During the last decades, metal additive manufacturing (AM) technology has transitioned from rapid... more During the last decades, metal additive manufacturing (AM) technology has transitioned from rapid prototyping application to industrial adoption owing to its flexibility in product design, tooling, and process planning. Thus, understanding the behavior, interaction, and influence of the involved processing parameters on the overall AM production system in order to obtain high-quality parts and stabilized manufacturing process is crucial. Despite many advantages of the AM technologies, difficulties arise due to modelling the complex nature of the process-structure-property relations, which prevents its wide utilization in various industrial sectors. It is known that many of the most important defects in direct energy deposition (DED) are associated with the volume and timescales of the evolving melt pool. Thus, the development of methodologies for monitoring, and controlling the melt pool is critical. In this study, an adaptive numerical transient solution is developed, which is fed ...
The International Journal of Advanced Manufacturing Technology
Manufacturing processes, such as machining, can produce residual stresses in products. Residual s... more Manufacturing processes, such as machining, can produce residual stresses in products. Residual stress and its distribution can be the main factor influencing the fatigue life of machined components and has already been the subject of many experimental and numerical studies. The high-temperature condition, as a result of machining, makes a change in the microstructural properties of the material and consequently affect the mechanical properties of the workpiece. A major metal component of aircraft structure and engine components is nickel-based alloys due to their resistance to heat, corrosion, thermal fatigue, thermal shock, creep, and erosion. When these critical structural components in the aerospace industry are manufactured with the objective to reach high-reliability levels, surface integrity is one of the most relevant parameters used for evaluating the quality of finish-machined surfaces. The residual stresses and surface alterations including white layer, depth of work hard...
Corporate directors are influenced by overconfidence, which is one of the personality traits of i... more Corporate directors are influenced by overconfidence, which is one of the personality traits of individuals; it may take irrational decisions that will have a significant impact on the company's performance in the long run. The purpose of this paper is to validate and compare the Naive Bayesian Classification algorithm and probit regression in the prediction of Management's overconfident at present and in the future. Financial during the years are 2012 to 2017. To support the theoretical results, the samples were the companies admitted to the Tehran Stock Exchange, (financial data of 1292 companies/year in total). Data collection in the theoretical part of the study benefitted from the library method, and for calculating data, Excel software was used, and in order to test the research hypotheses Matlab 2017 and Eviews10.0 were used. The empirical findings demonstrate that, Gained nonlinear prediction model of the Naive Bayes Classification algorithm, has high ability to predi...
In this study, effect of managers incentive for profitability on stickiness of operating costs at... more In this study, effect of managers incentive for profitability on stickiness of operating costs at large and small companies admitted in Tehran Stock Exchange during years 2008-2013 have been investigated. In total, there were 612 observations available in this research among which 302 observations were related to large companies and 310 cases were related to small companies. The statistical method used in this research was multivariate regression method. Results obtained from research hypotheses indicate that when managers make decisions with incentive for enhancing profitability, they emphasize on reducing stickiness of operating costs at large and small companies.
Journal of Dentistry, Shiraz University of Medical Sciences, 2006
Statement of Problem: Porosity is a frequently observed casting defect in titanium dental casting... more Statement of Problem: Porosity is a frequently observed casting defect in titanium dental casting. Purpose : This study measured the effects of different sprue design on the internal porosity of cast titanium crowns. Materials and Method : Sixty complete veneer crowns were fabricated on a stainless steel die with a 150- degree sloping shoulder using customized wax patterns. All wax patterns were sprued with 3 different sprue design (Reservoir, Runner bar and Rousseau) and were invested with an alumina- magnesia investment. Castings were made with commercially pure titanium (CP Ti (grade II)) according to the manufacturer's instructions. The castings were carefully cleaned. Internal porosities were quantified with photographs and radiographs by computerized image analyses. Data were analyzed with an ANOVA with a confidence level of 95%. Results: There were statistically significant differences in the values of porosity between 3 types of sprue design. The reservoir sprue design ...
The aim of the study " The Different Role of Mental Accounting on Optimal Portfolio Based on... more The aim of the study " The Different Role of Mental Accounting on Optimal Portfolio Based on Speculative Bubble on companies listed in the Tehran Stock Exchange" is the 10-year study period listed in the Tehran Stock Exchange during 2008-2017 were analyzed.The data of 110 firms were analyzed by using statistical softwares including Matlab, spss20, Eviews7 and Lingo in the studied years. In this research, mental accounting is based on Fernandez (2009), The speculative bubble based on the gilium pattern (2016) are used as a risk measurement indicator. The result of testing the above hypotheses showed that for the calculated returns because it is greater than the error level, the hypothesis of equality of the average returns of the portfolios is not rejected. In terms of speculation bubble (subject to speculation) based on subjective accounting there is no significant difference and efficiency based on standard deviation index is not higher. The result of the statistical test...
During the last decades, metal additive manufacturing (AM) technology has transitioned from rapid... more During the last decades, metal additive manufacturing (AM) technology has transitioned from rapid prototyping application to industrial adoption owing to its flexibility in product design, tooling, and process planning. Thus, understanding the behavior, interaction, and influence of the involved processing parameters on the overall AM production system in order to obtain high-quality parts and stabilized manufacturing process is crucial. Despite many advantages of the AM technologies, difficulties arise due to modelling the complex nature of the process-structure-property relations, which prevents its wide utilization in various industrial sectors. It is known that many of the most important defects in direct energy deposition (DED) are associated with the volume and timescales of the evolving melt pool. Thus, the development of methodologies for monitoring, and controlling the melt pool is critical. In this study, an adaptive numerical transient solution is developed, which is fed ...
The International Journal of Advanced Manufacturing Technology
Manufacturing processes, such as machining, can produce residual stresses in products. Residual s... more Manufacturing processes, such as machining, can produce residual stresses in products. Residual stress and its distribution can be the main factor influencing the fatigue life of machined components and has already been the subject of many experimental and numerical studies. The high-temperature condition, as a result of machining, makes a change in the microstructural properties of the material and consequently affect the mechanical properties of the workpiece. A major metal component of aircraft structure and engine components is nickel-based alloys due to their resistance to heat, corrosion, thermal fatigue, thermal shock, creep, and erosion. When these critical structural components in the aerospace industry are manufactured with the objective to reach high-reliability levels, surface integrity is one of the most relevant parameters used for evaluating the quality of finish-machined surfaces. The residual stresses and surface alterations including white layer, depth of work hard...
Corporate directors are influenced by overconfidence, which is one of the personality traits of i... more Corporate directors are influenced by overconfidence, which is one of the personality traits of individuals; it may take irrational decisions that will have a significant impact on the company's performance in the long run. The purpose of this paper is to validate and compare the Naive Bayesian Classification algorithm and probit regression in the prediction of Management's overconfident at present and in the future. Financial during the years are 2012 to 2017. To support the theoretical results, the samples were the companies admitted to the Tehran Stock Exchange, (financial data of 1292 companies/year in total). Data collection in the theoretical part of the study benefitted from the library method, and for calculating data, Excel software was used, and in order to test the research hypotheses Matlab 2017 and Eviews10.0 were used. The empirical findings demonstrate that, Gained nonlinear prediction model of the Naive Bayes Classification algorithm, has high ability to predi...
In this study, effect of managers incentive for profitability on stickiness of operating costs at... more In this study, effect of managers incentive for profitability on stickiness of operating costs at large and small companies admitted in Tehran Stock Exchange during years 2008-2013 have been investigated. In total, there were 612 observations available in this research among which 302 observations were related to large companies and 310 cases were related to small companies. The statistical method used in this research was multivariate regression method. Results obtained from research hypotheses indicate that when managers make decisions with incentive for enhancing profitability, they emphasize on reducing stickiness of operating costs at large and small companies.
Journal of Dentistry, Shiraz University of Medical Sciences, 2006
Statement of Problem: Porosity is a frequently observed casting defect in titanium dental casting... more Statement of Problem: Porosity is a frequently observed casting defect in titanium dental casting. Purpose : This study measured the effects of different sprue design on the internal porosity of cast titanium crowns. Materials and Method : Sixty complete veneer crowns were fabricated on a stainless steel die with a 150- degree sloping shoulder using customized wax patterns. All wax patterns were sprued with 3 different sprue design (Reservoir, Runner bar and Rousseau) and were invested with an alumina- magnesia investment. Castings were made with commercially pure titanium (CP Ti (grade II)) according to the manufacturer's instructions. The castings were carefully cleaned. Internal porosities were quantified with photographs and radiographs by computerized image analyses. Data were analyzed with an ANOVA with a confidence level of 95%. Results: There were statistically significant differences in the values of porosity between 3 types of sprue design. The reservoir sprue design ...
The aim of the study " The Different Role of Mental Accounting on Optimal Portfolio Based on... more The aim of the study " The Different Role of Mental Accounting on Optimal Portfolio Based on Speculative Bubble on companies listed in the Tehran Stock Exchange" is the 10-year study period listed in the Tehran Stock Exchange during 2008-2017 were analyzed.The data of 110 firms were analyzed by using statistical softwares including Matlab, spss20, Eviews7 and Lingo in the studied years. In this research, mental accounting is based on Fernandez (2009), The speculative bubble based on the gilium pattern (2016) are used as a risk measurement indicator. The result of testing the above hypotheses showed that for the calculated returns because it is greater than the error level, the hypothesis of equality of the average returns of the portfolios is not rejected. In terms of speculation bubble (subject to speculation) based on subjective accounting there is no significant difference and efficiency based on standard deviation index is not higher. The result of the statistical test...
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