The ratio of the activity of the SLRDs to the activity of the radon gas is called the Equilibration Ratio (ER). Equilibrium usually occurs in about three to four hours. When an individual receives a dose of one WL in 170 hours (a miner's month), the exposure then becomes called a working level month or WLM.
I imagine it was probably my first Prehospital Trauma Life Support class back in 1990 that I first heard of the three collision rule. Since then, it has remained a useful tool in examining the mechanism of injury after auto accidents. If you havenât heard of it, please allow me to elaborate. The three collision rule states that, in any auto accident, there are three collisions that occur and the keen EMT needs to be aware of all three.
A traffic collision, also known as a motor vehicle collision (MVC) among others, occurs when a vehicle collides with another vehicle, pedestrian, animal, road debris, or other stationary obstruction, such as a tree or utility pole. Traffic collisions may result in injury, death and property damage. A number of factors contribute to the risk of collision, including vehicle design, speed of operation, road design, road environment, and driver skill, impairment due to alcohol or drugs, and behavior, notably speeding and street racing.