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Shantanu Das

Bio: Shantanu Das is an academic researcher from Bhabha Atomic Research Centre. The author has contributed to research in topics: Fractional calculus & PID controller. The author has an hindex of 24, co-authored 152 publications receiving 2925 citations. Previous affiliations of Shantanu Das include University of Chicago & Jadavpur University.


Papers
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Proceedings ArticleDOI
01 Dec 2011
TL;DR: In this paper, the impact of the independent parameters of the hybrid differentiator on the phase response has been depicted along with the achievable accuracies for increasing order of realization for filter design.
Abstract: Rational approximation of fractional order (FO) elements are now of prime importance for the need of its hardware implementation in control design and signal processing. Among the well known analog realizations methods, the Carlson's approach has been used in this paper due to its simplicity of calculation for designing a certain class of FO differentiators as hybrid filters. Impact of the independent parameters of the hybrid differentiator on the phase response has been depicted along with the achievable accuracies for increasing order of realization for filter design.

7 citations

Proceedings ArticleDOI
01 Dec 2011
TL;DR: In this paper, a nonlinear nuclear reactor model is linearized at different initial powers for the purpose of controlling the reactor in load following mode and a new fractional order (FO) fuzzy proportional integral derivative (PID) controller is tuned next using GA to control the reactor at different operating conditions.
Abstract: A nonlinear nuclear reactor model is linearized at different initial powers for the purpose of controlling the reactor in load following mode A new fractional order (FO) fuzzy proportional integral derivative (PID) controller is tuned next using Genetic Algorithm (GA) to control the reactor at different operating conditions The effectiveness of using the fuzzy FOPID controller over conventional fuzzy PID controllers is shown with credible numerical simulations The controllers tuned with the highest and lowest power models are shown to work well at other operating conditions also and hence are robust with respect to the changes in nuclear reactor power level

7 citations

Posted ContentDOI
TL;DR: In this paper, a method to solve the linear non-homogeneous fractional differential equations (FDE), composed with Jumarie type Fractional Derivative, and describe this method developed by us, to find out particular integral, for several types of forcing functions.
Abstract: In this paper we describe a method to solve the linear non-homogeneous fractional differential equations (FDE), composed with Jumarie type Fractional Derivative, and describe this method developed by us, to find out Particular Integrals, for several types of forcing functions. The solutions are obtained in terms of Mittag-Leffler functions, fractional sine and cosine functions. We have used our earlier developed method of finding solution to homogeneous FDE composed via Jumarie fractional derivative, and extended this to non-homogeneous FDE. We have demonstrated these developed methods with few examples of FDE, and also applied in fractional damped forced differential equation. This method proposed by us is useful as it is having conjugation with the classical methods of solving non-homogeneous linear differential equations, and also useful in understanding physical systems described by FDE.

7 citations

Book ChapterDOI
01 Jan 2011
TL;DR: In this article, an identification method based on continuous order distribution, is discussed, which is suitable for both the standard integer order and fractional order systems, is demonstrated using assumption that system order distribution is a continuous one.
Abstract: For unknown systems, ‘system identification’ has become the standard tool of the control engineer and scientists. Identifying a given system from data becomes more difficult, however when fractional orders are allowed. Here identification process is demonstrated using assumption that system order distribution is a continuous one. Frequency domain system identification can thus be performed using numerical methods demonstrated in this chapter. Here one concept of r-Laplace transforms is discussed (Laplace transform in log domain), to discuss the system order distribution. Also mentioned is variable order identification as further development where the system order also varies with ambient and time is highlighted. Here in this chapter, an identification method based on continuous order distribution, is discussed. This technique is suitable for both the standard integer order and fractional order systems. This is topic for further advance research as to qualify the procedure of system order identification and to have technique of tackling variable order. Extending this continuous order distribution discussion, the advance research of having a continuum order feedback and generalized PID control is elucidated. Also in this chapter some peculiarities of the pole property of fractional order system as ultra-damping, hyper-damping and fractional resonance is explained. Elaborate research in this direction is ongoing process; to crisply define the system identification, crisply define the variable order structure, along with generalized controller for future applications. The system identification in presence of disorder is what is challenging and some unification of disordered time-response that is relaxation is too discussed. This is general process of returning to equilibrium for say any stable system or properties of condense matter physics. The introduction to complex order calculus in system identification is too touched upon, in this chapter, along with identification of main parameters of ‘irregular’ stochastically behaving systems.

7 citations

01 Jan 2012
TL;DR: In this paper, the authors tried to explain the insight of electromagnetic field penetration into spherical conductive powder particles and its spatial oscillatory distribution, and gave insight as to how the entire weld zone volume becomes heat source via absorption of microwave radiation, and thus this process of welding with microwave radiation is with inertia less heat transfer, volumetric heating with inverted temperature profile.
Abstract: We have been successfully welding bulk metals and dissimilar metals by microwave radiation, by using metal powder particles in the weld zone. In this paper, we have tried to explain the insight of electromagnetic field penetration into spherical conductive powder particles and its spatial oscillatory distribution. This new developed theoretical explanation here, gives insight as to how the entire weld zone volume becomes heat source; via absorption of microwave radiation, and thus this process of welding with microwave radiation, is with inertia less heat transfer, volumetric heating with inverted temperature profile.

7 citations


Cited by
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Book ChapterDOI
01 Jan 2015

3,828 citations

01 Nov 2000
TL;DR: In this paper, the authors compared the power density characteristics of ultracapacitors and batteries with respect to the same charge/discharge efficiency, and showed that the battery can achieve energy densities of 10 Wh/kg or higher with a power density of 1.2 kW/kg.
Abstract: The science and technology of ultracapacitors are reviewed for a number of electrode materials, including carbon, mixed metal oxides, and conducting polymers. More work has been done using microporous carbons than with the other materials and most of the commercially available devices use carbon electrodes and an organic electrolytes. The energy density of these devices is 3¯5 Wh/kg with a power density of 300¯500 W/kg for high efficiency (90¯95%) charge/discharges. Projections of future developments using carbon indicate that energy densities of 10 Wh/kg or higher are likely with power densities of 1¯2 kW/kg. A key problem in the fabrication of these advanced devices is the bonding of the thin electrodes to a current collector such the contact resistance is less than 0.1 cm2. Special attention is given in the paper to comparing the power density characteristics of ultracapacitors and batteries. The comparisons should be made at the same charge/discharge efficiency.

2,437 citations

01 Sep 2010

2,148 citations

Book ChapterDOI
11 Dec 2012

1,704 citations

Book ChapterDOI
01 Jan 2014
TL;DR: In this paper, Dzherbashian [Dzh60] defined a function with positive α 1 > 0, α 2 > 0 and real α 1, β 2, β 3, β 4, β 5, β 6, β 7, β 8, β 9, β 10, β 11, β 12, β 13, β 14, β 15, β 16, β 17, β 18, β 20, β 21, β 22, β 24
Abstract: Consider the function defined for \(\alpha _{1},\ \alpha _{2} \in \mathbb{R}\) (α 1 2 +α 2 2 ≠ 0) and \(\beta _{1},\beta _{2} \in \mathbb{C}\) by the series $$\displaystyle{ E_{\alpha _{1},\beta _{1};\alpha _{2},\beta _{2}}(z) \equiv \sum _{k=0}^{\infty } \frac{z^{k}} {\varGamma (\alpha _{1}k +\beta _{1})\varGamma (\alpha _{2}k +\beta _{2})}\ \ (z \in \mathbb{C}). }$$ (6.1.1) Such a function with positive α 1 > 0, α 2 > 0 and real \(\beta _{1},\beta _{2} \in \mathbb{R}\) was introduced by Dzherbashian [Dzh60].

919 citations