Xinying Lv, Rongguo Wang, Wenbo Liu and Long Jiang
The purpose of this paper is to investigate the effect of thermal‐oxidative aging at 150°C on the mechanical properties of carbon fibre reinforced bismaleimide composites.
Abstract
Purpose
The purpose of this paper is to investigate the effect of thermal‐oxidative aging at 150°C on the mechanical properties of carbon fibre reinforced bismaleimide composites.
Design/methodology/approach
Composites specimens after thermo‐oxidative aging at 150°C for various times (up to 1,000 h) were investigated by scanning electron microscopy (SEM) for fracture morphology, Fourier transform infrared (FTIR) spectroscopy for chemical structures, and flexural strength test and inter‐laminar shear strength (ILSS) test for mechanical properties.
Findings
The results indicated that the mechanical properties of carbon fibre/BMI composites were affected significantly by testing temperature rather than by aging time. SEM results showed that the good adhesion of fibre and matrix resulted in the better mechanical properties. The composites showed lower flexural strength and ILSS at 150°C due to the viscoelastic behaviour of matrix resin. The FTIR spectra confirmed the decomposition of crosslinked maleimide occurred just on the surface of composites during various aging times.
Research limitations/implications
Results indicated that carbon fibre/BMI composites had excellent heat resistance and aging resistance.
Practical implications
Due to their excellent thermal and mechanical properties, the carbon fibre/BMI composites show greater potential for their applications in some extreme fields such as aerospace and machine.
Originality/value
The paper investigates the relationships of the fracture morphologies of composites and chemical structures of matrix resin to the mechanical properties after thermo‐oxidative aging.
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Da Liu, Wenbo Wang and Yinchuan Zhao
Weather affects consumer decision-making. However, academic research on how weather factors affect specific takeaway foods is limited. This paper aims to fill in the gap and…
Abstract
Purpose
Weather affects consumer decision-making. However, academic research on how weather factors affect specific takeaway foods is limited. This paper aims to fill in the gap and therefore to contribute to online marketing and operation.
Design/methodology/approach
Web crawler techniques were first exploited to collect takeaway food ordering data from Meituan, the world’s largest GMV platform. Then statistics models and a time series regression model were selected to study the weather impact on online orders.
Findings
The findings highlight that certain weather factors, such as temperature, air quality and rainfall have clear effects on most category takeaway orders.
Originality/value
Quantitative analysis of weather impacts on the takeaway ordering business will help to guide the online service platforms for marketing promotion and the settled businesses to make reasonable arrangements for inventory and marketing tactics.
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Lin Qi, Wenbo Zhang, Ronglai Sun and Fang Liu
Giant orthogonal grid barrel vault is generated by deleting members in the inessential force transfer path of the two-layer lattice barrel vault. Consisting of members in the…
Abstract
Purpose
Giant orthogonal grid barrel vault is generated by deleting members in the inessential force transfer path of the two-layer lattice barrel vault. Consisting of members in the essential transfer path only, giant orthogonal grid barrel vault is a new type of structure with clear mechanical behavior and efficient material utilization. The paper aims to discuss this issue.
Design/methodology/approach
The geometrical configuration of this structure is analyzed, and the geometrical modeling method is proposed. When necessary parameters are determined, such as the structural span, length, vault rise, longitudinal and lateral giant grid number and section height to top chord length ratio of the lattice member, the structure geometrical model can be generated.
Findings
Numerical models of giant orthogonal grid barrel vaults with different rise–span ratios are built using the member model that can simulate the pre-buckling and post-buckling behavior. So the possible member buckle-straighten process and the plastic hinge form–disappear process of the structure under strong earthquake can be simulated.
Originality/value
Seismic analysis results indicate that when the structure damages under strong earthquake there are a large number of buckling members and few endpoint plastic hinges in the structure. Dynamic damage of giant orthogonal grid barrel vault under strong earthquake is caused by buckling members that weaken the structural bearing capacity.
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Yang Ji, Erhua Zhou and Wenbo Guo
Anchored in the role of a social arbiter, the purpose of this study is to examine whether and how media coverage has an impact on CEO overconfidence and further explore how media…
Abstract
Purpose
Anchored in the role of a social arbiter, the purpose of this study is to examine whether and how media coverage has an impact on CEO overconfidence and further explore how media ownership and Confucianism affect the relationship in the Chinese context.
Design/methodology/approach
Using a sample of 1,492 Chinese listed companies from 2010 to 2015, the study adopts random effects models to empirically analyze the effect of media coverage on CEO overconfidence and the roles of media ownership and Confucianism.
Findings
The paper finds that media coverage is significantly and positively associated with CEO overconfidence, and the positive relationship between media coverage and CEO overconfidence becomes stronger for state-controlled media. What is more, the influence of media coverage on CEO overconfidence is attenuated for those firms located in stronger Confucianism atmosphere. A further analysis reveals that different tenors of media coverage yield asymmetric effects.
Originality/value
The paper provides a new and solid support for the argument that media praise stimulates CEO overconfidence and increases the knowledge about under what conditions CEO overconfidence varies, broadly speaking which fosters the development of upper echelons theory (UET). Meanwhile, the results extend the literature on media effect and information processing. The findings are also beneficial to improve corporate decisions and government regulation on Chinese media systems.
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Wenbo Li, Bin Dan, Xumei Zhang, Yi Liu and Ronghua Sui
With the rapid development of the sharing economy in manufacturing industries, manufacturers and the equipment suppliers frequently share capacity through the third-party…
Abstract
Purpose
With the rapid development of the sharing economy in manufacturing industries, manufacturers and the equipment suppliers frequently share capacity through the third-party platform. This paper aims to study influences of manufacturers sharing capacity on the supplier and to analyze whether the supplier shares capacity as well as its influences.
Design/methodology/approach
This paper deals with conditions that the supplier and manufacturers share capacity through the third-party platform, and the third-party platform competes with the supplier in equipment sales. Considering the heterogeneity of the manufacturer's earning of unit capacity usage and the production efficiency of manufacturer's usage strategies, this paper constructs capacity sharing game models. Then, model equilibrium results under different sharing scenarios are compared.
Findings
The results show that when the production or maintenance cost is high, manufacturers sharing capacity simultaneously benefits the supplier, the third-party platform and manufacturers with high earnings of unit capacity usage. When both the rental efficiency and the production cost are low, or both the rental efficiency and the production cost are high, the supplier simultaneously sells equipment and shares capacity. The supplier only sells equipment in other cases. When both the rental efficiency and the production cost are low, the supplier’s sharing capacity realizes the win-win-win situation for the supplier, the third-party platform and manufacturers with moderate earnings of unit capacity usage.
Originality/value
This paper innovatively examines supplier's selling and sharing decisions considering manufacturers sharing capacity. It extends the research on capacity sharing and is important to supplier's operational decisions.
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Wenbo Qin, Antonio Sánchez Soliño and Vicente Alcaraz Carrillo de Albornoz
Though China is taking many steps to offer affordable houses to the public, the gap between the demand and supply for such affordable houses is still huge. Rapidly growing demand…
Abstract
Though China is taking many steps to offer affordable houses to the public, the gap between the demand and supply for such affordable houses is still huge. Rapidly growing demand for affordable housing has encouraged large Chinese cities, faced with housing imbalance, to invest in developing affordable properties. As a result, the Chinese central government has started to encourage local governments to use Public-Private Partnerships (PPPs) and private capital to supplement the funding deficit. There is also an on-going debate regarding the need to establish prerequisites for institutions to meet in order to achieve effective PPPs. In this paper, we examine what the current institutional environment is in China and how China is meeting these prerequisites for effective PPPs. We also examine the main programs on affordable housing and propose a potential field for using PPPs. We draw the conclusion that PPPs are more favorable for renting-oriented type projects than owning-oriented projects. In this context, the advantages of the PPP model for China's renting-oriented affordable housing programs are would be the provision of private financing, the enhancing efficiency by involving private sector experts and the statement of bundling constructions and maintenance and operation work in the contract, which motivates the private sector to build properties up to standard for its cost efficiency from the whole project perspective.
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Yongfu Chen, Wenbo Zhu and Ziyuan Chen
China is not only the biggest mutton consumer, but also the top mutton importer in the world. China’s urban households are becoming the key driving force behind a surge in mutton…
Abstract
Purpose
China is not only the biggest mutton consumer, but also the top mutton importer in the world. China’s urban households are becoming the key driving force behind a surge in mutton consumption. Therefore, the purpose of this paper is to investigate the determinants of mutton demand in urban China.
Design/methodology/approach
Based on a sample of 32,910 urban households across six provinces and autonomous regions, an inverse hyperbolic sine (IHS) double-hurdle model is estimated, by maximum likelihood estimation, to reveal the determinants of mutton consumption-at-home.
Findings
The empirical results indicate that, first, household income has a positive effect on mutton consumption, and higher income households have a higher income elasticity; second, wet weather increases probability, but reduces conditional level and unconditional level; finally, minority group households consume more mutton than Han group households.
Practical implications
It is necessary for policymakers to develop a long-term outlook in relation to the increase of China’s mutton appetite and to shift from a domestic perspective to a global one and develop diversified import strategies. Furthermore, policymakers require to make a practicable emergency preplan for tackling short-term agglomeration of demand for mutton, attributed to festivals, and religious events of a minority ethnic group.
Originality/value
This is a major work based on a large sample of 32,910 urban households conducted by the National Bureau of Statistics of China. This paper uses an IHS double-hurdle model to quantify the determinants of mutton consumption; it sheds light on the climatic, regional, and ethnic characteristics of mutton consumption in urban China.
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Peng Gao, Xiuqin Su and Wenbo Zhang
This study aims to promote the anti-disturbance and tracking accuracy of optoelectronic stabilized platforms, which ensure that optical detectors accurately track targets and…
Abstract
Purpose
This study aims to promote the anti-disturbance and tracking accuracy of optoelectronic stabilized platforms, which ensure that optical detectors accurately track targets and acquire high-quality images.
Design/methodology/approach
An improved active disturbance rejection control (ADRC) strategy based on model-assisted double extended state observers (MDESOs) is proposed in this paper. First, by establishing an auxiliary model, the total disturbances are separated into two parts: inner and external disturbances. Then, MDESOs are designed to estimate the two parts by separately using two parallel ESOs, by which the controlled plant is adjusted to the ideal pure integral series. Simultaneously, combined with the nonlinear state error feedback, an overall control strategy is established.
Findings
Compared with the conventional ADRC and proportional derivative, the improved ADRC (IADRC) has stronger robustness and adaptability and effectively reduces the requirements for model accuracy and the gain of the ESO. The error of the auxiliary model is tolerated to exceed 50%, and the parameter values of the MDESOs are reduced by 90%.
Originality/value
The total disturbance rejection rate of the proposed strategy is only 3.11% under multiple disturbances, which indicates that the IADRC strategy significantly promotes anti-disturbance performance.
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Yudan Dou, Xiaolong Xue, Yuna Wang, Weirui Xue and Wenbo Huangfu
This study aims to evaluate enterprise technology innovation capability in prefabricated construction (PC) from an input-output perspective, using six integrated enterprises in…
Abstract
Purpose
This study aims to evaluate enterprise technology innovation capability in prefabricated construction (PC) from an input-output perspective, using six integrated enterprises in China as cases.
Design/methodology/approach
An evaluation system for enterprise technology innovation capability in PC was constructed, including total input, technology output (TO) and project output. All the evaluation indexes were quantified, and the subject and object indexes weights were determined using the fuzzy cognitive map and information entropy, respectively. The final scores and ranks were evaluated through gray relational analysis (GRA) based on the combined weights.
Findings
It was found that enterprise technology innovation capability in PC was low in China, with its unbalanced development in different dimensions and the poorest performance in TO, currently.
Originality/value
This research has developed an evaluation system for technology innovation capability in PC at the enterprise level and scientifically quantified all the indexes, which is a breakthrough over existing studies. The GRA model based on the combined weights proposed in this study can be applied to other comparable fields and regions, with its easy operation.
Details
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Peng Gao, Xiuqin Su, Zhibin Pan, Maosen Xiao and Wenbo Zhang
This study aims to promote the anti-disturbance and tracking accuracy performance of the servo systems, in which a modified active disturbance rejection control (MADRC) scheme is…
Abstract
Purpose
This study aims to promote the anti-disturbance and tracking accuracy performance of the servo systems, in which a modified active disturbance rejection control (MADRC) scheme is proposed.
Design/methodology/approach
An adaptive radial basis function (ARBF) neural network is utilized to estimate and compensate dominant friction torque disturbance, and a parallel high-gain extended state observer (PHESO) is employed to further compensate residual and other uncertain disturbances. This parallel compensation structure reduces the burden of single ESO and improves the response speed of permanent magnet synchronous motor (PMSM) to hybrid disturbances. Moreover, the sliding mode control (SMC) rate is introduced to design an adaptive update law of ARBF.
Findings
Simulation and experimental results show that as compared to conventional ADRC and SMC algorithms, the position tracking error is only 2.3% and the average estimation error of the total disturbances is only 1.4% in the proposed MADRC algorithm.
Originality/value
The disturbance parallel estimation structure proposed in MADRC algorithm is proved to significantly improve the performance of anti-disturbance and tracking accuracy.