Gangxian Zhu, Dichen Li, Anfeng Zhang, Gang Pi and Yiping Tang
The purpose of this paper is to investigate the influencing rule of the standoff distance variations between the nozzle outlet and the powder deposition point on forming…
Abstract
Purpose
The purpose of this paper is to investigate the influencing rule of the standoff distance variations between the nozzle outlet and the powder deposition point on forming dimensional accuracy.
Design/methodology/approach
The thin‐wall parts were built with three different standoff distances: 1 mm more than the powder focus length, equal to the powder focus length and 1 mm less than the powder focus length. Based on the experimental results, the steady standoff distance can be acquired and the difference between the building height and the ideal height of thin‐wall parts can be compensated automatically in several layers by theoretical calculation.
Findings
The experimental results show that the top surface unevenness of thin‐wall parts can be compensated automatically on the consequent successive layers when the standoff distance is less than the powder focal length from the nozzle outlet to the powder focal point, and the poorer results are obtained when the standoff distance is equal to or more than the powder focal length in the deposition of stainless steel 316L under open‐loop control.
Practical implications
The shape of parts affects the self‐regulation effect in practical applications, so the self‐regulation effect is useful when the single contour of parts is continuous straight faces and the surface of parts is perpendicular to the build platform, and will be useless for parts with holes.
Originality/value
According to the requirements under different process conditions in practical applications, one should first find out the relationship between the standoff distance and the building height of single‐trace cladding layer, and then use regression algorithm to obtain the stable standoff distance by simple theoretical calculation. The uniform building height, layer thickness and smooth surface can be obtained at the stable standoff distance under open‐loop control.
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Bin He, Dichen Li, Anfeng Zhang, Zhongliang Lu, Jiangbo Ge and Doan Tat Khoa
The purpose of this paper is to investigate the influence of the oxidation on the cracks of DZ125L nickel-based superalloy thin-walled parts in laser metal direct forming (LMDF)…
Abstract
Purpose
The purpose of this paper is to investigate the influence of the oxidation on the cracks of DZ125L nickel-based superalloy thin-walled parts in laser metal direct forming (LMDF).
Design/methodology/approach
Thin-walled cylinders were fabricated in protective atmosphere with different oxygen contents in order to reveal the influence of oxidation on the morphology of cracks. The influence of oxidation on the cracks was investigated in detail by measuring the wall thicknesses of cylinders, the residual stress in the top surface of the cylinders and the composition of the cracks. Finally, the validity of the results was verified by fabricating a thin-walled turbine blade in protective atmosphere.
Findings
The experimental results showed that wall thickness fluctuation of cylinders, unequal residual stress distribution of cylinders and the oxides in the crack were all the critical factors which led to crack of DZ125L thin-walled parts. Thin-walled turbine blades with no cracks can be fabricated when the oxygen content was about less than 150 ppm in protective atmosphere.
Research limitations/implications
The appropriate oxygen content in protective atmosphere is helpful for fabricating thin-walled parts of nickel-based superalloy like DZ125L, and the results can show what will happen at different oxygen levels. Moreover, the results show that the cracks can be eliminated as the oxygen content reduce to less than 150 ppm rather less than 10 ppm or even less, which can reduce the cost of protective gas as forming thin-walled parts of nickel-based superalloy such as DZ125L.
Practical implications
The appropriate oxygen content in protective atmosphere is helpful for fabricating thin-walled parts of nickel-based superalloy like DZ125L. However, when heavy solid parts of some other material other than DZ125L were fabricated, the oxygen content of less than 150 ppm may be not suitable.
Originality/value
The influence of oxidation on the cracks of DZ125L thin-walled parts in LMDF was investigated in detail, and a DZ125L thin-walled turbine blade with no cracks was fabricated by adjusting the oxygen content in protective atmosphere.
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This meta-analysis reviews and summarizes the results of 34 studies to investigate the relationship between overconfidence and financial decision-making.
Abstract
Purpose
This meta-analysis reviews and summarizes the results of 34 studies to investigate the relationship between overconfidence and financial decision-making.
Design/methodology/approach
A correlation meta-analysis was conducted with three moderators of the relationship between overconfidence and financial decision-making examined: the type of overconfidence construct, the type of overconfidence measuring method and the type of financial decision-making.
Findings
It was found that the effect of overconfidence on financial decision-making was significant, but the magnitude of this effect was low. Additionally, indirect measures of overconfidence showed to have stronger effect than direct measures, and the overconfidence was mostly related to investment, followed by trading and innovativeness.
Originality/value
This was the first attempt to meta-analytically integrate results concerning the relationship between overconfidence and financial decision-making. Although overconfidence is described as a keystone for understanding financial decision-making, it was shown that it has rather limited effect on individuals' financial decisions. The findings suggest that indirect measures increase the overall effect and may cause the overvaluation of overconfidence in literature. The results call for more rigorous and consistent conceptualization of overconfidence in behavioral research.
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Moses Munyami Kinatta, Twaha Kigongo Kaawaase, John C. Munene, Isaac Nkote and Stephen Korutaro Nkundabanyanga
This study examines the relationship between investor cognitive bias, investor intuitive attributes and investment decision quality in commercial real estate in Uganda.
Abstract
Purpose
This study examines the relationship between investor cognitive bias, investor intuitive attributes and investment decision quality in commercial real estate in Uganda.
Design/methodology/approach
A cross-sectional research survey was used in this study, and data were collected from 200 investors of commercial real estate in Uganda using a structured questionnaire. Hierarchical regression analysis was used to test the hypotheses derived under this study.
Findings
The results indicate that investor cognitive bias and investor intuitive attributes are positive and significant determinants of investment decision quality in commercial real estate. In addition, the two components of Investor cognitive bias (framing variation and cognitive heuristics) are positive and significant determinants of investment decision quality, whereas mental accounting is a negative and significant determinant of investment decision quality. For investor intuitive attributes, confidence degree and loss aversion are positive and significant determinants of investment decision quality, whereas herding behavior is a negative and significant determinant of investment decision quality in commercial real estate in Uganda.
Practical implications
For practitioners in commercial real estate sector should emphasize independent evaluation of investment opportunities (framing variation), simplify information regarding investments (Cognitive heuristics), believe in own abilities (Confidence degree), be risk averse (loss aversion) and avoid making decisions based on subjective visual mind (mental accounting) and group think/herding in order to make quality investment decisions. For policymakers, the study has illuminated factors such as provision of reliable information that ought to be taken into account when promulgating policies for regulation of the commercial real estate sector. This will help investors to come up with investment decisions which are plausible.
Originality/value
Few studies have focused on investor cognitive bias and investor intuitive attributes on investment decision quality in commercial real estate. This study is the first to examine the relationship, especially in the commercial real estate sector in a developing country like Uganda.
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This paper aims to make a comprehensive evaluation of the progress and achievements made by China and Japan in literature collection, publication and academic research of South…
Abstract
Purpose
This paper aims to make a comprehensive evaluation of the progress and achievements made by China and Japan in literature collection, publication and academic research of South Manchuria Railways Co (SMR) after the Second World War and points out the existing and urgent problems.
Design/methodology/approach
This paper adopts the methods of literature research, questionnaire survey, comparative analysis and expert consultation.
Findings
After the Second World War, both China and Japan made great achievements in the collection, publication and research of SMR data, as well as in the academic research of SMR. However, as a new research field, there are still some problems in deepening the excavation and utilization of SMR data, expanding the research fields, improving the research methods, etc.
Originality/value
SMR itself was the product of a war of aggression. Although it died with the defeat of the war of aggression, remaining SMR data also has very precious value, it records the history of Japanese aggression against China, is the biggest database for the study of the problems in China and northeast Aisa at that time. In addition to Japan and China, the USA and the Soviet Union also kept part of the SMR data, so that to involve them in the research of SMR is also the purpose of this paper.
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Osama El-Ansary and Aya M. Ahmed
This paper aims to investigate whether managerial overconfidence has an impact on investment inefficiency beyond its influence on the use of internal financing or whether internal…
Abstract
Purpose
This paper aims to investigate whether managerial overconfidence has an impact on investment inefficiency beyond its influence on the use of internal financing or whether internal financing behaves as a full intermediary.
Design/methodology/approach
The study employed three dependent variables, namely business investment scale, overinvestment and underinvestment, and analyzed data from 282 firms across five different industries listed in 11 Middle East/North Africa (MENA) countries between 2013 and 2019 using regression analysis via least square dummy variable (LSDV).
Findings
The findings indicate that while internal financing can provide funding for investment opportunities and address capital shortages, it may also result in overinvestment, particularly in companies led by overconfident managers.
Practical implications
Stakeholders, including shareholders and board of directors, should pay attention to the chief executive officer (CEO)'s behavioral aspects such as overconfidence in decision-making while undertaking new investment projects. Additionally, regulators and policymakers in emerging markets like MENA should re-evaluate the corporate governance framework, devise a corporate governance index and promote boardroom gender diversity as it can significantly reduce risk.
Originality/value
This study adds to the limited research on the impact of managerial overconfidence on investment efficiency in the MENA region. By focusing on this region, which has unique economic, political and social characteristics, the study provides new insights into the role of behavioral biases in investment decision-making in emerging markets.