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Available. Open Access. Open Access
Article
Publication date: 14 November 2023

Leiting Zhao, Kan Liu, Donghui Liu and Zheming Jin

This study aims to improve the availability of regenerative braking for urban metro vehicles by introducing a sensorless operational temperature estimation method for the braking…

238

Abstract

Purpose

This study aims to improve the availability of regenerative braking for urban metro vehicles by introducing a sensorless operational temperature estimation method for the braking resistor (BR) onboard the vehicle, which overcomes the vulnerability of having conventional temperature sensor.

Design/methodology/approach

In this study, the energy model based sensorless estimation method is developed. By analyzing the structure and the convection dissipation process of the BR onboard the vehicle, the energy-based operational temperature model of the BR and its cooling domain is established. By adopting Newton's law of cooling and the law of conservation of energy, the energy and temperature dynamic of the BR can be stated. To minimize the use of all kinds of sensors (including both thermal and electrical), a novel regenerative braking power calculation method is proposed, which involves only the voltage of DC traction network and the duty cycle of the chopping circuit; both of them are available for the traction control unit (TCU) of the vehicle. By utilizing a real-time iterative calculation and updating the parameter of the energy model, the operational temperature of the BR can be obtained and monitored in a sensorless manner.

Findings

In this study, a sensorless estimation/monitoring method of the operational temperature of BR is proposed. The results show that it is possible to utilize the existing electrical sensors that is mandatory for the traction unit’s operation to estimate the operational temperature of BR, instead of adding dedicated thermal sensors. The results also validate the effectiveness of the proposal is acceptable for the engineering practical.

Originality/value

The proposal of this study provides novel concepts for the sensorless operational temperature monitoring of BR onboard rolling stocks. The proposed method only involves quasi-global electrical variable and the internal control signal within the TCU.

Available. Open Access. Open Access
Article
Publication date: 12 December 2024

Leiting Zhao, Yongxiang Wang, Kan Liu, Liran Li, Jingyuan Zhan and Qingliang Liu

This study aims to propose a cooperative adhesion control method for trains with multiple motors electric locomotives. The method is intended to optimize the output torque of each…

33

Abstract

Purpose

This study aims to propose a cooperative adhesion control method for trains with multiple motors electric locomotives. The method is intended to optimize the output torque of each motor, maximize the utilization of train adhesion within the total torque command, reduce the train skidding/sliding phenomenon and achieve optimal adhesion utilization for each axle, thus realizing the optimal allocation of the multi-motor electric locomotives.

Design/methodology/approach

In this study, a model predictive control (MPC)-based cooperative maximum adhesion tracking control method for multi-motor electric locomotives is presented. Firstly, train traction system with multiple motors is constructed in accordance with Newton’s second law. These equations include the train dynamics equations, the axle dynamics equations, and the wheel-rail adhesion coefficient equations. Then, a new MPC-based multi-axle adhesion co-optimization method is put forward. This method calculates the optimal output torque through real-time iteration based on the known reference slip speed to achieve multi-axle co-optimization under different circumstances.

Findings

This paper presents a MPC system designed for the cooperative control of multi-axle adhesion. The results indicate that the proposed control system is able to optimize the adhesion of multiple axles under numerous different conditions and achieve the optimal power distribution based on the reduction of train skidding/sliding.

Originality/value

This study presents a novel cooperative adhesion tracking control scheme. It is designed for multi-motor electric locomotives, which has rarely been studied before. And simulations are carried out in different conditions, including variable surfaces and motor failing.

Details

Railway Sciences, vol. 4 no. 1
Type: Research Article
ISSN: 2755-0907

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Article
Publication date: 29 August 2022

Yue Yuan, Kan Liu and Yanli Wang

The purpose of this study is to analyze the topics of COVID-19 news articles for better obtaining the relationship among and the evolution of news topics, helping to manage the…

350

Abstract

Purpose

The purpose of this study is to analyze the topics of COVID-19 news articles for better obtaining the relationship among and the evolution of news topics, helping to manage the infodemic from a quantified perspective.

Design/methodology/approach

To analyze COVID-19 news articles explicitly, this paper proposes a prism architecture. Based on epidemic-related news on China Daily and CNN, this paper identifies the topics of the two news agencies, elucidates the relationship between and amongst these topics, tracks topic changes as the epidemic progresses and presents the results visually and compellingly.

Findings

The analysis results show that CNN has a more concentrated distribution of topics than China Daily, with the former focusing on government-related information, and the latter on medical. Besides, the pandemic has had a big impact on CNN and China Daily's reporting preference. The evolution analysis of news topics indicates that the dynamic changes of topics have a strong relationship with the pandemic process.

Originality/value

This paper offers novel perspectives to review the topics of COVID-19 news articles and provide new understandings of news articles during the initial outbreak. The analysis results expand the scope of infodemic-related studies.

Details

Aslib Journal of Information Management, vol. 75 no. 2
Type: Research Article
ISSN: 2050-3806

Keywords

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Article
Publication date: 27 September 2024

Kan Liu, Ziyi Zhang and Hongrui Zhou

Exploring open value, cultivating digital capability (DC) and driving business model innovation (BMI) have become an inevitable choice for enterprises to meet market demand and…

106

Abstract

Purpose

Exploring open value, cultivating digital capability (DC) and driving business model innovation (BMI) have become an inevitable choice for enterprises to meet market demand and adapt to environmental changes. However, as one of the situational variables of BMI, the positive or negative influence of openness has not been proved and the path mechanism between DC and BMI is not clear. Based on the dynamic capability theory, this paper takes manufacturing enterprises as an example to explore the internal impact mechanisms of organizational openness on BMI. It extends the analysis by introducing DC as a mediating variable and introducing manufacturing enterprise type (high-tech and non-high-tech) as a moderating variable.

Design/methodology/approach

A questionnaire survey was conducted using data collected in China, data from 355 manufacturing enterprises were collected to carry out empirical research. Participants were mainly middle and senior managers with a comprehensive grasp of their firms’ information. Exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) were used to test the reliability and validity of the sample data, and negative binomial regression analysis was used to test hypothesis relationships.

Findings

The authors find an inverted U-shaped relationship between openness and BMI, and explain that excessive openness may lead to low resource utilization, organizational inertia, cooperation distrust, which will have a negative impact on BMI. DC includes digital resource capability (DRC), digital management capability (DMC) and digital collaboration capability (DCC), which promote BMI and play a mediating role between openness and BMI. Enterprise type has a moderating effect on the relationship between DC and BMI.

Research limitations/implications

The results of this paper summarize the opportunities and threats of open innovation, help enterprises fully understand the double-edged sword impact of openness, guide manufacturing enterprises to be sensitive to openness and achieve sustainable innovation. By analyzing the path of DRC, DMC and DCC to BMI, managers can improve their understanding of digital-driven value creation process and improve the competitive advantage of enterprises.

Originality/value

This paper presents the relationships among openness, DC and BMI. We find the non-linear effects of openness on DC and BMI, bridging the inconsistent view of positive or negative relationship between openness and organizational change in previous studies. The introduction of DC extends the theory of dynamic capability in the digital age, and opens the “black box” from opening to BMI from the process perspective of DRC, DMC and DCC. From the perspective of enterprise type, this paper provides different choices of capability upgrading and strategic innovation based on openness for high-tech and non-high-tech manufacturing enterprises.

Details

Journal of Organizational Change Management, vol. 38 no. 1
Type: Research Article
ISSN: 0953-4814

Keywords

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Article
Publication date: 16 August 2021

Mengxi Yang, Wansi Chen, Qingyu Zhou, Baiyin Yang and Cheng Xu

China after 1949, especially since entering the 21st century, significant progress has been made in leadership research under Chinese context. However, so far there has been no…

625

Abstract

Purpose

China after 1949, especially since entering the 21st century, significant progress has been made in leadership research under Chinese context. However, so far there has been no systematic review and prospect of China's leadership research in the past 70 years. Therefore, with the help of scientific visualization software Citespace, this paper analyzes the research papers on leadership in the context of China from the top international journals of management science and applied psychology (1949–2018), supplemented and verified the previous research conclusions based on qualitative review, and quantitatively demonstrated the research evolution of leadership field.

Design Methodology Approach

Using a scientific visualization tool CiteSpace and 145 international leadership works, which were published in 64 top international journals and collected from the Web of Science database, and 852 domestic works which were published in 28 top domestic journals and collected from the CNKI database from 1949 to 2018, we draws keyword co-occurrence knowledge graph and keyword strategy map to visualize the landscape and evolution of leadership research and analyze the hot topics and research trends in the field of leadership.

Findings

The research found that: (1) Before 2002, there were only 7 articles published in 64 international top journal, mainly focusing on Western leadership theories such as transformational, cross-cultural comparison and the adaptability in Chinese context; (2) From 2003 to 2012, scholars had begun to introduce mainstream quantitative research paradigm in international academic community; (3) From 2013 to 2018, researches tended to be synchronized, with 461 and 99 papers published respectively. How emerging leaderships (such as ethical leadership) affect on various emerging outcome variables (such as creativity, voice behavior, unethical pro-organizational behavior etc.) is hot topic for future research.

Originality Value

Different from the previous qualitative reviews on organizational culture research, this paper, for the first time, uses bibliometric research methods to systematically analyze the evolution path of leadership research during the 70 years of China(1949–2018, and puts forward the future research prospects.

Details

Nankai Business Review International, vol. 13 no. 1
Type: Research Article
ISSN: 2040-8749

Keywords

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Article
Publication date: 20 November 2024

Ignasius Radix A.P. Jati, Michael Angelo Kamaluddin, Adrianus Rulianto Utomo, Erni Setijawaty, Edward Edward and David Tjandra Nugraha

This study aims to investigate the application of red cabbage extract in biodegradable composite-based edible film and evaluate its physicochemical characteristics and ability to…

19

Abstract

Purpose

This study aims to investigate the application of red cabbage extract in biodegradable composite-based edible film and evaluate its physicochemical characteristics and ability to be used in steamed chicken packaging.

Design/methodology/approach

Cassava starch, gelatin and glycerol were used as basic materials for edible film. Red cabbage extract was infused, and eggshell powder was also incorporated. The smart edible film formulation consists of six treatments which are C (control: cassava starch + gelatin + glycerol), CE (control + 0.1% eggshell powder), CRA (control + red cabbage A ratio), CERA (control + 0.1% eggshell powder + red cabbage A ratio), CERB (control + 0.1% eggshell powder + red cabbage B ratio) and CERC (control + 0.1% eggshell powder + red cabbage C ratio).

Findings

The different ratios of red cabbage extract in the formulation of the edible film affected its physicochemical properties (p < 0.05). The range of anthocyanin content were 0.39–11.53 mg cy-3-glu-eq/100 g and phenolic content were 19.87–369.68 mg GAE/100 g. Meanwhile, the antioxidant activity was 12.35%–51.09%. The tensile strength in all treatments was lower than control and adding red cabbage extract decreased the tensile strength. On the other hand, the elongation increased. The water vapor transmission rate was ranged from 158.09 to 191.19 g/m2/24 h. Morphological changes can be observed from scanning electron microscopy and optical data. Furthermore, using steamed chicken as a model, the edible film can show a response through the changes in edible film color, as confirmed by the pH value, total plate count and sensory quality of the stored steamed chicken.

Originality/value

There is no report available on the infusion of red cabbage extract on the bio composite edible film materials. The result shows a promising packaging material that can be used as an alternative to plastic packaging.

Details

Nutrition & Food Science, vol. 55 no. 2
Type: Research Article
ISSN: 0034-6659

Keywords

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Article
Publication date: 17 January 2022

Xintian Liu, Que Wu, Shengchao Su and Yansong Wang

The properties of materials under impact load are introduced in terms of metal, nonmetallic materials and composite materials. And the application of impact load research in…

692

Abstract

Purpose

The properties of materials under impact load are introduced in terms of metal, nonmetallic materials and composite materials. And the application of impact load research in biological fields is also mentioned. The current hot research topics and achievements in this field are summarized. In addition, some problems in theoretical modeling and testing of the mechanical properties of materials are discussed.

Design/methodology/approach

The situation of materials under impact load is of great significance to show the mechanical performance. The performance of various materials under impact load is different, and there are many research methods. It is affected by some kinds of factors, such as the temperature, the gap and the speed of load.

Findings

The research on mechanical properties of materials under impact load has the characteristics as fellow. It is difficult to build the theoretical model, verify by experiment and analyze the data accumulation.

Originality/value

This review provides a reference for further study of material properties.

Details

International Journal of Structural Integrity, vol. 13 no. 2
Type: Research Article
ISSN: 1757-9864

Keywords

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Article
Publication date: 31 July 2024

Luciana Londero Brandli, Giovana Reginatto, Amanda Lange Salvia and Pedro Henrique Carretta Diniz

This paper aims to describe the academic community’s perspectives about climate change learning and engagement opportunities by means of a case study at the University of Passo…

85

Abstract

Purpose

This paper aims to describe the academic community’s perspectives about climate change learning and engagement opportunities by means of a case study at the University of Passo Fundo, Brazil.

Design/methodology/approach

A set of interviews and focus groups were conducted, and data collection focused on three main groups, namely, university students, professors and managers. The analysis was developed through content analysis of the individual interviews and focus groups.

Findings

The results showed that the academic community is trying to change their attitudes and behaviours, and students would like to learn more about climate change.

Originality/value

This investigation combines the views of different academic groups and indicates initiatives that could boost the university initiatives towards climate action and learning.

Details

International Journal of Sustainability in Higher Education, vol. 26 no. 2
Type: Research Article
ISSN: 1467-6370

Keywords

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Article
Publication date: 8 September 2023

Xintian Liu and Muzhou Ma

Scholars mainly propose and establish theoretical models of cumulative fatigue damage for their research fields. This review aims to select the applicable model from many fatigue…

274

Abstract

Purpose

Scholars mainly propose and establish theoretical models of cumulative fatigue damage for their research fields. This review aims to select the applicable model from many fatigue damage models according to the actual situation. However, relatively few models can be generally accepted and widely used.

Design/methodology/approach

This review introduces the development of cumulative damage theory. Then, several typical models are selected from linear and nonlinear cumulative damage models to perform data analyses and obtain the fatigue life for the metal.

Findings

Considering the energy law and strength degradation, the nonlinear fatigue cumulative damage model can better reflect the fatigue damage under constant and multi-stage variable amplitude loading. In the following research, the complex uncertainty of the model in the fatigue damage process can be considered, as well as the combination of advanced machine learning techniques to reduce the prediction error.

Originality/value

This review compares the advantages and disadvantages of various mainstream cumulative damage research methods. It provides a reference for further research into the theories of cumulative fatigue damage.

Details

International Journal of Structural Integrity, vol. 14 no. 5
Type: Research Article
ISSN: 1757-9864

Keywords

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Article
Publication date: 11 January 2021

Haijie Wang, Xintian Liu, Que Wu, Xiaolan Wang and Yansong Wang

The purpose of this paper is to obtain a more accurate fatigue life of structures by introducing the surface roughness into fatigue life prediction model.

280

Abstract

Purpose

The purpose of this paper is to obtain a more accurate fatigue life of structures by introducing the surface roughness into fatigue life prediction model.

Design/methodology/approach

Based on the fatigue life prediction model with surface roughness correction, the shock absorber cylinder is taken as an example to verify the feasibility of the improved method. Based on the load of the shock absorber cylinder during driving, fatigue experiments are performed under longitudinal and lateral forces, respectively. Then, the fatigue life predicted by the modified model is compared with that predicted by the traditional model.

Findings

By comparing with the test results, considering the influence of mean stress, the Manson method is more accurate in life prediction. Then, the modified Manson-Coffin and Manson method with surface roughness is more accurate in life prediction under longitudinal force and lateral forces, respectively. This verifies the feasibility of the improved method with the surface roughness.

Originality/value

The research on the influence of surface roughness on fatigue life can lay the technical foundation for the life prediction of products and have great significance to the quality evaluation of products.

Details

Engineering Computations, vol. 38 no. 6
Type: Research Article
ISSN: 0264-4401

Keywords

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