Browsing by Author "Vahid, K. Zarghami"

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Citation Count: Jajarmi, A...et al. (2021). "A new and general fractional Lagrangian approach: A capacitor microphone case", Results in Physics, Vol. 31.
A new and general fractional Lagrangian approach: A capacitor microphone case
(2021) Jajarmi, A.; Baleanu, Dumitru; Vahid, K. Zarghami; Pirouz, H. Mohammadi; Asad, J. H.; 56389
In this study, a new and general fractional formulation is presented to investigate the complex behaviors of a capacitor microphone dynamical system. Initially, for both displacement and electrical charge, the classical Euler-Lagrange equations are constructed by using the classical Lagrangian approach. Expanding this classical scheme in a general fractional framework provides the new fractional Euler-Lagrange equations in which non-integer order derivatives involve a general function as their kernel. Applying an appropriate matrix approximation technique changes the latter fractional formulation into a nonlinear algebraic system. Finally, the derived system is solved numerically with a discussion on its dynamical behaviors. According to the obtained results, various features of the capacitor microphone under study are discovered due to the flexibility in choosing the kernel, unlike the previous mathematical formalism.
A new comparative study on the general fractional model of COVID-19 with isolation and quarantine effects
(2022) Baleanu, Dumitru; Abadi, M. Hassan; Jajarmi, A.; Vahid, K. Zarghami; Nieto, J. J.; 56389
A generalized version of fractional models is introduced for the COVID-19 pandemic, including the effects of isolation and quarantine. First, the general structure of fractional derivatives and integrals is discussed; then the generalized fractional model is defined from which the stability results are derived. Meanwhile, a set of real clinical observations from China is considered to determine the parameters and compute the basic reproduction number, i.e., R-0 approximate to 6.6361. Additionally, an efficient numerical technique is applied to simulate the new model and provide the associated numerical results. Based on these simulations, some figures and tables are presented, and the data of reported cases from China are compared with the numerical findings in both classical and fractional frameworks. Our comparative study indicates that a particular case of general fractional formula provides a better fit to the real data compared to the other classical and fractional models. There are also some other key parameters to be examined that show the health of society when they come to eliminate the disease. (C) 2021 THE AUTHORS. Published by Elsevier BV on behalf of Faculty of Engineering, Alexandria University.