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1 – 10 of 877The purpose of this paper is to explore how a neo-liberal nationalist discourse of China imagines the spatial identity of the post-1997 Hong Kong with reference to Lost in Hong…
Abstract
Purpose
The purpose of this paper is to explore how a neo-liberal nationalist discourse of China imagines the spatial identity of the post-1997 Hong Kong with reference to Lost in Hong Kong, a new Chinese middle-class film in 2015 with successful box office sales.
Design/methodology/approach
Textual analysis with the aid of psychoanalysis, postcolonial studies and semiotics is used to interpret the meaning of the film in this study. The study also utilizes the previous literature reviews about the formation of the Chinese national identity to help analyze the distinct identity of the Chinese middle class today.
Findings
The discussion pinpoints how the new Chinese middle class as neo-liberal nationalists take Hong Kong as a “bizarre national redemptive space”. While Hong Kong is cinematically constructed as such a national other, this paper argues that the Hong Kong in question stands not for itself but in a form of “reverse hallucination” for pacifying the new Chinese middle class’ trauma under the rapid neo-liberalization of China in the 1990s.
Originality/value
This paper shows the new of formation of the Chinese nationalist’s discourse, especially the new Chinese middle-class discourse on Hong Kong after 1997.
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Gang Wang, Xiaohui Liu, Changhong Mi, Huijuan Fan, Bo Xu and Xuefeng Bai
The purpose of this study was to investigate the microstructural evolution and hydrolytic stability of poly(phenylborosiloxane) (PPhBS) to further use and develop the oligomers as…
Abstract
Purpose
The purpose of this study was to investigate the microstructural evolution and hydrolytic stability of poly(phenylborosiloxane) (PPhBS) to further use and develop the oligomers as heat-resistant modifiers.
Design/methodology/approach
PPhBS was synthesized by direct co-condensation of boric acid (BA) and phenyltriethoxysilane (PTEOS). The structural evolution of PPhBS at high temperature was investigated by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), differential thermal analysis (DTA), in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and 29Si nuclear magnetic resonance (NMR) spectroscopy. In addition, the change in the morphology of the PPhBS powder was examined to demonstrate the evolution of the chemical bonds, and the hydrolytic stability of PPhBS was investigated by a combination of X-ray diffraction (XRD) analysis, measurement of the mass loss in water and FTIR spectroscopy.
Findings
The results revealed that a cross-linking network was gradually formed with increasing temperature through the condensation of the residual hydroxyl groups in PPhBS, and the Si-OH and B-OH bonds remained even at a high temperature of 450°C. Furthermore, heat treatment improved the hydrolytic stability of the oligomer. The hydrolysis of the B-O-B bonds in PPhBS was reversible, whereas the Si-O-Si and Si-O-B bonds were highly resistant to hydrolysis.
Practical implications
The prepared PPhBS can be used as a heat-resistant modifier in adhesives, sealants, coatings and composite matrices.
Originality/value
Investigation of the structural evolution of a polyborosiloxane at high temperature by DRIFTS is a novel approach that avoided interference from moisture in the air. The insoluble mass fraction and the FTIR spectrum of PPhBS washed with water were used to investigate the hydrolytic stability of PPhBS.
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Cheng Xiong, Bo Xu and Zhenqian Chen
This study aims to investigate the rarefaction effects on flow and thermal performances of an equivalent sand-grain roughness model for aerodynamic thrust bearing.
Abstract
Purpose
This study aims to investigate the rarefaction effects on flow and thermal performances of an equivalent sand-grain roughness model for aerodynamic thrust bearing.
Design/methodology/approach
In this study, a model of gas lubrication thrust bearing was established by modifying the wall roughness and considering rarefaction effect. The flow and lubrication characteristics of gas film were discussed based on the equivalent sand roughness model and rarefaction effect.
Findings
The boundary slip and the surface roughness effect lead to a decrease in gas film pressure and temperature, with a maximum decrease of 39.2% and 8.4%, respectively. The vortex effect present in the gas film is closely linked to the gas film’s pressure. Slip flow decreases the vortex effect, and an increase in roughness results in the development of slip flow. The increase of roughness leads to a decrease for the static and thermal characteristics.
Originality/value
This work uses the rarefaction effect and the equivalent sand roughness model to investigate the lubrication characteristics of gas thrust bearing. The results help to guide the selection of the surface roughness of rotor and bearing, so as to fully control the rarefaction effect and make use of it.
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This paper aims to investigate spontaneous movement of single droplet on chemically heterogeneous surfaces induced by the net surface tension, using the improved three-dimensional…
Abstract
Purpose
This paper aims to investigate spontaneous movement of single droplet on chemically heterogeneous surfaces induced by the net surface tension, using the improved three-dimensional (3D) lattice Boltzmann (LB) method.
Design/methodology/approach
D3Q19 Shan-Chen LB model is improved in this paper. Segmented particle distribution functions coupled with the P-R equation of state are introduced to maintain the higher accuracy and greater stability. In addition, exact difference method (EDM) is adopted to implement force term to predict the droplet deformation and dynamics.
Findings
The numerical results demonstrate that spontaneous movement of single droplet (=1.8 µm) along wedge-shaped tracks is driven by net surface tension. Advancing angle decreases instantaneously with time, while receding angle changes slightly first and then decreases rapidly. Wetting length is affected by vertex angle and wetting difference, whereas the final value is only dependent on the stronger wettability. Although the velocity of single droplet on wedge-shaped tracks can be increased by the larger vertex angle, it has a negative influence on the displacement. For the same wetting difference, vertex angle equal to 30º is an optimization strategy in this model. If the simulation length is extended enough, then the smaller vertex angle is beneficial for the droplet movement. In addition, a larger wetting difference is beneficial to spontaneous movement, which can speed up the droplet movement.
Originality/value
The proposed numerical model of droplet dynamics on chemically heterogeneous surfaces provides fundamental insights for the enhancement of drop-wise condensation heat transfer.
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Xin Kuang, Bifeng Yin, Jian Wang, Hekun Jia and Bo Xu
The purpose of this paper is to evaluate the dispersion stability and the wear properties of lubricating oil blends added with modified nanometer cerium oxide (CeO2) at high…
Abstract
Purpose
The purpose of this paper is to evaluate the dispersion stability and the wear properties of lubricating oil blends added with modified nanometer cerium oxide (CeO2) at high temperature.
Design/methodology/approach
In this paper, CeO2 was self-made and it was chemically modified. The dispersion stability of CeO2 in lubricating oil was studied. And the wear test of lubricating oil blends added with modified CeO2 was carried out at high temperature.
Findings
The results showed that CeO2 was successfully modified by oleic acid and stearic acid. The dispersion stability of modified CeO2 in lubricating oil was improved. Adding modified nano-CeO2 with the concentration less than 50 ppm into the lubricating oil can improve the wear properties of friction pairs in different extent. With the increase of the amount of CeO2, the wear properties increased first and then decreased. The lubricating oil blend added with 25 ppm CeO2 has the best wear properties.
Originality/value
The raw material CeO2 in this paper is self-made and its shape and size are well controlled. Research on the addition of nano-CeO2 to the engine low viscosity finished lubricants is lacking. It is of great significance to study the dispersion stability and tribological properties of nano-lubricants under the new background of low viscosity of lubricating oil and close to the real engine working conditions. It has certain significance to promote the development of nano-lubricants for engines.
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Bifeng Yin, Huiqin Zhou, Bo Xu and Hekun Jia
The purpose of this paper is to investigate the coupling mechanism of the roughness distribution characteristic and surface textures on the cylinder liner.
Abstract
Purpose
The purpose of this paper is to investigate the coupling mechanism of the roughness distribution characteristic and surface textures on the cylinder liner.
Design/methodology/approach
The cylinder liner-piston ring lubrication model with non-Gaussian roughness distribution surface was proposed in this paper to find the optimum cylinder liner surface. The motored engine tests were carried out to verify the simulation results.
Findings
The calculation and experiment results show that the large negative skewness surface has the optimal lubrication performance in the un-textured liner, while in the textured liner, the small negative skewness surface is more appropriate, which means surface textures couple with small negative skewness surface can improve the lubrication performance.
Originality/value
Although there are some works related to liner surface roughness and textures, the combine of roughness distribution and surface textures is not usually taken into account. Therefore, this research is different from others, as the present model considers with real non-Gaussian roughness distribution liners.
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Jun-Hui Chai, Jun-Ping Zhong, Bo Xu, Zi-Jian Zhang, Zhengxiang Shen, Xiao-Long Zhang and Jian-Min Shen
The high-pressure accumulator has been widely used in the hydraulic system. Failure pressure prediction is crucial for the safe design and integrity assessment of the…
Abstract
Purpose
The high-pressure accumulator has been widely used in the hydraulic system. Failure pressure prediction is crucial for the safe design and integrity assessment of the accumulators. The purpose of this study is to accurately predict the burst pressure and location for the accumulator shells due to internal pressure.
Design/methodology/approach
This study concentrates the non-linear finite element simulation procedure, which allows determination of the burst pressure and crack location using extensive plastic straining criterion. Meanwhile, the full-scale hydraulic burst test and the analytical solution are conducted for comparative analysis.
Findings
A good agreement between predicted and measured the burst pressure that was obtained, and the predicted failure point coincided very well with the fracture location of the actual shell very well. Meanwhile, the burst pressure of the shells increases with wall thickness, independent of the length. It can be said that the non-linear finite element method can be employed to predict the failure behavior of a cylindrical shell with sufficient accuracy.
Originality/value
This paper can provide a designer with additional insight into how the pressurized hollow cylinder might fail, and the failure pressure has been predicted accurately with a minimum error below 1%, comparing the numerical results with experimental data.
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Chengke Wu, Chunjiang Chen, Rui Jiang, Peng Wu, Bo Xu and Jun Wang
Employing multi-type laborers (MLs) is common in multinational and cross-culture projects (MPCs). Different attributes of MLs can lead to uncertain and dynamic laborer behaviors…
Abstract
Purpose
Employing multi-type laborers (MLs) is common in multinational and cross-culture projects (MPCs). Different attributes of MLs can lead to uncertain and dynamic laborer behaviors (i.e. behavioral diversities), which may cause project deviations. Previous studies do not consider the uncertainties or dynamics of behaviors adequately or they only provide general suggestions. The purpose of this paper is to combine system dynamics (SD) and agent-based modeling (ABM) to build an integrated model. The proposed ABM-SD can gain better understanding of MLs’ behavioral diversities, reveal the associated impacts and improve project management.
Design/methodology/approach
Based on extensively review in construction labor management and computer simulation, architecture is built to depict the relationships between the affecting factors of MLs’ behaviors, MLs’ behavioral diversities and project performance. Second, conceptual structures of the ABM-SD model are developed. Third, methods to implement the model in practice are introduced, focusing on data collection and model structure adjustment. Finally, the model is tested in a case study.
Findings
Different ML groups have distinctive behaviors which constantly change through interactions between MLs, engineers and external environment. Inadequate consideration of the diversities can result in inaccurate estimation of productivity, work quality and absenteeism, causing severe project deviations such as schedule delay, cost overrun and high absenteeism. On the other hand, using the ABM-SD model, the root causes of project deviations are analyzed from the perspective of MLs’ behavioral diversities and the optimization of labor management can significantly improve project performance.
Research limitations/implications
This paper supplements previous studies because the ABM-SD model takes fully use of the strength of simulation of solving uncertain and dynamic problems and combines both qualitative and quantitative findings in existing studies of labor management. Besides, the ABM-SD model is also a practical management tool to better monitor laborer behaviors and forecast the impacts. The limitation is mainly about the small scale of the case study. However, the ABM-SD model already demonstrates the mechanism about how MLs’ different behaviors affect a project, which fulfill the aim of the study.
Practical implications
The ABM-SD model can simulate MLs’ behavioral diversities and produce reliable estimations of project performance. It also allows to optimize management plans. Furthermore, The ABM-SD model is adjustable based on specific project conditions, which make it applicable for different tasks, different laborer compositions and even different projects. Thus, the ABM-SD model can be a practical tool for engineers in MCPs.
Originality/value
SD and ABM are applied to study behaviors with well-known benefits in both separated and integrated manner. However, few studies use the approach to investigate MLs’ behaviors in MCPs. Hence, the proposed ABM-SD model is an original attempt to improve the laborer management level in MCPs.
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Bifeng Yin, Xuefeng Wang, Bo Xu, Gongyin Huang and Xin Kuang
The purpose of this paper was to improve the frictional wear resistance properties of piston skirts caused by the low viscosity lubricant by studying the tribological performance…
Abstract
Purpose
The purpose of this paper was to improve the frictional wear resistance properties of piston skirts caused by the low viscosity lubricant by studying the tribological performance of three novel coating materials.
Design/methodology/approach
Comparative tribological examinations were performed in a tribological tester using the ring-block arrangement under two viscosity lubricants, the loading force was applied as 100 N, the speed was set to 60 r/min and the testing time was 180 min.
Findings
Under low viscosity lubricant, the friction coefficient and wear of the three coatings all increase, and the friction coefficient and wear of the PTFE coating are the largest, while the MoS2 coating has the lowest friction coefficient and wear. Under low viscosity lubricant, the friction coefficient of the MoS2 coating is 2.1%–5.4% and 20.0%–24.3% lower than that of the SiO2 and PTFE coating, respectively. The friction coefficient and wear fluctuation rate of the MoS2 coating is the smallest when the lubricant viscosity decreases, which indicates that the MoS2 coating has excellent stability and adaptability under low viscosity lubricant.
Originality/value
To reduce the piston skirt wear caused by low viscosity lubricant in heavy-duty diesel engines, the friction and wear adaptability of three novel composite coating materials for piston skirts were compared under 0 W-20 low viscosity lubricant, which could provide a guidance for the application of wear-resistant materials for heavy-duty diesel engine piston skirt.
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Cheng Xiong, Bo Xu, Yulong Jiang, Xiangyu Lu and Zhenqian Chen
This study aims to investigate the thermohydrodynamic (THD) and thermoelastohydrodynamic (TEHD) performance of an air-lubricated thrust bearing under different slip conditions…
Abstract
Purpose
This study aims to investigate the thermohydrodynamic (THD) and thermoelastohydrodynamic (TEHD) performance of an air-lubricated thrust bearing under different slip conditions, especially the slip length effect.
Design/methodology/approach
In this study, a new modified boundary slip model was established to investigate thrust bearing performance. The THD and TEHD bearing characteristic distribution was analyzed with fluid–thermal–structure interaction approach. The effect of the slip length on the bearing performance was studied using various bearing structure parameters.
Findings
The increased slip length changed the classical feature distribution of the film pressure and temperature. The sacrifice of the bearing load capacity effectively compensated for the aerodynamic thermal effect and friction torque under the slip condition. The TEHD model has a lower film pressure and load capacity than the THD model. However, it also has lower film temperature, lower friction torque and smaller Knudsen number (Kn).
Originality/value
The bearing THD and TEHD performances of the modified boundary slip model were compared with those of a traditional no-slip bearing. The results help to guide the selection of the bearing surface materials and processing technology of rotor and foil, so as to fully control the degree of slip and make use of it.
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