Investigation on tribological behaviors of MoS2 and WS2 quantum dots as lubricant additives in ionic liquids under severe conditions

Despite excellent tribological behaviors of ionic liquids (ILs) as lubricating oils, their friction-reducing and anti-wear properties must be improved when they are used under severe conditions. There are only a few reports exploring additives for ILs. Here, MoS2 and WS2 quantum dots (QDs, with particle size less than 10 nm) are prepared via a facile green technique, and they are dispersed in 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIm]PF6), forming homogeneous dispersions exhibiting long-term stabilities. Tribological test results indicate that the addition of MoS2 and WS2 QDs in the IL can significantly enhance the friction-reducing and anti-wear abilities of the neat IL under a constant load of 500 N and a temperature of 150 °C. The exceptional tribological properties of these additives in the IL are ascribed to the formation of protective films, which are produced not only by the physical absorption of MoS2 and WS2 QDs at the steel/steel contact surfaces, but also by the tribochemical reaction between MoS2 or WS2 and the iron atoms/iron oxide species.

Treatment Analysis of Limb Fractures Combined with Traumatic Shock

Objective:To evaluate the treatment regimen and efficacy for limb fractures combined with traumatic shock(TS).Methods:A total of 88 patients with limb fractures combined with TS,admitted between January 2021 and December 2023,were selected.Patients were divided randomly using a numerical grouping method.The observation group underwent restricted fluid resuscitation combined with comprehensive treatment,while the reference group received conventional fluid resuscitation combined with comprehensive treatment.Recovery time,fracture prognosis,complications,severity of the condition,and post-fracture joint function were compared between the two groups.Results:The observation group showed shorter symptom recovery times,a higher rate of anatomical fracture reduction,and a lower complication rate compared to the reference group(P<0.05).After one week of treatment,the severity score of the condition in the observation group was lower than that of the reference group,and all joint function scores were higher in the observation group(P<0.05).Conclusion:Restricted fluid resuscitation combined with comprehensive treatment for limb fractures with TS can alleviate symptoms,improve fracture prognosis,reduce related complications,decrease the severity of trauma,and enhance joint function.The therapeutic effect is excellent.

Thermal analysis of lubricated three-dimensional contact bodies considering interface roughness

Surface roughness and thermal action are of remarkable importance in the lubrication performance of mechanical components,especially in extreme conditions.However,available studies mainly focus on the full-film lubrication conditions without considering temperature rise and real 3D surface roughness due to the complexity of surface topography and temperature characteristics.Moreover,studies on the interfacial thermal behaviors of 3D rough surface lubricated contact in an extended range of working conditions remain limited.In this paper,a deterministic mixed thermal elastohydrodynamic lubrication model considering real 3D surface roughness and thermal effects is proposed.In this model,pressure and temperature are coupled with each other,the computation of elastic deformation is accelerated through the discrete convolution and fast Fourier transform method,the temperature field is calculated with the column sweeping technique,and the semi-system method is introduced to improve convergence and numerical stability under severe conditions.The model is validated by comparing its results with available published numerical and experimental results.The thermal behaviors of the contact interface are studied in a wide range of working conditions.The influences of surface roughness and thermal effect on lubrication performance are revealed.The results show that the proposed model can be used as a powerful analysis tool for lubrication performance and temperature prediction in various heavy-load,high-speed lubricated components over a wide range of lubrication conditions.