Entropic Aspects of Supercooled Droplet Freezing

Entropic Aspects of Supercooled Droplet Freezing*

We estimate a lower bound on the amount of latent heat liberated by freezing droplets. Based on a physical picture of the freezing process, we arrive at an estimate for the effective latent heat (calculated along a reversible path), suitable for heat budget calculations of glaciating clouds. In addition, we arrive at a quadratic dependence on supercooling for the irreversible contribution to he...

Units of freezing of deep supercooled water in woody xylem.

The low temperature exotherms (LTE) of 1-year-old twigs of Haralson apple (Malus pumila Mill.), shagbark hickory (Carya ovata [Mill.] K. Koch), green ash (Fraxinus pennsylvanica Marsh), honey locust (Gleditsia triacanthos L.), American chestnut (Castanea dentata [Marsh] Borkh.), and red oak (Quercus rubra L.) were determined by differential thermal analysis (DTA). In one type of experiment free...

Factors Influencing Freezing of Supercooled Water in Tender Plants'

Seedlings of beans (Phaseolus vulgaris), corn (Zea mays), and tomatoes (Lycopersicon esculentum) were grown in the greenhouse and then exposed to controlled freezing conditions in a growth chamber. Variables were adjusted to determine the influence of plant water potential, freezing time, and external dew formation on the seedlings' susceptibility to frost injury. Freezing, detected visually an...

Clinical Aspects of Freezing Cold Injury

Size dependence of volume and surface nucleation rates for homogeneous freezing of supercooled water droplets

The relative roles of volume and surface nucleation were investigated for the homogeneous freezing of pure water droplets. Experiments were carried out in a cryogenic laminar aerosol flow tube using supercooled water aerosols with maximum volume densities at radii between 1 and 3 μm. Temperatureand size-dependent values of volumeand surface-based homogeneous nucleation rates between 234.8 and 2...