Fig. 2. (a) Relative errors in volumetric heat capacity (C, filled symbols) and thermal diffusivity (k, hollow symbols) that occur when the model of Bristow et al. (1994) (Eq. [19–20]) is used to compute k and C rather than the model with zero surface temperature (ZST) boundary conditions (Eq. [15]). (b) Enlargement of the highlighted rectangular area of (a). Probe spacings are r = 2, 3, 4, 5, and 6 mm.