@article { author = {Dehghanian, R.}, title = {Polymer Impregnation of Concrete by Methyl Methacrylate and its Effects on Mechanical Properties and Corrosion of Steel in Concrete}, journal = {International Journal of Engineering}, volume = {2}, number = {3}, pages = {78-83}, year = {1989}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {    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.}, keywords = {}, url = {https://www.ije.ir/article_71002.html}, eprint = {https://www.ije.ir/article_71002_bafc6344c8d75dd7efcf9c094bc7baf7.pdf} } @article { author = {Alemzadeh, Iran}, title = {Sucrose Inversion by Saccharomyces Yeast Cells Immobilized on to Corn Grits}, journal = {International Journal of Engineering}, volume = {2}, number = {3}, pages = {84-87}, year = {1989}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {    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.}, keywords = {}, url = {https://www.ije.ir/article_71003.html}, eprint = {https://www.ije.ir/article_71003_8138a97e303d10bf39dbce4514122c40.pdf} } @article { author = {Ayati, E.}, title = {Rural Road Traffic Accidents in Iran}, journal = {International Journal of Engineering}, volume = {2}, number = {3}, pages = {88-97}, year = {1989}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {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.}, keywords = {}, url = {https://www.ije.ir/article_71004.html}, eprint = {https://www.ije.ir/article_71004_8138a97e303d10bf39dbce4514122c40.pdf} } @article { author = {Ayati, E.}, title = {The Cost of Road Accidents in Iran}, journal = {International Journal of Engineering}, volume = {2}, number = {3}, pages = {98-103}, year = {1989}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {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.}, keywords = {}, url = {https://www.ije.ir/article_71005.html}, eprint = {https://www.ije.ir/article_71005_1bb942b2cff242e349e3a9723136e130.pdf} } @article { author = {Vahidi, B. and Abedi, M.}, title = {Lightning Protection of Ehv Substations in Iran}, journal = {International Journal of Engineering}, volume = {2}, number = {3}, pages = {104-111}, year = {1989}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {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.}, keywords = {}, url = {https://www.ije.ir/article_71006.html}, eprint = {https://www.ije.ir/article_71006_7134834e376e4ed4343a62965f00f1cd.pdf} } @article { author = {Lucas, C.}, title = {Planning Robot Motion in a 2-D Region with Unknown Obstacles}, journal = {International Journal of Engineering}, volume = {2}, number = {3}, pages = {112-117}, year = {1989}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {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.}, keywords = {}, url = {https://www.ije.ir/article_71007.html}, eprint = {https://www.ije.ir/article_71007_a2c381ed4bb08b006ecb748580f8f215.pdf} } @article { author = {Samani, N.}, title = {A Parametric Cathment Erosion Model}, journal = {International Journal of Engineering}, volume = {2}, number = {3}, pages = {118-127}, year = {1989}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {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.}, keywords = {}, url = {https://www.ije.ir/article_71008.html}, eprint = {https://www.ije.ir/article_71008_23bb165a94e91f6a740d3328dcd5c70c.pdf} } @article { author = {Hedjazi, J.}, title = {Improvement of Collapsibility of Sodium Silicate Bonded Cores for Aluminium Casting}, journal = {International Journal of Engineering}, volume = {2}, number = {3}, pages = {128-131}, year = {1989}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {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.}, keywords = {}, url = {https://www.ije.ir/article_71009.html}, eprint = {https://www.ije.ir/article_71009_67c241efe419eb2f727ac3fd9096aae5.pdf} } @article { author = {Algie, S.H. and Ghasemzadeh, R.}, title = {Solidification in Copper Continuously Cast in Graphite Moulds}, journal = {International Journal of Engineering}, volume = {2}, number = {3}, pages = {132-143}, year = {1989}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {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.}, keywords = {}, url = {https://www.ije.ir/article_71010.html}, eprint = {https://www.ije.ir/article_71010_c0097f2928669a390b2cde68c8aebcfd.pdf} } @article { author = {Jenabali Jahromi, S. A. and Janghorban, K.}, title = {Strengthening Mechanisms in the Aged 2024 and 7075 Aluminium Alloys}, journal = {International Journal of Engineering}, volume = {2}, number = {3}, pages = {144-151}, year = {1989}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {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.}, keywords = {}, url = {https://www.ije.ir/article_71011.html}, eprint = {https://www.ije.ir/article_71011_c30dfece4cf95d6ba8b9326f830b9a9d.pdf} } @article { author = {Khoshravan-Azar, Esmaeil}, title = {Heat Transfer in a Column Packed With Spheres}, journal = {International Journal of Engineering}, volume = {2}, number = {3}, pages = {152-161}, year = {1989}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {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.}, keywords = {}, url = {https://www.ije.ir/article_71012.html}, eprint = {https://www.ije.ir/article_71012_c8f842874e6cdddd180e1985955cbb86.pdf} } @article { author = {Hakimhashemi, M. and Karami, Ghodratollah}, title = {Application of Boundera Element Method (Bem) to Two-Dimensional Poisson\'s Eqation}, journal = {International Journal of Engineering}, volume = {2}, number = {3}, pages = {162-167}, year = {1989}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {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.}, keywords = {}, url = {https://www.ije.ir/article_71013.html}, eprint = {https://www.ije.ir/article_71013_74a39863217e2fc2b478b8b37d16cfbc.pdf} }