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A water-soluble fluorescent-dye aerosol has been used successfully as a meteorological tracer. Because of simple instrumental analysis of field samples and great sensitivity, the technique offers large savings in the cost of tracer studies. The aerosol consists of 2- to 10-micron particles of uranine, generated by pneumatic atomization of a solution. The analysis is based on the fluorescence of a uranine-water solution. The sensitivity of the analysis is 10−10 g (corresponding to a single 5-micron particle) and samples as small as 10−9 g have been analyzed readily. The technique has been applied to a field program involving evaluation over distances up to 8 miles during periods of maximum atmospheric diffusion.

The collection efficiency of glass fiber pads was investigated with a super cooled liquid aerosol. A filter-velocity range of 0.02 to 20 ft./sec. was covered with filter pads having a bulk density ranging from 1 to 10 lb./cu. ft. and a fiber diameter ranging from 1 to 30 μ. For the aerosol employed the results showed a minimum collection efficiency at a velocity of 2 to 5 ft./sec., dependent on fiber size. At the lower velocities, where diffusion is controlling, collection efficiency increased with decreased velocity; at higher velocities, where inertia is controlling, efficiency increased with increased velocity. For purposes of generalization the data were correlated in terms of dimensionless parameters which allow for the combined effects of flow-line interception, inertial interception, and diffusinal deposition. Evaluation of the data in terms of existing theories of deposition indicated nominal agreement with the theory of Langmuir, as modified by Natanson, for diffusional deposition. For inertial deposition the measured collection efficiencies were considerably lower than would be predicted from the theoretical values reported by Langmuir and Blodgett for potential flow around the fibers, presumably because of the viscous-flow (low Reynolds number) conditions that prevailed in this study.

A detailed research plan was established after review and evaluation of current data for simple chemical compounds at high pressure and high temperatures. Apparatus has been designed and is being constructed to recover particles produced by a shock and to minimize the probability of reagglomeration or further collisions. It is hoped that the apparatus can permit a permanent record of the particle distribution if this should be desirable. Theoretical considerations indicate that giving aerosol particles a net unipolar charge will increase the rate at which an aerosol cloud issuing from an apparatus will expand for reasonable aerosol concentration and charge levels. The prime uncertainty rests with the difficulty of achieving the desired charge levels. A laboratory nozzle has been designed and fabricated to permit direct assessment of this concept, using corona for charging. The project on the dissemination of hydrophobic powders has been divided into two tasks. Task 1 is a study of the behavior of solids subjected to shock loading. Task 2 is an investigation to determine whether electrically charged particles of CS agent can be used to improve the effectiveness of the dissemination process.

A technique was developed for measuring electrical mobility distribution of an aerosol and average effective size at each mobility level. An aerosol is passed through a purifier and a narrow mobility channel. The purifier removes charged particles from all but a thin central stream that enters the mobility chamber halfway between electrodes. Particles are deposited on an insulating surface according to their mobility. Total charge distribution on the walls was determined by a special scanning probe; mass distribution was determined by chemical or colorimetric analysis. Tests to determine mobility distribution of a uranine aerosol generated by atomizing and evaporating a dilute water solution yielded fairly consistent results. Results were consistent with expected magnitudes; average particle diameter (volume-to-diameter mean) was 0.8 micron, and particle charge levels ranged from 0.05 to 1 volt/micron specific particle surface gradient. Remaining problem areas are listed and suggestions are given for improving the technique and extending its usefulness.

This bibliography represents a survey of published information relevant to the manner in which electrostatic phenomena might influence dissemination of chemical warfare agents, covering both the open literature and reports of government-sponsored research. Abstracts are included for most of the 1028 references cited.