Orientation of Fibers in Liquid by Ultrasonic Standing Waves

Yamahira, Syojiro; Hatanaka, Shin–ichi; Kuwabara, Mamoru; Asai, Shigeo

doi:10.1143/jjap.39.3683

Cited by 47 publications

(51 citation statements)

References 11 publications

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“…Cold model experiments 74) revealed that rod-like fibers shorter than one-fourth of the wavelength are constrained at the pressure node and are oriented in the direction perpendicular to that of wave propagation. On the other hand, fibers ranging from one-fourth to one-half of the wavelength were oriented either parallel to the direction of wave propagation at the pressure loop or perpendicular to that at the pressure node depending on their initial positions and directions.…”

Section: Ultrasonically Assisted Designing Of Compositementioning

confidence: 99%

High Power Ultrasonics in Pyrometallurgy: Current Status and Recent Development

2005

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In recent years, a large number of studies have been published on the use of high intensity ultrasonics in various high temperature technologies. This paper provides an overview of the recent achievements and ongoing works on the application of high intensity sound waves to pyrometallurgy and its related areas. The published results have strongly suggested that ultrasonics has the potential to play a more significant role in such areas as the dedusting of high-temperature exhaust gas, improvement of fuel-combustion efficiency, control of air-pollutant emissions, improvement of the quality of ingots, production of metal powders and ascast composite materials.At higher temperatures, special attractiveness of sound waves is associated with the fact that the waves can propagate through gas, liquids, and solids, and thus supply the acoustic energy from a cooled sonic generator to materials being processed under high temperature conditions. This provides a unique tool, for example, for controlling the rates of interfacial phenomena that is unachievable by any other methods under high temperatures.Industrial competitiveness of the ultrasonic-based technologies is reinforced by the relatively low cost of power-generating equipment and ultrasonic transducers. However, further research efforts are called for to develop new heat-resistant waveguide materials and to integrate the ultrasonic installations with existing industrial facilities in high temperature technologies.KEY WORDS: pyrometallurgy; high temperature; sonoprocessing; high power ultrasonics; non-linear phenomena; air pollutants; continuous casting; melt atomization; cast composites.applications have been summarized in a book by one of the authors of the present review. 4)The following two circumstances make ultrasonics especially applicable to high-temperature technologies: 1) There is a severely limited choice of techniques available for supplying energy under conditions involving higher temperatures. Among these techniques, sonic/ ultrasonic treatment or sonoprocessing should be competitive as regards both technique and cost, because it provides an effective transmission of acoustic energy from the ultrasonic generators to the materials being processed at a relatively low cost for ultrasonic equipment. 2) It is well-known that interfacial phenomena play an important role in governing many high-temperature processes. Examples are mass and heat transfer, crystal growth during the solidification of liquid metals, wetting, and emulsification. Sonic and ultrasonic waves propagate through homogeneous elastic mediums without significant losses. However, when the waves are incident upon an interface, the scattering or reflecting or of the waves from the interface is responsible for a number of nonlinear phenomena that occur at the interfaces. These provide a unique tool for controlling the rates of interfacial phenomena. Such a tool is unachievable by any other methods. Along with improvements in the earlier methods of sonoprocessing, a number of new ultrasonic appl...

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Section: Ultrasonically Assisted Designing Of Compositementioning

confidence: 99%

High Power Ultrasonics in Pyrometallurgy: Current Status and Recent Development

2005

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“…This time-averaged torque is the underlying principle of the noncontact rotational manipulation, which has been applied to control the orientation of fibers in a fiber-reinforced composite 1 and in a paper pulp. 2 King studied the case of a circular disk in a plane progressive or stationary sound field.…”

Section: Introductionmentioning

confidence: 99%

Acoustic radiation torque on an irregularly shaped scatterer in an arbitrary sound field

Fan

Mei

Yang

et al. 2008

The Journal of the Acoustical Society of America

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To eliminate the limitation of the conventional acoustic radiation torque theory, which is only applicable to a disklike scatterer in a plane sound field, a new theory is established to calculate the radiation torque on any irregularly shaped scatterer in any arbitrary sound field. First, with the aid of the conservation law of angular momentum, the acoustic radiation torque is expressed as the angular momentum flux through a spherical surface with the center at the scatterer's centroid. Second, the velocity potential of the scattered field is derived, taking into account the influences of the translational and rotational movements of the scatterer induced by the first order stress of the incident sound field. Finally, a general calculating formula of the acoustic radiation torque is achieved. For a disklike scatterer in a plane sound filed, results from the above formula are well identical with those conventional formulas. By studying the case of a semicircular cylinder scatterer in a standing-wave sound field, it is found that for an irregularly shaped scatterer its rotation velocity is normally nonzero and the radiation torque changes with the spatial attitude.

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“…The fiber will always align with the direction of the potential well. The torque on a fiber can be evaluated by modeling the fiber as a chain of spheres as shown by Yamahira et al 23 For a cavity surrounded by hard boundary walls the different possible pressure modes with their corresponding potential force fields can be calculated. A single mode excited inside the cavity can be expressed as (m,n), where the first variable stands for the number of nodes of the pressure wave in the x-direction and the second variable stands for the number of nodes in the y-direction.…”

Section: Theorymentioning

confidence: 99%

“…23-25. Yamahira et al 23 studied the behavior of polystyrene fibers in a one-dimensional standing wave. The application is the directional control of reinforcing fibers in composite materials.…”

Section: Introductionmentioning

confidence: 99%

Rotation of non-spherical micro-particles by amplitude modulation of superimposed orthogonal ultrasonic modes

Schwarz

Petit-Pierre

Dual

2013

The Journal of the Acoustical Society of America

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Contactless rotation of non-spherical particles has been modeled and experimentally achieved using ultrasonic manipulation. For this purpose an acoustic radiation torque was generated by a time-varying pressure field resulting in a change of orientation of the potential well. The rotation method is based on amplitude modulation of two orthogonal ultrasonic modes. The force potential field has been used to evaluate the different modes and actuations to achieve rotation. Experiments have been performed in micro devices with copolymer particles and glass fibers at frequencies in the megahertz range. A continuous rotation was successfully demonstrated and the method allowed to stop the rotation at arbitrary angular positions.

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Orientation of Fibers in Liquid by Ultrasonic Standing Waves

Cited by 47 publications

References 11 publications

High Power Ultrasonics in Pyrometallurgy: Current Status and Recent Development

High Power Ultrasonics in Pyrometallurgy: Current Status and Recent Development

Acoustic radiation torque on an irregularly shaped scatterer in an arbitrary sound field

Rotation of non-spherical micro-particles by amplitude modulation of superimposed orthogonal ultrasonic modes

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