scholarly journals Phase transition and equation of state of dense hydrous silica up to 63 GPa

2017 ◽  
Vol 122 (9) ◽  
pp. 6972-6983 ◽  
Author(s):  
C. Nisr ◽  
K. Leinenweber ◽  
V. Prakapenka ◽  
C. Prescher ◽  
S. Tkachev ◽  
...  
Keyword(s):  
Phase Transition ◽  
Equation Of State ◽  
Hydrous Silica

Equation of State and Phase Transition of the Spherical Lattice Gas

1960 ◽  
Vol 120 (1) ◽  
pp. 22-32 ◽  
Author(s):  
Walter Pressman ◽  
Joseph B. Keller
Keyword(s):  
Phase Transition ◽  
Equation Of State ◽  
Lattice Gas

Equation of state and phase transition of antigorite under high pressure and high temperature

2014 ◽  
Vol 228 ◽  
pp. 56-62 ◽  
Author(s):  
Cuiping Yang ◽  
Toru Inoue ◽  
Akihiro Yamada ◽  
Takumi Kikegawa ◽  
Jun-ichi Ando
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
High Temperature ◽  
Equation Of State

scholarly journals Constraints on the hybrid equation of state with a crossover hadron-quark phase transition in the light of GW170817

2018 ◽  
Vol 98 (8) ◽  
Author(s):  
Cheng-Ming Li ◽  
Yan Yan ◽  
Jin-Jun Geng ◽  
Yong-Feng Huang ◽  
Hong-Shi Zong
Keyword(s):  
Phase Transition ◽  
Equation Of State ◽  
Quark Phase

scholarly journals Equation-of-state constraints and the QCD phase transition in the era of gravitational-wave astronomy

2019 ◽  
Author(s):  
Andreas Bauswein ◽  
Niels-Uwe Friedrich Bastian ◽  
David Blaschke ◽  
Katerina Chatziioannou ◽  
James Alexander Clark ◽  
...  
Keyword(s):  
Phase Transition ◽  
Equation Of State ◽  
Gravitational Wave ◽  
State Constraints ◽  
Qcd Phase Transition

scholarly journals Construction of a Universal Gel Model with Volume Phase Transition

Gels ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 7
Author(s):  
Gerald S. Manning
Keyword(s):  
Phase Transition ◽  
Critical Temperature ◽  
Equation Of State ◽  
Chemical Potential ◽  
Van Der Waals ◽  
Density Fluctuations ◽  
Volume Phase Transition ◽  
Restoring Force ◽  
Intrinsic Volume ◽  
Volume Phase

The physical principle underlying the familiar condensation transition from vapor to liquid is the competition between the energetic tendency to condense owing to attractive forces among molecules of the fluid and the entropic tendency to disperse toward the maximum volume available as limited only by the walls of the container. Van der Waals incorporated this principle into his equation of state and was thus able to explain the discontinuous nature of condensation as the result of instability of intermediate states. The volume phase transition of gels, also discontinuous in its sharpest manifestation, can be understood similarly, as a competition between net free energy attraction of polymer segments and purely entropic dissolution into a maximum allowed volume. Viewed in this way, the gel phase transition would require nothing more to describe it than van der Waals’ original equation of state (with osmotic pressure Π replacing pressure P). But the polymer segments in a gel are networked by cross-links, and a consequent restoring force prevents complete dissolution. Like a solid material, and unlike a van der Waals fluid, a fully swollen gel possesses an intrinsic volume of its own. Although all thermodynamic descriptions of gel behavior contain an elastic component, frequently in the form of Flory-style rubber theory, the resulting isotherms usually have the same general appearance as van der Waals isotherms for fluids, so it is not clear whether the solid-like aspect of gels, that is, their intrinsic volume and shape, adds any fundamental physics to the volume phase transition of gels beyond what van der Waals already knew. To address this question, we have constructed a universal chemical potential for gels that captures the volume transition while containing no quantities specific to any particular gel. In this sense, it is analogous to the van der Waals theory of fluids in its universal form, but although it incorporates the van der Waals universal equation of state, it also contains a network elasticity component, not based on Flory theory but instead on a nonlinear Langevin model, that restricts the radius of a fully swollen spherical gel to a solid-like finite universal value of unity, transitioning to a value less than unity when the gel collapses. A new family of isotherms arises, not present in a preponderately van der Waals analysis, namely, profiles of gel density as a function of location in the gel. There is an abrupt onset of large amplitude density fluctuations in the gel at a critical temperature. Then, at a second critical temperature, the entire swollen gel collapses to a high-density phase.

The deformation mechanism of a pressure-induced phase transition in dehydrated analcime

2012 ◽  
Vol 76 (1) ◽  
pp. 129-142 ◽  
Author(s):  
A. Yu. Likhacheva ◽  
S. V. Rashchenko ◽  
Yu. V. Seryotkin
Keyword(s):  
Phase Transition ◽  
Equation Of State ◽  
Structure Type ◽  
Elastic Behaviour ◽  
Structural Behaviour ◽  
Synchrotron Powder Diffraction ◽  
First Order Phase Transition ◽  
Diamond Anvil ◽  
First Order Phase ◽  
Murnaghan Equation

AbstractThe elastic and structural behaviour of dehydrated analcime in compression in a non-penetrating medium up to 3 GPa was studied in a diamond anvil cell using in situ synchrotron powder diffraction. A first-order phase transition at 0.4–0.7 GPa is accompanied by a symmetry change from monoclinic (I2/a) to pseudo-rhombohedral (R3) due to trigonalization of the aluminosilicate framework. This is due to the migration of cations to new positions close to the 6-membered rings forming the channels. The reduction of the mean aperture of the structure-forming 6- and 8-membered rings, as a result of tetrahedral tilting, leads to a 7.5% reduction in volume at the phase transition. The bulk modulus values are 38(2) GPa for the low pressure (LP) phase [fitted with a Murnaghan equation of state, K' = 4 (fixed)] and 11(4) GPa for the high pressure (HP) phase [fitted with a third-order Birch–Murnaghan equation of state, K' = 9(1)]. The elastic behaviour of the LP phase is anisotropic, with compressibilities βa:βb:βc in the ratio 1:4:2; the most compressible direction b coinciding with the orientation of empty 8-membered rings. The compressibility of the HP phase is isotropic. Trigonalization appears to be the most effective (and probably unique) mechanism of radical volume contraction for the ANA structure type.

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