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<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />11 <br /> <br />diameter in an equilibrium droplet only 1" of the AgI will be in <br /> <br />solution. Davis (1972) examined the effect small particle size has on <br /> <br />the solubility of AgI in AgI-HaI-water systems, Small particle size is <br /> <br />known to enhance the solubilty of various salts (Dundon and Mack. 1923 <br /> <br />and Pruppacher and Klett. 1978. p. 160). For a Agl partiole of O.05~m <br /> <br />diameter (a realistic size tor IIOst acetone generf.~.Q11....bW"~l1&a <br />~-------<--'~._- -, ~>_.~~,-~--- . '--'--~""'--~~--~_."" ~--- -. -'- " <br /> <br />2Ag1"HaI soly~~~n) in water alone. solubility is inoreased about 1.. due <br />~---- <br /> <br />to size alone. In a saturated solution of NaI. approxiJlllltely 30ft of the <br />AgI in the particle dissolves. <br /> <br />The fact that AgI-NaI aerosol partioles .~I"t!~ygrosQOp~c was <br />__---~'~~...----~-O___~..._ _ ,". . . _, _""'_" <br /> <br />established by Mossop and Tuck-Lee (1968). Eleotron micrographs of <br /> <br />particles with mean diameter of O.085~m show growth of all the particles <br /> <br />between 40 and 80ft relative humidity. These ~.~icles are abou~~~n <br /> <br />order of magnitude more effective as condensation nuclei than are pure <br />-~ ~ ~ ~ <br />------~-----=- <br /> <br />AgI particles (Mos~op._"!968~. <br />.~,,~~,-,._-,:.-_.~.-,<- <br /> <br />2.1.3 General Ioe Nucleation Characteristics of AgI-NaI Aerosol <br /> <br />Yield ot ice nucleation has been reterred to as effeotivity or <br /> <br />activity and has been measured as the number of ice crystals per gram of <br /> <br />AgI produced by the generator used. Effectivity of ice nucleation by <br /> <br />aerosol particles produced by the combustion ot AgI. Hal. and acetone <br /> <br />has been studied using a variety of techniques (Smith and Hetternan, <br /> <br />1954. Edwards and Evans. 1960. Warburton and Heffernan, 1964. Grant and <br /> <br /> <br />Steele. 1966. Davis and Steele, 1968. Mossop. 1968. Mossop and <br /> <br />Jayaweera, 1969. Donnan, et al.. 1970. St.-Amand. et al.. 1971. Blair. <br /> <br />et al.. 1973. and Garvey, 1975). Reported values of yield or <br /> <br />effectivity are strongly dependent on temperature. chemical composition <br /> <br />of the aerosol particles tested. type of generator. and device used for <br />