Solid particles can have a variety of shapes . These forms define the way these particles are deposited on surfaces.
For example nodular particles in the form of a ball, elongated particles in the form of a needle (such as fibers of asbestos, mineral fibers, textile fibers) and laminar particles rather flat (such as talc or graphite).
Small particles often form large (cluster). For example exhaust gases and smoke produced from welding.
For example nodular particles in the form of a ball, elongated particles in the form of a needle (such as fibers of asbestos, mineral fibers, textile fibers) and laminar particles rather flat (such as talc or graphite).
Small particles often form large (cluster). For example exhaust gases and smoke produced from welding.
It is important to learn how particles dwell in the air and how they descent .
Physical Law
Particles fall downward by gravity . The speed with which they sink rises initially, then remains constant, however, (the maximum rate of descent). This is the case when the gravity is compensated by the friction force.
Sir George Gabriel Stokes described movement of particles. Movement depends on friction force. A spherical (ball-shaped) body will have speed, the viscosity -- a measure of the thickness of gas or a liquid -- or the substance in which the body is located
Stokes found that the terminal velocity of spherical particles with a diameter in the size range 1 - 50 microns is proportional to the density and the square of the ball diameter. In other words, that
Particles with a diameter half the size have half the descent rate..
