Video-based fractional order identification of diffusion dynamics for the analysis of migration rates of polar and nonpolar liquids: Water and oil studies

Diffusion dynamics of water and oil are observed in real-time using video images. Savitzky–Golay derivative filtering ensures accurate localization of the liquid front. System identification demonstrates that a fractional-order model with only two parameters may be used to describe the dynamics of the diffusion process. The method paves the way for video-based cellulose filter paper microfluidics and lateral flow assays, which are low cost and have broad diagnostic applications.