private formula
Formula has warnings so can not be used - press "edit" below in order to fix.
| Z | (dimensionless) |
| R | (dimensionless) |
| A | (dimensionless) |
| b1 | (dimensionless) |
| c1 | (dimensionless) |
| t | (dimensionless) |
| b | (dimensionless) |
| c4 | (dimensionless) |
| c3 | (dimensionless) |
| c2 | (dimensionless) |