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1 – 10 of 25
Article
Publication date: 9 May 2022

Yanhong Yan, Xiaocui Yan, Chengwen Yang, Yanfei Zhou, Zhining Jia and Caizhe Hao

The purpose of this study is to improve the dispersion of nanoserpentine modified with OA, KH550 and KH550/oleic acid in lubricating oil. The main aims are to analyze the…

Abstract

Purpose

The purpose of this study is to improve the dispersion of nanoserpentine modified with OA, KH550 and KH550/oleic acid in lubricating oil. The main aims are to analyze the influence of the dispersion and stability of nanoserpentine modified by different modifiers on the friction properties of lubricating oil.

Design/methodology/approach

The nanoserpentine particles obtained by ball-milling were modified by silane coupling agent KH550, OA and KH550/OA, respectively. The dispersity and stability of nanoserpentine in base lubricating oil were characterized by the absorbance value method, centrifuge precipitation rate method and static observation method. The MMU-5G screen display friction and wear tester was used to evaluate the tribological properties of C45E4/C45E4 friction pairs in corresponding lubricating oils. The surface morphology of the friction pairs was observed by scanning electron microscopy and energy dispersive spectroscopy.

Findings

The results showed that the dispersity and stability of nanoserpentine particles in lubricating oil were best modified by OA, followed by the KH550/OA and finally, the KH550. Nanoserpentine particles modified with oleic acid showed optimum tribological properties as lubricant additives.

Originality/value

This study can improve the dispersion stability of nanoserpentine particles in lubricating oil, increasing the antiwear and antifriction performance of lubricating oil, which has great significance in economic and military aspects.

Details

Industrial Lubrication and Tribology, vol. 74 no. 6
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 18 January 2022

Yanhong Yan, Chengwen Yang, Yanfei Zhou, Wenbin Dong, Pengjuan Yan and Zhining Jia

Previously, the effect of pore-forming agents on the properties of pore size and morphology was studied. In this paper, we determine the optimal combination of parameters by…

Abstract

Purpose

Previously, the effect of pore-forming agents on the properties of pore size and morphology was studied. In this paper, we determine the optimal combination of parameters by tensile strength and perform tribological tests with optimal combination of parameters.

Design/methodology/approach

In this paper, porous polyimide (PI) materials were fabricated using vacuum hot molding technology. The orthogonal experiment was designed to test the mechanical properties of porous PI materials with the process parameters and the content of pore-forming agent as the changing factors. The porous PI oil-bearing materials were obtained by vacuum immersion, and tribological test were carried out.

Findings

The results showed that porous PI oil-bearing materials are suitable for low-speed and low-load conditions. The actual value of the friction coefficient basically match with the theoretical value of the regression analysis, and the errors of the friction coefficient are within 10% and 3%, respectively, which proves that the method used in the study is feasible for the friction coefficient prediction.

Originality/value

In this paper, we have produced a new porous oil-bearing material with good tribological properties. This study can effectively predict the friction coefficient of PI porous material.

Details

Industrial Lubrication and Tribology, vol. 74 no. 2
Type: Research Article
ISSN: 0036-8792

Keywords

Abstract

Details

Population Change, Labor Markets and Sustainable Growth: Towards a New Economic Paradigm
Type: Book
ISBN: 978-0-44453-051-6

Article
Publication date: 27 January 2020

Yongxin Zhou, Qian Li, Zhiguo Xing, Renze Zhou, Zhenhua Huang, Yanfei Huang and Weiling Guo

This paper aims to investigate the effect of aluminum addition on the microstructure and mechanical properties of Mg-8Gd-4Y-1Zn alloy.

Abstract

Purpose

This paper aims to investigate the effect of aluminum addition on the microstructure and mechanical properties of Mg-8Gd-4Y-1Zn alloy.

Design/methodology/approach

Mg-8Gd-4Y-1Zn-xAl (x = 0, 0.5, 1.0, 1.5, 2.0 Wt.%) alloys were prepared by the conventional gravity casting technology, and then microstructures, phase composition and mechanical properties were investigated by material characterization method, systematically.

Findings

Results show that the as-cast microstructure of Mg-8Gd-4Y-1Zn alloy mainly consists of a-Mg matrix as well as Mg12REZn (18 R LPSO structure), and island-like Mg3(RE, Zn) phase is distributed at the grain boundary. The addition of a small amount of Al (0.5 Wt.%) can decrease the content of island-like Mg3(RE, Zn) phase, but significantly increase the content of long-period stacking ordered (LPSO) structure, resulting in the improvement of both tensile strength and elongation of Mg-8Gd-4Y-1Zn alloy. However, the addition of excessive Al will consume Re element and decrease the amount of LPSO structure, leading to the decrease of tensile properties. When the content of Al is 0.5 Wt.%, the tensile strength and elongation are 225 MPa and 9.0% of Mg-8Gd-4Y-1Zn alloy, which are 14% and 29% higher than that of Mg-8Gd-4Y-1Zn alloy, respectively.

Originality/value

Adding aluminum to Mg-8Gd-4Y-1Zn alloy strengthens its mechanical properties. And the effect of Al content on the alloy strengthening. The formation mechanism of LPSO structure with different aluminum content was revealed.

Details

Anti-Corrosion Methods and Materials, vol. 67 no. 1
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 27 January 2020

Renze Zhou, Zhiguo Xing, Haidou Wang, Zhongyu Piao, Yanfei Huang, Weiling Guo and Runbo Ma

With the development of deep learning-based analytical techniques, increased research has focused on fatigue data analysis methods based on deep learning, which are gaining in…

358

Abstract

Purpose

With the development of deep learning-based analytical techniques, increased research has focused on fatigue data analysis methods based on deep learning, which are gaining in popularity. However, the application of deep neural networks in the material science domain is mainly inhibited by data availability. In this paper, to overcome the difficulty of multifactor fatigue life prediction with small data sets,

Design/methodology/approach

A multiple neural network ensemble (MNNE) is used, and an MNNE with a general and flexible explicit function is developed to accurately quantify the complicated relationships hidden in multivariable data sets. Moreover, a variational autoencoder-based data generator is trained with small sample sets to expand the size of the training data set. A comparative study involving the proposed method and traditional models is performed. In addition, a filtering rule based on the R2 score is proposed and applied in the training process of the MNNE, and this approach has a beneficial effect on the prediction accuracy and generalization ability.

Findings

A comparative study involving the proposed method and traditional models is performed. The comparative experiment confirms that the use of hybrid data can improve the accuracy and generalization ability of the deep neural network and that the MNNE outperforms support vector machines, multilayer perceptron and deep neural network models based on the goodness of fit and robustness in the small sample case.

Practical implications

The experimental results imply that the proposed algorithm is a sophisticated and promising multivariate method for predicting the contact fatigue life of a coating when data availability is limited.

Originality/value

A data generated model based on variational autoencoder was used to make up lack of data. An MNNE method was proposed to apply in the small data case of fatigue life prediction.

Details

Anti-Corrosion Methods and Materials, vol. 67 no. 1
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 15 March 2024

Xingxin Li, Yanfei Wang, Yu Zhu and Lixun Zheng

Drawing on affective events theory (AET), this study aims to investigate how and when leader voice solicitation affects employees’ innovative behavior. Specifically, this study…

Abstract

Purpose

Drawing on affective events theory (AET), this study aims to investigate how and when leader voice solicitation affects employees’ innovative behavior. Specifically, this study proposes that leader voice solicitation evokes employees’ feelings of pride, which subsequently motivate employees’ innovative behavior. Moreover, collectivism orientation plays a moderating role in this process.

Design/methodology/approach

This study collected 251 supervisor–subordinate dyadic data in two phases and employed structural equational modeling (SEM) to test the hypotheses.

Findings

The results revealed that employees’ feelings of pride mediate the positive relationship between leader voice solicitation and employees’ innovative behavior. Collectivism orientation intensifies the mediated relationship.

Originality/value

This study extends the potential outcome variables of leader voice solicitation. Moreover, it introduces a novel theoretical perspective to explore the impact of leader voice solicitation on employees. Importantly, this study examines the mediating effect of pride and the moderating effect of collectivism orientation, deepening the understanding of how and when leader voice solicitation affects innovative behavior.

Details

Leadership & Organization Development Journal, vol. 45 no. 4
Type: Research Article
ISSN: 0143-7739

Keywords

Article
Publication date: 20 July 2021

Guohua He, Yanfei Wang, Xinnian Zheng, Zisheng Guo and Yu Zhu

This study explores how paternalistic leadership (PL) influences Chinese expatriates' work engagement in a cross-cultural context, and examines how expatriates' cross-cultural…

1135

Abstract

Purpose

This study explores how paternalistic leadership (PL) influences Chinese expatriates' work engagement in a cross-cultural context, and examines how expatriates' cross-cultural adaptability sets a boundary condition for this relationship.

Design/methodology/approach

Data were collected from two-wave surveys of 82 supervisors and 318 Chinese expatriate teachers from 57 Confucius Institutes in 18 countries. Structural equation modeling was used to test the hypothesized relationships.

Findings

Benevolent and moral leadership as job resources are negatively related to work–family conflict (WFC), whereas the job demand of authoritarian leadership positively relates to WFC. Further, WFC mediates the effect of PL styles on Chinese expatriates' work engagement. Cross-cultural adaptability moderates the negative relationship between WFC and work engagement, and the indirect effect of PL styles on work engagement through WFC.

Practical implications

Organizations should consider WFC an important intervening mechanism linking PL and Chinese expatriates' work engagement. Cross-cultural organizations can mitigate the negative impact of WFC on work engagement by enhancing expatriates' cross-cultural adaptability.

Originality/value

This study is the first to examine the PL–work engagement relationship via a work–family interface, which contributes to integrating leadership and work–family outcomes. It enriches research on the JD-R model by showing that job resources and job demands affect employee outcomes through the mediation of stressors. Furthermore, this study identifies a new personal resource by examining cross-cultural adaptability's moderating role.

Details

International Journal of Manpower, vol. 43 no. 4
Type: Research Article
ISSN: 0143-7720

Keywords

Article
Publication date: 11 January 2022

Lixun Zheng, Yanfei Wang, Zisheng Guo and Yu Zhu

The purpose of this paper is to examine the impact of managerial coaching (MC) on employee creative performance (CP) based on the knowledge transfer theory and the roles of…

1150

Abstract

Purpose

The purpose of this paper is to examine the impact of managerial coaching (MC) on employee creative performance (CP) based on the knowledge transfer theory and the roles of creative process engagement (CPE) and climate for innovation (IC) in the relationship between MC and CP.

Design/methodology/approach

A moderated mediation model was developed and tested on a dyadic sample of 74 leaders and 292 employees working in South China firms.

Findings

The results show that CPE mediates the relationship between MC and CP and IC amplifies the indirect relationship between MC and CP via CPE.

Originality/value

This research contributes to the MC and innovation literature by clarifying the linking role of engagement in transferring MC into employees' CP from a knowledge transfer perspective and identifies the critical role of IC in effectuating the impact of MC on CP.

Details

Leadership & Organization Development Journal, vol. 43 no. 2
Type: Research Article
ISSN: 0143-7739

Keywords

Article
Publication date: 16 May 2018

Yanfei Wang, Jieqiong Liu and Yu Zhu

The purpose of this paper is to develop a moderated mediation model to examine the roles that psychological capital (PsyCap) and growth need strength may play in the relationship…

2668

Abstract

Purpose

The purpose of this paper is to develop a moderated mediation model to examine the roles that psychological capital (PsyCap) and growth need strength may play in the relationship between humble leader behaviors and follower creativity.

Design/methodology/approach

Data were collected from a three-wave survey study with a sample of 165 matched leader-follower questionnaires in China. Multiple regression analyses, moderated regression analysis and bootstrapping analysis were used to test the hypotheses.

Findings

The results show that humble leader behaviors positively influence follower creativity, PsyCap mediates this influence and growth need strength not only moderates the relationship between humble leader behaviors and PsyCap, but also amplifies the indirect relationship between humble leader behaviors and follower creativity via PsyCap.

Research limitations/implications

Common method bias may still exit, although the measures of research variables were gathered from different sources and with time separation. Additionally, this study is conducted in a single cultural context, which may raise the question about the generalizability of our findings to other cultural contexts.

Originality/value

The primary contribution is building and examining a conceptual model that focuses on the potential effect of humble leader behaviors on follower creativity. Additionally, by confirming the mediating role of PsyCap, the research further uncovers why followers under humble leader behaviors are more likely to engage in creativity, and the moderating role of growth need strength found in this study also offers additional insight into that followers may differ in the degree to which they are receptive to leader effect.

Details

Leadership & Organization Development Journal, vol. 39 no. 4
Type: Research Article
ISSN: 0143-7739

Keywords

Article
Publication date: 17 April 2023

Yukun Wei, Leyang Dai, YanFei Fang, Chen Xing Sheng and Xiang Rao

The purpose of this paper is to enhance the characteristics of TiO2 nanoparticles (NPs). Because these NPs stick together easily and are difficult to distribute evenly, they…

Abstract

Purpose

The purpose of this paper is to enhance the characteristics of TiO2 nanoparticles (NPs). Because these NPs stick together easily and are difficult to distribute evenly, they cannot be used extensively in lubricating oils. Altering TiO2 was recommended as an alternate way for making NPs simpler to disperse.

Design/methodology/approach

Through dielectric barrier discharge plasma (DBDP)-assisted ball mill diagnostics and modeling of molecular dynamics, TiO2@PEG-400 NPs were produced using the DBDP-assisted ball mill. The NPs’ microstructure was examined using FESEM, TEM, XRD, FT-IR and TG-DSC. Using the CFT-1 reciprocating friction tester, the tribological properties of TiO2@PEG-400 NPs as base oil additives were studied. EDS and XPS were used to examine the surface wear of the friction pair.

Findings

Tribological properties of the modified NPs are vastly superior to those of the original NPs, and the lipophilicity value of TiO2 NPs was improved by 200%. It was determined through tribological testing that TiO2@PEG-400’s exceptional performance might be attributable to a chemical reaction film made up of TiO2, Fe2O3, iron oxide and other organic chemicals.

Originality/value

This work describes an approach for preventing the aggregation of TiO2 NPs by coating their surface with PEG-400. In addition, the prepared NPs can enhance the tribological performance of lubricating oil. This low-cost, high-performance lubricant additive has tremendous promise for usage in marine engines to minimize operating costs while preserving navigational safety.

Details

Industrial Lubrication and Tribology, vol. 75 no. 4
Type: Research Article
ISSN: 0036-8792

Keywords

1 – 10 of 25