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BACKGROUND: Lighting is one of the environmental factors affecting the performance of the control room operators. Therefore, the aim of this study was to compare the control room operators' visual performance in two different illumination conditions at a combined cycle power plant through field-work. METHODS: Sixteen operators in day shift were evaluated with the Freiburg Visual Acuity test (FrACT) software at two lighting systems with different intensities. It includes the first phase with fluorescent illumination system (Power: 40 W, Color Temperature: 4000 Kelvin, Luminous Flux: 2780 Lumen and Model: Pars Shahab) and the second phase with a combined illumination system includes fluorescent and LED (Power: 48 W, Color Temperature: 4000 Kelvin, Luminous Flux: 5400 Lumen and Model: Mazinoor). RESULTS: Based on the results, visual performance index and visual acuity significantly increased after the intervention (p < 0.001). As to contrast, more lighting significantly reduced the percentage of recognized contrast (p < 0.001) and increased the contrast performance index (p < 0.001). CONCLUSIONS: The results of this study showed that increasing the intensity of light from the values below the allowable limit to the values above the allowable limit would increase the visual indicators in individuals.
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AIM AND BACKGROUND: Studies show that the risk of musculoskeletal disorders (MSDs) among computer users is more than the other occupations. The present study aimed to determine the effect of educational intervention based on the "stages-of-change" model on practicing the correct posture to reduce MSDs among computer user staff of Tehran University of Medical Sciences (TUMS). METHODS: This is a quasi-experimental study which was carried out on 176 staff of TUMS. The study population was divided into two case and control groups, each including 88 participants. A self-structured as well as a standard questionnaire was used to collect the data. Data then were analyzed using descriptive and analytical tests. RESULTS: There was no significant difference between both groups in terms of mean score of stages of change, perceived benefits and barriers, self-efficacy, and processes of change before the intervention. However, the mean score of these variables increased for case group 3 months after the intervention. In addition, case group participants reported lower MSDs in their neck, lower back, elbow, and knee compared to control group. CONCLUSION: Ergonomic educational intervention based on the "stages-of-change" model has a positive impact on reduction of MSDs. Therefore, these disorders can be decreased through reducing working hours, changing the work conditions in accordance with ergonomic principles, dedicating some time for staff exercise, and holding educational courses for the personnel.
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BACKGROUND: The wind turbine's sound seems to have a proportional effect on health of people living near to wind farms. This study aimed to investigate the effect of noise emitted from wind turbines on general health, sleep and annoyance among workers of manjil wind farm, Iran. MATERIALS AND METHODS: A total number of 53 workers took part in this study. Based on the type of job, they were categorized into three groups of maintenance, security and office staff. The persons' exposure at each job-related group was measured by eight-hour equivalent sound level (LAeq, 8 h). A Noise annoyance scale, Epworth sleepiness scale and 28-item general health questionnaire was used for gathering data from workers. The data were analyzed through Multivariate Analysis of variance (MANOVA) test, Pillai's Trace test, Paired comparisons analysis and Multivariate regression test were used in the R software. RESULTS AND DISCUSSION: The results showed that, response variables (annoyance, sleep disturbance and health) were significantly different between job groups. The results also indicated that sleep disturbance as well as noise exposure had a significant effect on general health. Noise annoyance and distance from wind turbines could significantly explain about 44.5 and 34.2 % of the variance in sleep disturbance and worker's general health, respectively. General health was significantly different in different age groups while age had no significant impact on sleep disturbance. The results were reverse for distance because it had no significant impact on health, but sleep disturbance was significantly affected. CONCLUSIONS: We came to this conclusion that wind turbines noise can directly impact on annoyance, sleep and health. This type of energy generation can have potential health risks for wind farm workers. However, further research is needed to confirm the results of this study.
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BACKGROUND: The aim of this study was to determine heat stress effect on physical capacity of semi-professional footballers in Iran by means of oxygen consumption measurement, heart rate monitoring and WBGT assessment environmental conditions. METHODS: This study compared two different thermal environmental conditions related to sub-maximal exercise and its effect on human physical capacity. Thirty two male footballers (age 25.9 ± 1.4 year; height 176 ± 2.9 cm and weight 71 ± 9.8 kg) were investigated under four workloads (50,100,150 & 200 W) in two different thermal conditions in the morning (WBGT=21 °C) and afternoon (WBGT=33 °C) in summer. Each test cycle lasted for 10 minutes with a 10 min interval for recovery and rest between every workload. In the end of each stage, the heart rate, blood pressure, skin temperature and oral temperature were measured and recorded. Expired air was collected and its volume was measured using standard Douglas bags. The WBGT index was also used to monitor the stressful heat condition. RESULTS: Heart rate and VO2 consumption findings for different workload showed a significant difference between morning and afternoon (P<0.001). HR and VO2 consumption in both morning and afternoon courses showed a liner relation (r=0.88, r=0.9 respectively). CONCLUSION: With increasing work load beside heat stress, heart rate and oxygen consumption increased. It is recommended that with Ta>35 °C or WBGT>28 °C, physical activates and performing exercises should be avoided in order to reduce the risk of heat stress-related conditions in athletes.