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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 667 records · Page 37
All sourcesNASA NTRSDOE OSTI
NASA NTRS1965

On dielectric lenses

Dielectric lens for correction of curved field lines in electromagnetic wave propagation

ELECTROMAGNETIC PROPAGATION↗
NASA NTRS1975

Collection and concentration of solar energy using Fresnel type lenses

The efficiency of collecting solar energy using a Fresnel type lens was measured for two different collectors. A flow collector utilizes the temperature difference and heat capacity in water measurements to determine the amount of absorbed energy retained from sun rays passing through the Fresnel lens. A static collector is a hollow copper box filled with vegetable heating oil for absorption of focused solar radiation.

Wilson, R. F.↗
NASA NTRS1976

Wide angle lenses with aspheric correcting surfaces

Refracting elements having aspheric correcting surfaces near the center of curvature are analyzed. As in the case of the Schmidt reflector, such systems can have a wide aperture and a wide field of view; in addition, they are free from obstructing surfaces. Being uncorrected for dispersion, however, the refracting systems are restricted to nearly monochromatic radiation. Typical forms of the correcting surfaces have been determined, both by third order theory and by numerical integration of exact equations.

Jones, R. T.↗
NASA NTRS1976

Effects of edge-rounding on geodesic lenses

A method that eliminates the need for a mathematical model is described for measuring the absolute light intensity radiated from volume chemiluminescent and fluorescent sources. This technique applies to a uniform cylindrical luminous volume, which is the geometry most often practical for the study of flowing chemiluminescent and fluorescent fluids. In this method, the necessary integration over a luminous volume is carried out experimentally, using a calibrated piston source that has as its head a disk of uniform luminosity. The relatively small total error in absolute light intensity measurements with the piston source technique represents a significant improvement over competing comparison methods. The construction of a piston source to fit the cross section of a particular cylindrical volume is straightforward, and its calibration against a standard source can be readily made while exercising normal precautions.

Wood, V. E.↗