Annual deaths from tornadoes, earthquakes and floods together total fewer than 200. The most deadly heat wave in recent years occurred in Chicago over a week in July 1995, when temperatures hovered around 100 degrees.
Cardiac Cycle: 1st Systole Phase. During the systole phase, the right ventricle receives impulses from the Purkinje fibers and contracts. The atrioventricular valves close and the semilunar valves open. The de-oxygenated blood is pumped into the pulmonary artery.
The function of force-guided contacts is to enable the safety circuit to check the status of the relay. Force-guided contacts are also known as positive-guided contacts, captive contacts, locked contacts, mechanically linked contacts, or safety relays.