Showing 10 results for Mirzaei
A. Khavanin, K. Azrah, R. Mirzaei, S. B. Mortazavi, H. Asilian, A. Soleimanian,
Volume 4, Issue 2 (7-2014)
Abstract
Introduction: Whole body vibration occurs when human is on a vibrating surface and the vibration influences parts of the body which are far from the contacted part. Up to now, various health-related problems due to whole body vibration have been reported, including back pain, sciatica, gastrointestinal problems, genital problems and hearing impairment. In the present research, vibration was measured about 2000 minutes in 23 train of 4 active lines of Tehran metro in order to determine the rate of subway drivers’ exposed to whole body vibration.
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Material and Method: Vibration meter and SVAN 958 analyzer, made by Svantek company, were utilized for measuring the whole body vibration. The level of weighted r.m.s acceleration for each axis, the combination of axes, peak factor, VDV and other common exiting ratios in the standard were measured and calculated according to ISO 2631-1.
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Result: Findings showed that according to Basic method drivers exposure to vibration is less than the lowest value of health guide critical region (<0.45m/s2). However, based on Vibration Dose Valuation (VDV), the exposure of 12 cases were higher than the lowest value (<8.5 m/s1.75) and only 11 cases were lower than the mentioned amount.
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Conclusion: Investigation of the result obtained from Basic method and VDV method manifested different amounts of vibration exposure in a way that VDV predicts higher level of risk, compared to basic method. The results shows that some presented indicators can not presented the safe zone in human vibration evaluations.
A. Khanin, R. Mirzaei, M. H. Beheshti, Z. Safari, K. Azrah,
Volume 4, Issue 3 (9-2014)
Abstract
Introduction: The most common standards being used for predicting the health risks of whole body vibrations are ISO 2631- and BS 6844, presenting frequency weighting anfd different coefficients for different sensivities in variuse axes. In yhis study, vibration was measured about 900 minutes on 9 trains in one of the active lines of tehran metro with the aim of comparing the mentioned standards in evaluating whole body vibation.
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Material and Method: In this research, in addition to evaluation of different kinds of vibration indicators, the differences of ISO 26331-1 and BS 6841 Standards have also been investigated. The amounts of r.m.s., vibration dose and daily vibration dose were measured in x, y and z axes for drivers seat and x axis for drivers back rest separately according to the instruction of the two standards.
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Result: The mean calculated values of r.m.s and vibration dose on a basis of 135 6841 standard were lower than those values calculated according to ISO 2631 standard. Moreover, the results showed that 3 cases, based on the ISO standard, had risk level of higher than 17 m/s1.75 and 3 cases, had risk level of higher than 15 m/s1.75 value, provided by BS 6841.
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Conclusion: Calculation according to the ISO 2631-1 standard show higher values. Indeed, ISO 2631-1 can provide a more secure criterion company to BS 6841, although the 15 m/s1.75 in BS is lower than the highest level of health guidance caution zone in ISO. Additionally, the association between r.m.s and vibration dose values in ISO 2631 is relatively lower than this association in BS 6841.
K. Azrah, R. Mirzaei, A.r. Sharifi, A. Solaimanian,
Volume 6, Issue 1 (4-2016)
Abstract
Introduction: Whole-body vibration is one of the factors which may have adverse effects on the comfort of passengers and crew of rail transportation vehicles. In this study, the probable impacts of whole-body vibration were explored on the convenience of the passengers of Tehran metro.
Material and methods: Planning, measurement, and pre-analysis calculations were mainly done based on ISO guidelines No. 2631-1, 4. Moreover, measurements and calculations were done using SVAN 958 sound & vibration analysis and Microsoft Excel software, respectively.
Results: Average calculated RMS acceleration values on the levels of seat cushion, seat back, and legs were 0.57, 0.44, and 0.64 m/s2 on the dominant axes, and total r.m.s acceleration in all these three levels equaled to 1.02 with the standard deviation of 0.11 m/s2. Mean Vibration Dose Value (VDV) of total exposure in the minimum and maximum exposure durations were 6.44 and 9.63 m/s 1.75, respectively.
Conclusion: Calculated amounts of dominant axes were mainly ranked as “relatively unpleasant” in the convenience limits of ISO 2631-1, but the total calculated amount of exposure based on WRMS was at “unpleasant level”. The measured VDV amounts were mostly on the z axis, as the dominant one.
Safoura Karimie, Iraj Mohammadfam, Mostafa Mirzaei Aliabadi,
Volume 9, Issue 2 (6-2019)
Abstract
Introduction: Nowadays, human error is one of the main causes of incidents in the industry. One of the vital characteristics of modern industries is that the precise control of key parts of the process is performed by operators from central control rooms, so an error by the control room staff can be disastrous. The present study is aimed at identifying and evaluating human errors in the control room of the petrochemical industry.
Material and Methods: This is a descriptive-analytic case study that was conducted in a control room of the petrochemical industry. In this research, firstly by using hierarchical task analysis (HTA), the tasks in the control room were identified and analyzed. Then, using the extended CREAM method, possible human errors were identified, their cognitive category was determined, and their probabilities were calculated using a new approach based on BN.
Results: The results of the study showed that the most prevalent control modes for the Boardman and the senior board man were strategic and scrambled modes with error probabilities of 0.136 and 0.171, respectively.
Conclusion: According to the results obtained in the modeling section, BN can be proposed as an approach with high processing accuracy and also high accuracy in modeling human errors and problems with high input parameters affecting the output parameter.
Tahereh Eskandari, Iraj Mohammadfam, Mostafa Mirzaei Aliabadi,
Volume 9, Issue 4 (12-2019)
Abstract
Introduction: The safety of CNG stations is important because of their location in urban areas, as well as to prevent accidents and to protect the safety of personnel, property, and environment. An event occurrence analysis with probability updating is the key to dynamic safety analysis.
Methods and materials: In this study, the Failure Modes and Effects Analysis (FMEA) technique was used to determine the hazards of the study unit, the method of analyzing. After determining the hazards with high risk, the Bayesian fault tree analysis (BFTA) method was used to determine the effective causes of events occurrence and the type of possible relationships among them.
Results: First, the phase of hazards identification, 16 Hazardous equipment were identified. Then the Risk Priority Number for the identified equipment was calculated. The results showed that the dispenser system had the highest risk priority number and was identified as the most critical equipment. According to this, the dispenser gas leakage (as the top event) was selected in this study. Then, the analysis of the dispenser gas leakage, using BFTA method identified 56 main causes, including 17 intermediate events and 39 basic events. Finally, cracking and corrosion of the dispenser hose were determined the most effective factor in the occurrence of the top event. The probability of occurrence of the top event based on FTA and BFTA analysis was calculated 9.67×10-2 and 9.11 × 10-2, respectively.
Conclusion: The result of the study that by employing the Bayesian Network, can create a useful guideline to determine the relationship between the occurrence causes of the top event. This provides an assessment of the effectiveness of preventive measures before using them.
Mohsen Mahdinia, Mostafa Mirzaei Aliabadi, Ahmad Soltanzadeh, Ali Reza Soltanian, Iraj Mohammadfam,
Volume 11, Issue 2 (6-2021)
Abstract
Introduction: Safety situation awareness is an important element affecting operator's reliability and safety performance, which is influenced by various variables. Identification of these variables and their relationship will play a major role in optimizing control measures. The present study was conducted for this purpose.
Material and Methods: This study was based on the situation awareness, expert’s opinions and use of a Fuzzy multi-criteria decision-making method. Triangular fuzzy numbers was used to quantify the experts' judgments and to reduce the errors that result from theirs’ subjective evaluation on the relationships between the variables.
Results: The results showed that the studied organizational variables together with "safety/g knowledge" and "experience in job/specific task” are the most important predictive variables of situation awareness. Among the organizational variables, "Organizational Safety Attitudes", "Safe System Design" and "Education" are the most important determinants of safety situation awareness.
Conclusion: Fuzzy logic was used to aggregate expert opinions to determine the most important variables affecting situation awareness and their cause-effect relationships. Organizational variables are the main determinants of situation awareness. To improve situation awareness, the best results are obtained by modifying effective root variables, i.e., organizational variables and some individual variables.
Monireh Khadem, Elham Kazemi Rad, Mohammad Reza Monazzam Esmaeilpoor, Maryam Mirzaei Hotkani, Sajjad Mozaffari, Amir Abbasi Garmaroudi,
Volume 12, Issue 1 (3-2022)
Abstract
Introduction: One of the most important complications of exposure to noises is changes in the gene expression patterns. Irreversible damage to the inner ear, such as noise-induced hearing loss (NIHL), is caused by tissue damage and changes in the gene expressions in the auditory system. Changes in the GJB2 gene expression pattern lead to autosomal deafness at different loci. The present study aims to evaluate the GJB2 gene expression in cochlear tissue exposed to white noise.
Material and Methods: In this study, ten male Westar rats were divided into two experimental (W1, W2) groups of six rats and a control (normal) group of four rats. Two experimental groups were exposed to constant white noise in the frequency range of 100-20000 Hz and the sound pressure level of 118-120 dB. In order to study the histology and gene expression, after a cochlea biopsy, the histological tests, RNA extraction, cDNA synthesis, and qRT-PCR analysis were performed.
Results: The results showed that the transcript level of GJB2 was significantly decreased in both experimental groups W1 and W2 by 0.02 and 0.12-fold, respectively (p <0.05). Also, the results of the histological study showed that cochlear tissue was more seriously damaged in the W1 group than W2.
Conclusion: It can be concluded that a significant reduction in the GJB2 gene expression and irrevocable damage to auditory nerve ganglion and Reissner membrane (vestibular membrane) caused changes in the gene expression patterns in cochlear tissue and developed the risk of non-syndromic sensorineural hearing.
Mostafa Mirzaei Aliabadi, Hossein Ramezani, Omid Kalatpour,
Volume 12, Issue 1 (3-2022)
Abstract
Introduction: In process industries, some of the primary events may result in secondary events in an industrial unit called the domino effect. Since refinery storage tanks are always at risk of fire and explosion, quantitative risk assessment is important in determining the severity and outcome of an accident, taking into account the effects of dominoes on the main industry, neighbors, and society and can play an important role in risk management. Therefore, the purpose of this study was to quantitatively evaluate the risk of condensate storage tanks taking into account the domino effect.
Material and Methods: The technique used in this study was Quantitative Risk Assessment (QRA), the analysis of the consequences of which was performed using PHAST (7.22) after setting goals, studying the process, identifying hazards and scenarios. Then, to determine the extent of the domino effects of the escalation vectors were matched against the threshold, and after screening, the overall vulnerability of the repositories for mapping individual risk levels was calculated.
Results: In the leakage scenario, after considering the domino effects, the risk contour 10-4 to about 250 meters and the risk contour 10-5 to about 400 meters increased. Also in the catastrophic rupture scenario, the radius of risk contour of the 10-5 increased to100 m after considering the domino effects up to around damage tank.
Conclusion: As can be deduced from the results, using this method can give a clear picture of the consequences of chain events and the probability of damage to nearby employees, equipment and neighbors, which is very important in risk, emergency and crisis management.
Ehsan Ramezanifar, Kamran Gholamizadeh, Iraj Mohammadfam, Mostafa Mirzaei Aliabadi,
Volume 13, Issue 1 (3-2023)
Abstract
Introduction: Risk assessment is a scale for predicting reliability and can manage interactions between components and process variables. Moreover, the reliability of one component or barrier affects the overall risk of the system. Being one of the most critical safety barriers of the storage tank, the failures of Fixed Foam Systems (FFS) on demand can result in severe consequences. FFS, is of grave importance in decreasing the risks associated with fires and damages.
Material and Methods: This study aims to determine the probability of root causes related to FFS failure through Fuzzy Fault Tree Analysis (FFTA) to estimate system reliability. In conventional fault tree analysis, accurate data is usually used to assess the failure probability of basic events. Therefore, the introduced approaches were employed to quantify failure probabilities and uncertainty handling. Finally, system reliability was estimated according to the failure probability of the top event.
Results: The findings showed that 13 baseline events involved FFS performance. According to the results, failures of cable path and detection system (or resistance temperature detectors), set the activation switch (multi-position) incorrectly, and foam makers not continuously running are the three most critical basic events influencing the reliability of fixed foam systems. In addition, this paper estimated the system reliability at 0.8470.
Conclusion: The results showed that the FFTA could be used in matters such as reliability evaluation failure and risk assessment using experts’ judgment. This paper can also show the adaptation of the fuzzy approach to assess the failure probability of the basic event in the fault tree analysis (FTA).
Adel Mazloumi, Ali Mohammad Mosadeghrad, Farideh Golbabaei, Mohammad Reza Monazzam Ismailpour, Sajjad Zare, Mahdi Mohammadiyan, Ramazan Mirzaei, Iraj Mohammadfam, Hassan Sadeghi Naini, Masoud Rismanchian, Yahya Rasulzadeh, Gholam Abbas Shirali, Mahmoud , Yahya Khosravi, Hamed Dehnavi, Maliheh Kolahdozi, Hanieh Ekhlas, Mirghani Seyed Somae, Solmaz Balajamadi, Mehdi Ghorsi,
Volume 13, Issue 3 (9-2023)
Abstract
Introduction: Strategic management involves determining the organization’s direction, preparing a strategic vision and mission statement, and providing the basis for growth, profitability, and production. It also includes the inclusion of employee safety and health programs throughout the organization. The existence of a strategic plan for the scientific and practical strengthening of occupational health and safety is one of the country’s academic and industrial priorities. The purpose of this study is to present a strategic plan for developing the specialized field of occupational health and safety engineering in Iran.
Material and Methods: The current study is a collaborative action research study that was conducted in 2021. The strategic planning committee consisted of 20 professors, experts, and doctoral students. Over the course of 14 weeks, they held regular weekly meetings, collected information from inside and outside the organization, analyzed the organization’s internal and external environment, and identified its strengths, weaknesses, opportunities, and threats. Based on this analysis, the committee determined the organization’s mission, perspective, values, and general and specific goals for 2021-2024. They also identified the necessary measures to achieve these goals and developed an operational plan to improve the performance of the specialized field of occupational health and safety.
Results: Conducting this applied research led to the strategy of internal and external analysis of the specialized OHS field, determining the direction of the basic strategy, mission, perspective, values, and general goals. Finally, seven specific goals and 286 actions were determined to improve the performance of OHS. The SWOT analysis of OHS’s internal and external environment identified 27 strengths, seven weaknesses, 26 opportunities, and 12 threats. According to the results of the SWOT matrix, the strategic position of the OHS field is to implement preventive strategies and maintain existing conditions.
Conclusion: This plan aligns with the 4-year OHS plan. In developing the program, attention has been paid to the documents and policies of upstream organizations. The strategic position of occupational health and safety engineering is a prudent strategy. In this situation, strategies for maintaining existing conditions can be applied. Therefore, it is suggested to reduce the weaknesses of OHS as much as possible and increase its strategic capabilities by focusing on prudent strategies. From the second year of implementing the strategic plan, the OHS field can gradually focus on developing activities.
