limited water resources, especially in iran, require most effective method of water use to avoid losses. one of the important parameters in irrigation is water distribution uniformity coefficient (cu) in sprinkler irrigation. cu in every irrigation depends on pressure heads (p), riser height (rh), distance between sprinklers on lateral pipes (sl), and the distance between lateral pipes (sm). th...

To judge about the performance of designed support system for tunnels, structural forces i.e. peak values of axial and shear forces and moments are critical parameters. So in this study, at first a complete database using finite element method was prepared. Then, a model of artificial neural network (ANN) using multi-layer perceptron was developed to estimate lining structural forces. Sensitivi...

The piano key weir (PKW) is a type of nonlinear control structure that can be used to increase unit discharge over linear overflow weir geometries, particularly when the weir footprint area is restricted To predict the outflow passing over a piano key weir, the discharge coefficient in the general equation of weir needs to be known. This paper presents the results of laboratory model testing of...

1. Introduction. The purpose of this article is to study long time existence for high dimensional quasilinear wave equations exterior to star-shaped obstacles. In particular, we seek to prove exterior domain analogs of the four dimensional results of [5] where the nonlinearity is permitted to depend on the solution not just its first and second derivatives. Previous proofs in exterior domains o...

System reliability optimization models considering uncertainty are reviewed and a new formulation is proposed to minimize the coefficient of variation of the system reliability estimate. The redundancy allocation problem can be described as selection of the components and system configuration to optimize some objective function(s) without violating system related constraints. In this paper, we ...

In this paper we consider the problem of estimating a coefficient of a strongly elliptic partial differential operator in stochastic parabolic equations. The coefficient is a bounded function of time. We compute the maximum likelihood estimate of the function on an approximating space (sieve) using a finite number of the spatial Fourier coefficients of the solution and establish conditions that...