Photoacoustic
Mostrando 13-24 de 94 artigos, teses e dissertações.
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13. Dureza Brinell y parámetros termofísicos de la Guadua angustifólia - Kunth
Guadua angustifolia-Kunth is a forest resource with special physical and mechanical characteristics, which is used mainly in houses building, laminates manufacture, and decorative items. Also it plays an important role in watershed protection, in the CO2 capture and soil conservation. The thermal and mechanical characterization of this type of biological mat
Matéria (Rio J.). Publicado em: 2012
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14. Desenvolvimento de um sistema de detecção fotoacústico utilizando dois microfones: aplicações em medidas de difusividade térmica / Developing of a photoacoustic detection system using two microphones: applications in thermal diffusivity measurements
Neste trabalho, desenvolveu-se um sistema de detecção fotoacústico para medidas simultâneas e independentes dos sinais fotoacústicos dianteiro e traseiro, utilizando dois microfones e um único feixe de excitação. Utiliza-se a diferença de fase entre estes sinais para a determinação da difusividade térmica de materiais, com base na abordagem teór
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 06/09/2011
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15. Photoacoustic spectroscopy applied to glass transition temperature determination of polymers / Aplicação da espectroscopia fotoacústica na determinação da temperatura de transição vítrea de polímeros
Photoacoustic spectroscopy (PAS) is a non-destructive technique and it has been largely applied to the thermal and optical characterization of materials. PAS technique is based on the photoacoustic effect which consist, basically, absorption of a modulated electromagnetic radiation and generation of heat inside of the material studied (sample), by a nonradia
Publicado em: 2010
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16. Bombeamento optico com lasers de 13CO2 : espectroscopia de absorcao fotoacustica no infravermelho e de emissao laser no Terahertz em isotopos de metanol / Optical pumping with 13^Co_2 lasers: infrared photoacoustic absorption spectroscopy and Terahertz laser emission in methanol isotopes
Abstract
Publicado em: 2010
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17. 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
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18. A spectroscopic study of Au/CeX Zr1-X O2 catalysts
The nature of gold species in Au/CeX Zr1-X O2 catalysts was successfully investigated using the visible and near infrared photoacoustic spectroscopy and Fourier transform infrared spectroscopy of adsorbed carbon monoxide. It was found that the visible and near infrared photoacoustic spectroscopy is a powerful technique for investigating the changes of gold p
Brazilian Journal of Physics. Publicado em: 2009-04
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19. Investigação de propriedades magnéticas e ópticas de fluidos magnéticos biocompatíveis / Investigação de propriedades magnéticas e ópticas de fluidos magnéticos biocompatíveis
In this study static magnetic birefringence, photoacoustic spectroscopy and transmission electronic microscopy were used to investigate the dilution effect of dimercaptosuccinic acidcoated maghemite nanoparticles suspended as biocompatible magnetic fluids. The samples investigated have similar characteristics though presenting different surface grafting coef
Publicado em: 2009
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20. Construção, calibração e análise de desempenho de um piranômetro de baixo custo, baseado no modelo Kimball-Hobbs
In this work a pyrometer using the classic model of Kimball-Hobbs was developed, tested and calibrated. The solar radiation is verified through the temperature difference between the sensible elements covered by absorbing (black) and reflecting (white) pigmentations of the incoming radiation. The photoacoustic technique was used to optimize the choice of the
Publicado em: 2009
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21. Caracterização de ligas binárias nanoestruturadas dos sistemas Zn-Sb, Ge-Sb, Al-Sb e Co-Sb produzidas por síntese mecânica
Synthesis and study of nanostructured materials have generated great interest by the scientific point of view due to several new possibilities of technological applications. In this Doctoral thesis, nanostructured semiconductors with thermoelectric potential of Zn-Sb and Co-Sb systems, alloys of Al-Sb system and solid solutions of Ge-Sb system were produced.
Publicado em: 2009
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22. IMPLEMENTAÇÃO DA TÉCNICA DE FOTOACÚSTICA DE CÉLULA ABERTA PARA OBTENÇÃO DA DIFUSIVIDADE TÉRMICA DE METAIS
The photo-acoustic technique has become a standard photo-thermal method for carrying out diverse studies on solids materials. Photo-thermal phenomena in solids results from a combination of thermal expansion, thermal diffusion, and thermo-elastic bending effects and can be obtained by c k . r a = where k is the thermal conductivity, r is the density, and c i
Publicado em: 2009
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23. Thermal properties of WC-10 wt. (%) Co alloys
In this article, photothermal techniques were used in order to determine some thermal properties: diffusivity, conductivity, effusivity and specific heat capacity of WC-10 wt. (%) Co six samples subjected to different sintering processes. The samples were sintered using high pressure - high temperature (HPHT) sintering system. The open cell photoacoustic (OP
Materials Research. Publicado em: 2008-03
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24. Metodos baseados na fotoacustica para caracterização de materiais magnetocaloricos / Methods based on the photoacoustic for characterization of magnetocaloric materials
In this work the photoacoustic technique was used to develop experimental setups to investigate magnetocaloric materials, which have been of great interest due to their applications in refrigeration systems. The value (4,5 ± 0,2).10-6 m2/s was determined, at room temperature, as the thermal di usivity of the Gd, based on the two-beam photoacoustic method, b
Publicado em: 2008