Engineering topics

Bethke, G. W.

Publications and source records attributed to Bethke, G. W..

7 records

NASA NTRS1981

Performance and design of the ultraviolet spectrometer and polarimeter on the solar maximum mission

The instrument observes spectral line intensity, Doppler motions, and polarization parameters. First Dopplergrams of the sun showing mass motion of prominences have been obtained. The instrument consists of a telescope, a spectrometer, a polarimeter, and five detectors. Spectral range extends from 1150 to 3600 Angstroms. The telescope is an alphanatic Gregorian capable of scanning a 256 x 256 arcsecond raster. The spectrometer is an Ebert-Fastie mount with exchangeable slits for intensity measurements and spectroscopy. Detectors are photomultipliers operating in the pulse-counting mode.

Sterk, A. A.↗

NASA NTRS1977

Heterogeneous chemical reactions: Preparation of monodisperse latexes

It is demonstrated that a photoinitiated emulsion polymerization can be carried out to a significant conversion in a SPAR rocket prototype polymerization vessel within the six minutes allowed for the experiment. The percentage of conversion was determined by both dilatometry and gravimetric methods with good agreement. The experimental results lead to the following conclusions: (1) emulsion polymerizations can be carried out to conversions as high as 75%, using a stable micellized styrene-SLS system plus photoinitiator; (2) dilatometry can be used to accurately determine both the rate and conversion of polymerization; (3) thermal expansion due to the light source and heat of reaction is small and can be corrected for if necessary; (4) although seeded emulsion polymerizations are unfavorable in photoinitiation, as opposed to chemical initiation, polymerizations can be carried out to at least 15% conversion using 7940A seed particles, with 0.05% solids; and (5) photoinitiation should be used to initiate polymerization in the SPAR rocket experiments because of the mechanical simplicity of the experiment.

Vanderhoff, J. W.↗

NASA NTRS1967