Acoustic contrast factor

If the acoustic contrast factor A, 0, then a conventional FFF channel will enable normal and steric mode FFF separations to be carried out (Fig. la). 

Acousto-Physical Data of Relevant Blood Constituents, Showing a Sign Shift in the Acoustic Contrast Factor, for Erythrocytes versus Triglycerides... 

The acoustic contrast factor of the particles This last factor is a function of the differences... 

The equilibrium position, for this case (in which the particle is small compared to the acoustic wavelength), is independent of the size of the particle, but dependent upon the acoustic contrast factor and the strength and frequency of the ultrasonic field. This offers a means of characterizing the acoustic field, the pressure amplitude of which is often difficult to determine in microsystems, by balancing acoustic and gravitational forces on an acoustically levitated particle. Particles that are not neutrally buoyant will have a minimum acoustic energy density required to hold the particle against buoyancy forces. 

Due to the namre of the acoustic fields, the distribution of the particles will depend on the particle size and the compressibility and density of the particle relative to the fluid medium. Closer examination of the acoustic contrast factor shows that is may be negative (usually applicable to biological cells which are more compressible and less dense relative to the surrounding medium) or positive (as is in many inorganic and polymer colloids). Therefore, acoustic FFF (AcFFF) has tremendous potential in very clean separations of cells from other particles. One... 

By considering these factors, it can be seen that particles can be either all concentrated in one place, or by making use of the different size of particle populations and a competing force such as viscous drag, fractionated by size. It is also possible, by making use of acoustic contrast factor variations to fractionate similar sized populations. 

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