“…As X changes from 0 to ∞, the following changes occur: the expression fh(R, T, φ, φ0) (9) transforms from the formula fg(R, T, φ, φ0) (5) to the formula fg 0 (R, T, φ, φ0) (6), and the expression gh(R, T, φ, φ0) (17) transforms from the formula gf (R, T, φ, φ0) (14) to the formula gf 0 (R, T, φ, φ0) (15). This means that the greater the transparency of the object is, the more the formulas for the GDC approximation (5), ( 14) are transformed into formulas for the PODC approximation (6), (15).…”