Earticle

The object of this paper is to estimation of noise reduction effect of road noise by operating condition due to tire noise regulation. A prepare the countermeasure of the noise reduction according to collect tire/road noise data under various influencing factors by using the tire test method. To accomplish the object : A automotive is used as a test platform to test tire/road noise by changing different types of tires and using the On-Board Sound Intensity test system. The influence of inflation pressure, road, load, speed and pattern type on tire/road noise is compared and analyzed. At the same time, the mechanism of tire/road noise is analyzed, which provides an experimental basis for tire noise reduction.

Blade angle adjustment is one of the few noise-control measures available to operators of light sport aircraft fitted with ground-adjustable propellers, because engine speed cannot be lowered freely without penalising take-off performance. Reducing noise by changing the blade angle, however, also changes static thrust, so the two effects must be weighed together. This study converts A-weighted sound pressure levels and static thrust measured on a Rotax 914 UL powered light sport aircraft into a single evaluation index. A specific noise level, defined as the A-weighted level minus ten times the common logarithm of static thrust, is introduced, together with an exchange rate expressing noise reduction per unit of thrust loss. Four blade angles from 14 to 20 degrees were examined at three engine speeds. At the take-off setting the specific noise level was lowest between 16 and 18 degrees, while the 16 degree setting gave the highest exchange rate at 0.46 dB(A) per one percent of thrust loss. At the cruise setting only the 14 degree case reduced noise, at a markedly lower exchange rate. The results provide a numerical basis for selecting blade angles at training aerodromes where noise complaints are frequent.

In this study was conducted with focus on the change in vibration characteristics in the rail to analyze the noise produced in the rail upon operation of slide mechanism in power seat for vehicles. Preferentially, the motor rpm was simultaneously measured about operating noise, vibration as operating into direction of forward and backward with the slide mechanism. And, modal test was conducted according to operation position of the seat rail, through which overall analysis was conducted for the effects of vibration characteristics of the rail on operating to noise. According to the results, it could be seen that resonance occurred between the 2nd natural frequency generated on the left upper rail and the 3rd order of motor rotation to affect the operating noise.

Purpose: This study was to examine the effects of noise block on anxiety and vital sign of gynecologic laparoscopic surgery. Methods: The data were collected from March to May 2011. Participants were sixty patients with gynecologic laparoscopic surgery, divided into 30 of experimental group and 30 of control group at C University hospital located in I city. The day before surgery, demographic data, trait-state anxiety and vital signs were measured at ward. After noise block, the data were measured using VAS anxiety and vital signs before anesthesia and in recovery room. And then state anxiety and vital signs were measured in ward after surgery. The data were analyzed by x2-test, t-test, repeated measured ANOVA and Bonferroni comparison method using SPSS/WIN 19.0. Results: After conducting noise block program, the experimental group showed significant decrease in state anxiety and heart rate compared to those of the control group. But there were not significant differences in VAS anxiety, systolic pressure and diastolic pressure between two groups. Conclusion: This program can be regarded as an effective nursing intervention for the management of anxiety with gynecologic laparoscopic surgery.