Indian Journal of Pure & Applied Physics (IJPAP)

SAR and Temperature Rise in Human Tissues Under 5G Electromagnetic Wave Exposure: A Numerical Study

Amit Verma, vijay kumar, Amit Raj Singh — Wed, 25 Feb 2026 00:00:00 +0530

The rollout of fifth-generation (5G) wireless networks is driving the pervasive exposure to high-frequency electromagnetic fields, in the range (28–60 GHz), to a new scale. These are faster in carrying out data, but possible thermogenic effects on human tissue have raised concerns. This study aims to investigate the numerical modelling of channel-specific absorption rate and associated temperature increase in the human organs for 5G exposure based on Maxwell’s equations. Simulations were performed at different frequencies (28, 38, and 60 GHz) and exposure durations (6 and 20 min) in the visual part (skin and subcutaneous fat) and in/on the structures of the human head (eyes, brain, skull, ear canal, thyroid, wrist, chest). Results suggest that the SAR increases with frequency and has a maximum value in superficial tissues, whereas the temperature rise is strongly associated with both SAR and exposure time. The most sensitive tissues are the cornea, ear canal, which show temperature increases larger than 3 °C at 60 GHz for long exposure, even if
SAR values stay under internationally accepted safety levels. The results indicate that 5G EMW Waves at frequencies are of negligible risk to deep tissues despite a small elevation in temperature due to resonant absorption within the skin, with localized heating of the skin surface becoming of concern given ultra-close proximity exposure of long duration to devices operating at or near 5 G frequencies. The research highlights the need to incorporate thermal safety evaluations into existing exposure standards and proposes more looking into the long-term biological impacts of prolonged exposure to 5G.

An Investigation of the Structural, Morphological, and Dielectric, Properties of BiNi0.5Se0.5O3

PC Lalngilneia, Alok Shukla, Sushil Joshi — Wed, 25 Feb 2026 00:00:00 +0530

The preparation and comprehensive analysis of the BiNi0.5Se0.5O3 material, synthesized via a conventional solid-state route. Phase purity and crystallographic parameters were ascertained by powder X-ray diffraction, confirming the formation of the intended perovskite‐type structure. Microstructural examination by scanning electron microscopy revealed a uniformly polycrystalline morphology, with grain sizes predominantly in the 3 µm range. Elemental composition and stoichiometry were verified through energy-dispersive X-ray spectroscopy, which demonstrated the presence of Bi, Ni, Se, and O in ratios consistent with the nominal formula. Dielectric permittivity and electrical conductivity measurements were performed over a broad spectrum of temperatures and frequencies. Analysis of impedance spectra indicates a pronounced negative temperature coefficient of resistance, attributable to contributions from both grain interiors and grain-boundary regions. The frequency-dependent conductivity follows Jonscher’s universal power law, underscoring a hopping-dominated charge-transport mechanism. Collectively, these findings highlight BiNi0.5Se0.5O3 as a promising candidate for next generation electronic and energy‐storage applications.

Proposals for Ensuring the Validity of Force Measurement Measures

Seif M Osman, K M Khaled — Wed, 25 Feb 2026 00:00:00 +0530

Results validity is a cornerstone in structuring ISO/IEC 17025:2017. Results validity is the backbone for measurement quality. Validity of results may be ensured through different techniques, this article is directed to interested parties in force measurements to present the importance of ensuring the quality of results obtained from force proving instruments, force testing machines, and force standard machines to assure quality of life. Different proposals for ensuring the validity of results are given in detail. Each proposal is feathered by a measurement procedure, data analysis techniques, evaluation process, and acceptance criteria considering the associated risks. The proposed procedures are supportive methods in the force measurement field. They may be considered as an initiation to set a general guide in ensuring the quality and validity of force measurement results.

Multiscale Partial Differential Equation and Finite Element Modelling of Energy Storage Systems Integrating Thermodynamic and Electromagnetic Phenomena for Sustainable Solutions

Wed, 25 Feb 2026 00:00:00 +0530

Multiscale PDE-FEM models of energy storage systems combine electromagnetic phenomena with thermodynamic phenomena. They investigate very complicated systems with numerous parameters, beginning with those at the microstructure level of a material and extending to those at the device level. With this method, the simulation is quite detailed and demanding for the design of permanent, efficient energy storage solutions. Multiscale PDE-FEM models of energy storage aim to provide a high-end, multifaceted technique for precision yet uncomplicated simulation of the complex thermodynamic and electromagnetic processes at multiple scales and time scales. This aims to achieve high fidelity and computational ability in selecting design, performance, and durability of energy storage systems, which, through modeling, will facilitate further research into more flexible and durable energy solutions. The multiscale nature of energy storage systems involves different methods of modeling on various scales, which are the principal methods to be considered in multiscale PDE-FEM modeling. This consists of a continuum-scale model (macro-homogeneous, cell-packing level) of the behavior of the entire system, and a microstructure model (pore scale, atomistic) of a broad variety of material properties and events. The combination of these parameters with generalized multiscale finite methods (GMSFEM) and asymmetric multiscale methods (HMM) is necessary to guarantee a realistic representation of thermodynamic and electromagnetic processes, coupled on a strong and permanent basis. The PDE-FEM model with many scales has also reached significant energy storage. They made predictions of accurate coupled thermodynamic and electromagnetic behavior to enhance performance and design long-term designs with service life. These models have identified important mechanisms of failure at the microstructural scale by bridging scales, providing information to develop a more permanent and sustainable energy solution.

A Modified SRR Patch Antenna for Multiband Wireless Applications

Allin Joe D, Thiyagarajan K — Wed, 25 Feb 2026 00:00:00 +0530

Split Ring Resonator (SRR) antennas provide better electromagnetic characteristics and are used in various wireless applications. The designed antenna is developed on a cost effective FR4 substrate with dimensions of 35 x 35 mm² that features a simple and effective radiating geometry over it. This paper provides an overview of SRR antennas, with a focus on their design, mechanism, and ability to use in multiple frequency bands. The novelty of the designed SRR antennas is in their ability for manipulating the electromagnetic wave in the presence of resonators for the desired applications. The SRR antenna, with a focus on the use of slots in ground planes is used for improvement in frequency and bandwidth in wireless communication systems. Partial ground planes are used in the designed antenna for further improvement of radiation characteristics. The designed antenna is fabricated and measured for the validation of results. The measured results confirm that the designed antenna shall be utilized in worldwide interoperability for microwave access (WiMAX) communication, industrial, scientific, and medical radio band (ISM) communication, and in Sub-7 GHz fifth generation (5G) wireless communication.

Studies on Semi-Organic Single Crystal of L-Histidinium Phosphite (LHPI) for Optical, Thermal, Mechanical and NLO Applications

Indu, Mahak Vij, Meenakshi, Sonia — Wed, 25 Feb 2026 00:00:00 +0530

A semi-organic nonlinear optical material L- histidinium phosphite (LHPI) was grown as a single crystal using an economic slow evaporation solution growth technique. To determine the structural information i.e., the unit cell parameters, Single Crystal XRD analysis was performed and found that the compound has a monoclinic crystal System with P21 non centrosymmetric space group. Hirshfeld (HF) analysis and a 2-D fingerprint plot have been used to study the intermolecular interaction of the compound. Photoluminescence analysis revealed that the compound has green fluorescence emission. The specific heat of compound was calculated through Differential Scanning Calorimetry (DSC). The Laser damage threshold (LDT) of LHPI is 1.13 and 0.78 GW cm-2 for one and 10 pulse/second respectively. The frequency conversion property of this compound was studied through the Kurtz- Perry powder technique (SHG) and Z-Scan technique. Microhardness studies revealed that LHPI is a hard material. Through Shock Damage Threshold (SDT), the stability of the material against shock wave was assessed, which indicates that no damage appears up to the 5th shock.

Solar and Interplanetary Sources of Major Geomagnetic Storms: Case Studies from Solar Cycle 24 (2008–2019)

Wed, 25 Feb 2026 00:00:00 +0530

Geomagnetic storms represent significant space weather phenomena with the potential to disrupt critical technological infrastructure, including communication satellites, navigation systems, and terrestrial power grids. This study presents a descriptive analysis of the four most geo-effective geomagnetic storms of Solar Cycle 24 (2008–2019), a cycle noted for its unusually low activity. The heliospheric drivers of these events are investigated by correlating solar and interplanetary data with the disturbance storm time (Dst) index. The analysed storms, including the notable "St. Patrick's Day" storm of 17 March 2015, as well as events on 23 June 2015, 20 December 2015, and 26 August 2018, were selected based on their intensity (Dst ≤ -150 nT). Our analysis reveals that the primary drivers were interplanetary coronal mass ejections (ICMEs) and their preceding sheath regions. A key insight from this study is the diversity of the storm drivers; major storms were initiated not only by fast CMEs but also by slower CMEs with highly geo-effective magnetic field configurations. Specifically, the prolonged duration of a strong southward interplanetary magnetic field component (Bz) was identified as the crucial factor determining the magnitude of each storm, underscoring that forecasting models must prioritise the analysis of in-transit CME magnetic structure over initial kinematics to improve the prediction of severe storm impacts.

Synthesis of ZnO–TiO₂ Hybrid Nanoparticles via Plasma Jet Technique for Enhanced Photocatalytic and Antibacterial Applications

Tamara A Hameed, Al-Behadili Faisal Raheem, Ali Q Tuama, Rajaa Obayes Abdulsada — Wed, 25 Feb 2026 00:00:00 +0530

ZnO, TiO₂, and ZnO–TiO₂ hybrid nanostructures were synthesized using an atmospheric-pressure plasma jet as a fast and solvent-free approach. Optical emission spectroscopy confirmed the formation of a stable oxygen plasma with an electron temperature of approximately 0.83 eV and an electron density of ~1.7 × 10¹⁷ cm⁻³. XRD analysis revealed well-defined crystalline phases with average crystallite sizes of about 12 nm for ZnO, 16 nm for TiO₂, and 14 nm for the ZnO–TiO₂ hybrid. Optical studies showed a significant band gap reduction to 2.68 eV for the hybrid compared with the individual oxides. The ZnO–TiO₂ hybrid exhibited superior photocatalytic activity toward methylene blue degradation under natural sunlight, achieving a degradation efficiency of 94.26% with a pseudo-first-order rate constant of 0.036 min⁻¹. Antibacterial evaluation demonstrated enhanced inhibition zone diameters of 29 mm against Staphylococcus aureus and 25 mm against Escherichia coli. The improved performance is attributed to efficient interfacial charge separation and enhanced reactive oxygen species generation at the ZnO–TiO₂ heterojunction.

Modelling and Performance Optimization of Orthogonal MIMO Dielectric Resonator Antenna with Defected Ground Structure

Amsaveni A, Bharathi M, Megavarshini R — Wed, 25 Feb 2026 00:00:00 +0530

This research introduces a high-efficiency multiband MIMO antenna system based on Dielectric Resonator Antennas (DRAs) integrated with a Defected Ground Structure (DGS). Designed to operate at 5.6 GHz, 7.3 GHz, and 8.9 GHz, the antenna supports various modern wireless applications, including Wi-Fi, 5G New Radio (NR), Internet of Things (IoT), Vehicle-to-Everything (V2X) communication, and radar technologies. The antenna is built on an FR4 substrate and employs two pentagonal alumina (Al₂O₃) resonators, which contribute to its high radiation efficiency (~90 %). A DGS composed of rectangular slots is incorporated to minimize surface wave propagation and significantly enhance isolation between elements (|S₁₂| < -35 dB). Compared to conventional MIMO antenna types such as microstrip patches, slot-based, and metasurface configurations the proposed design offers superior isolation and gain (~5 dBi). Additionally, the orthogonal positioning of the resonating elements effectively reduces mutual coupling, reinforcing its suitability for high-performance, next generation wireless systems.