many procedures suggest for reduction of responses of riser to vortex induced vibrations (viv). natural frequencies of marine risers is an important parameter that can affect the responses of riser to viv. change of riser properties such as top tension and bending stiffness can alter natural frequencies. in this study effects of riser specifications on the responses and fatigue damage of marine...

rectangular waveguide (wr) is one of the earliest types of transmission lines. rectangular waveguide can be produced by hot extrusion process. in this paper, the hot extrusion process of cuzn5 rectangular waveguide was investigated by finite element method (fem). in addition, genetic algorithm method (ga) was used to optimize the die geometry and process conditions to achieve the lowest magnitu...

drying is an important operational step in pistachio processing. there is a decrease in moisture content of pistachio nuts from 56-57% (d.b.) to 5-6% during the drying process. drying conditions affect the quality of dried pistachio nuts, therefore, this calls for an accurate description of the drying trend in the process. in this study finite element formulation and solution of diffusive moist...

buckle folds are common traps for hydrocarbon in several contractional provinces. buckle folds form where stratified sequences rest a top salt or some other utterly weak rock as a decollemet zone in units with high competency contrasts by a compressive stress which acted along the length of the rock layers. an important parameter affecting buckle folding of a competent zone above a mobile decol...

in this paper, finding dynamic load carrying capacity (dlcc) of flexible link manipulators in point to-point motion was formulated as an optimal control problem. the finite element method was employed for modelling and deriving the dynamic equations of the system. the study employed indirect solution of optimal control for system motion planning. due to offline nature of the method, many diffic...

the purpose of this study is to compare the results of different probabilistic methods such as the perturbation method, stochastic finite element method (sfem) and monte carlo method. these methods were used to study the convergence of direct approach for slope stability analysis and are developed for a linear soil behavior. in this study, two dimensional random fields are used and both the fir...

a two-dimensional (2d) single particle model for the copolymerization of propylene-ethylene with heterogeneous ziegler-natta catalyst is developed. the model accounts for the effects of the initial shape of the catalyst and carck/ pore patterns on the copolymer composition, polymerization rate and the average molecular weight properties. the spherical and oblate ellipsoidal shapes of catalyst p...

In this paper, a semi-analytical approach for the 1 eigenproblem of circular plates with multiple circular holes is 2 presented. Natural frequencies and modes are determined by 3 employing the null-field integral formulation in conjunction 4 with degenerate kernels, tensor rotation and Fourier series. In 5 the proposed approach, all kernel functions are expanded into 6 degenerate (separable) fo...

This paper examines efficient methods for the calculation of open circuit voltage distortion in salient pole synchronous generators with damper windings. It then proceeds to examine the role of damper bars in the level of distortion. The simplified finite element method employed is inclusive of eddy current effects, dynamic field current and full interaction of all MMF sources. It allows accura...