwu — 2026-07-29

This study examines magneto-thermal transport in an electrically conducting iron oxide (Fe₃O₄)–water nanofluid flowing through a chemically reactive porous rectangular channel under a transverse magnetic field and thermal radiation. The mathematical model couples the momentum, energy, and species-concentration equations with constitutive relations for effective viscosity and thermal conductivity, a velocity-dependent electrical conductivity model, and an optically thin radiation approximation. The governing equations are non-dimensionalised using the Buckingham π theorem and relevant hydrodynamic parameters. The resulting coupled system is solved analytically by the Laplace transform to obtain closed-form expressions for the velocity, temperature, and concentration fields. The analysis evaluates the effects of nanoparticle volume fraction, Prandtl number, Schmidt number, thermal and concentration Grashof numbers, radiation, chemical reaction, Reynolds number, magnetic field, and electrical conductivity. Increasing nanoparticle volume fraction raises the temperature and concentration distributions but reduces velocity because of increased viscous resistance. Higher Prandtl and Schmidt numbers restrict thermal and species diffusion, respectively. Chemical reaction reduces concentration, while increasing magnetic-field strength and electrical conductivity suppresses fluid motion through Lorentz-force damping. Radiation primarily modifies the temperature field and has only a limited direct effect on velocity under the present assumptions. These findings clarify the coupled roles of magnetic, thermal, and reactive parameters in porous ferro-nanofluid transport and may support the design of thermal systems requiring controlled heat and mass transfer.

Degree-Based Topological Entropies of Polythiophene and Bipolaron Networks: Exact Formulas and Descriptor Redundancy

Mohammed Alsharafi — 2026-07-31

Degree-based graph entropies quantify structural heterogeneity in molecular networks. However, a unified entropy treatment
of polythiophene and its bipolaron counterpart, together with a direct assessment of descriptor redundancy, is still lacking.
This study therefore derives closed-form expressions for fourteen degree-based topological indices and their Shannon-type
entropies for polythiophene PL_P and the bipolaron network BIPL_P, and examines whether the resulting entropy measures provide distinct structural information. The descriptors considered are the Zagreb, hyper-Zagreb, forgotten, Yemen, redefined Zagreb, Randi´c, Sombor, Yemen–Sombor, general sum-connectivity, geometric–arithmetic, and atom–bond connectivity indices. The edge partitions are determined from the degrees of adjacent vertices and then used to obtain formulas for all admissible values of p. Numerical values and plots show how the indices and entropies vary with p. The entropy sequences are highly correlated over the examined ranges, indicating that several descriptors carry nearly the same information. The formulas give exact structural invariants for the two network families and help identify a smaller, non-redundant descriptor set for later structure–property studies.