Cryogenics being an important topic in physics shows that it is a cold topic.

1. Welcome to the world of
CRYOGENICS
The coolest thing ever!

2. CRYOGENICS
 The word cryogenics stems from Greek word “cryos” and means the “production
of freezing cold” the term is used as the synonym for the low temperature state.
 Cryogenics is the study of the production of extremely cold temperature. This field
of science also looks at what happens to a wide variety of materials from metals
to gases when they are exposed to these temperatures.
 The extremely low temperature are produced by using substances called cryogens,
such as Liquid Nitrogen (-196˚C) and Liquid Helium (-268˚C).

3. LIQUID NITROGEN
 Nitrogen gas makes up the major portion of the atmosphere
(78%) by volume.
 Inert, colorless, odourless, non-corrosive, non-flammable
liquid.
 Extremely cold.
 Volume of expansion of liquid to gas at 15˚C and 1 atm, i.e
1 litre of liquid nitrogen evaporated to form 682 litres of
nitrogen gas.

4. Methods of Liquefication
L i n d ’s M e t h o d Claude's Method

5. Lind’s Method
Air compressed to about 200 atm is passed through a water cooled
pipe where heat of compression is removed. It is then allowed to pass
through a spiral pipe having a jet at the end. Here expansion takes place
from 200 atm to 1 atm, which causes cooling.
Based upon
Joule Thomson Effect

6. Claude's Method
This process is based upon the principle that
when a gas expands adiabatically against an
external pressure (as a piston in an engine), it
does some external work. Since work is done by
the molecules at the cost of their kinetic energy,
the temperature of the gas falls causing cooling.
Claude’s process of liquefication of gases is
considered as the more efficient method of
liquefication as the gases like helium and
Hydrogen can’t be liquefy by Lind’s methods but
Can be done by this process.

7. DEWAR FLASK
Dewar flask is used generally in research
laboratories to hold liquefies gases for flash
freezing samples.
Consistent and efficient drying of dewar flasks is
Important to ensure desirable conditions before
using liquefied gases or other liquids.

8. Applications
 Cryogens are used vastly in the field of medical such as in the process of Magnetic
Resonance imaging (MRI).
 Liquid Helium cools down the superconducting magnets, which is the part of MRI
Scanners that generates a high-resolution images of the human body.
Magnetic Resonance Imaging(MRI)

9. Applications
 It is difficult to transmit power by overhead cables that why underground cables
are used, but they get heated and resistance of the wire increase leading to waste
of power.
 Superconductors are used to increase power throughout, requiring cryogenic liquids
to cool special alloy-containing cables to increase power transmission.
Power Transmission

10. Applications
When a large quantity of food must be transported to regions like war zones,
earthquake hit regions etc., it must be stored for a long time, so cryogenic
food freezing is used.
Frozen food
Cryogenic freezing is used to freeze food at an extremely fast rate. The food
is moved through a spray of liquid nitrogen or directly immersed In liquid
nitrogen. The liquid nitrogen boils around the food at a temperature
of −196 °C (−321 °F) and extracts a large amount of heat.

11. Applications
Forward-looking infrared (FLIR) cameras, typically used on military and civilian
aircraft, use a thermographic camera that senses infrared radiation.
Many infrared cameras require their detectors to be cryogenically cooled.
Forward looking infrared (FLIR)

12. Applications
Ultra-rapid freezing of blood in the form of droplets is a useful means of preserving
Red cells for blood-group studies. Storage and prolonged preservation of biological
Specimens have been more successful at cryogenic temperatures than at higher
storage temperatures.
Blood Banking

13. Applications
A cryogenic technology is the process of involvement or including
of usage of rocket propellants at a cryogenic temperature. It can
be the combination of liquid fuels such as: Liquid Oxygen (LOX), and
liquid hydrogen (LH2) as an oxidizer and fuel in the different mixtures
or proportions.
Rocket Engine

14. Applications
Cryogenic processing is a special type of heat-treating process that involves
cooling heat-treated steels and other metals to temperatures lower than -300°F.
The deep chilling of heat-treated parts allows the metal molecules to be
brought to “cryogenic stillness” to improve wear characteristics.
Metal Durability

15. Cryotherapy is the use of extreme cold to
freeze and remove abnormal tissue. Doctors
use it to treat many skin conditions
(including warts and skin tags) and
some cancers, including prostate, cervical
and liver cancer. This treatment is also called
Cryoablation.
Cryotherapy

16. Cryonics
Cryonics is the practice of preserving
Humans and animals at cryogenic
temperatures in the hope that future
science can restore them to a healthy
living condition as well as rejuvenate
them. At present cryonics can only be
performed after Pronouncement of legal
death of the cryonics subject.

17. Cryo-Microscopy
Transmission Electron cryo-microscopy (Cryo-TEM),
commonly known as cryo-EM, more specifically a type of
transmission electron microscopy (TEM) where the sample
is studied at cryogenic temperatures. Cryo‐electron
microscopy (cryo‐EM) is a structural Biological method that
is used to determine the 3D structures of Biomacromolecules.
After years of development, cryo‐EM has made great
achievements which has led to a revolution in structural biology.

18. Sorption is a physical process by which one substance becomes attached to
other. In sorption both adsorption and absorption takes place at the same
time.

19. An example of sorption is the charcoal used in gas masks to remove
poisons or impurities from a stream of air.

20. Sorption includes the processes of adsorption and absorption.
Adsorption:
Adsorption refers to the collecting of molecules by the
external surface or internal surface of solids or by the surface of liquids.
Involves only the surface area of material.
 Polymer Adsorption
(polyelectrolyte adsorption).
 Cryo-adsorption
(H adsorbed on porous material. Activated C).

21. Adsorbate:
The substance that gets adsorbed on to the surface.
Adsorbent:
The substance on the surface of which adsorption takes
place.

22. Following are the Techniques for Adsorption rate Measurement
Adsorption
Gravimetric
Technique
Volumetric
Technique
Pulse Flow
Technique

23. Gravimetric Technique
The gravimetric sorption technique is one of the most popular methods used to
determine the amount and rate of the interaction of a gas or vapor with a material.
The material can be a solid or liquid, and both thermodynamics and kinetics of the
sorption process are recorded.
A typical gravimetric sorption measurement has four stages:
• The sample is loaded into the analyzer
• In-situ degassing and activation are performed, if required
• Gas pressure is applied at programmed values
• Sorption uptake is determined from the measured weight changes

24. The gravimetric sorption technique works
by placing a sample onto a microbalance.
The weight of the sample is measured
continuously as a function of the applied
temperature and pressure. In a typical
measurement the temperature is constant
and the gas pressure is controlled.

25. Volumetric Technique
The adsorption cell was charged by the adsorbent sample, then to remove
any moisture or impurities, the sample was activated by passing the helium
gas in the adsorption tank (with a flowrate of 20 ml/min) at 573 K, under
vacuum, by a heating rate of 1 K/min and let thereafter at a constant during
a period of at least 12 h. The Temp and P are measured by sensors.

26. Pulse Flow Technique
The pulse adsorption apparatus uses the chemisorption of H2 or CO on rare metals
such as Pt and Pd to evaluate the active surface area. As the detector, TCD (Thermal
Conductivity Detector) is commonly used, which is a kind of gas chromatography.
Before the adsorption measurement, the sample needs to have the pretreatment
to clean the surface by oxidation and reduction. Then it flows the carrier gas such
as He and doses the adsorptive gas as pulses. It also uses the TCD detector to
detect the change in the gas concentration after going through the sample. The
dynamic method can measure the adsorption amount quickly compared to other
methods and is useful for the quality control.

28. Absorption:
Absorption refers to the process in which a substance penetrates
into the actual interior of crystals or blocks of amorphous solids or
liquids. Involves the whole area of material.
Water soaked by sponge/tissue.
Water vapors on silica gel.

29. Adsorption & Absorption

30. Types of Adsorption
Physical Adsorption Chemical Adsorption
Types of Absorption
Physical Absorption Chemical Absorption

31. Adsorption Absorption
It is a surface phenomenon It is a bulk phenomenon
It is rapid in the beginning and slows
down near the equilibrium
It occurs at a uniform rate
Depends on temperature Does not depend on temperature
It is exothermic It is endothermic
NH3 adsorbed by charcoal NH3 absorbed by water
DifferencesbetweenAdsorption&Absorption

32. Adsorption is generally classified into
physisorption (weak Vander wall
forces) and chemisorption (covalent
bond). It can also be caused by
electrostatic attraction.
During this process the molecules are
entirely dissolved or diffused in the
absorbent to form a solution.
The molecules are held on the
surface of the adsorbent and can be
removed.
Once the molecules are absorbed, it
becomes difficult to separate it from
absorbent.

33. Thank you
For your
attention