A water-resistant sheet used for water-proofing applications is formed from an impermeable polymeric material. The microstructure of the sheet is engineered to provide open pores of diameter D = 10 µm that extend through the entire thickness of the L = 100-µm-thick sheet. The pore diameter is large enough to allow water vapor to be transferred through the pore, but is sufficiently small to prohibit liquid water from penetrating through the sheet. a) Determine the rate (mol/s) at which water vapor is transmitted through a single pore when saturated liquid exists on the top of the sheet and moist air at a relative humidity of 50% exists on the bottom side of the sheet at temperature of T = 298 K and a pressure of P = 1 atm. At 298 K, the diffusion coefficient for water vapor through air is, .DAB = 0.26 x 10-4 m2/s.

b) Determine the rate (mol/s) at which water vapor is transmitted through a single pore in the absence of advection. Comment on the results.

c) Investigate the sensitivity of the transfer rate, both including and neglecting advection, to temperature. Consider a temperature range from 300 K to 360 K. Comment on the results.

Explanation is in the file

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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.