Range Of State Parameters Research Articles

Genuine Einstein–Podolsky–Rosen steering of generalized three-qubit states via unsharp measurements

We aim to explore all possible scenarios of (1 → 2) (where one wing is untrusted and the others two wings are trusted) and (2 → 1) (where two wings are untrusted, and one wing is trusted) genuine tripartite Einstein–Podolsky–Rosen (EPR) steering. The generalized Greenberger–Horne–Zeilinger (GHZ) state is shared between three spatially separated parties, Alice, Bob and Charlie. In both (1 → 2) and (2 → 1), we discuss the untrusted party and trusted party performing a sequence of unsharp measurements, respectively. For each scenario, we deduce an upper bound on the number of sequential observers who can demonstrate genuine EPR steering through the quantum violation of tripartite steering inequality. The results show that the maximum number of observers for the generalized GHZ states can be the same with that of the maximally GHZ state in a certain range of state parameters. Moreover, both the sharpness parameters range and the state parameters range in the scenario of (1 → 2) steering are larger than those in the scenario of (2 → 1) steering.

Fundamental equation of state developed on basis of Migdal’s phenomenological theory of critical point

In this work a fundamental equation of state (FEoS) with account taken of requirements of the scale theory of the critical point has been developed. The behavior of the FEOS in the asymptotic vicinity of the critical point is determined by the characteristics of the scaling function a(x) of the Helmholtz scale free energy F. The structure of the function a(x) is calculated on the basis of Migdal’s phenomenological theory and the hypothesis about the identical behavior of the isothermal compressibility coefficient at the critical and near-critical isohors near the critical point (Benedek’s hypothesis). The parameters of the singular component of the FEOS are calculated using the similarity theory. The proposed FEoS has been approved on the example of description of equilibrium properties of the refrigerating agent R1234yf in the range of state parameters: by a temperature from 220 K to 440 K and by pressure up to 40 MPa. The obtained results are discussed.

Study of the heat conductivity coefficient of heat carriers and working media in a wide range of state parameters

Study of the heat conductivity coefficient of heat carriers and working media in a wide range of state parameters

Extending thermal-hydraulic modelling capabilities of Apros into coiled geometries

In this work we extend modelling capabilities of the Apros two-fluid thermal hydraulic model into coiled geometries by re-defining the existing closure laws with new correlations valid in coiled tubes. The purpose is to be able to accurately model helically coiled steam generators, often adoped by small modular reactors (SMRs). For that, we identify suitable correlations and implement them into Apros. We also seek to identify areas which can already be accurately described with the existing models and, on the other hand, areas in which further experimental efforts are required for development of more accurate methods. Further, based on open literature, we compile a data base of experimental data for validation and verification purposes. We use the compiled data base for improving the accuracy of some of our calculation models. Specifically, we propose a modified version of an existing correlation for predicting the first dryout quality in helically coiled tubes. The proposed correlation is capable of estimating the first dryout quality with a reasonable accuracy in a range of state parameters and curvature ratios in which helically coiled steam generators generally operate.

The method for constructing the fundamental equation of state for SF6

The paper investigates issues related to construction of the equation of state which takes into account the peculiarities of substance behavior in the critical region and which is associated with the scalihg theory of critical phenomena. Construction method of a unified fundamental equation of state (UFEoS) for SFß that satisfies the power laws of scaling theory (ST) and the requirements imposed on the fundamental equations of state of the virial form (FEoS) is considered. UFEoS is based on a new representation of the scaling hypothesis in variables density – temperature and Benedek hypothesis. The authors have developed FEoS for SF6 in the range of state parameters: in density up to 2000 kg/m3, in temperature from 223.555 to 650 K. The authors have performed comparison with the certain fundamental equations of state for SF6: Scalabrin et al (2007 J. Phys. Chem. Ref. Data 36 617), Guder et al (2009 J. Phys. Chem. Ref. Data 38 33); Bezverkhii (2017 High Temp. 55 702). It is shown that in accordance with the requirements of ST, in contrast to the certain FEoS, the proposed equation of state transmits SF6 behavior into the vicinity of the critical point and in this region of state parameters significantly exceeds them in accuracy.

Экспериментальное исследование процесса извлечения органического вещества из твердых горючих ископаемых в широком диапазоне параметров состояния, включая и критическую область

The experimental study of supercritical extraction of the organic substance (OS) from various genetic types of oil shale in a wide range of state parameters was carried out. The dependences of the liquid yield on the temperature at pressure values varying from 3 to 20 MPa were identified. It was found that pressure has a significant effect on the overall degree of organic substance conversion and the liquid yield. With an increase in reactor pressure, the dissolving capacity and the solvent penetration depth increase which contributes to full extraction of soluble components of the organic substance from the porous structure. The results of the study of extraction of the organic substance from oil shale showed that with an increase in pressure the degree of organic substance conversion and the total liquid yield increase by 49-73% and 1,9-3,9 times respectively. The article concludes that variation in thermodynamic parameters of the supercritical fluid extraction process can be used to increase the degree of OS conversion and the liquid yield.

The cluster model of a hot dense vapor.

We explore thermodynamic properties of a vapor in the range of state parameters where the contribution to thermodynamic functions from bound states of atoms (clusters) dominates over the interaction between the components of the vapor in free states. The clusters are assumed to be light and sufficiently "hot" for the number of bonds to be minimized. We use the technique of calculation of the cluster partition function for the cluster with a minimum number of interatomic bonds to calculate the caloric properties (heat capacity and velocity of sound) for an ideal mixture of the lightest clusters. The problem proves to be exactly solvable and resulting formulas are functions solely of the equilibrium constant of the dimer formation. These formulas ensure a satisfactory correlation with the reference data for the vapors of cesium, mercury, and argon up to moderate densities in both the sub- and supercritical regions. For cesium, we extend the model to the densities close to the critical one by inclusion of the clusters of arbitrary size. Knowledge of the cluster composition of the cesium vapor makes it possible to treat nonequilibrium phenomena such as nucleation of the supersaturated vapor, for which the effect of the cluster structural transition is likely to be significant.

AQUA AMMONIA ELECTROLYTIC CHARACTER AND TPP COOLANT CONDUCTOMETRIC QUALITY CONTROL UNDER HIGH TEMPERATURES AND PRESSURES

To improve the operational conductometric steam quality control at the TPP, CHPP, and NPP, the technique for NaCl and NH4OH concentration in the saturated and superheated steam of the high- and supercritical pressure steam generators is developed, and a device for its implementation is offered. The error of determination in the range of the concentrations specific for the operated power plants is estimated. The equations describing the behavior of the thermodynamic dissociation constant, and limiting equivalent conductance of NH4OH in a wide range of state parameters that can be used in calculating the concentrations according to the proposed technique, as well as in water chemistry organization and management, are proposed. The assessment of the approximation error of dependences for the experimental data on the dissociation constants and limiting equivalent conductance is given.

Isochoric heat capacity and the T-ρ dependence of refrigerants of a propane series

An analysis of the principles of thermodynamic properties of refrigerants of a propane series is per- formed over a wide range of state parameters, including the critical range.

Simulation of the supramolecular organization and permittivity of methanol over a wide range of state parameters, including the supercritical region

Supramolecular structure models were suggested to describe the permittivity of methanol over a wide range of state parameters from the melting point to the supercritical region. The models were based on the quasi-chemical model of a nonideal associated solution. The permittivity and dipole correlation factor of methanol were calculated over the temperature range 177–593 K at pressures from 0.1 to 20 MPa for two supramolecular structure models. Methanol molecules formed chain associates according to the first model and chain and cyclic aggregates according to the second one. Both models successfully described the experimental data on pure methanol, but the inclusion of cyclic aggregates was necessary for consistency with models of methanol solutions in various solvents over the entire composition range. The thermodynamic and structural parameters of supramolecular aggregates were calculated. The particle-size distributions of aggregates and other integral and differential characteristics of association over the whole range of fluid methanol state parameters were determined for the first time.

Enthalpy of n-alkanes C7–C11 over a wide range of state parameters on the boundary curve and in the vicinity of the critical point

From experimental data on the specific heat at constant pressure for n-alkanes C7–C11, which were previously determined with a continuous-flow calorimeter, the enthalpies of these substances are calculated in the temperature range 300–620 K and the pressure range 0.5–60 MPa in the liquid and vapor phases. Extrapolation of the enthalpy isobars to the liquid-vapor boundary curve yields the enthalpies in the liquid and gas states and also gives the heats of evaporation. Generalized equations for the enthalpy of n-alkanes C5–C11 in the temperature range from the triple point to the critical point are presented. The calculation error is random; therefore, the approach proposed can be reliably enough extended to the entire homologous series.

On prediction of the thermal conductivity of liquids

Based on the Predvoditelev-Vargaftik formula, which relates uniquely thermal conductivity with density, a method is developed to predict the thermal conductivity of organic liquids, their mixtures, as well as petroleum products over a wide range of state parameters. The method employs a three-constant equation of state of a cellular model. The method is distinguished by the small amount of initial information required and an acceptable prediction accuracy.

Pulsational characteristics of the natural-circulation loop of a large-scale model of a light-boling boiling-water reactor

The results of an experimental study of a natural-circulation (NC) loop, whose geometrical and hydraulic characteristics are presented are described. The range of state parameters encompassed in the experiments is also indicated. The authors used a large-scale model of a low-boiling-water reactor, with natural heights and reduced stages of separate elements of the NC loop. The study confirmed that under the conditions the pulsations in the flow rate of the coolant occurs only in the transitional zone from natural circulation of the singlephase medium to natural circulation of the two-phase coolant.

Speed of ultrasound in water over a wide range of pressure and temperature

Experimental data are used to derive a formula for determination of the speed of sound in water over a wide range of state parameters.

An experimental study of thermal conductivity of aromatic hydrocarbons at high temperatures and pressures

Results are presented of an experimental study of thermal conductivity of aromatic hydrocarbons over a wide range of state parameters. Calculated equations which describe the experimental results well are obtained.

Generalization of experimental results on the thermal conductivity of Freons 21, 22, and 23

A system of computational equations is developed and handbook tables for the thermal conductivity of Freons 21, 22 and 23 are compiled in a broad range of state parameters.