Zeqi Jiang, Jianhua Fang, Fei Chen, Boshui Chen and Kecheng Gu
This paper aims at understanding tribological properties of lubricating oils doped with zinc dithiophosphate(ZDDP) with and without electromagnetic field impact.
Abstract
Purpose
This paper aims at understanding tribological properties of lubricating oils doped with zinc dithiophosphate(ZDDP) with and without electromagnetic field impact.
Design/methodology/approach
The friction and wear properties of the oils formulated with zinc butyloctyl dithiophosphate (T202) or zinc dioctyl dithiophosphate (T203) under electromagnetic field or nonelectromagnetic field were evaluated on a modified four-ball tribotester. The characteristics of the worn surfaces obtained from electromagnetic or nonelectromagnetic field conditions were analyzed by scanning electronic microscopy, energy dispersive spectrometer and X-ray photoelectron spectroscopy. This paper focuses on understanding influence of electromagnetic field on lubrication effect of the ZDDP-formulated oils.
Findings
The electromagnetic field could effectively facilitate anti-wear and friction-reducing properties of the oils doped with T202 or T203 as compared to those without electromagnetism affection, and the T203-doped oils were more susceptible to the electromagnetic field. The improvement of anti-wear and friction-reducing abilities of the tested oils were mainly attributed to the promoted tribochemical reactions and the modification of the worn surfaces (forming Zn-Fe solid solution) induced by the electromagnetic field.
Originality/value
This paper has revealed that tribological performances of ZDDP-doped oils could be improved by the electromagnetic field and discussed its lubrication mechanisms. Investigating tribological properties of additives from the viewpoint of electromagnetics is a new attempt, which has significance not only for the choose and designing of additives in electromagnetic condition but also for development of tribological theories and practices.
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Sen Li, He Guan, Xiaofei Ma, Hezhao Liu, Dan Zhang, Zeqi Wu and Huaizhou Li
To address the issues of low localization and mapping accuracy, as well as map ghosting and drift, in indoor degraded environments using light detection and ranging-simultaneous…
Abstract
Purpose
To address the issues of low localization and mapping accuracy, as well as map ghosting and drift, in indoor degraded environments using light detection and ranging-simultaneous localization and mapping (LiDAR SLAM), a real-time localization and mapping system integrating filtering and graph optimization theory is proposed. By incorporating filtering algorithms, the system effectively reduces localization errors and environmental noise. In addition, leveraging graph optimization theory, it optimizes the poses and positions throughout the SLAM process, further enhancing map accuracy and consistency. The purpose of this study resolves common problems such as map ghosting and drift, thereby achieving more precise real-time localization and mapping results.
Design/methodology/approach
The system consists of three main components: point cloud data preprocessing, tightly coupled inertial odometry based on filtering and backend pose graph optimization. First, point cloud data preprocessing uses the random sample consensus algorithm to segment the ground and extract ground model parameters, which are then used to construct ground constraint factors in backend optimization. Second, the frontend tightly coupled inertial odometry uses iterative error-state Kalman filtering, where the LiDAR odometry serves as observations and the inertial measurement unit preintegration results as predictions. By constructing a joint function, filtering fusion yields a more accurate LiDAR-inertial odometry. Finally, the backend incorporates graph optimization theory, introducing loop closure factors, ground constraint factors and odometry factors from frame-to-frame matching as constraints. This forms a factor graph that optimizes the map’s poses. The loop closure factor uses an improved scan-text-based loop closure detection algorithm for position recognition, reducing the rate of environmental misidentification.
Findings
A SLAM system integrating filtering and graph optimization technique has been proposed, demonstrating improvements of 35.3%, 37.6% and 40.8% in localization and mapping accuracy compared to ALOAM, lightweight and ground optimized lidar odometry and mapping and LiDAR inertial odometry via smoothing and mapping, respectively. The system exhibits enhanced robustness in challenging environments.
Originality/value
This study introduces a frontend laser-inertial odometry tightly coupled filtering method and a backend graph optimization method improved by loop closure detection. This approach demonstrates superior robustness in indoor localization and mapping accuracy.
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Luo Yue, Yan Meng, Eunji Lee, Pengpeng Bai, Yingzhuo Pan, Peng Wei, Jie Cheng, Yonggang Meng and Yu Tian
The incorporation of phosphide additives is regarded as a highly effective strategy for enhancing the lubricative qualities of base oils. This study aims to assess the lubrication…
Abstract
Purpose
The incorporation of phosphide additives is regarded as a highly effective strategy for enhancing the lubricative qualities of base oils. This study aims to assess the lubrication behavior and efficacy of various phosphide additives in polyethylsiloxane (PES) through the employment of the Schwingum Reibung Verschleiss test methodology, across a temperature range from ambient to 300°C.
Design/methodology/approach
PES demonstrated commendable lubrication capabilities within the Si3N4/M50 system, primarily attributable to the Si-O frictional reaction film at the interface. This film undergoes disintegration as the temperature escalates, leading to heightened wear. Moreover, the phosphide additives were found to ameliorate the issues encountered by PES in the Si3N4/M50 system, characterized by numerous boundary lubrication failure instances. A chemical film comprising P-Fe-O was observed to form at the interface; however, at elevated temperatures, disintegration of some phosphide films precipitated lubrication failures, as evidenced by a precipitous rise in the coefficient of friction.
Findings
The results show that a phosphide reactive film can be formed and a reduction in wear rate is achieved, which is reduced by 64.7% from 2.98 (for pure PES at 300°C) to 1.05 × 10–9 μm3/N m (for triphenyl phosphite at 300°C).
Originality/value
The data derived from this investigation offer critical insights for the selection and deployment of phosphide additives within high-temperature lubrication environments pertinent to PES.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2024-0139/
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Amrit Raj Paul, Manidipto Mukherjee and Mohit Kumar Sahu
The purpose of this study is to investigate the deposition of SS–Al transitional wall using the wire arc directed energy deposition (WA-DED) process with a Cu interlayer. This…
Abstract
Purpose
The purpose of this study is to investigate the deposition of SS–Al transitional wall using the wire arc directed energy deposition (WA-DED) process with a Cu interlayer. This study also aims to analyse the metallographic properties of the SS–Cu and Al–Cu interfaces and their mechanical properties.
Design/methodology/approach
The study used transitional deposition of SS–Al material over each other by incorporating Cu as interlayer between the two. The scanning electron microscope analysis, energy dispersive X-ray analysis, X-ray diffractometer analysis, tensile testing and micro-hardness measurement were performed to investigate the interface characteristics and mechanical properties of the SS–Al transitional wall.
Findings
The study discovered that the WA-DED process with a Cu interlayer worked well for the deposition of SS–Al transitional walls. The formation of solid solutions of Fe–Cu and Fe–Si was observed at the SS–Cu interface rather than intermetallic compounds (IMCs), according to the metallographic analysis. On the other hand, three different IMCs were formed at the Al–Cu interface, namely, Al–Cu, Al2Cu and Al4Cu9. The study also observed the formation of a lamellar structure of Al and Al2Cu at the hypereutectic phase. The mechanical testing revealed that the Al–Cu interface failed without significant deformation, i.e. < 4.73%, indicating the brittleness of the interface.
Originality/value
The study identified the formation of HCP–Fe at the SS–Cu interface, which has not been previously reported in additive manufacturing literature. Furthermore, the study observed the formation of a lamellar structure of Al and Al2Cu phase at the hypereutectic phase, which has not been previously reported in SS–Al transitional wall deposition.