One technique to study electrochemical oxidation phenomena in thin polymer films is the generation of electrogenerated chemiluminescence (ECL) waves. Such waves are sharp and easy to image, and recent experiments have shown both constant-speed and Fickian-style wave behavior. One way to model such waves mathematically is to track the concentration of the ion clusters in the polymer film. One su...

In this paper we propose a mathematical model to describe the evolution of glioma cells taking into account the viscoelastic properties of brain tissue. The mathematical model is established considering that the glioma cells are of two phenotypes: migratory and proliferative. The evolution of the migratory cells is described by a diffusion-reaction equation of non Fickian type deduced consideri...

Desorption of saturated polymers can be inhibited if a nearly dry (glassy) skin with a low diffusion coefficient forms at the exposed surface. In addition, trapping skinning can occur, where an increase in the force driving the desorption decreases the accumulated flux desorbed. The dynamics of such systems cannot be described by the simple Fickian diffusion equation. The mathematical model pre...

The use of ultrasound to enhance the transport phenomena in food processes has been well recognised in recent times. The objective of this study was to evaluate the effect of sonication on hydration rate and pasting profile of navy beans. The hydration kinetics for control and ultrasound assisted soaking was mathematically described using mechanistic (Fickian diffusion) and empirical (Peleg's e...

We describe methods for the measurement of translational diffusion in very large static magnetic field gradients by NMR. The techniques use a "hole-burning" sequence that, with the use of fringe field gradients of 42 T/m, can image diffusion along one dimension on a submicron scale. Two varieties of this method are demonstrated, including a particularly efficient mode called the "hole-comb," in...

Osmotically-assisted membrane processes (OAMP) are separation technologies that leverage osmotic gradients to recover water from brine. Accurate modeling of the solute-coupling effects for transmembrane transport is integral development and subsequent optimization OAMP unit operations. In literature, multicomponent in commonly linearized, species fluxes computed using binary solution-diffusion ...

A thermokinetic model of hydrogen diffusion across a metallic tube is established. It includes the enthalpy change of the metal– hydrogen reaction, heat losses, dependences of reaction rate and hydrogen diffusion coefficient on temperature, and self-stress effects, etc. A phenomenon, the super fast diffusion of hydrogen before the up-hill diffusion and Fickian diffusion during hydrogen gas char...