eng
Materials and Energy Research Center
International Journal of Engineering
1025-2495
1735-9244
1995-05-01
8
2
1
61
71121
Computer Simulation of Ammonia Cold Shot Converter
E. Esmailzadeh
esmailzadeh@sharif.edu
1
D. Mowia
hasnomail@ije.ir
2
J. Fathi Kalajahi
fathi@shirazu.ac.ir
3
Mechanical Engineering, Sharif University of Technology
Chemical & Petroleum Engineering, Shiraz University
Chemical & Petroleum Engineering, Shiraz University
A mathematical model is developed and tested with plant data for the ammonia cold shot converter of Razi Petrochemical Complex. The model is based on a material and energy balance in a differential element of beds and is subjected to the assumptions of uniform distribution of temperature and composition through a general cross section and negligible mass and heat transfer in axial direction. The governing differential equations are solved by Runge-Kutta of fourth order to obtain temperature and concentration profiles through the reactor. The agreement between calculated temperature and composition with plant data confirms the validity of the developed model.
https://www.ije.ir/article_71121_31d0879fc71c3e9913d7ddbeadf8d7fe.pdf
Computer Simulation
mathematical model
Ammonia Converter
Ammonia Cold Shot Converter
Razi Petro Chemical Complex
eng
Materials and Energy Research Center
International Journal of Engineering
1025-2495
1735-9244
1995-05-01
8
2
71
84
71122
Tests to Determine the Joint Stiffness and Resisting Moment Capacity of Joints in Timber-Framed Houses
F. Nateghi
nateghi@iiees.ac.ir
1
structure, IIEES
Wind and earthquake disasters in the world often cause billions of dollars of damage to buildings, most of which is to non-engineered buildings-especially homes. Wood-frame homes use connectors which exhibit partial rotational rigidity at the member ends, making analytical solutions difficult. This is due to the lack of information about the complex behavior of the connections used in this type of buildings, and the lack of a methodology to analyze light-timber frame buildings with flexible joints. In order to address the problem, tests were carried out to determine the moment rotation characteristics of wood joints made of conventional and mechanical fasteners. During testing, it was discovered that rotational stiffness of timber connections is a function of the axial load as well as the shear load. Comparison of ordinary timber connections with metal connectors were made. Resisting moment capacity of joints with different connectors were also determined. This paper presents a new method of testing for joint stiffness and the experimental results obtained during testing for stud-to-bottom-plate, rafter-to-ridge-board, and top-plate-to-rafter connections using different connectors.
https://www.ije.ir/article_71122_138ea1c02f07e061ac3c4db442c9343d.pdf
Timber
Joints
connections
Moment
Resisting Capacity Tests
Rotational Stiffness
eng
Materials and Energy Research Center
International Journal of Engineering
1025-2495
1735-9244
1995-05-01
8
2
85
94
71123
Investigation of Melting by Molecular Dynamics Simulation
H. Akbarzadeh
akbarzad@cc.iut.ac.ir
1
S. Mohammad Amini
hasnomail@ije.ir
2
Physics, Isfahan University of Technology
Physics, Isfahan University of Technology
The melting of a 64 ion microcrystal of KCI was studied by means of a molecular dynamics computer simulation. We used a central pair interaction with an inverse power law repulsion. The thermodynamics, kinetic and structural properties such as melting temperature, latent heat, mean square displacement, diffusion constant, radial distribution function and bond angle distribution are calculated. The simulation indicated that the melting temperature of the microcrystal is lower than the experimental value of the bulk, which is consistent with the Gibbs-Thompson relation. It is shown that all the features of the melting transition which are observed in a bulk system are also exhibited by such a small microcrystal. The simulation is programmed in FORTRAN and run on a PC.
https://www.ije.ir/article_71123_4c93cee29e829b54579e940baffedeaf.pdf
Molecular Dynamics
Molecular Dynamic Simulation
Melting
Microcrystal
Ionic Salts
eng
Materials and Energy Research Center
International Journal of Engineering
1025-2495
1735-9244
1995-05-01
8
2
95
106
71124
Stress Concentration Factors in Spherical Vessels with Single Oblique Nozzle
K. Naderan
hasnomail@ije.ir
1
, Shahid Chamran University of Ahvaz
Finite element method is employed to analyze the spherical vessel intersected by an oblique cylindrical nozzle. In this survey the stress and strain distributions on acute and obtuse sides of the connection under internal pressure are studied widely although axial and moment loadings on the nozzle are also studied briefly. Stress concentration factors for a wide range of geometrical ratios in term of membrane stress in the sphere are calculated and presented. Variation of these factors with angle of obliquity of the branch is also investigated. The results are compared with measured quantities and with those mentioned in other references. It is assumed that the definition of thin shell is valid for both vessel and nozzle simultaneously and that the corners are sharp without any reinforcement. ABAQUS computer program is used in this survey.
https://www.ije.ir/article_71124_94ae6e8ef3bc25b82321b2012b5c1419.pdf
ABAQUS
Axial load
Bending Moment
Cylindrical
Equivalent Radius
Finite element method
Membrane
Non
radial
Nozzle
Oblique
Spherical
Thin Shell
Vessel
eng
Materials and Energy Research Center
International Journal of Engineering
1025-2495
1735-9244
1995-05-01
8
2
107
112
71125
Stress Analysis of the Human Ligamentous Lumber Spine-From Computer-Assisted Tomography to Finite Element Analysis
C. Breau
hasnomail@ije.ir
1
Mechanical Engineering, Ecole Polytechnique Fédérale de Lausanne
Detailed investigation on biomechanics of a complex structure such as the human lumbar spine requires the use of advanced computer-based technique for both the geometrical reconstruction and the stress analysis. In the present study, the computer-assisted tomography (CAT) and finite element method (FEM) are merged to perform detailed three dimensional nonlinear analysis of the human ligamentous lumbar spine. The details of the development of a three dimensional model of the lumbar spine using CAT images are initially described. Then the predicted nonlinear response of the system subjected to axial compression force is presented. The stress analysis is performed using a finite element code developed by Shirazi-Adl.
https://www.ije.ir/article_71125_1a2d0b7e5fb583fbe7431f6167eed9b3.pdf
Spinal Column
Stress analysis
Geometrical Reconstruction
Finite elements
Stability
eng
Materials and Energy Research Center
International Journal of Engineering
1025-2495
1735-9244
1995-05-01
8
2
113
120
71126
Robot Motion Vision Part II: Implementation
M.A. Taalebinezhaad
hasnomail@ije.ir
1
MIT Artificial Intelligence Laboratory, University of Cambridge
The idea of Fixation introduced a direct method for general recovery of shape and motion from images without using either feature correspondence or optical flow [1,2]. There are some parameters which have important effects on the performance of fixation method. However, the theory of fixation does not say anything about the autonomous and correct choice of those parameters. This paper presents the effect of those parameters on the experimental results of implementing some of the fixation algorithms on real images where the motion is a combination of translation and rotation. The results show that important motion components can be estimated accurately if the right parameters are used. Some of the critical issues involved in the implementation of autonomous robot motion vision are also discussed. Among these are the criteria for autonomously choosing an optimum size for the fixation patch, and appropriate choice of the fixation point location. Finally, a calibration method is described for precisely determining the location of real rotation axis in imaging systems.
https://www.ije.ir/article_71126_cd13bab2d720c765140a80e8d50156f7.pdf
Active Vision
computer vision
Feature Correspondence
Fixation
Motion Vision
Optical Flow
Pixel Shifting
Robot Vision