Michael B Duncan

US Patent:

60416424, Mar 28, 2000

Filed:

Jun 4, 1998

Appl. No.:

9/090365

Inventors:

Michael G. Duncan - Clinton TN

Assignee:

Lockheed Martin Energy Systems, Inc. - Oak Ridge TN

International Classification:

G01N 2700

US Classification:

73 2401

Abstract:

A method and apparatus for measuring the natural resonant frequency of a spring element by monitoring a phase difference between an output signal from the spring element and an input signal to the spring element and by adjusting frequency of the input signal until a detected phase difference signals that the natural resonant frequency has been reached. The method and apparatus are applied to a micro-cantilevered elements used to measure gas compositions and concentrations. Such elements are provided with coatings that absorb gas to cause deflections and changes in the mass or spring constant of the cantilevered element. These changes correspond to changes in the natural resonant frequency of the cantilevered element which are measured using the method and apparatus described herein.

US Patent:

42504716, Feb 10, 1981

Filed:

May 1, 1978

Appl. No.:

5/901421

Inventors:

Michael G. Duncan - Clinton TN

International Classification:

H04B 164

US Classification:

333 14

Abstract:

This invention discloses new and unique detectors suitable for controlling any device needing precise conversion of AC voltage to an equivalent DC voltage. The detector may also be used as an excellent non-linear low pass filter. More particularly, the detector is suitable for controlling meter movements and the variable gain amplifiers which are used in compressors, expanders, compandors, limiters and other noise reduction systems, The detectors control gain such that unnecessary gain changes are eliminated, overshoot transient distortion is minimized, distortion due to ripple is minimized, and pumping is eliminated. As described herein, the detector uses two interacting memories to provide a output signal from the detector which can be used to drive a variable gain amplifier for achieving optimum characteristics of a compressor, expandor or compandor. This is achieved by using inter-connecting circuitry between the two memories and between the inputs and outputs of the detector such that one of the memories dominates and controls the output signal for most input voltage situations, but in the event of drastic input signal changes the second memory interreacts with the first memory.

US Patent:

58255010, Oct 20, 1998

Filed:

Mar 14, 1997

Appl. No.:

8/818157

Inventors:

David K. Mee - Knoxville TN
Glenn O. Allgood - Powell TN
Larry R. Mooney - Knoxville TN
Michael G. Duncan - Clinton TN
John C. Turner - Clinton TN
Dale A. Treece - Knoxville TN

Assignee:

Lockheed Martin Energy Systems, Inc. - Oak Ridge TN

International Classification:

G01N 2184

US Classification:

356429

Abstract:

A structure and yarn sensor for fabric directly determines pick density in a fabric thereby allowing fabric length and velocity to be calculated from a count of the picks made by the sensor over known time intervals. The structure and yarn sensor is also capable of detecting full length woven defects and fabric. As a result, an inexpensive on-line pick (or course) density measurement can be performed which allows a loom or knitting machine to be adjusted by either manual or automatic means to maintain closer fiber density tolerances. Such a sensor apparatus dramatically reduces fabric production costs and significantly improves fabric consistency and quality for woven or knitted fabric.