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1 – 10 of 358Haichao Cui, Qiang Gao, Xiaolan Li and Huajiang Ouyang
This paper aims to propose an efficient and accurate method to analyse the transient heat conduction in a periodic structure with moving heat sources.
Abstract
Purpose
This paper aims to propose an efficient and accurate method to analyse the transient heat conduction in a periodic structure with moving heat sources.
Design/methodology/approach
The moving heat source is modelled as a localised Gaussian distribution in space. Based on the spatial distribution, the physical feature of transient heat conduction and the periodic property of structure, a special feature of temperature responses caused by the moving heat source is illustrated. Then, combined with the superposition principle of linear system, within a small time-step, computation of results corresponding to the whole structure excited by the Gaussian heat source is transformed into that of some small-scale structures. Lastly, the precise integration method (PIM) is used to solve the temperature responses of each small-scale structure efficiently and accurately.
Findings
Within a reasonable time-step, the heat source applied on a unit cell can only cause the temperature responses of a limited number of adjacent unit cells. According to the above feature and the periodic property of a structure, the contributions caused by the moving heat source for the most of time-steps are repeatable, and the temperature responses of the entire periodic structure can be obtained by some small-scale structures.
Originality/value
A novel numerical method is proposed for analysing moving heat source problems, and the numerical examples demonstrate that the proposed method is much more efficient than the traditional methods, even for larger-scale problems and multiple moving heat source problems.
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Chuanbao Nie, Bowen Fu and Qiang Gao
This paper aims to develop an efficient numerical method for nonlinear transient heat conduction problems with local radiation boundary conditions and nonlinear heat sources.
Abstract
Purpose
This paper aims to develop an efficient numerical method for nonlinear transient heat conduction problems with local radiation boundary conditions and nonlinear heat sources.
Design/methodology/approach
Based on the physical characteristic of the transient heat conduction and the distribution characteristic of the Green’s function, a quasi-superposition principle is presented for the transient heat conduction problems with local nonlinearities. Then, an efficient method is developed, which indicates that the solution of the original nonlinear problem can be derived by solving some nonlinear problems with small structures and a linear problem with the original structure. These problems are independent of each other and can be solved simultaneously by the parallel computing technique.
Findings
Within a small time step, the nonlinear thermal loads can only induce significant temperature responses of the regions near the positions of the nonlinear thermal loads, whereas the temperature responses of the remaining regions are very close to zero. According to the above physical characteristic, the original nonlinear problem can be transformed into some nonlinear problems with small structures and a linear problem with the original structure.
Originality/value
An efficient and accurate numerical method is presented for transient heat conduction problems with local nonlinearities, and some numerical examples demonstrate the high efficiency and accuracy of the proposed method.
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Dong Qiang Gao, Rui Wang and Wei Chen
The effect of the load on the tribological properties of Si3N4-hBN sliding against Si3N4 were investigated under dry and water lubrication condition.
Abstract
Purpose
The effect of the load on the tribological properties of Si3N4-hBN sliding against Si3N4 were investigated under dry and water lubrication condition.
Design/methodology/approach
Using a MMU-5G type pin-on-disc friction and wear tester.
Findings
Under the dry friction, the wear mechanism was dominated by ploughing and abrasive wear, and the contact status was elastic contact under the load less than 25 N. With the increase of the load, the friction coefficient decreased; the main wear mechanism was fatigue fracture, and the contact status turned into plastic contact. Under water lubrication, effective lubrication film could be produced on the worn surface, and it had a function of fluid lubrication under the load less than 15 N. With the increase of the load, the pin and the disc came into direct contact, and the friction and wear of the pairs were aggravated; the wear mechanism changed from chemical wear into abrasive wear and brittle spalling.
Originality/value
The study on the effect of the load on the tribological properties of Si3N4-hBN sliding against Si3N4 was investigated under dry and water lubrication condition in the way of contact stress.
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Dongdong He, Qiang Gao and Wanxie Zhong
The purpose of this paper is to propose an accurate and efficient numerical method for determining the dynamic responses of a tensegrity structure consisting of bars, which can…
Abstract
Purpose
The purpose of this paper is to propose an accurate and efficient numerical method for determining the dynamic responses of a tensegrity structure consisting of bars, which can work under both compression and tension, and cables, which cannot work under compression.
Design/methodology/approach
An accurate time-domain solution is obtained by using the precise integration method when there is no cable slackening or tightening, and the Newton–Raphson scheme is used to determine the time at which the cables tighten or slacken.
Findings
Responses of a tensegrity structure under harmonic excitations are given to demonstrate the efficiency and accuracy of the proposed method. The validation shows that the proposed method has higher accuracy and computational efficiency than the Runge–Kutta method. Because the cables of the tensegrity structure might be tense or slack, its dynamic behaviors will exhibit stable periodicity, multi-periodicity, quasi-periodicity and chaos under different amplitudes and frequencies of excitation.
Originality/value
The steady state response of a tensegrity structure can be obtained efficiently and accurately by the proposed method. Based on bifurcation theory, the Poincaré section and phase space trajectory, multi-periodic vibration, quasi-periodic vibration and chaotic vibration of the tensegrity structures are predicted accurately.
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This chapter explores the development of sport sociology in China from its transition from an ‘imported’ Western concept to a ‘localised’ Chinese discipline. Specifically, this…
Abstract
This chapter explores the development of sport sociology in China from its transition from an ‘imported’ Western concept to a ‘localised’ Chinese discipline. Specifically, this chapter considers the role of the body in this process. This chapter offers some descriptive insight into the development of sport sociology in China, focussing on how it has transitioned from an ‘imported’ Western concept to a ‘localised’ discipline with its own unique characteristics. It also seeks to address some differences and similarities between Eastern and Western ideologies regarding the concept of the ‘body’ and how these differences influence the study of sport sociology in China. The chapter uses a historical and philosophical approach to analyse the development of sport sociology in China. It examines the concept of the body in both Western and Chinese contexts and how these concepts have influenced the development of sport sociology in China. The value of this work is it provides a unique perspective on the development of sport sociology in China, highlighting the role of the body and the process of localization. It contributes to the understanding of the interaction between Western and Eastern ideologies in the field of sport sociology.
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Liang Zhang, Qiang Gao, Yin Liu and Hongwu Zhang
The purpose of this paper is to propose an efficient finite element formulation for nonlinear analysis of clustered tensegrity that consists of classical cables, clustered cables…
Abstract
Purpose
The purpose of this paper is to propose an efficient finite element formulation for nonlinear analysis of clustered tensegrity that consists of classical cables, clustered cables and bars.
Design/methodology/approach
The derivation of the finite element formulation is based on the co-rotational approach, which decomposes a geometrically nonlinear deformation into a large rigid body motion and a small-strain deformation. A tangent stiffness matrix of a clustered cable is proposed and the Newton-Raphson scheme is employed to solve the nonlinear equation.
Findings
The derived tangent stiffness matrix, including an additional stiffness terms that describes the slide effect of pulleys, can regress to the stiffness matrix of a classical cable, which is convenient for the implementation of finite element procedure. Two typical numerical examples show that the proposed formulation is accurate and requires less iteration than the force density method.
Originality/value
The co-rotational formulation of a clustered cable is originally proposed, although some mature methods, such as the TL, Force Density and Dynamic Relaxation method, have been applied to nonlinear analysis of clustered tensegrity. The proposed co-rotational formulation proved efficient.
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This first chapter is the introduction to the book. The purpose of this book is to address and better understand why China tightly embraces modern sport in contemporary times…
Abstract
This first chapter is the introduction to the book. The purpose of this book is to address and better understand why China tightly embraces modern sport in contemporary times. Some view this as an indicator of glocalisation and a result of Western industrial civilization putting pressure on China to showcase their strengths as a nation. Some important considerations to explore are China's mediated ability to play and compete with the west. Sport is also seen as a channel of observing global political and economic challenges, especially those in the current context of the COVID-19 pandemic and the intense tensions between communities, which certainly inspires further academic development. Given China's recently remarkable achievements in sport, it is high time to show the world more inside stories of sport development across the nation. The contributors of this collection bring foundational Chinese context to each chapter as they examine changing sport cultures at different scales.
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Carol Huang and Connie Chuyun Hu
The study examines how the tourism concept developed amongst Chinese students in the United States from 1905 to current juncture. Through the contrasting views presented in two…
Abstract
The study examines how the tourism concept developed amongst Chinese students in the United States from 1905 to current juncture. Through the contrasting views presented in two landmark mega-reviews of Chinese students in the United States and France, the authors concluded that tourism enhances understanding of the host countries resulting in more comprehensive and overall success of Study Abroad Program. After the reopening, China encouraged touring the host country but with extreme financial constraints in the beginning. Tourism of Chinese students became popular and fashionable only in late 1990s with China’s economic prosperity and policy changes to open tourism to foreign countries. As tension with China grew during the COVID pandemic, Chinese students in the United States were used by the Trump Administration as a lever in trade and diplomatic negotiation, and touring became wishful.
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Liemei Yuan, Gang Cai and Jun Gao
The purpose of this paper is to evaluate the effect of antioxidant 2,6-di-tert-butyl-p-methylphenol (BHT) on the thermal stability and fatigue resistance of spirooxazine and then…
Abstract
Purpose
The purpose of this paper is to evaluate the effect of antioxidant 2,6-di-tert-butyl-p-methylphenol (BHT) on the thermal stability and fatigue resistance of spirooxazine and then study the properties of photochromic polyvinyl butyral resin (PVB) films.
Design/methodology/approach
BHT was introduced into the spirooxazine system by blending and covalent bonding. The properties of spirooxazine solutions and photochromic PVB films were studied.
Findings
The thermal stability and fatigue resistance of spirooxazine covalently linked (BHT-SO) or mixed (BHT/SO) with BHT were higher than the system without BHT, and BHT-SO was the better one. But acidic substance would greatly impair the fatigue resistance of spirooxazine. The optimum addition amount of BHT-SO2 to PVB was 2.5 per cent, and the minimum limit was 0.01 per cent. The fading kinetic and fatigue resistance of film were similar to the solution and better. Plasticizer could accelerate the fading rate and strengthen the mechanical properties of photochromic film but had no effect on the fatigue resistance.
Research limitations/implications
Spirooxazine could be grafted onto the PVB chain to make the ring closure fading reaction slower.
Practical implications
In addition to the wide application prospects of photochromic materials in decoration, optical storage, etc., the photochromic PVB film in the car safety glass can absorb sunlight and turn blue, then fade to colorless when the sunlight disappears, making the interior environment more comfortable.
Originality/value
The introduction of BHT into the spirooxazine system not only exerts its ability to capture free radicals, but its bulky volume also increases the resistance of the ring closure, making the fading process slower.
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