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The bistability of spin‐transition materials is the origin of their multifunctional properties. It causes hysteresis phenomena, i. e., relaxation from a metastable state, of the spin (electronic) state, magnetization, etc. The collapse of a strong metastable state is a long‐time relaxation phenomenon. To study such nonequilibrium dynamical phenomenon, time evolution dynamics analyses are important. However, it is difficult to estimate long‐time relaxation phenomena by studying time evolution dynamics simulations due to the limitation of the simulation time. Furthermore, because the relaxation occurs in a stochastic process, a wide distribution of the relaxation time has to be considered in the analysis of the relaxation. To overcome these difficulties, we recently developed two methods for the quantitative estimation of the relaxation time from a metastable magnetic state and of the coercive field. In the first method, the relaxation time and coercive field are estimated using the survival (unrelaxed) probability of the ensemble of systems at each field, which extends the limitation of the simulation time. In the second method, they are estimated from the field‐dependent free energy barrier obtained from the survival probability under a sweeping field. These methods are applicable to the estimation of the relaxation time and coercive field of any magnetic particles. In this paper, staring with the Stoner–Wohlfarth model, the difference in the characteristic features of the magnetization reversal dynamics between zero and finite temperatures is discussed. Then, the methods of quantitative estimation of the coercive field and relaxation time are presented. The estimation of them using a neodymium permanent magnet grain was demonstrated with the two methods, and the methodological features and the validity of the estimation were discussed. The present study has a common theme to general metastable states including spin transitions. [ABSTRACT FROM AUTHOR]

Glass is a metastable state with a complex system involved many-body state interactions, which is the most challenging question of fundamental science. Coordination polymer glasses are a newcomer to the materials world, having many advantages over traditional glasses such as flexible coordination bonds, permanent pores and tailorable structures and properties. Herein, the background, preparation, glass forming mechanism, property and function of coordination-polymer glasses are reviewed, with the hope to well understand the structure, property and formation mechanism of glasses. It will provide theory for the development of new type of porous glasses. In addition, the development of the design, synthesis and processing of such glassy materials should be of great significant for energy environment, biological medicine and catalysis with practice applications in future. [ABSTRACT FROM AUTHOR]

A new equation of state for argon was developed with the view of extending the range of validity of the equation of state previously proposed by Tegeler et al. and obtaining a better physical description of the experimental thermodynamic data for the whole fluid region (single-phase, metastable, and saturation states). As proposed by Tegeler et al., this equation is also based on a functional form of the residual part of the reduced Helmholtz free energy. However, in this work, the fundamental equation for Helmholtz free energy was derived from the measured quantities CV(ρ, T) and P(ρ, T). The empirical description of the isochoric heat capacity CV(ρ, T) was based on an original empirical description explicitly containing the metastable states. The thermodynamic properties (internal energy, entropy, and free energy) were then obtained by combining the integration of CV(ρ, T). The arbitrary functions introduced by the integration process were deduced from a comparison between calculated and experimental pressure P(ρ, T) data. The new formulation is valid for the whole fluid region from the melting line to 2300 K and for pressures up to 50 GPa. It also predicts the existence of a maximum of the isochoric heat capacity CV along isochors, as experimentally observed in several other fluids. For many applications, an approximate form of the equation of state for the liquid phase may be sufficient. A Tait–Tammann equation is therefore proposed between the triple-point temperature and 148 K. [ABSTRACT FROM AUTHOR]

Resonance energies and quantum defects are reported for several Rydberg series for K2+ and Br3+. For K III ions, the [3s23p4 (1D2)]nd (2P,2D) and [3s3p5 (3P°2,0,1)]np, [3s23p4 (1S0)]nd (2D5/2,3/2) Rydberg series originating from the 3s23p5 (2P°1/2) metastable and 3s23p5 (2P°3/2) ground states are considered. For Br IV ions, the study is focused on the 4s24p (1D2, 3P2, 3P1)nd series originating from the 4s24p2 (1D2,3P2,3P1) states along with the 4s4p2 (3P1)np and 4s4p2 (1D2)np states originating from the 4s24p2 (3P1, 1D2) states. Calculations are performed in the framework of the modified atomic orbital theory (MAOT). Precise data are tabulated up to high excited stated n = 40. The results presented in this paper are in excellent agreement with the synchrotron radiation measurements of Alna'Washi et al. (Phys Rev A 90:023417, 2014) on K2+ and of Macaluso et al. (J Phys B At Mol Opt Phys 52:145002, 2019) on Br3+. These excellent agreements between theory and experiments indicate that the MAOT formalism can be used to report accurate high-lying excited Rydberg series of atomic species for the diagnostic and the modeling of astrophysical or laboratory plasmas. [ABSTRACT FROM AUTHOR]

The atomization of metastable superheated water injected into the atmosphere through a convergent-divergent nozzle at a temperature of 240–260°C was studied experimentally. The dispersion structure of the atomization plume is bimodal with a predominance of submicron droplets, whose proportion increases with increasing temperature and reaches 80% at the nozzle outlet at a water temperature of 260°C. The influence of droplet coagulation on the distribution of the proportion of large droplets along the length of the atomization plume was estimated. [ABSTRACT FROM AUTHOR]

The possibility of partial substitution of Si for Ge in the structure of Bi2GeO5 during synthesis from the melt and the effect of the substitution on the structure of the synthesized material have been studied. The microstructure of the synthesized compounds after their complete decomposition has been investigated. Using the phase powder X-ray diffraction- and optical microscopy methods, it has been found that metastable phases of bismuth silicate and germanate with structures of the Aurivillius type form a continuous series of solid solutions. It is shown that a mixed structure composed of large Bi4Si(Ge)3O12 crystals and the Bi12Si(Ge)O20 + Bi4Si(Ge)3O12 point eutectic is obtained after the decomposition of compounds of the Bi2SiO5–Bi2GeO5 quasi-binary system, regardless of the percentage of substitution of Si for Ge. Upon slow heating up to annealing temperatures (at a rate of 13.5°C/min), a structure of decomposition that is more finely dispersed and uniform than the structure obtained upon rapid heating (when charg the material into an already preheated furnace), which is more coarsely grained and inhomogeneous. Moreover, regions with a large structure similar to a dendritic one can appear in the material when the contents of silicon and germanium oxides in the alloy are close to each other (20/30–30/20 mol %). Such regions differ slightly in chemical composition from the surrounding material and appear during both slow and rapid heating of the material to annealing temperatures. [ABSTRACT FROM AUTHOR]

Establishing accurate as well as interpretable models of network activity is an open challenge in systems neuroscience. Here, we infer an energy-based model of the anterior rhombencephalic turning region (ARTR), a circuit that controls zebrafish swimming statistics, using functional recordings of the spontaneous activity of hundreds of neurons. Although our model is trained to reproduce the low-order statistics of the network activity at short time scales, its simulated dynamics quantitatively captures the slowly alternating activity of the ARTR. It further reproduces the modulation of this persistent dynamics by the water temperature and visual stimulation. Mathematical analysis of the model unveils a low-dimensional landscape-based representation of the ARTR activity, where the slow network dynamics reflects Arrhenius-like barriers crossings between metastable states. Our work thus shows how data-driven models built from large neural populations recordings can be reduced to low-dimensional functional models in order to reveal the fundamental mechanisms controlling the collective neuronal dynamics.

An extensive study of photoionization from neon excited states was performed. The R-matrix approach was applied to calculate a photoionization cross-section from the metastable 2 p 5 (2 P J f) 3 s [ K ] 0 , 2 and dipole-allowed 2 p 5 (2 P J f) 3 s [ K ] 1 states. The resonance structures and Cooper minimum accessible in photoionization from the excited states by the photons with energy below 30 eV were analyzed. The parameters of the lowest autoionizing states (AISs) of even parity were extracted by fitting of the photoionization cross-section. For the dipole-allowed states, calculations are presented for unpolarized, linearly and circularly polarized radiation. [ABSTRACT FROM AUTHOR]

If a mean-field spin ring interact with a cold external thermal reservoir, the system might first evolve to the paramagnetic metastable state along the paramagnetic path, and then fluctuate around the metastable state for a long period due to an energy barrier. The spin system must absorb sufficient energy from the thermal reservoir to achieve a phase transition to the final ferromagnetic equilibrium state. However, if an external magnetic field is applied to the system, the energy barrier becomes smaller, which can reduce the relaxation time of the system significantly. Moreover, if the magnetic intensity is strong enough, the energy barrier vanishes and the system evolves directly to the equilibrium state. [ABSTRACT FROM AUTHOR]

Emission and visible photoluminescence excitation spectra of Y2O2S:Er (1 at %) ceramics have been studied under different optical pumping conditions. The results demonstrate that visible anti-Stokes luminescence of the erbium-doped material has higher intensity in the case of pumping of the 4I13/2 metastable state of the dopant. Resonance IR photon wavelengths have been determined for two-photon excitation of visible emission in Y2O2S:Er. A method has been developed for the optical excitation of metastable states (excited-state excitation (ESE)) in anti-Stokes luminescence, which allows the nature of the corresponding electronic transitions in emission centers to be identified. [ABSTRACT FROM AUTHOR]

The review presents the results of molecular dynamics simulation of metastable states in the systems of the Lennard–Jones particles. The boundaries of the existence of metastable phases of liquid, gas, and crystal and their coexistence on a flat separating surface have been discussed. The data on the kinetics of fluctuation formation of a new phase in a superheated and supercooled liquid as well as in a superheated crystal have been analyzed within the framework of the classical nucleation theory. Peculiarities in the behavior of stability of the metastable phases have been established. The material is largely based on the works of the author and his colleagues. [ABSTRACT FROM AUTHOR]

Orientational structures of polymer-dispersed cholesteric liquid crystal under homeotropic anchoring and their transformations under the action of an electric field are studied. The switching of cholesteric droplets between different topological states are experimentally and theoretically demonstrated. Structures with λ + 1 / 2 -disclination are found and considered. These structures are formed during the transformation of a twisted toroidal configuration induced by a decrease in the electric field when a relative chiral parameter N 0 > 6.3 . The transformation of the initial structure with a bipolar distribution of the helix axis into a twisted toroidal configuration and then into a structure with λ + 1 / 2 -disclination is investigated in detail. The behavior of these structures under the influence of an external electric field, as well as the appearance of structures with λ − 1 / 2 -disclination, are studied. Obtained results are promising for the development of optical materials with programmable properties. [ABSTRACT FROM AUTHOR]

The time evolution of the thermally activated decay rates is considered. This evolution is of particular importance for the recent nanoscale experiments discussed in the literature, where the potential barrier is relatively low (or the temperature is relatively high). The single-molecule pulling is one example of such experiments. The decay process is modeled in the present work through computer solving the stochastic (Langevin) equations. Altogether about a hundred of high precision rates have been obtained and analyzed. The rates are registered at the absorption point located far beyond the barrier to exclude the influence of the backscattering on the value of the quasistationary decay rate. The transient time, i.e., the time lapse during which the rate attains half of its quasistationary value, has been extracted. The dependence of the transient times upon a damping parameter is compared with that of the inverse quasistationary decay rate. Two analytical formulae approximating the time-dependences of the numerical rates are proposed and analyzed. [ABSTRACT FROM AUTHOR]

Aerosol simulations especially for Earth System Models require a thermodynamics module with a good compromise between rigor and computational efficiency. We present and evaluate ISORROPIA-lite, an accelerated and simplified version of the widely used ISORROPIA-II v.2.3 aerosol thermodynamics model, expanded to include the effects of water uptake from organics and an updated interface communicating simulation diagnostics and information. ISORROPIA-lite assumes the aerosol is in metastable equilibrium (i.e., salts do not precipitate from supersaturated solutions) and treats the thermodynamics of Na+–NH4+–SO42––NO3––Cl––Ca2+–K+–Mg2+–Organics–H2O aerosol using binary activity coefficients from precalculated look-up tables. Off-line comparison between ISORROPIA-II and ISORROPIA-lite (without organic water effects) for more than 330,000 atmospherically-relevant states demonstrated that 'i') ISORROPIA-lite provides virtually identical results with ISORROPIA-II in metastable mode and 'ii') differences between stable mode ISORROPIA-II and ISORROPIA-lite are less than 25% for the concentrations of the various semivolatile aerosol components and similar to the differences between stable and metastable modes of ISORROPIA-II. Using ISORROPIA-lite reduced computational cost by 35% compared to ISORROPIA-II simulations in stable mode with online calculation of binary activity coefficients. Application of ISORROPIA-lite in the PMCAMx chemical transport model accelerated the 3D simulations by about 10% compared to using ISORROPIA-II in stable mode with changes in the concentrations of the major aerosol components of less than 10%. Simulations considering the effects of the organic aerosol water did not slow down ISORROPIA-lite but increased the concentrations of the inorganic semivolatile components especially at nighttime. Organic water could highly contribute to the total PM1 water mass and increase the concentrations of fine nitrate and ammonium by as much as 1 μg m–3 in places where the organic aerosol and RH levels are high.

The 134-residue phage L decoration protein (Dec) forms a capsid-stabilizing homotrimer that has an asymmetric tripod-like structure when bound to phage L capsids. The N-termini of the trimer subunits consist of spatially separated globular OB-fold domains that interact with the virions of phage L or the related phage P22. The C-termini of the trimer form a three-stranded intertwined spike structure that accounts for nearly all the interactions that stabilize the trimer. A Dec mutant with the spike residues 99-134 deleted (Dec 1-98 ) was used to demonstrate that the stable globular OB-fold domain folds independently of the C-terminal residues. However, Dec 1-98 was unable to bind phage P22 virions, indicating the C-terminal spike is essential for stable capsid interaction. The full-length Dec trimer is disassembled into monomers by acidification to pH <2. These monomers retain the folded globular OB-fold domain structure, but the spike is unfolded. Increasing the pH of the Dec monomer solution to pH 6 allowed for slow trimer formation in vitro over the course of days. The infectious cycle of phage L is only around an hour, however, implying Dec trimer assembly in vivo is templated by the phage capsid. The Thermodynamic Hypothesis holds that protein folding is determined by the amino acid sequence. Dec serves as an unusual example of an oligomeric folding step that is kinetically accelerated by a viral capsid template. The capsid templating mechanism could satisfy the flexibility needed for Dec to adapt to the unusual quasi-symmetric binding site on the mature phage L capsid., Competing Interests: CONFLICT OF INTEREST The authors declare no potential conflict of interest.

Aerosol simulations especially for Earth System Models require a thermodynamics module with a good compromise between rigor and computational efficiency. We present and evaluate ISORROPIA-lite, an accelerated and simplified version of the widely used ISORROPIA-II v.2.3 aerosol thermodynamics model, expanded to include the effects of water uptake from organics and an updated interface communicating simulation diagnostics and information. ISORROPIA-lite assumes the aerosol is in metastable equilibrium (i.e., salts do not precipitate from supersaturated solutions) and treats the thermodynamics of Na+-NH4 +-SO4 2--NO3 --Cl--Ca2+-K+-Mg2+-Organics-H2O aerosol using binary activity coefficients from precalculated look-up tables. Offline comparison between ISORROPIA-II and ISORROPIA-lite (without organic water effects) for more than 330,000 atmospherically-relevant states demonstrated that i) ISORROPIA-lite provides virtually identical results with ISORROPIA-II in metastable mode and ii) differences between stable mode ISORROPIA-II and ISORROPIA-lite are less than 25% for the concentrations of the various semivolatile aerosol components and similar to the differences between stable and metastable modes of ISORROPIA-II. Using ISORROPIA-lite reduced computational cost by 35% compared to ISORROPIAII simulations in stable mode with online calculation of binary activity coefficients. Application of ISORROPIA-lite in the PMCAMx chemical transport model accelerated the 3D simulations by about 10% compared to using ISORROPIA-II in stable mode with changes in the concentrations of the major aerosol components of less than 10%. Simulations considering the effects of the organic aerosol water did not slow down ISORROPIA-lite but increased the concentrations of the inorganic semivolatile components especially at nighttime. Organic water could highly contribute to the total PM1 water mass and increase the concentrations of fine nitrate and ammonium by as much as 1 µg m-3 in places where the organic aerosol and RH levels are high. [ABSTRACT FROM AUTHOR]

Safe transport of pressurized CO2 requires a profound knowledge of the processes' effect during the phase transition on catastrophic failure of a tanker filled with liquid CO2. This study presents experimental results and analyses associated with the characteristics of expansion waves during depressurization of liquified CO2 in a divergent cross-section vessel. It explores the rarefaction and evaporation waves velocities analyzed in different three vessel's regions based on the pressure records. Results showed that the evaporation wave velocity increased downward with decreasing cross-section and increased liquid volume fraction. Also, the upstream state properties after the isentropic expansion in the metastable region were determined. The results were compared with previously achieved outcomes of CO2 decompression from a constant cross-section rectangular duct.Comparisons indicated significant differences in the wave pattern. So, expansion waves velocities varying in different vessel regions while they were nearly constant for the duct. The evaporation wave velocities were nearly identical for the duct and the upper conical vessel's regions. But their divergence increased as the evaporation wave propagated downwards. Furthermore, the downstream two-phase flow in the conical vessel propagated in an increased cross-section toward the exit. In comparison, there was non-spontaneous two-phase propagation behind the evaporation wave due to the small exit cross-section in the rectangular duct. Additionally, during the isentropic expansion, the degree of superheat was higher for the conical vessel than the duct, resulting in significant discrepancies in the upstream flow properties.

Tungsten is the material of choice for the divertors in ITER, SPARC and future fusion reactors. Accurate diagnosis of tungsten erosion and migration is important for first wall life time, slag production and core performance. The addition of a magnetic presheath requires time-dependent collisional radiative effects to be included for accurate neutral tungsten collisional radiative modeling. Gross erosion measurements could be modified by a factor of 10 due to the inclusion of time-dependent effects for ITER relevant divertor conditions. A simple sputtering model and sheath density model are developed to investigate time-dependent collisional radiative effects. Neutral tungsten spectral lines populated from different metastable levels depend on model parameters leading to potential spectroscopic diagnostics of plasma parameters. Electron temperatures inferred from spectroscopic line ratios are in agreement with Langmuir probe measurements in the Compact Toroidal Hybrid.

Purpose. The purpose of this paper is to substantiate the technological solution of equilibrium conditions in the system “methane – water phase – hydrate – R-2M”; to reveal existing ecological problems of methane gas hydrate extraction from the Black Sea bottom; to determine whether gas hydrate deposits of Black Sea methane are an ecological problem or should be considered as an energy source, to explain the necessity of introduction of the effect of forced self-preservation of methane gas hydrates into development of gas hydrates from the sea bottom. Results. This article analyses current research on gas hydrates specifically in the Black Sea. It shows that the necessary conditions exist for the accumulation of gas hydrates in certain areas of the deep Black Sea (one of the most favourable regions among modern sea basins). This article discusses some ideas for the development of experimental studies of the metastable state of methane gas hydrates at negative temperatures: stability and mechanisms of decomposition. Despite the great variety of technological solutions and schemes of gas hydrates application proposed by the leading researchers in the world, they have been tested practically on a small number of laboratory and model installations, mainly for water desalination and concentration of water solutions, separation of two-component gas mixtures. In fact, there is no data to calculate the processes of formation and melting of ice-gas hydrate methane. The effect of self-preservation of methane gas hydrates deserves special attention. Scientific novelty. An attempt was made to substantiate the issue of whether gas hydrate deposits of methane in the Black Sea are an environmental problem or should they be considered as an additional source of energy and even as a “fuel of the future”. The authors for the first time introduced the concept of “forced preservation (activation) effect of methane gas hydrates”, which makes it possible to stabilize methane hydrate decomposition when the system is transferred from the area of hydrate stability to the area of thermodynamic parameters, thus significantly reducing the environmental problems of the Black Sea. Practical value. This article offers a technological solution for stabilization of equilibrium conditions by hydrophobic material “Ramsinks-2M” in the system “methane-water phase-hydrate-R-2M” to regulate the self-preservation effect of methane gas hydrates

Using experimental data from literature [1], hydrogen density-pressure (ρ-P) and density-temperature (ρ-T) phase diagrams were drawn and evaluated for various pressure and temperature intervals. Solid, liquid, vapor, gas, supercritical liquid, supercritical gas and supercritical fluid regions were identified on the obtained diagrams. There are exact equilibrium boundaries between subcritical phases. On the contrary, it is concluded that there are no such exact boundaries for supercritical phases. Formation of the supercritical fluid between liquid and gas phases explained thermodynamically with first and second order partial derivatives of chemical potential relative to pressure at constant temperature. • Literature values for hydrogen are used for the graphical examination of the supercritical phases on phase diagrams. • Liquid-vapor, superheated steam, overcritical fluid and supercritical fluid regions were determined on the phase diagram. • Supercritical region observed starting at approximately 8 bar pressure between 34-36 K isotherms. • Critical pressure of ionization or decomposition for H 2 molecules was found as 1800 bar. • Supercritical fluid formation explained thermodynamically and a novel p-T phase diagram for hydrogen provided. [ABSTRACT FROM AUTHOR]

In this paper, the stochastic stability of a vibro-impact system with multiple excitation forces is studied. Due to the multiple external excitations and the coexistence of metastable states, the solution of each attractor's activation energy, which is specifically used to characterize the attractor's stochastic stability, is much more suitable for the stability analysis rather than the solution of the probability density function. Based on the large deviation theory, the asymptotic analysis is carried out, and a time-varying Hamilton's equation for the quasi-potential of the vibro-impact system is derived. To verify the effectiveness of the theoretical analysis, two detailed examples, where an impact attractor and a non-impactor coexist in the system, are conducted. By the application of the action plot method, the activation energies and the most probable exit paths for each attractor are derived. Compared with the numerical simulation, the results show very good agreement. Moreover, it shows that the existence of transient chaos near the attractor could seriously deteriorate the attractor's stability. [ABSTRACT FROM AUTHOR]

A mathematical model of the evaporation of a polydisperse ensemble of drops, with allowance for a nonlinear 'diffusion' term in the kinetic equation for the population density distribution function, is developed. The model describes the interaction of a gas phase with vaporizing drops: it has great potential for application in condensed matter physics, thermophysics and engineering devices (e.g. spray drying, cooling, power engineering). The kinetics of heat transfer between phases is theoretically studied. An analytical solution to the integro-differential equations of the process of droplet evaporation is found in a parametric form. Analytical solutions in the presence and absence of the 'diffusion' term are compared. It is shown that the fluctuations in particle evaporation rates ('diffusion' term in the Fokker-Planck equation) play a decisive role in the evolutionary behaviour of a polydisperse ensemble of vaporizing liquid drops. [ABSTRACT FROM AUTHOR]

The experimental study of cooperative fast transport of non-wetting fluid in a disordered nanoporous medium is carried out in this work. New experimental data for simultaneous measurement of fluid flow, filled pore volume and pressure have been obtained. Dependencies of critical pressure and flow on porous particle mass and rapid compression energy have also been established. A new transport mechanism is proposed. The dynamics of fluid transport is represented as a process of evolution of two macroscopic growing modes of transport—spontaneous transport that occurs when new critical pressure of dynamic percolation transition and fluid transport caused by a constant critical pressure under impact compression of nanoporous particles suspension. Following the theory of critical dynamics of multiscale phenomena, a condition for the interaction of modes is proposed. Taking into account this interaction, rapid spontaneous transport is adjusted to the slow impact of impact compression, and the experimental dependencies should be described by the slow mode—impact compression. Such transport occurs simultaneously in two different time scales and is determined by the properties of spontaneous transport. The experimental dependencies are quantitatively described in the kinetic model. Under conditions of filled pores, the response of a fluid transport to impact is characterized by positive feedback. [ABSTRACT FROM AUTHOR]

Sorption–desorption hysteresis (SDH) may control distributions of chemicals across diverse environmental phases, including soils and sediments. Formation of metastable states caused by pore deformation or inelastic swelling of a sorbent and their persistence during desorption have been considered in the literature as one reason for "true" SDH. Such metastable states may lead to the lack of closure of the sorption–desorption loop at non‐zero sorbate concentrations, a phenomenon often noted in soil and environmental literature. SDH has often been characterized using single‐point desorption isotherms (DIs) that combine sorbed states reached during single desorption steps started from different points along a sorption isotherm (SI). This work aimed to demonstrate how single‐point DIs could be used to characterize SDH in the liquid phase in terms of the Gibbs free energy accumulated in some non‐relaxed sorbed states belonging to a DI, as compared with the states of the same composition (sorbed concentration) belonging to an SI. Based on the literature data on SIs and single‐point DIs of pesticides and some hydrocarbons on soils, artificial soils, minerals and sediments, these quantities of extra free energy were determined and their changes in the selected sorbate‐sorbent systems were examined. When the extent of SDH decreases with increasing solute concentration, these additional free energies decrease. They may remain constant or even increase, suggesting, in the latter case, that more work is needed to perturb a sorbent structure at higher sorbed concentrations. Magnitudes of calculated extra free energies may be helpful in examining whether irreversible pore deformation in a sorbent and formation of metastable states are the reasons for SDH. This paper proposes a novel approach for quantifying liquid‐phase SDH in cases in which a thermodynamic justification is sought. It advances the ability to predict the fate of chemicals in typical soil/sediment environments. Highlights: Desorption from soils and sediments to solutions may be hysteretic due to formed metastable statesHysteresis is quantified in terms of excessive free energies of metastable statesExtra free energies are sorbate‐ and sorbent‐dependent, varying across sorption isothermsSingle‐point desorption isotherms allow quantification of the free energy excess in metastable states [ABSTRACT FROM AUTHOR]

Ceramic is among the complicated materials to use in the design of fine objects. Complex shapes without any major defect are not easy to produce. In most of the cases, the production of ceramic parts is the results of three steps. Firstly, the “sculpture” of the raw piece by adding raw materials to lead to the final object. Secondly, the “drying” and finally the “high temperature oven-dry” of the dried raw object to transform the granular dough into a nice consistent compact material. Exploiting the special characteristics of ceramic is not only a thing of the past. Nowadays new possibilities, i.e., shapes and styles, can be offered in the use of ceramics, and especially where it concerns the application of the Additive Manufacturing (AM) concept. The combination of Computer Aided Design (CAD) to AM opens a completely new means of finding novel ways of processing final objects. By choosing to use kaolin clay without any chemical additions (or improvers) as “a model material,” the ability to produce controlled structures with freedom in design by additive deposition modeling is exposed. Discussions relate to the concomitant control of the process parameters, the kaolin hydration and the complexity of printed structures. The optimization of process parameters (nozzle speed, layer thickness, wall thickness) were defined with the calibration of the material flow. Both windows adjusting water content in dough (%wt) and imposing pressure in the tank of the 3D printer have been defined accordingly. The role of layer impression support was also found to be important. This study credits to use the state-of-the art technique (3D printing) to explore sustainable manufacturing of potteries.

The molecular dynamics method is used to study the process of development of dynamic instability of a thin film, leading to its destruction. The calculations are performed for a thin aluminum film using the interatomic interaction potential tested by comparing the numerical results with the analytical ones from the elasticity theory. An original approach which allows one to calculate the dispersion law of long‐wave phonons in ultrathin films is developed. The temperatures (<600 K) at which the system remains stable for 0.6 ns are found. This makes it possible to analyze the low‐frequency part of the spectrum down to the minimum frequency νmin = 0.0166 THz, and to determine the vibration frequency of the longest bending wave ν0 = 0.033 THz which decreases with increasing temperature, and therefore, its period grows. Once the vibration period becomes comparable with the time of simulation, there occurs a continuous increase in the amplitude of this mode which will be referred to as "retarded mode." It is shown that the film destruction begins with the attainment of a certain critical value of the bending wave amplitude. [ABSTRACT FROM AUTHOR]

High entropy alloys and metallic glasses, as two typical metastable nanomaterials, have attracted tremendous interest in energy conversion catalysis due to their high reactivity in nonequilibrium states. Herein, a novel nanomaterial, layered high entropy metallic glass (HEMG), in a higher energy state than low-entropy alloys and its crystalline counterpart due to both the disordered elemental and structural arrangements, is synthesized. Specifically, the MnNiZrRuCe HEMG exhibits highly enhanced photothermal catalytic activity and long-term stability. An unprecedented CO 2 methanation rate of 489 mmol g -1 h -1 at 330 °C is achieved, which is, to the authors' knowledge, the highest photothermal CO 2 methanation rate in flow reactors. The remarkable activity originates from the abundant free volume and high internal energy state of HEMG, which lead to the extraordinary heterolytic H 2 dissociation capacity. The high-entropy effect also ensures the excellent stability of HEMG for up to 450 h. This work not only provides a new perspective on the catalytic mechanism of HEMG, but also sheds light on the great catalytic potential in future carbon-negative industry., (© 2024 Wiley‐VCH GmbH.)

Measurements of emission cross sections for the O + − N 2 collision system with the incident beam of 1–10 keV O + in the ground O + (4 S) and metastable O + (2 D) and O + (2 P) states are reported. The emission cross section induced by incident ions in the metastable state O + (2 P) is much larger than that for the ground O + (4 S) state. The emission cross section of N 2 + ion for (0 , 0) , (0 , 1) , and (1 , 2) bands system is measured and the ratio of intensities for these bands is established as 1 0 : 3 : 1. It is shown that the cross sections for the N + ∗ ions emissions in the dissociative charge exchange processes increase with the increase of the incident ion energy. The energy dependence of the emission cross section of the band (0 , 0) λ = 3 9 1. 4  nm of the first-negative band system of the N 2 + and degree of linear polarization of emission in O + − N 2 collision are measured for the first time. An influence of an admixture of the ion metastable state on a degree of linear polarization is revealed. The mechanism of the processes realized during collisions of ground and metastable oxygen ions on molecular nitrogen have been established. It is demonstrated that for O + − N 2 collision system the degree of linear polarization by metastable O + (2 P) ions is less compared to those that are in the ground O + (4 S) state and the sign of emission of degree of linear polarization of excited molecular ions does not change. [ABSTRACT FROM AUTHOR]

Temperature and time dependences of the viscosity of InBi100 –хPbх melts (where х = 0, 19, 40, 60, 80, 100 at %) have been studied by the method of damped torsional oscillations. Intermediate compositions of this system have been studied for the first time. It has been demonstrated that the viscosity and the oscillation period curves for InBi–Pb melts containing up to 40 at % Pb measured in the heating and cooling modes are coincident and monotonic. In the InBi40Pb60 melt, the hysteresis of the viscosity and oscillation period of the suspension system with the melt is observed only in the first heating–cooling cycle, and in InBi20Pb80, after the first heating–cooling cycle, the viscosity hysteresis changes sign from negative to positive. From the results of measurements of the time dependences of the viscosity of the InBi40Pb60 melt at a constant temperature, the relaxation time is determined, which decreases exponentially with increasing temperature. The activation energy of the melt homogenization process was found to be Ea = 83 kJ/mol. The relaxation time and activation energy of the homogenization process determined in this work significantly exceed the values obtained in the literature for other systems. The long relaxation time near the liquidus suggests that this nonequilibrium state in the InBi40Pb60 melt is metastable. [ABSTRACT FROM AUTHOR]

The intriguing process of protein folding comprises discrete steps that stabilize the protein molecules in different conformations. The metastable state of protein is represented by specific conformational characteristics, which place the protein in a local free energy minimum state of the energy landscape. The native‐to‐metastable structural transitions are governed by transient or long‐lived thermodynamic and kinetic fluctuations of the intrinsic interactions of the protein molecules. Depiction of the structural and functional properties of metastable proteins is not only required to understand the complexity of folding patterns but also to comprehend the mechanisms of anomalous aggregation of different proteins. In this article, we review the properties of metastable proteins in context of their stability and capability of undergoing atypical aggregation in physiological conditions. [ABSTRACT FROM AUTHOR]

Background  Homeopathic potencies have been shown to interact with a range of solvatochromic dyes to produce spectroscopic changes in the visible region of the electromagnetic spectrum. Furthermore, the nature of the changes observed under different experimental conditions is beginning to limit the number of possible hypotheses that can be put forward regarding the fundamental identity of potencies. Aims and Methods  The present study uses β-cyclodextrins to encapsulate solvatochromic dyes of widely varying structures. The purpose of this approach is to de-couple the primary dye–potency interaction from any subsequent aggregation effects. Results  Despite large differences in molecular structure between dyes, results show that potencies affect all dyes according to the same fundamental principles. Specifically, positively and negatively solvatochromic dyes collectively respond in opposite and complementary ways to potencies in accordance with the differential stabilisation of their excited and ground electronic states. Under the conditions of encapsulation, positively solvatochromic dyes display a bathochromic shift of, on average, 0.4 nm with a 2% absorbance change, and negatively solvatochromic dyes display a hypsochromic shift of, on average, 0.2 nm with a 1% absorbance change. This behaviour is only ever seen in two situations—where solvent becomes more polar or where an electric field is applied to solutions of dyes. Conclusions  The conditions used in this and previous studies to investigate the interaction of potencies with solvatochromic dyes preclude increased polarity of solvent as being responsible for the observed effects and that an explanation in which potencies carry an electric field (or electric field-like) component is by far the more likely. From the magnitude of the spectral changes induced in the dye Brooker's merocyanine by Arsenicum 10M, an estimate of the strength of the postulated electric field of 1.16 × 10 7  V/m can be made, which is comparable with the potential difference across cell membranes. [ABSTRACT FROM AUTHOR]

[Display omitted] • The amount of dissociation of natural gas hydrates below the quadruple point is non-linearly correlated with the depressurization rate. • The existence of a metastable state could be beneficial for increasing the gas production rate of methane hydrates and for improving the recovery rate of reservoir temperatures. • When hydrates disengagement the metastable region, the gas production rate of hydrates is improved. • The time that the hydrate is in the metastable region needs to be kept at the right time interval. The depressurization method has been proven to be an energy-efficient and relatively feasible production technique for natural gas hydrates. However, during the depressurization process, especially when the hydrates reservoir approaches the quadruple point, it is inevitable to experience phenomena such as freezing and hydrates secondary formation. Therefore, most researchers think that the P-T near the quadruple point may not be suitable for the dissociation of hydrates and a series of depressurization control methods were adopted to avoid this. However, according to other researchers, the effect of depressurization near the quadruple point on the dissociation behavior of hydrates is not inhibitory, but even a promoting effect to a certain extent. In addition, A special region called metastable state appears with the decrease of pressure near the quadruple point, which makes the dissociation behavior of hydrate below the quadruple point different from that above it. Therefore, in this paper, to reveal more clearly the dissociation behavior of natural gas hydrates near the quadruple point and the influence of the existence of metastable state on the depressurization dissociation of hydrate, the dissociation experiment of natural gas hydrates in the porous medium peri -freezing point is investigated in different depressurization rates and amplitudes, peri -freezing point and pressure stabilization times quadruple point. Experimental studies have shown that the amount of dissociation of natural gas hydrates below the quadruple point is non-linearly correlated with the depressurization rate. This correlation is synergistically regulated by the depressurization magnitude per unit of time and the environmental heating efficiency. Compared with the dissociation of hydrates above the freezing point, the metastable region does not show an obvious inhibitory effect on the dissociation of hydrates, and it even effectively shortens the dissociation time of hydrates and improves the heat transfer efficiency of the reservoir. Under the dissociation pressure of 2.5 MPa (metastable state), the reservoir temperature rose from 0 °C to 1 °C in 2.9 h, 3.6 h less than that under 2.6 MPa (above the quadruple point), and 0.7 h more than that under 1.0 MPa (below the metastable state). In addition, the gas production rate of hydrates is improved when hydrates disengagement the metastable region, increasing by 65.12 % compared with those above the quadruple point. However, pressure stabilization times when hydrates are in a metastable state need to be kept within a certain interval, too long or short pressure stabilization time will inhibit the dissociation of hydrates, and reduce the promotion effect on the dissociation of hydrates. [ABSTRACT FROM AUTHOR]

Measurements of the transmission of neutrons through two samples of 235U and Cd, which are simultaneously on neutron beam, with different sequence of their location for different exposure times of the samples on the beam, are performed. Previously observed difference in these transmissions is confirmed – asymmetry of transmission. The purpose of the measurements is to determine the lifetime of the expected metastable states, to explain the observed asymmetry of transmission. Based on the results of asymmetry of transmission measurements, it was found that it is less than 5 s.

The intermetallic FeRh system has displayed tremendous fascination to investigators due to its remarkable physical properties and potential applications. Here we synthesized near-equiatomic FeRh films on MgO (001) substrate by magnetron co-sputtering of Fe and Rh, and our results revealed a magnetic glass (MG) state existing after field cooling to low temperature. The MG state is nonequilibrium with a configuration of metastable supercooled ferromagnetic (FM) and equilibrium antiferromagnetic (AFM) phases, and arises from a kinetic arrest of the first-order FM–AFM phase transition. Our finding is beneficial to a better understanding of the underlying mechanism of the FeRh phase transition.