Guoxin Xie, Ziyi Cui, Lina Si and Dan Guo
This paper aims to introduce a series of experimental results which are the extension of our previous novel observations (Xie et al., Soft Matter, 2011), which could be helpful…
Abstract
Purpose
This paper aims to introduce a series of experimental results which are the extension of our previous novel observations (Xie et al., Soft Matter, 2011), which could be helpful for revealing the lubrication failure mechanism in bearings when they are exposed to an electrical environment.
Design/methodology/approach
An experimental apparatus where a ball was in contact with a glass disk coated with a semi-reflective chromium layer. A small volume of oil droplet was put into the microgap of the ball-disk contact. Then, a potential was applied onto the oil micropool formed by the droplet surrounding the contact region.
Findings
It has been found that destabilization of the low-conducting oil micropool around the contact region could be induced after applying a potential. Thin oil films could be drained out of the oil pool and spread on the tribopair surfaces, resulting in the depletion of the oil pool. When the applied potential was increased, the occurrence of spreading would be easier and its development would be more obvious. In contrast, the electrospreading behavior would be suppressed when the oil viscosity, contact load and oil pool size were increased. Thermocapillary force due to thermal effect as a result of the current flow near the oil pool border has been proposed as the main driving force for the spreading behavior. The influences of the operating parameters have been ascribed to the change of the electric current near the oil pool border as well as the corresponding variations in the temperature rise and the surface tension of the oil pool.
Originality/value
This is the first study to directly observe that the lubricant oil micropool around the contact region could deplete after applying a potential, potentially resulting in oil starvation in the contact region.
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Xianghao Zhang, Bicheng Dong, Weiyuan Zhang, Guoxin Yu, Dongwei Ma and Zhihua Hu
The structure and protective effect of Al-coated Nd-Fe-B magnets before and after grain boundary diffusion were studied to explore the feasibility of improving the corrosion…
Abstract
Purpose
The structure and protective effect of Al-coated Nd-Fe-B magnets before and after grain boundary diffusion were studied to explore the feasibility of improving the corrosion resistance of Nd-Fe-B magnets by Al coating and Al grain boundary diffusion.
Design/methodology/approach
The Al coating was deposited on sintered Nd-Fe-B magnets by magnetron sputtering, and then the Al-coated Nd-Fe-B magnets were put into the vacuum tube furnace for grain boundary diffusion process. The influence of Al coating and grain boundary diffusion process on the corrosion resistance of Nd-Fe-B magnets was investigated using electrochemical tests.
Findings
Results showed that the Al coating thickness increases, the corrosion current density of Al-coated magnets first increases and then decreases with increasing coating time. The Al coating particles transform from small millet shaped particles to equiaxed polygonal particles, and finally to big millet shaped particles with increasing coating time. The diffusion temperature has little effect on the corrosion potential, and the corrosion current density of Al-diffused magnets after grain boundary diffusion is much higher than that of Al-coated magnets before grain boundary diffusion. The corrosion potential and corrosion current density of magnets first increase, and then decrease with increasing tempering temperature.
Originality/value
As for high intrinsic coercivity Nd-Fe-B magnets, Poor preparation of Al coatings can result in Al coatings lacking protective properties, and the Al coating should be used cautiously as the surface protective coating of magnets. Grain boundary diffusion leads to the disappearance of Al coating, and reduces the corrosion resistance of Nd-Fe-B magnets, while tempering treatment can improve the corrosion resistance of Al-diffused magnets.
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Xiufeng Zhang, Jitao Dai, Xia Li, Huizi Li, Huiqun Fu, Guoxin Pan, Ning Zhang, Rong Yang and Jianguang Xu
This paper aims to develop a signal acquisition system of surface electromyography (sEMG) and use the characteristics of (sEMG) signal to interference action pattern.
Abstract
Purpose
This paper aims to develop a signal acquisition system of surface electromyography (sEMG) and use the characteristics of (sEMG) signal to interference action pattern.
Design/methodology/approach
This paper proposes a fusion method based on combining the coefficient of AR model and wavelet coefficient. It improves the recognition rate of the target action. To overcome the slow convergence speed and local optimum in standard BP network, the study presents a BP algorithm which combine with LM algorithm and PSO algorithm, and it improves the convergence speed and the recognition rate of the target action.
Findings
Experiments verify the effectiveness of the system from two aspects the target motion recognition rate and the corresponding reaction speed of the robotic system.
Originality/value
The study developed a signal acquisition system of sEMG and used the characteristics of (sEMG) signal to interference action pattern. The myoelectricity integral values are presented to determine the starting point and end point of target movement, which is more effective than using single sample point amplitude method.
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Guoxin Zhang, Kun Liu, Guangqiang Liu and Zhizhong Cao
The purpose of this study is to explain the effect of slab and roll initial temperatures on the wear characteristics of the surface of hot roll descaling rolls.
Abstract
Purpose
The purpose of this study is to explain the effect of slab and roll initial temperatures on the wear characteristics of the surface of hot roll descaling rolls.
Design/methodology/approach
The UMESHMOTION subroutine and the Arbitrary Lagrangian-Eulerian adaptive mesh technique are used to investigate the wear profile of the descale roll surface and to evaluate the effect of the slab and roll’s initial temperature on the wear depth.
Findings
Wear is more pronounced at the edges of the roll-slab contact area and less severe in the roll-body’s central region. A rise in the initial slab temperature from 1,337 K to 1,429 K results in a 67% rise in maximum wear depth and 52% in frictional stress. The peak wear region progressively shifted toward the center of the roll body. A rise in the initial roll temperature from 308.15 K to 673.15 K caused a 46% reduction in maximum wear depth and 73% in frictional stress. The location of the peak wear region remained primarily unchanged.
Originality/value
This study used the UMESHMOTIONI subroutine and the Arbitrary Lagrangian-Eulerian adaptive mesh technique in ABAQUS® to evaluate the quantitative correlation between the wear depth of the descaling roll surfaces and the initial temperatures of the slab and rolls. This study offers valuable insights into improving the wear of descaling roll surfaces.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-06-2024-0231/
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Peng Xia, Kunjie Li, Fangui Zeng, Xiong Xiao, Jianliang Zhang, Jianhua Xiang and Beilei Sun
Pyrolysis for coal gas generation changes the composition, pore structure, permeability and adsorption capacity of coal. This work aims to discuss the utilization of coal…
Abstract
Purpose
Pyrolysis for coal gas generation changes the composition, pore structure, permeability and adsorption capacity of coal. This work aims to discuss the utilization of coal pyrolysis on enhancing coalbed methane (CBM) production in the Gujiao area, Shanxi province, China.
Design/methodology/approach
This research was conducted mainly by the methods of thermogravimetry mass spectrometry (TG-MS) analysis, liquid nitrogen adsorption experiment and methane isothermal adsorption measurement.
Findings
The results can be concluded as that 400-700°C is the main temperature range for generating CH4. Pore volume and specific surface area increase with increasing temperature; however, the proportion of micro pore, transition pore and macro pore has no difference. The optimum temperature for enhancing CBM production should be letter than 600°C because the sedimentation of tar and other products will occupy some pores and fissures after 600°C.
Originality/value
Here in, to accurately recognize the suitable maximum temperature for heating development, a method enhancing CBM production, TG-MS, was adopted to analyze the products and the weight loss of coals with different ranks in the Gujiao area at temperature of 30-1,100°C. And then the pore structure, porosity, permeability, methane adsorption capacity and thermal maturity of coals during pyrolysis were investigated with increased temperature from 30°C to 750°C. On these bases, the favorable condition for enhancing CBM production and the thermal evolution of coal were recognized.
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Keywords
Jianfei Li, Mengxia Sun, Li Ren and Bei Li
The advent of the new retail era witnessed the consumers’ demand shift from on the traditional product quality to on the full supply chain service quality, and product service and…
Abstract
Purpose
The advent of the new retail era witnessed the consumers’ demand shift from on the traditional product quality to on the full supply chain service quality, and product service and service manufacturing is gradually taking shape. The purpose of this paper is to propose whether there is a “quality bridge” in the dynamic evolution process of retail service supply chain (RSSC) and discuss the system role, steady-state characteristics and dynamic evolution mechanism of service quality in this dynamic evolution process.
Design/methodology/approach
This paper proposes the dissipation system structure of the RSSC under the steady-state quality constraint, constructs a Markov chain model (MCM) for the evolution of the service quality of RSSC, and tests the objective existence of the steady-state distribution of the service quality by taking Chinese HJ retail enterprises as samples.
Findings
The research value of this study is summarized as follows. The research finds that the evolution of service quality of RSSC is a dynamic and non-linear growth process, which has significant characteristics of complex adaptability and steady-state convergence. The study finds that the quality evolution process of the RSSC is a steady-state convergence process, and there is a steady-state distribution of quality in its co-evolution, in which different process input levels have a significant positive impact on the stable level of quality state. The study finds that the steady state of quality plays a crucial role in the collaborative evolution of the RSSC, that is, when the service quality reaches a certain steady state distribution, the operating efficiency and profit level of the whole chain will show an “explosive” growth trend.
Originality/value
Quality bridge, an original concept in this paper, represents the role of quality steady-state in the operation of RSSC. Based on Markov chain and system simulation tools, this paper verifies the existence of steady-state service quality and its positive effect on the co-evolution and sustainable development of RSSC. When the service quality reaches a certain steady distribution, the operating efficiency and income level of the whole chain will show n trend of explosive growth.