@article { author = {Safekordi, A. A. and Alemzadeh, Iran and Yaghmaei, S. and Vossoughi, M.}, title = {Some Investigation on Bioremediation of PahsContaminated Soil in Iran Tar Refinery}, journal = {International Journal of Engineering}, volume = {15}, number = {1}, pages = {1-10}, year = {2002}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {The main purpose of this research is studying the possibility of bioremediation of polycyclic aromatic hydrocarbons (PAHs) contaminated soils in Iran’s tar refinery area located in Isfahan. For many years a great quantity of tar produced by neighboring metallurgical plant has been stored in lagoons as natural reservoirs, causing the contamination of soil in this area. Microorganisms capable of transforming PAHs, such as anthracene and phenanthrene, are commonly found in soil, especially soil previously contaminated with PAHs and microorganisms capable of transforming PAH compounds have been used to decontaminate soil. In the first phase of our study, we focused on isolation and purification of PAHs utilizing microorganisms from soil. The results of site characterization and biofeasibility testing have shown the presence of a viable native population of community of specific contaminant-degrading microbes already in the site. Therefore, biostimulation becomes an available option. It is the essence of this option that the native (indigenous) microbial community is found to be capable of degrading the target site contaminants (PAHs) if managed properly. In this research for the first time in Iran we have studied, the possibility of bioremediation of PAHS contaminated sites by indigenous microorganisms. Microbiological analysis of soil chronically exposed to coal tar of an industrialized area near the city of Isfahan, resulted in the isolation of some bacteria which degraded, each of, naphthalene, phenanthrene, and, anthracene in an aqueous solution, when grown for two weeks in pure culture with organic nutrients. The initial PAH concentration was at the water solubility level and degradation proceeded to no detectable level, in some cases. They grew well at 25°C to 30°C. The use of these microorganisms may be an attractive alternative to existing physiochemical method for the remediation of PAH in the environment.}, keywords = {Bioremediation,Coal Tar,PAHs,Soil}, url = {https://www.ije.ir/article_71322.html}, eprint = {https://www.ije.ir/article_71322_1fd4668094a3b9b83bc82edf583947a2.pdf} } @article { author = {Makarchian, M.}, title = {An Experimental Study of Foundation Underpinning by Piles}, journal = {International Journal of Engineering}, volume = {15}, number = {1}, pages = {11-22}, year = {2002}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {Existing buildings sometimes experience excessive settlement under their design loads or face the prospect of excessive settlement in the future if a change of building use is required and increased foundation loadings will occur. Several methods of foundation enhancement are available to arrest settlements or improve the future performance of existing foundations including the method of underpinning by piles. To investigate further the behavior of underpinning piles, which are installed beneath a settling foundation, two series of controlled model underpinning tests have been carried out in normally consolidated clay with different loading levels and different pile lengths. In this paper, the test procedure is described, and results of the two different test series are presented. Some comparisons are also made between the observed behavior and predicted from numerical finite element analyses and these are discussed briefly.}, keywords = {Underpinning,Foundation,pile,Model Test,Settlement}, url = {https://www.ije.ir/article_71324.html}, eprint = {https://www.ije.ir/article_71324_af9b06e4c7205840b6094b1869420408.pdf} } @article { author = {Wilson, David and Mohammadi, M.}, title = {An Experimental Investigation of Bridgeflow II Kerb Channel Units}, journal = {International Journal of Engineering}, volume = {15}, number = {1}, pages = {23-40}, year = {2002}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {The results of an experimental investigation of kerbside bridge deck drainage units are presented. The conveyance capacity, resistance coefficients and sediment transporting efficiencies of different types of drainage unit used in shallow bridge drainage decks are examined over a range of bed gradients likely to be encountered in practice. The use of a V-shaped cross section is shown to be particularly effective in transporting sand and gravel material along the channel, and sediment threshold equations are presented. The overall hydraulic resistance of kerbside drainage units, together with the effect of joints and rib roughness on the walls of some other types of unit, is also illustrated.}, keywords = {Experimental Investigation,Kerbside Bridge Drainage Units,Conveyance Capacity,V,Shaped Bottom Cross,section,Sediment Threshold,Hydraulic resistance,Rib Roughness}, url = {https://www.ije.ir/article_71326.html}, eprint = {https://www.ije.ir/article_71326_bd6b9456acf4da242a004d6d6501ec1b.pdf} } @article { author = {Haji, Rasoul and Haji, Alireza}, title = {Optimum Aggregate Inventory for Scheduling Multi-product Single Machine System with Zero Setup Time}, journal = {International Journal of Engineering}, volume = {15}, number = {1}, pages = {41-48}, year = {2002}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {In this paper we adopt the common cycle approach to economic lot scheduling problem and minimize the maximum aggregate inventory. We allow the occurrence of the idle times between any two consecutive products and consider limited capital for investment in inventory. We assume the setup times are negligible. To achieve the optimal investment in inventory we first find the idle times which minimize the maximum aggregate inventory for a given sequence of production runs and for any arbitrary cycle time T . Then, we show that these values of idle times, for the given sequence, are also optimal idle times for any other sequence. The result is an easy-to-apply rule that greatly simplifies the task of scheduling to achieve minimum required investment in inventory.}, keywords = {Economic Lot Scheduling,Inventory,Optimal Investment,Systems Engineering}, url = {https://www.ije.ir/article_71328.html}, eprint = {https://www.ije.ir/article_71328_e94779efc53cc6c895b94c653897c5cc.pdf} } @article { author = {Singh, C. J. and Sharma, G. C. and Jain, Madhu}, title = {Diffusion Process for Multi - Repairmen Machining System with Spares Aand Balking}, journal = {International Journal of Engineering}, volume = {15}, number = {1}, pages = {49-56}, year = {2002}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {In this paper we describe G/G/R+s multi- repairmen machining system with balking. The system consists of M operating machines, S spare machines, R permanent and s additional repairmen. Assuming the discrete flow of machines by continuous one, the diffusion approximation technique for the machine repair system has developed. The system will be in normal working mode if there is M operating machines. When there are less than M and ≤ m, the system is called as short system. The failure rates of operating units in short and normal modes are different. By using the mean and square coefficient of variation of failure and repair time distributions, the queue size distribution has been established. Various performance indices viz. expected number of failed machines, average operating machines etc. have been derived.}, keywords = {Queue,Machine Repair,Warm Standby,Diffusion Approximation,Additional Repairmen,multi,Repairmen,Balking}, url = {https://www.ije.ir/article_71330.html}, eprint = {https://www.ije.ir/article_71330_f872b21d47efe66f3ad4b4dd25865709.pdf} } @article { author = {Singh, C. J. and Sharma, G. C. and Jain, Madhu}, title = {G G r Machine Repair Problem with Spares and Additional Repairman (TECHNICAL NOTE)}, journal = {International Journal of Engineering}, volume = {15}, number = {1}, pages = {57-62}, year = {2002}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {The machine repair problem with spares and additional repairman is analyzed. The interfailure and repair times of the units are general identical and independently distributed. The failure and repair rates are assumed to be state dependent. Using diffusion approximation technique, we obtain the queue size distribution under steady state. The average number of failed units, average number of operating units in the system and the probability of the system being short are obtained by using the queue size distribution.}, keywords = {Queue,Diffusion,Machine Repair,Warm Standby,Additional Repairman,State Dependent Rate}, url = {https://www.ije.ir/article_71332.html}, eprint = {https://www.ije.ir/article_71332_abbc81770714e70a7008b25f23012ed0.pdf} } @article { author = {Saidi Mehrabad, Mohammad}, title = {Application of Markov Processes to the Machine Delays Analysis}, journal = {International Journal of Engineering}, volume = {15}, number = {1}, pages = {63-72}, year = {2002}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {Production and non-productive equipment and personnel delays are a critical element of any production system. The frequency and length of delays impact heavily on the production and economic efficiency of these systems. Machining processes in wood industry are particularly vulnerable to productive and non-productive delays. Whereas, traditional manufacturing industries usually operate on homogeneous raw material, in a restricted environment with closely controlled processing guidelines. The logging industry must continually deal with a raw material that comes in many different shapes, sizes and performs in an environment that is different from site to site. Furthermore, loggers; rarely have the opportunity to follow a predetermined production sequence, as men and machines must maneuver as conditions dictate. As a result machining systems can experience a broad range of delays that vary widely in frequency and length. The purpose of this study was to apply Markov process models to the analysis of delay times in machining processes. Such an approach will permit the random components of machining process to be integrated into a flexible mathematical model, using theoretical probability distributions, and providing analytic solutions to proportions of productive delay time.}, keywords = {Delays Analysis,Markov process}, url = {https://www.ije.ir/article_71334.html}, eprint = {https://www.ije.ir/article_71334_eb649b027a7fd976eac1e11fbb5a5839.pdf} } @article { author = {Abdollahzadeh, M. and Taghizadeh Kakhki, H.}, title = {Allocation of Posts to a Tele-Communication Center Through Kavos (RESEARCH NOTE)}, journal = {International Journal of Engineering}, volume = {15}, number = {1}, pages = {73-78}, year = {2002}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {Every phone company customer in a given region receives phone services from a switching center through intermediate points called kavos. The problem addressed in this paper is where to locate this central facility and the kavos, how many of them and with what capacity, so that the total cable length is minimized. This problem can be formulated as a 0-1 mixed integer program; However, because of the scale of the problem, it is not possible to solve it in a reasonable amount of time with the existing software; Hence a solution procedure is developed which solves the problem very efficiently. In addition, to make the model more realistic, and to be able to take into account the decision maker’s preferences, an interactive program has been developed.}, keywords = {Two,Level Facility Location,large,Scale Mixed Integer Programming,Telecommunication Networks}, url = {https://www.ije.ir/article_71335.html}, eprint = {https://www.ije.ir/article_71335_cf4cab92f8724be843ac3ee100162825.pdf} } @article { author = {Zhu, W. X. and Smith, D. J. and Farrahi, G. H. and McMahon, C. A.}, title = {Influence of Residual Stress on Fatigue Life of Hot Forged and Shot Blasted Steel Components}, journal = {International Journal of Engineering}, volume = {15}, number = {1}, pages = {79-86}, year = {2002}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {Hot forging is a common manufacturing process for the production of large quantities of engineering components. Residual stresses are developed in forged components as a result of various aspects of the manufacturing process, including subsequent cooling, and heat treatment. Residual stresses can significantly affect the deformation and fatigue failure of materials. Hot forged EN15R steel bars were studied. Four batches of specimens representing different stages of the forging process were employed. Residual stresses introduced by the process were measured by X-ray diffraction technique. Fatigue tests were carried out on fourteen specimens from each batch. Weibull distribution for fatigue data was considered. It was found that compressive residual stress had no benefit under low cycle fatigue (LCF) because the residual stresses were completely relaxed due to the large plastic deformation but had a beneficial effect on high cycle fatigue (HCF).}, keywords = {fatigue,Residual stresses,Hot Forging,X,ray diffraction}, url = {https://www.ije.ir/article_71337.html}, eprint = {https://www.ije.ir/article_71337_cbf27a0671c0dfaf1dd18746c50dbc89.pdf} } @article { author = {Kianvash, A.}, title = {Effect of Post-Sintering Annealing Treatment on Magnetic Properties of Some Nd Fe b Based Magnets}, journal = {International Journal of Engineering}, volume = {15}, number = {1}, pages = {87-96}, year = {2002}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {Effects of post-sintering annealing treatment between 300 and 1000ºC for up to 8 hrs time periods followed by either furnace cooling (FC) or air-cooling (AC) on the hard magnetic properties of some Nd-Fe-B based sintered magnets was investigated. It was shown that the intrinsic coercivity (Hci), second quadrant demagnetization loop shape and thus the energy density (BH)max varied considerably as a result of the annealing treatment. However, no significant changes occurred in the remanence (J) values of the magnets. Annealing at 500ºC for 1 hr followed by FC resulted in a considerable deterioration in the demagnetization loop shapes and thus in (BH)max values in all the magnets. These changes were almost recoverable. By annealing at 500ºC, followed by AC, no deterioration in the demagnetization loop shape occurred for any of the magnets and thus there were some increases in (BH)max values of the magnets due to increase in their Hci values. The highest Hci in magnets A and C was obtained by a standard annealing treatment for 1 hr at 600ºC, while in magnet B, the highest Hci occurred after an annealing treatment for 2 hrs at 500ºC, both followed by AC. No deterioration in the demagnetization loop shape was identified for any of the magnets either in FC or AC from 600ºC. However, the coercivity enhancement in magnet A and in particular, in magnet B, was found to be much higher after AC than FC. In all the annealing treatments, the improvement in Hci and/or (BH)max values occurred in the first 1 or 2 hrs of annealing. Any further annealing beyond these times resulted in significant falls in the magnetic properties. Thus, long term annealing for up to 300 hrs at 400ºC resulted in dramatic reductions in the hard magnetic properties, which could only be partially recovered. This behavior has been related to the oxidation of the magnets during long term annealing in a roughing pump vacuum. In this paper, the changes in Hci and (BH)max values during these annealing treatments are related to possible microstructural changes reported elsewhere.}, keywords = {Nd,Fe,B Based Permanent Magnets,Post,Sintering Annealing Treatment,Intrinsic Coercivity,Remanence,Energy density,Demagnetization Loop Shape}, url = {https://www.ije.ir/article_71339.html}, eprint = {https://www.ije.ir/article_71339_e44e177e82f63d3c972616a76f1e4ad9.pdf} } @article { author = {Kasaeyan, M. and Abbaspour, M.}, title = {Application of Boundary Element Method to 3 D Submerged Structures With Open Ends (RESEARCH NOTE)}, journal = {International Journal of Engineering}, volume = {15}, number = {1}, pages = {97-104}, year = {2002}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {This paper presents a three dimensional application of direct Boundary-Element Method (BEM) for computing interaction of sinusoidal waves with a large submerged open bottom structure near the floor with finite depth. The wave diffraction problem is formulated within the framework of linearized potential theory and solved numerically with direct BEM. A computer program based on BEM is developed to calculate the wave-exciting hydrodynamic forces. Comparisons of the results with those obtained by several previous investigators reveal a good agreement. In this study, we are primarily interested in the wave forces on a shell defined by an open-end surface. The formulation of this problem is similar to that for a solid, except that the solution is contained in a singular integral equation. This solution is extended to a cylindrical open bottom structure and the wave forces are compared to those for the corresponding seated structures. This method, however, can be applied for any 3-D geometrical objects with or without open ends.}, keywords = {BEM,scattering,Greens Function,Boundary Integral,boundary conditions,Submerged}, url = {https://www.ije.ir/article_71341.html}, eprint = {https://www.ije.ir/article_71341_beedbfcd4cb5c4fae36cf79da01379de.pdf} } @article { author = {Latifi, M. and Amirshahi, S. H. and Shams-Nateri, A.}, title = {Color Matching of Blends Prepared From Black and White Fibers by Neural Networks (TECHNICAL NOTE)}, journal = {International Journal of Engineering}, volume = {15}, number = {1}, pages = {105-108}, year = {2002}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {The color of the blends of pre-colored fibers depends on the ratio of each fiber in the blends. Some theories have been introduced for color matching of blends of pre-colored fibers. Most however, are restricted in scope and accuracy. Kubelka and Munk presented the most applicable theory, which is still used in industry. In this work, the classical Kubelka-Munk method for color prediction of a series of grays, prepared from different ratio of black and white is compared with new technique, which apply neural networks. Thirteen different blends with different ratio of virgin and black fibers were prepared. The reflection of samples was measured and then a two layers network was designed. The modified back-propagation learning strategy was applied. The Sum of Squares Error was calculated for evaluation of methods. Results showed better prediction for networks in comparison to Kubelka-Munk algorithm.}, keywords = {Color Matching,Pre,colored Fibers,Neural Network,Blend}, url = {https://www.ije.ir/article_71342.html}, eprint = {https://www.ije.ir/article_71342_160aa88a60e4b290eac840c3254398a9.pdf} }