Junge distribution

A value of p -4 C Junge" distribution) provides a useful approximation for many continental aerosol distributions over the size range 0.2 < dp < 10 The power law form also simplifies Mie theory calculations oflight scattering (Chapter 5). Small deviations from the power law in the range around I to 3 /rm lead to the bimodal volume distributions of Fig. 13.1. 

The Power-Law Distribution A variety of other mathematical functions have been proposed for the description of atmospheric aerosol distributions. The power law, or Junge, distribution was one of the first used in atmospheric science (Prup-pacher and Klett 1980),... 

Very early on, Aitken (1923) showed that most particles in the atmosphere are smaller than 0.1 pm diameter and that their concentrations vary from some hundreds per cm over the ocean to millions per cm in urban areas. Junge (1955,1963,1972) measured the atmospheric aerosol number size distribution and concentration in urban and non-urban areas as functions of altitude and site. He established the standard form for plotting size distribution data log of AN/ADp versus logD, where N = number and Dp = particle diameter. He observed that this plot was a straight line that could be described by the equation AN/ADp = AD, where A and k were constants. He also noted that in the range from 0.1 to 10.0 pm particle diameter, k was approximately equal to 4.0. This distribution mode was widely known as the Junge distribution or the power law distribution. 

Friedlander (1961) later showed that by balancing aerosol source and removal rates a portion of the resultant theoretical number distribution steady state could be fitted reasonably well by the Junge distribution. Clark and Whitby (1967), by fitting the Junge distribution to 52 at-... 

The more or less straight-line portion of the distribution between 0.1 and 10 )im can be represented by an inverse power law distribution (the Junge distribution). 

The oligomer distribution is highly dependent on the method of isolation of the oligomers (TLC, Soxhlet or dissolution/precipitation). Jung and Lee [513] have determined a dimer of 2-phenylbenzoxazole in a polyester resin by means of TLC. A comparative study of the separation of styrene oligomers (up to dodecamers) by TLC and OPLC has appeared [514]. 

Raff, Jeffrey. Jung and the alchemical imagination. York Beach (ME) Nicolas-Hays distributed to the trade by Samuel Weiser, 2000. xxvi, 277 p. ISBN 0-89254-045-1... 

Jung, T., Subramanian, R.V. and Manoranjan, V.S. (1993). Prediction of fiber strength at the critical length A simulation theory and experimental verification for bimodally distributed carbon fiber strength. J. Mater. Sci. 28, 4489-4496. 

SVOCs may be simultaneously present in meaningful amounts in the gas phase and on the surface of airborne particles. Therefore it is important to sample both the gas phase and the partide phase. This distribution between the gas phase and particles is known as partitioning and may roughly be illustrated by Junge s equation (Junge, 1977) derived on the basis of adsorption theory ... 

Methods for Estimating the Particle/Gas Distribution in Ambient Air 10.3.1 Junge-Pankow Adsorption Model... 

Despite many years of interest in the phase distribution of POPs, few predictive models are available. A Langmuir-type relationship, which Junge (1977) first proposed and Pankow (1987) later reviewed and critically evaluated, is the most popular model for estimating adsorption onto aerosols. The Junge-Pankow equation relates the fraction of particulate POPs (c >) to the saturation liquid-phase vapor pressure of the compound ( P Pa) and the surface area of particles per unit volume of air (8, cm2 aerosol / cm3 air). 

The 9-parameter is also subject to uncertainty. It is likely that Whitby s (1978) estimates of 9 (Table 10.1) do not reflect the true surface area distribution, since they were based on the average size spectrum of aerosols and assumed spherical particles. Adsorption/desorption kinetics (Kamens et al., 1995 Rounds and Pankow, 1990,1993) and relative humidity (Goss and Eisenreich, 1997 Lee and Tsai, 1994 Pankow et al., 1993 Storey et al., 1995 Thibodeaux et al., 1991) influence the adsorption of POPs onto aerosols, and the Junge-Pankow model does not take these factors into account. 

Fig. 1.9. Size distributions of condensation nuclei. A, Junge s number distribution B, Junge s mass distribution C, activity distribution of newly attached decay products.

Table 1.9 shows typical values of the rate coefficients for unattached 218Po in dwellings. The nucleus concentration is taken as 1.7 x 1010 nT3 with a Junge-type distribution of dp, as described above (section 1.12). 

Junge, C.E. (1964) The modification of aerosol size distribution in the atmosphere. Final Technical Report, Contract-Da 91-591-EVC 2979. European Research Office, US Army (From Warneck, 1989). 

J. Rossi, A.E. Jung, D. Ritchie, J.W. Lindsey, A.E. Nordholm, Tissue distribution, metabolism, and clearance of the convulsant trimethylol propane phosphate in rats, Drug Metabolism and Disposal, 26, 1058-1062, 1998. 

Roggenkamp HG, Jung F, Kiesewetter H (1983) Em Gerat zur elektrischen Messung der Verformbarkeit von Erythro-cyten. A device for the electrical measurement of the de-formability of red blood cells. Biomed Techn 28 100-104 Seiffge D, Behr S (1986) Passage time of red blood cells in the SER their distribution and influences of various extrinsic and intrinsic factors. Clin Hemorheol 6 151-164... 

Colom R, Jung RE, Haier RJ. 2006. Distributed brain sites for the g-factor of intelligence. Neuroimage 31 1359-1365. 

Junge (128) estimated that tropospheric aerosols had a lifetime of approximately 10 days, although the rate of removal decreased rapidly with increasing altitude. On the basis of the distribution of fission products,... 

The distribution of water vapor in the troposphere is controlled by general climatic conditions rather than by atmospheric photochemistry. On the basis of rainfall measurements, Junge (128) estimated a 10-day average residence time for water vapor. 

Unfortunately as Kellogg et al., Robinson and Robbins, Junge, and Eriksson have all pointed out, most of the atmospheric measurements have been made in polluted areas of the United States and Europe, so not much is known about normal background concentrations of sulfur compounds and their global distribution. Therefore the atmospheric cycle is somewhat speculative, as are also estimates of individual sinks, sources, and concentrations. 

Swinnerton, Linnebom and Cheek (239) and Seiler and Junge (226) reported that the ocean, which they found to be supersaturated with CO, might be an important source. It is also possible that the oxidation of nonmethane hydrocarbons, particularly those whose production occurs over land, may be another huge source. Since, as we will see later, methane is thought to have a uniform distribution throughout the troposphere, some... 

Determining the size distribution and composition of the stratospheric aerosols and their evolution have been among the main questions posed since the discovery of the layer (Junge et d., 1960). The steady state... 

Baumgartner, E. Hofmann, J. Jung, R.H. Moors, R. ABS Molding Materials having a Bimodal Rubber Particle Size Distribution. U.S. Patent 5,434,218, Jul 18, 1995 BASF. 

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