A system has: a combustor; a plenum surrounding the combustor; a transfer tube having an inlet fluidly connected to the plenum and at least two outlets, a first flow passageway defined between the inlet and a first outlet, a second flow passageway defined between the inlet and a second outlet, the second flow passageway connected to a discharge region outside of the plenum; a flow valve disposed within the second flow passageway and operable between an open position and a closed position, in the open position the flow valve fluidly connects the plenum with the discharge region, in the closed position the flow valve blocking fluid communication between the plenum and the discharge region; and a controller communicatively coupled to the flow valve to control operation thereof by: causing the flow valve to open for a time period; and subsequent to the time period, causing the flow valve to close.

A method for controlling noise emitted by a hybrid-electric gas turbine engine for an aircraft during a takeoff flight condition includes applying a first total rotational force to a shaft with a turbine and an electric motor. The first total rotational force includes a first electric rotational force applied by the electric motor and a first thermal rotational force applied by the turbine. The first total rotational force has a first rotational force ratio of the first electric rotational force to the first thermal rotational force. The method further includes controlling the noise emitted by the gas turbine engine by reducing the first rotational force ratio from an initial rotational force ratio of the rotational force ratio as an altitude of the aircraft increases and maintaining the first total rotational force substantially constant while reducing the rotational force ratio.

Hybrid electric propulsion systems are described. The systems include a gas turbine engine having a low speed spool and a high speed spool. The low speed spool includes a low pressure compressor and a low pressure turbine and the high speed spool includes a high pressure compressor and a high pressure turbine. An electric machine is configured to augment rotational power of at least one of the high speed spool and the low speed spool. A controller is configured to control the electric machine to one of add or subtract rotational energy to or from at least one of the high speed spool and the low speed spool during a transition to or from an idle state of operation of the gas turbine engine.

Devices and methods for the efficient disaggregation of tissue samples, separating the tissue into individual intact cells or small aggregates of cells for analysis. A device may include a chamber to receive fluid and a tissue specimen containing more than one cell to be disaggregated. The chamber may include an opening and an agitator in fluid contact with the fluid and the tissue specimen. The agitator may include a micromotor which provides rotational motion to a shaft and an impeller fixed to the shaft such that the impeller and the shaft rotate together upon provision of the rotational motion by the micromotor. The device may include an electrical energy source electrically coupled to the micromotor to rotate the impeller sufficient to disaggregate the one or more individual cells from the tissue specimen and in a manner which does not lyse the one or more individual cells.

Systems and methods for adjusting a variable geometry mechanism of an engine are described herein. An engine control request indicative of a desired output power for the engine is monitored. A rate of change of the engine control request is determined. The rate of change is compared to a threshold. Responsive to determining that the rate of change is beyond the threshold, a transient bias map is applied to a steady-state schedule to generate a variable geometry mechanism request indicative of a target position for the variable geometry mechanism. The variable geometry mechanism is adjusted toward the target position according to the variable geometry mechanism request.

A single drive, dual clutch accessory drive system for an aircraft including an input shaft connected to a low pressure spool of a turbine engine. The input shaft is rotatable at a first input speed and at a second input speed that is distinct from the first input speed. An output shaft is operatively connected to an aircraft accessory. A first drive path operatively connects the input shaft and the output shaft. The first drive path includes a first clutch and a gear system. The first drive path is operable to adjust the first input speed to a selected output shaft speed. A second drive path operatively connects the input shaft and the output shaft. The second drive path includes a second clutch. The second drive path is operable to rotate the output shaft at the second input speed.

A method for controlling a turbomachine comprising an electric motor forming a torque injection device on a high-pressure rotation shaft, in which method a fuel flow setpoint Q.sub.CMD and a torque setpoint TRQ.sub.CMD provided at the electric motor are determined, the control method comprising: • a step of implementing a first fuel control loop in order to determine the fuel flow set point QCMD, • a step of implementing a second, torque control loop in order to determine the torque setpoint TRQ.sub.CMD comprising i. a step of determining a torque correction variable ΔTRQ.sub.CMD as a function of a transitory speed setpoint NHTrajAccelCons, NHTrajDecelCons and ii. a step of determining the torque setpoint TRQ.sub.CMD as a function of the torque correction variable ΔTRQ.sub.CMD.

Systems and methods for controlling an auxiliary power unit (APU) are provided. The systems and methods may comprise detecting an operating condition of the APU, determining an optimal APU frequency in response to the operating condition, and setting an angular velocity of the APU to the optimal APU frequency.

A fan array fan section in an air-handling system includes a plurality of fan units arranged in a fan array and positioned within an air-handling compartment. One preferred embodiment may include an array controller programmed to operate the plurality of fan units at peak efficiency. The plurality of fan units may be arranged in a true array configuration, a spaced pattern array configuration, a checker board array configuration, rows slightly offset array configuration, columns slightly offset array configuration, or a staggered array configuration.

An air compressing system is provided that includes a compressor configured to compressor air. An engine is operatively connected to the compressor. Further, an infinitely variable transmission is operatively connected between the engine and the compressor. A first shaft operatively connects the engine to the infinitely variable transmission and is configured to rotate at a first speed and a second shaft operatively connects the infinitely variable transmission to the compressor and is configured to rotate at a second speed.