where J j is the flux of salt, D is the diffusion coefficient of salt (1.61 × 10 -9 m 2 /s), and c j is the concentration of component j. The initial NaCl concentration throughout the capillary was 4.5 mM, with boundary conditions applied such that the interface at one end was fixed at 0 mM, and there was no flux across any other interfaces. The numerical solutions were calculated for 96 hours at 15-minute intervals. Energies in Fig. were computed by converting the salt concentration at a given position and time to a λ D in meters using the formula,