Dongfang Sun, Jingchun Tang, Xiuping Zhang, Xudong Yuan, Yue Qian, Fangping Ye, Bin Ye and Bin Jiang
The leakage problem caused by machining error, assembly error, wearing and thermal deformation has been the main factor hindering the development of scroll compressor. This paper…
Abstract
Purpose
The leakage problem caused by machining error, assembly error, wearing and thermal deformation has been the main factor hindering the development of scroll compressor. This paper aims to investigate the lubrication characteristics of radial clearance and further optimize the radial clearance, which can reduce the leakage in the tangential direction of the working chamber.
Design/methodology/approach
This paper establishes a model of radial clearance oil film lubrication in scroll compressor. And, the method to solve the Reynolds and energy equations is presented, as well as the dimensionless and discretization by finite element difference method. To verify the established model, performance experiment of scroll compressor for electric vehicle air conditioning system is also carried out.
Findings
Based on the presented model, the temperature field and distribution of the oil film in the radial clearance are analyzed. And the influence of the structural parameter on the radial clearance is further discussed. The optimum radial clearance could be achieved at β = 40°–42°, where the orbiting scroll is in the state of rotary balance. And, the simulation results coincide well with the experimental results.
Originality/value
This work provides an effective model to evaluate the lubrication characteristics of radial clearance in scroll compressor, which can provide guidance for the design of scroll compressor.
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Xudong Zhu, Li Yuan and Siying Chen
This chapter uses macro policy analysis conducted at the Center for Teacher Education Research (CTER), Beijing Normal University to analyze the decision-making concerning teacher…
Abstract
This chapter uses macro policy analysis conducted at the Center for Teacher Education Research (CTER), Beijing Normal University to analyze the decision-making concerning teacher internship from the perspective of national policy. Internship, a teacher preparation policy initiative in China, is both needed to ease the teacher shortages in rural and poor areas of China and to create new models of teaching practice. Attention is then given to two aspects in policy implementation – student teachers’ learning and teachers’ multiple forms of instruction – from the perspective of teacher preparation. To conclude, the chapter offers some summary statements having to do with the policy debate and the implementation of the internship in China.
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Lily Orland-Barak and Cheryl J. Craig
Teacher education pedagogies face the complex challenge of attending to standards of professionalism while being sensitive to the local changing needs of professional learning…
Abstract
Teacher education pedagogies face the complex challenge of attending to standards of professionalism while being sensitive to the local changing needs of professional learning. Encounters between these two aspects of professional work are manifested, for example, through the relations between innovative, “against the grain” pedagogies and standardized criteria and accountability to policy issues and measurement. This chapter characterizes various “contact zones” across participants, contexts and contents, called for by the four categories of pedagogies (working with multimodalities, partnerships and community learning, teacher assessment, and vehicles for dissemination) that comprise this volume of International Teacher Education: Promising Pedagogies (Part C). The four categories of pedagogies join five earlier categories of pedagogies (teacher leadership, diversity, family, social justice, and technology), which are found in International Teacher Education: Promising Pedagogies (Part B). These go in with yet another five categories of pedagogies (teacher selection, reflection, narrative knowing, teacher identity and mediation and mentoring), which are found in International Teacher Education: Promising Pedagogies (Part A).
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Cheryl J. Craig and Lily Orland-Barak
This scholarly work analyzes the previous 17 chapters in the International Teacher Education: Promising Pedagogies (Part C) volume. The purpose of the analysis is to distill the…
Abstract
This scholarly work analyzes the previous 17 chapters in the International Teacher Education: Promising Pedagogies (Part C) volume. The purpose of the analysis is to distill the essence of what constitutes promising international teacher education pedagogies and how those pedagogies can best be shared. The chapters are reviewed according to the sections in which they appeared: pedagogies of working with multimodalities; pedagogies of partnerships and communities; pedagogies of teacher assessment; and vehicles for teacher education research, and dissemination. Key knowledge contributions from each chapter are emphasized. Similarities between the featured pedagogies are also highlighted. Finally, overarching themes are pinpointed.
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Lizhen Cui, Xudong Zhao, Lei Liu, Han Yu and Yuan Miao
Allocation of complex crowdsourcing tasks, which typically include heterogeneous attributes such as value, difficulty, skill required, effort required and deadline, is still a…
Abstract
Purpose
Allocation of complex crowdsourcing tasks, which typically include heterogeneous attributes such as value, difficulty, skill required, effort required and deadline, is still a challenging open problem. In recent years, agent-based crowdsourcing approaches focusing on recommendations or incentives have emerged to dynamically match workers with diverse characteristics to tasks to achieve high collective productivity. However, existing approaches are mostly designed based on expert knowledge grounded in well-established theoretical frameworks. They often fail to leverage on user-generated data to capture the complex interaction of crowdsourcing participants’ behaviours. This paper aims to address this challenge.
Design/methodology/approach
The paper proposes a policy network plus reputation network (PNRN) approach which combines supervised learning and reinforcement learning to imitate human task allocation strategies which beat artificial intelligence strategies in this large-scale empirical study. The proposed approach incorporates a policy network for the selection of task allocation strategies and a reputation network for calculating the trends of worker reputation fluctuations. Then, by iteratively applying the policy network and reputation network, a multi-round allocation strategy is proposed.
Findings
PNRN has been trained and evaluated using a large-scale real human task allocation strategy data set derived from the Agile Manager game with close to 500,000 decision records from 1,144 players in over 9,000 game sessions. Extensive experiments demonstrate the validity and efficiency of computational complex crowdsourcing task allocation strategy learned from human participants.
Originality/value
The paper can give a better task allocation strategy in the crowdsourcing systems.
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Yuan Chen, Hao Shang, Xiaolu Li, Yuntang Li, Bingqing Wang and Xudong Peng
The purpose of this paper is to investigate the influence rule and mechanism of three degrees of freedom film thickness disturbance on the transient performance of spiral groove…
Abstract
Purpose
The purpose of this paper is to investigate the influence rule and mechanism of three degrees of freedom film thickness disturbance on the transient performance of spiral groove, upstream pumping spiral groove dry gas seal (UP-SDGS) and double-row spiral groove dry gas seal (DR-SDGS).
Design/methodology/approach
The transient performance of spiral groove, UP-SDGS and DR-SDGS are obtained by solving the transient Reynolds equation under different axial and angular disturbance coefficients. The transient and steady performance of the above-mentioned DGSs are compared and analyzed.
Findings
The film thickness disturbance has a remarkable impact on the sealing performance of DGS with different structures and the calculation deviations of the leakage rate of the UP-DGS will increase significantly if the film thickness disturbance is ignored. The axial and angular disturbance jointly affect the film thickness distribution of DGS, but there is no significant interaction between them on the transient sealing performance.
Originality/value
The influence mechanism of axial disturbance and angular disturbance on the transient performance of typical SDGSs behavior has been explained by theory. Considering small and large disturbance, the interaction between axial disturbance and angular disturbance on the transient performance have been studied.
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Xiaolong Yuan, Yongyong Yang, Feng Wang, Qian Ding, Mianlin Deng, Wendian Shi and Xudong Zhao
Drawing upon social information processing theory, this study investigates the correlation between self-serving leadership and employee expediency. It also explores the mediating…
Abstract
Purpose
Drawing upon social information processing theory, this study investigates the correlation between self-serving leadership and employee expediency. It also explores the mediating effect of self-interest motivation and the moderating effect of trait mindfulness.
Design/methodology/approach
A total of 147 part-time MBA students were enlisted to participate in a scenario experiment (Study 1), and 291 valid employee questionnaires were collected through a multiple-time point survey (Study 2). SPSS 23.0, MPLUS 8.0 and PROCESS programs were used to analyze the data and test the hypotheses.
Findings
Study 1 illustrated a positive correlation between self-serving leadership and employee expediency. It also identified self-interest motivation as a mediating factor in the correlation between self-serving leadership and expediency. Study 2 replicated the results obtained in Study 1 and expanded upon them by demonstrating that trait mindfulness moderates the association between self-serving leadership and self-interest motivation. Additionally, trait mindfulness moderates the indirect effect of self-serving leadership on expediency.
Practical implications
This research argues that organizations should take steps to prevent self-serving leadership in order to reduce employee expediency. Furthermore, it is advisable to provide ethics training to employees who exhibit high trait mindfulness, as they show increased sensitivity to self-serving leadership and are more likely to engage in unethical behavior.
Originality/value
This study expands the existing research on the ethical outcomes of self-serving leadership and contributes to a deeper understanding of the negative aspects of trait mindfulness.
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Xudong Sang, Lijie Yang, Dongli Li, Wencai Xu, Yabo Fu and Jiazi Shi
Honey peaches are rich in a variety of vitamins and are well known in China as the queen of fruit. However, as highly climacteric fruit, peach is too easy to affect its economic…
Abstract
Purpose
Honey peaches are rich in a variety of vitamins and are well known in China as the queen of fruit. However, as highly climacteric fruit, peach is too easy to affect its economic value. In this paper, a new passive modified atmosphere packaging system was proposed to solve the lack of water vapour removal capacity – which is still the technical bottleneck of passive modified atmosphere packaging. This paper aims to address this issue.
Design/methodology/approach
Under the conditions of relative humidity 85−90% and temperature 28°C−38°C, the influence of new passive modified atmosphere packaging on the shelf life and quality of 70% ripe peaches was studied in the paper. The effect of the new passive modified atmosphere packaging (PMAP) on fruit appearance, colour, taste, flavour, soluble solids, Vitamin C and titratable acid was investigated.
Findings
Regardless of whether 1-Methylcyclopropene is added or not, the research results show that the new PMAP has a significant effect on extending the shelf life and maintaining the quality of peaches. Compared with the control group, the shelf life of peaches treated with modified atmosphere packaging and 1-Methylcyclopropene was prolonged by 7 and 11 days, increasing the retailer's revenue by 44 and 75%.
Originality/value
A new integrated structure, which is composed of two types of films with high oxygen and high water vapour permeability was designed for the retail of peaches at room temperature. The former was mainly responsible for regulating the concentration of O2 and CO2, while the latter was for removing water vapour and regulating the relative humidity in PMAP.
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This paper aims to evaluate the dynamic performance of hybrid roller bearings under lubricant contamination.
Abstract
Purpose
This paper aims to evaluate the dynamic performance of hybrid roller bearings under lubricant contamination.
Design/methodology/approach
Some steel rollers in traditional cylindrical thrust roller bearings were replaced with ceramic rollers to assemble hybrid roller bearings. Friction experiments were conducted under lubricant contamination using alumina as the contaminant, and simultaneous vibration acceleration signals from the bearings were collected to evaluate their tribological and dynamic performance.
Findings
Under lubricant contamination, hybrid roller bearings with a sufficient number of ceramic rollers exhibit greater wear resistance compared to traditional all-steel bearings. There is a noticeable suppression of energy in both tangential and normal frequency bands of the bearings, with more pronounced suppression observed in higher frequency bands.
Originality/value
This study provides valuable insights for the development of hybrid ceramic bearings.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-08-2024-0291/
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Xudong Pei, Juan Song, Na Li and Borui Cao
It is found that previous studies only focus on how digital transformation contributes to individual firms’ green innovation performance while ignoring the important role that it…
Abstract
Purpose
It is found that previous studies only focus on how digital transformation contributes to individual firms’ green innovation performance while ignoring the important role that it plays in the spillover and diffusion of green innovations among peer firms. Therefore, this study aims to investigate the influence of focal firms’ digital transformation on the spillover of green innovation among peer firms in heavily polluting industries mediated by environmental, social and governance (ESG) performance and agency conflict. Further, this study is also expected to explore the effects of digital transformation’s green innovation spillover.
Design/methodology/approach
This study chooses 6,438 A-share heavily polluting listed firms in the stock exchanges based in Shanghai and Shenzhen in China during 2010–2020 as samples and tests the hypothesis with ordinary least squares (OLS) regression. Results prove to be robust to a battery of robustness analyses the authors performed to take care of endogeneity.
Findings
The results show that the focal firm’s digital transformation may trigger their peer firms’ green innovation spillover and prompt them to engage in green innovation activities actively. The mechanism test shows that peer firms’ ESG performance and agency conflict mediate the influence path between digital transformation and peer firms’ green innovation spillover. Finally, among heavily polluting firms with high industry competition and large scale, digital transformation’s green innovation spillover effects are more significant in conventional energy-based source control, end-of-pipe treatment and substantive green innovation.
Originality/value
This study is possible to provide a potential driving mechanism of green innovation spillovers. The findings lay a sound foundation for future research, providing important theoretical support and practical insights for digital transformation to empower heavily polluting industries to achieve green transformation and low-carbon development.