Acoustic levitation technique for containerless processing at high temperatures in space

Acoustic levitation: recent developments and emerging opportunities in biomaterials research

“…Barmatz et al (1985) developed resonant acoustic cavities to create regions that can trap small samples. Interference acoustic levitators were pioneered by Whymark (1975) and Rey et al (1987) and further developed in the US (Trinh 1985), Europe (Lierke et al 1983), and Asia (Xie and Wei 2001). Simple interference levitators comprise a single transducer and an opposed reflector.…”

“…Simple interference levitators comprise a single transducer and an opposed reflector. Shaping of the transducer radiator and/or the reflector can focus the sound field to produce a stronger radial restoring force (Rey et al 1987). The transducer-reflector arrangement enables stable levitation but it does not enable manipulation of the sample.…”

Nucleation kinetics of continuously cooling Fe–17at.%B droplets produced by controlled capillary jet breakup

“…Electromagnetic levitation methods, in which a relatively large levitated droplet, usually a few millimeters in diameter, is allowed to undergo a large undercooling, were used by Piccone et al (1987) for Ni-Sn droplets and by Suzuki et al (1991) for Ni-P droplets. Rey (1988) used an acoustic levitation technique to investigate alloy droplet solidification in space. Long and short tube methods, where droplets are solidified during their free fall, were used by Drehman and Turnbull (1981) to study the nucleation of Pd-Si droplets, by Lacy et al (1981Lacy et al ( , 1982 and Evans et al (1986) to investigate the solidification of Nb-Ge droplets, and by Vinet and Cortella (1994) to determine the solidification pathways of Ta alloy droplets.…”

Particle manipulation by a non-resonant acoustic levitator

“…16,17 In a typical single-axis acoustic levitator, the standing wave is formed by the multiple wave reflections that occur between the transducer and the reflector. In the non-resonant levitator, the standing wave is mainly formed by the superposition of two waves: the emitted wave by the transducer and the first reflected wave.…”

“…There are different forms of reducing the amplitudes of the high-order reflections in order to obtain a nonresonant device, such as minimizing the transducer reflection coefficient, 20 reducing the reflector size, 16,17 or by producing two sound beams that are not reflected by the opposite transducers. 19 In the present device, high-order reflections are minimized through the reduction of the transducer radius and by limiting the minimum separation distance between the transducer and the reflector to d ¼ 50 mm.…”