نتایج جستجو برای: ultrasonic

تعداد نتایج: 28251  

2017
H. R. Carleton W. J. Chen

The development of the mechanical strength of composite materials which are consolidated by cementaceous bonds has been monitored by observation of the ultrasonic properties over the evolution of bond growth. The granular nature and weak bonding of these materials produce high attenuation of the ultrasonic signal and observation is difficult, particularly in larger structures. In order to obtai...

2013
Junshan Gao Ke Wang Jingjing Sun

Ultrasonic testing is an important flaw detection technology in nondestructive testing field. With its unique electronic scanning, dynamic deflection focusing (DDF), sectorial scanning characters and ultrasonic phased array (UPA) technology can be used for defecting detection of objects with curved face or complex structure. Thus, UPA technology has become a focus of ultrasonic testing research...

2006
Adrian Cuc Victor Giurgiutiu

The nondestructive evaluation (NDE) of adhesively bonded structures is a complex process. Earlier work has confirmed that ultrasonic waves are influenced by the properties of the material in which they travel. Acousto-ultrasonic methods have been widely used by previous researchers to generate ultrasonic waves in plates and bonded structures for flaw detection, visualization, and measurements o...

Journal: :Journal of ultrasound in medicine : official journal of the American Institute of Ultrasound in Medicine 1986
E L Madsen G R Frank P L Carson P D Edmonds L A Frizzell B A Herman F W Kremkau W D O'Brien K J Parker R A Robinson

A set of test samples, all containing ultrasonically equivalent tissue-mimicking material, was produced and measurements of ultrasonic speed and ultrasonic attenuation coefficients were made at seven laboratories using various techniques. The ultrasonic speed values agree well with one another, having a spread of about 0.3 per cent; thus, speed values for tissue parenchyma appearing in the lite...

2016
Pedro Acevedo Carlos Díaz Mónica Vázquez Joel Durán

This paper describes the design of a pulse generator based on the Programmable System-on-Chip (PSoC) module. In this module, using programmable logic is possible to implement different pulses which are required for ultrasonic applications, either in a single channel or multiple channels. This module can operate with programmable frequencies from 3-74 MHz; its programming may be versatile coveri...

Journal: :journal of ultrafine grained and nanostructured materials 2012
m saeidi hossein sarpoolaky s. m. mirkazemi

recently, the al2o3–tio2–zro2 system has found valuable applications, particularly, as a support for nox storage–reduction (nsr) catalysts. nanocomposite powders were prepared from the co-precipitation method in inorganic precursors. the behaviors of mixed oxide nanoparticles under ultrasonic irradiation, such as dispersion, and crushing were studied. phase transformations, crystallite size, an...

2014
Liang Zhang Heming Hu Tao Meng Chi Wang

Experimental study of multi-path ultrasonic flowmeters measurement accuracy in complex flow fields was carried out in the water flowrate standard facility of National Water Large Flowrate Measurement Station. Several muti-path ultrasonic flowmeters with different path arrangement were studied. The flow disturbances were created by bend, tapered pipe, diverging pipe and butterfly valve. By study...

Journal: :The Journal of the Acoustical Society of America 1999
G Yao L V Wang

A simple method for imaging ultrasonic fields in clear media is introduced. A modulated laser source is used to project the ultrasonic field onto a CCD camera. By use of the source-synchronized lock-in detection scheme, 2D images of the amplitude and phase distributions can be determined simultaneously. This technique is experimentally demonstrated with a 1-MHz and a 3.5-MHz ultrasonic transduc...

2011
Qin Shen

This study investigates the different types of ultrasonic inspection, when applied to assess the impact damage in Carbon Fiber Reinforced Plastic CFRP laminates. The study surveys the two most used ultrasonic testing approaches first; namely the pulse-echo and the through-transmission modes. Then, the manuscript discusses and analyzes the enhanced ultrasonic testing methods that use the polar s...

2006
Will Almeida Bruno Costa Raimundo Freire Francisco Santos Sebastian Catunda

The fluids speed measurement, particularly the air speed measurement is very important for industrial and laboratory applications. The ultrasonic method is among the most common methods used for determining the air speed. The basic principle to measure a fluid speed, using an ultrasonic transducer, is based on the modification of the apparent propagation speed of an ultrasonic signal caused by ...

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