Southwest Research Institute

Charles H Parr

William A Mallow

Charles K Baker

Ruell F Solberg, Jr

Howard S Silvus, Jr

Jerome J Dziuk, Jr

Steven P Saulnier

Patrick J Siemsen

Dayle D Winnie

A direction-finding antenna constructed from polymer composite materials which are electrically conductive is shown with the polymer composite materials replacing traditional metal materials. An inherent advantage of replacing metal materials is significantly lower radar reflectivity (radar cross section) and lower weight. The reduced radar reflectivity reduces the range of detectability of the antenna by possible adversaries. Despite significantly lower radar reflectivity, the antenna assembly has direction-finding characteristics which are essentially equivalent to traditional metal antennas.

Polymer, composite, direction-finding antenna

The present invention provides a method and structure for absorbing shock in a load bearing prosthesis, particularly in a load-bearing skeletal prosthesis. Where the prosthesis is a hip-joint replacement, the invention provides a method and structure for absorbing shock (1) at the interface between the femoral head and cup, and (2) at the interface between the femur and the stem of the prosthesis. Where the prosthesis is a femoral head prosthesis, the prosthesis is formed using two separate components which are mechanically connected using an elastomeric component. The connection permits relative motion between the structural components of the prosthesis, with the elastomeric component acting as a passive shock absorbing element.

Shock absorbing element for a load bearing prosthesis

Apparatus and method for determining the amount of oxidative and hydrolytic degradation in the surface of a highly resistive material, such as a polymer. A special probe provides an annular resistance on the surface of a sample of the material. The voltage drop across the sample determines the input to a meter circuit. A guard circuit has an applied voltage that is substantially the same as the voltage at the meter circuit input. This circuitry permits a very low voltage source to be used.

Surface resistivity meter for determining surface degradation of high

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San Antonio, TX, United States of America

Charles H Parr