صدیقه حسین آبادی

Due to the adverse effects of exposure to electromagnetic waves on humans and equipment, engineering controls such as the use of shields are one of the best ways to control and reduce exposure to electromagnetic waves. There are various methods to evaluate the performance of electromagnetic shields. The aim of this study was to investigate the effect of shield penetration depth and thickness on the performance of nanocomposites.
In this study, paraffin wax was used as a matrix and black carbon spherical nanoparticles and Fe3O4 were used as filler. Two nanocomposite samples were made with different weight percentages of fillers. The electromagnetic properties of nanocomposites made were measured using a Vector Network Analyzer in the frequency range of 8-12.5 GHz (X) based on the transfer/reflection method. The Delta function was used to evaluate the shielding protective performance at different thicknesses and frequencies.
Based on the weight percentage of nanocomposite constituents, two samples were obtained. The highest penetration depth was observed in FN2 samples. Correlation between free space impedance and shield components was observed at the lowest shield thickness and at the initial frequencies. The lowest delta value was observed in the FN2 sample.
According to the Delta function, by increasing the absorption and decreasing the reflection in the shield, the protective efficiency of the shield increases. Shield thickness and frequency of electromagnetic waves affect the protective performance of the shield. Increasing the match of impedance between free space and shielding material increases the shield efficiency.

Nowdays, mental workload is one of the most important issues in the workplaces.Various factors affect the cognitive capacities of individuals which may lead to human errors. Due to the nature of the work and the use of tools and equipment in the tuna fish factory, the risk of accidents increases as a result of human error.The purpose of this study was to investigate the type of accidents and the relationship between the accidents and mental workload in the tuna fish factory. This cross-sectional and descriptive-analytical study was carried out on all of the 48 employees of the Zagros Parsian Factory. Nasa-Tlx questionnaire was used to collect data. Accident statistics were obtained through self-reported and recorded accident documents. Data were analyzed by SPSS software using t-test, linear regression, one-way ANOVA and Pearson correlation. The results showed a significant relationship between sex and the rate of the accidents (P-Value<0.009). The Accident requency Rate (AFR) determined to be 195. The average of the mental workload was higher than the desired 50% level. The mean of accidents in women (27.82) was higher than that of the men (16.46). There was a significant relationship between the frequency of accidents and the total mental workload (P-Value<0.04). This significant relationship was observed in the production saloon (P-Value<0252). Also, regarding the mental workload subscales, there was a significant correlation between the performance and mental workload (P-value<044) and the amount of boredom and mental workload (P-Value<0.0001). According to the results of this study, mental workload is likely to affect the frequency of accidents. Therefore, implementing a program to modify the mental workload, such as revising the work hours and resting periods seems necessary

The purpose of this study is determining of the effectiveness of positive psychology on psychological well-being in mothers of autistic children.

The Statistical population of this research was included all mothers of autistic children that was conducted in Karaj city. Among of visitors, 30 mothers of autistic children were selected as sample with convenience sampling method. Groups of sample were randomly replaced into two groups of experiment (n = 15) and control (n = 15) with quasi-experimental model. In order to gathering data, Ryff scale questionnaires of psychological well-being (RSPWB) and Gilliam (GARS) assessment of autism symptoms was used. The experimental group were trained for 8 sessions of 2 hours.

In order to analyzing the data, analysis method of covariance was used by SPSS software and the results showed that training the positive psychology on psychological well- being in mothers of autistic children is effective. The results of follow-up test also showed that this method has enough stability and sustainability.

The result of this research demonstrates that training the positive psychology can increase the psychological well-being in mothers of autistic children.

Millions of workers in the production or using of different chemicals such as melamine formaldehyde resin are exposed by formaldehyde. In spite of Widespread formaldehyde usage, there are too concerns about its toxicity effects. This study aimed to assess the workers occupational exposure to formaldehyde in some melamine production workshops and blood factors change in the exposed workers.
This cross-sectional study was performed on 66 workers in Tehran. 40 melamine manufactures workers as exposed group and 26 food industry workers as unexposed group was selected. Occupationally exposure to formaldehyde was assessed by NIOSH 3500 method. Hematological parameters including White Blood Cell, Red Blood Cell, Platelet Count, Lymphocytes Percent and Volume of Red Blood Cells was evaluated. Ethical considerations in this study were adhered based on the Helsinki guidelines.
occupationally median exposure to formaldehyde in melamine manufactures was evaluated 0.0896 ppm (0.03-0.2ppm), which is lower than the permitted ceiling limit (TLVc =0.3ppm) in Iran and more than the NIOSH threshold exposure limit (TWA= 0.016 ppm).The results show, in exposed group, workers with unmoral count of white and red blood cells are significantly higher than unexposed people.
Occupationally exposure to formaldehyde cause adverse effects on the hematopoietic system. Exposures to formaldehyde in the concentration lower than approved standard limit in Iran probably induce toxicity effect on the blood cells. Because of the few number of people surveyed in this study, broader studies suggested. In addition assessing blood cells, more specific tests are necessary to evaluate the toxicity effect of formaldehyde on the blood.

The cement industry is one of the most important industries involved in development of countries and also of the most polluting industry work place with harmful agents’ preposition. The purpose of this study was to investigate the workers’ health status in a cement company based on their available medical records. This cross-sectional study is conducted in 2011. In the study, we examined data obtained from 331 workers’ health records (all Shahroud cement company personnel) including their pre-employment, periodical examination and case-specific medical records. Chi-square and independent t-test was used to analyze the data using SPSS version 15. The significance level in all tests was 0.05. Average (Standard Deviation) of age and work history for workers were 40 ±7.5 and12.1 ± 5.5 respectively. Hearing loss (33.5%), cardiovascular disease (18.4%) and musculoskeletal disorders (13.9%) were the most prevalent diseases. statistically significant association was found between cardiovascular diseases (p=0.03) and hearing loss (p=0.002) with job category. Work history was associated with cardiovascular disease (p=0.02), musculoskeletal disorder (p=0.03), renal disease (p=0.003), gastrointestinal disease (p=0.04) and hearing loss (p=0.002). Significant associations were found between age and cardiovascular disease (p=0.007), gastrointestinal disease (p=0.007), and hearing loss (p<0.0001). Working in cement industry may cause hearing loss, high risk of renal diseases and diabetes compared to the normal people. The unsuitable conditions and the harmful work environment are possible causes to workers’ health problems.