@article { author = {Salajegheh, Eysa}, title = {Efficient Optimum Design of Steructures With Reqency Response Consteraint Using High Quality Approximation}, journal = {International Journal of Engineering}, volume = {10}, number = {2}, pages = {61-70}, year = {1997}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {An efficient technique is presented for optimum design of structures with both natural frequency and complex frequency response constraints. The main ideals to reduce the number of dynamic analysis by introducing high quality approximation. Eigenvalues are approximated using the Rayleigh quotient. Eigenvectors are also approximated for the evaluation of eigenvalues and frequency responses. A two point approximation is used to approximate the functions under consideration. After the substitution of the approximate functions into the original optimization problem, the dynamic analysis of the structure is not necessary in the specified move limits. The sensitivities of the eigenvalues and eigenvectors are calculated analytically. In the problems under consideration repeated eigenvalues occur. Thus the sensitivities are evaluated for repeated eigenvalues.}, keywords = {Frequency Response Constraints,Optimum Design,Two Point Approximation}, url = {https://www.ije.ir/article_71174.html}, eprint = {https://www.ije.ir/article_71174_2769c64e7f801d1d97995ec9b3d9bdce.pdf} } @article { author = {Soltani, J.}, title = {Computer Simulation of Converter Fed Synchronuse Machine Drives Contaning Space Harmonics}, journal = {International Journal of Engineering}, volume = {10}, number = {2}, pages = {71-84}, year = {1997}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {In this Paper, complete models of three and six phase self commutated synchronous machine drives are presented, considering the effects of both time and space harmonics. First, the equations for calculation of machine inductances are developed. Next, "thyristor-inverter-electric machine" set is modeled in order to derive all the equations for conduction and commutation states. Finally, the results of computer simulation are demonstrated.}, keywords = {Synchrodrive,time,Space Harmonics}, url = {https://www.ije.ir/article_71175.html}, eprint = {https://www.ije.ir/article_71175_426fa8c8e3030b502de3e8ee52b26714.pdf} } @article { author = {Azhdari, K.}, title = {Magnetic and Electerical Resistivity Behavior of Amorphous Ni Co P Films}, journal = {International Journal of Engineering}, volume = {10}, number = {2}, pages = {85-90}, year = {1997}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {Magnetic and Electrical Resistivity Study of Electroless Amorphous Ternary System (Ni-Co-P) show a qualitative dependence of crystalline phases formed during transformation on the annealing temperature and composition. Electrical Resistivity values increases with increase in cobalt content and samples with higher resistivity show lower temperature coefficients. The Initial increase in magnetization is due to separation of crystalline magnetic phases (a-Cobalt and f.c.c. Nickel), and tends to decrease by formation of equilibrium phases at higher temperature.}, keywords = {Magnetic Resistivity,Electrical resistivity,a,Cobalt,FCC Nickel,Ni,CO,P}, url = {https://www.ije.ir/article_71176.html}, eprint = {https://www.ije.ir/article_71176_a78958df8eb72c72fde23a394e615190.pdf} } @article { author = {Prabhu, A. and Jahanmiri, Mohsen}, title = {A Mthod for Generating the Turbulent Intermittency Function}, journal = {International Journal of Engineering}, volume = {10}, number = {2}, pages = {91-102}, year = {1997}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {A detection method based on sensitization of a squared double differentiated signal is developed which discriminates the turbulent zones from laminar zones quite accurately. The procedure adopts a variable threshold and a variable hold time of the order of the Kolmogorov time scale. The output file so generated, includes all the information for further analysis of the turbulent signal.}, keywords = {Turbulence,Intermittency Function,Transitional Flow}, url = {https://www.ije.ir/article_71177.html}, eprint = {https://www.ije.ir/article_71177_3aea50abc24e0bf1c38da4aa88517a7e.pdf} } @article { author = {Rostami, AA and Farmanzadeh, D. and Najafpour, Ghasem}, title = {Solubility of Hydrogen Sulfid and Sulfur Dioxide in Triethylen Glycol, Tetra Ethylene Clycol and Diethanol (TECHNICAL NOTE). AMINE SOLUTION}, journal = {International Journal of Engineering}, volume = {10}, number = {2}, pages = {103-110}, year = {1997}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {Natural gas sweetening is an important process which is used for treatment of sour gases. The measurement of solubility is also considered in most sweetening processes such as that of Townsend process. Therefore, experimental measurements would be helpful to determine the equilibrium data under actual equilibrium conditions for the gas treatment plants. In this research solubility of hydrogen sulfide and sulfur dioxide in various solvents was determined within a wide range of temperatures, 23 to 60ْC. Solubility of hydrogen sulfide in 98 per cent tetraethylene glycol was measured at room temperature in a static pool and in an agitated vessel, were found to be 14.11 and 28.05 mg/g of solvent, respectively. Sulfur dioxide solubility which was also measured at 23ْC in a static pool and an agitated vessel, were 23.72 and 262.77 mg/g of solvent, respectively. Solubility is generally reduced by increasing temperature in most solvents, except that in diethanol amine in which it is in reverse order. The maximum solubility of gases at 93 percent diethanol amine at 60ْC, was obtained. These were 319.31 and 549.14 mg/g of solvent, in static vessel and an agitated vessel, respectively. Based on experimental results, maximum solubility was obtained in an agitated vessel at lower range of temperature, except for diethanol amine for which solubility were maximized at higher range of temperature.}, keywords = {Diethanol Amine,Hydrogen Sulfide,Gas Sweetening,Solubility,Sulfur Dioxide,Tetraethylene Glycol,Townsend Process,Triethylene Glycol}, url = {https://www.ije.ir/article_71178.html}, eprint = {https://www.ije.ir/article_71178_e6f2166e22765933594f05328b578843.pdf} } @article { author = {Sun, Y. and Bell, T.}, title = {Glow Discharge Depth Profiling a Powerful Analytical Technique in Surface Engineering (TECHNICAL NOTE)}, journal = {International Journal of Engineering}, volume = {10}, number = {2}, pages = {111-119}, year = {1997}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {A variety of analytical techniques have been developed and employed to characterize the surfaces, subsurfaces and interfaces of surface engineering systems. They provide important information for quality control, process optimization and further development. Since the mid 1980's, glow discharge spectrometry (GDS) has emerged as an important and versatile technique for rapid depth profiling analysis of the chemical compositions of surface layers with thickness ranging from a few nanometers to several tens of micrometers. The basic principles of GDS are first discussed briefly in the present paper. Then applications of the technique to various surface engineering systems, including PVD coatings, ion implanted surfaces, diffusion layers and multi-layer coatings, are demonstrated to highlight the important role of this analytical technique in surface engineering.}, keywords = {PROFILE,Depth Profiling,Surface Engineering,Coatings}, url = {https://www.ije.ir/article_71179.html}, eprint = {https://www.ije.ir/article_71179_ea591ec5f14feadec5c27ba409c6cef3.pdf} }