The Experts below are selected from a list of 1590 Experts worldwide ranked by ideXlab platform
Jiusheng Li - One of the best experts on this subject based on the ideXlab platform.
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alkyl ethylene amines as effective organic friction modifiers for boundary lubrication regime
Langmuir, 2020Co-Authors: Wenjing Hu, Yanhui Xu, Xiangqiong Zeng, Jiusheng LiAbstract:With the pursuit of fuel economy in the automotive industry, recently Low-Viscosity Lubricant technology has been widely improved. The present work has systematically discussed a series of sulfur- and phosphorus-free organic friction modifiers (FMs) - alkyl-ethylene amines by alkyl-substituted from ethylene amines with various nitrogen atom number and molecular configuration. Herein, the pin-on-flat reciprocation friction tests have exhibited that the addition of the novel alkyl-ethylene amines into base oil leaded to significant reductions in friction coefficient (up to 23 %). Further investigations of tribological properties at elevated temperature demonstrated that the increased number of nitrogen atoms and regular linear atomic arrangement contributed to an improvement of friction reduction (up to 66 %) compared to the neat base oil. Notably, results of water contact angle measurement and infrared spectroscopy (IR) have provided favorable evidences that the novel FMs have adsorbed on the metal surface leading to a formation of tribofilm. Whereby, the tribofilm has prevented the sliding surfaces from direct asperity contact and markedly improved tribological performance from the composition analysis of the worn surfaces by energy dispersive spectrometer (EDS), X-ray photoelectron spectroscopy (XPS) and confocal Raman spectroscopy. Therefore, the present work can provide practical reference for molecular structure design through investigation of structure-performance relations of Lubricant additives.
Xiangqiong Zeng - One of the best experts on this subject based on the ideXlab platform.
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Alkyl-Ethylene Amines as Effective Organic Friction Modifiers for the Boundary Lubrication Regime
Langmuir : the ACS journal of surfaces and colloids, 2020Co-Authors: Xiangqiong ZengAbstract:With the pursuit of fuel economy in the automotive industry, recently Low-Viscosity Lubricant technology has been widely improved. The present work has systematically discussed a series of sulfur- and phosphorus-free organic friction modifiers (FMs)-alkyl-ethylene amines-by alkyl substitution from ethylene amines with various nitrogen-atom numbers and molecular configurations. Herein, the pin-on-flat reciprocation friction tests have exhibited that the addition of the novel alkyl-ethylene amines into base oil led to significant reductions in the friction coefficient (up to 23%). Further investigations of tribological properties at elevated temperatures demonstrated that the increased number of nitrogen atoms and the regular linear atomic arrangement contributed to an improvement of friction reduction (up to 66%) compared to the neat base oil. Notably, results of water contact angle measurement and infrared spectroscopy (IR) have provided favorable evidence that the novel FMs have adsorbed on the metal surface leading to the formation of a tribofilm, whereby the tribofilm prevented the sliding surfaces from direct asperity contact and markedly improved the tribological performance, as seen from the composition analysis of the worn surfaces by an energy-dispersive spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), and confocal Raman spectroscopy. Therefore, the present work can provide a practical reference for molecular structure design through investigation of structure-performance relations of Lubricant additives.
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alkyl ethylene amines as effective organic friction modifiers for boundary lubrication regime
Langmuir, 2020Co-Authors: Wenjing Hu, Yanhui Xu, Xiangqiong Zeng, Jiusheng LiAbstract:With the pursuit of fuel economy in the automotive industry, recently Low-Viscosity Lubricant technology has been widely improved. The present work has systematically discussed a series of sulfur- and phosphorus-free organic friction modifiers (FMs) - alkyl-ethylene amines by alkyl-substituted from ethylene amines with various nitrogen atom number and molecular configuration. Herein, the pin-on-flat reciprocation friction tests have exhibited that the addition of the novel alkyl-ethylene amines into base oil leaded to significant reductions in friction coefficient (up to 23 %). Further investigations of tribological properties at elevated temperature demonstrated that the increased number of nitrogen atoms and regular linear atomic arrangement contributed to an improvement of friction reduction (up to 66 %) compared to the neat base oil. Notably, results of water contact angle measurement and infrared spectroscopy (IR) have provided favorable evidences that the novel FMs have adsorbed on the metal surface leading to a formation of tribofilm. Whereby, the tribofilm has prevented the sliding surfaces from direct asperity contact and markedly improved tribological performance from the composition analysis of the worn surfaces by energy dispersive spectrometer (EDS), X-ray photoelectron spectroscopy (XPS) and confocal Raman spectroscopy. Therefore, the present work can provide practical reference for molecular structure design through investigation of structure-performance relations of Lubricant additives.
Wenjing Hu - One of the best experts on this subject based on the ideXlab platform.
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alkyl ethylene amines as effective organic friction modifiers for boundary lubrication regime
Langmuir, 2020Co-Authors: Wenjing Hu, Yanhui Xu, Xiangqiong Zeng, Jiusheng LiAbstract:With the pursuit of fuel economy in the automotive industry, recently Low-Viscosity Lubricant technology has been widely improved. The present work has systematically discussed a series of sulfur- and phosphorus-free organic friction modifiers (FMs) - alkyl-ethylene amines by alkyl-substituted from ethylene amines with various nitrogen atom number and molecular configuration. Herein, the pin-on-flat reciprocation friction tests have exhibited that the addition of the novel alkyl-ethylene amines into base oil leaded to significant reductions in friction coefficient (up to 23 %). Further investigations of tribological properties at elevated temperature demonstrated that the increased number of nitrogen atoms and regular linear atomic arrangement contributed to an improvement of friction reduction (up to 66 %) compared to the neat base oil. Notably, results of water contact angle measurement and infrared spectroscopy (IR) have provided favorable evidences that the novel FMs have adsorbed on the metal surface leading to a formation of tribofilm. Whereby, the tribofilm has prevented the sliding surfaces from direct asperity contact and markedly improved tribological performance from the composition analysis of the worn surfaces by energy dispersive spectrometer (EDS), X-ray photoelectron spectroscopy (XPS) and confocal Raman spectroscopy. Therefore, the present work can provide practical reference for molecular structure design through investigation of structure-performance relations of Lubricant additives.
Li-li Wang - One of the best experts on this subject based on the ideXlab platform.
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The effect of Viscosity on the cavitation characteristics of high speed sleeve bearing
Journal of Hydrodynamics, 2015Co-Authors: Li-li WangAbstract:The effect of Viscosity on the cavitation characteristics of a high speed sleeve bearing is investigated theoretically and experimentally. The cavitation characteristics, the cavitation shape and the cavitation location of a spiral oil wedge hydrodynamic bearing are investigated experimentally by using the transparent bearing and the high-speed camera. The generalized Reynolds equation is established with considerations of the cavitation mechanism based on the modified Elrod method in theory, and the cavitations of different Viscosity sleeve bearings are analyzed and compared. It is shown that the cavitations are strip-shaped for both the high Viscosity Lubricant and the Low Viscosity Lubricant, and in the rupture region of the oil film at a high speed, the oil vapour or bubbles are produced. With the decrease of the supply pressure and the increase of the rotating speed, the rupture area of the oil film increases distinctly. The cavitation area decreases distinctly and the quality of lubrication is better for the Low Viscosity Lubricant than for the high Viscosity Lubricant. The experiment results in general are consistent with the theoretical results.
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Study and Advance on High Speed Machine Tool Sleeve Bearing with Low Viscosity Lubrication
Proceedings of the 2nd International Conference on Civil Materials and Environmental Sciences, 2015Co-Authors: Li-li Wang, Min WangAbstract:Hybrid sleeve bearings are normally lubricated with high Viscosity Lubricant, the temperature of oil film increases with the increase of rotating speed. The Low Viscosity Lubricant can decrease the temperature, which is the efficient method to increase the rotating speed of hybrid sleeve bearings. A current situation of the published research works on high speed sleeve bearing with Low Viscosity lubrication was summarized. The structure of high speed sleeve bearing with Low Viscosity lubrication was introduced, the effect of wall slip, cavitation, surface roughness, temperature and et al. on bearing properties was analyzed, and the significance of lubrication study for high speed journal bearing with Low Viscosity Lubricant was discussed. Keywords-Low Viscosity, high speed machine tool, key technology.
Virgil Constantinescu - One of the best experts on this subject based on the ideXlab platform.
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Combined thin-film and Navier–Stokes analysis in high Reynolds number lubrication
Tribology International, 2006Co-Authors: Jean Frene, Mihai Arghir, Virgil ConstantinescuAbstract:Abstract The classical theory of hydrodynamic lubrication assumes that the fLow regime is laminar and the inertia forces in the fluid film are negligible. For large bearings using Low Viscosity Lubricant or for high speed, the inertia forces could be important and non laminar fLow occurs. In that presentation a general view of non-laminar lubrication is presented. The different fLow regimes, which occur in bearings and seals, are shown. The theories to obtain the characteristics of bearings operating in turbulent fLow regime are presented. The effects of inertia forces in laminar and in turbulent fLows are shown. Finally results obtained using the complete Navier Stokes equations are presented and it is shown how they are included in the classic lubrication theory.
