Abstract: A gas path component for a gas turbine engine includes a film cooling hole disposed in the gas path component. The film cooling hole includes a metering section, a diffuser, and a tapered surface extending between the metering section and the diffuser. The tapered surface is oriented between twenty degrees and seventy degrees with respect to a centerline axis of the metering section. The tapered surface is oriented at an obtuse angle with respect to an immediately adjacent surface of the diffuser, the obtuse angle is open towards the centerline axis. The tapered surface is configured to mitigate flow separation in the diffuser.

Abstract: A method for target identification includes receiving, at one or more processors, a number of measurements of a target, each measurement from the number of measurements being observed at a predetermined time (zk), a number of target types (T), each one of the number of measurements, each one the number of target type and each one of one or more hidden states, each hidden state (xk) being characterized at the predetermined time, being correlated to one another, providing, using the one or more processors, a first conditional probability distribution, a conditional probability of a target type given a number of measurements, defined inductively, and obtaining an estimate of the target type from the first conditional probability. Systems that implement the method are also disclosed.

Abstract: Systems that provide an active adjustment of mirrors and specifically of secondary mirrors, and that provide active adjustment of secondary mirrors in six degrees of freedom, and that can carry the additional load during launch.

Abstract: A shock-resistant device includes snubbers that may be selectively extended to selectively create a stiff attachment between a vibration-isolated component of the device, and another part of the device. The snubbers may be electromechanical or hydraulically driven. The device may be a sensor system for an unmanned aerial vehicle, with the snubbers extendible to create a stiff attachment between an inner gimbal and an outer shell of the sensor system, for example prior to landing the unmanned aerial vehicle on an aircraft carrier, or prior to transportation or storage of the unmanned aerial vehicle. The snubbers may be able to be manually actuated, even when the unmanned aerial vehicle has no power available.

Abstract: A system for protecting radio frequency (RF) communications and related techniques includes generating masking signals at an RF device such as a radio frequency identification (RFID) card.

Abstract: Disclosed subject matter relates to techniques for predicting jamming effectiveness. In one approach, platform models and propagation models are used to predict maximum threat communication range when jamming is used and when jamming is not used. The maximum range information may then be used to calculate jammer effectiveness. In another approach, probability-based techniques are used to predict jamming effectiveness for a system of interest.

Abstract: A method and system for detecting watercraft in shallow waterways. In one example, an underwater detection system includes an underwater power source, an acoustic sensor, a controller coupled to the power source and to the acoustic sensor and configured to detect a watercraft of interest based on acoustic signals generated by the watercraft of interest and received by the acoustic sensor, and a retractable communications system. The retractable communications system is configured to deploy a transmitter to the surface of the shallow water to report detection of a watercraft in the waterway and to retract the transmitter to a safe depth below the surface of the shallow waterway when not actively communicating.

Abstract: A technique for and structures for camouflaging an integrated circuit structure. The technique including forming active areas of a first conductivity type and LDD regions of a second conductivity type resulting in a transistor that is always non-operational when standard voltages are applied to the device.

Abstract: An imaging system uses a low coherence light source to image objects at a relatively far distance (at least 10 cm) and/or of a relatively large size (having a dimension of at least 10 cm). An imaging plane is located such that its image path is substantially equal to a reference path that the light follows within the imaging device. The imaging plane has a thickness of about the coherence length of the light. Only light returning from the imaging plane forms part of the image. Light returning on other paths is effectively negated due to a lack of coherence. The imaging plane may be a fixed distance from the imaging system. Alternatively, the imaging plane may be at a variable distance from the imaging system, with the reference path having a changeable length.

Abstract: A regenerative refrigeration system includes one or more control devices that utilize micro electro mechanical systems (MEMS) technology. Such MEMS devices may be small in size, on a scale such that it can be introduced into a refrigeration system, such as a cryocooler, without appreciably affecting the size or mass of the refrigeration system. Through the use of MEMS devices, dynamic control of the system may be achieved without need for disassembly of the system or making the system bulky. Suitable regenerative refrigeration systems for use with the MEMS devices include pulse tube coolers, Stirling coolers, and Gifford-McMahon coolers.

Abstract: An active array radar system is controlled by photonic signals. The array of N antenna elements is divided into M subarrays, each having N/M antenna elements. Tunable lasers provide M optical wavelengths within non-overlapping bands. For transmission, a microwave transmit pulse is amplitude modulated onto the M optical signals. Time delays are introduced for an offset between elements in a subarray and for an offset between subarrays. By using wavelength division multiplexing each antenna element on the array has a true time delay.

Abstract: A method for operating a radar system includes the steps of overlapping mainlobe clutter interference and feedthrough interference in a Doppler output signal of a coherent pulse Doppler radar including the step of phase modulating each pulse of a transmit signal wherein the selected phase modulation is derived from a linear phase ramp required to shift the mainlobe clutter interference into alignment with the feedthrough interference while being held constant over the duration of a pulse. With such an arrangement, the constant phase shift across each pulse has no effect on the performance of intrapulse compression modulation and results in pulse to pulse phase shifts easily being accomplished with existing phase shifters.

Abstract: A localized interference nulling preprocessor for a Fast Fourier Transform (FFT) or a Butler matrix system includes a means for forming a dot product of a signal vector and each of the preprocessed eigen vectors of the virtual interference covariance matrix of a predetermined localized interference, means for scaling the conjugate of the principal eigen vectors by the dot product, and means for subtracting from the signal vector the product of each dot product and conjugate of principal eigen vectors to generate a preprocess signal vector modified to produce a localized nulling of predetermined localized interference by a Fast Fourier Transform (FFT) or Butler matrix system.

Abstract: A system for detecting the presence of a fluid comprising: means for transmitting at least two infrared electromagnetic signals toward a fluid, each of the infrared electromagnetic signals have different wavelengths. It also includes means for sensing the reflection of each of the electromagnetic signals as well as means for creating a plurality of electrical signals indicating the intensity of the reflected signals. Finally, it includes means for determining the presence of said fluid by comparing the intensities of the plurality of electrical signals.

Abstract: Polymeric paraxylylene coatings and films possessing significantly improved oxidation resistance, particularly at elevated temperatures, are disclosed as well as a process for their preparation wherein certain antioxidants are vaporized and codeposited with vaporous poly(paraxylylene) precursors onto a substrate.