Si-Wei Zhang

Tribological Behaviours of Wax-in-Oil Gel Deposition in Orthogonal Cleaning Process

Tribological behaviour of wax-in-oil gel deposition at orthogonal cleaning process has been directly observed with a custom-built experimental setup. Experimental results show that the chip formation of wax scraping is due to rubber tribology of elastomer disc. The scraping chip instability arises from a competition between scraping forces and the adhesion forces. An analysis of debris-material removal rate in wax scraping with negative rake face has been carried out. The study has also shown that the wax-scraping force component is sensitive to rake angle, which may be used as primary basis for developing wax-removal estimating strategies. Flank face wear results in a substantial increase in the wax-scraping force, which should be incorporated into the wax-cleaning efficiency predictive model. The behaviours of the residual phenomenon depend on the inlet aggregation in orthogonal wax-cleaning process.

Frictional behaviors of rough soft contact on wet and dry pipeline surfaces：With application to deepwater pipelaying

Elastic rubbers are widely used in nature and engineering. In order to better understand soft rough contact under dry and wet conditions during deepwater pipelaying process, various polyurethane (PU) discs both in PU-pipe and PU-steel sliding combinations have been investigated by using self-developed tribometer. The tribological test results show that the friction coefficient can be clearly seen: PU90< PU80 < PU70, under dry conditions. Experimental results also indicate that the two dramatic increases of the frictional coefficient exist in the rough soft PU-pipe contact. The potential influence of asperities and thin liquid film is discussed.

Synthesis and tribological properties of CuS/ZnS nanoparticles doped polyelectrolyte multilayers

Abstract Polyelectrolyte multilayer thin films [poly(diallyl dimethylammonium chloride) (PDDA) and poly(acrylic acid) (PAA)] for the synthesis of CuS and ZnS nanoparticles were prepared. The CuS/ZnS nanoparticles in situ synthesised by immersing the PDDA/PAA polyelectrolyte multilayer thin films into Cu2+(or Zn2+) and Na2S aqueous solutions alternately, which were characterised in detail by UV visible absorption spectroscopy, atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) analysis. The CuS and ZnS nanoparticles doped polyelectrolyte multilayer thin films were synthesised by the layer-by-layer molecular deposition technology and in situ synthesis method. The coefficient of friction (COF) decreased with the in situ synthesis CuS and ZnS nanoparticles doped into the polyelectrolyte layers. The in situ nanoparticles exhibited enhanced wear resistance performance of the plain polyelectrolyte multilayers.