The @S05638@ \(\sigma _{0}\) or \(\tau _{0}\) at which yielding starts abruptly. Its value depends on the criterion used to determine when yielding occurs.
Source: PAC, 1979, 51, 1213. (Terminology and Symbols in Colloid and Surface Chemistry Part 1.13. Definitions, Terminology and Symbols for Rheological Properties) on page 1217 [Terms] [Paper]