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Papers by Sucharita Bhattacharyya

Waste Management and Resource Efficiency, 2018

The rapid growth of worldwide population and urbanization is a significant challenge for the Glob... more The rapid growth of worldwide population and urbanization is a significant challenge for the Global Waste Management Industry including Solid Waste Management System (SWMS). Being a responsible citizen and teaching professional at a self-financing institute of technology, located at Panihati, a suburb near Kolkata, the author is also very much concerned about the issue. Very poor SWMS outside the institute campus under A category Panihati Municipality within Kolkata Metropolitan Area (KMA) creating horrible and absolutely unhygienic environmental condition and the lush green, clean campus inside as maintained by the institute owner, creates such a contrasting scenario that the present study is undertaken to unveil the reasons behind. The study is executed in two parts. In the first part, detailed survey is conducted on the existing facilities of Panihati Municipality SWMS including manpower resources, the management techniques, associated technologies and their utilization through the segregation, collection, transportation, treatment and disposal for generated amount of solid wastes to make pollution-free environment in the locality. The relevant data is obtained from Panihati Municipality and individual field visit. The study reveals several lacunas in the existing government-run system. In the second part, the SWMS of an educational campus in Panihati Municipality area is highlighted. It is interesting to mention that in the same campus, there are Dental College and Hospital, Hotel Management Institute, Pharmaceutical Institute and Engineering College along with the students' hostel and staff quarters which are growing day by day. So an well-planned management system for generated Clinical and Pharmaceutical Wastes, Food Wastes, E-wastes and Constructional Wastes-the well known solid

2018 3rd International Conference on Microwave and Photonics (ICMAP)

An accurate and explicit semi vectorial magnetic (H) field mode solver is used for a specific rib... more An accurate and explicit semi vectorial magnetic (H) field mode solver is used for a specific rib wave guide based on Fourth Order Compact Finite Difference Method in combination with Conjugate Gradient algorithm. Here optical waveguide modeling is studied by incorporating the effective refractive index concept of the semi conductor rib wave guide structure for simulating the performances of diverse photonic integrated circuits(PICs). Computed normalized indices and modal indices in both Hx and H modes for different materials are observed to be consistent and in excellent agreement with other published results.

Advances in Communication, Devices and Networking, 2021

An accurate and efficient polarized mode solver in the form of a higher (fourth) order compact fi... more An accurate and efficient polarized mode solver in the form of a higher (fourth) order compact finite difference method (FDM) along with the successive over-relaxation technique is presented here for transverse magnetic or TM mode analysis of propagating electromagnetic waves through rib-structured GaAs and GeSi waveguides. For analysis of performances of such waveguides, the effective index concept has been identified as a key parameter. Accordingly, modal/effective index, normalized index and modal birefringence parameters are introduced in the present study and their obtained values show close agreement with other published data. Most significantly, the scheme successfully identified the optimized values of used waveguide structure parameters and explained their importance in the efficient propagation of transverse electromagnetic waves which might play a crucial role in the fabrication of such waveguides.

Rapid urbanization with human-altered natural conditions results not only in proliferation of inf... more Rapid urbanization with human-altered natural conditions results not only in proliferation of infrastructures but includes pollution and generalized habitat destruction as well. This loss in biodiversity potentially leads to the disappearance of natural processes. As an example, the disruption in regulatory ecosystem services provided by the vultures, world’s most efficient scavenger species by removing the dead animals is worth mentioning at this point. Their precipitous decline over past few decades has speeded up largely and become alarming because of their consumption of carcasses treated with man-made anti-inflammatory drug diclofenac, identified lethal for them in 2003. These affect their long-term mutual relationship with human globally. The disappearance of vultures whose metabolism is a true dead-end for pathogens poses a serious challenge in the management of natural dead animal disposal system beyond urban boundaries. This has allowed additionally some alien species of de...

Acta Scientific Pharmaceutical Sciences, 2021

Lecture Notes in Networks and Systems, 2017

In this paper, we accomplish a comprehensive study of optical waveguide modeling incorporating mo... more In this paper, we accomplish a comprehensive study of optical waveguide modeling incorporating modal index concept in refractive index profile for two specific rib waveguide structures using fourth-order finite difference method in combination with Newton–Krylov subspace algorithm. The numerical results verify the behavior of this higher order compact (HOC) approximations for stability and convergence with least computational time. Obtained results for normalized indices and modal indices are compared with other methods to verify the accuracy and efficiency of the simple scheme used. Also variations of these indices with waveguide structure parameters help to identify their optimized values for efficient wave propagation which are found to be material dependent.

Journal of Optics, 2019

Following the recent success with polarized Efield solutions, an efficient and highly accurate se... more Following the recent success with polarized Efield solutions, an efficient and highly accurate semi-vectorial H-field mode solver is proposed for various rib waveguides based on higher (fourth)-order compact FDM in combination with a conjugate gradient (CG) type of iteration. Here, optical waveguide modeling is designed by incorporating the modal index and modal birefringence concept into the refractive index profiles (RIPs) of two specific semiconductor (GaAs/GaAlAs and GeSi) rib waveguide structures for simulating the performances of various photonic integated circuits and corresponding field profiles of guided modes are shown through the surface and contour plots. It is to be confirmed that the used algorithm takes full account of vertical and horizontal discontinuities of RIPs in cell interfaces within the specific waveguide structure where the numerical results ensure its behavior for stability and convergence with less computational time. For H x and H y modes, computed modal index and normalised index values are found to be in perfect agreement with other published results. Most importantly, the variations of these indices with waveguide structure parameters help to identify their optimized values which play very decisive role so far as their fabrications are concerned. Also study of confinement factor computation and modal birefringence provides some important additional deep understanding with which the optimized index values clearly verify the material dependence for effective wave propagation.

Advanced Studies in Theoretical Physics, 2015

Semi Conductor Optical waveguides, being the basis of active and passive devices are widely used ... more Semi Conductor Optical waveguides, being the basis of active and passive devices are widely used in the field of integrated optics. Main advantages of such wave guides are their well defined refractive index profiles and geometric shapes, with high controllability and reproducibility which help to understand the propagation properties in such wave guides more appropriately. Here rib wave guides are considered as this structure allows the greatest versatility in device design though it is relatively easy to fabricate. The basic concept of the waveguide design employed here is its compositional changes to determine the refractive index profile in the vertical direction where the three regions of the rib structure are divided into zones with specific refractive indices. As for these types of structures no precise analytic solution is obtained, different numerical techniques have been implemented for their study in terms of their modal analysis. Accordingly, an accurate Higher Order Compact (HOC) Finite Difference Method (FDM) is applied here for the investigation of refractive index profile of GaAs and GeSi rib wave guide structure to show their effect on transmission properties of the guided wave using Helmholtz wave equation. The difference in surface and contour plots of the polarized E-field solution clearly show the material dependence on transmitted waves. As strong optical field concentration with high optical confinement and power density in small volume is of great importance for guided-wave optoelectronic devices, we have also studied the variation of optical confinement factor with no. of parameters to understand the propagation properties appropriately.

Applied Mathematical Sciences, 2014

In this paper an accurate Higher Order Compact (HOC) (here, fourth order) finite difference metho... more In this paper an accurate Higher Order Compact (HOC) (here, fourth order) finite difference method (FDM) is used to determine polarized E-field solution in the guiding region of a rib wave guide structure for uniform grids starting with Helmholtz wave equation. This general, absolutely new approach in the area of guided-wave optics is tested in terms of surface and contour plots of the electric field profiles and compared to the existing methods.

2015 IEEE International Conference on Research in Computational Intelligence and Communication Networks (ICRCICN), 2015

In this paper we accomplish a comprehensive study of three different numerical solution technique... more In this paper we accomplish a comprehensive study of three different numerical solution techniques based on semi vectorial Higher Order(4th order) Compact(HOC)Finite Difference Method (FDM) for rib-structured optical wave guide modeling. We have used iterative schemes using the Successive Over Relaxation (SOR), the Steepest Descent (SD), and the Conjugate Gradient (CG) algorithms - the last two belong to the famous Newton-Krylov Subspace category. We started with the simplest type - the SOR scheme. But higher divergence factor and run time error pose a serious problem so far as its applicability in our wave-guide modeling is concerned. So here we have studied also SD and CG schemes. Their performances are evaluated and compared in terms of CPU time for various grid sizes. Here CG scheme proves to be the most effective one showing least computational time, assuring convergence while producing similar simulation results. Corresponding surface and contour plots of the electric field profiles for GaAs and GeSi material systems determined by our scheme when compared to the 2nd order central difference scheme, show same qualitative behavior and so verify its acceptability and applicability as well.

Optik - International Journal for Light and Electron Optics, 2016

Abstract Semi conductor optical wave guides with well defined refractive index profile and geomet... more Abstract Semi conductor optical wave guides with well defined refractive index profile and geometric shapes which help to understand the propagation properties are widely used in the field of integrated optics. Accordingly rib waveguides are considered, as this structure allows the greatest versatility in device design in which the basic concept employed is its compositional changes in the vertical direction where the three regions of the rib structure are divided into zones with specific refractive indices. As for these types of structures no precise analytic solution is obtained, different numerical techniques have been implemented for their study in terms of their modal analysis. So an accurate higher order compact (HOC) finite difference method (FDM) in combination with conjugate gradient method (CGM) is used here for the investigation of refractive index profile of GaAs and GeSi rib waveguide structure to show their effect on transmission properties of the guided wave using Helmholtz wave equation. The difference in surface and contour plots of the polarized E-field solution clearly shows the material dependence of transmitted waves. We have also studied the variation of optical confinement factor with a number of parameters to understand the propagation properties appropriately as per the requirement of various guided wave optoelectronic devices.

Physical Review A, 1996

The nonlinear differential equation for the electron density in an arbitrary closed shell for a b... more The nonlinear differential equation for the electron density in an arbitrary closed shell for a bare Coulomb field as derived by Cooper [Phys. Rev. A 50, 1040 (1994)] is reduced to a Sturm-Liouville problem. Using supersymmetry inspired ladder-operator relations for the continuum Coulomb problem, the appropriate electron density is expressed exactly in the same way as the bound-state case.

The European Physical Journal D - Atomic, Molecular and Optical Physics, 1999

: A three-parameter correlated wave function for the helium ground state is used to study the s... more : A three-parameter correlated wave function for the helium ground state is used to study the scattering reaction , where Ps stands for positronium atom. An exact analytical expression is constructed for the first Born scattering amplitude for Ps formation from helium. Based on this numerical results are presented for both differential and total cross-sections. It is demonstrated that the