Physical Sciences

A lightweight, battery-powered sensor was developed for measuring cloud water content, which is the amount of liquid or solid water present in a cloud, generally expressed as grams of water per cubic meter. This sensor has near-zero power consumption and can be flown on standard...

A fully integrated, compact, adaptive space optic mirror assembly has been developed, incorporating new advances in ultralight, high- performance composite mirrors. The composite mirrors use Q-switch matrix architecture- based pixelized control (PMN-PT) actuators, which achieve high-...

There was an update on the subject of two previous NASA Tech Briefs articles: “Compact, Highly Stable Ion Clock” (NPO-43075), Vol. 32, No. 5 (May 2008), page 63; and “Neon as a Buffer Gas for a Mercury-Ion Clock” (NPO-42919), Vol. 32, No. 7 (July 2008), page 62. To recapitulate: A...

A theoretical study was performed addressing the degree of applicability or inapplicability, to a real gas, of the occasionally stated belief that for an ideal gas, incompressibility is synonymous with a zero or very low Mach number. The measure of compressibility used in this study is the...

Three device improvements have been developed that dramatically enhance the contrast ratio of microshutters. The goal of a microshutter is to allow as much light through as possible when the shutters are in the open configuration, and preventing any light from passing through...

Experiments have shown that significant fractions of uranium, lead, and possibly other toxic and/or radioactive substances can be removed from an aqueous solution by simply exposing the solution, at ambient temperature, to a treatment medium that includes weathered volcanic ash from Pu’u...

Water vapor absorption is ubiquitous in the infrared wavelength range where photoacoustic trace gas detectors operate. This technique allows for discontinuous wavelength tuning by temperature-jumping a laser diode from one range to another within a time span suitable for photoacoustic calibration. The...

A simple technique has been devised for making small, permanent changes in the eigenfrequencies (resonance frequencies) of whispering-gallery-mode (WGM) dielectric optical resonators that have high values of the resonance quality factor (Q). The essence of the technique is to coat the...

The short-term instability in the frequency of a linear-ion-trap frequency standard (LITS) can be reduced by modifying two cycles involved in its operation: (1) the bimodal (bright/dim) cycle of a plasma discharge lamp used for state preparation and detection and (2) a...

A dual cryogenic capacitive density sensor has been developed. The device contains capacitive sensors that monitor two-phase cryogenic flow density to within ±1% accuracy, which, if temperature were known, could be used to determine the ratio of liquid to gas in the line. Two of these density sensors,...

Two types of temperature sensors have been developed for wide-range temperature applications. The two sensors measure temperature in the range of –190 to +200 °C and utilize a thin-film platinum RTD (resistance temperature detector) as the temperature-sensing element. Other parts...

The need for autonomous navigation and intelligent control of unmanned sea surface vehicles requires a mechanically robust sensing architecture that is watertight, durable, and insensitive to vibration and shock loading. The sensing system developed here comprises four black and...