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Convection-cooling is sometimes loosely assumed to be described by Newton's law of cooling. [6] Newton's law states that the rate of heat loss of a body is proportional to the difference in temperatures between the body and its surroundings while under the effects of a breeze. The constant of proportionality is the heat transfer coefficient. [7]
A correction to Newton's law concerning convection for larger temperature differentials by including an exponent, was made in 1817 by Dulong and Petit. [5] (These men are better-known for their formulation of the Dulong–Petit law concerning the molar specific heat capacity of a crystal.)
Simplified control circuit of human thermoregulation. [8]The core temperature of a human is regulated and stabilized primarily by the hypothalamus, a region of the brain linking the endocrine system to the nervous system, [9] and more specifically by the anterior hypothalamic nucleus and the adjacent preoptic area regions of the hypothalamus.
Physiology: Newborns lack the ability of thermogenesis due to underdeveloped shivering mechanism. Body heat is lost through conduction, convection, and radiant heat. [1] Thermoregulation is achieved through several methods: the metabolism of brown fat and Kangaroo care, also known as skin to skin.
Convective heat transfer, or simply, convection, is the transfer of heat from one place to another by the movement of fluids, a process that is essentially the transfer of heat via mass transfer. The bulk motion of fluid enhances heat transfer in many physical situations, such as between a solid surface and the fluid. [10]
The term radiative cooling is generally used for local processes, though the same principles apply to cooling over geological time, which was first used by Kelvin to estimate the age of the Earth (although his estimate ignored the substantial heat released by radioisotope decay, not known at the time, and the effects of convection in the mantle).
Several studies have shown that for uncovered infants, lined hats significantly reduce heat loss and thermal stress. [ 54 ] [ 55 ] [ 56 ] Children have a larger surface area per unit mass, and other things being equal should have one more layer of clothing than adults in similar conditions, and the time they spend in cold environments should be ...
Perinatal asphyxia is the medical condition resulting from deprivation of oxygen to a newborn infant that lasts long enough during the birth process to cause physical harm. [163] Hypoxic damage can also occur to most of the infant's organs ( heart , lungs , liver , gut , kidneys ), but brain damage is of most concern and perhaps the least ...