Phase Equilibria and Elements Partitioning in Zirconolite-Rich Region of Ca-Zr-Ti-Al-Gd-Si-O System

1996 ◽  
Vol 465 ◽  
Author(s):  
O. A. Knyazev ◽  
S. V. Stefanovsky ◽  
S. V. Ioudintsev ◽  
B. S. Nikonov ◽  
B. I. Omelianenko ◽  
...  
Keyword(s):  
Phase Composition ◽  
Phase Equilibria ◽  
The Other ◽  
Cold Crucible ◽  
Rich Region ◽  
Aluminium Titanate ◽  
Air Atmosphere ◽  
Melting Technique ◽  
Mineral Structure

ABSTRACTZirconolite-rich ceramics were produced by the cold crucible melting technique in an air atmosphere, at 1550±50 °C and 1 atm. Four samples with overall composition (in wt.%): 4.9–14.3 CaO; 19.0–41.3 ZrO2; 24.1–42.6 TiO2; 1.3–11.3 Al2O3; 6.8–30.0 Gd2O3, and 1.1–8.5 SiO2 have been studied. Total phases in the ceramics consist of major zirconolite and minor rutile, perovskite, zirconia, aluminium titanate, and glass. The Gd2O3 content in zirconolite reaches up to 31.4 wt.% corresponding to the formula: (Cao4,Gd0.7)Zri.0(Tii4,Alo 5)070. The data on the phase composition agree well with coupled Gd incorporation into the mineral structure. Ca(H) + Ti(IV) = Gd(III) + Al(III), and 2Gd(III) - Ca(II) + Zr(IV). The highest Gd contents observed in the other phases are 25.4 % for zirconia, 12.6 % in glass, 8.8 % in perovskite, and 1.4 % for rutile. The rest of the elements' distribution in the samples are analyzed.

scholarly journals Phase equilibria in the MnO-Mn2O3-FeO-Fe2O3-Sb2O3-Sb2O5 System in Air at 1200℃

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
BG Golovkin
Keyword(s):  
Phase Diagram ◽  
Phase Composition ◽  
Phase Equilibria ◽  
Normal Pressure ◽  
X Ray ◽  
Densitometric Analysis ◽  
Temperature Range ◽  
Air Atmosphere ◽  
Different Temperatures ◽  
New Phase

Using the methods of X-ray phase and X-ray Densitometric analysis, the phase equilibria between oxides of manganese, iron and antimony have been investigated in an air atmosphere at temperatures up to 1250? in an air mosphere at normal pressure. The phase diagram of the system at 1200? was built MnO-Mn2O3-FeO-Fe2O-Sb2O3-Sb2O5. A new phase was found Mn12-2x,sup>2+Fe2x2+Sb3+Sb55+O26(0?x?1), with edge compositions FeMn5Sb3O13 and Mn6Sb3O3 (a=8.5003?0.0025Å; b=8.0064?0.0025Å; c=11.5779?0.0025Å; Z = 3; ?obs. = 5.7 g/cm3; ?calc = 5.6991 g/cm3). The phase exists in the temperature range 1180-1230oC and can be obtained by quenching, but always with a large admixture of Mn2Sb2O7 and spinel Mn112+Mn133+Sb93+O44.The reason for this behavior is that air molecules have different temperatures, as a result of which the phase composition of the reaction mixture cannot be strictly related to one temperature, and different phases can be stable at different temperatures.

The Al-rich region in the Y–Ni–Al system: microstructures and phase equilibria

2000 ◽  
Vol 8 (3) ◽  
pp. 247-257 ◽  
Author(s):  
Riccardo Raggio ◽  
Gabriella Borzone ◽  
Riccardo Ferro
Keyword(s):  
Phase Equilibria ◽  
Rich Region

Phase equilibria in Ni-rich region of Ni–Al–Hf system

Metal Science ◽  
1981 ◽  
Vol 15 (8) ◽  
pp. 347-352 ◽  
Author(s):  
P. Nash ◽  
D. R. F. West
Keyword(s):  
Phase Equilibria ◽  
Rich Region

scholarly journals Phase Equilibria in the Nb-Rich Region of Al-Nb-Sn at 900 and 1200 °C

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2759 ◽  
Author(s):  
Ioannis Papadimitriou ◽  
Claire Utton ◽  
Panos Tsakiropoulos
Keyword(s):  
Crystal Structure ◽  
Phase Equilibria ◽  
Ternary Phase ◽  
X Ray Diffraction ◽  
High Solubility ◽  
Rich Region ◽  
X Ray ◽  
Heat Treated ◽  
Aero Engine ◽  
Scanning Electron

The Al-Nb-Sn phase diagram was studied experimentally in the Nb-rich region to provide important phase equilibria information for alloy design of Nb-silicide based materials for aero engine applications. Three alloys were produced: Nb-17Al-17Sn, Nb-33Al-13Sn and Nb-16Al-20Sn (at.%). As-cast and heat-treated alloys (900 and 1200 °C) were analysed using XRD (X-ray diffraction) and SEM/EDS (scanning electron microscopy/ electron dispersive x-ray spectroscopy). Tin showed a high solubility in Nb2Al, reaching up to 21 at.% in the Sn-rich areas, substituting for Al atoms. Tin and Al also substituted for each other in the A15 phases (Nb3Al and Nb3Sn). Tin showed limited solubility in NbAl3, not exceeding 3.6 at.% as it substituted Al atoms. The solubility of Al in NbSn2 varied from 4.8 to 6.8 at.%. A ternary phase, Nb5Sn2Al with the tI32 W5Si3 crystal structure, was found to be stable. This phase was observed in the 900 °C heat-treated samples, but not in the 1200 °C heated samples.

Accommodation of Uranium into the Garnet Structure

2002 ◽  
Vol 713 ◽  
Author(s):  
Sergey V. Yudintsev ◽  
Marya I. Lapina ◽  
Alexander G. Ptashkin ◽  
Tatiana S. Ioudintseva ◽  
Satoshi Utsunomiya ◽  
...  
Keyword(s):  
Phase Composition ◽  
Ion Irradiation ◽  
High Capacity ◽  
Heavy Ion ◽  
Uranium Content ◽  
The Other ◽  
Garnet Structure ◽  
Heavy Ion Irradiation ◽  
Si Doped ◽  
Air Medium

ABSTRACTOne promising host for actinide wastes is garnet-type phases of general formula AVIII3BVI 2[XO4]3. To determine the isomorphic capacity of garnet for uranium, the CaO – Fe2O3 – Al2O3 – SiO2 – ZrO2 – Gd2O3 – UO2 system was studied. Experiments were performed in air medium at 1400 – 1500 °C and 1 atm. The garnets have high capacity for Gd and Zr, while incorporation of U was found to be greatly dependent on the phase composition. Uranium content decreased from 18 wt.% in Ca-Zr-Fe garnet to 0.6 wt.% in Si-doped phases. Heavy ion irradiation (1.0 MeV Kr++) experiments were carried out for a garnet with maximal U content, (Ca2.7U0.3)VIII(Zr1.7Fe0.3)VI(Al1.1Fe1.9)IVO12. Amorphization dose of the phase was equal to 1.63×1014 ions/cm2 that is close to the other actinide hosts, such as pyrochlore Gd2Ti2O7.

The presence of an ER exit signal determines the protein sorting upon ER exit in yeast

2008 ◽  
Vol 414 (2) ◽  
pp. 237-245 ◽  
Author(s):  
Reika Watanabe ◽  
Guillaume A. Castillon ◽  
Anja Meury ◽  
Howard Riezman
Keyword(s):  
Endoplasmic Reticulum ◽  
Protein Sorting ◽  
Surface Protein ◽  
The Other ◽  
Gpi Anchor ◽  
Rich Region ◽  
Characteristic Features ◽  
Detergent Resistant Membrane

In yeast, there are at least two vesicle populations upon ER (endoplasmic reticulum) exit, one containing Gap1p (general aminoacid permease) and a glycosylated α-factor, gpαF (glycosylated proα-factor), and the other containing GPI (glycosylphosphatidylinositol)-anchored proteins, Gas1p (glycophospholipid-anchored surface protein) and Yps1p. We attempted to identify sorting determinants for this protein sorting event in the ER. We found that mutant Gas1 proteins that lack a GPI anchor and/or S/T region (serine- and threonine-rich region), two common characteristic features conserved among yeast GPI-anchored proteins, were still sorted away from Gap1p-containing vesicles. Furthermore, a mutant glycosylated α-factor, gpαGPI, which contains both the GPI anchor and S/T region from Gas1p, still entered Gap1p-containing vesicles, demonstrating that these conserved characteristics do not prevent proteins from entering Gap1p-containing vesicles. gpαF showed severely reduced budding efficiency in the absence of its ER exit receptor Erv29p, and this residual budding product no longer entered Gap1p-containing vesicles. These results suggest that the interaction of gpαF with Erv29p is essential for sorting into Gap1p-containing vesicles. We compared the detergent solubility of Gas1p and the gpαGPI in the ER with that in ER-derived vesicles. Both GPI-anchored proteins similarly partitioned into the DRM (detergent-resistant membrane) in the ER. Based on the fact that they entered different ER-derived vesicles, we conclude that DRM partitioning of GPI-anchored proteins is not the dominant determinant of protein sorting upon ER exit. Interestingly, upon incorporation into the ER-derived vesicles, gpαGPI was no longer detergent-insoluble, in contrast with the persistent detergent insolubility of Gas1p in the ER-derived vesicles. We present different explanations for the different behaviours of GPI-anchored proteins in distinct ER-derived vesicle populations.

Study on the Phase Formation of Corundum-Type Mg4Nb2O9 Powders by the Solid-State Process

2012 ◽  
Vol 499 ◽  
pp. 174-177
Author(s):  
Yi Shan Jiang ◽  
Ying Zi Wang ◽  
Ya Ming Chen ◽  
Yun Long Yue ◽  
Hai Tao Wu
Keyword(s):  
Phase Composition ◽  
Solid State ◽  
Phase Formation ◽  
Single Phase ◽  
Magnesium Niobate ◽  
Calcination Temperatures ◽  
Air Atmosphere ◽  
State Process

The corundum-type magnesium niobate, Mg4Nb2O9, powders were synthesized by the conventional solid-state process. The mixtures of MgO and Nb2O5were calcined in the temperature ranging from 500°C to 1200°C for crystallization in air atmosphere. The formation of the Mg4Nb2O9phase was investigated as a function of calcination temperatures by DTA and XRD. The morphology and phase composition were determined via a combination of SEM and EDX techniques. The results showed that the single-phase Mg4Nb2O9could be obtained at 1050°C for 2h with the size of less than 5μm.

Phase equilibria in Co-rich region of Co-Ti-Ta system

2011 ◽  
Vol 21 (11) ◽  
pp. 2391-2395 ◽  
Author(s):  
Min JIANG ◽  
Gerile SAREN ◽  
Su-yu YANG ◽  
Hong-xiao LI ◽  
Shi-ming HAO
Keyword(s):  
Phase Equilibria ◽  
Rich Region

Mitochondrial DNA variation in Drosophila pseudoobscura and related species in Pacific Northwest populations

1985 ◽  
Vol 27 (3) ◽  
pp. 357-364 ◽  
Author(s):  
Lawrence R. Hale ◽  
Andrew T. Beckenbach
Keyword(s):  
Mitochondrial Dna ◽  
Pacific Northwest ◽  
Restriction Enzymes ◽  
The Other ◽  
Drosophila Pseudoobscura ◽  
Rich Region ◽  
Dna Variation ◽  
Restriction Sites ◽  
Dna Restriction ◽  
Tandem Duplications

We have analysed mitochondrial DNA (mtDNA) from Pacific Northwest populations of Drosophila pseudoobscura, D. persimilis, and D. miranda using six restriction enzymes. We find that HpaII restriction sites are hypervariable compared to the other enzymes used. This hypervariability allows construction of a maximum parsimony map linking each mtDNA genotype. Small insertions, possibly tandem duplications, appear to have arisen concomitantly with, or subsequent to, speciation events, perhaps within the A + T rich region. Convergence of mtDNA genotypes is also evident. Unlike findings for other populations of these species, we find little evidence of mitochondrial introgression between D. pseudoobscura and D. persimilis, despite their ability to produce fertile hybrid females.Key words: mitochondrial DNA, restriction endonucleases, Drosophila, evolution.

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