vol.24 (2011)

Bulletin of Research Center for Computing and Multimedia Studies
Vol.24, 2011 ISSN 1882-7594

Thermodynamics on Real Gas by van der Waals Equation of State
Yosuke Kataoka, Yuri Yamada
Received: October 7, 2010    PDF    Abstract
Equation of state on internal energy is derived by thermodynamics on the basis of van der Waals equation of state on pressure. Isothermal reversible expansion, adiabatic reversible expansion and adiabatic free expansion are studied by these equations of state. Joule-Thomson effects are discussed on the equation of state on internal energy.
Evacuation Simulation from Movie Theater including Wheelchair User
Shiho Kasai, Norio Takeuchi
Received: February 26, 2011    PDF    Abstract
When a wheelchair user sees a movie while sitting down on a wheelchair, they cannot choose a seat. Under the present conditions, they appreciate a movie at a decided place. One of the reasons of this is the escape delay of a wheelchair user when a disaster occurs. And another reason is the hindrance of evacuation of other spectators by them. However, it is unknown whether this is true. In this paper, when the wheelchair user is included in the evacuation activity from the movies theater, influence to their activity is examined by the simulation. And we investigate the evacuation route, seat arrangement and entrance arrangement which do not have a wheelchair user escape delay.
Development of Linear Element for in-Plane Deformation of Hybrid-type Penalty Method
Takashi Horita, Norio Takeuchi
Received: February 26, 2011    PDF    Abstract
In the discrete limit analysis of the complex structure and the material using HPM, the analysis becomes possible at a realistic level when modeling with the linear element as well as FEM. However, HPM is a just developed model, and since the Solid element has been preceded and developed, the line element is not prepared. Then, we develop the linear element of HPM for the analysis of the framed structure and the analysis combined with the solid or plane element. This paper shows brief formulation of a truss element, a beam element, and the linear element that combined them based on the cubic displacement field in a three-dimensional problem. In addition, the accuracy of the solution of proposed element is confirmed according to simple example.
Adiabatic Reversible Expansion of Isobutane
Yuki Sukawa, Yosuke Kataoka
Received: March 1, 2011    PDF    Abstract
The decrease of temperature in the adiabatic reversible expansion of isobutane was examined by van der Waals equation of state. By choosing the suitable expansion process, reasonable cooling effect is estimated by reverse Carnot cycle. The molecular dynamics simulation was tried to realize the adiabatic reversible expansion of isobutane.
Properties of Carbon Dioxide
Takumi Saito, Yosuke Kataoka
Received: March 1, 2011    PDF    Abstract
Phase transitions in carbon dioxide are studied by molecular dynamics simulations. The low temperature crystal structure was obtained by NTV ensemble simulation at T = 10 K in 4-molecule system with FCC lattice. The 108-molecule system was used to obtain the melting and the boiling points by NTP molecular dynamics simulations. The change of phase was confirmed by the radial distribution function and the mean square displacement. The critical point was also estimated by NTV ensemble simulations. Phase diagram was drawn in T-p phase space, which was not so good under low pressures.
Identification Problem of Structure by Optimization Method
Kazunari Akimoto, Nagayuki Yoshida
Received: March 4, 2011    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 two advantages on this method: We will be able to make a structural model, 1) without drawings and specifications, and 2) considering the aging of the structure and the defects in construction. The proposed method makes it possible to evaluate the stiffness of multi-mass structural system by using the observational data and the genetic algorithm as optimization method.
Dynamic Analysis of Particle Models
-A study on Particle Configurations-

Naoto Matsunae, Soichiro Kanzaki, Nagayuki Yoshida
Received: March 2, 2011    PDF    Abstract
In this research, we simulate the dynamic behavior of soil by the discreet element method. The circular element is usually used because the computing time is economical for its simple procedure on the contact problem. On this paper, there are four main suggestions. First of all, we re-consider the analysis of elliptical model and establish its method. Using this method, we build a new program. Based on the numerical results, we propose a new model which consists of pair of circular elements with same size combination which have a similar effect with the elliptical element, in order to improve the computational efficiency. Through this method, we investigate the dynamic behavior and the void ratio of three different types of model. Finally, the relation between void ratios and the number of elements is made clear.
Inversion Point in Joule Thomson Effect of Argon
Koutaro Shitomi, Yosuke Kataoka
Received: March 3, 2011    PDF    Abstract
The inversion point of argon was examined by molecular dynamic simulation. Enthalpy was calculated as a function of density at the constant temperature. Its minimum corresponds to the zero point of Joule-Thomson coefficient, which is the inversion point. It was compared with the theoretical value on van der Waals equation of state.
Van der Waals Coefficients Determined by Molecular Dynamics
Hiroyuki Ozeki, Yosuke Kataok
Received: March 3, 2011    PDF    Abstract
Van der Waals coefficients a and b were determined by molecular dynamics simulations. Molar internal energy is a linear function of the inverse of molar volume with the coefficient a. The coefficient b was obtained by the van der Waals equation on pressure. The examined molecular systems were helium, neon, nitrogen and argon. The liquid-gas coexistence points were calculated by Gibbs energy in the case of argon.
Phase Transition of NaCl Solution by Molecular Dynamics Simulation
Ryo Otsuka , Yosuke Kataoka
Received: March 3, 2011    PDF    VIDEO    Abstract
The phase transition of the sodium chloride aqueous solution was examined by molecular dynamics simulation. An application program “Materials Explorer 5.0” was used to obtain average potential energy, pressure and pressure tensor. The temperature dependence of the anisotropy of the pressure tensor was observed and the surface tension was discussed to calculate the boiling point.
Phase Transition Simulation of Hydrogen Fluoride
Tatsuhiro Ozaki, Yosuke Kataoka
Received: March 3, 2011    PDF    Abstract
Molecular dynamics simulations were performed to investigate phase transitions in the hydrogen fluoride. The melting temperature, boiling temperature and critical point are studied. The results are compared with the macroscopic experimental results and nitrogen system. The orientation correlation function is calculated to see the hydrogen bonded nature.
Phase Transition of Alloy Al-Cu by Molecular Dynamics Simulation
Aro fujimoto, Yosuke Kataoka
Received: March 4, 2011    PDF    Abstract
Phase transition of Al-Cu alloy (Al3Cu) was studied by molecular dynamics simulation. Potential parameters were estimated by Lorentz-Berthelot rule. The heating and cooling process gave reasonable average transition temperature. The change of structure was examined by the pair correlation function. The phase transition was confirmed by the mean square displacement.
Molecular Dynamics Simulations of Free Expansion of Argon and Water
Hitomi Kakinuma, Yosuke Kataoka
Received: March 4, 2011    PDF    Abstract
The free expansion of gaseous argon and water were examined by molecular dynamics simulations. The potential functions adopted in this study were Lennard-Jones for Argon and SPCE water for water. The unit cell model for water was SPCE. The number of molecules in the unit cell was set at 108, 256, 500, 864, 1372, 2048, 2916 and 4000 to investigate whether the number of molecules affected thermodynamic properties in the free expansion. The difference values of temperature depended weakly on the number of molecules in the unit cell. We further compared the difference values of temperature obtained from simulation with the ones calculated using the Van der Waals theory.
Phase Transition Simulations on Xenon
Tomonori Nakada, Yosuke Kataoka
Received: March 4, 2011    PDF    Abstract
Phase transitions are studied by molecular dynamics simulations on xenon. The melting temperature, boiling temperature and critical point are examined between liquid and vapor phase The obtained values are not so good corresponded with the macroscopic experimental ones. The 12-6 Lennard-Jones potential function seems to give too high boiling points, which is used commonly in rare gas system.
Comparison of Stabilities on Solid NaCl, KCl and CsCl
Koichi Hirakawa, Yosuke Kataoka
Received: March 4, 2011    PDF    Abstract
Comparison of stabilities was performed in solid NaCl, KCl and CsCl by molecular dynamics simulations. Each crystal of compound was assumed to have two types of crystal structure i.e. NaCl-type and CsCl-type at the lowest temperatures. NaCl-type structure was more stable than Cs-type structure when the interatomic potential was assumed as the molecular dynamics package “Materials Explorer”. Revised potential function was proposed to explain the phase transition in solid CsCl.
Identification Problem of Structure by Microtremor Observation
Yuuki Fujioka, Nagayuki Yoshida
Received: March 4, 2011    PDF    Abstract
We have carried out the microtremor observation for Hosei University 58′ building and three dimensional modeling. This study has two processes by the observational method and the analytical method. In observational method, we put microtremor meters on each point of every floor of the building and recorded the vibration data. Next, this data is inputted to FFT procedure to examine the natural periods and vibrational characteristics. In the analytical method, we investigated the drawings of the building and made the analytical model in detail. The 3D FEM program developed by authors is used to resolve the eigen value problem of this model. From the numerical results, 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.
Verification of Effect of Heat Island Easing that Green and Water of Koto Ward, Tokyo bring
Yohei Shingo, Toshiya Suzuki, Kiyoe Miyashita
Received: March 4, 2011    PDF    Abstract
This research verified the effect of the heat island easing by the sea breeze, the large-scale park, the water park, and Tokyo bayside for Koto Ward, Tokyo where large-scale urban development such as Odaiba, Toyosu, and the sunamachi was remarkable. Urban environmental climate map was able to catch the possibility of an urban cooling effect with the sea breeze and the park and the vertical interval of the rejection calorie by the difference of the land use and differences of the earth surface temperature of the seaside part and the inland areas by the satellite image. Moreover, it was able to be proven that natural environment such as green spaces, and water spaces had the potential of the cooling effect by using CFD and water and green environment invented the effect of the heat island easing.
Wave Transmitting Boundary by CIP Method in One and Two Dimensional Elastic Solids
Keisuke Tajima, Nagayuki Yoshida
Received: March 7, 2011    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 should be attached to the boundary of the finite analytical region. Generally the discrete models are installed at the boundary. But, in this research, we propose a new method which combines the CIP method to the finite element method. Its validity is presented by analyzing one dimensional rod model subjected the impulse load, and two dimensional ground model loaded in also analyzed.
Shape Optimization of Bubble Eliminator
- Relation between Diameter of Vent Port and Outlet Port -

Sayako Sakama, Yutaka Tanaka, Ryushi Suzuki
Received: March 9, 2011    PDF    Abstract
Air bubbles in working oil influence stiffness and efficiency of hydraulic systems, thus it is important for technical issues to eliminate the air bubbles actively from the hydraulic oil. Bubble eliminator is a device that removes air bubbles by using a swirling flow. The purpose of this study is to design optimal shape of the bubble eliminator. Flow and pressure distributions in the bubble eliminator have been studied by numerical analysis. In this paper, it is numerically evaluated to confirm effects of some parameters: diameter of outlet port and diameter of vent port. The optimal dimensions of the bubble eliminator are proposed and the performance of bubble eliminator is evaluated by numerical simulation.
Substituent Effects on the Gas Phase Stabilities of Phenoxide Ions
Kazuhide Nakata, Mizue Fujio, Kichisuke Nishimoto, Yuho Tsuno
Received: April 3, 2011    PDF    Abstract
Relative gas phase stabilities of ring substituted phenoxide ions were theoretically determined using proton transfer equilibria. Substituent effects of this anionic system were compared with those of benzylic anions to discuss what kinds of electronic effects are decisive to the gas phase stabilities. According to statistical analyses, the stabilities of phenoxide ions were found to be governed by three kinds of electronic effects: inductive, resonance, and saturation effects. It has become apparent that an extended Yukawa-Tsuno equation, ΔEX = ρ(σ0 + r ΔσR + sΔσS), is necessary in order to correlate the substituent effects of phenoxide ions as well as other anionic systems.
Yukihiro Saitou, Kousuke Kubota, Yasutosi Kubota, Mituo Iwahara, Gaku Minorikawa
Received: April 22, 2011    PDF    Abstract
The purpose of this research is development of CAE tool to design the agreeable sound golf club. Therefore, the radiation sound forecast program was made in 2003. Program was created using modal analysis theory and superposition theory of velocity potential. In a past research, the batting sound of the golf club was forecasted. As for past research results, the difference was seen between “Sound measured by experiment” and “Sound calculated by the radiation sound forecast program” of the golf club. Therefore, In this paper, the accuracy of radiation sound forecast program is examined by comparing experiment with calculation by using cylinder model.