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In today's digital and post-pandemic era, construction teams can span their boundary to obtain important resources and support in computer-mediated ways. However, the benefits of computer-mediated team boundary spanning (TBS) are mostly assumed. Empirical evidence for these benefits is in lack. Thus, this study attempts to investigate the influence of computer-mediated (instant messaging in this study) TBS on construction project performance and the underlying mechanism.

From the multiteam system (MTS) perspective, this study employs the input-process-outcome (IPO) framework and coordination theory to explore the influence of instant messaging-based team boundary spanning (IMTBS) on construction project coordination processes and project performance. A theoretical model is built and validated with a survey involving 206 construction projects.

Results show that IMTBS positively affects knowledge integration and project coordination, but negatively affects project commitment. The positive link between IMTBS and project performance is attributable to knowledge integration and project coordination. Further, project commitment is also found to negatively mediate the relationship between IMTBS and construction project performance.

To the best of the authors’ knowledge, this study is the first to empirically investigate the influence of TBS on construction project performance. As such, this study contributes to the literature on TBS in the construction field. In addition, the findings of this study unveil the double-edged characteristic of IMTBS, which should attract managers' attention. This also indicates that the form of TBS is a significant determinant of its effectiveness, which should attract scholars' attention in the future.

Timoshenko deformation calculation theory is suited to open section beam, which is not suited to closed section beam due to the difference stress distribution between the open and the closed section beam. This study aims to modify the deflection formula for prestressed concrete hollow slab (closed section beam) based on the Timoshenko theory.

(1) The deflection curves of the prestressed concrete hollow slab beam were obtained under a single point force; (2) linear phases of the deflection values, which were calculated by Timoshenko theory and ABAQUS, were compared with the measured values; (3) a modified coefficient related to the loading location was obtained to modify the Timoshenko theoretical formula in calculating the deflection of the prestressed concrete hollow slab.

(1) There is a large difference between the calculated values and the measured values at 4.3 < a/H < 7.7, and the differences are between 24 and 33 percent; (2) the Timoshenko deflection formula has been modified to fit for the calculation of the prestressed concrete hollow slab. The mean of f/ft is 1.01, and the variation coefficient is 0.09 after modification. Therefore, the modified formula can be better applied in the deflection calculation of the prestressed concrete hollow slab.

The Timoshenko theory is the most classical theory, which is often used to calculate the deformation of beams. The modified deflection formula for prestressed concrete hollow slab based on the Timoshenko theory is reliable and convenient, which can help engineers to calculate the deflection for closed section beam quickly.

Although previous research has recognized the pivotal role of mobile social media in knowledge sharing among project members, little is known about what factors affect knowledge sharing in mobile social media groups (MSMGs). Against this background, using normative social influence theory, this study attempts to explore factors influencing knowledge sharing in MSMGs.

Data from 205 Chinese construction project members are collected and used for analysis. Ordinary least squares regression by Stata 16 is used to test the proposed hypotheses.

Concerning role norms, gender difference in knowledge sharing behavior (KSB) is found, while it is not the case for knowledge quality (KQ). Work experience is found to positively affect KQ, but shows no influence on KSB. As for group norms, the inverted-U relationship between number of members and KSB is partially supported. In addition, organizational norms generally exhibit the greatest influence on both KSB and KQ among the three forms of norms.

This study deepens the understanding of knowledge sharing factors in mobile social media environments and affords practical implications for how to make full use of social media for knowledge management within construction project teams.

Despite the documented benefits of voice behavior for projects, little is known about antecedents of voice behavior in the project context, especially construction projects. Against this background, adopting a multi-team system perspective, this study attempts to investigate antecedents of team voice behavior from a contextual view.

This study identifies and examines six factors that influence team voice behavior. Specifically, project urgency, project temporality, and project complexity are identified from the project nature perspective. Satisfaction, trust, and commitment are generated from the relationship quality approach. Then, data from completed construction projects in China was collected to verify the effectiveness of these factors. Besides, the partial least squares structural equation modeling (PLS-SEM) technique was used in this study.

All six factors are found to be significant predictors of promotive team voice behavior. For prohibitive team voice behavior, only project complexity and project commitment make significant effects. Further, the differential effects of these factors on two types of voice behavior are revealed.

This study contributes to the literature on voice behavior in the project context, especially construction projects consisting of multiple teams. Also, this research enriches our knowledge on antecedents of team voice behavior in construction projects and thus affords practical implications to foster voice behavior.

A lack of reliable and effective communication tools poses major barriers impeding the performance of construction projects consisting of diverse participants. Although some construction project teams (CPTs) begin to apply social media (SM) as an available approach for project management the entire mechanism of SM adoption in this specific context remains understudied. Therefore, this study aims to adopt a CPT's lens to investigate the critical antecedents and associated effects underlying SM adoption in the construction industry.

Based on the technology–organization–environment (TOE) theory, a conceptual model was proposed and tested by empirical data collected from 159 CPTs in China. Structural equation modeling technique was employed for data analysis.

The results demonstrate that all the five extracted TOE-based antecedents including two technological factors (i.e. compatibility and expected cost), one organizational factor (i.e. top management support) and two environmental factors (i.e. project partner collaboration and project fit) are crucial to the adoption of SM in CPTs. Besides, SM acceptance is found to mediate the relationships between organizational and environmental factors and SM use. Moreover, SM use significantly predicts the communication effectiveness of CPTs.

A questionnaire study based on cross-sectional data from China may only unveil the logic of SM adoption in the context of Chinese construction industry within a shorter time interval. It is recommended that future research could develop longitudinal studies among various construction practitioners in different countries to further specify and generalize the current findings.

This paper provides a comprehensive understanding of SM adoption in the construction industry by exploring the preadoption antecedents and postadoption effects from the perspective of project teams. The empirical findings advance the current web-based project management literature and afford new insights for construction practitioners into better managing SM application to reap its full capabilities in projects.

This study aims to satisfy the thermal management of gallium nitride (GaN) high-electron mobility transistor (HEMT) devices, microchannel-cooling is designed and optimized in this work.

A numerical simulation is performed to analyze the thermal and flow characteristics of microchannels in combination with computational fluid dynamics (CFD) and multi-objective evolutionary algorithm (MOEA) is used to optimize the microchannels parameters. The design variables include width and number of microchannels, and the optimization objectives are to minimize total thermal resistance and pressure drop under constant volumetric flow rate.

In optimization process, a decrease in pressure drop contributes to increase of thermal resistance leading to high junction temperature and vice versa. And the Pareto-optimal front, which is a trade-off curve between optimization objectives, is obtained by MOEA method. Finally, K-means clustering algorithm is carried out on Pareto-optimal front, and three representative points are proposed to verify the accuracy of the model.

Each design variable on the effect of two objectives and distribution of temperature is researched. The relationship between minimum thermal resistance and pressure drop is provided which can give some fundamental direction for microchannels design in GaN HEMT devices cooling.

EU countries, including those in Central and Eastern Europe, seem to have increasingly similar economies, allowing for the study of real convergence as a process of equalising income levels (measured by GDP per capita). Studies of income convergence in the European Union also have a regional dimension and often focus on convergence at the NUTS2 or NUTS3 regional level. The level of development and income in Polish regions differ significantly. The regional policy implemented at the national and EU level focuses on reducing these differences.

The main aim of the chapter is to analyse the income convergence process among regions in Poland and verify the effectiveness of regional policy implemented at the national and EU level.

The study uses Barro type regression for panel data, log t convergence test, and club clustering algorithm introduced by Phillips and Sul to identify patterns of club convergence in Polish regions. The data used for the study is the Local Data Bank provided by Statistics Poland, which includes gross domestic product per capita at the NUTS-3 level for 73 Polish regions over the period of 2000–2020.

The results of the study indicate a very weak convergence process for all Polish NUTS-3 regions and suggest a club convergence. The club convergence is characterised by regions with similar income levels clustering together. The regional distribution of clubs is similar to the regional distribution of income. The study's findings provide important insights into the effectiveness of regional policy in Poland and suggest that policymakers need to focus on policies that promote catch-up growth in less developed regions. The study also highlights the importance of supporting the most developed regions in the country as they can play a crucial role in driving the country's economic growth and prosperity.

The purpose of this study is to explore the impact of asymmetric trust on construction project management performance in China's construction industry. Moreover, the authors explore the mediating role of two types of knowledge sharing (explicit knowledge sharing and tacit knowledge sharing) in explaining the association between asymmetric trust and project management performance.

A theoretical model based on the research hypotheses proposed in this study was developed and a questionnaire survey was conducted with 271 professionals. The data collected was analyzed by the structural equation modeling (SEM) technique.

The results of this study indicate that there is a significant and negative association between asymmetric trust and project management performance. Moreover, two types of knowledge sharing (explicit knowledge sharing and tacit knowledge sharing) have different degrees of impact on improving project management performance. In addition, tacit knowledge sharing is a mediator between asymmetric trust and project management performance.

The data used in this study is from Chinese scenarios, so the research conclusions and application effects based on this are bound to have certain regional limitations. Besides, there are many factors that affect project management performance improving, and the relationships among them are so complex. The theoretical model proposed in this study may not be fully considered. Therefore, follow-up researchers can consider bringing more suitable variables into their researches, so that the theoretical researches can be more in line with the actual project management practice, and the specific mechanism for improving project management performance can be explained more deeply.

This research's value is as follows: Firstly, this paper contributes to the trust and relational governance literature by expanding the research perspective of mutual trust to asymmetric trust. Specially, this research designs a measurement scale for asymmetric trust and then reveals the impact mechanism of it on project management performance, which will certainly promote research paradigm change of trust. Secondly, this research is beneficial to knowledge sharing literature in the construction management field by expanding the research scope of knowledge sharing from a cross-organizational perspective.

It is a crucial issue to eliminate cracks for selective laser melting (SLM) 7xxx series aluminum alloy. This paper aims to study the effect of silicon content on the cracking behavior and the mechanism of eliminating crack of SLMed Al7050 alloy.

Six different silicon contents were added to the Al7050 powder. The crack density and crack count measuring from optical micrographs were utilized to judge the cracking susceptibility. The low melting phases analyzing from Jmatpro and the microstructure observing by EPMA and SEM were used to discuss the mechanism of eliminating the crack.

The cracking susceptibility of SLMed Al7050 alloy decreases with the increase of adding silicon content. When adding silicon, two new low-melting phases appeared: Mg2Si and Al5Cu2Mg8Si6. These low-melting phases offer much liquid feeding along the grain boundary and decrease the cracking susceptibility. Moreover, the grains are obviously refined after adding silicon. The fine grain can increase the total surface area of the grain boundary, which can reinforce the matrix and decrease the cracking susceptibility. High silicon content results in more low-melting phases and fine grains, which decreases the cracking susceptibility.

The investigation results can help to obtain crack-free SLMed Al7050 parts and deep knowledge on eliminating cracking mechanism of high-strength aluminum alloy fabricated by SLM.

Fuel cells technologies are the most promising green energy technologies for diverse applications. One of the fastest growing areas is the portable electronic applications where the power range is the order of 1–100 W. For most of the portable electronic devices, rechargeable battery is the major energy source. Due to limitations like limited capacity, requirement of external power for recharge have led many researchers to look for alternative power sources to power portable electronic devices. The high energy density of fuel cells makes them very attractive alternative to batteries for portable power applications. There are a variety of fuel cell technologies being considered to replace batteries in portable electronic equipment. Direct Liquid Fuel Cells (DLFCs) have attracted much attention due to their potential applications as a power source for portable electronic devices. The advantages of DLFCs over hydrogen fed PEM fuel cells include a higher theoretical energy density and efficiency, a more convenient handling of the streams, and enhanced safety. Unlike batteries, fuel cells need not be recharged, merely refueled. This paper provides an overview on challenges of DLFCs (Direct Liquid Fuel Cells), like fuel crossover, cost, durability, water management, weight and size along with approaches being investigated to solve these challenges. Portable Fuel Cell Commercialization Targets for future and producers of portable fuel cells across the globe are also discussed in this paper.