Abstract: A method is provided for making a four-piece hollow airfoil. Four metal sheets are preformed into initial shapes. The sheets are sealed together into two pairs or sub-assemblies. Internal cavities are formed in one sheet from each pair prior to sealing. Each sub-assembly is subjected to high temperature and pressure in order to diffusion bond the sheets together at selected points. The cavities of each sub-assembly are then subjected to internal pressure in order to inflate and superplastically deform the sub-assemblies. The inflated sub-assemblies are combined to form a single assembly and the cavities are again subjected to internal pressure in order to bond the sub-assemblies together. The assembly is then exposed to hot isostatic pressing, after which, excess material is machined off.

Abstract: Reducing NO.sub.x emission levels from a gas turbine combustor having a premixer section by mixing a small portion of air into the fuel prior to injection into the premixer section. The portion of diverted air is approximately five percent of the total amount of air injected into the premixer section or such that the resulting fuel-air mixture in the fuel line is approximately half fuel and half air. The injection of air into the fuel line, referred to as "head start partial premixing," is effective to reduce the fluctuations and nonuniformities in the fuel concentration levels which increase NO.sub.x output.

Abstract: An actively shielded refrigerated superconductive magnet is provided. The magnet includes a generally cylindrical vacuum vessel having an axially extending bore. A plurality of superconductive main coils are positioned in the vacuum vessel concentrically surrounding and spaced away from the bore. A pair of superconductive shield coils having a larger diameter than the superconductive main coils are situated in the vacuum vessel, concentric with the superconductive main coils. The superconductive shield coils are situated at either end of the superconductive main coils. The superconductive shield coils and the superconductive main coils are electrically connected to one another so that the superconductive shield coils and the superconductive main coils are capable of carrying current in opposite circumferential directions. A thermal shield encloses the superconductive main and shield coils, with the thermal shield spaced away from the vacuum vessel and superconductive main and shield coils.