Habibollah Dehghan, Aioob Ghanbary Sartang,
Volume 2, Issue 4 (3-2015)
Abstract
Introduction: The incidence of heat stress is one of the most common problems in work
environments as well as many different industries. The exposure of workers to heat results
in heat strain. The purpose of the
present study was to validate the Perceptual Strain Index through determining its relationship to the Physiological Strain
Index and the Wet Bulb
Globe Temperature Index under hot laboratory conditions.
Materials and Methods: The present cross-sectional study was
conducted on 15 men in five different temperature conditions (21, 24, 27, 30
and 35ºC) in a climate chamber and on the treadmill with three different
activity levels –light (2.4km/h), medium (4.8km/h) and heavy (6.3km/h).
Participants' heart rate and oral temperature were measured in order to
calculate the Physiological Strain Index, and their thermal sensation and the rate of
perceived exerted activity were measured for calculating the Perceptual Strain
Index. The correlations between the indices were then evaluated using Pearson's
correlation test and the regression analysis.
Results: Pearson's correlation test showed a significant correlation between
the Perceptual Strain Index and the Physiological Strain
Index (P=0.001 and r=0.94). The Perceptual Strain Index was also found to have a significant
correlation with oral temperature and heart rate (p=0.001
and r=0.78 (p=0.001 and r=0.90). In addition, a significant correlation was found
between the Perceptual Strain Index and the Wet Bulb Globe Temperature Index (p=0.001 and
r=0.71) however, no relationship was observed between the
Perceptual Strain Index and the Body Mass Index (p=0.79 and r=0.0009).
Conclusion: The findings of the
study showed that the Perceptual Strain Index can be used for evaluating heat
strain in the absence of access to other methods of evaluating heat stress as
it has an acceptable correlation with valid indices of heat stress.
Zahra Sharifi, Reza Osqueizadeh, Seyyed Farhad Tabatabai Ghomshe,
Volume 3, Issue 1 (6-2015)
Abstract
Introduction: Job satisfaction and productivity among industrial workforce depend on multiple factors. Among these
factors, designing the workstation based on bodily characteristics and dimensions of the workers is of critical
significance. Since industrial chairs have direct impacts on biomechanical and anthropometric compatibility, they play
a major role in enhancing workers’ interaction with their workplace. The current study approached the redesign of such
a product with a focus on ergonomics.
Materials and Methods: The present research was a typical combined design project. In the quantitative phase, 90
participants underwent 12 anthropometric measurements (which were important in designing industrial chairs). The
underlying cognitive aspects of the question were evaluated via qualitative methodologies.
Results: Since normal distribution of the data was confirmed, raw anthropometric data were descriptively processed
and reported. Cognitive assessments revealed correlations between correct form and softness of the backrest, and
appropriate slope of the seat-pan, being a main factor determining the level of comfort while interacting with industrial
chairs.
Conclusion: Diverse physical constraints and conditions caused by the variety of duties and workstations have made it
somehow difficult for specialists to design a universal industrial chair functioning in all different contexts.
Nevertheless, the current study confirmed the effectiveness of involving personnel in redesigning the workplace and
easing the challenges.
Mansour Ziaei, Ghobad Rezaei, Hamed Yarmohammadi, Elahe Khoshboo, Faramarz Gharagozlou,
Volume 3, Issue 1 (6-2015)
Abstract
Introduction: Job involvement is defined as one’s psychological dependence on his/her job. Employees with high job involvement
pay more attention to their job. The present study aimed to determine the relationship between teachers’
job involvement and demographic characteristics in Kermanshah (Iran) secondary
schools during 2013.
Materials and Methods: This cross-sectional study was
performed on 211 teachers (161 male and 50 female). Data were collected using
the Job Involvement Scale. The collected data were analyzed using Spearman’s
correlation coefficient, independent t-test, and analysis of variance (ANOVA).
P values less than 0.05 were considered significant.
Results: The teachers’ mean age and work experience were 32.21 and
8.49 years, respectively. Low, moderate, and high levels of job involvement were
detected in 22.3%, 54.5%, and 23.2% of the teachers, respectively. Job
involvement was significantly higher in married teachers than single subjects
(p = 0.027). Moreover, teachers without a second job had higher job involvement
than those with a second job (p = 0.006). There were no statistical
correlations between job involvement and age, sex, work experience, or level of
education.
Conclusion: The participating teachers
generally had low-moderate levels of job involvement. Low salary, working
multiple jobs, and low social prestige were mostly responsible for such low
levels of job involvement. Therefore, increasing teachers’ salary, providing
teachers with special facilities (e.g. low-interest loans), and developing a system
for teachers’ promotion (similar to that existing for faculty members) can be
effective in increasing job involvement among teachers
Parisa Hosseini Koukamari, Abdolzahra Naami, Teimour Allahyari,
Volume 3, Issue 1 (6-2015)
Abstract
Introduction:
Adaptive performance is defined as an employee’s ability to deal with changes and new and unusual situations
in the workplace. The present study
mainly focused on factor analysis of the Adaptive Performance Scale (APS) and
determining its validity and reliability. Adaptive
performance is a multi-dimensional
structure with five
latent factors.
Materials and Methods: This method
validation study was conducted in Ahvaz, Iran. 210 randomly selected
public hospital nurses completed the Persian version of the APS. Exploratory factor analysis (varimax rotation) was used to explore the
factor structure of the scale. Confirmatory factor analysis and structural equation modeling were applied
to fit the model.
Results: The
overall reliability of the APS was confirmed (Cronbach’s alpha = 0.89). Factor
analysis was used to evaluate the factor structure of the scale. Kaiser-Meyer-Olkin index (0.88) and
Bartlett's sphericity test result (1639.093) were both significant.
Finally, varimax rotation showed all items to have significant factor loadings.
Conclusion: Our findings
confirmed the acceptable psychometric properties (reliability
and validity) of the APS for administration among nurses. Therefore, the
adaptive performance construct contains five distinct dimensions, namely dealing with emergency and
unexpected situations, work stress
management, creative problem solving,
learning, and interpersonal adaptability. These results are consistent
with previous studies.
Athena Rafieepour, Elnaz Rafieepour, Marzieh Sadeghian,
Volume 3, Issue 1 (6-2015)
Abstract
Introduction:
Musculoskeletal disorders are one of the leading problems among computer users.
They have attracted increasing attention over years and different solutions
have been proposed for their resolution. This study evaluated the effects of ergonomic
training on reducing the risk of musculoskeletal disorders in computer users.
Materials and Methods: This study was conducted
among the office workers of a university. A total of 110 computer operators
were randomly selected and allocated to intervention and control groups. The
intervention group was trained about the ergonomic principles of working with
computers. Nordic
Musculoskeletal Questionnaire (NMQ) was used to investigate the prevalence of musculoskeletal
disorders. Moreover,
rapid upper limb assessment (RULA) was applied to determine the risk of
musculoskeletal disorders before and six months after training. Data was analyzed using independent
and paired t-test.
Results: The
highest frequency of
musculoskeletal disorders was seen in the back (55.4%) and neck (54.5%). In
addition, risk assessment before the intervention suggested 31% of the
participants to be high-risk. After the training program, significantly lower
risk was detected in the intervention group. No such a significant difference
was present in the control group.
Conclusion: The
results of this study showed that corrective actions can reduce the risk of
work-related musculoskeletal disorders (WMSDs).
They can thus be implemented to enhance
the effectiveness of ergonomic measures.
Farideh Dehghan Manshadi, Gholamreza Haj-Valie, Rashid Heydari Moghadam, Khosrou Khademi Kalantar, Alireza Yavari Kia, Manoochehr Karami,
Volume 3, Issue 1 (6-2015)
Abstract
Introduction: Concurrent pain in
the knee joint and its-related muscles is expectable in patients with
sacroiliac dysfunction. However, the association between the severity of knee
pain and the level of sacroiliac dysfunction is still unclear. The present
study aimed to determine the association between the severity of sacroiliac
dysfunction and the severity of pain due to involvement of knee compartment.
Materials and Methods: One hundred
consecutive patients who visited an orthopedic clinic with the primary
complaint of knee pain were recruited. According to specific diagnostic tests, 50
had sacroiliac dysfunction and 50 had no history of sacroiliac dysfunction. The
severity of knee pain was determined using the Anterior Knee Pain Scale (AKPS).
T-tests were then performed to compare the two groups in terms of AKPS scores.
Results: The mean AKPS score
was 33.2 ± 12.1 in patients with sacroiliac dysfunction and 62.6 ± 18.6 in
those without sacroiliac dysfunction (p < 0.001). Moreover, anterior knee
pain was more frequent in the first group (56% vs. 10% p < 0.001).
Conclusion: There is a
significant association between the severity of anterior knee pain and severity
of sacroiliac dysfunction. This association may be due to involvement of knee
extensor muscles following the progression of sacroiliac dysfunction.
Fozieh Javadpour, Sareh Keshavarzi, Alireza Choobineh, Mandana Aghabaigi,
Volume 3, Issue 1 (6-2015)
Abstract
Introduction: Perceived work-related
fatigue is an important issue since it may adversely impact workers’
performance. Additionally, workers’ fatigue is known as a main cause of
occupational accidents in workplaces. Considering the consequences of perceived
work-related fatigue, assessing fatigue at workplace is critical to
work-related fatigue risk management. Therefore, this study assessed the
validity and reliability of the Persian version of the Swedish Occupational
Fatigue Inventory (SOFI-20) among Iranian employees.
Materials and Methods: In this cross-sectional
study, 501 employees of two petrochemical companies were selected by simple
sampling method. The Persian version of SOFI-20 was developed using forward and
backward translation processes and used to collect the required data. The
validity and reliability of the translated inventory were examined by
confirmatory factor analysis (CFA) and Cronbach’s alpha coefficient,
respectively.
Results: Assuming
that some items of the Persian version of the SOFI-20 were correlated, the
confirmatory factor analysis was repeated to achieve better fitness. The results of CFA revealed an acceptable fit for the
Persian version of SOFI-20. The total Cronbach’s Alpha coefficient for the
SOFI-20 was 0.95. Cronbach’s alpha coefficients for different dimensions of the
SOFI-20 were found to range from 0.690 to 0.887.
Conclusion: The validity and
reliability of the Persian version of the SOFI-20 was acceptable for assessing
the dimensions of work-related fatigue among Iranian employees.
Raziyeh Morshedi, Matreh Boazar, Davood Afshari, Kambiz Ahmadi Angali, Maryam Malek Zadeh,
Volume 3, Issue 1 (6-2015)
Abstract
Introduction: Manual handling of loads and carrying tasks widely exists in many occupations. Hospital staff because of Manual carrying of loads, are at increased risk of musculoskeletal disorders. Incorrect lifting methods, is an important risk factor for low back pain. The aim of this study was to analyze the biomechanical loads on the lumbar of nurses-aid in manual handling activities of serum cartons 12.5 kg in hospital and provide ergonomic solutions is the prevention of back pain.
Methods: This study was conducted one of the hospitals in Ahvaz city in year 1392. evaluated Postures were sampled through observation and photography. Then load lifting of complex index, was calculated by NIOSH equation and estimate the compressive forces on vertebras L5/ S1 as a quantitative index using software 3 D SSPP, during 2 stages before and after the intervention. The results of tests using Correlation, Regression and T-test were analyzed
Results: The results showed that the highest RWL in the top row 89/9 kg and minimum on the bottom row was 44/5 kg. The highest and lowest compressive force was estimated in the bottom and top rows, respectively, 6727 and 3707 Newton. Results of statistical tests showed significant reduction between the load lifting of complex index(CLI), and the compressive force average before and after the reform is the work station.
Conclusion:Throgh biomechanical analysis of work stations with two methods quantitatively and qualitatively can be made more accurate assessment and ergonomic conditions at work stations can be modified more accurately.
Mahtab Azizi, Mohsen Aliabadi, Rostam Golmohammadi ,
Volume 3, Issue 2 (9-2015)
Abstract
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.
Mahsa Bagheri, Abasali Shahrudi,
Volume 3, Issue 2 (9-2015)
Abstract
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.
Narmin Hassanzadeh-Rangi, Yahya Khosravi,
Volume 3, Issue 2 (9-2015)
Abstract
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.
Leila Gheibi, Mohammad Ranjbarian, Hossein Hatami, Soheila Khodakarim,
Volume 3, Issue 2 (9-2015)
Abstract
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.
Naser Sadra Abarghouei,
Volume 3, Issue 2 (9-2015)
Abstract
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.
Mohammad Sadegh Sohrabi,
Volume 3, Issue 2 (9-2015)
Abstract
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.
Abdullah Hayati, Afshin Marzban, Mohammad Amin Asoodar,
Volume 3, Issue 3 (12-2015)
Abstract
Introduction: Despite the introduction and development of agricultural mechanization in the dairy farm sector of Iran, many tasks are still performed by manual labor in the country’ dairy farms, including milking, and necessitate poor body postures and movements that help increase the risk of musculoskeletal disorders among hand milking workers.
Material and Methods: The present study was conducted to assess the postural workload of workers during hand milking in the dairy farms of Ramin Agriculture and Natural Resources University and Ramhormoz county. Three milking techniques were assessed, including traditional hand milking, milking stanchion (mobile milking unit) and tandem parlor milking (the double-3 tandem). The postural workloads of 34 male milking workers were evaluated through mixed-methods.
Results: The results obtained showed that hand and stanchion milking require major parts of the body to be in a bent position over 70% of the time due to the operations taking place at a low height from the ground. In contrast, tandem milking required the body to be in a straight position over 90% of the time due to the operations taking place at a substantial height from the ground. Moreover, in terms of finger posture, all three techniques required the workers’ five fingers to be wrapped around different milking tools and parts of the cattle throughout the processes.
Conclusion: Being bent for long periods of time during the process of hand and stanchion milking and standing upright for long periods during tandem milking both caused musculoskeletal disorders of the back and backache for workers of both traditional and mechanized milking. In the case of the finger posture, prolonged repetitive finger postures decrease for milking workers with the increased mechanization of milking.
Tahereh Gholami, Ahmad Heidari Pahlavian, Mehdi Akbarzadeh, Majid Motamedzade, Rashid Heidari Moghadam,
Volume 3, Issue 3 (12-2015)
Abstract
Introduction: As workplaces, hospitals are filled with stressors, including environmental and physical stressors (such as noise pollution and poor lighting), human stressors (such as conflicts with colleagues) and organizational stressors (such as heavy workloads and unsuitable work shifts). The inability to cope with these stressors entails physical, psychological and behavioral outcomes for the employees. The present study was conducted to evaluate job stress in nursing personnel and to design a model for assessing the severity of musculoskeletal disorders caused by job stress among nurses.
Materials and Methods: The present cross-sectional analytical study was conducted on 500 nurses working in various teaching hospitals of Hamadan. Data were collected through four questionnaires, including the Job Content Questionnaire, Maslach’s Burnout Inventory, the Visual Analogue Scale and a Demographic Questionnaire. Data were then analyzed in SPSS-16 and LISREL-8.3 using descriptive statistics.
Results: The results of the structural equation modeling showed that job burnout has a mediating effect between the severity of musculoskeletal disorders and job stress. In other words, if factors contributing to job burnout are present, the psychosocial risk factors yielded by the Job Content Questionnaire then contribute to the severity of musculoskeletal disorders.
Conclusion: Given the negative effects of job stress among nurses, health decision-makers are recommended to take measures to reduce stressors such as the physical and psychological demands of the workplace, the lack of support and the lack of job security.
Teimour Allahyari, Sholeh Jafari, Hamidreza Khalkhali,
Volume 3, Issue 3 (12-2015)
Abstract
Background: Power and pinch hand grip strengths are major clinical and ergonomic parameters contributing to the hand muscle power. The data on hand grip strength measurements can have many benefits, including application in the design of hand tools. The present study was conducted to measure power hand grip strength among male and female students aged 19 to 36 using a Jamar Dynamometer and to compare their measurement data with the data obtained from other groups of the population.
Materials and Methods: The present cross sectional study was conducted on 234 male and female students aged 19-36 in Urmia University of Medical Sciences. Hand grip strength was measured using Jamar hand dynamometer and according to the Southampton protocol for adult grip strength measurement.
Results: The mean (±standard deviation of) hand grip strength calculated was 44.39 (±9.71) in the male students 20.48 (±5.86) in the female students. A high correlation was observed between the power hand grip strength in the left and right hands (r=0.94 and P<0.001) and a significant difference then between the power hand grip strength in the dominant and non-dominant hands.
Conclusion: The findings of the present study and similar studies about power hand grip strength in the Iranian population can be used by ergonomists and manufacturers to improve the design of hand tools and the performance of tasks requiring hand muscle power.
Mohammad Amin Mououdi,
Volume 3, Issue 3 (12-2015)
Abstract
Introduction: An important measure for ensuring safety in the operation of industrial machinery is to install proper guards that prevent machine hazards and protect operators. The design of industrial machine guards is a key issue in ergonomics and worker safety and has become a focus of research in hand anthropometry.
The present study was conducted to assess the different hand anthropometric dimensions of employees in an industrial unit and to design a fixed mesh guard in the shape of a rectangle for industrial machines and to use the collected data for the standardization of industrial machine guards in Iran to help prevent machine hazards.
Materials and methods: Thirteen right hand anthropometric dimensions of 97 male and female employees of an industrial unit were examined. To design a standard fixed guard, the length dimensions of the 99th percentile of men and the thickness (diameter) and width of the 1st percentile of women were calculated.
Results: According to the data obtained, a standard fixed guard creates a safe distance of 196.61 mm with the hazardous components of the machine, a gap length of 10.19 mm and a gap width of 8.29 mm. Comparison of 6 parameters, including DIP, PIP, MCP, TE, DPC and WR, with the OSHA regulations showed that PIP and WR had decreased, MCP, DIP and TE had increased and DPC could not be analyzed given the lack of sufficient information on the parameter in the OSHA.
Conclusion: The design of machine guards that help prevent industrial hazards is an integral part of workplace safety. The analysis of DIP, PIP, MCP, TE, DPC and WR in the present study and in a study conducted by Vaillancourt et al. showed some of the parameters to have increased and some to have decreased compared with the OSHA regulations. This study also reveals the need for revising ISIRI 11800, a standard published by the Institute of Standards and Industrial Research of Iran.
Shirazeh Arghami, Maryam Moradi, Fatemeh Habibi,
Volume 3, Issue 3 (12-2015)
Abstract
Background: Driver’s fatigue is a major factor contributing to the prevalence of road accidents. A vast number of city dwellers in most countries use public transport bus services to move around the city. Driver’s fatigue causes job burnout and affects the risk of a traffic accident injuring the public. Several methods have been used to date for evaluating mental fatigue however, using questionnaires tends to be a less time-consuming and more accessible technique. The present study was therefore conducted to develop a mental fatigue questionnaire for public transport bus drivers.
Materials and Methods: The study was conducted based on the criteria used for qualitative research. Semi-structured interviews were held with public transport bus drivers using probing questions and data were collected until their saturation so as to enable access to a direct description of mental fatigue by the bus drivers. Data saturation occurred with 30 interviews and sampling was then discontinued. The analysis of the interviews led to the extraction of the themes and an initial list of questionnaire items was then developed. The psychometric properties of the questionnaire were then evaluated through examining the content validity and internal consistency of the items. The content validity of the items was calculated using Lawshe’s table. A minimum CVR of 0.99 and a minimum CVI of 0.75 denoted an acceptable content validity for the items. To determine the internal consistency of the items, 200 bus drivers completed the final version of the questionnaire. The data obtained were then analyzed in SPSS-16 using Cronbach's alpha to measure the reliability of the questionnaire and considering an acceptance level of 0.7.
Results: The interviews conducted at the beginning of the study with 30 drivers led to the emergence of an initial list with 26 items. A total of 9 items with a CVR less than 0.99 were omitted from the list and 17 items with adequate simplicity, clarity and correlation between them and which had a minimum CVI of 0.75 were kept. The questionnaire had a Cronbach's alpha value of 0.87 and was therefore considered a reliable tool.
Conclusion: The questionnaire developed in this study has a good validity and reliability and can therefore be used to assess mental fatigue in public transport bus drivers.
Hamidreza Mokhtarinia, Asrin Shafiee, Marzieh Pashmdarfard,
Volume 3, Issue 3 (12-2015)
Abstract
Introduction: Musculoskeletal disorders are among the top 10 injuries accounting for absence from work. The Extended Nordic Musculoskeletal Questionnaire (NMQ-E) is one of the many tools used to examine these disorders. The present study was conducted to translate and localize the NMQ-E and to evaluate the face validity and test-retest reliability of its Persian version.
Materials and Methods: The present non-empirical methodological study used the International Quality Of Life Assessment (IQOLA) approach to translate the NMQ-E into Persian. The face validity of the Persian version was examined in a sample of 15 patients with musculoskeletal disorders (MSDs) and its absolute and relative test-retest reliability were examined in a sample of 48 patients using the Standard Error of Measurement (SEM) and the Intra-class Correlation Coefficient (ICC). The Kappa coefficient was also used to measure the inter-rater agreement for nominal variables.
Results: The translation and localization of the NMQ-E was deemed easy and acceptable. All the items of the questionnaire had an acceptable face validity. The Intra-class Correlation Coefficient and the Standard Error of Measurement of the Persian version of the NMQ-E were deemed acceptable (SEM=0.56-1.76 and ICC>0.7) and the Kappa coefficient was calculated as 0.78-1.00.
Conclusion: The Persian version of the Extended Nordic Musculoskeletal Questionnaire showed an acceptable validity and test-retest reliability for assessing musculoskeletal disorders in Iranian patients.
