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Martin, J. R.

Publications and source records attributed to Martin, J. R..

6 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1977

Change in the thermionic work function of semiconductor powders exposed to electromagnetic radiation

The variations of the thermoelectronic work function of titanium dioxide, submitted to an ultraviolet or visible and infrared radiation, in the presence of oxygen, are studied by the vibrating condenser method. It is shown that during the ultraviolet irradiation, a desorption of a first species of oxygen simultaneously occurs with the adsorption of a second species of oxygen and that this phenomenon is found for any structure of TiO2 (anatase or rutile) any texture, oxygen pressure, radiation intensity, and nature of introduced dopes.

Bourasseau, S.↗
NASA NTRS1977

Variation in the thermionic work function of semiconductor powders exposed to electromagnetic radiation

The study of the variation of thermoelectronic work function potential of TiO2 in the presence of isobutane shows that this gas is not adsorbed on this solid, in either the presence or the absence of ultraviolet radiation. These results, as well as those obtained in a previous work, lead to the mechanism of the photo-oxidation of isobutane at room temperature, in which excited atomic oxygen is the active species.

Bourasseau, S.↗
NASA NTRS1974

MSFC Skylab operations support summary

A summary of the actions and problems involved in preparing the Skylab-one vehicle is presented. The subjects discussed are: (1) flight operations support functions and organization, (2) launch operations and booster flight support functions and organization, (3) Skylab launch vehicle support teams, (4) Skylab orbital operations support performance analysis, (5) support manning and procedures, and (6) data support and facilities.

Martin, J. R.↗
NASA NTRS1974

Low-temperature relaxations in amorphous polyolefins

The dynamic mechanical relaxation behavior of two series of amorphous polyolefins, was investigated from 4.2 K to the glass transition. Most of the polymers show a damping maximum or plateau in the 40 to 50 K region. Various mechanisms which have been suggested for cryogenic relaxations in amorphous polymers are considered as they might relate to the polyolefins. Two secondary relaxation processes above 80 K are distinguished. A relaxation at about 160 K (beta) in the second and third member of each series is associated with restricted blackbone motion. This process requires a certain degree of chain flexibility since it is not observed in the first member of each series. A lower temperature process (gamma) is observed in each member of the second series and is attributed to motion of the ethyl side group.

Hiltner, A.↗