Resistance projection welding is used to simultaneously weld two thin, steel plates together at four locations. One of the pieces of steel plate is preformed with projections that have a diameter of 0.25 in and a height of 0.20 in. The duration of current flow during the weld is 0.30 sec and all four projections are welded simultaneously. The plate steel has a unit melting energy of 140 Btu/in3 and a resistance between plates of 90.0 micro-V. Experience has shown that 55% of the heat is dissipated by the metal and 45% melts the weld nugget. Assume the volume of the nuggets will be twice the volume of the projections because metal from both plates is melted. How much current is required for the process?