University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

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It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

Applied Mathematics

The problem of water wave propagation over a rectangular submarine trench in the presence of a thin vertical partially immersed barrier for its three different positions are investigated here assuming linear theory. For each position of the barrier, the problem is reduced to solving three weakly singular integral equations of first kind involving horizontal component of velocity above the two edges of the trench and below the barrier. The integral equations are solved employing Galerkin approximation in terms of simple polynomials multiplied by appropriate weight functions whose forms are dictated by the edge conditions at the corners of the trench and at the submerged end of the barrier. The numerical estimates for reflection and transmission coefficients are depicted graphically against the wave number for different lengths and positions of the barrier. © 2021 The Japan Society of Fluid Mechanics and IOP Publishing Ltd.

World University root node

Fluid Dynamics Research

Wave propagation over a rectangular trench in the presence of a partially immersed barrier

The traditional model-driven methods are not much efficient to predict the viscosity of nanofluids accurately. This study presents a novel approach of using physics-guided deep learning technique for predicting viscosity of water-based nanofluids from large dataset containing both experimental and simulated data of spherical oxide nanoparticles Al2O3, CuO, SiO2, and TiO2. Further, this study introduces a novel methodology of combining deep learning methods and physics-based models to leverage their complementary strengths. To the best of the author’s knowledge, theory-guided deep learning prediction model was never used to predict viscosity before. The theory-guided deep neural networks (TGDNN) model is trained by minimizing the mean square error (MSE) and regularization terms using Adam optimization technique. The investigations reveal that the values of R2, RMSE, and AARD% are, respectively, 0.999868, 0.001143, and 2.198887 on experimental testing dataset. The TGDNN model learns non-linear relationship among the input variables from the training data. Additionally, the results show that the proposed method performed better than the other well-known existing theoretical and computer-aided models to predict the viscosity in wide range with high level of accuracy. © 2021

Fulltext

Journal of Computational Design and Engineering

Physics-based smart model for prediction of viscosity of nanofluids containing nanoparticles using deep learning

A model of oblique wave diffraction by multiple arbitrary porous barriers in infinitely deep water is proposed to study the role of the porous breakwater in mitigating wave effects and dissipating wave energy. The Havelock's expansion of water wave potential along with suitable matching conditions and the single term Galerkin approximation method are used to handle the mathematical boundary value problem. The role of the arbitrary porous barrier is studied by analyzing the reflection coefficient, dissipated energy, and wave forces on the barriers. Significant changes are found in wave reflection and forces due to the consideration of porous barriers as compared to rigid barriers in the fluid region. As the separation length between the vertical barriers increases, the reflection coefficient becomes oscillatory as a function of the wavenumber, which is due to multiple reflections by the barriers. It is seen that the wave load reduces significantly with an increase in the number of barriers. It is also found that more energy is dissipated if the permeability of the barriers is increased. The correctness of the present method is confirmed by comparing the results available in the literature. © 2021 Informa UK Limited, trading as Taylor & Francis Group.

Waves in Random and Complex Media

Mitigation of wave force and dissipation of energy by multiple arbitrary porous barriers

This article presents the peristaltic transport of an incompressible Williamson nanofluid through the asymmetric inclined annular channel. Our present model is determined for blood flow containing nanoparticles in a gap between two coaxial tubes. Further, this study carried out a novel approach of single and discrete phase model of gold nanoparticles. The effects of magnetic field, thermophoresis, and Brownian force are taken into consideration to develop the model. Exact solutions for temperature distribution and nanoparticles concentration are evaluated, whereas Homotopy Perturbation Method (HPM) is used to determine the approximate analytical solution for the velocity distribution. The outcomes are discussed through figures against different pertinent flow parameters. The graphical discussion of trapping phenomena and the distribution of nanoparticles are disclosed elaborately. The results of the present study will provide characteristic knowledge of nanoparticles for deposition and intended distribution of drugs in the presence of a catheter. © 2021 Informa UK Limited, trading as Taylor & Francis Group.

International Journal of Ambient Energy

Combined impact of Brownian motion and thermophoresis on nanoparticle distribution in peristaltic nanofluid flow in an asymmetric channel

In the present manuscript, a two-dimensional generalized thermoelastic model is used to study the problem of reflection of thermoelastic plane waves from a stress-free and thermally insulated boundary of thermally conducting isotropic homogeneous elastic material. The Lord–Shulman model under the heat transfer law with memory-dependent derivative is employed to model this problem. The case of total reflection is taken into account to calculate the critical angle. Phase velocities and corresponding attenuation factors of the coupled dilatational elastic-thermal waves and the ratios of the reflection coefficients are calculated and illustrated graphically for copper-like material and highlighted the effects of various parameters of interest. © 2020, Indian Association for the Cultivation of Science.

Indian Journal of Physics

Reflection of thermoelastic plane waves at a stress-free insulated solid boundary with memory-dependent derivative

Isolation and quarantine play important role to control dengue outbreak but much attention has not yet been paid to develop dengue models with these control factors. In this paper, we have developed a SEIQR- SEI type compartmental dengue model with the effect of isolation. The model has one locally asymptotically stable disease free equilibrium (DFE) point when the basic reproduction number is less than unity. The model without dengue induced death has a globally asymptotically stable DFE point when the corresponding basic reproduction number is less than unity and a globally asymptotically stable endemic equilibrium point when the basic reproduction number is greater than unity. The model exhibits backward bifurcation when the basic production number is equal to one and the first bifurcation coefficient is greater than zero. The key model parameters have been estimated by fitting the model to the dengue outbreak data reported from Singapore during the period 18th week to 53th week,2014. The findings suggest that the total outbreak size reduces by 32.87%, 27.02% and 35.96% respectively when the isolation rate increases from 0 to 0.5, the mosquito biting rate reduces from 1.235 to 1.00 and the vector control rate increases from 0.038 to 0.090. Using sensitivity analysis, we have determined the most sensitive model parameters. © 2021, The Author(s), under exclusive licence to Springer Nature India Private Limited.

International Journal of Applied and Computational Mathematics

The Role of Isolation and Vector Control in the Prevention of Dengue: A Case Study of 2014 Dengue Outbreak in Singapore

arXiv preprint arXiv:2110.

Role of assortativity in predicting burst synchronization using echo state network

arXiv e-prints, arXiv: 2107.

Arbitrary Measurement dependence in tripartite non-locality

In this work, we have developed a three-dimensional gravitational model of barred galaxies, in order to study orbital and escape dynamics of the stars inside their central barred region. Our gravitational model is composed of four components: central bulge, bar, disc and dark matter halo. Furthermore, we have analysed the model for two different types of bar potentials. The study has been carried out for a Hamiltonian system, and thorough numerical investigations has been done in order to explore the regular and chaotic motions of stars. We have seen that escape mechanism has only seen near saddle points (L1, L2 and L1′, L2′) of the Hamiltonian system. Orbital structures in the x- y plane indicate that this escaping motion corresponds to the two ends of the bar. Classifications of orbits are found by calculating maximal Lyapunov exponent of the stellar trajectories corresponding to a specific initial condition vector. Poincaré surface section maps are studied in both the x- y and x- px (px is the momentum along the x-direction) planes to get a complete information about the escape properties of the system in the phase space. Also, we studied in detail how the chaotic dynamics varies with the mass, length and nature of the bar. We found that under suitable physical conditions the chaos plays a pivotal role behind the formation of grand design or less prominent spiral patterns for stronger bars and ring structures for weaker bars. © 2021, The Author(s), under exclusive licence to Springer Nature B.V.

Celestial Mechanics and Dynamical Astronomy

Role of galactic bars in the formation of spiral arms: a study through orbital and escape dynamics—I

Herein we explore the effects of three-phase-lag (TPL) model of generalized thermoelasticity on the exact analysis of three-dimensional free vibrations of viscothermoelastic solid cylinder, which is assumed undeformed initially and at uniform temperature. The formulation has been put into practice with three different phase-lag parameters i.e., Phase-lag of the heat flux, Phase-lag of the temperature gradient, and Phase-lag of the thermal displacement gradient. The solution of matrix Frobenius method of continued series solution has been implemented to solve the differential equations for the evaluation of field functions i.e. stresses, displacements, and temperature by applying stress-free/rigidly-fixed thermal boundary conditions (i.e. thermally insulated and isothermal). The obtained frequency equations for the existence of different modes of TPL viscothermoelastic solid cylinder have been developed using considered stress free/rigidly fixed boundary conditions. The free vibration field functions i.e. frequency shift and thermoelastic damping have been presented graphically from the data generated by simulations and computations of numerical results. Also, the natural frequencies are presented in the form of tables which shows that with an increase in the axial wave-number and length to radius ratio, the behavior of vibrations goes on increasing. The behavior of vibrations of field functions in case of TPL model has larger in contrast to other models of generalized thermoelasticity. © 2020