The Cold Science of Cryogenics
The word Cryogenics is originated from greek words ‘kryos’ meaning ‘frost’ and ‘genics’ meaning ‘to produce’. Cold science suggests that branch of science carrying out processes at low temperatures. But how much low? Here the temperature range is 100 Kelvin (K) to absolute zero (0 K). Cryogenics is the branch of physics which deals with the study of how to get to extremely low temperatures & of how the materials behave when they get there. Such low temperatures studied in cryogenics do not occur in nature. For this several cryogenic techniques are used to reach to those temperature ranges.
Besides the familiar temperature scale of Fahrenheit & Celsius, Cryogenicists use Kelvin & Rankine scale. Cryogenic techniques are used to liquefy gases present in our atmosphere because atmosphere is the only source. Gases like Nitrogen, Oxygen, hydrogen and rare gases like Neon, Helium are liquefied. Now why these gases are liquefied?
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The answer is, liquid occupies less volume than gas. These liquefied gases are called Cryogenic Liquids. Some cryogenics liquids are used as coolants, some are used as oxidizers and some are used as cryogenic fuels. When materials or substances come in contact with these cryogenic liquids, the materials undergo tremendous change in their properties & crystal structure. For example, when a piece of flexible rubber is put in liquid nitrogen for few seconds, becomes so hard and brittle that when it is dropped from some height to the floor, it may break into pieces.
The apparatus to liquefy oxygen was prepared by two cryogenicists independently. One was physicist Louis Paul Cailletet from Paris and other was prof. Raoul Pictet from Geneva in 1877. Cryogenics has played a vital role in the development of technology. It has vast applications.
One of the major application is Cryogenic Engine in which Liquid Oxygen(LOX) is used as oxidizer which oxidizes the fuel(Liquid Hydrogen; LH<sub>2</sub>) to produce the required thrust. These engines are used during Satellite launch programs. It was very difficult to use gaseous forms of O<sub>2 </sub>& H<sub>2 </sub>also gases require more volume. So by using Liquid Nitrogen(LN<sub>2</sub>) as cryogenic coolant, these gases were liquefied & filled in cylinders under pressure. It is also a matter of pride that INDIA is the sixth country in the world to have its indigenous cryogenic engine. It was used in the launch program of communication satellite GSAT-4 in april 2010 by <a title="ISRO GSLV F06 Fails For The Second Time" href="https://www.crazyengineers.com/isro-gslv-f06-fails-for-the-second-time/">GSLV-D3</a>.
Another application is Maglev Trains which are also called as Bullet Trains. They have the travelling very fast. The rails are made of semiconductor material. When the semiconductors come in contact with LN<sub>2 </sub>they become superconductors and repel the magnetic base of train which makes the train to levitate.
Cryogenic treatment improves the rigidity of automotive parts thus increasing the life of automobile. Besides these cryogenics is also applied in medical fields also. Cryosurgery, preservation of seeds, embryos is done at very low temperature at about -130<sup>o</sup>C.
Researches and developments are still going on in cryogenic treatments.
Besides the familiar temperature scale of Fahrenheit & Celsius, Cryogenicists use Kelvin & Rankine scale. Cryogenic techniques are used to liquefy gases present in our atmosphere because atmosphere is the only source. Gases like Nitrogen, Oxygen, hydrogen and rare gases like Neon, Helium are liquefied. Now why these gases are liquefied?
The answer is, liquid occupies less volume than gas. These liquefied gases are called Cryogenic Liquids. Some cryogenics liquids are used as coolants, some are used as oxidizers and some are used as cryogenic fuels. When materials or substances come in contact with these cryogenic liquids, the materials undergo tremendous change in their properties & crystal structure. For example, when a piece of flexible rubber is put in liquid nitrogen for few seconds, becomes so hard and brittle that when it is dropped from some height to the floor, it may break into pieces.The apparatus to liquefy oxygen was prepared by two cryogenicists independently. One was physicist Louis Paul Cailletet from Paris and other was prof. Raoul Pictet from Geneva in 1877. Cryogenics has played a vital role in the development of technology. It has vast applications.
One of the major application is Cryogenic Engine in which Liquid Oxygen(LOX) is used as oxidizer which oxidizes the fuel(Liquid Hydrogen; LH<sub>2</sub>) to produce the required thrust. These engines are used during Satellite launch programs. It was very difficult to use gaseous forms of O<sub>2 </sub>& H<sub>2 </sub>also gases require more volume. So by using Liquid Nitrogen(LN<sub>2</sub>) as cryogenic coolant, these gases were liquefied & filled in cylinders under pressure. It is also a matter of pride that INDIA is the sixth country in the world to have its indigenous cryogenic engine. It was used in the launch program of communication satellite GSAT-4 in april 2010 by <a title="ISRO GSLV F06 Fails For The Second Time" href="https://www.crazyengineers.com/isro-gslv-f06-fails-for-the-second-time/">GSLV-D3</a>.
Another application is Maglev Trains which are also called as Bullet Trains. They have the travelling very fast. The rails are made of semiconductor material. When the semiconductors come in contact with LN<sub>2 </sub>they become superconductors and repel the magnetic base of train which makes the train to levitate.
Cryogenic treatment improves the rigidity of automotive parts thus increasing the life of automobile. Besides these cryogenics is also applied in medical fields also. Cryosurgery, preservation of seeds, embryos is done at very low temperature at about -130<sup>o</sup>C.
Researches and developments are still going on in cryogenic treatments.
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