A Matrix Representation of Polymer Chain Size Distributions, 1. Linear Polymerization Mechanisms at Steady-State Conditions

Author(s):  
José Carlos Pinto
2007 ◽  
Vol 16 (2) ◽  
pp. 178-193 ◽  
Author(s):  
Heloísa L. Sanches ◽  
Príamo A. Melo ◽  
José Carlos Pinto

1985 ◽  
Vol 45 (4) ◽  
pp. 523-540 ◽  
Author(s):  
Kenneth B. Hannsgen ◽  
John J. Tyson ◽  
Layne T. Watson

Icarus ◽  
2003 ◽  
Vol 164 (2) ◽  
pp. 334-345 ◽  
Author(s):  
David P. O'Brien ◽  
Richard Greenberg

2008 ◽  
Vol 8 (1) ◽  
pp. 3665-3692 ◽  
Author(s):  
J. C. Wilson ◽  
S.-H. Lee ◽  
J. M. Reeves ◽  
C. A. Brock ◽  
H. H. Jonsson ◽  
...  

Abstract. Measurements of aerosol, N2O and OCS made in the Northern Hemisphere below 21 km altitude following the eruption of Pinatubo are presented and analyzed. After September 1999, the oxidation of OCS and the sedimentation of particles in the extra-tropical overworld maintain the aerosol in a steady state. This analysis empirically links precursor gas to aerosol abundance throughout this region. These processes are tracked with age-of-air which offers advantages over tracking as a function of latitude and altitude. In the extra-tropical, lowermost stratosphere, normalized volume distributions appear constant in time after the fall of 1999. Exchange with the troposphere is important in understanding aerosol evolution there. Size distributions of volcanically perturbed aerosol are included to distinguish between volcanic and non-volcanic conditions. This analysis suggests that model failures to correctly predict OCS and aerosol properties below 20 km in the Northern Hemisphere extra tropics result from inadequate descriptions of atmospheric circulation.


2009 ◽  
Vol 19 (11) ◽  
pp. 2039-2064 ◽  
Author(s):  
IONEL SORIN CIUPERCA ◽  
LIVIU IULIAN PALADE

The configurational distribution function, solution of an evolution (diffusion) equation of the Fokker–Planck–Smoluchowski type, is (at least part of) the corner stone of polymer dynamics: it is the key to calculating the stress tensor components. This can be reckoned from Ref. 1, where a wealth of calculation details is presented regarding various polymer chain models and their ability to accurately predict viscoelastic flows. One of the simplest polymer chain idealization is the Bird and Warner's model of finitely extensible nonlinear elastic (FENE) chains. In this work we offer a proof that the steady state configurational distribution equation has unique solutions irrespective of the (outer) flow velocity gradients (i.e. for both slow and fast flows).


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