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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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At least 505 records · Page 28
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Determination of ILS category 2 decision height window requirements

A method for determining the appropriate longitudinal and lateral decision height dispersion limits for any airplane/control system combination during an instrument landing approach is presented. An example is worked out to clarify the steps required. It is shown that the current longitudinal decision height dispersion limits are well suited for a DC-8 with the example control system, but that the lateral limits are too loose to guarantee acceptable touchdowns with the example system subjected to recommended wind and shear disturbances.

Johnson, W. A.↗
NASA NTRS1972

Spectrophotometry of the 1.5-micron window of Jupiter.

The limb darkening of the 1.5-micron region and the variations of ammonia and methane absorptions over the Jovian belts, zones, and spots are studied on the basis of high-resolution infrared spectrometric data obtained for 86 areas on the Jovian surface. It is shown that the absorptions increase with increasing air mass between the equator and the poles, that they decrease linearly with increasing air mass between the central meridian and the limbs, and that the absorptions over the South Tropical Zone are greater and those over the Great Red Spot are smaller than the absorptions for other features. An ammonia absorption map of the planet is plotted for the period April-June, 1970.

Binder, A. B.↗
NASA NTRS1973

Mach-Zehnder optical configuration with Brewster window and two quarter-wave plates

Configuration is improvement because of the following: It provides higher efficiency. It reduces or eliminates feedthrough of untranslated local oscillator, which would produce a beat signal at shifted frequency of translator. When used without translator and with low-power detector, telescope secondary mirror reflects portion of output to local oscillator.

Lawrence, T. R.↗
NASA NTRS1974

Measurements of the short-term stability of quartz crystal resonators: A window on future developments in crystal oscillators

Recent measurements of the inherent short-term stability of quartz crystal resonators are presented. These measurements show that quartz resonators are much more stable for times less than 1s than the best available commercial quartz oscillators. A simple model appears to explain the noise mechanism in crystal controlled oscillators and points the way to design changes which should permit more than 2 orders of magnitude improvement in their short-term stability. Calculations show that a reference signal at 1 THz, derived from frequency multiplying a 5 MHz source with the above measured crystal stability, should have an instantaneous or fast linewidth of order 1 Hz. These calculations explicitly include the noise contribution of our present multiplier chains and are briefly outlined.

Walls, F. L.↗
NASA NTRS1976

Exposure damage mechanisms for KCl windows in high power laser systems

An experimental study of the 10.6 micrometer and 0.6328 micrometer optical properties of single crystal and europium doped polycrystal is described. Significant variations in the optical properties are observed over periods of exposure up to 100 hours. Models are proposed to predict the 10.6 micrometer absorptivity for long exposure periods. Mechanical creep has been detected in both materials at high temperature.

Blaszuk, P. R.↗
NASA NTRS1977

Window-mounted auxiliary solar heater

System uses hot-air collectors, no thermal storage, and fan with thermostat switches. At cost of heating efficiency, unit could be manufactured and sold at price allowing immediate entry to market as auxiliary heating system. Its simplicity allows homeowner installation, and maintenance is minimal.

Anthony, K. G.↗