UNCLASSIFIED VI. (S-RD) CHEMICAL WARFARE LABORATORIES REPORTS. ( CWLR) (U) Construction and calibration of a thermistor disc calorimeter to measure thermal radiation for the TRAC studies are reported. Since this instrument is to be used at atomic weapons field tests it must be rugged, gamma insensitive, have a reception angle of 2x steradians, and be easily transported and installed. This instrument was tested successfully at one nuclear detonation at Operation TEAPOT under severe field conditions. The instrument performed satisfactorily. CWLR - 2039 - i ‘ SUBSIDENCE OF A COLUMN OF AIRBORNE PARTICLES (U). Martin 0. Harwit, 27 June 1956. UNCLASSIFIED, Technical Report (U) A theoretical investigation of the mechanism of the subsidence of dense suspensions is reported. The aggregate of particles forming the suspension was found theoretically to subside through the surrounding atmosphere, behaving as though it were a fluid of the same density as the suspension. The subsidence velocity ef such a fluid is much larger than the terminal velocities of the individual falling particles. A method is outlined for calculating subsidence times and subsidence velocities for a given situstion. CWLR - 20L6 - DEPOSITION OF AIRBORNE PARTICLES ON A LARGE HEATED SURFACE (vu). Martin Harwit, 17 August 1956. UNCLASSIFIED TECHNICAL REPORT (U) Zhe effect of a large heated surface on the deposition pattern from @ pol“uted atmosphere is studied. It is concluded that the use of heat to avert the deposition of particulate matter 20u to 300u in size is not practical. UNCLASSIFIED WHE t