This paper investigates the effect of various modifications to an acoustic steel string guitar on lowfrequency dynamics and sound pressure level. Modifications include string tension, sound-hole area and depth, bridge pin mass, top plate mass, stiffness and damping. Frequency response measurements are provided for all modifications considered. A lumped parameter model is found to capture the ch...

  Abstract   Background: Previous studies have indicated an unspecific correlation between noise   exposure and blood pressure disturbances. Blood pressure disturbances could be caused   by the environmental hazards such as noise exposure. The aim of this study is to analyze   whether there is a relationship between noise exposure and hypertension.   Methods: Atotal sample of 218 workers workin...

original article   introduction: wind-turbine noise emission and its environmental impact are considerable issues nowadays. considering the importance of the issue, the purpose of this study was to prepare noise map and wind turbines sound characteristics on the largest wind farm of iran. method: this study was carried out in two phases:1) in order to prepare the daytime sound level (ld) noise ...

background : cement industry has many process units. basically all of these units can be considered as a source of noise. since noise pollution is defined based on its offensive hearing effects, the importance of the noise sources depends directly on the number of workers in the unit.   materials and methods : an experimental study has been done at tehran cement factory to recognize and analyze...

background: noise is defined as unwanted or meaningless sound that apart from auditory adverse health effects may distract attention from cues that are important for task performance. human performance is influenced by many job-related factors and workplace conditions including noise level. objective: to study the effect of noise on human performance. methods: the participants included 40 healt...