О-42 1/f-Noisa under Conditions of Interaction between Phase Transitions [] / V. N. Skokov, A. V. Reshetnikov, V. P. Koverda, A. V. Vinogradov // High Temperature. - 2001. - Vol. 39, N 2. - С. 296-301: il. - Bibliogr.: p. 321 (13 n.) Рубрики: ФИЗИКА Кл.слова (ненормированные): 1/f-NOISE -- PHASE TRANSITIONS \\\\Expert2\\NBO\\High Temperature\\2001, v.39, p.316.pdf |
F 68 Flicker-Noise in Superheated Liquid Jets / A. V. Reshetnikov, V. P. Skripov, V. P. Koverda, N. A. Mazheiko, A. V. Vinogradov // Heat Transfer Research. - 2004. - Vol. 35, № 1-2. - С. 59-66 Рубрики: ФИЗИКА Кл.слова (ненормированные): BOILING-UP LIQUID -- CRITICAL MODES -- VAPOR FORMATION Аннотация: Change of the shape of a boiling-up liquid jet flowing from a high-pressure vessel at high superheatings was investigated experimentally. Mechanisms of volumetric heterogeneous and homogeneous nucleation are distinguished and their connection with critical modes of outflow is determined. Results of the experimental study of recoil of boiling-up liquid jets in a thermodynamically strong nonequilibrium mode of outflow are presented. The dynamics of vapor content fluctuations is studied by a method of photometry of passed laser radiation. Fluctuations of pressure in a superheated liquid jet at various mechanisms of vapor formation are measured by a method of strain metering. It was found that in intense volumetric boiling-up of a superheated liquid jet the power spectrum of fluctuations has a low-frequency component (flicker-noise) which diverges according to the 1/f law. This effect is related to nonequilibrium phase transitions in the system |
1/f noise and self-organized criticality in crisis regimes of heat and mass transfer / V. N. Skokov, V. P. Koverda, A. V. Reshetnikov, V. P. Skripov, N. A. Mazheiko, A. V. Vinogradov // International Journal of Heat and Mass Transfer. - 2003. - Vol. 46, № 10. - С. 1879-1883 Рубрики: ФИЗИКА Кл.слова (ненормированные): 1/f-NOISE -- FLUCTUATIONS -- FLICKER NOISE Аннотация: Thermal fluctuations under the transition from nucleate to film boiling of water on a wire heater and fluctuations of jet form during an outflow of superheated liquid from a pressure vessel were experimentally investigated. It has been found that power spectrum of the fluctuations has got a low frequency component corresponding to a 1/f law (flicker noise).??The effect given is connected with the occurrence of nonequilibrium phase transitions in the systems: a crisis of heat transfer under the transition from nucleate to film boiling and a crisis of a flow in boiling-up of superheated liquid jet?? |
F 17 Faizullin, M. Z. Glass transition and crystallization of low-temperature amorphous condensates of the water-propane mixture / M. Z. Faizullin, A. V. Vinogradov, V. P. Koverda // Doklady Physical Chemistry. - 2012. - Vol.442. - С. 16-18 Рубрики: ФИЗИКА Кл.слова (ненормированные): LOW TEMPERATURES -- GLASS -- WATER-PROPANE |
S 45 Self-organized criticality and 1/f-noise at interacting nonequilibrium phase transitions / V. N. Skokov, A. V. Reshetnikov, V. P. Koverda, V. P. Koverda, A. V. Vinogradov // Physica A. - 2001. - Vol.293, № 1-2. - С. 1-12 Рубрики: ФИЗИКА Кл.слова (ненормированные): SELF-ORGANIZED CRITICALITY -- 1/f FLUCTUATIONS -- POWER SPECTRA Аннотация: Oscillatory combustion regimes were experimentally investigated under the conditions of ignitable liquid boiling-up before the reaction front. Fluctuations with a power spectral density inversely proportional to frequency (1/f-noise) were observed and the power-law character of distribution functions was found. The phenomena are connected with the intersection and interaction of nonequilibrium phase transitions. A mathematical model describing the initiation of 1/f fluctuations at the interaction of a subcritical phase transition and supercritical one in a space-distributed system was suggested |
1/f Fluctuations under acoustic cavitation of liquids / V. N. Skokov, V. P. Koverda, A. V. Reshetnikov, A. V. Vinogradov // Physica A. - 2006. - Vol.364. - С. 63-69 Рубрики: ФИЗИКА Кл.слова (ненормированные): SELF-ORGANIZED CRITICALITY -- ACOUSTIC CAVITATION -- NONEQUILIBRIUM CONDITIONS Аннотация: A regime of a generation of fluctuations with 1/f power spectra under cavitation of liquids in an ultrasonic field has been found experimentally. The acoustic cavitation is accompanied by the formation of various spatial structures and scale-invariant distribution functions of fluctuations. It has been shown that local fluctuations can have non-Gaussian distribution. A two-dimensional distributed parameter system of stochastic equations describing interacting nonequilibrium phase transitions has been investigated numerically. It has been shown that the system in a wide range of changing initial conditions and the intensity of external noise is characterized by the 1/f behavior of power spectra and scale-invariant distribution functions of fluctuations. The results of numerical simulation agree qualitatively with the experimental data |
B 73 Boiling up of jets of superheated ethanol-water solutions / A. V. Reshetnikov, A. V. Vinogradov, V. N. Begletsov, V. N. Skokov, V. P. Koverda // Journal of Engineering Thermophysics. - 2007. - Vol.16, №4. - С. 244-248 Рубрики: ФИЗИКА Кл.слова (ненормированные): EVOLUTION OF THE SHAPES -- SUPERHEATED AQUEOUS SOLUTIONS -- LOW-BOILING LIQUID Аннотация: The stability and evolution of the shapes of jets of strongly superheated aqueous solutions of ethanol flowing out of a high-pressure chamber are experimentally investigated at various initial parameters. It has been found that a low-boiling liquid causes shifting to lower temperatures of the boundaries between various kinds of boiling-up jets, such as cylindrical, conical, and open. Large-scale pulsations of the jet shapes are observed in the temperature range from 454 to 484 K, where the jet completely breaks down. The conditions for the formation of large-scale low-frequency pulsations with a power spectrum diverging inversely proportional to the frequency f (1/f spectra) have been revealed. Such fluctuations prove that the flow is unstable and large-scale low-frequency ejections are possible |
V 70 Vinogradov, A. V. Spectral Characteristics of Fluctuations in Ultrasonic Cavitation of Water and Glycerin / A. V. Vinogradov // Heat Transfer Research. - 2008. - Vol.39, №6. - С. 519-527 Рубрики: ФИЗИКА Кл.слова (ненормированные): FLUCTUATION -- ACOUSTIC CAVITATION -- GLYCERIN Аннотация: The results of experimental investigation of the dynamics of fluctuations in acoustic cavitation of water and glycerin are presented. Near the radiator surface the structures in interacting vapor-gas bubbles having the form of fractal clusters were formed. Using the method of photometric scanning of transmitted laser radiation, the dynamics of fluctuations was investigated. In the transient regime the range of the power of fluctuations changed inversely proportional to frequency. The distributions of local fluctuations differ from Gaussian ones and reveal the properties of scale invariance. The qualitative behavior of the frequency dependence of the spectral density of fluctuations on change in the power of an ultrasonic radiator was investigated. It is shown that the raise of the high-frequency boundary of the flicker behavior point to the buildup of instability and may serve as a precursor of possible large-scale overshoots |
D 98 Dynamics of transition processes and structure formation in critical heat-mass transfer regimes during liquid boiling and cavitation / A. N. Pavlenko, V. P. Koverda, A. V. Skokov, A. V. Reshetnikov, A. V. Vinogradov, A. S. Surtaev // Journal of Engineering Thermophysics. - 2009. - Vol.18, №1. - С. 20-38 Рубрики: ФИЗИКА Кл.слова (ненормированные): CRITICAL PHENOMENA -- FALLING FILMS -- LIQUID CAVITATION Аннотация: The results of experimental studies concerning the development of critical phenomena and structure formation in the process of boiling in falling films and during liquid cavitation are given. In conditions of stepwise and periodic pulsed surges of a thermal load, the parameters of formed metastable regular structures and critical parameters of heat-releasing surface drying are shown to be determined by the dynamics of moving wetting boundaries in the process of system self-organization. In the case of high-intensity heat fluxes, decomposition of a falling film is determined by propagation regimes of self-maintaining boiling fronts with a complex shape of intermediate structures. The study of ultrasonic cavitation of water, glycerin, and vacuum oil shows that structures of interacting gas-vapor bubbles (having the form of fractal clusters) are formed near the emitter surface. Spatial structures are characterized by a low-frequency divergence of the power spectra and a scale-invariant function of the fluctuation distributions. The experimental results are in good qualitative agreement with the numerical simulations performed within the theory of 1/f fluctuations in the case of nonequilibrium phase transitions in a spatially distributed system \\\\expert2\\NBO\\Journal of Engineering Thermophysics\\2009, V.18, N 1. P. 20-38.pdf |
L 95 Low-frequency fluctuations with 1/f α power spectrum in transient modes of water boiling on a wire heater [Electronic resource] / V. N. Skokov, V. P. Koverda, A. V. Vinogradov, A. V. Reshetnikov // High Temperature. - 2010. - Vol.48, №5. - P706-712 Рубрики: ФИЗИКА Кл.слова (ненормированные): CRITICAL EXPONENT -- DYNAMIC SCALING -- POWER LAW Аннотация: The investigation of transient modes of water boiling on a wire heater reveals the presence of random vibrations with the frequency dependence of power spectra of S ∼ f -α, where the exponent α has values in the range 0.8 ≤ α < 2. Large-scale low-frequency fluctuations exhibiting the property of scale invariance, the duration of which is distributed by the power law P ∼ τ-β, are present in experimental realizations of random processes describing thermal fluctuations. The properties of such fluctuation processes are described using two nonlinear stochastic differential equations which describe the interaction between different phase transitions. Relations of dynamic scaling are determined between the critical exponents which define the frequency dependence of the power spectra of fluctuations α and of the distribution function of the amplitudes of extreme low-frequency fluctuations β. It is demonstrated that the critical exponents are related by the relation α + β = 2 both in the experiments and in the theoretical model of interacting phase transitions. The power spectra of fluctuations are determined in the experiments with greater simplicity and accuracy than the distribution function of extreme amplitudes. In the cases where only the spectral dependence of power spectra of fluctuations is known, the correlations between the exponents enable one to obtain information about the distribution of large-scale surges and estimate dangerous amplitudes |
L 95 Low frequency fluctuations of laser beam intensity run through the system of cavitation water clusters [Electronic resource] / V. N. Skokov, V. P. Koverda, A. V. Vinogradov, A. V. Reshetnikov // Thermophysics and Aeromtchanics. - 2010. - Vol.17, №1. - P99-106. - Bibliogr. : p. 106 (21 ref.) Рубрики: ФИЗИКА Кл.слова (ненормированные): ACOUSTIC CAVITATION -- LOW-FREQUENCY PULSATIONS -- POWER SPECTRUM Аннотация: Experiments on water cavitation in ultrasonic field have been carried out. Low frequency fluctuations of the intensity of laser beam run through the cavitation area have been studied. Experiments have proved presence of low-frequency random fluctuations with frequency dependence of power spectra S ~ 1/ f , α where the exponent α ranged within 0.8 ≤ α ≤ 1.2. From experimental realizations, large-scale low frequency pulsations characterized by scale invariance, which duration is distributed according to the power law, have been distinguished. The results are explained on the basis of mathematical model for the rise of scale invariant fluctuations with 1/ f α power spectrum in the system of two nonlinear stochastic differential equations describing interaction of heterogeneous phase transitions. Distribution of extreme low frequency emissions obtained from numerical solutions to stochastic equations takes the power series form. Correlations of dynamic scaling between critical indicators determining frequency dependence of pulsations power spectra α and distribution functions of extreme low frequency pulsation amplitudes β have been determined. It is shown that both in the experiments on acoustic cavitation of water and in the theoretical model of interacting phase transitions critical indicators are bound with the correlation α + β = 2. Spectra of fluctuation power are determined in the experiments simpler and more accurately than the function of extreme amplitudes distribution. In case when only one frequency dependence of fluctuation capacity spectra is known correlations between indicators serve to obtain information on the distribution of large scale emissions and to estimate critical amplitudes. \\\\expert2\\NBO\\Thermophysics and Aeromechanics\\2010, V. 17, N 1. P. 99-106.pdf |
F 17 Faizullin, M. Z. Formation of clathrate hydrates under crystallization of gas-saturated amorphous ice [Electronic resource] / M. Z. Faizullin, A. V. Vinogradov, V. P. Koverda // International Journal of Heat and Mass Transfer. - 2013. - Vol.65. - С. 649-654. - Bibliogr. : p. 654 (42 ref.) Рубрики: ФИЗИКА Кл.слова (ненормированные): CLATHRATE HYDRATE -- KINETICS -- METHANE Аннотация: Layers of methane-saturated amorphous ice were obtained by deposition of molecular beams of water and gas on a substrate cooled with liquid nitrogen. Their heating is accompanied by glass transition (softening) and subsequent spontaneous crystallization. The avalanche-type initiation of crystallization centers captures the gas molecules and does not lead to their displacement by the motion of the crystallization front. Under crystallization of amorphous water-gas condensates in conditions of deep metastability the formation of gas hydrates takes place. Glass-transition and crystallization temperatures of the condensates were determined by changes in their dielectric properties under heating. The method of differential thermal analysis has been used to investigate the kinetics of crystallization of amorphous water layers. Properties that characterize the water crystallization kinetics have been determined on the basis of the obtained data on the dependence of the crystallization temperature on the heating rate \\\\expert2\\NBO\\International Journal of Heat and Mass Transfer\\2013, v.65, p.649-654.pdf |
K 79 Koverda, V. P. Stability of low-frequency pulsations in a transient heat transfer regime upon phase transitions [Electronic resource] / V. P. Koverda, V. N. Skokov, A. V. Vinogradov // High Temperature. - 2013. - Vol.51, №3. - P421-425. - Bibliogr. : p. 425 (20 ref.) Рубрики: ФИЗИКА Кл.слова (ненормированные): HARMONIC FORCE -- LOW-FREQUENCY PULSATIONS -- HEAT-MASS TRANSFER Аннотация: Using the principle of maximum entropy, we investigate the stability of stochastic processes with the 1/f power spectrum in the system of two nonlinear stochastic differential equations when modeling pulsations in crisis and transient heat-mass transfer regimes with intensive phase transitions. An analysis of the stability of the resultant process, which appears upon the interaction of the stochastic process and the 1/f spectrum of external deterministic impact, is performed. Under the action of harmonic force, stable resultant processes are divided into two types depending on the amplitude of the harmonic force. We have experimentally studied the influence of harmonic impact on the stability of pulsations with the 1/f spectrum upon the crisis of water boiling on a heated wire. The results are in qualitative agreement with theoretical estimations \\\\expert2\\NBO\\High Temperature\\2013, v. 51, N 3, p.421-425.pdf |
F 17 Faizullin, M. Z. Preparation of gas hydrates by nonequilibrium condensation of molecular beams / M. Z. Faizullin, A. V. Vinogradov, V. P. Koverda // Technical Physics Letters . - 2013. - Vol.39, №9. - С. 783-786. - Bibliogr. : p. 786 (16 ref.) Рубрики: ФИЗИКА Кл.слова (ненормированные): CARBON DIOXIDE -- CRYSTALLIZATION TEMPERATURES -- DIELECTRIC PROPERTIES Аннотация: Layers of amorphous ice saturated with carbon dioxide were prepared by the deposition of molecular beams of water and gas onto a substrate cooled with liquid nitrogen. Their heating is accompanied by glass transition (softening) and subsequent spontaneous crystallization. The glass transition and crystallization temperatures were determined from the change in dielectric properties during heating. The heat effects of the transformations were detected using differential thermal analysis. The crystallization of amorphous layers under conditions of deep metastability leads to the formation of crystalline hydrates. The avalanche nucleation of crystallization sites captures the gas molecules; therefore, they are not displaced by the movement of the crystallization front |
F 76 Formation of gas hydrate during crystallization of ethane-saturated amorphous ice / M. Z. Faizullin, A. V. Vinogradov, V. N. Skokov, V. P. Koverda // Russian Journal of Physical Chemistry A. - 2014. - Vol.88, №10. - С. 1706-1711. - Bibliogr. : p. 1710-1711 (24 ref.) Рубрики: ФИЗИКА Кл.слова (ненормированные): AMORPHOUS ICE -- CRYSTALLIZATION -- VITRIFICATION Аннотация: Layers of ethane-saturated amorphous ice were prepared by depositing molecular beams of water and gas on a substrate cooled with liquid nitrogen. The heating of the layers was accompanied by vitrification (softening) followed by spontaneous crystallization. Crystallization of condensates under the conditions of deep metastability proceeded with gas hydrate formation. The vitrification and crystallization temperatures of the condensates were determined from the changes in their dielectric properties on heating. The thermal effects of transformations were recorded by differential thermal analysis. The crystallization of the amorphous water layers was studied by electron diffraction. Formation of a metastable packing with elements of a cubic diamond-like structure was noted \\\\expert2\\nbo\\Russian Journal of Physical Chemistry A, Focus on Chemistry\\2014, V.88, N 10, p.1706.pdf |
F 17 Faizullin, M. Z. Properties of gas hydrates formed by nonequilibrium condensation of molecular beams [Electronic resource] / M. Z. Faizullin, A. V. Vinogradov, V. P. Koverda // High Temperature. - 2014. - Vol. 52, № 6. - С. 830-839. - Bibliogr. : p. 838-839 (36 ref.) Рубрики: ФИЗИКА Кл.слова (ненормированные): GLASS-TRANSITION -- AMORPHOUS SOLIDS -- AQUEOUS-SOLUTIONS Аннотация: Low-temperature crystallization of amorphous materials has been analyzed theoretically taking into account nonstationary nucleation. The kinetics of crystallization of amorphous water layers, formed by depositing molecular beams on a substrate cooled by liquid nitrogen, has been investigated by differential thermal analysis. The conditions of gas hydrate formation in low-temperature amorphous-ice layers saturated with carbon dioxide have been studied. The glass-transition and crystallization temperatures of the gas hydrates have been determined from the change in dielectric properties upon heating. Under the deep-metastability conditions, crystallization of water-gas layers leads to the formation of crystallohydrates. Gas molecules are captured by the avalanche-like nucleation of crystallization centers and, therefore, are not displaced by the moving crystal-melt interface. Gas-hydrate samples formed in nonequilibrium water-gas layers are convenient for studying their thermophysical properties \\\\expert2\\nbo\\High Temperature\\2014, v. 52, N 6, p.830-839.pdf |
V 70 Vinogradov, A. V. Stochastic resonant response in the transient boiling regime with periodic heat release [Electronic resource] / A. V. Vinogradov, V. N. Skokov, V. P. Koverda // Doklady Physics. - 2014. - Vol. 59, № 10. - С. 449-452. - Bibliogr. : p. 452 (15 ref.) Рубрики: ФИЗИКА Кл.слова (ненормированные): NOISE Аннотация: Results of experimental investigation into thermal pulsations with a transition from the bubble to the film boiling regime of water in a wire heater with periodic Joule release are presented. The intermittency of the bubble and film regimes was observed with the frequencies of the periodic current component lower than 0.1 Hz. The amplitude of thermal pulsations increased by a factor of approximately 4 in this case. These results are interpreted as the stochastic resonant response of the system when the periodic component of pul sations increases in the presence of noise. \\\\expert2\\nbo\\Doklady Physics\\2014, v.59, N 10, p.449-452.pdf |
S 86 Stochastic resonance at nonequilibrium phase transitions [Electronic resource] / V. N. Skokov, V. P. Koverda, A. V. Vinogradov, A. V. Reshetnikov // Physica A. - 2015. - Vol. 430, Article number 15968. - С. 65-72. - Bibliogr. : p. 71-72 (27 ref.) Рубрики: ФИЗИКА Кл.слова (ненормированные): 1/f-NOISE -- NONEQUILIBRIUM PHASE TRANSITIONS -- BOILING CRISIS Аннотация: Abstract Thermal pulsations in a transition from a nucleate to a film regime of water boiling on a wire heater with a periodic Joule heat release have been studied experimentally. At frequencies of the periodic action smaller than 0.1 Hz the intermittency of the nucleate and film boiling regimes was observed. In this case the amplitude of thermal pulsations increased. The experiments with an additional noise source were carried out. With an increase in the intensity of the noise the power of the output periodic mode increased and reaching the maximum began to decrease. The results are interpreted as stochastic resonance when the periodic component of pulsations increases in the presence of noise. The results show that in a complex system with nonequilibrium phase transitions there can occur both the extreme fluctuations with 1/f power spectrum and stochastic resonance under external periodic action. \\\\expert2\\nbo\\Physica A\\2015, v. 430, p.65-72.pdf |
F 17 Faizullin, M. Z. Hydrate formation in layers of gas-saturated amorphous ice [Electronic resource] / M. Z. Faizullin, A. V. Vinogradov, V. P. Koverda // Chemical Engineering Science. - 2015. - Vol. 130. - С. 135-143. - Bibliogr. : p. 142-143 (44 ref.) Рубрики: ФИЗИКА Кл.слова (ненормированные): AMORPHOUS ICE -- GAS HYDRATES -- CARBON DIOXIDE Аннотация: Layers of amorphous ice saturated with methane, ethane, propane and carbon dioxide were obtained by condensation of molecular beams of rarefied vapor and gas on a substrate cooled with liquid nitrogen. The amorphous state of such objects at low temperatures is stabilized by the high viscosity and the small value of the stationary nucleation rate of the crystal phase. Their heating in condition of high metastability is accompanied by spontaneous explosive crystallization, which leads to the formation of gas hydrates. Glass-transition and crystallization temperatures were determined by changes in their dielectric properties under heating. An increase in the gas content in layers of amorphous ice causes an increase in the crystallization temperature without any significant changes in the glass transition temperature. At atmospheric pressure in a liquid n-pentane medium the retention of gas hydrates was observed up to temperatures close to 273. K. Self-preservation ensured the retention of hydrates in a metastable state at temperatures exceeding considerably their equilibrium dissociation temperatures. Samples of gas hydrates obtained at a maximum gas flow rate during the deposition contained up to 15 mass % of methane, 12 mass % of ethane, 13 mass % of propane, and 23 mass % of carbon dioxide \\\\expert2\\nbo\\Chemical Engineering Science\\2015, v.130, p.135-143.pdf |
О-42 1/f-Noisa under Conditions of Interaction between Phase Transitions [] / V. N. Skokov, A. V. Reshetnikov, V. P. Koverda, A. V. Vinogradov // High Temperature. - 2001. - Vol. 39, N 2. - С. 296-301: il. - Bibliogr.: p. 321 (13 n.) Рубрики: ФИЗИКА Кл.слова (ненормированные): 1/f-NOISE -- PHASE TRANSITIONS \\\\Expert2\\NBO\\High Temperature\\2001, v.39, p.316.pdf |