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Additive manufacturing technology significantly simplifies the production of complex three-dimensional (3 D) parts directly from the computer-aided design (CAD) model. Although additive manufacturing (AM) processes have unexampled flexibility, they still have restrictions inhibiting engineers to easily generate some specific geometric shapes, easily. Some of these problems pertain to the consumption of materials as supports, the inferior surface finish of some surfaces with certain angles, etc. One of the approaches to overcome these problems is designing by segmentation.

The proposed methodology consists of two steps: (1) segmentation of the 3 D model and (2) exploring the best orientation for each segment. In the first step, engineers consider the possible number of segments and the connection method of segments. In this paper, a series of segments, called a segmentation pattern (SP), is obtained by the recognition of features and separating them automatically (or manually when needed) with one or more appropriate planes. In the second step, the best fabrication orientation should be chosen. The criteria for choosing the best SP and OPs are minimizing the support volume, building time (directly affected by segments’ height in layer-wise AM processes) and surface roughness. Both steps are performed automatically (or manually when needed) by the algorithm created based on principles of particle swarm optimization (PSO) algorithm using Visual C#.

Experimental tests show that the segmentation design improves AM processes from the aspects of building time, material consumption and the surface quality. Segmentation design empowers users of AM technologies to reduce consumption of material by decreasing the support structures, to decrease the time of building by lowering the segments height and to decrease the surface roughness.

This paper presents an original approach in efficiency improvement of AM technologies, thus bringing the AM one step closer to maturity.

Stereolithography (SLA) is a broadly used technology in the field of rapid prototyping. One of the disadvantages of SLA is poor mechanical properties of its products. To approach the mechanical properties of original part, the mechanical properties of SLA part, such as tensile strength, should be optimized. In this process, there are many parameters that affect the tensile strength of parts. However, the “layer thickness”, “fabrication orientation” and “post curing time” are the most significant ones. Hence, the purpose of this study is to investigate the influence of these parameters on tensile strength of SLA parts.

According to the obtained results from experiments based on the “full factorial” method, an empirical equation was developed for the tensile strength in terms of the effective parameters by using regression analysis. Considering this empirical equation, the process parameters were optimized to maximize the tensile strength by using genetic algorithm. Finally, the tensile tests of the specimens were simulated via the general-purpose finite element package of ABAQUS.

The outputs of the numerical simulations were in good agreement with experimental results. Both experimental and numerical results show that the increase of layer thickness and the decrease in post curing time increase the tensile strength. Furthermore, the tensile strength of parts produced in vertical orientation is higher than that of parts produced in horizontal orientation.

This is a complete study about the tensile strength of the SLA parts from experimental and analytical viewpoints.

Drawing upon the social exchange theory and empowerment theory, the purpose of this paper is to investigate the effect of perceived person-environment fit on organisational citizenship behaviour (OCB). Furthermore, this study assesses the roles of organisational commitment and psychological empowerment (PE) in this relationship.

Respondents of this study were employees of the Iran Northeast Gas Transfer Company. Data were collected through conducting a survey on 500 employees, of which 412 questionnaires were used for further analysis. Confirmatory factor analysis, structural equation modelling, Baron and Kenny's (1986) procedure for examining mediator effect, and finally Zhao and Cavusgil's (2006) technique of evaluating moderator effect were utilised for the analyses.

Results indicated that organisational commitment acts as a mediator between person-job (P-J) fit and person-organisation (P-O) fit and OCB. PE acts as a moderator between organisational commitment and OCB.

This research has implications for approaches to human resource management in organisations.

This study empirically synthesises the joint effect of P-O fit and P-J fit on a behavioural variable (OCB) in the social context of organisation and explains the mechanism of the effect. The pattern of relationships tested is relatively novel.

The purpose of this paper is to identify the librarians’ quality of working life (QWL) in the Iranian public libraries.

The present study is an applied research in terms of purpose and an analytical survey in terms of data collection and analysis method. The Walton standard questionnaire was used as the data collection tool. The statistical population of this research consists of librarians in the Iranian public libraries. Descriptive and inferential statistics were used in order to analyze the data.

The findings showed that the dimensions of organizational social integration, constitutionalism in the organization and the capacity for human development are at a good level; the dimensions of the environment opportunity for continued growth and security and safe and healthy work are at a moderate level. Finally, the dimensions of fair and adequate payment, social relevance of work life and total life space are at a weak level are shown.

The findings of the confirmed hypothesis indicated that the librarians at the Iranian public libraries have a desirable (high) QWL.

The present study seeks to design an index model of satisfaction among Iranian students who are studying at public universities in this country.

In this research, data were collected in two stages: in the first stage, the data related to satisfaction indices were collected from 62 experts on pedagogical science and marketing management. In the second step, the data were collected from 1,404 students and were analysed by fuzzy analytic hierarchical process method, interpretive structural modelling and structural equation modelling.

The results of this study showed that three variables “perceived quality”, “organization image” and “Student relationship management” are reliable as indicators of student satisfaction. Also, contrary to the results of previous studies, the variable of expectations cannot predict the satisfaction of the students.

Models of satisfaction have been designed in different fields. Also, in the measurement of satisfaction, attention to the field and customization is approved by researchers. Accordingly, the present study tries to design indices of satisfaction among students of state universities in Iran. It also pointed out the effect of customization on the formation of satisfaction at the Iranian and other universities.

This paper empirically examines whether sophisticated governance mechanism affects the relationship between earnings management and dividend policy of non-financial firms.

The sample of the study includes non-financial firms listed on the stock exchanges of twenty developed and developing economies from the period 2005–2017. The Generalized Method of Moments (GMM) was applied to estimate the econometric models.

The results confirm the positive association between earning management and the dividend payout ratio of the sample firms. These findings are in line with the signaling theory, which suggests that firms engage in earnings manipulation to signal to the market that they can maintain a smooth dividend distribution. Moreover, findings suggest that board independence, being a mechanism of corporate governance, significantly negatively moderated the relationship between earnings management and the dividend payout ratio of non-financial firms.

The findings provide valuable suggestions to government bodies, regulatory authorities and corporate managers to focus on the effectiveness of governance mechanisms to improve the reliability of financial reports.

These findings imply that the effect of earning management on the dividend payout ratio is less pronounced in firms with more independent directors on the company board.

The purpose of the current study is to investigate the public and private financing obstacles to medium- and small-scale entrepreneurs in rural areas in Iran.

Descriptive analytic research method is used for collecting field data among 5,770 owners of entrepreneurial businesses located in rural areas of Mashhad in 2015.

The results showed that there are numerous public and private obstacles in rural entrepreneurship financing in Iran, which are the main factors for short-term loan repayment in public sector, and in the private sector, they result in entrepreneurs’ lack of access to the source of financing. Moreover, there are a variety of financing methods for entrepreneurship in rural areas, among which personal resources and borrowings are the most important ones. Thus, lack of serious and persistent governmental support from local entrepreneurs causes many entrepreneurial failures at the early stages of entrepreneurial activity in villages of Iran.

So far, few studies have been conducted on the subject of the study; hence, the results of the current study may be helpful to the developing nations.

This paper aims to investigate the relationship between a CEO's ability and authority with firm performance. The authors used a sample of 127 Iranian listed firms for over seven years, from 2011 to 2017.

The authors used data envelopment analysis (DEA) to evaluate managers' abilities, and the authors used business strategies to gauge authorities. Also, the methods of Fama–French and Herfindal–Hirschman were used for 889 firm-year observations.

The results show that managers' ability based on return on assets can affect firm performance, and skilled managers can improve performance.

In Iran, managers' abilities and other variables can impact it has been studied. Still, no study has been conducted on managers' strength and their level of authority with the presence of supervision on them.

This study aims to use gray models to predict abnormal stock returns.

Data are collected from listed companies in the Tehran Stock Exchange during 2005-2015. The analyses portray three models, namely, the gray model, the nonlinear gray Bernoulli model and the Nash nonlinear gray Bernoulli model.

Results show that the Nash nonlinear gray Bernoulli model can predict abnormal stock returns that are defined by conditions other than gray models which predict increases, and then after checking regression models, the Bernoulli regression model is defined, which gives higher accuracy and fewer errors than the other two models.

The stock market is one of the most important markets, which is influenced by several factors. Thus, accurate and reliable techniques are necessary to help investors and consumers find detailed and exact ways to predict the stock market.