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The Biot number (Bi) is a dimensionless quantity used in heat transfer calculations, named for the eighteenth-century French physicist Jean-Baptiste Biot (1774–1862). The Biot number is the ratio of the thermal resistance for conduction inside a body to the resistance for convection at the surface of the body.
For high voltage applications, a good dielectric gas should have high dielectric strength, high thermal stability and chemical inertness against the construction materials used, non-flammability and low toxicity, low boiling point, good heat transfer properties, and low cost. [1] The most common dielectric gas is air, due to its ubiquity and ...
Bismuth antimonides, Bismuth-antimonys, or Bismuth-antimony alloys, (Bi 1−x Sb x) are binary alloys of bismuth and antimony in various ratios.. Some, in particular Bi 0.9 Sb 0.1, were the first experimentally-observed three-dimensional topological insulators, materials that have conducting surface states but have an insulating interior.
Re-entry through the atmosphere generates very high temperatures due to compression of the air at high speeds. Insulators must meet demanding physical properties beyond their thermal transfer retardant properties. Examples of insulation used on spacecraft include reinforced carbon-carbon composite nose cone and silica fiber tiles of the Space ...
Bismuth telluride (Bi 2 Te 3) is a gray powder that is a compound of bismuth and tellurium also known as bismuth(III) telluride. It is a semiconductor, which, when alloyed with antimony or selenium, is an efficient thermoelectric material for refrigeration or portable power generation.
Thermal contact resistance is significant and may dominate for good heat conductors such as metals but can be neglected for poor heat conductors such as insulators. [2] Thermal contact conductance is an important factor in a variety of applications, largely because many physical systems contain a mechanical combination of two materials.
An example of a new source of heat "turning on" within an object, causing transient conduction, is an engine starting in an automobile. In this case, the transient thermal conduction phase for the entire machine is over, and the steady-state phase appears, as soon as the engine reaches steady-state operating temperature .
This colourless solid is an electrical insulator with a higher thermal conductivity than any other non-metal except diamond, and exceeds that of most metals. [12] As an amorphous solid, beryllium oxide is white. Its high melting point leads to its use as a refractory material. [13] It occurs in nature as the mineral bromellite.