نتایج جستجو برای: ultrasonic parameters

تعداد نتایج: 604637  

Journal: :Ultrasound in medicine & biology 2008
Hairong Shi Tomy Varghese Robert J Dempsey Mohammed S Salamat James A Zagzebski

Many ultrasonic parameters, primarily related to attenuation and scatterer size, have been used to characterize the composition of atherosclerotic plaque tissue. In this study, we combine elastographic (axial strain ratio) and ultrasonic tissue characterization parameters, namely the attenuation coefficient and a scattering parameter associated with an "equivalent" scatterer size to delineate b...

2013
Mitul Kumar Mishra Shobha Prakash

BACKGROUND AND OBJECTIVES Scaling and root planing is one of the most commonly used procedures for the treatment of periodontal diseases. Removal of calculus using conventional hand instruments is incomplete and rather time consuming. In search of more efficient and less difficult instrumentation, investigators have proposed lasers as an alternative or as adjuncts to scaling and root planing. H...

2007
R. Kažys L. Mažeika E. Žukauskas

The modern aircrafts are built using various composite materials such as carbon/glass fibre reinforced plastics, GLARE and honeycombs. Manufacturing technologies of composite materials are complicated and include many stages. Small deviations from the technology parameters may cause relatively small defects, but influence of these defects on a total strength of a construction may be essential. ...

Low transmission of heat is one of the major problems for heat exchanger fluids in many industrial and scientific applications. This includes cooling of the engines, high power transformers to heat exchangers in solar hot water panels or in refrigeration systems. In order to tackle these problems in thermal industries, nanofluids could play a significant role as excellent heat exchanger materia...

2003
Patrick H. Johnston Kendall R. Waters

A method is presented based on tomographic reconstruction techniques for the visualization of an ultrasonic field. The tall, narrow piezoelectric elements of a one-dimensional receiving array, rotated about its central axis, provide parallel projection input data for tomographic reconstruction of the field. The technique is demonstrated using simulated ultrasonic beams and experimental measurem...

2017
Feng Li Aun Raza Yan-Wei Wang Xiu-Quan Xu Guan-Hua Chen

BACKGROUND Rattan tea is a medicinal plant that has been used for many years for the treatment of inflammation, fatty liver, tumor, diabetes, and hyperlipidemia. OBJECTIVE A green and novel approach based on surfactant-mediated, ultrasonic-assisted extraction (SM-UAE) was developed for the extraction of antioxidant polyphenols from Rattan tea. A nonionic surfactant Tween-80 was selected as ex...

In this paper, an experimental investigation on ultrasonic welding of polyamide composites reinforced with glass fiber has been carried out. The effect of ultrasonic welding parameters, such as welding time, air pressure, hold time and the amount of glass fiber in the composite on tensile strength of weld joints were determined using response surface methodology. This methodology was applied fo...

The present study introduces two quantitative parameters to compare the accuracy of ultrasonic C-scan testing and X-ray radiography methods in the damaged area detection under low-velocity impact in polymer-based composites. For this purpose, the hand lay-up technique of composite processing was employed to prepare the composite specimen. A composite specimen consisting of the glass fiber reinf...

2012
Pawel Fabijanski Ryszard Lagoda

This chapter is dedicated to ultrasonic piezoelectric ceramic power transducers. These elements are now the most popular source of high power ultrasound and is used in many industrial applications. High power ultrasonic waves are generally used in such industrial processes as welding, acceleration of chemical reactions, scavenging in gas medium, echo sounding and underwater communication (sonar...

2014
Pavel Mares

Ultrasonic testing is a very important non-destructive method for testing components for safety of nuclear power plants and other security and delicate parts in other industries. Nowadays, thanks to the development of computer technology, it is possible to simulate processes which occur during ultrasonic testing. That is why numerical simulations are becoming an integral part of non-destructive...

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