The branch of science that deals with the production and use of low temperatures is called “Cryogenics”.
The word cryogenic has its origin from the Greek “Kryos”, which means ‘ice-cold’. Hence it is the study of materials at very low temperature i.e., temperature close to absolute zero (-273° C). At very low temperature, many materials show peculiar behaviors. Hence cryogenics has a lot of scientific advantages to its credits that pave the way for its vast field of applications. From laser fusion to development of cryogenic rocket fuel it is applied successfully in many other fields such as medicine and surgery, in biological researches and agriculture.
Uses of Cryogenics:
(i) Laser fusion:
Frozen pellets of isotopes of hydrogen, i.e., deuterium and tritium are raised by lasers to high temperatures for fusing where the, hydrogen atoms combine and relatively vast amount of energy is released. This is the major energy-producing process in the future and cryogenics has played a vital pan in the development of lasers fusion process.
(ii) Cryogenic rocket fuel:
Rockets usually use two kinds of fuels i.e. solid and liquid and for combustion of fuel, oxidiser is required. The oxidizer and the rocket fuel together are known as propel Ian t. Always liquid-fuel gives better efficiency and high performance as compared to its solid counterpart due to their possessing of large specific impulse. So liquid fuelled rockets work better. For much better performance, cryogenic rocket engines are being used where liquid oxygen (temperature = – 1S3°C) and liquid nitrogen (temperature = – 253° C) act as propellant.
In order to maintain the propellants in a cryogenic engine at extreme low temperature, proper provisions for insulation, use of low temperature with standing suitable materials and careful handling of liquid hydrogen and nitrogen as they are very explosive, should be made.
Countries like USA, Russia and Japan have succeeded in developing cryogenic rocket engine.
Japan has its LE-5 cryogenic engine for its satellite launching. The USA has developed its RL-10 engine and the famous Adriane Launcher of European Space Agency uses a HM-7 cryogenic engine. India entered into a deal with Russia for the transfer of cryogenic technology. Now, as that deal is already broken off, there is no other option left for India except developing indigenously its own cryogenic rocket engine. And that depends upon the success of the ISRO scientists.
(iii) Medicine and surgery:
The application of cryosurgery is very popular in the field of medicine and surgery, as it is now being used rampantly for the destruction of tumors, treatment of certain neurological disorders, the reattachment of retinas and the healing of small retinal holes in the eyes.
(iv) Biological researches and agriculture:
Most significant contribution of cryogenic to biology and agriculture is deep-freezing preservation. Preservation of tissues, organs (like eyes, kidneys), bloods for transplantation and transfusion and seeds and Other vegetative parts in plants in the germanplasm banks are the important ones. For the conservation of biodiversity, these germless banks play a crucial role.
The very low temperature is maintained using liquid nitrogen. Semen’s in bulls and buffaloes are preserved and transported for use in artificial inseminations through cryo-preservation. The food materials, dairy products, fishes, prawns and shrimps and other marine products can be preserved for a larger period in ice-cold temperature.
Again, cry biological researches on living organisms give better information’s to scientists regarding the exposure and endurance of organisms to extreme low temperatures. This helps in the studies of the possibility of extra terrestrial life.