(c). Gasifier systems which partially convert fossil or waste fuels (e.g., coal, oil, natural gas or biomass) to syngas and support subsystems, equipment or components thereof, including fuel drying, fuel feed, pulverizers, burners, combustion systems, gasifiers, heat exchangers used in connection with such gasifier systems, pressure parts, boiler cleaning systems, ash systems, valves, controls & diagnostics, other than maintenance and operation services performed as part of overall facility operation and management contracts for domestic or foreign government agencies or entities (including but not limited to NNSA, NASA, DOD, DOE, as well as United Kingdom NDA or MOD sites). (d). Tower-based solar thermal conversion systems which are enabled by solar energy and support subsystems, equipment or components thereof, including receiver system, pressure parts, molten salt or particle systems (e.g., heat exchangers specifically for tower-based solar thermal conversion systems enabled by solar energy or associated pumps or tanks), valves, controls or diagnostics, other than maintenance and operation services performed as part of overall facility operation and management contracts for domestic or foreign government agencies or entities (including but not limited to NNSA, NASA, DOD, DOE, as well as United Kingdom NDA or MOD sites). (e). The following specific unfired heat exchangers Turbine Exhaust Gas boilers (10K2), Heat Recovery Steam Generation Boilers (10K22), Water Tube Waste Heat Boilers Two Drum (Stirling Types) (1K4), 3 Drum Waste Heat Recovery Boiler (1K4), Water Tube Waste Heat "H" Stirling Boiler (1K4), Water Tube Long Drum (LD) boiler (1K4), CO boiler (1K26), Waste Heat (WH) (1K4), Oxygen Convertor Hoods (1K44), Gas Tube (FT) boilers (1K46), FM boilers (1K239), FO boilers (1K2311), Struthers Wells type EOR boiler as defined by the existing specific referenced design standards, or support subsystems, equipment or components thereof, including pressure parts, cleaning systems, valves, controls or diagnostics, other than maintenance and operation services