a The purpose of this study was to evaluate the inhalation hazard to which aircraft crews would be exposed on passing through an atomicbomb cloud and to determine the degree of the inhalation hazard relative to the external radiation hazard. The sample for the cascade impactor was obtained from the cabinpressurizing system in the drone F-80 aircraft through the standpipe on the right of the pilot's seat in the cockpit. Three cascade-impactor samples were collected in the cloud result- ing from two air-burst detonations. after the detonations. Samples were collected from 2 to 7 min The particles collected ranged in average diameter from less than 0.1 » up to 4.2 »; and over 95% of the activity present was associated with particles less than 0.2 »p in diameter. The total individual internal-radiation dose resulting from the inhalation of fission products during the cloud passage was calculated, using certain basic assumptions, and found to be 1.9 mr. This internal dose is negligible compared with the integrated, external gamma dose of 30 r. A preliminary report of this work appeared as CRLR 188. CRLR - 300 . - AN EVALUATION OF SOME LIQUID ADHESIVE KW AGENTS CONTAINING VARIED PERCENTAGES OF ZIRCONIUM-NIOBIUM OXIDE. Robert J. Smith, Seymour Tarras, and Malcolm G. Gordon, 4 February 1954. SECRET-RESTRICTED DATA , The objectives of this investigation were: (1) to determine the adhesive properties toward asphalt and concrete of mixtures of silicate in water, polystyrene in ethylene dichloride, and polymethyl methacrylate (lucite) in ethylene dichloride, each containing from 3% to 40% of radio- active zirconium-niobium oxide agent; (2) to study the effects of various drop-sizes on retention (resistance to decontamination) of the three mixtures; and (3) to determine the drying time of the adhesive agents at various temperatures. The asphalt and concrete test-pieces were contaminated with drops released from glass dropping-tubes of different orifice size and at various heights. The samples were counted, decontaminated by a wet-~-brushing technique and counted again. Of the silicate~agent mixtures, only those containing less than 10% of agent were retained satisfactorily on concrete; the retention of all such was unsatisfactory on asphalt. The lucite-agent and polystyrene-agent mixtures were retained on asphalt when as much as 40% solid agent was used, and on concrete with up to 30% solid agent. silicate solutions dried slowly at room temperature and froze without drying below 32°F. The lucite and polystyrene solutions dried quickly at room temperature and only slightly slower at 30°F. and shriveled after a 6-hr exposure. RES! The yA quam 38 ‘They both froze at O°F a OF WNRC =D