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Article
Publication date: 28 March 2023

Minting Wang, Renjie Cao, HuiChao Chang and Dong Liang

Laser-based powder bed fusion (LPBF) is a new method for forming thin-walled parts, but large cooling rates and temperature gradients can lead to large residual stresses and…

Abstract

Purpose

Laser-based powder bed fusion (LPBF) is a new method for forming thin-walled parts, but large cooling rates and temperature gradients can lead to large residual stresses and deformations in the part. This study aims to reduce the residual stress and deformation of thin-walled parts by a specific laser rescanning strategy.

Design/methodology/approach

A three-dimensional transient finite element model is established to numerically simulate the LPBF forming process of multilayer and multitrack thin-walled parts. By changing the defocus amount, the laser in situ annealing process is designed, and the optimal rescanning parameters are obtained, which are verified by experiments.

Findings

The results show that the annealing effect is related to the average surface temperature and scan time. When the laser power is 30 W and the scanning speed is 20 mm/s, the overall residual stress and deformation of the thin-walled parts are the smallest, and the in situ annealing effect is the best. When the annealing frequency is reduced to once every three layers, the total annealing time can be reduced by more than 60%.

Originality/value

The research results can help better understand the influence mechanism of laser in situ annealing process on residual stress and deformation in LPBF and provide guidance for reducing residual stress and deformation of LPBF thin-walled parts.

Article
Publication date: 7 July 2022

Wenshin Chen

This study seeks to explore digital natives' mobile usage behaviors and, in turn, develop an analytic framework that helps articulate the underlying components of mobile addiction…

Abstract

Purpose

This study seeks to explore digital natives' mobile usage behaviors and, in turn, develop an analytic framework that helps articulate the underlying components of mobile addiction syndrome (MAS), its severity levels and mobile usage purposes.

Design/methodology/approach

The investigation adopts a survey method and a case study. The results of the former are based on 411 random classroom observations and 205 questionnaire responses, and the insights of the latter are derived from 24 interviews and daily observations.

Findings

The findings validate five distinctive signs that constitute MAS and their significant correlations with each of the Big Five personality traits. Classroom observations confirm the prevalence of addiction tendency among digital natives in the research context. Seven levels of MAS and six different mobile usage purposes further manifest themselves from case analysis. There appears to be a sharp contrast between the addicted and non-addicted groups in their mobile purposes and behavioral patterns. Additionally, family relationships seem influential in shaping non-addictive mobile usage behaviors.

Research limitations/implications

Psychological perspectives on MAS may be important but insufficient. Empirical investigation on a global scale, especially with distinctive cross-cultural comparisons, will be highly encouraged. How MAS evolves over time should also serve as future research interests.

Practical implications

Teaching pedagogy of college education might need certain adjustments to intrigue digital natives' learning interests. Future managers might also need to adopt better performance measurements for digital natives who barely separate work from personal matters in their mobile devices.

Social implications

Parents and healthcare institutions may need to develop response mechanism to tackle this global issue at home and in society. The long-term effects of the COVID-19 pandemic on MAS might also deserve global attention.

Originality/value

The analytic framework developed provides an original mechanism that can be valuable in identifying MAS severity and associated behavioral patterns.

Details

Information Technology & People, vol. 36 no. 3
Type: Research Article
ISSN: 0959-3845

Keywords

Article
Publication date: 1 February 2024

Sandeep Kaur, Harpreet Singh, Devesh Roy and Hardeep Singh

Despite the susceptibility of cotton crops to pest attacks in the Malwa Region of Indian Punjab, no crop insurance policy has been implemented there– not even the Pradhan Mantri…

Abstract

Purpose

Despite the susceptibility of cotton crops to pest attacks in the Malwa Region of Indian Punjab, no crop insurance policy has been implemented there– not even the Pradhan Mantri Fasal Bima Yojana (PMFBY), which is a central scheme. Therefore, this paper attempts to gauge the likely impact of the PMFBY on Punjab cotton farmers and assess the changes needed for greater uptake and effectiveness of PMFBY.

Design/methodology/approach

The authors have conducted a primary survey to conduct this study. Initially, the authors compared the costs of cotton production with the returns in two scenarios (with and without insurance). Additionally, the authors have applied a logistic regression framework to examine the determinants of the willingness of farmers to participate in the crop insurance market.

Findings

The study finds that net returns of cotton crops are conventionally small and insufficient to cope with damages from crop failure. Yet, PMFBY will require some modifications in the premium rate and the level of indemnity for its greater uptake among Punjab cotton farmers. Additionally, using the logistic regression framework, the authors find that an increase in awareness about crop insurance and farmers' perceptions about their crop failure in the near future reduces the willingness of the farmers to participate in the crop insurance markets.

Research limitations/implications

The present study looks for the viability of PMFBY in Indian Punjab for the cotton crop, which can also be extended to other crops.

Social implications

Punjab could also use crop insurance to encourage diversification in agriculture. There is a need for special packages for diversified crops under any crop insurance policy. Crops susceptible to volatility due to climate-related factors should be identified and provided with a special insurance package.

Originality/value

There exist very scant studies that have discussed the viability of a central crop insurance scheme in the agricultural-rich state of India, i.e. Punjab. Moreover, they do not also focus on crop losses accruing due to pest and insect attacks.

Details

Journal of Agribusiness in Developing and Emerging Economies, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 2044-0839

Keywords

Article
Publication date: 11 January 2024

Mohd Syahidan Zainal Abidin, Mahani Mokhtar and Mahyuddin Arsat

Education for sustainable development (ESD) has gained significant attention, but integrating ESD into existing education systems is challenging. The study aims to explore the…

Abstract

Purpose

Education for sustainable development (ESD) has gained significant attention, but integrating ESD into existing education systems is challenging. The study aims to explore the challenges of ESD experienced by school leaders, focusing on the context of Malaysian schools.

Design/methodology/approach

The study uses a qualitative approach with a single-case study design. Eight school leaders involved in the Johor sustainable education action plan (JSEAP) were interviewed and analyzed. The study uses thematic analysis to identify the challenges and other causes associated with the implementation of ESD.

Findings

This study revealed that the school leaders perceived the ESD challenges at three levels. First, restriction to the standardized curriculum (systemic); second, resistance to change (organization) and third, awareness and readiness (individual). These themes stemmed from seven primary codes that school leaders encountered throughout the JSEAP program.

Research limitations/implications

This paper is limited to a case study of the chosen schools and cannot be extrapolated to a larger population.

Practical implications

The study benefits school leaders and educators concerned about ESD and its role in their schools and other academics interested in ESD.

Originality/value

To the authors' knowledge, this is the first study to investigate ESD challenges in Malaysia. The novel discovery of the three levels of ESD challenges helps readers better understand the recent phenomenon of ESD implementation and compare it to other settings.

Details

Qualitative Research Journal, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1443-9883

Keywords

Book part
Publication date: 24 April 2023

Han-Ying Liang, Yu Shen and Qiying Wang

Joon Y. Park is one of the pioneers in developing nonlinear cointegrating regression. Since his initial work with Phillips (Park & Phillips, 2001) in the area, the past two…

Abstract

Joon Y. Park is one of the pioneers in developing nonlinear cointegrating regression. Since his initial work with Phillips (Park & Phillips, 2001) in the area, the past two decades have witnessed a surge of interest in modeling nonlinear nonstationarity in macroeconomic and financial time series, including parametric, nonparametric and semiparametric specifications of such models. These developments have provided a framework of econometric estimation and inference for a wide class of nonlinear, nonstationary relationships. In honor of Joon Y. Park, this chapter contributes to this area by exploring nonparametric estimation of functional-coefficient cointegrating regression models where the structural equation errors are serially dependent and the regressor is endogenous. The self-normalized local kernel and local linear estimators are shown to be asymptotic normal and to be pivotal upon an estimation of co-variances. Our new results improve those of Cai et al. (2009) and open up inference by conventional nonparametric method to a wide class of potentially nonlinear cointegrated relations.

Book part
Publication date: 5 April 2024

Emir Malikov, Shunan Zhao and Jingfang Zhang

There is growing empirical evidence that firm heterogeneity is technologically non-neutral. This chapter extends the Gandhi, Navarro, and Rivers (2020) proxy variable framework…

Abstract

There is growing empirical evidence that firm heterogeneity is technologically non-neutral. This chapter extends the Gandhi, Navarro, and Rivers (2020) proxy variable framework for structurally identifying production functions to a more general case when latent firm productivity is multi-dimensional, with both factor-neutral and (biased) factor-augmenting components. Unlike alternative methodologies, the proposed model can be identified under weaker data requirements, notably, without relying on the typically unavailable cross-sectional variation in input prices for instrumentation. When markets are perfectly competitive, point identification is achieved by leveraging the information contained in static optimality conditions, effectively adopting a system-of-equations approach. It is also shown how one can partially identify the non-neutral production technology in the traditional proxy variable framework when firms have market power.

Article
Publication date: 20 October 2023

Jyh-Bin Yang and Ying-Fu Chen

An S-curve is an essential project-management tool. However, it is difficult to adjust S-curve to deal with a force majeure event. The present study develops four valuable…

Abstract

Purpose

An S-curve is an essential project-management tool. However, it is difficult to adjust S-curve to deal with a force majeure event. The present study develops four valuable adjustment approaches, designed to achieve a compromise between the views of the client and contractor. These can be used to control projects after a force majeure event.

Design/methodology/approach

The present study develops four adjustment approaches, which can be used to achieve a compromise between the views of the client and those of the contractor when controlling projects after a force majeure. To determine the S-curves during a force majeure event, two approaches can be selected: BCWS (budgeted cost of scheduled work)-base approach, or BCWP (budgeted cost of work performed)-base approach. To determine the rest of S-curves after a force majeure event, two approaches can be considered: maintaining the original curve of the remaining BCWS, or allocating the original curve of the remaining BCWS. Based on the validation of three empirical cases, drawn from a professional project-management website, this study confirms the feasibility of four proposed empirical approaches and a selection procedure for S-curve adjustment.

Findings

The S-curve-adjustment approaches presented here can be used to deal with cases that are ahead of, on and behind schedule. Using the proposed approaches and selection procedure, contractors can easily revise S-curves and control projects more effectively. To deal with a force majeure event, such as COVID-19, they are strongly advised to adopt the approaches labeled SA-A1 (to adjust the S-curve based on the extension ratio multiplied by the difference in progress during the force majeure) and SA-B1 (to maintain the original curve of the remaining BCWS) for the A/E and E/F curves, respectively.

Research limitations/implications

The proposed approaches can be used in cases of continuous construction during force majeure events. If construction work is totally suspended during such an event, it will be necessary to fine-tune the proposed approaches.

Originality/value

Previous studies have used case-oriented or mathematical-simulation approaches to forecast S-curves. The present study proposes simple approaches that allow the client and contractor to adjust the S-curve easily after a force majeure event. These approaches can be used to adjust work and project-completion targets within an extended duration. Selecting the right S-curve adjustment approach can help to control the remainder of the project, reducing the possibility of delay claims.

Details

Engineering, Construction and Architectural Management, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0969-9988

Keywords

Article
Publication date: 22 March 2023

Ryuichi Kobayashi and Ming Yang

Orange peel formation remains to be understood clearly because it is difficult to directly observe a laser-sintered process in a partcake. Therefore, this study aims to provide…

Abstract

Purpose

Orange peel formation remains to be understood clearly because it is difficult to directly observe a laser-sintered process in a partcake. Therefore, this study aims to provide insight into the orange peel formation mechanism through the nondestructive observation of laser-sintered specimens and their surrounding powders.

Design/methodology/approach

This study observed polyamide 12 powder in the vicinity of a laser-sintered specimen via X-ray computed tomography (CT) scanning. The specimen for nondestructive observation was 3D modeled in a hollow box using 3D CAD software. The boxes built using a laser-sintering system contained unsintered surrounding powder and sintered specimens. The box contents were preserved even after the boxes were removed from the partcake. After X-ray CT scanning, the authors broke the boxes and evaluated the unevenness formed on the specimen surface (i.e. the orange peel evaluation).

Findings

Voids (not those in sintered parts) generated in the powder in the vicinity of the specimen triggered the orange peel formation. Voids were less likely to form in the build with a 178.5° powder bed than in the build with a 173.5° powder bed. Similarly, the increment in laser energy density effectively suppressed void formation, although there was a tradeoff with overmelting. Thin-walled parts avoided void growth and made the orange peel less noticeable.

Originality/value

To the best of the authors’ knowledge, this study is the first to observe and understand the relationship between voids generated in the powder in the vicinity of sintered parts and orange peel formation.

Details

Rapid Prototyping Journal, vol. 29 no. 7
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 28 June 2023

Liu Fuyu, Yu Bo, Li Yongfan, Ren Baojie, Hao Muming, Li Zhentao and Li Xiaozu

The purpose of this paper is to study the dynamic characteristics of mechanical face seals with liquid-lubricated inclined elliptical grooves.

Abstract

Purpose

The purpose of this paper is to study the dynamic characteristics of mechanical face seals with liquid-lubricated inclined elliptical grooves.

Design/methodology/approach

The steady-state and perturbation Reynolds control equations of liquid films were established. The film pressure and the liquid film dynamic coefficients were obtained, impacts of groove structures on the liquid film dynamic characteristic coefficients were analyzed.

Findings

The analysis results indicate that the axial dynamic stiffness and damping coefficients of the liquid film seal with inclined elliptical grooves are far greater than those of the angular directions. Furthermore, the dynamic stiffness coefficient of the liquid film with the nonclosed inclined elliptical grooves is higher than those with the closed grooves, whereas the dynamic damping coefficient of the liquid film is lower.

Originality/value

The effects of inclined elliptical groove structures on the dynamic characteristics of the liquid film seal are investigated. The results presented are expected to enrich the theoretical basis of optimizing the dynamic performance of liquid film seals with textures.

Details

Industrial Lubrication and Tribology, vol. 75 no. 6
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 28 March 2023

Christopher A. Cooper

For many, the claim that a new approach to bureaucracy—new political governance (NPG)—is underway reads as if it was written by Stephen King: Frightening fiction. While the…

Abstract

Purpose

For many, the claim that a new approach to bureaucracy—new political governance (NPG)—is underway reads as if it was written by Stephen King: Frightening fiction. While the thought of promiscuously partisan senior public servants publicly defending and promoting the government’s reputation to the demise of impartiality is disturbing, the evidentiary record has led most to dismiss the idea as empirically false. This article questions, and empirically investigates, whether dismissing the idea of promiscuous partisanship has been premature.

Design/methodology/approach

A case study of the loyalty displayed by Canada’s most senior public servant during a highly publicized parliamentary committee is analysed with a novel theoretical and empirical approach in three steps. First, the Clerk of the Privy Council (Clerk)’s committee testimony is analysed against analytical constructs of impartial and promiscuous partisan loyalty that focuses on the testimony’s direction and substance. Second, the objectivity and truthfulness of the testimony is analysed by comparing what was publicly claimed to have occurred against evidence submitted to the committee that provids an independent record of events. Third, the perception the Clerk’s testimony had on some committee members, political journalists and members of the public is analysed through print media and committee Hansard.

Findings

While the Clerk’s testimony displays an awareness of upholding impartiality, it also comprises promiscuous partisanship. Throughout his testimony, the Clerk redirects from the line of questioning to defend and promote the sitting government’s reputation. Moreover, to defend and promote the government’s reputation the Clerk’s testimony moved away from objectivity and engaged in truth-obfuscating tactics. Finally, the nature of the Clerk’s testimony was perceived by some committee members and the public—including former senior public servants—as having abandoned impartiality to have become a public “cheerleader” of the government.

Research limitations/implications

Employing an in-depth case study limits the extent to which the findings concerning the presence of promiscuously partisan loyalty can be generalized beyond the present case to the larger cadre of senior public servants.

Originality/value

Empirically, while most research has dismissed claims of promiscuous partisanship as empirically unfounded, this article provides what is possibly the strongest empirical case to date of a public incident of promiscuous partisanship at the apex of the bureaucracy. As such, scholars can no longer dismiss NPG as an interesting idea without much empirical leverage. Theoretically, this article adds further caution to Aucoin’s original narrative of NPG by suggesting that promiscuous partisanship might not only involve senior public servants defending and promoting the government, but that doing so may push them to engage in truth-obfuscating tactics, and therein, weaken the public’s confidence in political institutions. The novel theoretical and empirical approach to studying senior public servants’ parliamentary testimony can be used by scholars in other settings to expand the empirical study of bureaucratic loyalty.

Details

International Journal of Public Leadership, vol. 19 no. 2
Type: Research Article
ISSN: 2056-4929

Keywords

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