نتایج جستجو برای: fickian diffusion
تعداد نتایج: 163547 فیلتر نتایج به سال:
Abstract We present a numerical simulation study of advective–diffusive scalar transport in three-dimensional high-contrast discontinuous permeability fields, generated with truncated pluri-Gaussian geostatistical approach. The experiments are run an Eulerian approach using novel unified framework based on the finite-volume library OpenFOAM ® (Weller et al. Comput Phys 12(6):620–631, 1998), for...
The aim of this investigation was to develop and optimize bisoprolol fumarate matrix tablets for sustained release application by response surface methodology based on 2(3) factorial design. The effects of the amounts of calcium alginate, HPMC K4M, and Carbopol 943 in bisoprolol fumarate matrix tablets on the properties of bisoprolol fumarate sustained release matrix tablets like drug release a...
The low bioavailability (15%) and good solubility of Domperidone Maleate in acidic pH following oral administration favours development of a gastro retentive formulation. Gastroretentive floating matrix tablets of Domperidone Maleate were successfully prepared with hydrophilic polymers like HPMC K4M, HPMC K15M and HPMC K100M. From the Preformulation studies for drug excipients compatibility it ...
A novel methanol derived graphene (MDG) and gentamicin sulfate nanohybrid was prepared, and the loading and release behaviour of gentamicin on MDG is investigated. An efficient drug loading of 2.57 mg mg(-1) was obtained at pH 7. By applying release kinetic models, the mechanism of release of the drug from the MDG matrix was found to be following the Korsmeyer-Peppas model. However, the diffusi...
Modeling pollutant transport in heterogeneous media is an important task of hydrology. Pollutant a non-homogeneous environment typically exhibits non-local dynamics, whose efficient characterization requires parsimonious model with the feature. This study encapsulates characteristic pollutants into peridynamic differential operator (PDDO) and develops PDDO-based for quantifying observed behavio...
Numerical evidence of nondiffusive transport in three-dimensional, resistive pressure-gradient-driven plasma turbulence is presented. It is shown that the probability density function (pdf) of tracer particles' radial displacements is strongly non-Gaussian and exhibits algebraic decaying tails. To model these results we propose a macroscopic transport model for the pdf based on the use of fract...
Many practically relevant polymers undergoing desorption change from the rubbery (saturated) to the glassy (nearly dry) state. The dynamics of such systems cannot be described by the simple Fickian diffusion equation due to viscoelastic effects. The mathematical model solved numerically is a set of two coupled PDEs for concentration and stress. Asymptotic solutions are presented for a moving bo...
The present study was undertaken to develop a suitable transdermal matrix patch of Metoprolol tartrate with different proportions of polyvinyl pyrrolidone (PVP) and chitosan crosslinked with glutaraldehyde (GA). The prepared transdermal patches were subjected to different physicochemical evaluations such as thickness, tensile strength, folding endurance, drug content, swellability, surface pH, ...
A mathematical method called subordination broadens the applicability of the classical advection--dispersion equation for contaminant transport. In this method, the time variable is randomized to represent the operational time experienced by different particles. In a highly heterogeneous aquifer, the operational time captures the fractal properties of the medium. This leads to a simple, parsimo...
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