Investigating the effect of hot and cold polyurethane foam on reducing whole body vibration of forklift operators.

Background: Vibration is one of the harmful factors for forklift drivers. The use of non- standard seats and not paying attention to how the seats are maintained can be affected by the amount of vibration transmitted to the person.

Objective: This study investigates the amount of vibration transmitted from the forklift and the effect of different types of polyurethane foam in reducing the vibration transmitted from the forklift seat.

Assessment of contrast perception of obstacles in a tunnel entrance.

The purpose of this study was to assess the contrast perception of obstacles in a tunnel entrance which was placed in Ilam Province, Iran. An obstacle with the reflection coefficient of 20% was mounted at the entrance of thetunnel and then, the car was placed near the tunnel entrance and the intrinsic luminance of the road (L) and obstacle (L) were measured inside the car using the luminance meter. Intrinsic luminance of obstacle and road at the entrance of the tunnel were measured as 41 and 17 cd/m, respectively.