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Article
Publication date: 16 November 2018

Soheil Mohajerani, Duruo Huang, Gang Wang, Seyed-Mohammad Esmaeil Jalali and Seyed Rahman Torabi

This study aims to develop an efficient algorithm for generation of conforming mesh for seepage analysis through 3D discrete fracture networks (DFN).

Abstract

Purpose

This study aims to develop an efficient algorithm for generation of conforming mesh for seepage analysis through 3D discrete fracture networks (DFN).

Design/methodology/approach

The algorithm is developed based on a refined conforming Delaunay triangulation scheme, which is then validated using analytical solutions. The algorithm is well able to meet the challenge of meshing complex geometry of DFNs.

Findings

A series of sensitivity analysis have been performed to evaluate the effect of meshing parameters on steady state solution of Darcy flow using a finite element scheme. The results show that an optimized minimum internal angle of meshing elements should be predetermined to guarantee termination of the algorithm.

Originality/value

The developed algorithm is computationally efficient, fast and is of low cost. Furthermore, it never changes the geometrical structure and connectivity pattern of the DFN.

Details

Engineering Computations, vol. 35 no. 8
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 8 August 2018

Gang Wang, Xiaohui Liu, Changhong Mi, Huijuan Fan, Bo Xu and Xuefeng Bai

The purpose of this study was to investigate the microstructural evolution and hydrolytic stability of poly(phenylborosiloxane) (PPhBS) to further use and develop the…

Abstract

Purpose

The purpose of this study was to investigate the microstructural evolution and hydrolytic stability of poly(phenylborosiloxane) (PPhBS) to further use and develop the oligomers as heat-resistant modifiers.

Design/methodology/approach

PPhBS was synthesized by direct co-condensation of boric acid (BA) and phenyltriethoxysilane (PTEOS). The structural evolution of PPhBS at high temperature was investigated by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), differential thermal analysis (DTA), in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and 29Si nuclear magnetic resonance (NMR) spectroscopy. In addition, the change in the morphology of the PPhBS powder was examined to demonstrate the evolution of the chemical bonds, and the hydrolytic stability of PPhBS was investigated by a combination of X-ray diffraction (XRD) analysis, measurement of the mass loss in water and FTIR spectroscopy.

Findings

The results revealed that a cross-linking network was gradually formed with increasing temperature through the condensation of the residual hydroxyl groups in PPhBS, and the Si-OH and B-OH bonds remained even at a high temperature of 450°C. Furthermore, heat treatment improved the hydrolytic stability of the oligomer. The hydrolysis of the B-O-B bonds in PPhBS was reversible, whereas the Si-O-Si and Si-O-B bonds were highly resistant to hydrolysis.

Practical implications

The prepared PPhBS can be used as a heat-resistant modifier in adhesives, sealants, coatings and composite matrices.

Originality/value

Investigation of the structural evolution of a polyborosiloxane at high temperature by DRIFTS is a novel approach that avoided interference from moisture in the air. The insoluble mass fraction and the FTIR spectrum of PPhBS washed with water were used to investigate the hydrolytic stability of PPhBS.

Details

Pigment & Resin Technology, vol. 47 no. 4
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 12 March 2018

Jibao Gu, Gang Wang, Hefu Liu, Derun Song and Changqing He

The present study aims to examine how and when authoritarian leadership affects employee creativity. Based on social exchange theory and team identification literature…

Abstract

Purpose

The present study aims to examine how and when authoritarian leadership affects employee creativity. Based on social exchange theory and team identification literature, the present research attempts to simultaneously explore how leader–member exchange (LMX) and team identification serve as two important mediating processes in the relationship between authoritarian leadership and employee creativity. Furthermore, this research uncovers the mechanism under which conditions the effects of authoritarian leadership will be magnified or minimized.

Design/methodology/approach

A survey has been conducted in China by using a questionnaire to collect data. The study sample consisted of 325 employees. LISREL 8.7 and SPSS 18.0 were used to test the mediating and moderating effects, respectively.

Findings

Results from 325 employees revealed that both LMX and team identification mediated the negative relationships between authoritarian leadership and employee creativity. Specifically, the relationship between two mediators was that LMX was positively related to team identification. In addition, the relationship between authoritarian leaderships and LMX and team identification was moderated by power distance, such that the negative relationships will be weaker with high power distance and stronger with low power distance.

Practical implications

First, firms and managers should recognize and take actions to reduce the negative effects of authoritarian leadership, such as effective selection system and interventional mechanisms because authoritarian leadership is important in influencing employee creativity. Second, managers are suggested to take specific actions, such as increasing communications and team-building activities, to promote LMX and team identification, thereby enhancing employee creativity. Third, managers should engage in behaviors that motivate employee creativity, such as empowerment behaviors, other than authoritarian leadership, when the employee has low power distance.

Originality/value

The primary contribution of this research is that two psychological processes (i.e. LMX and team identification) have been identified through which authoritarian leadership is related to employee creativity. Meanwhile, this study explores the relationship between LMX and team identification. Moreover, the current research deepens our understanding of power distance by empirically examining the moderating effect of power distance. Overall, the findings extend our understanding about the relationship between authoritarian leadership and employee creativity and contribute to literature on authoritarian leadership and creativity.

Details

Chinese Management Studies, vol. 12 no. 2
Type: Research Article
ISSN: 1750-614X

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Article
Publication date: 30 April 2020

Gang Wang, Yue Zhang, Chen Gao, GuangTao Xu and MingHao Zhao

The purpose of this paper is to investigate, the effects of residual stress and microstructure on the corrosion behaviour of carburised 18CrNiMo7-6 steel in a 3.5% NaCl…

Abstract

Purpose

The purpose of this paper is to investigate, the effects of residual stress and microstructure on the corrosion behaviour of carburised 18CrNiMo7-6 steel in a 3.5% NaCl aqueous solution.

Design/methodology/approach

The electrochemical tests were conducted using an electrochemical workstation with a three-electrode system in a 3.5% NaCl aqueous solution, the residual stress of each working face was measured by a high-speed residual stress analyser, and microstructure of different carburised layers were observed scanning electron microscopy. Finally, the effect of carbon content, microstructure and residual stress on the corrosion behaviour of the steel was discussed.

Findings

The results showed that the residual compressive stress in the carburised layer initially increased and subsequently decreased with increasing depth of the carburised layer, reaching stability in the matrix layer. The electrochemical tests before and after stress reduction showed that the electrochemical impedance and the electrochemical potential increased with the reduction of residual compressive stress.

Originality/value

The residual compressive stress in the carburised layer initially increases and subsequently decreases with increasing carburised layer depth. The electrochemical impedance and the electrochemical potential increased with the reduction of residual compressive stress. The general relationship between electrochemical potential and residual stress was established.

Details

Anti-Corrosion Methods and Materials, vol. 67 no. 4
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 13 April 2020

Joshua C. Palmer, Yunhyung Chung, Youngkyun Park and Gang Wang

Drawing on broaden-and-build theory and promotion- and prevention-focus theory, the authors examined the role of positive and negative affectivity (PANA) on the riskiness…

Abstract

Purpose

Drawing on broaden-and-build theory and promotion- and prevention-focus theory, the authors examined the role of positive and negative affectivity (PANA) on the riskiness of investment decisions. The authors also examined the mediating impact of financial knowledge network intensity (i.e. the level of communication with financially literate others in employees' social network) on the PANA—riskiness of investment decisions relationship.

Design/methodology/approach

Study 1 used a sample of undergraduate students and operationalized risk using a hypothetical investment scenario. Study 2 replicated and extended the Study 1 findings using employees and operationalized risk using their real-world investment allocations.

Findings

Both Studies 1 and 2 provided support for the negative direct relationship between NA and the riskiness of investment decisions. Study 2 found PA was marginally positively related to the riskiness of investment decisions. Financial knowledge network intensity mediated the relationship between NA and the riskiness of investment decisions in Study 2.

Research limitations/implications

The findings suggest that employees who see the world in a generally negative light tended to have weaker financial knowledge networks, and this may be one mechanism that explains why they make low-risk investments.

Practical implications

Financial knowledge networks can provide access to critical information regarding investment opportunities. Socialization training or social mixers can be used to help employees build and improve their financial knowledge networks.

Originality/value

The authors integrate the research on PANA, social networks, and investment decisions to illuminate the social network processes that explain how affectivity impacts the riskiness of retirement investment decisions.

Details

Personnel Review, vol. 49 no. 9
Type: Research Article
ISSN: 0048-3486

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Article
Publication date: 5 March 2018

She Li, Xiangyang Cui and Gang Wang

The purpose of this paper is to apply the element decomposition method (EDM) in the study of the bending and vibration properties of plate and shell.

Abstract

Purpose

The purpose of this paper is to apply the element decomposition method (EDM) in the study of the bending and vibration properties of plate and shell.

Design/methodology/approach

In the present method, each quadrilateral element is first divided into four sub-triangular cells, and the local strains are obtained in those sub-triangles based on linear interpolation. The whole strain filed is formulated through a weighted averaging operation of local strains, implying that only one integration point is adopted to construct the stiffness matrix. To reduce the instability of one-point integration and increase the accuracy of the present method, a stabilization item of the stiffness matrix is formulated by variance of the local strains. A mixed interpolated tensorial components (MITC) method is used in eliminating the shear locking phenomenon.

Findings

The novel EDM based on linear interpolation is effective in bending and vibration analyses of plate and shell, and the present method used in practical problems is reliable for static and free vibration analysis.

Originality/value

This method eliminated the instability of one-point integration and increased the accuracy by a stabilization item and performed stably in engineering analysis including large-scale problems of vehicle components.

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Article
Publication date: 2 May 2017

Bing Liang, Jiao Lv, Gang Wang and Tsubaki Noritatsu

The purpose of this paper is to prepare a novel halogen-free intumescent flame retardant (IFR) BHPPODC (benzene hydroquinone phosphorous oxy dichloride cyanuric chloride…

Abstract

Purpose

The purpose of this paper is to prepare a novel halogen-free intumescent flame retardant (IFR) BHPPODC (benzene hydroquinone phosphorous oxy dichloride cyanuric chloride) for application to epoxy resin (EP) and study their mechanical and flame-retardant performance.

Design/methodology/approach

The IFR was synthesised by phenylphosphonic dichloride, hydroquinone and cyanuric chloride via solvent reaction, and the structure was fully characterised by proton nuclear magnetic resonance (1H-NMR), mass spectrometry (MS) and Fourier transform infrared (FT-IR) spectroscopy. The thermal stability, mechanical and flame properties and morphology of the char layer of the flame-retardant EP was investigated by using thermogravimetric analysis (TGA), tensile and Charpy impact tests, limiting oxygen index (LOI) and vertical burning test (UL-94) and scanning electron microscopy (SEM).

Findings

Results of the LOI indicated that the halogen-free flame retardant as an additive exhibits very good flame-retardant effects. The results showed that the addition of IFR improved the flame resistance properties of epoxies resin composites, and the residual char ratio at 800°C significantly increased.

Research limitations/implications

The IFR can be prepared successfully and can improve the flame-retardant performance.

Practical implications

This contribution can provide a high flame retardant performance and has minimal impact on the mechanical performance of the BHPPODC/EP composition.

Originality/value

This study showed that flame-retardant BHPPODC has an effective flame effect under optimal conditions. When the 12 Wt.% IFR was added to the EP, the LOI was 29.1 and the UL-94 rank can reach V-0 rank, the tensile strength was 83.86 MPa and the impact strength was 8.82 kJ/m2.

Details

Pigment & Resin Technology, vol. 46 no. 3
Type: Research Article
ISSN: 0369-9420

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Book part
Publication date: 8 October 2020

Jeremy D. Mackey, Charn P. McAllister, Liam P. Maher and Gang Wang

Recently, there has been an increase in the number and type of studies in the organizational sciences that examine curvilinear relationships. These studies are important…

Abstract

Recently, there has been an increase in the number and type of studies in the organizational sciences that examine curvilinear relationships. These studies are important because some relationships have context-specific inflection points that alter their magnitude and/or direction. Although some scholars have utilized basic techniques to make meta-analytic inferences about curvilinear effects with the limited information available about them, there is still a tremendous opportunity to advance our knowledge by utilizing rigorous techniques to meta-analytically examine curvilinear effects. In a recent study, we used a novel meta-analytic approach in an effort to comprehensively examine curvilinear relationships between destructive leadership and followers' workplace outcomes. The purpose of this chapter is to provide an actionable guide for conducting curvilinear meta-analyses by describing the meta-analytic techniques we used in our recent study. Our contributions include a detailed guide for conducting curvilinear meta-analyses, the useful context we provide to facilitate its implementation, and our identification of opportunities for scholars to leverage our technique in future studies to generate nuanced knowledge that can advance their fields.

Details

Advancing Methodological Thought and Practice
Type: Book
ISBN: 978-1-80043-079-2

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Book part
Publication date: 17 July 2014

James Mandigo, John Corlett, Pedro Ticas and Ruben Vasquez

El Salvador’s youth have faced a climate of violence for decades. Schools have been identified as the most cost-effective ways to help students develop the life skills…

Abstract

Purpose

El Salvador’s youth have faced a climate of violence for decades. Schools have been identified as the most cost-effective ways to help students develop the life skills they need to prevent violence. This study examined the potential role of a physical education (PE) program taught by some of the first Salvadoran teachers to be trained to foster life skills through PE within schools.

Design/methodology/approach

Fourteen schools that had hired a PE teacher trained in life skills-based PE volunteered to participate in the study. Semi-structured interviews with the school director, PE teacher, and a focus group of students at each school were conducted.

Findings

Interviews were content analyzed and potential themes were initially placed into one of three life skills categories using a deductive analysis based upon the World Health Organization’s (WHO) (2002) three categories of life skills: (i) Coping and Self-Management; (ii) Communication and Interpersonal; (iii) Decision Making/Problem Solving. Then, using an inductive analysis, various themes within each life skills category were identified. The findings revealed that participants in the study identified the role that PE provides in developing life skills in each of the three categories and many identified the importance of these life skills to prevent violence both in and out of schools.

Social implications

Findings from this study highlight the important role that schools play in the development of life skills and the prevention of youth violence. PE in particular offers a promising approach due to its applied nature and opportunity for students to learn through doing and the application of life skills in a safe manner. The findings also support the importance of trained PE teachers to deliver such programs.

Originality/value

Central America has and continues to be a region with high levels of youth violence. Given that PE is a mandatory school subject in Salvadoran schools (and in other Central American countries), shifting the focus toward a life skills-based approach to PE offers educators an opportunity to address the country’s number one public health concern which is youth violence. To our knowledge, this is the first study of its kind in El Salvador to explore the role of PE as it relates to youth violence and can help in future curricular revisions in schools and the development of degree programs at local universities.

Details

Sport, Social Development and Peace
Type: Book
ISBN: 978-1-78350-885-3

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Article
Publication date: 11 March 2014

Wei Wang, Gang Wang and Chao Yun

Calibrating kinematic parameters is one of the efficient ways to improve the robot's positioning accuracy. A method based on the product-of-exponential (POE) formula to…

Abstract

Purpose

Calibrating kinematic parameters is one of the efficient ways to improve the robot's positioning accuracy. A method based on the product-of-exponential (POE) formula to calibrate the kinematic parameters of serial industrial robots is proposed. The paper aims to discuss these issues.

Design/methodology/approach

The forward kinematics is established, and the general positioning error model is deduced in an explicit expression. A simplified model of robot's positioning error is established as both the error of reference configuration and the error of rigid displacement of the base coordinating system with respect to the measuring coordinating system are equivalently transferred to the zero position errors of the robot's joints. A practical calibration model is forwarded only requiring 3D measuring based on least-squares algorithm. The calibration system and strategy for calibrating kinematic parameters are designed.

Findings

By the two geometrical constrains between the twist coordinates, each joint twist only has four independent coordinates. Due to the equivalent error model, the zero position error of each joint can cover the error of reference configuration and rigid displacement of the robot base coordinating system with respect to the measuring coordinating system. The appropriate number of independent kinematic parameters of each joint to be calibrated is five.

Originality/value

It is proved by a group of calibration experiments that the calibration method is well conditioned and can be used to promote the level of absolute error of end effector of industrial robot to 2.2 mm.

Details

Industrial Robot: An International Journal, vol. 41 no. 2
Type: Research Article
ISSN: 0143-991X

Keywords

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