Agate is good protective energy stone, especially for children, and is very calming and soothing. It also can help strengthen the body's connection to the earth.
The friction factor, f, is a dimensionless factor that depends primarily on the velocity u, diameter D, density Ï, and viscosity Î·. It is also a function of wall roughness which depends on the size Îµ, spacing Îµ' and shape of the roughness elements characterized by Îµ''.
Marginal factor cost. In microeconomics, the marginal factor cost (MFC) is the increment to total costs paid for a factor of production resulting from a one-unit increase in the amount of the factor employed. It is expressed in currency units per incremental unit of a factor of production (input), such as labor, per unit of time.