Yunhao Zhang, Chunlei Shao, Jing Kong, Junwei Zhou and Jianfeng Zhou
This paper aims to prevent gasket sealing failure in engineering, accurately predict gasket life, extend system life and improve sealing reliability. The accelerated life test…
Abstract
Purpose
This paper aims to prevent gasket sealing failure in engineering, accurately predict gasket life, extend system life and improve sealing reliability. The accelerated life test method of flexible graphite composite–reinforced gaskets is established, the life distribution law of flexible graphite composite–reinforced gaskets is revealed, and the life prediction method of flexible graphite composite–reinforced gaskets with different allowable leakage rates is proposed, which can provide a reference for the life prediction of other types of gaskets.
Design/methodology/approach
In this study, flexible graphite composite–reinforced gaskets were tested for long-term high-temperature sealing performance on a multi-sample gasket accelerated life test rig. The data were also analyzed using the least squares method and the K-S hypothesis calibration method. A gasket time-dependent leakage model and an accelerated life model were also developed. Constant stress-accelerated life tests were conducted on flexible graphite composite–reinforced gaskets. On this basis, a gasket life prediction method at different allowable leakage rates was proposed.
Findings
The life distribution law of flexible graphite composite–reinforced gaskets is revealed. The results show that the life of the gasket obeys the Weibull distribution. The time-correlated leakage model and accelerated life model of the gasket were established. And the accelerated life test method of the flexible graphite composite–reinforced gasket was established. The life distribution parameters, accelerated life model parameters and life estimates of gaskets were obtained through tests. On this basis, a gasket life prediction method under different leakage rates was proposed, which can be used as a reference for other types of gaskets.
Practical implications
The research in this paper can better provide guidance for the use and replacement of gaskets in the project, which is also very meaningful for predicting the leakage condition of gaskets in the bolted flange connection system and taking corresponding control measures to reduce energy waste and pollution and ensure the safe operation of industrial equipment.
Originality/value
A multi-specimen gasket-accelerated life test device has been developed, and the design parameters of the device have reached the international advanced level. The life distribution law of the flexible graphite composite–reinforced gasket was revealed. The accelerated life test method for the flexible graphite composite–reinforced gasket was established. The life prediction method of the flexible graphite composite–reinforced gasket under different allowable leakage rates was proposed.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-08-2023-0254/
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Haichen Zhou, Dejun Zheng, Yongming Li and Junwei Shen
To further provide some insight into mobile library (m-library) applications (apps) user needs and help libraries or app providers improve the service quality, the purpose of this…
Abstract
Purpose
To further provide some insight into mobile library (m-library) applications (apps) user needs and help libraries or app providers improve the service quality, the purpose of this paper is to explore all the types of user improvement needs and to discover which need is the most important based on user results.
Design/methodology/approach
Data were collected from more than 27,000 m-library app users from 16 provinces and autonomous regions in China. Text analysis using latent Dirichlet allocation and Word2Vec was carried out by text preprocessing. Furthermore, a visual presentation was conducted through pyLDAvis and word cloud. Finally, combined with expert opinions, the results were summarized to find the different types of needs.
Findings
There are three different types of needs for improvement: needs of function, needs of technology and needs of experience. These types can be further divided into six subtypes: richness of function, feasibility of function, easiness of technology, stableness of technology, optimization of experience and customization of experience. Besides the richness of function, the feasibility of function has received the most attention from users.
Originality/value
Most studies on m-library user needs have only focused on a method of quantitative research based on questionnaire surveys. This study, however, is the first to apply text mining methods for large-scale user opinion texts, which place more focus on user needs and inspire libraries and app providers to further improve their services.
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Junwei Wu, Xiao Wang, Luhai Zhou, Xicheng Wei and Wurong Wang
Serpentine is usually added into the lubricant oil to form a self-repairing protective layer on worn ferrous surface. But few works have paid close attention to the preparation of…
Abstract
Purpose
Serpentine is usually added into the lubricant oil to form a self-repairing protective layer on worn ferrous surface. But few works have paid close attention to the preparation of composites with the addition of serpentine. In this work, serpentine reinforced Al matrix composites were successfully prepared to be industrial lubrication components. And its fabricating parameters, compressive strength and tribological properties were analyzed.
Design/methodology/approach
An MM-W1 three-pin-on-disk apparatus was used to investigate the tribological properties. The worn surface, microstructure and cross-sectional morphologies were characterized by scanning electron microscopy equipped with energy dispersive spectroscopy. The compression test was carried out on a universal testing machine. An X-ray diffractometer was used to investigate the phase constitutions. The decomposition temperature of serpentine powders was investigated by a thermal analyzer, which allows simultaneous differential scanning calorimetry and thermogravimetry. With the help of finite element method model, a diagrammatic model of the self-repairing surface layer was developed to analyze the anti-friction mechanism.
Findings
Through evaluating density and Brinell hardness, sintering at 560°C for 3 h are the appropriate parameters for fabricating the composites. Compressive strength was increased by the addition of serpentine. A self-repairing surface layer was formed, reducing the friction coefficient. And a diagrammatic model of the self-repairing surface layer was developed to analyze the anti-friction mechanism.
Originality/value
Serpentine was added in fabricating the Al matrix composites for the first time. Sintering parameters were optimized to make better Al/Si/serpentine composites. Compressive strength was increased by the addition of serpentine. A self-repairing surface layer was formed, reducing the friction coefficient under the dry sliding condition. And a diagrammatic model of the self-repairing surface layer was developed to analyze the anti-friction mechanism. It is hoped to be helpful in further confirming the factors for the formation of the self-repairing surface layer, and in designing a new industrial anti-friction composite used for dry sliding conditions.
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Liu Junwei, Lu Shiqiang, Hou Jianbao, Ouyang Zipeng and Ren Mingliang
The effect of SBF artificial body fluid on microstructure and morphology characteristics of AZ91D alloy was investigated using OM, SEM and XRD. The effect of corrosion on…
Abstract
Purpose
The effect of SBF artificial body fluid on microstructure and morphology characteristics of AZ91D alloy was investigated using OM, SEM and XRD. The effect of corrosion on mechanical properties also was researched.
Design/methodology/approach
The results show that the corrosion weight loss rate initially increased, then clearly decreased, and finally remained steady. Pits began to appear when the sample was placed in a corrosive environment for five days and pitting gradually increased with longer exposure time.
Findings
The pits, which made the grain boundaries indistinct, first appeared near the grain boundary area and then gradually increased in area.
Originality/value
The main mode of corrosion is pitting and the primary corrosion product, MgOH2, could be observed after five days of corrosion.
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Kuang Junwei, Hangzhou Yang, Liu Junjiang and Yan Zhijun
Previous dynamic prediction models rarely handle multi-period data with different intervals, and the large-scale patient hospital records are not effectively used to improve the…
Abstract
Purpose
Previous dynamic prediction models rarely handle multi-period data with different intervals, and the large-scale patient hospital records are not effectively used to improve the prediction performance. This paper aims to focus on the prediction of cardiovascular disease using the improved long short-term memory (LSTM) model.
Design/methodology/approach
A new model based on the traditional LSTM was proposed to predict cardiovascular disease. The irregular time interval is smoothed to obtain the time parameter vector, and it is used as the input of the forgetting gate of LSTM to overcome the prediction obstacle caused by the irregular time interval.
Findings
The experimental results show that the dynamic prediction model proposed in this paper obtained a significant better classification performance compared with the traditional LSTM model.
Originality/value
In this paper, the authors improved the LSTM by smoothing the irregular time between different medical stages of the patient to obtain the temporal feature vector.
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Junwei Zheng, Xueqin Gou, Guangdong Wu, Xianbo Zhao, Hongyang Li and Bingsheng Liu
This study investigated the differential effects of empowering leadership and directive leadership in projects. Moreover, how the complex interplay between empowering and…
Abstract
Purpose
This study investigated the differential effects of empowering leadership and directive leadership in projects. Moreover, how the complex interplay between empowering and directive leadership styles influences both leader–member exchange and project performance was also explored.
Design/methodology/approach
Polynomial regression analysis and response surface modeling were applied to analyze 161 matched data collected from project members and managers worked in different projects located in China.
Findings
Four leadership styles were identified, i.e. ambidextrous, delegating, directive and laissez-faire styles. These may be combined with empowering and directive leadership. With regard to (in)congruence, leader–member exchange and project performance improved with ambidextrous style as a form of high–high congruence between empowering and directive leadership compared with laissez-faire style (i.e. low–low congruence). Results were better when a delegating style was combined with empowering leadership at a high level compared with the combination of directive style as directive leadership at a high level. Leader–member exchange was identified to exert a mediating role of the (in)congruence on project performance.
Originality/value
This study confirmed the contingent viewpoint of leadership by identifying distinct leadership styles applied in projects. Furthermore, the co-existence of empowering leadership and directive leadership was examined, and the underlying mechanism between the (in)congruence of empowering and directive leadership and project performance was identified.
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Jun Zhao, Hao Zhang, Junwei Liu, Yanfen Gong, Songqiang Wan, Long Liu, Jiacheng Li, Ziyi Song, Shiyao Zhang and Qingrui Li
Based on the weak seismic performance and low ductility of coupled shear walls, engineered cementitious composites (ECC) is utilized to strengthen it to solve the deformation…
Abstract
Purpose
Based on the weak seismic performance and low ductility of coupled shear walls, engineered cementitious composites (ECC) is utilized to strengthen it to solve the deformation problem in tall buildings more effectively and study its mechanical properties more deeply.
Design/methodology/approach
The properties of reinforced concrete coupled shear wall (RCCSW) and reinforced ECC coupled shear wall (RECSW) have been studied by numerical simulation, which is in good agreement with the experimental results. The reliability of the finite element model is verified. On this basis, a detailed parameter study is carried out, including the strength and reinforcement ratio of longitudinal rebar, the placement height of ECC in the wall limb and the position of ECC connecting beams. The study indexes include failure mode and the skeleton curve.
Findings
The results suggest that the bearing capacity of RECSW is significantly affected by the ratio of longitudinal rebar. When the ratio of longitudinal rebar increases from 0.47% to 3.35%, the bearing capacity of RECSW increases from 250 kN to 303 kN, an increase of 21%. The strength of longitudinal rebar has little influence on the bearing capacity of RECSW. When the strength of the longitudinal rebar increases, the bearing capacity of RECSW increases little. The failure mode of RECSW can be improved by lowering the casting height of the ECC beam in a certain range.
Originality/value
In this paper, ECC is used to strengthen the coupled shear wall, and the accuracy of the finite element model is verified from the failure mode and skeleton curve. On this basis, the casting height of the ECC casting wall limb, the strength and reinforcement ratio of longitudinal rebar and the position of the ECC beam are studied in detail.
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Hongyang Li, Anjie Xue, Junwei Zheng, Martin Skitmore and Matthew Moorhead
The current booming development of smart cities poses new requirements and challenges for their internal infrastructure development. This article aims to explore the questions…
Abstract
Purpose
The current booming development of smart cities poses new requirements and challenges for their internal infrastructure development. This article aims to explore the questions of: What is the level of social sustainability of smart city infrastructure today? and What are the core contents and paths to improve this level?
Design/methodology/approach
With the theme of public participation in the social sustainability evaluation of smart city infrastructure in the context of big data, this study mainly makes a systematic literature review of the Web of Science's Science Citation Index Expanded and Social Sciences Citation Index databases. After collection and screening, 199 documents were finally obtained.
Findings
It is found that the level of social sustainability of smart city infrastructure is still low, and public participation can provide solutions to the difficulties and challenges involved in its development, while big data technology can broaden the channels for public participation and promote the development of smart city-related components in the process, including smart city infrastructure.
Originality/value
This article summarizes the internal mechanisms of smart cities at the theoretical level and analyzes the social sustainable development of smart city infrastructure. In practice, the shortcomings in this field are identified and suggestions are provided on how to carry out digital public participation, which has practical reference value.
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Junwei Zheng, Yu Gu, Zhenduo Zhang, Hongtao Xie, Peikai Li and Hongyang Li
While existing literature emphasizes the importance of empowerment in construction projects, the working mechanisms of empowering leadership in the project context are unclear…
Abstract
Purpose
While existing literature emphasizes the importance of empowerment in construction projects, the working mechanisms of empowering leadership in the project context are unclear. Based on conservation of resources (COR) theory, this study aimed to examine the relationship between empowering leadership and project performance, highlighting the mediation roles of creative self-efficacy and leadermember exchange and the moderation role of perceived overqualification.
Design/methodology/approach
The authors collected data from 287 project members in different projects and tested the integrated conceptual model through moderated mediation analysis with bootstrapping strategy.
Findings
The results revealed that empowering leadership was positively related to project performance through creative self-efficacy and leader–member exchange. Perceived overqualification served as significant moderator.
Originality/value
The findings contribute to the understanding of empowering leadership in projects by verifying and extending the resource acquisition and investment process in the project context. The results of this study also demonstrated that creative belief and social exchange facilitate the effectiveness of project members' task efforts and outcomes and that perceived overqualification might not exert a detrimental effect on project performance.
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Yajun Zhang, Jingjing Wang, Junwei Zhang, Yongqi Wang and Muhammad Naseer Akhtar
While cyberloafing has emerged as a prevalent issue in numerous workplaces, research on its consequences is still underdeveloped, highlighting a need for further exploration and…
Abstract
Purpose
While cyberloafing has emerged as a prevalent issue in numerous workplaces, research on its consequences is still underdeveloped, highlighting a need for further exploration and analysis. Drawing upon the cognitive appraisal theory of emotion, this study investigates the influence of coworkers' cyberloafing on employees' workplace incivility, mediated by negative emotions and moderated by task interdependence.
Design/methodology/approach
In Study 1, the hypothesized research model was tested utilizing three-wave time-lagged survey data collected from 333 employees and their coworkers. In Study 2, an additional sample of 274 employees was surveyed. Data were analyzed using hierarchical regression analysis and the bootstrap method.
Findings
The results indicated that coworkers' cyberloafing positively influenced employees' workplace incivility, with this relationship mediated by negative emotions. Additionally, task interdependence was found to positively moderate both the direct relationship between coworkers' cyberloafing and negative emotions and the indirect path from coworkers' cyberloafing to employees' workplace incivility through negative emotions.
Practical implications
This study helps managers gain a deeper understanding of cyberloafing's effects, enabling them to manage and curb it more effectively.
Originality/value
Prior research has predominantly explored the effects of cyberloafing on its implementers. However, this study innovatively shifts focus to the observer perspective, empirically demonstrating whether and how coworkers' cyberloafing affects employees' workplace incivility, enriching and expanding the existing literature.