Special Coverage

Lightweight, Flexible Thermal Protection System for Fire Protection
High-Precision Electric Gate for Time-of-Flight Ion Mass Spectrometers
Polyimide Wire Insulation Repair System
Distributed Propulsion Concepts and Superparamagnetic Energy Harvesting Hummingbird Engine
Wet Active Chevron Nozzle for Controllable Jet Noise Reduction
Magnetic Relief Valve
Active Aircraft Pylon Noise Control System
Unmanned Aerial Systems Traffic Management

Wireless Measurement of Rotation and Displacement Rate

A magnetic field response sensor is used in these measurements. A magnetic field response sensor is designed to measure displacement or rotation rate without a physical connection to a power source, microprocessor, data acquisition equipment, or electrical circuitry. The sensor works with the magnetic field response recorder, which was described in “Magnetic- Field- Response Measurement- Acquisition System,” NASA Tech Briefs, Vol. 30, No. 6 (June 2006), page 28. These sensors are wirelessly powered and interrogated, and the measurement acquisition system and sensors are extremely lightweight.

Posted in: Briefs, Electronics & Computers


Portable Microleak-Detection System

Heating or cooling of a vacuum seal enables testing over a wide temperature range. The figure schematically depicts a portable microleak-detection system that has been built especially for use in testing hydrogen tanks made of polymer-matrix composite materials. (As used here, “microleak” signifies a leak that is too small to be detectable by the simple soap-bubble technique.) The system can also be used to test for microleaks in tanks that are made of other materials and that contain gases other than hydrogen. Results of calibration tests have shown that measurement errors are less than 10 percent for leak rates ranging from 0.3 to 200 cm3/min.

Posted in: Briefs, Physical Sciences


Cryogenic Shrouds for Testing Thermal-Insulation Panels

These shrouds enable maintenance of required thermal and mechanical conditions. Cryogenic shrouds have been designed and built for use in thermo- mechanical testing of samples of thermal- insulation panels on cryogenic vessels. In the original application for which these shrouds were specifically designed, the samples are representative of the large area thermal- insulation panels on the space-shuttle external tanks that hold liquid hydrogen and liquid oxygen, and the purpose of the testing is to demonstrate the ability of bonded layers in the panels to resist delamination under a combination of applied uniaxial mechanical loads and realistic operational temperatures. Presumably, the shrouds and the tests performed by use of them could be modified to enable similar evaluation of thermomechanical properties of thermal- insulation panels for cryogenic vessels other than the external tanks of the space shuttles.

Posted in: Briefs, TSP, Physical Sciences


Free-to-Roll Testing of Airplane Models in Wind Tunnels

Causes of, and cures for, wing-drop/rock behavior can be evaluated. A free-to-roll (FTR) test technique and test rig make it possible to evaluate both the transonic performance and the wing-drop/rock behavior of a high-strength airplane model in a single wind-tunnel entry. The free-to-roll test technique is a single degree-of-motion method in which the model is free to roll about the longitudinal axis. The rolling motion is observed, recorded, and analyzed to gain insight into wing-drop/rock behavior.

Posted in: Briefs, TSP, Mechanical Components, Mechanics


Modeling Metamaterials Leads to Advance in Cloaking System Prototype

In efforts to use metamaterials to construct the world’s first working prototype of an invisibility cloak, researchers relied on multiphysics software. Modeling software is generally used to show the fields and flows that are impossible to see with the eye or instruments. A group of researchers has done just the opposite: They ran computer simulations that showed it should be possible to fabricate the metamaterials necessary to build an “invisibility cloak” that makes an object invisible to certain frequencies.

Posted in: Briefs, Materials


Freeze Tape Casting of Functionally Graded Porous Ceramics

Pore structures can be tailored in ways heretofore impossible. Freeze tape casting is a means of making preforms of ceramic sheets that, upon subsequent completion of fabrication processing, can have anisotropic and/or functionally graded properties that notably include aligned and graded porosity. Freeze tape casting was developed to enable optimization of the microstructures of porous ceramic components for use as solid oxide electrodes in fuel cells: Through alignment and grading of pores, one can tailor surface areas and diffusion channels for flows of gas and liquid species involved in fuel-cell reactions. Freeze tape casting offers similar benefits for fabrication of optimally porous ceramics for use as catalysts, gas sensors, and filters.

Posted in: Briefs, TSP, Manufacturing & Prototyping


Electrophoretic Deposition on Porous Non-Conductors

EPD is simplified and made more widely applicable. A method of electrophoretic deposition (EPD) on substrates that are porous and electrically non-conductive has been invented. Heretofore, in order to perform an EPD, it has been necessary to either (1) use a substrate material that is inherently electrically conductive or (2) subject a non-conductive substrate to a thermal and/or chemical treatment to render it conductive.

Posted in: Briefs, TSP, Manufacturing & Prototyping


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