Abstract: A material-actuated door includes a door housing including a flexible material; and one or more least one Shape Memory Alloy (SMA) actuators embedded in the door housing. Each SMA actuator is elastically biased in a first actuator physical state and is configured to transition into a second actuator physical state in response to receiving electrical current. The material-actuated door is transitioned into a first door position in response to disconnecting the electrical current to the at least one SMA actuator, and is transitioned into a second door position in response to delivering the electrical current to the at least one SMA actuator.

Abstract: A system estimates flow parameters associated with a fluid flow encountering a bluff body. The system includes multiple sensors distributed on a surface of a bluff body. The system further includes input circuitry and a sensor processing unit. The input circuitry receives a signal from each of the multiple sensors. The sensor processing unit determines noise levels associated with each of the multiple sensors due to the fluid flow encountering the bluff body. The sensor processing unit further assigns weights to each of the multiple sensors based on the determined noise levels and estimates the fluid flow direction based on the assigned weights.

Abstract: A system and method for reducing acoustic, wind or other background noise that may interfere with sensing of a seismic signal is provided. More specifically, a shield is provided to enclose a geophone and thereby protect it from harmful noise. The shield may comprise a rigid shell, a structural damping material, an acoustically absorptive material, and a compliant seal for coupling the shield to the ground or reference surface.

Abstract: A system (400) for reducing non-acoustic noise includes a primary sensor (420), at least one secondary sensor (410), a filter (415), and a summation unit (425). The primary sensor (420) measures pressure and produces a primary pressure signal. The at least one secondary sensor (410) measures pressure and produce a secondary pressure signal. The filter (415) processes the secondary pressure signal to produce a filtered pressure signal. The summation unit (425) subtracts the filtered pressure signal from the primary pressure signal to reduce non-acoustic noise in the primary pressure signal.

Abstract: A system for rejecting wind noise at a plurality of sensors includes input logic, a processor and output logic. The input logic receives a signal from each of the plurality of sensors. The processor assigns a weight value to each of the received signals. The output logic derives a wind noise rejected output signal based on a function of the assigned weight values and the received signals.

Abstract: An active control device for reducing high-speed impulsive (“HSI”) and blade vortex interaction (“BVI”) noise in a rotor aircraft, such as a helicopter, is disclosed. The system comprises a plurality of rotor blades extending radially in spaced relationship from a central hub, each of the blades having spaced apart upper and lower surfaces, an interior volume between the surfaces, and leading and trailing edges at the respective joined edges of the upper and lower surfaces. Air intake passages are disposed on the surfaces of each blade proximate the leading edge to controllably admit air into the interior volume; and air output passages are disposed on the surfaces of each blade proximate the trailing edge and the outer edge tip to controllably expel air from the interior volume of the blade. Admitting and expelling of air into and out of the interior volume of each blade is controlled in accordance with a determined condition of that blade.