Grinding is one of the most basic and important operations of powder processing. Grinding has been carried out all over the world for a long time. However, the grinding mechanism has not been elucidated scientifically. Computer simulation have a possibility to be a useful tool to clarify the grinding mechanism. In this review, new simulation methods for particle breakage were introduced, and the advantage of each method was discussed. Prediction of grinding results based on the impact energy has an advantage of calculation load, however, it is difficult to analyze the grinding process. On the other hand, direct simulation of particle breakage can analyze the grinding process. It is necessary to choose an appropriate method according to the purpose.

In a number of applications of dense gas-solid flows such as fluidized bed and pneumatic conveyer, the size of solid particles is not uniform and a large size difference exists. Because it is strongly related to the system efficiency, the understanding of mixing and dispersion characteristics of the particles in detail is important while it is not trivial due to inherent complexities of phenomena and measurement difficulties in experiments. In this review paper, fundamentals and results of several validation studies of Fictitious particle method (FPM) that is a model extended from Discrete element method-computational fluid dynamics (DEM-CFD) targeting systems with large particle size difference are presented.

12CaO·7Al₂O₃ (so called C12A7) has been known as mayenite, which is a component of alumina cement. As the crystal is composed of positively charged nano-cages, it can clathrate several different anion species and show different outstanding properties, e.g., high oxidizing ability, high conductivity maintaining its optical transparency, catalytic reactivity for producing ammonia from nitrogen and hydrogen gases, etc., depending on the chemical species clathrated in the cates. In the present study, we focus on the newly obtained C12A7 prepared by solution plasma process and examined its phase stability and crystal structures of the unknown C12A7. TEM, XRD, TG-DTA analyses revealed the unknown C12A7 phase has large lattice parameters and small crystallite size compared to the standard (normal) C12A7 phase and is unstable in O₂ containing atmosphere, whereas is stable in H₂ atmosphere.

Periodic structures of colloidal particles have attracted considerable interest because they are promising for a wide range of potential applications. Convective self-assembly of colloidal particles is a possible candidate because it is capable of fabricating ordered arrays in a simple manner at low-cost without any templates. We have succeeded in fabricating stripe pattern parallel to the air-solvent-substrate contact line and dot array pattern by using this technique. In the present study, we newly revealed the formation of stripe patterned structures perpendicular to the contact line by controlling the particle concentration and particle size. We found out that the vertical stripe pattern is formed when the particle size of 500 ‍nm is used under the concentration region between those for the horizontal stripe and dot array patterns. The width of the vertical stripes increases with the particle concentration, while the spacing between stripes remains unchanged against the concentration. Furthermore, we fabricated a peculiar hybrid pattern composed of vertical stripes and dot arrays by using a two-step convective self-assembly method, in which a vertical stripe pattern of 570 ‍nm silica particles was first prepared on a substrate, and the vertical stripe pattern was then immersed in a suspension of 120 ‍nm silica particles.