53 research outputs found
Solitary Dust--Acoustic Waves in a Plasma with Two-Temperature Ions and Distributed Grain Size
The propagation of weakly nonlinear dust--acoustic waves in a dusty plasma
containing two ion species with different temperatures is explored. The
nonlinear equations describing both the quadratic and cubic plasma
nonlinearities are derived. It is shown that the properties of dust--acoustic
waves depend substantially on the grain size distribution. In particular, for
solitary dust--acoustic waves with a positive potential to exist in a plasma
with distributed grain size, it is necessary that the difference between the
temperatures of two ion species be large that that in the case of unusized
grains.Comment: 16 pages, 6 figure
PVDF copolymer transducers used to evaluate microparticle suspensions
The ability of using high frequency ultrasonic transducers made from piezoelectric polymers, to characterize microparticle suspensions, has been investigated both in an experimental setup and in a numerical model. Both investigations, which consider microparticles settled on a glass substrate, show that the backscattered frequency spectra contain a number of minima values arising from wave resonances in the microparticles. The locations of these resonances are in the experiments, found to be independent of the particle concentration, but strongly dependent on the particle size. A comparison to previous results for floating microspheres, show that the material properties of the glass substrate, also has to be included for obtaining the correct resonance frequencies for settled particles
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