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The work efficiency and energy consumption of astronauts in the space station are the key issues in the operation of the space station, and how to evaluate the lean value of their activities is also complex and abstract. Combined with the idea of lean management, this paper aims to propose an space station dynamic value stream mapping system that can monitor and continuously improve the value flow and energy flow of astronauts in real time through lean methods.

Through systematic literature review, it is found that there is little research on the issue of lean management for astronauts. In manufacturing and services, value stream mapping is widely used for lean management. However, the static value stream map lacks the characteristics of real-time dynamics. This paper proposes to take the three modules of Muda detection, action recognition and energy monitoring as the basic content of the astronaut lean management framework to make the value stream and energy stream dynamic.

The theoretical framework of astronaut lean management is initially constructed, and the reasons for astronaut Muda and improvement ideas are also analyzed.

In fact, practitioners can use the proposed framework to identify the value of astronauts. Academically, these results collect research on dynamic value stream and lean management, providing a new way to identify value in aerospace using lean methods. Finally, the future research goals of astronaut lean management are put forward.

Contemporary focus on infections and deaths in the event of pandemics may distract health institutions and medical practitioners from the psychosocial consequences of the outbreak in individuals. In light of the devastation, persistency and scarcity of pandemics, it is imperative to delve into individuals' psychological state and self-preservation instincts when confronted with the environmental danger arising from pandemic conditions and the environmental restrictions being imposed.

Guided by the self-preservation theory, the authors advance a research model to elucidate the moderated mediation effect of secondary traumatic stress on an individual's reactions when faced with environmental danger and restriction. The authors also consider the moderating influence of environmental restriction and media use diversity. The authors subsequently validated the research model via a survey with 2,016 respondents in China. The authors employed PLS-SEM to analyze the data and assess the hypothesized paths.

Analytical results revealed that secondary traumatic stress fully mediated the impact of environmental danger on external reliance but suppresses the mediating effects on internal reliance. The authors further confirmed that environmental restriction moderated the relationship between environmental danger and reliance. Furthermore, the authors attest to the moderating influence of media use diversity on the relationship between secondary traumatic stress and external reliance.

This study not only extends the theoretical lens of self-preservation to public health emergencies but also yields practical guidelines for coping with pandemics. Insights from this study can be harnessed to aid populations worldwide in coping and recovering from pandemics.

The purpose of this study is to address the issue that the traditional V-shaped ball valve profile shape is limiting the flow control characteristics in a series structure and to optimize the design profile by proposing an open-hole profile.

This paper proposes a Gaussian process regression surrogate model based on the genetic algorithm optimization of swarm intelligence, combined with the Expected Improvement point addition criterion, to optimize and correct the design profile. The flow regulation performance of the optimized V-shaped regulating ball valve is verified through a combination of numerical simulation and experiment.

The results demonstrate that the optimized V-shaped regulating ball valve has higher flow regulation accuracy and a more stable flow regulation process. After optimization, the flow characteristic curve of the spool is closer to the ideal equal percentage characteristic. The simulation results of the flow field are consistent with the experimental results.

The proposed method significantly reduces the optimization time, has higher efficiency and solves the problem that traditional optimization methods struggle with, which is ensuring optimal flow regulation performance. Compared to the traditional trial-and-error optimization method, the proposed method is more effective. The feasibility of the method is supported by experimental results.

This study examines the effects of comparable companies, within the same industry, on cash-holding (CH) levels of a specific firm in the Stock Exchange of Thailand (SET). Peer effects are hypothesized to affect a firm's average CH levels.

The authors use data of listed firms in the Thai stock markets from 1995 to 2018. The sample consists of 5,277 firm-year observations. The authors perform robustness tests by incorporating gross domestic product, economy and competitiveness.

Peer firms' CH levels correspond positively to the specific firm's CH. This strengthens further for firms with high cash flow volatility during periods of high competition. Unfavorable economic periods also motivate the association between a firm's CH and peer firms' CH.

A policy on CH should account for cash held by peer firms. Firms can justify their CH policy as compatible with peers' cash flows, especially during periods of competitiveness and an unfavorable economy.

The authors provide novel evidence on how emerging markets' CH levels differ from those in developed markets and propose adjusted explanations for the rivalry- and information-based theories. The findings add substantial knowledge to corporate finance by arguing that CH policies are based on peer firms' strategic moves.