The sedimentation rate of red blood cells (RBC's) in blood diluted with water and anticoagulant is often measured as a test for inflammatory diseases in humans. If we treat a red blood cell as a cylindrical disk with a diameter of 8.0 microns and thickness of 2.0 microns, what would be its sedimentation rate (in mm/hr) in water? The density of a red blood cell is 1110 kg/m³ and take the density and viscosity of the diluted blood plasma surrounding the cell to be 1000 kg/m³ and 0.001 Pa's respectively. Assume that the drag force is the same as for a sphere of 8.0 micron diameter for conditions where Stoke's law applies (very low Reynolds number). 2.0 μm 8.0 μm RBC V settling

A reverse-osmosis unit is used to obtain pure water from saline water. The coefficient of water permeation is 0.1 mol/cm2 s atm. The pressure differential across the membrane is 0.2 atm, and the osmotic pressure differential is 0.05 atm. The water flux across the membrane is most nearly (A) 0.0050 mol/cm2·s (B) 0.015 mol/cm2·s (C) 0.050 mol/cm2·s (D) 0.15 mol/cm² ·s

Acetic acid (CH3COOH) diffuses across a 1-mm thick film of non-diffusing water. The concentration of acetic acid on opposite sides of water film are 9% by weight (density=1012 kg/m³) and 4% by weight (density=1003.2 kg/m³). Calculate the rate of diffusion of acetic acid at 17 °C. DATA: The diffusivity of acetic acid in water at 25 °C = 1.11 x 109 m²/s Viscosity of acetic acid solution at 25 °C = 1.1336 x 10-³ Pa. Viscosity of acetic acid solution at 17 °C = 1.2883 x 10-³ Pa.s

The diffusion constant for the amino acid glycine in water is 1.06 × 10-9 m2/s. In a 2.0-cm-long tube with a cross-sectional area of 1.3 × 10-4m2, the mass rate of diffusion is m/t = 4.2 × 10-14 kg/s, because the glycine concentration is maintained at a value of 9.1 × 10-3 kg/m3 at one end of the tube and at a lower value at the other end. What is the lower concentration?

A// Fick's first diffusion law states that: Mass flux = -D Where mass flux = the quantity of mass (g/cm²/s), D a diffusion coefficient (1.6×10-6 cm²/s), c concentration, and x = distance (cm). An environmental engineer measures the following concentration of a pollutant in the sediments underlying a lake as the following: 0 2 6 0.12×10-6 0.64x10-6 1.20×10-6 Use a suitable Newton's interpolation formula available to estimate the derivative at x = 0 and then calculate the mass flux of pollutant. X, cm C, g/cm³ de dx =

A quiescent body of water has a depth of 600 mm. The DO level at the bottom after 16 days is 3.5 mg/l when the surface is exposed to the atmosphere at a temperature of 25o Determine the DO of the water body. The saturated DO at 25oC is 8.5 mg/l and the diffusion coefficient (kd) at 25oC is 2.5 x 10-3 mm2/s.