in recent decades, attention to contamination propagation into soils and underground water has increased, which has led to a rise in the studies on soil contamination problems and methods of in-situ remediation. in this research, effective parameters on oil contamination propagation in soils and underground water have been investigated using fem in order to determine propagation patterns. the m...

open-channel junctions have a broad application in civil and environmental engineering. formation of a low-pressure zone with recirculating flow (high sedimentation) accompanied by a high-velocity zone (high erosion) is the most characteristic feature of flow in junctions. a large number of researches have been performed to study the complexity of the flow in junctions in open-channel flows. in...

ultra-short pulse is a promising technology for achieving ultra-high data rate transmission which is required to follow the increased demand of data transport over an optical communication system. therefore, the propagation of such type of pulses and the effects that it may suffer during its transmission through an optical waveguide has received a great deal of attention in the recent years. we...

In this article we have considered a non-standard finite difference method for the solution of second order  Fredholm integro differential equation type initial value problems. The non-standard finite difference method and the composite trapezoidal quadrature method is used to transform the Fredholm integro-differential equation into a system of equations. We have also developed a numerical met...

In this paper, we introduce the notions of C-numerical range and C-spectrum of matrix polynomials. Some algebraic and geometrical properties are investigated. We also study the relationship between the C-numerical range of a matrix polynomial and the joint C-numerical range of its coefficients.

in this paper, a numerical solution for a system of linear fredholm integro-differential equations by means of the sinc method is considered. this approximation reduces the system of integro-differential equations to an explicit system of algebraic equations. the exponential convergence rate $o(e^{-k sqrt{n}})$ of the method is proved. the analytical results are illustrated with numerical examp...

in this paper, an effective numerical method is introduced for the treatment of nonlinear two-dimensional volterra-fredholm integro-differential equations. here, we use the so-called two-dimensional block-pulse functions.first, the two-dimensional block-pulse operational matrix of integration and differentiation has been presented. then, by using this matrices, the nonlinear two-dimensional vol...

abstract. the main contribution of the current paper is to propose a new effective numerical method for solving the first-order linear matrix differential equations. properties of the legendre basis operational matrix of integration together with a collocation method are applied to reduce the problem to a coupled linear matrix equations. afterwards, an iterative algorithm is examined for solvin...

In this note we characterize polynomial numerical hulls of matrices $A in M_n$ such that$A^2$ is Hermitian. Also, we consider normal matrices $A in M_n$ whose $k^{th}$ power are semidefinite. For such matriceswe show that $V^k(A)=sigma(A)$.

Most of river engineering problems are complicated and need to be analyzed by three dimensional models of flow and sediment transport. Considering the fact that computers and numerical methods with great ability of flow and sediment transport simulation are developing quickly, using numerical modeling by engineers is inevitable. Nevertheless, before application, numerical models need to be veri...