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Efficiency of Scavenging Devices in Determining Falloug. Progress Report No. 6 March 15 to July 31, 1957

Description: A fall-out sample collector was designed and tested for use in collecting samples at the soil surface. The sampler consists of artificial grass and a stainless steel pot. Results are included from preliminary studies on the scavenging properties of artificial grass. The effects of relative humidity, rain, and wind velocity on the efficiency of scavenging devices were investigated. A comparison was made of Sr/sup 90/ fall-out data from samples collected on gummed film and surface soil samples from various locations. Preliminary experiments were performed for the evaluation of devices used in determining air concentration of radioactive fall-out or other particulate matter. (For preceding period see AECU-3435.) (C.H.)
Date: September 23, 1957
Creator: Rosinski, J.
Partner: UNT Libraries Government Documents Department

Scavenging of Particulate Matter in Connection With Nuclear-Powered Ships. Final Scientific Report

Description: The work carried out over a 2 1/2-yr period on the scavenging of radioactive particles which might be released by the reactor system of a nuclear- powered ship is summarized. Two types of dispersions were considered: aerosols and hydrosols. Radioactive aerosols were scavenged by heterogeneous coagulation with solid and liquid aerosols produced within the radioactive aerosol cloud. Liquid or highly hygroscopic particles, which can be classified as solid particles with liquld films on their surfaces, were found to be the most effective scavengers. A system of fine water spray and hydrolysis products of silicon tetrafluoride was found to be suitable for field application. Scavenging of radioactive cations, anions, and colloids of corrosion and fission products was studied in substitute ocean water, natural ocean water, and natural harbor water. A scavenging system composed of KMnO/sub 4/ and ferrous salts successfully removed most of the radioisotopes. Fe(OH)/sub 3/--MnO/sub 2/ hydrate adsorbed and absorbed radioactive species, thus transferring them from a liquid to a solid phase. Addition of Floc 111 to the system improved sedimentation. The KMnO/sub 4/-FeSO/sub 4/-Floc 111 system was found to bs suitable for field application. (auth)
Date: July 29, 1960
Creator: Rosinski, J.
Partner: UNT Libraries Government Documents Department

Preliminary Studies of Scavenging Systems Related to Radioactive Fallout. Letter Report No. 10 for October 1 to December 1, 1959

Description: Progress is reported in the development of scavenging systems for the collection of fall-out. Data are included from tests of two cyclone separators for the collection of air samples. Results are included from laboratory studies on the scavenging of aerosol particles by evaporating and condensing water droplets. (C.H.)
Date: December 18, 1959
Creator: Stockham, J. & Rosinski, J.
Partner: UNT Libraries Government Documents Department

Preliminary Studies of Scavenging Systems Related to Radiactive Fallout. Summary Report

Description: A program consisting of two related phases is described Ia Phase I, a study was made to find the relationship between the amount and nature of radioactivity, particle size distribution, and weight of particulate matter present in the lower troposphere. Emphasis was placed on the distribu tion of strontium-90 and total beta activity. Results of a limited number of analyses indicate that strontium-90 and total beta activity is associated primarily with particles below approximately 0.1 micron diameter. Phase II consisted of experimental studies on scavenging of solid particulate matter by water droplets. It was found that water vapor gradient around a condensing droplet promotes scavenging of particles of 1.3 micron and 0.3 micron diameters. The effect of water vapor gradient around an evaporating droplet is not well defined. (auth)
Date: April 29, 1960
Creator: Rosinski, J. & Stockham, J.
Partner: UNT Libraries Government Documents Department

Preliminary Studies of Scavenging Systems Related to Radioactive Fallout. Letter Report No. 8 Covering Period June 1 to August 1, 1959

Description: Progress is reported on the separation of airborne particles into size fractions for radioactive analysis. Laboratory studies of scavenging systems were conducted using a latex suspension diluted 1 to 500 parts with polystyrene then atomized with a Lauterbach generator. Tests were conducted for the collection of polystyrene particles by an evaporating water droplet. The results from these tests are included. The size distributions of particles obtained from atomizing latex and 1% gelatin suspensions are tabulated. The latex suspensions were diluted 1:500, 1:100, and 1:10. Future laboratory studies are to be directed toward elimination of charged aerosol particles and the use of radiochemical techniques for determining the amount of material collected by a water droplet. (For preceding period see ARF-3127-7.) (B.O.G.)
Date: August 20, 1959
Creator: Stockham, J. & Rosinski, J.
Partner: UNT Libraries Government Documents Department

Preliminary Studies of Scavenging Systems Related to Radioactive Fallout. Summary Report

Description: Preliminary studies were made of the relationship between the size of particles suspended in the lower atmosphere and the amount and nature of radionuclides they contain. Emphasis was placed on the distribution of strontium90. From a limited number of analyses, it was found that strontium-90 is associated primarily with particles below 0.1 micron in diameter. Preliminary studies were made of scavenging of particles by liquid water droplets. Studies are included of sticking probability and the effects of Brownian motion and water vapor diffusion. It was found that electrostatic effects are of primary importance for 1.9-micron (mean volume diameter) particles. Brownian motion and water vapor diffusion did not contribute to the scavenging. These results are based on known and new equations derived for various scavenging conditions. (auth)
Date: April 30, 1959
Creator: Rosinski, J. & Stockham, J.
Partner: UNT Libraries Government Documents Department

Preliminary Studies of Scavenging Systems Related to Radioactive Fallout. Letter Report No. 7 Covering Period April 1 to May 31, 1959

Description: Progress is reported on the development of a cyclone which will remove particles larger than 8 microns. A method is proposed for a more efficient separation of particles by increasing the number of size separation filters in the sampling train. Preliminary tests with submicron polystyrene particles are being conducted. Numerous methods have been tried for counting the particles in a water droplet of the polystyrene aerosol. The criteria for a satisfactory method of counting particles are discussed. A proposed method to accomplish this is to use carbon-14 labeled polystyrene hydrosols. (For preceding period see ARF-3127-6.) (B.O.G.)
Date: June 15, 1959
Creator: Stockham, J. D. & Rosinski, J.
Partner: UNT Libraries Government Documents Department