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Showing 7 results for Dianat
Ergonomic Approaches and Challenges in Product Design
Iman Dianat, Parvin Adeli, Amir Hossein Talebian,
Volume 4, Issue 2 (Journal of Ergonomics 2016)
Abstract

Introduction: The importance of product design has been dramatically increased in recent years due to economic considerations as well as changes in user preferences, policy making and legal needs. In response to this, and as one of the most influential branches in the field of product design (in terms of the fit between product and user), ergonomics has also been developed proportionally. The aim of this study was to review the most important considerations and different traditional and new approaches in product design as well as challenges and limitations in this regard.

Methods: A review was made of the relevant electronic databases including Ergonomics Abstracts, PubMed/Medline, Web of Science, Science Direct, Scopus and Google Scholar using the following keywords: product, design, ergonomic, design procedures and design approach. The search was limited to full text articles in the English language, published in peer reviewed journals between 1990 and 2015.

Results: Comparison of the traditional and new approaches in product design indicated that the new approaches helped designers to choose the best product model based on various aspects and a more detailed interaction between user and product. Ergonomic considerations in product design also include engineering and psychological aspects as well as taking into account abilities and limitations of both products and users, to find a good fit between user and product.

Conclusions: The findings suggest that the traditional approaches in product design alone may not anymore guarantee the success of a product in the market, particularly in universal scale and for a wide range of users. In other words, consideration of various technical (in terms of user-product interaction) and legal (environment, sustainability, cost benefit, etc.) aspects in new ergonomic approaches may be taken into account to improve the quality and success of the products in the global market. Ergonomists may encounter with some challenges to achieve this goal, but high-quality ergonomics services can be considered as an effective solution in this regard.


Ergonomic Design and Evaluation of Fabric Cutting Scissors with Regard to Pinch Force and Wrist Posture
Soudabeh Asadollahi, Iman Dianat, Moein Nedaei,
Volume 5, Issue 2 (Journal of Ergonomics 2017)
Abstract
Introduction: Scissors are essential tools in different occupations including sewing and clothes making. Improper design of fabric cutting scissors can lead to the development of musculoskeletal symptoms among users. The aim of this study was to evaluate pinch force and wrist posture while working with three designs of sewing scissors and a traditional sewing scissors.
Methods: The first model of the scissor had a bent-handle (to improve wrist posture), the second model had a thumb-ring that was located closer to the pivot (to reduce thumb’s abducted position and range of movement), and the original oval ring in the third model was changed to a hook-shaped handle (to reduce hand and finger discomfort). Pinch force was measured using a pinch gauge and wrist posture was measured in two anatomical planes including flexion/extension and ulnar/radial deviation using the observational method.
Results: The results showed significant effects of scissors' design on pinch force exertions (P < 0.01) and ulnar/radial deviation of the wrist (P < 0.001). The lowest level of pinch force decrement between pre- and post-pinch force measurements was recorded for the second model (2.4%), while the highest level was recorded for the traditional model (7%). More neutral wrist postures in ulnar/radial direction (83%) were recorded for the first model compared to the other designs.
Conclusions: The second scissors, which was designed to reduce thumb’s range of motion and abduction, showed some improvement in pinch force compared to the traditional model.

Dimensional Accommodation of Common Harvesting Combines’ Seat with Operators’ Anthropometric Characteristics and Proposition the Proper Dimensions Based on Ergonomics Principles
Masoud Feyzi, Hossein Navid, Iman Dianat,
Volume 8, Issue 1 (Iranian Journal of Ergonomics 2020)
Abstract

Background and Aim: Agricultural combine harvesters play a crucial role in cereal productions. A combine operator performs almost all harvesting activities in seated posture. As an interface of the biomechanical system of operator’s body and combines’ mechanical system, seat has major effect on operator’s safety, health, and comfort. A successful design of seat is not achievable without considering the anthropometric characteristics of user population in geometric design. In current study, the accommodation of common harvesting combines’ seat with Iranian operators’ body dimensions has been investigated.
Methods: This study was conducted in Bijar, the widest county of Kurdistan province in the west of Iran. Eight anthropometric dimensions including weight, stature, shoulder height, elbow rest height, popliteal height, buttock-popliteal length, shoulder breadth, and hip breadth were measured on a sample of operators. The accommodation of seat pan width, upper backrest width, lower backrest width, seat height, armrest height, seat depth, and backrest height were investigated based on logical equations.
Results: There was a considerable mismatch between evaluated combine seats and the anthropometric dimensions of operators. Selecting 440, 370, 440, 410, 260, 430, and 415 mm for respectively seat pan width, upper backrest width, lower backrest width, seat height, armrest height, seat depth, and backrest height can increase the match percentage to a range of 62.2% to 100%.
Conclusion: The dimensions of available combine harvester seats are not suitable for Iranian population. However, considering the anthropometric dimensions of operators can improve the seats ergonomically. It should be noted that a design based on corresponding national and international standards cannot guarantee the geometrical accommodation of seats.


Investigating the Relationship Between the Risk of Psychosocial Factors and Grip Fatigue of Employees with Manual Tasks
Neda Mahdavi, Javad Faradmal, Iman Dianat, Hassan Khotanlou, Rashid Haidari Moghadam,
Volume 8, Issue 3 (Iranian Journal of Ergonomics 2020)
Abstract
Backgrond and Aim: Fatigue is a common and highly prevalent problem among workers. Muscle fatigue is the result of general fatigue that is caused by different risk factors. This research was conducted to assess grip fatigue between workers with manual tasks and its relationship to psychosocial risk factors.
Methods: In this study, Jamar hydraulic dynamometer was used to investigate the decrease in the production of grip force or grip fatigue. The grip force of 157 subjects in three job levels that met inclusion criteria recorded, three times in an 8 hours shift. The psychosocial risk factors were also assessed using the Copenhagen psychosocial questionnaire and their relationship with grip force and grip fatigue was analyzed.
Results: sixty-one percent, 62%, and 69% of employees in light, medium, and heavy tasks, respectively, experienced grip fatigue in the second phase of the study. It seems that as the power/speed increased and the tasks became more difficult, employees experienced more grip fatigue in the right hand. The declining trend of grip force and the increase in grip fatigue was more evident in heavy task jobs. No moderate or strong correlation was observed between the psychosocial risk factors and grip fatigue.
Conclusion: Because the nature of worker tasks in heavy manual tasks required more force exertion, they experienced more grip fatigue in their right hand than other workers. It is not possible to draw definitive conclusions about the impact of psychosocial risk factors on grip fatigue. Investigating the impact of cognitive loads and anthropometric dimensions on grip fatigue can be an interesting topic for future studies.

Psychometric Properties of the Persian Version of the Comfort Questionnaire for Hand tools (CQH)
Azam Maleki-Ghahfarokhi, Iman Dianat, Mohammad Asghari Jafarabadi, Mohamad Parnianpour, Mahmood-Reza Azghani, Maryam Khosravifar, Sina Samadi,
Volume 10, Issue 1 (Iranian Journal of Ergonomics 2022)
Abstract
Objectives: The comfort questionnaire for hand tools (CQH) is a subjective measure for exploring the starting points for improving hand tool design. This study aimed to investigate the psychometric properties of the Farsi version of the CQH.
Methods: In this cross-sectional study, which was conducted among 163 university students, the 17-question CQH was translated into Farsi with a translation back-translation procedure. Content validity was assessed by a panel of 10 experts. Exploratory Factor Analysis (EFA) was applied for determining construct validity. Cronbach’s alpha and Intraclass Correlation Coefficient (ICC) were used for assessing internal consistency and test-retest reliability, respectively. Ceiling and floor effects were also estimated for evaluating the feasibility of the measure.
Results: The CQH showed good content validity. Content validity index (CVI) ranged from 0.80 to 1.00 and Content Validity Ratio (CVR) ranged 0.62-1.00. EFA led to extraction of two factors from the data. The first one was mostly related to functionality and physical interaction and the second one, was generally about adverse body effects. The Cronbach’s alpha was 0.74 and test-retest reliability was 0.74 (95% CI = 0.58 to 0.86) which both were satisfactory. There were no (0%) ceiling and floor effects.
Conclusion: The Farsi version of CQH is an acceptable and useful instrument for evaluating hand tools comfort.

Industrial Exoskeletons, Challenges and Suggestions in Ergonomic Studies
Abdollah Vahedi, Iman Dianat,
Volume 10, Issue 2 (Iranian Journal of Ergonomics 2022)
Abstract
Objectives: The challenges that have been raised today, such as changes in population structure, diverse workforce, mass production, and automation of production, indicate the need to review production systems. Classical ergonomic solutions are no longer suitable for carrying heavy loads and repetitive activities. By supporting workers to reduce physical and mental stress, human-centered assistant applications (HCAAs) should solve this problem. The technical problems of the exoskeleton have been investigated in many scientific studies, but its effect on the human user has not been paid much attention to. So, this study reviews the studies that have examined industrial exoskeletons from the ergonomic point of view
Methods: Papers concerning exoskeleton in ergonomic studies are reviewed using Scopus and PubMed databases. The selected papers were published in the reviewed journals from 2014 to 2021. Books, conference papers, and reports are not included in this study. In the present study, only official scientific journals in English are reviewed, and the references obtained from the search are screened by the title and abstract. The full text of the papers is checked if the abstract does not contain enough information. Those papers that met the inclusion criteria are listed in this review.
Results: Studies on ergonomic industrial exoskeletons account for a small share of studies on industrial exoskeletons. From 2012 to the time of conducting this study, 96 studies were found on industrial exoskeletons, of which 10.41% design or evaluate industrial exoskeletons from an ergonomic point of view. This is very small compared to the studies on exoskeleton conducted since 2012 and only about 0.4% of the studies.
Conclusion: The reviewed studies emphasize the facilitation of the successful use of exoskeletons in occupational structures by considering at least three dimensions (physical requirements, task performance, and usability), all of which can contribute to determining the potential efficiency of exoskeletons in the work environment. Due to the potential of this technology, more studies should be conducted in the future to cover some of the identified challenges and compare the exoskeleton design methods under more diverse and more realistic situations.

Evaluation of Muscle Activity when using the Passive Assistive Arm
Abdollah Vahedi, Iman Dianat,
Volume 12, Issue 1 (Iranian Journal of Ergonomics 2024)
Abstract
Objectives: Despite the increasing trend of automation and mechanization in the industry, many workers are exposed to high physical workloads, repetitive motions, and unusual body postures. In this regard, assistive technology (AT) is a relatively new and practical solution. This study was conducted to design an assistive arm according to ergonomic principles and investigate its effect on the electrical activity of shoulder muscles.
Methods: This research was fundamental in its approach, using an experimental intervention method. The investigated samples included students studying in the Tabriz University of Medical Sciences, Faculty of Health in 2021, of which 12 participated in the study, half of whom were female and half were male. A prototype of a passive assistive arm was first designed. The electrical activity of muscles was then evaluated at two work heights and two tasks in a simulated workstation with and without the use of an assist arm. The data were analyzed at a significance level of 0.05 using SPSS26 software.
Results: The designed assistive arm reduced the electrical activity of the muscles in the tested heights and tasks, and among the six investigated muscles, the activity of the trapezius and anterior deltoid muscles decreased the most.
Conclusion: According to the results, the designed assistive arm reduces the electrical activity of the shoulder muscles and differentially affects different tasks and work heights. The results generally indicate that the use of an assistive arm can be an effective intervention for overhead tasks.

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