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397 articles for “Frequency”
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Selection of Appropriate Porous Material for Designing and Developing Hybrid Absorptive Muffler: A Wave 1-D Based Approach
Abstract: In this study, glass wool and rock wool are used as sound-absorbing materials to assess the sound transmission loss (STL) of hybrid absorptive mufflers. Improving the muffler's acoustic performance and assessing how well these materials attenuate noise are the main goals. Rock wool, which offers greater thermal resistance and broader frequency absorption, is contrasted with glass wool, which is renowned for its lightweight construction and high-frequency absorption. Wave 1-D simulation …
Published in Journal of Polymer & Composites · Vol. 13, Issue 3, 2025 · pp. 148–160 Read article
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Intelligent Design Approaches in Microwave Engineering Using Machine Learning Techniques
Abstract: In microwave engineering, machine learning (ML) has become a potent technology allowing quicker design cycles, improved modelling accuracy, and automatic optimisation of complicated systems. Recent developments in the use of ML methods to microwave components and systems, including antennas, filters, and high-frequency circuits, are summarised in this study. In the framework of electromagnetic simulation, surrogate modelling, and parameter extraction, supervised and unsupervised learning algorithms are addressed. Moreover, the study looked …
Published in Journal of Microwave Engineering and Technologies · Vol. 12, Issue 2, 2025 · pp. 31–38 Read article
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Feature Extraction and Analysis of Bearing Faults: A Review
Abstract: One of the most important steps in identifying bearing problems is feature extraction. In order to provide a more meaningful dataset, it entails locating and extracting pertinent features from raw bearing vibration signals. Tasks involving categorization and prediction can then make use of these attributes. In many practical applications, such as monitoring rotating machinery or electronic components, the raw signals collected (e.g., vibration, current, temperature) are often complex, high-dimensional, and …
Published in Trends in Mechanical Engineering & Technology · Vol. 15, Issue 2, 2025 · pp. 20–28 Read article
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A Study on Drone Hacking: Vulnerabilities and Mitigation Techniques
Abstract: This paper explores the current cybersecurity landscape surrounding Unmanned Aerial Systems (UAS), commonly known as drones. With rapid growth in commercial and recreational drone use, the risk of cyber-attacks has also increased. This study highlights real-world vulnerabilities such as GPS spoofing, Wi-Fi hijacking, and firmware exploitation. It also suggests practical mitigation techniques, including encryption, real-time anomaly detection using machine learning, and secure communication protocols. The goal is to support researchers, …
Published in International Journal on Drones · Vol. 1, Issue 2, 2025 · pp. 1–8 Read article
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Pattern Reconfigurable Yagi-Uda Antenna
Abstract: This study proposes a prototype of a reconfigurable Yagi-Uda Antenna that is capable of reconfiguration of the radiation pattern. The proposed flexible antenna will work as the director, and reflector can be switched in a Yagi-Uda set up antenna by using a radio frequency PIN diode. The radiating signals can be directed at desired signals away from undesirable signals that are impinging on the antenna in opposite directions. The antenna …
Published in Journal of Microwave Engineering and Technologies · Vol. 12, Issue 3, 2025 · pp. 14–20 Read article
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Establishment of A Set of Similarity Prerequisite Conditions for Low-Cost Similitude Design of Structural System
Abstract: Similitude theory and method is a branch of engineering to establish necessary and sufficient conditions for similarity among complex phenomena. It is of great significance to develop the theory and application method in a more comprehensive way so that the similitude theory can be widely applied to low-cost designs of modern complex structural systems When designing a similitude structural system with various loads and boundary conditions, including rotating machines, it …
Published in Journal of Production Research & Management · Vol. 15, Issue 3, 2025 · pp. 1–15 Read article
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5G and up to 6G
Abstract: The 5th generation of mobile networks is called 5G, and the next generation, 6G is expected to arrive soon. With the promise of faster speeds, less latency, and increased connectivity, 5G technology has revolutionized mobile communications. However, the 6G vision is already taking shape as the need for high-performance networks keeps increasing. By offering ultra-high-speed communication, smooth artificial intelligence (AI) integration, extensive Internet of Things (IoT) connectivity, and support for …
Published in International Journal of Wireless Security and Networks · Vol. 3, Issue 2, 2025 · pp. 01–06 Read article
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Study on the Method of Constructing a System of Linear Equations for Calculating Aerodynamic Derivatives
Abstract: The aerodynamic derivatives can be calculated from the unsteady hydrodynamic forces experienced by the harmonic-oscillating vehicle. Until now, unsteady flow field analysis in aerodynamic derivative calculations has been applied mainly to thin bodies based on potential theory MSC. Nastran is a typical application based on potential theory MSC. Natran can calculate the aerodynamic derivatives of the vehicle relatively well in the subsonic region, but in the supersonic region, the fuselage …
Published in Journal of Experimental & Applied Mechanics · Vol. 16, Issue 3, 2025 · pp. 14–24 Read article
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Prediction of Depth-Induced Stress Distribution and Maintenance Cost Implications for Submerged Structural Components
Abstract: This study investigates the influence of water depth on stress distribution and structural integrity of submerged mechanical components . Structural models fabricated from mild steel, stainless steel, carbon steel, and copper alloy were examined under hydrostatic loading corresponding to water depths between 30 cm and 150 cm. Results indicate that normal and shear stresses increased proportionally with depth due to intensified hydrostatic pressure. Mild steel exhibited the highest stress concentrations, …
Published in International Journal of Fracture Mechanics and Damage Science · Vol. 3, Issue 2, 2025 · pp. 29–35 Read article
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Determinants of the Adoption of chemical Fertilizer in Kaffa, Bench Sheko and Sheka zones of Southwest Ethiopia
Abstract: Agriculture is the backbone of the Ethiopian economy, but the production system was backward, and the adoption of agricultural technology was low. This study aims to identify and determine factors affecting smallholder farmers' adoption of chemical fertilizer. Bita, Chena, Andiracha, and Sheyi Bench district of the southwest Ethiopia region was selected for this study. Household individual survey interview, key informant interview, and focus group discussion were the primary data collection …
Published in Research & Reviews : Journal of Agricultural Science and Technology · Vol. 15, Issue 1, 2026 · pp. 1–12 Read article
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Thermal Stability and Sound Absorption Behaviour of Sisal–Luffa Hybrid Epoxy Composites for Automotive Interior Applications
Abstract: Natural fiber–reinforced composites are gaining popularity as substitutes for synthetic fiber composites because of their environmental and sustainability advantages. Their adoption is steadily increasing across various industries. In automotive interior applications, these materials must exhibit strong thermal stability and efficient sound absorption to meet performance requirements. In this experiment, composites were made by mixing sisal and luffa fibers with epoxy resin. The hand lay-up method was used for fabrication. Two …
Published in Journal of Polymer & Composites · Vol. 14, Issue 2, 2026 · pp. 144–157 Read article
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Dual-Wavelength and Tunable Fiber Lasers for Microwave Photonic Applications
Abstract: Dual-wavelength and tunable fiber lasers have emerged as key enabling technologies for advanced microwave photonic (MWP) systems, offering high spectral purity, wide tunability, and enhanced stability. These laser sources play a critical role in generating and processing microwave and millimeter-wave signals through optical means, enabling low-loss transmission and immunity to electromagnetic interference. This review presents recent progress in the design and implementation of dual-wavelength and tunable fiber lasers, highlighting their …
Published in Journal of Microwave Engineering and Technologies · Vol. 13, Issue 1, 2026 · pp. 17–25 Read article
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Electromagnetic Field Effects on Biological Systems and Safety Evaluation of Microwave Exposure
Abstract: The increasing use of wireless communication systems, radar technologies, and microwave- based devices has raised growing concerns regarding the potential biological effects of electromagnetic fields (EMFs) on living systems. This review paper investigates the interaction between electromagnetic field exposure, particularly in the microwave frequency range, and biological tissues, with a focus on safety implications and risk assessment. Microwave radiation, commonly emitted from mobile phones, Wi-Fi routers, and industrial equipment, can …
Published in Journal of Microwave Engineering and Technologies · Vol. 13, Issue 1, 2026 · pp. 26–33 Read article
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Quantitative Image-Based Assessment of Degradation Patterns in Polymer-Based Medical Implants
Abstract: Polymer-based medical devices are widely used in clinical practice, where long-term material degradation can compromise performance and patient safety. Traditional polymer degradation studies predominantly rely on laboratory-based experiments, which often fail to capture real-world operational and usage conditions. In this study, a multimodal, data-driven framework is proposed for the quantitative assessment of degradation patterns in polymer-based medical devices using publicly available clinical failure data. Structured operational parameters, including cumulative usage …
Published in Journal of Polymer & Composites · Vol. 14, Issue 2, 2026 · pp. 1510–1518 Read article
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Comparative Study of Uniform and Non-Uniform Beams Resting on Bi-Parametric Foundation Under Harmonic Load with Time Dependent Boundary Conditions
Abstract: In this study, we investigated uniform and non-uniform damped and time-dependent elastic beams resting on bi-parametric foundation subjected to harmonically varying moving load. The beam properties, including moment of inertia and mass per unit length, were assumed to be either constant or varying with position along the beam span in this study. The solution methods were based on Mindlin-Goodman method, Fourier sine transformation, weighted residual method, integral transformation, and theory …
Published in International Journal of Mechanical Dynamics and Systems Analysis · Vol. 4, Issue 1, 2026 · pp. 33–50 Read article
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Development of Compact RF Filters for Modern Wireless Communication Systems
Abstract: Modern wireless communication systems such as 5G, 6G, Internet of Things (IoT), satellite communication, radar systems, and smart wireless networks require compact and highly efficient RF filters for reliable signal transmission and interference suppression. RF filters are important components that allow desired frequency signals to pass while rejecting unwanted frequencies and noise. With the rapid growth of wireless devices and limited spectrum resources, the demand for miniaturized, low-loss, multi-band, and …
Published in Journal of Microwave Engineering and Technologies · Vol. 13, Issue 2, 2026 Read article
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Integrated Explainable Forecasting and Metaheuristic PI Optimization for LFC/AGC
Abstract: Since the last decade world has seen a paradigm shift towards alternate sources of energy, due to significant increase in population and ever-rising demand. However, the traditional systems were not designed to cope with these alternate sources and on the other hand these systems are posed with the challenges of efficiency and intermittency. So, it is inevitable that we need to design a system wherein forecasting data has to be …
Published in Trends in Electrical Engineering · Vol. 16, Issue 2, 2025 Read article
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Dielectric Studies of 0.5Ba0.8Ca0.2TiO3.0.5CaCu3Ti4O12 Nanoceramic Fabricated by Chemo-mechanical Process
Abstract: The present investigation is aimed toward investigate a straightforward, inexpensive, and environmentally friendly chemo-mechanical method for preparing high-dielectric materials, specifically 0.5Ba0.8Ca0.2TiO3.0.5CaCu3Ti4O12 (BCT-CCTO), by combining metal nitrate combustion with solid TiO2 powder and titanium isopropoxide, Ti (OR)4. The composite was prepared by the mixing of individual materials of Ba0.8Ca0.2TiO3 and CaCu3Ti4O12 through the chemo-mechanical method. Initially, 99% pure Ba (NO3)3, Cu (NO3)2∙3H2O, TiO2 and glycine were taken in their stoichiometry ratios. …
Published in Journal of Polymer & Composites · Vol. 13, Issue 2, 2025 · pp. 12–21 Read article
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Unraveling Mixed Ionic-Electronic Conduction in Lithium-Substituted Rubidium Tetra Titanates via Dielectric Spectroscopy and EPR Analysis
Abstract: Lithium-substituted Rubidium Tetra Titanates with varying concentrations of lithium carbonate (Li₂CO₃) — specifically 0.01, 0.05, and 0.1 molar percentages — were successfully synthesized using a conventional high-temperature solid-state reaction method. The resulting compounds follow the general chemical formula Rb₂₋ₓLiₓTi₄O₉. X-ray diffraction (XRD) analysis confirmed that lithium ions were successfully incorporated into the crystal lattice without disrupting the fundamental layered structure of the host material. The crystal system remained monoclinic across …
Published in Research & Reviews : Journal of Physics · Vol. 14, Issue 2, 2025 · pp. 19–29 Read article
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Machine Learning-Based Channel Estimation in 5G, Beyond-5G, and 6G Networks: Recent Advances and Future Directions
Abstract: Accurate channel estimation is one of the most fundamental challenges in modern wireless communication systems. In fifth- generation (5G) New Radio (NR) and emerging sixth-generation (6G) networks, precise knowledge of the wireless channel is essential for achieving reliable data transmission, high spectral efficiency, and low Bit Error Rate (BER). Conventional estimation techniques such as Least Squares (LS) and Minimum Mean Square Error (MMSE) rely on mathematical channel models and predefined …
Published in Journal of Telecommunication, Switching Systems and Networks · Vol. 13, Issue 2, 2026 Read article