Ultrasonic Signals
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. Comparative study of periodicity estimation methods using ultrasonic signals
Abstract Introduction Various signal-processing techniques have been proposed to extract quantitative information about internal structures of tissues from the original radio frequency (RF) signals instead of an ultrasound image. The quantifiable parameter called the mean scatterer spacing (MSS) can be useful to detect changes in the quasi-periodic microstr
Res. Biomed. Eng.. Publicado em: 09/09/2016
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3. Assessment of cumulative damage by using ultrasonic C-scan on carbon fiber/epoxy composites under thermal cycling
In recent years, structural composites manufactured by carbon fiber/epoxy laminates have been employed in large scale in aircraft industries. These structures require high strength under severe temperature changes of -56° until 80 °C. Regarding this scenario, the aim of this research was to reproduce thermal stress in the laminate plate developed by temper
Materials Research. Publicado em: 19/06/2012
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4. On the relationships between ultrasonic calling and anxiety-related behavior in rats
In the present review, the phenomenon of ultrasonic vocalization in rats will be outlined, including the three classes of vocalizations, namely 40-kHz calls of pups, and 22- and 50-kHz calls of juvenile and adult rats, their general relevance to behavioral neuroscience, and their special relevance to research on anxiety, fear, and defense mechanisms. Here, t
Brazilian Journal of Medical and Biological Research. Publicado em: 2012-04
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5. Reconhecimento de PadrÃes AtravÃs de AnÃlises EstatÃsticas e Fractais Aplicadas a Dados de Ensaios NÃo-Destrutivos / Pattern Recognition by Statistical Fluctuation and Fractal Analyses Applied to Nondestructive Testing Data
In this work a procedure is studied for pattern classification related to different types of data, namely: (1) signals obtained from ultrasonic testing ( pulse-echo technique) and magnetic signals obtained from BarkhÃusen noise in samples of ferritic-pearlitic carbon steel tubes which, due to temperature effects, have shown microstructural changes as conseq
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 19/12/2011
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6. Simultaneous measurements of the solid particles velocity and concentration profiles in two phase flow by pulsed ultrasonic doppler velocimetry
In this experimental study, the pulsed ultrasonic Doppler velocimetry was used to measure simultaneously the local velocity and the local concentration in a flow of solid-liquid suspension in a horizontal pipe. In order to distinguish between the Doppler signals coming from the continuous phase, water and those of the glass bead particles larger than the Kol
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2009-12
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7. Sistema multicanal de geração e recepção de ondas ultra-sonicas para transdutor matricial linear / Multichannel system for generation and detection of ultrasonic waves with a linear array transducer
Ultrasound in medicine has gone through great evolution in the last few decades and has occupied important position as a tool for therapy and diagnosis. This is due to the ultrasound equipment be of relatively low-cost, ultrasound is a non-ionizing radiation, is a non-invasive imaging method, and the images are created and seen in real time. It is common the
Publicado em: 2006
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8. The use of artificial neural network in the classification of pulse-echo and TOFD ultra-sonic signals
The present work evaluates the application of artificial neural networks for pattern recognition of ultrasonic signals using pulse-echo and TOFD (Time of Flight Diffraction) techniques in weld beads. In this study pattern classifiers are implemented by artificial neural network of backpropagation type using MATLAB®. The ultrasonic signals acquired from puls
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2005-12
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9. Desenvolvimento de sistema de sensoriamento de posição e atuação para posicionamento dinâmico de modelos reduzidos em tanque de provas. / Development of both sensing and actuation infra-structure for the performance evaluation of Dynamic Positioning Systems for reduced scale model of ships in towing tanks or offshore tanks.
The main objective of this work is the development of both sensing and actuation infra-structure for the performance evaluation of Dynamic Positioning Systems for reduced scale model of ships in towing tanks or offshore tanks. It describes the conception, design, implementation and tests of a range and orientation sensor system, as well as the hardware of th
Publicado em: 2005
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10. Medição de múltiplas fases de nível de líquidos usando filtro adaptativo: técnicas, métodos e simulações / Measurement of multiple phases of level of liquids using adaptativo filter: techniques, methods and simulation
A medição de nível, além das aplicações em reservatórios de processos industriais, como nas indústrias químicas, farmacêuticas, petroquímicas, de refino de alumina etc., é aplicável também em reservatórios expostos ao ar livre, tais como diques, lagos e lagoas, barragens e outros. Medir nível na maioria dos casos tem grande impacto na seguran
Publicado em: 2005
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11. CaracterizaÃÃo de Defeitos de Soldagem atravÃs da AnÃlise Fractal de Sinais Ultra-SÃnicos Obtidos pela TÃcnica TOFD / Characterization of Weld Defects by Fractal Analysis of Signals Obtained by Ultrasonic TOFD Technique
O presente trabalho tem como objetivo caracterizar diferentes defeitos de soldagem ( falta de fusÃo, falta de penetraÃÃo e porosidade) inseridos em corpos de prova durante o processo de soldagem, atravÃs da anÃlise fractal di sinais ultra-sÃnicos obtidos pela tÃcnica TOFD. Para eliminar os ruÃdos, os sinais foram tratados usando dois mÃtodos de filt
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 28/10/2004
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12. Universalidade e leis de escalas em amostras de silicio atacadas quimicamente
Morphology of etched Si surface has been investigated by atomic force microscope (AFM). Samples were etched by NaOH solution in distinct experimental condictions. Linear relationships were observed in log-log plots of height fluctuation ( D h ) versus length variation ( D l ), where the roughness exponent ( a ) is obtained from the slope. Growth exponent (b)
Publicado em: 2003