INTERNATIONAL JOURNAL OF INDUSTRIAL ENGINEERING AND PRODUCTION MANAGEMENT (IJIE) (INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE) (PERSIAN)
Year:2006 | Volume:17 | Issue:4|Papers Count:17

QFD is a powerful tool to translate Voice of Customer to technical specifications and hence can help organizations in a systematic way to determine necessities for design criteria to achieve customer satisfaction. The importance of design needs is determined with help of first matrix of QFD. Since in QFD process most information is in the form of attributes and it is difficult to quantify it accurately, in this paper fuzzy sets are used to quantify the attributes and in addition fuzzy outranking is used to rank design needs.

It is essential for companies to manage the resources that are available to them. The better a company manages these, the better it is at competing with other companies. Traditionally inventory models have attached a cost coefficient to each resource and thus created a single cost equation. This equation is minimized with or without constraints. There are as many models possible as there are companies, since each has a different cost structure and constraints. To day the concept of supply chain is widely extended. Logical progression of the inventory model is to investigate the supply chain that consists of suppliers, manufacturers, distributors and retailers. Each one of them holds inventory in some form to support the requirement of the customer at the end of the chain. A supply chain is considered to be contained of several companies; each one have at least an individual decision maker. This paper considers inventory control problems in supply chain as a multi criteria problem with multiple decision makers. The extended model is a supply chain having four companies that are a manufacturer, a warehouse and two retailers. Customer demand is satisfied by the retailers. The demand at the retailers is satisfied by the warehouse and the warehouse demand is satisfied by the manufacturer. We assume that there exists an independent decision maker at each company. We analyze the inventory control problem at each company as a multi criteria problem with three objectives considering the demand is stochastic. Then having the results of these problems, we solve the multi criteria-multi decision maker problem of the supply chain. We model and solve the problem for stochastic demand, having exponential distribution. The criteria which are used are average inventory capital, number of orders per year and risk of stockouts.

Multi-Attribute Decision Making (MADM) models are applied to solve the selection problems with different and usually conflicting attributes. The uncertainty involved in the parameters of model is due to judgment of Decision Maker (DM) and is usually introduced using fuzzy set theory. The Two-Dimensional MADM Model considers not only the uncertainty of the DM judgments, but the amount of DM's certainty on his judgments. This model uses the certainty factors (CFs), besides the judgments to show the certainty to those judgments. The certainty factor is a crisp number between 0 to 1. This paper develops the two-dimensional MADM Model by fuzzy CF and it is called as fuzzy two-dimensional MADM model. In this paper also a method is proposed to solve the fuzzy two-dimensional MADM model. The experiments conducted shown that using fuzzy two-dimensional MADM model increases the precision and simplicity of decisions.

R2R controllers combine statistical process control and engineering process control. These techniques based on exponentially weighted moving average (EWMA) scheme and adjust input variable based on difference between forecasted and real output. This type of control consist some cost as difference inventory or overtime and etc.In this paper we suggest that first output controls by residual control chart, and if there is out of control case then the process is adjusted, also in this paper with considering cost parameters in adjustment of process, an economic model to optimum design of combination of R2R control and residual control chart is developed.

Department of Civil Engineering, Iran University of Science and Technology Tehran, The fundamentals of electrokinetic (EK) remediation, including removal efficiency from two kinds of contaminated clays, artificially polluted by phenol, were investigated in the laboratory. Results of two one-dimensional tests with initial phenol concentration of 950 ppm (below the adsorption' capacity of clays) are presented in this paper. Besides, soil samples were prepared from Tehran Refinery region to investigate the effects of EK on naturally polluted clay by petroleum hydrocarbons. Results indicated that phenol removal was depended on the ion concentration in clay texture and adsorption capacity of phenol. The phenol removal from 20-80% was achieved in different soils. The results clearly demonstrated that in the case of phenol contaminant, higher removal efficiency was achieved in clay with lower cation concentration. For samples prepared from Tehran Refinery region, EK could not extract petroleum hydrocarbons from soil although a 25% (by volume) mixture of methanol-distilled water was used in anode chamber to conduct in soil texture during electroomotic flow. Adding the methanol to soil texture before the test causes that little volume of petroleum hydrocarbons moved toward the cathode in 40% of sample length and accommodated near the cathode.

Department of Civil Engineering, Iran University of Science and Technology Tehran, The fundamentals of electrokinetic (EK) remediation, including removal efficiency from two kinds of contaminated clays, artificially polluted by phenol, were investigated in the laboratory. Results of two one-dimensional tests with initial phenol concentration of 950 ppm (below the adsorption capacity of clays) are presented in this paper. Besides, soil samples were prepared from Tehran Refinery region to investigate the effects of EK on naturally polluted clay by petroleum hydrocarbons. Results indicated that phenol removal was depended on the ion concentration in clay texture and adsorption capacity of phenol. The phenol removal from 20-80% was achieved in different soils. The results clearly demonstrated that in the case of phenol contaminant, higher removal efficiency was achieved in clay with lower cation concentration. For samples prepared from Tehran Refinery region, EK could not extract petroleum hydrocarbons from soil although a 25% (by volume) mixture of methanol-distilled water was used in anode chamber to conduct in soil texture during electroomotic flow. Adding the methanol to soil texture before the test causes that little volume of petroleum hydrocarbons moved toward the cathode in 40% of sample length and accommodated near the cathode.

Construction of a reservoir may affect the stability of perimeter areas and stimulate sliding of potentially unstable slopes. In this thesis, the issue is first studied and important aspects of the problem and available treatments (including stabilization methods) are extensively reviewed. Next, the study is focused on Golestan II Dam as a case study. As the dam site is covered with collapsible windy deposits namely Loess, the behavior of such soils needs to be scrutinized. Loess is ~ery sensitive to changes of water content, and the stability of loessial slopes decreases dramatically after submergence or saturation. The required soil strength parameters used in the slope stability analysis are obtained from the results reported by the consultant. Some laboratory testing has also been performed by the author to verify the above results. Deterministic and probabilistic stability analysis is performed for two methods of GLE and Modified Bishop. In the probabilistic analysis, some logical values for mean and variation values are assumed for friction angle and cohesion of soil as input data, and failure probability and mean probabilistic safety factors are computed. The total likely volume of sliding mass for all surrounding slopes of at the maximum reservoir capacity of 2nd Golestan Dam is estimated to be 4 percent of the capacity, which means 1,800,000 m3. It is concluded that the sliding could spread in whole shorelines but would not be massive or catastrophic. It is proposed to put some restriction on land use around the reservoir and establish a monitoring program in order to mitigate the sliding hazard.

In this paper, the effect of number of stories, link length (e/l ratio), vertical loading level and strain hardening ratio on seismic over strength factor W of different moment-resisting eccentrically braced steel frames under three different earthquake ground motions is studied. For this purpose nonlinear static push-over analysis is used. Then a new method is presented to evaluate seismic over strength factor of steel moment resisting eccentrically braced frames using nonlinear incremental dynamic analysis (IDA). Incremental Dynamic Analysis (IDA) is an emerging analysis method which involves performing nonlinear dynamic analysis of the structural model under a suite of ground motion records, each scaled to several intensity levels designed to force the structure all the way from elasticity to final global dynamic instability, thus producing curves of response parameterized versus intensity level. To demonstrate the proposed methodology three ground motion records are selected and scaled to several levels of intensity and subsequently applied to three different steel frames with dual lateral load resisting systems of Moment Resisting (MR) and Eccentrically Braced Frames (EBF). DRAIN-2DX is used for all static and dynamic analysis.

The global urbanization process during last two decays reveals the declining position of rural settlements and appearance of a new spatial organization and population distribution in different areas around the world. Is rural settlement vanishing or does Green Movement revitalize the rural settlement are questions in need of consideration.In Iran, despite the rapid urban growth and increasing of urban population proportion during last decays, by considering the economics viability, character, image and physical structure of new urban centers, still the importance of rural settlements is considerable.In this paper, lack of unbalanced population distribution, surplus migration, lack of organization of spatial structure, environmental intrusion, socio-cultural abnormalities and insufficient urban utilities are introduced as major challenges for lack of balance between urban and rural areas. Finally comprehensive economic, social and spatial development planning considering the capacities and features of areas within the consolidated urban-rural framework is proposed as a response to a better understanding of urban rural environments and a strategy for creating a better balance between urban and rural environments.

Estimation of deposit, specially in the mines under operation, is an important factor influencing design and production plan. Along with new exploration, ore estimation requires to be updated. Due to importance of this part of the exploration (ore estimation), many methods have been so far developed to increase reliability and speed. DATAMINE is software developed for this purpose and is one of the most popular. In this research ore estimation in Angouran mine was performed, using latest version of DATAMINE. Data from recent exploration is incorporated, necessary sections are produced and final model of ore deposit is constructed. Three different block size was chosen to study size effect and final selection was made based on the results. Ore deposit in Angouran Mine. Is estimated to be 16.9 million tones of ore with 25.92% zinc and 4.76% lead.

After recognition of some standard solutions, atmospheric corrosion behavior of the alloy WE54 (Mg-5.1wt%Y-1.9wt%Nd-5wt%Zr) has been studied using both potentiostatic and weight loss techniques. Optical microscopy has also been used to study the corrosion mode of the alloy. The results showed that strong carbonated alkaline solutions have no influence on the alloy. While the alloy was resistant in solutions of neutral pH containing no heavy metallic and chlorine ions, they were corroded in strong acidic solutions containing some heavy metallic ions and those including alkaline chlorides. It was found that although intergranular corrosion was the predominant mode of corrosion in all the specimens, pitting was also observed on some point of grain facets.This became vigorous in the final stages of weight loss testing in chloride containing solutions.

Microalloyed steel as a group of high strength low alloy steels has suitable strength and properties. In the microalloyed cast steels, the reliable properties could be achieved by heat treatment. These heat treatments are consist of homogenization, austenatization and normalization or quench with tempering or temperaging. On the other hand, Zirconium has been used rarely as a microalloying element and used often as a controller of sulphide inclusions in the as killed steels. In addition, Zr shows the high affinity for O2, N2 and Carbon; therefore, in fully killed steels, Zr may precipitate as carbide, nitride or carbonitride.In this work, after casting low carbon steel with %0.005 Zr, the determined heat treatments were carried out on it. Then the results compared with the no Zr specimen in each processes, by mechanical tests comprised hardness and charpy impact test, also optical and electron microscopy. The results have shown that % 0.005 Zr addition to the low carbon steel, impact toughness after temperaging increases from 20.1 to 38.4 j, but this variation was not observed after homogenization and quench. Also the hardness after temperaging shows the increasing by 60 RV. In addition the average grain size after homogenization has been decreased from 15.7 to 11.3 mm.

In this research, the effect of mechanical activation of Sarcheshmeh copper concentrate, by means of ball milling, on the efficiency of leaching of copper in ferric chloride has been investigated. It was found that the mechanical activation improved, considerably, the kinetics of copper leaching in ferric chloride media. In 24 hours ball milled sample, copper recovery was 100% in a relatively dilute ferric chloride solution. The activation energy of leaching was decreased from 60.23 kj/mol in no-milled sample to 5.56 kj/mol in 24 hours ball milled concentrate. It was due to the acceleration of chemical reaction, because of increasing of surface reactivity, and acceleration of mass transfer, because of decreasing in diffusion routes in tiny particles. Formation of a sulfur layer, as a reaction product, on the surface of particles during leaching process was confirmed by SEM. Therefore, at the first stage of leaching process of activated concentrate the rate of leaching was considerably high. But at the next stage, after the formation of the dense sulfur layer on the surface of particles with progress of leaching, the leaching rate decreased rapidly.

In the beginning of this study, the fundamental theories of shell has been categorized and according to bending the theory governing differential equations has been derived for cylindrical shell under internal pressure. The system of equations consists of three coupled differential equation of fourth order. Then a displacement function has been introduced which has converted these equations to an 8th order differential equation. Analytical solution of the resultant equation has been performed using fourier series. By imposing the boundery condition on this opening due to oblique nozzle the magnitude of the forces and moments (stress resultants) has been obtained .In addition, the magnitude of stress concentration factor due to combined stresses has been achieved In the end, results are compared with related papers and stress concentration factor curves in critical points of the opening are presented.

The characteristics method and the two-step Lax-Wendroff numerical method are used to analyze the different cases of unsteady compressible flow into the shock-tube. Initially the schemes ability is evaluated by comparing the predicted results with experimental ones. Then, an oscillation in density is imposed on right-hand side of shock-tube and its effect on the whole domain is analyzed. Charging and discharging processes into/or from an opened end pipe are studied for different boundary conditions using method of characteristics. Two suddenly and gradually opening boundary conditions for inlet and outlet ends are applied and it is found that instantly end opening is a suitable assumption for any charging processes, but it is not suitable for discharging one. Finally, analysis of the unsteady compressible fluid flow into a shock-tube filled by lining material or porous media is investigated.

Process of explosive form-cladding for two inhomogeneous plates, which welding them in solid state, involves simultaneous plastic deformation, is investigated analytically and experimentally. Given analytic model, is based on energy method, and considering support conditions, deformation, and impact's critical amount.Two-metal plates are converted to their equivalent homogeneous plate, with a method similar to the analysis of combined beams. Then, replacing equivalent static force, maximum deformation of plate, and possibility of rupture is predicted with respect to plates' mechanical properties. Significant factors, like velocity -which is necessary to compute impact-, is determined and weld ability of inhomogeneous plates is studied with taking into consideration welding window. Then amount of experimental deformation is compared with analytical values and rather good similarities are observed.

A Basic Theoretical- Analytical Analysis of Voltage & Power Stability oh a Point – to - Point HVDC Link (SIF Situation) was presented in [1]. In Addition, Stability Indices based on System Quantities & Parameters have been obtained and formulated. However, it is evident that, after Connecting a HVDC Link in Power Network of Iran and then, connecting to neighboring countries systems, The Structure of baldness network will gets very complex which needs Special Methods to evaluate P&V Stability. These Methods are different from methods of SIF Configuration. In Addition, connecting different HYDC Systems to each other causes interactions between them which is harmful for overall stability. Hence, for confidential of stability and as a important subject, Power Stability at DC Links, it is a privilege to use an analytical method which be simple and rapid in calculating.In this Paper, based on MAP concept and Reduced Power-Flow Jacobian Matrix, two different methods which are named by Standard & Modal Maximum Power Curve (SMPC & MMPC) Methods are presented. These Methods are applicable for designing the Multi - infeed HYDC Systems. This Methods are based on Quasi - Static assumptions with connivance of complicated HYDC Dynamics and Controllers for evaluating Power Stability and it's Margins & Limitson Multi- Infeed HVDC Systems are used. These methods have been used for Dual - Converter HVDC System with help AC/DC Power Flow and Numerical calculating Programs. Then, Analytical results (Power Stability Characteristics) in different conditions & states have been elaborated and a comparison between SMPC & MMPC Methods has performed. At Last, Dynamic Simulations with use of PSCAD-EMTDC Simulator to certify the theoretical analysis results have been shown and discussed.