SPECTRAL EMISSIVITY MEASUREMENTS OF ABLATING PHENOLIC GRAPHITE

Surface spectral radiance of ablating phenolic graphite was measured in wavelength region between 0. 3 and 10. 5 U; material was heated to its ablation temperature in arc-heated subsonic air stream having equilibrium temperature of approximately 5000 K; by comparing measured surface for 2500 K blackbody, spectral emissivity varies from 0. 87 in visible spectrum to 0. 62 in infrared; spectral emissivity data show that ablating phenolic graphite radiates nearly as graybody in visible and in wavelength region of 3 to 10. 5 U. 70 COAL MINES AND MINING Rock Pressure Evaluation, with help of photoelastic models, or rock pressure developing in coal mine workings, located underneath limits of protective pillars, (Der Zusatzdruck beim Unterbauen von Kohlenfesten und Abbaukanten in spannungsoptischen Modellversuchen); M. KLOECKNER, H. JACOBI; Glueckauf-Forschungshefte v 29 n 6 Dec 1968 5- 9; Behaviorn ht analogies may be helpful in early identification of zones of high rock pressure, thus prone to rock bursts or roof caving, so that preventive measures could be taken early; models can also be helpful in choosing methods of mining that would eliminate zones of high rock /COAL MINES AND MINING, Accident Prevention/ ION EXCHANGERS Low-temperature desorption by water vapor of substances adsorbed on zeolites; . A. RYBKINA, A. AEV, T. GRBEDON LS/ L. A. RYBKINA, A. N. SHIRYAEV, T. G. PLACHENOV; Zhurnal Prikladnoi Khimii v 41 n 8 Aug 1968 p 1771-8. See also English translation in J Applied Chem of USSR v 41 n 8 Aug 1968 p 1670-5; Results of study of desorption of carbon dioxide, benzene, and normal alkanes adsorbed on zeolite showed that adsorbed components h use of water vapor as desorbent; adsorption properties of zeolite can be restored by desorption of water vapor with aid of products formed by combustion of gaseous fuel.