Wadell [110], [111], [112] defined the shape of a particle as having sphericity, ψ, a valid quantity of particle shape evaluated by Eq. (1) [112]. (1) ψ = s S. Where s is the surface area of a sphere with a same volume as the particle, S is the actual surface area of the particle. Which as a working formula is Eq. (2) [110], [111]. (2) ϕ = d ...