An alternative approach for measuring yield stress and its application in Carbopol microgel

Abstract An innovative experimental apparatus for the direct measurement of yield stress was conceived and realized. It is based on a torsion pendulum equipped with magnetic dipole rotating cylinder immersed in material to be investigated. The equilibrium state depends mechanical torque applied due an external induction field, elastic reaction suspension wire, shear stress. Experimental results are reported showing that behavior rotation angle, different conditions, provides evidence presence enables its evaluation by equations. dependence time approach also studied, contributing shed light relaxation effect transition from fluid-like solid-like behavior, as well eventual thixotropic effects non-Newtonian fluids. validity proposed technique related tested aqueous Carbopol solutions, weight percentages. linear procedure, combined effectiveness reliability method, candidates it used study peculiar behaviors other complex fluid such blood, crude waxy oils, ice slurries, coating layer food industry fault sliding geodynamics.