In situ charge neutralization on governing particle coagulation nucleation and size distribution in macroemulsion polymerization

RSC Advances ◽  
2016 ◽  
Vol 6 (91) ◽  
pp. 88701-88706 ◽  
Author(s):  
B. J. Liu ◽  
W. T. Meng ◽  
M. Y. Zhang ◽  
H. X. Zhang

Fabricating monodispersed polymer latex particles with ∼300 nm size at high monomer concentrations by batch macroemulsion polymerization based on in situ charge neutralization mechanism.

2004 ◽  
Vol 205 (2) ◽  
pp. 165-172 ◽  
Author(s):  
Joerg Bolze ◽  
Matthias Ballauff ◽  
Thorsten Rische ◽  
Daniel Rudhardt ◽  
Jürgen Meixner

1993 ◽  
Vol 58 (10) ◽  
pp. 2266-2271 ◽  
Author(s):  
Herbert Morawetz

Recent studies of polymers in solution and in bulk by energy transfer between two fluorescent labels are reviewed. Such studies are concerned with the equilibrium and dynamics of polymer chain expansion, molecular cluster formation in solution, the miscibility of polymers in bulk, and the interdiffusion of polymer latex particles.


2016 ◽  
Vol 16 (14) ◽  
pp. 9435-9455 ◽  
Author(s):  
Matthew J. Alvarado ◽  
Chantelle R. Lonsdale ◽  
Helen L. Macintyre ◽  
Huisheng Bian ◽  
Mian Chin ◽  
...  

Abstract. Accurate modeling of the scattering and absorption of ultraviolet and visible radiation by aerosols is essential for accurate simulations of atmospheric chemistry and climate. Closure studies using in situ measurements of aerosol scattering and absorption can be used to evaluate and improve models of aerosol optical properties without interference from model errors in aerosol emissions, transport, chemistry, or deposition rates. Here we evaluate the ability of four externally mixed, fixed size distribution parameterizations used in global models to simulate submicron aerosol scattering and absorption at three wavelengths using in situ data gathered during the 2008 Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) campaign. The four models are the NASA Global Modeling Initiative (GMI) Combo model, GEOS-Chem v9-02, the baseline configuration of a version of GEOS-Chem with online radiative transfer calculations (called GC-RT), and the Optical Properties of Aerosol and Clouds (OPAC v3.1) package. We also use the ARCTAS data to perform the first evaluation of the ability of the Aerosol Simulation Program (ASP v2.1) to simulate submicron aerosol scattering and absorption when in situ data on the aerosol size distribution are used, and examine the impact of different mixing rules for black carbon (BC) on the results. We find that the GMI model tends to overestimate submicron scattering and absorption at shorter wavelengths by 10–23 %, and that GMI has smaller absolute mean biases for submicron absorption than OPAC v3.1, GEOS-Chem v9-02, or GC-RT. However, the changes to the density and refractive index of BC in GC-RT improve the simulation of submicron aerosol absorption at all wavelengths relative to GEOS-Chem v9-02. Adding a variable size distribution, as in ASP v2.1, improves model performance for scattering but not for absorption, likely due to the assumption in ASP v2.1 that BC is present at a constant mass fraction throughout the aerosol size distribution. Using a core-shell mixing rule in ASP overestimates aerosol absorption, especially for the fresh biomass burning aerosol measured in ARCTAS-B, suggesting the need for modeling the time-varying mixing states of aerosols in future versions of ASP.


1987 ◽  
Vol 22 (1) ◽  
pp. 39-48 ◽  
Author(s):  
K. Kendall ◽  
J. C. Padget

2014 ◽  
Vol 67 (4) ◽  
pp. 405-412
Author(s):  
Christiane Ribeiro da Silva ◽  
Vládia C. G. de Souza ◽  
Jair C. Koppe

A methodology to determine the size distribution curve of the ROM was developed in a Brazilian iron ore mine. The size of the larger fragments was determined taking photographs and setting the scale of the images to analyze their dimensions (length of their edges and areas). This was implemented according to a specific protocol of sampling that involves split and homogenization stages in situ of a considerable quantity of ore (about 259 metric tonnes). During the sampling process, larger fragments were separated and smaller size material was screened. The methodology was developed initially in order to preview the performance of a primary gyratory crusher that is fed directly from trucks. Operational conditions of the equipment such as closed and open-side settings could be adjusted previously, obtaining different product size distributions. Variability of size of the fragments affects subsequent stages of crushing and can increase circulating load in the circuit. This leads to a decrease of productivity or recovery of the ore dressing. The results showed insignificant errors of accuracy and reproducibility of the sampling protocol when applied to friable itabirite rocks.


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