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A New Star-Like SurfaceTexture for Enhanced Hydrodynamic Lubrication Performance

Uddin M. S., Liu Y. W., Shankar S.

Archives of Metallurgy and Materials

2017

Vol. 62, iss. 3

1863--1869

This paper presents a numerical modelling and optimization of a new ‘star-like’ geometric texture shape with an aim to improve tribological performance. Initial studies showed that the triangle effect is the most dominant in reducing the friction. Motivated with this, a ‘star-like’ texture shape consisting of a series of triangular spikes around the centre of the texture is proposed. It is hypothesised that by increasing the triangular effect on a texture shape, the converging micro-wedge effect is expected to increase, hence increasing the film pressure and reducing the friction. Using the well-known Reynolds boundary conditions, numerical modelling of surface texturing is implemented via finite difference method. Simulation results showed that the number of apex points of the new ‘star-like’ texture has a significant effect on the film pressure and the friction coefficient. A 6-pointed texture at a texture density of 0.4 is shown to be the optimum shape. The new optimum star-like texture reduces the friction coefficient by 80%, 64.39%, 19.32% and 16.14%, as compared to ellipse, chevron, triangle and circle, respectively. This indicates the potential benefit of the proposed new shape in further enhancing the hydrodynamic lubrication performance of slider bearing contacts.

Synthesis of spherical macroporous epoxy-tetraethylenepentamine chelating resin for preconcentration and separation of trace noble metal ions

Yang D., Chang X.-J., Wang S., Liu Y. W.

Chemia Analityczna

2005

Vol. 50, No. 4

685-694

A new spherical macroporous epoxy-tetraethylenepentamine chelating resin was synthesized from epoxy resin simply and rapidly. Its adsorption-desorption properties were studied in detail. Au(I[l), Pt(IV) and Pd(IV) was quantitatively adsorbed on the resin from aqueous solutions of pH = 2.0-4.0. Adsorption capacities of the resin towards Au(III), Pt(IV) and Pd(IV) were 8.9 x 10-4, 7.6 x 10-4, and 9.6 x 10-4 mol per gram of the epoxytetraethylenepentamine chelating resin, respectively. The adsorbed metal ions were nextdesorbed at 50-60°C using 3% thiourea solution in 2 mol L-1 HCI. Other metal ions caused little interference during preconcentration and simultaneous determination ofAu(IIl). Pt(IV) and Pd(IV) by ICP-AES. Au(III), Pt(IV) and Pd(IV) could be determined at the co

Opisano prostą i szybką metodę syntezy z żywicy epoksydowej kulistego, makroporowatego jonitu chelatującego epoksy-tetraetylenopentaarninowego. Zbadano szczegółowo jego własności adsorpcyjno-desorpcyjne. Au(III), Pt(IV) i Pd(IV) były ilościowo zatrzymywane na jonicie z roztworów wodnych o pH = 2.0r4.0. Pojemności adsorpcyjne jonitu w stosunku do Au(III), Pt(IV) i Pd(IV) wynosiły odpowiednio: 8.9 x l 0-4, 7.6 x l 0-4 i 9.6 5 10-4 mol na gram jonitu. Zatrzymane jony desorbowano w temp. 50-60°C za pomocą 3% roztworu tiomocznika w 2 mol L-4 HCI. Inne jony miały mały wpływ na przebieg zatężania i jednoczesnego oznaczania Au(III), Pt(IV) i Pd(IV) za pomocą ICP-AES. Możliwe było oznaczenie Au(III), Pt(IV) i Pd(IV) nawet na poziomie stężeń l ng mL-1 przy stopniu zatężenia równym 300.