Showing 7 results for Mousavi
R. Golmohammadi , H. Ebrahimi, M. Fallahi, A. Soltanzadeh, S. S. Mousavi,
Volume 4, Issue 1 (5-2014)
Abstract
Introduction: Electromagnetic field emitted by laptops are known as extremely low frequency (ELF) Waves. The aim of this study was to investigate the intensity of electric and magnetic field with extremely low frequency emitted by common laptops.
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Material and Method: Intensity of electric and magnetic field were measured on four sides of 40 common by used laptop at the distance of 30, 60 and 90 cm. Measurements ere done according to standard in four functional model including: non-performing turned on, sleep mode, performing office program and performing audio visual files.
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Result: Magnetic field values for all laptops were almost constant and about 28-32 mA/m. The results of measurements related to the electric field showed different values at distances of 30, 60 and 90 cm around the laptops on four sides. Moreover, mean electric field on the keyboard at the four operating modes were statistically different for DELL and hp laptops (P< 0/05).
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Conclusion: The results of this study showed that laptops produce extremely low frequency (ELF) electric and magnetic fields which their intensity depends on laptop type, laptop operation mode and the location of the measurement.
F. Golbabaei, S. H. R. Mousavi, M. R. Pourmand, H. R. Pour Agha Shahneshin, A. Rahimi Foroushani, R. Bakhtiari,
Volume 5, Issue 1 (4-2015)
Abstract
Introduction: Volatile organic compounds such as xylene, which are the main constituents of the oil and petrochemical industries, have serious impacts on health and can cause adverse effects on the environment. It is clear that release of these compounds into the environment should be controlled. The two-phases partitioning stirred tank bio-reactor is one of the newest methods for treating these compounds which have few side-effects besides of having appropriate efficiency since itdestroyscontaminant completely and transform it tosafer compounds.
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Material and Method: In this study, a two phase partitioning stirred tank bio-reactor, in lab scale, was used for treating the gas stream containing xylene vapors. The aqueous phase containing the bacteria Pseudomonas putida and nutrients inserted into the bioreactor with 3:1 ratio and system performance was evaluated for 432 hours in the concentration range of 1000 mg/m3 to 3500 mg/m3
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Result: Empirical findings of this study showed that the maximum, minimum and average of removal of xylene vapors by stirred two phase bioreactor containing a pure strain of Pseudomonas putida were 94.00, 54.00 and 84.94 percent, respectively.Furthermore, maximum, minimum and average of elimination capacity of xylene were obtained 93.00,24.00 and 62.02 g/m3/h, respectively
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Conclusion: Overall, the results of the present research revealed that the application of two phase stirred tank bioreactors (TPPBs) containing pure strains of Pseudomonas putida was successful for treatment of air streams with xylene.
Tahereh Mousavi, Farideh Golbabaei, Mohammad Reza Pourmand, Sasan Rezaei, Mostafa Hosseini, Mehrdad Helmi Kohneshahri, Ensieh Masoorian, Ali Karimi,
Volume 7, Issue 2 (6-2017)
Abstract
Introduction: Nowadays, HEPA filters is used in hospitals, clean rooms, microbiology hoods, ventilation of surgery rooms, and Pharmacy for removing microorganisms and reduce health hazard. The aim of this study is to increase the efficiency of HEPA filters with UVC radiation to reduce the density of airborne microorganisms.
Material and Method: The closed–loop chamber was made to evaluate Staphylococcus epidermidis, Bacillus subtilis bacteria and Aspergillus Niger, Penicillium fungi. The concentration of fungi and bacteria suspension Respectively was 106, 107 CFU/ml. After the suspension was prepared, it was sprayed into the closed loop chamber by nebulizer. Sampling was done with UVC radiation (1.8 mW/cm2 Illuminance) and no radiation (dark) that included time periods 60, 90 and 120 minutes. Microorganisms density was determined in term of CFU/m3.
Result: The result showed that there was a significant difference between UVC radiation and dark section for all the microorganisms (epidermidis, subtilis, Niger and Penicillium) at each time periods (P value< 0.05). This indicates that concentration of four microorganisms were decreased at all the time periods. UVC radiation could change the essential molecular substances for cellular factor. UVC can penetrate the cell walls of microorganisms. thus nucleic acids and other cellular vital material affected and will cause the destruction or inactivation of microorganisms.
Conclusion: UVC radiation is effectiveness to decrease concentration of four microorganisms. because UVC radiation could remove both bacteria and fungi. While the other studies in other countries, UVA radiation is only effective in reducing bacteria. Therefore, achieved greater efficiencies of HEPA filters, using HEPA filters with UVC will have a significant effect on reducing the density of microorganisms.
Rouhaldin Moradirad, Mojtaba Haghighat, Saeid Yazdanirad, Rouhalah Hajizadeh, Zohre Shabgard, Seyed Medi Mousavi,
Volume 8, Issue 4 (12-2018)
Abstract
Introduction: Noise is one of the most harmful industrial agents and there are different methods to control it. Fuzzy analytical hierarchy process is an appropriate technique for selecting the best choice among several control methods. Therefore, the aim of this study was the selection of the most suitable sound control method using fuzzy hierarchical analysis (FAHP) technique in a refinery plant.
Material and Method: The present study was a cross-sectional research in a refinery plant. After identifying the main sources of the noise in the studied palnt, five criteria and ten noise control methods were selected using a questionnaire and Delphi methods. Then, Fuzzy hierarchy analysis was applied for the selection of the best noise control alternative.
Result: The results showed that the performance with a final weight of 0.277 and the non-interference in the process with a final weight of 0.06 were most and least important criteria, respectively. Meanwhile, worker enclosure had highest score (0.207) of the control methods.
Conclusion: In general, the results showed that best criterion for selection of the suitable noise control method is performance. What’s more, based on the results, worker enclosure was selected as best noise control method in the refinery.
Saeid Yazdanirad, Farideh Golbabaei, Amir Hossein Khoshakhlagh, Vali Sarsangi, Mehdi Yaseri, Seyed Mahdi Mousavi,
Volume 12, Issue 1 (3-2022)
Abstract
Introduction: Prevention of heat-related diseases requires the participation of the workers. For this reason, the aim of this study was the development and validation of the tools for evaluating awareness and practice related to heat stress among the workers of warm workplaces.
Material and Methods: The various items and factors related to the awareness and practice of the workers were identified by the literature review. Then, several questions for evaluating these items were designed. In the next step, the reliability and validity of the questionnaires were appraised using calculating the content validity ratio (CVR) and content validity index (CVI), and Cronbach’s alpha coefficient, respectively. After that, these questionnaires were completed by 2338 employees of six industries in various regions of Iran. Finally, collected data were analyzed using SPSS software.
Results: In total, 77 questions, including 53 questions on awareness and 24 questions on practice in six groups of water and beverages, food, snacks and additives, heat exchange, thermal strain risk factors, clothing and heat protection equipment, and heat-related disorders and body reactions, were designed. The values of content validity index (CVI) of remained questions in the questionnaires of awareness and practice were equal to 0.954 and 0.824, respectively. The values of Cronbach’s alpha coefficients of these questionnaires were calculated by 0.755 and 0.716, respectively. The values of the chi-square divided by degrees of freedom (CMIN/DF) and root mean square error of approximation (RMSEA) in the construction of the awareness questionnaire were computed as 4.58 and 0.079, respectively. These values in the construction of the practice questionnaire were calculated by 2.33 and 0.084, respectively.
Conclusion: The results showed that the designed questionnaires had appropriate reliability and validity and could be used to evaluate the awareness and practice in warm workplaces.
Seyed Mahdi Mousavi, Ali Karimi, Seyed Abolfazl Zakeriyan, Mehrdad Mehravar,
Volume 12, Issue 1 (3-2022)
Abstract
Introduction: Permit-to-work system (PTW) system is a documented system to control the activities with inherent risks and probability of accident occurrence. To inform the performance and efficiency of a system, it must be periodically monitored and evaluated, and the permit to work system is no exception of this principle. The aim of the present study was to design and develop software for evaluating the performance of the PTW system.
Material and Methods: This study included two main stages. At the first stage, based on the literature review and interview to the academic and industrial experts, the PTW questionnaire for evaluating the performance was created. The second stage involved the design and implementation of an initial version of a software and the investigation of its usability. Designing the software was performed using system development life cycle (SDLC). The usability of this software was evaluated by Think -Aloud method. Finally, the users’ satisfaction was measured using the Questionnaire for User Interface Satisfaction (QUIS) questionnaire.
Results: Based on the results of the QUIS questionnaire, the overall satisfaction of the designed software was 7.71 in a nine-point scale. The scores of the software performance, display and user interface features, software terminology and information, learning, and overall system capabilities were obtained as 7.58, 7.37, 7.75, 8.11, and 7.74, respectively. Also, the outputs of the excel and SPSS software were in accordance with those of designed software, which show the reliability of the outputs of the designed software.
Conclusion: The designed software facilitate the proper and systematic analysis and it is flexible to evaluate the PTW system and represent types of reports in predefined structures that can be a useful tool in the process industries such as oil and petrochemical refineries and other similar industries.
Leila Omidi, Hossein Karimi, Saeid Mousavi, Gholamreza Moradi,
Volume 12, Issue 3 (9-2022)
Abstract
Introduction: Safety climate potentially affects safety performance in high-hazard industries. Resilience is a developing concept and is defined as the ability that can affect the continuous improvement of safety performance. The present study assesses the influence of organizational resilience on workers’ safety performance in a steel-manufacturing industry. In this regard, the safety climate mediates the effect of organizational resilience on safety performance.
Material and Methods: A cross-sectional study was accomplished in the steel manufacturing industry in 2021. The survey included three parts: (1) organizational resilience, (2) safety performance, and (3) safety climate. Besides, the organizational resilience was measured by a scale with six dimensions and 19 items. Also, safety performance was assessed by six items regarding two performance dimensions (i.e., safety compliance and safety participation). In addition, safety climate was measured by 19 items, comprising four dimensions (i.e., safety communication, supervisor safety perception, coworker safety perception, and work pressure).
Results: The structural equation modeling results showed that the organizational resilience and safety climate had significant impacts on safety climate (β = 0.23, P ≤ 0.05) and safety performance (β = 0.43, P ≤ 0.05), respectively. Also, the indirect results indicated that safety climate mediated the relationship between organizational resilience and workers’ safety performance.
Conclusion: The increment of organizational resilience and safety climate improves workers’ safety performance. Besides, organizational resilience and related dimensions (e.g., reporting culture, learning, and awareness) improve the safety performance dimensions (i.e., safety compliance and safety participation).
