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Introduction: Musculoskeletal disorders depend on a variety of factors such as inappropriate body posture; heavy lifting; repetitive actions; and mental, physical, and organizational risk factors. The component manufacturing industry is one of the industries in which direct involvement of the worker in the production process is unavoidable. The present study was carried out with the aim of surveying the prevalence rate of musculoskeletal disorders and assessing the upper limb conditions in employees of a component manufacturing company affiliated to Iran Khodro. Methods and Materials: This descriptive-analytical study was performed on 50 employees selected from 5 sections in 2016. In this study, Nordic questionnaire was used to determine the prevalence rate of musculoskeletal disorders and then to evaluate the incidence of musculoskeletal disorders. Results: The results of this study showed that the highest prevalence rates of musculoskeletal disorders in employees of component manufacturing industry during the last 12 months were 58.69, 52.17, and 41.28% in waistline, neck, and wrists, respectively. Conclusion: Considering the high prevalence rate of musculoskeletal disorders in some of the employees in this industry, it is necessary to consider ergonomic issues, optimize workstations, use the mechanical methods for lifting and moving loads, design the standing-sitting work stations, contract with sports halls, gives overtime work, and design and construct ergonomic chairs.

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Decision making about buying pieces (outsourcing) or manufacturing them by factory (insourcing) is the main challenge for manufacturing organizations and strategic issue. This study has aimed to present an appropriate methodology to solve this problem. Using combinative approach of multiple-criteria decision and zero-one multi objective linear programming, the methodology has been able to investigate the decision of manufacturing or buying to develop and increase product portfolio. In the study, primary factors and indices of decision making about manufacturing or buying have firstly been identified by investigating review of literature, and their importance have been measured by experts and the most important factors were selected as final ones. Among final factors, those that had qualitative nature along with insourcing and manufacturing options have been ranked and scored by using analytic hierarchy process (AHP). According to qualitative factors, their amounts and quantitative factors, zero-one multi objective linear programming has been proposed. According to decision -making factors, mathematical model has, finally, made final decision and has selected insourcing (manufacturing inside the factory).

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Manufacturing firms born like humans do and after some stages in their life, die in different ways. With this approach, death is inevitable and just can be delayed. One way to delay this event is having information about the factors influencing that. The purpose of this paper is to study the effects of some factors (like location, size and industrial group) in industrial firms' closure in Yazd province in the third development plan. Data used in this study is gathered from the Yazd Mining and Industry Department database. These are 1539 manufacturing firms that were started their work before 2000, the first year of the Third Development Plan. From these, 175 firms became closed during this period. To determine the effects of these factors, we use the probit regression technique. The results show that firm location (in or out of industrial zones) and firm size doesn't have any effect on closure probability. Moreover the closure probability of older firms is less than the younger counterparts.

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According to the neoclassical approach, input prices as a measure of resources scarcity induce firms to cost-minimizing and efficient allocation of recourses. But when the prices are distorted, the effective competitive inputs are used inefficiently and have resulted in under- or over-utilization of production factors relative to their endowments or allocative inefficiency. In this paper, the shadow cost approach and system of equations are used to estimate allocative inefficiency using the Iran's manufacturing data over the period 1976-2006. The results show that there is strong allocative inefficiency and increasing cost of production of firms in Iran's Manufacturing Sector.

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Economic development is one of the major policies of a country which is concerned to industry and technology on one hand and leads to environmental pollution on the other hand. The experiences of developed countries show that economic development with emphasis on the industry sector, without any attention to environment, can create serious problem against sustainable development. Industrialization has caused increasing energy consumption and therefore air pollution. It's so important to consider the relationship between industrial activities and industrial pollution in developing countries, because industry sector has a basic role in development process of these countries. Therefore the aim of this study is examining and qualifying of linkage between industrial activity and air pollution, using an industry-level dataset of IRAN manufacturing industries during the period 1995-2007. The result of study shows that air pollution is a positive function of energy consumption, industrial activity and physical capital intensity and also is a negative function of labor productivity, fuel price and human skill intensity.

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This paper aims to evaluate the relationship between exports diversification and productivity for nine Iranian manufacturing industries using a panel data approach. Empirical results indicate that productivity and exports have similar trends over the period considered in this study. Indicators such as capital-labor ratio in sub-sectors of the manufacturing and the real effective exchange rate have positive effects on productivity. Exports diversity index has also a positive and significant impact on productivity such that one percentage change in this index increases productivity by 1.8 percent. The effect of trade liberalization on manufacturing productivity is negative and negligible, implying that, to promote productivity, policymakers should consider other fundamental and institutional factors in addition to the foreign trade.

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Despite the importance of diversification and industrial development, finding a suitable way to determine homogeneity and relevance is one of the main challenges in implementing this type of strategy. For this reason, applied studies using new methods of determining homogeneity seems necessary for solving real problems in the world of policy and strategy. Therefore, the purpose of this research is to identify products that are homogenous with the current products of the country's parts and equipment manufacturing industry. The method used in this research is the economic complexity approach that identifies homogenous production opportunities with the current capabilities of the Iranian parts and equipment manufacturing industry, based on the export data of 669 commodity codes under the parts and equipment manufacturing industry between years 2002 to 2017. The findings of this study indicate the existence of 28 homogenous production opportunities with the current situation of Iran's parts and equipment manufacturing industry, which moving towards them will make the industry more diverse and complex. By producing these products, technological capabilities can be accumulated, and more export earnings can be achieved. Accordingly, the production of some types of turbines, engines, vehicle parts, tubes, machine parts and locomotives constitute a significant part of production opportunities in line with the Iranian parts and equipment manufacturing industry. Findings and methods used in this article can be used as a practical guide by industry policymakers and managers.

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Energy is aconsidered as one of the major inputs of production along with other inputs such as labor and capital that contribute to the production process. Moreover, most energy sources have fossil origin and are irreversible, so on the one hand, the basic features of the finitude of other energy inputs to production are distinct and the necessity of energy saving and the possibility of substituting them with the renewable forms are self-evident. Industrial energy demand analysis has always been one of the leading fields of research in economics. This issue is more critical in the case of developing countries, especially those with transitional experiences. In this paper, third generation of dynamic factor demand models for the Iranian manufacturing industries is estimated to analyze the speed of adjustment in factor demands. Using the quadratic functional form, this result was the elimination of energy subsidies in the short term which has a great impact on the industry to reduce energy demand. But, it is believed that in the long run, the intensity of this effect will be diminished. Furthermore, the results show that the speed of adjustment in capital stock of factory industry is very low.

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Entrance of new firms in the industry, according to existing theories, prepares the ground for competition, evolution, growth and innovation that can potentially lead to growth and economic development. This will come true only if the new firms have the ability to survive in economic activity for a reasonable time and are not forced out of the industry in the early years of their entrance. Several reasons have been studied for the exit of industrial firms in the literature of industrial economics. It is believed that the level of industrial technology used by the firm at the early stage of its activities is the main and effective factor that determines the exit time of the firm. This paper is aiming at examining the effects of technology level on exit probability of the new firms in industrial economy of Iran during the years 2001 to 2005. Data of manufacturing firms is extracted from the censuses conducted by the Statistical Center of Iran and the technology level is determined according to OECD classification. Cox hazard model is used in this study to determine the exit probability. The results of this study show that the technology level of industry has had a meaningfully negative impact on the exit probability of new firms. In other words, the firms entering the industry with medium-and high-technology level have a lower probability of exit.  

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Although many firms enter into the market in completely different sizes, recent facts show that the size distribution of new-entrant firms tend to more homogeneity than disparity over time. This is known as industrial dynamics in the literature of industrial economics. The dominant view in this area is learning by doing, in which firms can enter into an activity at any sizes. However, they will learn over time that which size of the market is effective enough to enable them to remain in the market in the long run to give them the chance to adjust their size. Meanwhile, firms that failed to learn it in a reasonable time will have to exit the market. Therefore, the most significant objective of this paper is to review the way of size distribution in firms in arrival time and its adjustment over time in Iran that is not so far taken into consideration well. This subject can have prestigious application for new-entrant firms as well as increasing their lifetime in the market by decreasing adjustment time for incumbent firms. A descriptive-analytical method has been applied for doing this research. The industrial firm data collected by Statistical Center of Iran (SCI) in ten consecutive years are also used for this purpose. The results indicate that the average size of new-entrant firms is smaller than that of incumbent ones. In other words, manufacturing firms in Iran are born smaller in size in comparison with incumbent firms. Additionally, broad size dispersion of the firms at arrival decline during the learning by doing in most industries and tend to more homogenous size distribution. The results have also revealed that although in most selected industries the average size of new entrants has been increased, the intensity of increase is separable in three groups: 1. firms smaller than industry average, 2. firms with close size to the average industry size and 3. firms larger than industry average. Average growth of firm size located in the middle range (group 2) is about half of this measure toward group 1. However, average growth of firm size located in larger groups (group 3) is about half of this measure toward the group 2. This subject as the most essential findings of the industrial dynamics in the economy of Iran indicate that -unlike the usual- small and medium criterion could be modified to suit the type of industry or be influenced by time. Finally, the findings of this research imply that applying absolute definition for a variable conception (small, medium and large firms) cannot be considered rational.

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The main purpose of this paper is to investigate the effect of market structure on innovation and R&D in Iran’s manufacturing sector. To do this, first, statistical data for Iran’s manufacturing sector has been gathered in International Standard Industrial Classification (ISIC) format, then mutual effects of concentration, innovation and R&D, advertising and profitability in different industrial activities have been analyzed using simultaneous equations system and Error Component Tow Stage Least Squares (EC2SLS) during 1996-2007. The results show that industrial concentration has a significant and inverted U-shaped relationship with innovation and R&D. In addition, R&D expenditure declines with increases in profitability. The investigation of the factors affecting manufacturing structure indicates that although innovation and R&D has no effect on manufacturing structure, but profitability and performance of top firms affect their concentration. Our findings exhibit the ineffectiveness of concentration and innovational behavior on industries performance; whereas increasing market concentration results in advertising expenses and innovational behavior of firms raises advertising expenses. Similarly, the lagged and accumulated effects of R&D confirm the existence of an inverted U-shaped relationship between concentration and R&D

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Today, firms depend on technology transfer to establish competitive advantage in the global market place. Since the failure rates in TT projects are surprisingly high, special attention should be given to the identification of factors leading to ineffectiveness of TT projects and factors facilitating TT effectiveness. One of the most important factors affecting TT success is the organization’s competence in dealing with the newly transferred technologies. Every organization must somehow modify its structure, resources and culture to adapt the new technologies. In this paper, we first identified all the significant indicators representing organizational competence and TT effectiveness in Iranian firms. Then we measured the effect of each of organizational competence indicators on TT effectiveness in Iranian electrical manufacturing firms.

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During the past two decades business and manufacturing have observed significant and radical changes. Companies have used automation in the manufacturing, in order to improve quality and competency. It was expected that along with these changes, management accounting systems, which focus on monitoring and analyzing management decisions, should adapt with and encourage the changes. Many authors have claimed that management accounting systems have not helped the suitable business and manufacturing strategies in the new environment. Some even claim that it has hindered investing in advanced manufacturing technology and productivity. This research, by analyzing information collected from 101 Iranian business units from various industries and manufacturing settings, investigates justification basis for capital investment in advanced manufacturing technology. The study demonstrates that there is more correlation between qualitative factors such as; manufacturing capabilities, improved product quality and, competition position with investment justification than quantitative bases such as; accounting rate of return (ARR), internal rate of return (IRR) and, net present value (NPV).

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One of the common problems in manufacturing firms is selecting the best manufacturing system with regard to firm capabilities, market situation, competitors and political and economical issues. Just-In-Time system is one of the best manufacturing systems, which has many benefits. In contrast; implementation of this system is very difficult because of various constraints. Therefore, manufacturing managers encounter the problem of using or not using this system in their firm. In this article, a decision making model based on Analytic Network Process (ANP) is presented for analyzing this problem in a printing factory for finding the appropriate manufacturing strategy. To sum up, the decision making criteria were determined by studying the literature, relevant articles and using Nominal Group Technique among the experts. Then, the related decision making model was prepared by expert interviews. Finally, the best strategy was selected by paircomparison and solving the model.

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Hybrid layered manufacturing is one of the key methods among rapid manufacturing techniques in which a layer of molten metal is deposited on the substrate and desired geometry is completed by stacking the layers. Inexpensiveness, high rates of deposition and great applicability are some of the characteristics of hybrid layered manufacturing. Welding and face milling are the two steps of the process. In welding phase, metal is built up by weld lines to cover a given surface and in milling phase weld beads are truncated to achieve a flat and integrated layer. The focus in this article is to optimize two contradictory objectives, namely reduction in machining volume and increase in deposition rate. Thus, the first task is to formulate the bead model considering the metal build-up effect. Then, the situation needed for achieving quasi-flat layers in welding phase is studied and the unified model is extracted. Moreover, GA is used to find optimum values for the proposed model based on heat and process constraints. Finally the model is verified and conclusions are drawn. This article presents a new criterion by defining the heat constraint for the multi-objective function. Results show that for the 0.8 mm wire ER70S6, optimum values are 8.6 m/min for wire speed and 0.6 m/min for torch speed that yield a deposition rate of 4224 mm3/min without violating heat constraint.

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Parallel manipulators are mechanisms with closed kinematic chains which have been developed in different forms, but these manipulators have several drawbacks such as small workspace, existence of singular points in their workspace, and complex kinematics and dynamics equations that lead to increase of difficulty in their control. In spite of this, this mechanism has been being conventionally used in many different industrial applications such as machining, motion simulators, medical robots, etc. To overcome these drawbacks, design and manufacturing of a manipulator with three translational degrees of freedom are provided. Design of this manipulator was based on the possibility of three translational motions for its end-effector. The manipulator degrees of freedom are obtained via screw theory. Basic features, consisting of forward and inverse kinematics, workspace and singularity analyzes and also velocity analysis, are considered in this paper. A numerical algorithm is implemented to determine the workspace regarding applied joint limitations and the design parameters were extracted based on to achieving to the desired workspace. The robot motion is created by using of pneumatic actuators which receive their command from a pneumatic servo valve. After design steps, the required elements were provided and assembled in a robotic lab. Finally, the simulation results have transparently approved the improved robots.

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Additive manufacturing methods and/or 3D printing have become increasingly popular with a particular emphasis on methods used for metallic materials. Selective Laser Melting (SLM) process is one of the additive manufacturing methods for production of metallic parts. The method was developed in particular to process metal parts that need to be more than 99 percent dense. In this method, according to a predefined pattern, the top surface of the powder layer is scanned by the laser and a local (selective) melt pool is produced in the place of the laser spot which results in a fully dense layer after solidification. In this study, a semi-coupled thermo-mechanical simulation of SLM process is carried out in ABAQUS finite element software. In order to simulate the moving heat flux and update material properties from the powder to the dense solid, the ability of the software for employing user-defined subroutines is employed. Investigation of the residual stress distribution and distortion of a part built using SLM process are the main objectives of this simulation. Results which are presented for two different mechanical boundary conditions show that when the bottom face of the layer is clamped, the top face of the built layer deforms in a concave shape, while the lateral faces of the layer have simply-supported boundary conditions and the bottom face of the layer is free, the part is warped.

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The orientation of part in the additive manufacturing process is one of the most important factors should be considered in the additive manufacturing process. In the additive manufacturing process, the part orientation factor can significantly affect the part properties such as the surface roughness, strength, the manufacturing time and amount of support materials. The manufacturing time is a key factor that can influence the total production cost. Therefore, to minimize the manufacturing time, the optimum orientation of parts should be determined. In this paper, a new method is introduced to estimate the built time of the parts through the additive manufacturing process. According to the proposed method, a practical equation is extracted to estimate the built time of the parts with related to the number of layers and amount of the support materials. The method is capable to estimate the built time of a part associated to the part orientations. The efficiency of the proposed method is demonstrated through a case study in two different type of orientation, and the computational results are compared with the obtained results from the simulations in MankatiUM V5.3 and Repetier-Host software. The average of proposed method relative error in the first type of orientation in comparison with MankatiUM and Repetier-Host software results are, respectively, 5 and 10 percent and for the second type of orientation are 7 and 8 percent. Moreover, calculation cost of proposed method is 140 and 100 times faster than MankatiUM and Repetier-Host software, respectively.

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Additive Manufacturing (AM) or 3D printing is a method to build parts by adding layer-upon-layer of material. The selective laser sintering (SLS) method is one of the most important methods of additive manufacturing processes. The low time and the variety of materials used to build the parts are major advantages of SLS method. The high quality of the product is one of the main goals in the additive manufacturing processes. The part warping is one of the factors that reduce the quality of the products which are built by the SLS process. The hatching patterns and scan algorithms in the SLS process are important factors that affect the product quality. In this paper, the effective parameters of the SLS processes such as the scan vector length and the number of offsets or contours, the laser power, the laser speed, and the hitching spacing are optimally determined to minimize the part warping of the product based on the finite element simulations and Taguchi method. For this reason, SLS process has been modeled on the SLS process. Then, to illustrate and validate the accuracy and efficiency of the proposed method, and the computational results are compared to the obtained results from the experimental tests Using SLS containing CO2 laser. Finally, using the Taguchi design of Experiments, the process parameters have been changed at different levels and optimal parameters have been obtained.

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Most of the organizations employ lean production techniques in a separate manner for eliminating the waste. However, in some cases, in spite of spending huge amount of costs for implementation of these techniques, they could not reach the planned benefits. Therefore, creating a mechanism in order to inform managers regarding the benefits of waste elimination prior to technique execution is one of the vital issues in implementation of these techniques. In this case study, lean production tools have been introduced in a systematic manner by applying value stream mapping, which is one of the main lean production tools in identifying wastes and improvement of opportunities. Furthermore, in order to analyze the results of deploying the above techniques, two simulated models for the current and improved situations have been developed. Finally, by executing the simulated models, two systems have been compared on the basis of key measures, which are lead time production, inventory in process, and unnecessary transportation. The results showed a significant decrease in waste.