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242 articles for “Multi-frequency”
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Improvement of Indirect Vector Control Induction Motor Drive Performance under Low Speed Operation using Five-Level Inverter
Abstract: The dynamic performance of vector controlled induction motor drive is poor and peak motor torque decreases under low speed operation. This reduction in torque is due to the non-linearity of voltage to frequency (Hz) during low frequency operation. The non-linearity is caused by stator voltage drop which in turn requires a larger percentage of overall terminal voltage. To overcome these problems multilevel inverter fed induction motor drive is presented in …
Published in Journal of Power Electronics and Power Systems · Vol. 3, Issue 2, 2013 · pp. 8–15 Read article
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Improve Power Quality in Photovoltaic and Wind Energy Systems Through the Utilization of DSTATCOM
Abstract: This paper explores the power quality challenges faced by distributed generation systems that are powered by renewable energy sources, e.g., wind and solar. It provides an in-depth examination of these power quality issues, starting with an overview and examination of basic standards. The research also explores power quality in power systems, specifically those connected to the electrical grid and renewable energy sources. It gives a comprehensive discussion of power quality …
Published in Journal of Power Electronics and Power Systems · Vol. 15, Issue 2, 2025 · pp. 33–44 Read article
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Measurement of Defects in Car Bearings and Its Effect on Ultrasonic Waves
Abstract: As one of the defects of roller bearings due to intermittent coupling forces and external impact loads,surface cracks due to corrosion or wear may have many defects for rotating machines. Surfacecracking on the bearing or its ball is one of the important factors in the efficiency of the bearing andits opening. It is useful to study these cracks and identify the type and size of these cracks for bearingsused in …
Published in Trends in Mechanical Engineering & Technology · Vol. 11, Issue 1, 2021 · pp. 44–49 Read article
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High Modulation Performance of a Designed InGaN Based 405 nm Multi-Quantum Well Violet Laser
Abstract: AbstractIn this work, the modulation performance characteristics of a designed 405 nm InGaN based multi-quantum well (MQW) Violet Laser are optimized and presented by varying injection current and differential gain. A maximum output power of 222.53 mW and a maximum resonance frequency of 18.79 GHz of the laser are obtained for 117 mA injection current, where, the differential gain is 4x10-16cm2. The differential quantum efficiency of the laser is obtained …
Published in Trends in Opto-electro & Optical Communication · Vol. 3, Issue 2, 2013 · pp. 7–13 Read article
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Subclinical Significant High Serum Immunoglobulin E Response to 20 Allergens: Age and Gender Based Study
Abstract: Background: Antigen-immunoglobulin E (IgE) reaction is an example of immediate allergic reactions. High serum IgE levels were reported in many diseases that linked to the multiple allergens. Objectives: This study aimed to measure the serum IgE against 20 allergens in patients who had a previous history of allergy due to unidentified precipitating factors. Methods: This retrospective study was conducted at the Al Zahraa Consultant Center for Allergy and Asthma that …
Published in Research and Reviews : A Journal of Immunology · Vol. 9, Issue 3, 2019 · pp. 1–6 Read article
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Case Study of Multipulse Converter System for IGBT Based Inverter in Induction Melting Furnace
Abstract: AbstractHarmonic mitigation is an important aspect for the smooth operation of modern power electronics converters, medical equipment, and home appliances which are generally fed by a common grid supply. In large power equipment such as induction furnaces, it becomes necessary to reduce or eliminate harmonics from the supply. In order to cater dynamic load cycle during complete melting cycles in induction furnaces, power needs to vary. This can be achieved …
Published in Journal of Semiconductor Devices and Circuits · Vol. 4, Issue 1, 2017 · pp. 17–23 Read article
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Extraction of speech Emotion Features Using MLP Classifier
Abstract: Speech Emotion Recognition is a thriving research topic. Speech emotion recognition use MLP classifier to categorize the emotions from the speech. This Speech is also used as the medium, through which one can express their feelings and mind state in human to machine interaction. The case is very easy where two humans communicate along with their emotions as by nature, they can recognize each other’s emotions. But for computer, if …
Published in Journal of Instrumentation Technology & Innovations · Vol. 12, Issue 3, 2022 · pp. 11–19 Read article
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Small Size High Gain Antenna and High Efficiency Rectifier for RF Energy Harvesting in 2.45 GHz ISM Band
Abstract: A streamlined microwave energy harvesting system to harvest energy in 2.45 GHz presented in this paper. An electromagnetically coupled square micro-strip antenna is designed and fabricated for formation in proposed system. Antenna gain of 6.7 db and bandwidth from 2.42to 2.47 GHz is achieved. The maximum gain of proposed antenna is 24 db at frequency 2.1 GHz. Rectifier circuit consists of a resonant circuit and a boosting circuit for enhancing …
Published in Journal of Microwave Engineering and Technologies · Vol. 3, Issue 1, 2016 · pp. 41–46 Read article
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A New Multiband Square Patch Antenna with Sierpinski Gasket Slot and Fractal Koch Loop at Ground
Abstract: This paper presents a multiband square patch antenna with Sierpinski gasket slot on top surface of substrate and fractal Koch loop at ground. This antenna has been designed to operate at 0 to 3 GHz frequency range and operates at five different resonant frequencies. The Koch loop at ground surface provides irregularities in current distribution; this affects the radiation property of the antenna.
Published in Journal of Electronic Design Technology · Vol. 4, Issue 1, 2013 · pp. 5–10 Read article
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Antenna as a Biosensor: A Survey
Abstract: AbstractBesides the communication, antenna has a great capability to sense the physical condition of surrounding environment and object. A minute change in the antenna design depending on the application or experimental conditions is required to use antenna as a sensor. Combining these antennas with passive RFID chips, results in a fabulous sensing device with large number of advantages like small size, light weight, low cost, low energy consumption, durable etc. …
Published in Recent Trends in Sensor Research & Technology · Vol. 5, Issue 1, 2018 · pp. 1–13 Read article
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Ultra-Wideband (UWB) Planar Monopole Antenna Array for Indoor Multimedia Devices
Abstract: AbstractA UWB planar monopole antenna array for indoor multimedia devices is presented. The base work of antenna includes a modified rectangular monopole to cover entire UWB (3.1 to 10.6GHz) and fed with a 50Ω microstrip line. The proposed antenna array is having a compact size of (80*30*1.6mm3) with a spacing of 0.5*lambda between two elements. To exhibit a wider bandwidth, a rectangular cut in the ground plane has been introduced …
Published in Journal of Microwave Engineering and Technologies · Vol. 5, Issue 2, 2018 · pp. 28–35 Read article
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Electromagnetic Transients in Strongly Non-Uniform Overhead High Voltage Lines
Abstract: This paper addresses the electromagnetic transients in high strongly non-uniform overhead voltage lines. For their simulation, a novel Laplace-domain approach has been introduced. The voltage and current patterns in terms of location and complex frequency are determined by a set of simultaneous algebraic and partial differential equations. To solve them numerically, an effective Mathematica code is proposed. By contrasting the outcomes of their application to multiple case studies with those …
Published in Journal of Power Electronics and Power Systems · Vol. 15, Issue 1, 2025 · pp. 30–36 Read article
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Design and Simulation of Discrete Time Multi-Input Multi-Output Optimal Controller to Control Active and Reactive Power of DFIG
Abstract: The control of active and reactive power of doubly-fed induction generator (DFIG) in a large scale wind farm has become an important issue for the improvement of wind energy system to provide efficient and reliable electrical power with safety. The control strategies of active power and reactive power can be classified in two types—direct power control and indirect power control. First control strategy has designed based on the chosen switching …
Published in Trends in Electrical Engineering · Vol. 5, Issue 1, 2015 · pp. 1–11 Read article
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Design and Evaluation of Nano-cantilever Beam for Sensing Application
Abstract: Sensor array offers several advantages such as selectivity enhancement towards analytes,multiple component analysis etc. In case of an array system, we see that one cantilever beamcan be set as a reference, while the other beams are subjected to varying loads. As a result,even a very small deflection would be detected with the help of adjacent beams, henceenhancing the sensitivity of the cantilever. By using an array of beams with differentfunctionalization …
Published in Recent Trends in Sensor Research & Technology · Vol. 7, Issue 3, 2020 · pp. 1–7 Read article
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The Role of Micro-Finance Institution to Improve Efficiency of Savings Mobilization in Gedeo Zone SNNPRS, Ethiopia
Abstract: Microfinance saving mobilization can help to gain financial independence, increase profitability and help microfinance institution to reach financial self-sufficiency. The study will seek to identify the factors affecting microfinance saving mobilization at microfinance institutions in Gedeo Zone, SNNPRs, Ethiopia. The study identified variables that can affect microfinance total saving. Nine variables were regressed with the dependent variable. The data for these variables was collected from microfinance institutions, National Bank of …
Published in Journal of Production Research & Management · Vol. 5, Issue 1, 2015 · pp. 27–38 Read article
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SDG 15: Life on Land-Challenges in Sustainable Utilization and Conservation of Water Resources
Abstract: Water is one of the most essential natural resources for sustaining life, ensuring agricultural productivity, and fostering socio-economic development. Its effective management and utilization are critical to reducing poverty, maintaining a stable climate, and promoting sustainable economic growth. However, increasing pressures from population growth, urbanization, and industrialization have significantly intensified the demand for water, creating numerous challenges. These include a decline in per capita water availability, falling groundwater levels in …
Published in Journal of Water Resource Engineering and Management · Vol. 12, Issue 1, 2025 · pp. 35–42 Read article
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Integrating RF Technologies for Robust Disaster Response and Recovery Systems
Abstract: In the aftermath of disasters, one of the greatest challenges is the failure of communication networks, which delays rescue operations and worsens human suffering. Radio Frequency (RF) technologies offer promising solutions as they enable wireless communication, sensing, and tracking without depending on fragile infrastructure. This paper presents a study of RF applications in disaster management and proposes a unique hybrid multi-layer framework that integrates environmental RF sensors, RFID-based tracking, drone-mounted …
Published in International Journal of Radio Frequency Innovations · Vol. 3, Issue 2, 2025 · pp. 24–27 Read article
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Low Power RF QPSK MODEM Design
Abstract: System-level simulation including design of CMOS circuits for radio frequency QPSK MODEM targeting applications in 2.45 GHz industrial, scientific and medical (ISM) band has been presented in this paper. Based on the QPSK architecture, the MODEM consists of an analog mixer using a voltage multiplier, a 90 °phase shifter, delay circuits, a voltage adder and a filter to detect the information. A code reuse subsystem block consisting of Chebyshev filter …
Published in Journal of VLSI Design Tools and Technology · Vol. 2, Issue 1-2-3, 2012 · pp. 75–86 Read article
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Millimeter Wave in Internet of Things Connectivity: A Study
Abstract: The internet of things (IoT) is rapidly evolving, connecting billions of devices and transforming industries. However, this growth is stretching the limitations of traditional wireless communication technologies. Enter millimeter wave (mmWave), a high-frequency band promising to revolutionize IoT connectivity by offering significantly higher bandwidth and lower latency. While still in its early stages of implementation, mmWave is poised to become a cornerstone of the next generation of IoT ecosystems. Millimeter …
Published in International Journal of Wireless Security and Networks · Vol. 3, Issue 1, 2025 · pp. 13–23 Read article
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A Comprehensive Study of various Multi-Area Hybrid Power Systems for Generation Control
Abstract: This paper is a detailed examination of multi-area hybrid power systems in the control of the generation taking into consideration the two area up to five area connected networks. As renewable energy sources are more and more integrated, and modern grids become more and more complex, the stability of the system itself and the frequency regulation have risen to a major issue. The study highlights the significance of Automatic Generation …
Published in International Journal of Electrical Power and Machine Systems · Vol. 3, Issue 2, 2025 · pp. 28–42 Read article