Showing 162 results for Mohammad
Jalil Nazari, Mohammad Dashti,
Volume 9, Issue 1 (4-2019)
Abstract
Introduction: Besides the occupational accident physical, psychological damages, and its economic losses, it can have a serious effect on the quality of working life. Therefore, the aim of this study was to investigate the effects of occupational accidents on the quality of working life and its dimensions among workers in a steel manufacturing companies.
Material and Methods: This case-control study was carried out among 100 workers (case) with an occupational accident history and 100 workers with no history of incident (control) in the production lines of a steel company during the period of 2012 to 2016. The study was conducted after matching the confounding variables such as age, work history, income level, etc. Data were collected using the NIOSH quality of work life questionnaire. For statistical analysis, SPSS 16 was used and χ2 and paired t-test statistical analysis were performed.
Results: According to the results of current study, the quality of work life average scores of the case (47.6±2.3) and control (49.5±2.3) groups was highly significant (p<0.001). Also, six out of eight dimensions of the quality of life was significantly affected by occupational accidents, but the highest and lowest influence was found on ergonomics and safety aspect, and the work and life aspect, respectively.
Conclusion: According to the result of this study, it can be concluded that occupational accidents are one of the important factors that influence the workers’ quality of work life. Therefore, quality of working life can be considered as a helpful tool in increasing job satisfaction, improving the efficiency and employability of employees and preventing accidents.
Roohollah Ghasemi, Farideh Golbabaei, Mohammad Javad Jafari, Mohammad Reza Pourmand, Sasan Rezaei, Ramin Nabizadeh, Ensieh Masoorian,
Volume 9, Issue 2 (6-2019)
Abstract
Introduction: Air pollution is now recognized as an important environmental and health concern. Biological control processes, due to their durable, cost-effective and eco-friendly, have become a good alternative to physic-chemical methods. Biotechnology is based on the activity of microorganisms.
The aim of this study was to compare the capability of Pseudomonas Putida PTCC 1694 (bacteria) and Polarotus Stratus IRAN 1781C (mushroom) in the removal of toluene from the air stream and its biodegradation under same operating conditions.
Material and Methods: To this purpose, a bio filter containing two parallel columns was designed and constructed on a laboratory scale and the experiments were carried out based on measuring the removal efficiency (RE), elimination capacity (EC) and pressure drop in these two columns. Thus, the bacteria were inoculated in one of the columns and in the other the fungus was inoculated.
Results: The bacterial testing lasted for 20 days and the fungal testing lasted for 16 days. The contaminant loading rates (LR) for bacterial and fungal bio filters were 11.65±2.26 and 11.94±2.56 g/m3.h, respectively. The results showed that the fungal bio filter was more capable of eliminating of toluene vapor than bacterial bio filter (9.65±3.53 vs 9.18±2.6 g/m3.h). However, the pressure drop in the bacterial bio filter was lower than the fungal bio filter (1±0.28 vs 1.1±0.32 cm water).
Conclusion: According to the results, fungal bio filtration appeared to be more successful than bacterial bio filtration in the removal of toluene.
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.
Ismael Javadi, Jamshid Yazdani Charati, Mahmoud Mohammadyan,
Volume 9, Issue 2 (6-2019)
Abstract
Introduction: One of the harmful pollutants in the indoor environments is particulate matters. Particles smaller than 2.5 micrometer in diameter that are suspend in the industrial environments air are the most deleterious dusts which can cause lung disease and cancer. In present study PM2.5 concentration in the fast-food shops air and its cancer risk for shop workers were assessed.
Material and Methods: In this descriptive-analytical study, all of Sari city 132 fast foods were included. Air sampling was conducted by calibrated real-time GRIMM-monitor device. Data were analyzed by using of SPSS16 and Prism6 software with T-test, Pearson correlation and descriptive statistics. Finally PM2.5 cancer risk in workers was calculated by EPA method equation.
Results: The PM2.5 concentration in shops indoor air (308.5µg/m3) significantly was higher than its concentration in outdoor air (121.98µg/m3) (p<0.05). Highest correlation was observed between indoor PM2.5 concentration with smoking (0.366) and local ventilation (-0.384) (p<0.01). The concentration PM2.5 in the indoor and the outdoor of shops was 273.55 and 86.98µg/m3 higher than acceptable level respectively. Cancer risk was 5.6 per 100 thousands and 1.97 per 10 thousands in the rest and cooking time respectively.
Conclusion: The most affective source in the elevation of PM2.5 level in shops indoor air is the cook-emitted particles. PM2.5 concentration in shops indoor and outdoor air was much higher than EPA admissible level and cancer risk for workers was unacceptable that it has required to basic solutions for air pollution control at source.
Mojtaba Zokaee, Mohsen Falahati, Hadi Asady, Masoud Rafee, Mohammad Najafi, Azam Biabani,
Volume 9, Issue 2 (6-2019)
Abstract
Introduction: Throughout the world, many efforts have been made to provide suitable tools for achieving sustainable urban development and the achievement of a sustainable city. Establishing a Health, Safety and Environment Management System (HSE-MS) is one of the tools for achieving sustainable urban development. Measuring the performance of an organization in the HSE area is a precondition for continuous improvement, which is the spirit of the new HSE management systems. Therefore, the main purpose of this research was to provide a practical model for quantitative ranking of different areas of Tehran municipality in terms of HSE performance with using of multi-criteria decision-making method.
Material and Methods: In this descriptive-applied study, after determining functional axis and performance evaluation indicators related to each of them (29 functional axis and 154 performance evaluation indicators), through designing a questionnaire and based on the views of the expert group, weight of functional axis and performance indicators were determined using a hierarchical process analysis technique.
Results: In this study, the weighted value for functional axis of the process based HSE in comparison to the result based HSE were higher. “Commitment and Leadership” and “HSE Certificate of Occupations” for the process based HSE, “Safety” and “Health” for the result based HSE, and “Economic Sustainability” and “Architecture and Urbanism” for urban management had the higher and lowest weighted values.
Conclusion: The results of assessment and validation of selected indicators and functional axis showed that in designing and determining the HSE performance assessment model of municipalities, in addition to the axises and indicators of the HSE domain, factors affecting urban management can have a significant impact on the performance of municipalities in the field of HSE.
Somayeh Farhang Dehghan, Farideh Golbabaei, Asghar Sedigh Zadeh, Hamzeh Mohammadi,
Volume 9, Issue 3 (9-2019)
Abstract
Introduction: Despite nanofibers have attracted great interests for filtering particulate matters from the air stream, fewer studies have been done on the feasibility of their use in the removal of gas pollutants, while the both pollutants are present in the most workplaces. Toluene is a toxic and mutagenic substance, and chronic exposure to its low levels can lead to a wide range of adverse health effects on people who exposed. The purpose of this study was to produce polymer /single-walled carbon nanotube hybrid nanofibers by electrospinning technique and doing plasma surface treatment and evaluating their removal efficiency of toluene from air stream.
Material and Methods: The nanofiber layers were fabricated by electrospinning solution containing polyacrylonitrile polymer (PAN) and single-walled carbon nanotube (SWNT) with a 99: 1 ratio under following conditions: applied voltage 20 kV, distance between needle and collector: 10 cm, injection rate: 1 ml / h; needle diameter: 18 gauge and drum speed ranging from 1000 to 500 rpm. The surface of the manufactured nanofibers was treated by cold-plasma with a radio frequency power supply (13.56 MHz with a power of 20 watts), argon gas and operating pressure of 0.2 torr. Test conditions was prepared according to standard ISO 10121-1: 2014, which provides a method for testing the performance of gas-phase air filter for a variety of flat sheet media. In order to measure the concentration of toluene, the First check – handheld multi gas VOC detector equipped with a PID detector was used. The morphology characteristics of the fibers was performed using the analysis of scanning electron microscope images. Infrared spectroscopy-Fourier transform was used to identify organic compounds and functional groups in nanofibers.
Results: The results of the analysis of the images showed that the mean diameter of the fiber was 169.16 ± 7.19 nm and the mean coefficient of variation was 0.23. The uniform and bead nanofibers were obtained. The thickness, porosity and air permeability coefficient of test media was 0.15 mm, 43% and 5.75 Darcy, respectively. The mean removal efficiency of PAN / SWNT nanofiber treated with plasma was 98% and the mean pressure drop was 100 Pascal. The FTIR spectrum of the test filter media showed that the peaks appearing at certain wavelengths related to the vibration of C-H aliphatic groups of C-C and C=O bands related to PAN polymer and carbon nanotubes.
Conclusion: Removal of toluene was achieved through the fabrication of PAN/SWNT hybrid nanofibers treated with plasma. Uniform nanofibers were obtained and showed the proper removal efficiency and low pressure drop.
Samaneh Salari, Maryam Farokhzad, Arash Khalili, Iraj Mohammadfam,
Volume 9, Issue 3 (9-2019)
Abstract
Introduction: Nowadays, accidents are regarded as a main risk factor for both human and economic of countries. The triggerring cause of most accident is human error. In the healthcare setting, human errors can lead to injuries and even death of patients and damage the reputation of healthcare staff. Human errors in healthcares can occur during various activities including diagnosis of a disease, drug administration, and also during the use of various appliances. Therefore, it is of critical importance to identify these errors and assess their risks. Accordingly, the main aim of the present study was to identify and assess human errors possible to occur during the use of the ventilator device in neonatal units of educational hospitals of Hamedan University of Medical Sciences.
Material and Methods: This qualitative study was conducted using PUEA technique in 2017. The required data associated with the function and operation of the ventilator were gathered by investingating documents, observing the operater while using it, and interviewing with the operator. Hierarchical task analysis (HTA) was used for determining the main tasks and subtasks performed for operating the device. The identified errors were categorized into seven groups, namely planning, functional, checking, retrieval, communication, and selection errors. The PUEA method was utilized in exploring the causes of errors, the possibility of error recovery, and associated risks.
Results: Functional error was the most prevalent one (72.7 %), whereas communication error was the least prevalent one (3.03 %). Omission and commission were the most frequent functional error. Moreover, 42.2 percent of errors had roots in lapse and slip and 12.1 percent were of knowledge-based type. Moreover, it was impossible for 79.7 percent of errors to be recovered. About 54.53 percent of errors had severe or catastrophic consequences.
Conclusion: As the risk of accidents occurring in healthcare organizations is unacceptable, it is a necessity to identify these errors and evaluate their risks. As it is costly to replace the purchased devices with less error prone devices, human error analysis should be performed in the design phase and before purchasing the devices. Moreover, errors with an unacceptable risk should be controlled based on their probable causes.
Hamed Yarmohammadi, Seyed Hassan Niksima, Soudabeh Yarmohammadi, Alireza Khammar, Hossein Marioryad, Mohsen Poursadeqiyan,
Volume 9, Issue 3 (9-2019)
Abstract
Introduction: Work-related musculoskeletal disorders (WMSDs) are any disorders or injuries to the musculoskeletal system due to working procedure or conditions. WMSDs is one of the main causes of occupational injuries and disability in advanced and developing countries. The present study was conducted to evaluate the prevalence of musculoskeletal disorders in drivers in order to achieve complete results with high statistical power, using meta-analysis method.
Material and Methods: This study is a systematic review and meta-analysis. In this study, the articles extracted from national and international databases, including Scientific Information Database (SID), Science Direct, PubMed (using the word MESH), Pre Quest, Scopus, Google Scholar, Iran Medix, SID, and MedLib. The main keywords for the search were Prevalence، Musculoskeletal and Drivers. The time for selecting articles was from 2000 to 2017. Data were analyzed using meta-analysis (random effect model). I2 and Q indexes were used to calculate heterogeneity. All statistical analysis was performed using STATA 14 software.
Results: In this study, 22 articles were entered into the meta-analysis process. The sample size was 7706 people with mean of 350 people in each study. The prevalence of musculoskeletal disorders in different organs of drivers was as follows: 26.19% (CI: 38-14.30), 18.07% (CI: 25.99-10.16), and 5.75% (CI: 8.27-3.22) in neck, shoulder, wrist / hand, and elbow respectively. The highest prevalence was related to low back pain 41.63% (confindence Interval (CI): 33.09-50.17), and the lowest prevalence was related to elbow disorder 7.45% with (CI: 95.46-9.43). The significance level was set at 0.05.
Conclusion: The results of this study show that the prevalence of pains in the back, neck, and shoulder are high among drivers. Also, due to the high prevalence of predicting the incidence of impaired driving. in order to control and reduce these disorders, appropriate design of seats and equipment of vehicles, conducting periodic examinations of drivers,performing proper exercise, and considering adequate rest time in working hours are recommended. Ergonomics and occupational health education programs are also recommended to reduce the risk of developing musculoskeletal disorders associated with driving.
Masoumeh Sadri Khanlou, Mohammadreza Monazzam, Kamal Azam, Alireza Mortezapour, Seyed Abolfazl Zakerian,
Volume 9, Issue 3 (9-2019)
Abstract
Introduction: Nearly a third of people work in jobs that use voice to be part of their work. Teachers as the largest group of professional vocal users, are at risk of vocal disorders. The aim of this study was to investigate the effect of different risk factors on vocal disorders in teachers.
Material and Methods: This is a cross-sectional and descriptive-analytic study that was conducted on 73 primary and secondary male and female school teachers in Saveh in 2017 by random sampling. The researcher-made questionnaire on risk factors affecting verbal disorders with the aim of identifying risk factors and a Voice Handicap Index (VHI) questionnaire (30 items) aimed at evaluating verbal disorders and symptom questionnaire were used in this study. All of them have been shown to be valid and reliable in previous studies. Data were analyzed using t-test and chi square statistical tests by SPSS ver.24.
Results: The reliability of the researcher-made questionnaire on the risk factors affecting vocal disorders was confirmed by Cronbach’s alpha (0.736) and its validity was confirmed by the experts regarding the adequacy of the number of questions, the lack of ambiguity and the assessment of content fitness. According to our gathered data, vocal disorders were observed in 55% of the teachers. Also the results showed the rate of vocal disorders in female teachers is far higher than male teachers. Functional disturbance of vocal cords and allergy as general risk factors, teaching tools and poor air quality as environmental risk factors and inadequate vocal rest and job stress as occupational risk factors contributed to increasing vocal disorders in teachers. Among the symptom associated with verbal disorders in teachers, vocal fatigue and hoarseness were more common in comparison with other symptoms.
Conclusion: Due to the prevalence of vocal disorders in half of the teachers and the impact of general, environmental and occupational risk factors, it is necessary to identify and control the risk factors of vocal disorders in teachers. It can also be concluded that teachers can enjoy a healthy voice by considering the principles of ergonomics and occupational health.
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.
Ahmad Soltanzadeh, Hamidreza Heidari, Heidar Mohammad, Abolfazl Mohammadbeigi, Vali Sarsangi, Milad Darakhshan Jazari,
Volume 9, Issue 4 (12-2019)
Abstract
Introduction: The causal analysis of occupational accidents’ severity in the chemical industries may improve safety design programs in these industries. This comprehensive study was implemented to analyze the factors affecting occupational accidents’ severity in the chemical industries.
Methods and Materials: An analytical study was conducted in 22 chemical industries during 2016-2017. The study data included 41 independent factors and 872 accidents in a ten-year period (2006-2015) as a dependent variable. Feature selection algorithm and multiplied linear regression techniques were used to analyze this study.
Results: Accident severity rate mean was calculated 214.63 ± 145.12. The results of feature selection showed that 30 factors had high impacts on the severity of accidents. In addition, based on regression analysis, the severity of accidents in the chemical industries was affected by 22 individuals, organizational, HSE training, risk management, unsafe conditions and unsafe acts, as well as accident types (p<0.05).
Conclusion: The findings of this study confirmed that accidents’ severity in the chemical industry followed the multi-factorial theory. In addition, the main finding of this study indicated that the combination of features selection algorithm and multiple linear regression methods can be useful and applicable for comprehensive analysis of accidents and other HSE data.
Roohalah Hajizadeh, Ali Khavanin, Ahmad Jonidi Jafari, Mohammad Barmar, Somayeh Farhang Dehghan,
Volume 9, Issue 4 (12-2019)
Abstract
Introduction: Nowadays multiple techniques have been developed to noise control. One the most important way is the control based on sound absorption and insulation. The purpose of current study was to improve the acoustic properties of soft polyurethane foam regarding combined sound absorption and insulation characteristics.
Materials and Methods: Polyacrylonitrile and polyvinylidine fluoride nanofibers are fabricated using solution electrospinning technique. Nano-clay particles (montmorillonite, 1-2 nm in diameter) were purchased from Sigma-Aldrich, Inc. Experimental design was prepared using Design-Expert ver.7 software. The 50 samples of nanocomposites were fabricated on the basis of experimental run. The measurement of sound transmission loss and the absorption coefficient was conducted using BSWA SW477 550005 Impedance Tubes according to the standard ASTM E2611-09 and ISO10534-2, techniques. Response surface methodology (RSM) with central composite design (CCD) was applied to optimize the conditions to produce nanocomposites for each frequency range.
Results: The polymer nanocomposites had the higher combined sound transmission loss and the absorption coefficient than pure polyurethane foam. Their combined transmission loss and the absorption coefficient in the low, middle and high frequency range was 02.02, 1.91 and 2.53 times higher than the pure polymer. The combined transmission loss and the absorption coefficient in all frequency ranges have been increased by increasing the thickness of the composites and air gap. At a thickness of 2 cm, the combined composites, sound transmission loss and the absorption coefficient increased with the increase of content of both nanofibers. The highest combined transmission loss and the absorption coefficient was observed when mass fraction of nanofibers was in at its maximum level.
Conclusion: This study showed that the adding nano-clay particles, polyacrylonitrile and polyvinylidine fluoride nanofibers to polyurethane foam can lead to increased sound transmission loss and the absorption coefficient. The obtained optimized nanocomposite can be applied to noise control where requiring the absorption as well as reduction of sound transmission.
Hojatolla Kakaei, Mojtaba Beygzadeh, Farideh Golbabaei, Mohammad Reza Ganjali, Mehdi Jahangiri, Sayed Jamaleddin Shahtaheri,
Volume 9, Issue 4 (12-2019)
Abstract
Introduction: Hydrogen sulfide is one of the most important impurities in natural gas. Due to the fact that this gas is hazardous, toxic, corrosive and volatile, therefore, the removal of hydrogen sulfide has been studied using several methods. One of the most known procedures is the adsorption process. In the present study, activated carbon and activated carbon-based composite scaffolds (MOF-5) were used as a cartridge mask to remove hydrogen sulfide from respiratory air.
Methods and Materials: First, activated carbon (AC) was converted to powder form by ball mill, and AC / MOF-5 composite with 10%, 25%, and 40% MOF-5 to AC was synthesized from the MOF-5 metal-organic scaffold. Then, the rates of adsorption and breakthrough time using a designed setup were tested in two ranges of temperatures, humidities and concentrations. XRD, SEM and BET were used to determine the properties of composite absorbents. The Aeroqual S500 Direct-reading sensor with 0.01 ppm accuracy was used to measure the exact amount of hydrogen sulfide gas.
Results: The AC/MOF-5 composite showed higher adsorption and breakthrough time compare to the other adsorbents. The Specific surface area (BET), average pore diameter, and total pore volume of the adsorbent were 814 m2 /g, 1.6795 nm, and 0.342 cm3 /g, respectively. The isotherm diagram showed that, according to IUPAC, most of the pore size of this adsorbent was classified in the micro-porous group. The maximum adsorption (mg/gS) and breakthrough time (min) were related to AC/MOF-5(40 Wt. %) adsorbent with 60.41 mg/gS (SD = 1.08) and 56.26 min (SD =2.38) at a temperature of 15 ° C, a concentration of 9.88 ppm (SD = 0.70), a moisture content of 51.06% (SD = 0.15) and a pressure drop of 51.34 mm water. By adding more than 25% MOF-5 metal-metal scaffold to activated carbon, the amount of adsorption, breakthrough time and pressure drop were increased.
Conclusion: AC / MOF-5 composite adsorbent due to its porous structure, high specific surface area, and most importantly, having Zn-O-C groups increased the adsorption rate as well as the pollutant Breakthrough time. However, it showed a relatively higher pressure drop than commercial activated carbon (AC).
Mahsa Azarnia Ghavam, Adel Mazloumi, Mohammad Reza Hosseini,
Volume 9, Issue 4 (12-2019)
Abstract
Background: Industrial incidents are one of the major problems of today's societies. Studies in this field show that the main and most important cause of error occurrence is human factor. Therefore, the aim of this study was to identify and evaluate the risk of human error in the activities related to the operation of electrical installations of the Tehran Province Electricity Distribution Company.
Methods: This study is a qualitative and cross-sectional research was conducted by direct observation of the activities and documents, interview. Tasks and subtasks were selected and analyzed using Hierarchical task Analysis, (HTA).The results were presented in the form of HTA. Finally, according to the instructions of SHERPA, the relevant worksheet was completed.
Results: The analysis of SHERPA worksheets showed that a total of 3399 errors were detected for 759 tasks as 39.57% of them were action errors, 32.4% review type, 7.32% recovery type, 19.64% communication type and 1.80% were selective errors. According to the results of risk assessment, 12.47% of the errors were unacceptable risks level, 59.57% were undesirable, and 20.2% were acceptable risks but need to be revised and the rest, 7.33% acceptable with no need for revision or safe ones.
Conclusion: According to the results, the most common type of error was action errors and in order to reduce this type of errors, using necessary corrective measures such as proper selection of people for occupations, training, monitoring, using smart machines, using tag out systems and checking at the suitable time and updating the instructions would be useful and effective countermeasures.
Hasti Borgheipour, Ghazaleh Monazami Tehrani, Shahriyar Madadi, Iraj Mohammadfam,
Volume 10, Issue 1 (3-2020)
Abstract
Introduction: Cranes are of the major causes of accidents in the construction industries. As human error mostly causes crane accidents, this study aims to investigate the human errors of tower crane operators in the construction projects using SHERPA and CREAM techniques.
Material and Method: In this research, first, all of the tasks of the tower crane operator were identified and analyzed. Then, adopting SHERPA technique, probable operator errors were identified in each task and the control modes and error probability were determined by CREAM technique. Finally, all the human errors risks were assessed and the actions for risk control were defined to control them in the acceptable level.
Result: According to the SHERPA technique, 148 errors were identified in the crane operator tasks. The human error assessment showed that monitoring the anti-collision system with the risk probability of 0.0003 has the highest control factor, while monitoring the existing guards with the risk probability of 0.056 has the lowest control factor. Also, the important tasks with high human errors were monitoring the guards with the cognitive risk probability of 0.07 and the tasks with cognitive risk probability of 0.05.
Conclusion: The findings in this study indicated that using complementary qualitative and quantitative methods can provide identification and prioritization of identified errors. This can help the organization to allocate limited organizational resources to control unacceptable risks and increase the efficiency and effectiveness eventually.
Hasan Iravani, Mohammad Javad Jafari, Rezvan Zendehdel, Soheila Khodakarim, Athena Rafieepour,
Volume 10, Issue 1 (3-2020)
Abstract
Introduction: Hydrogen sulfide (H2S) is a toxic gas that has adverse effects on human health and equipment. One of the methods for eliminating of H2S gas is the use of adsorbent substrate. In this study, the effect of adding iron oxides including ferric (Fe2O3) and magnetite (Fe3O4) nanoparticles to ZSM-5 zeolite substrate was investigated on the efficiency of H2S elimination from the air stream.
Methods: In this study, Fe2O3 and Fe3O4 nanoparticles were impregnated in ZSM-5 zeolite in two weight ratios of 3% and 5%. The structural properties of the substrate were studied using XRD, BET and SEM. Then, the efficiency of substrate in removing H2S from air was studied while H2S gas was injected in to a pilot setup, in concentrations of 30, 60, 90 and 120 ppm at three bed temperatures of 100, 200 and 300 o C.
Results: The accuracy of combination and the morphology of inoculated zeolite was confirmed using XRD and SEM. The BET test also showed that the loading of iron oxide nanoparticles on the substrate educed the substrate surface area. The results revealed that increasing the percentage of nanoparticles and increasing the temperature from 100 ° C to 300 ° C increase the time of breakthrough point. The maximum adsorption capacity was obtained equal to 44.449 (mgH2S/g zeolite) for ZSM-5/Fe3O4-5% substrate at 120 ppm concentration.
Conclusion: Iron oxide nanoparticles inoculated in ZSM-5 zeolite substrate increase the capability of eliminating of H2S gas at high temperatures and therefore can be used as a suitable method for the elimination of similar pollutants.
Farideh Golbabaei, Rezvan Abedinlou, Nazanin Fekri, Ashkan Shapasandi, Hamzeh Mohammadi,
Volume 10, Issue 1 (3-2020)
Abstract
Introduction: Among the pollutants present in the ceramic and tile industry, silica dust is particularly important, and many studies have investigated the effect of this material on the respiratory system. Many occupational exposures may result in a decrease in spirometric parameters.
Materials and Methods: In the present study, totally, 120 male workers and employees of the factory, who had work experience of over 5 years and were not changed during the study, were included. Demographic information, including age, height, weight, work experience, smoking status and spirometric indices, were extracted from the medical records of the workers from different groups for 5 consecutive years. All spirometry tests were performed using the FUKUDA ST 300 digital spirometer (Italy) calibrated once a year. The generalized Estimation Equation (GEE) method was used to study the trend of changes in each of the spirometric indices more accurately. Research related data were analyzed using SPSS software version 23.
Results: The trend of changes was only significant for the FEV1 / FVC and FEF indices; for other indexes, the trend of changes was only observed in some years. The trend of changes was not significant for the FEV1 index, but smoking had a significant effect on the changes in this index. So, the level of this index was lower for cigarette smokers.
Conclusion: In this study, a clear downward trend was not found in the spirometric indices over 5 years, and only the FEF1 / FVC and FEF 2575% indices markedly were reduced in some occupational units, but due to the decline in some indices as well as proving the bad effect of Silica dust and other compounds on the respiratory system, there was an urgent need to implement management and engineering controls and protect the workers in the workplaces
Vahid Gharibi, Abolfazl Mohammadbeigi, Mahdi Asadi- Ghalhari, Hamidreza Heidari,
Volume 10, Issue 1 (3-2020)
Abstract
Introduction: This study was designed with the main purpose of examining the compatibility of the two indicators of wet bulb globe temperature (WBGT) and predicted thermal strain (PHS) in assessing the environmental conditions and the heat load imposed on the subjects.
Method: In this cross-sectional study, 163 bakers were included in the study. Thermal stress was determined using the WBGT and PHS. At the same time, physiological responses of subjects were recorded, including tympanic temperature, heart rate and mean skin temperature. Finally, the predicted heat strain was evaluated and compared with actual values.
Results: Based on the results, the WBGT index is accompanied with an underestimation and PHS with an overestimation, compared to the tympanic temperature. In addition, the WBGT index with the core temperature and the predicted rectal temperature component of the PHS index are the most consistent (kappa value of 0.614 and 0.66, respectively). While the Kappa value is between the amount of water lost and the WBGT index, it indicates a mismatch (Kappa = 0.339).
Conclusion: The prediction of heat strains only based on the PHS index cannot reflect the actual heat load on individuals in thermal environments such as bakeries and it is associated with an overestimation. On the other words, this indicator is more suitable for indoor thermal environments, with minimal variation in individual and environmental factors affecting thermal stress
Shahram Vosoughi, Mohammad Hossein Chalak, Sajjad Rostamzadeh, Manouchehr Jahanpanah, Hossein Ebrahimi,
Volume 10, Issue 2 (5-2020)
Abstract
Introduction: Fall from height is one of the main causes of death in the construction workers. Therefore, this study aimed to identify and prioritize the factors affecting falls from height accidents in construction industry.
Material and method: A descriptive-analytical study was conducted on five constructional projects in Pars Jonoobi industrial region, Iran. All of the reported events from 2011 to 2015 were investigated and 74 out of 377 occupational accidents were considered as falls from height accidents. The identified factors and sub-factors were divided into 3 main factors including individual, organizational and environmental factors and 14 sub-factors based on the experts’ opinion. Then, AHP method was used to determine and prioritize of the factors and sub-factors.
Results: The results of hierarchical analysis of fall from height accidents causes showed that environmental, individual, and organizational factors with weights of 0.359, 0.351, and 0.290 were in the first, second, third priorities, respectively. Meanwhile, among all examined sub-factors, work platform elevation, mental/ occupational stresses and safety culture had the highest priority.
Conclusion: Paying attention to the strategies that enhance the safety culture of employees and reduce their occupational stress levels in the workplace can be very effective in preventing of fall from height accidents.
Masoud Mohammadi, Aliakbar Vaisi-Raygani, Rostam Jalali, Nader Salari,
Volume 10, Issue 2 (5-2020)
Abstract
Introduction: One of the most common psychiatric disorders in nurses is job stress. Regarding the inconsistency of the studies conducted in nurses working in Iran, the present structured review and meta- analysis study was conducted to determine the prevalence of job stress in nurses working in Iranian hospitals.
Materials and Methods: The present study is a systematic review and meta-analysis conducted during 2001-2017. Articles related to job stress were obtained by searching SID, MEDLINE (PubMed), Science direct, and Google Scholar databases, and data were analyzed using Comprehensive Meta-Analysis software.
Results: Having investigated 17 studies, the overall prevalence of Job stress in nurses working in Iranian hospitals was obtained 60% (48.1% - 70.7%: 95% confidence), meta-regression test was conducted to investigate the heterogeneity of meta-analysis results. It was reported that increasing sample size decreases the prevalence of Job stress (P <0.05).
Conclusion: Regarding the high prevalence of job stress among nurses working in Iranian hospitals, health policymakers have to take effective measures to remove and reduce the stress causes in nurses to reduce the prevalence of stress in nurses and enhance work efficiency.
