Biomedical subjects

D Salin

Publications and source records attributed to D Salin.

13 recordsLinked to original sources

PubMed2004

Crossing the elliptic region in a hyperbolic system with change-of-type behavior arisingin flow between two parallel plates.

Change-of-type behavior from hyperbolic to elliptic is common to quasilinear hyperbolic systems. This issue is addressed here for the particular case of miscible flow of three fluids between two parallel plates. Change of type occurs at the leading edge of the displacement front and reflects the failing of the equilibrium assumption, necessary for the quasilinear hyperbolic formalism, at the front. To cross the elliptic region requires the solution of the full, higher-dimensionality problem, obtained here using lattice gas simulations. For the specific example, it is found that the system self-selects a front structure independent of injection conditions.

Journal Article↗

PubMed2004

Mixing and reaction fronts in laminar flows.

Autocatalytic reaction fronts between unreacted and reacted mixtures in the absence of fluid flow propagate as solitary waves. In the presence of imposed flow, the interplay between diffusion and advection enhances the mixing, leading to Taylor hydrodynamic dispersion. We present asymptotic theories in the two limits of small and large Thiele modulus (slow and fast reaction kinetics, respectively) that incorporate flow, diffusion, and reaction. For the first case, we show that the problem can be handled to leading order by the introduction of the Taylor dispersion replacing the molecular diffusion coefficient by its Taylor counterpart. In the second case, the leading-order behavior satisfies the eikonal equation. Numerical simulations using a lattice gas model show good agreement with the theory. The Taylor model is relevant to microfluidics applications, whereas the eikonal model applies at larger length scales.

Journal Article↗

PubMed2003

Pattern of reaction diffusion fronts in laminar flows.

Autocatalytic reaction between reacted and unreacted species may propagate as solitary waves, namely, at a constant front velocity and with a stationary concentration profile, resulting from a balance between molecular diffusion and chemical reaction. The effect of advective flow on the autocatalytic reaction between iodate and arsenous acid in cylindrical tubes and Hele-Shaw cells is analyzed experimentally and numerically using lattice Bhatnagar-Gross-Krook simulations. We do observe the existence of solitary waves with concentration profiles exhibiting a cusp and we delineate the eikonal and mixing regimes recently predicted.

Animals↗

PubMed2002

Buoyancy-driven instability of an autocatalytic reaction front in a Hele-Shaw cell.

An autocatalytic reaction-diffusion front between two reacting species may propagate as a solitary wave, namely, at constant velocity and with a stationary concentration profile. Recent experiments on such reactions have been reported to be buoyancy unstable, under certain conditions. We calculate the linear dispersion relation of the resulting instability, by applying our recent analysis of the Rayleigh-Taylor instability of two miscible fluids in a Hele-Shaw cell. The computed dispersion relation as well as our three-dimensional lattice Bhatnagar-Gross-Krook (BGK) simulations fit reasonably well experimental growth rates reported previously.

Journal Article↗

PubMed2001

[Strength training with superimposed vibrations].

To examine the effects of strength training with superimposed vibrations ten subjects trained over a period of six weeks (three sessions per week) one leg with back squats and superimposed vibrations and the other leg with traditional squats. In each training session participants performed 4 sets with 8-12 repetitions. Before and after the training period maximum strength and rate of force development were measured. The results show that both training modes induced comparable and statistical significant increases in maximum strength (vibration training +6.5%, traditional training +6.2%. The slight increases in rate of force development in both groups didn't reach statistical significance. As a consequence it seems that strength training with superimposed vibrations for the leg extensor chain is not superior to a traditional training mode.

Adult↗

PubMed1995