vol.26 (2012)

Bulletin of Research Center for Computing and Multimedia Studies
Vol.26, 2012 ISSN 1882-7594

2-Phase state of Al-Cu alloy
Kubota Kouhei, Yosuke Kataoka
Received: March 1, 2012    PDF    Abstract
Molecular dynamics simulations are performed on an Al-Cu alloy by GEAM (Generalized Embedded Atom Method) molecular interaction function. The number of Al is 648 and that of Cu is 216. The 2-phase state was found between 891 K and 600 K in the cooling process. Liquid part and solid one was observed by molecular configurations.
Thermodynamics on Perfect Solid by Equation of State
Yosuke Kataoka and Yuri Yamada
Received: March 3, 2012    PDF    Abstract
Equation of state on perfect solid is used to obtain thermodynamics properties. Sublimation pressure, isothermal compressibility and expansion coefficient are studied by the equations of state. The results are compared with molecular dynamics simulations.
Vaporization of water by molecular dynamics simulation
Shota Yanagisawa, Yosuke Kataoka
Received: March 5, 2012    PDF   Abstract
Liquid-vapor interface of water is simulated by molecular dynamics. Vapor pressure is obtained by NEV and NTV ensemble simulations. Typical number of molecule in the unit cell is 1300. Average density of the unit cell is close to the observed critical density. Surface tensiondivided by thickness of the interface is also estimated to calculate the temperature where surface vanishes. The calculated results are compared with macroscopic experimental ones.
Phase transition of ice VIII to ice VII by the molecular dynamics simulation
Tomonari Kadowaki, Yosuke Kataoka
Received: March 5, 2012    PDF    Abstract
We investigated the phase transition of ice VIII to ice VII by molecular dynamics simulation. First, the stable structure of ice VIII is prepared at 1 K by NTV ensemble simulation. Under the conditions of constant volume, we calculated the molar potential energy, rotational correlation function, the mean-square displacement at temperature up to 3500 K. The phase transition from ice VIII to ice VII at the T = 540 K is found as a second-order phase transition. The ice VIII has a proton ordered configuration and ice VII has disordered one. The first-order phase transition from ice VII to liquid occurs at T = 2750 K.
Sublimation pressure of solid
Kazuhiro Sato, Yosuke Kataoka
Received: March 5, 2012    PDF    Abstract
Sublimation pressures of rare gases were calculated by thermodynamics. The assumed potential function was Lennard-Jones type. Simple equation of state is derived on FCC solid at low temperatures. The obtained values were compared with the macroscopic experimental values. Oxygen, nitrogen, carbon dioxide, methane and carbon tetrachloride were also studied.
Temperature and density dependence of potential energy and the pressure of Argon
Masahiro Murata, Yosuke Kataoka
Received: March 5, 2012    PDF   
Vapor-liquid phase equilibrium of carbon dioxide
Takato Matsushita, Yosuke Kataoka
Received: March 5, 2012    PDF    Abstract
The vapor-liquid phase equilibrium of carbon dioxide is studied by molecular dynamics simulation. The number of molecule in the unit cell 1100 and NTV ensemble is used. The assumed potential function is Dreiding. The vapor pressure is obtained and compared with the macroscopic data. The surface tension is estimated to see the temperature where the interface vanishes.
Vapor-liquid phase equilibrium of the Lennard Jones system
Kazuma Nishino, Yosuke Kataoka
Received: March 5, 2012    PDF    Abstract
Vapor-liquid phase equilibrium is studied by molecular dynamics simulations on Argon with Lennard-Jones potential. The boiling and critical point are examined by molecular system with liquid-vapor interface. The obtained values of vapor pressure are not so good compared with the macroscopic experimental ones. When the simulation results are reduced with Lennard-Jones parameters, better comparison was obtained on Ne, Ar, Kr and Xe.
Vapor-liquid equilibrium based on van der Waals coefficients determined by the molecular dynamics simulation
Takehiro Haguchi ,Yosuke Kataoka
Received: March 4, 2012    PDF    Abstract
Van der Waals coefficients a and b were determined by molecular dynamics simulation at room temperature and various densities. Molar Gibbs energy was calculated by van der Waals equation of state with the above coefficient a and b. Vapor-liquid equilibrium was obtained from plots of Gibbs energy as functions of pressure at each temperature. Vapor pressure and critical constants were in good agreement with the observed macroscopic experimental results.
Evaluation of Seismic Capacity of the building by Comparing Analysis based on the Drawings with Microtremor Observation
Yuki Fujioka, Shunya Kaneko, Nagayuki Yoshida
Received: March 8, 2012    PDF    Abstract
In this study, considering the vibrational characteristic of a ground and a building, we analyzed Hosei University 58’ building. This study has two processes. The first process consists of the microtremor observation and 3D FEM analysis. In microtremor observation, we examined the natural periods from the vibration data. In the 3D FEM analysis, we calculated several natural periods and investigated the vibrational behavior of the building. Finally, we show the comparison between the observational data and the analytical results. The second process has dynamic response analysis using the shear mass system model. We make the shear mass system model in detail from the drawings of the building. Then inputting seismic waves, we carried out dynamic response analysis by the incremental type method of Runge-Kutta which makes it possible to examine the seismic capacity of the building.
Dynamic Analysis for The Discrete Particle Model by Distinct Element Method ‐Study on Direct Shear Test Simulation‐
Naoto Matsunae, Takahiro Seguro, Nagayuki Yoshida
Received: March 15, 2012    PDF   Abstract
This paper has its main objective on simulating the direct shear test which is one of the indoor soil tests by using Distinct Element Method (DEM). As a sub objective, investigating how the variation of the particle size, the particle shapes and the scale of the test piece cause effects on the shear strength of the test piece. For giving the variation to the particle shape, Combined Distinct Element Method (CDEM) is suggested in this paper, which allows disc elements to be combined rigidly to form irregular shape. From the analysis, it is confirmed that the dilatancy curve of DEM model shows a tendency to distinguish a negative gradient, according to the principle of rotation. This indicates the importance of the shape of element for DEM analysis. Also simplification of the model by a polynomial approximation is effective for estimation of the shear stress. As a result, the direct shear box test is correctly simulated on computer by using DEM. Moreover, the characteristics of the 2-dimensional DEM simulation like a principle of rotation and a shape effect are revealed.
Phase Transition in Perfect Liquid and Perfect Solid
Yosuke Kataoka and Yuri Yamada
Received: March 21, 2012    PDF   Abstract
Equations of state on perfect solid and perfect liquid are used to obtain phase transitions in a system of spherical molecules. How to obtain transition pressure as a function of temperature is shown with an example of worksheet. The program to get transition volume as a function of pressure is also given. Gibbs energy, entropy, volume and expansion coefficient are plotted as functions of temperature at a constant pressure.
Analysis of Shear Wave Field by CIP Method
Soichiro Kanzaki, Yutaka Sasaki, Nagayuki Yoshida
Received: March 21, 2012    PDF   Abstract
When analyzing the wave propagation problem in the infinite or semi-infinite elastic solids, the numerical device which can transmit the outgoing waves is attached to the boundary of the finite analytical region. But, we proposed a new method which combines the CIP method with the finite element method. Its validity is presented by analyzing the rod subjected to the impulse load. And a numerical example for two dimensional ground motion is presented by using the CIP method only and compared with Mathematica.
A Study on Structural Vibration Property Estimated from Microtremor -Structural Identification by Optimization Method-
Kazunari Akimoto and Nagayuki Yoshida
Received: March 24, 2012    PDF   Abstract
This study proposes the identification method based on the dynamic characteristics of the structure, which is measured by the microtremor observational instrument. There are three advantages on this method: We will be able to make a structural model,
1) reducing cost and time to put the data picked up from a plan into the analytical model, 2) without drawings and specifications, and 3) considering the aging of the structure and the defects in construction. The observed structure is ’58 building at Ichigaya campus of Hosei University. This paper develops a new process on structural identification.
A Shape Optimization with B-Spline Function in Fluid Flow Analysis
Kiyomichi Yamguchi, Norio Takeuchi
Received: March 30, 2012    PDF   Abstract
This research shows the formulation about the optimal shape design of a product in consideration of the influence of a fluid property, and shows the example related to the optimal
shape design of the air deflector of the big track which assumed the two-dimensional state. B-spline control is used to apply the influence of a complex fluid property to the shape representation. Then simplex method is applied to linear optimization techniques to reduce computational load. The optimal shape design was obtained by the minimum design variable by using the control point of B-spline as a design variable.
Development of Active Learning Tools in Distance Education with Sakai CLE
Yuji Tokiwa
Received: March 31, 2012    PDF   Abstract
In distance education, students in a remote classroom tend not to sustain their motivation, mainly because of a lack of intensity due to non-physical presence of a lecturer. To address this issue, Web based tools were developed with Sakai CLE. On the teacher’s PC, this system can display not only the student’s name but also the student’s attributes – id, future career, interest, club, faculty, and entrance time. Then, the teacher by name can call on the appropriate student whose attribute is related to the topics of the lecture. This system will promote active learning style lectures and end up with achieving better learning in universities.
Substituent Effects on the Gas-Phase Acidities of Benzoic Acids
Kazuhide Nakata, Mizue Fujio, Kichisuke Nishimoto, Yuho Tsuno
Received: April 5, 2012    PDF   Abstract
Relative gas-phase acidities of ring-substituted benzoic acids were theoretically determined using proton transfer equilibria. Substituent effects of this system were compared with those on the gas-phase stabilities of anionic systems to confirm that the gas-phase acidities of benzoic acids are governed by three kinds of electronic effects: inductive, resonance, and saturation effects. Following substituent effect analysis with an extended Yukawa-Tsuno equation gave an excellent linear correlation. The present system in gas phase is concluded to be essentially anionic and different from that in solution which is the standard system of Hammett’s  constants.