فهرست مطالب bahar parsazadeh

Carbon monoxide is one of the main air pollutants, mainly produced from the incomplete combus tion of fossil fuels. This s tudy aims to oxidize carbon monoxide by copper oxide nanoparticles immobilized on zeolite13X subs trate. The present inves tigation was conducted to determine the effect of carbon monoxide concentration parameters (in the range of 200-1400 ppm) and reaction temperature (in the range of 100-500 °C) on the efficiency of carbon monoxide conversion by CuO/Zeolite 13X nanocatalys t. The design of the experiment and the determination of the number of experiments were analyzed using the central composite design method, and the s tatis tical tes t of analysis of variance was done using the response surface method. Also, the s tructural and morphological characteris tics of the nanocatalys t were inves tigated using BET, BJH, FE-SEM, EDX, and XRF tes ts. The results show that CuO/Zeolite 13X nanocatalys t efficiently oxidizes carbon monoxide. The highes t conversion efficiency of 82.6% was obtained at a temperature of 400 °C and a carbon monoxide concentration of 500 ppm as the optimal conditions. According to the EDX tes t results, copper oxide nanoparticles with a weight percentage of 5.9% were loaded on the Zeolite 13X subs trate. Design Expert11 software reduced the cubic model with an R2 coefficient of 0.98.

Mental workload is an important issue in occupational health. This study aimed to determine the validity and reliability of the Rating Scale Mental Effort (RSME), Integrated Workload Scale (IWS), and Overall Workload Scale (OW) in Iran. This study was conducted on 100 male students of Iran University of Medical Sciences. The forward-backward translation method was used to evaluate the linguistic validity of the scales. Then the scales were presented to six ergonomics and occupational health experts to assess the content validity of the scales. Internal validity of the scales was assessed by correlating mental workload scale scores with reaction times on a criterion task. Finally, multiple sessions of a hybrid memory-search task were performed to determine the reliability of the scales. There was prefect agreement among the experts regarding of all three scales. Content Validity Index and Content Validity Ratio were 1 for each three scales. About the reliability of the scales, the Pearson correlation coefficients between the scale scores in the test and retest phases were 96, 88, and 84 for RSME, IWS, and OW, respectively. Finally, Validity and reliability of the scales were approved and It seems that these scales can be used for measuring self-reported mental workload.

High mental workload is one of the important factors that results in errors in safety and occupational health scope and its measurement has high importance. So, this study aimed to determine validity and reliability of Verbal Online Subjective Opinion (VOSO) and Modified Cooper-Harper (MCH) scales in measuring mental workload.
This study was conducted on 90 male students of Iran University of Medical Sciences. In this study, the Forward-Backward translation was used for translation of scales. Moreover, Content Validity Ratio (CVR) and Content Validity Index (CVI) were calculated by having suggestion of 6 Ergonomics and Occupational health experts. The Hybrid Memory Search Task software was used to create mental workload. Convergent validity of scales was calculated using correlation of scales with reaction time and then Test-Retest method was used to determine the reliability of scales.
Content and convergent validity of scales were confirmed and correlation of both scales with reaction time were higher than 0.8. Moreover for determination of scales reliabilities, Pearson correlation coefficient between scales values in test and retest trials were 0.86 and 0.91 for VOSO and MCH respectively.
It seems that in regard to confirmation of validity and reliability of VOSO and MCH in this study and their high correlation with reaction time, it can use these scales in measurement of mental workload.

Metal industries are of accident-prone industries. Todays the hazard assessment in order to hazard control is very important. Aim of this study was safety and occupational health risk assessment in a metal industry.
This cross-sectional study was conducted in 2014 in Isfahan. Firstly three jobs, forging and fittings cutting and finery press operators, which had highest rate of accidents was selected. Then each task was broken into its subtasks and finally risk assessment using Job Safety Analysis and William Fine methods conducted. Findings analyzed using descriptive and analytical statistics and controlling approaches was delivered.
Assessments lead to identification of 21 hazards in forging, 9 in fittings cutting and 10 in finery press. Highest levels of risks were related to falling hot blocks, error in pushing foot pedal, hands strike to saw blades and environmental noise. Statistical Kruskal walis test showed that no statistical difference found among three jobs, both for Job Safety Analysis and William Fine.
The risk levels of each three jobs was worrying. It seems that applying controlling actions in order to eliminate or decline hazards level is necessary.