SAM Physics Assignment - Cryogenics

8/7/2019 SAM Physics Assignment - Cryogenics

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Physics Info Search

Prepared by Tan Chang Wei, S5


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What is Low

Temperature Physics??Cryogenics

Greek Kryos means freezing.

- Genes means being generated.Production of low temperature.

Study of phenomena under that temperature.

Started since 19th century by Michael Faraday.


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Production of Low

TemperatureHeat Conduction- Heat from higher temperature body flows to a lower

temperature body.

- Immersed the samples in cryogenics liquid or place incryogenic atmosphere.


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Production of Low

TemperatureEvaporate Cooling- Similar to the mechanism in which our body loses heat.

- Liquid is evaporated and heat from the liquid is used to

convert the particle to gaseous state.- As the process is continued, heat is slowly removed,

temperature drops.

Water

Evaporates

Temp

erat

e


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Production of Low

TemperatureJoule Thompson Effect- Cooling by rapid expansion

- Can also be done by reducing pressure

Temperatur

e

Gas

Airmolecule

s

Valve

P T

Pressure Law


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Production of Low

TemperatureAdiabatic demagnetization- Uses paramagnetic salt-large collection of particle that acts

like tiny magnets

- Used in Adiabatic Demagnetization Refrigerator (ADR)

N S

Temperatur

e

Salts

Liquid givesenergy tothe salts.

Spread out in a liquid, magnetic poles cause the salts to bemagnetic and line up in a same direction.Magnet is removedSalts return to originalpositionLiquid gives energy to the saltTemperature drops


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Application of

CryogenicsDeep Cryogenics Tempering- Improves performances, durability and strength of high alloy

and more.

Superconductivity- Has electrical resistance that is exactly zero, occurs in

certain materials.

- Current still can flow through even there is no Power Supply.


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Application of

CryogenicsRocket Propellants- Fuels and oxidants carried by rockets for propulsion

- Used by NASA

Medical Application- Apply Deep Cryogenics Tempering

- Increase wear resistance of expensive surgical tools


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Application of

CryogenicsAdiabatic Demagnetization Refrigerator (ADR)- Work using properties of heat and the magnetic properties

of certain materials.

- Uses salt pills that is thermally connected to the object to becooled.


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Application of

CryogenicsIndustrial Application- Apply Deep Cryogenics Tempering.

- Increase the wear resistance and strength of the metal.

- Examples: Razors, Clippers, Knives.

Automotive Applications

- Apply Deep Cryogenics Tempering .

- Increase the wear resistance of car engine parts.

- Examples: Piston, The Crank, Push Rods


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Problems of CryogenicsLow spread of low temperature application.

Inconvenient cryoliquids.

SOLUTIONS

Cryogen free alternative to low temperatureapplicationsPulse TubeOn-chip Refrigerator


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SAM Physics Assignment - Cryogenics

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