Determination of the Nickel/Nickel Oxide Phase Transition and Henry's Constant in Hydrogenated Subcritical and Supercritical Water

2014 ◽  
Vol 162 (1) ◽  
pp. C35-C41 ◽  
Author(s):  
T. Moss ◽  
G. S. Was
Keyword(s):  
Phase Transition ◽  
Nickel Oxide ◽  
Supercritical Water ◽  
Oxide Phase ◽  
Henry's Constant

Simultaneous determination of ultra-trace Pt, Pd, Rh and Ir in geochemical samples by inductively coupled plasma mass spectrometry following tin fire assay preconcentration and microwave digestion

2020 ◽  
Vol 16 ◽  
Author(s):  
Wenshan Ni ◽  
Xiangju Mao ◽  
Hongli Zhang ◽  
Lu Liu ◽  
Xiaorui Guo ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Nickel Oxide ◽  
Inductively Coupled Plasma ◽  
Lead Oxide ◽  
Microwave Digestion ◽  
Fire Assay ◽  
Inductively Coupled ◽  
Plasma Mass Spectrometry ◽  
Ultra Trace

Background: Platinum (Pt), palladium (Pd), rhodium (Rh) and iridium (Ir) are platinum group elements (PGEs) and also important elements of geochemistry and environmental chemistry with the similar physic-chemical properties, which have been widely used in industry and laboratory. However, due to the low abundance and inhomogeneous distribution in natural ore as well as the nugget effect, the accurate determination of PGEs has been a challenge to analytical chemistry. Methods: In this work, a novel fire assay method was reported for the determination of ultra-trace Pt, Pd, Rh and Ir in geochemical samples. Tin powder (Sn) instead of stannic oxide (SnO2) was used as fire assay collector to reduce the melting temperature from 1250 oC to 1050 oC, the escape of molten material caused by high temperature was successfully avoided. Tin bead was compressed into thin slice and dissolved by HCl. For the target Pt, Pd, Rh and Ir, HCl insoluble substance such as PtSn4, PdSn4, RhSn4 and Ir3Sn7 were formed and separated from matrix by filtering. The metal compounds precipitate together with filter paper were microwave-assisted completely digested by aqua regia (50%, v/v), thence the sample solution were determined by inductively coupled plasma mass spectrometry (ICP-MS). Results: Compared with nickel oxide and lead oxide in nickel sulfide /lead fire assay, the reagent blank of tin powder were relatively low and could be directly employed in tin fire assay to collect Pt, Pd, Rh and Ir without purifying. Moreover, the harm of nickel oxide and lead oxide to the analyst and environment was avoided by using the non-toxic tin powder. The decomposition method of chromite and black shale were investigated as well as the amount of tin powder and flour, microwave digestion program for the determination of Pt, Pd, Rh and Ir were optimized. Besides, the influence of mass spectrum interference of co-existing elements was discussed and the standard mode and kinetic energy discrimination collision pool mode were compared. Under the optimal conditions, excellent curve fitting of Pt, Pd, Rh and Ir were obtained between 0.01～100 ng mL-1 , with the correlation coefficients exceeding 0.9996. The detection limits were from 0.003 ng g -1 to 0.057 ng g -1 . Conclusion: The developed method was applied to analyze the Chinese Certified Reference Materials and the determined values were in good agreement with the certified values.

scholarly journals Implications of the iron oxide phase transition on the interiors of rocky exoplanets

2021 ◽  
Author(s):  
F. Coppari ◽  
R. F. Smith ◽  
J. Wang ◽  
M. Millot ◽  
D. Kim ◽  
...  
Keyword(s):  
Phase Transition ◽  
Iron Oxide ◽  
Oxide Phase ◽  
Iron Oxide Phase

Determination of ferroelastic phase transition temperature in BiVO4 by Raman spectroscopy

2021 ◽  
Vol 291 ◽  
pp. 129519
Author(s):  
Yuwaraj K. Kshetri ◽  
Bina Chaudhary ◽  
Takashi Kamiyama ◽  
Tae-Ho Kim ◽  
Federico Rosei ◽  
...  
Keyword(s):  
Phase Transition ◽  
Raman Spectroscopy ◽  
Transition Temperature ◽  
Phase Transition Temperature ◽  
Ferroelastic Phase Transition

Determination of Size Effects during the Phase Transition of a Nanoscale Au-Si Eutectic

2009 ◽  
Vol 103 (15) ◽  
Author(s):  
B. J. Kim ◽  
J. Tersoff ◽  
C.-Y. Wen ◽  
M. C. Reuter ◽  
E. A. Stach ◽  
...  
Keyword(s):  
Phase Transition ◽  
Size Effects

A NUCLEAR MANY-BODY THEORY AT FINITE TEMPERATURE APPLIED TO A PROTONEUTRON STAR

2002 ◽  
Vol 11 (02) ◽  
pp. 83-104 ◽  
Author(s):  
GUILHERME F. MARRANGHELLO ◽  
CESAR A. Z. VASCONCELLOS ◽  
MANFRED DILLIG ◽  
J. A. DE FREITAS PACHECO
Keyword(s):  
Phase Transition ◽  
Nuclear Matter ◽  
Finite Temperature ◽  
Degrees Of Freedom ◽  
Many Body ◽  
Many Body Theory ◽  
The Masses ◽  
Protoneutron Stars ◽  
Protoneutron Star

Thermodynamical properties of nuclear matter are studied in the framework of an effective many-body field theory at finite temperature, considering the Sommerfeld approximation. We perform the calculations by using the nonlinear Boguta and Bodmer model, extended by the inclusion of the fundamental baryon octet and leptonic degrees of freedom. Trapped neutrinos are also included in order to describe protoneutron star properties through the integration of the Tolman–Oppenheimer–Volkoff equations, from which we obtain, beyond the standard relations for the masses and radii of protoneutron stars as functions of the central density, new results of these quantities as functions of temperature. Our predictions include: the determination of an absolute value for the limiting mass of protoneutron stars; new structural aspects on the nuclear matter phase transition via the behavior of the specific heat and, through the inclusion of quark degrees of freedom, the properties of a hadron-quark phase transition and hybrid protoneutron stars

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