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Article
Publication date: 13 June 2022

Bao Li, Wanming Chen, Changqing He and Yuwen Zhang

Team autonomy is thought to be important for team innovation performance. However, the theoretical basis of the relationship between team autonomy and team innovation performance…

Abstract

Purpose

Team autonomy is thought to be important for team innovation performance. However, the theoretical basis of the relationship between team autonomy and team innovation performance is not well understood, and previous studies have found inconsistent relations between them. Based on motivated information processing in groups (MIP-G) theory, this paper aims to explain how and when team autonomy could influence team innovation performance from a new team-level perspective.

Design/methodology/approach

Using a two-wave, time-lagged survey design, the authors collected data from 340 members of 86 teams in China. PROCESS 3.0 for SPSS was used to test hypothesized relationships.

Findings

The results show that team autonomy is positively related to team information exchange. Team information exchange mediates the positive relationship between team autonomy and team innovation performance. Furthermore, the positive relationship between team autonomy and team information exchange is stronger with less task conflict, which runs contrary to the hypothesis. Additionally, relationship conflict does not adjust the impact of team autonomy on team information exchange.

Originality/value

This study provides a new perspective to explain the mechanism between team autonomy and team innovation performance at team level from the information processing approach, specifically, MIP-G theory. It also incorporates team conflicts as important contextual factors to answer the call for a wider study of boundary conditions in the team autonomy research.

Details

International Journal of Conflict Management, vol. 33 no. 5
Type: Research Article
ISSN: 1044-4068

Keywords

Article
Publication date: 6 January 2012

Piyasak Damronglerd, Yuwen Zhang and Mo Yang

The purpose of this paper is to solve solidification of liquid copper saturated in porous structure fabricated by sintered steel particles using a temperature‐transforming model…

Abstract

Purpose

The purpose of this paper is to solve solidification of liquid copper saturated in porous structure fabricated by sintered steel particles using a temperature‐transforming model (TTM).

Design/methodology/approach

The convection in the liquid region is modeled using Navier‐Stokes equation with Darcy's term and Forchheimer's extension. The effect of natural convection is considered using the Boussinesq approximation. For the solid region, the velocity is set to zero by the Ramped Switch‐Off Method (RSOM). The model was validated by comparing the results with existing experimental and numerical results with gallium as phase change material and packed glass beads as porous structure. Solidification of liquid copper saturated in sintered copper particles is then simulated and the effects of various parameters on solidification process were studied.

Findings

The results indicate that the stronger convection effects are shown for the cases with high Raleigh number or high Darcy's number. However, when either Raleigh number or Darcy's number is reduced to below a certain order of magnitude, the solidification becomes conduction‐controlled.

Originality/value

This work is the first application of the TTM to solve solidification in porous media, which can find its application in post‐processing of laser sintered parts.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 22 no. 1
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 1 February 2006

Zhanhua Ma and Yuwen Zhang

To study the effects of velocity correction schemes for a temperature transforming model (TTM) for convection controlled solid‐liquid phase‐change problem.

Abstract

Purpose

To study the effects of velocity correction schemes for a temperature transforming model (TTM) for convection controlled solid‐liquid phase‐change problem.

Design/methodology/approach

The effects of three different solid velocity correction schemes, the ramped switch‐off method (RSOM), the ramped source term method (RSTM) and the variable viscosity method (VVM), on a TTM for numerical simulation of convection controlled solid‐liquid phase‐change problems are investigated in this paper. The comparison is accomplished by analyzing numerical simulation and experimental results of a convection/diffusion phase‐change problem in a rectangular cavity. Model consistency of the discretized TTM is also examined in this paper. The simulation results using RSOM, RSTM and VVM in TTM are compared with experimental results.

Findings

In order to efficiently use the discretized TTM model and obtain convergent and reasonable results, a grid size must be chosen with a suitable time step (which should not be too small). Applications of RSOM and RSTM‐TTM yield identical results which are more accurate than VVM.

Originality/value

This paper provides generalized guidelines about the solid velocity correction scheme and criteria for selection of time step/grid size for the convection controlled phase change problem.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 16 no. 2
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 1 August 2002

M.B. Shafii, A. Faghri and Yuwen Zhang

An advanced heat transfer model for both unlooped and looped Pulsating Heat Pipes (PHPs) with multiple liquid slugs and vapor plugs has been developed. The thin film evaporation…

1600

Abstract

An advanced heat transfer model for both unlooped and looped Pulsating Heat Pipes (PHPs) with multiple liquid slugs and vapor plugs has been developed. The thin film evaporation and condensation models have been incorporated with the model to predict the behavior of vapor plugs and liquid slugs in the PHP. The results show that heat transfer in both looped and unlooped PHPs is due mainly to the exchange of sensible heat. Higher surface tension results in a slight increase in the total heat transfer. The diameter, heating wall temperature, and charging ratio have significant effects on the performance of the PHP. Total heat transfer significantly decreased with a decrease in the heating wall temperature. Increasing the diameter of the tube resulted in higher total heat transfer. The results also showed that the PHP could not operate for higher charge ratios.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 12 no. 5
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 4 January 2016

Fariborz Karimi Talkhoncheh, Hongtao Xu, Zhiyun Wang, Mo Yang and Yuwen Zhang

– Unsteady simulation of forced convection of two heated horizontal cylinders confined in a 2D squared enclosure. The paper aims to discuss this issue.

Abstract

Purpose

Unsteady simulation of forced convection of two heated horizontal cylinders confined in a 2D squared enclosure. The paper aims to discuss this issue.

Design/methodology/approach

The finite-volume method is used to solve the transient heat transfer problem by employing quadrilateral mesh type. To solve the governing equations (conservations of mass, momentum and energy) on unstructured control volumes, a second-order quadratic upwind interpolation of convective kinematics scheme for the convection terms and the semi-implicit method for pressure-linked equations pressure correction algorithm were used.

Findings

The results indicate that the variation of the area-averaged Nusselt number strongly depends on the Reynolds number. On the contrary, the effect of cylinders’ space on heat transfer was found to be nearly negligible for Re < 460. It is also observed that steady state flow and heat transfer shift to periodical oscillation, and ultimately chaotic oscillation in non-dimensional cylinders distance of 0.1; however the sequence of appearing this route is completely different for higher cylinder spaces.

Research limitations/implications

Reynolds numbers between 380 and 550 and dimensionless horizontal distances of cylinders 0.1, 0.2 and 0.3.

Originality/value

Comprehensive knowledge of the effect of tube arrays flow regime on each other and in turn, heat transfer among them. Better understanding of convective heat transfer around an array of horizontal cylinders compared with from those around a single cylinder because of the mutual interaction of the buoyant plumes generated by the cylinders. Time-dependent phenomena of the problem including periodical oscillation or chaotic features.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 26 no. 1
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 12 June 2009

Bin Xiao and Yuwen Zhang

The purpose of this paper is to investigate the geometric effects and pulsatile characteristics during the stenotic flows in tapering arteries.

Abstract

Purpose

The purpose of this paper is to investigate the geometric effects and pulsatile characteristics during the stenotic flows in tapering arteries.

Design/methodology/approach

The low Reynolds number k − ω turbulence model is applied to describe the stenotic flows in the tapering arteries in this paper. The results are divided into two sections. The first section characterizes the geometric effects on the turbulent flow under steady condition. The second section illustrates the key physiological parameters including the pressure drop and wall stress during the periodic cycle of the pulsatile flow in the arteries.

Findings

The tapering and stenoses severity intensify the turbulent flow and stretch the recirculation zones in the turbulent arterial flow. The wall shear stress, pressure drop and velocity vary most intensively at the peak phase during the periodic cycle of the pulsatile turbulent flow.

Originality/value

This paper provides a comprehensive understanding of the spatial‐temporal fluid dynamics involved in turbulent and transitional arterial flow with stenoses. The low Reynolds number k − ω turbulence model method is applied for the analyses of the geometric effects on the arterial flow and fluid feature during the periodic cycle.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 19 no. 5
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 1 August 2016

Zheng Li, Mo Yang and Yuwen Zhang

The purpose of this paper is to test an efficiency algorithm based on lattice Boltzmann method (LBM) and using it to analyze two-dimensional natural convection with low Prandtl…

Abstract

Purpose

The purpose of this paper is to test an efficiency algorithm based on lattice Boltzmann method (LBM) and using it to analyze two-dimensional natural convection with low Prandtl number.

Design/methodology/approach

Steady state or oscillatory results are obtained using double multiple-relaxation-time thermal LBM. The velocity and temperature fields are solved using D2Q9 and D2Q5 models, respectively.

Findings

With different Rayleigh number, the tested natural convection can either achieve to steady state or oscillatory. With fixed Rayleigh number, lower Prandtl number leads to a weaker convection effect, longer oscillation period and higher oscillation amplitude for the cases reaching oscillatory solutions. At fixed Prandtl number, higher Rayleigh number leads to a more notable convection effect and longer oscillation period.

Originality/value

Double multiple-relaxation-time thermal LBM is applied to simulate the low Prandtl number (0.001-0.01) fluid natural convection. Rayleigh number and Prandtl number effects are also investigated when the natural convection results oscillate.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 26 no. 6
Type: Research Article
ISSN: 0961-5539

Keywords

Open Access
Article
Publication date: 9 December 2022

Pinjie Xie, Baolin Sun, Li Liu, Yuwen Xie, Fan Yang and Rong Zhang

To cope with the severe situation of the global climate, China proposed the “30 60” dual-carbon strategic goal. Based on this background, the purpose of this paper is to…

Abstract

Purpose

To cope with the severe situation of the global climate, China proposed the “30 60” dual-carbon strategic goal. Based on this background, the purpose of this paper is to investigate scientifically and reasonably the interprovincial pattern of China’s power carbon emission intensity and further explore the causes of differences on this basis.

Design/methodology/approach

Considering the principle of “shared but differentiated responsibilities,” this study measures the carbon emissions within the power industry from 1997 to 2019 scientifically, via the panel data of 30 provinces in China. The power carbon emission intensity is chosen as the indicator. Using the Dagum Gini coefficient to explore regional differences and their causes.

Findings

The results of this paper show that, first, China’s carbon emission intensity from the power industry overall is significantly different. From the perspective of geospatial distribution, the three regions have unbalanced characteristics. Second, according to the decomposition results of the Gini coefficient, the overall difference in power carbon emission intensity is generally expanding. The geospatial and economic development levels are examined separately. The gaps between the eastern and economically developed regions are the smallest, and the regional differences are the source of the overall disparity.

Research limitations/implications

Further exploring the causes of differences on this basis is crucial for relevant departments to formulate differentiated energy conservation and emission reduction policies. This study provides direction for analyzing the green and low carbon development of China’s power industry.

Practical implications

As an economic indicator of green and low-carbon development, CO2 intensity of power industry can directly reflect the dependence of economic growth on the high emission of electricity and energy. and further exploring the causes of differences on this basis is crucial for relevant departments to formulate differentiated energy conservation and emission reduction policies.

Social implications

For a long time, with the rapid economic development, resulting in the unresolved contradiction between low energy efficiency and high carbon emissions. To this end, scientifically and reasonably investigating the interprovincial pattern of China’s power carbon emission intensity, and further exploring the causes of differences on this basis, is crucial for relevant departments to formulate differentiated energy conservation and emission reduction policies.

Originality/value

Third, considering the influence of spatial factors on the convergence of power carbon emission intensity, a variety of different spatial weight matrices are selected. Based on the β-convergence theory from both absolute and conditional perspectives, we dig deeper into the spatial convergence of electricity carbon emission intensity across the country and the three regions.

Details

International Journal of Climate Change Strategies and Management, vol. 15 no. 2
Type: Research Article
ISSN: 1756-8692

Keywords

Article
Publication date: 21 August 2018

Bo Li, Bo Yuan, Shuai Tang, Yuwen Mao, Dongmei Zhang, Changyun Huang and Bilian Tan

This paper aims to investigate weight-climbing assistance strategy for the biomechanical design of passive knee-assisting exoskeleton (PKAExo) and evaluate a designed PKAExo which…

Abstract

Purpose

This paper aims to investigate weight-climbing assistance strategy for the biomechanical design of passive knee-assisting exoskeleton (PKAExo) and evaluate a designed PKAExo which stores energy when the knee joint flexes and releases the energy to assist ascending when the knee joint extends.

Design/methodology/approach

The authors constructed theoretic modeling of human weight-climbing to analyze characteristics of knee angle and moment. They then conducted camera-based movement analysis, muscle strength and endurance tests and surface electromyography (sEMG) measures to verify the relationship of knee angle and moment with both stair height and load weight. Afterwards, the authors proposed an assistant strategy for passive knee assistance, then gave out designed PKAExo and conducted mechanical experiment to test the knee-assisting torque. Finally, the authors conducted comparison experiment based on measuring the sEMG signals of knee extensor to verify the assistance effect of the PKAExo for weight-climbing.

Findings

The knee extensor produces the maximum force during weight-climbing, and the muscle force provided by knee extensor has significant increasing rate along with the stair height. Thus, the assistance torque of PKAExo is designed to increase nonlinearly along with increasing knee angle. It stores energy when knee flexes and assists when knee extends. Both the mechanical experiment and comparison experiment have demonstrated that the PKAExo is able to provide nonlinear assistance torque for weight-climbing, thus decreasing the average maximum load of knee extensor by about 21 per cent, reducing muscle fatigue and enhancing wearer’s weight-climbing ability.

Originality/value

The authors construct theoretic maximum force model produced by knee extensor for weight-climbing in static situation and conduct a series of experiments to verify and revise the model, which is the fundamental reference for knee-assisting mechanism designed for weight-climbing. The authors have also provided and validated an assistant strategy and the mechanism based on the biomechanical analysis, which aims to translate wearer’s energy-providing mode form high load to mid-low load by storing energy when knee flexes and assisting when knee extends. The PKAExo decreases the maximum load of knee extensor, reduces muscle fatigue and helps people to easily climb with load.

Details

Industrial Robot: An International Journal, vol. 45 no. 4
Type: Research Article
ISSN: 0143-991X

Keywords

Article
Publication date: 5 May 2021

Meng Wang, Yuwen Hua, Honglei Lia Sun, Ya Chen and Linping Jiang

This study aims to reveal the influencing factors of user churn behavior and explore how these factors influence user churn behavior of rural public digital cultural services…

Abstract

Purpose

This study aims to reveal the influencing factors of user churn behavior and explore how these factors influence user churn behavior of rural public digital cultural services (RPDCS), and then, to provide the avoidance strategies for user churn behavior of RPDCS.

Design/methodology/approach

Combined with the stimulus–organism–response theory and cognitive load theory, this study constructed a mixed model of user churn behavior. Data collected through online and offline questionnaire survey were tested using the partial least squares structural equation modeling approach, and finally, the authors proposed a user churn behavior model of RPDCS.

Findings

The results indicate that the environmental stimulus factors of RPDCS affected user churn behavior via user organism factors. This study suggests that administrators should pay more attention to the information demand of users and strengthen the effective supply of RPDCS. Meanwhile, it is necessary to improve the information literacy of rural users to restrain the user churn behavior and improve the effectiveness of RPDCS.

Originality/value

The research findings on the influencing factors of user churn behavior shed light on the user churn behavior in public digital cultural services, add new knowledge to the construction of the public cultural services system and provide empirical evidence for how to improve the utilization and effectiveness of RPDCS.

Details

Library Hi Tech, vol. 40 no. 5
Type: Research Article
ISSN: 0737-8831

Keywords

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