scholarly journals Thermodynamics of formation of solid solutions between BaZrO3 and BaPrO3

2020 ◽  
Vol 7 (2) ◽  
pp. 42-50
Author(s):  
Dmitry S. Tsvetkov ◽  
Vladimir V. Sereda ◽  
Dmitry A. Malyshkin ◽  
Anton L. Sednev-Lugovets ◽  
Andrey Yu. Zuev ◽  
...  
Keyword(s):  
Gibbs Energy ◽  
Enthalpy Of Mixing ◽  
Perovskite Oxides ◽  
Standard Enthalpy Of Formation ◽  
Standard Entropy ◽  
Ideal Solution ◽  
Precise Method ◽  
Binary Oxides ◽  
Relative Change ◽  
Thermodynamics Of Formation

A linear relationship between the standard enthalpy of formation from binary oxides, ΔfHox, and the Goldschmidt tolerance factor, t, for some AIIBIVO3 (A = Ca, Sr, Ba; B = Ti, Zr, Hf, Ce, Pr, Tb, U, Pu, Am) perovskite oxides was used for estimation of ΔfHox of Pr-substituted barium zirconates BaZr1–xPrxO3. A dependence of the relative change of the standard entropies, S298, on the relative change of the molar volumes in the reactions of formation of AIIBIVO3 (A = Ca, Sr, Ba; B = Ti, Zr, Hf, Ce) from binary oxides was also found to be linear. Using this dependence, a relatively precise method of estimating S298 was proposed, and S298 of BaPrO3 was calculated as (162.8 ± 2.8) J·mol-1·K-1. Knowing S298 of BaPrO3 and using the literature data for S298 of BaZrO3, the values of S298 of BaZr1–xPrxO3 were predicted on the assumption that BaZr1–xPrxO3 is a regular or ideal solution of BaPrO3 in BaZrO3 as evidenced by the very small enthalpy of mixing calculated based on the estimated ΔfHox. The values of standard entropy changes, ΔfSox, and Gibbs energy changes, ΔfGox, for the reactions of formation of BaZr1–xPrxO3 from BaO, ZrO2 and PrO2 were also estimated. Substituting Pr for Zr in BaZr1–xPrxO3 results in ΔfHox and ΔfGox becoming more positive, indicating the decrease of the relative stability with respect to the corresponding binary oxides. Expanded uncertainties of the estimated values of ΔfHox and ΔfGox are equal to 14 kJ∙mol-1, and those of S298 and ΔfSox – less than 2.8 J∙mol-1·K-1 and 3.5 J∙mol-1·K-1, respectively, for BaZr1–xPrxO3 (x = 0.0–1.0).

Standard Gibbs energy of formation of Pb2Ru2O6.5

2007 ◽  
Vol 22 (5) ◽  
pp. 1174-1181 ◽  
Author(s):  
K.T. Jacob ◽  
V.S. Saji ◽  
Y. Waseda
Keyword(s):  
Gibbs Energy ◽  
Standard Gibbs Energy ◽  
Auxiliary Information ◽  
Standard Enthalpy Of Formation ◽  
Standard Entropy ◽  
Gibbs Energy Of Formation ◽  
Measuring Electrode ◽  
Bifunctional Electrocatalyst ◽  
Image Position ◽  
Energy Of Formation

Lead ruthenate is used as a bifunctional electrocatalyst for both oxygen evolution and reduction and as a conducting component in thick-film resistors. It also has potential applications in supercapacitors and solid oxide fuel cells. However, thermodynamic properties of the compound have not been reported in the literature. The standard Gibbs energy of formation has now been determined in the temperature range from 873 to 1123 K using a solid-state cell incorporating yttria-stabilized zirconia (YSZ) as the electrolyte, a mixture of PbO + Pb2Ru2O6.5 + Ru as the measuring electrode, and Ru + RuO2 as the reference. The design of the measuring electrode is based on a study of phase relations in the ternary system Pb–Ru–O at 1123 K. For the reaction,the standard enthalpy of formation and standard entropy at 298.15 K are estimated from the high-temperature measurements. An oxygen potential diagram for the system Pb–Ru–O is composed based on data obtained in this study and auxiliary information from the literature

Activities of Components in the Ca2MgSi2O7-CaSiO3Molten System

1996 ◽  
Vol 61 (6) ◽  
pp. 837-843
Author(s):  
Ladislav Kosa ◽  
Ivan Nerád ◽  
Katarína Adamkovičová ◽  
Jozef Strečko ◽  
Ivo Proks
Keyword(s):  
Gibbs Energy ◽  
Molar Mass ◽  
Excess Entropy ◽  
Enthalpy Of Mixing ◽  
Real Particle ◽  
Entropy Of Mixing ◽  
Energy Of Mixing ◽  
Gibbs Energy Of Mixing

Activities of the components, the Gibbs energy of mixing, and the excess entropy of mixing have been calculated for the Ca2MgSi2O7-CaSiO3 system. The mole fractions of the components were calculated assuming that in the point of the formal component Ca2MgSi2O7, the molar mass of the quasi-real particle in the melt corresponds to its formula molar mass, whereas in the point of the formal component CaSiO3 the molar mass of the quasi-real particle in the melt is 8.5 times higher than as corresponds to its formula. The fact that the enthalpy of mixing is zero whereas the excess entropy of mixing is non-zero suggests that Ca2MgSi2O7-CaSiO3 melts behave as athermal solutions.

A Camera-Based System for Determining Hand Range of Movement Measurements in Rheumatoid Arthritis

2015 ◽  
pp. 39-59
Author(s):  
Aaron Bond ◽  
Kevin Curran
Keyword(s):  
Rheumatoid Arthritis ◽  
Cost Effective ◽  
Ideal Solution ◽  
Kinect Sensor ◽  
Range Of Movement ◽  
Precise Method ◽  
Kinect Camera ◽  
Xbox Kinect ◽  
Method Of Assessment ◽  
Hand Recognition

Rheumatoid arthritis affects around 1% of the world's population. Detection of the disease relies heavily on observation by physicians. The effectiveness of these kinds of tests is dependent on the ability and experience and can vary depending on the observer. This chapter aims to investigate the use of Xbox Kinect camera for monitoring in rheumatoid arthritis patients as a cost-effective and precise method of assessment. A system has been developed that implements the Kinect sensor for usage in a hand recognition and digit measurement capacity. This system performs the tasks usually completed by a physician such as digit dimension monitoring and exercise observations. With the system being designed to be portable and easy-to-use, it is an ideal solution for both the physician monitoring patients in a clinic as well as posing a possible solution for patients wishing to monitor their own condition in their homes.

Electrical Properties of TaOx Thin Films for ReRAM Prepared by Reactive RF Magnetron Sputtering Method

2010 ◽  
Vol 1250 ◽  
Author(s):  
Natsuki Fukuda ◽  
Hidenao Kurihara ◽  
Kazumasa Horita ◽  
Yoshiaki Yoshida ◽  
Yutaka Kokaze ◽  
...  
Keyword(s):  
Magnetron Sputtering ◽  
Flash Memory ◽  
Nonvolatile Memory ◽  
Scaling Limit ◽  
Rf Magnetron Sputtering ◽  
Perovskite Oxides ◽  
Next Generation ◽  
Forming Process ◽  
Binary Oxides ◽  
Reactive Rf Magnetron Sputtering

AbstractRecently the Flash Memory is scaling limit, Thus the Memory of various types is now under study for the next generation large capacity nonvolatile memory. Resistance random access memory (ReRAM) is attracts much attention due to its advantage for integration in the next generation nonvolatile memory, because it is depend on scaling by lithography compared with the Flash Memory of capacity type. The material for ReRAM is classified roughly into binary oxides and perovskite oxides. Several binary oxides such as a TaOx have the advantage for low-temperature process and low-cost materials compared with perovskite oxides such as a (Pr,Ca)MnO3 (PCMO). In this study, TaOx film with the thickness of 10nm were prepared by reactive RF magnetron sputtering on 8inch-Pt/Si substrate using a Ta metal target in oxygen ambient. The sputtering system was the multi chamber type mass production tool. The TaOx thin film was amorphous phase as a result of measurement by X-ray diffraction meter. Ta top electrodes with 50 um diameters were deposited on the surface of TaOx layer by the DC sputtering method using a shadow mask. The “Forming” voltage of TaOx-ReRAM was 5.0V. After “Forming” process, the “Set” and “Reset” voltage were 3.0V and –3.0V respectively. It has good switching properties with large on/off resistance ratio above 1,000.

Potassium-bearing clinopyroxene: a review of experimental, crystal chemical and thermodynamic data with petrological applications

2011 ◽  
Vol 75 (4) ◽  
pp. 2467-2484 ◽  
Author(s):  
O. G. Safonov ◽  
L. Bindi ◽  
V. L. Vinograd
Keyword(s):  
Thermodynamic Data ◽  
Field Model ◽  
Atomistic Simulations ◽  
Standard Enthalpy Of Formation ◽  
Standard Entropy ◽  
Mixing Properties ◽  
Crustal Rocks ◽  
Mineral Equilibria ◽  
Mineral Assemblages ◽  
Experimental Crystal

AbstractAvailable experimental data on chemical composition and crystal structure of K-bearing clinopyroxenes are compiled together with the results of atomistic simulations and thermodynamic calculations of mineral equilibria. It is shown that the limited solubility of K2O in clinopyroxene from crustal rocks cannot be ascribed to the strong non-ideality of mixing between diopside (CaMgSi2O6) and K-jadeite (KAlSi2O6) components. The more likely reason is the instability of the potassic endmember with respect to other K-bearing phases. As the volume effects of typical K-jadeite-forming reactions are negative, the incorporation of K in the clinopyroxene structure becomes less difficult at higher pressure. Atomistic simulations predict that the thermodynamic mixing properties of diopside-K-jadeite solid-solutions at high temperature approach those of a regular mixture with a relatively small positive excess enthalpy. The standard enthalpy of formation (ΔfH° = —2932.7 kJ/mol), the standard volume (V° = 6.479 J mol–1 bar–1) and the isothermal bulk modulus (K0 = 145 GPa) of K-jadeite were calculated from first principles, and the standard entropy (S° = 141.24 J mol–1 K–1) and thermal-expansion coefficient (α = 3.3 x 1CP–5 K–1) of the K-jadeite endmember were estimated using quasi-harmonic lattice-dynamic calculations based on a force-field model. The estimated thermodynamic data are used to compute compositions of K-bearing clinopyroxenes in diverse mineral assemblages within a wide P-T interval. The review substantiates the conclusion that clinopyroxene can serve as an effective container for K at upper-mantle conditions.

Hybrid Monte Carlo and lattice dynamics simulations: the enthalpy of mixing of binary oxides

1998 ◽  
pp. 627-628 ◽  
Author(s):  
John A. Purton ◽  
Jon D. Blundy ◽  
John A. Purton ◽  
Mark B. Taylor ◽  
Gustavo D. Barrera ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Lattice Dynamics ◽  
Enthalpy Of Mixing ◽  
Hybrid Monte Carlo ◽  
Binary Oxides ◽  
Dynamics Simulations

APPLICATIONS OF A NEW TOPOLOGICAL INDEX EDm IN SOME ALIPHATIC HYDROCARBONS

2009 ◽  
Vol 08 (01) ◽  
pp. 19-45 ◽  
Author(s):  
CHANGMING NIE ◽  
YAXIN WU ◽  
RONGYAN WU ◽  
SAIHONG JIANG ◽  
CONGYI ZHOU
Keyword(s):  
Structural Information ◽  
Correlation Coefficients ◽  
Distance Matrix ◽  
Molar Refraction ◽  
Molecular Structures ◽  
Topological Descriptors ◽  
Standard Enthalpy Of Formation ◽  
Standard Entropy ◽  
Structure Property ◽  
Index Matrix

A novel index EDm based on ionicity index matrix, improved distance matrix, and branching degree matrix is used to describe the structural information of the molecule and realizes unique characterization of the molecular structures. The quantitative structure–property relationship (QSPR) models, with correlation coefficients (R) in the range of 0.99–1.00 for standard enthalpy of formation ([Formula: see text]), standard entropy ([Formula: see text]), molar volume (V m ), and molar refraction (R m ) of alkanes, alkenes, and alkynes, are subsequently developed using the index EDm. The leave-one-out (LOO) method and random sampling prediction (RSP) method demonstrate the models to be statistically significant and reliable. Compared with other published topological descriptors, the index EDm has many advantages such as zero degeneracy, better simulation, and so on. Furthermore, the models of solubility and octanol–water partition coefficient are built with satisfied results, which further manifests the superiority and wide application of this index.

Sign in / Sign up

Export Citation Format

Share Document