A ball-on-disk tribometer was employed to evaluate the lubrication performance and mechanisms of innovative TiO 2 nano-additive water-based lubricants. Two experimental methods were applied to determine the optimal mass fraction of TiO 2. In the method I, lubricants were added onto the worn disk tracks at a predetermined time interval. In the method II, the disks were immersed in the lubricants continuously during the whole process of tribological tests. The results both indicate that the water-based lubricants can significantly reduce the coefficient of friction (COF). The 0.8 wt% TiO 2 lubricant demonstrates excellent tribological properties including the lowest COF and the strongest wear resistance under all lubrication conditions. The lubrication mechanisms are attributed to the rolling and mending effects of the TiO 2 nanoparticles.

No abstract

Friction and wear characteristics of TiO2 nano-additive water-based lubricant on Friction and wear characteristics of TiO2 nano-additive water-based lubricant on ferritic stainless steel ferritic stainless steel

Graphene oxide (GO) and alumina (Al 2 O 3 ) nanoparticles were added in deionized water in order to synthesise a dimensionally integrated nanolubricant. Tribological tests were performed using an alloy/stainless steel contact pair. A 0.12 wt.% 1:1 GO-Al 2 O 3 lubricant produced 64% and 47% reductions in the COF as well as 63% and 60% improvements in the Ra compared with 0.06 wt.% Al 2 O 3 and 0.06 wt.% GO solutions. Analysis of the worn surface indicated that a thin film consisting of a layer of GO and a tribo-layer of Al 2 O 3 was formed during testing. The GO layer prevented the direct contact of surface asperities, leading to a low resistance to sliding, whilst the Al 2 O 3 tribo-layer acted as a load bearer to strengthen the GO layer.

No abstract

In this study, single-layer graphene oxide (GO) sheets were uniformly dispersed in water, and the effects of pH modification on the structure and morphology of the GO sheet were investigated. The flexible and large GO sheets were broken down and chemically reduced, caused by the increase of pH value from 3.10 to 9.70. The tribological performance of the GO suspensions of different pH values was characterised using a ball-on-three-plate tribometer with a steel on steel contact. It was found that using the GO suspension of pH 3.10, the coefficient of friction (COF) and wear mark radius were reduced by 44.4% and 17.1%, respectively, compared with baseline water, whereas neutral and basic GO suspensions increased COF and wear significantly. The effect of pH value on the lubrication was attributed to morphology change of the GO sheets in suspensions.

No abstract

Diabetes mellitus represents a significant global health threat characterized by hyperglycemia caused by inadequate insulin secretion and/or insulin resistance. Exogenous insulin supplements had been recognized as a crucial treatment for achieving successful glycemic control in patients with Type 1 and most patients with Type 2 diabetes. Over the past century, substantial progress has been made in the development of novel insulin formulations, including the super‐fast‐acting and long‐acting basal insulin analogs, of which the latter is indispensable for the management of nocturnal fasting and intraprandial blood glucose within the normal physiological range. Recently, combining chemical and genetic engineering with drug optimization have resulted in a formidable evolution in ultra‐long‐acting weekly insulin. Here, the current state of once‐weekly insulin analogs and the euglycemic clamp technique used in the early clinical development to elucidate the pharmacokinetics and pharmacodynamics of this type of novel weekly insulin analogs were systematically overviewed.