scholarly journals Response of the Surface Phase Transition to an Abrupt Pressure Change: Comparative Study of the 2D Gas–Liquid and 2D Fluid–Solid Phase Transitions

1998 ◽  
Vol 16 (5) ◽  
pp. 391-404 ◽  
Author(s):  
Yosihito Kitayama ◽  
Yosinobll Sakai ◽  
Hiromu Asada
Keyword(s):  
Phase Transition ◽  
Liquid Phase ◽  
Time Constant ◽  
Solid Phase ◽  
Pressure Change ◽  
Fast Decay ◽  
Liquid Phase Transition ◽  
Decay Component ◽  
Slow Decay ◽  
Solid Phase Transition

The manner in which gaseous CH4 and N2 respond to an abrupt pressure change through adsorption and desorption on exfoliated graphite held at a temperature between 77 K and 90 K has been studied with particular emphasis on the role of the 2D (two-dimensional) Gas–Liquid phase transition of the second layer of adsorbed CH4 and of the 2D Fluid–Solid phase transition of adsorbed N2. The pressure relaxation was found to consist of two exponential decay components: a fast one and a slow one. For CH4, the 2D Gas–Liquid phase transition is involved in the fast decay component with a time constant of 2–3 s, while the slow decay component with a time constant of 7–40 s is minor and has been attributed to ripening or coalescence processes in the adsorbed phase. In contrast, the 2D Fluid–Solid phase transition of N2 involves both the fast decay component with a time constant of 2–3 s and the slow decay component with a time constant of 14–16 s, both having nearly equal magnitudes. The difference in the pressure response between the two phase transitions is discussed.

n-pentanol at high pressures: Rotational isomerism in the liquid phase and the liquid-solid phase transition

2006 ◽  
Vol 124 (4) ◽  
pp. 044508 ◽  
Author(s):  
V. G. Baonza ◽  
M. Taravillo ◽  
A. Cazorla ◽  
S. Casado ◽  
M. Cáceres
Keyword(s):  
Phase Transition ◽  
Liquid Phase ◽  
High Pressures ◽  
Solid Phase ◽  
Rotational Isomerism ◽  
Solid Phase Transition

scholarly journals Liquid-liquid phase separation of full-length prion protein initiates conformational conversion in vitro

2020 ◽  
Author(s):  
Hiroya Tange ◽  
Daisuke Ishibashi ◽  
Takehiro Nakagaki ◽  
Yuzuru Taguchi ◽  
Yuji O. Kamatari ◽  
...  
Keyword(s):  
Phase Transition ◽  
Phase Separation ◽  
Liquid Phase ◽  
Prion Protein ◽  
Solid Phase ◽  
Terminal Region ◽  
Liquid Phase Separation ◽  
Solid Phase Transition ◽  
Liquid Liquid Phase Separation

AbstractPrion diseases are characterized by accumulation of amyloid fibrils. The causative agent is an infectious amyloid that is comprised solely of misfolded prion protein (PrPSc). Prions can convert PrPC to proteinase-resistant PrP (PrP-res) in vitro; however, the intermediate steps involved in the spontaneous conversion remain unknown. We investigated whether recombinant prion protein (rPrP) can directly convert into PrP-res via liquid-liquid phase separation in the absence of PrPSc. We found that rPrP underwent liquid-liquid phase separation at the interface of the aqueous two-phase system (ATPS) of polyethylene glycol (PEG) and dextran, whereas single-phase conditions were not inducible. Fluorescence recovery assay after photobleaching revealed that the liquid-solid phase transition occurred within a short time. The aged rPrP-gel acquired proteinase-resistant amyloid accompanied by β-sheet conversion, as confirmed by western blotting, Fourier transform infrared spectroscopy, and Congo red staining. The reactions required both the N-terminal region of rPrP (amino acids 23-89) and kosmotropic salts, suggesting that the kosmotropic anions may interact with the N-terminal region of rPrP to promote liquid-liquid phase separation. Thus, structural conversion via liquid–liquid phase separation and liquid–solid phase transition are intermediate steps in the conversion of prions.

scholarly journals Sensitivity of Pore Collapse Heating to the Melting Temperature and Liquid-phase Shear Viscosity of HMX

2020 ◽  
Author(s):  
Matthew Kroonblawd ◽  
Ryan Austin
Keyword(s):  
Phase Transition ◽  
Liquid Phase ◽  
Melting Temperature ◽  
Shear Viscosity ◽  
Solid Phase ◽  
Scale Model ◽  
Pore Collapse ◽  
Liquid Phase Transition ◽  
Solid Liquid ◽  
Liquid Shear

A multiscale modeling strategy is used to quantify factors governing the temperature rise in hot spots formed by pore collapse from supported and unsupported shock waves in the high explosive HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine). Two physical aspects are examined in detail, namely the melting temperature and liquid shear viscosity. All-atom molecular dynamics simulations of phase coexistence are used to predict the pressure-dependent melting temperature up to 5~GPa. Equilibrium simulations and the Green-Kubo formalism are used to obtain the temperature- and pressure-dependent liquid shear viscosity. Starting from a simplified continuum-based grain-scale model for HMX, we systematically increase the complexity of treatments for the solid-liquid phase transition and liquid shear viscosity in simulations of pore collapse. Using a realistic pressure-dependent melting temperature completely suppresses melting for supported shocks, which is otherwise predicted when treating it as a constant determined at atmospheric pressure. Alternatively, large melt pools form around pores during pressure release in unsupported shocks, even with a pressure-dependent melting temperature. Capturing the pressure dependence of the shear viscosity increases the peak temperature of melt pools by hundreds of Kelvin through viscous work. The complicated interplay of the solid-phase plastic work, solid-liquid phase transition, and liquid-phase viscous work identified here motivate taking a systematic approach to building increasingly complex grain-scale models and for guiding interpretation of predictions made using them.

scholarly journals The Stefan problem in a thermomechanical context with fracture and fluid flow

2021 ◽  
Author(s):  
Tomáš Roubíček
Keyword(s):  
Phase Transition ◽  
Liquid Phase ◽  
Stefan Problem ◽  
Solid Phase ◽  
Phase Field Model ◽  
Liquid Phase Transition ◽  
Time Discretisation ◽  
Eulerian Description ◽  
Solid Liquid ◽  
Viscoelastic Rheology

The classical Stefan problem, concerning mere heat-transfer during solid-liquid phase transition, is here enhanced towards mechanical effects. The Eulerian description at large displacements is used with convective and Zaremba-Jaumann corotational time derivatives, linearized by exploiting the additive Green-Naghdi’s decomposition in (objective) rates. In particular, the liquid phase is a viscoelastic fluid while creep and rupture of the solid phase is considered in the Jeffreys viscoelastic rheology exploiting the phase-field model, exploiting a concept of slightly (so-called “semi”) compressible materials. The $L^1$-theory for the heat equation is adopted for the Stefan problem relaxed by allowing for kinetic superheating/supercooling effects during the solid-liquid phase transition. A rigorous proof of existence of week solutions is provided for an incomplete melting, exploiting a time-discretisation approximation.

Sensitivity of Pore Collapse Heating to the Melting Temperature and Liquid-phase Shear Viscosity of HMX

2020 ◽  
Author(s):  
Matthew Kroonblawd ◽  
Ryan Austin
Keyword(s):  
Phase Transition ◽  
Liquid Phase ◽  
Melting Temperature ◽  
Shear Viscosity ◽  
Solid Phase ◽  
Scale Model ◽  
Pore Collapse ◽  
Liquid Phase Transition ◽  
Solid Liquid ◽  
Liquid Shear

A multiscale modeling strategy is used to quantify factors governing the temperature rise in hot spots formed by pore collapse from supported and unsupported shock waves in the high explosive HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine). Two physical aspects are examined in detail, namely the melting temperature and liquid shear viscosity. All-atom molecular dynamics simulations of phase coexistence are used to predict the pressure-dependent melting temperature up to 5~GPa. Equilibrium simulations and the Green-Kubo formalism are used to obtain the temperature- and pressure-dependent liquid shear viscosity. Starting from a simplified continuum-based grain-scale model for HMX, we systematically increase the complexity of treatments for the solid-liquid phase transition and liquid shear viscosity in simulations of pore collapse. Using a realistic pressure-dependent melting temperature completely suppresses melting for supported shocks, which is otherwise predicted when treating it as a constant determined at atmospheric pressure. Alternatively, large melt pools form around pores during pressure release in unsupported shocks, even with a pressure-dependent melting temperature. Capturing the pressure dependence of the shear viscosity increases the peak temperature of melt pools by hundreds of Kelvin through viscous work. The complicated interplay of the solid-phase plastic work, solid-liquid phase transition, and liquid-phase viscous work identified here motivate taking a systematic approach to building increasingly complex grain-scale models and for guiding interpretation of predictions made using them.

scholarly journals Electrically Induced Liquid–Liquid Phase Transition in a Floating Water Bridge Identified by Refractive Index Variations

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 602
Author(s):  
Elmar C. Fuchs ◽  
Jakob Woisetschläger ◽  
Adam D. Wexler ◽  
Rene Pecnik ◽  
Giuseppe Vitiello
Keyword(s):  
Phase Transition ◽  
Refractive Index ◽  
Liquid Phase ◽  
Pure Water ◽  
Resonance Effect ◽  
Water Bridge ◽  
Liquid Phase Transition ◽  
Light Passing ◽  
Floating Water Bridge ◽  
Set Up

A horizontal electrohydrodynamic (EHD) liquid bridge (also known as a “floating water bridge”) is a phenomenon that forms when high voltage DC (kV·cm−1) is applied to pure water in two separate beakers. The bridge, a free-floating connection between the beakers, acts as a cylindrical lens and refracts light. Using an interferometric set-up with a line pattern placed in the background of the bridge, the light passing through is split into a horizontally and a vertically polarized component which are both projected into the image space in front of the bridge with a small vertical offset (shear). Apart from a 100 Hz waviness due to a resonance effect between the power supply and vortical structures at the onset of the bridge, spikes with an increased refractive index moving through the bridge were observed. These spikes can be explained by an electrically induced liquid–liquid phase transition in which the vibrational modes of the water molecules couple coherently.

scholarly journals Two-state thermodynamics and the possibility of a liquid-liquid phase transition in supercooled TIP4P/2005 water

2016 ◽  
Vol 144 (14) ◽  
pp. 144504 ◽  
Author(s):  
Rakesh S. Singh ◽  
John W. Biddle ◽  
Pablo G. Debenedetti ◽  
Mikhail A. Anisimov
Keyword(s):  
Phase Transition ◽  
Liquid Phase ◽  
Liquid Phase Transition
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