Abstract: A carbon-carbon composite preform including a plurality of layers including carbon fibers or carbon-precursor fibers, the layers include a first exterior layer defining a first major surface, a second exterior layer defining a second major surface, and at least one interior layer disposed between the first exterior layer and the second exterior layer, the at least one interior layer having a peripheral region that forms a portion of an outer surface of the preform. The preform includes needled fibers, where at least some needled fibers extend through two or more layers. The preform has an exterior region and a core region, where the exterior region includes at least the peripheral region of at least one interior layer. The needled fibers define a first needled fiber number density (NFND) in the exterior region and a second greater NFND in at least a portion of the core region.

Abstract: An Environmental Control System includes sensors, an air purification subsystem, and a controller in communication with the sensors and air purification subsystem. The sensors detect contaminants in outside air supplied through engine and APU bleeds or other air sources including ground supplies and electric compressors, contaminants in recirculated air, particulates in outside air, carbon dioxide in recirculated air, temperature in an environment, and pressure in an environment. These sensed parameters are compared against thresholds. Based on the comparisons, changes to the outside air and/or recirculated air are made.

Abstract: An Environmental Control System includes a sensor, an air purification subsystem, and a controller in communication with the sensor and air purification subsystem. The sensor detects a contaminant in the air and generates a contaminant signal. The controller compares the contaminant signal to a predicted sensory response threshold. When the contaminant signal reaches the predicted sensory response threshold, the controller commands the air purification subsystem to alter a condition in the air.

Abstract: An Environmental Control System includes a sensor, an air purification subsystem, and a controller in communication with the sensor and air purification subsystem. The sensor detects a contaminant in the air and generates a contaminant signal. The controller compares the contaminant signal to a predicted sensory response threshold. When the contaminant signal reaches the predicted sensory response threshold, the controller commands the air purification subsystem to alter a condition in the air.

Abstract: An Environmental Control System includes a sensor, an air purification subsystem, and a controller in communication with the sensor and air purification subsystem. The sensor detects a contaminant in the air and generates a contaminant signal. The controller compares the contaminant signal to a predicted sensory response threshold. When the contaminant signal reaches the predicted sensory response threshold, the controller commands the air purification subsystem to alter a condition in the air.

Abstract: An Environmental Control System includes a sensor, an air purification subsystem, and a controller in communication with the sensor and air purification subsystem. The sensor detects a contaminant in the air and generates a contaminant signal. The controller compares the contaminant signal to a predicted sensory response threshold. When the contaminant signal reaches the predicted sensory response threshold, the controller commands the air purification subsystem to alter a condition in the air.

Abstract: An Environmental Control System includes a sensor, an air purification subsystem, and a controller in communication with the sensor and air purification subsystem. The sensor detects a contaminant in the air and generates a contaminant signal. The controller compares the contaminant signal to a predicted sensory response threshold. When the contaminant signal reaches the predicted sensory response threshold, the controller commands the air purification subsystem to alter a condition in the air.

Abstract: A carbon-carbon composite preform including a plurality of layers including carbon fibers or carbon-precursor fibers, the layers include a first exterior layer defining a first major surface, a second exterior layer defining a second major surface, and at least one interior layer disposed between the first exterior layer and the second exterior layer, the at least one interior layer having a peripheral region that forms a portion of an outer surface of the preform. The preform includes needled fibers, where at least some needled fibers extend through two or more layers. The preform has an exterior region and a core region, where the exterior region includes at least the peripheral region of at least one interior layer. The needled fibers define a first needled fiber number density (NFND) in the exterior region and a second greater NFND in at least a portion of the core region.

Abstract: A system is provided for inerting a fuel tank of an aircraft. The system includes a first compressor fluidly coupled to the fuel tank for removing an air and fuel vapor mixture from an ullage of the fuel tank. The system further includes a fuel processor fluidly coupled to the first compressor and configured to receive the air and fuel vapor mixture and to generate hydrogen from the air and fuel vapor mixture. The system further includes a fuel cell fluidly coupled to the fuel processor and configured to receive the hydrogen as anode fuel to produce electricity. The system further includes a combustor fluidly coupled to the fuel cell and configured to combust the exhaust product to produce combustion gas, and a first heat exchanger fluidly coupled to the combustor and configured to cool the combustion gas into inerting gas for the fuel tank.

Abstract: An aircraft fuel deoxygenation and tank inerting system includes an inert gas source, a fuel deoxygenation system, and an air/fuel heat exchanger. The inert gas source is configured to supply inert gas having an oxygen concentration of less than 3%. The fuel deoxygenation system is adapted to receive fuel from a fuel source and the inert gas from the inert gas source. The fuel deoxygenation system is configured to remove oxygen from the fuel and thereby generate and supply deoxygenated fuel and oxygen-rich purge gas. The air/fuel heat exchanger is adapted to receive compressed air from a compressed air source and the deoxygenated fuel from the fuel deoxygenation system. The air/fuel heat exchanger is configured to transfer heat from the compressed air to the deoxygenated fuel, to thereby supply cooled compressed air and heated deoxygenated fuel.

Abstract: A system is provided for inerting a fuel tank of an aircraft. The system includes a first compressor fluidly coupled to the fuel tank for removing an air and fuel vapor mixture from an ullage of the fuel tank. The system further includes a fuel processor fluidly coupled to the first compressor and configured to receive the air and fuel vapor mixture and to generate hydrogen from the air and fuel vapor mixture. The system further includes a fuel cell fluidly coupled to the fuel processor and configured to receive the hydrogen as anode fuel to produce electricity. The system further includes a combustor fluidly coupled to the fuel cell and configured to combust the exhaust product to produce combustion gas, and a first heat exchanger fluidly coupled to the combustor and configured to cool the combustion gas into inerting gas for the fuel tank.

Abstract: An air purification system includes a photocatalyst on a support disposed to contact airflow through an airflow channel passing across or through the support; an ultraviolet light emitting diode (UV-LED) disposed to emit ultraviolet light onto the photocatalyst, the UV-LED operated at a less than one hundred percent duty cycle, the duty cycle determined at least in part as a function of a desired minimum volatile organic compound conversion rate of air flowing through the airflow channel and a desired maximum by-product concentration of air flowing through an outlet of the airflow channel.

Abstract: A system is provided for inerting a fuel tank of an aircraft. The system includes a first compressor fluidly coupled to the fuel tank for removing an air and fuel vapor mixture from an ullage of the fuel tank. The system further includes a fuel processor fluidly coupled to the first compressor and configured to receive the air and fuel vapor mixture and to generate hydrogen from the air and fuel vapor mixture. The system further includes a fuel cell fluidly coupled to the fuel processor and configured to receive the hydrogen as anode fuel to produce electricity. The system further includes a combustor fluidly coupled to the fuel cell and configured to combust the exhaust product to produce combustion gas, and a first heat exchanger fluidly coupled to the combustor and configured to cool the combustion gas into inerting gas for the fuel tank.

Abstract: An Environmental Control System includes sensors, an air purification subsystem, and a controller in communication with the sensors and air purification subsystem. The sensors detect contaminants in outside air supplied through engine and APU bleeds or other air sources including ground supplies and electric compressors, contaminants in recirculated air, particulates in outside air, carbon dioxide in recirculated air, temperature in an environment, and pressure in an environment. These sensed parameters are compared against thresholds. Based on the comparisons, changes to the outside air and/or recirculated air are made.

Abstract: An Environmental Control System includes a sensor, an air purification subsystem, and a controller in communication with the sensor and air purification subsystem. The sensor detects a contaminant in the air and generates a contaminant signal. The controller compares the contaminant signal to a predicted sensory response threshold. When the contaminant signal reaches the predicted sensory response threshold, the controller commands the air purification subsystem to alter a condition in the air.

Abstract: An air purification system includes a photocatalyst on a support disposed to contact airflow through an airflow channel passing across or through the support; an ultraviolet light emitting diode (UV-LED) disposed to emit ultraviolet light onto the photocatalyst, the UV-LED operated at a less than one hundred percent duty cycle, the duty cycle determined at least in part as a function of a desired minimum volatile organic compound conversion rate of air flowing through the airflow channel and a desired maximum by-product concentration of air flowing through an outlet of the airflow channel.

Abstract: A system is provided for inerting a fuel tank of an aircraft. The system includes a first compressor fluidly coupled to the fuel tank for removing an air and fuel vapor mixture from an ullage of the fuel tank. The system further includes a fuel processor fluidly coupled to the first compressor and configured to receive the air and fuel vapor mixture and to generate hydrogen from the air and fuel vapor mixture. The system further includes a fuel cell fluidly coupled to the fuel processor and configured to receive the hydrogen as anode fuel to produce electricity. The system further includes a combustor fluidly coupled to the fuel cell and configured to combust the exhaust product to produce combustion gas, and a first heat exchanger fluidly coupled to the combustor and configured to cool the combustion gas into inerting gas for the fuel tank.

Abstract: An aircraft fuel deoxygenation and tank inerting system includes an inert gas source, a fuel deoxygenation system, and an air/fuel heat exchanger. The inert gas source is configured to supply inert gas having an oxygen concentration of less than 3%. The fuel deoxygenation system is adapted to receive fuel from a fuel source and the inert gas from the inert gas source. The fuel deoxygenation system is configured to remove oxygen from the fuel and thereby generate and supply deoxygenated fuel and oxygen-rich purge gas. The air/fuel heat exchanger is adapted to receive compressed air from a compressed air source and the deoxygenated fuel from the fuel deoxygenation system. The air/fuel heat exchanger is configured to transfer heat from the compressed air to the deoxygenated fuel, to thereby supply cooled compressed air and heated deoxygenated fuel.

Abstract: Apparatus and methods for the production of a secure supply of breathable air are important under conditions where threats from chemical and biological weapons may be present. A method and a multi-stage CATOX system for producing a purified air flow from ambient air which may have nitrogen containing toxicants is provided. The multi-stage CATOX system has a first stage and second stage, at least one of the first or the second stage has a first catalytic heat exchanger with a cold side supporting a first catalyst and a hot side configured to transfer heat therefrom to the first catalyst.