2024-03-29T15:15:24Z
https://www.ije.ir/?_action=export&rf=summon&issue=11416
International Journal of Engineering
IJE
1025-2495
1025-2495
1989
2
3
Polymer Impregnation of Concrete by Methyl Methacrylate and its Effects on Mechanical Properties and Corrosion of Steel in Concrete
R.
Dehghanian
Freezing and thawing resulting from the ingression of water into concrete causes cracking or spalling. Corrosive ions such as chloride or sulfate penetrate the concrete surface and eventually reach the reinforcing steel. This causes the steel to corrode. Because of the high maintenance and replacement costs, responsible officials should be increasingly concerned about the growing number of prematurely deteriorated concrete structures. One of the practical methods for reducing the high cost of repair is partial impregnation of concrete by polymers. In this paper, partial impregnation of concrete by methyl methacrylate for protection against deterioration of concrete is evaluated. Parameters such as the monomer system, drying time, drying temperature, soaking time, curing time and temperature are evaluated. All these parameters affect the economics of polymer impregnation of concrete. The results of this study show that corrosion of steel in the polymer impregnated concrete is lower than non- impregnated concrete. In addition, the mechanical properties of polymer impregnated concrete in comparison to concrete without polymer are improved.
1989
11
01
78
83
https://www.ije.ir/article_71002_bafc6344c8d75dd7efcf9c094bc7baf7.pdf
International Journal of Engineering
IJE
1025-2495
1025-2495
1989
2
3
Sucrose Inversion by Saccharomyces Yeast Cells Immobilized on to Corn Grits
Iran
Alemzadeh
Sucrose hydrolysis was carried Out by Saccharomyces strains. The effective rate of reaction was examined experimentally for 5 different Saccharomyces strains. Two Strains of Schizosaccharomyces and Saccharomyces Carlsbergensis showed the best invertase activity. These two strains showed Michaelien Kinetics in the sucrose concentration up to 0.2 M and inhibitory effect in the concentration beyond 0.2 M. These two strains were immobilized on to corn - grits by an adsorption technique. Immobilization of Saccharomyces carlsbergensison to corn - grits by adsorption was found to obey a first order reaction. Sucrose hydrolysis was studied in a continuously immobilized cell reactor.
1989
11
01
84
87
https://www.ije.ir/article_71003_8138a97e303d10bf39dbce4514122c40.pdf
International Journal of Engineering
IJE
1025-2495
1025-2495
1989
2
3
Rural Road Traffic Accidents in Iran
E.
Ayati
An up-to-date review of rural road accident statistics for Iran is presented The review considers sources of accident statistics in Iran and the means by which they are collected. The statistics are considered in relation to accident causal and risk factors. A comparison is made with statistics available for other countries at a similar stage of development and countries with highly developed economies. The statistics for Iran are presented by province to demonstrate within-country variations in statistics due to economic development, population density and other socio- economic variables.
1989
11
01
88
97
https://www.ije.ir/article_71004_8138a97e303d10bf39dbce4514122c40.pdf
International Journal of Engineering
IJE
1025-2495
1025-2495
1989
2
3
The Cost of Road Accidents in Iran
E.
Ayati
This paper gives an up-to-date estimate of the costs of road accidents in Iran. Conventional methods of estimating costs are considered together with special factors which apply to Iran. An attempt is made to quantify direct and indirect costs of accidents, including considerations relating to the exercise of Shar'ia law. The overall results show that road accidents account for between 1.4 and 1.8 percent of the Gross National Product.
1989
11
01
98
103
https://www.ije.ir/article_71005_1bb942b2cff242e349e3a9723136e130.pdf
International Journal of Engineering
IJE
1025-2495
1025-2495
1989
2
3
Lightning Protection of Ehv Substations in Iran
B.
Vahidi
M.
Abedi
Extra high voltage (EHV) substations are extremely vulnerable to the hazard of lightning strokes therefore, the shielding of these substations with a highly reliable protective scheme (shield wires) is an essential undertaking. In this paper an attempt is made to clarify the design procedure for shielding EHV substations against lightning with special reference to Iran.
1989
11
01
104
111
https://www.ije.ir/article_71006_7134834e376e4ed4343a62965f00f1cd.pdf
International Journal of Engineering
IJE
1025-2495
1025-2495
1989
2
3
Planning Robot Motion in a 2-D Region with Unknown Obstacles
C.
Lucas
The purpose of this paper is to present several algorithms for planning the motion of a robot in a two-dimensional region having obstacles whose shapes and locations are unknown. The convergence and efficiency of the algorithms are discussed and upper bounds for the lengths of paths generated by the different algorithms are derived and compared.
1989
11
01
112
117
https://www.ije.ir/article_71007_a2c381ed4bb08b006ecb748580f8f215.pdf
International Journal of Engineering
IJE
1025-2495
1025-2495
1989
2
3
A Parametric Cathment Erosion Model
N.
Samani
The structural framework for a parametric catchment erosion model is proposed. A parameter optimization technique that provides a rational basis for the calibration of the model is developed. The adequacy of the model in representing a natural catchment is investigated.
1989
11
01
118
127
https://www.ije.ir/article_71008_23bb165a94e91f6a740d3328dcd5c70c.pdf
International Journal of Engineering
IJE
1025-2495
1025-2495
1989
2
3
Improvement of Collapsibility of Sodium Silicate Bonded Cores for Aluminium Casting
J.
Hedjazi
This paper examines the compressive strength of sodium silicate bonded cores for aluminum casting with different additives. Various materials are used as additives among which it is found that 5% sand size bauxite has the best effect on both gas strength and de-coring 98.5% silica content sand with 70-90 AFS No. with 4% sodium silicate is used. The results indicate that although very good collapsibility is achieved by 2% wood flour, its low gas-strength leads the casting towards various defects.
1989
11
01
128
131
https://www.ije.ir/article_71009_67c241efe419eb2f727ac3fd9096aae5.pdf
International Journal of Engineering
IJE
1025-2495
1025-2495
1989
2
3
Solidification in Copper Continuously Cast in Graphite Moulds
S.H.
Algie
R.
Ghasemzadeh
A mathematical model of heat transfer in continuous casting copper slabs capable of producing experimental data has been constructed and validated against experimental data provided by the management of Copper Refineries Ltd., Townsville plant in Australia. It has been used to predict the effects of major casting variables; metal temperature, casting speed and metal conductivity. The results can be expressed most conveniently through their effects on predicted depth of liquid pool.
1989
11
01
132
143
https://www.ije.ir/article_71010_c0097f2928669a390b2cde68c8aebcfd.pdf
International Journal of Engineering
IJE
1025-2495
1025-2495
1989
2
3
Strengthening Mechanisms in the Aged 2024 and 7075 Aluminium Alloys
S. A.
Jenabali Jahromi
K.
Janghorban
Aluminum 2024 and 7075 alloys which are widely used in aerospace and marine applications were chosen to investigate their strengthening mechanisms. Using differential thermal analysis (DIA), metallography and tension tests, the best solutionizing conditions were determined to be 500±5°C and 2 hours for 2024 and 480?±5°C and 1 hour for 7075 alloy. Aging was performed in the range of 100 to 200°C for various times. It was concluded that the maximum strength in 2024 alloy was developed at l80-190°C after 10 hours and in 7075 alloy at 120°C for 28 hours. In order to determine the strengthening mechanisms in these alloys qualitatively, the T8 treatment (cold work plus aging) was carried out. The results show an increase in the mechanical strength of 2024 alloy whereas the 7075 alloy was not affected appreciably by cold working. It can be concluded that the strengthening mechanism in the 2024 alloy is due to the stress field around the precipitates, whereas in the 7075 alloy it is due to chemical strengthening.
1989
11
01
144
151
https://www.ije.ir/article_71011_c30dfece4cf95d6ba8b9326f830b9a9d.pdf
International Journal of Engineering
IJE
1025-2495
1025-2495
1989
2
3
Heat Transfer in a Column Packed With Spheres
Esmaeil
Khoshravan-Azar
The purpose of the study is to investigate average and local surface heat transfer coefficients in a cylinder packed with spheres. Here the term «local» applies to a single sphere within the bed. Averages are derived from the sixteen different spheres that were instrumented and distributed throughout the bed. The experimental technique consisted of introducing a step - wise change in the temperature of air flowing through the bed and recording the resulting air and ball temperature transients within the bed over a range of Reynolds numbers. An overall correlation of heat transfer with Reynolds number is derived and compared to others available in the literature, and comment is given on the observed patterns in the local coefficients. Comparison is made to theoretical transients.
1989
11
01
152
161
https://www.ije.ir/article_71012_c8f842874e6cdddd180e1985955cbb86.pdf
International Journal of Engineering
IJE
1025-2495
1025-2495
1989
2
3
Application of Boundera Element Method (Bem) to Two-Dimensional Poisson\'s Eqation
M.
Hakimhashemi
Ghodratollah
Karami
BEM can be used to solve Poisson's equation if the right hand side of the equation is constant because it can easily be transformed to an equivalent Laplace equation. However, if the right hand side is not constant, then such a treatment is impossible and part of the equation can not be transformed over the boundary, hence, the whole domain has to be discretized. Although this takes away important advantages of BEM over the Finite Element Method (FEM) in which the whole domain also has to be discretized, but the results are more accurate, and a much coarser mesh can be employed to obtain an equivalent accuracy with less effort in data preparation. In this paper the application of HEM to two - dimensional Poisson's equation is described. A computer program is developed using linear elements to express the geometry and functions. The program, is used to solve the torsion problem (Poisson's equation) and potential flow around a circle (Laplace's equation), and the results are compared with those of analytical methods and FEM.
1989
11
01
162
167
https://www.ije.ir/article_71013_74a39863217e2fc2b478b8b37d16cfbc.pdf