scholarly journals STUDY ON THE STABILITY OF TRIVALENT CATIONS GADOLINIUM (Gd) DOPED FERRIC OXIDE (Fe2O3) THROUGH ATOMISTIC MODELING

2020 ◽  
Vol 5 (2) ◽  
pp. 53
Author(s):  
Anggi Suprabawati
Keyword(s):  
Ferric Oxide ◽  
Atomistic Modeling ◽  
Trivalent Cations ◽  
The Stability

scholarly journals Study on the Stability of Trivalent Cations Doped Zirconia through Atomistic Modeling

2019 ◽  
Vol 22 (4) ◽  
pp. 129-135
Author(s):  
Akram La Kilo ◽  
Triwahyuni S. Umamah ◽  
Lukman A. R. Laliyo
Keyword(s):  
Geometry Optimization ◽  
Lattice Energy ◽  
Atomistic Modeling ◽  
Cell Parameters ◽  
Short Range Potential ◽  
Atomistic Modelling ◽  
Trivalent Cations ◽  
The Difference ◽  
The Stability ◽  
Good Agreement

The aim of this research was to study the stability of the structure of the ZrO2 doped with trivalent oxide Zr1-xMxO2-δ (M = La3+, Nd3+, Sm3+, Eu3+, Gd3+, Y3+, Er3+, Yb3+ and Lu3+ through atomistic modelling and bond valence sum method. Short range potential used in this study was Buckinghams’ potential. Result of geometry optimization at constant pressure shown both cell parameters of ZrO2 was in good agreement with experimental results because of the difference was only 0.11%. Increasing the concentration and the size of substituting dopant of ZrO2 makes the lattice energy of the doped structure was more positive so that the stability of the doped ZrO2 structure decreases. The decrease in the stability of ZrO2 doped with Y3+, Er3+, Yb3+ and Lu3+was smaller than ZrO2 doped with La3+, Nd3+, Sm3+, Eu3+ and Gd3+. BVS results shown that the structure of ZrO2 doped with La3+was not appropriate because it has different value of BVS was more than 0.1

The Influence of X Radiation on the Stability of Ferric Oxide Sol

1936 ◽  
Vol 9 (106) ◽  
pp. 631-636 ◽  
Author(s):  
J. A. Crowther ◽  
H. Liebmann ◽  
C. C. Mills
Keyword(s):  
Ferric Oxide ◽  
The Stability

A molecular dynamics investigation on grain disappearance at a triple junction in polycrystalline silicon

2001 ◽  
Vol 677 ◽  
Author(s):  
Alessandra Satta ◽  
Luciano Colombo ◽  
Fabrizio Cleri
Keyword(s):  
Molecular Dynamics ◽  
Triple Junction ◽  
Polycrystalline Silicon ◽  
Critical Radius ◽  
Interatomic Potential ◽  
Atomistic Modeling ◽  
Triple Junctions ◽  
Atomistic Region ◽  
The Stability ◽  
Dynamics Simulations

ABSTRACTTopological changes in microstructure are strictly related to the microscopic evolution of triple junctions (TJ). The three-sided grain disappearance, usually called T2 process, is here investigated via 3D-atomistic modeling. In particular the stability of a three-sided grain insertion in a triple junction in silicon is studied within the framework of Molecular Dynamics simulations. The Stillinger-Weber interatomic potential is adopted and constant-traction border conditions are considered to ensure a proper embedding of the atomistic region in a virtually infinite bulk continuum. Dealing with the T2-event, the critical radius below which the three- sided inner grain become unstable is evaluated to be three to four times the lattice constant of silicon. Moreover, we show that the instability sets in through the amorphization of the central shrinking grain.

scholarly journals Development and validation of analytical methodology with focus on the qualification of powder mixers

2015 ◽  
Vol 51 (2) ◽  
pp. 273-284 ◽  
Author(s):  
Pedro de Freitas Fiorante ◽  
Rodrigo Dias Martins ◽  
Mauri Sergio Alves Palma
Keyword(s):  
Hydrochloric Acid ◽  
Ferric Oxide ◽  
Analytical Procedure ◽  
Maximum Deviation ◽  
Hydrochloric Acid Concentration ◽  
Intermediate Precision ◽  
Analytical Methodology ◽  
Relative Standard ◽  
Performance Qualification ◽  
The Stability

<p>This study aims at developing an analytical procedure capable of quantifying the ferric oxide present in the mixture of ferric oxide/lactose monohydrate (0.4% w/w). The analytical procedure was checked for specificity, linearity, precision (system repeatability, procedure repeatability and intermediate precision), accuracy, stability of solutions and robustness of the procedure. The concentration of Fe (III) was determined by spectrophotometry at 480 nm based on calibration curves. The specificity was verified. The linearity was obtained in the range of 11.2 to 16.8 µg of ferric oxide/mL. The relative standard deviation (RSD) of the system repeatability, procedure repeatability and intermediate precision, were not more than 2%. The RSD of the accuracy values were less than 0.75%. The stability of the samples was checked over a 24 hours assay. In the robustness evaluation, the wavelength and the concentration of hydrochloric acid varied. The maximum absorbance deviation due to wavelength variation was 0.14 percent, and the maximum deviation due to the hydrochloric acid concentration variation was 2.4%, indicating that the concentration of hydrochloric acid is critical to the analysis of ferric oxide. The procedure developed was validated and is suitable to the performance qualification of powder mixers.</p>

scholarly journals Chemical ordering in substituted fluorite oxides: a computational investigation of Ho2Zr2O7 and RE2Th2O7 (RE=Ho, Y, Gd, Nd, La)

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Jonathan M. Solomon ◽  
Jacob Shamblin ◽  
Maik Lang ◽  
Alexandra Navrotsky ◽  
Mark Asta
Keyword(s):  
Dft Calculations ◽  
Density Functional ◽  
Waste Containment ◽  
Chemical Ordering ◽  
Oxygen Coordination ◽  
Vacancy Ordering ◽  
Trivalent Cations ◽  
Yield Values ◽  
Scattering Study ◽  
The Stability

Abstract Fluorite-structured oxides find widespread use for applications spanning nuclear energy and waste containment, energy conversion, and sensing. In such applications the host tetravalent cation is often partially substituted by trivalent cations, with an associated formation of charge-compensating oxygen vacancies. The stability and properties of such materials are known to be influenced strongly by chemical ordering of the cations and vacancies, and the nature of such ordering and associated energetics are thus of considerable interest. Here we employ density-functional theory (DFT) calculations to study the structure and energetics of cation and oxygen-vacancy ordering in Ho2Zr2O7. In a recent neutron total scattering study, solid solutions in this system were reported to feature local chemical ordering based on the fluorite-derivative weberite structure. The calculations show a preferred chemical ordering qualitatively consistent with these findings, and yield values for the ordering energy of 9.5 kJ/mol-cation. Similar DFT calculations are applied to additional RE2Th2O7 fluorite compounds, spanning a range of values for the ratio of the tetravalent and trivalent (RE) cation radii. The results demonstrate that weberite-type order becomes destabilized with increasing values of this size ratio, consistent with an increasing energetic preference for the tetravalent cations to have higher oxygen coordination.

FERRIC SALT AS THE “SOLUTION LINK” IN THE STABILITY OF FERRIC OXIDE HYDROSOL1

1923 ◽  
Vol 45 (11) ◽  
pp. 2522-2532 ◽  
Author(s):  
Arthur W. Thomas ◽  
Alexander Frieden
Keyword(s):  
Ferric Oxide ◽  
Ferric Salt ◽  
The Stability

scholarly journals Bond valence constraints on the composition of 3d-elements bearing tourmalines

2014 ◽  
Vol 70 (a1) ◽  
pp. C1118-C1118
Author(s):  
Oleg Vereshchagin ◽  
Olga Frank-Kamenetskaya ◽  
Ira Rozhdestvenskaya
Keyword(s):  
Aluminum Content ◽  
Divalent Cations ◽  
Bond Valence ◽  
Trivalent Cation ◽  
Charge Balance ◽  
Bivalent Cations ◽  
3D Elements ◽  
Trivalent Cations ◽  
The Stability ◽  
Good Agreement

F.C. Hawthorne (2002) and F. Bosi (2011) showed that bond valence approach is to be applied to stability prediction of tourmaline structure with different chemical composition. Using this approach we considered bond valence constraints on occupation of Y, Z, V and W sites of Cu-, Ni-bearing tourmalines. From the standpoint of the bond valence approach, [3YW] unit is unstable if W site is fully occupied by O2-. The stability of [3YW] unit decreases along a row: 3 divalent cations → 2 divalent cations + 1 trivalent cation → 2 trivalent cation + 1 divalent cations → 3 trivalent cations if W site is fully occupied by OH- or F-. There is no limitation on 3d elements and aluminum content in [2ZYV] if V site is fully occupied by OH-. The [2ZYV] unit is unstable if V site is fully occupied by O2-. The data, obtained from calculation of bond valences are in a good agreement with results of single crystal structure refinements of synthetic Cu- (Ertl et al., 2013) and Ni-tourmalines: Cu-bearing olenite with a CuO content of 8.39 wt.% [a = 15.849(1), c =7.087(1) Å, R = 2.5%] and Ni-bearing olenite with a NiO content of 18.96 wt.% [a = 15.890(2), c = 7.1815(8), R = 3.1%]. In all cases W and V sites are predominantly occupied by OH- anions. The composition of [3YW] units are [(Cu1.80Al1.20)(OH)0.60F0.40] and [(Ni1.80Al1.20)(OH)1.00]. Breaking of charge balance with increasing of bivalent cations is maintained by increasing of portion of vacancies at X site and increasing of content of trivalent cations (Al, B) at T site.

scholarly journals The study of stability of the ferric oxide sols by zeta /ζ/ potential

2014 ◽  
Vol 15 ◽  
pp. 85-88
Author(s):  
D Bayarmaa ◽  
Kh Khureltogoo
Keyword(s):  
Ferric Oxide ◽  
Ζ Potential ◽  
Membrane Filters ◽  
Zeta Potentials ◽  
The Stability ◽  
Electrolyte Ph

In this study ferric oxide sols solutions were prepared in presence of different electrolyte and their zeta potentials were measured by simplified electrophoreses method with protective semi membrane filters. The stability of these sols solution was affected by particles size and electrolyte pH. DOI: http://doi.dx.org/10.5564/mjc.v15i0.329 Mongolian Journal of Chemistry 15 (41), 2014, p85-88

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