arXiv subjects

S. Chakraverty

Publications and source records attributed to S. Chakraverty.

21 records · Page 2Linked to original sources

arXiv2007

Response Prediction of Structural System Subject to Earthquake Motions using Artificial Neural Network

This paper uses Artificial Neural Network (ANN) models to compute response of structural system subject to Indian earthquakes at Chamoli and Uttarkashi ground motion data. The system is first trained for a single real earthquake data. The trained ANN architecture is then used to simulate earthquakes with various intensities and it was found that the predicted responses given by ANN model are accurate for practical purposes. When the ANN is trained by a part of the ground motion data, it can also identify the responses of the structural system well. In this way the safeness of the structural systems may be predicted in case of future earthquakes without waiting for the earthquake to occur for the lessons. Time period and the corresponding maximum response of the building for an earthquake has been evaluated, which is again trained to predict the maximum response of the building at different time periods. The trained time period versus maximum response ANN model is also tested for real earthquake data of other place, which was not used in the training and was found to be in good agreement.

cs.AI↗

arXiv2005

"Stochastic Modeling of Coercivity " - A Measure of Non-equilibrium State

A typical coercivity versus particle size curve for magnetic nanoparticles has been explained by using the Gilbert equation followed by the corresponding Fokker Plank equation. Kramer's treatment has been employed to explain the increase in coercivity in the single domain region. The single to multi-domain transformation has been assumed to explain the decrease in coercive field beyond a certain particle size. The justification for using Langevin theory of paramagnetism (including anisotropy energy) to fit the M vs H curve is discussed. The super-symmetric Hamiltonian approach is used to find out the relaxation time for the spins (making an angle greater than $90^0$ with applied field) at domain wall. The main advantage of our technique is that we can easily take into account the time of measurement as we usually do in realistic measurement.

cond-mat.stat-mech↗

arXiv2005

The effect of a weak ferromagnetic matrix on a system of nanomagnetic particles

The study of system of magnetic nano-particle has received increasing attention recently both because of the novel physical concepts involved and also because of their vast potential for application. The influence of background material (the substrate coating) on magnetic properties of such systems is a relatively open topic and often a full understanding is missing. In the present work we discuss our experiments and interpretation for two systems: Ni nanoparticles coated with graphitic carbon and Ni nanoparticles coated with Au. While the latter system exibits behavior typical of superparamagnetic particle systems the former shows several puzzling results such as extremely high blocking temperature ($T_{B}$), very fast relaxation time well below $T_{B}$, temperature independent field-cooled magnetization and very small coercivity and remanent magnetization. We interpret these findings as being a result of weak ferromagnetism, characteristic of the graphitic carbon. This induces strong magnetic interactions between the Ni particles in the presence of small magnetic fields. Such systems give rise to a dramatic difference in blocking temperature between measurements performed at zero field and those performed at very small magnetic fields.

cond-mat.mtrl-sci↗