Farfield
Mostrando 1-12 de 23 artigos, teses e dissertações.
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1. Wideband Pattern Reconfigurable Printed-Yagi Antenna Array Based on Feed Structure
Abstract A pattern reconfigurable antenna array with two elements is designed in this paper. The antenna element is made up of a printed Yagi and feed structure with variable phase. By changing the states of diodes in the feed structure of these two elements, the far-field radiation phase of both elements can be changed. That is, the pattern reconfigurable f
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 19/06/2019
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2. Seismic Evaluation of Horizontally Curved Bridges Subjected to Near-Field Ground Motions
Abstract Horizontally curved bridges have more complex seismic behavior than straight bridges and have been more vulnerable to earthquakes. The present study aimed to evaluate the seismic response of concrete bridges with straight and arched box girder decks in isolated and non-isolated states. The results indicated that increasing the curvature of the non-i
Lat. Am. j. solids struct.. Publicado em: 14/03/2019
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3. Quantum Particle Swarm Optimization for Synthesis of Non-uniformly Spaced Linear Arrays with Broadband Frequency Invariant Pattern
Abstract This paper describes a method using Quantum Particle Swarm Optimization to obtain a broadband frequency invariant pattern for synthesis of nonuniformly spaced linear array of isotropic antennas. Two cases related to this work using QPSO have been studied, namely, in the first case, the generated frequency invariant far-field pattern is broadside in
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2017-09
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4. Far-field dynamic behavior of a half-space under an inertial strip foundation subjected to a time-harmonic force
Recent research works demonstrated that the interaction between the loads and the carrying structure's boundary which is related to the inertia of the load is an influential factor on the dynamic response of the structure. Although effects of the inertia in moving loads were considered in many works, very few papers can be found on the inertial effects of th
Lat. Am. j. solids struct.. Publicado em: 2013-05
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5. Evaluation of nacelle drag using Computational Fluid Dynamics
Abstract: Thrust and drag components must be defined and properly accounted in order to estimate aircraft performance, and this hard task is particularty essential for propulsion system where drag components are functions of engine operating conditions. The present work describes a numerical method used to calculate the drag in different nacelles, long and s
J. Aerosp. Technol. Manag.. Publicado em: 2010-08
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6. Experimental study of the propagation of a far-field disturbance in the turbulent flow through square array tube banks
This paper presents the experimental analysis of the propagation of a disturbance with a fixed frequency in the incidence velocity of the cross flow through a tube bank, and its influence on the velocity fluctuations inside the bank. The disturbance is generated outside the bank by vortex shedding from an obstacle. The tube banks investigated had square arra
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2009-09
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7. NUMERICAL MODELING OF SEWAGE PLUME DISPERSION FOR THE SANTOS OUTFALL / Modelagem numérica da dispersão da pluma do emissário submarino de Santos
Sewage plume dispersion for the Santos outfall was studied using numerical models, coupling hydrodynamic, near field and far field models. Experiments were conducted for the 1979 original outfall design, for the new 2009 outfall configuration and also for a third arrangement suggested here, which duplicates the emissary length comparatively to the original 1
Publicado em: 2009
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8. Desenvolvimento de emissores de radiação na faixa de Terahertz baseados em compostos III-V fotocondutivos para espectroscopia e formação de imagens / Development of Terahertz radiation emitters based on photoconductive III-V compounds for spectroscopy and imaging
A radiação eletromagnética em Terahertz (THz) situa-se na faixa de 1012 Hz, com comprimentos de onda associados variando de 30 µm até 3 mm. É possível então usar esta radiação para investigar propriedades físicas de materiais que requerem uma definição desta ordem. Além de aplicações na espectroscopia, estes comprimentos de onda são capazes
Publicado em: 2009
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9. Transient gas phase interaction effects during droplet-stream combustion
Gas-phase transient effects during the combustion of an infinite linear array of droplets are studied in the limit of infinite Damköler number and in the absence of surrounding convective effects. The present study stems from the quantification of truncation-distance effects on the droplet mass vaporization rate, flame position and flame shape in quasi-stea
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2007-09
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10. Supersonic acoustic intensity : implementation and evaluation / Intensidade acustica supersonica : implementação e verificação
This work presents an experimental implementation and evaluation of the acoustic parameter named Supersonic Acoustic Intensity (SAI) which permits determining the part of the acoustic intensity of sound source that will be radiate to farfield. This parameter permits quantify precisely the radiation efficiency or acoustic radiator to solve the vibroacoustic p
Publicado em: 2006
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11. Desenvolvimento de um microscópio óptico e magnetoóptico de varredura em campo-próximo / Development of a Magneto-optical Scanning Near-field Optical Microscope (MO-SNOM)
To support nanosciences evolution, there is a strong demand for developing new instrumentation devoted to nano-scale characterization. In this context, the development of the Scanning Near-field Optical Microscope (SNOM) took place. In contrast to traditional optical microscopes, SNOM deals with evanescent electromagnetic radiation and, consequently, the res
Publicado em: 2005
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12. DEVELOPMENT AND CHARACTERIZATION OF A FIELD MAGNETIC TRANSDUCER BASED ON GIANT MAGNETOIMPEDANCE EFFECT / DESENVOLVIMENTO E CARACTERIZAÇÃO DE UM TRANSDUTOR MAGNÉTICO BASEADO NO EFEITO DA MAGNETOIMPEDÂNCIA GIGANTE
In this dissertation, it is proposed the design of a magnetic field to voltage transducer based on the Giant Magnetoimpedance phenomenon (GMI), characterized by an innovative geometric configuration. In order to attain the best near-field sensibility and far-field immunity, the transducer`s sensitive element and electronic circuit were planned and implemente
Publicado em: 2005