Particulate emissions from energy systems

General models of aerosol dynamics, originally developed to simulate atmospheric aerosol behavior, have been extended for application to combustion and other high temperature processes. These models are now being used to study the fate of ash vapors in conventional pulverized-coal combustion. Field measurements have shown that the vapors condense preferentially on the surfaces of the smaller ash particles. Previous simplified calculations have suggested that large numbers of very small particles may also be formed by the condensation of these vapors. The new, exact calculations will be used to explore the relative importance of new particle formation and condensation on existing particles, the size distributions of the particles produced under various combustion conditions, and the distribution of chemical composition with respect to particle size

The Insects. Peter Farb and the editors of Life. New York: Time Inc., 1962. 192 pp. $4.00.

Excerpt: It is a pleasant surprise to find a book that can effectively communicate much information about insects to the lay public, amateur entomologist, and professional entomologist alike. In straight-forward language the author gives genuine insight into the morphology, physiology, behavior, evolution, and adaptation of insects. These areas are not treated as unrelated topics but are skillfully blended into a meaningful whole. The text is supported liberally with pertinent facts, clear drawings, and many photographs of remarkable quality. The lack of obvious mistakes indicates that editing has been carried out carefully

A thermodynamically consistent kinetic framework for binary nucleation

The traditional theory for binary homogeneous nucleation follows the classical derivation of the nucleation rate in the supposition of a hypothetical constrained-equilibrium distribution in the calculation of the cluster evaporation rate. This model enables calculation of the nucleation rate, but requires evaluation of the cluster distribution and cluster properties for an unstable equilibrium with supersaturated vapor. An alternate derivation of the classical homomolecular nucleation rate eliminated the need for this nonphysical approximation by calculating the evaporative flux at full thermodynamic equilibrium. The present paper develops that approach for binary nucleation; the framework is readily extended to ternary nucleation. In this analysis, the evaporative flux is evaluated by applying mass balance at full thermodynamic equilibrium of the system under study. This approach eliminates both the need for evaluating cluster properties in an unstable constrained-equilibrium state and ambiguity in the normalization constant required in the nucleation-rate expression. Moreover, it naturally spans the entire composition range between the two pure monomers. The cluster fluxes derived using this new model are similar in form to those of classical derivations, so previously developed methods for evaluation of the net nucleation rate can be applied directly to the new formulation

Thamnophis brachystoma

Number of Pages: 2Integrative BiologyGeological Science

Taste-Masking: Function of Exaggerated Prandial Drinking in Desalivate Mice

Taste thresholds for the bitter compound sucrose octaacetate (SOA) were elevated by desalivation in mice. Thresholds were determined for control and experimental animals both before and after ligation of all salivary ducts. There was a significant increase in SOA thresholds in the desalivate mice, and the pre- to post-operative differences in threshold between the control and experimental groups were significant. The altered response to SOA by desalivate mice is shown to be due to the assumption of a prandial pattern of drinking as a result of desalivation. This conclusion is based on experiments with wet mash which failed to show any differences in threshold between the same control and desalivate mice that demonstrated a significant difference when tested on fluids and dry pellets