Zhishuang Wang, Songhua Li, Jian Sun, Junhai Wang, Yonghua Wang, Zhongxian Xia and Chao Wei
The purpose of this study is to investigate the effects of load and rotation speed on dry sliding of silicon nitride, including a series of tribological behaviors (friction…
Abstract
Purpose
The purpose of this study is to investigate the effects of load and rotation speed on dry sliding of silicon nitride, including a series of tribological behaviors (friction coefficient, wear rate, temperature rise, etc.) and wear mechanism. Through the analysis of the above characteristics, the influence law of load and speed on them and the internal relationship between them are determined, and then the best comprehensive performance parameters of silicon nitride full-ceramic spherical plain bearings in dry sliding are predicted, which can provide guidance for the operation condition of silicon nitride full-ceramic spherical plain bearings in dry sliding.
Design/methodology/approach
The experimental study of different loads and rotation speeds under dry friction conditions was carried out by the using ball-disk sliding test method.
Findings
With the increase of load, the friction coefficient of silicon nitride friction pair and the wear rate of silicon nitride ball decrease continuously. With the increase of rotation speed, the friction coefficient of silicon nitride friction pair first increases and then decreases, and the wear of silicon nitride ball first increases and then decreases. With the increase of load and rotation speed, the wear mechanism eventually changes to adhesive wear.
Originality/value
Because of the low timeliness and inefficiency of bearing experiments, this work adopts a simple ball-disk model to comprehensively explore the influence rules of different conditions, which provides a theoretical basis for the subsequent practical application of silicon nitride full-ceramic spherical plain bearings.
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Ting Li, Zhipeng Zhang, Junhai Wang, Tingting Yan, Rui Wang, Xinran Li, Lixiu Zhang and Xiaoyi Wei
This study aims to prepare thymol-based deep eutectic solvents (DESs) and use them as lubricates for friction and wear tests to simulate the wear conditions of hybrid bearings.
Abstract
Purpose
This study aims to prepare thymol-based deep eutectic solvents (DESs) and use them as lubricates for friction and wear tests to simulate the wear conditions of hybrid bearings.
Design/methodology/approach
Through the characterization and analysis of the morphology of wear scars and the elemental composition of friction films, the tribological behavior and wear mechanism of sample materials as lubricants were investigated and the anti-wear mechanism of thymol-based DESs was discussed.
Findings
The findings demonstrate that because of the formation of a fluid lubrication film and excellent kinematic viscosity, the lubrication effect of the prepared DES is improved by about 50% compared to the base lubricating oil. The prepared [Ch]Cl-thymol DES has a better anti-friction and lubrication effect than citric-thymol, EG-thymol and urea-thymol DESs, with an average friction coefficient of about 0.04.
Originality/value
In this work, the friction reduction properties of thymol-based DESs were studied as lubricants for the first time, and the lubrication mechanism of sample materials was investigated.
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Ting Li, Junmiao Wu, Junhai Wang, Yunwu Yu, Xinran Li, Xiaoyi Wei and Lixiu Zhang
The purpose of this article is to prepare graphene/polyimide composite materials for use as bearing cage materials, improving the friction and wear performance of bearing cages.
Abstract
Purpose
The purpose of this article is to prepare graphene/polyimide composite materials for use as bearing cage materials, improving the friction and wear performance of bearing cages.
Design/methodology/approach
The oil absorption and discharge tests were conducted to evaluate the oil content properties of the materials, while the mechanical properties were analyzed through cross-sectional morphology examination. Investigation into the tribological behavior and wear mechanisms encompassed characterization and analysis of wear trace morphology in PPI-based materials. Consequently, the influence of varied graphene nanoplatelets (GN) concentrations on the oil content, mechanical and tribological properties of PPI-based materials was elucidated.
Findings
The composites exhibit excellent oil-containing properties due to the increased porosity of PPI-GN composites. The robust formation of covalent bonds between GN and PPI amplifies the adhesive potency of the PPI-GN composites, thereby inducing a substantial enhancement in impact strength. Notably, the PPI-GN composites showed enhanced lubrication properties compared to PPI, which was particularly evident at a GN content of 0.5 Wt.%, as evidenced by the minimization of the average coefficient of friction and the width of the abrasion marks.
Practical implications
This paper includes implications for elucidating the wear mechanism of the polyimide composites under frictional wear conditions and then to guide the optimization of oil content and tribological properties of polyimide bearing cage materials.
Originality/value
In this paper, homogeneously dispersed PPI-GN composites were effectively synthesized by introducing GN into a polyimide matrix through in situ polymerization, and the lubrication mechanism of the PPI composites was compared with that of the PPI-GN composites to illustrate the composites’ superiority.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-12-2023-0415
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Ting Li, Xianggang Chen, Junhai Wang, Lixiu Zhang, Xinran Li and Xiaoyi Wei
The purpose of this study is to prepare ZnFe2O4 nanospheres, sheet MoS2 and three ZnFe2O4@MoS2 core-shell composites with various shell thicknesses, and add them to the base oil…
Abstract
Purpose
The purpose of this study is to prepare ZnFe2O4 nanospheres, sheet MoS2 and three ZnFe2O4@MoS2 core-shell composites with various shell thicknesses, and add them to the base oil for friction and wear tests to simulate the wear conditions of hybrid bearings.
Design/methodology/approach
Through the characterization and analysis of the morphology of wear scars and the elemental composition of friction films, the tribological behavior and wear mechanism of sample materials as lubricant additives were investigated and the effects of shell thickness and sample concentration on the tribological properties of core–shell composite lubricant additives were discussed.
Findings
The findings demonstrate that each of the five sample materials can, to varying degrees, enhance the lubricating qualities of the base oil and that the core–shell nanocomposite sample lubricant additive has superior lubricating properties to those of ZnFe2O4 and MoS2 alone, among them ZnFe2O4@MoS2-2 core–shell composites with moderate shell thickness performed most ideally. In addition, the optimal concentration of the ZnFe2O4@MoS2 lubricant additive was 0.5 Wt.%, and a concentration that was too high led to particle deposition and affected the friction effect.
Originality/value
In this work, ZnFe2O4@MoS2 core–shell composites were synthesized for the first time using ZnFe2O4 as the carrier and the lubrication mechanism of core–shell composites and single materials were compared and studied, which illustrated the advantages of core–shell composite lubricant additives. At the same time, the influence of different shell thicknesses on the lubricant additives of core–shell composites was studied.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-12-2022-0367/
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Jian Sun, Guangxiang Zhang, Zhongxian Xia, Zhigang Bao, Jinmei Yao, Xin Fang, Zhe Zhang and Renyun Guan
To understand the service performance of full ceramic ball bearings under extreme working conditions and improve their service life, dynamic characteristic tests of full ceramic…
Abstract
Purpose
To understand the service performance of full ceramic ball bearings under extreme working conditions and improve their service life, dynamic characteristic tests of full ceramic ball bearings under ultra-low temperature conditions were carried out by a low-temperature bearing life testing machine, and temperature rise and friction were measured under extreme low-temperature environment.
Design/methodology/approach
The heat-flow coupling model of bearing was established by CFD software, and the test results were further analyzed.
Findings
The results show that the temperature rise of the bearing is not obvious in the liquid nitrogen environment. With the increase of the chamber temperature, the lubrication state of the bearing changes, resulting in the temperature rise of the outer ring of the bearing. As the temperature of the test chamber increases, the friction force on the bearing increases first and then decreases under the action of multifactor coupling.
Research limitations/implications
The research results provide test data and theoretical basis for the application of all-ceramic ball bearings in aerospace and other fields and have important significance for improving the service life of high-end equipment under extreme working conditions.
Practical implications
The research results provide test data and theoretical basis for the application of full ceramic ball bearings in aerospace and other fields and have important significance for improving the service life of high-end equipment under extreme working conditions.
Social implications
The research results provide test data and theoretical basis for the application of full ceramic ball bearings in aerospace and other fields and have important significance for improving the service life of high-end equipment under extreme working conditions.
Originality/value
The research results provide test data and theoretical basis for the application of full ceramic ball bearings in aerospace and other fields and have important significance for improving the service life of high-end equipment under extreme working conditions.
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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.
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Yaming Wang, Jie Han, Junhai Li and Chunlan Mou
This research is aimed to examine how environmental pollution affects consumers' preference for self-improvement products.
Abstract
Purpose
This research is aimed to examine how environmental pollution affects consumers' preference for self-improvement products.
Design/methodology/approach
Through a series of three experimental studies, this research substantiates our hypotheses by employing various manipulations of environmental pollution and examining different types of self-improvement products.
Findings
The research demonstrates that environmental pollution enhances consumers' preference for self-improvement products via the mediation of perceived environmental responsibility. And the effect is negatively moderated by social equity sensitivity.
Originality/value
The recurrent incidence of environmental pollution has elicited significant concern among the general public and academic scholars. An overwhelming majority of research examining the impact of pollution on consumer behavior has concentrated on its influence on environmentally friendly and healthy consumption patterns. Nevertheless, the current research proposes that pollution fosters a preference for products associated with self-improvement, mediated by perceived environmental responsibility, with the effects being moderated by social equity sensitivity.
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Junhai Ma and Yalan Hong
The convenience of online shopping enables the manufacturer to develop direct channels. To counter manufacturer encroachment, the retailer tends to provide presale service to…
Abstract
Purpose
The convenience of online shopping enables the manufacturer to develop direct channels. To counter manufacturer encroachment, the retailer tends to provide presale service to attract more customers. Meanwhile, the service provided by the retailer also has a positive impact on the manufacturer's sale volume, which is usually called the showrooming effect or free-ride. The purpose of this paper is to explore the dynamic game of pricing and service strategy in a dual-channel supply chain with risk attitudes and free-ride.
Design/methodology/approach
This paper considers the risk attitude, characterized by mean-variance theory. First, the optimal pricing and service strategy of two static models under two scenarios are derived. Second, dynamic games are then considered to explore the evolution of the decisions. The classical optimization method is used to solve the problem, and numerical experiments are done to analyze the complex characteristic of the system.
Findings
The result shows that the retailer is willing to provide a higher level of service if his risk preference is higher. The offline retail price and online retail price are positively related to the retailer's risk preference. Besides, the free-ride behavior can reduce the offline retail price and the level of service provided by the retailer. Furthermore, the study indicates that the system is more likely to enter chaos if the retailer's risk preference is higher. Additionally, consumers' service sensitivity and cost coefficient affect the stability of the system.
Originality/value
The study provides a different perspective on supply chain management considering risk attitudes and free-ride The findings of the study can offer theoretical and practical guidance for enterprises to choose adjustment measures according to their risk preference.
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Junhai Ma, Jie Fan, Meihong Zhu and Jiecai Chen
Food quality and safety issues have always been imperative topics discussed by people. The anti-tampering of blockchain technology and the transparency of information make it…
Abstract
Purpose
Food quality and safety issues have always been imperative topics discussed by people. The anti-tampering of blockchain technology and the transparency of information make it possible to improve food traceability and safety quality. How to effectively apply blockchain traceability technology to food safety has great research significance for improving food safety and consumer quality trust.
Design/methodology/approach
The paper aims to analyze the differences in product quality levels and market participants’ profits before and after the use of blockchain-driven traceability technology in the food agricultural product supply chain (SC) in the dynamic game frameworks of supplier-led and retailer-led modes, respectively, and explores the willingness, social welfare and consumer surplus of each member of the agricultural product SC to participate in the blockchain. Besides, We investigate the SC performance improvement with the mechanism of central centralized decision-making and revenue-sharing contract, compared to the SC performance in dynamic games.
Findings
The results are obtained as follow: The adoption of blockchain traceability technology can help improve the quality of food agricultural products, consumer surplus and social welfare, but the application and popularization of technology is hindered by traceability technology installment costs. Compared with the supplier leadership model, retailer-led food quality level, customer surplus and social welfare are higher.
Research limitations/implications
How to effectively apply blockchain traceability technology to food safety has great research significance for improving food safety and consumer quality trust.
Practical implications
Food quality and safety issues have always been hot topics discussed by people. The anti-tampering of blockchain technology and the transparency of information make it possible to improve food traceability and safety quality.
Social implications
The research results enrich the theories related to food safety and quality, and provide a valuable reference for food enterprises involved in the decision-making exploration of blockchain technology.
Originality/value
Based on the characteristics of blockchain technology, the demand function is adjusted and the product loss risk of channel members is transferred through a Stackelberg game SC composed of agricultural products suppliers and retailers.
Highlights:
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We introduce two features of blockchain: quality trust and product information tracking.
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The willingness of each member of the supply chain to use blockchain for product traceability was explored.
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The overall traceability effect of the retailer-led blockchain is better than that of the manufacturer-led blockchain.
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The cost of blockchain technology is a barrier to its adoption.
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Blockchain brings higher consumer surplus and social welfare.
We introduce two features of blockchain: quality trust and product information tracking.
The willingness of each member of the supply chain to use blockchain for product traceability was explored.
The overall traceability effect of the retailer-led blockchain is better than that of the manufacturer-led blockchain.
The cost of blockchain technology is a barrier to its adoption.
Blockchain brings higher consumer surplus and social welfare.
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The paper aims to discuss the amended provisions relating to protection of minority shareholders (PMS) in the newly amended Chinese Company Law and evaluate whether it adequately…
Abstract
Purpose
The paper aims to discuss the amended provisions relating to protection of minority shareholders (PMS) in the newly amended Chinese Company Law and evaluate whether it adequately protects the interests of minority shareholders.
Design/methodology/approach
In total, 26 cases will be examined by discussing the characteristics of the relevant parties involved, specifically plaintiffs, defendants, their lawyers, judges and also the grounds of complaint. A comparison will be made between the cases decided by following the first Company Law (1994) and the cases decided in accordance with the newly amended Company Law (2006).
Findings
The findings indicate that the amended Company Law has removed certain drawbacks in PMS present in the first Company Law (1994) but the New Company Law can protect interests of minority shareholders only to a certain extent. Further amendments are still needed.
Originality/value
This is one of the first studies to actually examine the implementation of PMS‐related provisions in the newly amended Company Law.