ABSTRACT We extend the method proposed by Miller and Rouet to formulate analytic solutions for th... more ABSTRACT We extend the method proposed by Miller and Rouet to formulate analytic solutions for the electric potential and field in a one-dimensional plasma satisfying periodic boundary conditions. We have also devised an event-driven algorithm to follow the time evolution of the system and to study its dynamical properties. In a dynamical system, the presence of positive Lyapunov exponents indicates that the system is chaotic. Of particular interest is the value of the largest (maximal) Lyapunov exponent which is usually sufficient to point toward the degree of chaos in the system. Using our new approach for defining the phase-space distance in systems with periodic boundary, we have employed our algorithm to find the largest Lyapunov exponent in the periodic plasma. Results obtained from our algorithm will be discussed with a view to exploring the dependence of chaotic properties of the system on its initial state.
Abstract: Osteoarthritis knee is one of the most prevalent disorders in the Indian subcontinent. ... more Abstract: Osteoarthritis knee is one of the most prevalent disorders in the Indian subcontinent. The wide prevalence and varying features makes it a disease of disguise. Multiple etiological factors have been described. The most recent is genetic contribution in ...
It has shown that passive fluid particles moving on periodic orbits can be used to `stir' a visco... more It has shown that passive fluid particles moving on periodic orbits can be used to `stir' a viscous fluid in a two-dimensional lid-driven cavity that exhibits a figure-eight flow pattern (Stremler & Chen 2007). Fluid motion in the vicinity of these particles produces ``ghost rod'' structures that behave like semi-permeable rods in the flow. Since these ghost rods are present due to the system dynamics, perturbations in the boundary conditions lead to variations in the existence and structure of the ghost rods. We discuss these variations and assess the role of ghost rods in mixing over a range of operating conditions for this system. The results suggest that ghost rods can play an important role in mixing for other counter-rotating flows.
Aps Division of Fluid Dynamics Meeting Abstracts, Nov 1, 2008
Pulsed operation of a source and a sink is a classic approach to generating chaotic advection in ... more Pulsed operation of a source and a sink is a classic approach to generating chaotic advection in the unbounded plane. This approach provides motivation for mixing laminar flows in high-aspect-ratio volumes using an arrangement of sources and sinks. In bounded systems the sources and sinks must operate in pairs in order to conserve volume. When the sources and sinks are arranged on the boundary of a circular domain, particle motions are given explicitly by a discrete mapping. This mapping is used to explore the optimal operating parameters for producing chaos with three different source-sink configurations in a circular domain.
Iranian Journal of Pharmaceutical Research, Feb 1, 2015
The present investigation deals with the development of controlled release tablets of salbutamol ... more The present investigation deals with the development of controlled release tablets of salbutamol sulphate using graft copolymers (St-g-PMMA and Ast-g-PMMA) of starch and acetylated starch. Drug excipient compatibility was spectroscopically analyzed via FT-IR, which confirmed no interaction between drug and other excipients. Formulations were evaluated for physical characteristics like hardness, friability, weight variations, drug release and drug content analysis which satisfies all the pharmacopoeial requirement of tablet dosage form. Release rate of a model drug from formulated matrix tablets were studied at two different pH namely 1.2 and 6.8, spectrophotometrically. Drug release from the tablets of graft copolymer matrices is profoundly pH-dependent and showed a reduced release rate under acidic conditions as compared to the alkaline conditions. Study of release mechanism by Korsmeyer's model with n values between 0.61-0.67, proved that release was governed by both diffusion and erosion. In comparison to starch and acetylated starch matrix formulations, pharmacokinetic parameters of graft copolymers matrix formulations showed a significant decrease in Cmax with an increase in tmax, indicating the effect of dosage form would last for longer duration. The gastro intestinal transit behavior of the formulation was determined by gamma scintigraphy, using (99m)Tc as a marker in healthy rabbits. The amount of radioactive tracer released from the labelled tablets was minimal when the tablets were in the stomach, whereas it increased as tablets reached to intestine. Thus, in-vitro and in-vivo drug release studies of starch-acrylate graft copolymers proved their controlled release behavior with preferential delivery into alkaline pH environment.
ABSTRACT We extend the method proposed by Miller and Rouet to formulate analytic solutions for th... more ABSTRACT We extend the method proposed by Miller and Rouet to formulate analytic solutions for the electric potential and field in a one-dimensional plasma satisfying periodic boundary conditions. We have also devised an event-driven algorithm to follow the time evolution of the system and to study its dynamical properties. In a dynamical system, the presence of positive Lyapunov exponents indicates that the system is chaotic. Of particular interest is the value of the largest (maximal) Lyapunov exponent which is usually sufficient to point toward the degree of chaos in the system. Using our new approach for defining the phase-space distance in systems with periodic boundary, we have employed our algorithm to find the largest Lyapunov exponent in the periodic plasma. Results obtained from our algorithm will be discussed with a view to exploring the dependence of chaotic properties of the system on its initial state.
Abstract: Osteoarthritis knee is one of the most prevalent disorders in the Indian subcontinent. ... more Abstract: Osteoarthritis knee is one of the most prevalent disorders in the Indian subcontinent. The wide prevalence and varying features makes it a disease of disguise. Multiple etiological factors have been described. The most recent is genetic contribution in ...
It has shown that passive fluid particles moving on periodic orbits can be used to `stir' a visco... more It has shown that passive fluid particles moving on periodic orbits can be used to `stir' a viscous fluid in a two-dimensional lid-driven cavity that exhibits a figure-eight flow pattern (Stremler & Chen 2007). Fluid motion in the vicinity of these particles produces ``ghost rod'' structures that behave like semi-permeable rods in the flow. Since these ghost rods are present due to the system dynamics, perturbations in the boundary conditions lead to variations in the existence and structure of the ghost rods. We discuss these variations and assess the role of ghost rods in mixing over a range of operating conditions for this system. The results suggest that ghost rods can play an important role in mixing for other counter-rotating flows.
Aps Division of Fluid Dynamics Meeting Abstracts, Nov 1, 2008
Pulsed operation of a source and a sink is a classic approach to generating chaotic advection in ... more Pulsed operation of a source and a sink is a classic approach to generating chaotic advection in the unbounded plane. This approach provides motivation for mixing laminar flows in high-aspect-ratio volumes using an arrangement of sources and sinks. In bounded systems the sources and sinks must operate in pairs in order to conserve volume. When the sources and sinks are arranged on the boundary of a circular domain, particle motions are given explicitly by a discrete mapping. This mapping is used to explore the optimal operating parameters for producing chaos with three different source-sink configurations in a circular domain.
Iranian Journal of Pharmaceutical Research, Feb 1, 2015
The present investigation deals with the development of controlled release tablets of salbutamol ... more The present investigation deals with the development of controlled release tablets of salbutamol sulphate using graft copolymers (St-g-PMMA and Ast-g-PMMA) of starch and acetylated starch. Drug excipient compatibility was spectroscopically analyzed via FT-IR, which confirmed no interaction between drug and other excipients. Formulations were evaluated for physical characteristics like hardness, friability, weight variations, drug release and drug content analysis which satisfies all the pharmacopoeial requirement of tablet dosage form. Release rate of a model drug from formulated matrix tablets were studied at two different pH namely 1.2 and 6.8, spectrophotometrically. Drug release from the tablets of graft copolymer matrices is profoundly pH-dependent and showed a reduced release rate under acidic conditions as compared to the alkaline conditions. Study of release mechanism by Korsmeyer's model with n values between 0.61-0.67, proved that release was governed by both diffusion and erosion. In comparison to starch and acetylated starch matrix formulations, pharmacokinetic parameters of graft copolymers matrix formulations showed a significant decrease in Cmax with an increase in tmax, indicating the effect of dosage form would last for longer duration. The gastro intestinal transit behavior of the formulation was determined by gamma scintigraphy, using (99m)Tc as a marker in healthy rabbits. The amount of radioactive tracer released from the labelled tablets was minimal when the tablets were in the stomach, whereas it increased as tablets reached to intestine. Thus, in-vitro and in-vivo drug release studies of starch-acrylate graft copolymers proved their controlled release behavior with preferential delivery into alkaline pH environment.
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