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The purpose of constructing a degradation index (DI) is to better characterize the degradation degree of mechanical transmission compared with relying solely on spectral oil data, which leads to an accurate estimation of the failure time when the transmission no longer fulfills its function.

The DI is modeled using a weighted average function with two desirable properties: maximizing the monotonic trend and minimizing the variance of failure threshold between different transmissions. The method includes concentration modification, data selection and data fusion steps that lead to a reasonable mechanical transmission degradation model. The proposed methodology was verified through a case study involving multispectral oil data sampled from several power-shift steering transmissions.

The results show that the DI outperforms all spectral oil data. Compared with the existing spectral oil data-based degradation modeling approach for mechanical transmissions, the present methodology provides an accurate RUL prediction.

There are several important directions for future research: First, more degradation data (i.e. ferrography) that are tailored to the degradation modeling of mechanical transmission need to be involved. Second, more effective degradation data selection methodologies that are applicable for multiple data types need to be developed. Third, kernel methods that can fuse the nonlinear degradation data need to be investigated.

The novelty of this methodology lies in integrating the multiple degradation data in a unified DI. And the main contribution of this paper is to establish a new direction in degradation modeling and RUL prediction of mechanical transmission.

This paper aims to explore the effect of automatic transmission fluid (ATF) temperature on the dynamic friction-wear properties of the friction component in a wet multi-disc clutch during the running-in process.

The running-in evolution was explored in terms of global friction performance and instantaneous friction characteristics. The variation of friction torque of the initial 300 engagement cycles was obtained by wet-clutch tests. Finally, an optical microscope was used to detect the wear mechanism of friction surfaces.

The ATF temperature showed a significant effect on the friction-wear performance in the clutch running-in process. The mean coefficient of friction decreased with the increase of the ATF temperature and decreased rapidly in the approximately initial 60 clutch engagements. The higher the ATF temperature was, the thinner the ATF film was, and more asperity summits were cut, thus leading to a smoother surface. Considering the slightly instantaneous friction fluctuation and the wear performance, a proper ATF temperature is necessary.

The results provide theoretical guidance for selecting the optimal ATF temperature during the running-in process.

In armored vehicles integrated transmissions, residual life prediction based on oil spectrum data is crucial for condition monitoring and reliability assessment. This paper aims to use the advantages of real-time and accurate prediction of binary Wiener process, the residual life prediction of clutch is studied.

First, combined with the wet clutch life test, the indicator elements Cu and Pb and the failure threshold of the residual life prediction of the clutch are extracted through the oil replacement correction of the spectral data of the whole life cycle; second, the correlation characteristics of indicating elements are analyzed by MATLAB Copula function, then the correlation function of residual life will be derived; third, according to the inverse Gaussian principle, the performance degradation mathematical models of the unary and binary Wiener processes of the above two indicator elements are established; finally, the maximum likelihood estimation method is used to estimate the parameters, and the monadic and binary performance degradation mathematical models are used to predict the residual life of the tested clutch.

By comparing the prediction results with the test results, with the passage of time, 81.25% of the predicted value error of the residual life prediction method based on the binary Wiener process is controlled within 20%, while 56.25% of the predicted value error of the residual life prediction method based on the unitary Wiener process is controlled within 20%. At the same time, the prediction accuracy of the binary prediction model is 2%–16.7% higher than that of the unitary prediction model.

This paper studies the residual life prediction theory of wet clutch, which can develop the theory and method of comprehensive transmission health monitoring, and provide theoretical and technical support for the construction of a reliable health management system for high-speed tracked vehicles.

This paper intends to provide a thematic literature review of the scholarly research articles orbiting the Sino–African education cooperation and exchange, published between 2005 and 2022.

The methodology used in this paper is qualitative in nature with a thematic approach. The author used content analysis techniques to spotlight the major themes of the topic studied. The author selected the papers and theses, based on their heuristic capacity, from two major databases for the English and Chinese literature: Web of Science and CNKI. The selection process resulted in 60 high-quality peer-reviewed articles and theses. Another 30 research articles and theses were used as supplementary resources.

The literature concentrates on six points: the historical development, the nature of the exchange, the frameworks of the cooperation, vocational training and knowledge transfer, African students in China and their experiences, and education cooperation and soft power. However, research tends to be somewhat polemical rather than an academic debate between Chinese researchers and their western peers. Therefore, empirical studies beyond the geopolitical preoccupations and the “YEA” or “NAY” to the Sino–African education exchange are critically needed.

The implications of this study go beyond the east/west or developed/developing world rhetoric and focus more on sustainable educational development on a global scale. Understanding how the literature on the Sino–African education engagement is shaping, provides valuable insights into international education in the global south. It can also be implied to approach educational engagement with other destinations such as India, Türkiye and Brazil.

This thematic literature review concentrates on the educational aspect of Sino–African relations. It compares English and Chinese peer-reviewed scholarly articles and theses on China–Africa educational engagement and has heuristic implications for sustainable educational development globally.