In recent years, on the problem of environmental pollution caused by suspended garbage in coasts and bays, sedimented sludge and milliplastics have a serious impact on the environment. In particular, hypoxia caused by eutrophication in the bay is a factor that deteriorates aquaculture productivity. In this study, we developed a helical pump driven by a floating vertical axis wind turbine that can be moored and towed by a ship, and proposed a method of removing the slurried volume of sediment from the sea floor by removing it. Therefore, we report the results of an experiment to investigate the pumping performance of the helical screw pump with respect to the suction capacity.

  Recently, the volume of foreign trash, especially expanded polystyrene, which is travelling across the sea, is increasing. In the ceramic kiln industry, commercial grade LPG is generally employed as a gaseous fuel and simply used as a heat source. It is therefore very useful and necessary to replace a part of gaseous LPG with an alternative fuel, such as polystyrene powder, from the view-point of energy saving. The proposed burner is designed to burn polystyrene powder as an auxiliary fuel with, gaseous propane being employed as a main fuel. In our experiment, we have produced devices that are auxiliary, but essential to the construction and dimensions of the ceramic burner in consideration of the fusible nature of polystyrene powder. They are intended, not only to prevent polystyrene powder from melting in the supply pipe, but also to stop dissolved polystyrene from adhering to the burner wall. By varying the equivalence ratio of the entire combustor, combustion behaviors of the proposed ceramic burner are examined and analyzed experimentally, based on both optical observations of flames, and measurements of temperature and residual oxygen concentration at the exit of the model furnace.

Surface texturing is known as one of approaches to improve the lubrication characteristics of sliding surface. These lubrication characteristics vary depending on the shape, size and the placement of surface texturing. There are several studies on the lubrication characteristics of texturing surface during sliding movement of reciprocating machines. However, researchers are yet to clarify these characteristics when surface texturing is applied to a slider having a curvature. The purpose of this study is to develop optimum design guidelines for surface texturing by clarifying the effect of surface texturing on lubrication characteristics during reciprocating motion. To this end, we have focused on the placement of surface texturing to reduce friction loss in reciprocating motion. Numerical analysis has been performed under three different texturing placements by solving the Reynolds equation using the finite element method to evaluate the effect of surface texturing – (1) one of texturing placement was applied to the entire analysis area: (2) another was applied only to the center of the analysis area: (3) the other was applied only to both ends of the analysis area. The results found that friction loss was most reduced in the third case. Furthermore, when conducting a similar analysis with changing a distance between the two separated textures, we have been able to identify an optimal distance to reduce friction loss when applying surface texturing.