Acoustic Attenuation
Mostrando 1-12 de 20 artigos, teses e dissertações.
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1. 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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2. Evaluation of gloves as a water bag coupling agent for therapeutic ultrasound
Abstract Introduction Therapeutic ultrasound (TUS) is a widespread modality in physiotherapy, and the water bag technique is a coupling method employed in the presence of anatomical irregularities in the treatment area. The aim of the present study is to evaluate the acoustic attenuation of the water bag and its effectiveness as a TUS coupling agent. Metho
Res. Biomed. Eng.. Publicado em: 27/03/2017
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3. Realistic deformable 3D numeric phantom for transcutaneous ultrasound
Abstract Introduction Numerical phantoms are important tools to design, calibrate and evaluate several methods in various image-processing applications, such as echocardiography and mammography. We present a framework for creating ultrasound numerical deformable phantoms based on Finite Element Method (FEM), Linear Isomorphism and Field II. The proposed met
Res. Biomed. Eng.. Publicado em: 16/03/2017
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4. O papel da ultrassonografia na medida da gordura subcutânea e visceral e sua correlação com a esteatose hepática
Objective To evaluate the sonographic measurement of subcutaneous and visceral fat in correlation with the grade of hepatic steatosis. Materials and Methods In the period from October 2012 to January 2013, 365 patients were evaluated. The subcutaneous and visceral fat thicknesses were measured with a convex, 3–4 MHz transducer transversely placed 1 cm abo
Radiol Bras. Publicado em: 2013-10
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5. Implementation of acoustic materials to the VLS-1 Fairing - a sensitivity analysis using SEA
Satellite launchers are submitted to severe acoustic loads mainly during lift-off where SPL achieve, at the upper parts, values within the range of 140-160 dB. Such an excitation can damage embedded elements, if energy attenuation measures are not adopted. In view of managing the PLF vibro-acoustic environment, numerical techniques are applied to predict ela
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2012-03
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6. Avaliação da tensão superficial, parâmetros reológicos e atenuação acústica de suspensões de açaí / Analysis of surface tension, ultrasound attenuation and rheological parameters of açai\ suspensions
Nesta pesquisa teve-se como objetivo estudar as propriedades físicas de polpas de açaí disponíveis comercialmente, tais como: pH, condutividade, viscosidade, tensão superficial e atenuação acústica, em função da temperatura e de particulados presentes na suspensão de açaí. Foram selecionadas quatro marcas comerciais de polpa de açaí originári
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 14/10/2011
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7. The use of the ultrasound measurement technique for the evaluation of mechanical properties of the ASTM A36 steels
This work presents a study about the correlations between the characteristics of the acoustic waves and the mechanical properties of low carbon hot rolled steel bars, through the comparison between the wave velocity or attenuation and the tensile strength, yield point or elongation of the material. The aim is the possibility of using this technique to predic
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2011-06
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8. CFD and CAA analysis of single stream isothermal jets with noise suppression devices.
Since the 50 s, with the appearance of the turbojet engines, the jet noise is being exhaustively studied, because it is one of the most important source of aircraft noise. Many attempts have been made to reduce the jet noise, including higher by-pass turbofan engines. Chevron nozzles also have been used by the industry to try to reduce the jet noise with a l
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 13/04/2009
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9. Materiais e técnicas contemporâneas para controle de ruído aéreo em edifícios de escritórios: subsídios para especificações / Contemporaneous materials and techniques to air noise control on corporate edifices: specification foundations
Big cities have been taken the ground thought freeways and avenues, where constant and loud noise takes place. At theses ways, corporate edifices are also often established, so they naturally become exposed to the external noise interference, regardless the own internal facilities noising. The consequence is that people how work at these places are more pron
Publicado em: 2009
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10. ESTUDO DE ALVENARIAS E REVESTIMENTOS DE GESSO RECICLADO DESTINADO À HABITAÇÃO POPULAR / Study of masonry and Coatings made by Recycled plaster for low cost housing.
The generation of large quantities of solid waste is a great problem faced by urban areas. Like all building materials, the gypsum plaster is a generator of solid waste. The amount and inadequate waste disposal cause serious environmental, social and economical impacts. This requires the search for quick and effective solutions for its management, through th
Publicado em: 2008
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11. A methodology for noise prediction of turbofan engines.
A computional model is developed for prediction of noise emission from na existing or new turbofan engine. This model allows the simulation of noise generation from high bypass ratio turbofan engines, appropriate for use with computational programs for gas turbine performance developed at ITA. Analytical and empirical methods are used for spectrum shape, spe
Publicado em: 2006
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12. Aspectos fisiologicos e fisicos da orelha como emissora de sons / Physics and physiological aspects of the ear as a sound emitter system
Ear is the sound receptor in our body. Sound is captured and driven through external ear, amplified and modulated in middle ear and transduced to electrical sign in internal ear. However, otoacoustic emissions and objective tinnitus are examples of an inverse process, where ear can be a sound emitter. Trying to understand some of theses events, in which soun
Publicado em: 2006