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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Device consists of highly compliant circular beam attached to piezoresistive strain gage and barbed needle. Radial deflection of myocardium is measured with minimal disturbance of normal heart functions.
Optically-selective, acoustically-resonant, gas-detecting device is used to measure intensity of radiation-induced pressure variations. Use of diaphragm improves sensitivity and immunity to background noise.
Simple and inexpensive device, using solar cells, measures rapidly-responding active control surfaces of aeroelastically-scaled wind-tunnel models of aircraft. Device allows control surfaces to be measured to within 0.10 deg.
Inexpensive kit improves bond quality, saves time, and is used in hard-to-reach areas. Kit provides precise pressure loading, and allows pressure to be monitored during curing cycle.
The problem of operating a condenser microphone as a terminal element of a half wavelength transmission line was dealt with; the environment in which the microphone operates necessitates a 25 foot separation from its supporting electronics. A theoretical analysis of the microphone-cable system, substantiated by laboratory tests, provided criteria to optimize system gain.
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Device has been utilized in nondestructuive testing of low-density porous materials (e. g., high temperature surface insulation) for cracks.
Compact instrument has active and reference sides consisting of tubes that elongate in response to increasing interior pressures. Relative displacement of tubes is measured by linear variable differential transformer to determine pressure on active side. Device needs no internal cooling, thus eliminating condensation problem with gases containing saturated steam.
A condenser microphone AM carrier system, which has been developed to measure pressure fluctuations at elevated temperatures, consists of the following components: a condenser microphone designed for operation at elevated temperatures; existing carrier electronics developed under two previous research grants but adapted to meet present requirements; a 6 m cable operating as a half-wavelength transmission line between the microphone and carrier electronics; and a voltage-controlled oscillator used in a feedback loop for automatic tuning control. Both theoretical and practical aspects of the development program are considered. The three predominant effects of temperature changes are changes in the membrane-backplate gap, membrane tension, and air viscosity. The microphone is designed so that changes in gap and membrane tension tend to have compensating effects upon the microphone sensitivity.
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High-data-rate pressure sensor module can be calibrated after it is attached to an experimental setup. Electrically multiplexed sensor is designed for use in wind-tunnels and other applications requiring accurate measurement of many pressures in a short period of time.
It was found that ion beam texturing of silicon surfaces can be used to increase the effective surface area of MOS capacitors. There is, however, a problem with low dielectric breakdown. Preliminary work was begun on the fabrication of ion implanted resistors on textured surfaces and the potential improvement of wire bond strength by bonding to a textured surface. In the area of ion beam sputtering, the techniques for sputtering PVC were developed. A PVC target containing valinomycin was used to sputter an ion selective membrane on a field effect transistor to form a potassium ion sensor.
Flutter frequency was determined and rotor vibratory amplitude and phase distributions during flutter were reconstructed from stationary aerodynamic type measurements. A previously reported optical method for measuring blade-tip displacement during flutter was extended by means of digital analysis. Displacement amplitudes and phase angles were determined based on this method. For selected blades, spectral results were also obtained from strain gage measurements. The results from these three types of measurement were compared and critically evaluated.
Instrumentation was developed for the high altitude inflatable sphere to measure its skin temperature, acceleration and internal pressure. The sphere without instrumentation has routinely been used over the past 10 years to provide measurements of winds, density, temperature and pressure between 100 Km and 30 Km altitude. With the miniaturized instrumentation package onboard, the system offers the potential for providing meteorological information as well as a better understanding of sphere performance and dynamics during its descent. Of the six launches of instrumented spheres only one provided telemetry data. However, many of the objectives of the program were achieved.
A simple laser-based instrument is described which produces output voltages proportional to displacements in orthogonal directions. This instrument and the associated experimental techniques have been used to measure biaxial displacements across 400-micron slots at various angles in sheet specimens of various widths.
Matrix of pressure sensors determines shape and pressure distribution of object in contact with its surface. Output can be used to develop pressure map of objects' surface and displayed as array of alphanumeric symbols on video monitor.
Flutter frequency was determined and rotor vibratory amplitude and phase distributions during flutter were reconstructed from stationary aerodynamic type measurements. A previously reported optical method for measuring blade-tip displacement during flutter was extended by means of digital analysis. Displacement amplitudes and phase angle were determined based on this method. For selected blades, spectral results were also obtained from strain gage measurements. The results from these three types of measurement were compared and critically evaluated.