This layer forms the external pyramidal layer and is made up of small or medium pyramidal cells that follow a size gradient: Pyramids from superficial to deep portions of the layer increase progressively in size.
Furthermore, some skin thermoreceptors respond not to the temperature, but to the rate of temperature change (Hensel 1974), and there may also be a mechanism for detecting a spatial temperature gradient in the superficial skin layer (Slepchuk & Ivanov 1992).
The Earth's surface topography disturbs the thermal field making measured superficial thermal gradients (heat flow) higher or lower than the deep value.
This species and other teutophageous cetaceans (i.e. dwarf and pigmy sperm whales, pilot whales, Risso's dolphin, and Ziphiidae) occurred, over abyssal depths, at the steepest sea superficial temperature gradients, at the periphery of a cyclone zone and in a convergence zone, both forming thermal fronts because of the aggregation of main preys near these zones [34], [35].
This is inconsistent with recent experimental evidence that suggests that radiative heat transfer is significant, and that Darcy's law does not adequately describe the relation between superficial flux and gradient in rockfill materials.
Superficial velocity versus pressure gradient was measured and different onset values were reported.
At these velocities, the plot of superficial velocity vs. pressure gradient deviates from the linear relationship of the Darcy's law.
The use of increased sparger hole density at a constant gas superficial velocity leads to steeper gradient in the gas holdup near the column centerline and a higher overall gas holdup.
Interfollicular human epidermis consists of keratinocytes arranged in a spatial gradient of differentiation across the deep-to-superficial axis of the tissue (Fig. 1b).
In the current study, warm-up exercise increased Tmvl by 2.7, 3.2 and 3.3 °C for deep-, mid- and superficial-depths, respectively, reducing the temperature gradient across the three depths.
