نتایج جستجو برای: non fickian diffusion mechanism

تعداد نتایج: 1961425  

2015
D. A. Edwards

Many electrochemical devices are formulated on conjugated polymer films. A model is presented for electrogenerated chemiluminescence in such systems. The resulting diffusion equation for ion transport has a standard Fickian form, but with a highly nonlinear diffusion coefficient. The asymptotic analysis of the equation involves both intermediate layers and logarithmic matching. The asymptotic r...

Journal: :Acta poloniae pharmaceutica 2016
Hina Raza Nazar Muhammad Ranjha Rabia Razzaq Mehvish Ansari Asif Mahmood Zermina Rashid

Chondroitin sulfate and sodium alginate were incorporated in different ratios to prepare glutaraldehyde (GA) crosslinked microspheres by water-in-oil emulsion crosslinking method for delivery of 5-flurouracil (5-FU) to colon. Chemical interaction, surface morphology, thermal degradability, crystallinity evaluation, elemental analysis and drug release results were computed by using FTIR, SEM, DS...

Journal: :journal of reports in pharmaceutical sciences 0
rahim bahri-najafi gholam reza asghari hamid reza dehlavi

buccal mucoadhesive films have attracted great attention among mucoadhesive systems due to their ability to adhere and remain on the oral mucosa and to release their drug content gradually. the aim of the current study was to formulate the ziziphus jujuba aqueous extract as buccal bioadhesive film, which continiously releases the drug at sufficient concentration for reducing the frequency of th...

Dr. Ahmed, M. Saeed

Due to the fact that many application processes take place at different temperature, better examining and understanding of swelling properties as a function of temperature is essential for such application. The temperature effect on the swelling properties of commercial polyacrylic acid (PAA) hydrogel beads was investigated as a function of time and temperature. Gel bead size, swelling equilibr...

Dr. Ahmed, M. Saeed

Due to the fact that many application processes take place at different temperature, better examining and understanding of swelling properties as a function of temperature is essential for such application. The temperature effect on the swelling properties of commercial polyacrylic acid (PAA) hydrogel beads was investigated as a function of time and temperature. Gel bead size, swelling equilibr...

Journal: :Nanoscale 2011
Himanshu Pandey Vyom Parashar Rashmi Parashar Rajiv Prakash Promod W Ramteke Avinash C Pandey

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...

2010
SIMON SHAW Mark Ainsworth

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...

2002
A. D. Drozdov

Experimental data are reported on moisture diffusion and the elastoplastic response in uniaxial tensile tests of an intercalated nanocomposite with vinyl ester resin matrix and montmorillonite clay filler at room temperature. Observations in diffusion tests show that the moisture transport in the neat resin is Fickian, whereas it becomes noticeably anomalous (non-Fickian) with the growth of the...

2004
Ludovic Berthier David Chandler Juan P. Garrahan

– The interplay between self-diffusion and excitation lines in space-time was recently studied in kinetically constrained models to explain the breakdown of the Stokes-Einstein law in supercooled liquids. Here, we further examine this interplay and its manifestation in incoherent scattering functions. In particular, we establish a dynamic length scale below which Fickian diffusion breaks down, ...

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