RESUMO
Noise is one of the most harmful factors in the work environment, which is very important to control. There are various techniques to achieve this goal. One of the most important of them is the use of noise absorbers. Absorbent materials are often used to counteract the effects of reflected noise from hard surfaces and reduce their level. This is an experimental-applied study conducted in the physical factor laboratory of the Faculty of Health. The purpose was to predict the Noise absorption rate of combined and independent absorbers under different conditions and frequencies using the new ENC (engineering noise control) software. The sound absorption determination was carried out in 5 stages, including sound frequency analysis for the source, measurement of the dominant frequency, measurement of the absorption coefficient of absorbent materials in different conditions, measurement of the limit frequency (peak frequency of noise absorption) and comparison of the software results with the findings of the impedance tube in Real conditions. The best absorption mode for combined and independent absorbents is using a 5 cm rock wool absorbent with a 2 cm thick air layer behind it without a polyurethane absorbent layer and a 10 cm wide rock wool absorbent with a 1 cm air layer behind it without polyurethane layer. A polyurethane layer on the stone wool absorber decreased the amount of noise absorption for high frequencies. The results obtained from the best absorption conditions in the ENC software were consistent with the findings from the impedance tube device in real situations. The results of this study showed that suitable and optimal conditions of sound absorption could be achieved by using the ENC software, correct design, use of suitable absorbers, changes in the physical parameters of the absorber, and the use of a combined absorber.
RESUMO
BACKGROUND: The health care workers (HCWs) at the frontline of fighting COVID-19 are at higher risk for mental health problems, including stress, anxiety, depression, and insomnia. This study aimed at assess the status of occupational stress in the three occupational groups of nurses, physicians and hospital cleaning crew facing COVID-19 patients in hospitals of Kerman province in Iran. METHODOLOGY: This cross-sectional descriptive analytical study was performed on 290 medical staffs including nurses, physicians and cleaning crew facing COVID-19 patients working in different hospitals in Iran in 2020. Demographic information form and occupational Stress Questionnaire (HSE tool indicator) were used to collect data. The health and safety executive (HSE) questionnaire has 35 questions and 7 areas, which was developed in the 1990s by the UK Health and Safety Institute to measure occupational stress. RESULTS: The mean score of total dimensions among HCWs was 2.93. Communications, Manager support, Changes and Demand factors with scores of 2.76, 2.77, 2.83 and 2.87 had the greatest impact on participants' stress levels, respectively. Also, Colleague support factor with a score of 3.38 had the least effect on stress levels. Also, according to the results, 87% of nurses, 79% of cleaning crew and 67% of physicians had a partial to high levels of stress that, on average, 77.5% of the HCWs participating in this study had at least a small amount of stress. CONCLUSIONS: The mean stress score among the participants of the present study was between high stress level and moderate stress level. Factors such as communications, manager support, change and demand had the greatest impact on employee stress levels. Therefore, by improving the communication between people working in hospitals, increasing managers' support for staff, and reducing workplace demands such as reducing workload and improving workplace environment, the stress level of staff in hospitals during the outbreak of COVID-19 can be reduced.
