Detailed description of the heterogeneity of oil/gas reservoirs is needed to make performance predictions of oil/gas recovery. However, only limited measurements at a few locations are usually available. This combination of significant spatial heterogeneity with incomplete information about it leads to uncertainty about the values of reservoir properties and thus, to uncertainty in estimates of...

Partially Encased Composite (PEC) column is one of the recent achievements in the field of composite columns. This paper presents a combined experimental and theoretical study on the mechanical performances of six octagonal PEC columns subjected to axial compressive and bending moment loading. The major different between them was the concrete reinforcement details. The parameters studied in the...

‎in this paper‎, ‎we present a new modification of chebyshev-halley‎ ‎method‎, ‎free from second derivatives‎, ‎to solve nonlinear equations‎. ‎the convergence analysis shows that our modification is third-order‎ ‎convergent‎. ‎every iteration of this method requires one function and‎ ‎two first derivative evaluations‎. ‎so‎, ‎its efficiency index is‎ ‎$3^{1/3}=1.442$ that is better than that o...

‎the main purpose of this paper is to study the numerical solution of nonlinear volterra integral equations with constant delays, based on the multistep collocation method. these methods for approximating the solution in each subinterval are obtained by fixed number of previous steps and fixed number of collocation points in current and next subintervals. also, we analyze the convergence of the...

We examine whether a causal interpretation can be given to the function identified by the conditional moment restriction (CMR). It is shown that in a general nonseparable triangular system the CMR does not identify the average structural function (ASF) nor any other structural object. This implies that the CMR identifies a causal relation only if the model is structurally separable in observabl...

In an earlier publication, the authors reported the successful solution of the Fokker-Planck equation by the finite element method for a class of second order systems subjected to both additive and multiplicative white noise excitations, giving a complete picture of the evolution of the transition probability density functions of those systems. More recently, these solutions have been used to d...

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Previous epidemiological studies on SIS model have only considered the dynamic evolution of the mean value and the variance of the infected individuals. In this paper, through cumulant neglection, we use the dynamic equations of all the moments of infected individuals to develop a recursive method to compute the equilibria manifold of the moment closure ODE's. Specifically, we use the stable eq...

The radiative transfer equation describes the propagation of radiation through a material medium. While it provides a highly accurate description of the radiation field, the large phase space on which the equation is defined makes it numerically challenging. As a consequence, significant effort has gone into the development of accurate approximation methods. Recently, an extended quadrature met...

In the Langevin or Ornstein-Uhlenbeck approach to diffusion, stochastic increments are applied to the velocity rather than to the space variable. The density of this process satisfies a linear partial differential equation of the general form of a transport equation which is hyperbolic with respect to the space variable but parabolic with respect to the velocity variable, the Klein-Kramers or s...