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Physical Sciences

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Briefs: Physical Sciences
Vacuum Leak Detection Using Piezoelectric Film

A technique for detecting a small leak of gas into a vacuum involves the use of a diaphragm made of a thin film of poly (vinylidene fluoride) [PVDF]. To exploit the piezoelectricity of PVDF for this purpose, both sides of the film are coated with thin, electrically conductive layers that serve as...

Briefs: Physical Sciences
Quasi-Decoupling of Shvab-Zel’dovich Variables

A paper presents some novel conclusions concerning the Shvab-Zel’dovich (SZ) vari- ables, which are linear combinations of dep- endent variables in mathematical models of multicomponent, chemically reacting flows. The SZ variables represent scalar quantities that are conserved, that is, are not...

Briefs: Physical Sciences
Assessing Energetic-Ion Effects Using Energetic Protons Only

Two reports describe a method of assessing the susceptibility of digital electronic equipment to upsets (bit errors) caused by impingement of energetic ions (both protons and heavier ions) in outer space.

The method, which is applicable at the single-component, circuit-board,...

Briefs: Physical Sciences
System For Measuring Osmotic Transport Properties of a Membrane

The membrane test cell (MTC) is an automated laboratory apparatus that applies a known osmotic potential across a membrane and measures the kinetics of the resulting transport of solvents across the membrane as a function of time. Data acquired by use of the MTC should prove...

Briefs: Physical Sciences

The figure schematically depicts a proposed achromatic nulling beam combiner. This instrument is intended for use in astronomy - principally, for attenuating light from stars or other bright...

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Briefs: Physical Sciences

A method has been developed to increase the accuracy of estimates of phase differences attributable to the optical-path-length difference between the arms of a long-baseline,...

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Briefs: Physical Sciences
Regulating Pressure-Volume Control of a Gas Blanketing Liquid R-124

A system for storing and circulating a refrigerant liquid [R- 124 (chloro- tetrafluoroethane)] includes a reservoir and a subsystem that regulates the pressure of nitrogen gas in the head space of the reservoir. The purpose of the pressurization is to prevent cavitation in a...

Briefs: Physical Sciences
Ellipsoidal Collecting Horns for Ultrasonic Leak Detectors

Ellipsoidal reflectors have been proposed as collecting horns for ultrasonic leak detectors. Exploiting the classical focusing characteristics of ellipsoids, these reflectors would facilitate and enhance the detection of leaks in situations in which it is possible to bring leak-detecting...

Briefs: Physical Sciences

The figure depicts a single-arm, slabwave- guide interferometer that has been demonstrated to be useable as a means of sensing ammonia in wet air. The slabwaveguide portion of this...

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Briefs: Physical Sciences

Improved electrical resistance heaters for preventing the accumulation of ice on aircraft surfaces are undergoing development. The primary intended market for these heaters is that of...

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Briefs: Physical Sciences

A previously developed quality/flow meter has been redesigned to improve its performance as a device for measuring the quality (but not the flow) of two-phase (liquid + vapor) oxygen or...

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Briefs: Physical Sciences

Electrohydrodynamic (EHD) conduction pumps have been investigated in theoretical and experimental studies. In general, EHD pumps contain no moving parts. They generate pressure gradients and/or flows in...

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Briefs: Physical Sciences
Infrared Fiber-Optic Endoscope

A proposed infrared transmitting fiber-optic endoscope, which would partly resemble a visible-light fiber-optic endoscope, instrument could be used to perform thermal imaging in harsh environments and/or confined spaces in a variety of situations in aerospace, industrial, automotive, and medical settings.

Briefs: Physical Sciences

A technique similar to that of metallography has been devised for preparing cross-sectional micrographic specimens from small samples cut from oil paintings. Art experts at the...

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Briefs: Physical Sciences
Electrostatic Systems Keep Dust Off Surfaces

Electrostatic dust- collection systems that comprise wire grids connected to lightweight, low-power high-voltage sources have been invented for preventing the accumulation of dust on surfaces. Intended originally for use in keeping spacecraft solar panels free of dust, these systems could also be used...

Briefs: Physical Sciences

Optical Fourier-plane analysis may prove useful for obtaining statistical data on the densities, sizes, shapes, indices of refraction, and perhaps other properties of particles...

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Briefs: Physical Sciences

Gauges made of slugs of pyrolytic graphite with thermocouples em- bedded in them have been invented for use in measuring large, short-duration heat fluxes in hot, highly corrosive...

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Briefs: Energy

In support of NASA’s Environmental Research Aircraft and Sensor Technology (ERAST) program, flight tests of the Pathfinder solar-electric-powered, remotely...

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Briefs: Physical Sciences
System for Detecting Hazardous Gases at Multiple Locations

The Hazardous Gas Detection System 2000 (HGDS 2000) is the latest in a series of instrumentation systems for detecting gases leaking from a space shuttle on a launch pad. The HGDS is a fully redundant system that includes analog and digital electronic control circuitry and a sub- system...

Briefs: Physical Sciences
Narrowband Tunable Optical Filter Using Fiber Bragg Gratings

Research at Langley Research Center has developed a special fiber- Bragg grating optical filter for use in aircraft or spaceborne differential absorption lidar (DIAL) systems for measuring water vapor in the atmosphere of the Earth. The filter is an optical fiber containing two Bragg...

Briefs: Physical Sciences

A relatively simple and inexpensive method of fabricating a temperature-compensation element for high- temperature strain gauges has been devised. This element, connected in...

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Briefs: Physical Sciences

An instrumentation system measures the concentrations of three principal contaminants (nonvolatile residue, hydrocarbon vapor, and particle fallout) in real time. The system...

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Briefs: Physical Sciences

Scientists at NASA's Jet Propulsion Laboratory are developing apparatuses for electrolysis of methanol to produce pure hydrogen for use at industrial sites, in scientific laboratories, and in fuel...

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Briefs: Physical Sciences

An aircraft-mounted instrument for high- resolution, in situ measurement of the abundances of liquid water and ice in clouds is undergoing development. This instrument is intended to overcome the...

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Briefs: Physical Sciences

Miniature, lightweight nuclear-magnetic-resonance (NMR) spectrometers suitable for characterizing ferromagnetic minerals in the field are undergoing development. In previously developed miniature...

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Briefs: Test & Measurement
Low-Power, Zero-Vibration Sorption Coolers

A report discusses three designs of proposed low-power, zero-vibration coolers for infrared instruments planned to be flown aboard spacecraft to perform astrophysical observations far from Earth. The designs take advantage of the radiative precooling available in the projected deep-space operational...

Briefs: Research Lab
Inhibited Carrier Transfer in Ensembles of Quantum Dots

A report presents an experimental study of time-resolved, temperature-dependent photoluminescence in InxGa1–x As/GaAs specimens containing In0.6Ga0.4As quantum dots (QDs) distributed at several different areal densities on a GaAs surface and...

Briefs: Physical Sciences
Area Production in Supercritical, Transitional Mixing Layers

This paper presents a study of area production in mixing layers undergoing transition to turbulence. These layers evolve from the mixing of two initially segregated counterflowing streams under supercritical conditions. The study may contribute to development of means to control area...

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