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2,276 results on '"NISAR, KOTTAKKARAN SOOPPY"'

1. Unraveling the mysteries of wormhole formation in Rastall-Rainbow gravity: A comprehensive study using the embedding approach

Author

Errehymy, Abdelghani, Banerjee, Ayan, Donmez, Orhan, Daoud, Mohammed, Nisar, Kottakkaran Sooppy, and Abdel-Aty, Abdel-Haleem

Subjects
General Relativity and Quantum Cosmology
Abstract

The present work looks for the possible existence of static and spherically symmetric wormhole geometries in Rastall-Rainbow gravity. Since, the Rastall-Rainbow gravity model has been constructed with the combination of Rastall theory and the gravity's rainbow formalism. Taking advantage of the Karmarkar condition for embedding class one metrics, we solve the modified field equations analytically that describe wormholes for specific choice of redshift function. For specific parameter ranges, the solution represents a traversable wormhole that exhibits the violation of null energy condition and consequently the weak energy condition also. Furthermore, we focus on the wormhole stability via adiabatic sound velocity analysis. This model establishes a strong connection between two model parameters, namely, the Rastall parameters and the Rainbow functions, and how it affects the wormhole solution., Comment: Accepted for publication in Gen. Relativ. Gravit., 17 pages, 17 figures

Published
2024

3. Vieta-Lucas Wavelet based schemes for the numerical solution of the singular models

Author

Aeri, Shivani, Kumar, Rakesh, Baleanu, Dumitru, and Nisar, Kottakkaran Sooppy

Subjects
Mathematics - Numerical Analysis
Abstract

In this paper, numerical methods based on Vieta-Lucas wavelets are proposed for solving a class of singular differential equations. The operational matrix of the derivative for Vieta-Lucas wavelets is derived. It is employed to reduce the differential equations into the system of algebraic equations by applying the ideas of the collocation scheme, Tau scheme, and Galerkin scheme respectively. Furthermore, the convergence analysis and error estimates for Vieta-Lucas wavelets are performed. In the numerical section, the comparative analysis is presented among the different versions of the proposed Vieta-Lucas wavelet methods, and the accuracy of the approaches is evaluated by computing the errors and comparing them to the existing findings., Comment: 23 pages, 4 figures, 2 Tables

Published
2023

10. Comparative study of copper nanoparticles over radially stretching sheet with water and silicone oil

Author

Hayat Umer, Shaiq Shakil, Nisar Kottakkaran Sooppy, Shahzad Azeem, Farooq Aamir, Kamran Muhammad, and Shah Nehad Ali

Subjects
copper nanoparticles, silicone oil, stretching sheet, shape factor, slip parameter, Technology, Chemical technology, TP1-1185, Physical and theoretical chemistry, QD450-801
Abstract

Copper nanoparticles are widely used in many sectors and research endeavors owing to their unique properties, including a large surface area, catalytic capabilities, and high thermal and electrical conductivity. The selection of the base fluid for copper nanoparticles should be contingent upon the anticipated application requirements since various fluids exhibit distinct characteristics that could potentially impact the mobility of the nanoparticles. The present investigation analyzes heat transfer phenomena occurring across a radially stretched surface. The research explores the effects of different states of Cu nanoparticles when combined with base fluids, such as water and silicone oil, on the heat transfer process. The momentum and energy equations are transformed into nonlinear ordinary differential equations by applying the similarity transformation. The boundary value problem-fourth-order (BVP4C) method numerically solves the governing ordinary differential equation for the modeled problem. In addition, the influence of various factors such as the slip parameter, solid volume fraction, Eckert number, Prandtl number, and unsteadiness parameter are examined. It has been discovered that blade-shaped nanoparticles transfer heat as quickly as possible via silicone oil and water. However, for platelet-shaped nanoparticles, a minimum heat transfer rate has been noted. The maximum skin friction coefficient is observed in platelet-shaped nanoparticles, while blade-shaped nanoparticles have the lowest skin friction coefficient.

Published
2024
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11. Some Specific Wormhole Solutions in Extended $f(R,G,T)$ Gravity

Author

Ilyas, M., Athar, A. R., Khan, Fawad, Ghafoor, Nasreen, Alrebdi, Haifa I., Nisar, Kottakkaran Sooppy, and Abdel-Aty, Abdel-Haleem

Subjects
General Relativity and Quantum Cosmology
Abstract

This research work provides an exhaustive investigation of the viability of different coupled wormhole (WH) geometries with the relativistic matter configurations in the $f(R,G,T)$ extended gravity framework. We consider a specific model in the context of $f(R,G,T)$-gravity for this purpose. Also, we assume a static spherically symmetric space-time geometry and a unique distribution of matter with a set of shape functions ($\beta(r)$) for analyzing different energy conditions (ECs). In addition to this, we examined WH-models in the equilibrium scenario by employing anisotropic fluid. The corresponding results are obtained using numerical methods and then presented using different plots. In this case, $f(R,G,T)$ gravity generates additional curvature quantities, which can be thought of as gravitational objects that maintain irregular WH-situations. Based on our findings, we conclude that in the absence of exotic matter, WH can exist in some specific regions of the parametric space using modified gravity model as, $f(R,G,T) = R +\alpha R^2+\beta G^n+\gamma G\ln(G)+\lambda T$., Comment: Modified, 31 pages, 11 figures

Published
2022

13. A comprehensive review on fractional-order optimal control problem and its solution

Author

Abd-Elmonem Assmaa, Banerjee Ramashis, Ahmad Shabir, Jamshed Wasim, Nisar Kottakkaran Sooppy, Eid Mohamed R., Ibrahim Rabha W., and El Din Sayed M.

Subjects
fractional order optimal control problem, two-point boundary value problem, fractional order differential equation, fractional delay differential equation, numerical methods, 26a33, 35g15, Mathematics, QA1-939
Abstract

This article presents a comprehensive literature survey on fractional-order optimal control problems. Fractional-order differential equation is extensively used nowadays to model real-world systems accurately, which exhibit fractal dimensions, memory effects, as well as chaotic behaviour. These versatile features attract engineers to concentrate more on this, and it is widely used in the broad domain of science and technology. The mentioned numerical tools take the necessary optimal conditions into account, which makes it a two-point boundary value problem of non-integer order. In this review article, some numerical approaches for the approximation have been stated for obtaining the solution to fractional optimal control problems (FOCPs). Here, few numerical approaches including Grunwald-Letnikov approximation, Adams type predictor-corrector method, generalized Euler’s method, Caputo-Fabrizio method Bernoulli and Legendre polynomials method, Legendre operational method, and Ritz’s and Jacobi’s method are treated as an advanced method to obtain the solution of FOCP. Fractional delayed optimal control is selected for our investigation. It refers to a type of control problem where the control action is delayed by a fractional amount of time. In other words, the control input at a given time depends not only on the current state of the system but also on its past state at fractional times. The fractional delayed optimal control problem is formulated as an optimization problem that seeks to minimize a cost function subject to a set of constraints that represent the dynamics of the system and the fractional delay in the control input. The solution to this problem typically involves the use of fractional polynomials types, i.e. Chebyshev and Bassel polynomials.

Published
2023
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