Iranian Journal of Ergonomics

Comprehensive ergonomic interventions for improving ergonomic conditions in an automobile spare part manufacturing plant: A case study

Naser Sadra Abarghouei

Introduction: Musculoskeletal disorders are major concerns of the modern world due to their effect on the physical health and productivity of the workforce. More extensive research is therefore required to identify and prevent these injuries and control the risk factors causing their development.

Materials and Methods: The present study uses a theoretical model of ergonomic interventions to examine and improve ergonomic conditions in an automobile spare part manufacturing plant. A total of 44 employees were selected through simple random sampling and according to the Morgan table from the 50 personnel working at the plant. The Nordic Musculoskeletal questionnaire and the review of ergonomics tips inventory were used to identify the ergonomic risk factors. Based on the theoretical model used in the research, the ergonomic intervention was performed in two stages.

Findings: In the macro stage of the ergonomic intervention, 7 goals were set and 13 ergonomic recommendations were made in the form of several workshops and task forces. In the micro stage of the ergonomic intervention, 20 ergonomic risk factors were identified and 13 strategies and plans were suggested. With the senior manager's approval, 11 strategies entered the implementation stage with the aim of improving ergonomic conditions and increasing productivity at the workplace.

Conclusion: The main outcome of the comprehensive ergonomic interventions performed in the present study was a modified organizational culture, entailing both direct and indirect benefits, such as providing low-cost or no-cost solutions to the problems, creating an active environment of continuous improvement, increasing employees' motivation for participation and being innovative in solving the problems, increasing the inclination among the employees to be an innovative thinker, improving communication between the authorities and the personnel and increasing the employees' general knowledge and capabilities.

The relationship between sound annoyance and general health in hospital personnel in Shiraz in 2014-15

Parisa Azad

Introduction: As a healthcare providing establishment, hospitals can be affected by sources of noise pollution which then impose negative effects on the health and comfort of patients and personnel. The present study was conducted to determine the relationship between sound annoyance and general health in the personnel of university affiliated and non-university affiliated hospitals in Shiraz.

Materials and Methods: The present descriptive analytical study was conducted in four university affiliated and non-university affiliated hospitals in Shiraz with a sample size of 300 using a predetermined equation and according to the results of previous studies. The instruments used in the study included the General Health Questionnaire (GHQ), the Noise Annoyance Scale (NAS) and an audiometer (CEL-440 model).

Findings: The present study found a small inverse relationship between the total general health score in the hospital personnel and the sound pressure level at university-affiliated hospitals (r=-0.103) and a direct positive relationship at non-university affiliated hospitals (r=0.274), which were not statistically significant (P≤0.05). The relationship of somatic symptoms, anxiety, insomnia, social dysfunction and depression to sound pressure was inverse and small (r=-0.195 and P≥0.05). However, there was a direct positive relationship between general health and sound annoyance (r=0.266 and P≤0.05).Conclusion: According to the results obtained, noise levels are higher than the acceptable exposure limit in university-affiliated hospitals, which affect both the patients' and the personnel's general health, necessitating the adoption of control measures.

Aerobic fitness and its relationship to memory function and academic achievement: A review of evidence

Malihe Saeedy

Introduction: Academic achievement is one of the main objectives of educational programs and the most important concern of education administrators and families. The education administrators' emphasis on courses other than physical education as a means for the students to get better overall scores results in a general neglect toward physical education or its elimination from curricula due to reasons such as shortage of funds. Physical activity is claimed to affect the structure of the brain and improve memory function and ultimately lead to academic achievement. The purpose of the present review study is to examine the current evidence on the relationship between aerobic fitness and academic achievement.

Materials and Methods: Different articles and papers were accessed through databases and search engines such as ‎Google Scholar‎, PubMed and Elsevier and using keywords such as “academic achievement”, “aerobic fitness” and “memory”. The articles used were published between 1998 and 2014.

Findings: The hippocampus function is an important factor in the consolidation of short-term and long-term memory and is severely affected by neurotransmitters and hormones. Physical activities at an intensity higher than average have a strong effect on the release and regulation of hormones and neurotransmitters and thus improve the memory function indirectly. Studies have shown that physical activity has a positive effect on scores obtained in different courses, particularly in mathematics, through increasing the aerobic capacity.

Conclusion: The aerobic fitness following regular physical activity not only leads to general health and reduces the risk factors of health and the incidence of diseases, but also improves the memory function and ultimately leads to academic achievement through affecting the brain structure physical education courses should therefore be more emphasized at schools.

The relationship between the prevalence of musculoskeletal disorders in carpet weavers and the lighting in carpet weaving workshops in Takab in 2013

Leila Gheibi

Introduction: Unsuitable and nonstandard tools, insufficient lighting and the lack of adequate rest in carpet weavers leads to an increased prevalence of musculoskeletal disorders in this group of workers that needs to be reduced through the better supervision of carpet weaving workshops.

Materials and Methods: The present descriptive cross-sectional analysis was conducted in rural carpet weaving workshops of Takab, Iran. A total of 86 carpet weaving workshops were selected through cluster sampling, which employed 222 carpet weavers overall. The general and local lighting was measured in the workshops by a photometer (LX-13 model) and the workers' musculoskeletal disorders were assessed using the Nordic Musculoskeletal Questionnaire.

Findings: The results of the study reveal back disorders to have been the most (61.3%) and elbow disorder the least (7.2%) frequent among carpet weavers. The majority of the workshops had a general lighting (82.4% of the workshops) and local lighting (91.9% of the workshops) below the recommended limits.

Conclusion: The extended involvement of the upper limbs in carpet-weaving increases the prevalence of disorders in these organs. The results indicate that the majority of carpet weavers worked in workshops with non-standard lighting. The variables that were most effective in the development of neck and back disorders were the workers' years of work experience and the general lighting at their workplace while the variable that was most effective in the development of wrist and shoulder disorders was the workers' years of work experience only.

Content and trend analysis of articles published in a key journal on human factors and ergonomics during 2005-2014

Yahya Khosravi

Introduction: The introduction of a thematic framework is necessary for the field of ergonomics and human factors. Content analysis is a useful tool for the trend analysis and distribution of published articles however, reports on the content analysis of ergonomics journals are rare. The present study was conducted to identify research trends in the journal of Human Factors through a content analysis of its recent articles published over the past ten years (2005-2014).

Materials and Methods: The present study used the directed content analysis method. Two analysis experts classified 741 articles based on their thematic codes. A conceptual framework was used to perform the content analysis. EXCEL 2007 and SPSS-19 were used for the data preparation, theme distribution and trend analysis of the published themes.

Results: From the total of 21 themes extracted, six themes defined over 50% of the variance in the published articles, including “Biomechanics, Anthropometry and Work Physiology", "Display and Control Design", "Surface Transportation Systems", "Cognitive Processes", "Attentional Processes" and "Sensory, Perceptual and Psychomotor Processes". The journal had a special focus on "Biomechanics, Anthropometry and Work Physiology" (about 12%).

Conclusion: The thematic framework and distribution pattern noticed in this study can be used for planning education and research on human factors and ergonomics in universities, research centers and related organizations.

The quality of Kansei engineering design: A case study of a branch of Bank Maskan in Sari

Mahsa Bagheri

Introduction: Creating an appropriate and efficient workplace environment is a fundamental part of businesses in the modern world. The proper design of interior spaces and exterior facades in workplaces invigorates the workforce and reduces the risk of depression for them, while also improving the quality of their work and the attraction of customers.

Nevertheless, architects tend to design workplace environments solely based on personal taste and emotional preferences. The present study designed a branch of Bank Maskan in Sari, Iran, by using efficient scientific methods and with a focus on the quantitative and qualitative aspects of design.

Materials and Methods: The present study was conducted to design a workplace environment using the Kansei engineering method. It used the facade openings of a branch of Maskan Bank in Sari as its case study and extracted the users' preferences using the Kansei method in order to find physical patterns for designing facade openings based on scientific analysis of the data obtained. The researcher examined the dominant emotional preferences using the Kansei engineering method and had 200 individuals selected from the sample population fill out a questionnaire that was scored using Semantic Differential (SD) and based on a 7-point Likert scale. The data obtained were analyzed in SPSS-16 using a test for mean and the Pearson correlation test.

Findings: The findings of the present study confirmed the significant relationship between the quantitative (the type of openings) and qualitative (Kansei terms) characteristics of design using the Kansei engineering method and also showed that arched openings, with attributes of religiosity such as “loyal”, “trustworthy” and “moderate” (with correlation values of 0.6, 0.6 and 0.63, in respective order), and rectangular openings with vertical elongation, with attributes of economics and banking such as “stability” (with the correlation value of 0.62), have obtained the highest degree of correlation.

Conclusion: Given the positive effects of physical patterns, and as traditional arched openings imply attributes such as religiosity while rectangular openings with vertical elongation imply positive economics and banking attributes, these openings were deemed suitable for designing the facade of the examined branch of Maskan Bank in Sari.

The effect of non-powered hand tools' diameter on comfort and maximum hand torque

Mohammad Sadegh Sohrabi

Introduction: The weak design of hand tools and their disharmony with the user's physical features comprise a major risk factor for upper limb musculoskeletal disorders. Hand-tool related injuries comprise almost 9% of all work-related injuries. The present study was conducted to examine the effect of hand tools' diameter on comfort and maximum hand torque and to estimate the optimal diameter for hand tools.

Methods: Participants included 6 men and 6 women with a mean age of 24.7 and a standard deviation of age of 5.84 years. Participants started to load and rotate the grip of 7 hand tools with different diameters with all their power and using a self-made tool for measuring the torque. The test duration, maximum torque and comfort level of the tool grip was then measured and the data obtained were analyzed using the ANOVA and the t-test.

Findings: The mean maximum torque value obtained was 1.88 (SD=0.95) newton meter, the time taken to reach the maximum torque was 13.96 (SD=9.03) seconds and the mean comfort level was 3.27 (SD=1.48) at a scale from 1 to 7. There was a significant difference between the maximum torque generated in the group of men and the group of women (p<0.001). The mean maximum torque obtained was 3.034 newton meter and the mean maximum comfort level was 4.67, achieved with a grip diameter of 38 mm.

Conclusion: The optimal hand tool diameter recommended for maximum user comfort and torque is 38 mm.

The intensity of electromagnetic fields emitted by common compact fluorescent lamps

Mohsen Aliabadi

Introduction: In recent years, compact fluorescent lamps have been more widely used across the country as a means of optimizing energy consumption. Given the health consequences of lighting sources, the present study was conducted to investigate the intensity of electromagnetic fields emitted by common compact fluorescent lamps.

Materials and Methods: The study examined 54 compact fluorescent lamp bulbs manufactured in local and international factories. The intensity of the electromagnetic fields emitted was measured at a very low frequency (VLF) and an extremely low frequency (ELF) using field measuring devices (Holaday HI 3603 and HI 3604 models). The data obtained were analyzed in SPSS.

Findings: The intensity of the emitted electric and magnetic fields decreased with the increase in their distance from the sources. At the reference point of 25 cm, the effective intensity of the electric field was 2.25 v/m at the very low frequency and 15.39 v/m at the extremely low frequency. The intensity of the magnetic fields was 0.47 mA/m at the very low frequency and 9.41 mA/m at the extremely low frequency. All the values were below the national exposure limits. There was a significant difference between the effective intensity of the electric and magnetic fields based on the lamps' manufacturers (p<0.05).

Conclusion: Although the intensities of the electromagnetic fields of the lamps were lower than the exposure limits, due to lack of conclusive evidence on the biological effects of fields, minimizing the public exposure to fields is essential. The use of standard-quality lamps is therefore highly recommended as a preventive measure.