On the relaxation of volume and shear viscosities in vegetable oils

Ultrasonic behavior of edible oils: Correlation with rheology

“…Both the volume and shear processes require a much greater degree of cooperation. High frequency shear viscosity for castor oil has been measured by Mikhailov et al (5). Shear relaxation closely follows the volume relaxation, and the value of K does not change appreciably with frequency ( Fig.…”

“…That value of r/s; along with 60 = 95 MHz can be substituted in Eqn. [5] to give the second equation. With two equations and two unknowns, rt and r/~ can be calculated.…”

“…Ultrasonic attenuation has been studied over a wide range of frequency for some vegetable oils by Mikhailov et al (5), where an interesting attempt was made to link the ultrasonic attenuation with high frequency theology. Unfortunately, this work is clouded by the fact that the zero shear viscosities for castor oil and soy oil reported seem to be an order of magnitude greater than those reported by other well established sources (6,7).…”

“…However, the dependence of r/v/r/s upon frequency does vary with the nature of the molecule. For soy oil Mikhailov et al(5) found that r/v becomes negligible compared with r/s at "~90-100 MHz. Ultrasonic attenuation in all the oils studied (except castor oil) is similar to that in soy oil.…”