Abstract: A method of reducing noise from a combustor of a gas turbine engine includes the steps of establishing a maximum noise limit that may be for a particular frequency range. A primary fuel flow percentage, which may be emitted from a fuel nozzle arrangement having various groupings of simplex and duplex nozzles, is then established. An immersion depth measured between an aft rim of a swirler and a distal tip of the fuel nozzles may then be reduced thereby reducing the noise amplitude.

Abstract: The oil splitting properties of otherwise conventional alkaline cleaning solutions that comprise water, an alkaline builder, and a general surfactant component are substantially improved by adding a special, nonionic, surfactant component that has an HLB value in the range from 1 to 7.9 and is made up of molecules that contain at least two nitrogen atoms per molecule and have a chemical structure that can be made by sequential additions of ethylene oxide followed by propylene oxide, or of propylene oxide followed by ethylene oxide, to core molecules that are most preferably 1,2-diaminoethane but more generally may be any organic amine that contains at least two primary and/or secondary amino groups and contains not more than 22 carbon atoms.

Abstract: A process for forming a chromium/silica/phosphate protective conversion coating on a metal surface is improved by pretreating the surface with a composition comprising at least one of (i) H.sub.2 TiF.sub.6, (ii) H.sub.2 SiF.sub.6, and (iii) a derivative of poly{alkenylphenol} before applying the conversion coating. The process of the invention results in a protective base coating having superior adhesion to paint at a relatively high coating weight which is desirable for improved corrosion resistance. This process is especially useful in forming such protective conversion coatings on continuous cast aluminum surfaces.

Abstract: In a process for plating or etching metalization patterns on the surface of a three dimensional substrate, a flexible plastic mask is fabricated by first coating the surface of a thin plastic sheet with vacuum formable ink. The mask is then molded into the shape of the surface into which the pattern is to be formed. A low power YAG laser is used to remove areas of the ink through which light is to be allowed to pass. This mask may then be used in either a print and plate process or a print and etch process by drawing the mask into intimate contact with the workpiece by applying a vacuum between the mask and the workpiece. The workpiece may then be exposed to light through the clear areas of the mask.