On the optimal conditions for the homogeneous nucleation of cubic ice from concentrated solutions of lithium chloride-deuterium oxide

1983 ◽  
Vol 87 (21) ◽  
pp. 4170-4173 ◽  
Author(s):  
A. Elarby-Aquizerat ◽  
J. F. Jal ◽  
C. Ferradou ◽  
J. Dupuy ◽  
P. Chieux ◽  
...  
Keyword(s):  
Lithium Chloride ◽  
Homogeneous Nucleation ◽  
Deuterium Oxide ◽  
Optimal Conditions ◽  
Concentrated Solutions

Amorphous silica coating on α-alumina particles

1995 ◽  
Vol 53 ◽  
pp. 210-211
Author(s):  
J. W. Mellowes ◽  
C. M. Chun ◽  
I. A. Aksay
Keyword(s):  
Amorphous Silica ◽  
Heterogeneous Nucleation ◽  
Homogeneous Nucleation ◽  
Silica Coating ◽  
Full Density ◽  
Optimal Conditions ◽  
Fine Grained ◽  
Alumina Particles ◽  
Complete Mullitization ◽  
Powder Compacts

Mullite (3Al2O32SiO2) can be fabricated by transient viscous sintering using composite particles which consist of inner cores of a-alumina and outer coatings of amorphous silica. Powder compacts prepared with these particles are sintered to almost full density at relatively low temperatures (~1300°C) and converted to dense, fine-grained mullite at higher temperatures (>1500°C) by reaction between the alumina core and the silica coating. In order to achieve complete mullitization, optimal conditions for coating alumina particles with amorphous silica must be achieved. Formation of amorphous silica can occur in solution (homogeneous nucleation) or on the surface of alumina (heterogeneous nucleation) depending on the degree of supersaturation of the solvent in which the particles are immersed. Successful coating of silica on alumina occurs when heterogeneous nucleation is promoted and homogeneous nucleation is suppressed. Therefore, one key to successful coating is an understanding of the factors such as pH and concentration that control silica nucleation in aqueous solutions. In the current work, we use TEM to determine the optimal conditions of this processing.

scholarly journals Study of Cellulose Interaction with Concentrated Solutions of Sulfuric Acid

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Michael Ioelovich
Keyword(s):  
Sulfuric Acid ◽  
High Power ◽  
Room Temperature ◽  
Regenerated Cellulose ◽  
Structure And Properties ◽  
Optimal Conditions ◽  
Initial Sample ◽  
Concentrated Solutions ◽  
Crystallinity Degree ◽  
20 Nm

The effect of the concentration of sulfuric acid (SA) and temperature on structure and properties of cellulose (MCC) had been studied. Investigations showed that solubility of the initial sample at the room temperature increased gradually in the range of the acid concentration from 50 to 60 wt.% SA. When SA concentration reached 65 wt.%, then MCC sample dissolved completely. Cellulose regenerated from 65 wt.% SA had an amorphized structure and was characterized by high enzymatic digestibility. At increased temperature, 45°C, solubility of MCC in SA was raised, while yield and DP decreased. After treatment of MCC with hot 50–60 wt.% SA, the crystallinity degree of the obtained cellulose samples changed slightly, and these samples retained mainly the CI crystalline polymorph. However, when SA concentration reached 65 wt.%, then regenerated cellulose had CII crystalline polymorph, reduced crystallinity degree, and low DP. Using optimal conditions of the acidic treatment (57–60 wt.% SA, T = 45°C; t=1 h) in combination with the high-power disintegration permitted obtaining the CI nanocrystalline cellulose particles (NCP) having sizes 150–200 × 10–20 nm with the heightened yield (65–70%). These NCP can be used, for example, as reinforcing nanofillers for various composites.

Spectroscopic study of chloroiron(II) complexes in lithium chloride-deuterium chloride-deuterium oxide solutions

1987 ◽  
Vol 26 (2) ◽  
pp. 308-313 ◽  
Author(s):  
Lynn Vogel Koplitz ◽  
Donald S. McClure ◽  
David A. Crerar
Keyword(s):  
Spectroscopic Study ◽  
Lithium Chloride ◽  
Deuterium Oxide ◽  
Deuterium Chloride
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