Topic
Acoustic interferometer
About: Acoustic interferometer is a research topic. Over the lifetime, 1493 publications have been published within this topic receiving 19355 citations.
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TL;DR: In this article, the authors measured the strain amplitudes of 10 Mc/sec sound waves in solids under conditions in which standing waves were set up, as well as under pulsed conditions.
Abstract: The strain amplitudes of 10 Mc/sec sound waves in solids were measured under conditions in which standing waves were set up, as well as under pulsed conditions. The methods used were (1) measuring the equivalent electrical resistance of the transducer, (2) measuring the heating produced by absorbing the sound waves, (3) diffraction of light from standing acoustic waves, and (4) the changes in a nuclear magnetic‐resonance‐absorption signal produced by the sound waves. All these methods were in substantial (±20%) agreement with one another. Measurements with different characteristics for the coupling between the transducer and sample showed the importance of this thin film. The highest strain amplitudes were obtained at frequencies slightly higher than the quartz‐transducer resonant frequency. Even higher strains could be obtained with coupling films approximately 14‐wavelength thick.
11 citations
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TL;DR: Reflection of ion acoustic waves from a bipolar potential structure was studied in a double plasma device as discussed by the authors, and the existence of a reflected signal, even when no external bias was applied on the bipolar reflector, could be detected, although with much lower velocity than the incident wave.
Abstract: Reflection of ion acoustic waves from a bipolar potential structure was studied in a double plasma device. The existence of a reflected signal, even when no external bias was applied on the bipolar reflector, could be detected, although with much lower velocity than the incident wave. Application of proper bias on such a reflector resulted in an additional reflected image with greater velocity than the reflection obtained without bias. The experiment was also extended to study negative ion plasma waves.
11 citations
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TL;DR: In this paper, a liquid-filled acoustic transducer for finishing an exposed surface of a work medium, such as plastic concrete, transmits acoustic energy generated within an enclosed liquid medium, through a transducers housing member, and into the exterior work medium.
Abstract: A liquid-filled acoustic transducer for finishing an exposed surface of a work medium, such as plastic concrete, transmits acoustic energy generated within an enclosed liquid medium, through a transducer housing member, and into the exterior work medium. Acoustic waves are generated by electrically-actuated liquid-immersed piezoelectric elements housed within the device. The efficiency with which acoustic waves are transmitted from the interior of the device to the adjacent work medium is enhanced by providing an intermediate transducer housing member, disposed between the liquid in which the piezoelectric elements are immersed and the work medium, having acoustic impedances at its two major surfaces matching the respective acoustic impedances of the respective interfacing media and a continuous acoustic impedance gradient between those two surfaces.
11 citations
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TL;DR: In this article, the authors measured the speed of sound of the gaseous trifluoroiodomethane (CF3I) for temperatures from 273.15 to 333.15 K and pressures from 58 to 276 kPa with a cylindrical, variable-path acoustic interferometer operating at 156.252 kHz.
11 citations
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TL;DR: In this article, a method for determining the losses in a rocket chamber during (combustion instability) is proposed based on acoustic measurements at room temperature, which permits the losses to be determined from experiments in a small-scale model of the actual chamber.
Abstract: A promising method for determining the losses in a rocket chamber during (combustioninstability is based on acoustic measurements at room temperature. This method permits the losses to be determined from experiments in a small-scale model of the actual chamber. The calculations presented here treat the acoustics of a chamber with mean flow; they are intended to be used in the design of such experiments and in the interpretation of data.
11 citations