Oscillatory zoning (OZ) is an example of internal composite patterns of materials. It has been reported that microparticles with OZ are obtained by a simple reaction-diffusion system. The two species of cations (Ba²⁺ and Sr²⁺) diffuse into a gel, while a reactive anion (SO₄²⁻) diffuses from the opposite side. After several days, OZ particles are prepared in a resultant precipitation band in the gel. Our goal is the clarification of detailed formation mechanism of such OZ particles and the control of the internal patterns of microparticles for practical applications. In this study, we examine the effect of ionic species on the resultant particles with various combinations of cations (Ba²⁺, Sr²⁺, Mg²⁺, and Ca²⁺) and anions (SO₄²⁻ and CO₃²⁻). As a result, we found that OZ particles, core-shell (CS) particles, or particles with homogeneous composition are prepared depending on the combinations.

Hexagonal boron nitride (h-BN) as laminated layered particle was exfoliated with a wet-rotating disc milling process by changing various process conditions, such as rotating speed, disc clearance, solids loading, flow rate and flow pass. The particle size distribution showed that the lateral size of h-BN particles milled by wet-rotating disc milling was depended on the flow rate and solids loading, and was relatively as similar as that of raw h-BN particles with controlling the process conditions of wet-rotating disc milling. Furthermore, the sedimentation test of milled h-BN particles indicated that the sedimented cake height ratio of milled h-BN particles was higher with increasing the rotating speed and flow pass and decreasing the disc clearance. Also, thickness of h-BN particles was decreased with increasing the sedimented cake height ratio. These various evaluations indicated that the wet-rotating disc milling led to exfoliation of h-BN particles effectively.

Wet-type jet milling (WJM) process was utilized to delaminate two kinds of two-dimensional (2D) nanofillers: hexagonal boron nitride (hBN) and graphite. Poly(dimethylsiloxane)s (PDMS) with different dynamic viscosities from 1 to 1,000 mm²/s were employed as process media in order to study the effect of medium viscosity on delamination behavior. Change in particle shape was followed by evaluating both particle width and thickness from image analysis of SEM images. Sedimentation behavior of the slurries was also studied. It was found delamination of 2D nanofillers was induced by WJM treatment in the low viscosity PDMS. On the contrary, the treatment in high viscosity PDMS was ineffective in delamination of 2D nanofillers. Significant increase of equilibrium sedimentation height was observed for hBN slurry treated in low viscosity PDMS. It is considered that both change in primary particle size/shape and aggregation structure contributes to the increase. In the case of graphite, increase of equilibrium sedimentation height was observed even in higher viscosity PDMS, suggesting the importance of aggregation structure.

Electrostatic levitation allows a monitoring of solidification behavior of single levitated microdroplet. In this paper, novel designed slim-type electrodynamic balance (EDB) coupled with the microscope is evaluated. It enabled us in situ observation of internal mixing of microdroplet with sufficient spatial and time resolutions. With this instrument, we directly observed the crystal growth from the micodroplet of inorganic salt such as NaCl, NaBr, NaI, KCl, KBr and KI, respectively. The morphologies of produced crystal particles were divided into three types, 1) rectangular solid crystal for KCl or KBr with high crystallization relative humidity (CRH), 2) multi-crystalline particle with crystal habit for NaCl and KI with medium CRH and 3) hollow particles for NaBr and NaI droplets with low CRH. The morphologies of the produced particles were more strongly influenced by CRH rather than supersaturation.

Lift forces acting on a single particle are numerically investigated when it is flowing in a square microchannel. Specifically, effects of particle size and rotation on the lift forces are examined by numerical simulation. To this end, a Lagrangian particle tracking method is developed that couples the discrete element method with the direct numerical simulation for precise evaluation of the particle-fluid interaction. Thermal fluctuations are also considered in the method. We find that the equilibrium positions of the focused particle shift toward the channel axis as the particle size increases. The thermal fluctuations can affect the lift forces especially at lower Reynolds number. It is also shown that particle rotation considerably affects the lift forces as opposed to previous interpretation of the contribution of rotation to the lift forces.

In this study, the evaluation of flowability of cohesive powder using the test of powder discharge from an orifice by air flow has been examined. The powder used was three kinds of Calcium hydroxide with different particle diameter. The mean particle diameter of an original powder, Ca(OH)₂ -A, is 13.1 μm. Other particle diameters, i.e. Ca(OH)₂ -B and Ca(OH)₂ -C, are 14.1 μm and 2.5 μm respectively. The initial void fraction and the interstitial air pressure have been varied as the experimental conditions. As a result the powder flow of Ca(OH)₂ -C indicated the lowest flowability which was judged from the relationship between the mass flow rate and the average interstitial air pressure. Furthermore, the cohesiveness of Ca(OH)₂ -C which has the smallest particle diameter was the strongest because the ratio of separation force to gravity force was high. In addition, it is inferred that the main factor of the cohesive force was van der Waals force.

Free micro mixer (FMM), a unique machine for the emulsification of non-soluble solutions and the dispersion of coagulated particles, was newly developed. The complicated flow field, which is composed of elongation flow, shear flow and contractile flow, was employed for the emulsification and dispersion. The complicated flow field was realized by the flow through a micro gap generated by the spherical surface of a ball and the supporting wall. The gap size was controlled by the pushing force of the ball toward the wall by a spring and the pressure on the fluid given by a pump. This device has the following unique and very useful features: clogging free; contamination free; temperature rise free; freely rinsing; freely scale-up. Especially the important feature is that the data obtained by a labo-sacle FMM are directly usable as the recipe for the commercial plant FMM without considering about scale-up factor.

For wide-scale use in small electronic devices and other equipment, coin type manganese dioxide lithium primary batteries are required to have high capacity and conductivity. Basically positive electrode material is composed of conductive material, such as carbon black, binder and manganese dioxide. Although reduction of binder amount may enhance conductivity, it causes chip and crack in the positive electrode. One possible way of reducing binder amount is to use expanded graphite with binding ability, instead of using carbon black. However, as expanded graphite shows low density, it is difficult to disperse expanded graphite into pellet. So far, optimization of the granulation conditions has not been well studied.

The aim of this study is to determine optimal granulation process for manufacturing coin type Li primary batteries. Also, coin type Li primary batteries were made by granules prepared under various granulation methods and their battery performance and conduction of positive electrode were evaluated. It was found that granules made by high shear mixer showed better performance of battery and positive electrode. It was because the conductive material received high shear force by the high shear mixer, and binding performance of expanded graphite fully appeared.

Recently chemical reactors are on the way to downsizing and getting continuous in order to be transportable by truck. We have developed a small continuous crystallizer. The apparatus utilizes good micro-mixing ability for crystalization by applying taylor-vortex to reaction cylinder. It has millimeter-order gap between inner cylinder and outer cylinder to avoid obstruction. In addition, the tip of solution port is shaped into conical and discharging port is placed at the end of the cylinder closely. It is helpful for continuous operation with plug flow and stable crystallization. We examined crystallization of sodium chloride, barium sulfate and L-Arginine hydrochloride.

The optimum parameters for grindings by a jet mill is determined by many experiments, changing parameters, such as the feeding speed, the inlet pressure, and measure the particle size distribution of the corrected powder. This process takes long time and work load. To reduce this optimization time, in-line monitoring of the particle size distribution for the jet mill process was investigated. We could successfully monitor the particle size distribution of the ground particles, just after the jet mill process, using an in-line laser diffraction measurement system. A proportional relationship was observed between the supplying speed of the material, and the Volume based median diameter, D_v50 of the ground powder. When we changed the feed rate step by step, we could see the D_v50 value was changed with those steps.