Spatial Modeling of Formation of Gel
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Program
Engineering mathematics and computational science (MPENM), MSc
Publicerad
2022
Författare
Antonsson, Jakob
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Understanding and predicting colloidal interaction is important in a variety of
applications. In this study, we investigate aggregation dynamics of colloidal silica
by generating simulated structures and comparing them to experimental data
gathered through scanning transmission electroscopy (STEM). More specifically,
diffusion-limited cluster aggregation (DLCA) and reaction-limited cluster aggregation
(RLCA) models with different functions for the probability of particles sticking
upon contact were used. Aside from using a constant sticking probability, the sticking
probability was allowed to depend on the masses of the colliding clusters and
on the number of particles close to the collision. It was found that in comparison
to using a constant sticking probability, both the mass-dependent and neighbordependent
sticking probability improved the goodness-of-fit of spatial summary
statistics when the simulated data were compared to the experimental data. The
models were also compared based on fractal dimensions. Both in terms of goodnessof-
fit for the summary statistics and the fractal dimension, the structures generated
with a neighbor-dependent sticking probability were the most similar to the experimental
data. This model was further analyzed by conducting global envelope
tests based on the spatial summary statistics. The tests showed that although the
summary statistics are similar for the simulated and experimental structures, there
are also systematic deviations. Structures generated with the same model were also
compared with the STEM data by simulating flow and diffusion. From this analysis,
it was seen that the permeability and the geometry factor of the simulated and
experimental structures were relatively similar.