Acoustic Surface Waves
Mostrando 1-11 de 11 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. 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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4. Structural damage identification via accoustic wave propagation approach using computational intelligence techniques / Identificação de dano estrutural via abordagem de propagação de ondas acústicas utilizando técnicas de inteligência computacional
No presente trabalho, um algoritmo algébrico sequencial é utilizado para descrever a propagação de ondas acústicas ao longo de uma barra e utilizado na identificação de danos. Esse algoritmo é validado com base nos conficientes de sensibilidade dos ecos correspondentes aos diferentes cenários de danos apresentados. Na formulação do problema de ide
Publicado em: 2010
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5. Tin and zinc oxides semiconductor devices / Dispositivos semicondutores a partir de óxidos de estanho e zinco
This work presents the study and development of semiconductor devices base on tin and zinc oxides. The first device is related to the development of pH sensors based on field effect, while the second device uses surface acoustic waves for the transport of carriers related to a single photon detector device. Initially, the semiconductors were used as hydrogen
Publicado em: 2009
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6. Processos dinÃmicos e evolutivos da zona costeira de Itamaracà por sensoriamento remoto e medidas in situ
The coastal zone of Itamaracà is like a highly dynamic environment where land and oceanic processes interact altering frequently coastal characteristics. In this context, this current study examines the responsible processes of such changes from the development and application of methodologies, which includes digital image processing and the obtaining of in
Publicado em: 2009
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7. Modelagem analítica da propagação de ondas de tensão em tubos de parede fina visando a localização de uma fonte pontual harmônica em sua superfície / Analytic model of the stress waves propagation in thin wall tubes, seeking the location of a harmonic point source in its surface
Vazamentos em tubos pressurizados geram ondas acústicas que se propagam através das paredes destes tubos, as quais podem ser captadas por acelerômetros ou por sensores de emissão acústica. O conhecimento de como estas paredes podem vibrar, ou de outro modo como as ondas acústicas se propagam neste meio, é fundamental em um processo de detecção e loc
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 09/06/2006
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8. Estudo das propriedades acusticas do filme finode TiO2 usando SAW / Study of acoustic properties of TiO2 films with help of surface acoustic wave resonators
This thesis presents the study and design of the elements which compose a gas sensor based on Surface Acoustic Wave technology, such as, SAW Colpitts oscillator and the SAW one-port resonator that are presents in the feedback loop of an amplifier. It was done deposition of TiO2 thin film different thickness on the sensor, in order to study the effect of SAW
Publicado em: 2005
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9. Tecnologia de sementes para quartzo sintetico : aprimoramento da perfeição cristalina
The advanced industry of information technology has been utilizing a large amount of synthetic quartz for electronic devices, such as resonators, wave filters, oscillators, SA W (Surface Acoustic Waves) devices. One important condition for these applications is the high perfection of synthetic quartzo Therefore, the progress of this area is closely related w
Publicado em: 2000
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10. Desenvolvimento de um filtro passa-faixas empregando tecnologia de ondas acusticas superficiais
The main objective of this work was to present the development of 70 MHz Bandpass filter, making use of Surface Acoustic Waves(SAW) technology. Some devices have been constructed in order to be used in the system to transmite TV signal by Fiberoptic, "TVFO". These devices were developed at the Brazilian Telecommunication Research an Development Centre (CPqDT
Publicado em: 1997
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11. Cerebellum mediates modality-specific modulation of sensory responses of midbrain and forebrain in rat.
Evidence of a sensory role of the cerebellum, mediating a modulation of effectiveness of afferent input at other parts of the brain, has been reported previously for certain sense modalities but has not been evaluated across several in a mammal. After a conditioning train of stimuli applied to the cerebellar surface in unanesthetized rats, diffuse flashes, a