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In hot rolling, the asperities of oxidised strip and wear debris slide over High Speed Steel (HSS) work roll. Hence, abrasive wear occurs, and wear particles will be removed from the work roll surface. This work introduces a Discrete Element Method (DEM) model which has been applied successfully to study abrasive roll wear of HSS work roll with MC carbides embedded within the oxide layers at 650 °C. From this research, it has been found that the carbide orientation, distribution in the HSS roll, different scratching tip size and scratching depth affect the wear significantly. [ABSTRACT FROM AUTHOR]

The purpose of the study was to assess the safety and effectiveness of conservative surgery for placenta accreta at the Tu Du Hospital in Ho Chi Minh City, Vietnam. From 12/2016 to 12/2017, there were 450 women with placenta previa enrolled to study at high risk pregnancy department of Tu Du hospital, in which 135 cases with placenta accreta were diagnosed by ultrasound. The rate of complications and blood loss during surgery were less than hysterectomy group. [Extracted from the article]

Abstract The influence of molecular structure on adsorption and lubrication of aqueous triblock copolymer on TiO 2 surfaces has been investigated using a realistic MD model. Reference data obtained from DFT calculations have been employed to develop an interaction potential between the copolymer and TiO 2 surface. The results show that R Pluronics form an anchor–buoy–anchor structure absorbed on TiO 2 surface and L Pluronic for buoy–anchor–buoy structure. The shear of tribo-system influences slightly on the orientation of copolymers and non-slip behavior has been observed at solid-fluid interfaces due to the strong adhesion strength of copolymer on rutile surface. The shear viscosity increases with copolymer concentration and molecular chain length. L Pluronic has a lower shear stress than the R ones. Graphical abstract Image 1 Highlights • A new interacting FF between PEO, PPO and TiO 2 surface results in a better prediction of adsorption of copolymer. • The adsorption of copolymer on TiO 2 surface is physisorption with adsorption energy for PPO block larger than PEO. • The adsorption energy per PPO or PEO chain reduces with an increase of surface coverage and in the presence of water. • R Pluronics form an anchor–buoy–anchor structure on the surface while there is a buoy–anchor–buoy one for L types. • The shear affects the orientation of copolymers, and a non-slip behavior has been observed at solid-fluid interfaces. • The shear viscosity increases with the copolymer concentration and chain length. • L Pluronic has a lower shear stress than the R ones. [ABSTRACT FROM AUTHOR]

Molecular dynamics simulations have been carried out to investigate the tribological, structural and rheological properties of thin film hexadecane confined between different iron and iron oxide surfaces. The interfacial slip becomes severe with the increase of loading pressure and shear rate but it is insensitive to temperature. The shear stress increases with the loading pressure whereas the coefficient of friction shows a contrasting propensity. The shear stress and coefficient of friction increase with shear rate; and decrease with higher surface temperature. A logarithmic function has been proposed to correlate the variation of friction with shear rate. The shear viscosity increases exponentially with the loading pressure but this rheological component levels off when the loading pressure exceeds a critical value. [ABSTRACT FROM AUTHOR]