Characterization of the temperature and humidity-dependent phase diagram of amorphous nanoscale organic aerosols

Mullite (3Al2O3•2SiO2) exists in a solid solution field (∼57-63 mol% Al2O3) as the only stable compound in the Al2O3•SiO2 phase diagram at ambient pressures. Equilibrium 3:2 mullite has an orthorhombic structure with b>a (o-mullite). However, when initially crystallized from molecularly mixed, 3:2 precursors at temperatures < 1200°C, the first phase that forms has lattice parameters with a ≈b. This structure is often termed pseudotetragonal mullite (pt-mullite), since even when the ‘a’ and ‘b’ lattice parameters are identical, they are symmetrically independent. Pseudotetragonal mullite has been shown to contain approx. 70 mol% Al2O3. with increasing time and temperature, the structure gradually assimilates the residual SiO2, and the lattice parameters change, such that by 1400°C, the material has attained its equilibrium structure and composition.TEM was used to determine the spatial relationship between the crystalline phase and the residual, amorphous, SiO2-rich phase in pt-mullite. The starting materials were quenched, 3:2 mullite beads and fibers (made by containerless processing).

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Phase diagram, crystal growth and characterization of Mn-substituted ZnGeAs2 system

Journal of Physics and Chemistry of Solids ◽

10.1016/j.jpcs.2007.07.004 ◽

2008 ◽

Vol 69 (2-3) ◽

pp. 408-410 ◽

Cited By ~ 3

Author(s):

Hiroaki Matsushita ◽

Masaki Watanabe ◽

Akinori Katsui

Keyword(s):

Phase Diagram ◽

Crystal Growth

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A complete characterization of the structure of the vesicular phase in AOT — Brine system in the diluted region of the phase diagram

Colloids and Surfaces A Physicochemical and Engineering Aspects ◽

10.1016/j.colsurfa.2018.09.052 ◽

2018 ◽

Vol 559 ◽

pp. 218-225 ◽

Cited By ~ 3

Author(s):

Julie Wolanin ◽

Loïc Barre ◽

Christine Dalmazzone ◽

Daniela Bauer

Keyword(s):

Phase Diagram ◽

Complete Characterization

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Phase state diagram of a poly(amic acid)–solvent–nonsolvent system

Russian Chemical Bulletin ◽

10.1007/s11172-018-2296-z ◽

2018 ◽

Vol 67 (10) ◽

pp. 1831-1837 ◽

Cited By ~ 1

Author(s):

A. A. Shcherbina ◽

V. K. Gerasimov ◽

T. P. Semenov ◽

A. E. Chalykh

Keyword(s):

Phase State ◽

State Diagram ◽

Amic Acid

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Weathering features of a remineralizer in soil under different land uses

Pesquisa Agropecuária Brasileira ◽

10.1590/s1678-3921.pab2021.v56.01442 ◽

2021 ◽

Vol 56 ◽

Author(s):

Rafael Cipriano da Silva ◽

Edilene Pereira Ferreira ◽

Antonio Carlos de Azevedo

Keyword(s):

Amorphous Phase ◽

Ammonium Oxalate ◽

Total Content ◽

Sodium Dithionite ◽

Land Uses ◽

Elephant Grass ◽

X Ray ◽

Time Periods ◽

Gains And Losses

Abstract The objective of this work was to analyze the mineralogical, morphological, and compositional modifications resulting from the weathering of diabase grains buried into soil under different land uses for up to 378 days. Samples of comminuted diabase were put into polyester bags and buried into soil under corn crop, elephant grass, and woods, being unburied and evaluated after four time periods. The samples of the remineralizer (RM) were analyzed by X-ray diffractometry, total chemical analysis, scanning electron microscopy, and Al (Ald and Alo) and Fe (Fed and Feo) contents extracted by sodium dithionite-citrate-bicarbonate (DCB) and ammonium oxalate (AAO) solutions. Plagioclases and pyroxenes were the most weathered minerals in all three land uses and showed the same pattern of elemental gains and losses. The characterization of Fe and Al solubility in DCB and AAO showed that the greatest change in these elements was from the lithogenic and crystalline to the pedogenic and amorphous phase, when compared with their total content. Plagioclases and pyroxenes were the most weathered minerals, and Fe and Al show a great transfer from the crystalline to the amorphous phase, with values up to 26 and 175, respectively, for the ratios between bags with RM/Feo and RM-control and bags with RM/Alo and RM-control.

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Thermodynamic characterization of Mexico City aerosol during MILAGRO 2006

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-7-9203-2007 ◽

2007 ◽

Vol 7 (3) ◽

pp. 9203-9233 ◽

Cited By ~ 17

Author(s):

C. Fountoukis ◽

A. Nenes ◽

A. Sullivan ◽

R. Weber ◽

T. VanReken ◽

...

Keyword(s):

Gas Phase ◽

Mexico City ◽

Thermodynamic Equilibrium ◽

Phase State ◽

Molar Ratio ◽

Inorganic Species ◽

Equilibrium Calculations ◽

Thermodynamic Equilibrium Model ◽

Thermodynamic Equilibrium Calculations

Abstract. Fast measurements of aerosol and gas-phase constituents coupled with the ISORROPIA-II thermodynamic equilibrium model are used to study the partitioning of semivolatile inorganic species and phase state of Mexico City aerosol sampled at the T1 site during the MILAGRO 2006 campaign. Overall, predicted semivolatile partitioning agrees well with measurements. PM2.5 is insensitive to changes in ammonia but is to acidic semivolatile species. Semi-volatile partitioning equilibrates on a timescale between 6 and 20 min. When the aerosol sulfate-to-nitrate molar ratio is less than 1, predictions improve substantially if the aerosol is assumed to follow the deliquescent phase diagram. Treating crustal species as "equivalent sodium" (rather than explicitly) in the thermodynamic equilibrium calculations introduces important biases in predicted aerosol water uptake, nitrate and ammonium; neglecting crustals further increases errors dramatically. This suggests that explicitly considering crustals in the thermodynamic calculations are required to accurately predict the partitioning and phase state of aerosols.

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