Fig. 3. Theoretical dimensionless temperature responses versus water flux for continuous heating (filled circles), for a 15-s heat pulse using the maximum dimensionless temperature increase difference (MDTD) method (open circles), and for a 15-s heat pulse using the ratio method (filled triangles). Thermal conductivity was 1.5 W m^–1 K^–1, volumetric heat capacity was 2.5 MJ m^–3 K^–1, needle spacing was 6 mm, and for the continuous heating scenario dimensionless temperature increase difference after 3600 s is shown.