Figure 3: Evolution of the fitting parameters as a function of time.
From: Formation of calcium sulfate through the aggregation of sub-3 nanometre primary species
(a) Elongated scatterers with lengths, L, and cross-sectional radii, R, up to ∼1,500 s; (b) pre-factors φVpart(Δρ)2 and φ(Δρ)2 up to ∼1,500 s; the average of the φ(Δρ)2 product is marked with a horizontal solid line; (c) mean effective hard-sphere radii <ReHS> and their s.d.’s, σ characterizing <SHS(q)>; (d) local volume fractions, v, characterizing <SHS(q)>; (e) surface area contribution, A′, and surface fractal dimension, Ds, characterizing <SSF(q)>. Note that up to 600 s the A′ and Ds values exhibited very large uncertainty, due to the limited contribution of large scatterers in the low-q range of the scattering patterns. For Ds (<600 s) any value between 2 and<3 would produce reasonable fits, but the yielded A′ values for all Ds>2 were significantly out of trend and are thus not shown; (f) pre-factor φVpart(Δρ)2 evolution up to 5,400 s; (g) Degree of crystallization α versus time from the corresponding WAXS measurements derived from the change in the area of the (020) WAXS reflection of gypsum measured simultaneously with the corresponding SAXS patterns. The background colours in a–f indicate stages I–IV, according to the legend. Time scales are in seconds (horizontal axes) except for g where they are in thousands of seconds.
