Chunjie Wei, Qi Chen, Jimin Xu, Xiaojun Liu and Wei Wang
The purpose of this paper is to explore the operating characteristics of gallium-based liquid metals (GLMs) by directly adding them as lubricants in real mechanical equipment.
Abstract
Purpose
The purpose of this paper is to explore the operating characteristics of gallium-based liquid metals (GLMs) by directly adding them as lubricants in real mechanical equipment.
Design/methodology/approach
This paper conducts an analysis of the rotor-bearing system under GLM lubrication using a constructed test rig, focusing on vibration signals, surface characteristics of the friction pair, contact resistance and temperature rise features.
Findings
The study reveals that GLM can effectively improve the lubrication condition of the tribo-pair, leading to a more stable vibration signal in the system. Surface analysis demonstrates that GLM can protect the sample surface from wear, and phase separation occurs during the experimental process. Test results of contact resistance indicate that, in addition to enhancing the interfacial conductivity, GLM also generates a fluid dynamic pressure effect. The high thermal conductivity and anti-wear effects of GLM can reduce the temperature rise of the tribo-pair, but precautions should be taken to prevent oxidation and the loss of its fluidity.
Originality/value
The overall operating characteristics of the rotor-bearing system under GLM lubrication were investigated to provide new ideas for the lubrication of the rotor-bearing system.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-03-2024-0067/
Details
Keywords
Baoxuan Liu, Yu Feng, Shaolei Wu, Chunjie Wei and Wei Wang
This paper aims to investigate the damage evolution of bearing raceways under impact conditions from the perspective of three-dimensional (3D) surface morphology changes and to…
Abstract
Purpose
This paper aims to investigate the damage evolution of bearing raceways under impact conditions from the perspective of three-dimensional (3D) surface morphology changes and to analyze the causal factors with the aid of simulation.
Design/methodology/approach
An experimental device containing an impact generating mechanism, a transmission mechanism and a torque load is designed for the experiments of impact damage to the outer raceway of a small needle roller bearing HK1208 without an inner ring. Microscopic images and height color maps of each experimental stage were obtained using a 3D laser measurement microscope. The characterization parameters of the surface 3D morphology were extracted and analyzed. Dynamics simulations of the impact condition were performed using the finite element method to investigate the variations and distribution characteristics of the roller forces on the raceway.
Findings
The changes in roughness and 3D micromorphology show that the surface flattening phenomenon caused by the flattening effect occurs before the surface of the bearing raceway is damaged. The result of dynamic simulations shows that the maximum load of the bearing under the impact state is obviously greater than that under a steady state, and the load distribution under the two conditions is significantly different.
Originality/value
This paper provides new ideas for analyzing the damage of bearings under impact conditions by analyzing the real 3D morphology of bearing raceways in combination with the finite element method.
Details
Keywords
Wang Zhizhong, Han Chao, Guosheng Huang, Han Bin and Han Bin
The deposition of particles onto a substrate during the cold spraying (CS) process relies on severe plastic deformation, so there are various micro-defects induced by insufficient…
Abstract
Purpose
The deposition of particles onto a substrate during the cold spraying (CS) process relies on severe plastic deformation, so there are various micro-defects induced by insufficient deformation and severe crushing. To solve the problems, many post-treat techniques have been used to improving the quality by eliminating the micro-defects. This paper aims to help scholars and engineers in this field a better and systematic understand of CS technology by summarizing the post-treatment technologies that have been investigated recently years.
Design/methodology/approach
This review summarizes the types of micro-defects and introduces the effect of micro-defects on the properties of CS coating/additive manufactured, illustrates the post-treatment technologies and its effect on the microstructure and performances, and finally outlooks the future development trends of post-treatments for CS.
Findings
There are significant discoveries in post-treatment technology to change the performance of cold spray deposits. There are also many limitations for post-treatment methods, including improved performance and limitations of use. Thus, there is still a strong requirement for further improvement. Hybrid post-treatment may be a more ideal method, as it can eliminate more defects than a single method. The proposed ultrasonic impact treatment could be an alternative method, as it can densify and flatten the CS deposits.
Originality/value
It is the first time to reveal the influence factors on the performances of CS deposits from the perspective of microdefects, and proposed corresponding well targeted post-treatment methods, which is more instructive for improving the performances of CS deposits.
Details
Keywords
Fashu Xu, Rui Huang, Hong Cheng, Min Fan and Jing Qiu
This paper aims at the problem of attaching the data of doctors, patients and the real-time sensor data of the exoskeleton to the cloud in intelligent rehabilitation applications…
Abstract
Purpose
This paper aims at the problem of attaching the data of doctors, patients and the real-time sensor data of the exoskeleton to the cloud in intelligent rehabilitation applications. This study designed the exoskeleton cloud-brain platform and validated its safety assessment.
Design/methodology/approach
According to the dimension of data and the transmission speed, this paper implements a three-layer cloud-brain platform of exoskeleton based on Alibaba Cloud's Lambda-like architecture. At the same time, given the human–machine safety status detection problem of the exoskeleton, this paper built a personalized machine-learning safety detection module for users with the multi-dimensional sensor data cloned by the cloud-brain platform. This module includes an abnormality detection model, prediction model and state classification model of the human–machine state.
Findings
These functions of the exoskeleton cloud-brain and the algorithms based on it were validated by the experiments, they meet the needs of use.
Originality/value
This thesis innovatively proposes a cloud-brain platform for exoskeletons, beginning the digitalization and intelligence of the exoskeletal rehabilitation process and laying the foundation for future intelligent assistance systems.
Details
Keywords
Embial Asmamaw Aschale and Habtamu Bishaw Asres
The purpose of this paper is to examine expropriation, valuation, compensation and rehabilitation practices and their impacts on expropriated households.
Abstract
Purpose
The purpose of this paper is to examine expropriation, valuation, compensation and rehabilitation practices and their impacts on expropriated households.
Design/methodology/approach
This study employed a mixed research approach. The target populations of the study were expropriated households in Debre Markos City from 2019 to 2022. The study uses purposive and systematic random sampling techniques. The data were analyzed using descriptive statistics, narration and thematic clustering.
Findings
The findings of this study revealed that the expropriation process was not participatory and the right holders were not treated as what is expected. It is further found that economic losses, moral damage and social disturbance payments were not considered in the compensation package. The displacement compensation given was also inadequate and sometimes delayed and the time value of money was not taken into account for delayed payments. This creates social and economic problems. The rehabilitation and resettlement program was inadequate and ineffective. The expropriation, valuation, compensation and rehabilitation practice in general lack transparency and accountability.
Practical implications
To ensure efficient and effective expropriation, valuation and compensation, there should be a well-organized government system that provides an accurate valuation on the one hand and restores the livelihood of the displaced on the other.
Originality/value
This paper is the first on expropriation, valuation, compensation and rehabilitation within the framework of transparency, accountability, effective rehabilitation and resettlement and institutional arrangements to ensure the sustainable livelihoods of affected households.