Abstract: Disclosed herein are circular RNAs and transfer vehicles, along with related compositions and methods of treatment. The circular RNAs can comprise group I intron fragments, spacers, an IRES, duplex forming regions, and/or an expression sequence, thereby having the features of improved expression, functional stability, low immunogenicity, ease of manufacturing, and/or extended half-life compared to linear RNA. Pharmaceutical compositions comprising such circular RNAs and transfer vehicles are particularly suitable for efficient protein expression in immune cells in vivo. Also disclosed are precursor RNAs and materials useful in producing the precursor or circular RNAs, which have improved circularization efficiency and/or are compatible with effective circular RNA purification methods.

Abstract: An iron-air battery including an iron electrode in contact with an anode current collector, wherein the iron electrode includes a plurality of channels; an oxygen reduction reaction electrode having a first surface facing the plurality of channels and an opposing second surface in contact with air; an oxygen evolution reaction electrode interdigitated with the plurality of channels of the iron electrode, wherein at least a portion of the oxygen evolution reaction electrode is disposed within the plurality of channels in a direction perpendicular to a plane of the oxygen reduction reaction electrode; and an electrolyte in contact with the iron electrode, the first surface of the oxygen reduction reaction electrode, the plurality of channels, and the oxygen evolution reaction electrode.

Abstract: A system may comprise a sensor configured to measure a characteristic of an engine component. A valve assembly may have an airflow outlet in fluid communication with the engine component. The valve assembly may include a first valve. A first valve control device may be coupled to the first valve and configured to control the first valve based on a measurement by the sensor. A second valve may be in fluidic series with the first valve. A second valve control device may be coupled to the second valve and configured to control the second valve based on the measurement by the sensor.

Abstract: A system may comprise a sensor configured to measure a characteristic of an engine component. A valve assembly may have an airflow outlet in fluid communication with the engine component. The valve assembly may include a first valve. A first valve control device may be coupled to the first valve and configured to control the first valve based on a measurement by the sensor. A second valve may be in fluidic series with the first valve. A second valve control device may be coupled to the second valve and configured to control the second valve based on the measurement by the sensor.

Abstract: A system may comprise a sensor configured to measure a characteristic of an engine component. A valve assembly may have an airflow outlet in fluid communication with the engine component. The valve assembly may include a first valve. A first valve control device may be coupled to the first valve and configured to control the first valve based on a measurement by the sensor. A second valve may be in fluidic series with the first valve. A second valve control device may be coupled to the second valve and configured to control the second valve based on the measurement by the sensor.

Abstract: An anti-icing system of a nacelle inlet of an engine of an aircraft includes first and second direct acting valves and first and second control valve assemblies fluidly connected to the nacelle inlet. The first direct acting valve includes a first inlet, outlet, valve chamber, and piston. The first piston is positioned in the first direct acting valve. The first control valve assembly is fluidly connected to the first valve. The second direct acting valve includes a second inlet, outlet, valve chamber, and piston. The second piston is positioned in the second direct acting valve. The second direct acting valve is fluidly connected to the first direct acting valve in a series configuration. The second control valve assembly is fluidly connected to the second valve chamber.

Abstract: A system may comprise a sensor configured to measure a characteristic of an engine component. A valve assembly may have an airflow outlet in fluid communication with the engine component. The valve assembly may include a first valve. A first valve control device may be coupled to the first valve and configured to control the first valve based on a measurement by the sensor. A second valve may be in fluidic series with the first valve. A second valve control device may be coupled to the second valve and configured to control the second valve based on the measurement by the sensor.

Abstract: An anti-ice system includes a duct that extends from a hot air bleed source to an anti-ice manifold and a direct-acting valve coupled to the duct. The duct may be configured to route hot air from the hot air bleed source to the anti-ice manifold at a regulated pressure and the direct-acting valve may include an inlet portion, a reference chamber, a force-type torque motor, an outlet portion, and a modulating sleeve. The inlet portion may be configured to be in hot air receiving communication with hot air from the hot air bleed source, the reference chamber may be configured to be in hot air receiving communication with the inlet portion, the force-type torque motor may be configured to control a reference pressure of hot air in the reference chamber, and the outlet portion may be configured in hot air receiving communication with the inlet portion via the modulating sleeve.

Abstract: A system may comprise a sensor configured to measure a characteristic of an engine component. A valve assembly may have an airflow outlet in fluid communication with the engine component. The valve assembly may include a first valve. A first valve control device may be coupled to the first valve and configured to control the first valve based on a measurement by the sensor. A second valve may be in fluidic series with the first valve. A second valve control device may be coupled to the second valve and configured to control the second valve based on the measurement by the sensor.

Abstract: A system is provided comprising: a starter air valve in fluid communication with an air turbine starter to drive motoring of a gas turbine engine responsive to a compressed air flow from a compressed air source; a manual override operably connected to the starter air valve, the manual override is operable to open the starter air valve a select percentage by moving the manual override to a detent engaged position, wherein the select percentage is operable to allow enough airflow to achieve the maximum allowed motoring speed of the gas turbine engine; and a pressure regulating bleed valve in fluid communication with the starter air valve, the pressure regulating bleed valve operable to bleed a portion of the compressed air flow to regulate a motoring speed of the gas turbine engine in response to detection of the manual override in a detent engaged position.

Abstract: According to an aspect, a system includes a starter air valve in fluid communication with an air turbine starter to drive motoring of a gas turbine engine responsive to a compressed air flow from a compressed air source. The system also includes a variable-position electromechanical device operable to adjust positioning of the starter air valve and a discrete-position electromechanical device operable to adjust positioning of the starter air valve and limit a motoring speed of the gas turbine engine below a resonance speed of the gas turbine engine responsive to a pulse width modulation control based on a failure of the variable-position electromechanical device.

Abstract: An anti-icing system of a nacelle inlet of an engine of an aircraft includes first and second direct acting valves and first and second control valve assemblies fluidly connected to the nacelle inlet. The first direct acting valve includes a first inlet, outlet, valve chamber, and piston. The first piston is positioned in the first direct acting valve. The first control valve assembly is fluidly connected to the first valve. The second direct acting valve includes a second inlet, outlet, valve chamber, and piston. The second piston is positioned in the second direct acting valve. The second direct acting valve is fluidly connected to the first direct acting valve in a series configuration. The second control valve assembly is fluidly connected to the second valve chamber.

Abstract: A starter air valve comprising: a housing comprising an inlet at a first end, an outlet at a second end opposite the first end, and a center portion between first end and second end, the outlet being fluidly connected to the inlet through a fluid passage; a first piston located within the housing between the first end and center portion, the first piston comprising: a first cupped portion configured to form a first chamber with the housing proximate the first end; and a second piston located within the housing between the second end and center portion, the second piston comprising: a third cupped portion configured to form a third chamber with the housing proximate the second end; wherein the pistons are configured to regulate airflow through the fluid passage by adjusting at least one of a first pressure within the first chamber and a third pressure within the third chamber.

Abstract: A starter air valve comprising: a housing comprising an inlet at a first end, an outlet at a second end opposite the first end, and a center portion between the first and second end, the outlet being fluidly connected to the inlet through a fluid passage; a first piston located within the housing between first end and center portion, the first piston configured to block airflow through the fluid passage when in a closed position and allow airflow through the fluid passage when in an open position; a second piston located within the housing between second end and center portion, the second piston configured to block airflow through the fluid passage when in a closed position and allow airflow through the fluid passage when in an open position; and a manual override system configured to move from closed to open position at least one of the first and second pistons.

Abstract: An anti-icing system of a nacelle inlet of an engine of an aircraft includes first and second direct acting valves and first and second control valve assemblies fluidly connected to the nacelle inlet. The first direct acting valve includes a first inlet, outlet, valve chamber, and piston. The first piston is positioned in the first direct acting valve. The first control valve assembly is fluidly connected to the first valve. The second direct acting valve includes a second inlet, outlet, valve chamber, and piston. The second piston is positioned in the second direct acting valve. The second direct acting valve is fluidly connected to the first direct acting valve in a series configuration. The second control valve assembly is fluidly connected to the second valve chamber.

Abstract: A valve includes an inlet, an outlet, and a biasing element. The biasing element includes a first spring element, a second spring element, and a valve element. The second spring element includes at least one bimetallic disk including a first and second material. The first material includes a first coefficient of linear thermal expansion, and the second material includes a second coefficient of linear thermal expansion different than the first coefficient of linear thermal expansion. The valve element disposed on an end of the first spring element.

Abstract: A bleed valve includes a valve body, a first flapper body movable relative to the valve body between an open position and a closed position, and a second flapper body movable relative to the valve body between an open position and a closed position. A resilient member biases the first and second flapper bodies to the open position to vent bleed air. The first and second flapper bodies move to the closed position when a pressure load across the first and second flapper bodies exceeds a biasing force of the resilient member. A gas turbine engine is also disclosed.

Abstract: A system may comprise a sensor configured to measure a characteristic of an engine component. A valve assembly may have an airflow outlet in fluid communication with the engine component. The valve assembly may include a first valve. A first valve control device may be coupled to the first valve and configured to control the first valve based on a measurement by the sensor. A second valve may be in fluidic series with the first valve. A second valve control device may be coupled to the second valve and configured to control the second valve based on the measurement by the sensor.

Abstract: According to an aspect, a system includes a starter air valve in fluid communication with an air turbine starter to drive motoring of a gas turbine engine responsive to a compressed air flow from a compressed air source. The system also includes a variable-position electromechanical device operable to adjust positioning of the starter air valve and a discrete-position electromechanical device operable to adjust positioning of the starter air valve and limit a motoring speed of the gas turbine engine below a resonance speed of the gas turbine engine responsive to a pulse width modulation control based on a failure of the variable-position electromechanical device.

Abstract: A system is provided comprising: a starter air valve in fluid communication with an air turbine starter to drive motoring of a gas turbine engine responsive to a compressed air flow from a compressed air source; a manual override operably connected to the starter air valve, the manual override is operable to open the starter air valve a select percentage by moving the manual override to a detent engaged position, wherein the select percentage is operable to allow enough airflow to achieve the maximum allowed motoring speed of the gas turbine engine; and a pressure regulating bleed valve in fluid communication with the starter air valve, the pressure regulating bleed valve operable to bleed a portion of the compressed air flow to regulate a motoring speed of the gas turbine engine in response to detection of the manual override in a detent engaged position.