Information on interactions between oat β-glucan and tea polyphenols (TP) is not available in the published literatures. Equilibrium dialysis was applied to determine the adsorption of TP into β-glucan, and response surface methodology (RSM) was employed to optimize the absorbing variables (pH, temperature, and phosphate buffered saline (PBS) buffer concentration). The equilibrium data at constant temperature were fitted with the Langmuir, Freundlich, and Redlich-Peterson models. The results showed that the Freundlich model was the best method to describe the experimental data. Parabolic curves were obtained for pH and temperature. In terms of adsorption capacity, factors including temperature, pH/temperature, and buffer concentration/temperature had the greatest influence on the response. The highest adsorption capacity of TP into β-glucan was 134.55 μg mg(-1) at the following optimized conditions: pH 5.56, PBS buffer concentration 0.13 M, and temperature 40 °C. No significant differences (p > 0.05) between the experimental and predicted values confirmed the adequacy of the response surface equations.
Purpose
To improve the lubrication and tribology performance (LTP) of the crankpin bearing, this paper aims to propose the optimization of the crankpin bearing parameters considering effect of the high-speed dynamic load and micro asperity contact.
Design/methodology/approach
A numerical simulation method combined by the slider-crank-mechanism dynamic and lubrication models is applied to solve the dynamic and lubrication equations of crankpin bearing. These equations are then computed via an algorithm program written in Matlab software. The contact force (Wac) in the asperity contact region, friction force (Ff) and friction coefficient (μ) of crankpin bearing are chosen as objective functions. The original parameters and experimental data of the engine are used for the simulation to enhance the reliability of the research results. The parameters are then optimized to obtain the minimum values of Wac, Ff and μ.
Findings
The research results show that the LTP is significantly improved with optimized parameters. Particularly, the maximum values of Wac and Ff are greatly decreased by 27 and 32%, respectively.
Originality/value
Reducing the width, radius and surface roughness and increasing the radial clearance of crankpin bearing can improve better the LTP.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-02-2020-0072/
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