Abstract: In an aircraft including a gas turbine engine having a compressor including a compressor booster, a turbine, and a nacelle, a system for cooling compressor discharge air provided to the turbine to cool the turbine includes a heat exchanger provided in a nacelle compartment of the gas turbine engine configured to cool the compressor discharge air by exchanging heat from the compressor discharge air to a cooling fluid; and a cooling fluid circuit configured to circulate cooling fluid through the heat exchanger and a heat sink, wherein the heat sink is at least one of an inlet of the nacelle compartment, an inlet of the compressor booster, or outlet guide vanes of the gas turbine engine.

Abstract: Optically patterned waveguides and systems employing optically pattered waveguides are provided. The optically patterned waveguide is configured for use in a lighting system and arranged perpendicular to an overhead structure, such as a ceiling. The optically patterned waveguide includes major surfaces that are patterned with a plurality of elongated facets formed into the major surfaces and extending in a direction parallel to the length of the waveguide. The optically patterned waveguide provides illumination patterns having increased uniformity.

Abstract: Approaches are disclosed for electrical impedance tomography which apply a current to a region at two or more frequencies and acquire voltage measurements at each frequency to generate a set of multi-frequency voltage measurements. One or more images of the region are generated, using spectral constraints, based on the multi-frequency data.

Abstract: A combustion dynamics control system for an aviation based or land based gas turbine engine employs an acoustic driver that is configured to drive pressure perturbations across a premixed fuel injection orifice to substantially zero in response to a control signal such that fuel flow perturbations across the fuel injection orifice are substantially zero.

Abstract: A combustor structure includes a combustor fuel-air mixing apparatus having a mainstream airflow region. One or more concavities are disposed within the mainstream airflow region of the fuel-air mixing apparatus. At least one fuel injection hole is disposed within an upstream base region of at least one concavity. Passing a stream of air through the main airflow region causes fuel injected into the upstream base region of at least one concavity to passively mix with a naturally oscillating vortex of air within the concavity.

Abstract: A stator assembly includes a segmented stator having stator portions. Each stator portion includes a support structure and dovetails, each coupled to the support structure by adjustable elements. The stator portion also includes stator laminations, where each of the laminations has openings to engage with the dovetails. Connectors are provided to connect the stator portions of the segmented stator together.

Abstract: A fluid dynamic structure includes a surface and a microstructure mounted on the surface. The microstructure is defined by a plurality of peaks and valleys (i.e., riblets) and includes a transition region in which each peak and valley changes from a first profile to a second profile along a chord length of the structure. The peaks and/or valleys may have a variable dimension along the length of the microstructure. The peaks and valleys can be non-linear along the chord length and have a smooth transition from the first profile to the second profile. The different profiles of the microstructure are optimized to reduce noise generated by turbulent fluid flow across the structure.

Abstract: A method for manufacturing an article for use in a high-temperature environment, and an article for use in such an environment, are presented. The method comprises providing a substrate; selecting a desired vertical crack density for a protective coating to be deposited on the substrate; providing a powder, wherein the powder has a size range selected to provide a coating having the desired vertical crack density; and applying a thermal-sprayed coating to the substrate, the coating having the desired vertical crack density, wherein the powder is used as a raw material for the coating.

Abstract: A fuel cell assembly comprises at least one fuel cell. The fuel cell comprises an anode and a cathode held in a spaced apart relationship by at least one spacer element comprising an electrically insulating material. A proximal end of the spacer element is in contact with the cathode, and a distal end is in contact with the anode. An electrolyte is disposed between, and in contact with the anode and the cathode. The electrolyte comprises a molten salt having a hydride ion conductance number greater than about 0.95 at a fuel cell operating temperature. A fuel gas inlet, adjacent to the cathode, is provided for delivering a fuel gas to the electrolyte. An oxidizing gas inlet, adjacent to the anode, is provided for delivering an oxidizing gas to the electrolyte. An exhaust port is in fluid communication with the anode.

Abstract: In one embodiment of the present invention, an apparatus for detecting a hot rail car surface comprises: an infrared sensor for acquiring an infrared signal from a rail car surface of a rail car and transducing the infrared signal into an electrical signal; a rank filter for filtering the electrical signal to produce a filtered array; a first peak detector for detecting a maximum filtered value of the filtered array; and a first comparator for comparing the maximum filtered value to a detection threshold to produce a filtered alarm signal.