We study theoretically and numerically the steady state diffusion controlled reaction A + B → ∅, where currents J of A and B particles are applied at opposite boundaries. For a reaction rate λ, and equal diffusion constants D, we find that when λJ −1/2 D −1/2 ≪ 1 the reaction front is well described by mean field theory. However, for λJ −1/2 D −1/2 ≫ 1, the front acquires a Gaussian profile-a r...

The configuration-controlled regime and the diffusion-controlled regime of conformation-modulated fluorescence emission are systematically studied for Markovian and non-Markovian dynamics of the reaction coordinate. A path integral simulation is used to model fluorescence quenching processes on a semiflexible chain. First-order inhomogeneous cumulant expansion in the configuration-controlled re...

Effective molarities for diffusion-controlled r actions between spherical reactants with reactive patches are calculated analytically and by Brownian dynamics simulations. Unimolecular reaction systems with internal translational motion in one, two, and three dimensions are investigated and compared with bimolecular reactions in three dimensions. Rotational diffusion is included in all cases in...

in this paper, a modeling tool for risk assessment analysis of the movement of hydrocarbon contaminants in the vadose zone and mass flux of contamination release into the groundwater table was developed. also, advection-diffusion-reaction equations in combination with a three-phase equilibrium state between trapped air, soil humidity, and solid particles of unsaturated soil matrix were numerica...

In this paper, carbon nanotubes (CNTs) were added into chitosan (CS) hydrogels in the form of chitosan modified CNTs (CS-CNTs) composites to prepare carbon nanotubes hydrogels (CNTs-GEL). The products, named CS-MWCNTs, were characterized by scanning electron microscope (SEM) and Fourier transform infrared (FTIR) spectroscopy. Swelling properties and effect of pH on controlled release performanc...