This article reviews recent developments in fluid power engineering, particularly its market and research in China. The development and new techniques of the pump, valve, and actuator are presented in brief with a discussion of two typical modern fluid power systems, which are the switched inertance hydraulic system and the hydraulic quadruped robot. Challenges and recommendations are given in four aspects including efficiency, compactness and integration, cleanliness, and fluid power education.

Running conditions for piston pin boss bearing have become very severe due to the high combustion pressure and piston temperature increase over the past ten years. The aim of this paper was to analyze the friction and lubrication characteristic of piston pin boss bearings and a connecting rod small end bearing. This paper provided a comprehensive analysis of piston pin based on a multi-body dynamic model which considers the oil film cavitation and structure deformation. Effects of different lubrication models, pin structures, and thermal deformation on the lubrication were discussed. The lubrication characteristics and performance parameters including oil film pressure distribution, asperity contact pressure, the minimum oil film thickness, the maximum oil film pressure, and friction power loss were listed. The results showed that the minimum oil film thickness was very different and the maximum oil film pressure was nearly the same. A parabola profile of pin bore can reduce the wear to some extent, and a flare profile intensified wear in some places and caused the wear to be concentrated on a smaller area. Reducing the inner diameters will reduce the wear of the pin boss. However, in a realistic design of the pin, avoiding high inertial force of the piston system and satisfying the demand for reliability of the pin, increasing the inner diameters and reliability is a ‘trade off’ problem. A suitable design of the hollow diameter is very important. The results can provide guidance for the design of the pin boss bearing.

The problem of optimal sensor placement plays a key role in the success of structural health monitoring (SHM) systems. In this study, a new method is presented to investigate the optimization problem of sensor placement on gantry crane structures. The method is a combination of an improved harmony search (HS) algorithm and the modal assurance criterion (MAC). Firstly, we review previous studies on setting reasonable values for HS parameters that have the most impact on the result, and highlight the lack of general rules governing this aspect. Based on more efficient HS algorithms resulting from those studies, we apply our proposed technique to the optimization problem of sensor placement on gantry crane structures. The purpose of the optimization method is to select the optimal sensor locations on gantry crane girders to establish a sensor network for an SHM system. Our results show that the HS algorithm is a powerful search and optimization technique that can lead to a better solution to the problem of engineering optimization. The mode of a crane structure could be identified more easily when different mode shape orientations are considered comprehensively.

A numerical study has been carried out for a laminar steady mixed convection flow in a 2D triangular enclosure with an inner rotating coaxial cylinder, with the enclosure filled with ethylene glycol-silicon carbide (SiC-EG). The thermal conductivity and viscosity of the SiC-EG nanofluids were experimentally determined by using a Decagon Devices KD2 Pro thermal property meter and a rotational Brookfield viscometer, respectively. Various pertinent parameters, such as the dimensionless rotation velocity, solid volume fraction, dimensionless radius of the inner cylinder, and Rayleigh numbers, were analyzed to determine their influences on heat transfer and fluid flow. Results clearly show how the direction of rotation of the cylinder affects the thermal performance in a triangular enclosure. It is found that the average Nusselt number increases with rise in the Rayleigh number or as more nanoparticles are added to the base liquid. It was also observed that at constant Rayleigh number, different rotational conditions have remarkable effects on the flow and heat transfer characteristics.

Hydrogen as a clean, efficient, and sustainable energy has attracted considerable attention in recent years. Hydrogen production from aqueous-phase reforming (APR) of biomass-derived alcohols is preferable to other methods because of its wide renewable resource, mild reaction conditions, and low processing cost. In this paper, the progress in the APR process of different biomass-derived alcohols for H₂ production is reviewed, and the reaction mechanisms are briefly discussed for different catalysts. Pt-based catalysts exhibit high H₂ selectivity but low conversion of the alcohols. Ni-based catalysts exhibit high activity and conversion but low H₂ selectivity and yield.

As Morris et al. (2013) indicated ‘it is a very good idea to have a policy in place for dealing with these [ethical] issues’, and based on the ethical code and flowcharts of the Committee on Publication Ethics (COPE) and our experience at Journals of Zhejiang University-SCIENCE A/B & FITEE, we have posted the 2015 JZUS-policy online (http://www.zju.edu.cn/jzus/Policy.php). It includes three sections: Forms of Plagiarism, Anti-Plagiarism Policy, and CrossCheck Workflow. The following is the full text of this policy.