The pressure dependence of the dehydration of gypsum to bassanite

1987 ◽  
Vol 51 (361) ◽  
pp. 453-457 ◽  
Author(s):  
J. D. C. McConnell ◽  
D. M. Astill ◽  
P. L. Hall
Keyword(s):  
Elevated Temperature ◽  
Experimental Determination ◽  
Volume Change ◽  
Pressure Dependence ◽  
Thermodynamic Data ◽  
Dehydration Reaction ◽  
Temperature And Pressure ◽  
The Stability ◽  
Very High

AbstractA new experimental determination of the stability relationships for the dehydration of gypsum to the hemihydrate mineral bassanite at elevated temperature and pressure is described. The experimental method used depends on the observation of very small changes in pressure on the onset of reaction due to the potential volume change in the reaction. The technique yields P-T data of very high precision for this dehydration reaction, and the method is likely to be of use for other reactions. The experimental P-T results have been compared with those calculated from existing thermodynamic data for this reaction.

Determination of the Stability of the AIO+ Complex in Alkali Halide Melts*

1984 ◽  
Vol 39 (5) ◽  
pp. 499-502 ◽  
Author(s):  
C. M. Wai ◽  
M. Blander
Keyword(s):  
Free Energy ◽  
Bond Strength ◽  
Mole Fraction ◽  
Thermodynamic Data ◽  
Alkali Halide ◽  
Formation Constant ◽  
Activation Technique ◽  
Eutectic Mixtures ◽  
The Stability

The solubilities of Al182O3 in LiCl-KCl eutectic mixtures containing dissolved AlCl3 were measured using a sensitive proton activation technique. The results are consistent with the presence of an A10+ species at 4.7 x 10-5 mole fraction with AlCl3 at 10-2 mole fraction. When combined with other thermodynamic data, these solubilities are used to deduce a formation constant for the A10+ species from Al3+ and O2- ions of 1.94 x 1022 (in mole fraction units) and a specific bond free energy ("bond strength") of 300 kJ mol-1

scholarly journals Temperature Variation at Solid-Fluid Interface of Thin Film Lubricated Contact Problems

Processes ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 922
Author(s):  
Szabolcs Szávai ◽  
Sándor Kovács
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Pressure Dependence ◽  
Hydrodynamic Pressure ◽  
Contact Problems ◽  
Element Formulation ◽  
Temperature And Pressure ◽  
Non Linear System ◽  
Element Method

Many calculating methods have been already developed for solving contact problems of parts such as gears, cams, and followers under fluid film lubrication conditions considering the temperature and pressure dependence. Similarly, the determination of the elasto-hydrodynamic pressure distribution the processes taking place in the lubricant and the contacting bodies, as well as in their environment, have to be dealt with simultaneously for the determination of the temperature field. A system of equation for the modelling of thermo-elastohydrodynamic lubrication between two contacting bodies containing hydrodynamic, thermodynamic, and strength problems is a highly non-linear system which becomes even more so if the temperature and pressure dependence of the material properties are considered. To solve this system, scientists started to use the finite element formulation in the 1960s and it was found to be a promising and reliable method. Earlier, the lubrication analysts used only the h-version finite element method (h-FEM) till 1991, when the first usage of the p-version finite element method (p-FEM) was published in the literature. In order to reduce the problem, in case of point or line contact, the contact bodies can be handled as semi-infinite ones. Following this simplification that had been successfully applied for the gap size determination, a substructure model was defined using analytical solution of the moving heat source. Instead of an iterative way between the solid and fluid problem, in this paper we present an efficient solution when thermal model for lubricant and surfaces were coupled and solved by a direct numerical method in one step.

Experimental determination of the3He-B g-shift pressure dependence

1994 ◽  
Vol 194-196 ◽  
pp. 751-752 ◽  
Author(s):  
T.M. Haard ◽  
J.B. Kycia ◽  
M.R. Rand ◽  
H.H. Hensley ◽  
G.F. Moores ◽  
...  
Keyword(s):  
Experimental Determination ◽  
Pressure Dependence
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