New Equations for the Thermodynamic Properties of Saturated Water in Both the Liquid and Vapour Phases

1967 ◽  
Vol 9 (1) ◽  
pp. 24-35 ◽  
Author(s):  
M. R. Gibson ◽  
E. A. Bruges

Equations in the form of Chebyshev polynomials are presented which enable the thermodynamic properties of saturated water in its liquid and vapour phases to be calculated in a systematic manner. In the equations defining the pressure-temperature relationship the authors have made allowance for certain unpublished observations of the National Bureau of Standards and these are considered in the section relating to vapour pressure. It is believed that the assembly of equations specify for the first time the saturated liquid and vapour boundaries whose properties have previously only been available in tabular form.

2009 ◽  
Vol 64 (5-6) ◽  
pp. 399-404 ◽  
Author(s):  
Zi-Jiang Liu ◽  
Xiao-Ming Tan ◽  
Yuan Guo ◽  
Xiao-Ping Zheng ◽  
Wen-Zhao Wu

The thermodynamic properties of tetragonal CaSiO3 perovskite are predicted at high pressures and temperatures using the Debye model for the first time. This model combines the ab initio calculations within local density approximation using pseudopotentials and a plane wave basis in the framework of density functional theory, and it takes into account the phononic effects within the quasi-harmonic approximation. It is found that the calculated equation of state is in excellent agreement with the observed values at ambient condition. Based on the first-principles study and the Debye model, the thermal properties including the Debye temperature, the heat capacity, the thermal expansion and the entropy are obtained in the whole pressure range from 0 to 150 GPa and temperature range from 0 to 2000 K.


Molecules ◽  
2019 ◽  
Vol 24 (24) ◽  
pp. 4470
Author(s):  
Jiangtao Song ◽  
Fei Yuan ◽  
Long Li ◽  
Yafei Guo ◽  
Tianlong Deng

The heat capacities on two minerals of hungchaoite (MgB4O7·9H2O, Hu) and mcallisterite (MgB6O10·7.5H2O, Mc) have been measured with a precision calorimeter at temperatures ranging from 306.15 to 355.15 K, experimentally. It was found that there are no phase transition and thermal anomalies, and the molar heat capacities against temperature for the minerals of hungchaoite and mcallisterite were fitted as C p , m , Hu   =   − 27019.23675 + 229.55286 T   −   0.63912 T   2   +   ( 5.95862   ×   10   − 4 )   T   3 and C p , mMc   =   − 9981.88552   +   84.10964 T   −   0.22685 T   2   +   ( 2.0593   ×   10   − 4 )   T   3 , respectively. The molar heat capacities and thermodynamic functions of (HT-H298.15), (ST-S298.15), and (GT-G298.15) at intervals of 1 K for the two minerals were obtained for the first time. These results are significant in order to understand the thermodynamic properties of those minerals existing in nature salt lakes, as well as applying them to the chemical engineering process design.


2010 ◽  
Vol 24 (03) ◽  
pp. 315-324
Author(s):  
ZI-JIANG LIU ◽  
XIAO-WEI SUN ◽  
CAI-RONG ZHANG ◽  
LI-NA TIAN ◽  
YUAN GUO

The thermodynamic properties of MgSiO 3 post-perovskite are predicted at high pressures and temperatures using the Debye model for the first time. This model combines with ab initio calculations within local density approximation using pseudopotentials and a plane wave basis in the framework of density functional theory, and it takes into account the phononic effects within the quasi-harmonic approximation. It is found that the calculated equation of state of MgSiO 3 post-perovskite is in excellent agreement with the latest observed values. Based on the first-principles study and the Debye model, the thermal properties including the Debye temperature, the heat capacity, the thermal expansion, and the entropy are obtained in the whole pressure range from 0 to 150 GPa and temperature range from 0 to 2000 K.


Author(s):  
Brandon S. Field

This paper describes guided inquiry investigations of thermodynamic properties and cycles that was used in a sophomore thermodynamics class. A partially-complete computer model of a Carnot cycle was provided to students that was written in Engineering Equation Solver (EES). The students were led through a investigation in pairs or groups using the model designed to familiarize the students with the software as well as the cycle. As part of the investigation, the students were required to modify the model to add features. Following the in-class exercise with the Carnot cycle, students were required to model a Stirling cycle and later a Brayton cycle using the same EES software for a take-home project. In previous classes, the same (and similar) take-home projects were assigned, but this was the first time that these computer projects were preceded by a guided inquiry investigation. The advantages of using such a guided inquiry investigation to introduce the software were primarily evident from the questions that were avoided on the take-home projects, but also evident from the student performance on the projects themselves. A discussion of the investigation is included, as well as critique of what will be changed for the next time the class is taught.


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