introduction: during the thirty years ago noise pollution increased quickly in the urbane communities that motorcycles are chief sources of noise. the objective of this study is reduction of noise emitted from motorcycle exhaust, applying engineering design. materials and methods: in this pre-experimental study, current condition of noise emitted from motorcycle exhaust and physical parameters ...

in this paper the interior noise level of a vehicle due to structural vibration, named structure borne noise, as a part of nvh analysis has been investigated. first structural analysis is performed and vibrational behavior of structure carried out due to power plant excitations. then interior acoustic cavity response for such excitation and resultant noise is determined. vibrational analysis is...

the effect of different frequencies of noise (150;300 and 600 c/second) on the time of fatigue has been studied on rats. the method of swimming has been used for this study . the results show a significant decrease in the average time of fatigue of the rats subjected to the noise compared with the control group. the possible mechanisms are discussed.

We investigated the issue of noise pollution in the Bidboland gas refineryby noise measurement and surveys. The Bidboland gas refinery has several process units.The sound pressure levels were measured at several places, such as units of 200, 300,400, 500, boiler, powerhouse area, cooling towers pumps, and maintenance area, and thecorresponding noise maps were produced by using sound plan softwa...

the equivalent noise level in large cities has been growing due to the population growth, uncontrolled production of cars, and the existence of worn out cars. on the other hand, heavy traffic has increased the amount of noise problems for residents of medical and educational centers, research institutes and residential area (or sensitive centers to noise) built in highway bounds and it has also...

Background: Many elderly individuals complain of difficulty in understanding speech in noise despite having normal hearing thresholds. According to previous studies, auditory training leads to improvement in speech-in-noise perception, but these studies did not consider the etiology, so their results cannot be generalized. The present study aimed at investigating the effectiveness of envelope-b...

We investigated the issue of noise pollution in the Bidboland gas refineryby noise measurement and surveys. The Bidboland gas refinery has several process units.The sound pressure levels were measured at several places, such as units of 200, 300,400, 500, boiler, powerhouse area, cooling towers pumps, and maintenance area, and thecorresponding noise maps were produced by using sound plan softwa...