Showing 5 results for Monazam
M. Monazam, P. Nasiri, N. Javid Rouzi,
Volume 6, Issue 1 (spring 2009)
Abstract
Background and aims
The paper presents the results of an investigation on the acoustic performance of tilted profile parallel barriers with quadratic residue diffuser tops and faces.
Methods
A2D boundary element method (BEM) is used to predict the barrier insertion loss. The results of rigid and with absorptive coverage are also calculated for comparisons. Using QRD on the top surface and faces of all tilted profile parallel barrier models introduced here is found to improve the efficiency of barriers compared with rigid equivalent parallel barrier at the examined receiver positions.
Results
Applying a QRD with frequency design of 400 Hz on 5 degrees tilted parallel barrier improves the overall performance of its equivalent rigid barrier by 1.8 dB(A). Increase the treated surfaces with reactive elements shifts the effective performance toward lower frequencies. It is found that by tilting the barriers from 0 to 10 degrees in parallel set up, the degradation effects in parallel barriers is reduced but the absorption effect of fibrous materials and also diffusivity of the
quadratic residue diffuser is reduced significantly. In this case all the designed barriers have better performance with 10 degrees tilting in parallel set up.
Conclusion
The most economic traffic noise parallel barrier, which produces significantly high performance, is achieved by covering the top surface of the barrier closed to the receiver by just a QRD with frequency design of 400 Hz and tilting angle of 10 degrees. The average Aweighted insertion loss in this barrier is predicted to be 16.3 dB (A).
Mehdi Ghasemkhani, Mohammad Reza Monazam, Marzieh Abbasinia, Somayeh Mahmoodkhani, Habib Aghaee, Mehdi Asghari, Somayeh Farhang,
Volume 10, Issue 2 (7-2013)
Abstract
Background and aims : Fatigue is indicated as a factor in occupational accidents and diseases and it can reduce individual efficiency. In shift workers who experience sleep disturbance, the occupational accidents and diseases occurring can be aggravated by fatigue. The present study aims to investigate the fatigue intensity and its relationship to insomnia severity among employees of Tehran rolling and steel production company.
Methods : This descriptive analytical study had been done among 180 workers of the mentioned company. Data collection was done by face-to-face survey method and using the standard questionnaires.
Results : Results showed that the fatigue score among fixed-dayshift and rotating-shift workers was 6 and 7 respectively and fatigue level for both groups was 4. In all symptoms associated with fatigue average score of rotating-shift were higher than dayshift and there was a significant difference between them. Relationship between the symptoms of fatigue with Insomnia Severity Index was significant. Warehousing received the highest scores of fatigue and severity of insomnia between different tasks under study.
Conclusion : Our findings indicate that level of fatigue and severity of insomnia among workers of industry is very high. Since this can lead to the occupational accident and reduction efficiency, it is necessary to provide facilities for personnel such as reducing working hours, doing regular rest and exercise during working time, paying sufficient attention to humanitarian needs and improving work system.
Mohammadreza Monazam Esmaeelpour, Esmaeil Shoja, Seysd Abolfazl Zakeriyan, Abbas Rahimi Foroushani, Masoumeh Gharaee,
Volume 15, Issue 2 (6-2018)
Abstract
Background and aims: Whole-body vibration is one of the major factors that cause human discomfort and physiological reactions in industrial environments or vehicles. This study aimed in a laboratory environment to investigate the effect of whole body vibration on human discomfort, heart rate and reaction time in men 20 to 30 years old.
Methods: 40 Male students in Tehran University of Medical Sciences with 26.2± 1.7 years mean of age are participated in this study. All of participants were studied in 4 stages for 20 minutes in four vibration accelerations in x, y and z axis and frequency of 3 to7 Hz including without vibration, 0.56 m/s2, 0.9 m/s2 and 1.25 m/s2 that was produced with vibration simulator. At each stage, a computerized visual reaction time test was taken and reaction times were measured for test and their Heart rate was also recorded using pulse oximetry. At the end of each stage the subjects were given 15 minutes to rest and their discomfort was rated during this time.
Results: The results of this study showed that with increasing whole body vibration acceleration, discomfort rate (P<0.001) increase significantly. Also with increasing whole body vibration acceleration, heart rate (P<0.001) and reaction time (P<0.001) increase significantly.
Conclusion: The results showed that whole body vibration is a factor that affects human physiological and subjective functions. Hence, attending to level of vibration transmitted to human in vibrant environments have an important role in decreasing human discomfort and reducing reaction time in quick and sensitive activities.
Davood Eskandari, Hasti Borgheipour, Mousa Jabbari, Atefe Abdpur, Ghazaleh Monazami Tehrani,
Volume 17, Issue 1 (5-2020)
Abstract
Background and Aim: Employee exposure assessment through long-term monitoring is not feasible due to the complexity of sampling and analysis methods in all operating conditions. The use of chemical exposure risk assessment methods is an appropriate way to evaluate the exposure status of chemical workers in some situations. Of course, there is a need for special considerations to provide a comprehensive technique and to address the shortcomings of current methods such as disregard for existing control measures.
Materials and Methods: In this study, three factors influencing the risk of exposure to chemicals were considered based on the Control Banding (CB) approach, including the Health Hazard Index (HHI) indicating the inherent toxic properties of chemicals, Chemical Occupational Exposure Index (OEI) aims to show the characteristics associated with process conditions and material properties and exposure modes, as well as the Control of Effectiveness Index (CEI), taking into account the engineering and management measures that affect chemical exposure. Then, according to the above method, the risk of exposure to chemicals was investigated in Marun petrochemical Complex.
Results: Chemical exposure risk index (CRI) was calculated from the factors affecting exposure.
Based on the findings of the study, exposure to benzene and 1,3 butadiene with a risk score of 20/01 and 14/35, respectively, obtained highest risk score in the HD unit and in the whole complex Due to the inherent hazards associated with these substances and other factors including exposure duration and poor effectiveness. Also, in all units, due to the low exposure time to chemicals, the lowest risk numbers were reported for similar exposure groups as the Boardman and the head of the unit.
Conclusion: The present method can be used as a non-sophisticated and valid tool for risk assessment of occupational exposure to chemicals. Also, considering the role of control measures and their impact on risk score, this method will be able to provide a more accurate calculation of the working conditions of the personnel when exposed to chemicals.
Mr Davood Eskandari, Ms Ghazaleh Monazami Tehrani, Ms Bahar Aminfar, Ms Hasti Borgheipour,
Volume 20, Issue 2 (1-2024)
Abstract
Introduction: Today, many organizations and companies have some methods and instructions to analyze the causes of accidents, but when an accident occurs, only a simple approach is implemented to analyze the causes of accidents. This study aims to investigate and identify the root causes of accidents in the country's drilling industry and provide a technique for an accurate and more comprehensive analysis of accidents with high intensity and frequency in this industry.
Materials and Methods: The present study was conducted in 4 main stages. In the first step, the lessons learned from accidents in the drilling industry were studied through the method of document review. The factors identified in the first step were weighted by the AHP-Fuzzy method and their impact on the occurrence of the accident was determined according to the expert’s opinion. One of the fatal accidents in an oil drilling company was selected and then the root causes of the accident were analyzed according to the developed model.
Results: Based on the results of the review of documents, 29 factors including organizational, occupational, and environmental factors were identified as the root causes of accidents. Among the second level criteria, the organizational factor with the weighting load of 0.533 had the highest and the environmental criteria with the weighting load of 0.0198 gained the lowest weighting load. Based on the results, it was found that job incompetence is one of the main causes of accidents, and job incompatibility and safety training are among the second and third sub-criteria and are among the main causes of the accident.
Conclusion: In the present study, three factors of organization, environment, and individual based on the theory of human factors as the root causes of industrial accidents in the drilling industry were investigated. Analysis of the study data showed that the designed tool is a simple and quantitative method to find the root causes of accidents in the drilling industry and can be used as a practical and comprehensive method for analyzing organizational accidents.
