The reduction of number of cells from 10¹⁰ to one will result into the del factor (Δ) of

For laminar flow of Newtonian fluid through a smooth round pipe, the ratio of average fluid velocity to the maximum velocity is

The heat conduction in dry air is

The efficiency of fibrous filter by combined mechanism is given by(where η_imp,η_int,η_dif are the efficiencies by impaction, interception and diffusion respectively)

The collection efficiency by impaction increases with