Powder wettability is one of the important characteristics in various industrial powder processes. Understanding and modeling the liquid penetration into the powder layer are essential to evaluate the powder wettability. For this purpose, the numerical simulation is a promising approach. However, it has been challenging to effectively simulate the wetting phenomena on complex solid surface such as powder layer. In this paper, as a first step of modeling the wetting of powder layer, a numerical simulation model for the liquid penetration phenomena was developed using the lattice Boltzmann method (LBM) with the free-energy model. Our model was validated by two simple numerical problems. The simulation model was then applied to the system where the meniscus formed at the liquid-liquid interface in circular and square channels. Here, the square channel can be considered as a simplest model for the flow path inside the powder layer. Finally, the liquid penetration phenomena in the two channels were demonstrated.
Currently, in the cosmetics industry, substitution of plastic micro beads (PMB) in pressed foundation (PF) has begun to prevent marine pollution by PMB. Therefore, in order to develop new substitutes, it is important to find the relevance between characteristics of spherical particles for cosmetics and PF feeling in use.
In this study, we developed objective evaluation system for spherical particles by using Small Particle Compressive Strength Analyzer (NS-A100), which have been widely used for the strength analysis of granules in the field of pharmaceutical, food industries and others. Five kinds of spherical particles were selected. As the results, apparent Young’s modulus and pseudo-permanent strain ratio derived from NS-A100 measurement correlated to the soft feels and anti-shock property of PF, respectively. These results indicated that this system can be applied to evaluation of single particle property and estimation of formulation characteristics as well.
Toward industrial applications of commercialized carbon nanotubes (CNT), fully utilizing the intrinsic CNT properties is challenging due to the quality deterioration and the uncontrolled states through dispersion processes in matrices. Therefore we propose a predispersion step of CNTs prior to distributing them into matrices, clarifying the unravelling effect of CNT powders by various liquids with different viscosities like alcohols, silicone oils, ionic liquid, ketone, hydrocarbons, aprotic polar solvents, and water. Regardless of solvent polarity, liquids with higher viscosities led to more unravelled CNT particles, reaching up to an approximately ten thousand times higher particle number than one before the dispersion.
It is required in various field to accurately assess 3D particle characteristics such as particle shape and size distribution. However, 2D characteristics are often measured instead of 3D in practice. A conversion method simultaneously estimating multiple 3D characteristics from measurable 2D counterparts is developed. Briefly, the method consists of the following steps: creation of 3D particle models; computation of 3D and 2D parameter distributions of the particle models; and determination of the optimal combination of the 3D particle models to fit the measured 2D parameter distributions. The method was numerically validated using ellipsoid-based particles with various surface roughness.
The effects of TEMPO-oxidized cellulose nanofiber (TCNF) as an additive on ceramic slip casting process were investigated. Rheological properties of ceramic slurry, formability and sintered body properties were evaluated. By means of the precipitation test and viscosity measurement, development of thixotropic property and improvement of dispersion stability of the slurry were revealed as contents of TCNF increased. The green body formed from TCNF added slurry had excellent demoldability. Well-dispersed TCNF added slurry achieved stable slip cast forming process having excellent mass productivity and dense sintered bodies were obtained as a final product.