nptel mechanical engineering thermodynamics pdf

Thus, lines joining places of equal temperature are called Isotherms. They are also used to show the time variation of temperature with altitude in the atmosphere or depth in soil or water.In meteorology, they are commonly used to show the ratio of temperature at the Earth's surface or on a chart demonstrating steady level or steady pressure.It means that the temperature is nearly the same across the latitudes.Isotherm lines are nearly parallel to latitude lines.Isotherms are lines drawn on a weather map that connect points of equal temperature.The most commonly used gases for turning to liquid for cryogenics are oxygen, nitrogen, hydrogen, as well as helium.The environment is considered to be cryogenic once gas starts to liquefy. The liquid gases at -150 degrees Celsius or below -150° C can be used to freeze other materials.The actions of all molecules stop at this temperature by causing the molecules to be at the lowest possible state of energy.Temperature -273° C is the absolute lowest temperature that can be achieved. For instance, while water transforms from the liquid state to the solid at 32° F (0° C), then cryogenic temperatures range much lower that is from -150☌ to -273° C.

Rapidly moving molecules have a relatively higher temperature than molecules moving slowly.

The temperature of any material is the measure of the energy that the material is containing.

These studies have led to advancements not only in our understanding of different materials but also in the creation of totally new technologies and industries.

It is because they transit from gas to liquid to a solid-state.

Ultra-cold or cold temperatures will change the chemical properties of materials, which provides an interesting area of study for all the researchers who wish to examine the materials.

Cryogenics is the prediction of the behaviour of materials at low temperatures.

Nptel mechanical engineering thermodynamics pdf