Search results

1 – 7 of 7
Per page
102050
Citations:
Loading...
Access Restricted. View access options
Article
Publication date: 8 March 2011

Jian‐Qiang Hu, Xin‐Lin Wang, Ge‐Lin Dai, Yi‐Wei Fei, Xian‐Yong Wei and Zhi‐Min Zong

Molybdenum dithiocarbamate (MoDDC) has good antiwear and friction‐reducing properties in lubricants, and can be protected against thermo‐oxidative degradation. However…

390

Abstract

Purpose

Molybdenum dithiocarbamate (MoDDC) has good antiwear and friction‐reducing properties in lubricants, and can be protected against thermo‐oxidative degradation. However, MoDDC‐containing lubricants may lose their ability to reduce friction over time, which may result from its concentration in oils below a critical concentration owing to oxidative degradation of MoDDC. Thus, in order to enhance the durability of the low friction performance of MoDDC, the paper aims to investigate good synergistic antioxidants with MoDDC.

Design/methodology/approach

The antioxidation properties of molybdenum dialkyldithiocarbamate (M 807) – and p,p‐dioctyldiphenylalmine (V 81) – or mixed octylated and butylated diphenylalmines (V 961)‐containing poly‐α‐olefin (PAO)‐derived lubricants were evaluated by differential scanning calorimetry (DSC) and modified penn state micro‐oxidation test (PMOT). DSC test measures incipient oxidation temperature (OT) and oxidation induction time (IT) of the lubricant at high temperatures and the oxidation stability of oil weight loss is measured by PMOT. Moreover, the oxidized samples were analyzed by Fourier transform infrared (FTIR) and electron spin resonance (ESR).

Findings

A DSC test shows that OT and IT of V 81‐ or V 961‐containing PAO were improved significantly by M 807 addition. A PMOT indicates that when combining with V 81 antioxidants, M 807 can also effectively reduce the increase in weight loss of PAO and deposits formed in oils. These results suggest that the M 807 shows a good antioxidative synergism with alkylated diphenylamine antioxidants. In addition, FTIR results from a PMOT confirm that the addition of M 807 can significantly enhance the oxidation IT of oils containing V 81 and inhibit formation of oxidation products including carbonyl bonds or hydroxyl group. ESR analysis from a PMOT indicates that M 807 may form stable radicals with arylamine by the coordination effect.

Originality/value

This paper provides simple and quick methods to evaluate synergistic antioxidation properties between different types of additives, and a mechanism of the inhibition involving a synergy was proposed. They can offer practical help in industrial applications and to an individual starting out on an academic career.

Details

Industrial Lubrication and Tribology, vol. 63 no. 2
Type: Research Article
ISSN: 0036-8792

Keywords

Access Restricted. View access options
Article
Publication date: 1 November 2006

Jian‐Qiang Hu, Xian‐Yong Wei and Zhi‐Min Zong

Pure 2,5‐dimercapto‐1,3,4‐thiadiazole (DMTD) disulfide dimer (DMS2) shows excellent four ball weld properties, however, the product is a solid material with relatively low initial…

625

Abstract

Purpose

Pure 2,5‐dimercapto‐1,3,4‐thiadiazole (DMTD) disulfide dimer (DMS2) shows excellent four ball weld properties, however, the product is a solid material with relatively low initial seizure load and exhibits certain corrosion, which accelerate oxidation of the lubricant by catalytic effect on metals. The author make efforts to resolve problems said by design a novel thiadiazole complex.

Design/methodology/approach

The complex of thiadiazole dimmer and polyglycol (DMS2‐GL) was synthesized as ashless grease additive. The antiwear and load carrying properties of the additive and their synergistic effects was evaluated by four ball tester in four types of lubricant grease. Moreover, corrosion inhibiting properties of compositions said was investigated by copper corrosion test.

Findings

The additive DMS2‐GL possessed good load carrying capacity, and exhibits good synergistic antiwear and load carrying prop with rust inhibitor. In addition, dates obtained from copper corrosion test show that it does not corrode copper but coats the metal with a film, and could improve the anticorrosion of corrosive additives molybdenum dialkyldithiophosphate (MoDDP) and molybdenum dibutyldithiocarbamate (MoDTC) by forming protective films on rubbing surface, which contribute to improving corrosion inhibiting property of greases. Finally, the tribo‐chemical mechanism was proposed that thiadiazole dimer and polyglycol could coordinate with each other by polydentate surface interaction, which means thiadiazole rings interact with the metal surface, polyglycol affords a bridging technology linked thiadiazole dimmers so as to lighten loads and strengthen forces between thiadiazole dimmer moleculars.

Originality/value

This paper provides a good ashless additive which has good antiwear, extreme pressure and corrosion inhibiting properties, and fulfils an identified resources need, which can offer practical help in industrial applications and to an individual starting out on an academic career.

Details

Industrial Lubrication and Tribology, vol. 58 no. 6
Type: Research Article
ISSN: 0036-8792

Keywords

Access Restricted. View access options
Article
Publication date: 23 August 2022

Ru-xin Nie, Kwai-sang Chin, Zhang-peng Tian, Jian-qiang Wang and Hong-yu Zhang

The purpose of this paper is exploring the effects of segment dynamic and temporal dynamic triggered by the COVID-19 pandemic on classifying service quality attributes, thereby…

736

Abstract

Purpose

The purpose of this paper is exploring the effects of segment dynamic and temporal dynamic triggered by the COVID-19 pandemic on classifying service quality attributes, thereby formulating improvement strategies to satisfy customers and respond to threats.

Design/methodology/approach

Given the dynamics of the attractive quality theory, this paper designs a framework with four phases by embedding techniques of text mining and deep learning based on evidence from online reviews.

Findings

This paper figures out dynamics of service quality attributes for distinct segments and their dynamic proportion along with different stages of the pandemic. Another finding demonstrates segment dynamic and temporal dynamic effects of sentiments toward service quality attributes on customer satisfaction under the impacts of pandemic. Classification results and improvement strategies are derived for varying segments at different pandemic situations.

Practical implications

This paper reveals dynamic effects on classifying service quality attributes, which contributes to assisting hospitality practitioners from different segments in improving service quality when facing with the challenges of crisis and potential risks.

Originality/value

Given hospitality industry is time- and segment-sensitive, the authors achieve the quantification of dynamics of attractive quality theory and extend it into hospitality marketing and crisis management from the perspective of dynamics with evidence from online reviews.

Details

International Journal of Contemporary Hospitality Management, vol. 35 no. 1
Type: Research Article
ISSN: 0959-6119

Keywords

Access Restricted. View access options
Book part
Publication date: 3 December 2024

Lei Jian Qiang, Oo Yu Hock and Osaro Aigbogun

The COVID-19 pandemic has influenced entrepreneurial behaviour, including creative industries that have been negatively impacted due to the loss of patrons constrained by movement…

Abstract

The COVID-19 pandemic has influenced entrepreneurial behaviour, including creative industries that have been negatively impacted due to the loss of patrons constrained by movement restrictions. This crisis has led to the failure of many small and medium-sized enterprises (SMEs) and an increase in unemployment. These challenges led to the rapid development of e-commerce and created new business models and firms, which has promoted the development of the economy. Increased marketing channels have become an emergent trend. Facing this challenge, talent development is the most critical factor for scientific and technological innovation, and innovation-driven entrepreneurship is essential in building such talent. The cultivation of innovative talents has become a critical mission of Chinese national education policies. This study analyses the effects of entrepreneurship education (EE) on innovative talent training models using a mixed-method methodology. The study identifies two dimensions of EE, namely institutional environment (IE) and supporting infrastructure (SI), having a significant direct effect on student’s innovation capability. The results highlighted learning institutions should combine innovation-driven entrepreneurial ecosystem cultivation with EE programmes, while strengthening support of IE and infrastructure that enhances the student’s innovation practice ability with both human and social capital. Furthermore, practice-oriented innovative EE should be encouraged to enhance innovation capability in the new economic environment.

Details

Creative (and Cultural) Industry Entrepreneurship in the 21st Century: Policy Challenges for and by Policymakers
Type: Book
ISBN: 978-1-80455-907-9

Keywords

Available. Content available
Article
Publication date: 8 June 2012

620

Abstract

Details

Chinese Management Studies, vol. 6 no. 2
Type: Research Article
ISSN: 1750-614X

Access Restricted. View access options
Article
Publication date: 29 July 2014

Xiaohua Yang, Chongli Di, Ying Mei, Yu-Qi Li and Jian-Qiang Li

The purpose of this paper is to reduce the computational burden and improve the precision of the parameter optimization in the convection-diffusion equation, a new algorithm, the…

92

Abstract

Purpose

The purpose of this paper is to reduce the computational burden and improve the precision of the parameter optimization in the convection-diffusion equation, a new algorithm, the refined gray-encoded evolution algorithm (RGEA), is proposed.

Design/methodology/approach

In the new algorithm, the differential evolution algorithm (DEA) is introduced to refine the solutions and to improve the search efficiency in the evolution process; the rapid cycle operation is also introduced to accelerate the convergence rate. The authors apply this algorithm to parameter optimization in convection-diffusion equations.

Findings

Two cases for parameter optimization in convection-diffusion equations are studied by using the new algorithm. The results indicate that the sum of absolute errors by the RGEA decreases from 74.14 to 99.29 percent and from 99.32 to 99.98 percent, respectively, compared to those by the gray-encoded genetic algorithm (GGA) and the DEA. And the RGEA has a faster convergent speed than does the GGA or DEA.

Research limitations/implications

A more complete convergence analysis of the method is under investigation. The authors will also explore the possibility of adapting the method to identify the initial condition and boundary condition in high-dimension convection-diffusion equations.

Practical implications

This paper will have an important impact on the applications of the parameter optimization in the field of environmental flow analysis.

Social implications

This paper will have an important significance for a sustainable social development.

Originality/value

The authors establish a new RGEA algorithm for parameter optimization in solving convection-diffusion equations. The application results make a valuable contribution to the parameter optimization in the field of environmental flow analysis.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 24 no. 6
Type: Research Article
ISSN: 0961-5539

Keywords

Access Restricted. View access options
Article
Publication date: 17 September 2019

Qiang Jian

This paper aims to study the effects of digital flipped classroom teaching method integrated cooperative learning model on learning motivation and outcome. From the perspective of…

2170

Abstract

Purpose

This paper aims to study the effects of digital flipped classroom teaching method integrated cooperative learning model on learning motivation and outcome. From the perspective of promoting students’ learning engagement, this study puts forward suggestions for the effective implementation of flipped classroom teaching, so as to provide reference for the implementation of flipped classroom teaching practice in colleges and universities. Along with the time change and promotion of 12-year compulsory education, traditional didactic instruction can no longer satisfy all students. The reform wave in education is therefore emerged in past years, where the “flipped classroom” model strikes a chord and becomes a trend.

Design/methodology/approach

By applying nonequivalent pretest posttest control group design to the experimental research, 242 college students in Henan Province are selected as subjects of study. They are divided into four groups. The first group adopts the flip classroom teaching method. The second group adopts the cooperative teaching method. The third group adopts the flipping classroom teaching method integrated the cooperative teaching method. The fourth group (control group) adopts the traditional teaching method. The study lasted 15 weeks with sessions carried out 3 h a week.

Findings

The research results show significant effects of flipped classroom teaching method on learning motivation, flipped classroom teaching method on learning outcome, cooperative learning on learning motivation, cooperative learning on learning outcome, flipped classroom teaching method integrated cooperative learning on the promotion of learning motivation and flipped classroom teaching method integrated cooperative learning on the promotion of learning outcome.

Research limitations/implications

First, on the basis of consulting the links of many teaching strategies and summarizing the experience of flipped classroom practice in famous universities, a series of teaching strategies is put forward. However, the pertinence of different subjects may be different, which requires teachers to focus on the specific practice of reference. Second, due to the limitation of time, the author spent more time and energy on the proposal part of strategy, and the scientific nature of the strategy is not verified in practice, so it needs to spend time and practice in the later stage to improve this work.

Practical implications

This topic is the integrated design practice and research of flipped classroom in current teaching. The practical significance of the research is to find a solution to the problem of low learning efficiency of students in traditional classrooms, so as to update teachers’ teaching concepts, change teaching methods and promote teaching behaviors. In flipped classroom, there is a systematic integrated design process before, during and after class, which can effectively improve teachers’ teaching design ability, help students change their learning methods and truly improve students’ learning efficiency and effectiveness. The research on the implementation of flipped classroom can enrich the theory of flipped classroom, including the research on the orientation of learning theory and the reorientation of the role of teachers and students. This study can provide theoretical support for the strategies and environment for the cultivation of students’ independent learning ability. The results of this study can provide a reference for improving the scientificity and diversity of research methods.

Originality/value

Based on the integrated design of flipped classroom before, during and after class, this research systematically explores the role of flipped classroom in cultivating students’ autonomous learning ability in the teaching of information science and technology, and studies how to maximize the role of flipped classroom in teaching to promote and help students’ learning. In addition, a special iterative method is adopted. In each round of research, according to the opinions of students and peers, the inadequacies and improvements in the last round of research is found, certain links are increased or decreased, and finally the research goals are achieved.

Details

The Electronic Library, vol. 37 no. 5
Type: Research Article
ISSN: 0264-0473

Keywords

1 – 7 of 7
Per page
102050