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Identifying the flow regime is a prerequisite for accurately modeling two-phase flow. This paper aims to introduce a comprehensive data-driven workflow for flow regime identification.

A numerical two-phase flow model was validated against experimental data and was used to generate dynamic pressure signals for three different flow regimes. First, four distinct methods were used for feature extraction: discrete wavelet transform (DWT), empirical mode decomposition, power spectral density and the time series analysis method. Kernel Fisher discriminant analysis (KFDA) was used to simultaneously perform dimensionality reduction and machine learning (ML) classification for each set of features. Finally, the Shapley additive explanations (SHAP) method was applied to make the workflow explainable.

The results highlighted that the DWT + KFDA method exhibited the highest testing and training accuracy at 95.2% and 88.8%, respectively. Results also include a virtual flow regime map to facilitate the visualization of features in two dimension. Finally, SHAP analysis showed that minimum and maximum values extracted at the fourth and second signal decomposition levels of DWT are the best flow-distinguishing features.

This workflow can be applied to opaque pipes fitted with pressure sensors to achieve flow assurance and automatic monitoring of two-phase flow occurring in many process industries.

This paper presents a novel flow regime identification method by fusing dynamic pressure measurements with ML techniques. The authors’ novel DWT + KFDA method demonstrates superior performance for flow regime identification with explainability.

The aerodynamic differences between the head car (HC) and tail car (TC) of a high-speed maglev train are significant, resulting in control difficulties and safety challenges in operation. The arch structure has a significant effect on the improvement of the aerodynamic lift of the HC and TC of the maglev train. Therefore, this study aims to investigate the effect of a streamlined arch structure on the aerodynamic performance of a 600 km/h maglev train.

Three typical streamlined arch structures for maglev trains are selected, i.e. single-arch, double-arch and triple-arch maglev trains. The vortex structure, pressure of train surface, boundary layer, slipstream and aerodynamic forces of the maglev trains with different arch structures are compared by adopting improved delayed detached eddy simulation numerical calculation method. The effects of the arch structures on the aerodynamic performance of the maglev train are analyzed.

The dynamic topological structure of the wake flow shows that a change in arch structure can reduce the vortex size in the wake region; the vortex size with double-arch and triple-arch maglev trains is reduced by 15.9% and 23%, respectively, compared with a single-arch maglev train. The peak slipstream decreases with an increase in arch structures; double-arch and triple-arch maglev trains reduce it by 8.89% and 16.67%, respectively, compared with a single-arch maglev train. The aerodynamic force indicates that arch structures improve the lift imbalance between the HC and TC of a maglev train; double-arch and triple-arch maglev trains improve it by 22.4% and 36.8%, respectively, compared to a single-arch maglev train.

This study compares the effects of a streamlined arch structure on a maglev train and its surrounding flow field. The results of the study provide data support for the design and safe operation of high-speed maglev trains.

This study aims to investigate the cause of high-order wheel polygonization in a plateau high-speed electric multiple unit (EMU) train.

A series of field tests were conducted to measure the vibration accelerations of the axle box and bogie when the wheels of the EMU train passed through tracks with normal rail roughness after re-profiling. Additionally, the dynamic characteristics of the track, wheelset and bogie were also measured. These measurements provided insights into the mechanisms that lead to wheel polygonization.

The results of the field tests indicate that wheel polygonal wear in the EMU train primarily exhibits 14–16 and 25–27 harmonic orders. The passing frequencies of wheel polygonization were approximately 283–323 Hz and 505–545 Hz, which closely match the dominated frequencies of axle box and bogie vibrations. These findings suggest that the fixed-frequency vibrations originate from the natural modes of the wheelset and bogie, which can be excited by wheel/rail irregularities.

The study provides novel insights into the mechanisms of high-order wheel polygonization in plateau high-speed EMU trains. Futher, the results indicate that operating the EMU train on mixed lines at variable speeds could potentially mitigate high-order polygonal wear, providing practical value for improving the safety, performance and maintenance efficiency of high-speed EMU trains.

This study delves into the less-explored domain of teachers’ readiness for leadership roles by investigating the direct and indirect relationships between positive school culture and teachers' readiness for leadership roles through affective-identity motivation to lead, and teacher optimism.

This study employed partial least squares structural equation modelling (WPLS-SEM) for data analysis. The data were gathered from 424 elementary school teachers who do not hold any leadership positions in Xi’an, China. A total of 391 samples were used after sampling weight adjustments.

There is a significant and positive direct relationship between positive school culture and teachers’ readiness for leadership roles. Affective-identity motivation to lead and teacher optimism emerged as significant mediators in this dynamic.

This study complements and expands on the study of the relationship between positive school culture, affective-identity motivation to lead, teacher optimism and teachers' readiness for leadership role. This research has established a theoretical framework for school stakeholders to cultivate future teacher leaders.

These findings provide valuable theoretical insights into educational leadership literature and contribute to a more comprehensive understanding of the factors influencing teachers in assuming leadership roles, particularly in the context of Asian societies.

Previous research has analyzed the consequence of network stability; however, little is known about how partner type diversity influence network stability in R&D network. Based on knowledge-based view and social network theory, the purpose of this paper is to unravel the internal mechanisms between partner type diversity and network stability through the mediating role of knowledge recombination in R&D network.

The authors collected an unbalanced panel patent data set from information communication technology industry for the period 1994–2016. Then, the authors tested the different dimensions of partner type variety and its relevance in the R&D network and the mediating role of knowledge recombination through adopting the multiple linear regression.

Results indicate an inverted U-shaped relationship between partner type diversity (variety and relevance) and network stability, whereas knowledge recombination partially mediate these relationships.

From the perspective of R&D networks, this paper explores that there are the under-researched phenomena the antecedent of network stability through nodal attributes (i.e. partner type variety and partner type relevance). Moreover, this paper empirically examined the mediating role of knowledge recombination in the partner type diversity–network stability relationships. The novel perspective allows focal firm to recognize importance of nodal attributes, which are critical to fully excavate the potential capabilities of cooperating partners in R&D network.

Many studies have investigated dynamic positions and their importance, but there is less attention paid to how to enter more central positions. Interorganizational relationships are an important factor in network structural change. In Chinese society, firms allocate significant human, financial and material resources towards cultivating guanxi. The purpose of this study is to explore whether and how the three aspects of guanxi, namely renqing, ganqing and xinyong, can make firms more central, and to examine the mediating role of interaction.

The study used a mixed method to collect data from 256 Chinese Cops (complex product systems) firms. And, hypotheses were tested using SPSS 25.0 and AMOS 26.0.

The results indicate that renqing, ganqing and xinyong have significant positive effects on the increase in centrality, but with varying magnitudes. Additionally, the interaction was found to mediate the relationship between the three aspects of guanxi (renqing, ganqing and xinyong) and the increase in centrality.

The study provides new insights to help firms become more central by combining guanxi (renqing, ganqing and xinyong) with change in centrality, enriching the literature on network dynamics and guanxi-related research. Moreover, the study provides managers with a clear understanding of how to use guanxi to make the firm more central in situations with limited resources.

This paper uses test panel data for the biggest companies listed on the boards of directors of the Palestine Stock Exchange from 2016 to 2022 and will focus on the relationship between the corporate governance index, accounting conservatism, and the comprehensive index of corporate governance.

The relationship between corporate governance and accounting conservatism is experimentally investigated for its impact on the likelihood of stock price breakdown and decline among companies listed on the Palestine Stock Exchange between 2016 and 2022, using a mixed utilities approach.

The findings demonstrated the adverse correlation between corporate governance, accounting conservatism, and stock prices. Higher levels of corporate governance can effectively reduce the likelihood of future stock price increases, while conservative accounting policies can effectively prevent stock price collapses in these listed companies. Higher levels of corporate governance can greatly lessen the detrimental effect of accounting conservatism on the likelihood of future stock price breakdowns and declines. Both accounting conservatism and corporate governance have substitution effects in decreasing the danger of stock price collapse.

The limitations of the current research are that higher levels of corporate governance can significantly reduce the harmful effect of accounting conservatism on the probability of stock price breakdown and decline in the future on the study sample used, and these results cannot be generalized to all company stocks that were excluded in this study. The last research limitation is that the sample size of this study is somewhat small, and therefore the effects of the results cannot be used on all unlisted companies, and they cannot be generalized to all of these companies except only to companies listed on the Palestine Stock Exchange.

Our findings have interesting managerial and policy implications. Listed firms should first strengthen external audit oversight, improve the method of disclosing accounting information, and improve the system architecture to raise the level of accounting conservatism. Moreover, it is imperative to enhance and improve the ownership structure of publicly traded firms, construct a robust mechanism for replacing shareholders, fortify the duties of the board of directors, proficiently fulfil the role of independent directors, and develop and refine the internal and external framework for corporate governance.

This study provides insights about reducing the probability of a stock market breakdown and collapse from two sides: enhancing corporate governance, improving accounting conservatism, enhancing the reliability and integrity of disclosure, and growing the number of sustainable disclosures. These suggestions can also be used as a template for Palestine's capital market's gradual and sustainable expansion.

The quality liability of prefabricated components (PCs) is a major issue among key stakeholders. The blockchain-based quality tracking systems are supposed to support a more transparent and trusting quality control process. However, many factors affect the stakeholders' willingness toward the adoption of such quality tracking systems. The purpose of this research is to investigate the key factors that influence the stakeholders' adoption decisions toward the application of the quality tracking system in PCs and develop coping strategies.

An evolutionary game model is established that includes the manufacturer, constructor and developer. Four scenarios of equilibriums and the game's evolutionary stable strategies are analyzed, and the corresponding stability conditions are then obtained. Based on the tripartite game model, two representative projects are used as case studies to simulate how different factors affect the stakeholders' decisions.

First, trade-offs between cost and benefits were the most prominent factor in the adoption decision-making. Second, the advancement of technologies would compensate for their immaturity. Third, subsidy and penalty provision of the developer and high-level trust both incentivize the stakeholders to adopt the quality tracking systems.

This research investigates the influence of technology, environment and participant related factors on the adoption decisions of the quality tracking system for PCs and discovered that technology maturity and advancement played an essential role. It is expected that the research findings would be of value to policy makers and project management personnel for better quality control of prefabricated construction.

The purpose of this study is to investigate the effectiveness of a composite lubrication system combining polytetrafluoroethylene (PTFE) film and oil lubrication in steel–steel friction pairs.

A PTFE layer was sintered on the surface of a steel disk, and a lubricant with additives was applied to the surface of the steel disk. A friction and wear tester was used to evaluate the tribological properties and insulation capacity. Fourier transform infrared spectrometer was used to analyze the changes in the composition of the lubricant, and X-ray photoelectron spectroscopy was used to analyze the chemical composition of the worn surface.

It was found that incorporating the PTFE film with PSAIL 2280 significantly enhanced both the friction reduction and insulation capabilities at the electrical contact interface during sliding. The system consistently achieved ultra-low friction coefficients (COF < 0.01) under loads of 2–4 N and elucidated the underlying lubrication mechanisms.

This work not only confirm the potential of PTFE films in insulating electrical contact lubrication but also offer a viable approach for maintaining efficient and stable low-friction wear conditions.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-06-2024-0222/

This study aims to evaluate the knowledge structure of knowledge management (KM) applications within small and medium enterprises (SMEs). In pursuit of excellence, SMEs must adopt KM like large corporations, even with limited resources.

Through a bibliometric approach, this study evaluates current themes based on bibliographic coupling analysis and predicts future trends based on coword analysis. A total of 726 documents and 2,658 keywords were derived from the Web of Science database.

Findings show four clusters in bibliographic coupling and three in coword analysis. A common theme discovered converged on digital technology to ensure SMEs follow current market trends.

Advanced application of Industry 4.0 requires digital transformation for SMEs’ pursuit of excellence. Implications include sustaining SMEs through a considerable KM system integrated with digital technology for sustainable business activities.

To the best of the authors’ knowledge, this study is among the first to provide a science mapping analysis on KM in SMEs by applying a bibliometric analysis.