Abstract: Various embodiments are disclosed for improved and structurally optimized transistors, such as RF power amplifier transistors. A transistor may include a drain metal portion raised from a surface of a substrate, a drain metal having a notched region, a gate manifold body with angled gate tabs extending from the gate manifold, and/or a source-connected shielding. The transistor may include a high-electron-mobility transistor (HEMT), a gallium nitride (GaN)-on-silicon transistor, a GaN-on-silicon-carbide transistor, or other type of transistor.

Abstract: A drivetrain for a multi-spool counter rotating gas turbine engine may include a lay shaft for connecting a power turbine shaft of the engine with a gas generator shaft of the engine when the drivetrain is in engine start mode. In normal operation mode, an actuator disengages the lay shaft, thereby allowing free and independent rotation of the power turbine shaft and the gas generator shaft.

Abstract: A secondary flow, turbine cooling air system for the uniform cooling of high pressure turbine module components such as the turbine shroud, turbine blade tips, turbine nozzle, transion liner, and turbine bearing support housing in a recuperated gas turbine engine is provided. The secondary flow turbine cooling system provides uniform cooling air having a similar pressure and temperature in a recuperated gas turbine engine as the compressor discharge air of a non-recuperated gas turbine engine. A method for uniform cooling of high pressure turbine module components using the secondary flow turbine cooling air system is also provided.

Abstract: A turbine section of an engine that includes a shaft, a plurality of blades extending radially relative to the shaft, a bearing assembly, a flowpath housing, and a shroud is provided. The bearing assembly is mounted to the shaft adjacent to the plurality of blades. The flowpath housing is coupled to the bearing assembly and includes an inner cylinder, an outer cylinder, and a strut. The inner and outer cylinders each include a strut attachment point between which the strut is coupled, and the outer cylinder includes an outer surface. The shroud is disposed concentric to the outer cylinder and has an inner surface including a groove formed therein that is substantially aligned with the outer cylinder strut attachment point. The groove has a depth that provides and maintains a gap between the outer cylinder outer surface and the shroud inner surface when the flowpath housing is exposed to heat and the strut radially expands.

Abstract: A recuperator and turbine support adapter for securing a recuperator to a combustor case is provided. The recuperator and turbine support adapter comprises an outer strutted body, an inner strutted body and a thermal spring. The thermal spring allows for thermal expansion of the recuperator and turbine support adapter while alleviating any stress or fatigue damage to the adapter. Each of the outer strutted bodies further comprises an outer ring and an inner ring connected by a plurality of struts. The recuperator and turbine support adapter also provides a means of directing the flow of cold compressed air to the recuperator and the return of the recuperator heated air to the combustor/turbine module.

Abstract: A silicon wafer is provided which does not employ individually bonded leads between the IR sensitive elements and the input stages of multiplexers. The wafer is first coated with lead selenide in a first detector array area and is thereafter coated with lead sulfide within a second detector array area. The described steps result in the direct chemical deposition of lead selenide and lead sulfide upon the silicon wafer to eliminate individual wire bonding, bumping, flip chiping, planar interconnecting methods of connecting detector array elements to silicon chip circuitry, e.g., multiplexers, to enable easy fabrication of very long arrays. The electrode structure employed, produces an increase in the electrical field gradient between the electrodes for a given volume of detector material, relative to conventional electrode configurations.

Abstract: Heat recovery systems are useful, for example, in vehicles that generate large amounts of heat energy during operation. The heat energy is used to drive a dual pressure turbine for producing useful work. In order to fully utilize the great majority of the heat energy produced, the engine exhaust is used to convert a fluid to a gas and superheat the gas to a preselected temperature at a preselected pressure. A first stage of the dual pressure turbine receives the superheated gas and directs the gas at a supersonic velocity against the blades of the rotor. The gas exiting the first stage and the superheated gas at a lower preselected temperature is controllably and substantially separately directed to a second stage at substantially the same velocity. This heat recovery system fully utilizes the heat energy generated by the engine and substantially eliminates the sooting and the formation of oxides within the exhaust system.

Abstract: An infrared photodetector is disclosed which is deposited directly onto a Joule-Thomson cryostat. The cryostat includes an elongated body having gas-carrying channels contained therein. The photodetector is deposited directly onto one end of the elongated body to form a direct thermal path between the detector and cryostat, thereby eliminating the need for any intermediate thermal bridge such as a mechanical bond, thermal conductive paste or epoxy. The direct contact between the photodetector material and the cryostat reduces the thermal mass of the structure to be cooled by the cryostat, thereby decreasing both the time and the quantity of gas required to cool the detector.

Abstract: A silicon wafer is provided which does not employ individually bonded leads between the IR sensitive elements and the input stages of multiplexers. The wafer is first coated with lead selenide in a first detector array area and is thereafter coated with lead sulfide within a second detector array area. The described steps result in the direct chemical deposition of lead selenide and lead sulfide upon the silicon wafer to eliminate individual wire bonding, bumping, flip chipping, planar interconnecting methods of connecting detector array elements to silicon chip circuitry, e.g., multiplexers, to enable easy fabrication of very long arrays. The electrode structure employed, produces an increase in the electrical field gradient between the electrodes for a given volume of detector material, relative to conventional electrode configurations.

Abstract: Heat recovery systems are useful, for example, in vehicles that generate large amounts of heat energy during operation. The heat energy is used to drive a turbine that produces useful work. In order to fully utilize the great majority of the heat energy produced, the engine exhaust is used to convert a fluid to a gas and superheat the gas to a preselected temperature at a preselected pressure. If the fluid entering the heat exchanger in the exhaust system is to cool, soot collects on the heat exchanger thus greatly reducing system efficiency. Also various oxides precipitate out of the exhaust and chemical attack the elements in the exhaust system. The present heat recovery system utilizes the heat energy from the oil cooling system to preheat all of the fluid before it reaches the exhaust system. Furthermore, the heat energy from the jacket water of the engine is used to convert a portion of the preheated fluid to a gas.