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Journal of Technology and Social Science (JTSS, J. Tech. Soc. Sci.)

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ISSN 2432-5686

 


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Vol.5, No.1

 

TABLE OF CONTENTS

 

Articles

 

Characteristics of Whispering Gallery Mode of Light within Microring Resonator System

Nithiroth Pornsuwancharoen and Phichai Youplao

Journal of Technology and Social Science, Vol.5, No.1, pp.1-7, 2021.

Abstract: A whispering gallery mode (WGM) of light generated by the light within a nonlinear microring resonator system is studied. Such a system is a microring structure and made of an InGaAsP/InP material. The simulation result shows that the proposed ring resonator system can be potentially fabricated within the micro-scale range and used for a micro light source, which can be employed as the passive laser source. The tunability of the source and beam size can be managed by the two side rings, which is the nonlinear microring resonator. Moreover, the output free spectral range are also increaded and suitable for the high capacity information requirement.

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Acoustic Finite-Element Analysis with Air-Viscosity Damping for Narrow Square-Section Tubes

Manabu Sasajima, Takao Yamaguchi, Yue Hu and Mitsuharu Watanabe

Journal of Technology and Social Science, Vol.5, No.1, pp.8-15, 2021.

Abstract: We study the propagation of sound waves through air in narrow square-section tubes, where the speed and phase of sound waves are affected by viscous air damping. We developed a new finite element method (FEM) considering the effects of air viscosity. This method was developed as an extension of the existing FEM for porous sound-absorbing materials. The results of a numerical calculation for a narrow three-dimensional square-section tube model were validated using the proposed FEM. The validation was performed through comparison with results obtained from existing calculation methods. The relative error between the proposed and theoretical methods was also validated.

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Development of Sound Absorption Coefficient Prediction Tool of Laminated Ultrafine Fibers

Yoshio Kurosawa, Tetsuya Ozaki and Tsuyoshi Yamashita

Journal of Technology and Social Science, Vol.5, No.1, pp.16-23, 2021.

Abstract: This report describes research regarding a sound-absorption coefficient prediction technique for laminated ultrafine fiber. As the sound-absorption material used for interior noise reduction in automobiles, we considered fiber with a diameter of several m. When the fiber diameter decreases, the sound-absorption coefficient typically increases., but it is necessary to laminate it whether it is fiber materials with the fiber diameter and several levels to some extent that rigidity becomes small when fiber narrows and is destroyed. We calculated an acoustic feature from fiber diameter, fiber density, thickness, materials density in extra-fine fiber materials this time. In addition, in combination with Transfer Matrix method, we developed other fiber materials and the plural technique that we could predict when we laminated it. We compare the experimental and calculation results, and verify the usefulness of this technique. The prediction of the sound absorption coefficient of the product before the sample making in this way enabled it.

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Calculation for Normal Sound Absorption Coefficient of Porous Media Using FE Model for Impedance Tube

Yoshio Kurosawa

Journal of Technology and Social Science, Vol.5, No.1, pp.24-34, 2021.

Abstract: The impedance tube is used for measuring the normal sound absorption coefficient of a sound absorbing material such as an automobile. Such as urethane foam and felt with high density, the sound absorption coefficient measurement result may be different depending on the contact situation between the cut sample and the impedance tube wall. In order to elucidate this phenomenon, the impedance tube was modeled with finite elements and modeled the contact condition by placing a spring between the cut sample and the impedance tube wall. By changing the spring coefficient, it was tried to reproduce the way of vibration of the cut sample occurring at the time of actual sound absorption, to elucidate the influence of improvement of prediction accuracy and the contact condition of cut sample and impedance tube wall on sound absorption coefficient. It was introduced calculation result by transfer matrix method and calculation result using finite element model by Biot-Allard theory, comparison of experiment result. In addition, the results of comparing the results of FEM and TMM by changing the Young's modulus and flow resistance of the sample are introduced.

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Sound Absorption Analysis Using FEM for Meta-Material

Yoshio Kurosawa, Kazuki Fukui and Ouch Som On

Journal of Technology and Social Science, Vol.5, No.1, pp.35-40, 2021.

Abstract: The performance enhancement of the acoustic insulation is demanded for the high frequency for interior noise of car. The importance of car comfort is emphasized, and there is also a response to the United Nations external noise regulations, and quietness is required from the design concept stage. Measures on the sound source side are also limited, and measures on the vehicle body side are important in consideration of cost and weight. In this study, we considered using the material of the new structure for the undercover of the car to improve the quietness outside the car. A simple model of metamaterial (repeated structure) is created using the finite element method, and the result of analyzing the sound absorption characteristics by numerical calculation is reported.

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Development of Teaching Materials for Cryptography at Senior High School

Kenji Yamaguchi, Anna Kuwana and Katsuhisa Kagami

Journal of Technology and Social Science, Vol.5, No.1, pp.41-46, 2021.

Abstract: We are engaged in the development of teaching methods and materials for information and mathematics in secondary education. In this education program, we develop teaching materials for cryptography. Cryptography is a very interesting subject area that uses information as well as math knowledge and skills. In this paper, we will provide an overview of cryptography, the actual situation in the field of education, and the application under development.

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