Publications by authors named "Muktish Acharyya"

In the present paper, we investigate the effects of disorder on the reversal time (τ) of classical anisotropic Heisenberg ferromagnets in three dimensions by means of Monte Carlo simulations. Starting from the pure system, our analysis suggests that τ increases with increasing anisotropy strength. On the other hand, for the case of randomly distributed anisotropy, generated from various statistical distributions, a set of results is obtained: (i) For both bimodal and uniform distributions, the variation of τ with the strength of anisotropy strongly depends on temperature.

View Article and Find Full Text PDF

We present an extensive Monte Carlo investigation of the metastable lifetime through the reversal of the magnetization of spin-s Ising and Blume-Capel models, where s={1/2,1,3/2,2,5/2,3,7/2}. The mean metastable lifetime (or reversal time) is studied as a function of the applied magnetic field, and for both models it is found to obey the Becker-Döring theory, as was initially developed for the case of an s=1/2 Ising ferromagnet within the classical nucleation theory. Moreover, the decay of the metastable volume fraction nicely follows Avrami's law for all values of s and for both models considered.

View Article and Find Full Text PDF

We report the results of the magnetisation reversal in Ising ferromagnet having thermal and field gradients by Monte Carlo simulation. We have studied the distribution of reversal times for different values of thermal and field gradients and compared the results with those obtained for uniform temperature. The movement of the domain wall of distinct domains and the growth of roughness of domain wall have also been studied statistically.

View Article and Find Full Text PDF

The spin wave interference is studied in two dimensional Ising ferromagnet driven by two coherent spherical magnetic field waves by Monte Carlo simulation. The spin waves are found to propagate and interfere according to the classic rule of interference pattern generated by two point sources. The interference pattern of spin wave is observed in one boundary of the lattice.

View Article and Find Full Text PDF

We study the dynamics of the paradigmatic Kuramoto-Sakaguchi model of identical coupled phase oscillators with various kinds of time-dependent connectivity using Eulerian discretization. We explore the parameter spaces for various types of collective states using the phase plots of the two statistical quantities, namely, the strength of incoherence and the discontinuity measure. In the quasistatic limit of the changing of coupling range, we observe how the system relaxes from one state to another and identify a few interesting collective dynamical states along the way.

View Article and Find Full Text PDF

Background: Brickfield workers in India perform manual materials handling (MMH) and as a result, are at a high risk of developing oxidative stress. This results in an alteration of the various markers of metabolic oxidative stress at the cellular level. Since red blood cell (RBC) is the central point where oxygen, glucose-6-phosphate dehydrogenase (G-6-PD), and glutathione (GSH) are involved, the surface roughness and its alteration and modeling with respect to workers exposed to MMH may be considered as helpful determinants in predicting early damage to the cell and restoring better health to the exposed population, that is, the worker exposed to stress.

View Article and Find Full Text PDF

Strenous physical exercise like professional load bearing often produces oxidative stress, increasing post exercise Malondialdehyde (MDA) levels. To quantify the cellular dimension/profile of the said stress, nanoscopic observation of the erythrocyte surface was made by Atomic Forced Microscopy (AFM)/Lateral Forced Microscopy (LFM) and correspondingly the average roughness of the surface was measured. An attempt has been made to correlate the antioxidant vitamin mixture supplementation, endurance capacity, allied physiological parameters and blood glucose-6-phosphate dehydrogenase (G-6-PD) level and roughness-MDA correlation and thereby the deduced regression equation as crucial markers of performance related oxidative stress management in professional female load bearers.

View Article and Find Full Text PDF

A uniaxially (along the Z axis) anisotropic Heisenberg ferromagnet, in the presence of time-dependent (but uniform over space) magnetic field, is studied by Monte Carlo simulation. The time-dependent magnetic field was taken as elliptically polarized where the resultant field vector rotates in the X-Z plane. The system is cooled (in the presence of the elliptically polarized magnetic field) from high temperature.

View Article and Find Full Text PDF