Yazhou Mao, Daqing Li, Lilin Li and Jingyang Zheng
This study aims to improve the tribological properties of hydrodynamic journal bearing via surface texture, as well as the wear and antifriction mechanisms of textured bearing…
Abstract
Purpose
This study aims to improve the tribological properties of hydrodynamic journal bearing via surface texture, as well as the wear and antifriction mechanisms of textured bearing were represented. It provides a design direction for solving the tribological problem of rotor-bearing system.
Design/methodology/approach
In this paper, the variation of surface texture parameters (e.g. texture diameter, d; area density, sp; and depth, hp) were analyzed based on finite difference method. The optimal surface texture parameters were obtained by designing orthogonal experiments, and the relationship between friction and wear properties and microstructure was studied via combining electron probe microanalyzer, scanning electron microscope, X-ray diffractometer and friction and wear testing machine.
Findings
Dimensionless film pressure P increased as the d increased, whereas P first increased and then decreased as the sp and hp increased, and the maximum P was got as sp = 15% and hp = 25 µm, respectively. The friction coefficient of textured surface with suitable parameters was effectively reduced and the textured surface with the best antifriction effect was 5#. Orthogonal experimental design analysis showed that the influence order of factors on friction coefficient was as follows: sp > sp × d > d > d × hp > hp > sp × hp and the friction coefficient first decreased and then increased as the sp, d and hp increased. In addition, the friction and wear mechanism of textured bearing were three body friction and abrasive wear as the matrix structure and hard phase were a single β phase and Mn5Si3, respectively. While the antifriction mechanism of textured surface was able to store abrasive particles and secondary hydrodynamic lubrication was formed.
Originality/value
The sample with reasonable texture parameter design can effectively reduce friction and wear of hydrodynamic journal bearing without reducing the service life, which can provide a reference for improving the lubrication performance and mechanical efficiency of rotor-bearing system.
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This paper aims to present a novel energy-efficient saturated open-core fault current limiter (FCL) with special permanent magnet (PM) modules.
Abstract
Purpose
This paper aims to present a novel energy-efficient saturated open-core fault current limiter (FCL) with special permanent magnet (PM) modules.
Design/methodology/approach
The special PM modules are used to drive the cores of FCL into a saturated state from different directions in the normal operation condition, reducing the DC current of the saturated open-core FCL. An equivalent magnetic circuit model of the saturated open-core FCL with PM modules is built to calculate the magnetic flux density in the cores of FCL. By applying the modified nodal approach on the circuit, the nonlinear equations of the magnetic circuit can be achieved. The Newton – Raphson method is used to solve the nonlinear equations. The model shows good accuracy verified by finite element simulation and a physical experiment.
Findings
Compared with the original saturated open-core FCL structure with PMs, the novel saturated open-core FCL structure can save 84% DC power. The physical experiment results show that the saturated open-core FCL has a good performance on limiting the fault current.
Originality/value
A novel saturated open-core FCL structure with PM modules is proposed in this paper. A physical model of the saturated open-core FCL structure with PM modules is manufactured and tested. About 84% DC power can be reduced by using the PM modules in this saturated open-core FCL, and it can save most of the cost of the saturated open-core FCL.
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Yuqing Xie, Lin Li and Shuaibing Wang
To reduce the computational scale for quasi-magnetostatic problems, model order reduction is a good option. Reduced-order modelling techniques based on proper orthogonal…
Abstract
Purpose
To reduce the computational scale for quasi-magnetostatic problems, model order reduction is a good option. Reduced-order modelling techniques based on proper orthogonal decomposition (POD) and centroidal Voronoi tessellation (CVT) have been used to solve many engineering problems. The purpose of this paper is to investigate the computational principle, accuracy and efficiency of the POD-based and the CVT-based reduced-order method when dealing with quasi-magnetostatic problems.
Design/methodology/approach
The paper investigates computational features of the reduced-order method based on POD and CVT methods for quasi-magnetostatic problems. Firstly the construction method for the POD and the CVT reduced-order basis is introduced. Then, a reduced model is constructed using high-fidelity finite element solutions and a Galerkin projection. Finally, the transient quasi-magnetostatic problem of the TEAM 21a model is studied with the proposed reduced-order method.
Findings
For the TEAM 21a model, the numerical results show that both POD-based and CVT-based reduced-order approaches can greatly reduce the computational time compared with the full-order finite element method. And the results obtained from both reduced-order models are in good agreement with the results obtained from the full-order model, while the computational accuracy of the POD-based reduced-order model is a little higher than the CVT-based reduced-order model.
Originality/value
The CVT method is introduced to construct the reduced-order model for a quasi-magnetostatic problem. The computational accuracy and efficiency of the presented approaches are compared.
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Yaqi Wang, Lin Li and Xiaojun Zhao
The purpose of this paper is to combine the Jiles-Atherton (J-A) hysteresis model with the field separation approach to realize the accurate simulation of dynamic magnetostrictive…
Abstract
Purpose
The purpose of this paper is to combine the Jiles-Atherton (J-A) hysteresis model with the field separation approach to realize the accurate simulation of dynamic magnetostrictive characteristics of silicon steel sheet.
Design/methodology/approach
First, the energy loss of silicon steel sheet is divided into hysteresis loss Why, classical eddy current loss Wed and anomalous loss Wan according to the statistical theory of losses. The Why is calculated by static J-A hysteresis model, Wed and Wan are calculated by the analytical formulae. Then, based on the field separation approach, the dynamic magnetic field is derived. Finally, a new dynamic magnetostrictive model is proposed by means of the quadratic domain rotation model.
Findings
Comparison of simulation and experimental results verifies that the proposed model has high accuracy and strong universality.
Originality/value
The proposed method improves the existing method’s problem of relying on too much experimental data, and the method ensures the calculation accuracy, parameter identification accuracy and engineering practicability. Consequently, the presented work greatly facilitates further explorations and studies on simulation of dynamic magnetostrictive characteristics of silicon steel sheet.
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Lin Li, Xi Yu Leung and Liyu Yang
The surge of social media as a pivotal platform for individuals to access travel-related information has become increasingly significant. Drawing upon social-technical theory and…
Abstract
Purpose
The surge of social media as a pivotal platform for individuals to access travel-related information has become increasingly significant. Drawing upon social-technical theory and weak tie theory, this study aims to delve into the antecedents and moderating variables shaping impulsive travel intentions within social media.
Design/methodology/approach
Data were collected from 696 Chinese social media users and travelers and analyzed using partial least squares structural equation modeling (PLS-SEM).
Findings
The findings indicate that information quality and social network interaction significantly influence spatial presence, thereby increasing users’ impulsive travel intentions. The moderating roles of tie strength and face consciousness are confirmed. For travelers with strong ties, their spatial presence is impacted more by social network interaction. Conversely, for individuals with weak ties, spatial presence is more influenced by information quality. In addition, travelers with heightened face consciousness exhibit a diminished susceptibility to the influence of spatial presence on their travel intentions compared to those with lower face consciousness.
Originality/value
The study endeavors to extend the application of the social-technical theory in the domain of tourism social media marketing by examining the interplay of technological and social attributes on impulsive travel intention. It integrates weak tie theory into the socio-technical perspective, emphasizing the importance of weak ties in the social media environment and their influence on travel behavior. In addition, this study introduces face consciousness to the mechanism, seeking to broaden the research scope and capture the nuances of specific cultural contexts. The insights contribute valuable knowledge for destinations and tourism companies to optimize social media marketing.
研究目的
社交媒体作为个人获取旅行相关信息的重要平台, 其影响力日益显著。本研究基于社会技术理论和弱关系理论, 探讨社交媒体中塑造冲动旅行意图的前因和调节变量。
研究方法
本研究收集了696名中国社交媒体用户和旅行者的数据, 并采用偏最小二乘法结构方程建模(PLS-SEM)进行分析。
研究发现
研究结果表明, 信息质量和社交网络互动显著影响空间存在感, 从而增强用户的冲动旅行意图。研究确认了关系强度和面子意识的调节作用。对于有强关系的旅行者来说, 社交网络互动对他们的空间存在感影响更大。相反, 对于有弱关系的个体, 信息质量对空间存在感的影响更为显著。此外, 面子意识较强的旅行者在空间存在感对其旅行意图的影响上表现出更低的敏感性, 相较于面子意识较低的个体。
研究创新
本研究旨在扩展社会技术理论在旅游社交媒体营销领域的应用, 通过考察技术属性与社会属性对冲动旅行意图的相互作用。研究将弱关系理论融入社会技术视角, 强调了社交媒体环境中弱关系的重要性及其对旅行行为的影响。此外, 本研究引入了面子意识的机制, 旨在拓宽研究范围, 捕捉特定文化背景下的细微差异。研究结果为旅游目的地和公司优化社交媒体营销提供了宝贵的知识。
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Qiao Liang, Lin Li and Rongrong Bai
The purpose of this paper is to estimate the effect of vegetable producers' inclusiveness in supply chain coordination on vegetable production performance and potential spillover…
Abstract
Purpose
The purpose of this paper is to estimate the effect of vegetable producers' inclusiveness in supply chain coordination on vegetable production performance and potential spillover effect on farm and non-farm income.
Design/methodology/approach
A comprehensive dataset comprised of 410 paired vegetable producers in China is applied. Propensity score matching (PSM) estimation method is used to control for the selection bias problem.
Findings
The empirical results indicate that contracting farming does not have significant effect on yield or profit of vegetable production, but promote producers to obtain quality certification. In comparison, cooperative membership has positive effects on the yield, profit and quality certification of producers. Additionally, cooperatives generate positive spillover effects on members' farm and non-farm income, though the results are sensitive to unobserved factors. The inclusion of spillover effects helps to find out the potential unobserved effects which are neglected by most studies and design better policies to promote the development of agricultural companies and farmer cooperatives.
Originality/value
First, empirical evidence is provided for theories regarding the roles of different supply chain coordination modes on producers. Second, the analysis on evaluating the effects of supply chain coordination also considers the spillover effect on the farming of other products and even non-farm work of involved producers. Third, a unique dataset comprised of 420 paired vegetable producers, based on an extensive survey is built.
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Jingyu Cheng, Minxi Wang, Lilin Wu and Xin Li
The purpose of this paper is to explore the high-quality development (HQD) strategy of Chinese mineral resource enterprises, which is important for Chinese mineral resource…
Abstract
Purpose
The purpose of this paper is to explore the high-quality development (HQD) strategy of Chinese mineral resource enterprises, which is important for Chinese mineral resource enterprises to improve the efficiency and benefit of resource utilization, reduce the intensity of resource and energy consumption and gradually form resource-saving and environment-friendly enterprises.
Design/methodology/approach
This study establishes an evaluation index system with four dimensions: economy, environment, society and management innovation. The entropy value method assigns weights to them and then uses the system dynamics (SD) model for case simulation.
Findings
The results of the SD simulation conclude that the fulfillment of social responsibility and the implementation of management innovation can accelerate the realization of HQD of mineral resource enterprises; profitability plays a crucial role in economic indicators; the improvement of energy-saving volume has the most significant impact on environmental benefits; the social contribution is the key element to measure social indicators; and the sales rate of core products has the most significant impact on the benefits of management innovation.
Originality/value
Based on the few studies on the evaluation of the development strategy of mineral resource enterprises, this study establishes an evaluation index system that considers the interactions between indicators, combines the entropy value method with SD and uses the SD model to comprehensively and systematically analyze the impact and degree of each factor on the HQD of mineral resource enterprises.
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Manish Bansal and Hajam Abid Bashir
This study aims to investigate the impact of business strategy on the classification shifting practices of Indian firms.
Abstract
Purpose
This study aims to investigate the impact of business strategy on the classification shifting practices of Indian firms.
Design/methodology/approach
The study considered cost leadership and differentiation strategy. Two forms of classification shifting, namely, expense misclassification and revenue misclassification have been examined in this study. Panel data regression models are used to analyze the data for this study.
Findings
The results show that managers of cost leadership strategy firms are more likely to be engaged in expense misclassification, whereas firms following differentiation strategy are likely to be engaged in revenue misclassification. Subsequent tests of this study suggest that firms following a hybrid strategy (mix of cost leadership and differentiation) prefer revenue misclassification over expense misclassification for reporting inflated operating performance. These results imply that firms prefer the shifting tool based on the ease and need of each shifting strategy. These results are consistent with several robustness measures.
Practical implications
The results suggest that investors should understand business strategy before developing insights about the accounting quality of firms. Investors should conduct a comprehensive review of income statement items before using items for portfolio evaluation.
Originality/value
To the best of the authors’ knowledge, this is the first study to examine the association between business strategy and classification shifting.
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Jian Tang, Xiang Cui, Lei Qi, Tiebing Lu, Lin Li, Puxuan Zhu, Guang Yang and Weizhen Zhang
The purpose of this paper is to present a method to calculate the transient induced voltages along the underground pipelines and analyze the transient interference generated in…
Abstract
Purpose
The purpose of this paper is to present a method to calculate the transient induced voltages along the underground pipelines and analyze the transient interference generated in the pipelines due to the inductive coupling in the fault‐to‐ground condition of power lines in close proximity.
Design/methodology/approach
Based on finite difference‐time domain method, an improved method is proposed to calculate transient inductive interference in underground metallic pipelines due to a fault in nearby power lines. The frequency‐dependent problem in the analysis of transient interference is solved in phase domain. Compared with the traditional method, the disposal of phase‐modal transformation matrices’ frequency‐dependent characteristic is avoided and the calculation is simplified by using vector fitting approach and recursive algorithm greatly in the proposed method.
Findings
A novel improved method is proposed to calculate transient induced voltage distribution along underground metallic pipelines due to a fault in nearby power lines. Results show that the peak value of transient induced voltage at the most critical point is about 1.15 times of the magnitude in the steady state without the fault removed and the analysis of transient inductive interference is necessary in the fault‐to‐ground case of power lines.
Practical implications
In order to mitigate the interference from power lines to nearby pipelines, pipelines should be good grounded and positioned as far away from the power line as possible. In high soil resistivity areas, the common corridor should be avoided.
Originality/value
The paper presents a method to calculate the transient induced voltages along the underground pipelines and analyze the transient interference generated in the pipelines due to the inductive coupling in the fault‐to‐ground condition of nearby power lines. The proposed method is general and can also be applied to other transient interference studies such as crosstalk problems of communication networks and interference between power lines and aboveground pipelines or communication cables. Effects of various parameters upon the inductive interference generated in underground pipelines due to a fault in nearby power lines are analyzed to be a guide for controlling the inductive interference.
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Chen Kuilin, Feng Xi, Fu Yingchun, Liu Liang, Feng Wennan, Jiang Minggang, Hu Yi and Tang Xiaoke
The data protection is always a vital problem in the network era. High-speed cryptographic chip is an important part to ensure data security in information interaction. This paper…
Abstract
Purpose
The data protection is always a vital problem in the network era. High-speed cryptographic chip is an important part to ensure data security in information interaction. This paper aims to provide a new peripheral component interconnect express (PCIe) encryption card solution with high performance, high integration and low cost.
Design/methodology/approach
This work proposes a System on Chip architecture scheme of high-speed cryptographic chip for PCIe encryption card. It integrated CPU, direct memory access, the national and international cipher algorithm (data encryption standard/3 data encryption standard, Rivest–Shamir–Adleman, HASH, SM1, SM2, SM3, SM4, SM7), PCIe and other communication interfaces with advanced extensible interface-advanced high-performance bus three-level bus architecture.
Findings
This paper presents a high-speed cryptographic chip that integrates several high-speed parallel processing algorithm units. The test results of post-silicon sample shows that the high-speed cryptographic chip can achieve Gbps-level speed. That means only one single chip can fully meet the requirements of cryptographic operation performance for most cryptographic applications.
Practical implications
The typical application in this work is PCIe encryption card. Besides server’s applications, it can also be applied in terminal products such as high-definition video encryption, security gateway, secure routing, cloud terminal devices and industrial real-time monitoring system, which require high performance on data encryption.
Social implications
It can be well applied on many other fields such as power, banking, insurance, transportation and e-commerce.
Originality/value
Compared with the current strategy of high-speed encryption card, which mostly uses hardware field-programmable gate arrays or several low-speed algorithm chips through parallel processing in one printed circuit board, this work has provided a new PCIe encryption card solution with high performance, high integration and low cost only in one chip.