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This paper aims to investigate the energy-saving effect and mechanism of serpentine as lubricant additive in the simulated condition.

An ABLT-1 bearing test machine was used for 1,350 hours and an MM-W1 three-pin-on-disk apparatus was used to investigate its anti-friction effect. The worn surface was characterized by scanning electron microscopy equipped with energy dispersive spectroscopy.

The results show that the energy-saving effect was improved after adding serpentine powder in oil and that both the friction coefficient and mass loss were dramatically decreased. The analysis on worn surface layer demonstrates that an auto-reconditioning surface layer was formed on the worn surface, which was responsible for the decrease in friction and wear.

The simulation test for the metal bearing was conducted over 1,350 hours using lubricant with and without serpentine powder. The addition of serpentine powder enhanced the energy-saving rate over time, stabilizing at about 13 per cent after 1,000 hours. An auto-reconditioning surface layer was formed on the surfaces of disassembled bearing lubricated with serpentine doped oil, resulting in dramatic decrease of both the friction coefficient and the mass loss. In addition to normal load and the accumulation of serpentine powder in the furrows and scratches of the deformed layer, the formation of the surface layer was possibly related to the substrate deformation induced by friction force.

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.

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.

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.

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.

This study aims to investigate how the strength of ties (i.e. strong ties and weak ties) in megaproject networks influences project performance in terms of types of conflicts.

A questionnaire survey was undertaken with professionals in Chinese megaprojects and 445 valid responses were received. A conflict-based theoretical model was developed and tested with structural equation modeling.

The results indicated that task conflict had a constructive effect on project performance, whereas relationship conflict and process conflict had destructive effects. Both strong and weak ties positively affected project performance, and that weak ties exerted greater effects on performance. The introduction of conflicts significantly weakened the effect of strong ties on project performance. Strong ties indirectly affected project performance via task conflict and relationship conflict, whereas weak ties affected performance only through task conflict. Task conflict had a constructive effect on project performance, whereas relationship conflict and process conflict had destructive impact.

This study identified the positive effect of strength of ties on project performance as well as the constructive and destructive roles of conflicts. Furthermore, the findings provided evidence that strength of ties and conflicts were critical factors for project performance. While, there are still limitations. There are other attributes of megaproject networks, such as network nodes’ characteristics and network structure, which may influence conflicts and project performance. Future research would be conducted to explore the role of these variables. Meanwhile, because different types of conflicts may mutually transform under certain conditions, future research would also address this issue in megaprojects.

As for the management strategies, project stakeholders should know the existence of project networks, exactly assess their resource endowment, especially their external and internal relationship network. In accordance with changes of the project network, stakeholders should share knowledge and learn techniques about how to respond to relationship disturbances, thus reducing relationship conflict and process conflict. Furthermore, stakeholders should place an emphasis on fostering and reinforcing communication and trust, thus effectively resolving task conflict, ambiguity and uncertainty engendered from network ties in a megaproject network.

The main contribution of this study is threefold. First, this study will enrich the literature on strength of ties by accentuating the roles of conflicts in megaproject context. Second, this study contributes to the theoretical development of a conceptual model for explaining the interrelationships among strength of ties, conflicts and project performance. Third, this study will respond to the call “which dimension, i.e. strong ties or weak ties, is more influential” by exploring the direct and indirect effects of strength of ties on project performance.

The purpose of this paper is to investigate the relationships between structure characteristics of project network, types of conflicts and project success.

Network density and centrality were used to reflect the structure characteristics of project network. This study collected 254 valid responses from construction professionals (including project managers, department managers and project engineers) via a questionnaire survey and analyzed the data using structural equation modeling and bootstrapping techniques.

The results showed that network centrality of project stakeholders negatively affected project success, whereas the effect of network density on project success was non-significant. The network density was positively related to task conflict, whereas negatively related to process and relationship conflict. Network centrality was positively related to relationship conflict and had negative effects on task and process conflict. Project conflicts served as the mediator, weakening the relationship between network structure characteristics and project success.

This study provides direction for project managers and other stakeholders (e.g. owners, contractors and subcontractors) to appropriately establish social ties and manage conflicts to achieve project success. However, the potential influence of conflict transformation on project success, the dynamic nature of project networks and the network diagram were not addressed in the context of diverse culture. The future research should cover different stakeholders in order to get an integrative understanding of project networks and collect data from different cultural and industrial characteristics, extending and verifying the results.

The outcomes of the study provide evidence in regard to social network ties governance, which is comprised by the important or representative stakeholders, being a part of the effective strategy in improving project success. This study also contributes to the knowledge of conflict management in the project context, revealing the positive and negative of project conflicts and enriching the current understandings of the underlying mechanism of the project network characteristics on project success.

The purpose of this paper is to examine the joint congruence effect of leadership styles and organizational culture on project members’ innovative behaviors in the construction projects setting.

The proposed hypotheses are tested using polynomial regression with a sample of 217 project managers and employees of different construction projects in China, and plotted through response surface analysis.

The results of polynomial regressions support the congruence effect hypothesis, indicating that more innovative behaviors of the project members could be elicited by a high level of congruence between transformational or transactional leadership styles and organizational culture. Furthermore, asymmetrical incongruence effects are found wherein project members with lower levels of innovative behaviors when project organizational culture is stronger as compared with when two leadership styles are at higher levels. Specifically, the condition is found under the innovation dimension of organization culture, but higher level of innovative behavior conversely displays when the harmony culture is weaker than two leadership styles.

The conceptual model and hypotheses are examined by analyzing cross-sectional and self-reported data collected in China. The findings could be further examined through multi-source or longitudinal, more systematic research.

The findings highlight the pivotal role played by the value congruence of leaders-organizations in motivating employees to be innovative in project organizations. This paper provides knowledge for project managers to help them understand whether and how project members’ innovative behaviors are better motivated by the fit or misfit between the styles of leadership and project organizational cultures. Besides, this study provides the approach or direction for the project leaders training.

This study is one of the first to examine the joint effects of leadership styles and organizational culture on innovative behavior based on the person-organization fit theory and from the perspective of value congruence.

This research aims to provide a theoretical method and data supports for a future study on interfacial reaction mechanism and spreading mechanism between molten solder and V-shaped substrate, which also gives guidance for those complicated welding operation objects in brazing technique.

Wetting experiments were performed to measure the contact angles at different temperatures of molten Sn-3.0Ag-0.5Cu wetting on the quartz substrate with an included angle of 90°. According to the experimental results, the theoretical spreading morphology of molten solder on V-shaped substrate at corresponding temperature was simulated by Surface Evolver.

The theoretical morphology profiles of the molten solder sitting on the V-shaped substrate are simulated using Surface Evolver when the molten solder reaches spreading equilibrium. The spreading mechanisms as well as the impact of surface tension and gravity on interfacial energy of the molten solder wetting on the V-shaped groove substrate are also discussed where theoretical results agree well with experiment results. The contact area between the gas and liquid phases shows a tendency of first increasing and later decreasing. Otherwise, the spreading distance and the height of the molten solder increases as the droplet volume increases as the included angle and the contact angle are given as constants, and both the interfacial energy and the gravitational energy increase as well. This research has a wide influence on predicting the outcomes in commercial impact and also gives guidance for those complicated welding operation objects in brazing technique.

It is of very important significance in both science and practice to investigate the differences between the flat surface and V-shaped surface. Some necessary parameters including intrinsic contact angle and surface tension need to be directly measured when the droplet spreads on the flat surface. The relevant simulation conclusions on the inherent characteristics can be given based on these intrinsic parameters. Compared with the flat surface, the V-shaped substrate is chosen for further discuss on the effects of gravity on the droplet spreading behavior and the changes of apparent contact angle which can only occurs as the substrate is inclined. Therefore, this research provides theoretical method and data supports for a future study on interfacial reaction mechanism and spreading mechanism between molten solder and substrate.

The research is developed for verifying the accuracy of the model built in Surface Evolver. Based on this verified model, other researches on the spreading distance along y-axis and the contact area that are especially difficult to be experimentally measured can be directly simulated by Surface Evolver, which can provides a convenient method to discuss the changes of horizontal spreading distance, droplet height and contact area with increasing the included angle of V-shaped substrate or with increasing the droplet volume. Actually, the modeling results are calculated for supplying the theoretical parameters and technical guidance in the welding process.

This research provides theoretical method and data supports for a future study on interfacial reaction mechanism and spreading mechanism between molten solder and substrate, which has a wide influence on prediction the outcomes in commercial impact and also gives guidance for those complicated welding operation objects in brazing technique.

Surface Evolver, can also be used to discuss the structure and spreading mechanism of droplets on V-shaped substrates, which have not been discussed before.

The development of project managers and leadership has been highlighted as crucial for improving project success and performance, resulting in a rise of interest in project leadership research over the last two decades. While several qualitative reviews have been conducted, there have been limited quantitative and systematic reviews on project leadership. This study fills this gap by portraying the knowledge landscape and tracking the evolution of project leadership research from 1998 to 2022 through bibliometric approaches.

Based on 816 records, including 793 articles extracted and selected from the Web of Science database and specific journals, and 23 articles selected from three non-SCI/SSCI indexed journals, the authors used CiteSpace and bibliometrix R-package to depict visualizations of the trajectory of co-cited references, the landscape of co-occurred keywords and emerging trends in project leadership via reference co-citation analysis, keyword co-occurrence analysis and thematic mapping.

The bibliometric analyses enabled the authors to understand the conceptual aspects of project leadership and its theoretical background. Three stages of the intellectual bases were identified and tracked: the infancy phase (1998–2007), the growth phase (2008–2014) and the new development phase (2015–2022). The results of keyword co-occurrence analysis indicated that the research focus evolved from investigating traits and competences to examining the effects of traditional leadership behaviors, and then considering context-specific leadership. The findings of thematic mapping and theoretical interpretation illustrate the potential directions of the competence comparison, new and appropriate leadership, and the interaction between leadership and context.

This study advanced the field by providing a systematic review of project leadership, developing potential future directions for project leadership research and providing practical implications for career development and training.

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.

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.

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.

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.

Following the conservation of resources theory and job demands–resources model, this study aims to explore the relationship between work interference with family (WIF) and emotional exhaustion and the boundary condition for construction professionals.

This study collected 319 valid samples from Chinese construction projects and examined the established integrative moderated mediation model using regression analysis and bootstrapping.

The results indicated that WIF was positively related to emotional exhaustion. The surface acting strategy mediated the relationship between WIF and emotional exhaustion. Emotional intelligence alleviated the indirect effect of WIF on emotional exhaustion via surface acting.

These findings unveil the resource depletion process of work–family conflict in the construction project context, enrich the emotional intelligence literature to demonstrate the buffer function on the negative impact of emotional resource depletion and address the implications for the construction labour workforce.

Drawing upon the conservation of resources (COR) theory, this study aims to examine whether ego depletion mediates the relationship between negative workplace gossip and employees’ service sabotage behavior and whether psychological resilience moderates the relationship between negative workplace gossip and service sabotage behavior through the mediator of ego depletion among hotel frontline employees and their colleagues.

A paired sample was collected at three-time points from employees and their colleagues working in hotels in Guizhou province, China. The PROCESS macro for SPSS was applied to examine the moderated mediation model.

The results showed that negative workplace gossip has a positive effect on employee service sabotage behavior, and that ego depletion mediates the relationship between negative workplace gossip and employee service sabotage behavior. Psychological resilience weakens the relationship between negative workplace gossip and ego depletion, as well as the indirect effect of negative workplace gossip on employee service sabotage behavior through ego depletion.

The present research provides a thorough understanding of when and how negative workplace gossip influences employee service sabotage behavior in the hospitality industry. The findings of this moderated mediation relationship expanded the boundary conditions of negative workplace gossip and employee service sabotage behavior.