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1 – 10 of over 7000Xiao-xiao Liu, Hui-hui Liu, Guo-liang Yang and Jiao-feng Pan
The high-quality development of the real estate industry is crucial to the transformation of China's economy. However, few studies apply the productivity to explore the…
Abstract
Purpose
The high-quality development of the real estate industry is crucial to the transformation of China's economy. However, few studies apply the productivity to explore the development path of the real estate industry in China. To fill this gap, this study mainly investigates the total factor productivity (TFP) of the real estate industry of 30 sample provinces in mainland China from 2007 to 2016.
Design/methodology/approach
The Malmquist index is applied to estimate the productivity (i.e. TFP) of the real estate industry, based on the data envelopment analysis (DEA). Then, the truncated tobit regression analysis explores the external influencing factors on the TFP of the real estate industry.
Findings
Through empirical analysis, it is found that the high-quality development of the real estate industry depends on the technological innovation by the real estate enterprises and the targeted policies by the provincial government. Moreover, the development of the real estate industry has a positive correlation with the growth of China's economy but a negative correlation with the development of other industries.
Practical implications
TFP mainly reveals the development status of the provincial real estate industry and identifies the driving force for exploring the high-quality development mode of the real estate sector. Furthermore, the fluctuation rule of TFP can be applied to predict the development trend of the real estate industry in the future.
Originality/value
As an application, this study measures the TFP of the Chinese real estate industry in different provinces and periods. The results have meaningful policy implications for policymakers regulating the real estate industry.
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Chi Zhang, Dajiang Zheng, Guang-Ling Song, Yang Guo, Ming Liu and Hamid Kia
This study aims to propose a simple experimental method to distinguish the galvanic corrosion, crevice corrosion and self-corrosion in metal/carbon fiber reinforced polymer (CFRP…
Abstract
Purpose
This study aims to propose a simple experimental method to distinguish the galvanic corrosion, crevice corrosion and self-corrosion in metal/carbon fiber reinforced polymer (CFRP) joints.
Design/methodology/approach
The corrosion behaviors of four different galvanic couples, whose anodes were Zn-coated DP590 steel and Al 6022, and cathodes were two kinds of CFRP, were investigated in immersion and GMW14872 cyclic conditions.
Findings
The results showed that the galvanic corrosion caused by direct contact between CFRP and metals was more serious than that caused by the jointing bolts. The corrosion damage caused by crevice corrosion was severer than that caused by galvanic corrosion. Self-corrosion was also significant, particularly under the cyclic salt spray condition.
Practical implications
Cyclic salt spray test may more reliably simulate the galvanic corrosion of a joint in industrial service environments, and real corrosion damage may be underestimated by a galvanic current measurement.
Originality/value
A deeper understanding of different corrosion mechanisms involved in CFRP/metal joints under different service conditions in industry has been given.
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Yang Guo, Huseini S. Patanwala, Brice Bognet and Anson W.K. Ma
This paper aims to summarize the latest developments both in terms of theoretical understanding and experimental techniques related to inkjet fluids. The purpose is to provide…
Abstract
Purpose
This paper aims to summarize the latest developments both in terms of theoretical understanding and experimental techniques related to inkjet fluids. The purpose is to provide practitioners a self-contained review of how the performance of inkjet and inkjet-based three-dimensional (3D) printing is fundamentally influenced by the properties of inkjet fluids.
Design/methodology/approach
This paper is written for practitioners who may not be familiar with the underlying physics of inkjet printing. The paper thus begins with a brief review of basic concepts in inkjet fluid characterization and the relevant dimensionless groups. Then, how drop impact and contact angle affect the footprint and resolution of inkjet printing is reviewed, especially onto powder and fabrics that are relevant to 3D printing and flexible electronics applications. A future outlook is given at the end of this review paper.
Findings
The jettability of Newtonian fluids is well-studied and has been generalized using a dimensionless Ohnesorge number. However, the inclusion of various functional materials may modify the ink fluid properties, leading to non-Newtonian behavior, such as shear thinning and elasticity. This paper discusses the current understanding of common inkjet fluids, such as particle suspensions, shear-thinning fluids and viscoelastic fluids.
Originality/value
A number of excellent review papers on the applications of inkjet and inkjet-based 3D printing already exist. This paper focuses on highlighting the current scientific understanding and possible future directions.
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Jie Tang, Yi Gong and Zhen-Guo Yang
The submitted paper is mainly concerned with the cracking of blind and buried vias of printed circuit board (PCB) for smartphones which were encountered with abnormal display…
Abstract
Purpose
The submitted paper is mainly concerned with the cracking of blind and buried vias of printed circuit board (PCB) for smartphones which were encountered with abnormal display problems like scramble display or no display during service and had to be recalled.
Design/methodology/approach
To found out the root causes of this failure and dissolve this commercial dispute, comprehensive failure analysis was performed on the printed circuit board assemblies (PCBAs) and PCBs of the failed smartphone, such as macrograph and micrograph observation, chemical compositions analysis, thermal performance testing and blind via pull-off experiment, which finally helped to determine the causes. Besides that, the failure mechanisms were discussed in detail, and pertinent countermeasures were proposed point by point.
Findings
It was found that the PCB blind vias cracking was the main reason for the scramble display or no display of the smartphone, and the incomplete cleaning process before copper plating was the root cause of the blind vias cracking.
Practical implications
Achievement of this paper would not only help to provide the solid evidence for determining the responsibility of this commercial dispute but also lead to a better understanding of the failure mechanisms and prevention methods for similar failure cases of other advanced mobile phones.
Originality/value
Most failure analysis researches of PCBAs only focused on the unqualified products from manufacturing, while this paper addressed a failure analysis case of PCBAs products for smartphones from actual services, which was relatively rarely reported in the past.
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Yao-yao Song, Hui-hui Liu, Xiao-xiao Liu and Guo-liang Yang
This paper aims to measure Chinese regional thermal industries’ evolution.
Abstract
Purpose
This paper aims to measure Chinese regional thermal industries’ evolution.
Design/methodology/approach
This paper uses data envelopment analysis (DEA) and global Malmquist–Luenberger productivity (GMLP) index.
Findings
The results reveal that the development of Chinese thermal power industry varies significantly in different regions, and it is highly correlated with the level of local economic development. Although the change of technical efficiency and scale efficiency had different impacts on different regions from year to year, the overall GMLP index change shows a close relationship with the contemporaneous frontier shift.
Practical implications
The results indicate that the Chinese Government should make efforts to promote its policy implementations and regulations in thermal industries so that the contemporaneous frontier will shift toward the global technology frontier with more desirable outputs and less undesirable outputs.
Originality/value
As an application, this study uses DEA and GMLP index to measure the productivity of Chinese thermal industries in 30 Chinese provinces from 2006 to 2013. The results have the meaningful policy implications for decision makers in charge of Chinese thermal industries.
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Keywords
Shuanbao Yao, Dawei Chen and Sansan Ding
The nose length is the key design parameter affecting the aerodynamic performance of high-speed maglev train, and the horizontal profile has a significant impact on the…
Abstract
Purpose
The nose length is the key design parameter affecting the aerodynamic performance of high-speed maglev train, and the horizontal profile has a significant impact on the aerodynamic lift of the leading and trailing cars Hence, the study analyzes aerodynamic parameters with multi-objective optimization design.
Design/methodology/approach
The nose of normal temperature and normal conduction high-speed maglev train is divided into streamlined part and equipment cabin according to its geometric characteristics. Then the modified vehicle modeling function (VMF) parameterization method and surface discretization method are adopted for the parametric design of the nose. For the 12 key design parameters extracted, combined with computational fluid dynamics (CFD), support vector machine (SVR) model and multi-objective particle swarm optimization (MPSO) algorithm, the multi-objective aerodynamic optimization design of high-speed maglev train nose and the sensitivity analysis of design parameters are carried out with aerodynamic drag coefficient of the whole vehicle and the aerodynamic lift coefficient of the trailing car as the optimization objectives and the aerodynamic lift coefficient of the leading car as the constraint. The engineering improvement and wind tunnel test verification of the optimized shape are done.
Findings
Results show that the parametric design method can use less design parameters to describe the nose shape of high-speed maglev train. The prediction accuracy of the SVR model with the reduced amount of calculation and improved optimization efficiency meets the design requirements.
Originality/value
Compared with the original shape, the aerodynamic drag coefficient of the whole vehicle is reduced by 19.2%, and the aerodynamic lift coefficients of the leading and trailing cars are reduced by 24.8 and 51.3%, respectively, after adopting the optimized shape modified according to engineering design requirements.
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Daochun Li, Shijun Guo, Tariq Osman Aburass, Daqing Yang and Jinwu Xiang
The purpose of this study is to develop an active controller of both leading-edge (LE) and trailing-edge (TE) control surfaces for an unmanned air vehicle (UAV) with a composite…
Abstract
Purpose
The purpose of this study is to develop an active controller of both leading-edge (LE) and trailing-edge (TE) control surfaces for an unmanned air vehicle (UAV) with a composite morphing wing.
Design/methodology/approach
Instead of conventional hinged control surfaces, both LE and TE seamless control surfaces were integrated with the wing. Based on the longitudinal state space equation, the root locus plot of the morphing wing aircraft, with a stability augmented system, was constructed. Using the pole placement, the feedback gain matrix for an active control was obtained.
Findings
The aerodynamic benefits of a morphing wing section are compared with a wing of a rigid control surface. However, the 3D morphing wing with a large sweptback angle produces a washout negative aeroelastic effect, which causes a significant reduction of the control effectiveness. The results show that the stability augmentation system can significantly improve the longitudinal controllability of an aircraft with a morphing wing.
Practical implications
This study is necessary to analyse the effect of a morphing wing on an UAV and perform a comparison with the rigid model.
Originality/value
The control surfaces assignment plan for trim, pitch and roll control was obtained. An active control algorism for the morphing wing was created to satisfy the required stability and control effectiveness by operating the LE and TE control surfaces according to flight conditions. The aeroelastic effect of control derivatives on the morphing aircraft was considered.
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Chaofan Jia, Shaolin Li, Xiuhua Guo, Juanhua Su and Kexing Song
The effect of different service parameters on the current-carrying tribological properties of CF-Al2O3/Cu composites was investigated, and the damage behavior of the composites…
Abstract
Purpose
The effect of different service parameters on the current-carrying tribological properties of CF-Al2O3/Cu composites was investigated, and the damage behavior of the composites under different service parameters was probed. The purpose of this study is to provide a theoretical basis for the application of CF-Al2O3/Cu composites.
Design/methodology/approach
The composites were fabricated by internal oxidation combined with powder metallurgy. The current-carrying tribological properties of CF-Al2O3/Cu composites were investigated on an electrical damage test system at different loads and currents.
Findings
As the load increases, the wear mechanism of the composite changes from abrasive wear to delamination wear. As the current increases, the oxidation wear and arc erosion of the composites gradually intensified. Under the service parameters of 0–25 A and 30–40 N, the composite has relatively stable current-carrying tribological properties.
Originality/value
This paper could provide a theoretical basis for the practical application of CF-Al2O3/Cu composites.
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Keywords
Shuai Yang, Junxing Hou, Xiaodong An and Shuanghui Xi
The floating ring generates elastic deformation as the film pressure for high-speed floating ring bearings (FRBs). The purpose of this study is to investigate the influence of…
Abstract
Purpose
The floating ring generates elastic deformation as the film pressure for high-speed floating ring bearings (FRBs). The purpose of this study is to investigate the influence of ring elastic deformation on the performance of a hydrodynamic/hydrostatic FRB, including floating ring equilibrium and minimum film thickness.
Design/methodology/approach
The finite element method and finite difference method are used to solve thermohydrodynamic (THD) lubrication models, including the Reynolds equation, energy equation and temperature–viscosity equation. The deformation matrix method is applied to solve the elastic deformation equation, and then the deformation distribution, floating ring equilibrium and minimum film thickness are investigated. The maximum pressure is compared with the published article to verify the mathematical models.
Findings
The deformation value increases with the growth of shaft speed; owing to elastic deformation on the film reaction force and friction moment, the ring achieves equilibrium at a new position, and the inner eccentricity increases while the ring-shaft speed ratio declines. The minimum film thickness declines with the growth of inlet temperature, and the outer film tends to rupture considering elastic deformation at a higher temperature.
Originality/value
The floating ring elastic deformation is coupled with the THD lubrication equations to study ring deformation on the hydrodynamic/hydrostatic FRB lubrication mechanism. The elastic deformation of floating ring should be considered to improve analysis accuracy for FRBs.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2023-0139/
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De-gan Zhang, Ya-meng Tang, Yu-ya Cui, Jing-xin Gao, Xiao-huan Liu and Ting Zhang
The communication link in the engineering of Internet of Vehicle (IOV) is more frequent than the communication link in the Mobile ad hoc Network (MANET). Therefore, the highly…
Abstract
Purpose
The communication link in the engineering of Internet of Vehicle (IOV) is more frequent than the communication link in the Mobile ad hoc Network (MANET). Therefore, the highly dynamic network routing reliability problem is a research hotspot to be solved.
Design/methodology/approach
The graph theory is used to model the MANET communication diagram on the highway and propose a new reliable routing method for internet of vehicles based on graph theory.
Findings
The expanded graph theory can help capture the evolution characteristics of the network topology and predetermine the reliable route to promote quality of service (QoS) in the routing process. The program can find the most reliable route from source to the destination from the MANET graph theory.
Originality/value
The good performance of the proposed method is verified and compared with the related algorithms of the literature.
Details