Accession Number : AD0765900

Title :   Application of the Method of Laplace to the Measurement of Homogeneous Nucleation Rates,

Corporate Author : BROWN UNIV PROVIDENCE R I DEPT OF ENGINEERING

Personal Author(s) : Dobbins,Richard A. ; Eklund,Thor I.

Report Date : JUL 1973

Pagination or Media Count : 47

Abstract : The application of the method of Laplace to the evaluation of the nucleation integral leads to the formulation of an explicit relationship for the nucleation pulse duration applicable in a Wilson cloud chamber. The nucleation pulse duration is primarily a function of absolute temperature and certain of its derivatives evaluated at the instant of peak nucleation rate when temperature is a minimum. The mathematical technique demonstrates the sudden appearance of a droplet cloud in any type of condensation experiment. Methods of measuring temperature using dual-probe, hot wire anemometry are discussed. Preliminary measurements in the Wilson cloud chamber confirm that temperature has a minimum value when nucleation occurs and is asymmetric about its minimum. Sample data reduction for the asymmetric temperature history is given. An error analysis is included. The technique possesses the potential of providing definitive measurements not only of nucleation pulse duration but also of nucleation rate and an experimental value of the highly disputed pre-exponential factor. (Author)

Descriptors :   (*NUCLEATION, *POTENTIAL THEORY), CLOUD CHAMBERS, HEAT TRANSFER, ANEMOMETERS, PARTIAL DIFFERENTIAL EQUATIONS, STATISTICAL MECHANICS, NUMERICAL INTEGRATION

Subject Categories : Physical Chemistry
      Theoretical Mathematics

Distribution Statement : APPROVED FOR PUBLIC RELEASE