scholarly journals Manifestations of metastable criticality in the long-range structure of model water glasses

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Thomas E. Gartner ◽  
Salvatore Torquato ◽  
Roberto Car ◽  
Pablo G. Debenedetti
Keyword(s):  
Phase Behavior ◽  
Critical Point ◽  
Long Range ◽  
Metastable Phase ◽  
Density Fluctuations ◽  
Model Systems ◽  
Metastable Equilibrium ◽  
Pronounced Increase ◽  
Liquid Transition ◽  
Non Equilibrium

AbstractMuch attention has been devoted to water’s metastable phase behavior, including polyamorphism (multiple amorphous solid phases), and the hypothesized liquid-liquid transition and associated critical point. However, the possible relationship between these phenomena remains incompletely understood. Using molecular dynamics simulations of the realistic TIP4P/2005 model, we found a striking signature of the liquid-liquid critical point in the structure of water glasses, manifested as a pronounced increase in long-range density fluctuations at pressures proximate to the critical pressure. By contrast, these signatures were absent in glasses of two model systems that lack a critical point. We also characterized the departure from equilibrium upon vitrification via the non-equilibrium index; water-like systems exhibited a strong pressure dependence in this metric, whereas simple liquids did not. These results reflect a surprising relationship between the metastable equilibrium phenomenon of liquid-liquid criticality and the non-equilibrium structure of glassy water, with implications for our understanding of water phase behavior and glass physics. Our calculations suggest a possible experimental route to probing the existence of the liquid-liquid transition in water and other fluids.

scholarly journals Active binary switching of soft colloids: stability and structural properties

Soft Matter ◽  
2021 ◽  
Author(s):  
Michael Bley ◽  
Joachim Dzubiella ◽  
Arturo Moncho Jorda
Keyword(s):  
Density Functional Theory ◽  
Phase Behavior ◽  
Structural Properties ◽  
Brownian Dynamics ◽  
Density Functional ◽  
Equilibrium Structure ◽  
Functional Theory ◽  
Binary Switching ◽  
Soft Colloids ◽  
Non Equilibrium

We employ reactive dynamical density functional theory (R-DDFT) and reactive Brownian dynamics (R-BD) simulations to study the non-equilibrium structure and phase behavior of an active dispersion of soft Gaussian colloids...

scholarly journals Parasitic Behavior in Competing Chemically Fueled Reaction Cycles

2021 ◽  
Author(s):  
Patrick S. Schwarz ◽  
Sudarshana Laha ◽  
Jacqueline Janssen ◽  
Tabea Huss ◽  
Job Boekhoven ◽  
...  
Keyword(s):  
Dynamic Behavior ◽  
Model Systems ◽  
Reaction Networks ◽  
Reaction Cycles ◽  
Non Equilibrium

Non-equilibrium, fuel-driven reaction cycles serve as model systems of the intricate reaction networks of life. Rich and dynamic behavior is observed when reaction cycles regulate assembly processes, such as phase...

scholarly journals Effects of Polydispersity on the Phase Behavior of Additive Hard Spheres in Solution

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1543
Author(s):  
Luka Sturtewagen ◽  
Erik van der Linden
Keyword(s):  
Phase Behavior ◽  
Critical Point ◽  
Volume Fraction ◽  
Hard Spheres ◽  
Second Virial Coefficient ◽  
Two Phase ◽  
Different Types ◽  
Asymmetric Partitioning ◽  
Average Size ◽  
Liquid Liquid Phase Separation

The ability to separate enzymes, nucleic acids, cells, and viruses is an important asset in life sciences. This can be realised by using their spontaneous asymmetric partitioning over two macromolecular aqueous phases in equilibrium with one another. Such phases can already form while mixing two different types of macromolecules in water. We investigate the effect of polydispersity of the macromolecules on the two-phase formation. We study theoretically the phase behavior of a model polydisperse system: an asymmetric binary mixture of hard spheres, of which the smaller component is monodisperse and the larger component is polydisperse. The interactions are modelled in terms of the second virial coefficient and are assumed to be additive hard sphere interactions. The polydisperse component is subdivided into sub-components and has an average size ten times the size of the monodisperse component. We calculate the theoretical liquid–liquid phase separation boundary (the binodal), the critical point, and the spinodal. We vary the distribution of the polydisperse component in terms of skewness, modality, polydispersity, and number of sub-components. We compare the phase behavior of the polydisperse mixtures with their concomittant monodisperse mixtures. We find that the largest species in the larger (polydisperse) component causes the largest shift in the position of the phase boundary, critical point, and spinodal compared to the binary monodisperse binary mixtures. The polydisperse component also shows fractionation. The smaller species of the polydisperse component favor the phase enriched in the smaller component. This phase also has a higher-volume fraction compared to the monodisperse mixture.

scholarly journals Studying thermodynamics of metastable states

2005 ◽  
Vol 3 (2) ◽  
pp. 115-128
Author(s):  
Yuri Kornyushin
Keyword(s):  
Heat Capacity ◽  
Relaxation Time ◽  
Metastable Phase ◽  
Nonequilibrium State ◽  
Metastable States ◽  
Metastable Equilibrium ◽  
General Description ◽  
Stable States ◽  
Heated Sample ◽  
Temperature Oscillations

Simple classical thermodynamic approach to the general description of metastable states is presented. It makes it possible to calculate the explicit dependence of the Gibbs free energy on temperature, to calculate the heat capacity, the thermodynamic barrier, dividing metastable and more stable states, and the thermal expansion coefficient. Thermodynamic stability under mechanical loading is considered. The influence of the heating (cooling) rate on the measured dynamic heat capacity is investigated. A phase shift of the temperature oscillations of an ac heated sample is shown to be determined by the relaxation time of the relaxation of the metastable nonequilibrium state back to the metastable equilibrium one. This dependence allows one to calculate the relaxation time. A general description of the metastable phase equilibrium is proposed. Metastable states in AB3 alloys are considered. Reasons for the change from the diffusional mechanism of the supercritical nucleus growth to the martensitic one as the heating rate increases are discussed. The Ostwald stage rule is derived.

scholarly journals Thermodynamic Analysis of Relaxation Model for Non-Equilibrium Phase Behavior of Hydrocarbon Mixtures

2021 ◽  
Vol 2090 (1) ◽  
pp. 012138
Author(s):  
I M Indrupskiy ◽  
P A Chageeva
Keyword(s):  
Relaxation Time ◽  
Phase Behavior ◽  
Relaxation Process ◽  
Thermodynamic Analysis ◽  
Balance Equation ◽  
Equilibrium Phase ◽  
Characteristic Relaxation Time ◽  
Relaxation Model ◽  
Entropy Balance ◽  
Non Equilibrium

Abstract Mathematical models of phase behavior are widely used to describe multiphase oil and gas-condensate systems during hydrocarbon recovery from natural petroleum reservoirs. Previously a non-equilibrium phase behavior model was proposed as an extension over generally adopted equilibrium models. It is based on relaxation of component chemical potentials difference between phases and provides accurate calculations in some typical situations when non-instantaneous changing of phase fractions and compositions in response to variations of pressure or total composition is to be considered. In this paper we present a thermodynamic analysis of the relaxation model. General equations of non-equilibrium thermodynamics for multiphase flows in porous media are considered, and reduced entropy balance equation for the relaxation process is obtained. Isotropic relaxation process is simulated for a real multicomponent hydrocarbon system with different values of characteristic relaxation time using the non-equilibrium model implemented in the PVT Designer module of the RFD tNavigator simulation software. The results are processed with a special algorithm implemented in Matlab to calculate graphs of the total entropy time derivative and its constituents in the entropy balance equation. It is shown that the constituents have different signs, and the greatest influence on the entropy is associated with the interphase flow of the major component of the mixture and the change of the total system volume in the isotropic process. The characteristic relaxation time affects the rate at which the entropy is approaching its maximum value.

THEORETICAL STUDIES OF TRANSIENT RAMAN SCATTERING OF NON-EQUILIBRIUM CARRIERS IN SEMICONDUCTORS — EFFECTS OF CARRIER COLLISIONS

1993 ◽  
Vol 07 (06) ◽  
pp. 331-353 ◽  
Author(s):  
C. CHIA ◽  
OTTO F. SANKEY ◽  
K. T. TSEN
Keyword(s):  
Raman Scattering ◽  
Optical Transition ◽  
Density Fluctuations ◽  
Collision Time ◽  
Time Resolved ◽  
Comprehensive Theory ◽  
Scattering Spectrum ◽  
Bandgap Semiconductors ◽  
Ultrashort Laser ◽  
Non Equilibrium

We present a comprehensive theory for time-resolved Raman scattering from non-equilibrium electrons in direct bandgap semiconductors. Specifically, we include (1) the effects of probing with ultrashort laser pulse: (2) the effects of finite carrier collision time; (3) the effects of band structure; and (4) the effects of damping in the optical transition, in the calculations of Raman scattering cross section. Both elastic and inelastic scattering processes are taken into account in formulating the effects of carrier collision time. The effects of damping in the optical transitions have to be considered for the experimental condition of probing with above-bandgap laser excitations even if under some circumstances they do not drastically change the lineshape of the single-particle-scattering spectrum due to spin-density fluctuations.

Assessment of Non-Equilibrium Phase Behavior Model Parameters for Oil and Gas-Condensate Systems by Laboratory and Field Studies (Russian)

2020 ◽  
Author(s):  
Ilya Mikhailovich Indrupskiy ◽  
Mikhail Yurievich Danko ◽  
Timur Nikolaevich Tsagan-Mandzhiev ◽  
Ayguzel Ilshatovna Aglyamova
Keyword(s):  
Phase Behavior ◽  
Oil And Gas ◽  
Equilibrium Phase ◽  
Field Studies ◽  
Gas Condensate ◽  
Model Parameters ◽  
Behavior Model ◽  
Non Equilibrium

scholarly journals Microtrabecular lattice of the cytoplasmic ground substance. Artifact or reality.

1979 ◽  
Vol 82 (1) ◽  
pp. 114-139 ◽  
Author(s):  
J J Wolosewick ◽  
K R Porter
Keyword(s):  
Critical Point ◽  
Osmium Tetroxide ◽  
Prolonged Exposure ◽  
Cultured Cells ◽  
Lattice Structure ◽  
Model Systems ◽  
Ground Substance ◽  
Specimen Preparation ◽  
Critical Point Drying ◽  
Cytoplasmic Ground Substance

The cytoplasmic ground substance of cultured cells prepared for high voltage transmission electron microscopy (glutaraldehyde/osmium fixed, alcohol or acetone dehydrated, critical-point dried) consists of slender (3-6 nm Diam) strands--the microtrabeculae (55)--that form an irregular three-dimensional lattice (the microtrabecular lattice). The microtrabeculae interconnect the membranous and nonmembranous organelles and are confluent with the cortices of the cytoplast. The lattice is found in all portions of the cytoplast of all cultured cells examined. The possibility that the lattice structure is an artifact of specimen preparation has been tested by (a) subjecting whole cultured cells (WI-38, NRK, chick embryo fibroblasts) to various chemical (aldehydes, osmium tetroxide) and nonchemical (freezing) fixation schedules, (b) examination of model systems (erythrocytes, protein solutions), (c) substantiating the relaibility of critical-point drying, and (d) comparing images of whole cells with conventionally prepared (plastic-embedded) cells. The lattice structure is preserved by chemical and nonchemical fixation, though alterations in ultrastructure can occur especially after prolonged exposure to osmium tetroxide. The critical-point method for drying specimens appears to be reliable as is the freeze-drying method. The discrepancies between images of plastic-embedded and sectioned cells, and images of whole, critical-point dried cells appear to be related, in part, to the electron-scattering properties of the embedding resin. The described observations indicate that the microtrabecular lattice seen in electron micrographs closely represents the nonrandom structure of the cytoplasmic ground substance of living cultured cells.

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