Richard H. Heist

Review of Vapor to Liquid Homogeneous Nucleation Experiments from 1968 to 1992

A comprehensive review of the vapor to liquid homogeneous nucleation experiment literature from 1968 to 1992 is presented. The review identifies and presents in tabular format experimental nucleation data dealing specifically with: (1) critical supersaturation measurements in both unary and binary systems; (2) nucleation rate measurements in both unary and binary systems; (3) photoinduced nucleation experiments; and, (4) ion‐induced nucleation experiments. The data tables identify the substance under investigation; the experimental method used in each investigation; the background gas and, when available, the pressure range of the background gas used in each investigation; a brief summary of the key results of each investigation; and literature references where more detailed information concerning each investigation can be found. The review contains a brief description of the operation of the experimental devices referenced in the tables. The review also contains an assessment of the various experimental ...

Homogeneous nucleation rate measurements. I. Ethanol, n‐propanol, and i‐propanol

Homogeneous nucleation rate measurements have been made on ethanol, n‐propanol, and i‐propanol vapors over a range of temperatures and supersaturations. The Becker–Doring–Zeldovitch nucleation rate expression has been scaled so as to give good agreement with the measured nucleation rates. The same scaling factors are also used to compare calculated critical supersaturations with experimental data obtained from this investigation and a variety of other sources. The agreement is good in all cases. The nucleation rate measurements and the critical supersaturation data from this investigation reveal anomalous behavior for ethanol near 260 K and for n‐propanol near 275 K.

The flow diffusion nucleation chamber: A quantitative tool for nucleation research

We have developed a flow diffusion nucleation chamber designed to quantitatively investigate the nucleation of vapors. The design and operational characteristics of the nucleation chamber are presented and discussed. Critical supersaturation data obtained with this nucleation chamber are compared to literature data obtained using a thermal diffusion cloud chamber. The flow nucleation chamber results accurately reproduce the diffusion cloud chamber data. Results of preliminary measurements of nucleation at ambient pressure in the presence of different background gases are presented. These data suggest that the nature of the background gas may influence nucleation at ambient pressure. These data, while still of a preliminary nature, are consistent with data already published obtained at elevated pressures using a specially designed high pressure cloud chamber also in our laboratory.

Homogeneous nucleation in associated vapors. I. Acetic acid

Homogeneous nucleation measurements on acetic acid vapor are reported. The presence of the relatively stable association clusters tends to stabilize the vapor with regard to homogeneous nucleation. The variation of the critical supersaturation with temperature for acetic acid vapor was found to agree well with the predictions of the Katz–Saltsburg–Reiss theory for nucleation in associated vapors.

Two-dimensional transport and wall effects in the thermal diffusion cloud chamber. I. Analysis and operations criteria

In this paper we present results of a two-dimensional (z,r) treatment of the mass and energy transfer processes that occur during the operation of a thermal diffusion cloud chamber. The location of the wall is considered in solving the mass and energy transport equations, in addition to the vertical distance, z, between the upper and lower plate surfaces. We examine the effect of aspect (diameter to height) ratio on chamber operation; the effects of operation with either a dry or a wet interior chamber wall on temperature, supersaturation, nucleation rate, and total density profiles in the chamber; the effect of overheating the interior of the chamber wall on these conditions within the cloud chamber; and the effects associated with using different density background gases on the operation of the chamber. In a second paper, immediately following, we apply the formalism and the solutions developed in this paper to address the important problem of buoyancy-driven convection that can accompany (seemingly nor...

Homogeneous nucleation in associated vapors. II. Formic and propanoic acids

Homogeneous nucleation measurements have been made on formic and propanoic acids. The temperature dependence of the critical supersaturation was measured and found to agree well with that predicted by the Katz–Saltsburg–Reiss theory for nucleation in associated vapors.

Two-dimensional transport and wall effects in the thermal diffusion cloud chamber. II. Stability of operation

In this paper, the second of a series of two presenting a detailed description of thermal diffusion cloud chamber operation, we address the operational stability of the vapor–gas mixture in a diffusion cloud chamber with respect to density profile extrema and the accompanying possibility of buoyancy-driven convective flow disturbances. We examine conditions for stable operation (no convective flow disturbances) in the central portion of the cloud chamber, as well as conditions necessary for stable operation in the vicinity of the cloud chamber wall. We find that the total density profile in the central portion of the cloud chamber can pass through a density minimum even though the density at the upper plate surface is less than the density at the lower plate surface. This local density profile inversion can result in unstable (convective) behavior that propagates through the cloud chamber. Furthermore, we find that local extrema in the total density profile near the chamber wall can lead to subtle, convec...

Photoinduced nucleation of carbon disulfide

The action of light on undersaturated and supersaturated vapors of carbon disulfide has been investigated using a batch photochemical reactor and a thermal diffusion cloud chamber, respectively. Photoinduced nucleation was observed in each case. In the batch reactor enough sulfur was produced to nucleate and grow a sulfur aerosol. A model for the photoinduced nucleation of supersaturated carbon disulfide is proposed based upon the photochemical production and subsequent nucleation of sulfur. The model predictions compare well with observed nucleation delay time and nucleation rate data. A variation of the model utilizing diradical polymerization instead of nucleation is used to explain photoinduced nucleation results in the literature involving dilute solutions of carbon disulfide in supersaturated ethanol vapor.

NUCLEATION AND GROWTH IN THE DIFFUSION CLOUD CHAMBER. I. OSCILLATORY NUCLEATION

A model is presented describing vapor depletion and latent heat effects accompanying the nucleation and growth of droplets during homogeneous nucleation in a thermal diffusion cloud chamber. The model explains successfully the oscillatory nucleation phenomenon reported earlier by the authors in this Journal.

Homogeneous nucleation in associated vapors. III. Heptanoic, decanoic, and myristic acids

Homogeneous nucleation measurements have been made on heptanoic, decanoic, and myristic acid vapors, all of which exhibit small degrees of hydrogen bond association. The measured temperature dependences of the critical supersaturation are compared with predictions of the Katz–Saltsburg–Reiss theory for nucleation in associated vapors as well as the conventional Becker–Doring–Zeldovitch theory. Heptanoic acid and decanoic acid show good agreement with theory while the myristic acid critical supersaturation measurements are consistently low.