Odessa State Academy of Refrigeration

Odessa, Ukraine

Odessa State Academy of Refrigeration

Odessa, Ukraine
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Yakub E.S.,Odessa I I Mechnikov National University | Yakub L.N.,Odessa State Academy of Refrigeration
Fluid Phase Equilibria | Year: 2013

New model equation of state (EOS) for highly compressed polymerizing fluid is developed and calibrated on ab initio simulation data. The EOS was applied to the prediction of the fluid-fluid transition in strongly compressed nitrogen. Location of the fluid-fluid phase transition line and position of the critical point on it were estimated and compared with earlier predictions and experimental shock compression data. © 2012 Elsevier B.V.

Petrenko V.O.,National Taiwan University | Petrenko V.O.,Odessa State Academy of Refrigeration | Volovyk O.S.,Odessa State Academy of Refrigeration
International Journal of Refrigeration | Year: 2011

This paper describes the construction and performance of a novel combined system intended for natural gas transportation and power production, and for cooling of gas transported in a gas-main pipeline. The proposed system includes a gas turbine compressor, a combined electrogenerating plant and an ejector refrigeration unit operating with a hydrocarbon refrigerant. The combined electrogenerating plant consists of a high-temperature steam-power cycle and a low-temperature hydrocarbon vapor power cycle, which together comprise a binary vapor system. The combined system is designed for the highest possible effectiveness of power generation and could find wide application in gas-transmission systems of gas-main pipelines. Application of the proposed system would enable year-round power generation and provide cooling of natural gas during periods of high ambient temperature operation. This paper presents the main results of a theoretical study and design performance specifications of a low-grade heat-driven pilot ejector refrigeration machine operating with butane and isobutane. © 2010 Elsevier Ltd and IIR. All rights reserved.

Gannitskiy I.,Odessa State Academy of Refrigeration
Modern Problems of Radio Engineering, Telecommunications and Computer Science - Proceedings of the 10th International Conference, TCSET'2010 | Year: 2010

This article describes a study the structure of calls on a modern telecommunication networks; such parameter as number of calls is described in detail.

Yakub L.N.,Odessa State Academy of Refrigeration
Low Temperature Physics | Year: 2013

We made an attempt to predict location of the melting line of polymeric nitrogen using two equations for Helmholtz free energy: proposed earlier for cubic gauche-structure and developed recently for liquid polymerized nitrogen. The P-T relation, orthobaric densities and latent heat of melting were determined using a standard double tangent construction. The estimated melting temperature decreases with increasing pressure, alike the temperature of molecular-nonmolecular transition in solid. We discuss the possibility of a triple point (solid-molecular fluid-polymeric fluid) at ~80 GPa and observed maximum of melting temperature of nitrogen. © 2013 AIP Publishing LLC.

Shvets V.T.,Odessa State Academy of Refrigeration
Journal of Experimental and Theoretical Physics | Year: 2013

The effective ion-ion interaction, free energy, pressure, and electric resistance of metallic liquid helium have been calculated in wide density and temperature ranges using perturbation theory in the electron-ion interaction potential. In the case of conduction electrons, the exchange interaction has been taken into account in the random-phase approximation and correlations have been taken into account in the local-field approximation. The solid-sphere model has been used for the nuclear subsystem. The diameter of these spheres is the only parameter of this theory. The diameter and density of the system at which the transition of helium from the singly ionized to doubly ionized state occurs have been estimated by analyzing the pair effective interaction between helium atoms. The case of doubly ionized helium atoms has been considered. Terms up to the third order of perturbation theory have been taken into account in the numerical calculations. The contribution of the third-order term is significant in all cases. The electric resistance and its temperature dependence for metallic helium are characteristic of simple divalent metals in the liquid state. The thermodynamic parameters - temperature and pressure densities-are within the ranges characteristic of the central regions of giant planets. This makes it possible to assume the existence of helium in the metallic state within the solar system. © 2013 Pleiades Publishing, Ltd.

Trotsenko A.V.,Odessa State Academy of Refrigeration
Russian Journal of Physical Chemistry A | Year: 2011

The finiteness and positive value of the slope of the saturation curve at the critical point according to its location in the region of a thermodynamic surface restricted by the curves of inversion and saturation are substantiated. It is shown that any two derivatives of the first order formed with respect to volume, internal energy, entropy, enthalpy, and the Helmholtz energy, one of which is taken at a fixed value of pressure and the other at a fixed value of temperature, are equal in the critical state. New sets of the critical conditions for a pure substance are obtained. © 2011 Pleiades Publishing, Ltd.

Rogankov V.B.,Odessa State Academy of Refrigeration | Levchenko V.I.,Odessa State Academy of Refrigeration
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2013

By combining a measurable vapor-liquid coexistence curve and the extended van der Waals-type of equation of state (EOS) with the additional temperature-dependent coefficient, the phenomenological model of global fluid asymmetry has been developed separately for both coexisting bulk phases in the entire range of subcritical states. It is shown, in particular, that the adequate description of a liquid branch and its near-critical vicinity in terms of appropriate critical exponents and amplitudes connected by the two-scale-factor universal interrelations can be achieved. The asymmetric influence of heterophase fluctuations on the criticality of gaseous states is demonstrated. It is inherently similar to the well-known Fisher's droplet model, which corresponds to the scaling EOS too. The principle of corresponding isotherms has been formulated without any adjustable parameters. An attempt to avoid the use of a locally singular coexistence-curve diameter is proposed in the framework of two alternative models. The accurate vapor-liquid data for two fluid metals, Rb and Cs, as well as two molecular fluids, C2H 6 and CO2, are reanalyzed by the above models to confirm the presumed opportunity. © 2013 American Physical Society.

Solomitsky M.,Odessa State Academy of Refrigeration
Modern Problems of Radio Engineering, Telecommunications and Computer Science - Proceedings of the 11th International Conference, TCSET'2012 | Year: 2012

Approaches to the formal description of interaction between the convergent telecommunication network and environment are offered. © 2012 Lviv Polytechnic Natl Univ.

Shvets V.T.,Odessa State Academy of Refrigeration
JETP Letters | Year: 2012

The effective proton-proton interaction in metallic hydrogen has been calculated for various densities. In the potential of this interaction, which can be represented in the form of a series of perturbation theory in the electron-proton interaction, the second- and third-order terms are taken into account. The second-order term gives a comparatively shallow potential well with one minimum. The position of the minimum corresponds to the equilibrium mutual position of protons in metallic hydrogen. When the third-order term is additionally taken into account, the potential has two characteristic minima; the position of one of them corresponds to the distance between the protons in a hydrogen molecule. The depths of these potential wells depend on the density of the system. At fairly high densities, only the potential well corresponding to the equilibrium position of protons in the metallic phase holds in the proton-proton potential. Owing to the presence of two minima in the effective proton-proton potential, the density of hydrogen at the point of transition to the metallic state can be estimated. Analysis of the effective proton-proton interaction makes it also possible to estimate the possibility of the existence of metallic hydrogen in a stable state at quite low temperatures. © 2012 Pleiades Publishing, Ltd.

Semenyuk V.,THERMION Company | Dekhtiaruk R.,Odessa State Academy of Refrigeration
Journal of Electronic Materials | Year: 2013

We present the results of an experimental study of a cooling system based on a novel thermoelectric module specifically designed for thermal management of high-power light-emitting diodes (LEDs). The Seoul Semiconductor LED W724C0 device was chosen for experimental validation of the efficiency of the proposed cooling unit. Two cooling systems with identical heat sinks were tested for comparison: a state-of-the-art one based on an insulated metal substrate-printed circuit board (IMS-PCB) and a system with thermoelectric cooling. The obtained results show that use of thermoelectrics results in a considerable reduction of the LED operating temperature, providing increased light output and greatly increased LED lifetime. © 2013 TMS.

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