Showing 177 results for Mohammad
Milad Abbasi, Mehran Pourhossein, Hamzeh Mohammadi, Farideh Golbabaei,
Volume 10, Issue 3 (8-2020)
Abstract
Introduction: Many studies have been carried out on the effects of heat stress on cognitive functions, but the results are contradictory. Therefore, this study was conducted to review the effect of heat stress on cognitive functions.
Material and method: In this study, all English articles conducted on effect of heat stress on cognitive, perceptual, and psychomotor functions from 1970 to 2018 were reviewed. For this, articles with keywords such as heat strain, heat stress, cognitive function, memory, comprehension, psychomotor, reaction time, mental performance, mood, mental response, error, task performance, fatigue, alertness, hyperthermia, and heat exhaustion in the Scopus, Web of Science, Science Direct, Pub Med, Springer, Wiley Online Library and ProQuest databases were searched. Out of 157 retrieved articles, 39 articles were finally reviewed according to the inclusion criteria.
Results: Out of 157 retrieved articles related to the topic, according to the inclusion criteria, 39 articles were finally considered for review. Among this articles, 9 (%23) articles were published before 2000 and 30 (%77) after 2000. Two articles were in athletes, four articles (%10.2) in workers, four articles (%10.2) in students, four articles (%10.2) in military soldiers and twenty-five articles (%64.2) were conducted in ordinary people.Based on the results, heat stress was identified as a detrimental factor for decreased cognitive functions such as reading comprehension, memory, focus, mathematical processing, tracking test, reaction time, perception and decoding text and numeric messages, visual alertness, mental computing, text reading , hidden figures test and verbal fluency.
Conclusion: Based on the results of these studies, heat stress has been introduced as a detrimental factor for disrupting cognitive functions, but conclusion based on the results of studies is a systematic method is difficult because many confounding variables such as type of work, exposure time, skill and adaptation plays a big role.
Shahram Vosoughi, Kourosh Sarvari, Mohammad Hossein Chalak, Mohammad Khandan, Sajjad Rostamzadeh,
Volume 10, Issue 3 (8-2020)
Abstract
Introduction: Safety is a significant part of the public transportation. Suitable safety climate has a positive effect on safety performance and reduces accidents rate. The aim of this study was investigating safety climate status of Tehran subway drivers in 2013.
Material and method: The present study was a descriptive and cross-sectional study. In this study, statistical population was all drivers of 1, 2 and 4 lines of Tehran Urban & Suburban Railway Operation company. Also, a questionnaire arranged by one of our researcher was used to collect demographics data of subjects. Safety climate was also investigated using standard Vinod Kumar's questionnaire. Data were analyzed by descriptive statistics and T-Student and ANOVA tests using SPSS21 software.
Results: Overall, 293 questionnaires were analyzed. Among the participants, 38.8% were line 1 derivers, 31.1% line 2 drivers and 33.1% line 4 drivers. The mean and standard deviation of the safety climate was 146.53±49.44, which is less than 147 (median). The results indicated that safety climate had a relation with the age group and education levels (P<0.01), while had no significant relationship with the deriving experience, and also marital status (P>0.05).
Conclusion: Safety climate status among subway drivers is not desirable. Among the various factors, commitment and performance of management in the safety area had the weakest status. Strengthening the structure of the health, Safety and Environment (HSE) management system in the Tehran Urban and Suburban Railway Operation company can enhance the level of safety climate among staff of this organization.
Sahel Khakkar, Mohammad Ranjbarian, Soheila Khodakarim, Mostafa Pouyakian,
Volume 10, Issue 3 (8-2020)
Abstract
Introduction: Commercial complexes are one of the most prestigious public and city-centered areas in terms of urban safety and passive defense. The purpose of this study was to determine the fire safety risk score of commercial complexes and its related factors.
Material and method: The commercial complexes of area 1 of District 12 of Tehran were studied. The characteristics of the complexes, including construction, height, activity, Occupancy Coefficient and etc in each complex were collected. fire risk assessment was performed using NFPA101 standard and CFSES software in three areas of control, Egress and general safety. In SPSS software version 21, linear regression and ANOVA tests were used to determine the relationship between variables.
Results: Of the 79 commercial complexes studied, only 8 in control area and 4 in general area achieved acceptable risk level. None of them achieved an acceptable score in the Egress. According to the results, there was no significant relationship between risk levels and height, type and activity Coefficient of them(p>0.05). However, between Occupancy Coefficient of complexes with fire safety risk levels of control(p<0.001) and general(p= 0.013) and between construction with all risk levels ((pEgress= 0.004), (pControl & pGeneral<0.001)) There was a significant relationship.
Conclusion: The results showed the current situation of the studied commercial complexes is prone to cause a disaster in the 12th district of Tehran; Using the results of this study in urban planning and cross-sectoral communication to improve the safety of commercial complexes in the region is suggested.
Abdolsamad Ahmadvand, Reza Arjmandi, Ali Mohammadi, Adel Mazloumi, Seyed Alireza Mirzahosseini,
Volume 10, Issue 4 (11-2020)
Abstract
Introduction: Assessing health, safety, and environment (HSE) performance based on up-to-date analytical models like resilience engineering, especially in automobile manufacturing companies, affected by the trilogy of HSE factors and functions, is of crucial importance. Therefore, this study was to review the factors effectively involved in HSE management performance assessment based on resilience engineering in automobile manufacturing industries.
Material and Methods: To collect and classify the data, many relevant articles and procedures published in journals or presented at seminars were researched and cited. In this study, reliable online databases, including Google Scholar, Web of Science, Scopus, and PubMed were searched to meet this purpose. Other databases in Farsi such as Magiran, CIVILICA, and Scientific Information Database (SID) were also employed. Accordingly, a total number of 211 articles were extracted and filtered in terms of content and topic by a team of four HSE senior experts, whereby irrelevant studies were deleted, the full text of each relevant article was more closely considered, and finally 18 studies were selected and thoroughly examined.
Results: The findings from these 18 articles revealed that the HSE would be influenced in various industries by factors such as organizational culture, learning and training, political-economic variables, workforce qualifications and skills, strategic and large-scale programs of organization plus its assets and financial resources. In automobile manufacturing industries as well, circumstances might emerge because of some extra-organizational threats and intra-organizational weaknesses, whereby the appearance of deficiencies in various processes and even the functions of the HSE as a whole would be impaired. Of the many external factors, one could mention economic sanctions, large-scale socioeconomic problems, and lack of materials and production equipment. The internal problems would also range from production reduction and cuts in budgets earmarked for different management departments to a rise in the number of accidents and diseases, soaring medical treatment costs, as well as growing expectations in employees, which together impact the HSE management performance.
Conclusion: Regarding the studies conducted on various models presented so far in the area of resilience, it was concluded that the HSE performance of organizations intended to prevent and control risk factors were by no means distinct from other management factors and strategic decision-making in an organization. Rather, the HSE indicators could be impacted by many extra- and intra-organizational factors. Based on the models surveyed, it would be essential to consider the concept of resilience in HSE management. The reason for this is that the idea of the HSE would appear to be an issue of less virtue and importance in various stages and situations in the lifecycle of an organization, which is not consistent with the HSE management system and does not keep pace with the influencing factors.
Marziye Pirani, Mohammad Raza Monazzam, Seyed Qasem Pourjandaghi,
Volume 11, Issue 1 (3-2021)
Abstract
Introduction: Reducing noise pollution has become an essential issue due to the increase in public concern and also social demands for a better lifestyle. Using sound absorption materials is a preferred method to reduce the noise pollution. Undesirable properties of pure polyurethane such as poor absorption of mechanical energy in narrow frequency ranges can be improved by providing polymeric nanocomposites. The main purpose of this study is to synthesize the polyurethane nanocomposite foams in order to improve its acoustic properties.
Material and Methods: At the first steage, pure polyurethane foam was synthesized using the pre-polymer method. Afterwards, nanocomposite foams were synthesized with different mass fractions of Nano silica. The cellular morphology of prepared nanocomposite foams was investigated by scanning electron microscopy (SEM (.Utilizing a two-microphone impedance tube, sound absorption coefficient (α) was calculated in the frequency ranges of 100 Hz to 1600 Hz in order to investigate the acoustic properties of the new absorbant.
Results: According to the microscopic investigations, morphology of the cells changed after adding silica nanoparticles. Also, the cell sizes were observed to be decreased by increasing the amount of silica nanoparticles. Furthermore, the acoustic analysis of nanocomposite foams indicated that the sound absorption increased by enhancing the load of silica nanoparticles.
Conclusion: In the current study, the effect of silica nanoparticles additive amount on acoustic properties of the polyurethane-based nanocomposite was investigated. Our findings depicted that the polyurethane-based nanocomposites were able to promote the sound absorption coefficient.
Fatemeh Fasih-Ramandi, Asghar Sadigzadeh, Mohammad-Javad Jafari, Soheila Khodakarim,
Volume 11, Issue 1 (3-2021)
Abstract
Introduction: Determining the size distribution of the particles for assessing their effects on human health and their control mechanisms is very effective. One of the most important equipment used in determining particle size distribution is the DMA. In this study, in addition to the design and construction of a DMA, the size distribution measurement of aerosol particles was carried out.
Material and Methods: In this experimental-laboratory study, according to the theoretical principles, the geometric dimensions and operating conditions of the DMA were determined by Fortran programs. The design of the technical drawing of the DMA was done using the Salidworks-2017 software. The DMA designing was performed by studying the size distribution of 12 ranges of DOP particles in 15 voltages.
Results: The results of applying different voltages to the DMA showed that one range of particles size had the highest number of particles in the output of the DMA at each voltage. As the number of particles with the size of 0.26-0.3 µm at 3500 volts and those larger than 2 µm at 9000 volts is the highest at the output of the DMA.
Conclusion: DMA systems are a robust tool in determining the particle size distribution. As by knowing the required voltage to separate a specific size of the particles, the DMA will be able to specify the spectrum of unknown particles.
Azam Biabani, Mohsen Falahati, Iraj Alimohammadi, Mojtaba Zokaei, Hamed Jalilian, Ali Dehghani, Mohammad Najafi Majareh,
Volume 11, Issue 1 (3-2021)
Abstract
Introduction: Determining methods for assessing heat stress in different work environments is one of the major challenges for researchers in this field. The purpose of this study was to validate WBGT index and heat pressure assessment (HPA) by some physiological responses in Iranian South Oil Company.
Material and Methods: This descriptive-analytical study was carried out on 154 employees of Kharg, Asalouyeh and Mahshahr oil terminals recruited from three different working conditions including indoor, outdoor and rest environments in the summer. The amount of heat stress in the workplace was evaluated by WBGT index HPA method. To meet this purpose, the environmental parameters i.e., temperature, wet temperature, radiation temperature, relative humidity, water vapor pressure and air flow rate were determined. In addition to the direct reading method by the WBGT meter, ISO 7243 was used to calculate the WBGT index. In order to validate the heat stress indicators, physiological parameters of oral temperature, tympanic temperature and work metabolism were measured.
Results: The results of paired sample t-test showed a significant difference between WBGT index and HPA in indoor and outdoor environment (P<0.05). Moreover, there was a significant difference between the physiological indices of oral and tympanic temperatures and work metabolism in the indoor and outdoor environment (P<0.05). Furthermore, the correlation test was significant between WBGT index as an independent variable and HPA as a dependent variable (P<0.05) and showed a high correlation (R2=0.914) between WBGT index with oral temperature and tympanic temperature . Also, the rate of work metabolism was significantly related with the aforementioned parameters (P<0.05) and was equal to R2=0.423, R2=0.335, R2=0.552, respectively. The correlations were also significant between HPA with Oral temperature, tympanic temperature and work metabolism (P<0.05)and were equal to R2=0.632, R2=0.605, R2=0.557, respectively. The results showed also that the correlation rate between the HPA with physiological parameters is stronger than that between physiological parameters with the WBGT index.
Conclusion: This study showed that WBGT and HPA methods are useful for assessing the heat stress of Iranian South Oil Company. Also, the HPA method is more reliable for assessing heat stress in these regions.
Rabee Menhaje-Bena, Mohammad Kazem Koohi, Soroush Modabberi, Mmahmood Ghazi Khansari, Shahnaz Bakand,
Volume 11, Issue 1 (3-2021)
Abstract
Introduction: Particulate matter (PM) is known as the most common cause of air pollution in the world. Activities of sand quarries are known as one of the emission sources in Tehran. This study aimed at investigating the geological and environmental factors of airborne particles in an active quarry in the west of Tehran.
Material and Methods: Three methods of dust sampling were used. totally, 32 samples were analyzed by Scanning Electron Microscope-Energy Dispersive X-ray (SEM-EDX). The data were analyzed through Principal Component Analysis (PCA), Enrichment Factor (EF) and Geo-accumulation Index (Igeo).
Results: The results showed the presence of Si, Ca, Al, Na, Fe, K, Zn, Pb, P, S, Mg, Cu, Ti, Mn, Cl and V in dust of the quarry. Also, the elements of Mn, V, Zn, Cu and Pb were shown to have moderate to extremely enrichment and contamination from anthropogenic origin. The silicon and potassium were found to have a natural source originated from igneous and alluvial rocks.
Conclusion: In this study, it was shown that fugitive dust generated from sand quarries and related activities have higher concentration of elements than those in the Earth crust due to anthropogenic activities. Further studies on transfer of fugitive dust from sand and gravel quarries to Tehran and assessment of its health impact are suggested.
Aysa Ghasemi Koozekonan, Mohammad Reza Monazzam Esmaeilpour, Saba Kalantary, Ali Karimi, Kamal Azam, Farideh Golbabaei,
Volume 11, Issue 1 (3-2021)
Abstract
Introduction: The skin, can be exposed to harmful factors like ultraviolet radiation (UV). Exposure to this physical hazardous agent could be contributed to pigmentation, erythemas, early aging, skin cancer, and DNA damage. The aim of this study, therefore, was to fabricate the polyacrylonitrile (PAN) nanofibers with the UV protection property by the use of various concentrations of titanium dioxide (TiO2) nanoparticles.
Material and Methods: The PAN nanofibers (10%wt) containing 0, 1, 5, 10 and 15% wt of TiO2 nanoparticles were produced using electrospinning method. The morphological propertis of nanofibers were studied by scanning electron microscopy (SEM) and the functional groups were investigated by Fourier transform infrared spectrophotometer (FTIR). The UV protection property of nanofibers was studied by measuring UV transmittance as well as calculating UV protection factor (UPF).
Results: The results showed that the diameter and morphological characteristics of nanofibers are different at various concentrations of TiO2 and increasing the concentration of TiO2 has resulted to an increase in nanofibers diameter. The analysis of FTIR results showed that TiO2 nanoparticles have been successfully loaded on nanofibers for UV protection purposes. The findings clarified that nanofibers loaded with TiO2 could increase the UV protection property up to 15%.
Conclusion: Totally, our findings show the successful fabrication of UV-protective nano webs using TiO2 nanoparticles. the new combination used in nano matcould protect employees from UV radiation.
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.
Mohammad Ebrahimi, Mahmood Reza Azgahini, Jalil Nazari, Abdol Rasoul Safiyan,
Volume 11, Issue 2 (6-2021)
Abstract
Introduction: Carpet-weaving is one of the hard and harmful jobs, which affect the health of the workforce. Based on the previously conducted research, musculoskeletal disorders in the neck, shoulder, and lower back regions are common among carpet weavers. This study conducted to investigate the muscle activity of the shoulder and lower back regions in carpet weavers during work on traditional and ergonomic workstations by surface electromyography.
Material and Methods: 18 experienced male weavers with a mean age of 38 and mean weaving experience of 11.1 years participated in this study. Each weaver took part in two trails of 120 min. Surface EMG signal recordings were done during weaving for four muscles (bilaterally in trapezius and erector spine). The RMS and MPF values were extracted from the raw EMG signal to estimate muscle activity and fatigue.
Results: The results obtained from the 5-time intervals indicated the lowered MPF in the ergonomic workstation compared to the traditional one. The result of the mean RMS in most of the recorded times was lower in the ergonomic workstation than that in the traditional one.
Conclusion: According to the results of the study, the modified workstation was well-suited for trapezius muscles, and the traditional one had an advantage for the erector spine muscles.
Mehdi Amirkhani, Farbod Kouhpaye, Mohammad Reza Rajabi, Majid Najafi Kalyani, Javad Salami,
Volume 11, Issue 2 (6-2021)
Abstract
Introduction: Occupational injuries are considered as the most common work-related risk factors among the medical sciences students. Medical sciences students are mostly exposed to needle stick injuries and sharp objects when training in the clinical environment due to lack of enough experience. This study aimed at investigating the frequency of these injuries and the related causes of its occurrence among the students in various disciplines of medical sciences.
Material and Methods: This descriptive cross-sectional study was performed on the students of Fasa University of Medical Sciences in 2017. All medical, nursing, operating room, anesthesiology, and medical emergencies students were recruited to this stud using census method. Then, a questionnaire was distributed among them. The data collection tool in this study was a researcher-made questionnaire consisting of two parts of demographic characteristics and the related causes of the occurrence of injuries. After completing the questionnaire by the students, data management and analysis was performed using statistical tests and SPSS 22.
Results: The results of this study showed that 74 students (24.3%) had reported being injured caused by sharp objects at least once over their studying period of time. Twenty-six students (35.1%) described their carelessness as the main cause of the injuries. Intramuscular injection with 20 cases (27%) was the most important procedure leading to needle stick exposure. Chi-square statistical test showed that there was a statistically significant difference between the frequency of injuries caused by sharp objects and gender, so that the exposure frequency was more reported by the male students (P <0.05).
Conclusion: The results showed that injuries caused by needle stick and sharp objects are high in medical sciences students. Due to this high prevalence, in educational programs, and especially in the clinical setting, accurate and precise training and arrangements are highl recommended with the emphasis on safety measures. Also, the use of personal protective equipment (PPE), before and during working with the patient is essential for medical sciences students. In addition, due to disability of injured students, making a planning program for training them about the potential risk of these injuries is necessary.
Razieh Janizadeh, Ali Kavanin, Mohammad Sharif Hosseini, Elham Yahyaei, Atefeh Mohammadi Nejad, Hasan Asilian Mahabadi,
Volume 11, Issue 2 (6-2021)
Abstract
Introduction: Regarding the daily growth of Volatile Organic Compounds (VOCs) application in a vast variety of industries which also contributed to their adverse effects, different methods were used for controlling their emission. One of the most effective methods for this purpose, is a combination of cold plasma and catalyst or photo catalyst. In this study, the effectiveness of the HZSM-5/ Tio2 for Toluene treatment removal was investigated
Material and Methods: HZSM-5 zeolite, and Tio2 in 3 and 8 weight percent were used for photo catalyst preparation. The TiO2 particles were coated on the zeolite by impregnation method. X-Ray Diffraction, Scanning Electron Microscope and Brunauer Emmett Teller tests were used for the identification of photo catalyst structural properties. Toluene vapors with 58±2 PPM concentrations were produced in ambient condition including the room pressure and temperature by a dynamic system and introduced to a reactor included 1 gr of the photo catalyst. Vapors were passed from the reactor continuously with a rate of 0.5 liter per minute. Removal efficiency in three different states; plasma only, plasma /HZSM-5/TiO2 3%tw, and plasma/HZSM-5/TiO2 8% tw were assessed at the voltages of 4000 to 8000.
Results: In the current study, the removal efficiency of toluene vapors were 44.9, 75.36 and 66.68 percent for plasma, plasma /HZSM-5/TiO2 3%tw and plasma/HZSM-5/TiO2 8% tw, respectively. Photo catalyst with 3 weight percent showed the best removal efficiency. In all tests, the removal efficiency increased when the voltage increased and in 7000 volts it reached the maximum level. Therefore, adding photo catalyst to the plasma caused significant improvement in removal efficiency. Also, HZSM-5/TiO2 3% tw showed the best performance for toluene vapors removal.
Conclusion: According to the current study findings, using this combination in an industrial environment can be an effective way for Toluene vapors without the need for high temperatures. This combination can be proposed for other VOCs.
Sepideh Keyvani, Mohammadreza Monazzam Esmaielpour, Fatemeh Fasih-Ramandi, Akbar Ahmadi Asour, Malihe Kolahdouzi, Zahra Hashemi,
Volume 11, Issue 3 (9-2021)
Abstract
Introduction: The acoustic performance of natural fiber adsorbents has been investigated in numerous studies. A part of these materials show a poor adsorption within the frequency range of less than 1000 Hz. In the present study, attempts were made to investigate the effect of layout sequence of double-layered composites consisting of natural and synthetic fibers on improving the acoustic adsorption coefficient of natural fiber in the low-frequency range (63 to 1000 Hz) using the numerical finite element method.
Material and Methods: In this study, the finite element method and the Johnson-Champoux-Allard model in COMSOL software version 5.3a were used to investigate the acoustic performance of the double-layered composites consisting of natural and synthetic adsorbents. The acoustic absorbers under study included date palm fiber, polyurethane foam and cellular rubber. Each double-layered composite included a date palm fiber with 10mm in thickness and a synthetic adsorbent (polyurethane foam or cellular rubber) with 10mm in thickness. In sum, four double-layered composite structures with different layouts of adsorbents in each structure were studied.
Results: The location of natural fiber can play a critical role in the acoustic performance of the double-layered composite structures such that comparing the studied double-layered composites revealed that when the natural fiber was the first layer exposed to the normal sound in the double-layered composites with 20mm in thickness, the trend of acoustic performance was approximately the same as the single-layered composite of natural fiber with 20mm in thickness; but in the composite structures, when the synthetic adsorbent was the first layer exposed to the sound, the trend of acoustic absorption was improved.
Conclusion: On the basis of the results, the double-layered composite structure with a higher-density and lower-porosity upper layer showed a better acoustic absorption trend than the single-layered composite including the natural adsorbent.
Mohammad Hosein Beheshti, Roohalah Hajizadeh, Ali Alami, Mojtaba Emkani, Yasin Mansouri, Ali Tajpoor,
Volume 11, Issue 3 (9-2021)
Abstract
Introduction: Accidents caused by children’s play equipment are considered a serious threat to children’s health. The aim of this study was to design slide, swing and see-saw based on national standards and children’s anthropometric data.
Material and Methods: The present study is an applied research, in which the design of children’s play equipment, including slides, swing and see-saw was done according to national standards No. 6436-2, 6436-3 and 6436-6, as well as measuring the anthropometric dimensions. All anthropometric data of 385 children aged 2 to 12 years were measured and equipment design was performed using Minitab software.
Results: In the national standards No. 6436-2, 6436-3 and 6436-6, the size of more dimensions required for the design of the slides, swing, and see-saw is not stated. In the present study, the ergonomic and standard design of these types of equipment is shown. Comparison of designed see-saw with see-saw available in parks showed that the length and width of the see-saw should be 0.37 and 0.25 meters, respectively. In the current study, however, they were 0.24 and 0.35 meters, respectively. Also, the height, width and depth of the swing chair should be 0.2, 0.35 and 0.37 meters, while their actual size in the studied parks was 0.25, 0.42 and 0.31 meters, respectively.
Conclusion: The result of this study is helpful for standard and ergonomic designing of children’s play equipment and is very useful for urban planning. This study emphasizes the revision of national standards.
Davood Mahmoudi, Jalil Nazari, Leila Rastgoo, Mohammad Asghari Jafarabadi,
Volume 11, Issue 3 (9-2021)
Abstract
Introduction: The carpet industry is one of the most important handicrafts in Iran. This industry is one of the most difficult and harmful professions, in which the employees are often working in a workplace with non-ergonomic, unsafe, and unhealthy conditions. The present study aimed to address the modeling of the individual, job characteristics, and workplace conditions with the general health of carpet weavers through an ergonomic approach.
Material and Methods: The current study was a descriptive-analytic survey. The study population was female workers, who have had a minimum of one-year work experience and working in the workshops located in Meshginshahr city villages. The data collection tool was a combination questionnaire including, Goldberg’s questionnaire (GHQ-28), NIOSH questionnaire (disease history section), and questions about workplace conditions. The obtained data were entered into SPSS-17 software and analyzed statistically using statistical modeling based on the general linear model, multivariate and other statistical tests.
Results: Unpleasant condition was observed among the 37.4% of the examined, in terms of general health. Logistic regression modeling was used to investigate the internal and external factors of carpet weavers with their general health status. According to the model, general health has a significant relationship (p<0.05) with most of the internal factors such as age, marital status, history of disease, etc. However, there was no significant relationship with the workplace conditions.
Conclusion: According to the results of this study, it can be concluded that demographic and job variables are of the most important factors affecting the general health of carpet weavers. Although in the model, the workplace conditions did not show any significant relationship with the components of general health, interpreting these findings requires more studies. More studies are required objectively to identify the effect causes of the general health of carpet weavers (especially workplace conditions).
Sajad Bahrami, Ahad Sotoudeh, Naser Jamshidi, Mohammad Reza Elmi, Mohammad Saeid Poorsoleiman,
Volume 11, Issue 4 (12-2021)
Abstract
Introduction: Chemical industries often have risks for the environment and communities, due to the use of complex facilities and processes. Also, in the ammonia tanks, the probability of risk of explosion is high, owing to their specific characteristics. The aim of this study is to evaluate the risks of explosion scenario at the ammonia tank in the Kermanshah petrochemical complex
Material and Methods: To achieve the purpose of this study, the Fuzzy Fault Tree Analysis (FTA) method was used to estimate the probability of reliability in the basic events. In this study, after drawing Fault Tree for identifying basic events, the probability of basic events was estimated by means of expert’s elicitation, and the probability of minimal cut sets was computed through Boolean logic gates.
Results: According to the results, the probability of occurrence of the top event was obtained equal to 0/054997. In the minimal cut set prioritizing, the failing of pressure safety valves identified as the most effective factor in the top event occurrence, and afterward failing the control valves and human errors were identified.
Conclusion: This study indicates that, based on expert elicitation, a fuzzy error tree method can be used to assess the risk of various scenarios in the industry. Overall, in assessing the risk of the explosion scenario in the ammonia reservoir, it was found that some minor defects, and even human error, could be considered as a major contributor to the explosion.
Mohammad Yadegaripour, Malihe Hadadnezhad, Ali Abbasi, Fereshteh Eftekhari,
Volume 11, Issue 4 (12-2021)
Abstract
Introduction: Low back pain is one of the most common musculoskeletal disorders leading to disability around the world. Several studies have suggested that prolonged computer/ laptop work contributes to the development of low back pain and discomfort. The results of the studies conducted on the association of back discomfort and muscle activity are contradictory. Thus, the present study aims to evaluate the relationship between the activity level and relative rest time of the trunk muscles with back discomfort while working with a laptop in a sitting position.
Material and Methods: First, 20 young healthy males performed laptop work including mouse work and typing in conventional and ergonomic setups. In the ergonomic setup, the screen height and keyboard placement were specifically adjusted for each individual. In addition, the electromyographic activity of the lumbar erector spinae, right and left multifidus and transversus abdominis, rectus abdominis, external oblique muscles, and the posture of the lumbar spine were recorded in the first and last two minutes of an 8-min task. After the end of each task, the participants scored their back discomfort.
Results: The results showed a positive correlation (r=0.57 and p=0.009) between back discomfort and the EMG amplitude of the lumbar erector spinae muscle. In addition, back discomfort was negatively correlated to the relative rest time of the multifidus muscle (r=0.50 and p=0.023), and a positive correlation was reported with the relative rest time of the transversus and rectus abdominis (r=0.47, p=0.039, and r=0.45, p=0.049, respectively).
Conclusion: The relative rest time of the trunk muscles may be a better index than that of the EMG amplitude to highlight the risk factors for back discomfort. However, a causative link between muscle activity and discomfort cannot be implied from this study. The current results do not undermine the role of other factors associated with the increased level of discomfort during sitting.
Milad Abbasi, Mohammad Reza Monazzam, Mansour Shamsipour, Hossein Arabalibeik,
Volume 11, Issue 4 (12-2021)
Abstract
Introduction: There are several generic and specific models to assess the individual job performance (IJP). While these methods may provide the valuable information, none of them cover the complexity and wide range of the behaviors which express the IJP. This review study aimed to identify all existing models and incorporate them to achieve a comprehensive conceptual model to assess the IJP.
Material and Methods: Databases such as PubMed, Scopus, Embase, and ProQuest were systematically searched to meet the study’s goals. Moreover, references to relevant publications were examined. Finally, suitable publications were discovered and analyzed using the inclusion and exclusion criteria.
Results: The results of Search in databases, including PubMed, Scopus, Embase, and ProQuest, showed that 12754 articles were found in the initial search. After removing duplicate and unrelated articles, finally, 155 eligible articles were selected. Based on full-text screening, 10 studies were excluded, and 5 studies were not accessible. Finally, by checking the references mentioned in the selected articles, 4 more eligible articles which were not retrieved in the search strategy were added; finally, 61 articles were selected to be reviewed. Ninteen articles were related to the general models, and 19 articles addressed job-specific assessment models. The remaining 23 articles described other existing models.
Conclusion: To evaluate IJP, a heuristic structure was developed based on the literature research. These dimensions were selected because they can accommodate all of the preceding models’ dimensions. They also include any behaviors that may have an impact on IJP.
Taleb Askaripoor, Majid Motamedzade, Rostam Golmohammadi, Mohammad Babamiri, Maryam Farhadian, Hamed Aghaei, Mohammad Ebrahim Ghaffari, Elahe Kazemi, Mehdi Samavati,
Volume 11, Issue 4 (12-2021)
Abstract
Introduction: Recent evidence indicates that lighting can affect physiological and neurobehavioral human functions, referred to as non-image forming (NIF) effects of lighteffects. This study aimed to determine the effects of illumination levels and correlated color temperature (CCT) on alertness and performance under NIF conditions.
Material and Methods: In this study, 22 participants were exposed to light at various levels of illumination, including very low illuminance (<5 lux, control) and light conditions with correlated color temperatures (CCT) of 4000 K, 8000 K, and 12000 K at 300 and 500 lux. The data collection process included recording the power of brainwaves (alpha, alpha-theta, beta, and theta), sleepiness and mood scales, and cognitive performance tests for sustained attention, psychomotor vigilance task (PVT), working memory, and inhibitory capacity.
Results: The results indicated that 500 lux light conditions at correlated color temperatures of 8000 and 12000K significantly reduced normalized alpha, alpha-theta power, subjective sleepiness, and performance compared to the dim light condition. Under illumination levels of 300 and 500 lux, there were no significant differences in the measured values of the variables.
Conclusion: Lighting interventions can be used as a supplement to other strategies for increasing alertness and performance in the workplace.
