• Units for particulate powder measurement

a) One angstrom unit (A.O. or Å)= 0.1 nanometers, or one ten-thousandth of a micron (10^-4 microns), or one hundred-millionth of a centimeter (1 x 10^-8 cm.).

b) One angstrom is the diameter of a hydrogen atom -- the smallest element.

• Particulate Measurement Definitions:

a) Apparent Density (g/cm³)= weight in grams x 0

b) Flow Rate= Time in seconds per 50 grams

c) Mesh= Number of openings per lineal inch, starting with a ruler zeroed on the center of any wire

d) Micron= One micron (µ) equals 10^-4 centimeters or 0.001 millimeters

e) Nano= A prefix meaning one billionth or 10^-9. The symbol is n

f) Nanometer= One nanometer (nm) equals ten angstroms or 1 millimicron

g) Sieve Analysis refers to the particle size distribution, usually expressed as weight percentage retained upon each of a series of standard sieves of decreasing size and the percentage passed by the sieve of finest size

h) Surface Area= A measure of the surface area per unit weight

i) Wavelength= One wavelength (at 5500 Å) equals 21.8 x 10^-6 inches