in this work an analytical equation of state has been employed to calculate the pvt properties ofternary refrigerant mixtures. the theoretical eos is that of ihm, song and mason, which is based onstatistical-mechanical perturbation theory, and the two constants are enthalpy of vaporization δhvapand molar density ρnb, both at the normal boiling temperature. the following three temperaturedepende...

In this note, small amplitude free vibration of a double-beam system in presence of inner layer nonlinearity is investigated. The nonlinearity is due to inner layer material and is not related to large amplitude vibration. At first, frequencies of a double-beam system with linear inner layer are studied and categorized as synchronous and asynchronous frequencies. It is revealed that the inner l...

In this paper, a generalized mathematical model of spread of infectious disease as SIRS epidemic model is considered as a nonlinear system of differential equation. We prove that for positive initial conditions the resulting equivalence system has positive solution and under some hypothesis, this system with initial positive condition, has a positive $T$-periodic solution which is globally asym...

In this paper, we propose a method to approximate the solution of a linear Fredholm integro-differential equation by using the Chebyshev wavelet of the first kind as basis. For this purpose, we introduce the first Chebyshev operational matrix of integration. Chebyshev wavelet approximating method is then utilized to reduce the integro-differential equation to a system of algebraic equations. Il...

In this article the instability of single phase flow in a circular pipe from laminar to turbulence regime has been investigated. To this end, after finding boundary conditions and equation related to instability of flow in cylindrical coordination system, which is called eigenvalue Orr Sommerfeld equation, the solution method for these equation has been investigated. In this article Chebyshev p...

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...

the present work is the successful extension of an improved equation of state (eos) to refrigerant fluids. the objective is the prediction of isothermal and saturated liquid densities of refrigerants. two temperature-independent parameters appearing in the modified eos are closely related to critical point properties of refrigerant fluids. our results showed that, the proposed eos can predict w...

in this paper we study shadowing property for sequences of mappings on compact metric spaces, i.e. nonautonomous discrete dynamical systems. we investigate the relation of  weak contractions with shadowing and h-shadowing property.

background: the present study was performed to develop a scoring system for predicting cure status in patients with cutaneous leishmaniasis (cl). materials and methods: this study included 199 patients with cl from skin diseases and leishmaniasis research center (isfahan, iran). data were collected as longitudinal in each visit of patients. we applied ordinal logistic generalized estimating equ...