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The purpose of this paper is to investigate the effect of nanofluid over rotating disk with the exponential variable thickness Z=ce−bRR0 (c > 0, b > 0) and to analyze Brownian motion and thermophoresis of Buongiorno model on the disk embedded in nanofluid-saturated porous media.

Using the generalized von Karman transformation, the boundary layer governing equations are transformed into semi-similar forms solved by bvp4c in MATLAB.

The effects of the thickness parameter a, the shape parameter b, the Brownian motion parameter Nb and thermophoresis parameter Nt on flow, heat and mass transfer are analyzed. With the increase of thickness parameter a, the radial velocity first decreases and then increases, showing the opposite trend on the two sides of the peak value. Moreover, temperature and concentration rise as the Brownian motion parameter Nb becomes larger.

To the best of the authors’ knowledge, this is the first work that has been done on rotating disk with exponential variable thickness in nanofluid. The impact of the two slip effects, namely, Brownian motion and thermophoresis, on the nanofluid boundary layer flow, heat and mass transfer because of rotating disk with exponential variable thickness Z=ce−bRR0 (c > 0, b > 0) has been addressed in this study.

At present, one of the key equipment in pillar industries is a large rotating machinery. Conducting regular health monitoring is important for ensuring safe operation of the large rotating machinery. Because vibrations sensors play an important role in the workings of the rotating machinery, measuring its vibration signal is an important task in health monitoring. This paper aims to present these.

In this work, the contact vibration sensor and the non-contact vibration sensor have been discussed. These sensors consist of two types: the electric vibration sensor and the optical fiber vibration sensor. Their applications in the large rotating machinery for the purpose of health monitoring are summarized, and their advantages and disadvantages are also presented.

Compared with the electric vibration sensor, the optical fiber vibration sensor of large rotating machinery has unique advantages in health monitoring, such as provision of immunity against electromagnetic interference, requirement of less insulation and provision of long-distance signal transmission.

Both contact vibration sensor and non-contact vibration sensor have been discussed. Among them, the electric vibration sensor and the optical fiber vibration sensor are compared. Future research direction of the vibration sensors is presented.

The paper seeks to attempt to solve a decision‐making problem for breeding target character shown as an interval number.

A new comprehensive evaluation method is proposed based on similarity‐difference theory and interval number theory. Data from Winter Wheat Group I Variety Regional Test in Henan Province in 2009‐2010 were analysed using the proposed method.

The results showed that Zhou 99233 was a good variety; Yuxhan No. 7, An 05‐28, Xun K8, Jinyumai 378 and Zhoumai 18 were better ones; 08 luo 36,and Xuke 718 ordinary ones, and others worse ones. Based on this, the feasibility of the method was discussed. It showed that the proposed method had some obvious merits, such as simple arithmetic, convenient operation, flexible and practical, fast and effective.

The application of a live example indicated that its evaluation effect was satisfactory.

The paper succeeds in solving a decision‐making problem for breeding target character shown as an interval number.

The purpose of the paper is to make a high speed motor based on the characteristics of high strength silicon steel. With the higher requirements for torque density and power density of the driving system of electric vehicles (EV), conventional magnetic materials have been difficult to meet the demands in the future. In this paper, a new type of high-strength non-grain-oriented (NGO)material is tested.

Through analyzing the characteristic of high strength silicon steel, it is applied to the rotor part of a high-speed motor. A topological optimization is applied to achieve higher power density and higher efficiency of the motor.

The feasibility of the scheme was analyzed by the finite element method, and a prototype was also fabricated to verify the analysis.

In this paper, the characteristics of new soft magnetic materials as a breakthrough to manufacture a new generation of high-performance electrical machine (EM) are discussed. Consequently, the presented work greatly facilitates further explorations and guides the innovative application of soft magnetic materials and the iterative optimization of motor structure.

Although researchers have demonstrated a significant interest in motivation factors of knowledge collaboration, previous studies have seldom explored the dynamic interrelations in virtual communities of practice (VCoPs) over time that involve the iteratively melding of knowledge collaboration motivations and behaviours. Therefore, this study aims to unveil the interactive dynamics amongst motivation factors of knowledge collaboration in VCoPs from a perspective of system dynamics (SD).

According to the SD method proposed by Forrester, this paper develops an SD model of motivation factors of knowledge collaboration in VCoP by identifying interactions of motivation factors based on behavioural theories, validating the proposed model by structural tests and behaviour tests involving historical data from 939 Wikipedians and analysing the impacts of policy regulations on knowledge collaboration behaviours in Wikipedia.

In accordance with current literature, this study categorises intrinsic, extrinsic and community motivation factors of knowledge collaborations in VCoPs. According to the SD method, this study develops and validates an SD model to reveal interesting non-linear dynamics of these motivation factors which are neglected by prior studies. This study also conducts dynamic what-if analyses to suggest policy regulations to promote knowledge collaborations in the context of Wikipedia.

Different from prior empirical studies which normally take on a snapshot of motivation factors, this study discloses a dynamic picture of their interrelations by unfolding their behaviour patterns over time. The main contribution of this paper is to develop and validate an SD model of motivation factors of knowledge collaboration in VCoP and to reveal and elaborate their dynamics for policy regulations in VCoPs based on simulation results.

Grappling with the sweeping pandemic, the small hospitality business (SHB), smaller in scale and weaker in risk mitigation, has been seriously affected. The purpose of this study aims to supplement the unrepresented area of SHB in China from the digital perspective by drawing on instrumentalization theory (IT).

Based on two appropriate and detailed SHB cases, this paper adopted a qualitative approach to understand and conceptualize the focal issue.

This study identified the factors affecting SHB at operational, managerial and transformational levels amidst the crisis. It further developed a theoretical framework of the SHB rebound matrix, highlighting the importance of digitization and digitalization.

The research theoretically confirmed that SHB is internally, externally and essentially restricted and developed a corresponding rebound matrix. It practically supports SHB’s transformation by making recommendations to unleash the potential of digital business.

This study complements extant descriptive and atheoretical research by focusing on SHB’s underlying digital nature through the lens of IT, providing an evidenced theoretical understanding of SHB’s development amidst and after the pandemic.

Despite grave public concerns over information privacy and ongoing academic explorations of privacy policy, there is a general lack of understanding toward this issue in the legal context in China, the largest e-commerce market in the world. Departing from the extant literature of general discussion in nature, the authors undertook an exploratory study on the efficacy of e-commerce websites' privacy policies in China from the legal perspective.

The authors drew on a qualitative grounded theory approach to identify selective codes relating to the focal issue and established a theoretical framework therefrom. The authors then conducted theoretical integration by linking them to the Theory of Development Blocks and the System Justification Theory.

The research identifies a general distrust of Chinese consumers toward privacy policies and highlights that despite their growing concerns about privacy, the privacy policies are largely ineffective in reflecting legal enforcement, changing their perceptions or influencing purchase behaviors. It also reveals that the current Chinese legislation is unable to fully render consumers' confidence in e-commerce websites' privacy policies effectiveness and privacy protection due to its limited recognition and influences among them.

The research has multiple ramifications. The authors empirically confirmed a mismatch between customers' perception of privacy policies and their actual behaviors and then theoretically explained the seemingly conflicting scenario in the context of development block of legal enforcement and system justification. The authors theorized the absence of the legal enforcement in privacy policies to supplement the legal perspective to the literature. The research further leads us to suggest that the time has come to update and strongly enforce privacy regulation in China to fuel the further development of e-commerce sector in practice.

The dispute over the benefit of diversity on the transactive memory system (TMS) has attracted the attention with the development of global collaboration. This paper aims to discover how knowledge heterogeneity (KH), categorized as explicit and tacit KH, affects TMS and to test the mediation effect of innovation climate (IC).

Data from a 6-month field study of 207 research and development (R&D) members and 7 expertize observers were analyzed by partial least squares structure equation model. Robustness check and Barron and Kenny mediation test were used to evaluate the model and confirm the mediation effect.

Tacit KH of R&D team negatively influences the development of TMS. Furthermore, IC partially mediates tacit KHs’ negative influence on the development of TMS.

These results distinguish the different influence of explicit and tacit KH on TMS and explore the mediating role of IC that has been confirmed affecting the development of TMS.

These results could motivate practitioners to address more attention to tacit KH, IC and the development of TMS in the R&D team members composition.

This study contributes not only to elucidate the different influence of explicit and tacit KH on TMS but also to the appropriate members composition of R&D team by considering the relationships among KH, IC, TMS and innovation performance.

Grey modeling technique is an important element of grey system theory, and academic articles applied to agricultural science research have been published since 1985, proving the broad applicability and effectiveness of the technique from different aspects and providing a new means to solve agricultural science problems. The analysis of the connotation and trend of the application of grey modeling technique in agricultural science research contributes to the enrichment of grey technique and the development of agricultural science in multiple dimensions.

Based on the relevant literature selected from China National Knowledge Infrastructure, the Web of Science, SpiScholar and other databases in the past 37 years (1985–2021), this paper firstly applied the bibliometric method to quantitatively visualize and systematically analyze the trend of publication, productive author, productive institution, and highly cited literature. Then, the literature is combed by the application of different grey modeling techniques in agricultural science research, and the literature research progress is systematically analyzed.

The results show that grey model technology has broad prospects in the field of agricultural science research. Agricultural universities and research institutes are the main research forces in the application of grey model technology in agricultural science research, and have certain inheritance. The application of grey model technology in agricultural science research has wide applicability and precise practicability.

By analyzing and summarizing the application trend of grey model technology in agricultural science research, the research hotspot, research frontier and valuable research directions of grey model technology in agricultural science research can be more clearly grasped.

The sudden COVID-19 epidemic in 2019 has frustrated China's overall economy, and the implementation and development of the National Fitness Program has encountered huge obstacles. At a new historical starting point, in order to realize the dream of becoming a powerful country in sports, it is necessary to transform the successful experience gained since the reform and opening up into regular understanding and systematic theories, so as to make a theoretical response to the new contradictions and challenges faced in development and give full play to the National Fitness has comprehensive values and multiple functions in improving people's health, promoting people's all-round development, promoting economic and social development and demonstrating the country's cultural soft power.

Taking the topic of national fitness as an example, this paper sets out from the three dimensions of knowledge input, knowledge output and knowledge production, using citation analysis, social network analysis, co-word analysis and cluster analysis, to measure the characteristics and knowledge structure of interdisciplinary knowledge exchange.

China's national fitness is still in the primary development stage, and the strong boost of the national top-level policy is the biggest driving force of its development, driven by the policy together with the settlement of many major events, constantly improving and enriching the wings. The main body of knowledge production on the topic of national fitness is mainly colleges and universities, with low participation of government and enterprises, high degree of cooperation among authors, obvious interdisciplinary characteristics and strong application of research themes.

This study provides a strong theoretical basis for the promotion of the Healthy China strategy. Especially under the influence of COVID-19, this paper can contribute to the comprehensive value and multimodal functions of national fitness in improving the health of people, promoting economic and social development and demonstrating the soft power of national culture.