The Dynamic Motion of Pseudo-Sputum Mucin Solution on a Vibrating Plate

Abstract

The motion of pseudo-sputum (20% solution of mucin) on a vibrating plate has been investigated using a function generator and an amplifier. Many finger-like liquid columns have appeared at appropriate frequencies (100-130 Hz) from a droplet of the solution on a vibrating plate. The viscosity of the mucin solution was measured using a capillary viscometer of the Maron-Krieger-Sisko type, and it was shown that the shear-thinning viscosity occurred in the lower frequency region contrary to the fact that the most abnormal viscosity of the rheological dilatancy fluid emerges in higher frequency than the frequency in which it behaves the normal one; the most important mechanical cause of this soliton-like phenomenon or the emergence of fingerlike column and wrinkles on the surface of fluid is thought to be the rheological dilatancy (shearthickening viscosity) of source liquid. In connection with this vibrating liquid column phenomenon, the spectrums of productive cough were also investigated, and it was proved that the effective low frequency vibration, which is a characteristic spectrum of productive cough, is essential for the expectoration and is a similar mechanism to the above-mentioned pug mechanism of the finger-like liquid columns seen on the vibrating plate.