Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Three


Effect of Friction on the Dynamical Analysis of Three-Link Planar Robot Arm by Using Lagrange Approach

R.M. Hussein

Engineering and Technology Journal, 2017, Volume 35, Issue 6, Pages 587-592

The dynamic analysis of Three-Link planar robot arm and control system with (PID) are presented and investigated. The dynamic analysis is very important in the design and control of the robot. The difference between the actual dynamic analysis and ideal dynamic analysis is the presence of friction in the robot joints. In this work, the frictional effect in the joints of three-link planar robot is inserting in the dynamic equations and that makes the dynamic analysis is more reality and difficult. The mathematical model that represent the friction consist of two types of friction (Coulomb and viscous friction). A Lagrange method is used and applied to evaluate the generalized forces in the two cases (without and with the effect of friction). Control system with (PID) controller is presented with Simulink block set to evaluate and show the dynamic response of each link in two cases (without and with friction). MATLAB software is used for programing and simulation the equations. In addition, with that, error signals are presented and analyzed for each link. It is concluded from the results that the values of generalized forces in case of presence of friction are more about (12%) than the values of the forces in case of without friction and the behaviors of the dynamic response is linear in case of without friction while the behavior become (non-linear) by inserting the frictional effect in the robot joints. The results indicate that the effect of friction is very important and must be not neglected.

Optimal Design of Three-Phalanx Prosthesis Underactuated Fingers Using Genetic Algorithm

Sadeq H. Bakhy; Shaker S. Hassan; Somer M. Nacy; Alejandro Hernandez-Arieta; K. Dermitzakis

Engineering and Technology Journal, 2013, Volume 31, Issue 6, Pages 1045-1068

This research is interested to investigate the optimum design procedure for a finger driving mechanism to have a proper configuration of the finger for its utilization in hand prosthesis. To get this goal, a Genetic Algorithm (G.A) was used. Three criteria were selected to find the optimal solution. The most important of them was the percentage of the grasping stability. This criterion was evaluated as must type by using Kepner-tregos method. When the optimal solution was found, this one was modified to facilitate the fabrication of a prototype. The modifications consist of mostly rounding the parameters and uniforming the rollers dimensions. Those changes did not affect too much the forces characteristics. The prosthetic hand prototype was built of hard ABS (Acrylonitrile Butadiene Styrene) plastic using rapid prototyping. Testing results indicate that the proposed Genetic Algorithm gives reasonable -quality results in short computation time.

CFD Modeling and Gas Holdup Measurement in Three-Phase Slurry Bubble Column

Ali H. Jawad; Raheek I. Ibrahim; Amer A. AbdulRahman

Engineering and Technology Journal, 2009, Volume 27, Issue 16, Pages 3012-3022

Gas-Liquid-Solid system as slurry in a reactor have a wide range of applications in industry, a slurry reactor is a vessel containing the catalyst suspended in a liquid phase. In this study, we develop a CFD model to predict the gas holdup at different gas superficial velocities.
The experiments were done in a gas-liquid-solid slurry bubble column to find the gas holdup (eG). The experimental data showed a good agreement with CFD results. An empirical correlation has been developed to predict the gas holdup for three-phase slurry with a correlation co-efficient of 0.994; this correlation shows that the gas holdup predicted was in good agreement with experimental values.

Ethanol Bioproduction in Three-Phase Fluidized Bioreactors

Haiyam Mohammed A. Al-Raheem

Engineering and Technology Journal, 2009, Volume 27, Issue 12, Pages 2385-2397

In the last decade bioalcohol has become more and more important as an alternative
energy source and chemical feed stock. Bioethanol production has been proposed as a
gasoline enhancer to reduce greenhouse gases, gasoline imports, and to boost the economy.
Circulating fluidized beds (CFB) have been used in a variety of industrial processes due to
their distinct advantages of uniform temperature distribution, high gas-to- particle mass and
heat transfer rates and flexible operation.
The present study deals with the experimental analysis of the circulating fluidized bed
reactor, which is applied to the fermentation of glucose to ethanol. The study takes into
consideration the presence of three different phases; yeast (solid) which is continuously
fluidized by the liquid stream (glucose solution), and the gas bubbles which greatly enhance
mixing and the wake phase which follows tracks of the gas bubbles. The reactor
performance is analyzed as a function of major operating conditions, the yeast mass in the
reactor (30-150gm/l), the concentration of glucose in feed (10-150gm/l), reaction
temperature (15,25,30,36,37, and 40ºC) , and velocities of gas and liquid feeds (0.01-0.1m/s).
The results indicate that high glucose conversions can be obtained at high gas velocities, low
liquid velocities, high yeast concentration, and an optimum operating temperature of 36oC.

Numerical Investigation intoVelocity and Temperature Fields Over Smooth and Rough Ducts for Several Types of Turbulators

Sabah Tarik Ahmed; Waheed S. Mohammed; Laith J.H

Engineering and Technology Journal, 2007, Volume 25, Issue 10, Pages 1110-1127

Numerical study on a laminar and turbulent fluid flow and
temperature distribution in a rectangular duct with six types of vortex
generators has been carried out. A modified version of ESCEAT threedimension
code has been used to solve Navier-Stokes and energy equations.
The effect of vortex generator type, geometrical configuration, and
dimensions on flow and temperature in different planes has been presented.
The purpose of the present investigation is to highlight the complex threedimensional
interaction of the vortices generated by wings and other vortex
generators to understand how such vortices configurations structure the
velocity and temperature fields. Experiment in terms of velocities and
temperatures vectors and contours were performed on 6 configurations,
which experiments are (fin, fence, rib, wing-type, rectangular-type, and
winglet-type) vortex generators The results show good agreement with
published data.