“…Although the agreement with experimental data was fairly good in case of metallic surfaces subjected to different types of machining (spark-machined, grit-blasted, sand-blasted surfaces, see, e.g., [6]), the applicability to textured surfaces should be a matter of discussion. This research is motivated by the fact that in the recent years we have seen a rise in designing and tailoring surface roughness in order to optimize adhesion in biological systems [22][23][24], capillary forces promoting the movement of liquids [25,26], thermal and electric contact conductance [18,19], frictional effects [20,27], wave transmission [28] and also light reflectance properties fundamental for high efficiency solar energy conversion [29]. In most of such cases, surfaces present complex textures over multiple scales, probably far beyond the capabilities of models based on the RPT and also not just simply fractals.…”