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The purpose of this paper, computational fluid dynamics (CFD) work, is to promote turbulent thermal convection in a heated circular tube using a passive scheme of a slotted twisted sheet.

The inventive design uses square-cut and conjugate triangular perforations to diversify the twisted tape for better thermal convection. The current novel passive scheme methodology is accomplished by carving the same square cuts and slitting various sizes of equilateral triangle perforations (side length varies between 8 and 16 mm). The re-normalisation group turbulence model and the semi-implicit method for pressure-linked equation method examine the turbulent thermal convection aspects of all simulations at different Reynolds numbers (6,000, 10,000 and 14,000).

The analyses of simulations exhibit that the placement of a twisted tape with triangle perforations and equidistant square cuts can effectually promote thermal convection in a circular tube. A larger-sized triangle perforation can increase the thermal convection enhancement and thermal performance factor, but an enlarged perforation may decrease the thermal convection enhancement and thermal performance factor. As a result, compared with the smooth circular tube, the circular tube with the slotted twisted sheet slit by a 10 mm equilateral triangle brings about the maximum improvement ratio of the mean Nusselt number of about 2.8 at Re = 6,000. Under weighing the friction through the circular tube, the tube with the slotted twisted sheet slit by a 10 mm equilateral triangle gains the best thermal performance factor of about 1.36 at Re = 6,000.

The working fluid is water and its physical features are assumed to be constant. In addition, the fluid is considered a steady flow in this CFD work.

These CFD predictions will benefit the development of heat exchanger tubes equipped with a slotted twisted sheet to acquire preferable thermal convection enhancement.

Higher thermal performance achieved by placing a slotted twisted tape in a heated tube will benefit society in lower energy consumption, machinery maintenance costs and impact on the environment.

This study combined triangle perforations and square cuts on the twisted sheet. This combination can induce the fluid flow across the sheet to disturb the swirling flow and then promote the fluid mixing to increase thermal convection. Therefore, this modified tape can be a profitable passive device for designing a heat exchanger.

This research explores the complex interplay of multiple social factors with regard to what might encourage or inhibit users to interact with social commerce (SC).

To investigate the phenomenon, we developed a model based on goal-directed behaviour and pluralistic ignorance theory (typically generated by universal behavioural adherence to social norms). Based on the 394 valid responses collected from a survey, partial least squares structural equation modelling (PLS-SEM), PROCESS and ANOVA were employed to examine the research hypotheses.

The results show that pluralistic ignorance and commercial desire positively influence SC intention. More importantly, our results show that the moderating effect of pluralistic ignorance dampens the positive relationship between social subjective norms and commercial desire. The findings also suggest that pluralistic ignorance mediates the relationships between: (1) social identity and SC intentions and (2) fear of isolation and SC intentions.

Consequently, this study reveals that SC intentions result from complex interactions between an individual’s psychology and social phenomena. Theoretical and managerial implications are also discussed to provide for the successful development of strategies regarding SC for researchers and SNSs operators.

Drawing upon social-exchange, social-cognitive and leadership theory, this study explores whether and how a cross-level mechanism connects team-level traditional Chinese leadership (i.e. paternalistic leadership) to individual-level voice behavior.

Survey data were collected from 421 employees of 108 branches of four service-industry chains in Taiwan. Multilevel path models and hypotheses were tested using Mplus structural equation modeling software.

One subtype of team-level paternalistic leadership, benevolent leadership, was positively related to voice behavior, whereas another – authoritative leadership – had a negative relationship to it. Additionally, employees' voice self-efficacy and felt accountability each played a cross-level mediating role between team-level paternalistic leadership and voice behavior.

It is recommended that team leaders behave benevolently, and avoid excessive authoritativeness at work, as this will tend to encourage their employees to voice opinions. Organizations, meanwhile, are advised to introduce training and development sessions aimed at improving both felt accountability and voice self-efficacy among their employees, so that such voice behavior can be stimulated and strengthened.

This study provides a useful social-cognitive analysis of the mechanism underlying paternalistic leadership and employee voice behavior, and specifically, reveals that employees' felt accountability and voice self-efficacy play a mediating role in that relationship. This extends understanding of the leadership–voice relationship and adds value to traditional Chinese leadership literature.

The purpose of this paper is to develop a research model that explains team performance based on social cognitive theory and social exchange theory. In the model, team performance indirectly relates to three kinds of leadership (i.e., charismatic, autocratic and considerate) via the full mediation of collective efficacy. At the same time, team justice as a focus in this study is examined as a moderator in the model.

The research hypotheses of this study were empirically tested using two-wave data collection across insurance sales teams from a leading bank holding company which is the largest bank holding company in Taiwan. In the first-wave data collection, researchers of this study surveyed six people anonymously from each sales team, including a team leader and five team members. Three months later, the researchers conducted the second-wave data collection by obtaining team performance data from the department of human resource management, which was an independent rater for each team’s performance. Two-wave data collection from 59 teams was achieved for verifying the hypothesized effects.

The team-level test results show that collective efficacy fully mediates the relationship between charismatic leadership and team performance and between considerate leadership and team performance. Justice moderates the relationship between collective efficacy and team performance and between charismatic leadership and collective efficacy.

This study has two major theoretical implications. First, this study conceptualized three distinct kinds of leadership as major determinants of team performance from a social exchange perspective. Such a theoretical conceptualization of leadership not only broadens the boundary of leadership beyond traditional one such as transactional leadership based on the theory of contingent reward but also closely reflects the practical status quo of leadership of teams. Second, this research incorporated social exchange theory into the framework of team performance in social cognitive theory. Specifically, this study theorized and validated justice as a moderator in the development of team performance.