The automatic cab signal system shall be arranged so that cab signals will be continuously controlled in accordance with conditions described in Â§ 236.205 that obtain at least stopping distance in advance. Â§ 236.512 Cab signal indication when locomotive enters block where restrictive conditions obtain.
Dissolved oxygen (DO) is a measure of the quantity of free oxygen molecules in water. The concentration of DO is an important indicator of the health of an aquatic ecosystem because oxygen is essential for almost all forms of life. Oxygen is necessary for respiration and for some chemical reactions.
The temperature of the water and the atmospheric pressure must to be known in order to calculate ppm (parts per million) of dissolved oxygen. The oxygen probe contains a solution of potassium chloride (KCl) which will absorb oxygen. As more oxygen is diffused into the solution, more current will flow through the cell.