Youjie Chen, Rong Fu, Junying Yang, En Zhang, Linlin Su and Fei Gao
This study aims to clarify the relationship between the coefficient of friction (COF) and temperature of aluminum-based brake discs.
Abstract
Purpose
This study aims to clarify the relationship between the coefficient of friction (COF) and temperature of aluminum-based brake discs.
Design/methodology/approach
Three friction blocks with different COFs are examined by a TM-I-type reduced-scale inertial braking dynamometer. On this basis, the thermo-mechanically coupled model of friction pairs is established to study the evolution of brake disc temperature under different COFs using ADINA software.
Findings
Results indicate that the calculated disc temperature field matches the experimental well. The effect of COF on the peak temperature is magnified by the braking speed. With the COF increasing, the rise rate of instantaneous peak temperature is accelerated, and the dynamic equilibrium period and cooling-down period are observed in advance. The increase in COF promotes the area ratio of the high-temperature zone and the maximum radial temperature difference. When the COF is increased from 0.245 to 0.359 and 0.434 at 140 km/h, the area ratio of high-temperature zone increases from 12% to 44% and 49% and the maximum radial temperature difference increases from 56°C to 75°C and 83°C. The sensitiveness of the axial temperature difference to the COF is related to the braking time. The maximum axial temperature difference increases with COF in the early stages of braking, while it is hardly sensitive to the COF in the later stages of braking.
Originality/value
The effect of COF on the aluminum-based brake disc temperature is revealed, providing a theoretical reference for the popularization of aluminum-based brake discs and the selection of matching brake pads.
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Keywords
Youjie Chen, Fei Gao, Rong Fu, Linlin Su, Xiaoming Han and Junying Yang
This study aims to clarify the relationship of friction material type and brake disc temperature through braking experiment.
Abstract
Purpose
This study aims to clarify the relationship of friction material type and brake disc temperature through braking experiment.
Design/methodology/approach
The braking performances of resin materials (RM), semimetallic materials (SM) and copper-based powder metallurgy materials (PM) friction blocks mating with forged steel brake disc were examined based on TM-I-type reduced-scale inertial braking dynamometer. The brake disc surface temperature was recorded by infrared thermal camera during braking.
Findings
Experimental results indicate that the thermal wear resistance of three friction materials differs with mental content, resulting in the deviation of pad-disc system contact state during braking, thus forming different temperature distribution on the brake disc surface. The peak temperature on the disc face of RM (190°C) is 36.6% and 45.4% lower than that of PM (300°C) and SM (348°C) at 160 km/h. The maximum radial temperature deviation of PM (35°C) is approximately three times than that of RM (12°C) and 40% higher than that of SM (25°C) at 50 km/h, whereas the maximum temperature deviation of SM (97°C) is six times than that of RM (16°C) and 31% higher than that of PM (74°C) at 160 km/h.
Originality/value
The effect of friction material type on the disc surface temperature distribution is revealed, which provides a meaningful reference for the design of brake friction pairs and choice of brake pad materials.
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Xiangyu Du, Junying Yang, Fei Gao, Xiaoming Han and Linlin Su
This paper aims to reveal the effects of the copper third body on different copper matrix friction materials with a novel experimental way called “exogenous powder.”
Abstract
Purpose
This paper aims to reveal the effects of the copper third body on different copper matrix friction materials with a novel experimental way called “exogenous powder.”
Design/methodology/approach
An accurate adding device of exogenous copper powder was designed to control the flow rate. The tribological properties with and without exogenous copper powder were investigated by a pin-on-disc tribometer during dry sliding.
Findings
Experimental results indicate that the Cu addition tends to increase the friction coefficient. For pure Cu material, the exogenous copper third body exhibits poor fluidity on the friction surface, causing serious adhesive wear on the friction interface. For the Cu 90% + 10% Gr material, the plasticity of exogenous copper powder may intensify the deformation of the third body of the surface, presenting layered accumulation distribution. For the pure Cu and Cu 95% + 5% SiO2 material, the Cu addition makes the composition and density of the third body uneven in the direction of depth.
Originality/value
The role of the copper component on different materials is revealed from a new perspective, and the relationship between the third body structure and the friction properties is explored.
Details
Keywords
Junying Yu, Jiaxuan Xie and Honglin Lu
As a retail operation mode of emerging mixed reality (MR) technology, virtual fitting room (VFR) revolutionizes how consumers interact with fashion brands.
Abstract
Purpose
As a retail operation mode of emerging mixed reality (MR) technology, virtual fitting room (VFR) revolutionizes how consumers interact with fashion brands.
Design/methodology/approach
The research investigates the impact mechanisms of VFR technology through retail operational performance from the perspective of purchase intention and post-purchase intention. Around 783 valid questionnaires were collected using the questionnaire to analyze, including 327 VFR technology users and 394 VFR technology non-users.
Findings
The results indicate that visual vividness, interactive control and personalized provision of VFR technology positively influence the retail operational performance of fashion brands, except for the online purchase intention. The study further reveals that the influence of VFR technology on retail operational performance is carried by perceived value and technology attitude, with the moderating role of perceived body image.
Originality/value
These findings expand and enrich existing research on VFR technology, providing recommendations and valuable insights into widening the application and continuous improvement of VFR technology.
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Keywords
Gongli Luo, Junying Hao and He Ma
Corporate philanthropy is increasingly a vital decision-making basis for consumers to purchase and establish relationships with enterprises. However, few studies have examined…
Abstract
Purpose
Corporate philanthropy is increasingly a vital decision-making basis for consumers to purchase and establish relationships with enterprises. However, few studies have examined corporate philanthropy from the perspective of community evolution. To address this gap, this study aims to provide a more in-depth and holistic investigation of corporate philanthropy by examining the evolution of social media brand communities caused by corporate philanthropy and the characteristics of consumer interactive behavior.
Design/methodology/approach
Web crawlers developed by Python were employed to collect data of ERKE from Sina Weibo (the Chinese equivalent of Twitter). A total of 2,736 posts and 7,774 comments were collected and investigated using social network and sentiment tendency analyses.
Findings
The results showed that the evolution of the social media brand community presented a prominent three-stage characteristic influenced by corporate philanthropy. The findings not only support the benefits of corporate philanthropy but also show the possible disadvantages. Besides, this study further concluded the characteristics of consumer interactive behavior in the social media brand community.
Originality/value
This paper addresses an attractive and practical issue related to the impact of corporate philanthropy. Moreover, this study is one of the first studies to examine the impact of corporate philanthropy in the context of the social media brand community. The findings of this study will provide a valuable reference for community operations and practitioners of brands.
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Xin Rui, Junying Wu, Jianbin Zhao and Maryam Sadat Khamesinia
Based on the positive features of the shark smell optimization (SSO) algorithm, the purpose of this paper is to propose a method based on this algorithm, dynamic voltage and…
Abstract
Purpose
Based on the positive features of the shark smell optimization (SSO) algorithm, the purpose of this paper is to propose a method based on this algorithm, dynamic voltage and frequency scaling (DVFS) model and fuzzy logic to minimize the energy consumption of integrated circuits of internet of things (IoT) nodes and maximize the load-balancing among them.
Design/methodology/approach
Load balancing is a key problem in any distributed environment such as cloud and IoT. It is useful when a few nodes are overloaded, a few are under-loaded and the remainders are idle without interrupting the functioning. As this problem is known as an NP-hard one and SSO is a powerful meta-hybrid method that inspires shark hunting behavior and their skill to detect and feel the smell of the bait even from far away, in this research, this study have provided a new method to solve this problem using the SSO algorithm. Also, the study have synthesized the fuzzy logic to counterbalance the load distribution. Furthermore, DVFS, as a powerful energy management method, is used to reduce the energy consumption of integrated circuits of IoT nodes such as processor and circuit bus by reducing the frequency.
Findings
The outcomes of the simulation have indicated that the proposed method has outperformed the hybrid ant colony optimization – particle swarm optimization and PSO regarding energy consumption. Similarly, it has enhanced the load balance better than the moth flame optimization approach and task execution node assignment algorithm.
Research limitations/implications
There are many aspects and features of IoT load-balancing that are beyond the scope of this paper. Also, given that the environment was considered static, future research can be in a dynamic environment.
Practical implications
The introduced method is useful for improving the performance of IoT-based applications. We can use these systems to jointly and collaboratively check, handle and control the networks in real-time. Also, the platform can be applied to monitor and control various IoT applications in manufacturing environments such as transportation systems, automated work cells, storage systems and logistics.
Originality/value
This study have proposed a novel load balancing technique for decreasing energy consumption using the SSO algorithm and fuzzy logic.
Details
Keywords
Abstract
Purpose
A high-precision gyroscope is an important tool for accurate positioning, and the amplitude stability and frequency tracking ability of the drive control system are important and necessary conditions to ensure the precision of micro-electro-mechanical systems (MEMS) gyroscopes. To improve the precision of MEMS gyroscopes, this paper proposes a method to improve the amplitude stability and frequency tracking ability of a drive control system.
Design/methodology/approach
A frequency tracking loop and an amplitude control loop are proposed to improve the frequency tracking ability and amplitude stability of the drive control system for a MEMS gyroscopes. The frequency tracking loop mainly includes a phase detector, a frequency detector and a loop filter. And, the amplitude control loop mainly includes an amplitude detector, a low-pass filter and an amplitude control module. The simulation studies on the frequency tracking loop, amplitude control loop and drive control system composed of these two loops are implemented. The corresponding digital drive control algorithm is realized by the Verilog hardware description language, which is downloaded to the application-specific integrated circuits (ASIC) platform to verify the performances of the proposed method.
Findings
The simulation experiments in Matlab/Simulink and tests on the ASIC platform verify that the designed drive control system can keep the amplitude stable and track the driving frequency in real time with high precision.
Originality/value
This study shows a way to design and realize a drive control system for MEMS gyroscopes to improve their tracking ability. It is helpful for improving the precision of MEMS gyroscopes.
Details
Keywords
Junying Liu, Ying Wang and Xueyao Du
Foreign construction subsidiaries play an important role in the global construction market. How to establish and maintain long-term sustainable performance has attracted increased…
Abstract
Purpose
Foreign construction subsidiaries play an important role in the global construction market. How to establish and maintain long-term sustainable performance has attracted increased attention, but only a few studies have considered this issue. The purpose of this study is to explore the relationship between autonomy and the sustainable performance of subsidiaries and to provide support for their management control modes.
Design/methodology/approach
From an institutional logics perspective, empirical research using a questionnaire survey was conducted following the methodological framework of this study. Relevant data were collected from 106 experienced managers of foreign construction subsidiaries, and the hypotheses were tested through a regression model.
Findings
The results show that foreign construction subsidiaries have a high degree of operational autonomy, which tends to strengthen their embeddedness in the host country and improve their sustainable performance. However, the role of strategic autonomy is not found to be significant. The moderation results show that the positive impact between operational autonomy and external network embeddedness is strengthened by institutional distance. Institutional distance has no significant moderating impact on the relationship between strategic autonomy and external network embeddedness, respectively.
Research limitations/implications
Geographical limitations may exist as the survey is focused on the Chinese construction foreign subsidiaries. However, based on an institutional logics perspective, this study discusses the management control mode of foreign subsidiaries, which enriches the antecedents of sustainable performance and can provide an in-depth explanation of the effects of the organizational strategies of multinational construction enterprises.
Practical implications
This study provides beneficial information for the sustainable performance of foreign construction subsidiaries. It will provide detailed guidance to managers located in different institutional environments on optimally promoting the sustainable development of subsidiaries.
Originality/value
This study identifies autonomy as an important antecedent, making it one of the first studies investigating autonomy on the sustainable performance of foreign construction subsidiaries. The findings of this study can contribute to the construction subsidiaries' sustainable performance literature and provide novel, comprehensive knowledge for academia and practice.
Details
Keywords
Juni Ahyar and Rasyimah
Purpose – This study aims to describe the planning of learning, learning organizing implementation, and evaluating the learning of Bahasa in a high school in Lhokseumawe…
Abstract
Purpose – This study aims to describe the planning of learning, learning organizing implementation, and evaluating the learning of Bahasa in a high school in Lhokseumawe.
Methodology – The research method was descriptive analysis with a qualitative approach. Data collection used the techniques of observation, interview, and literature review. The subjects of research were the principal, vice principal, Chairman of Department, and Bahasa teachers in the high school. The data obtained were analyzed with the technique of reduction, display, and verification.
Findings – The results showed that the lessons plan in the high school have been compiled by the Indonesian language/Bahasa teachers, including analyzing subjects, drawing up the annual and semester programs, and syllabus. All the planning of learning Bahasa have been well structured and documented. The implementation of the orientation direction or Bahasa Learning is adapted to the needs and level of education. The implementation of study conducted showed the positive things in accordance with the school-based curriculum.
Research Limitations/Implications – Organizing learning Bahasa also showed the positive things based on the management system. Bahasa teachers carried out their roles and their responsibilities based on their job description. This condition has brought positive influence on the quality of learning Bahasa which shows an increase from year to year.
Practical Implications – Activities and aspects of the Bahasa learning adapted to the assessment are based on the syllabus and compiled lesson plan. The evaluation phase is applied to improve the learning activities. This form of evaluation was done either by oral or writing.
Originality/Value – This is the first research to identify learning management of Bahasa in senior high schools in Lhokseumawe.
Li Feng, Junying Liu, Zhixiu Wang and Yanyan Hong
The regulatory landscape surrounding international construction projects presents significant challenges, and contractors are still struggling to pay a painful price for their…
Abstract
Purpose
The regulatory landscape surrounding international construction projects presents significant challenges, and contractors are still struggling to pay a painful price for their performance in the project. While existing research has identified various causes of contractor compliance, the intricate interplay of these factors and their impact on compliance remain largely elusive. The motivation-opportunity-ability (MOA) framework may hold the key to determining what factors can foster induced contractor compliance in international projects.
Design/methodology/approach
This study collected 124 valid data samples from practitioners involved in large-scale international contracting projects through expert interviews and questionnaire surveys. Fuzzy-set qualitative comparative analysis (fsQCA) was employed to analyze the diverse combinations of contractor compliance factors.
Findings
The study identifies seven key factors that contribute to compliance behavior among international construction contractors: economic motivation, social motivation, normative motivation, legal completeness, deterrent sanctions, organizational learning and compliance management ability. The interplay of these factors promotes compliance in the following ways: When international construction contractors are influenced by both social and normative motivations, they exhibit a higher level of compliance. In situations where regulatory systems are relatively weak, the ability to manage compliance becomes the primary driver of compliance behavior for businesses. A comprehensive legal framework creates a conducive environment for contractors to improve their compliance through organizational learning.
Research limitations/implications
The findings offer guidance for international construction contractors in enhancing compliance by considering factors such as motivations, legal frameworks, organizational learning and compliance management. This can lead to improved risk management and performance in international projects.
Social implications
This research enhances fair and ethical practices in international construction by identifying compliance drivers, fostering positive social impact, mitigating negative consequences and empowering local communities. It informs legal and regulatory reform, encourages improved business practices and contributes to knowledge advancement in the field. Overall, the findings have the potential to positively impact the social fabric of international construction projects.
Originality/value
This study has made an important contribution to the field of compliance theory by integrating theories from multiple disciplinary domains and constructing a new theoretical framework from the perspectives of motivation, opportunity and capability. By elucidating how these factors interact and influence compliance behavior among international construction contractors, this research aids in understanding the complex dynamics of contractor compliance behavior and provides theoretical reference for compliance governance within the construction industry.