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The purpose of this study is to investigate the effects of load and rotation speed on dry sliding of silicon nitride, including a series of tribological behaviors (friction coefficient, wear rate, temperature rise, etc.) and wear mechanism. Through the analysis of the above characteristics, the influence law of load and speed on them and the internal relationship between them are determined, and then the best comprehensive performance parameters of silicon nitride full-ceramic spherical plain bearings in dry sliding are predicted, which can provide guidance for the operation condition of silicon nitride full-ceramic spherical plain bearings in dry sliding.

The experimental study of different loads and rotation speeds under dry friction conditions was carried out by the using ball-disk sliding test method.

With the increase of load, the friction coefficient of silicon nitride friction pair and the wear rate of silicon nitride ball decrease continuously. With the increase of rotation speed, the friction coefficient of silicon nitride friction pair first increases and then decreases, and the wear of silicon nitride ball first increases and then decreases. With the increase of load and rotation speed, the wear mechanism eventually changes to adhesive wear.

Because of the low timeliness and inefficiency of bearing experiments, this work adopts a simple ball-disk model to comprehensively explore the influence rules of different conditions, which provides a theoretical basis for the subsequent practical application of silicon nitride full-ceramic spherical plain bearings.

The study aims to the distribution rule of lubricating oil film of full ceramic ball bearing and improve its performance and life.

The paper established an analysis model based on the fluid–solid conjugate heat transfer theory for full ceramic ball bearings. The distribution of flow, temperature and pressure field of bearings under variable working conditions is analyzed. Meanwhile, the mathematical model of elastohydrodynamic lubrication (EHL) of full ceramic ball bearings is established. The numerical analysis is used to study the influence of variable working conditions on the lubricant film thickness and pressure distribution of bearings. The temperature rise test of full ceramic ball bearing under oil lubrication was carried out to verify the correctness of simulation results.

As the speed increased, the oil volume fraction in full ceramic ball bearing decreased and the surface pressure of rolling element increased. The temperature rise of full ceramic ball bearings increases with increasing speed and load. The lubricant film thickness of full ceramic ball bearing is positively correlated with speed and negatively correlated with load. The pressure of lubricating film is positively correlated with speed and load. The test shows that the higher inner ring speed and radial load, the higher the steady-state temperature rise of full ceramic ball bearing. The test results are in high agreement with simulation results.

Based on the fluid–solid conjugate heat transfer theory and combined with Reynolds equation, lubricating oil film thickness formula, viscosity temperature and viscosity pressure formula. The thermal analysis model and EHL mathematical model of ceramic ball bearings are established. The flow field, temperature field and pressure field distribution of the full ceramic ball bearing are determined. And the thickness and pressure distribution of lubricating oil film in the contact area of full ceramic ball bearing were determined.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2023-0126/

This study aims to investigate the dynamic characteristics of a high-speed mechanical seal by considering the flow regime, cavitation phenomenon and inertia effect.

Based on the high-speed conditions of a mechanical seal with a low-viscosity fluid, a multi-factor coupled lubrication model of a mechanical seal is established. The perturbation Reynolds equation set is derived using the perturbation method, and the effects of turbulent flow and inertia on sealing performance are discussed.

The results indicate that turbulence significantly influences the dynamic characteristics of low-viscosity fluids under high-speed conditions.

The results of the dynamic characteristics presented in this study are expected to provide guidance for the design of mechanical seals.

The purpose of this paper is to explore the developments in final electricity consumption, estimate the portions of changes that can be attributed to national, sectoral or regional factors, and to investigate determinants of the regional component (RC) in Croatia at the subnational level in the period 2001-2013.

In the first stage, the dynamic shift-share method is used to decompose final electricity consumption, and then, in the second stage, the panel population-averaged logit model is conducted to find the main determinants of the extracted RC.

The results show that both the sectoral factor and the regional factor are responsible for an increase in electricity consumption over the period considered, whereby the regional specificities had a larger impact in general. Thereby, the most developed regions, including the tourism-oriented ones, exhibited the largest average increase in electricity consumption mainly due to positive effects of the regional-specific factors, while the negative effects of these factors were mainly responsible for low average rates of changes in electricity consumption in less developed regions.

The results suggest that regional-specific energy conservation programs might be more effective in improving energy efficiency than the sector-oriented ones, as well as that socio-economic and contextual determinants matter when it comes to the probability of having a positive regional effect on the electricity consumption rate.

The paper investigated the determinants of the extracted RC which has not yet been addressed in the energy economics literature.