vol.23 (2010)

Bulletin of Research Center for Computing and Multimedia Studies
Vol.23, 2010 ISSN 1882-7594

Magnetization and 1/f Fluctuation Frequency Characteristics of Ferromagnetic Materials by Visualizing the Dynamic Magnetic Wall Movements
Takashi Ishii, Yoshifuru Saito
Received: February 20, 2010    PDF    Abstract
Bitter method is most commonly observing way of the magnetic domains even though it is limited to the surface of specimen. To observe the magnetic domains by Bitter method, a drop of magnetic liquid is put on a target magnetic material surface after electrical field polishing processes. Applying magnetic field to this magnetic material covered by magnetic fluid makes it possible to observe the magnetic domain dynamics by a microscope. We have previously reported that local magnetization characteristics could be obtained from the visualized magnetic domain dynamics. Final purpose of our research on visualized magnetic domain dynamics is to work out a fully automatic quality control system. And also, we plan to deduce some rules governing the magnetic domain dynamics system from the visualized thin magnetic materials domain dynamics. Present paper, we try to visualize the magnetic domain wall dynamics of ferromagnetic materials when applying not only the anhysteretic magnetizing condition but also mechanical stress. We try to extract 1/f as well as 1/f fluctuating frequency characteristics from the magnetic domain wall dynamics, where a is the generalization of 1.
Wavelets Analysis of the Magnet Field Distributions around Contact-less Power Supplier
Shogo TAKADA, Yoshifuru SAITO
Received: February 21, 2010    PDF    Abstract
All of the modern electrical devices are composed of two major parts: one is the electrical signal processing part, and the other is the power supplier. Recent electrical devices are spreading in use not only the conventional consumer electronics products but also electrical vehicles. A reason why electrical vehicles should be developed is simply the antipollution of earth atmosphere, i.e., the electrical motors are employed instead of combustion type engines. The electrical vehicles requires a battery system which should be charged up by an external power source. This means that a contactless power supplier is extensively convenient to practical use for battery charging of the electrical vehicles. Contactless power supplier is composed of a transformer having the distinct primal and secondary coils separated by air gap. Because of the electromagnetic compatibility problem, it is essential to keep the leakage magnetic fields around the contactless power supplier as low as possible. This paper carries out the wavelets multi-resolution analysis to the magnetic field distributions around the transformer having the distinct primal and secondary coil separated by air gap. As a result, it is found that the most reasonable core head shape of the transformers has the most dominant 1st order wavelet spectrum, i.e., the biggest 1st order wavelet spectrum and negligible higher order wavelets spectra. This means that there is no leakage magnetic field around the contact-less power supplier.
Dynamic Response Analysis by using Hybrid-type Penalty Method
Haruhito Shishido, Asako Shibata, Norio Takeuchi
Received: February 25, 2010    PDF    Abstract
A penalty function is used to satisfy a weak continuity of the displacement in HPM. In the iterative method such as the step by step integration for dynamic problems, the influence of the penalty function to numerical solution is not studied enough. In this paper, formulation of HPM for the dynamic problem with the implicit method using Newmark’s β method is shown and the accuracy of the solution is verified by numerical example. In the two-dimensional problems, the solution which is the same as FEM is obtained, and a similar result is obtained in a beam theory. According to the implicit method, a solution of same accuracy as FEM is obtained in the dynamic analysis in HPM using a penalty function.
Phase Transition of NaCl Aqueous Solution by Molecular Dynamics Simulation
Mika Koyama, Yosuke Kataoka
Received: February 26, 2010    PDF    Abstract
The boiling point of the sodium chloride aqueous solution is examined by molecular dynamics simulation. The boiling point is observed by the internal energy and volume under NTP ensemble simulation at 1 atm. The numbers of molecules in the basic cell are as follows: 200 SPCE water and 20 NaCl. The effect of this salt is found to be too large on the boiling point.
Physical Properties of Solid Oxygen
Hiroyuki Taneoka, Yosuke Kataoka
Received: February 26, 2010    PDF    Abstract
The phase transitions in solid oxygen are studied by molecular dynamics simulation. The low temperature ordered phase (α-phase) and others are obtained from a small size unit cell (N = 4). One is Pa3 structure and the other is the γ ordered phase. The Gibbs free energies of these three phases are compared by thermodynamic integration. The α-phase is most stable at low temperatures.
Phase Transition Simulation of Nitrogen
Maya Saiki, Yosuke Kataoka
Received: February 26, 2010    PDF    Abstract
The phase transition of nitrogen was researched by using a molecular dynamics method. The experiments on a lot of conditions were performed, and a steady molecular grouping was able to be obtained. Therefore, the structures of the melt, vaporization and 3-type molecular crystals were seen.
Phase Transition from Ice VIII to Ice VII studied by Molecular Dynamic Simulation
Junpei Sawada, Yosuke Kataoka
Received: February 26, 2010    PDF    Abstract
Phase Transition from ice VIII to ice VII is studied by molecular dynamics simulation under high pressure. The orientation ordered ice VIII changed to disordered ice VII at T = 540K in the NTV N = 128 system. The entropy change is discussed in this phase transition.
Vaporization in Helium-Argon Mixture by Molecular Dynamics Simulations
Hiraku Koyama, Yosuke Kataoka
Received: February 26, 2010    PDF    Abstract
Vaporization of helium and argon mixture is studied by molecular dynamics simulations. The numbers of molecules in the basic cell are 128 for both species. The ensemble is NTP. The two liquid phases are observed at low temperatures. At intermediate temperatures, the vapor phase with main component of helium and liquid phase of argon are found. Finally, the evaporation is completed, where there is the gaseous mixture of helium and argon. These features are studied by the average potential energy and volume as functions of temperature.
The Dissolving Process of Sodium Chloride in Water by Molecular Dynamics Simulation
Keiichiro Tokunaga, Yosuke Kataoka
Received: February 26, 2010    PDF    Abstract
The solving process of NaCl into liquid water is simulated by molecular dynamics. The numbers of molecules in the unit cell are SPCE water 250 and NaCl 4. The mean square displacement and the rotational correlation function are analyzed to obtain the relaxation time. The pair correlation function and the running coordination number are also calculated in the intermediate state in the solving process.
Rapid Cooling of Ne Gas by Molecular Dynamics Simulation
Takahiro Kitano, Yosuke Kataoka
Received: February 26, 2010    PDF    Abstract
The cluster structures of Ne gas are obtained by molecular dynamics simulation. The initial configuration is that of Ne gas and the temperature is changed to very low abruptly. The energy of cluster depends on the density slightly. The phase transition temperature from cluster to gas phase changes as a linear function of the logarithm of molar volume.
A Method of Defect Visualization in the Metallic Materials by Resonance Type ECT Sensor
Takafumi Hosohara, Yoshifuru Saito
Received: February 26, 2010    PDF    Abstract
ECT (eddy current testing) is extensively used to inspect such as elevator, escalator, and airplane, nuclear electric and power plant without any destruction. This paper proposes a method of resonance type ECT sensor system which makes it possible to detect the defect of metallic plate. Operating principle of this system is based on the essential nature of parallel resonant electrical circuit. When the primary coil is working as a sensing part and the secondary coil, i.e. a target metallic material, is magnetically coupled with the primary coil, the primary resonance frequency and impedance of the ECT sensor system greatly depend on the secondary impedance change caused by a defect such as cracks. By means of a simple eddy current property, we have tried to visualize the capacitance arisen in cracks of which the traditional ECT sensor system neglects this capacitance effect. Even though more precise experimentally proof is necessarily, we have succeeded in visualizing a crack effect in the target thin metallic materials.
Numerical Method for Unsteady Heat Transfer Problems by using Hybrid-type Penalty Method
Hiroki Saito, Yasuki Tajiri, Norio Takeuchi
Received: March 2, 2010    PDF    Abstract
HPM can apply to not only the analysis of the solid mechanics but also the problem of the scalar field. For example, in the case of heat transfer analysis, a weak continuity of the temperature can be satisfied between subregion by using a penalty function. If this method is used, in the case of steady state problem, a solution of the accuracy that is equivalent to analytical solution is computed. However, like the case of the dynamic problem in the solid mechanics, the influence of the penalty function to the solution is not enough discussed in time integration in the unsteady problem. In this paper, it applied the Crank Nicholson method which is the implicit method to time integration, and verified accuracy of solution. As a result, even if it used the penalty function, the accuracy comparable as analytical solution was obtained.
On Escape Guiding Method in Elderly-people Institution by using Simulation
Mari Kohara. Norio Takeuchi
Received: March 3, 2010    PDF    Abstract
The fire drill including vulnerable groups in disaster in the elderly-people institution is difficult virtually. It is necessary to perform an evacuation simulation beforehand, to consider refuge action, and to be well-known enough to a guide. In this paper, the nursing home of the unit type in the special elderly nursing home in which the high person requiring care lives also in an elderly-people institution is made applicable to examination, and an escape guiding method was examined by simulation. Of course, evacuation time becomes short, so that care workers increase in number. However, when there are few care workers, it is effective if a care worker collects and acts.
Identification Problem of Building by Microtremor Observation
Kazunari Akimoto, Nagayuki yoshida
Received: March 5, 2010    PDF    Abstract
The vibrational characteristic of a building of three stories is investigated by both of observation and numerical analysis. Obsevation is perfomed by microtremometers with high sensitivity set on the floor in the building at midnight. The obtained data is analyzed through F.T.T. to evaluate the natural period and vibrational mode. On the other hand, structural model for F.E.M. analysis is made from design plan in detail on mass and rigidity of beams, columns and bearing walls. Finally numerial results of eigenvalue analysis for models are compared with those of F.T.T.
Dynamic Analysis of Particle Models
-A study on Particle Configurations-

Tomohiro Sukegawa, Naoto Matsunae, Nagayuki Yoshida
Received: March 4, 2010    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. Soil particles, however, have various configurations. Therefore it is inadequate to only use the circular element. This paper proposes a new model which consists of pairs of circular elements with viscous combination which have a similar effect with the elliptical element.
A Study on Wave Transmitting Boundary by CIP Method
Keisuke Tajima, Nagayuki Yoshida
Received: March 4, 2010    PDF    Abstract
When analyzing the wave propagation problem in the infinite or semi-infinite elastic body, 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 C1P method to the finite element method. Its validity is presented by analyzing one-dimensional rod subjected the impulse load at one end.
Frequency Analysis of Time Domain One Dimensional Signals and Its One Application
Satoshi Nojima, Yoshifuru Saito
Received: March 4, 2010    PDF    Abstract
Ferromagnetic materials, i.e., iron steel and its composites, are widely used as the frame parts of various artificial products and constructions such as a building, bridge and so on. Because of its mechanical property, iron steel is most popular in use for the frame materials to maintain their mechanical strength. On the other side, nondestructive testing of iron steel is an extremely important way in order to keep their mechanical reliability. One of the deterministic differences between the ferromagnetic and nonmagnetic materials is that all of the ferromagnetic materials when applying external magnetic field attracts major magnetic fields; and also magnetization process of ferromagnetic materials always accompanies with the Barkhausen effect. The Barkhausen effect is a phenomenon caused by movement of the magnetic domains accompanying with the discontinuous magnetizations. In order to carry out the nondestructive testing of iron steels with high reliability, this paper proposes one of the signal cognition methodologies based on the fluctuation frequency characteristics of the Barkhausen signals.
Melting in Amorphous Carbon by Molecular Dynamics Simulation
Tomohide Hayashi, Yosuke Kataoka
Received: March 5, 2010    PDF    Abstract
The melting in the amorphous carbon is observed by molecular dynamics simulation. Tersoff potential which is famous as the intermolecular potential function for a classic, molecular simulation between the carbon atoms is used in the present simulation. The melting point in the amorphous carbon is assigned by the mean square displacement plot.
Molecular Dynamics Simulations of Water and Methanol Cluster
Kotaro Iidaka, Yosuke Kataoka
Received: March 5, 2010    PDF    Abstract
Clusters of methanol and water are generated by rapid cooling of gas state by NTV molecular dynamics simulation. The thermodynamic properties and the pair correlation functions are examined at many temperatures. The methanol-water bond breaks at T=120 K in the case of 30 water molecules and one methanol.
Melting of Al2O3 by Molecular Dynamics Simulation
Yuki Kobayashi, Yosuke Kataoka
Received: March 5, 2010    PDF    Abstract
Melting of Al2O3 is studied by molecular dynamics simulation. The tried potential functions are Oxide and CMAS94. CMAS94 function is better to examine the melting of Al2O3 The obtained melting point depends slightly on pressure.
Extraction of 1/f fluctuation frequency components from music and its application to human physiology
Keiko SUGAI, Yoshifuru SAITO and Kiyoshi HORII
Received: March 5, 2010    PDF    Abstract
Most of the engineering products have to equip the well designed human interface. In order to enhance the human interface ultimately, it is essential to take the human physiological effects into account. This means that most of the engineering product design has to consider the human sensing feelings as well as physiological effects into account. This paper concerns with the extraction of 1/f fluctuation frequency components from music and its application to the human psychophysiology. Fourier analysis is applied to the music in order to extract the 1/f fluctuation frequency characteristics. According to the Fourier analysis, music is classified into two major categories: rich 1/f fluctuation or not. Electroencephalograph analysis to the objects hearing the music composed of the 1/f fluctuation components reveals the human physiological effects.
Household Burglary Analysis in Tokyo using ArcGIS and Socio Economic Data
Nozomi Iwakura
Received: March 5, 2010    PDF    Abstract
Criminologists and crime prevention practitioners are increasingly aware of the importance of places of crimes. According to environmental criminology, criminal events result from factors such as likely offenders, suitable targets, and the absence of capable guardians against crime converging nonrandomly in time and space. There has been few prior Japanese psychological research that studied the relationship between crime rate and urban area. The present study predicts criminogenic environment quantitatively using ArcGIS and socio economic data.
Numerical Simulation of Failure Behavior of Si3N4 by Hypervelocity Impact of a Small Particle
Yasuhiro Ogawa, Kazuyoshi Ara, Eiichi Sato, Sunao Hasegawa
Received: March 5, 2010    PDF    Abstract
The silicon nitride (Si3N4) will be used for the thruster for the Venus probe and is expected to encounter meteoroid impacts in outer space. Meteoroids and debris environment play an important role in the reduction of the lifespan of a spacecraft. However, as meteoroid impacts on the thruster cannot be recreated in the present experiment facilities on the earth, it is necessary to evaluate the hypervelocity impact phenomenon by numerical simulation. In this study, the failure behavior of Si3N4 in case of hypervelocity impact of a small particle was evaluated by numerical simulation to obtain the basic data for verifying the validity of the simulation method. In addition, impact morphology of Si3N4 at different projectile diameters was also investigated.
An Attempt of Career Education using Visitor Employed Photography - a Research on the Final-year students in Welfare Vocational School
Minora Tazawa
Received: March 5, 2010    PDF    Abstract
The goal of this study was twofold; examination of (1) whether self-understanding in career choice is fostered through the coursework using visitor employed photography (VEP); and (2) whether this coursework was effective for students on choosing their career. In the first study, whether the coursework using VEP foster self- self-understanding in career choice was examined through longitudinal research. The results showed the changes in categories between pictures taken at time 1 and those at time 2. Half of the students recognized that the categories of the pictures they took had changed. In the second study, the effectiveness of the coursework on career choice was examined with using both subjective and objective indicators. The results showed that 80 % of the students who took the coursework had chosen their career by two months before their graduation. More than 40 % of the students recognized that the coursework using VEP was actually helpful in their career choice. It was suggested that coursework using VEP has certain effect as career educational strategy.
Forecast of sound radiation from Golf Club
Mitsuo Iwahara, Kosuke Kubota, Yukihiro Saitou, Akio Nagamatu
Received: March 8, 2010    PDF    Abstract
The sound simulation program forecasts the sound radiation. It has been developed in our laboratory. A past research forecast the ball impact sound of the golf club. As for past research results, the difference was seen in “Sound collected by the excitation experiment” and “Sound that had been calculated by the sound simulation program” in the driver of the golf club. Therefore, the accuracy of the program is confirmed and improved in the present study. Then, it is preferable to be able to understand the accuracy of the program precisely. The experiment and the calculation are conducted by using the plate and the cylinder with few error margins of the finite element model, and then, this research compares, and examines the surface vibration velocity and the sound pressure. As a result, if the error margin of the finite element model is few, it has been understood that the straight advancement sound from the surface vibration velocity and the surface vibration velocity is correctly computable. And, the influence of the diffracted sound was able to be confirmed.
VIBRATION CHARACTERISTICS OF SMALL DIRECT CURRENT FAN
Tatsuya Yoshida, Akio Nagamatsu, Mitsuo Iwahara
Received: March 10, 2010    PDF    Abstract
The object of this research is three kinds of small direct current fan. The causes of the vibration under operation in a small direct current fan are an unbalance and a pressure fluctuation. The vibration is a big problem in the use environment of a small direct current fan, and the vibration reduction of a small direct current fan and the evasion of the resonance are requires. In this paper, the vibration phenomenon of a small direct current fan was analyzed while operating, and the spectrogram of the object was obtained. The phenomenon was understood by the Experimental Modal Analysis and Finite Element Method.
Transfer Path Analysis with Inverse Matrix Method
Mitsuo Iwahara, Yuki Kawaguchi, Akio Nagamatsu
Received: March 10, 2010    PDF    Abstract
Recently, mechanical noise and vibration problems, including automobile and product development, came to be regarded as a differentiating factor between competing products and they are becoming more important issue. Especially in the automotive development process for this issue, pathway analysis (Transfer Path Analysis below, TPA) has been analyzed. This is a technique to identify the contribution from more than one source of vibration. In order to make the product of low noise and low vibration and shorten the process, this is required high accuracy and efficiency. In this study, analysis focused on the contribution of each vibration excitation force identification and pathway analysis using the inverse method, validation and accuracy of the theory is examined. The regular-inverse matrix method, and the pseudo-inverse matrix method are compared. The former is for the case of same number of excitation and response points, and the later is for the case of increasing the number of response points.
NOISE REDUCTION OF STEPPING MOTOR
Mituo Iwahara, Takuto Yao, Akio Nagamatsu
Received: March 10, 2010    PDF    Abstract
The stepping motor which rotates every step can simply realize position control, and it has the characteristics of small size and high torque. For high performance equipment, small size and low cost meet the requirements, and so it was used in a very wide range of applications. However, when driving, the noise is generated. In this research, it was aimed to decrease the noise by investigating, and improve the cause of the noise by the sound and vibration analysis. And production of finite element model is tried for structural modification of entire stepping motor.
Substituent Effects on the Gas Phase Stabilities of Phenylamino Anions
Kazuhide Nakata, Mizue Fujio, Kichisuke Nishimoto, Yuho Tsuno
Received: March 12, 2010    PDF    Abstract
Relative gas phase stabilities of ring substituted phenylamino anions were theoretically determined using proton transfer equilibria. Substituent effects of these anions were compared with one another to discuss what kinds of electronic effects are important to determine the gas phase stabilities. According to statistical analyses, the stabilities of phenylamino anions are 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 + rΔσR + sΔσS) , is necessary in order to correlate the substituent effects of phenylamino anions as well as benzylic anions.
Diesel engine mount with air suspension development
Keita Saito, Haruhiko Okubo, Mituo Iwahara, Akio Nagamatu
Received: March 15, 2010    PDF    Abstract
The diesel engine is used from the viewpoint of the economy for many of present commercial vehicles. However, the diesel engine is larger than the gasoline engines the vibrations, and becomes a problem the influence on the human body by the subsonic vibration and the noise of the high-frequency vibration. The amenity of the environment in the car in a commercial car is an indispensable element for the market rivalry. As for the air spring, the thing that the constant of spring suppresses to about 1/10 compared with a past rubber vibration isolator becomes possible. Then, the feasibility of the strong reduction of the engine vibration with the diesel engine mount that adopts the air spring is examined in the present study. Only the decrease of the subsonic vibration when it was an idol was paid to attention in the present study to improve the idle vibration. It was verified that there was a similar decrement effect in a real car at current year because the thing that was able to be attenuated, that the air mount was bigger than the rubber mount in the bench test with the experiment unit had been proven last year. The present study is Hokkaido Institute of Technology, Muroran Institute of Technology, and a joint research with Wakamu Hokkaido by the support of the north Tec foundation.
Critical Design of Hydraulic Systems for Environmental Compatibility
- Numerical Analysis of Flow in Bubble Eliminator -

Koichi Nagaishi, Yutaka Tanaka, Ryushi Suzuki
Received: March 15, 2010    PDF    Abstract
Liquid containing air bubbles dissolves into liquid caused by a dynamic factor and a thermal factor. Thus, it is important to actively eliminate the air bubbles to avoid bulk modulus change and the damage to the hydraulic machinery toward the development of more environmental friendly and endurable hydraulic systems. This study is designed to remove bubbles in liquid at high flow rate to an extremely small one. At present, we have conducted numerical analysis of liquid flow, offering the optimal equipment design.
VIBRATION ANALYSIS OF BADMINTON RACKETS
Nobuyuki Ishii, Kyohei Terada, Mitsuo Iwahara, Akio Nagamatsu.
Received: March 17, 2010    PDF    Abstract
The badminton can’t be called the famous sports, but they are ones which hold large population of players. In comparison with the tennis rackets, the paper which researched the badminton rackets are few, and they are not so much studied. The research is carried out for the purpose to clarify the vibration phenomenon of badminton racket, it does experimental modal analysis on the badminton racket, and examining the vibration characteristics. We studied the differences of vibration characteristics of the 3 rackets.