فهرست مطالب mostafa rahmiani-iranshahi

Visual comfort is an important and influential factor on safety, mental health, sleep quality, and musculoskeletal disorders of employees in the workplace. This study aimed to design and develop a questionnaire to assess the visual comfort of employees in the workplace.

The study was performed on 101 participants (88 men and 13 women) in the food industry. First, the available lighting questionnaires in the field of lighting were reviewed, and a question bank was collected. Twenty questions were considered in two sections of natural and artificial lighting (10 questions in each section) based on the opinion of 10 experts in this field. The validity of the questionnaire was assessed using the content validity index (CVI) based on the comments of experts. To validate the questionnaire in the workplace, The lighting of employees' workstations was evaluated according to the Illuminating Engineering Society of North America (IESNA) standards and compared with the results of the questionnaire.

The Cronbach's alpha of natural and artificial lighting visual comfort questionnaire was 0.858 and 0.922, respectively. The total CVI of the questionnaire was 1. There was a significant positive relationship between the score of the visual comfort questionnaire and the workstations' illumination (P=0.001). More than 97% of employees who had workstations with the desired lighting reported excellent levels of visual comfort.

The visual comfort questionnaire had good and acceptable reliability and validity. This tool is recommended to assess the visual comfort of employees in work environments due to the small number of questions and simplicity of sentences.

Noise is known as an intruder in job environments and has non-hearing effects. The impact of noise on cognitive functions depends on the type of noise and the dose of noise exposure. This study aims to investigate the effect of noise exposure on cognitive functions and sleep quality.

This descriptive-analytical cross-sectional study was performed on 169 workers in three metal, chemical, and food industries in Hamedan in 1399. A continuous performance test was used to evaluate cognitive functions. The Petersburg questionnaire assessed participantchr('39')s sleep quality. Using SVAN 971 analyzer and TES dosimeter, the level of noise exposure and the dominant frequency was measured. Data were also analyzed using linear and multiple regression in SPSS software (version 16).

There is a significant difference in the level of noise exposure with changes in cognitive functions and sleep quality in the present study (P<0.001). The results of linear regression showed that there is a significant relationship between cognitive function and the level of exposure to sound (P<0.001). After identifying and determining the input variables, using multiple regression, an appropriate model was developed to predict sleep quality and sustained attention in the face of noise.

Based on the results of this study, predictive models with the appropriate coefficient of determination can be good models for assessing the quality of sleep and attention of people in the face of noise, which can be implemented and measured in a shorter time.

Designing workstations in accordance with anthropometric characteristics of employees can prevent awkward working postures and reduce the risk of such disorders. The present study aimed at investigating the anthropometric compatibility of workstations in a sewing company and its relationship with working postures.

This cross-sectional study was conducted in a sewing company located in Hamadan province, Iran. Working postures were assessed in standing and sitting workstations using REBA and NERPA techniques, respectively. Anthropometric dimensions were measured in accordance with ISO 7250 and anthropometric compatibility with workstation was investigated. Mann-Whitney test was used for assessing the relationship between anthropometric compatibility and working posture.

A total number of 205 employees with a mean age 31.29 years old participated in this study. Working postures were mostly in an unacceptable condition and the need for ergonomic intervention was evident. In sitting workstation, there was no significant relationship between working postures and anthropometric compatibility in terms of seat depth, seat width, and backrest height. In contrast, anthropometric compatibility with seat height and desk height were significantly associated with working posture (P<0.05). In standing workstations, a significant relationship was observed between anthropometric compatibility and desk height (P<0.05).

Anthropometric incompatibility with workstation generally deteriorated the working postures. However, anthropometric compatibility with seat height and desk height were the ones with a significant relationship with working posture. Therefore, for redesigning workstations the seat height and desk height should be considered first.