CLOUD CHAMBER TESTS OF GENERATORS USING ACETONE SOLUTIONS OF AGI - NAI - KI AND AGI - NH/SUB 4/I.

Abstract

THE ICE-NUCLEATING PROPERTIES OF CLOUD SEEDING MATERIALS PRODUCED BY BURNING ACETONE SOLUTIONS OF AGI - NAI - AGI - KI AND AGI - NH/SUB 4/I HAVE BEEN TESTED IN A WIND-TUNNEL CLOUD-CHAMBER TEST FACILITY.THE AGI AEROSOL PRODUCED FROM 5 PER CENT AGI-NH/SUB 4/I SOLUTIONS YIELDS NUCLEI ACTIVE AT TEMPERATURES AS WARM AS -4C AND SHOWS AN EFFICIENCY OF 10/SUP 12/ NUCLEI PER GM.AGI AT -5C.AEROSOLS FROM SIMILAR SOLUTIONS OF AGI-KI AND AGI-NAI PRODUCE NO ICE CRYSTALS AT TEMPERATURES WARMER THAN -6.5 AND -8C, RESPECTIVELY.TEMPERATURES OF -7.5 AND -9.C ARE REQUIRED TO OBTAIN EFFICIENCIES OF 10/SUP 12/ NUCLEI PER GM FOR THESE TWO LATTER SOLUTIONS.THE GREATER ICE NUCLEATING ABILITY OF THE NH/SUB 4/I SOLUTION AT HIGH TEMPERATURES IS ATTRIBUTED TENTATIVELY TO THE PRODUCTION OF RELATIVELY PURE AGI CRYSTALS RATHER THAN TO INCREASED PARTICLE SIZE BUT MAY ALSO RESULT FROM MINOR NH/SUB 4/I CONTAMINATION.CALCULATIONS OF THE DROPLET-AEROSOL PARTICLE COLLISION RATES SHOW THAT CONTACT NUCLEATION COULD EXPLAIN ALL ICE FORMATION OBSERVED AT HIGHER CHAMBER TEMPERATURES, ALTHOUGH OTHER PROCESSES MAY OCCUR SIMULTANEOUSLY.ON THE OTHER HAND, THE CALCULATIONS ALSO SHOW THAT DIRECT ICE DEPOSITION OR CONDENSATION FREEZING IS LIKELY THE DOMINANT MECHANISM BELOW -12C.THE IMPLICATIONS OF THE LABORATORY RESULTS FOR FIELD APPLICATIONS ARE DISCUSSED BRIEFLY.IT IS CONCULDED THAT THE AGI-NH/SUB 4/I SYSTEM OFFERS SU FFICIENT ADVANTAGES TO JUSTIFY ITS ADOPTION IN FIELD PROJECTS.(A)