Thermochemical stability of BaFe12O19 and BaFe2O4 and phase relations in the Ba-Fe-O ternary system

1994 ◽  
Vol 9 (6) ◽  
pp. 1499-1512 ◽  
Author(s):  
Jinshan Li ◽  
Turgut M. Gür ◽  
Robert Sinclair ◽  
Stephen S. Rosenblum ◽  
Hidetaka Hayashi
Keyword(s):  
Ternary Phase ◽  
Ternary Phase Diagram ◽  
Coulometric Titration ◽  
Magnetic Thin Films ◽  
Process Conditions ◽  
Temperature Range ◽  
The Stability ◽  
Stability Limits ◽  
Thermochemical Stability ◽  
Titration Technique

The stability of BaFe12O19 and BaFe2O4 was studied by the oxygen coulometric titration technique between 700 °C and 1000 °C using a solid-state electrochemical cell. This temperature range is technologically important for the deposition of BaFe2O19 magnetic thin films. The thermodynamic information obtained from the titration measurements was corroborated with structural identification of phases prepared under electrochemically controlled conditions. Accordingly, a section of the Ba–Fe–O ternary phase diagram around the BaFe12O19 composition was constructed in this temperature range. The standard Gibbs free energy change for the decomposition of BaFe12O19 into BaFe2O4, Fe3O4, and O2 is given by the expression ΔG°[J/mol] = 7.23 × 105 −480T. In the oxygen pressure-temperature domain, the thermodynamic stability limits of BaFe12O19 and BaFe2O4 are given by the expressions In[Po2(atm)] = 69.37 −1.04 × 105 T−1 and In[Po2(atm)] = 27.68 −7.12 × 104 T−1, respectively. The stability limits determined here help define the process conditions for the successful synthesis of these phases.

Phase chemistry in the Ti-Si-N system: Thermochemical review with phase stability diagrams

1994 ◽  
Vol 9 (9) ◽  
pp. 2362-2369 ◽  
Author(s):  
S. Sambasivan ◽  
W.T. Petuskey
Keyword(s):  
Phase Stability ◽  
Ternary Phase ◽  
Ternary Phase Diagram ◽  
Current Knowledge ◽  
Thermodynamic Activity ◽  
Accurate Information ◽  
Stability Diagrams ◽  
Phase Compatibility ◽  
The Stability ◽  
Phase Chemistry

The phase chemistry and thermodynamics of the Ti-Si-N system are reviewed leading to a revision of the ternary phase diagram at 1273 K to include the extended compositional ranges of δ-TiNx and Ti5Si3(Ny) and the compounds Ti3Si, Ti5Si4, and α-Ti. This same information is presented in the form of phase stability diagrams which plot the stability criteria for each phase as a function of thermodynamic activity of one component and the relative composition of the other two components. Plots in terms of log asi vs Ti/(Ti + N), log aN2 vs Si/(Ti + Si), and log aTi vs N/(Si + N) were constructed. All diagrams are consistent with current knowledge of phase compatibility and, therefore, are topologically correct. Further refinement will be possible as more accurate information on thermodynamics and compositional limits of solid solutions becomes available.

Development of Microemulsion of Phytosteryl Glycoside in DMSO and Tween 20 for Increase Antiamoebic Activity

2016 ◽  
Vol 675-676 ◽  
pp. 27-30
Author(s):  
Chanyapat Sangsuwon ◽  
Weena Jirujchariyakul
Keyword(s):  
Normal Saline ◽  
Ternary Phase ◽  
Ternary Phase Diagram ◽  
Volume Ratio ◽  
Acanthamoeba Keratitis ◽  
Tween 20 ◽  
Methanol Fraction ◽  
Causative Agents ◽  
Antiamoebic Activity ◽  
The Stability

Peperomia pellucida (Piperaceae) of Thai name “Phak kra sang” is medicinal plant. They are eaten in a salad or as cooked vegetable for protected glaucoma, eye inflammation. Recently, The methanol fraction of P. pellucida was tested for antiamoebic effect. Acanthamoeba spp. are protozoa, free-living in the environment and feed on bacteria. Acanthamoeba spp. are the causative agents of Acanthamoeba keratitis. P. pellucida is medicinal plants, and was interesting for studied antiamobic. The separation by column chromatography (CC) used organic solvent of methanol and ethyl acetate (3:7) gave phytosteryl glycoside (PG). Acanthamoeba spp. was cultured in normal saline and PG is organic compound which was poor soluble in normal saline. This study was developed microemulsion (ME) of PG for effective of antiamoebic activity. Pseudo-ternary phase diagram used for identify ME region. The consisting of ME were dimethyl sulfoxide (DMSO), Tween 20, water and PG. Formulations were prepared with prior mixture of DMSO: Tween20 (co-surfactant: surfactant) in four volume ratio 1:1, 2:1, 3:1 and 4:1 which is each of ratio of Smix. PG was concentrated in 200μg/ml in ethanol. Forming of colloids used Smix in ratios 3:1and 4:1.The stability of ME was ratio was PG: Smix water (1: 9: 4.5). The optimized ME formulation and characterized by zeta potential were found to be 121-397 nm, and conductivity-7.0 mV. Under light microscope ME was absorbed into the endocyst of Acanthamoeb spp., and detected the dead cysts by staining of toluidine blue. IC50 showed 0.88 μg/ml for antiamoebic activity.

scholarly journals Oxygen Content and Thermodynamic Stability of YBaCo2O6−δ Double Perovskite

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Anton L. Sednev ◽  
Andrey Yu Zuev ◽  
Dmitry S. Tsvetkov
Keyword(s):  
Oxygen Content ◽  
Thermodynamic Stability ◽  
Crucial Role ◽  
Coulometric Titration ◽  
Stability Limit ◽  
Double Perovskite ◽  
Stability Diagram ◽  
Partial Pressures ◽  
The Stability ◽  
Titration Technique

The thermodynamic stability of the double perovskite YBaCo2O6−δ was studied using the coulometric titration technique and verified by measurements of the overall conductivity depending on oxygen partial pressure at a given temperature. As a result, the stability diagram of YBaCo2O6−δ was plotted. YBaCo2O6−δ was found to be thermodynamically stable in air at 850°C and higher temperatures, whereas its thermodynamic stability at 900°C is limited by the range of oxygen partial pressures −3.56 ≤ log(pO2/atm) ≤ −0.14. Oxygen content in YBaCo2O6−δ slightly decreases at 900°C from 5.035 at log(pO2/atm) = −0.14 to 4.989 in the atmosphere with log(pO2/atm) = −3.565 indicating a crucial role which variation of Co+3/Co+2 ratio plays in its stability. YBaCo2O6−δ decomposes into the mixture of YCoO3 and BaCoO3−z at the high pO2 stability limit, whereas YBaCo4O7, BaCo1−xYxO3−γ, and Y2O3 were identified as the products of its decomposition at the low pO2 one.

Research the Formulation of Triazophos Microemulsion

2011 ◽  
Vol 79 ◽  
pp. 111-116 ◽  
Author(s):  
Da Liao Gong ◽  
Feng Zhao ◽  
Hong Ying Xia ◽  
Ya Qian Wu
Keyword(s):  
Physical Chemistry ◽  
Phase Diagram ◽  
Experimental Method ◽  
Cold Storage ◽  
Ternary Phase ◽  
Heat Storage ◽  
Ternary Phase Diagram ◽  
Distilled Water ◽  
Microemulsion Formulation ◽  
The Stability

Based on physical chemistry pseudo ternary phase diagram and orthogonal experimental method, the method of the component and preparation of pesticide microemulsion was discussed in detail. The heat storage and cold storage tests were used as an indicator to examine the stability of the formulations we obtained. Finally, the best formulation was obtained as follows: triazophos (2.946%), surfactant DK90 (7.232%), ethanol (4.821%), stabilizer A (0.4841%), distilled water (84.52%). Experimental results show that our method is simple, scientific and effective. It is beneficial for us to select the microemulsion formulation.

Application of a Ternary Phase Diagram To Describe the Stability of Residual Marine Fuel

2019 ◽  
Vol 33 (5) ◽  
pp. 4671-4675 ◽  
Author(s):  
Natalia K. Kondrasheva ◽  
Viacheslav A. Rudko ◽  
Dmitrii O. Kondrashev ◽  
Viktoria S. Shakleina ◽  
Ksenia I. Smyshlyaeva ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Ternary Phase ◽  
Ternary Phase Diagram ◽  
Marine Fuel ◽  
The Stability

scholarly journals Utilization of Cumbeba (Tacinga inamoena) Residue: Drying Kinetics and Effect of Process Conditions on Antioxidant Bioactive Compounds

Foods ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 788
Author(s):  
João Paulo de Lima Ferreira ◽  
Alexandre José de Melo Queiroz ◽  
Rossana Maria Feitosa de Figueirêdo ◽  
Wilton Pereira da Silva ◽  
Josivanda Palmeira Gomes ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Bioactive Compounds ◽  
Fixed Bed ◽  
Drying Kinetics ◽  
Raw Material ◽  
Process Conditions ◽  
Temperature Range ◽  
Water Diffusivity ◽  
Pharmaceutical Industries ◽  
Effective Water

The residue generated from the processing of Tacinga inamoena (cumbeba) fruit pulp represents a large amount of material that is discarded without proper application. Despite that, it is a raw material that is source of ascorbic acid, carotenoids and phenolic compounds, which are valued in nutraceutical diets for allegedly combating free radicals generated in metabolism. This research paper presents a study focused on the mathematical modeling of drying kinetics and the effect of the process on the level of bioactive of cumbeba residue. The experiments of cumbeba residue drying (untreated or whole residue (WR), crushed residue (CR) and residue in the form of foam (FR)) were carried out in a fixed-bed dryer at four air temperatures (50, 60, 70 and 80 °C). Effective water diffusivity (Deff) was determined by the inverse method and its dependence on temperature was described by an Arrhenius-type equation. It was observed that, regardless of the type of pretreatment, the increase in air temperature resulted in higher rate of water removal. The Midilli model showed better simulation of cumbeba residue drying kinetics than the other models tested within the experimental temperature range studied. Effective water diffusivity (Deff) ranged from 6.4890 to 11.1900 × 10−6 m2/s, 2.9285 to 12.754 × 10−9 m2/s and 1.5393 × 10−8 to 12.4270 × 10−6 m2/s with activation energy of 22.3078, 46.7115 and 58.0736 kJ/mol within the temperature range of 50–80 °C obtained for the whole cumbeba, crushed cumbeba and cumbeba residue in the form of foam, respectively. In relation to bioactive compounds, it was observed that for a fixed temperature the whole residue had higher retention of bioactive compounds, especially phenolic compounds, whereas the crushed residue and the residue in the form of foam had intermediate and lower levels, respectively. This study provides evidence that cumbeba residue in its whole form can be used for the recovery of natural antioxidant bioactive compounds, mainly phenolic compounds, with the possibility of application in the food and pharmaceutical industries.

Using phase boundary mapping to resolve discrepancies in the Mg2Si–Mg2Sn miscibility gap

2021 ◽  
Author(s):  
Rachel Orenstein ◽  
James P. Male ◽  
Michael Toriyama ◽  
Shashwat Anand ◽  
G. Jeffrey Snyder
Keyword(s):  
Phase Diagram ◽  
Phase Boundary ◽  
Ternary Phase ◽  
Ternary Phase Diagram ◽  
Miscibility Gap ◽  
Boundary Mapping

A new understanding of the MgSi–MgSn miscibility gap is reached through phase boundary mapping the Mg–Si–Sn ternary phase diagram.

Stability as a constraint in sagittal plane human force exertion modeling

1998 ◽  
Vol 1 (1) ◽  
pp. 23-39
Author(s):  
Carter J. Kerk ◽  
Don B. Chaffin ◽  
W. Monroe Keyserling
Keyword(s):  
Muscle Strength ◽  
Ankle Joint ◽  
Coefficient Of Friction ◽  
Sagittal Plane ◽  
Biomechanical Model ◽  
Whole Body ◽  
The Stability ◽  
Joint Center ◽  
Static Conditions ◽  
Stability Limits

The stability constraints of a two-dimensional static human force exertion capability model (2DHFEC) were evaluated with subjects of varying anthropometry and strength capabilities performing manual exertions. The biomechanical model comprehensively estimated human force exertion capability under sagittally symmetric static conditions using constraints from three classes: stability, joint muscle strength, and coefficient of friction. Experimental results showed the concept of stability must be considered with joint muscle strength capability and coefficient of friction in predicting hand force exertion capability. Information was gained concerning foot modeling parameters as they affect whole-body stability. Findings indicated that stability limits should be placed approximately 37 % the ankle joint center to the posterior-most point of the foot and 130 % the distance from the ankle joint center to the maximal medial protuberance (the ball of the foot). 2DHFEC provided improvements over existing models, especially where horizontal push/pull forces create balance concerns.

Calculation of phase diagrams and thermodynamic properties of 14 additive and reciprocal ternary systems containing Li2CO3, Na2CO3, K2CO3, Li2SO4, Na2SO4, K2SO4, LiOH, NaOH, and KOH

1984 ◽  
Vol 62 (3) ◽  
pp. 457-474 ◽  
Author(s):  
A. D. Pelton ◽  
C. W. Bale ◽  
P. L. Lin
Keyword(s):  
Phase Diagram ◽  
Thermodynamic Properties ◽  
Molten Salt ◽  
Phase Diagrams ◽  
Binary Systems ◽  
Ternary Phase ◽  
Ternary Phase Diagram ◽  
Ternary Systems ◽  
Maximum Error ◽  
Critical Assessment

Phase diagrams and thermodynamic properties of five additive molten salt ternary systems and nine reciprocal molten salt ternary systems containing the ions Li+, Na+, [Formula: see text], OH− are calculated from the thermodynamic properties of their binary subsystems which were obtained previously by a critical assessment of the thermodynamic data and the phase diagrams in these binary systems. Thermodynamic properties of ternary liquid phases are estimated from the binary properties by means of the Conformal Ionic Solution Theory. The ternary phase diagrams are then calculated from these thermodynamic properties by means of computer programs designed for the purpose. It is found that a ternary phase diagram can generally be calculated in this way with a maximum error about twice that of the maximum error in the binary phase diagrams upon which the calculations are based. If, in addition, some reliable ternary phase diagram measurements are available, these can be used to obtain small ternary correction terms. In this way, ternary phase diagram measurements can be smoothed and the isotherms drawn in a thermodynamically correct way. The thermodynamic approach permits experimental data to be critically assessed in the light of thermodynamic principles and accepted solution models. A critical assessment of error limits on all the calculated ternary diagrams is made, and suggestions as to which composition regions merit further experimental study are given.

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