Tech Briefs

Electrical-Impedance-Based Ice-Thickness Gauges

Compact, inexpensive gauges provide early warnings of accretion of ice. Langley Research Center has developed electrical- impedance- based icethickness gauges and is seeking partners and collaborators to commercialize them. When used as parts of active monitoring and diagnostic systems, these gauges make it possible to begin deicing or to take other protective measures before ice accretes to dangerous levels. These gauges are inexpensive, small, and simple to produce. They can be adapted to use on a variety of stationary and moving structures that are subject to accumulation of ice. Examples of such structures include aircraft, cars, trucks, ships, buildings, towers, power lines (see figure), power-generating equipment, water pipes, freezer compartments, and cooling coils.

Posted in: Briefs, TSP

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System for Testing Thermal Insulation of Pipes

Thermal and flow conditions are carefully controlled to minimize errors. An apparatus and method have been developed for measuring the rates of leakage of heat into pipes carrying liquids, the purpose of the measurements being to quantify the thermal performance of the insulation system. The apparatus is designed primarily for testing pipes used to carry cryogenic liquids, but can also be used for measuring the thermal performance of other insulated pipes or piping systems.

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Brushless DC Rotary Motor Improves Efficiency in Fuel Cell Applications

Design uses thin- walled stator to achieve high power density. The designers and manufacturers of fuel cells are continually striving to improve the efficiency of their products. A design challenge facing the engineer relates to reducing the power demands of the many electrical systems that support fuel cell operation. Blowers, compressors, and pumps are necessary for fuel pump operation, but are considered parasitic electrical loads. Since they require power from the fuel cell itself they impact overall system efficiency. To be truly effective in fuel cell applications, the motors used to drive the pumps must be lightweight, compact, and as efficient as possible in order to provide more energy for the intended application.

Posted in: Manufacturing & Prototyping, Briefs

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Exercise Device Would Exert Selectable Constant Resistance

An apparatus called the resistive exercise device (RED) has been proposed to satisfy a requirement for exercise equipment aboard the International Space Station (ISS) that could passively exert a selectable constant load on both the outward and return strokes. The RED could be used alone; alternatively, the RED could be used in combination with another apparatus called the treadmill with vibration isolation and stabilization (TVIS), in which case the combination would be called the subject load device (SLD). The basic RED would be a passive device, but it could incorporate an electric motor to provide eccentric augmentation (augmentation to make the load during inward movement greater than the load during outward movement). The RED concept represents a unique approach to providing a constant but selectable resistive load for exercise for the maintenance and development of muscles. Going beyond the original ISS application, the RED could be used on Earth as resistive weight training equipment. The advantage of the RED over conventional weight-lifting equipment is that it could be made portable and lightweight.

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Simulation of MEMS Piezoelectric Micropump for Biomedical Applications

University of Alberta uses simulation software for multiphysics analysis. Since the advent of Micro Electro Mechanical Systems (MEMS) technology, microfabrication methods have been used to manufacture a wide range of miniature pumps. These micropumps find their greatest use in chemical and biomedical applications requiring the transport of small, accurately measured liquid quantities. When utilized in chemical applications, micropumps are often a component of a lab-on-a-chip device. Such devices are envisioned as providing for reasonably inexpensive, possibly even disposable, means to conduct laboratory experiments.

Posted in: Bio-Medical, Briefs

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Ultrasonic/Sonic Mechanisms for Drilling and Coring

These mechanisms imitate burrowing actions of gophers and crabs. Two apparatuses now under development are intended to perform a variety of deep-drilling, coring, and sensing functions for subsurface exploration of rock and soil. These are modified versions of the apparatuses described in "Ultrasonic/Sonic Drill/Corers With Integrated Sensors" (), NASA Tech Briefs, Vol. 25, No. 1 (January 2001), page 38. In comparison with the drilling equipment traditionally used in such exploration, these apparatuses weigh less and consume less power. Moreover, unlike traditional drills and corers, these apparatuses function without need for large externally applied axial forces.

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Advances in Thrust-Based Emergency Control of an Airplane

It should be possible to land safely after a primary-flight-control failure. Engineers at NASA's Dryden Flight Research Center have received a patent on an emergency flight-control method implemented by a propulsion-controlled aircraft (PCA) system. Utilizing the pre-existing auto-throttle and engine-pressure-ratio trim controls of the airplane, the PCA system provides pitch and roll control for landing an airplane safely without using aerodynamic control surfaces that have ceased to function because of a primary-flight- control-system failure. The installation of the PCA does not entail any changes in pre-existing engine hardware or software. [Aspects of the method and system at previous stages of development were reported in "Thrust-Control System for Emergency Control of an Airplane" (DRC-96-07), NASA Tech Briefs, Vol. 25, No. 3 (March 2001), page 68 and "Emergency Landing Using Thrust Control and Shift of Weight" (DRC-96-55), NASA Tech Briefs, Vol. 26, No. 5 (May 2002), page 58.]

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