This study was designed to measure the noise caused by a 63.20KV transformer in the residential area close to it that consisted of 36 points inside the post and the surrounding area around it (including 29 points+30 points). the results demonstrated that noise caused by the function of the transformer t1 was 59.1dBA with the standard deviation of 6.89dBA and for transformer t2 was 59.89dBA with a standard deviation of 6.86dBA .The measured noise in the west residential area around the post was 54.95dBA with a standard deviation of 1.76dBA, in the east was 54.1dBA with a standard deviation of 2.52dBA and in the south was 49.71dBA with a standard deviation of 1.07dBA.The statistical measurements showed no significant difference in the measured noise around in the mentioned direction.The results of this measurements manifested that the noise measured in all residential areas close to the post was more than noise permitted in night.

One of the most common and important sources of noise in the residential environments are vehicles such as airplanes and subways. Trafficking of vehicles in streets and highways, psychologically, have damaging impacts on people living close to such areas. The development and expansion of the trading and industrial units is another factor that causes more and more exposure to noise.We have aimed at measuring the noises caused by vibration of subways of the Line of Karaj-Tehran-Mehrshahr and its effect on its surrounding area.To study this effect we designed a mathematical model and put the information of this subway line in the mentioned model. Then we analyzed the findings.This model demonstrated that we can control the harsh noise of the subway by reducing the speed of the train to 60Km/h in some points and increase in other parts to 130Km/h.

Background and Aim: About 1.5 percent of exceptional children suffer from impaired hearing and this factor affects the teaching and learning process. The aim of this study was to investigate the effect of frequency of knowledge of results (KR) on the learning of children with hearing impairment.

Methods: Twenty-four individuals with hearing impairment with the mean age of 10.56 with SD 2.53 years (range: 7-14 years) were divided into three homogenous groups according to their records after pre-test. They practiced for eight sessions according to mentioned ways (feedback of 0%, 50% and 100%). The acquisition, learning and translation tests were run. MANOVA with repeated measures and ANOVA were used to analyze the data from the acquisition, retention and transition tests.

Results: All groups progressed during training and at various stages (acquisition, retention and transition). However, the results of the comparison between means of the three training groups showed significant differences in the acquisition process (p=0.008), learning (p=0.001) and transition (p=0.035). This means that feedback training groups (100%) had better performance in acquisition process, and also in retention and transition (50%).

Conclusion: According to the results of this study, too much feedback interferes with learning of tasks in individuals with hearing impairment and feedback (50%) had better learning. This finding shows that rules regarding feedback also affect the people with hearing impairment.