USA as Represented by Secretary of the Navy

Other

Robert E Richardson

Michael B Slocum

Arturo M Lopez

Reginald I Gray

An apparatus is provided for determining an electromagnetic (EM) characteristic of a material, including a chamber, an antenna, a transmitter, a receiver and a processor. The chamber includes a permanent boundary that encloses a volume; a removable panel along the boundary. The panel includes the material. The antenna is disposed in the chamber for transmitting source EM radiation and receiving reflected EM radiation. The transmitter injects the source EM radiation via the antenna into the chamber. The source EM radiation includes continuous wave (CW) and pulse signals. The receiver obtains reverberated EM radiation from the chamber via the antenna and produces an intermediate frequency signal. The processor controls the transmitter and the receiver. The processor determines a decay time of the EM radiation from the intermediate frequency signal. The material is a test substance for comparison with a calibration reference substance on the removable panel having an established EM characteristic in the chamber, based on the decay time for the reference substance. The processor determines the EM characteristic from a decay time of the test substance and a reference decay time of the reference substance.

Electromagnetic surface resistivity determination

A back scrubber includes a substantially U-shaped bracket including an elongated vertical base plate with an upper arm and a lower arm perpendicularly extending therefrom. Removably positioned between the upper and lower arms is a tubular brush member that is automatically rotated with an internal electric motor. A bather can cleanse his her or back by activating the motor and placing the back against the brush member.

Back scrubber

A measuring system is disclosed which detects and measures the volume concentration and mass flow of the airborne conductive particles, such as carbon-absorptive chaff particles. The measuring system can be used to estimate the effective conductivity of the detected airborne conductive particles. Further, if particles are not airborne, but are lying on a surface they may be made to become airborne by the vacuum source of the present invention and then detected by the measuring system of the present invention.

Device to detect and measure the concentration and characterization of airborne conductive or dielectric particles

An apparatus for contactlessly measuring the electrical resistance per unit ength of a low-resistance test conductor (e.g., wire or cable) at a selected measurement frequency, which includes a coaxial cavity structure having a central cavity region defined by opposed first and second outer conductor sections, and a center conductor, wherein the test conductor comprises the center conductor. An input probe disposed adjacent to the first one of the outer conductor sections launches a standing wave on the center conductor, and an output probe disposed adjacent to the second one of the outer conductor sections senses the Q of the central cavity region. A detector coupled to the output probe measures the sensed Q of the central cavity region. The electrical resistance per unit length of the test conductor at the selected measurement frequency can be determined from the measured cavity Q. Also disclosed is an apparatus for contactlessly measuring the electrical resistance per unit length of a high-resistance test conductor, which includes a coaxial transmission line structure having an outer conductor having a central low impedance propagation region and input and output high impedance regions adjacent to opposite ends of the propagation region, and a center conductor, wherein the test conductor comprises the center conductor. An input probe disposed in the input high impedance region launches a traveling wave on the center conductor. An output probe disposed in the output high impedance region senses the attenuation of the traveling wave after it has propagated through the propagation region. First and second ferrite trap sections disposed adjacent to the input and output high impedance regions, respectively, serve to minimize the corruption of electrical resistance measurements due to electrical and/or physical phenomena which may occur in the environment external to the apparatus. A detector coupled to the output probe measures the sensed attenuation of the traveling wave. The electrical resistance per unit length of the test conductor at a selected measurement frequency can be determined from the measured attenuation of the traveling wave.

Apparatus for contactless measurement of the electrical resistance of a

An improved microwave pulsed and computer-operated resonance chamber system for obtaining various parameters for a multimode chamber with or without a specimen therein. The system is generally made up of a continuous microwave signal source arrangement for transmitting a series of pulses to the interior of the chamber at one point thereof. A detector for sensing a transient relaxation response curve after each pulse in the chamber where the sensing is effected at a second point in the chamber and where the curve is representative of the relative field strength in the chamber. In one embodiment of the system the carrier frequency of the series of pulses is selectively adjusted so as to alter the multimode characteristics of the chamber in order to provide different transient relaxation response curves by the chamber. In a second and third embodiment of the system, selective rotatable tuning means is provided at a third relatively spaced point in the chamber for altering the mode characteristics thereof. Regardless of the embodiment of the system, analyzer means and a computer arrangement is provided for advantageously determining a series of ensemble averaged mean squared voltage values in relation to time from selected groups of digitized and squared data points where the data points stem from a series of analyzed response curves and where the determined values enable the determination of various parameters of the multimode chamber, namely the equivalent single mode response and its calibration factor with or without a specimen therein.

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King George, VA, United States of America

Robert E Richardson