The first contribution, which is proportional to a constant I 0 , describes scattering from Porod interfaces manifesting themselves at 10 s and thereafter. The scattering originates from large objects, i.e. micron-sized particles >> d max , relative to the available q-range, where q min = 0.1 nm -1 and d max = 2π/q min . Here, the exponent D is associated with a fractal dimension, and takes values 3 < D ≤ 4, where D = 4 represents a smooth interface, while D < 4