Abstract
Purpose
This paper aims to present a method to measure the rolling friction coefficient in an easy and fast way. The aim is also to measure the rolling friction coefficient between a small steel ball and a cylindrical aluminum surface.
Design/methodology/approach
An analytical model of the tribosystem of a freely rolling ball and a cylindrical surface is established. The rolling friction coefficient is evaluated from images recorded by a high-speed camera. The coefficient between a 1.58-mm diameter steel ball and a cylindrical aluminum surface is measured. A background subtraction algorithm is used to determine the position of the small steel ball.
Findings
The angular positions of the ball are predicted using the analytical model, and a good agreement is found between the experimental and theoretical results.
Originality/value
An optical method for evaluating the rolling friction coefficient is presented, and the value of this coefficient between a small steel ball and a cylindrical aluminum surface is evaluated.
Details
Keywords
Zhixiong Chen, Weishan Long, Li Song and Xinglin Li
This paper aims to research the tribological and dynamic characteristics of aeroengine hybrid ceramic bearings through wear experiments and simulation analysis.
Abstract
Purpose
This paper aims to research the tribological and dynamic characteristics of aeroengine hybrid ceramic bearings through wear experiments and simulation analysis.
Design/methodology/approach
First, the authors carried out wear experiments on Si3N4–GCr15 and GCr15–GCr15 friction pairs through the ball-disc wear test rig to explore the tribological properties of their materials. Second, using ANSYS/LS-DYNA simulation software, the dynamic simulation analysis of hybrid bearings was carried out under certain working conditions, and the dynamic contact stress of all-steel bearings of the same size was simulated and compared. Finally, the change of the maximum contact stress of the main bearing under the change of load and rotation speed was studied.
Findings
The results show that the Si3N4–GCr15 pair has better tribological performance. At the same time, under the conditions of high speed and heavy load, the simulation analysis shows that the contact stress between the ceramic ball and the raceway of the ring is smaller than the steel ball. That is, hybrid bearings have better transient mechanical properties than all-steel bearings. With the speed increasing to 12,000 r/min, the maximum stress point will shift in the inner and outer rings.
Originality/value
In this study, the tribological and transient mechanical properties of Si3N4 material were comprehensively analyzed through wear experiments and dynamic simulation analysis, which provided a reference for the design of hybrid bearings for next-generation aeroengines.
Details
Keywords
Xiaoguang Wang, Yijun Gao and Zhuoyao Lu
Microblogs are communication platforms for companies and consumers that challenge companies' brand marketing strategies. This paper provides a theoretical basis for expanding…
Abstract
Purpose
Microblogs are communication platforms for companies and consumers that challenge companies' brand marketing strategies. This paper provides a theoretical basis for expanding microblog applications and a practical basis for improving the effectiveness of brand marketing.
Design/methodology/approach
The authors use factor analysis to extract the factors of microblog user influence and construct a structural equation model to reveal the interaction mechanism of the influencing factors. Additionally, the authors clarify the promotion and enhancement effects of these factors.
Findings
Microblog user influence can be converted into richness, interaction and value factors. The richness factor significantly affects the latter two, whereas the interaction factor does not affect the value factor.
Research limitations/implications
First, the sample used is limited to media industry practitioners. To increase generalizability, diverse groups should be included in future studies. Second, this model's theoretical explanatory ability can be further developed by adding other meaningful factors beyond the existing ones.
Originality/value
This study analyzes the factors of microblog user influence in China and validates the relevant elements. As a result, it improves the influence research on social media users and benefits the practice of information recommendation and microblog marketing.
Details
Keywords
Daifeng Zhang, Haibin Duan and Yijun Yang
The purpose of this paper is to propose a control approach for small unmanned helicopters, and a novel swarm intelligence algorithm is used to optimize the parameters of the…
Abstract
Purpose
The purpose of this paper is to propose a control approach for small unmanned helicopters, and a novel swarm intelligence algorithm is used to optimize the parameters of the proposed controller.
Design/methodology/approach
Small unmanned helicopters have many advantages over other unmanned aerial vehicles. However, the manual operation process is difficult because the model is always instable and coupling. In this paper, a novel optimized active disturbance rejection control (ADRC) approach is presented for small unmanned helicopters. First, a linear attitude model is built in hovering condition according to small perturbation linearization. To realize decoupling, this model is divided into two parts, and each part is equipped with an ADRC controller. Finally, a novel Levy flight-based pigeon-inspired optimization (LFPIO) algorithm is developed to find the optimal ADRC parameters and enhance the performance of controller.
Findings
This paper applies ADRC method to the attitude control of small unmanned helicopters so that it can be implemented in practical flight under complex environments. Besides, a novel LFPIO algorithm is proposed to optimize the parameters of ADRC and is proved to be more efficient than other homogenous methods.
Research limitations/implications
The model of proposed controller is built in the hovering action, whereas it cannot be used in other flight modes.
Practical implications
The optimized ADRC method can be implemented in actual flight, and the proposed LFPIO algorithm can be developed in other practical optimization problems.
Originality/value
ADRC method can enhance the response and robustness of unmanned helicopters which make it valuable in actual environments. The proposed LFPIO algorithm is proved to be an effective swarm intelligence optimizer, and it is convenient and valuable to apply it in other optimized systems.
Details
Keywords
Ting Ren, Nan Liu, Hongyan Yang, Youzhi Xiao and Yijun Hu
The purpose of this paper is to examine the relationship between working capital management (WCM) and firm performance in the context of the Chinese economy. Specifically, it…
Abstract
Purpose
The purpose of this paper is to examine the relationship between working capital management (WCM) and firm performance in the context of the Chinese economy. Specifically, it investigates the effects of ownership structures as an internal factor and of institutional environments (IE) as an external factor shaping this relationship.
Design/methodology/approach
The study applies two-way fixed effect regression models to a sample of Chinese listed manufacturing firms for the period of 2010 to 2017. WCM is measured by cash conversion cycles (CCC); profitability is measured by core profit ratios; ownership structures are classified based on state-owned enterprises (SOEs) and non-SOEs; and IEs are measured from dimensions of factor markets (FM) and legal systems (LS).
Findings
First, the results show a negative relationship between CCC and firm performance. Second, the negative relationship between CCC and profitability is significant for non-SOEs but not for SOEs. Third, both the FM and LS strengthen the negative association between CCC and profitability. Fourth, the moderating effect of FMs and LSs is evident for non-SOEs only. The results hold when using alternative measures of WCM and profitability and while controlling for additional variables.
Originality/value
The current study shows that while WCM has a significant effect on the profitability of Chinese firms, such an effect greatly depends on the ownership structures and IE involved. The results thus offer important implications in helping the Chinese government create better IEs and in allowing manufacturing firms to improve upon their WCM practices.
Details
Keywords
Wujian Ye, Hao Huang, Boning Zhang, Yijun Liu and Ziqi Lin
Most existing methods for concrete crack detection are based on deep learning techniques such as convolutional neural networks. However, these models, due to their large memory…
Abstract
Purpose
Most existing methods for concrete crack detection are based on deep learning techniques such as convolutional neural networks. However, these models, due to their large memory footprint, high power consumption and insufficient feature extraction capabilities, face challenges in mobile applications. To address these issues, this paper proposes a lightweight spiking neural network detection model.
Design/methodology/approach
This model achieves fast and accurate crack detection. Firstly, the Gabor-Spiking (GS) module preprocesses input images, extracting texture features and edge features of crack images through Gabor filter convolution modules and spiking convolution modules, respectively. Next, the multiscale residual (MR) module is designed, composed of convolutional layers and residual modules of various scales, to process the fused features and perform crack detection.
Findings
Experimental results demonstrate that the model’s size can be reduced to 4.6 MB, achieving accuracy improvements to 87.3 and 96.4% on the SDNET and OCD datasets, respectively.
Originality/value
This paper proposes a lightweight spiking neural network detection model based on the GS module for edge texture feature fusion and the MR module for crack detection.
Details
Keywords
Philip Davies, Yipeng Liu, Maggie Cooper and Yijun Xing
Recent research has recognised the importance of supply chains and ecosystems as key drivers of successful servitization strategies, especially in the context of…
Abstract
Purpose
Recent research has recognised the importance of supply chains and ecosystems as key drivers of successful servitization strategies, especially in the context of inter-organisational relations (IOR). The body of knowledge has, however, become increasingly fragmented and diverse due to different disciplinary roots of both servitization and IOR research. The purpose of this paper is to take stock of current knowledge and to generate a set of future research directions for servitization-related supply chain and ecosystem research.
Design/methodology/approach
A systematic review methodology was applied. A thematic analysis was conducted on a sample of 34 papers in the period 2010–2021 to identify the key themes within the servitization-related supply chain and ecosystem literature.
Findings
The review revealed a limited, but expanding, knowledge base for servitization-related supply chain and ecosystem research. The findings provide insight into current trends across four thematic areas: theoretical orientation, methodological approaches, research context and research content. Within these themes, it was found that four main areas of research content have been studied (supplier relationships, risk perception and uncertainty, capability development and resource integration), with most research adopting case-based methodologies within three main industrial contexts: manufacturing, industrial and software. Finally, a broad range of theoretical orientations have led to an increasingly fragmented and diverse literature base.
Originality/value
This study is the first to review servitization-related supply chains and ecosystems. It contributes insights through an IOR lens to categorise and organise a core set of themes and concepts for servitization-related supply chain and ecosystems research. It identifies research gaps within the extant literature and presents a set of future research directions.
Details
Keywords
Yipeng Liu, Christina Öberg, Shlomo Yedidia Tarba and Yijun Xing
The purpose of this paper is to focus on emerging market companies that internationalize into advanced economies by means of acquisitions and to investigate brand management…
Abstract
Purpose
The purpose of this paper is to focus on emerging market companies that internationalize into advanced economies by means of acquisitions and to investigate brand management during post-acquisition integration from a multi-level perspective and to identify how a brand management strategy can be constructed. It takes into account the influences of country-of-origin image, corporate brand and brand portfolio to obtain a granular view of post-acquisition brand management.
Design/methodology/approach
A multiple case study approach was adopted. By using case studies and storytelling qualitative research methods, the empirical setting was related to the acquisitions undertaken by Chinese companies in Germany.
Findings
The authors identified three mechanisms for brand management in the post-acquisition integration of emerging market companies – namely, transferring, dynamically redeploying and categorizing – that underpin the interconnection and combined influence of country-of-origin image at the national level, corporate brand at the organizational level and brand portfolio at the product level.
Practical implications
Brand has been viewed as a strategic asset in Chinese cross-border mergers and acquisitions (M&As). Brand management is a dynamic process that involves learning and interaction between the acquirer and target. The research offers a practical guideline for both acquirers and targets in managing brand in the context of acquisitions undertaken by emerging market companies in advanced economies.
Originality/value
The findings provide important insights into the brand management strategies adopted in Chinese cross-border M&As in particular, and emerging market companies venturing into advanced economies in general. The interlinking of country, company and product levels introduces new ideas to the brand literature related to acquisitions, and the setting of Chinese companies acquiring German ones constitutes an important contribution to the understanding of the different ways in which companies from emerging economies may pursue branding strategies in the context of cross-border M&As.
Details
Keywords
Yipeng Liu, Yijun Xing and Mark Starik
Purpose – As a well-recognized qualitative research method, storytelling can help to explain the multilevel and dynamic perspectives in management studies. The authors…
Abstract
Purpose – As a well-recognized qualitative research method, storytelling can help to explain the multilevel and dynamic perspectives in management studies. The authors purposefully chose sustainability stories in the Western context, leadership stories in the Eastern context, and entrepreneurship stories in the West-meets-East context to highlight the benefits of using storytelling in conducting strategy and management research.
Design/Method/Approach – Qualitative research, field research, and comparative analysis.
Findings – Looking through cultural and philosophical lenses, the authors argue that scholars need to pay attention to research contexts when applying storytelling in their fieldwork. Storytelling can help to unpack the contextual factors, especially to disclose dynamics and complexity issues of strategic management phenomena.
Research implications – While storytelling has been widely used in the Western management context, the authors believe we are among the first to suggest that storytelling can become an insightful and fruitful research method in Eastern management and in combined cultural contexts, and hence, they are attempting to potentially help to advance theory development.
Originality/Value – Two applicable conditions for storytelling are discussed, namely, the multilevel/systems perspective and the dynamic perspective, which are illustrated by sustainability, leadership, and entrepreneurship research in both Western and Eastern contexts.
Details
Keywords
Yijie Zhang, Ziyi Guo, Jiangang Wei and Yijun Li
The aim of this paper is to achieve a reasonable microclimate between clothing and the human body and optimize the custom dress pattern.
Abstract
Purpose
The aim of this paper is to achieve a reasonable microclimate between clothing and the human body and optimize the custom dress pattern.
Design/methodology/approach
An interactive design method of 3D modeling, virtual try-on and heat transfer simulation are used. First, a 3D dress is designed with nonuniform rational B-splines curves and tried on virtually. After that, the heat transfer in the body-air-clothing microclimate and temperature distributions on the clothing surface are obtained. Based on the heat transfer in the body-air-clothing system, we design a method to improve the thermal comfort by optimizing the garment pattern digitally. Then, this paper utilized two heat transfer validating indexes to quantify the improvement of thermal comfort, and evaluate the modified model of dress.
Findings
The microclimate under the clothing is varied with the air gap distance, and the heat transfer on the area of the clavicle, bust point and front abandon are higher than other parts due to the narrow air gaps. In view of thermal comfort, the pattern optimization changes the distance ease and reforms the air circulating efficiency. The mean heat transfer and its standard variance are changing by about 10% and more than 20%. Thus, the heat transfer evaluation indexes are suitable to represent the heat transfer and thermal comfort in the microclimate system.
Research limitations/implications
It can be concluded that the methodology proposed in this paper has the advantage of interactive design, 3D visualization and local heat transfer simulation. This technology meets the need of personalized customization and well-considered garment and has broad application prospects.
Originality/value
This study demonstrates that modifying the distance ease on body key girths based on heat transfer is a reliable way to improve thermal comfort. This method meets the consumers’ demand of the comfort of body-fit clothing under the condition of daily activities.
Highlights
3D air gap distributions.
Heat transfer varies with air gap distance.
Thermal comfort can be improved by optimizing garment pattern.
3D air gap distributions.
Heat transfer varies with air gap distance.
Thermal comfort can be improved by optimizing garment pattern.