Schedule a fixed-value source (injection) at a site or sites of a specified continuum layer.
|activeSites||CoordinateSet||Sites that this process should update.|
|layer||String||Continuum layer upon which to schedule injection process.|
|period||Integer||Waiting period between occurrences of this process. period=0 means do only once.|
|start||Integer||Time at which to begin executing this process (specified in integration cycles).|
|value||Double||Value to inject at each affected site.|