Search results
Results from the WOW.Com Content Network
The temperature of liquid nitrogen can readily be reduced to its freezing point −210 °C (−346 °F; 63 K) by placing it in a vacuum chamber pumped by a vacuum pump. [2] Liquid nitrogen's efficiency as a coolant is limited by the fact that it boils immediately on contact with a warmer object, enveloping the object in an insulating layer of ...
When performed on a larger scale, this technique is called freeze-drying, and the cold trap is referred to as the condenser. Cold traps are also used in cryopump systems to generate hard vacua by condensing the major constituents of the atmosphere (nitrogen, oxygen, carbon dioxide and water) into their liquid or solid forms.
Two procedures for degassing are common. The first is known as freeze-pump-thaw — the solvent is frozen under liquid nitrogen, and a vacuum is applied. Thereafter, the stopcock is closed and the solvent is thawed in warm water, allowing trapped bubbles of gas to escape. [4] The second procedure is to simply subject the solvent to a vacuum.
In astronomy or planetary science, the frost line, also known as the snow line or ice line, is the minimum distance from the central protostar of a solar nebula where the temperature is low enough for volatile compounds such as water, ammonia, methane, carbon dioxide and carbon monoxide to condense into solid grains, which will allow their accretion into planetesimals.
As water freezes, tiny amounts of liquid water are theoretically still present, even as temperatures go below −48 °C (−54 °F) and almost all the water has turned solid, either into crystalline ice or amorphous water. However, this remaining liquid water crystallizes too fast for its properties to be detected or measured. [11]
Degassing, also known as degasification, is the removal of dissolved gases from liquids, especially water or aqueous solutions. There are numerous methods for removing gases from liquids. Gases are removed for various reasons.
Cryogenic IQF freezers immerse the product in liquid nitrogen at very low temperatures, freezing it rapidly while continuously moving the product to avoid block or lump formation. [5] Although this method shows good freezing results, it might lead to higher processing costs per weight of product due to the cost of the liquid nitrogen required.
Snap-freeze is a term often used in scientific papers to describe a process by which a sample is very quickly lowered to temperatures below -70 °C. This is often accomplished by submerging a sample in liquid nitrogen .