@article { author = {Sharifyazdi, M. and Modarres-Yazdi, M.}, title = {Service Level Based Capacity Rationing Procedure for Make-To-Order Manufacturing Systems}, journal = {International Journal of Engineering}, volume = {20}, number = {1}, pages = {1-16}, year = {2007}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {We extend a heuristic method within the framework of “dynamic capacity apportionment procedure” (DCAP) to allocate an existing capacity among the classes with different profit contributions. In general, DCAP is applied when some capacity shortage exists and can not be enhanced in short - run. Our proposed approach is constructed for a make - to - order manufacturing system that produces a variety of products while experiences a burst of demand in excess of capacity. Although, a higher level of profit can be gained  by accepting more orders from higher priority classes at the expense of rejecting some or all of orders of lower priority classes, it may result in elimination of an existing market segment. To avoid this case, which practitioners are very much concerned about it, we propose an approach by maintaining a desired minimum service level for each product class. This method of rationing policy maximizes the expected profit by discriminating product classes while meeting the individual product service level targets set by the management. We also highlight the managerial implications of such a result and identify possible avenues for further research.}, keywords = {Capacity Management,Demand management,Revenue Management,Customer/Product Service Level,Make,to,Order Manufacturing}, url = {https://www.ije.ir/article_71625.html}, eprint = {https://www.ije.ir/article_71625_33a58e515ed4422edf86eed679c1d67f.pdf} } @article { author = {Sadegheih, A.}, title = {A Novel Method for Designing and Optimization of Networks}, journal = {International Journal of Engineering}, volume = {20}, number = {1}, pages = {17-26}, year = {2007}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {In this paper, system planning network is formulated with mixed-integer programming. Two meta-heuristic procedures are considered for this problem. The cost function of this problem consists of the capital investment cost in discrete form, the cost of transmission losses and the power generation costs. The DC load flow equations for the network are embedded in the constraints of the mathematical model to avoid sub-optimal solutions that can arise if the enforcement of such constraints is done in an indirect way. The solution of the model gives the best line additions, and also provides information regarding the optimal generation at each generation point. This method of solution is demonstrated on the expansion of a 5 bus-bar system to 6 bus-bars.}, keywords = {System Planning,Simulated Annealing,Genetic Algorithm,mathematical programming,Artificial intelligence,Iterative Improvement Methods,Heuristic Techniques}, url = {https://www.ije.ir/article_71628.html}, eprint = {https://www.ije.ir/article_71628_24227285b2cfa9d23778a0b46e07d36a.pdf} } @article { author = {Jain, Madhu and Singh, C. J.}, title = {The Approach of Convergence to Stationary State of Multi Server Queue with Balking (TECHNICAL NOTE)}, journal = {International Journal of Engineering}, volume = {20}, number = {1}, pages = {27-34}, year = {2007}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {This investigation deals with multi server queue with balking. The customers arrive in poisson fashion and independent of time, under the assumption that system is initially empty. The number of customers in the system is stochastically increasing and distributed in steady state (stationary state) as required. The expressions for the measure of the speed of convergence from transient state to steady state probability of system are obtained.}, keywords = {Multi Server,Poisson,Stochastic,Steady state,Balking}, url = {https://www.ije.ir/article_71630.html}, eprint = {https://www.ije.ir/article_71630_0ec0470eb169feb3782a39960f596c07.pdf} } @article { author = {Moayed, Mohammad Hadi and Jafari, A.H. and Khavasfar, A.}, title = {An Investigation on the Performance of an Imidazoline Based Commercial Corrosion Inhibitor on CO2 Corrosion of Mild Steel}, journal = {International Journal of Engineering}, volume = {20}, number = {1}, pages = {35-44}, year = {2007}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {The performance of an Imidazoline based commercial corrosion inhibitor on CO2 corrosion of mild steel was investigated in a Cl- containing solution employing linear polarization resistance (LPR), potentiodynamic polarization and monitoring corrosion potential techniques. Experimental results showed that an increase of the commercial inhibitor concentration up to 500 ppm increases the RP value and produces an efficiency of 90 percent. The increase of a test solution temperature at 60°C caused an increase on RP value compared to RP measured at room temperature this suggests adsorption of the inhibitor is promoted by temperature. Plot of c/θ versus inhibitor concentration (c) using different methods showed a straight line with a slope very close to unity, indicating that adsorption of the investigated commercial inhibitor on steel/saturated CO2 solution obeys the Lungmuir adsorption isotherm.}, keywords = {CO2 corrosion,Corrosion inhibitor,Linear Polarization Resistance,potentiodynamic polarization,Lungmuir Adsorption Isotherm}, url = {https://www.ije.ir/article_71631.html}, eprint = {https://www.ije.ir/article_71631_e22e681b47eb6ccd4e5a34e81a594abd.pdf} } @article { author = {Ahmadi, Goodarz and Abouali, O.}, title = {Three-Dimensional Simulation of Airflow and Nano-Particle Beam Focusing in Aerodynamic Lenses(RESEARCH NOTE)}, journal = {International Journal of Engineering}, volume = {20}, number = {1}, pages = {45-54}, year = {2007}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {In this paper airflow, nano-and micro-particle motions in an aerodynamic particle beam focusing system consisting of several lenses, a nozzle and the downstream chamber, was studied. A three-dimensional numerical simulation for the system was presented and the compressible airflow and thermal conditions in the aerodynamic lens system were evaluated. Dilute particle concentration was assumed so that the particle motion does not affect the flow field and a one-way coupling is assumed. In the computational model, an intermediate chamber with different size skimmers downstream of the nozzle was also considered. The simulation results for 3-dimensional flow field showed that the assumption of axi-symmetric flow is reasonable at the downstream of the nozzle. The performance of the lens with air as carrier gas for focusing nano-and micro-particles was discussed. The results showed that the sub 30 nm particle trajectories are three-dimensional and the assumption of the axi-symmetric particle motions is not valid.}, keywords = {Aerodynamic,Lenses,Nano,Micro,Particles}, url = {https://www.ije.ir/article_71633.html}, eprint = {https://www.ije.ir/article_71633_22337b06ec5316ef13f3a9f5a25964cb.pdf} } @article { author = {Assempour, A. and Ganjiani, M.}, title = {The Performance of Karafillis-Boyce Yield Function on Determination of Forming Limit Diagrams}, journal = {International Journal of Engineering}, volume = {20}, number = {1}, pages = {55-66}, year = {2007}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {Forming Limit Diagrams are useful tools for evaluation of formability in the sheet metals. In this paper the effects of yield criteria on predictions of the right and left-hand sides of forming limit diagrams (FLDs) are investigated. In prediction of FLD, Hosford 1979, “Karafillis-Boyce” (K-B) and BBC2000 anisotropy yield functions have been applied. Whereas the prediction of FLD is based on the “Marciniak and Kuczynski” model, thus a numerical approach using the Newton-Raphson method has been used. Forming Limit Diagrams have been obtained for Al 6111-T4 and AA5XXX alloys and results have been compared with published experimental data. Results indicate that predictions of FLD are very sensitive to selection of yield criterion. Also it was found that the FLD of K-B yield function has a better agreement than that by other yield criteria.}, keywords = {Marciniak and Kuczynski Model,Karafillis and Boyce,Hosford 1979,BBC2000,Yield Function,Newton,Raphson Method}, url = {https://www.ije.ir/article_71635.html}, eprint = {https://www.ije.ir/article_71635_e8449eb717af461308b1967cab47200f.pdf} } @article { author = {Mossavinik, V. and Baradaran Rahimi, A.}, title = {Axi-symmetric Stagnation–Point Flow and Heat Transfer Obliquely Impinging on a Rotating Circular Cylinder}, journal = {International Journal of Engineering}, volume = {20}, number = {1}, pages = {67-82}, year = {2007}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {Laminar stagnation flow, axi-symmetrically yet obliquely impinging on a rotating circular cylinder, as well as its heat transfer is formulated as an exact solution of the Navier-Stokes equations. Rotational velocity of the cylinder is time-dependent while the surface transpiration is uniform and steady. The impinging stream is composed of a rotational axial flow superposed onto irrotational radial stagnation flow normal to the cylinder with strength Γ. The relative importance of these two flows is measured by a parameter γ. The governing parameters are the stagnation-flow Reynolds number Re = Γa2/2υ and the dimensionless transpiration S = U0/Γa, where a is cylinder radius, ν is kinematic viscosity of the fluid and U0 is the transpiration rate. An exact solution is obtained by reducing the Navier-Stokes equations to a system of differential equations governed by Reynolds number and the dimensionless wall transpiration rate. Dimensionless shear stresses corresponding to all the cases increase with the increase of Reynolds number and suction rate. Heat transfer is independent of cylinder rotation and its coefficient increases with the increasing suction rate, Reynolds number and Prandtl number.}, keywords = {Oblique Stagnation Flow,Axisymmetric,time,Dependent Rotation,Dependent Heat Transfer,Transpiration,Exact Solution}, url = {https://www.ije.ir/article_71638.html}, eprint = {https://www.ije.ir/article_71638_2755d2ce35983fd46d09a3dd57e0fa75.pdf} } @article { author = {Haidarie, A. and Farievar, S. and Kahrom, Mohsen}, title = {The Effect of Square Splittered and Unsplittered Rods in Flat Plate Heat Transfer Enhancement}, journal = {International Journal of Engineering}, volume = {20}, number = {1}, pages = {83-94}, year = {2007}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {A square splittered and unsplittered rod is placed in a turbulent boundary layer developed over a flat plate. The effect of the resulting disturbances on the local heat transfer coefficient is then studied. In both cases the square rod modifies the flow structure inside the boundary layer. As a result, a stagnation point, a jet and wake area are generated around the square rod, each making a contribution in disturbing the boundary layer and effect on the heat transfer coefficient from the neighboring flat plate. Effects of distance of square rod from the flat plate, inclusion of a splitter at the downstream of the rod, splitter length and its location relative to the square rod on local heat transfer coefficient in a variety of cases are studied. It is concluded that the effect of stagnation point is always to reduce the local heat transfer; the jet and wake both contribute on increasing heat transfer from the flat plate. The contribution of splitter on disturbing the boundary layer is not significant when compared to the effect of square rod when used alone. Splitter on its own contributes to controlling the wake effect and by changing the wake size and its structure reduces the wake effect on heat transfer. However these all depend on geometrical size and positioning of the splitter.}, keywords = {Heat transfer enhancement,Jet,Splitter,Square Rod,Turbulent Boundary Disturbed,Wake}, url = {https://www.ije.ir/article_71640.html}, eprint = {https://www.ije.ir/article_71640_8f03ddbea91522f88c6373ac9c1c3e6b.pdf} } @article { author = {Soleimani Alamdari, G.}, title = {Simple Functions for Predicting Thermodynamic Properties of Ammonia-Water Mixture (RESEARCH NOTE)}, journal = {International Journal of Engineering}, volume = {20}, number = {1}, pages = {94-104}, year = {2007}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {The engineering calculation and simulation of absorption refrigeration systems require the availability of simple and efficient functions for the determination of thermodynamic property values of the operating fluid. This work presents a set of five simple and explicit functions for the determination of the vapor - liquid equilibrium properties of the ammonia-water mixture. The functions are constructed by least square method for curve fitting using the valid available data in the literature. The presented functions are valid for - 20 ≤ T ≤ 140º C, 0.2 ≤ P ≤ 100 bar, and the entire composition range (i. e. 0 ≤ x ≤ 1) which cover the region within which absorption cycles commonly operate. Obtained results are compared in detail with other correlations in the literature in graphical and statistical forms and reasonable accuracy are observed. Standard deviation of presented functions are 3.44 kJ/kg for enthalpy of saturated liquid mixture, 14.06 kJ/kg for enthalpy of saturated vapor mixture, and 0.0123 kg - NH3/kg - mix for ammonia mass fraction in vapor phase.}, keywords = {Ammonia,Water Mixture,Thermodynamic properties,Absorption Refrigeration Systems}, url = {https://www.ije.ir/article_71642.html}, eprint = {https://www.ije.ir/article_71642_61583bc6b5d1f0c828b0244660c6819f.pdf} }