Acoustic Sensors
Mostrando 1-12 de 18 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. ACOUSTIC ENVIRONMENT AND GAS PRODUCTION IN DIFFERENT GROWING-FINISHING SWINE FACILITIES
ABSTRACT This study aimed to evaluate gas levels and the acoustic environment (noise) of growing-finishing swine in different facilities, one composed of shallow pool (SP) and another of partially slatted floor (PSF). Sensors and a sound level meter were used to measure gas concentrations (CO2 and NH3) and noise at 1.50 meters above the ground and at animal
Eng. Agríc.. Publicado em: 2016-12
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3. MONITORING FLEXIBLE RISERS WITH OPTICAL FIBER SENSORS / MONITORAMENTO DE RISERS FLEXÍVEIS COM SENSORES A FIBRA ÓPTICA
The interest in structural health monitoring of flexible risers has grown significantly in recent years. For ducts that are already reaching their design life, monitoring systems can provide early warnings of potential failures and also assist the operator in scheduling downtime. Different techniques are being tested by operators of flexible pipes such as au
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 07/04/2011
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4. 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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5. 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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6. Ruido Barkhausen y emisión magneto acústica para la caracterización de materiales ferromagnéticos
The techniques of Barkhausen Noise (BN) and Magneto Acoustic Emission (MAE) were applied to a ferromagnetic material with the objective of correlating the obtained signals with the micro structural changes. The first step was the development of an Integral Measurement System (IMS) for the BN and MAE signals. Different devices as magnetic yoke, current source
Matéria (Rio de Janeiro). Publicado em: 2008-03
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7. Monitoring of operations the rectification using sensors of fusion / Monitoramento de operações de retificação usando fusão de sensores
The present study deals with an experimental analysis of a monitoring system based on a sensor fusion strategy applied to a cylindrical grinding machine. It comprises a fusion of the power and acoustic emission signals and has as main goal to obtain the FAP (Fast Abrasive Power) using the method developed by Valente (2003). Initially, the power and acoustic
Publicado em: 2007
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8. Modelagem endoscÃpica virtual do monitoramento de equipamentos elÃtricos de alta tensÃo
With the promulgation of the 10.847/2004 and 10.848/2004 Laws, the Brazilian Power Sector started adopting competitiveness as the main element for obtaining concessions in the electric power system transmission and generation sectors. In this sense, the power sector companies will have to strongly intensify the monitoring processes of the power system equipm
Publicado em: 2007
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9. Controle ativo de ruído para transformadores de potência em campo. / Active noise control of power transformers in field.
É cada vez maior a preocupação com a poluição sonora gerada pelos transformadores de potência de subestações elétricas. Atualmente, o controle desse tipo de ruído é feito utilizando-se métodos passivos, que são caros e dificultam a manutenção dos transformadores. Uma alternativa para os métodos passivos é o controle ativo de ruído (ANC). Ap
Publicado em: 2007
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10. Um middleware reconfigurÃvel para redes de sensores sem fio
The WSN attractivity for environment conditions monitoring and to be the bridge between the physical and virtual world has been increasing due to the advances in the micro-electronics, which enabled the production of several sensor types like illumination, humidity, temperature, smoke, radiation, acoustic, seismic, etc. in a chip that processes the signal an
Publicado em: 2006
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11. Determinação de parametros de qualidade da gasolina e estudo de contaminantes utilizando espectros do infravermelho proximo na fase vapor
A near infrared based on an acoustic optic tunable filter (AOTF) was constructed for spectra acquisition of gasoline in the vapor phase. The measuring system of the instrument was composed by a detection cell and a sample cell, where temperature sensors were adapted to monitor the temperature of the gasoline vapor and the temperature of the silicone bath use
Publicado em: 2005
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12. Compact SPICE model for devices and sensors based on surface acoustic wave / Modelo SPICE compacto para dispositivos e sensores a onda acÃstica de superfÃcie
O desenvolvimento atual em sensores tem como objetivo, uma maior integraÃÃo entre o componente sensÃvel e o circuito eletrÃnico para detecÃÃo, processamento e comunicaÃÃo, de maneira que todos os componentes sejam fabricados no mesmo chip. Esse tipo de sensor à denominado genericamente de sensor inteligente integrado (integrated smart sensor). A sua
Publicado em: 2002