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''.
In the transition region where the friction factor depends on both Reynolds number and the relative roughness (Îµ/D), the friction factor of the commercial pipe is found to be different from those obtained from the sand roughness used by Nikuradse (see Figure 2).