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Article
Publication date: 27 August 2019

Hui Quan, Yi Chai, Rennian Li, Guo-Yi Peng and Ying Guo

Having read previous literature about vortex pump, we noticed that mechanisms of circulating flow and its relationship with energy transition remain unclear yet. However…

Abstract

Purpose

Having read previous literature about vortex pump, we noticed that mechanisms of circulating flow and its relationship with energy transition remain unclear yet. However, this mechanism, which should be clarified, significantly influences the pump’s efficiency. To comply with the aim of investigating it, the 150WX-200-20 type pump is selected as study object in our present work.

Design/methodology/approach

Numerical simulation is conducted to formulate interactions between flow rate and geometric parameters of circulating flow with certain types of blade while experiments on inner flow are served as a witness to provide experimental confirmation of numerical results. Based on these, we coupled some parameters with the pump’s external performance to study their internal connections.

Findings

It is concluded that separatrix between circulating flow and other turbulent forms is not that clear under low flow rate. With flow increases, hydraulic losses coming of it will be dominant within the front chamber. Besides, we analogized circulating flow to vortices so as to make a quantitative analysis on its progressive evolution with changing flow, and vortices speaking for circulating flow can be divided into two groups. One is called main circulating flow vortex (hereinafter referred to as MCFV), which occurs all the time while subsidiary circulating flow vortices (hereinafter referred to as SCFV) appear in certain conditions. This context discusses the primary phase of our work with intent to follow up further with circulating flow characterized by vortices (hereinafter referred to as CFV). We confirmed that MCFV Vortex 1 (Vor1) directly influences the efficiency while SCFVs only play helping. As the flow goes to the given working condition, fluids in this pump tend to be steady with the size of CFVs getting larger and their shape being regular. Meanwhile, for MCFV Vor2 and Vor4, their geometric parameters are the key factors for efficiency. When CFVs become steady, they absorb other vortices nearby, as they have higher viscosity with the efficiency reaching its maximum.

Originality/value

The research results explore a new way to measure the circulating flow and help work out the causation of this flow pattern, which may be used to improve the vortex pump’s efficiency.

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Article
Publication date: 3 June 2019

Zhimei Yuan, Yi Guo and Xingdong Wang

The purpose of this paper is to examine the role of action visibility in moderating the relationship between firm response and individual legitimacy judgment. Since a firm…

Abstract

Purpose

The purpose of this paper is to examine the role of action visibility in moderating the relationship between firm response and individual legitimacy judgment. Since a firm may decouple its public commitment from its actual practice to cope with conflicting stakeholder interests, visibility is important for consumers to make judgment because it is difficult for them to observe a firm’s actual fulfillment of its public commitment to quality assurance after a product-harm crisis.

Design/methodology/approach

Scenario-based mixed design experiments were employed and 718 valid responses were collected.

Findings

The results indicated that, while acknowledging responsibility produced more favorable legitimacy judgment than denial, decoupling produced no better judgment than denial. However, higher visibility significantly amplified the effect size. Specifically, under the condition of high visibility, not only did acknowledging responsibility produce much more favorable judgment than denial, but so did decoupling.

Research limitations/implications

This study provided empirical evidence that action visibility moderated the relationship between firm response and individual legitimacy judgment, thus complementing the literature on crisis management.

Practical implications

This study provided executives or managers with optimal, suboptimal and least optimal response strategies under different levels of action visibility.

Originality/value

Much of the extant research on response strategy for organizations to deal with product-harm crisis ignored the moderating role of action visibility. Past research on legitimacy judgment focused on organization. This paper combined firm response, action visibility and individual-level legitimacy judgment.

Details

American Journal of Business, vol. 34 no. 2
Type: Research Article
ISSN: 1935-5181

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Article
Publication date: 13 March 2019

Guo Yi, Junhua Xu and Chuanbo Zheng

There are obvious differences in corrosion resistance of different 2205 welding joints with different ratios of austenite and ferrite, from the top to the bottom, the…

Abstract

Purpose

There are obvious differences in corrosion resistance of different 2205 welding joints with different ratios of austenite and ferrite, from the top to the bottom, the austenite content decreased gradually while the ferrite increased. In each region of welded joint, the pitting resistance number of ferrite is higher than that of austenite; pitting corrosion is more likely to occur in austenite phase first on the top region of the weld and in the secondary phase precipitates on the other regions of the weld. The fluctuation of the ratio of austenite and ferrite has a great influence on performance of passive film in 3.5 per cent NaCl solution.

Design/methodology/approach

To study the corrosion behavior of welded joint, the samples were obtained by laser hybrid welding. Pitting corrosion was studied in different area of welded joint. The Mott–Schottky curves of welded joints were measured to study the passive film on the different welded joint area.

Findings

Due to the difference of heat input and the limit of filler depth of the wire, the microstructure of duplex stainless steel laser welding joint has obvious difference in the thickness direction. In addition, there will be harmful secondary phase (such as chromium nitride and σphase) precipitates in the lower part of the joint. For the welded joint, the corrosion resistance decreases with the increase in the difference of the microstructure. Pitting corrosion usually takes the two phases as the nucleation point and grows up. The surface of 2205 duplex stainless steel laser hybrid welding joint cannot form a complete passive film in 3.5 per cent NaCl solution, and the more the ratios of austenite and ferrite deviate from equilibrium position (50:50), the worse the performance of passive film is.

Originality/value

In this paper, the authors attempt to establish the correlation between the semiconductor electronic properties of passive film and the difference of microstructures and the component in a joint welded by laser hybrid welding. The effect of passive film on the corrosion resistance of the weld was further investigated.

Details

Anti-Corrosion Methods and Materials, vol. 66 no. 3
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 9 November 2020

Saleha Noor, Yi Guo, Syed Hamad Hassan Shah, Philippe Fournier-Viger and M. Saqib Nawaz

The novel Coronavirus (COVID-19) pandemic, which started in late December 2019, has spread to more than 200 countries. As no vaccine is yet available for this pandemic…

Abstract

Purpose

The novel Coronavirus (COVID-19) pandemic, which started in late December 2019, has spread to more than 200 countries. As no vaccine is yet available for this pandemic, government and health agencies are taking draconian steps to contain it. This pandemic is also trending on social media, particularly on Twitter. The purpose of this study is to explore and analyze the general public reactions to the COVID-19 outbreak on Twitter.

Design/methodology/approach

This study conducts a thematic analysis of COVID-19 tweets through VOSviewer to examine people’s reactions related to the COVID-19 outbreak in the world. Moreover, sequential pattern mining (SPM) techniques are used to find frequent words/patterns and their relationship in tweets.

Findings

Seven clusters (themes) were found through VOSviewer: Cluster 1 (green): public sentiments about COVID-19 in the USA. Cluster 2 (red): public sentiments about COVID-19 in Italy and Iran and a vaccine, Cluster 3 (purple): public sentiments about doomsday and science credibility. Cluster 4 (blue): public sentiments about COVID-19 in India. Cluster 5 (yellow): public sentiments about COVID-19’s emergence. Cluster 6 (light blue): public sentiments about COVID-19 in the Philippines. Cluster 7 (orange): Public sentiments about COVID-19 US Intelligence Report. The most frequent words/patterns discovered with SPM were “COVID-19,” “Coronavirus,” “Chinese virus” and the most frequent and high confidence sequential rules were related to “Coronavirus, testing, lockdown, China and Wuhan.”

Research limitations/implications

The methodology can be used to analyze the opinions/thoughts of the general public on Twitter and to categorize them accordingly. Moreover, the categories (generated by VOSviewer) can be correlated with the results obtained with pattern mining techniques.

Social implications

This study has a significant socio-economic impact as Twitter offers content posting and sharing to billions of users worldwide.

Originality/value

According to the authors’ best knowledge, this may be the first study to carry out a thematic analysis of COVID-19 tweets at a glance and mining the tweets with SPM to investigate how people reacted to the COVID-19 outbreak on Twitter.

Details

Kybernetes, vol. 50 no. 5
Type: Research Article
ISSN: 0368-492X

Keywords

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Article
Publication date: 10 May 2018

Guo Yi, Jianxu Mao, Yaonan Wang, Hui Zhang and Zhiqiang Miao

The purpose of this paper is to consider the leader-following formation control problem for nonholonomic vehicles based on a novel biologically inspired neurodynamics approach.

Abstract

Purpose

The purpose of this paper is to consider the leader-following formation control problem for nonholonomic vehicles based on a novel biologically inspired neurodynamics approach.

Design/methodology/approach

The interactions among the networked multi-vehicle system is modeled by an undirected graph. First, a distributed estimation law is proposed for each follower vehicle to estimate the state including the position, orientation and linear velocity of the leader. Then, a distributed formation tracking control law is designed based on the estimated state of the leader, where a bio-inspired neural dynamic is introduced to solve the impractical velocity jumps problem. Explicit stability and convergence analyses are presented using Lyapunov tools.

Findings

The effectiveness and efficiency of the proposed control law are demonstrated by numerical simulations and physical vehicle experiments. Consequently, the proposed protocol can successfully achieve the desired formation under connected topologies while tracking the trajectory generated by the leader.

Originality/value

This paper proposes a neurodynamics-based leader–follower formation tracking algorithm for multiple nonholonomic vehicles.

Details

Assembly Automation, vol. 38 no. 5
Type: Research Article
ISSN: 0144-5154

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Article
Publication date: 16 March 2020

Muhamad Husnain Mohd Noh, Mohd Akramin Mohd Romlay, Chuan Zun Liang, Mohd Shamil Shaari and Akiyuki Takahashi

Failure of the materials occurs once the stress intensity factor (SIF) overtakes the material fracture toughness. At this level, the crack will grow rapidly resulting in…

Abstract

Purpose

Failure of the materials occurs once the stress intensity factor (SIF) overtakes the material fracture toughness. At this level, the crack will grow rapidly resulting in unstable crack growth until a complete fracture happens. The SIF calculation of the materials can be conducted by experimental, theoretical and numerical techniques. Prediction of SIF is crucial to ensure safety life from the material failure. The aim of the simulation study is to evaluate the accuracy of SIF prediction using finite element analysis.

Design/methodology/approach

The bootstrap resampling method is employed in S-version finite element model (S-FEM) to generate the random variables in this simulation analysis. The SIF analysis studies are promoted by bootstrap S-version Finite Element Model (BootstrapS-FEM). Virtual crack closure-integral method (VCCM) is an important concept to compute the energy release rate and SIF. The semielliptical crack shape is applied with different crack shape aspect ratio in this simulation analysis. The BootstrapS-FEM produces the prediction of SIFs for tension model.

Findings

The mean of BootstrapS-FEM is calculated from 100 samples by the resampling method. The bounds are computed based on the lower and upper bounds of the hundred samples of BootstrapS-FEM. The prediction of SIFs is validated with Newman–Raju solution and deterministic S-FEM within 95 percent confidence bounds. All possible values of SIF estimation by BootstrapS-FEM are plotted in a graph. The mean of the BootstrapS-FEM is referred to as point estimation. The Newman–Raju solution and deterministic S-FEM values are within the 95 percent confidence bounds. Thus, the BootstrapS-FEM is considered valid for the prediction with less than 6 percent of percentage error.

Originality/value

The bootstrap resampling method is employed in S-FEM to generate the random variables in this simulation analysis.

Details

International Journal of Structural Integrity, vol. 11 no. 4
Type: Research Article
ISSN: 1757-9864

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Article
Publication date: 7 March 2019

Hui-Wen Deng and Kwok Wah Cheung

The National People’s Congress (NPC) of People’s Republic of China, the highest organ of state power, is popularly seen as a rubber-stamp entity. However, it has been…

Abstract

Purpose

The National People’s Congress (NPC) of People’s Republic of China, the highest organ of state power, is popularly seen as a rubber-stamp entity. However, it has been substantially evolving its roles to accommodate the governance discourses within China’s political system over the decades. This study aims to explore the changes of governance discourse of the NPC within China’s political system through which to offer a thorough understanding of the NPC’s evolving substantial role in current China.

Design/methodology/approach

This study deploys a historical approach to explore the changes of governance discourse of the NPC that has seen a growing importance in China’s political agenda, as argued by this study.

Findings

The authors find that the NPC has been substantially evolving its role within China’s political system in which the Chinese Communist Party has created different governance discourses. Besides, the NPC and its Standing Committee have asserted its authority as a substantial actor within China’s political system. The NPC is no longer functioned as a rubber-stamp institution, though it is still popularized as a rubber stamp by many scholars.

Research limitations/implications

This study is a historical elaboration on the development of NPC under three governance discourses. It might be, to some extent, relatively descriptive in nature.

Originality/value

This study, therefore, sheds some light on a revisit on the governance discourses in current China.

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Book part
Publication date: 16 September 2014

Mian Wang and Yajing Feng

Special education in China has lagged behind regular education for many years, however, the past few decades, the government has made considerable efforts to develop and…

Abstract

Special education in China has lagged behind regular education for many years, however, the past few decades, the government has made considerable efforts to develop and improve the special education system. While the citizens of China have had a generic moral interest in disability since ancient times, the development of special education schools did not occur until American and European missionaries started schools for the visually and hearing impaired in the 19th century. The next major influence in the development of the special education system occurred with China’s Cultural Revolution in 1978. Interestingly, there is not any exclusive legislation on special education but in the 1980s, the government started Learning in Regular Classrooms (LRC), which is China’s version of inclusion. LRC has progressed rapidly the past two decades; however, the quality of instruction is low due to a lack of specialists, a shortage of personnel, inadequate funding, and limited technology as well as other barriers that are delineated in the chapter. The chapter emphasizes the government’s recent efforts in in-service teacher training, the preparation of preservice teachers, working with families, developing community rehabilitation training programs, and implementing evidence-based practices. Special education in China today is at a good place but it has quite a way from the ideal situation.

Details

Special Education International Perspectives: Practices Across the Globe
Type: Book
ISBN: 978-1-78441-096-4

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Article
Publication date: 1 November 1999

Victor H.Y. Lo

Considers TQM from a cultural perspective using the influence of Confucian work dynamism and Chinese cultural beliefs on Hong Kong companies. Asks if these cultural…

Abstract

Considers TQM from a cultural perspective using the influence of Confucian work dynamism and Chinese cultural beliefs on Hong Kong companies. Asks if these cultural beliefs conflict with modern quality management philosophy and presents the findings of research covering Chinese literature, experts in Chinese philosophy and Hong Kong TQM experts. Outlines research methods and concludes that there are relevant principles which can be used when implementing TQM.

Details

Management Research News, vol. 22 no. 11
Type: Research Article
ISSN: 0140-9174

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Article
Publication date: 24 August 2010

Yi‐nan Guo, Mei Yang and Da‐wei Xiao

The purpose of this paper is to find a novel optimization selection method for hyper‐parameter of support vector classification (SVC), responsible for the classification…

Abstract

Purpose

The purpose of this paper is to find a novel optimization selection method for hyper‐parameter of support vector classification (SVC), responsible for the classification of datasets from the UCI machine learning database repository.

Design/methodology/approach

A novel two‐stage optimization selection method for hyper‐parameters is proposed. It makes use of explicit information derived from issues and implicit knowledge extracted from the evolution process so as to improve the performance of classifier. In the first stage, the search extent of each hyper‐parameter is determined according to the requirements of issues. In the second stage, optimal hyper‐parameters are obtained by adaptive chaotic culture algorithm in the above search extent. Adaptive chaotic cultural algorithm uses implicit knowledge extracted from the evolution process to control mutation scale of chaotic mutation operator. This algorithm can ensure the diversity of population and exploitation in the latter evolution.

Findings

The rationality of the above optimization selection method is proved by the binary classification problem. Final confirmation of this approach is the classification results compared with other methods.

Originality/value

This optimization selection method can effectively avoid premature convergence and lead to better computation stability and precision. It is not related on the structure of functions. SVC model corresponding to optimal hyper‐parameters by this method has better generalization.

Details

International Journal of Intelligent Computing and Cybernetics, vol. 3 no. 3
Type: Research Article
ISSN: 1756-378X

Keywords

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