Aerosol conditioning, definition

This introductory chapter addresses the concept of the aerosol condition of matter first by explaining how it arose and then by delineating the physical questions which are common to all such systems. Section 1.1 reviews possible definitions of "aerosol" and Sect.1.2 discusses the division among the component studies of aerosol physics which is followed in these volumes. The discussion of aerosol microphysics in Sect.1.2.2 establishes its relationship to the conventional investigations of basic physics. To be of value both to the basic scientist seeking the context of his work in other natural sciences and in technology and conversely to the engineer or natural scientist curious of how his domain of interest is related to aerosol microphysics, Sect.1,3 briefly discusses examples of where aerosols arise. 

Our data set definitely shows high variability for any simple relationship between local wind speed and sea-salt aerosol concentration. This occurrence may only reflect unique meteorological conditions during one summer season because frequency plots of our wind-speed data show values outside the ranges of the expected seasonal averages prevailing in this region of the South Atlantic (21). The data set was also filtered (Table II, Case XII) to exclude samples collected at wind speeds less than 8 m/s. This trial exercise results in an increase in the slope when compared to Case I, but the correlation coefficient is unexpectedly lower. However, this manipulation does not represent true winter conditions because the temperature difference between the sea and the air would be different in the winter than it was for our February cruise. 

Conventional animal developmental studies in rats and rabbits exposed to CS aerosols at a concentration of around 10 mg m-3 for 5 min have shown that CS is not embryotoxic and teratogenic in rats and rabbits (Upshall, 1973). However, the exposure conditions, meant to simulate riot control situations, do not allow for definitive... 

In this section we will discuss the chemical potentials of species in the gas, aqueous, and aerosol phases. In thermodynamics it is convenient to set up model systems to which the behavior of ideal systems approximates under limiting conditions. The important models for atmospheric chemistry are the ideal gas and the ideal solution. We will define these ideal systems using the chemical potentials and then discuss other definitions. 

A rapid sampling method for direct aerosol analysis using FD-mass spectrometer has been described . In a predominantly inorganic aerosol three alkali metal cations and a number of cluster ions of intact salts have been identified under the conditions of high mass resolution (R 15,000, 10 per cent valley definition) using photographic registration. 

Radionuclides are released to the containment as gases and as aerosol particles by a variety of processes during severe accidents. Modem, mechanistic analyses of these radionuclide releases and the subsequent behaviour of aerosols and vapours under reactor accident conditions strive to be realistic. This realistic approach contrasts with the deliberate attempt to be conservative (which may not have been successful) in the definition of radionuclide behaviour for the design of nuclear power plant safety systems. A discussion of the various radionuclide release processes during severe reactor accidents is presented in Chapter II. Of primary interest in these discussions of release is the potential magnitude of radionuclide release and the radionuclides of most concern. Factors that most affect radionuclide release but can also be affected by accident management measures are discussed. 

Less straightforward is the definition of the source term the initial conditions of cloud mass, temperature, concentration, and dimensions (height, width). This is a function of the discharge type (spill or pressurized jet), the rate and duration (or mass if a puff) of release, temperamre before and after any flash, the flash fraction, aerosol/fog formation, and initial dilution. Some models include source term models which may not be apparent to the user. 

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