welding arc welding or other welding mechanisms the position of the rod and length of the rod are determined by the specific catalyst disk design in the example reactor the rod is centered on the width of the catalyst disk the diameter of the rod is determined by the total ampacity used in the final reactor design when all catalyst disks are assembled and run at the reactor operating temperature the resistance wire is wound around the rod the pitch or spacing between adjacent windings in the spiral is determined by the desired watt density of the heating element this watt density is determined by cfd computational fluidic dynamics of mass flow through the catalyst disk in our example the pitch is 0 071 u2033 with 25 turns the width of each catalyst disk sections is determined by the kinetics of the reaction if the removal of heat energy from the catalyst is below the heat contributed by the heating elements to make the desired reaction go forward then that reaction length determines the width of that catalyst disk core section in other words the width of the catalyst disk is governed by how much heat is removed from the catalyst heating element since various molecules have different heat capacities this length can be calculated for a specific reaction and catalyst reaction.