background: peak expiratory flow rate (pefr) is recommended as a tool for control of asthma. the purpose of this study was to determine the normal value of pefr in the healthy high school children in babol, iran. methods: this study was conducted on 470 healthy high school children (285 girls, 185 boys with the age between 14-18 years). for the determination of pefr we used mini wright peak flo...

nowadays, tunneling in urban areas is a common activity for a variety of transportations such as subways, water supply, lifelines andsewers that may require blast operations. the characteristics of stress waves of the blast are quite different from earthquake waves. the blast waves are usually of high frequency content, short duration, equality of amplitudes in horizontal and vertical direction...

impact pile driving is a multi-component problem which is associated to multi-directional ground vibrations. at first, vibration is transferred from the hammer to the pile and then to the common interface of pile and soil. this is then transferred to the environment and has great impact on the adjacent structures, causing disturbance to residents and also damage to the buildings. it is of high ...