Previous work concerning ocean compressed air energy storage (OCAES) systems has revealed the need for an efficient means for compressing air that minimizes the energy lost to heat during the compression process. In this paper, we present analysis, simulation, and testing of a tabletop proof-of-concept experiment of a liquid piston compression system coupled with a simulated OCAES system, with special attention given to heat transfer issues. An experimental model of a liquid piston system was built and tested with two different materials, polycarbonate and aluminum alloy, used for the compression chamber. This tabletop liquid piston system was tested in conjunction with a simulated OCAES system, which consisted of a hydrostatic tank connected to a compressed-air source from the wall to mimic the constant hydrostatic pressure at ocean depth experienced by the air stored in an actual OCAES system. Good agreement was found between the experimental and numerical studies and demonstrated that the heat transfer characteristics of a liquid piston compression process are effective in reducing the increase in air temperature that occurs during the compression process. The results also suggest that it may be possible to achieve a near-isothermal process with a fully optimized liquid piston compression system.

The defects of the lower tooth height and of larger pitch in thread portion of rolled pieces are prone to appearing when rolling thread shaft in cross wedge rolling. To solve this problem, changing the blank shape and size were tried. Two types of concave conical and round blanks are designed with concave conical blanks obtained by rolling in the cross wedge rolling. Because the design of the rolling die is simple, good precision of blank can be ensured. Multiple size types of blanks were designed and the rolling experiment was made in the rolling mill of model H630. By measuring the values of the tooth height and pitch, the effect of blank shape on thread shafts rolled in the wedge rolling were investigated carefully. The reasonable size range of the blank shape was obtained. The conclusions above pave the theoretical foundation for the in-depth study on this technology.

The yaw rock-breaking processes of roadheader single pick at different positions have been simulated by using LS-DYNA, and the dynamic process that pick-shaped cutters cut hard-rock has been analyzed with the technique of SPH(Smooth Particle Hydrodynamics). It has been found that separating rock into smooth particle hydrodynamics(SPH) units can effectively simulate and analyze deformation, damage and other phenomena of rock to lay a foundation of pick design, processing and failure modes analysis. The results of calculations show that this kind of new algorithm is feasible and effective to simulate rock penetration and pick mechanics problems.

In order to reach and test the surface defects on industrial parts, based on Machine Vision this paper put forward a defective parts detection method. The method of median filter was adopted to eliminate the noise of image. The Ostu-method was used for the segmenting threshold. Pixel level and level edge detection were used to complete the precise components defects detection. Experiments show that this scheme is feasible, and can achieve high accuracy and shorter testing time.

He X, Ma ZY, Feng C, Shao WZ. Approach to compositing multiple model transformation techniques.