نشریه شریف
پیاپی 48 (خرداد و تیر 1388)

In this paper a method based Nshtyaby way acoustic wave propagation in gas pipelines is proposed. Bdynmnzvr, acoustic sound waves of energy balance as a tool for tracking the occurrence of leaks, leak location estimates, as well as Dubai, the amount used. Knowing the amount of energy input to the tube and the amount of acoustic reflection, and password from the leakage of energy absorbed and created changes in the amplitude, location and amount of leakage is approximated. Equations governing the acoustic field in spite of leakage Lvlhyy written using the finite difference method is solved. Much reflection, and passes acoustic energy absorption due to leakage Bhaza’ wave frequency changes as well as spill size is shown. Effect size and various places on how to leak acoustic pressure wave propagation is investigated.

Behavior of concrete structures under quasi-static and dynamic loading conditions, are different. In this study the dynamic behavior of concrete at high rates Krnshhay, experimental basis using explosives of loading, and the results are compared with theoretical data. Explosive in the crimes and the different heights of the concrete form of the Persian month Tir Blvkhhay Sadhand are placed. Involvement with the static properties of concrete and pressure caused the explosion, increased load-bearing capacity obtained in dynamic mode comes. These tests measure the damage created cracks in the tensile region is considered tir. The results suggest increased dynamic factor (load-bearing capacity) rate of between 4.5 to 6 Bhaza’ Krnshhay 66s-1 80s-1 is up. These results with theoretical results and previous work conducted conforms. In the end, using Minitab statistical software using the method of experimental design (DOE), a quasi experimental mathematical model for concrete behavior under explosive load is introduced.

One of the major components of absorbent absorption chillers and chiller efficiency is the role Bhszayy. In this article how numerical modeling of water vapor in the process of absorbing water soluble lithium bromide vertical screen, under the terms of 5 to 150 Reynolds, is presented. This hypothesis using boundary layer equations for heat transfer, mass and momentum, as well as implicit finite difference method for solving equations has been extracted. Properties affected by changes in temperature and solution concentration, and change in film thickness due to absorption is considered. Provided the model now offers profiles of temperature, concentration, solution properties and absorption mass flux and heat transfer coefficients and mass is. Solved in terms of desired body {8} In order to compare with experimental results has been done.

In this study Shshdrjh freedom robot with active Shshpayy Shshdrjh release is designed to turn the legs are Chharmylhyy mechanism. This mechanism has led each of the robot legs instead of rotational motion, reciprocating motion, such as insect legs Shshpa do. Although each leg has a degree of freedom, compared to non Mfslbndyhay its behavior to move the legs like an insect Shshpa is created that this Brtryha and funds of the robot with other robots distinction Shshpay Shshdrjh freedom ever made. In this study first movement features an insect like cockroach Shshpa and then paid to the robot leg design, review Kinematics robot, static stability, extraction, and the dynamic equations to determine the input moments per foot of active links is acting. Finally Amalshdh torque equation about the stimuli is obtained.

In this paper anisotropic Reynolds stress turbulence model (RSM) in the computational code EPISO actions and results kvarepsilon isotropic model for single phase and diphasic states compared to that have good coordination. The impact of gas-phase turbulent flow inside the engine Ghyrhmsangrd the shape and appearance parameters of the spray, during infiltration, evaporation rates and distribution of fuel vapor with the RSM model has been studied. RSM model results show that during the spray penetration into the lower field of the model prediction seems kvarepsilon. The evaporation rate of spray model RSM Ghyrhmsangrd the combustion chamber more kvarepsilon isotropic model predicts. In fact, shorter length of influence predicted by the RSM model, rooted in higher evaporation rates in this model is.

In this study using the finite element method, pieces of geometry effects on calibration coefficients have been Mvrdbrrsy Drrvsh drilling. Bdynmnzvr Astvanhyy process simulation for parts with different diameters and then took a flat page, and calibration coefficients are determined for different Hnds·hhay. In analysis, the hole diameter and geometry Shakhhyy Krnshsnj constant, and only piece of geometry has changed. Analysis for each segment by changing the depth of the hole has been done in eight stages. Compare simulation results for the flat page and the values in the standard error represents approximately 2.8 percent. Also, comparing the results for surfaces with flat curves in various drilling depths, the differences between 0.6 to 6.2 percent differently has shown.

In this study, screw connection strings drilling tools in drilling vertical wells most at risk of failure of the other members are using axial symmetric elements software ANSYS, finite element method and model are. For modeling contact between the surfaces of the contact elements and phenomena of interest constraint equations. Tensile and compressive axial forces, internal and external pressures resulting from the drilling fluid, pipe, torque from the engine at the top Amalshdh wells, and bending moments resulting from heavy pipes buckling in drilling wells down into the main loads that are Bhmdl. API standards in order to improve the fatigue behavior of these connections as well as some Pyshbar it applies. Model under tensile loading, compression, pure Pyshbar has been a combination of them. Determine the location and maximum stress concentration factor in pin (pin) and box (box), the effect on the amount of exercise Pyshbar stress concentration factor, as well as its impact on the critical indentation load and subsequently fatigue life including the things in this article It has been discussed. Finally, the debate about the convergence of stress levels in response surfaces are presented.