A hybrid particle/continuum algorithm is formulated for Fickian diffusion in the fluctuating hydrodynamic limit. The particles are taken as independent random walkers; the fluctuating diffusion equation is solved by finite differences with deterministic and white-noise fluxes. At the interface between the particle and continuum computations the coupling is by flux matching, giving exact mass co...

Hydrogels based on poly(acrylic acid) and gelatin crosslinked with N,N'-methylene bisacrylamide (0.5mol%) and glutaraldehyde (4%), respectively, forming an interpenetrating network were employed as matrices, for studying the loading and release of gentamicin sulphate. The release kinetics of gentamicin sulphate was evaluated in water (pH approximately 5.8), phosphate buffer (pH 7.4) and citrate...

We present a general derivation of the non-Fickian behavior for the self-diffusion of identically interacting particle systems with excluded mutual passage. We show that the conditional probability distribution of finding a particle at position x(t) after time t, when the particle was located at x(0) at t=0, follows a Gaussian distribution in the long-time limit, with variance 2W(t) approximate...

Abstract. The problem of non-local nonlinear non-Fickian polymer diffusion as modelled by a diffusion equation with a nonlinearly coupled boundary value problem for a viscoelastic ‘pseudostress’ is considered (see, for example, DA Edwards in Z. angew. Math. Phys., 52, 2001, pp. 254—288). We present two numerical schemes using the implicit Euler method and also the Crank-Nicolson method. Each sc...

This study aims to evaluate the validity of Fractional Advection-Dispersion equation (FADE) in breakthrough curves saturated homogenous soil media, i.e. clay, and examine three primary restraints, pore water velocity, dispersion coefficient, order fractional differentiation which are impacting solute transport behavior (Fickian or Non-Fickian). In this study, FADE framework used characterize pr...

Hybrid polymeric networks composed of polyacrylamide and chitosan were developed to determine their swelling and ascorbic acid delivery kinetics at various chitosan concentrations. The hybrid acrylamide/chitosan hydrogels were synthesized in aqueous itaconic acid solution (1% w/w). Young’s modulus was also evaluated for the hydrogels, and the results were correlated with the swelling properties...

Present study was undertaken to assess the potential of Glycerosomes as a novel drug delivery system for topical application of Minoxidil. Pre-formulation studies were done for identification of drug as well as for determination of its physiochemical properties. Spectra of various mixtures of drug and excipients do not show any additional peak thus, indicating compatibility with each other. Gly...

Using random walk simulations we explore diffusive transport through monodisperse sphere packings over a range of packing fractions, φ, in the vicinity of the jamming transition at φc. Various diffusion properties are computed over several orders of magnitude in both time and packing pressure. Two well-separated regimes of normal, “Fickian” diffusion, where the mean squared displacement is line...

We analyze a pair of diffusion equations which are derived in the infinite system-size limit from a microscopic, individual based, stochastic model. Deviations from the conventional Fickian picture are found which ultimately relate to the depletion of resources on which the particles rely. The macroscopic equations are studied both analytically and numerically, and are shown to yield anomalous ...