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Liquid nitrogen is a compact and readily transported source of dry nitrogen gas, as it does not require pressurization. Further, its ability to maintain temperatures far below the freezing point of water, specific heat of 1040 J ⋅kg −1 ⋅K −1 and heat of vaporization of 200 kJ⋅kg −1 makes it extremely useful in a wide range of ...
Liquid dielectrics are self-healing; when an electric breakdown occurs, the discharge channel does not leave a permanent conductive trace in the fluid. The electrical properties tend to be strongly influenced by dissolved gases (e.g. oxygen or carbon dioxide), dust, fibers, and especially ionic impurities and moisture. Electrical discharge may ...
Electrical breakdown in an electric discharge showing the ribbon-like plasma filaments from a Tesla coil.. In electronics, electrical breakdown or dielectric breakdown is a process that occurs when an electrically insulating material (a dielectric), subjected to a high enough voltage, suddenly becomes a conductor and current flows through it.
Liquid nitrogen. Nitrogen is a colourless, odourless, and relatively inert diatomic gas with a density of 1.251 × 10 −3 g/cm 3 (marginally heavier than air). It condenses to a colourless liquid at −195.795 °C and freezes into an ice- or snow-like solid at −210.00 °C.
For gases (e.g. nitrogen, sulfur hexafluoride) it normally decreases with increased humidity as ions in water can provide conductive channels. For gases it increases with pressure according to Paschen's law; For air, dielectric strength increases slightly as the absolute humidity increases but decreases with an increase in relative humidity [2]
Its thermal conductivity (2,200 W/m•K) is five times greater than the most conductive metal (Ag at 429); 300 times higher than the least conductive metal (Pu at 6.74); and nearly 4,000 times that of water (0.58) and 100,000 times that of air (0.0224). This high thermal conductivity is used by jewelers and gemologists to separate diamonds from ...
Its disadvantages include the cost of refrigeration of the wires to superconducting temperatures (often requiring cryogens such as liquid nitrogen or liquid helium), the danger of the wire quenching (a sudden loss of superconductivity), the inferior mechanical properties of some superconductors, and the cost of wire materials and construction. [2]
To keep the helium from boiling away, the cryostat is usually constructed with an outer jacket containing (significantly cheaper) liquid nitrogen at 77 K. Alternatively, a thermal shield made of conductive material and maintained in 40 K – 60 K temperature range, cooled by conductive connections to the cryocooler cold head, is placed around ...