Zhicai Du, Qiang He, Hengcheng Wan, Lei Zhang, Zehua Xu, Yuan Xu and Guotao Li
This paper aims to improve the tribological properties of lithium complex greases using nanoparticles to investigate the tribological behavior of single additives (nano-TiO2 or…
Abstract
Purpose
This paper aims to improve the tribological properties of lithium complex greases using nanoparticles to investigate the tribological behavior of single additives (nano-TiO2 or nano-CeO2) and composite additives (nano-TiO2–CeO2) in lithium complex greases and to analyze the mechanism of their influence using a variety of characterization tools.
Design/methodology/approach
The morphology and microstructure of the nanoparticles were characterized by scanning electron microscopy and an X-ray diffractometer. The tribological properties of different nanoparticles, as well as compounded nanoparticles as greases, were evaluated. Average friction coefficients and wear diameters were analyzed. Scanning electron microscopy and three-dimensional topography were used to analyze the surface topography of worn steel balls. The elements present on the worn steel balls’ surface were analyzed using energy-dispersive spectroscopy and X-ray photoelectron spectroscopy.
Findings
The results showed that the coefficient of friction (COF) of grease with all three nanoparticles added was low. The grease-containing composite nanoparticles exhibited a lower COF and superior anti-wear properties. The sample displayed its optimal tribological performance when the ratio of TiO2 to CeO2 was 6:4, resulting in a 30.5% reduction in the COF and a 29.2% decrease in wear spot diameter compared to the original grease. Additionally, the roughness of the worn spot surface and the maximum depth of the wear mark were significantly reduced.
Originality/value
The main innovation of this study is the first mixing of nano-TiO2 and nano-CeO2 with different sizes and properties as compound lithium grease additives to significantly enhance the anti-wear and friction reduction properties of this grease. The results of friction experiments with a single additive are used as a basis to explore the synergistic lubrication mechanism of the compounded nanoparticles. This innovative approach provides a new reference and direction for future research and development of grease additives.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-09-2023-0291/
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Qian Li, Xunhua Guo, Xue Bai and Wei Xu
Considering the popularity and addictive attributes of microblogging, the purpose of this paper is to explore the key drivers of the microblogging addiction tendency, and to…
Abstract
Purpose
Considering the popularity and addictive attributes of microblogging, the purpose of this paper is to explore the key drivers of the microblogging addiction tendency, and to investigate the causal relationship between microblogging usage and addiction tendency through the lens of the uses and gratifications (U&G) theory.
Design/methodology/approach
By extending the U&G theory to accommodate the negative consequences of gratification, a research model that explains the relationships among microblogging use, gratification and addiction tendency was developed and empirically examined based on the data collected from 520 microblogging users in China.
Findings
The results showed that different types of microblogging use lead to different categories of gratification to different extents, while different categories of gratification play different roles in determining the level of addiction tendency. Specifically, the effect of content gratification on addiction is marginal, while social gratification has significant effects on all dimensions of addiction tendency.
Originality/value
The present study has both theoretical and practical implications. From a theoretical perspective, unlike many previous studies applied the U&G theory to explore the positive outcomes of media uses, this paper extends the U&G by including addiction tendency as a negative psychological outcome of U&G., resulting a research framework (use-gratification-addiction framework). Meanwhile, this paper contributes to the extending literature by examining the constructs of U&G at a granular level and investigated the causal relationship between “uses” and “gratifications.”
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Chunjiang Yang, Qinhai Ma and Ling Hu
The purpose of this paper is first, to overview the current research situation on job embeddedness (JE), including the theoretical underpinning of JE, the definition and…
Abstract
Purpose
The purpose of this paper is first, to overview the current research situation on job embeddedness (JE), including the theoretical underpinning of JE, the definition and dimensions of JE, its comparisons with similar constructs, and its global and composite measure; second, to intergrate the unfolding model, JE and image theory to better understand voluntary turnover – and indicate future research directions.
Design/methodology/approach
An extensive literature search covering several separate electronic databases, including ScienceDirect, EBSCO, Kluwer and Emerald, was conducted. Most of the articles can be acquired online from The University of California Riverside. The validity and reliability are compared between global and composite scales. The authors summarized and categorized the findings of current research.
Findings
JE can be differentiated from those similar constructs and measures already in the literature. Almost all of the studies on JE have found that it predicted voluntary turnover better than job attitudes and perceived ease of movement from traditional models of turnover. Along with extended research on it, JE was disaggregated into two major sub‐dimensions, namely, on‐the‐job and off‐the‐job embeddedness, and it has been extended to occupational and career level.
Research limitations/implications
In this paper, the authors use qualitative methods to evaluate the current studies on JE, only. Meta‐analysis, as a reviewing method, should be used in future research on clarifying the relationships between JE and other constructs in organizational behavior.
Originality/value
This research reviews almost all of the studies on JE from 2001 to 2009 and organizes and categorizes them into three kinds: cause, consequence and theoretical extension. The authors also summarize its relationships with other constructs (e.g. turnover, turnover intention, organizational commitment, organizational citizenship behavior) in various settings. Finally, based on discussion, the authors indicate future research directions.
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Xiangdi Yue, Jiawei Chen, Yihuan Zhang, Siming Huang, Jiaji Pan and Miaolei He
Over the decades, simultaneous localization and mapping (SLAM) techniques have been extensively researched and applied in robotic mapping. In complex environments, SLAM systems…
Abstract
Purpose
Over the decades, simultaneous localization and mapping (SLAM) techniques have been extensively researched and applied in robotic mapping. In complex environments, SLAM systems using a single sensor, such as a camera or light detection and ranging (LiDAR), often cannot meet the accuracy and map consistency requirements. This study aims to propose a tightly-coupled LiDAR-inertial SLAM system, which aims to achieve higher accuracy and map consistency for robotic mapping in complex environments.
Design/methodology/approach
This paper presents TC-Mapper, a tightly coupled LiDAR-inertial SLAM system based on LIO-SAM. The authors introduce the normal distribution-based loop closure detection method to the original one (i.e. the radius search-based method), which can enhance the accuracy and map consistency for robotic mapping. To further suppress map drift in complex environments, this paper incorporates a gravity factor into the original factor graph. In addition, TC-Mapper introduces incremental voxels (iVox) as the point cloud spatial data structure.
Findings
Extensive experiments in public and self-collected data sets demonstrate that TC-Mapper has high accuracy and map consistency.
Originality/value
TC-Mapper has two types of loop closure detections: the normal distribution-based method for correcting large drifts and the radius search-based method for fine-stitching, which can achieve higher accuracy and map consistency. The authors introduce iVox as the point cloud spatial data structure, which strives to attain a balance between precision and efficiency to the greatest extent feasible.
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Wuttiporn Suamuang, Surachai Suksakulchai and Elizabeth Murphy
The purpose of this paper is to simultaneously investigate a variety of factors related to assignment completion (AC) (i.e. task orientation, cooperation, teacher feedback, time…
Abstract
Purpose
The purpose of this paper is to simultaneously investigate a variety of factors related to assignment completion (AC) (i.e. task orientation, cooperation, teacher feedback, time management and time spent on AC).
Design/methodology/approach
The study relied on a self-report survey to assess students' perceptions in relation to six variables. Participants included 1,106 undergraduate students from six public Thai universities. Analysis involved structural equation modeling.
Findings
This study provided new results related to task orientation as the strongest predictor of AC and time management. Cooperation and feedback improved AC with time management as an intervening variable. Time management and feedback did not predict time spent on AC.
Research limitations/implications
Future studies might explore the potential range of assignments that, for example, count for a higher portion of the grade versus those that are less or unimportant in terms of the course. Future studies might also look at the role of group assignments in relation to completion. Semi-structured interviews or observations might provide insights into how students manage their time and why task orientation has the most effect on AC. Future research might investigate more specifically at what point time management does or does not affect completion. In general, given the growth of online learning and contexts in which students may be increasingly called on to complete assignments independently, factors such as those investigated in this study will require more attention in varying countries and contexts, generically and for individual subjects.
Practical implications
Instructional designers and instructors can promote task orientation through reliance on strategic scaffolding. For designing a task-oriented environment, instructors need to offer challenging assignments. Instructors should also assign work that encourages motivation, effort and achievement. To ensure that cooperative learning positively affects time management, instructors and designers can allot specific in-class time for completion of tasks, reliance on flipped classroom activities and student conversations regarding time restrictions and time-management skills. Instructors can be supported to help them provide appropriate types of feedback, as well as ideas for implementing the feedback in practice.
Originality/value
Little research has been conducted on AC in higher education. Those studies that have been conducted have focused on the elementary and secondary levels. Furthermore, studies have not always taken into account the complex relationships between different factors that can potentially influence AC.
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Robert M. Pech, Richard J. Pech, Ding Wei and Hong Shi
Through a case study of the Jiangsu Little Swan Group Company in the People's Republic of China aims to describe the transition from initial attempts at imitation of products…
Abstract
Purpose
Through a case study of the Jiangsu Little Swan Group Company in the People's Republic of China aims to describe the transition from initial attempts at imitation of products through to the realisation that innovation would need to be purchased
Design/methodology/approach
Relates the ensuing strategic alliance between the Jiangsu Little Swan Group Company and Matsushita of Japan, the acquisition of critical technology, and finally, the development of the company' own R&D culminating in over 150 technology patents by the end of the year 2002.
Findings
Finds that Little Swan has demonstrated that it is possible to successfully make an extraordinary revolutionary shift from one industry into another.
Originality/value
The case of Little Swan clearly demonstrates that innovation can be successfully integrated into a firm from external sources through direct acquisition.
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Bingzi Jin, Xiaojie Xu and Yun Zhang
Predicting commodity futures trading volumes represents an important matter to policymakers and a wide spectrum of market participants. The purpose of this study is to concentrate…
Abstract
Purpose
Predicting commodity futures trading volumes represents an important matter to policymakers and a wide spectrum of market participants. The purpose of this study is to concentrate on the energy sector and explore the trading volume prediction issue for the thermal coal futures traded in Zhengzhou Commodity Exchange in China with daily data spanning January 2016–December 2020.
Design/methodology/approach
The nonlinear autoregressive neural network is adopted for this purpose and prediction performance is examined based upon a variety of settings over algorithms for model estimations, numbers of hidden neurons and delays and ratios for splitting the trading volume series into training, validation and testing phases.
Findings
A relatively simple model setting is arrived at that leads to predictions of good accuracy and stabilities and maintains small prediction errors up to the 99.273th quantile of the observed trading volume.
Originality/value
The results could, on one hand, serve as standalone technical trading volume predictions. They could, on the other hand, be combined with different (fundamental) prediction results for forming perspectives of trading trends and carrying out policy analysis.
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Zengqiang Jiang, Dragan Banjevic, Mingcheng E., Andrew Jardine and Qi Li
The purpose of this paper is to develop an approach for estimating the remaining useful life (RUL) of metropolitan train wheels considering measurement error.
Abstract
Purpose
The purpose of this paper is to develop an approach for estimating the remaining useful life (RUL) of metropolitan train wheels considering measurement error.
Design/methodology/approach
The paper proposes a wear model of a metropolitan train wheel based on a discrete state space model; the model considers the wheel’s stochastic degradation and measurement error simultaneously. The paper estimates the RUL on the basis of the estimated degradation state. Finally, it presents a case study to verify the proposed approach. The results indicate that the proposed method is superior to methods that do not consider measurement error and can improve the accuracy of the estimated RUL.
Findings
RUL estimation is a key issue in condition-based maintenance and prognostics and health management. With the rapid development of advanced sensor technologies and data acquisition facilities for the maintenance of metropolitan train wheels, condition monitoring (CM) is becoming more accurate and more affordable, creating the possibility of estimating the RUL of wheels using CM data. However, the measurements of the wheels, especially the wayside measurements, are not yet precise enough. On the other hand, few existing studies of the RUL estimation of train wheels consider measurement error.
Practical implications
The approach described in this paper will make the RUL estimation of metropolitan train wheels easier and more precise.
Originality/value
Hundreds of million yuan are wasted every year due to over re-profiling of rail wheels in China. The ability to precisely estimate RUL will reduce the number of re-profiling activities and achieve significant economic benefits. More generally, the paper could enrich the body of knowledge of RUL estimation for a slowly degrading system considering measurement error.
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Bingsheng Xu, Yan Wu, Lina Zhang, Junwei Chen and Zhangfu Yuan
This research aims to provide a theoretical method and data supports for a future study on interfacial reaction mechanism and spreading mechanism between molten solder and…
Abstract
Purpose
This research aims to provide a theoretical method and data supports for a future study on interfacial reaction mechanism and spreading mechanism between molten solder and V-shaped substrate, which also gives guidance for those complicated welding operation objects in brazing technique.
Design/methodology/approach
Wetting experiments were performed to measure the contact angles at different temperatures of molten Sn-3.0Ag-0.5Cu wetting on the quartz substrate with an included angle of 90°. According to the experimental results, the theoretical spreading morphology of molten solder on V-shaped substrate at corresponding temperature was simulated by Surface Evolver.
Findings
The theoretical morphology profiles of the molten solder sitting on the V-shaped substrate are simulated using Surface Evolver when the molten solder reaches spreading equilibrium. The spreading mechanisms as well as the impact of surface tension and gravity on interfacial energy of the molten solder wetting on the V-shaped groove substrate are also discussed where theoretical results agree well with experiment results. The contact area between the gas and liquid phases shows a tendency of first increasing and later decreasing. Otherwise, the spreading distance and the height of the molten solder increases as the droplet volume increases as the included angle and the contact angle are given as constants, and both the interfacial energy and the gravitational energy increase as well. This research has a wide influence on predicting the outcomes in commercial impact and also gives guidance for those complicated welding operation objects in brazing technique.
Research limitations/implications
It is of very important significance in both science and practice to investigate the differences between the flat surface and V-shaped surface. Some necessary parameters including intrinsic contact angle and surface tension need to be directly measured when the droplet spreads on the flat surface. The relevant simulation conclusions on the inherent characteristics can be given based on these intrinsic parameters. Compared with the flat surface, the V-shaped substrate is chosen for further discuss on the effects of gravity on the droplet spreading behavior and the changes of apparent contact angle which can only occurs as the substrate is inclined. Therefore, this research provides theoretical method and data supports for a future study on interfacial reaction mechanism and spreading mechanism between molten solder and substrate.
Practical implications
The research is developed for verifying the accuracy of the model built in Surface Evolver. Based on this verified model, other researches on the spreading distance along y-axis and the contact area that are especially difficult to be experimentally measured can be directly simulated by Surface Evolver, which can provides a convenient method to discuss the changes of horizontal spreading distance, droplet height and contact area with increasing the included angle of V-shaped substrate or with increasing the droplet volume. Actually, the modeling results are calculated for supplying the theoretical parameters and technical guidance in the welding process.
Social implications
This research provides theoretical method and data supports for a future study on interfacial reaction mechanism and spreading mechanism between molten solder and substrate, which has a wide influence on prediction the outcomes in commercial impact and also gives guidance for those complicated welding operation objects in brazing technique.
Originality/value
Surface Evolver, can also be used to discuss the structure and spreading mechanism of droplets on V-shaped substrates, which have not been discussed before.
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This chapter examines China’s corporate governance and accounting environment that shapes the adoption of internationally acceptable principles and standards. Specifically, it…
Abstract
This chapter examines China’s corporate governance and accounting environment that shapes the adoption of internationally acceptable principles and standards. Specifically, it examines international influences, including supranational organizations; foreign investors and international accounting firms; domestic institutional influences, including the political system, economic system, legal system, and cultural system; and accounting infrastructure. China’s convergence is driven by desired efficiency of the corporate sector and legitimacy of participating in the global market. Influenced heavily by international forces in the context of globalization, corporate governance and accounting practices are increasingly becoming in line with internationally acceptable standards and codes. While convergence assists China in obtaining legitimacy, improving efficiency is likely to be adversely affected given that corporate governance and accounting in China operate in an environment that differs considerably from those of Anglo-American countries. An examination of the corporate governance and accounting environment in China suggests heavy government involvement within underdeveloped institutions. While the Chinese government has made impressive progress in developing the corporate governance and accounting environment for the market economy, China’s unique institutional setting is likely to affect how the imported concepts are interpreted and implemented.