Showing papers by "Shantanu Das published in 2016"
TL;DR: Optimal pole-zero approximation method in discrete form is proposed for realization of digital fractional order controller and shows better speed control of separately excited DC motor with the realized digital FO-PID controller than that of the integer order PID controller.
Abstract: The aim of paper is to employ digital fractional order proportional integral derivative (FO-PID) controller for speed control of buck converter fed DC motor. Optimal pole-zero approximation method in discrete form is proposed for realization of digital fractional order controller. The stand-alone controller is implemented on embedded platform using digital signal processor TMS320F28027. The five tuning parameters of controller enhance the performance of control scheme. For tuning of the controller parameters, dynamic particle swarm optimization technique is employed. The proposed control scheme is simulated on MATLAB and verified by experimental results. Performance comparison shows better speed control of separately excited DC motor with the realized digital FO-PID controller than that of the integer order PID controller.
69 citations
01 Oct 2016
TL;DR: In this paper, the properties of microwave welded Inconel 718/ austenitic stainless steel (SS-316L) were investigated and the principles of microwave hybrid heating were effective.
Abstract: Microstructure and mechanical properties of microwave welded Inconel 718/ austenitic stainless steel (SS-316L) were investigated in this work. Principles of microwave hybrid heating were effectivel...
41 citations
01 Mar 2016
TL;DR: In this paper, a dissimilar weld between a mild steel and a stainless steel-316 was formed by exposing the candidate materials to electromagnetic radiation in the microwave band, and characterisations of the joints wer...
Abstract: Dissimilar weld between a mild steel and a stainless steel-316 was formed by exposing the candidate materials to electromagnetic radiation in the microwave band. Characterisations of the joints wer...
32 citations
TL;DR: In this paper, a piecewise modeling and parameter estimation approach for ultracapacitors using a hybrid optimization and fuzzy clustering approach is proposed, which is able to represent the experimental data over different operating points with reduced number of model parameters.
29 citations
TL;DR: In this article, the authors established the fractional order Schrodinger equation and its solution in terms of the Mittag-Leffler function with complex arguments, and derived some properties of the FOS for the case of particle in one dimensional infinite potential well.
Abstract: One of the motivations for using fractional calculus in physical systems is due to fact that many times, in the space and time variables we are dealing which exhibit coarse-grained phenomena, meaning that infinitesimal quantities cannot be placed arbitrarily to zero-rather they are non-zero with a minimum length. Especially when we are dealing in microscopic to mesoscopic level of systems. Meaning if we denote x the point in space and t as point in time; then the differentials dx (and dt) cannot be taken to limit zero, rather it has spread. A way to take this into account is to use infinitesimal quantities as (\Deltax)^\alpha (and (\Deltat)^\alpha) with 0 \Deltax. This way defining the differentials-or rather fractional differentials makes us to use fractional derivatives in the study of dynamic systems. In fractional calculus the fractional order trigonometric functions play important role. The Mittag-Leffler function which plays important role in the field of fractional calculus; and the fractional order trigonometric functions are defined using this Mittag-Leffler function. In this paper we established the fractional order Schrodinger equation-composed via Jumarie fractional derivative; and its solution in terms of Mittag-Leffler function with complex arguments and derive some properties of the fractional Schrodinger equation that are studied for the case of particle in one dimensional infinite potential well.
21 citations
TL;DR: In this paper, a simple squeeze flow experiment is performed, where loading is done in two steps with a time lag τ∼ seconds between the steps, and the effect on the strain, of varying τ is reproduced by a three element visco-elastic solid model.
17 citations
TL;DR: The results show that the hybrid algorithm is capable of identifying the model parameters efficiently in both time and frequency domain, and has been found to be dependent on the initial condition, magnitude and offset of the applied voltage.
Abstract: The increasing demand of electrical energy storage has motivated the wide usage of ultracapacitors. Ultracapacitors are capable of storing and delivering energy at a rate much higher than conventional rechargeable batteries. The dynamics characteristics of ultracapacitors are better exhibited by fractional calculus as compared to the conventional calculus. The present work aims at estimating the fractional model parameters of an ultracapacitor using experimental data and further investigating the dependency of fractional parameters on the operating conditions. The parameter estimation task has been formulated as an optimization problem which aims at minimizing the deviation between the model and experimental output using a hybrid optimization technique. The hybrid algorithm combines an improved version of seeker optimization algorithm for global exploration with a local search technique, i.e., Nelder---Mead simplex search. The results show that the hybrid algorithm is capable of identifying the model parameters efficiently in both time and frequency domain. The fractional behavior has been found to be dependent on the initial condition, magnitude and offset of the applied voltage.
14 citations
TL;DR: In this paper, the authors observed wavy cracks and naturally patterned fracture surfaces in drying LAPONITE® paste and provided an insight into the mechanism of wavelength selection under an electric field of sufficient strength.
Abstract: We report observation of wavy cracks and naturally patterned fracture surfaces in drying LAPONITE® paste. Desiccation cracks are shown to follow undulating, corrugated paths even when the speed of crack propagation is lower than the sound velocity in the medium by two orders of magnitude. Fast Fourier transform of the wavy crack path shows that it is a superposition of several sinusoidal modes and their harmonics. When the paste is exposed to a DC electric field during drying, by imposing a 50 V potential, some of the modes are suppressed. Increasing the voltage to 100 V results in survival of only one pure sinusoidal mode of wavelength ∼292 μm. We suggest that an effective mixed mode loading develops as a result of faster evaporation at the upper surface of the paste, and this is responsible for the instability leading to the wavy contour of the crack. The present study provides an insight into the mechanism of wavelength selection under an electric field of sufficient strength. We also show that unstable crack propagation may have similarity with the mechanism that exists in an auxiliary experiment: breaking of a perspex sheet.
5 citations
01 Dec 2016
TL;DR: In this article, the authors address possible application of ultracapacitors for the design of very low frequency (VLF) oscillators and propose an approach that allows design of oscillators for a set of low frequency specifications.
Abstract: In recent years, applications of ultracapacitor in electrical systems have witnessed a rise due to their high power density. Ultracapacitors are known to possess inherent nonlinear dynamics with long term memory, which can be better, described using fractional calculus. This article addresses possible application of ultracapacitors for the design of very low frequency (VLF) oscillators. The presence of fractional dynamics in ultracapacitors has been studied over wide frequency ranges, and utilized to estimate the VLF oscillation frequency. The proposed approach allows design of oscillators for a set of low frequency specifications.
4 citations
TL;DR: In this paper, the effect of random parameter switching in a fractional order (FO) unified chaotic system was investigated. And the authors showed that a noise-like random variation in the key parameter along with a gradual decrease in the commensurate FO is capable of suppressing the chaotic fluctuations much earlier than that with the fixed parameter one.
Abstract: The paper explores the effect of random parameter switching in a fractional order (FO) unified chaotic system which captures the dynamics of three popular sub-classes of chaotic systems i.e. Lorenz, Lu and Chen's family of attractors. The disappearance of chaos in such systems which rapidly switch from one family to the other has been investigated here for the commensurate FO scenario. Our simulation study show that a noise-like random variation in the key parameter of the unified chaotic system along with a gradual decrease in the commensurate FO is capable of suppressing the chaotic fluctuations much earlier than that with the fixed parameter one. The chaotic time series produced by such random parameter switching in nonlinear dynamical systems have been characterized using the largest Lyapunov exponent (LLE) and Shannon entropy. The effect of choosing different simulation techniques for random parameter FO switched chaotic systems have also been explored through two frequency domain and three time domain methods. Such a noise-like random switching mechanism could be useful for stabilization and control of chaotic oscillation in many real-world applications.
4 citations
TL;DR: In this article, the generalized Tanh method was used to find the exact solution of KP-Burger equation and coupled KdV equation and numerical simulation showed that the solution of two fractional differential equations reduces to the classical solution for KP-burger equation when order of fractional derivative tends to one.
Abstract: Evaluation of analytical solutions of non-linear partial differential equations (both classical and fractional) is a rising subject in Applied Mathematics because its applications in Physical biological and social sciences. In this paper we have used generalized Tanh method to find the exact solution of KP-Burger equation and coupled KdV equation. The fractional Sub-equation method has been used to find the solution of fractional KP-Burger equation and fractional coupled KdV equations. The exact solution obtained by fractional sub-equation method reduces to classical solution when order of fractional derivative tends to one. Finally numerical simulation has done. The numerical simulation justifies that the solutions of two fractional differential equations reduces to shock solution for KP-Burger equation and soliton solution for coupled KdV equations when order of derivative tends to one.
Journal Article•
TL;DR: The solution of non-linear differential equation, nonlinear partial differential equation and nonlinear fractional differential equation is a current research in Applied Science as discussed by the authors, and the solution of these equations is reported in analytical traveling wave solution form.
Abstract: The solution of non-linear differential equation, non-linear partial differential equation and non-linear fractional differential equation is current research in Applied Science. Here tanh-method and Fractional Sub-Equation methods are used to solve three non-linear differential equations and the corresponding fractional differential equation. The fractional differential equations here are composed with Jumarie fractional derivative. Both the solution is obtained in analytical traveling wave solution form. We have not come across solutions of these equations reported anywhere earlier.
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TL;DR: In this article, the authors carried out numerical simulation and experimental characterization of two variants of SR (Spiral resonator) viz. TTSR (Two-Turn Spiral Resonator) and NBSR (Non Bianisotropic spiral resonator).
Abstract: In this paper we have carried out numerical simulation and experimental characterization of two variants of SR (Spiral resonator) viz. TTSR (Two-Turn Spiral Resonator) and NBSR (Non Bianisotropic spiral resonator). The numerical simulation of these develop magnetic inclusion structures are done with commercially available Finite Element Method (FEM) based Ansys HFSS-13 simulation software, and transmission experiment using S-parameter retrieval technique. The experimental characterization of those fabricated structures is used in the parallel plate waveguide experiment (not reported earlier) and then validate our experimental results with the Ansys HFSS-13 simulation software; which in not available in any published literature.
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TL;DR: In this paper, the negative refractive index (NRM) was measured in the Ka band using LR labyrinth ring and wire array in a negative angle of refraction (AoR) at 1 G Hz around 31 GHz.
Abstract: In this paper, we discuss the experimental characterization of a negative refractive material NRM at Ka band using LR labyrinth Ring and wire array WA. We describe in detail the the LR and wire array characterization separately, and after that the combined experimental results, for NRM are reported. The LRs analytical and simulation study is not new but design in Ka band and different experimental procedure for the characterization of the negative refractive index is the novelty of this paper. For performing a negative refractive index experiment we made prism of 150 Prism angle . We get enhanced transmittance of more than 20 dB from background, at a negative angle of refraction. The values of the negative refractive index in a band of about 1 G Hz around 31 GHz are retrieved from the experimental data.
TL;DR: In this article, the generalized Tanh method was used to find the exact solution of KP-Burger equation and coupled KdV equation and numerical simulation showed that the solution of two fractional differential equations reduces to the classical solution for KP-burger equation when order of fractional derivative tends to one.
Abstract: Evaluation of analytical solutions of non-linear partial differential equations (both classical and fractional) is a rising subject in Applied Mathematics because its applications in Physical biological and social sciences. In this paper we have used generalized Tanh method to find the exact solution of KP-Burger equation and coupled KdV equation. The fractional Sub-equation method has been used to find the solution of fractional KP-Burger equation and fractional coupled KdV equations. The exact solution obtained by fractional sub-equation method reduces to classical solution when order of fractional derivative tends to one. Finally numerical simulation has done. The numerical simulation justifies that the solutions of two fractional differential equations reduces to shock solution for KP-Burger equation and soliton solution for coupled KdV equations when order of derivative tends to one.