Exposure to high concentration of gaseous ammonia can cause lung damage. To prevent gaseous ammonia from leaking out, ammonia is transported in its liquid state through a pipe (k 5 25 W/m?K, Di, pipe 5 2.5 cm, Do, pipe 5 4 cm, and L 5 10 m). Since liquid ammonia has a normal boiling point of 233.38C, the pipe needs to be properly insulated to prevent the surrounding heat from causing the ammonia to boil. The pipe is situated in a laboratory, where air at 208C is blowing across it with a velocity of 7 m/s. The convection heat transfer coefficient of the liquid ammonia is 100 W/m2?K. Calculate the minimum insulation thickness for the pipe using a material with k 5 0.75 W/m?K to keep the liquid ammonia flowing at an average temperature of 2358C, while maintaining the insulated pipe outer surface temperature at 108C

d.) the average kinetic energy of the gas particles is greater in container b because its particles move faster.

a mercury barometer is a device that uses the physical properties of mercury in a tube to measure barometric pressure. mercury barometers are used for : -

1. measurement of atmospheric pressure  

2. determining the altitude of a place

3. weather forecasting

4. calibration and checking of aneroid barometers

5. application in fluid mechanics

6. measurement of pressure in aircrafts

7. surface weather analysis

8. preparation of barographs

9. usage in physical sciences like physics, astronomy & chemistry

10. preparation of aircraft altimeters

characteristics of mercury barometer : -

1.used to define and measure atmospheric pressure.

2.on the average at sea level the column of mercury rises to a height of about 760 mm.

3.this quantity is equal to 1 atmosphere.

4.it is also known as standard atmospheric pressure.

5.a barometer in which the weight of a column of mercury in a glass tube with a sealed top is balanced against that of the atmosphere pressing on an exposed cistern of mercury at the base of the mercury column, the height of the column varying with atmospheric pressure.

they are made of gases.

they have a spherical shape.

they make energy through fusion.