Dissociative Phase Transitions, Split Shock Waves, Rarefaction Shocks, and Detonations

1992 ◽  
Vol 296 ◽  
Author(s):  
C. T. White ◽  
D. H. Robertson ◽  
M. L. Elert ◽  
J. W. Mintmire ◽  
D. W. Brenner
Keyword(s):  
Phase Transition ◽  
Shock Waves ◽  
Comparative Study ◽  
Continuum Theory ◽  
The Other ◽  
Polymorphic Phase Transition ◽  
Von Neumann ◽  
First Order ◽  
First Order Phase Transition ◽  
First Order Phase

AbstractWe present a comparative study of two different chemically-sustained shock waves. One shows behavior expected from the Zel'dovich, von Neumann, and Doering (ZND) continuum theory of planar detonations. The other exhibits the complexity of a split shock wave resulting from the presence of a polymorphic phase transition. This comparative study demonstrates the importance of carefully considering the high-pressure characteristics of the model in developing potentials for simulating detonations. This comparative study also raises the fascinating possibility of a first-order phase transition accompanying a condensed-phase detonation.

FIRST ORDER PHASE TRANSITIONS, WHEN AND FROM WHERE DO THEY EMERGE? —THE CASE OF GELS

1995 ◽  
Vol 09 (07) ◽  
pp. 737-749 ◽  
Author(s):  
KEN SEKIMOTO
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Transition Point ◽  
The Other ◽  
Basic Fact ◽  
Theoretical Understanding ◽  
First Order ◽  
First Order Phase Transition ◽  
The One ◽  
First Order Phase

We briefly review the recent theoretical understanding of the first order phase transition undergone by gels with an emphasis on physical concepts, deliberately excluding details of modeling and analytic methods. The density of a gel changes discontinuously at the transition point. A variety of features of the transition result from the basic fact that the inhomogeneity of the density of the gel inevitably causes shear deformation. This deformation, on the one hand, reflects the geometry of the sample and, on the other hand, may alter the transition temperature.

scholarly journals Microscopic Model of Intermediate Phase in Flexible to Rigid Transition

2021 ◽  
Vol 8 ◽  
Author(s):  
Aldo Sayeg Pasos-Trejo ◽  
Atahualpa S. Kraemer
Keyword(s):  
Phase Transition ◽  
Order Phase Transition ◽  
Chalcogenide Glasses ◽  
Lattice Gas ◽  
Chemical Potential ◽  
Intermediate Phase ◽  
The Other ◽  
First Order ◽  
First Order Phase Transition ◽  
First Order Phase

We introduce a lattice gas model with a modified Hamiltonian considering different energy for cycles of connected atoms. The system can be interpreted as a chalcogenide glass with pollutants forming floppy and rigid structures. We consider an energetic penalization for redundant bonds in the network. This penalization allows us to incorporate the topology constraints of rigidity in the network to study the thermodynamics of the system. We observe, depending on the parameter used for the penalization, that the system exhibits a typical first-order phase transition, or a stepped transition between the low and high density while varying the chemical potential. We also observe a hysteresis loop in the density and energy of the system. We use the area of these loops to calculate the irreversible enthalpy. There are two regimes, one where the enthalpy decreases linearly and the other with almost constant enthalpy. As the enthalpy is almost constant and very low, we interpreted this as the intermediate phase of the chalcogenide glasses.

Structure and Phase Transition in (C2H5NH3)3Sb2Cl9 · (C2H5NH3)SbCl4 ; X-ray, DSC and Dielectric Studies

2000 ◽  
Vol 55 (5) ◽  
pp. 526-532 ◽  
Author(s):  
Maciej Bujak ◽  
Jacek Zaleski
Keyword(s):  
Phase Transition ◽  
The Other ◽  
Dielectric Studies ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
First Order ◽  
First Order Phase Transition ◽  
First Order Phase ◽  
Disorder Type

Abstract The structure of (C2H5NH3)3Sb2Cl9 • (C2H5NH3)SbCl4 at 295 K has been determined. The crystals are orthorhombic, space group Pna21 (a -16.925(3), b = 24.703(5), c = 7.956(2) Å, V = 3326.4(12) Å3 , Z = 4, dc= 2.018, dm= 2.01(1) Mg m-3). They consist of an anionic sublattice composed of two different polymeric zig-zag chains. One is built of Sb2Cl93- units (corner sharing octahedra) and the other one is made of corner sharing SbCl52-square pyramids. In the cavites between the polyanionic chains four non-equivalent ethylammonium cations are located. Three of them are disordered. The cations are connected to the anions by weak N-H...Cl hydrogen bonds. A first order phase transition of the order-disorder type was found at 274 K. It was studied by DSC, dielectric and X-ray diffraction methods. The mechanism of the phase transition is attributed to the ordering of at least one of the ethylammonium cations

First order phase transition of Li3ThF7at 281 K: A comparative study between EPR and Raman scattering

2001 ◽  
Vol 155 (1-4) ◽  
pp. 361-366 ◽  
Author(s):  
K. Krambrock ◽  
K. J. Guedes ◽  
M. V. B. Pinheiro ◽  
C. J. Franco ◽  
M. A. S. Oliveira ◽  
...  
Keyword(s):  
Phase Transition ◽  
Raman Scattering ◽  
Comparative Study ◽  
Order Phase Transition ◽  
First Order ◽  
First Order Phase Transition ◽  
First Order Phase

scholarly journals Gravitational wave signals of dark matter freeze-out

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Danny Marfatia ◽  
Po-Yan Tseng
Keyword(s):  
Phase Transition ◽  
Dark Matter ◽  
Gravitational Waves ◽  
Order Phase Transition ◽  
First Order ◽  
Stochastic Background ◽  
First Order Phase Transition ◽  
Relic Abundance ◽  
First Order Phase ◽  
Freeze Out

Abstract We study the stochastic background of gravitational waves which accompany the sudden freeze-out of dark matter triggered by a cosmological first order phase transition that endows dark matter with mass. We consider models that produce the measured dark matter relic abundance via (1) bubble filtering, and (2) inflation and reheating, and show that gravitational waves from these mechanisms are detectable at future interferometers.

scholarly journals Dark Matter production from relativistic bubble walls

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Aleksandr Azatov ◽  
Miguel Vanvlasselaer ◽  
Wen Yin
Keyword(s):  
Phase Transition ◽  
Dark Matter ◽  
Electroweak Phase Transition ◽  
First Order ◽  
Matter Production ◽  
First Order Phase Transition ◽  
Relic Abundance ◽  
Higgs Portal ◽  
First Order Phase ◽  
Gravitational Background

Abstract In this paper we present a novel mechanism for producing the observed Dark Matter (DM) relic abundance during the First Order Phase Transition (FOPT) in the early universe. We show that the bubble expansion with ultra-relativistic velocities can lead to the abundance of DM particles with masses much larger than the scale of the transition. We study this non-thermal production mechanism in the context of a generic phase transition and the electroweak phase transition. The application of the mechanism to the Higgs portal DM as well as the signal in the Stochastic Gravitational Background are discussed.

Discovering a First-Order Phase Transition in the Li–CeO2 System

Nano Letters ◽  
2017 ◽  
Vol 17 (2) ◽  
pp. 1282-1288 ◽  
Author(s):  
Kaikai Li ◽  
Xiaoye Zhou ◽  
Anmin Nie ◽  
Sheng Sun ◽  
Yan-Bing He ◽  
...  
Keyword(s):  
Phase Transition ◽  
Order Phase Transition ◽  
First Order ◽  
First Order Phase Transition ◽  
First Order Phase
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