vol.28 (2014)

Bulletin of Research Center for Computing and Multimedia Studies
Vol.28, 2014 ISSN 1882-7694

Thermodynamics and Molecular Dynamic Simulations of Three-phase Equilibrium in Argon (V6)
Yosuke Kataoka, Yuri Yamada
Received: February 4, 2014    PDF    Abstract
Very simplified equations of state (EOS) are proposed for a system involving argon and consisting of a perfect solid and a perfect liquid composed of single spherical molecules in which Lennard–Jones interactions are assumed. Molecular dynamics simulations of this system were performed to determine the temperature and density dependencies of the internal energy and pressure and the supercooled liquid state was also examined. The internal energy and pressure were found to be almost linear as functions of temperature at a fixed volume. The density dependencies of coefficients for pressure and the internal energy are written by linear functions of number density for simplicity and for ease of use.
A study of optimized design of the ∞ eddy current sensor
Hiroki Kikuchihara, Yoshifuru Saito
Received: February 21, 2014    PDF    Abstract
Eddy current testing (ECT) is one of the most representative nondestructive testing methods for metallic materials, parts, structures and so on. Operating principle of ECT is based on the two major properties of magnetic field. One is that alternating magnetic field induces eddy current in all of the conducting materials. Thereby, an input impedance of the magnetic field source, i.e., electric source, depends on the eddy current path. Second is that the magnetic field distribution depends only on the exciting but also the reactive magnetic fields caused by the eddy currents in targets. Former and latter are the impedance sensing and magnetic flux sensing types, respectively. This paper concerns with an optimization of a new magnetic flux sensing type sensor named “∞ coil” whose exciting and sensing coils are composed of the ∞ shape and finite length solenoid coil wound ferrite bar, respectively. Optimization of this ∞ coil fully depends on the 3D finite elements methods. According to the 3D finite element simulation results, we have successfully carried out the optimum size of two exciting coils and a sensing coil.
Thermodynamics of Three-phase Equilibrium in Lennard–Jones System with a Simplified Equation of State
Yosuke Kataoka, Yuri Yamada
Received: February 22, 2014    PDF    Abstract
Simplified equations of state (EOS) are proposed for Lennard–Jones system. This is a model for argon and consisting of single spherical molecules. Molecular dynamics simulations of this system were performed to investigate the temperature and density dependencies of the internal energy and pressure for the gas, liquid, solid, and supercooled liquid states. The internal energy and pressure displayed a near-linear dependency on temperature at a fixed volume. The temperature-dependent term of the average potential energy was assumed to be a linear function of temperature as in the harmonic oscillator.
Application of The Frequency Fluctuation Analysis Method to The Barkhausen Signal and Its Application
Jun KAWAZOE, Yoshifuru SAITO
Received: February 24, 2014    PDF    Abstract
Ferromagnetic materials are widely used for various manufactured products such as cars, trains, and ships. Iron and steel are the most popular materials for frame structures because of their mechanical properties. Nondestructive testing of iron and steel is an extremely practical way of maintaining their mechanical reliability. It is well known that Barkhausen signals are only emitted from ferromagnetic materials while they are magnetizing. These signals also vary depending on their past mechanical as well as radioactive stress histories. In the present paper, we have applied a generalized analysis of frequency fluctuations to Barkhausen signals in order to detect the various mechanical stresses. Surprisingly, we have succeeded in clarifying that application of our frequency fluctuation analysis to the Barkhausen signals made it possible to detect several kinds of different pressure mechanical stresses.
Elasto-Plastic Analytical Method of Condensed Horizontal Stiffness Used for Dynamic Seismic Capacity of RC Structure
Shunya Kaneko, Yohei Hodoshima, Hiroyoshi Komeichi, Nagayuki Yoshida
Received: March 1, 2014    PDF    Abstract
We analyze the real structure of the Ichigaya Tamachi building at Hosei university subjected to the simulated earthquake motion. The newly developed analytical method is used in this research which can evaluate the dynamic seismic capacity of old buildings. This method consists of the multi-mass shear system with condensed horizontal layer stiffness and the observatory data obtained by a microtremor device.
Study on the Characteristics of Distinct Element Method in Soil Test Simulation
Gakuho Morikawa, Kiyotaka Deguchi
Received: March 1, 2014    PDF    Abstract
The purpose of this study is to simulate the direct shear test by using Distinct Element Method (DEM), along with to investigate the characteristics of DEM in this simulation. The conventional shear test simulation using a shear box has a problem on interference between the shear box and test piece particles which causes the disorder in the shear force. To prevent this, the periodic boundary condition and the fixed particle boundary condition are introduced so that the shear box may be eliminated. It is suggested from the results of the analysis, that when simulating direct shear test by DEM, a tangential force interacting between two particles does not have much influence against the peak value of shear stress and the angle of shear resistance. However, the stronger tangential force makes the particle engagement stable and coincidently the noise in the shear stress curve reduce.
Identification of Structural Vibration property by Microtremor Observation
Nonaka Atsushi, Deguchi Kiyotaka
Received: March 8, 2014    PDF    Abstract
The purpose of this study is to present the new process that identifies structural property of the buildings by the microtremor observation. The microtremor observation is said to be effective only in calm environment with little noise such as in late night after closing the buildings. Therefore we use H/V spectrum to delete noises from the observed data, and RD method to identify the natural frequency of the buildings. These methods enable us to find out the exact data even in the day time observation. The proposed methods can also reduce cost and time for the seismic judgment since the detail specification with many workloads is not needed, and effective also in case that the drawings are lost. Additionally, we can know the state of deterioration due to aging or long usage from the elongation of the natural frequency of the buildings.
The Approximate Method to Estimate Potential Evapotranspiration Using Monthly Mean Temperature and Daytime
Haruki Numajiri
Received: March 8, 2014    PDF    Abstract
That in previous studies, there is a high correlation to the integrated value of the monthly mean temperature and integrated value of the monthly potential evapotranspiration by Thornthwaite method is revealed. The monthly mean temperature for 12 months was required for the presumed method of the existing monthly potential evapotranspiration. In this study, the relation between monthly mean temperature and monthly potential evapotranspiration was reanalyzed. The approximating method of monthly potential evapotranspiration not using an annual monthly mean temperature observed value was built using the obtained in result.