Measurement of Change of Ultrasonic Waves Phase Due to Presence of Liquid on Reflective Surface (original) (raw)
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Reflection of ultrasonic waves at a liquid–cubic–solid interface
The Journal of the Acoustical Society of America, 1983
The results of numerical calculations are presented for the reflection coefficient of sound waves incident on a liquid-cubic-solid interface. The reflection coefficient is calculated numerically for the (001) face ofvarious cubic crystals. It is found that for certain orientations there is a null in the reflection coefficient. At this orientation all the power is coupled into a quasishear wave inside the solid. An explanation based on impedance theory is presented. The explanation given predicts that there might be reflection nulls for other liquid-solid interfaces where the solid is any anisotropic solid not just cubic. .20.Bi First boundary condition gives k'.r = ka.r = kL.r = k s"r = kS2.r, or J = 3,4,5. {21 at z----O k • =ka=k L =k s' =kS2=l•k X X X X X O• • ß =k•=k L =k s' =kS•=lyk where lx and ly are direction cosines of the incident wave. 435 J. Acoust. Soc. Am. 73 (2), February 1983 0001-4966/83/020435-06500.80
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Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 2005
An ultrasonic pulse incident on a lubricating oil film in a machine element will be partially reflected and partially transmitted. The proportion of the wave amplitude reflected, termed the reflection coefficient, depends on the film thickness and the acoustic properties of the oil. When the appropriate ultrasonic frequency is used, the magnitude of the reflection coefficient can be used to determine the oil film thickness. However, the reflected wave has both a real component and an imaginary component, and both the amplitude and the phase are functions of the film thickness. The phase of the reflected wave will be shifted from that of the incident wave when it is reflected. In the present study, this phase shift is explored as the film changes and is evaluated as an alternative means to measure oil film thickness. A quasi-static theoretical model of the reflection response from an oil film has been, developed. This model relates the phase shift to the wave frequency and the film p...
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ACOUSTIC PROPERTIES OF LIQUIDS, GASES, CERAMICS AND CRYSTALS UNDER THE INFLUENCE OF ULTRASONIC WAVES
In the study of material and characterization of their properties, our major concern is to invent various new materials and improvise the existing information about the known substances by developing in-depth understanding of physical and chemical properties corresponding to different physical conditions. For this certain important physical parameters such as adiabatic compressibility, specific acoustic impedance, relative association, intermolecular free length, relaxation time, free volume, Rao's constant, Wada's constant etc. are evaluated using ultrasonic velocity, density and viscosity of liquids, gases, ceramics and crystals.
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The Journal of the Acoustical Society of America, 1995
This paper presents two methods to measure the density of liquids based on the measurement of the reflection coefficient and propagation velocity, using a novel double-element transducer. The measurements can be made in liquids, stationary or in motion. The main factors that affect the precision of the measurements are analyzed. The effect of acoustic diffraction is eliminated by using the double-element transducer, where the receiver is somewhat larger in diameter than the emitter. The effect of short-and long-term stability of the electronics and piezoelectric ceramics employed in the system is also eliminated. A system was implemented and measurements of several liquids, stationary and in motion, were conducted.
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Proceedings of the 20th IEEE Instrumentation Technology Conference (Cat. No.03CH37412), 2003
Rapid, on-line determination of particle size and concentration is required for the efficient process measurement and control of many processes in government and industrial applications such as waste remediation for the Department of Energy sites and process control for chemical and pharmaceutical manufacturing. However, existing methods based on ultrasonic attenuation can become inaccurate for highly concentrated suspensions due to careful transducer alignment and the complicated mathematics required to describe multiple scattering, which controls the attenuation. Two measurements that help to overcome these difficulties are the ultrasonic backscattering and diffuse field. Backscattering is attractive because the single scattering theories typically used to describe backscattering are mathematically simpler than attenuation theories and lend themselves to more stable inversion processes. Also, the measurements of backscattering and diffuse fields do not require long travel distances and can be made with a single transducer thus eliminating alignment problems. We will present ultrasonic measurements on solid liquid suspensions designed to elucidate the particle size and concentration at high concentrations.
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1995
ABSTRACT A novel technique for amplitude measurements of acoustic field by light reflection at the free surface of a liquid is presented. The motion of the boundary layer of the liquid induced by the acoustic pressure, modulates the phase of a collimated laser beam. This phase modulation is observed using dark-ground techniques, and it gives a measurement of the acoustic power as function of the position. Experiments with piezocomposite 1-3 transducers were carried out. The technique presented is able to give quantitative information quickly about the motion of individual ceramic rods of the piezocomposite, and allows fast quality control for piezocomposite 1-3 transducers. We achieved a lateral resolution of 0.2×0.4 mm. The theoretical limit for the axial resolution is of the order of a few Angstroms
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Ultrasonics is the world's leading journal dedicated to the whole science and technology of ultrasound. Contributed material is welcomed in the following fields: elasticity, anelasticity and magnetoelasticity; ultrasonic sensors for process monitoring; nondestructive materials characterization; generation and detection of ultrasound; ultrasonic NDE and NDT; SAW devices; signal processing; acoustooptics; physics of ultrasound; ultrasonic wave propagation; ultrasonic visualization; ultrasonic microscopy; physics and technology of ultrasound in medicine and biology; high-power ultrasonics; actuators and motors; industrial ultrasonics; underwater ultrasonics.