Search results

The friction between brake pair causes an intense temperature rise on interface during braking, which affects the braking performance seriously. Therefore, building an accurate testing method for frictional temperature rise (FTR) is a prerequisite.

Facing braking conditions of automobiles, an experimental system for testing of FTR based on preset thermometry method (PTM) was established. The FTR was collected by the PTM and the variation laws as well as the cause of errors were analyzed by experiments. The deviations between tested and real temperature were corrected based on tribology and heat theories. Finally, an online prediction method for FTR was pointed out.

After correction, the temperature curve accords well with the laws of tribology and thermal theories. The corrected FTR at braking end point is approximately equal to the authentic temperature test by hand thermometer.

This study eliminated the hysteresis phenomenon of temperature rise sequence and lays a foundation for online accurate monitoring and warning of brake friction temperature rise. It has important theoretical and practical value for expanding the monitoring and improvement of brake performance.

This paper aims to analyze the friction heat conduction and entransy of two friction linings in the high‐speed slide accident of a mine friction hoist.

Firstly, the dynamic thermophysical properties were analyzed and their fitting equations were also obtained. Additionally, the dynamic heat partition ratio was obtained according to the dynamic thermophysical properties. Then, a simple method was developed to solve the temperature rise of friction lining. Finally, based on the theoretical model of temperature rise, the entransy of friction lining with respect to T and t were gained.

The error of temperature rise between simulation result and experiment result is less than 7 per cent, which proves that the theoretical model is correct. The entransy decreases with the temperature below 40°C and it increases after 40°C. The entransy of lining K is a little higher than that of lining G within 19 s, but the entransy of lining G is much higher than lining K after 19 s and the entransy difference gets great gradually. It is indicated that the lining K has good heat‐resistant property which is of great benefit to the tribological property of friction lining.

The authors' study provides a fundamental basis for developing a new friction lining with good heat‐resistant property, and it also brings forward a new quantitative method to evaluate the heat‐transfer capability of friction materials.

A simple method was introduced to calculate the temperature rise of friction lining with the consideration of dynamic thermophysical properties and dynamic heat partition ratio. And the entransy of friction lining was obtained to evaluate the heat‐transfer capability of friction linings quantitatively.

In order to improve the braking safety of mine hoisters, this paper aims to focus on the continuous repetitious emergency braking conditions to investigate an abnormal frictional phenomena called “Frictional catastrophe (FC)” and its mechanisms.

The non‐asbestos brake shoe of a mine hoister was selected as frictional material and its paring material is 16Mn steel. The tribological properties of the brake shoe were tested on the pad‐on‐disc friction tester by the simulation of continuous emergency braking conditions. The thermal analysis experiments, the temperature field simulations and the SEM analysis of the brake shoe were accomplished to reveal the mechanisms of the FC.

It was found that the friction coefficient of the brake shoe sometimes falls suddenly during braking. This abnormal frictional phenomena is called “Frictional catastrophe (FC)”. It is considered that the friction heat, which is accumulated rapidly by the braking on the surface of the brake shoe, makes the surface layer material qualitatively change from the solid state to a mixed state composed of gases, liquids and solid. The frictional modality of the braking changes accordingly from dry friction to lubrication with gases and liquids. The sudden lubrication makes the friction coefficient fall suddenly and induces the FC phenomena.

An abnormal tribological phenomena called “Frictional catastrophe (FC)” was found in this paper. The investigations about the behaviors and mechanisms of the FC are considered helpful for improving the braking safety of mine hoisters and other machines.

The purpose of this paper is to find the influence of the initial braking velocity and braking frequency on the tribological performance of the non‐asbestos brake shoe used in mine hoisters during some continuous emergency brakings.

The tribological performance experiments of the WSM‐3 non‐asbestos brake shoe braking on the 16 Mn steel are investigated on the X‐DM friction tester, by simulating continuous emergency brakings of a mine hoister ten times. Three kinds of tribological indexes: friction coefficient, its stability coefficient, and wearing rate are considered to score the tribological performance of the brake shoe.

When the initial braking velocity increases, the mean friction coefficient of the brake shoe decreases at first, then rises, and falls again finally. But when the braking frequency exceeds seven times, the falling process of the friction coefficient at low‐velocity period does not appear again. Second, when the initial braking velocity is no higher than 10 m/s, the mean friction coefficient rises with the braking frequency increasing. But when the velocity exceeds 10 m/s, the mean friction coefficient rises with the braking frequency increasing at first, then falls. Third, when the initial braking velocity is no higher than 12.5 m/s, the friction coefficient of the brake shoe has quite a favorable stability with the coefficient is no bigger than 75 percent. But when the velocity exceeds 12.5 m/s, the stability of the friction coefficient is diminishing obviously. Fourth, the wearing rate of the brake shoe increases quickly, during the process that the velocity rising from 10 to 12.5 m/s, but increases much more slowly after that period.

The paper investigates the tribological performance of the WSM‐3 non‐asbestos brake shoe during some continuous emergency brakings and finds that, when the initial braking velocity is no higher than 12.5 m/s and the braking frequency is no more than seven times, the WSM‐3 non‐asbestos brake shoe has quite a high friction coefficient, a good friction stability, and a low‐wearing rate, which indicate that it is very appropriate for using in the disk brake of mine hoisters in China.

The purpose of this paper is to present and analyze the effect of applied load and sliding velocity on the tribological behaviors of aramid fiber (AF) reinforced PA1010 which can be a potential material for transmission components.

The PA1010 composites with different content of AF are prepared and the tribology experiments are conducted on a block‐on‐ring wear tester under different experiment conditions. The wear mechanism of the composite is examined by means of scanning electron microscopy.

The addition of AF decreased the friction coefficient of PA1010 and increased its wear resistance. For optimal tribological properties 5∼15 wt% AF is preferred, while the wear resistance is best at 15 wt%. The friction coefficient decreased with increasing load and sliding velocity, but it is more sensitive to load. The main wear mechanism is abrasive wear at relatively low load and sliding velocity. With the increasing of load, the adhesive wear occurs in the matrix, meanwhile obvious fibrillation and layer peeling are observed on the fiber. When the sliding velocity increases, thermal adhesion and fiber debonding is the dominant mechanism.

PA1010 is a useful material for the alternative material of transmission components in industry.

PA1010 composite is prepared with a new kind of AF fiber and the tribology experiments have been carried out emphasizing on the variation of experiment conditions. The results could be useful for the material engineers.

Utilizing the capital asset pricing model (CAPM), the purpose is to analyze whether the stock prices of the corporation that owns sport teams fluctuate based on team performance in the Chinese Super League (CSL).

Several CSL teams are publicly owned corporations. As such, the authors look to see if on-field performance impacts the stock price of the firms. Using the news model from previous research, seemingly unrelated regressions are estimated on CSL games from 2014 through 2017.

The results from the main models indicate some evidence of a statistical relationship between on-field team performance and stock price. Furthermore, the findings for individual teams across markets did not hold consistent across different markets. More specifically, the authors found some instances where successful on-field performance led to a decline in stock prices.

The present study further contributes to the growing literature related to on-field performance and stock prices. Unlike previous research, the use of the CSL as the empirical setting provides the opportunity to use multiple stock markets which provides an opportunity to further examine this relationship. Finally, the study contributes broadly to the literature on professional sports ownership structures around the world.

This paper aims to investigate the lubrication regime in spherical pump, especially under different structural parameters and operational conditions.

A ball-on-plane configuration is adopted to represent the contact model between spherical piston and cylinder cover. The governing equations, which include the Reynolds and elasticity equations, are solved and validated by Jin–Dowson model. Both minimum film thickness and lambda ratio (ratio of minimum fluid film thickness to combined surface roughness of the piston and cylinder cover) of the equivalent model are obtained using an established model.

The results indicate that piston diameter and radial clearance are the two main factors affecting the pump lubrication regime. Other related parameters such as rotation speed of the piston, load, viscosity of working medium, material matching and surface roughness of piston and cylinder cover also have different impacts on the lubrication regime of the spherical pump.

These results emphasize the importance of the design and manufacturing parameters on the tribological performance of spherical pumps and these are also helpful in improving the spherical pump lubrication regime and enlarging its life cycle. This is to certify that to the best of the authors’ knowledge, the content of this manuscript is their own work. This manuscript has only been submitted to this journal and never been published elsewhere. The authors certify that the intellectual content of this manuscript is the product of their own work and that all the assistance received in preparing this manuscript and sources has been acknowledged.

The purpose of this paper is to analyze fans’ perceptions of the corporate social responsibility (CSR) activities of a professional football club, specifically whether or not perceived CSR performances are then likely to influence patronage intentions of the fans in relation to the football club.

The paper uses the example of a professional football club in China as a case study for data analysis. Based on a sample of 451 home team fans, analysis was conducted through calculation of descriptive statistics, and exploratory factor analysis. Regression analysis was conducted to determine the impact of perceived CSR performance on fans’ patronage intentions.

The results revealed that factor 3 (“CSR to customer and employee”) and factor 4 (“Community development and youth education”) were significantly predictive of all the three patronage intention variables, i.e. repeat purchase, word-of-mouth and merchandise consumption. In addition, factor 2 (“charity”) would also affect merchandise consumption intention, but have no effect on any other dimensions.

A scale measuring perceived CSR performance in professional football clubs by the fans in the Chinese context has been developed. In addition, the authors have identified that the two main CSR factors that would influence fans’ patronage intentions are: “CSR to the customer and employee” and “community development and youth education.” Thus, if football clubs are to use CSR strategically to leverage spend, then it is these two areas that they should focus on, explicitly in relation to CSR activities. This paper adds value to an area that is currently under-researched in respect of CSR activities in Chinese professional football.

In 2017, the Chinese Super League (CSL), the first professional football division in the People’s Republic of China (PRC), became the highest-spending league in the international players’ transfer market, with a total spending of €377m. Moreover, the government of the PRC is backing the CSL with an ambitious football plan. Therefore, the purpose of this paper is to examine the governance of the CSL by questioning the organisational viability of the league.

In addition to the relevant international literature, this study is based on 14 recent scholarly articles published in Mandarin from 2013 to 2018 to reflect the national academic debate. Moreover, website research on all CSL clubs has been conducted. The institutional analysis follows the integrative change model of Cunningham (2002) complemented by agency and bureaucracy theory.

The CSL still faces substantial governance problems caused by the divergence of goal setting, organisational inefficiencies and compliance issues. The organisational change is notably constrained by internal competitive value commitments and external power dependency.

The institutional findings on the CSL provide a starting point for empirical studies. The approach contributes to the theory of sport governance processes.

The material and insights are informative for decision makers to evaluate the competitiveness of the CSL.

This paper is the first international in-depth analysis of the governance of the CSL using the body of knowledge published in Mandarin.

The purpose of this paper is to examine the effectiveness of the “Made in China, Made with the World” advertisement broadcast on the US television station CNN in 2009 and derives recommendations for China's further efforts in promoting the image of products made in China (PMC).

Through a survey based on the Solomon four‐group design, this study collected primary data from 546 students at an American university in 2010 and used the data to test the effectiveness of the CNN advertisement and identify factors that affect the respondents' perceptions about PMC.

Statistical tests indicate that the TV advertisement did not result in the expected effects and even had some boomerang effects on the perceptions about PMC and China's developments, and regression analysis confirms these conclusions. Also, the TV advertisement received low ratings from the respondents in credibility, trustworthiness, rationality, information, stimulation, and excitability.

As exports continue to play an important role in the Chinese economy and PMC are likely to face more challenges in the global markets, China needs to understand both consumer preferences and product safety regulations in the foreign markets, focus more on quality and safety over low prices, and improve the effectiveness of its promotion efforts on the basis of scientifically sound studies.

While the CNN TV advertisement was China's first TV campaign abroad to enhance the image of PMC, this paper presents one of the first studies for assessing the effectiveness of the advertisement and deriving recommendations for China's further efforts in promoting PMC.