Sessile organisms cause significant economic losses on submerged artificial surfaces such as ships. The use of tributyltin (TBT)-based antifouling paint for underwater ship hulls was banned due to its high toxicity to marine organisms. Therefore, it is necessary to develop low environmental impact antifouling technologies. Previously, antifouling studies focusing on the physiological and ecological understanding of fouling organisms has been conducted. And antifouling materials inspired by surface properties of marine organisms were developed in recent years. This review introduces the settlement selectivity and behavior of barnacle cypris larvae on the surfaces with different surface properties, such as micro-structures and functional groups.

Powder compression is the process of obtaining pellets by directly applying pressure to powder beds. The densification phenomenon involving the plastic deformation of particles is still unclear. In this study, the powder compression process of the binary mixture of powder with different plasticity was calculated by using the discrete element method incorporating Edinburgh elasto-plastic adhesion model. The macroscopic and microscopic powder properties were evaluated in the conditions of different volume fraction plastic powders. The calculation method of contact plasticity between elastic and plastic particles, which was proposed in this study, was validated by the data of experimental comparison tests. The result of this study indicated that particle plasticity strongly affected the powder properties, especially contact area inside the powder bed. We hope that this study will be useful for applications where the contact area inside the powder bed is important, such as batteries.

Using a horizontal batch dry bead mill newly developed by our company, talc raw material was ground in air, and its grinding performance and mechanochemical effect on the sample were evaluated from various perspectives. First, the average diameter of the ground product as a grinding performance decreases with the increase in grinding time or power source unit, reaching the submicron size. In addition, when mill operation is continued, talc changes fine particle aggregation and crystal structure change due to mechanochemical effects, and the phenomenon of detachment of the (OH) group around Mg in the crystals becomes remarkable. The flowability of the ground product is inhibited by the withdrawal of (OH) from the talc crystal, but this flowability is restored when it is dried. When the power source unit in the grinding approaches 3 kWh/kg, it asymptotes to the maximum value of 9% in the weight reduction percentage.

Wet granules are used in various areas, owing to their higher compressibility. In this study, finite element method (FEM) simulations of wet granule compression are performed to discuss the influence of binder on the compressibility of wet granules. The Drucker-Prager Cap model was applied to wet granules with parameters obtained from compression and powder shear tests, and the FEM simulation was performed using these parameters. The results showed that the axial stress at the bottom surface and the radial stress of the wall obtained from the FEM simulation were consistent with the experimental values for the bottom and radial (wall) stress of the compression cell in large strain regions. Furthermore, the FEM results for wet granules with different amounts of binder suggested that particles in wet granules with higher amounts of binder adhered each other more strongly, thereby increasing the axial and radial stresses.

Continuous wet granulation using a twin-screw granulator has attracted much interest in the pharmaceutical industry. The physical properties of granules prepared through the twin-screw granulation process depend on the several factors, such as screw and barrel geometries, operating conditions, and formulations of raw materials. In particular, it is known that the fill level in a twin-screw granulator and the binder additive ratio have an impact on the twin-screw granulation process. In this study, mutual effects of the two major factors on the granulation process was investigated experimentally and numerically. By combining the experimental and numerical analyses, a prediction model of the granule growth rate was proposed. The proposed model demonstrated that the granule growth rate was determined by the total energies (compressive and shear directions) and the index of granulation.