Power Efficiency
Mostrando 1-12 de 476 artigos, teses e dissertações.
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1. Radially Periodic Metasurface Lenses for Magnetic Field Collimation in Resonant Wireless Power Transfer Applications
Abstract In this paper, a new procedure and topology of magnetic metasurface lens are proposed for improving the performance of Resonant Wireless Power Transfer systems. Firstly, three subwave-length unit cells are optimized in order to get negative magnetic permeability in the same frequency, each one with a different refractive index, and they are experime
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
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2. ENERGY EFFICIENCY OF AGRICULTURAL TRACTORS EQUIPPED WITH CONTINUOUSLY VARIABLE AND FULL POWERSHIFT TRANSMISSION SYSTEMS
ABSTRACT The efficiency of agricultural tractor transmission has been improved over the years, with new concepts such as Continuously Variable Transmission (CVT) and Full Powershift (FPS) evolving in advanced technologies. Both options seek to offer the farmer greater operational results with lower energy expenditure, necessitating studies to assess the effe
Engenharia Agrícola. Publicado em: 2022
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3. A 2.4 GHz Coplanar Solar Cell Patch Antenna with a Semi-Analytical Evaluation of Temperature Effects
Abstract Solar cells integrated with antennas have aroused scientific interest as an attractive energy source alternative in low power devices for IoT and Wireless Sensor Network applications. Since the space for all components in the systems is scarce, different integration ideas have been proposed in this field. However, further analysis of the performance
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
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4. Enhanced Catalytic Performance of Strontium-Doped Lanthanum Manganites by the Presence of Molybdenum Oxides for Electro-Reduction of Hydrogen Peroxide
In this work, two catalysts, lanthanum manganite strontium-doped perovskite without (LSM) and with (LSMMO) mixed molybdenum oxides, were synthesized by the sol-gel route and deposited by immersion in carbon cloth substrates. Their performance as cathodes in the hydrogen peroxide reduction reaction (HPRR) and oxygen reduction reaction (ORR) was investigated t
Journal of the Brazilian Chemical Society. Publicado em: 2022
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5. Root morphology and kinetics of Zn absorption by roots of common bean influenced by Zn status of the root environment
ABSTRACT Understanding the kinetics of Zn absorption by roots and its effect on morphology of this organ is relevant for improving crop management, but still poorly studied for common beans. Therefore, an experiment was conducted in a hydroponic system with five initial concentrations of Zn (CZnI): 0.0; 1.0; 4.0; 16.0 and 48.0 µmol L-1. The experiment was i
Rev. Ceres. Publicado em: 2021-08
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6. Compact, Broadband, and Omnidirectional Antenna Array for Millimeter-Wave Communication Systems
Abstract In this paper, a millimeter-wave printed quadrupole antenna is proposed. It consists of two symmetric printed dipoles that make the quadrupole radiating power omnidirectionally. Such an arrangement eliminates the influence of the ground as reflector. Simulation results show that the quadrupole antenna exhibits a broad impedance bandwidth and an enha
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2021-06
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7. Comparison Between Three- and Four-coil Wireless Power Transfer Systems with Resonant Coils
Abstract In this paper, it is demonstrated that the efficiency and ability to transfer power to the load in three-coil wireless power transfer (WPT) systems are always higher than in equivalent four-coil ones. On the other hand, it is shown that there are features attainable in four-coil WPT system that are not in three-coil ones. For instance, in a four-coi
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2021-03
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8. TECHNICAL AND ECONOMIC FEASIBILITY OF USING A VARIABLE-FREQUENCY DRIVE IN MICRO-IRRIGATION SYSTEMS
ABSTRACT Irrigation is essential for the development of crops in regions with scarcity or irregular rainfall distribution, enabling high productivity. However, the use of water resources and electrical energy leads to a concern with irrigation efficiency. Pressure demand varies during the operations of irrigation systems and the appropriate pressure can be r
Eng. Agríc.. Publicado em: 2021-02
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9. Impact of Continuing Education on the Quality of Blood Pressure Measurement
The properties of lanthanides allow them to be used as contrast agents for magnetic resonance imaging, thereby helping to differentiate between tissues, organs, and pathologies more efficiently. Lanthanides contain thermosensitive energy levels that aid identification of cancer and healthy cells. This work investigates the GdVO4 matrix obtained by the non-hy
Int. J. Cardiovasc. Sci.. Publicado em: 2021-02
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10. Er3+/Yb3+-Doped GdVO4 Obtained by the Non-Hydrolytic Sol-Gel Route and Potential Application as Up-Conversion Thermometer
The properties of lanthanides allow them to be used as contrast agents for magnetic resonance imaging, thereby helping to differentiate between tissues, organs, and pathologies more efficiently. Lanthanides contain thermosensitive energy levels that aid identification of cancer and healthy cells. This work investigates the GdVO4 matrix obtained by the non-hy
J. Braz. Chem. Soc.. Publicado em: 2021-02
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11. High Efficiency Continuous Inverse Class-F Power Amplifier with Modified Current Waveform
Abstract Continuous inverse class-F (CICF) is a recent mode of harmonically-tuned RF power amplifiers used to extend the operating bandwidth of the conventional narrowband class-F−1 power amplifier by producing variable set of drain current waveforms and load admittances that give the same operating efficiency. In this work, a new approach of analysis is d
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2020-09
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12. EVALUATION OF THE RELATIVE PROTECTION FACTOR OF ROSEMARY EXTRACT IN BIODIESEL IN THE PRESENCE OF TRANSITION METAL IONS
Biodiesel contains unsaturated methyl esters making it susceptible to oxidation reaction. Among the factors that cause oxidative instability is the contamination by transition metal ions that in small quantities catalyze the oxidation reaction. The objective of this work was to evaluate the relative protection factor of rosemary extract, in biodiesel, in the
Quím. Nova. Publicado em: 2020-09