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Showing 3 results for Razavi
Measurement of the Torque Demand for Jar opening and its Relationship with Anthropometric and Physiological Factors
Mehrdad Ashrafi, Hamideh Razavi,
Volume 5, Issue 1 (Journal of Ergonomics 2017)
Abstract

Introduction: Nine percent of all available packaging are jars with steel lids. However, some consumers have trouble with jar opening. The aim of the current research was to analyze the exerting force on jar lids regarding the torque input to the anthropometric and physiological characteristics of the consumers.

Methods: In this study, the force distributed on the fingers and the palm was examined using a special tester consisting of Force Sensing Resistors (FSR). This tester included 19 sensors, 14 of which were installed on the fingers and 5 on the palm. Each sensor was connected to a driver via 2 wires and then to a computer by a USB port. A full jar with 1100 g weight and 85 mm lid outer diameter was used and the forces exerted by 20 participants, including 10 male and 10 female students, was recorded. Next, the Minitab 17 software was used and the mathematical relationship between the torque and anthropometric and physiological characteristics was investigated.

Results: It was found that the force is mainly exerted by the index finger. The calculation of the torque based on the force measurements showed that the maximum torque applied by males was 10.63 Nm and by females was 7.66 Nm. Statistical F test for the torque (response variable) at a significance level of 0.05 resulted in P values equal to 0.011 and 0.008 for male and female participants, respectively. Therefore, it can be concluded that the measured values are statistically significant.

Conclusions: Statistical analysis revealed that hand dimensions and grip strength play major roles in applying torque. Additionally, the results indicated that packaging conditions for the particular jar in this study must be adjusted such that the consumers with the lowest physical ability (5.11 Nm torque) could open them.


Identification and Evaluation of Fault in Human-Machine Interactive System using CREAM Technique and Fault Tree Analysis
Nooshin Atashfeshan, Prof Mohammad Saidi-Mehrabad, Hamideh Razavi,
Volume 9, Issue 3 (Iranian Journal of Ergonomics 2021)
Abstract
Background and Objectives: Despite contribution to catastrophic accidents, human errors have been generally ignored in the design of human-machine (HM) systems and the determination of the level of automation (LOA). This paper aims to develop a method to estimate the level of automation in the early stage of the design phase considering both human and machine performance.
Methods: A quantitative method is used to evaluate the performance of the whole human-machine system by the human-in-the-loop fault tree analysis while a qualitative and cross-sectional method is used to estimate human errors using the CREAM technique. The data are collected from real cases that happened in the control room of the Ferdowsi power plant.
Results: Full automatic option with an average error of 0.013 had the lowest error rate, i.e. 1/8 of the error rate of the manual design. In addition, the CREAM analysis showed that the control room operators were not satisfied with the availability of procedures and Man-Machine Interface and operational support in general. Thus, on average, the reliability of the manual design is less than the reliability of the automatic setting.
Conclusion: High machine reliability has led to the fact that the fully automatic design would be one of the best design choices for human-machine systems. However, based on the previous studies, high automation may have some human-out-of-the-loop shortcomings. Thus, this study proposed solutions to overcome these disadvantages based on the importance of the control parameters or the essence of human involvement in some decision-making and execution tasks.

Evaluation of the Level of Comprehension of the Symbols on the Iranian Washing Machine by the Visitors to Saraye-Irani in the City of Qom
Leila Sadat Razavi Manesh, Kamal Azam, Seyed Abolfazl Zakerian, Payam Khanlari,
Volume 11, Issue 3 (Iranian Journal of Ergonomics 2023)
Abstract
Objectives: Signs and symbols are used to inform how different tools work. Considering that washing machines are a widely used device and tool in today's life, the present study was conducted to determine the level of comprehension of “Saraye-Irani” visitors regarding the symbols placed on Iranian washing machines.
Methods: The number of 300 people who referred to "Seraye-Irani" located in Qom city participated in this study. A researcher-made checklist based on the ISO 9186-1 2007 standard was used to collect the required data. After the checklist was approved by the experts, it was distributed among the participants and they were asked to write down the meaning of each symbol in front of it. The gathered data were analyzed in SPSS version 22 software using the Chi-square and Fisher's tests.
Results: The results showed that the symbol of "wrinkle-free washing" with a comprehension rate of 70% was the only symbol that the participants had a good comprehension of. However, the participants' comprehension of the other 13 symbols in question was below the standard level. The understanding of symbols of "extra rinse" (P=0.016), "cold water wash" (P=0.037), "child lock" (P=0.001), and "full power wash" (P=0.044) decreased with increasing age. Moreover, individuals with higher education levels had a better understanding of symbols (P=0.001).
Conclusion: Among the 14 symbols measured in the present study, only one symbol had an acceptable level of comprehension. Therefore, according to the widespread use of washing machines, to optimize the use of this tool, it seems necessary to design and implement the necessary training to familiarize and understand these symbols.

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