DEM analysis of cohesive granular shear flow using dynamic adhesion force model – Model validation for contact-dominated regime

Tanaka T., Tanaka S., Washino K., et al. DEM analysis of cohesive granular shear flow using dynamic adhesion force model – Model validation for contact-dominated regime. Powder Technology 447, 120198 (2024); https://doi.org/10.1016/j.powtec.2024.120198.When the DEM simulations are performed, the particle stiffness of the Discrete Element Method (DEM) is often reduced to reduce the computational cost. The Dynamic Adhesion/Cohesion Force Model (DAFM/DCFM) was proposed for adhesive/cohesive particles to make the effect of adhesion/cohesion force on the collisional motion of a particle with a reduced particle stiffness equivalent to that of the original system. This study validates the applicability of DCFM to the contact-dominated regime by means of a series of DEM simulations of two-dimensional simple shear flow of cohesive spherical particles. The results demonstrate that DCFM accurately represents the cohesive nature of the original system with respect to the fluid-to-solid phase transition of granular medium due to a reduction in shear rate, as well as the shear stress of the granular medium. It is demonstrated that the bond-breaking model proposed in the present study describes well the validity of DCFM in the contact-dominated regime

Coarse grained DEM simulation of non-spherical and poly-dispersed particles using Scaled-Up Particle (SUP) model

In this work, the validity of the Scaled-Up Particle (SUP) model, which is a novel coarse grain model for Discrete Element Method (DEM), is examined to simulate a flow of non-spherical and poly-dispersed particles. The SUP model is based on the authors’ previous work and the scaling law is derived from the continuum assumption of an arbitrary particles flow. We discuss that the model is applicable not only to spherical and mono-dispersed particles, as is the case tested in the previous work, but also to non-spherical and poly-dispersed particles. Simulations of various systems are performed such as compression of a particle bed, heap formation, high shear mixer, large scale rotary drum and V-mixer. It is shown that the results obtained from the SUP model are in both qualitative and quantitative agreement with those from the original particles as long as the resolution is sufficiently high.Washino K., Chan E.L., Nishida Y., et al. Coarse grained DEM simulation of non-spherical and poly-dispersed particles using Scaled-Up Particle (SUP) model. Powder Technology 426, 118676 (2023); https://doi.org/10.1016/j.powtec.2023.118676

大学生の食事に対する意識と1 日の献立モデル

University students should start to manage their dietary habits. In this paper, university student attitudes toward dietary habits and self-catering were studied. The first factor which students in general considered was price, followed by desired taste and volume. Many home students did not cook for themselves but board students often cooked. Students did not cook when they bothered about cooking, had no time, and were tired. But they did not dislike cooking. Guidelines for diet were obtained from 70% of students. Based on these results, we made a model menu of "normal diet" for one day

Changes in biotin levels during production of natto, Japanese fermented soybean

The change of biotin level during production of natto (Japanese fermented soybean) was investigated in this study.  The total biotin level was measured by an agar plate bioassay using Lactobacillus plantarum ATCC 8014.  The total biotin level decreased during water soaking, but increased after the fermentation of soybeans using Bacillus subtilis var. natto (B. natto) and reached a maximum level.  The increase of total biotin was not affected by Asp, Arg, and Ile which promoted the growth of L. plantarum in high concentrations.  The peak level of biotin in the fermented soybeans was significantly higher than that of dry soybeans.  The fermented soybeans at the biotin peak level were adequate for food.  In addition, we detected 9 and 4 biotinylated polypeptides in the soybeans and B. natto used in this study, respectively.  We speculated that the increase of biotin level may depend on the increase of the 4 biotinylated polypeptides and free biotin in B. natto