Fig. 2. Measured breakthrough curve (BTC) with continuous time random walk/advection-dispersion equation (CTRW/ADE) fits for a Berea sandstone core; (dimensionless) flux-averaged concentration j vs. time t. Upper figure shows the complete BTC; lower figure focuses on the region identified by the bold-framed rectangle in the upper figure. Note the difference in scale units between the figures. Column length equals 0.762 m. Porosity n = 0.204. Flux q = 1.73 cm³ min^–1 (after Scheidegger's [1959] Fig. 2). Dashed line: best ADE model fit. Solid line: best CTRW fit.