Yazar "Rizwan, Muhammad" seçeneğine göre listele

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    Öğe
    A mathematical analysis and simulation for Zika virus model with time fractional derivative
    (Wiley, 2020) Farman, Muhammad; Ahmad, Aqeel; Akgul, Ali; Saleem, Muhammad Umer; Rizwan, Muhammad; Ahmad, Muhammad Ozair
    Zika is a flavivirus that is transmitted to humans either through the bites of infected Aedes mosquitoes or through sexual transmission. Zika has been associated with congenital anomalies, like microcephalus. We developed and analyzed the fractional-order Zika virus model in this paper, considering the vector transmission route with human influence. The model consists of four compartments: susceptible individuals arex(1)(t), infected individuals arex(2)(t),x(3)(t)shows susceptible mosquitos, andx(4)(t)shows the infected mosquitos. The fractional parameter is used to develop the system of complex nonlinear differential equations by using Caputo and Atangana-Baleanu derivative. The stability analysis as well as qualitative analysis of the fractional-order model has been made and verify the non-negative unique solution. Finally, numerical simulations of the model with Caputo and Atangana Baleanu are discussed to present the graphical results for different fractional-order values as well as for the classical model. A comparison has been made to check the accuracy and effectiveness of the developed technique for our obtained results. This investigative research leads to the latest information sector included in the evolution of the Zika virus with the application of fractional analysis in population dynamics.
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    Öğe
    Effect of Sc and Zn doping on structure and electro-optical behavior in c-BiAlO3: A DFT trial
    (Elsevier Sci Ltd, 2022) Rizwan, Muhammad; Farman, Muhammad; Akgul, Ali; Ayub, Asma; Usman, Zahid
    Density Functional Theory (DFT) is an attractive route to search for new substitute lead free perovskite materials for linear and non-linear optics, with superior properties similar to PZT materials. We consider environment friendly facile c-BiAlO3 piezoelectric material, where Bi is substituted by transition metals (Sc, Zn). The effect of these dopant on the structural, electronic and optical properties of c-BiAlO3 are investigated by using generalized gradient approximation and ultrasoft pseudopotential method as implemented in CASTEP. Structural properties experience reciprocal effect on lattice constant as a function of ionic size of Impurities. In addition, a transition of indirect band gap of c-BiAlO3 to the direct one is obtained after TM impurity substitution. The optical properties such as absorption, energy loss, refractive index, dielectric function, function are computed for the energy range of 30eV. The static refractive index for pure and TM-doped obtained are 2.87, 2.99 and 3.5 respectively. Up-surges in static dielectric constants are also sighted, predicting a shift from semiconducting to metallic behavior after TM doping in c-BiAlO3. TM-doping has also boosted the absorption spectra response and reflectivity in the UV-region. Sc and Zn-doped c-BiAlO3 can be considered as potential materials in photovoltaic application.
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    Öğe
    Role of Zn in modification of electronic and optical properties of c-SrZrO3: a computational insight
    (Iop Publishing Ltd, 2020) Rizwan, Muhammad; Anam, S.; Farman, Muhammad; Akgul, Ali; Uzma, M.
    In this article, a DFT study is carried out to explore the electronic, structural and optical properties of SrZrO3(SZO). Zn is doped at Sr site in minimum quantity to explore the minimal effect of Zn on electronic behaviour and its impact on other properties. For investigation of these properties, Ultrasoft pseudopotentials (USP) and Generalized Gradient Approximation suggested by Perdew, Burke, and Ernzerhof (GGA-PBE) functional is executed. The inclusion of Zn at Sr site in SZO affects the electronic and optical properties significantly. Band gap was expressively reduced from 3.315 eV to 2.618 eV which has direct impact with interacting energies. The nature of band gap for both intrinsic and doped systems remain indirect which means Zn inclusion did not affect the nature of band gap. The change in electronic properties due to addition of impurity leads towards change in optical properties. All the optical properties including complex dielectric function, absorption spectra, reflection coefficient, refractive index and extinction coefficient were calculated. The results showed a clear red shift in the absorption spectra along with peak shifting from 2.98 eV to 0.63 eV and the refractive index obtained for pure material is 2.13 which then altered to 2.45 due to doping. Doping of zinc in SZO significantly alter the electronic and optical properties and thus making it a valuable asset for optoelectronic devices.