Shotaro Kawakami

Simultaneous Estimation and Modeling of Thermophysical Properties of Big-Eyed Tuna and Pacific Cod

The thermophysical properties (thermal conductivity, thermal diffusivity, and specific heat) of big-eyed tuna and pacific cod were measured at various temperatures (5–50°C) by the modified version of current probe method. The optimal prediction models for these thermophysical properties were determined. The random model was applied to predict the thermal conductivity of seafood in a wide range of temperature and it provided the accurate predictions for the samples. The thermal diffusivities of the samples could be predicted by Martens’s equation. An additive relationship exists between the specific heat of the sample, the composition, and the specific heat of each component.

Discrete Element Analysis of Micro-mechanical Behaviour of a Grain Assembly in Constant Load Direct Shear

Two-dimensional shear box test using vinyl chloride cylinders and vinyl chloride elliptical cylinders and three-dimensional test using brown rice and nylon spheres were performed. The macroscopic shear behaviour of a brown rice assembly had similarities to an elliptical cylinder assembly. The results of two-dimensional discrete element (DE) simulation using circular particles and experiment using the cylinders were in good agreement with the macroscopic shear behaviour of the bulk. As a result of this validation microscopic shear behaviours were analyzed using the DE model. There was a good correlation between the shear force totaled normal force acting on the side wall of the upper box and the sum of contact force in the box. An average angle formed by a contact force vector between particles in the box was close to the simulated internal friction angle. The rotation of maximum principal stress axis in the bed during shearing was suggested by few sliding particles and rotation of principal axis of fabric tensor. The rotation of principal stress axis caused the development of induced anisotropy in the granular media.