scholarly journals Impact of atmospheric water vapor on the thermal decomposition of calcium hydroxide: a universal kinetic approach to a physico-geometrical consecutive reaction in solid–gas systems under different partial pressures of product gas

2019 ◽  
Vol 21 (22) ◽  
pp. 11615-11632 ◽  
Author(s):  
Nobuyoshi Koga ◽  
Loic Favergeon ◽  
Satoki Kodani
Keyword(s):  
Thermal Decomposition ◽  
Water Vapor ◽  
Vapor Pressure ◽  
Water Vapor Pressure ◽  
Atmospheric Water Vapor ◽  
Atmospheric Water ◽  
Consecutive Reaction ◽  
Product Gas ◽  
Partial Pressures ◽  
Kinetics Of

Impact of atmospheric water vapor pressure on the kinetics of the thermal decomposition of Ca(OH)2 can be described universally.

scholarly journals Revealing the effect of water vapor pressure on the kinetics of thermal decomposition of magnesium hydroxide

2020 ◽  
Vol 22 (24) ◽  
pp. 13637-13649 ◽  
Author(s):  
Satoki Kodani ◽  
Shun Iwasaki ◽  
Loïc Favergeon ◽  
Nobuyoshi Koga
Keyword(s):  
Thermal Decomposition ◽  
Water Vapor ◽  
Vapor Pressure ◽  
Magnesium Hydroxide ◽  
Water Vapor Pressure ◽  
Kinetics Of Thermal Decomposition ◽  
Effect Of Water ◽  
Kinetics Of ◽  
Kinetic Features

Kinetic features of the thermal decomposition of Mg(OH)2 are revealed under different heating and water vapor pressure conditions.

Transient Behavior of Near Frictionless Carbon Films in Reciprocating Microtribometery in Low Humidity Inert Environments

2005 ◽  
Author(s):  
P. L. Dickrell ◽  
A. Erdemir ◽  
W. G. Sawyer
Keyword(s):  
Water Vapor ◽  
Friction Coefficient ◽  
Vapor Pressure ◽  
Environmental Exposure ◽  
Water Vapor Pressure ◽  
Transient Behavior ◽  
Carbon Films ◽  
Partial Pressures ◽  
Low Humidity

Microtribological measurements of near frictionless carbon (NFC) films in controlled gaseous environments show that water vapor plays a role in the friction coefficient. These experiments also show that the NFC films initially have high friction in argon, which then decreases. This high friction does not reform over extended periods of exposure to Ar and low partial pressures of H2O and O2. Tests varying water vapor pressure show that under certain humidity conditions the friction coefficient can increases to values seen after extended periods of environmental exposure.

Quantitation of crystallinity in substantially amorphous pharmaceuticals and study of crystallization kinetics by X-ray powder diffractometry

2000 ◽  
Vol 15 (1) ◽  
pp. 2-6 ◽  
Author(s):  
Rahul Surana ◽  
Raj Suryanarayanan
Keyword(s):  
Water Vapor ◽  
Vapor Pressure ◽  
Crystallization Kinetics ◽  
Water Vapor Pressure ◽  
Three Dimensional ◽  
Weight Percent ◽  
X Ray ◽  
Amorphous Pharmaceuticals ◽  
Integrated Intensities ◽  
Kinetics Of

The first object was to develop an X-ray diffractometric method for the detection and quantification of crystalline sucrose when it occurs as a mixture with amorphous sucrose. Standards consisting of amorphous sucrose physically mixed with 1 to 5 weight percent crystalline sucrose were prepared. The sum of the background subtracted integrated intensities of the 12.7°2θ (6.94 Å) and 13.1°2θ (6.73 Å) sucrose diffraction peaks were linearly related to the weight percent crystalline sucrose. The limits of detection and quantitation of crystalline sucrose were 0.9% and 1.8% w/w, respectively. The second object was to study the kinetics of crystallization of sucrose as a function of temperature (at 102, 105 and 110 °C under a water vapor pressure of 0 Torr) and water vapor pressure (17.4, 19.8 and 21.4 Torr at 27 °C). In all cases, the crystallization kinetics was best described by the Avrami-Erofe’ev model (three-dimensional nucleation).

THE EFFECT OF WATER VAPOR UPON THE DEHYDRATION OF CaSO4•2H2O

1964 ◽  
Vol 42 (4) ◽  
pp. 792-801 ◽  
Author(s):  
H. G. McAdie
Keyword(s):  
Water Vapor ◽  
Vapor Pressure ◽  
Water Vapor Pressure ◽  
Vapor Pressures ◽  
Heat Of Solution ◽  
Temperature Dependent ◽  
Exponential Factor ◽  
Fixed Composition ◽  
Kinetics Of ◽  
Partial Water

Kinetics of the two-stage dehydration of CaSO4•2H2O have been examined under controlled water vapor pressures up to one atmosphere. For both stages water vapor initially accelerated the rate of dehydration and subsequently retarded it. Separate, temperature-dependent water vapor pressures were noted above which each stage could be suppressed.The hemihydrate was clearly defined either as a change in the rate of weight loss during dehydration or, at higher water vapor pressures, as a fixed composition. The heat of solution of the hemihydrate increased linearly with the partial water vapor pressure present during its formation, but was independent of the formation temperature over the range studied. Activation energy and pre-exponential factor for the dihydrate → hemihydrate process also increased linearly with water vapor pressure. Hemihydrates produced at the extremes of water vapor pressure corresponded to the α- and β-modifications, as defined thermodynamically, and the production of a hemihydrate series with properties varying linearly from one extreme to the other is discussed.

Sign in / Sign up

Export Citation Format

Share Document