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TRANSVERSE PIEZORESISTANCE AND PINCH
EFFECT ELECTROMECHANICAL

TRANSDUCERS

NASA Case No. ERC-10088

Canada

Address inquiries to:
NASA Headquarters
Code GP
Washington, DC 20546
U.S.A.

(Corresponding U.S. Patent No. 3,537,305)

This invention is a replacement for strain gages and accelerometers. The device may be used in any environment where conventional piezoresistive or strain gage electromechanical transducers can be used. In addition to the foregoing uses, the device can be used in bioelectric sensing due to its small size. The transducer, of anisotropic piezoresistive material, includes a body of semiconductor material having a longitudinal force axis that is skewed with respect to the crystallographic orientation of the body. The material combines the pinch effect with the piezoresistive effect. The device produces a much larger electrical signal for a given stress than presently known in the prior art.

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FIRE RETARDANT FOAMS

NASA Case No. ARC-10098

*See address below.

Australia, Belgium, Canada, France,
Italy, Japan, Sweden, Switzerland,
Great Britain, West Germany,
Netherlands

(Corresponding to U.S. Patent No. 3,549,564)

This invention improves upon polyurethane foams as fire resistant materials by improving their characteristics and by imparting fire suppressant and fire retardant characteristics. The main structure of the material is a rigid or semi-rigid polyurethane foam, preferably of a highly branched structure, in which are incorporated one or more materials to impart special properties. Modified foams have been developed which provide effective protection for thermally sensitive structures against the destructive action of fuel-fires. The invention relates to the modification of closed cell rigid and semi-rigid polyurethane foams in the density range of from 0.50 to 50 pounds per cubic foot. The modifying agents include three types: a certain class of alkyl halide resins, a certain class of inorganic salts, and encapsulated halogen bearing volatile molecules. The modified foam may then be applied by conventional methods. Outstanding protection against fire has been achieved.

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*Exclusively licensed to Avco Corporation. Please direct inquiries to: Fire Protection Materials, Avco Corporation, Avco Systems Division, Lowell Industrial Park, Lowell, Massachusetts 01851.

INTUMESCENT PAINTS

NASA Case No. ARC-10099

*See address below.

Australia, Belgium, Canada, France,
Italy, Japan, Sweden, Switzerland,
Great Britain, West Germany,
Netherlands

(Corresponding to U.S. Patent No. 3,535,130)

Intumescent (swelling or expanding) paints useful for fire protection have been produced. Conventional intumescent paints suffer from many disadvantages including sensitivity to water and other solvents, little resistance to scuffing and abrasion, sensitivity to thermal erosion by flames, and limited efficiency in the protection of substrates under thin steel plate or sheet. This paint overcomes these disadvantages and provides outstanding protection. The intumescent material is an aromatic nitroamino compound in the form of its sulfate, either dissolved or dispersed in a vehicle, or prepolymerized, or both. Upon heating, such a paint intumesces, chars and provides a flame resistant coating.

*Exclusively licensed to Avco Corporation. Please direct inquiries to: Fire Protection Materials, Avco Corporation, Avco Systems Division, Lowell Industrial Park, Lowell, Massachusetts 01851.

UNSATURATING SATURABLE

CORE TRANSFORMER

NASA Case No. ERC-10125

Address inquiries to:

NASA Headquarters Canada, France, Netherlands,

Code GP Italy, Japan, Great Britain,

Washington, DC 20546 West Germany

U.S.A.
(Corresponding U.S. Patent No. 3,541,428)

The transformer of the present invention will not saturate at any time under any conditions for any length of time. The device includes a pair of stacked, uncut, saturable magnetic cores having a plurality of windings. The cores operate in parallel and provide a means of detecting, warning and suppressing any impending saturation before saturation can occur. Many advantages are gained from the use of this transformer such as: elimination of the main apparent cause of power transistor failure in inverter circuits while enabling existing power transistors to process double or more load current, and, enabling a better utilization of existing components because it reduces the need to derate switching components to a small fraction of their current carrying capacity.

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METHOD AND APPARATUS FOR MEASURING
THE DAMPING CHARACTERISTICS OF

A STRUCTURE
NASA Case No. ARC-10154

Address inquiries to:

Ames Research Center Canada, France, Japan,

Attn: Patent Counsel Great Britain, West Germany

Mail Code: 200-11A
Moffett Field, CA 94035
U.S.A.

(Corresponding to U.S. Patent No. 3,620,069) Spectral analyzers and correlation computers have been used in the past to provide the most useful damping data heretofore available; however, these types of apparatus either require too much time to obtain accurate values of damping characteristics or can only be used with linear systems. The present invention relates to an automatic on-the-line instrument for measuring the damping characteristics of a structure or system during excitation by random forces or influences. The apparatus is comprised of at least two parallel sampling circuits which perform time sequential sampling operations on predetermined portions of a given input signal. After summing the outputs of the sampling circuits at output terminals, a sampling transient indicative of a point on the damping characteristic of the structure can be obtained.

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