The recent observation of ultrafine aerosol particles in cirrus clouds has raised the question whether aerosol formation within cirrus clouds is possible, and if so, what mechanisms are involved. We have developed an aerosol parcel model of neutral and charged H2SO4/H2O aerosol processes, including nucleation from the gas phase and loss onto cirrus ice particles. Laboratory thermodynamic data f...

The aim of the present study was to develop an automatic and reliable ice nucleation method by using silver iodide (AgI) as the ice nucleating agent. The effect of the introduction of ice nucleation by AgI was examined by observing the temperature rise due to the release of latent heat of fusion at temperatures where spontaneous freezing did not yet occur. AgI in distilled water was loaded into...

New measurements of water diffusion in secondary organic aerosol (SOA) material produced by oxidation of α-pinene and in a number of organic/inorganic model mixtures (3-methylbutane-1,2,3-tricarboxylic acid (3MBTCA), levoglucosan, levoglucosan/NH4HSO4, raffinose) are presented. These indicate that water diffusion coefficients are determined by several properties of the aerosol substance and can...

Temperature-dependent volume nucleation rate coefficients for supercooled water droplets, JV (T ), are derived from infrared extinction measurements in a cryogenic laminar aerosol flow tube using a microphysical model. The model inverts water and ice aerosol size distributions retrieved from experimental extinction spectra by considering the evolution of a measured initial droplet distribution ...

Certain natural organisms use micro-patterned surface chemistry, or icenucleating species, to control water condensation and ice nucleation for survival under extreme conditions. As an analogy to these biological approaches, it is shown that functionalized, hydrophilic polymers and particles deposited on the tips of superhydrophobic posts induce precise topographical control over water condensa...

The probability of homogeneous ice nucleation under a set of ambient conditions can be described by nucleation rates using the theoretical framework of Classical Nucleation Theory (CNT). This framework consists of kinetic and thermodynamic parameters, of which three are not well-defined (namely the interfacial tension between ice and water, the activation energy and the prefactor), so that any ...

Antifreeze proteins (AFPs), occurring in some polar animals, plants, fungi, and other organisms, are capable of inhibiting ice freezing at subzero temperatures. The application of AFPs can be found in medicine and industry where low temperature storage is required and ice crystallization is damaging. This includes improved protection of blood platelets and human organs at low temperature, incre...

Nanoparticles of iron oxide (crystalline and amorphous), silicon oxide and magnesium oxide were investigated for their propensity to nucleate ice over the temperature range 180–250 K, using the AIDA chamber in Karlsruhe, Germany. All samples were observed to initiate ice formation via the deposition mode at threshold ice super-saturations (RHithresh) ranging from 105% to 140% for temperatures b...

The preliminary finding that nonprotein additions to the protein product of the ice-nucleating gene of Pseudomonas syringae or Erwinia herbicola are essential for ice nucleation at the warmest temperatures has led to experiments aimed at identifying possible linkages between the ice protein and the other components. It appears that the protein is coupled to various sugars through N- and O-glyca...