Stimuli are signals that trigger the senses. Receptors detect the stimuli and neurons send the signals to the brain where they're interpreted. Each sense organ includes receptors that capture relevant stimuli for transmission to the brain. The receptors in the skin are mechanoreceptors and thermoreceptors.
AWWA Butterfly valves are quick opening valves that consist of a metal circular disc or vane with its pivot axes at right angles to the direction of flow in the pipe, which when rotated on a shaft, seals against seats in the valve body. They are normally used as throttling valves to control flow.
However, newer cars have the means of adjusting the flow of air through the intake in relation to driving conditions. These vehicles are equipped with intake manifold runner control modules, which are vacuum solenoids that operate a butterfly valve in the intake. During slower driving when the need for air is less, the butterfly stays closed.