Iranian Journal of Ergonomics

The Mediating Role of Job Control in the Explaining the Relationship Between Job Satisfaction and Mental Workload in Nurses

Maryam Feiz Arefi

Background and Aim: Nurses are the main staff of the hospital. The large number of clients, the high volume of work and the shortage of staff increase the mental workload of nurses. On the other hand, reducing the control of the work process leads to mental stress. The purpose of this study was to investigate the mediating role of job control and explaining the relationship between job satisfaction and mental workload in nurses.
Methods: This descriptive-analytical study was performed on 188 nurses of educational hospitals in Shushtar and Ardabil cities, Iran, in 2019. Research tools included demographic information questionnaire, NASA-TLX questionnaire, Job description index (JDI) questionnaire, and job control questionnaire. For Data analysis the correlation coefficient and regression analysis with SPSS-18 and AMOS-18 software were used.
Results: Based on the results, the final model had good fitness (GFI=0.859, CFI=0.921, RMSEA=0.067). The results also showed that there is a significant relationship between mental workload and job satisfaction (P<0.001, r=-0.33) and this relationship has increased with the presence of job control (P<0.001, r=-0.42).
Conclusion: High levels of job control are associated with increased job satisfaction and reduced workload. As a result, in order to reduce the mental workload and increase job satisfaction, job control of nurses can be increased to improve working conditions.

An Ergonomic Approach to Designing an Iranian-Islamic Toilet in a Sample of Iranian Society

Seyedeh Fatemeh Razzaghi Pahnehkolai

Background and Aim: Two toilets in sitting-type and squatting-type (Traditional) are currently used by Iranian People. Since each of these two types has its own disadvantages and merits, this research aims to design a squatting-type toilet based on ergonomic principles to eliminate its disadvantages.
Methods: 61 subjects (29 males and 32 females) aged 19-60 years were enrolled in this study. Seven anthropometric characteristics were measured using a tape measure with an accuracy of one millimeter in these subjects. A questionnaire containing 4 questions was given to them. Each person was squatting for 2 minutes on different slopes from 0 to 20 degrees. Assessment of Localized Postural Discomfort (LPD) by asking people at 3 points of body, at different slopes, and goniometry in the areas of (A), (B) ,(C) and (D) was also performed.
Results: Based on the anthropometric characteristics of the individuals, LPD and goniometry findings in different areas of the body and dimensions of toilet in the sole position, length 32.33 and width 12.74 cm was obtained. The angle between the soles of the feet was 23.33 degrees and the required slope of the soles was 12 degrees.
Conclusion: The findings of this study suggest that modification of the sole position in squatting-type toilet and its sloping design can be effective in making users comfortable. Given the small number of studies on this type of toilet, further studies in this area, including research on specific populations such as the disabled people, children, pregnant women, the elderly, etc., are necessary.

The Effect of Job Nature on Job Adjustment of Nurses in Hospital Affiliated to Kashan University of Medical Sciences

Hamid Rahimi

Background and Aim: Job adjustment is an important factor for the successful employment of nurses. The job nature can be a factor influencing job adjustment. The aim of the present study was to investigate the effect of job nature on job adjustment among a sample of nurses.
Methods: This cross-sectional study was conducted among 542 nurses working in hospitals affiliated to Kashan University of Medical Sciences. Using Cochran's formula and stratified random sampling method, 190 nurses were selected as a sample. Two standard and validated questionnaires were used for gathering data associated with job nature and job adjustment. The reliability of the questionnaires was estimated through Cronbach's alpha coefficient. Data analysis was performed at both descriptive and inferential levels using SPSS 22.
Results: Findings revealed that means of job nature (70.43±45.07) was higher than average (60) and mean of job adjustment (3.23±0.42) was higher than average (3). Pearson correlation coefficient showed that there is a positive and significant relationship between job nature and job adjustment (r=0.29). The regression coefficient showed that the job nature was able to predict the job adjustment of nurses.
Conclusion: The average job nature and adjustment of nurses were favorable and there was a positive relationship between job nature and job adjustment of nurses. Therefore, in order to increase the adjustment of nurses, managers should pay more attention to nurses' perceptions of their job characteristics and provide them with diversity, feedback and the opportunity to create friendly relationships at work.

Ergonomic Assessment and Design of the Tower Crane Cabin Based on Anthropometric Dimensions of Iranian Operators

Taleb Askaripoor

Background and Aim: Despite the main role of cranes in advancing construction operations, however, accidents and occupational injuries resulting from their activities have become a critical issue. Recent evidence suggests that the cause of these problems may be associated with the absence of design of the interior space of the crane cabin, and the tasks of the operators, based on ergonomic principles. This study was conducted to assess the ergonomic risk of the tower crane operator’s activities and redesigning the dimensions and interior space of these cranes, based on the anthropometric dimensions of Iranian operators.
Methods: In this descriptive cross-sectional study, 30 male tower crane operators working on three major construction projects in Tehran were investigated. Initially, a multi-step approach was applied to define the problem, including: observing the working statuses, interviewing operators, Nordic Musculoskeletal Disorder Questionnaire, and rapid upper limb assessment (RULA) method. Then, using anthropometric data, the dimensions and interior space of the crane chamber were redesigned.
Results: The results of the rapid upper limb assessment method showed that the activities of tower crane operators were at high and very high-risk levels. Also, 85% and 38.5% of these people reported pain and discomfort in one of the nine areas of their body in the last 12 months and 7 days, respectively. In this study, the dimensions of the interior space of the redesigned tower crane cabin were obtained 160.8×144.1×199.7.
Conclusion: Based on the results of the study, it can be concluded that the current interior design of the tower crane cabin does not fulfill the needs of the operators. Hence, redesigning it appears essential to enhance human-machine compatibility, improve safety and productivity, and prevent musculoskeletal disorders (MSD).

The Application of Lean Production in Reducing Human Error and Improving Response in Emergencies: A case Study in a Petrochemical Industry

Iraj Mohammadfam

Background and Aim: Petrochemical industry is one of the most accident-prone industries, and most accidents in this industry are related to human factors. The principles of Lean production are one of the approaches used to improve the production situation. Various studies have shown that implementing Lean production improves the safety and ergonomics. In this study, the principles of Lean production were used to reduce human error and improve response in emergencies.
Methods: The basic CREAM method was used to evaluate human errors. In order to select Lean production tools appropriate to the emergency response tasks, the opinions of the 20-member panel of specialists and experts, including industry managers, HSE officials, and university professors, were used. For examining the impact of Lean production principles on reducing human error in emergencies, 6 months after the implementation of Lean production interventions, human error was re-examined. Evaluation of human errors after Lean production interventions was also performed by basic CREAM method.
Results: The results of the evaluation of human errors before and after the implementation of Lean production interventions showed that the level of control mode of the three sub-tasks improved from the tactical control mode to the strategic control mode. The most probable human error was in evacuate sub-task.
Conclusion: The results of this study showed that the implementation of those interventions that in addition to improving the level of safety, can improve organizational productivity, is more accepted by industry management.

Design and Validation of Non-Exercise Equations for Estimation of Aerobic Capacity in Iranian Boys

farzad nazem

Background and Aim: Accurate and rapid measurement of cardiorespiratory system performance by estimation methods regardless of basic physiological fitness level, geographical environment, culture and nutrition is of paramount importance. The purpose of this study was to design linear regression equations to estimate the aerobic capacity of healthy adolescent boys without the use of sport tests and validation of this equations.
Methods: In the present semi-experimental study, 156 healthy adolescent boys aged 13 to 17 years with a mean body mass index of 21.43 ± 4.5 Kg / m² were selected by purposive sampling method. To design the non-sport equation for estimating maximum oxygen consumption (VO_2peak), a multiple regression linear model and Pearson correlation were used to validate the equations.
Results: Significant correlations were observed between the measured VO_2peak and the anthropometric and physiological variables (R=0.122 - 0.799, P<0.001). Also, a valid non-exercise linear equation for boys' VO_2peak prediction was designed with variables such as age, BMI and resting heart rate (SEE = 3.59 mL/kg/min, R² = 0.712, P<0.001). The estimated VO_2peak from equations had a significant correlation with the obtained criterion value. (R = 0.707 – 0.730, P<0.01).
Conclusion: According to the results of the present study, it is possible to use aerobic capacity estimation equations, is a simple, accurate, safe tool in assessing the baseline cardiorespiratory fitness (VO_2peak). The use of non-Exercise equations in the planning of exercise in large populations of adolescent boys and even as a daily clinical practice in the elderly and heart patients with the goals of promoting health, cardiovascular health, preventive actions is very important.

Application of Digimizer Image Analysis Software In Facial Anthropometry

Alireza Choobineh

Introduction: Craniofacial anthropometry and anthropometric ratios are used in different sciences such as dentistry, medicine, oral and maxillofacial surgery, growth studies, plastic surgery, bioengineering and production of personal protective equipment. The purpose of this study is to introduce Digimizer software to measure facial dimensions and compare manual dimensional measurement and photoanthropometry with this software.
Methods: In This descriptive-analytical study 12 female students of Shiraz University of Medical Sciences participated. Measurement of face dimensions of samples was done manually and by photographic methods and data analysis was performed with SPSS software version 19 and descriptive-analytical tests.
Results: From the ten dimensions of the measured dimensions, a significant difference was observed in the three dimensions of the Subnasal-Nasal Root Length (SNRL), Menton-Nasal Root Length (MNRL) (Face Length) and Bitragion-Menton Arc (TRMA) dimensions,(P <0.05 ). No significant differences were observed in other dimensions. The ICC (Intra Class Correlation) coefficient for both methods was obtained in the range of 0.56-0.94.
Conclusion: This study showed that the use of Digimizer software can replace the use of manual method in measuring the dimensions of the face and in the preparation of anthropometric database of the face in less time is preferable to the manual method.

The Effect of Organizational Architecture on Performance Management with the Mediating role of Organizational Agility of Physical Education Departments of Medical Sciences Universities in the Country

Mojdeh Shakari

Background and aim: Nowadays performance management is used to make organizational agility and improve organizational architecture. The purpose of this study was to determine the effect of organizational architecture on performance management with the mediating role of organizational agility of physical education departments of country's medical science universities.
Methods: The method is a descriptive-survey research and operational and applied in terms of purpose. The statistics of this study included all senior managers and staff of physical education departments in medical universities throughout Iran, selected as a statistical sample for a total of 216. Data collection tools were organizational architecture questionnaire, Baldrige performance standard questionnaire and Sharifi organizational agility questionnaire. In order to analyze the research findings, path analysis and structural equations and SPSS 20 were used.
Results: It showed that organizational architecture and its dimensions have a significant effect on performance management with the mediating role of organizational agility of physical education departments in medical universities of the country. The magnitude of the effect of the mediating variable using VAF was 0.228 and according to the magnitude of the direct effect of the independent variable on the dependent which was equal to 0.799, it can be said that the magnitude of the direct effect is greater than the indirect effect.
Conclusion: In modern performance management, the aims of staffs and the purposes of the organization should be aligned and by creating coordination and providing the necessary guidance by supervisors, people feel more belonging to the organization and make the organization more agile by organizational changes.