Yanqiu Chen, Xiaodong Zhou, Taolin Zhang, Yuqi Hu and Lizhong Yang
– The purpose of this paper is to study the behavior of smoke flow in a typical high-rise residential building fire in six common smoke control systems.
Abstract
Purpose
The purpose of this paper is to study the behavior of smoke flow in a typical high-rise residential building fire in six common smoke control systems.
Design/methodology/approach
The pressure, temperature and CO2 concentration were used to trace the motion of turbulent smoke flow through CFD.
Findings
It is found that the hot smoke could rise up and spread into the indoor space on the upper floors through the staircase. When the pressure in the evacuation staircase is higher, it would be more difficult for the smoke to enter the staircase and transport vertically. On the other hand, the smoke would soon transport to the indoor space on the upper floors horizontally. During this process, the smoke shows a more disorder horizontal transport under the sole effect of thermal buoyancy than the co-existence of thermal buoyancy and the air inlet.
Research limitations/implications
Because of the chosen research approach, the research results may need to be tested by further experiments.
Practical implications
The paper includes implications for the design of smoke control systems and evacuation in a building fire.
Originality/value
This paper fulfils an identified need to study the behavior of smoke in a fire and optimize the design of smoke control systems.
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Yanqiu Chen, Xiaodong Zhou, Taolin Zhang, Zhijian Fu, Yuqi Hu and Lizhong Yang
– The purpose of this paper is to study the behavior of smoke flow in building fires and optimize the design of smoke control systems.
Abstract
Purpose
The purpose of this paper is to study the behavior of smoke flow in building fires and optimize the design of smoke control systems.
Design/methodology/approach
A total of 435 3-D fire simulations were conducted through NIST fire dynamics simulator to analyze thermal behavior of combined buoyancy-induced and pressure-driven smoke flow in complex vertical shafts, under consideration of influence of heat release rate (HRR) and locations of heat sources. This influence was evaluated through neutral pressure plane (NPP), which is a critical plane depicting the flow velocity distributions. Hot smoke flows out of shafts beyond the NPP and cold air flows into shafts below the NPP.
Findings
Numerical simulation results show that HRR of heat source has little influence on NPP, while location of heat source can make a significant difference to NPP, particularly in cases of multi-heat source. Identifying the location of NPP helps to develop a more effective way to control the smoke with less energy consumption. Through putting an emphasis on smoke exhausting beyond the NPP and air supplying below the NPP, the smoke control systems can make the best use of energy.
Research limitations/implications
Because of the chosen research approach, the research results may need to be tested by further experiments.
Practical implications
The paper includes implications for the optimization of smoke control systems design in buildings.
Originality/value
This paper fulfills an identified need to research the behavior of hot smoke in building fires and optimize the design of smoke control systems.
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Chuansheng Wang, Ning Cai, Dewei Zhang, Jinxiu Zhang, Tianhao Chang, Shaoming Li, Yuqi Chao and Jiquan Hu
This purpose of this study was to develop a 3D printer based on powder particle. The best degreasing and sintering process of a blank body was investigated to obtain a metal…
Abstract
Purpose
This purpose of this study was to develop a 3D printer based on powder particle. The best degreasing and sintering process of a blank body was investigated to obtain a metal product with high precision and high surface finish. This process will greatly reduce the difficulty and cost of forming a complex metal product with high application value.
Design/methodology/approach
Stainless steel powder and polymer materials were mixed using a rubber mixing machine. The powders were granulated to prepare a mixed material. A powder feed 3D printer was used at low temperature (about 200°C) to print and degrease the body. A series of sintering experiments were performed to study the different sintering temperatures, and the physical and mechanical properties of the sample sintered under various conditions were compared to determine the best degreasing and sintering process.
Findings
The reaction at 1,370°C was the optimal route for the metal billet degreasing. The resulting metal products had fine structure and stable performance compared with the products with traditional powder metallurgy composition.
Originality/value
Most 3D printed metal powder materials rely on imports, which are expensive and increase the manufacturing cost. These drawbacks limit the application and development of metal 3D printing technology to a certain extent. The successful study of this molding method greatly reduces the difficulty and cost of forming complex metal products with high application value. This report will provide valuable guidance for sintering process and forming methods.
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Yuqi Wu, Huiwen Zhan, Lianying Hong and Weijie Hu
From the perspective of intangible knowledge resources, this paper clarifies the impact of managerial ability on the performance of overseas investment subsidiaries. It explains…
Abstract
Purpose
From the perspective of intangible knowledge resources, this paper clarifies the impact of managerial ability on the performance of overseas investment subsidiaries. It explains the dilemma that the rapid growth of overseas investment by enterprises in emerging markets has not brought about the corresponding expected performance.
Design/methodology/approach
This paper uses matching data between the parent companies and overseas subsidiaries of Chinese A-share listed companies from 2007 to 2022 to study the impact of managerial ability on the performance of overseas investment subsidiaries and its mechanism.
Findings
The results show that there is a significant positive correlation between managerial ability and the performance of overseas subsidiaries. However, the impact of managerial ability exhibits heterogeneous, which is more significant in non-state-owned enterprises, investments in high-income economies and M&A investment. Managerial ability promotes mainly the performance of overseas subsidiaries through R&D knowledge resources, marketing knowledge resources and internationalization experience; managerial ability significantly impacts the performance of overseas subsidiaries in the case of CEO two-job separation, low CEO shareholding level, the executive team with overseas background and female.
Originality/value
This paper introduces managerial ability as a critical intangible knowledge resource in the study of overseas investment performance, enriching and expanding the connotation and theoretical foundation of managerial ability. It clarifies the impact mechanism of managerial ability on overseas investment performance from three dimensions: R&D knowledge resources, marketing knowledge resources and internationalization experience. It provides new empirical evidence and management enlightenment for promoting overseas investment performance and high-quality development in emerging market countries.
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Yuqi Yang, Bing Wu, Guanwen Xiao and Quan Shen
The purpose of this study is to develop a 3D wheel-rail adhesion model under wet condition, which considers the generated surface roughness topography and the traditional braking…
Abstract
Purpose
The purpose of this study is to develop a 3D wheel-rail adhesion model under wet condition, which considers the generated surface roughness topography and the traditional braking procedure for high-speed trains.
Design/methodology/approach
Wheel-rail adhesion has an important effect on the braking ability of railway vehicle. Based on the deterministic mixed lubrication approach, the model was solved to get the adhesion characteristics of the train during braking. The elastic deformation was calculated with the discrete convolution and fast Fourier transform method. The simulation results of adhesion coefficient were compared with the experimental values. The wheel-rail adhesion characteristics of train braking at several different initial speeds were investigated. The effects of the time-step length and roughness orientation on the contact load ratio were also discussed.
Findings
The results show that the adhesion coefficient of the numerical model is in good agreement with the experimental results. At the instant of braking, the adhesion coefficient drops to a lower adhesion level, the value of adhesion coefficient is lower than 0.06, especially at a higher speed (200, 300 and 400 km/h).
Originality/value
It can provide a better understanding of the low adhesion phenomenon of train braking under wet condition.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-02-2023-0040/
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Abstract
Purpose
Based on social cognitive theory, this study aims to investigate the influence of perceived overqualification (POQ) on employees’ cyberloafing behavior. The mediating role of moral disengagement and the moderating roles of organizational identification (OID) and organizational decline are further examined.
Design/methodology/approach
The authors collected 740 valid questionnaires from participants across multiple organizations. To minimize common method bias (CMB) and enhance the reliability of the findings, data were gathered at two different time points, with a 30-day interval.
Findings
POQ positively impacts cyberloafing through the mechanism of moral disengagement. Additionally, the indirect relationship between POQ and cyberloafing via moral disengagement is moderated by OID and organizational decline. Specifically, a higher degree of OID weakens the indirect effect of POQ on cyberloafing, while a higher level of perceived organizational decline strengthens this effect.
Originality/value
While most existing studies on cyberloafing focus on insufficient resources, such as role conflict and workload, the authors propose that surplus personal resources, exemplified by POQ, can also lead to cyberloafing. This research contributes to a broader understanding of antecedents of cyberloafing, highlighting the mechanism of ethical considerations and the interplay between personal qualifications, organizational identification and organizational decline.
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Yue Zhang, Changjiang Zhang, Sihan Zhang, Yuqi Yang and Kai Lan
This study aims to examine the risk-resistant role of environmental, social and governance (ESG) performance in the capital market, focusing on an organizational standpoint…
Abstract
Purpose
This study aims to examine the risk-resistant role of environmental, social and governance (ESG) performance in the capital market, focusing on an organizational standpoint. Furthermore, it aims to offer management decision advice to companies seeking protection against stock market risks. Conclusions obtained through this research have the potential to enrich the economic consequences of ESG performance, provide practical implications for enhancing corporate ESG performance, improving corporate information quality and stabilizing capital market development.
Design/methodology/approach
Based on the data of Chinese A-share listed companies from 2009 to 2020, this study examines the risk-resistant function of ESG performance in the capital market. The impact of ESG performance on management behavior is analyzed from the perspective of organizational management and the three mechanisms of pre-event, during the event and post-event.
Findings
This paper demonstrates that companies that effectively implement ESG practices are capable of effectively mitigating risks associated with stock price crashes. Heterogeneity analysis reveals that the inhibitory effect of ESG performance on stock price crash risk is more pronounced in nonstate-owned enterprises and enterprises with higher levels of marketization. After controlling for issues such as endogeneity, the conclusions of this paper are still valid. The mechanism analysis indicates that ESG performance reduces the risk of stock price crash through three paths of organizational management: pre-event, during the event and post-event. That is, ESG performance plays the role of restraining managers’ opportunistic behavior, reducing information asymmetry and boosting investor sentiment.
Originality/value
This paper provides new insights into the relationship between ESG performance and stock price crash risk from an organizational management perspective. This study establishes three impact mechanisms (governance effect, information effect and insurance effect), offering a theoretical basis for strategic corporate decisions of risk management. Additionally, it comprehensively examines the contextual differences in the role of ESG performance, shedding light on the specific domains where ESG practices are influential. These findings offer valuable insights for promoting stable development in the capital market and fostering the healthy growth of the real economy.
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Zhiwei Yang, Qingshan Zhou, Dickson K.W. Chiu and Yuqi Wang
Academic social network site (ASNS) is a new form of academic service in the social media age, and the study of ASNS user behavior is of great significance to academic librarians…
Abstract
Purpose
Academic social network site (ASNS) is a new form of academic service in the social media age, and the study of ASNS user behavior is of great significance to academic librarians due to its recent popularity. This research explores the influencing factors of the continuous usage intention of ASNSs.
Design/methodology/approach
A survey of academics in China was conducted, and 361 responses were collected and analyzed with a structural equation model, which involves satisfaction, continuous usage intention, expectation confirmation, perceived usefulness (PU), social identity, referent network size and perceived interactivity (PI).
Findings
Satisfaction, expectation confirmation, PU, referent network size, social identity and PI significantly impact continuous usage intention. Satisfaction is a mediating variable by which expectation confirmation, PU, referent network size, social identity and other influencing factors affect continuous usage intention. Expectation confirmation and referent network size are two endogenous variables that can explain and predict the continuous usage intention of ASNSs.
Originality/value
Existing research does not consciously distinguish between adoption, use and continuous use, and only scant studies have conducted empirical research. Further, despite the widespread ASNS usage in China, Chinese scholars' studies are few, as existing studies have mainly focused on users of the UK, the US and India.
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Propose a more comprehensive explanation on the determinants and fluctuations of China’s exchange rate policy in the past decade (2005–2015).
Abstract
Purpose
Propose a more comprehensive explanation on the determinants and fluctuations of China’s exchange rate policy in the past decade (2005–2015).
Approach
Case study on China’s exchange rate policies in three respective stages since 2005 and then a comparative study on these three stages.
Findings
Put forward a two-pronged explanation on the determinants and fluctuations of China’s exchange rate policy in the past decade and arrive at three specific conclusions. First, external pressure is only one factor among many influencing the formation of China’s national interests (Guojia Liyi in Chinese) and the decision-making process on exchange rate policy. Second, national interest is the fundamental driving force and substratum for making China’s exchange rate policy. Third, in the short term, the specific exchange rate policies in different periods were not always in accordance to the national interests (or Guojia Liyi), due to the influences of some factors on the decision-making environment.
Value
The comprehensive view is conducive to better explaining the formation and fluctuations of China’s exchange rate policy and consequently contributes to understanding and even predicting future policies.
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Xiaoping Zhang, Yanhui Li, Meixiu Li, Qiuju Du, Hong Li, Yuqi Wang, Dechang Wang, Cuiping Wang, Kunyan Sui, Hongliang Li, Yanzhi Xia and Yuanhai Yu
In order to discover a new adsorbent that can be used to purify dye wastewater in the textile and apparel industry, a novel type of graphene oxide/gluten composite material using…
Abstract
Purpose
In order to discover a new adsorbent that can be used to purify dye wastewater in the textile and apparel industry, a novel type of graphene oxide/gluten composite material using an improved acid bath coagulation method was synthesized, which can remove methylene blue in an aqueous environment.
Design/methodology/approach
After experimentally compounding different ratios of graphene oxide and gluten, the graphene oxide/gluten composite material with 20% graphene oxide content and superlative adsorption effect was chosen. The synthesized material was characterized by different techniques such as FT-IR and SEM, indicating the microstructure of the material and the success of the composite. Various factors were considered, namely, the influence of temperature, dosage, pH and contact time. The isotherms, kinetics and thermodynamic parameters were successively discussed.
Findings
The qmax value of 214.29 mg/g of the material was higher compared to the general sorbent, thus, the graphene oxide/gluten composite material was a suitable sorbent for methylene blue removal. Overall, the graphene oxide/gluten composite material can be considered as an effectual and prospective adsorbent to remove methylene blue in the textile and apparel industrial effluent.
Originality/value
Graphene oxide is a potentially excellent sorbent. However, the high dispersibility of GO is detrimental to adsorption, it disperses rapidly in an aqueous solution making separation and recovery difficult. The high load capacity and recyclability of gluten as a colloid make it a suitable carrier for fixing GO. Studies on the combination of GO and GT into composite adsorption material and for the removal of dyes from dyeing wastewater have not been reported. The composite material research on GO and GT can provide new ideas for the research of these kinds of materials and contribute to its wider and convenient application in wastewater treatment.