The pressure difference \(\Delta p\) across the @MT06878@, plug, etc., needed just to stop @E02019@. \(\Delta p\) is positive if the higher pressure is on the high potential side.
Source: PAC, 1972, 31, 577. (Manual of Symbols and Terminology for Physicochemical Quantities and Units, Appendix II: Definitions, Terminology and Symbols in Colloid and Surface Chemistry) on page 620 [Terms] [Paper]