Bibo Yao, Zhenhua Li, Baoren Teng and Jing Liu
Laser powder bed fusion (LPBF) can be used to fabricate complex extrusion die without the limitation of structures. Layer-by-layer processing leads to differences in…
Abstract
Purpose
Laser powder bed fusion (LPBF) can be used to fabricate complex extrusion die without the limitation of structures. Layer-by-layer processing leads to differences in microstructures and wear properties. This study aims to investigate the microstructure evolution and effects of tungsten carbide (WC) on the wear properties of LPBF-printed 18Ni300.
Design/methodology/approach
Economical spherical granulation-sintering-deoxygenation (GSD) WC-reinforced 18Ni300 steel matrix composites were produced by LPBF from powder mixtures of WC and 18Ni300. The effects of WC contents on anisotropic microstructures and wear properties of the composites were investigated.
Findings
The relative density is more than 99% for all the composites except 25% WC/18Ni300 composite. The grain sizes distributed on the top cross-section are smaller than those on the side cross-section. After adding WC particles, more high-angle grain boundaries and larger Schmid factor generate, and deformed grains decrease. With increasing WC contents, the hardness first decreases and then increases but the wear volume loss decreases. The side cross-section of the composite has higher hardness and better wear resistance. The 18Ni300 exhibits adhesive wear accompanying with abrasive wear, while plowing and fatigue wear are the predominant wear mechanisms of the composites.
Originality/value
Economical spherical GSD WC particles can be used to improve the wear resistance. The novel WC/18Ni300 composites are suitable for the application under the abrasive wear condition with low stress.
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Keywords
Yu-Ting L.V., Yong Li, De-Xing Yang, Zhenhua Bai, Jinlong Li and Rui Wang
Continuous annealing (CA) units usually lack a physical shapemeter; consequently, real-time display and closed-loop control of the strip shape are impossible to achieve.
Abstract
Purpose
Continuous annealing (CA) units usually lack a physical shapemeter; consequently, real-time display and closed-loop control of the strip shape are impossible to achieve.
Design/methodology/approach
A shape model for the CA process is established in this study. Specifically, a virtual shapemeter and closed-loop control system based on the advanced parameter acquisition system and information transmission of CA units are developed in C++ programming language. This system realises real-time dynamic shape display, closed-loop control and shape prediction by collecting raw data of steel coils and parameters during CA.
Findings
Field test results show that the shape predicted by the virtual shapemeter coincides with the measured shape by over 90 per cent, which fully meets the precision requirement of industrial applications.
Originality/value
Moreover, shape quality is effectively improved without increasing hardware investments.
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Keywords
Zixin Mu, Zhenhua Cai, Chunnian Zeng, Zifan Li, Xufeng Liang, Fan Yang, Tingyang Chen, Shujuan Dong, Chunming Deng and Shaopeng Niu
During the process of the robotic grinding and polishing operations on aero-engine blades, the key problem of calibration error lies in fixture error and uneven margin. To solve…
Abstract
Purpose
During the process of the robotic grinding and polishing operations on aero-engine blades, the key problem of calibration error lies in fixture error and uneven margin. To solve this problem, this paper aims to propose a novel method to achieve rapid online calibration of the workpiece coordinate system through laser-based measurement techniques.
Design/methodology/approach
The authors propose a calibration strategy based on point cloud registration algorithm. The main principle is presented as follows: aero blade mounted on clamping end-effector is hold by industry robot, the whole device is then scanned by a 3D laser scanner to obtain its surface point cloud, and a fast segmentation method is used to acquire the point cloud of the workpiece. Combining Super4PCS algorithm with trimmed iterative closest point, we can align the key points of the scanned point cloud and the sampled points of the blade model, thus obtaining the translation and rotation matrix for calculating the workpiece coordinate and machining allowance. The proposed calibration strategy is experimentally validated, and the positioning error, as well as the margin distribution, is finally analyzed.
Findings
The experimental results show that the algorithm can well accomplish the task of cross-source, partial data and similar local features of blade point cloud registration with high precision. The total time spent on point cloud alignment of 100,000 order of magnitude blade is about 4.2 s, and meanwhile, the average point cloud alignment error is reduced to below 0.05 mm.
Originality/value
An improved point cloud registration method is proposed and introduced into the calibration process of a robotic system. The online calibration technique improves the accuracy and efficiency of the calibration process and enhances the automation of the robotic grinding and polishing system.
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This paper explores whether fintech paves the way for the transition to carbon neutrality in the context of China’s climate policy uncertainty (CCPU) and the influence of the…
Abstract
Purpose
This paper explores whether fintech paves the way for the transition to carbon neutrality in the context of China’s climate policy uncertainty (CCPU) and the influence of the ocean carbon sink market.
Design/methodology/approach
We apply a novel wavelet analysis technique to investigate the time-frequency dependence between the CCPU index, the CSI (China Securities Index) Fintech Theme Index (CFTI) and the Carbon Neutral Concept Index (CNCI).
Findings
The empirical results show that CCPU and CFTI have a detrimental effect on CNCI in high-frequency bands. Furthermore, in low-frequency domains, the development of CFTI can effectively promote the realization of carbon neutrality.
Practical implications
Our findings show that information from the CCPU and CFTI can be utilized to forecast the movement of CNCI. Therefore, the government should strike a balance between fintech development and environmental regulation and, hence, promote the use of renewable energy to reduce carbon emissions, facilitating the orderly and regular development of the ocean carbon sink market.
Originality/value
The development of high-quality fintech and positive climate policy reforms are crucial for achieving carbon neutrality targets and promoting the growth of the marine carbon sink market.
Details
Keywords
Xufeng Liang, Zhenhua Cai, Chunnian Zeng, Zixin Mu, Zifan Li, Fan Yang, Tingyang Chen, Shujuan Dong, Chunming Deng and Shaopeng Niu
The application of thermal barrier coatings (TBCs) allows aero-engine blades to operate at higher temperatures with higher efficiency. The preparation of the TBCs increases the…
Abstract
Purpose
The application of thermal barrier coatings (TBCs) allows aero-engine blades to operate at higher temperatures with higher efficiency. The preparation of the TBCs increases the surface roughness of the blade, which impacts the thermal cycle life and thermal insulation performance of the coating. To reduce the surface roughness of blades, particularly the blades with small size and complex curvature, this paper aims to propose a method for industrial robot polishing trajectory planning based on on-site measuring point cloud.
Design/methodology/approach
The authors propose an integrated robotic polishing trajectory planning method using point cloud processing technical. At first, the acquired point cloud is preprocessed, which includes filtering and plane segmentation algorithm, to extract the blade body point cloud. Then, the point cloud slicing algorithm and the intersection method are used to create a preliminary contact point set. Finally, the Douglas–Peucker algorithm and pose frame estimation are applied to extract the tool-tip positions and optimize the tool contact posture, respectively. The resultant trajectory is evaluated by simulation and experiment implementation.
Findings
The target points of trajectory are not evenly distributed on the blade surface but rather fluctuate with surface curvature. The simulated linear and orientation speeds of the robot end could be relatively steady over 98% of the total time within 20% reduction of the rest time. After polishing experiments, the coating roughness on the blade surface is reduced dramatically from Ra 7–8 µm to below Ra 1.0 µm. The removal of the TBCs is less than 100 mg, which is significantly less than the weight of the prepared coatings. The blade surface becomes smoothed to a mirror-like state.
Originality/value
The research on robotic polishing of aero-engine turbine blade TBCs is worthwhile. The real-time trajectory planning based on measuring point cloud can address the problem that there is no standard computer-aided drawing model and the geometry and size of the workpiece to be processed differ. The extraction and optimization of tool contact points based on point cloud features can enhance the smoothness of the robot movement, stability of the polishing speed and performance of the blade surface after polishing.
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Keywords
Xiping Liu, Ya Li, Zhangqi Liu, Tao Ling and Zhenhua Luo
The purpose of this paper is to propose a permanent magnet-assisted synchronous reluctance machine (PMASynRM) using ferrite magnets with the same power density as rare-earth PM…
Abstract
Purpose
The purpose of this paper is to propose a permanent magnet-assisted synchronous reluctance machine (PMASynRM) using ferrite magnets with the same power density as rare-earth PM synchronous motors used in Toyota Prius 2010.
Design/methodology/approach
A novel rotor structure with rectangular PMs is discussed with respect to the demagnetization of ferrite magnets and mechanical strength. Some electromagnetic characteristics including torque, output power, loss and efficiency are calculated by 2D finite element analysis.
Findings
The results of the analysis show that a high power density and high efficiency for PMASynRM can be achieved using ferrite magnets.
Originality/value
This paper proposes a novel rotor structure of PMASynRM with low-cost ferrite magnets that achieves high power density as permanent machines with rare-earth PMs.
Details
Keywords
Yongxin Zhou, Qian Li, Zhiguo Xing, Renze Zhou, Zhenhua Huang, Yanfei Huang and Weiling Guo
This paper aims to investigate the effect of aluminum addition on the microstructure and mechanical properties of Mg-8Gd-4Y-1Zn alloy.
Abstract
Purpose
This paper aims to investigate the effect of aluminum addition on the microstructure and mechanical properties of Mg-8Gd-4Y-1Zn alloy.
Design/methodology/approach
Mg-8Gd-4Y-1Zn-xAl (x = 0, 0.5, 1.0, 1.5, 2.0 Wt.%) alloys were prepared by the conventional gravity casting technology, and then microstructures, phase composition and mechanical properties were investigated by material characterization method, systematically.
Findings
Results show that the as-cast microstructure of Mg-8Gd-4Y-1Zn alloy mainly consists of a-Mg matrix as well as Mg12REZn (18 R LPSO structure), and island-like Mg3(RE, Zn) phase is distributed at the grain boundary. The addition of a small amount of Al (0.5 Wt.%) can decrease the content of island-like Mg3(RE, Zn) phase, but significantly increase the content of long-period stacking ordered (LPSO) structure, resulting in the improvement of both tensile strength and elongation of Mg-8Gd-4Y-1Zn alloy. However, the addition of excessive Al will consume Re element and decrease the amount of LPSO structure, leading to the decrease of tensile properties. When the content of Al is 0.5 Wt.%, the tensile strength and elongation are 225 MPa and 9.0% of Mg-8Gd-4Y-1Zn alloy, which are 14% and 29% higher than that of Mg-8Gd-4Y-1Zn alloy, respectively.
Originality/value
Adding aluminum to Mg-8Gd-4Y-1Zn alloy strengthens its mechanical properties. And the effect of Al content on the alloy strengthening. The formation mechanism of LPSO structure with different aluminum content was revealed.
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Keywords
In modern China, sports and nationalism always have close connection, and nationalism is the important reason for the promotion of Chinese sports. However, the relationship…
Abstract
In modern China, sports and nationalism always have close connection, and nationalism is the important reason for the promotion of Chinese sports. However, the relationship between Chinese sports and nationalism in globalised China could be much more examined by academics, as well as its influencing factors. This chapter selects the Beijing 2008 Olympic Games as the context and representative three Chinese sports heroes in the period of globalisation to study. The findings show that in some extent, Beijing 2008 Olympic Games and three Chinese sports heroes represent the national image of China in the globalised world, also bearing the burden of washing away historical humiliation and pursuing national glory. Furthermore, it is manifested that China have a complex nationalism in the process of hosting the 2008 Olympic Games. Under the influence of mass media, market economy and sports professionalisation, nationalism still exists in Chinese sports, but people gradually start to reflect on the ‘Juguo Tizhi’, the traditional Chinese sports system and the concept of ‘winning glory for the nation’. The relationship between Chinese nationalism and sports shows the important implications of rapid Chinese sports development.
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Keywords
Haize Pan, Bingfeng Yang, Yongwei Pan and Zhenhua Luo
As an effective measure for reducing energy consumption and achieving carbon neutrality, prefabricated building projects (PBPs) have attracted considerable attention in China…
Abstract
Purpose
As an effective measure for reducing energy consumption and achieving carbon neutrality, prefabricated building projects (PBPs) have attracted considerable attention in China. Although the Chinese Government has vigorously promoted PBPs, neither developers nor consumers have high recognition of PBPs. This study aimed to explore the decision-making behaviour of governments, developers and consumers in promoting the development of prefabricated buildings in China and to better optimise the incentive strategies for prefabricated buildings in China.
Design/methodology/approach
Based on prospect and evolutionary game theories, an evolutionary game model of three stakeholders in the development of PBPs – government, developers and consumers – was constructed. Combined with the system dynamics theory, the incentive policy behaviour and influencing factors of the three parties in the evolutionary game model were analysed.
Findings
The results showed that the initial probability of the three parties affects the decision-making behaviour of each party and that of other stakeholders. Government subsidies to developers are more sensitive than developers themselves. There is a certain threshold for the scope of government subsidies to consumers, and exceeding this threshold does not promote the development of PBPs. Based on the results, policy recommendations to the government, developers and consumers were proposed to enhance PBP development.
Originality/value
This study provides suggestions for governments to formulate reasonable incentive policies for prefabricated buildings and a specific theoretical basis for the sound development of prefabricated buildings.
Details
Keywords
Leipeng Zhang, Binghan Zhang, Bo Fan, Zhenhua Gao and Junyou Shi
This paper aims to focus on the liquefaction of soybean protein to obtain a homogeneous protein solution with a high solid/protein content but low viscosity, which may improve the…
Abstract
Purpose
This paper aims to focus on the liquefaction of soybean protein to obtain a homogeneous protein solution with a high solid/protein content but low viscosity, which may improve the bond properties and technological applicability of soybean protein adhesive.
Design/methodology/approach
The liquefactions of soybean protein in the presence of various amounts of sodium sulphite, urea and sodium dodecyl sulphate (SDS) are investigated, and their effects on the main properties of liquefied soybean protein and soybean protein adhesives are characterized by Fourier transform infrared spectroscopy (FT-IR), gel permeation chromatography (GPC), viscosity tracing and plywood evaluation. Meanwhile, the applicability of soybean protein adhesive composed of liquefied protein for particleboard is also investigated.
Findings
Soybean protein can be effectively liquefied to form a homogeneous protein solution with a soybean protein content of 25 per cent and viscosity as low as 772 mPa.s; the addition of sodium sulphite, urea and SDS are beneficial for the liquefaction of soybean protein and have important effects on the technological applicability and water resistance of the obtained adhesive. The optimal liquefying technology of soybean protein is obtained in the presence of 1.5 Wt.% of sodium sulphite, 5 Wt.% of urea, 1.5 Wt.% of SDS and 3 Wt.% of sodium hydroxide. The optimal soybean protein adhesive has the desired water resistance in terms of the boiling-dry-boiling aged wet bond strength, which is up to 1.08 MPa higher than the required value (0.98 MPa) for structural use according to the commercial standard JIS K6806-2003. The optimal liquefied protein has the great potential to prepare particleboard.
Research limitations/implications
The protein content of liquefied soybean protein is expected to further increase from 25 to 40 Wt.% or even higher to further reduce the hot-pressing cycle or energy consumption of wood composites bonded by soybean protein adhesives.
Practical implications
The soybean protein adhesive composed of optimal liquefied protein has potential use in the manufacturing of structural-use plywood and has comparable applicability as a commercial urea-formaldehyde resin for the manufacturing of common particleboard.
Social implications
Soybean protein adhesive is an environmentally safe bio-adhesive that does not lead to the release of toxic formaldehyde, and the renewable and abundant soybean protein can be used with higher value added by the application as wood adhesive.
Originality/value
A novel liquefaction approach of soybean protein is proposed, and the soybean protein adhesive based on the liquefied protein is obtained with good technological applicability and desired bond properties that extend the applications of the soybean protein adhesive from interior plywood to particleboard and exterior or structural plywood.