This paper presents the comparison performance of an eight channels of DWDM optical transmission system proposed for various data rates 10Gbs, 20Gbs, 30Gbs, and 40 Gbs respectively. The findings of this study are based on an analytical approach and numerical simulations conducted using OptiSystem software version.7. In the first study of simulation, a fixed optical transmission length at 100 km of Single Mode Fiber (SMF) and 20.93 km of dispersion compensation fiber (DCF) used as post-compensation configuration has been considered. And in the second study of simulation, the optical transmission distance has been varied from 100 km to 220 km respectively. It is known, the main factors limiting to transmit high speed data and aim to reached long-haul distance are the chromatic dispersion, attenuation, and non-linearities. To overcome these impairments many studies suggested techniques namely DCF and fiber bragg grating (FBG). In this work, these dispersion compensation techniques are combined in a serial configuration and treated as a single hybrid DCF-FBG compensation module, implemented in a post-compensation scheme after the transmission fiber. Furthermore, integrated the Erbium doped fiber amplifiers (EDFA) in order to upgrade optical system capacity to reach transmission distance up to 200 km and transmission data rate up to 40 Gb/s. Eye diagram, maximum signal quality factor (Q), minimum bit error rate (BER) are the major interesting performance parameters for measuring the efficiency of the DWDM system proposed using two dispersion compensation configurations: a DCF-only module and a hybrid serial DCF-FBG module. The results indicate a significant enhancement in system performance when the hybrid DCF-FBG module is utilized, compared with the DCF-only module, for the four simulated data rates. For a data rate of 40 Gb/s over 100 km of SMF, the obtained Q-factor reaches 16.97 (BER = 5.955 x 10-65) when the hybrid DCF-FBG scheme is employed, compared with a Q-factor of 14.76 (BER = 1.191 x 10-49) achieved using the conventional DCF technique. The optimized transmission distance for the 40 Gb/s signal is found to be 170 km when the hybrid DCF-FBG compensation approach is applied. Furthermore, in comparison with previously reported studies, the results obtained from the two proposed optical system designs clearly outperform those reported in earlier published works, as will be demonstrated in the simulation results section.
This paper presents the theoretical investigation, finite-element simulation, and design optimization of a MetamaterialEnhanced THz Detector for Room-Temperature Terahertz Imaging. The proposed detector consists of a suspended MEMS platform incorporating a 3 & times;3 array of square-patch MMA unit cells optimized for imaging at 1 THz. Electromagnetic simulations demonstrate polarization-insensitive absorbance exceeding 80 % at the target frequency, with stable performance for incidence angles up to 45 degrees. The suspended platform is supported by Au-SiO2 bimorph actuators engineered to balance sensitivity and response speed. An analytical model is developed to investigate and identify a trade-off among different performance parameters. For an optimized platform area of 230 & micro;m & times; 230 & micro;m and a dielectric thickness of 1.5 & micro;m, the detector achieves a designed time constant of 300 ms with 253 & micro;m-long bimorph actuators and 0.8 fractional Au coverage. Finite-element simulations in CoventorWare (R) validate the analytical predictions, yielding a thermomechanical sensitivity of 0.063 degrees/K and a responsivity of 0.056 degrees/& micro;W, with a temperature rise of 1.25 K under 1 & micro;W incident power. Noise analysis indicates that temperature-fluctuation noise dominates, yielding a noise-equivalent power (NEP) of 2 pW at 295 K. The proposed analytical design methodology provides a method for developing high-sensitivity, room-temperature detectors suitable for THz imaging.
Biometric authentication plays a vital role in protecting sensitive data; however, traditional mechanisms such as passwords and tokens remain susceptible to loss, theft, and misuse. Although unimodal biometric systems are limited by poor data quality and higher error rates, multimodal biometric approaches offer improved robustness and reliability. This work proposes a novel secure multimodal biometric fusion framework that integrates facial and iris recognition using Convolutional Neural Networks (CNNs) combined with variance-based discriminative feature selection and cryptographic template protection. Unlike conventional fusion-based systems that treat security as a post-processing step, the pro-posed framework embeds security directly into the fusion pipeline, ensuring template irreversibility, unlink ability, and resistance to cross-matching attacks without compromising recognition performance. Multiple fusion strategies were systematically evaluated, including feature-level, decision-level, score-level, and a newly designed enhanced score-level fusion mechanism. Experimental results demonstrate that the proposed fusion strategy consistently outperforms existing methods, achieving an accuracy of 97.5 % and a low Equal Error Rate (EER) of 0.25%, which exceeds state-of-the-art multimodal biometric systems. Extensive experiments conducted on the labelled Faces in the Wild (LFW) and Chinese Academy of Sciences Institute of Automation (CASIA-iris) benchmark datasets validate the effectiveness, security, and practical applicability of the proposed framework for high-security and real world authentication scenarios, such as smart infrastructure and access-controlled environments.
In this study, the influence of substrate temperature and post-deposition annealing on the structural, electrical, and optical properties of indium tin oxide (ITO) thin films has been systematically investigated. ITO films were deposited using an RF magnetron sputtering system at varying substrate temperatures. The as-deposited films revealed that higher substrate temperatures lead to enhanced crystallinity, improved electrical conductivity, and greater optical transparency. Furthermore, post-deposition annealing of room-temperature-grown films resulted in an increase in visible transmittance from 77 % to 82 %, accompanied by a rise in sheet resistance from 30 to 70 Omega/sq. Comparative analysis indicated that films directly deposited at elevated substrate temperatures exhibit superior performance, achieving visible transparency of approximately 85 % and a lower sheet resistance of around 33 Omega/sq, outperforming their annealed counterparts.
In this paper, the optimization of an ultra-wideband optimal gain parasitic circularly polarized patch antenna for C-Band, X-Band, and Ku-Band applications has been presented. The proposed geometry of the antenna is designed using a negative mutual coupling approach and parasitic array techniques. The geometrical structure has been configured by a ground plane, driven element, and top layer U- slot director. The greenhouse analysis is being used for the calculation of total inductance and mutual inductance of the geometries. The gap coupling and negative mutual approaches have been used for enhancing the gain and impedance bandwidth of the designed antenna. The novel U-shaped directors have been used to improve the radiation characteristics of the antenna. The optimization of the antenna is discussed in five sections. The mathematical modeling of inductance and mutual inductance has been done for an appropriate solution. After all optimizations, the optimum antenna design has been found, providing an operating impedance bandwidth and optimal gain from 5. 8 GHz to 18.15 GHz. The proposed parasitic array antenna has been designed with appropriate dimensions and can be used for XBand, Ku-Band, and C-Band wireless communication. The simulated antenna has been fabricated and validated experimentally.
This study presents a bimetallic surface plasmon resonance (SPR) sensor for the non-invasive detection of volatile organic compounds (VOCs) in human breath, targeting early diagnosis of liver and pulmonary diseases. The proposed multilayer structure consists of a NaF prism, Ag/Au bilayer, Ge2Sb2Te5 (GST) phase-change material, black phosphorus (BP) layers, and a sensing medium. Finite element simulations using COMSOL Multiphysics were conducted to evaluate angular reflectance characteristics and optimize layer thicknesses and BP stacking. Sensor performance was assessed through resonance angle shifts corresponding to variations in VOC concentration. The optimized configuration, comprising amorphous GST and 18 BP layers, demonstrated superior sensitivity due to enhanced electromagnetic interaction at the sensing interface. The sensor achieved refractive index sensitivities of 1500 RIU-1 for lung disease biomarkers and 163.630 RIU-1 for liver-related biomarkers. These results highlight the potential of the proposed SPR design for accurate, breath-based biomedical diagnostics.
Multilevel inverters (MLIs) must be accurately modelled and predicted to enhance output quality, minimize total harmonic distortion (THD). The three DC voltage sources are set up in the following ratio like 1:2:4 to allow the inverter to produce different voltage levels using various switching combinations. By controlling the above seven switches and three diodes properly, the above sources will be combined in such a way that a stepped output waveform having better resolution and lower harmonics will be achieved. This configuration improves the quality and efficiency of the output for the supply of an R-L load, and ensure efficient operation in applications of renewable energy. In this study, the ability of three advanced machine learning algorithms namely Artificial Neural Network (ANN), Random Forest (RF) and Extreme Gradient Boosting (XGBOOST) to predict MLI output under different operating conditions is investigated. Such kinds of data-driven modelling models deal with the characteristics of inverter systems, namely the non-linear and dynamic system behaviour. A comparative analysis, based on the accuracy of prediction and the performance of the generalization of the results, shows that while ANN and Random Forest algorithms show an acceptable level of accuracy, the XGBOOST algorithm shows to be better at performing than both models. The following ANN model R2= 0.9711 was obtained, which is 97 % of the variation of the output, during the training of the neural network. Random Forest model showed better generalization with the R2=0.9977 (training) and 0.9874 (testing), which is a good predictive capability. However, XGBOOST showed better performance (R2=0.9999 during training, R2=0.9830 during testing indicating close to perfect learning of the training data and excellent generalization on unseen data). Overall, the results present a good confirmation of the suitability of XGBOOST as the most accurate and robust model with computational efficiency to predict the output voltage and harmonic behaviour at the inverter power operation. It's reliability and speed make it a great tool for intelligent MLI control, real-time fault diagnosis and integration as a part of renewable energy systems.
Accurate experimental characterization of simple harmonic motion (SHM) is crucial for validating theoretical models and measurement methods. This study comparatively investigates three smartphone-based techniques, namely stroboscopic imaging, video tracking (Tracker software), and inertial sensor measurements (Phyphox app) applied to a vertical spring-mass system under identical conditions. Displacement time data were analyzed via nonlinear sinusoidal curve fitting and autocorrelation to determine oscillation periods, with theoretical predictions for both bare and mass-loaded configurations. A systematic uncertainty framework was implemented, accounting for temporal resolution, spatial calibration error, sensor noise, damping, and mass-loading corrections. Residual analysis indicated that deviations from ideal harmonic behavior were primarily due to instrumental resolution. The results show video tracking provides reliable quantitative measurements without perturbing system inertia, while inertial sensing yields consistent results when mechanical mass loading is modeled. Conversely, the stroboscopic method is limited by temporal discretization and manual analysis, restricting its use to qualitative visualization. These findings clarify the accuracy, limitations, and applicability of smartphone-based SHM measurements within a quantified experimental framework.
This study presented a novel synthesis of oxygenated graphitic carbon nitride thin films via DC magnetron sputtering, achieved without any intended oxygen supply from outside. Oxygen incorporation was occurred through residual gases i.e., atomic oxygen, hydroxyl radicals, water vapor, and CO2, trapped in the deposition chamber. The synthesis environment was carefully analyzed using a Quadrupole Residual Gas Analyzer (QRGA). This approach minimized defect formation typically associated with external oxygen supply. The resulting films were characterized using X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and UV-Vis spectroscopy to confirm successful oxygen integration.
Surface Acoustic Wave (SAW) resonator sensors have high sensitivity and selectivity in sensing Volatile Organic Compounds (VOCs) using mass-loading effects on the sensing layer. This paper describes the design and Finite Element Method (FEM)-based analysis of a delay-line SAW resonator for VOC sensing, focusing on PCE detection using polyisobutylene (PIB) as the active sensing layer. The analysis begins by describing the basic properties, applications, and limitations of SAW filters, together with a categorization scheme for acoustic devices. A detailed discussion about the optimization of SAW sensors is provided through the piezoelectric substrate, material properties, and fine-tuning of the IDT. Further optimization extended to multiple types of IDTs, including selection of materials, delay length to improve the performance of the SAW device. The frequency domain analysis has been performed to obtain S11 and displacement plot. The optimized SAW resonator used for VOC detection into the dynamic behavior of the filter. The proposed sensor was exposed to six organic gases, with their concentrations varying from 0 to 400 ppm. The frequency downshift of the SAW sensor was linear with the 400 ppm concentration of PCE gas, with a frequency shift (triangle f) of 270 kHz and a calculated sensitivity of 0.67 kHz/ppm. The structure under consideration has simulated high selectivity for PCE gas, the sensor is designed for 158 MHz range. These important findings of the study make work highly useful for optimization or application in diversified technological domains to benefit researchers and engineers in this field.
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.
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.
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 degrees 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.
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 (similar to 90 %). A DGS composed of rectangular slots is incorporated to minimize surface wave propagation and significantly enhance isolation between elements (|S-12| < -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 (similar to 5 dBi). Additionally, the orthogonal positioning of the resonating elements effectively reduces mutual coupling, reinforcing its suitability for high-performance, next generation wireless systems.
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 noncentrosymmetric 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.
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 & micro;m 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.
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, 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 strong southward interplanetary magnetic field component (Bz) was identified as the crucial factor determining the magnitude 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.
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.
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 similar to 1.7 x 10(17) 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 -TiO(2)heterojunction.
This paper presents a concept for a quantum simulator based on a superconducting qubit coupled to a readout resonator, designed to experimentally emulate the band structure of a one-dimensional crystal. The superconducting qubit, with its intrinsic periodic potential from the Josephson effect, serves as a direct analog of an electron in a periodic lattice. The Hamiltonian of the system is analyzed in two complementary regimes: the weak-coupling regime, corresponding to nearly-free electrons, and the strong-coupling regime, corresponding to electrons in the tight-binding limit. We show that the system can be continuously swept between these regimes using a flux-tunable symmetric DC-SQUID to vary the effective Josephson energy. To probe the resulting band structure, we propose an experimental method based on two-tone spectroscopy, which maps the qubit's flux-dependent transition spectrum via the dispersive shift of a coupled resonator. Numerical simulations confirm the feasibility of this approach, visualizing the transition from a broad band dispersion in the weak-coupling limit to exponentially narrow bands in the strong-coupling limit. This platform demonstrates how tunable superconducting circuits can be used as versatile quantum simulators for fundamental solid-state physics phenomena.
