Acoustic Waves
Mostrando 1-12 de 60 artigos, teses e dissertações.
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1. Caracterización de daño por “b-value” de eventos de emisión acústica en ensayos de rotura de roca andesita
ABSTRACT Acoustic emission is a phenomenon that produces elastic waves when materials are subjected to tension. These waves spread towards the material surface where they are received by sensors that convert them into electrical signals for further analysis. In this work, acoustic emission signals were analysed in order to evaluate the amount of accumulated
Matéria (Rio J.). Publicado em: 19/07/2018
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2. Análisis de la forma de onda de señales de Emisión Acústica producida en ensayos de interfaces ceramo-metálicas
ABSTRACT The study of ceramic-metal interface is of special importance in odontology area by the current demand about dental prostheses, so it is very important to be more and more similar to natural teeth and with a long service life. With the aim of assessing in detail the behavior of ceramic-metal interface used in dental restorations systems, in this wor
Matéria (Rio J.). Publicado em: 19/07/2018
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3. Methods of Hearing Preservation during Cochlear Implantation
Abstract Introduction Recent advances in surgical techniques and electrode design have made residual hearing preservation during cochlear implantation (CI) possible, achievable, and desirable. Objectives The objective of this study was to review the literature regarding methods used for hearing preservation during CI surgery. Data Synthesis We performe
Int. Arch. Otorhinolaryngol.. Publicado em: 2017-09
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4. Ultrasonic method of microvibration detection: part II - additional processing method and applications
Abstract Introduction In the last 28 years, the scientific community has been using elastography to evaluate the mechanical properties of biological tissue. The aim of this work was the optimization of the UDmV method, presented in Part I of the series, by means of modifying the technique employed to generate the reference sine and cosine functions, used fo
Res. Biomed. Eng.. Publicado em: 17/08/2017
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5. Acoustic Birefringence and Poisson's Ratio Determined by Ultrasound: Tools to Follow-Up Deformation by Cold Rolling and Recrystallization
Poisson's ratio and birefringence, both measured by ultrasound, are used to follow the evolution of the anisotropy in ASTM A-36 steel plates cold-rolled between 5 and 50% deformation, and then subjected to recrystallization at 900 and 1000 ºC. Times of flight of longitudinal and shear waves along the thickness of the plates were measured. As orthotropy incr
Mat. Res.. Publicado em: 31/07/2017
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6. Finite element simulation of laser generated ultrasound waves in aluminum plates
The Laser-Ultrasonic technique uses laser energy to generate ultrasound waves in various solids. This technique allows inspecting large structures. The generated ultrasound wave form is affected by features of laser pulse (wavelength, pulse duration, power density). The goal of this paper is to study the effects of laser parameters (rise time and beam radius
Lat. Am. j. solids struct.. Publicado em: 2014
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7. A study on acoustic behavior of poroelastic media bonded between laminated composite panels
A study on the acoustic behavior of double-walled panels, with sandwiched layer of porous materials is presented within Classical Laminated Plate Theory (CLPT) for laminated composite panels. For this purpose, equations of wave propagation are firstly extracted based on Biot's theory for porous materials, then the transmission loss (TL) of the structure is e
Lat. Am. j. solids struct.. Publicado em: 2014
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8. Cortical activity in tinnitus patients and its modification by phonostimulation
OBJECTIVE: The goal of this study was to observe spontaneous cortical activity and cortical activity modulated by tinnitus-matched sound in tinnitus patients and healthy subjects with no otoneurologic symptoms. METHOD: Data were prospectively collected from 50 tinnitus patients and 25 healthy subjects. Cortical activity was recorded in all subjects with e
Clinics. Publicado em: 2013-04
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9. Construcción de una cámara anecoica para la caracterización de la pérdida de transmisión sonora
In this paper a study of the sound transmission loss (PT) in various everyday materials such as styrofoam, cardboard, glass, cotton and sisal is performed. The experimental setup consists of two sound level meters and an absorbing anechoic chamber. It is shown in detail how to build with inexpensive materials the anechoic chamber used to measure the PT. From
Rev. Bras. Ensino Fís.. Publicado em: 2012-12
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10. Fast Multipole Burton-Miller Boundary Element Method for Two and Three-Dimensional Acoustic Scattering
Abstract: A multistage adaptive fast multipole method is used to accelerate the matrix-vector products arising from the Burton-Miller boundary integral equations, which are formed in a boundary element method. The present study considers the scattering of acoustic waves, generated by localized sources from bodies with rigid surfaces. Details on the implement
J. Aerosp. Technol. Manag.. Publicado em: 2012-06
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11. Approximate expressions for the reflection coefficient of ducts terminated by circular flanges
Estimating the magnitude of the pressure reflection coefficient |R| and the end correction l at the open end of ducts is a critical procedure when designing or predicting the acoustic behavior of acoustical systems, such as exhausts, tailpipes, mufflers, loudspeaker enclosures and so on. For cylindrical ducts and plane waves, exact intricate solutions exist
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2012-06
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12. Modelagem de ondas ultrassônicas refletidas por superfícies de geometrias diversas. / Modeling for ultrasonics waves of reflected surfaces of various geometries.
Neste trabalho são analisados os campos acústicos gerados por transdutores ultrassônicos planos e circulares, do tipo pistão plano, no modo pulso-eco, trabalhando como emissor e receptor de ondas, com freqüências de 1,6 MHz, 2,25 MHz e 5 MHz. As ondas emitidas por esses transdutores interagem com interfaces denominadas alvos, com diversas geometrias de
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 20/05/2011