Today, spot welding plays a special role in many engineering industries. Important industries such as automobiles use this method to connect different parts of sheets in the car body. The most ...important part of spot welding is to ensure that the weld is healthy, and it is very important and the best way to inspect using non-destructive tests. Ultrasonic testing (UT) has a high ability to detect defects in spot welding. The present article intends to review the ultrasonic testing techniques used in spot welding. The importance of fault detection and interpretation of defect signals in the ultrasonic test and the time of obtaining the defect for this weld have been reviewed. In the present paper, most of the proposed stainless steel and aluminum sheets have been inspected by spot welding and accurate results are available. The best mechanism and method for measuring their defects according to time calculations is proposed. It is easier to detect access defect echo and way of detecting it in the experimental test. For all sheets, cracking, porosity and single pore defects have been investigated and reported. The simulation process for all defects is also classified and brought according to the defect echo time calculations to ensure the experimental method. The choice of ultrasonic testing methods in the detection of defects is a new and good method. The spot welding process depends on non-destructive testing and the capabilities and techniques of ultrasound.
Today, automotive fires can have various causes, such as technical defects, engine overheating, fuel system leaks, and so on. If these notifications are detected by a sensor or actuator, human and ...financial loses will be prevented. Introduction and installation of these sensors and actuators requires proper review and design, which in this article was considered the best design for them. An automatic and intelligent and extinguishing system will prevent the human and financial losses due to catching fire of automotive. The sensors play a major role in this design, forcing the driver to leave the automotive by announcing a fire hazard. The new design was done on the automotives odometer by sending an command from the sensor and will prevent the fire by displaying a warning sign. This sign on the automotives odometer is used by sensors to alert the driver and passengers to leave the automotive. In this article, another new design is opening relay of doors’ lock. This relay takes its command from the microcontroller, and it is connected to the central locking circuit of the automotive doors. As soon as it receives voltage from the microcontroller, it enters the central locking circuit and opens the locks. Another suggestion is installation of a communication system by a drivers’ mobile phone by defining the SIM card module for the driver and informing him catching the fire. The spray pipes and nozzles were connected to extinguish the fire, and in order to prevent the automotive from catching fire, it used water spray. Diagrams were drawn to compare the new design, which outweighs the advantages of this new design related to its use in automotives. According to the diagrams, human safety against fire was reported to be 99%.
In the face of COVID-19, healthcare workers need to cope with the ongoing stressors at play and keep psychological distress at a minimum level. This study examined the psychosocial and demographic ...factors associated with nurse's resilience in the hospitals of Ahvaz that is one of the top cities infected with COVID-19 in Iran.
The present cross-sectional study was conducted on 387 Iranian nurses in Ahvaz city. For data collection purposes, three online questionnaires (including Copenhagen Psychosocial, Demographic, and Connor-Davidson Resilience Scale) were distributed among the participants.
The mean resilience score was equal to 61.8 ± 14.8 for 387 nurses. Resilience had a statistically significant negative correlation with quantitative demand (
= -0.273,
< 0.008), work pace (
= -0.262,
< 0.011), emotional demand (
= -0.226,
< 0.030), stress (
= -0.458,
< 0.000), and burnout (
= -0.287,
< 0.005). Multiple linear regression analysis indicated that stress, job satisfaction, burnout and age were the main predictors of nurses' resilience during the (COVID-19) pandemic (
= 0.45).
We identified psychosocial and demographic predictive factors that may contribute to greater resilience among nurses during the COVID-19 outbreak. The findings of this study can be used to implement psychosocial interventions to amplify the resilience of medical staff during the COVID-19 outbreak.
This study aimed to determine the effect of the physical workload on the back, neck and shoulders of welders. The prevalence of musculoskeletal symptoms was assessed using the Nordic questionnaire ...among 15 welders. The physical workload of the neck, back and upper arms was then measured by means of inclinometry as the welders were working. The results revealed that the highest prevalence of musculoskeletal disorders during the previous 12 months was in the lower back and shoulders. The median trunk and neck flexion were significantly associated with back and neck pain in welders with symptoms during the past year (p < 0.05). Physical exposure in welders with pain was characterized by significantly more awkward postures and percentage of time spent with the trunk and neck flexed more than 20°. The nature of their work and the design of their workstations may be causes of the symptoms they experienced during work.
Today, Phased Array Ultrasonic Testing (PAUT) is a suitable method for detecting defects in Non-destructive Testing (NDT). This simulation was done with a new method on a stainless steel pipe with a ...diameter of 500 mm and a length of 1,000 mm, and cracks were modeled on the external and internal surfaces and corrosion defects on the internal surface. Four probes with a characteristic of 2 MHz were used simultaneously, each probe having 64 elements. By increasing the number of probes and their elements, more accurate information about the defects is obtained, which makes it easier to detect the location and leads to a reduction of scattered signals and noise, which can detect even small size defects. Considering this important advantage, a new use of the method of increasing the number of probes in PAUT is reported in this study to detect defects, especially corrosion defects. The results of geometric anisotropy studies of group velocity and phase of horizontally polarized shear waves (SH-waves) for stainless steel pipe were presented. Due to the isotropic properties of the pipe material, the speed on the outer surface of the pipe in the direction of the cover is 40 m/s higher than the generatrix.
In 2011, load limits for manual lifting were adopted in Iran to protect workers from low back injury without prior testing of accuracy with Iranian workers. This investigation examined how accurate ...the adopted ACGIH TLVs at the allowable limits predict risk for LBP disorders for a group of Iranian workers using biomechanical criteria. Testing took place in the laboratory with participants completing a series of 2-handed lifting tasks as defined in the Iranian Guideline for Manual Lifting. To test accuracy, both compression and shear forces were estimated for fifteen male Iranian workers who completed 25 lift combinations that varied in height and reach with the maximal allowable load. The findings, when compared to a risk threshold of 3400 N compression and 700 N shear, showed above-threshold forces for compression and little-to-no safety margins with repetitive lifting for most lifts at torso height and below. Since Government, employers and workers use these guidelines to decide on work/workplace design; these guidelines require further review and revision based on the anthropometrics of Iranian people.
Introduction: Musculoskeletal disorders (MSDs) have a multifactorial nature. Biomechanical factors are one of the most important factors. Consequently, the precise identification of effective factors ...plays a significant role in controlling and preventing these disorders. Therefore, the current study aimed to identify the awkward upper body postures and their effect on the prevalence of MSDs in office workers in both women and men groups by objective methods. Material and Methods: In this cross-sectional study, the participants were 36 office workers (18 women and 18 men). The prevalence of musculoskeletal discomfort was evaluated using the Nordic questionnaire. The upper limbs posture, including the back, neck, and wrists, was evaluated continuously with an electronic inclinometer and an electrogoniometer for 30 min, followed by analyzing the collected data. Results: The results revealed that the highest prevalence of musculoskeletal symptoms in both gender groups was in the neck (58.33%), trunk (52.77%), and wrist (47.22%), respectively. The results disclosed that the median trunk and neck flexion in both groups is over 20° and the posture angle in women is higher than that of men (P<0.05). The results showed that pain and discomfort in the trunk and neck in both gender groups have a significant relationship with the median posture angle (P<0.05). Also, the wrist posture in both gender groups during work was in extension and static condition. Conclusion: Based on the results of this study, the prevalence of disorders in women was higher than in men. Although the tasks performed in both groups were similar, the assessment of postures disclosed that women office workers had more awkward postures in the trunk and neck than men. In both groups, the prevalence of musculoskeletal discomfort had a significant relationship with awkward postures in the trunk and neck. According to the results of the current study, ergonomic interventions are recommended to reduce awkward postures and to prevent MSDs, particularly among women office workers.
Background and Objective: Work-related musculoskeletal disorders are among the most common types of occupational diseases. This study aimed to investigate the relationship between lifestyle and ...mental workload components with the prevalence of musculoskeletal disorders in employees working in the automotive industry. Materials and Methods: This cross-sectional study was conducted on 303 employees working in a car manufacturing complex in Iran. The required data related to demographic characteristics, the prevalence of musculoskeletal discomfort, lifestyle, and mental workload were collected using demographic, Cornell, Walker health-promoting lifestyle, and NASA-TLX questionnaires, respectively. Results: According to the results, 70.70% of the participants experienced musculoskeletal disorders in at least one of their organs. Moreover, musculoskeletal disorders were significantly correlated with age and work experience (individual characteristics); responsibility, health concerns, and exercise (lifestyle); as well as physical workload and time pressure (mental workload) (P<0.05). Conclusion: The present study results revealed a high prevalence rate of musculoskeletal disorders in the automotive industry; moreover, lifestyle and mental workload parameters are among the most critical risk factors in the prevalence of musculoskeletal disorders. Accordingly, it is necessary to take measures by monitoring individual, physical, and cognitive risk factors to reduce the prevalence of these disorders.
Introduction: Occupational back pain is one of the musculoskeletal disorders (MSDs) caused by manual load-lifting among women involved in manual lifting activities. Limits for lifting loads are used ...to assess the risk and prevention of occupational back pain. The Washington Industrial Safety and Health Act (WISHA) checklist is used as a permissible load assessment limit in Iran. The present study aimed to evaluate the reliability of using the WISHA checklist to determine the allowable limits of manual load-lifting among women based on biomechanical and psychophysical methods. Material and Methods: In this study, ten women workers aged 20-30 years with a history of manual load-lifting were asked to perform 21 load-lifting tasks designed according to the permitted limits of Iran. A wireless electronic clinometer was used to determine the flexion angles of the trunk while lifting the load. Anthropometric information, load weight, trunk angle, and posture were entered into 3DSSPP software to obtain biomechanical forces for each task and compared them with the recommended National Institute for Occupational Safety and Health (NIOSH) limits. After performing each task, the rate of perceived exertion of each person for each task was collected by using the Borg scale. Results: The flexion angle for 47.61% of the lifting tasks were more than 20 degrees. The estimated average compressive force for the six tasks exceeded NIOSH’s recommended limits. The average Borg scale was determined hard for 33.33% of lifting tasks and hard to very hard for 9.52% of tasks. Conclusion: It was found that the manual load-lifting standard for some tasks might not be sufficient to control and prevent low back pain caused by manual lifting in women, and some non-compliance was found with the allowable lifting limits. Manual load-lifting with anthropometric and biomechanical features may increase the biomechanical force on the women’s low back. Therefore, it seems that the allowable lifting limits of Iran for women based on the WISHA checklist should be reviewed and redesigned based on anthropometric and biomechanical characteristics.
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