Acoustic Resonance
Mostrando 1-12 de 34 artigos, teses e dissertações.
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1. Optical Fiber Spool Acoustic Wave Resonances Employing a Mach-Zehnder Interferometer in Vacuum Chamber
Abstract The longitudinal, flexural, and torsional modes of acoustical resonances are presented for a long and small thickness cylindrical fiber spool. The fiber spool is built using a monomode optical fiber tightly wound in a helix form around a cylindrical Styropor. The acoustical resonance values are obtained using a Mach Zehnder interferometer with the f
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2020-12
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2. Ultrafast Dynamics of Au Nanopyramid Interfaces Prepared by Nanosphere Lithography: Effect of Substrate Chemical Composition
This work describes ultrafast spectroscopy studies of Au triangular pyramid particle arrays deposited over glass (termed Au/glass), and 190 nm indium tin oxide (ITO) film (termed Au/ITO/glass) prepared by nanosphere lithography. The linear absorption spectra of Au/glass and Au/ITO/glass exhibit surface plasmon resonances at 800 and 870 nm, respectively, in g
J. Braz. Chem. Soc.. Publicado em: 2016-02
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3. Acoustic Characterization of Sugarcane Bagasse Particleboard Panels (Saccharum officinarum L)
The use of sugarcane bagasse minimizes the environmental impact and contributes to the creation of a new product with low density, good sound absorption capacity and can improve the acoustic conditions of buildings. The goal of this study aims to determine the intensity response of sugarcane bagasse particleboard panels’ sound absorption and compare them w
Mat. Res.. Publicado em: 2015-08
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4. Atypical Manifestation of Vestibular Schwannoma
Introduction Vestibular schwannoma (also known as acoustic neuroma) is a benign tumor whose cells are derived from Schwann sheaths, which commonly occurs from the vestibular portion of the eighth cranial nerve. Furthermore, vestibular schwannomas account for ∼8% of intracranial tumors in adults and 80 to 90% of tumors of the cerebellopontine angle. Its
Int. Arch. Otorhinolaryngol.. Publicado em: 2013
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5. ANALISE E PROJETO DO CONVERSOR BUCK INTERCALADO PARA ALIMENTAÇÃO DE LÂMPADAS DE DESCARGA EM ALTA PRESSÃO DE ALTA POTÊNCIA / INTERLEAVED BUCK CONVERTER ANALYSIS FOR HIGH POWER HIGH INTENSITY DISCHARGE LAMPS SUPPLYING
This work presents a detailed analysis about the interleaved buck converter applied to electronic ballasts to supply high power HID lamps, assuming the input voltage as a PFC stage output. As the output capacitor has a maximum value to be applied in parallel with the lamp, parallel operated converters are a suitable choice because the output current ripple c
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 29/02/2012
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6. SISTEMAS ELETRÔNICOS DE ILUMINAÇÃO BASEADOS NOS CONVERSORES CA/CA / LIGHTING SYSTEMS ELECTRONIC BALLASTS BASED ON AC CHOPPERS
Este trabalho visa aprimorar os sistemas de iluminação pública aplicando reatores eletrônicos baseados em conversores CA/CA. Apresenta-se um comparativo entre conversores tradicionais CC/CC, aplicando a eles interruptores bidirecionais em tensão e corrente, de modo a alimentar a lâmpada de alta pressão de sódio na frequência da rede de alimentação
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 23/08/2011
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7. MONITORING MECHANICAL STRESS ON FLEXIBLE RISERS BY ELECTROMAGNETISM / MONITORAMENTO DE TENSÃO MECÂNICA EM RISERS FLEXÍVEIS POR ELETROMAGNETISMO
As técnicas eletromagnéticas de inspeção têm se destacado como as únicas com potencial de determinar, de forma não invasiva, a tensão mecânica nos arames de sustentação dos risers flexíveis. Como o duto flexível é uma estrutura complexa, constituída por várias camadas de aço e de termopl ástico, as técnicas tradicionais de inspeção não
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 10/08/2011
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8. Efectos acústicos inmediatos de una secuencia de ejercicios vocales con tubos de resonancia
PURPOSE: the purpose of this study is to determine the immediately acoustic effect of phonatory exercise sequence using resonance tubes in a group of dysphonic subjects METHOD: a unique sequence of four phonatory tasks within resonance tubes was applied in twenty-four teachers with dysphonic voices, assessed perceptually with GRBAS scale. Voice samples were
Revista CEFAC. Publicado em: 16/11/2011
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9. Liquid rocket combustion chamber acoustic characterization
Abstract: Over the last 40 years, many solid and liquid rocket motors have experienced combustion instabilities. Among other causes, there is the interaction of acoustic modes with the combustion and/or fluid dynamic processes inside the combustion chamber. Studies have been showing that, even if less than 1% of the available energy is diverted to an acousti
J. Aerosp. Technol. Manag.. Publicado em: 2010-12
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10. COATING CONTRIBUTION ON THE ACOUSTIC PERFORMANCE OF MASONRY WALLS / AVALIAÇÃO DA CONTRIBUIÇÃO DO REVESTIMENTO NA ISOLAÇÃO SONORA DE PAREDES DE ALVENARIA
The research presents the sound insulation in masonry walls coated with plaster. Three walls were built in laboratory, studied in specific tests. Measurements were carried out varying some components of the wall, such as the type of the block and the combinations of coarse mortar, plaster and stucco on the faces of the wall. The mortars used in the tests wer
Publicado em: 2010
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11. Efeito da expansão rápida da maxila sobre a nasofaringe e o volume nasal: avaliação por ressonância magnética e rinometria acústica / Effect of rapid maxillary expansion on the nasopharynx and nasal volume: assessment by magnetic resonance imaging and acoustic rhinometry
A mordida cruzada posterior é uma das maloclusões freqüentemente encontrada em pacientes respiradores bucais e a expansão rápida da maxila é o procedimento ortodôntico/ortopédico mais utilizado para a sua correção. Os objetivos deste estudo foram avaliar a área da nasofaringe, por meio da ressonância magnética (RM), e o volume da cavidade nasal,
Publicado em: 2010
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12. Estudo de materiais magnéticos através de técnicas fototérmicas : efeito magnetocalórico e filmes finos / Study of magnetic materials using photothermal techniques : magnetocaloric effect and thin films
The magnetocaloric effect (MCE) has been widely studied because of its possible application in magnetic refrigeration. The search for suitable materials has intensified over the last decade, with a demand not only for the preparation of new materials but also for their complete characterization. The aim of this work is to apply the photothermal techniques to
Publicado em: 2010