Physical Sciences

Fault-Tolerant Heat Exchanger

A single-point leak would not cause mixing of heat-transfer fluids.

Posted in: Physical Sciences, Briefs

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Optical Design of an Optical Communications Terminal

This airborne system would keep itself aimed at a ground station. An optical communications terminal (OCT) is being developed to enable transmission of data at a rate as high as 2.5 Gb/s, from an aircraft or spacecraft to a ground station. In addition to transmitting high data rates, OCT will also be capable of bidirectional communications. The OCT is meant to incorporate all of the design features of a prior apparatus denoted the Optical Communications Demonstrator (OCD), plus some improvements.

Posted in: Physical Sciences, Photonics, Briefs, TSP

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Atomic Clock Based on Opto-Electronic Oscillator

This apparatus would afford spectral purity plus long-term stability and accuracy.

Posted in: Physical Sciences, Briefs, TSP

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Microfocus/Polycapillary-Optic Crystallographic X-Ray System

This system generates an intense, nearly collimated beam suitable for crystallography.

Posted in: Physical Sciences, Briefs

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Depth-Penetrating Luminescence Thermography of Thermal-Barrier Coatings

Temperatures at depths can be measured by luminescence decay of suitable thermographic phosphors.

Posted in: Physical Sciences, Briefs, TSP

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Automated Counting of Particles To Quantify Cleanliness

A machine vision system, similar to systems used in microbiological laboratories to count cultured microbes, has been proposed for quantifying the cleanliness of nominally precisely cleaned hardware by counting residual contaminant particles. The system would include a microscope equipped with an electronic camera and circuitry to digitize the camera output, a personal computer programmed with machine-vision and interface software, and digital storage media.

Posted in: Physical Sciences, Briefs

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Compact Infrasonic Windscreen

High values of infrasound-transmission and wind-noise-attenuation coefficients can be realized. A compact windscreen has been conceived for a microphone of a type used outdoors to detect atmospheric infrasound from a variety of natural and man-made sources. Wind at the microphone site contaminates received infrasonic signals (defined here as sounds having frequencies <20 Hz), because a microphone cannot distinguish between infrasonic pressures (which propagate at the speed of sound) and convective pressure fluctuations generated by wind turbulence. Hence, success in measurement of outdoor infrasound depends on effective screening of the microphone from the wind.

Posted in: Physical Sciences, Briefs

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