Volume 1, Number 1, 2022
Compact Difference Schemes Combined with Runge-Kutta Methods for Solving Unsteady Convection-Diffusion Problems
Abstract
The convection-diffusion equation is of primary importance in understanding transport phenom-ena within a physical system. However, the currently available methods for solving unsteady convection-diffusion problems are generally not able to offer excellent accuracy in both time and space variables. A procedure was given in detail to solve the one-dimensional unsteady
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The convection-diffusion equation is of primary importance in understanding transport phenom-ena within a physical system. However, the currently available methods for solving unsteady convection-diffusion problems are generally not able to offer excellent accuracy in both time and space variables. A procedure was given in detail to solve the one-dimensional unsteady convec-tion-diffusion equation through a combination of Runge-Kutta methods and compact difference schemes. The combination method has fourth-order accuracy in both time and space variables. Numerical experiments were conducted and the results were compared with those obtained by the Crank-Nicolson method in order to check the accuracy of the combination method. The anal-ysis results indicated that the combination method is numerically stable at low wave numbers and small CFL numbers. The combination method has higher accuracy than the Crank-Nicolson method.Full article
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Article
Charged Anisotropic Stellar Models with the MIT Bag Model Equation of State
Abstract
In this paper we present a new classes of solutions for the Einstein-Maxwell system of field equations in a spherically symmetric spacetime under the influence of an electric field considering the MIT bag model equation of state with a particular form the metric potential that depends on an adjustable parameter.
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In this paper we present a new classes of solutions for the Einstein-Maxwell system of field equations in a spherically symmetric spacetime under the influence of an electric field considering the MIT bag model equation of state with a particular form the metric potential that depends on an adjustable parameter. The obtained solutions can be written in terms of elementary functions, namely polynomials and algebraic functions. The obtained models satisfy all physical properties expected in a realistic star. The results of this research can be useful in the development and description of new models of compact structures.Full article
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Article
The Calculation of the Binding Energy of the Exciton Moving in a Two dimensional Semiconductor Quantum Well
Abstract
With respect to the exciton moving in the two-dimensional quantum well, the paper presents a scheme which can rigorously calculate out the binding energy of the exciton in the two-dimensional semiconductor quantum well by simply using the relation
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With respect to the exciton moving in the two-dimensional quantum well, the paper presents a scheme which can rigorously calculate out the binding energy of the exciton in the two-dimensional semiconductor quantum well by simply using the relation , which is much simpler than the complex calculation of Ref.[1-2]. Concerning the calculation result eq.(13), the paper discusses the results for two significant cases of <<and .Full article
Editorial
On Simultaneous Submission
Abstract
The aim of this note is to remind and explain that authors have an obligation to make sure their manuscript is based on original research, which means it is never before published. Intentionally submitting or re-submitting a manuscript for more than publication is considered a violation of publishing ethics.
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The aim of this note is to remind and explain that authors have an obligation to make sure their manuscript is based on original research, which means it is never before published. Intentionally submitting or re-submitting a manuscript for more than publication is considered a violation of publishing ethics.Full article
Editorial
ISSN: 2834-5479
DOI prefix: 10.31586/ujpr
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