2001 Fiscal Year Final Research Report Summary

Pneumatic noise evaluation considering sensitivity

Research Project

Project/Area Number	12650187
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Single-year Grants
Section	一般
Research Field	Fluid engineering
Research Institution	Numazu College of Technology
Principal Investigator	MURAMATSU Hisamii Numazu College of Technology, Mechanical Engineering, Associate Profess, 機械工学科, 助教授 (70219939)
Project Period (FY)	2000 – 2001
Keywords	Pneumatics / Silencer / Electroencephalogram / Beta wave / Stevens power function / Autononomic functionsp / R-R interval variation / Respiration
Research Abstract	Although pneumatic system are suitable for assistance to man, pneumatic noise generated from the system jars on us. The pneumatic noise such as jet noise from discharged air and the noise reduced by silencer is generally evaluated by A-weighted sound pressure level. We, however, feel that the noise decreased the level is loud. In this work, the noise evaluation method utilized electroencephalogram i.e. EEG is proposed. EEG was measured by ten-twenty electrode system. Alpha wave was observed on the occipital when experimental subjects sat down and relaxed in the noise measuring room. During the stimulation of the pneumatic noise, alpha wave was disappeared and beta wave was appeared on the frontal and the central. Loudness is projected on beta wave. For steady noise, relationship between average of electric potential of beta wave and sound pressure was obtained by steavns power function. The expression can be estimate the loudness of pneumatic noise. Furthermore, the pneumatic noise was studied from physiological view. Heart rate, hidrosis, and respiratory of man were measured. Heart rate, coefficients of R-R interval variation, and respiration were increased when experimental subjects were heard the pneumatic noise. Mental sweating was also observed. Explanations based on function of the brain are given. It is cleared that autonomic functions are influenced by the pneumatic noise.