Fig. 4. Schematic of the processes and geometry involved in models of particle transport. Comparison between typical experimental geometry and the corresponding dimensionally-reduced mathematical geometry. Influence of different mechanisms on particle properties and location. Diffusion results in the random motion of the particles. Sedimentation results in the motion of the particles in the direction of gravitational acceleration. Aggregation results in the clustering of multiple particles, increasing the diameter and altering the density of the particles. Dissolution decreases the diameter of the particles and also produces individual ions. Protein binding results in the formation of a protein corona on the particle surface, increasing the diameter and altering the density of the particles.