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Performance appraisal is considered as an important and critical function in facilitating organization effectiveness in the field of human resource management. In recent years, there has been more attention toward the role of performance appraisal system, became it is believed that an effective performance appraisal system can present many advantages for the organization and its members. Performance appraisal system has gained considerable attention from public sector especially in Iran and in recent years the government has tried to implement this system by improving its present status among managers, supervisors/experts and employees. In this article, the degree of past and present performance appraisal effectiveness is studied and in this regard 7 hypothesis and its referent questions are presented. By testing in a comparative method the questionnaire forms are distributed among certain members of experts in the ministry of economic affairs. The results indicate a comparison between past present performance appraisal system show a remarkable move toward a better system in the future. At the end, recommendations for developing and improving a system of performance appraisal system for public employees also removal of current difficulties and upgrading the effectiveness of the system are presented.

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This study was conducted to investigate direct and maternal effects on some economic traits in north Iranian native fowls. Traits considered were body weight at 1 day of age (BW1), body weight at 8 weeks of age (BW8), body weight at 12 weeks of age (BW12), egg number (EN) during the first 12 weeks of laying period, egg weight at 1st day of laying (EW1), mean egg weight at 28th, 30th and 32nd weeks (MEW), age at sexual maturity (ASM) and weight at sexual maturity (WSM). The data were analyzed using Restricted Maximum Likelihood procedure fitting an animal model with DFREML software package. A series of six different animal models with and without maternal effects were fitted for all traits, and the best model for each trait was chosen based on log-likelihood ratio tests (LRT). The direct heritability (h2) estimates ranged from 0.03 (BW1) to 0.51 (MEW). Maternal effects were significant on all the traits studied. The estimates of maternal heritability (m2) ranged from 0.01 (BW8, WSM, ASM, EW1) to 0.15 (BW1), and the estimates of maternal environmental variance as a proportion of phenotypic variance (c2) varied from 0.02 (WSM, EW1, EN) to 0.23 (BW1). The correlations between direct and maternal additive genetic effects (ram) were negative for all traits. These results indicate that genetic selection schemes for body weight and egg traits should utilize models incorporating both direct and maternal effects.

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Tensegrities are a kind of spatial structural system composed of cable (in tension) and strut (in compression). Stability of this system is provided by the self stress state between tensioned and compressed elements. In this paper, co-rotational method is used for study geometrical nonlinear analysis of tensegrity structure and analysis of the effect of pre-stress on it. This approach unlike other available approach in nonlinear static analysis, the major part of geometric non-linearity is treated by a co-rotational filter. The function of CR formulation is to extract relevant deformation quantities free or almost free from any rigid body motion in a given displacement field. One of advantage of the co-rotational approach is the fact that linear models can be easily used in the local coordinate system for modeling of nonlinear problems. The geometric non-linearity is incorporated in the transformation matrices relating local and global internal force vectors and tangent stiffness matrices. Three different numerical examples are studied using this approach. Results demonstrate that the deformations of tensegrity system are dependent on the value of pre-stress in tensegrity systems. The displacements of tensegrity system are decreased for fixed external tensile loading and increasing pre-tension force, however, for fixed pre-tension force and increasing external loading the displacements of tensegrity system are increased.

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In recent years, rubber pad forming process have many advantages, such as high flexibility, good surface quality and lower manufacturing costs; RPF have been widely used in automotive, aerospace and military industries. In present research, numerical and experimental analysis of free bulging 304 stainless steel seamed tube, using a polyurethane elastic pad has been studied. Firstly, 3D simulation of seamed tube bulging using the finite element ABAQUS/Explicit 6.12 software by several frictional conditions has been performed. An incompressible hyperelastic pad has been modeled by Mooney-Rivlin constitutive equation and the elastic-plastic behavior as more as progressive ductile damage criterion FLD for steel tube were assumed. In the experimental activity, compression test of rubber was carried out according to ASTM D575-91 standard and compressive stress-strain curve and the Mooney-Rivlin constants were determined. Forming of meshed tubes by using elastic pad with different lubricating systems have been conducted up to onset of bursting in the seam weld and longitudinal, hoop and thickness strains were measured. Results showed that friction, especially between rubber and tube plays the main role in controlling wrinkles, increasing the bulge depth, reducing the forming load and friction dissipation energy of the process. Also observed that the intact parts without any wrinkles formed by using nylon lubricant between tube and rubber and drawing oil between tubes and die.

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Bulging with elastomer tool has been used in the production of integrated hollow parts as one of flexible forming methods. Nowadays, most industries such as Aerospace and military are using flexible die forming methods due to their flexibility, high quality and lower cost. In this research, finite element simulation has been implemented by ABAQUS software to investigate the behavior of stainless steel 304 tube bulging process using elastomer tool. By comparing the geometry of deformed tubes in experimental tests and simulation results, the FEM model was verified. The aim of this study is to determine the process factors and their effects on the average thickness and depth of bulged tube. In this regard, design of experiment (DOE) was performed using a full factorial method and the results were interpreted using analysis of variance (ANOVA). Also a regression model was presented to predict these responses. Results showed that among the studied factors, friction (between tube and rubber), rubber height, punch displacement and tube axial feeding have significant effects on the process. Finally, the optimal values for significant factors were presented.

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The ECAP-Conform is one of the newest and less known processes that improve mechanical properties. In the present study, the effective parameters of the ECAP-Conform process for AA7075 have been investigated. Influence of parameters such as roller radius, bending angle, die channel angles, rod/roll friction coefficient, rod/die friction coefficient, and the aspect ratio of the die groove on the torque, the applied force on the die, the stress, and the effective plastic strain, the output rod curvature, and the strain distribution uniformity have been investigated. The design of experiments was carried out based on the response surface method by the Minitab software, and simulations were performed using the ABAQUS software. To validate the FEM, the ECAP-Conform process of AA7075 rod was performed and the comparison of experimental and numerical results have acceptable compliance (7.5% error). It was found that the die channel angles and the rod/die friction coefficient have a more significant effect on all responses. Moreover, to maximize the imposed strain and strength, and to minimize the process torque and curvature, as well as achieving a uniform distribution of strain, the optimal output parameters have been obtained.