D	is the diffusion coefficient.
r, z	are radial and axial cylindrical coordinates.
t	is time.
R	is the radius of a cylindrical specimen.
l	is the specimen length.
U (r, z, t)	is the moisture concentration at a sample point with cylindrical coordinates r, z at time t.
Q 0	is the initial moisture content in the specimen.
Q ∞	is the equilibrium moisture content in the specimen.
φ (r, z)	is the initial moisture concentration in the specimen.
U 0	is the border moisture concentration.
∆	is the Laplace operator.
∆r, z	is the Laplace operator in a cylindrical coordinate system without an angular component.
α, λ, μ	are the eigenvalues of operators.
J 0	is a zero-order Bessel function.
γk	is the k-root of the zero Bessel function.
A, B, and C	are constants.
$\overline{U}\left(t\right)$	is the average moisture concentration in a specimen at time t.
Q (t)	is the mass of moisture in a specimen at time t.
F 0	is the Fourier criterion.
Wt	is the relative moisture content in the specimen at time t.
Pt	is the sample weight at time t.
P 0	is the initial sample weight.
σ*	is the material strength.
E	is the elastic modulus.