مجله مهندسی بهداشت حرفه ای
سال هفتم شماره 3 (پاییز 1399)

Perforated panels are one of the most common resonant absorbers for sound control. In this study the acoustic properties of non-flat perforated panels in oblique angle and field diffusion were investigated in both numerical and laboratory methods at 1.3 octave frequencies.

3 non-flat shapes were considered for perforated panel and their absorption performance was compared with the usual shape of (flat) perforated panel. After determining the best shape in terms of absorption coefficient, it was constructed according to the standard  ISO 354at the approved dimensions and the desired structural properties and was subjected to absorption coefficient test in the reverberation chamber

Numerical simulation results showed that the shapes defined in this paper all improve the absorption coefficient at the mid and high frequencies and also the shape C has higher absorption coefficient at the lower frequencies than the flat and two defined shapes. The results of measurement of absorption coefficient showed that the highest absorption coefficient of 0.77 is observed at the frequency of 160 Hz. Also, to compare the results, these conditions were implemented in numerical environment and the absorption coefficient was calculated according to the existing relationships.

Surface shape is effective in improving the absorption performance of these adsorbents and comparison of the numerical and laboratory results showed that acceptable agreement for these two methods is found in most of the frequency spectrum and the numerical method is able to predict this quantity with good accuracy.

Acrylonitrile is a potential carcinogen for humans and exposure to vapors of this substance can have a variety of adverse effects on employees in the petrochemical industry. Therefore, the present study was conducted to determine the level of exposure and assess the quantitative health risk of exposure to acrylonitrile vapors in the exposed personnel of a petrochemical complex.

In this cross-sectional study, which was conducted in a petrochemical complex, a total of 45 inhaled air (3 samples per person) was sampled. Samples were collected using absorbent tubes containing activated charcoal from SKC. The samples were prepared and analyzed according to the 1601 NIOSH method using the VARIAN CP-3800 chromatography gas device. Finally, the US Environmental Protection Agency (EPA) method was used to determine the level of exposure of employees and the health or non-cancer risk index (HQ).  

The results of the present study showed that the average density of acrylonitrile vapors in the studied petrochemical complex is on average  71.1±122.8 micrograms per cubic meter (0.033±0.056ppm). The non-carcinogenic risk was also calculated to be 4.04±6.93.

Regarding the fact that the quantitative health index of acrylonitrile vapors exposure in the studied petrochemical complex is higher than the limits recommended by the relevant organizations, engineering and necessary management control measures to define an acceptable level of risk, such as revision of ventilation systems, the limitation of exposure hours and the use of personal protective equipment are essential to improve the situation.

musculoskeletal disorders is one of the most common occupational injuries in the workers of manufacturing industries, one of which is one of the 10 injuries that lead to absenteeism. therefore, the present study examines the musculoskeletal disorders due to work and the effect of interventions on pain improvement and its relationship with job satisfaction of workers factory workers.

In this quasi-experimental study, the statistical sample was 32 individuals including two control(n=16) and experimental(n=16) groups. The Nordic questionnaire was to identify work-related musculoskeletal disorders exposure, Quick Exposure checklist(QEC) method to evaluate risk factors for musculoskeletal disorders, Visual Analogue Scale(VAS) index to determine the severity of musculoskeletal pain, and Minnesota questionnaire to assess work satisfaction level. Also, the frequency level was used to evaluate musculoskeletal-disorders prevalence, and the statistical dependent and independent t-tests were completed to determine the effect of ergonomic interventions on pain and work satisfaction.

The lumbar(63.39 percent), the knee(58.28 percent), the wrist(33.33 percent) and the neck (30.71 percent) areas were the highest prevalence for musculoskeletal disorders. Also, the results of statistical paired t-test showed that after 8 weeks of ergonomic interventions, the pain in the lumbar(P=0.008) and knee(P=0.002) areas significantly decrease and the work satisfaction significantly increases(P=0.001). In addition, a negative significant relation between work satisfaction and musculoskeletal disorders was observed(P=0.001).

The prevalence of musculoskeletal disorders has a negative relation with work satisfaction. Also, ergonomic interventions have positive effects on decreasing the pain of work-related musculoskeletal disorders and increasing the work satisfaction among workers

human resource is the main factor of the sustainable development in the leading organizations,HSE management system helps organizations by integrated and synergycal HR arrangement, and other resources of the organization for a healthy atmosphere, without accidents and damages. So that affects the final performance of the organizations. The goal of this study is to design HSE competency management pattern for the organizational posts those affect on HSE system performance in power plant company.

The method used in the research is a combined research method. First, quantitative methods were used based on the qualitative method and in order to prioritize them, quantitative methods were used. Content analysis method was used to analyze the events.

after studying theoretical and empirical bases and all of the organizationchr('39')s documents in this regard and by using questionnaire and interviewing, the determinants of HSE-COP were defined and organizational posts, based on the each criteria were determined.  Prioritization of organizational posts based on their impact on system performance by TOPSIS method defined. Finally considering the nature of these organizational posts, their position in the organizational chart, the study of the relevant models and standards and the opinions of the experts, the component and shaping of the pattern was explained.
Conclusion  : 30 organizational posts were identified as organizational posts affecting the performance of the HSE system in the organization and 5 components of knowledge, skills, ability, perception and attitude, responsibilities and authorities were determined as the components of the Competency management model.

Pyrethroid including deltamethrin are one of the most common insecticides that are used extensively in agriculture and control of insects. Oxidative stress is one of the main mechanisms of pesticides toxicity. Many plants contain high levels of antioxidants that can counteract and remove the free radicals. The current study was performed to assess the adverse effect and oxidative stress of deltamethrin on kidney organs in male rats and to evaluate the protective role of Salvia officinalis extract in alleviating the detrimental effect of  This toxicant.

Thirty Wistar rats were randomly divided into five groups of six. Group I control, group II received deltamethrin (15mg/kg), group III received both deltamethrin (15mg/kg) and Salvia officinalis extract (100mg/kg), group IV received both deltamethrin (15mg/kg) and Salvia officinalis extract (200mg/kg) and group V received Salvia officinalis extract. The treatment was extending for one month for all groups and after that the kidney tissues were collected for further analysis.

The results showed that Salvia extract reduces the toxic effects of deltamethrin. Salvia extract significantly reduced malondialdehyde levels and improved glutathione peroxidase activity. The results of kidney tissue pathology also confirm Salviachr('39')s protective effect.

The protective effect of Salvia extract can be due to phenolic compounds and antioxidant activity, which can be used as an effective factor in the prevention and improvement of the toxic effects of deltamethrin.

Nowadays one of the most important occupational health issues is musculoskeletal disorders, which are prevalent in almost occupations. The purpose of the study is to evaluate musculoskeletal disorders and related factors in the housewives of Yazd province.

This cross-sectional study was carried out on 396 samples selected housewives in Yazd province in the year 1398. The information was collected by completing the Nordic questionnaire through the selected samples. The prevalence of musculoskeletal disorders and ergonomic assessment of posture was assessed by using the questionnaire and the REBA method, respectively. Data analysis was done by using the independence and ANOVA tests in SPSS version 22.

The most prevalent musculoskeletal disorders in the housewives were in the lumbar, knee, and neck that 67%, 53%, and 43% of the samples had the disorders, respectively. The prevalence of musculoskeletal disorders in some areas of the body increased because of an increase in the number of children, declining in welfare, and the use of assistive devices at home. Also, the prevalence of musculoskeletal disorders has had a significant impact on the calf and ankle.

The results showed that the prevalence of musculoskeletal disorders in the study population is high. Age, marriage age, height, weight, number of pregnancies and children, education, status of welfare and residential, daily exercises, used equipment, elevator, and staircase were the things that produce musculoskeletal disorders. According to the big population of housewives, it is recommended more extensive studies on disorders in this group.

Noise absorber is considered as main method for noise control based on noise propagation in indoor workrooms. This study aims to evaluate the effectiveness of environmental noise control using noise absorber at press workshop based on ISO 11690 method.

This experimental study was performed at press workshop of the metal structure company in 2019. The environmental noise control is installation of metal mesh using perforated gypsum tile with a layer of stone wool at the press workshop ceiling. Intervention evaluation was performed based on ISO 11690 method which is included determination of the rate of noise spatial decay from omnidirectional source based on distance doubling. The noise level was measured at the defined distance from an artificial noise source along the length of the workshop.

The environmental noise was reduced approximately from 3 to 4 dB after installing an acoustic ceiling. These noise reductions were considerable at the frequency spectrum of 2000 Hz, 4000 Hz and 8000 Hz.  Based on distance doubling, noise spatial decay of 4 dB from omnidirectional source was observed so that it represent a reduction in the surface noise reflections of the press workshop and consequently, environmental noise reduction.

The efficiency of environmental noise control was determined with high accuracy using noise spatial decay curve from omnidirectional source and compare it’s with the recommended optimal conditions and with the free field noise propagation curve.

The most logical decision when making a device is to apply the principles of ergonomics in the design stage. One of the main goals of computer application in ergonomics is to develop a tool that allows the product to be evaluated at the beginning of the design process.

The study was conducted at a paint spraying unit at a home appliance factory. Then, the digital model of the posture was simulated in CATIA software with the most deviation from the normal state. After evaluation by Rola method, biomechanical analysis was performed on the human model. Finally, according to the results of RULLA, ergonomic interventions were performed in the software and the new workstation was re-evaluated. The study also looked at a personchr('39')s biomechanical status, such as the loads on the spine, the force and torque applied to the mannequin joints during color spraying.

The final score of the color spray posture evaluation showed that it is at the level of corrective measures 4 and immediate changes are needed. In this posture, the position of the forearm, muscles, wrists and arms, legs, upper body and neck was inappropriate. Proposed interventions included seat design and weight adjustment of the spray gun.

The results showed that by focusing on the organs under pressure and presenting an ergonomic design with the aim of reducing the pressure with CATIA software, musculoskeletal problems can be significantly solved.