With some exceptions, an Employee is covered by the HCSO if the Employee works for an Employer covered by the HCSO and: 1  Is entitled to be paid the minimum wage; 2  Has been employed by the Employer for at least 90 calendar days; and. 3  Works at least 8 hours per week in San Francisco.
Vortex ring. Spark photography image of a vortex ring in flight. A vortex ring, also called a toroidal vortex, is a torus-shaped vortex in a fluid or gas; that is, a region where the fluid mostly spins around an imaginary axis line that forms a closed loop. The dominant flow in a vortex ring is said to be toroidal, more precisely poloidal.
A Rogowski coil is a toroid of wire used to measure an alternating current i(t) through a cable encircled by the toroid. The above picture shows a coil encircling a current-carrying cable, with its output terminals v(t) connected to an integrator circuit, to obtain a voltage Vout(t) proportional to i(t) .his type of coil has advantages over other types of current transformers. 1  It is not a closed loop, because the second terminal is passed back through the center of the toroid core (commonly a plastic or rubber tube) and connected along the first terminal.