Abstract: A circuit can include a closed loop bus line having a plurality of connections. The circuit can include a plurality of integrated circuits disposed on the close loop bus line at a respective connection of the plurality of connections. One or more of the integrated circuits can be configured to drive a signal on the closed loop bus line. The closed loop bus line can be configured to prevent signal reflection. For example, in certain embodiments, there are no termination resistors at any of the terminations to reduce size, weight, and/or part count of the circuit.

Abstract: In accordance with at least one aspect of this disclosure, a power system for a vehicle is disclosed. The system can include, one or more power distribution sources configured to supply electrical power to one or more power districts. One or more power conversion devices can be housed within a respective power district. In embodiments, the power district can be configured to allow for managing a draw by a respective one or more loads within the respective power district. The one or more power conversion devices can be configured to receive electrical power from one or more of the one or more power distribution sources, convert the electrical power to a secondary form, and then the converted electrical power to the one or more loads within the respective power district. In embodiments, a logic module can be operatively connected to the one or more power districts, configured to control at least a load draw.

Abstract: A power system includes a field effect transistor (FET) with a first terminal, a gate terminal, and a third terminal. A Zener diode is connected in series between the first terminal of the FET and the gate terminal of the FET. The Zener diode is oriented to allow current through the Zener diode only if its voltage difference is at or over the Zener voltage of the Zener diode. A capacitor is connected in parallel with the Zener diode. The capacitor is configured to raise gate drive current of the FET during a rising edge of a lightning transient and thereby reduce voltage drop across the FET faster than the Zener diode can do on its own.

Abstract: In accordance with at least one aspect of this disclosure, a method of making a carbon rotor includes, providing a quantity of material, densifying the quantity of material, and forming the densified material into a disk shape.

Abstract: Disclosed is a cabin air compressor (CAC) of an aircraft environmental control system, the CAC having: a CAC case defining a forward end and an aft end axially spaced apart axially from the forward end, wherein the forward end defines a compressor inlet; and a supplemental cooling passage defined by the CAC case, wherein the supplemental cooling passage is configured to direct a supplemental cooling medium through it.

Abstract: An integrally bladed rotor includes a rotor disk, rotor blade, internal channel and air outlets. The rotor blade includes a body defined by a pressure surface and suction surface between a leading edge and a trailing edge. The internal channel extends radially from the rotor disk internally within the body of the rotor blade. The air outlets are formed proximate the leading edge and extend within the body of the rotor blade to the internal channel.

Abstract: A gear pump includes gears received within a housing defining an inlet, an outlet and end plates. The gears have shaft portions on each of two sides of each of the two gears. The shaft portions are mounted in journal bearings. The journal bearings each have a gear side face adjacent one of the two gears. A remote face is on a remote side of the journal bearing remote from each of the two gears. There is a plurality of heat pipes in at least one of the journal bearings. The heat pipes move heat from the gear face of the at least one of the journal bearings to the remote face. The plurality of heat pipes is enclosed by the housing, and extend generally in an axial direction from an end adjacent the gear face to an end adjacent the remote face. A fuel supply system is also disclosed.

Abstract: A layer of a heat exchanger includes plurality of flow paths, a first end section comprising a plurality of flow path inlets and a plurality flow path outlets. a second end section comprising a turnaround section, a first morphing section fluidly connect to the first end section, a second morphing section fluidly connected to the second end section; and a central section positioned between and fluidly connected to the first and second morphing sections. The plurality of flow paths extend from the flow path inlets to the flow path outlets via the turnaround section in the second end section. In the first end section and the second end section the flow paths have a first cross section. The central section the flow paths have a second cross section and in the first and second morphing section the cross section of the flow paths morph between first and second cross sections.

Abstract: A fuel system of an aircraft engine, having: a boost pump having an input and an output; one or more selector valves; a first component pump having an input fluidly coupled to the output of the boost pump and an output of the first component pump is configured to direct fuel to a first component via the one or more selector valves; and a second component pump having an input that is selectively coupled to either the input or the output of the boost pump by the one or more selector valves, and an output of the second component pump is fluidly coupled to a second component and selectively coupled to the first component by the one or more selector valves.

Abstract: Systems for a current limiting circuit are provided. Aspects include a first set of batteries coupled to a battery terminal, a power converter coupled to a power converter terminal, wherein the battery terminal is coupled to the power converter terminal, a first current limiting circuit in series with the first set of batteries, wherein the current limiting circuit comprises a first circuit comprising a first transistor in series with a first diode, a second circuit comprising a second transistor in series with a second diode, a first RL circuit, wherein the first RL circuit, the first circuit, and the second circuit are arranged in parallel, a controller configured to operate the first current limiter in a plurality of modes including a battery discharge mode including the controller operating the first transistor in an off state, and operating the second transistor in a switching state.

Abstract: A control system for an electric motor powered by a battery can be configured to receive an input instantaneous power or torque command corresponding to a commanded instantaneous power or torque. The control system can be configured to determine if the battery is capable of supplying the commanded instantaneous power or torque based on a state of charge (SOC) of the battery. The control system can be configured such that if the battery is capable of supplying the commanded instantaneous power or torque, the control system outputs the input instantaneous power or torque command, and such that if the battery is not capable of supplying the commanded instantaneous power or torque, the control system outputs an available maximum instantaneous power or torque command corresponding to an available maximum instantaneous power or torque that is less than the commanded instantaneous power or torque.

Abstract: In accordance with at least one aspect of this disclosure, a system includes one or more collection units configured to collect a sample from an aerosol cloud and a detection unit configured to analyze a composition the sample from the aerosol cloud. In certain embodiments, the one or more collection units can include a plurality of collection units. In embodiments, the collection unit can include a collection medium configured to collect aerosol particles from the aerosol cloud and condense or trap the aerosol particles on or in the collection medium.

Abstract: A method of providing a protective titanium layer to an outer surface of an aluminum component includes providing an aluminum component and forming a first layer of titanium-based bulk metallic glass on the component, wherein formation of the bulk metallic glass layer comprises depositing a titanium alloy powder using pulsed directed energy deposition.

Abstract: A rotor for a rotary machine includes a hub centered on a central axis, the hub comprising a shaft portion extending along the central axis, a disk portion circumferentially disposed about the shaft portion, a platform portion as a radially outermost extent of the shaft portion and the disk portion, and a branched support structure extending radially inward from the platform portion. The rotor further includes a plurality of blades extending outward from the platform portion of the hub. The branched support structure comprises a hub region and a blade support region associated with one blade of the plurality of blades.

Abstract: An assembly comprises an AC (alternating current) housing connection block and a plurality of inserts seated in the AC housing connection block, wherein for each of the inserts, an interface between the insert and the housing is continuous. A method includes inserting a plurality of inserts into a mold; and molding an AC (alternating current) housing connection block.

Abstract: A polymer-matrix fiber-reinforced composite structure includes a plurality of polymer composite layers having at least one polymer composite layer that includes a first polymer-matrix and a first fluorescent agent interspersed through the first polymer-matrix. Damage to the polymer composite structure results in a change in fluorescence at the point of damage. A method for detecting damage in the polymer composite structure described above including the steps of applying light having a wavelength selected to induce fluorescence in the first fluorescent agent to the polymer composite structure, detecting a detected fluorescence pattern, and comparing the detected fluorescence pattern to a predetermined normal fluorescence pattern.

Abstract: A composite/metal joint includes a composite member, a metallic member, a cylindrical liner, and a fastener. The composite member has a first aperture. The metallic member is disposed adjacent to the composite member and has a second aperture coaxially aligned with the first aperture. The cylindrical liner extends longitudinally from a first end to a second end. The cylindrical liner has a cylindrical outer liner surface and a longitudinally extending third aperture coaxial with the first and second apertures and defined by an inner liner surface. The cylindrical liner is disposed in the first and second apertures with the outer liner surface adjacent to aperture walls of the first and second apertures. The cylindrical liner has a plurality of grooves intersecting the outer liner surface. The fastener is disposed through the third aperture of the cylindrical liner and is configured to attach the metallic member to the composite member.

Abstract: Thermal management techniques include: transporting a refrigerant fluid from a receiver to an inlet of a flash tank that has a vapor-side outlet and liquid-side outlet such that a liquid phase of the refrigerant fluid moves to a bottom of the flash tank and outputs from the liquid-side outlet; forming a solid-vapor state from the liquid phase by expanding the liquid phase with an expansion valve to a first pressure that is less than a triple point pressure to form a solid-vapor mixture of the refrigerant fluid; extracting heat from a heat load with an evaporator that receives the solid-vapor mixture of the refrigerant fluid and sublimates the solid state of the solid-vapor mixture of the refrigerant fluid directly into a vapor phase of the refrigerant fluid; and discharging, from an exhaust line, the vapor phase to an ambient environment without returning the vapor phase to the receiver.

Abstract: A variable channel diffuser includes a shroud, a backing plate, a channel plate adjacent to the backing plate, a floor plate adjacent to the shroud, standoffs formed on the floor plate, and recessed areas formed in the channel plate. The channel plate is between the shroud and the backing plate. The floor plate is between the shroud and the channel plate and is movable relative to the channel plate. The standoffs and the recessed areas define channels for fluid flow. Each channel has an area which is variable through movement of the floor plate relative to the channel plate.

Abstract: In accordance with at least one aspect of this disclosure, a method can include measuring a voltage across a DC link of a generator system when a generator exciter is inactive and a generator permanent magnet is active, and detecting a short or open permanent magnet generator (SOPMG) fault condition in the generator system with a DC link monitor operatively connected to measure the voltage across the DC link.