Evaluating the impact of different hard hats on the peripheral vision of construction workers.

Construction safety is always an issue for construction workers. Hence, personal protective equipment plays a critical role in avoiding potential hazards on construction sites. Among these, hard hats protect against head contact with falling objects on construction sites. This study aims to examine the effects of hard hats with different peak lengths on the field of view at different angles in the upward part and to examine the effects of possible field of view losses caused by the hard hat on the reaction times of the workers. A questionnaire was designed and administered to the construction workers. Experiments were then conducted with a group of subjects to assess their peripheral vision level as well as reaction times. The study found that peripheral vision is affected by the peak size of hard hats. The study further revealed that there is a significant relationship between reaction times and hard hat peak size.

Suitability Study of Using UAVs to Estimate Landfilled Fly Ash Stockpile.

The decrease in fly ash production due to the shift in coal industries toward a green environment has impacted many concrete industries as fly ash is a significant component in cement and concrete. It is critical for concrete industries to identify the availability of fly ash in landfills to meet their demand if the supply decreases. This paper aims to analyze the suitability of UAVs in determining the fly ash stockpile volumes. A laboratory test is performed to validate the proposed UAV method. Then, a real quarry site is selected to demonstrate the suitability in a large scale. The results indicate that the UAVs estimate the most accurate volume of the stockpile when the flight height is about five times the stockpile height. A considerable range of 3.5-5 times the stockpile height is most suitable for quantity takeoff. The findings of this study provide a recommendation for choosing the most appropriate technology for the quantitative estimation of fly ash in existing landfills on a large scale.