N 89 Novruzov, A. N. Computer study of the absorption of ethane by aqueous ultradispersed medium: IR spectra [Текст] / A. N. Novruzov, O. R. Rakhmanova, A. E. Galashev // Colloid Journal (Translation of Kolloidnyi Zhurnal). - 2008. - Vol. 70, № 1. - С. 55-63 Рубрики: ФИЗИКА Кл.слова (ненормированные): IR SPECTRA Аннотация: Absorption of ethane molecules by water clusters containing 10–20 molecules is studied by the molecular dynamics method. The (H2O) n (I), C2H6(H2O) n (II), and (C2H6)2(H2O) n (III) cluster systems are composed on the basis of specific statistical weights. Spectral characteristics of system and single clusters are determined in the frequency range of 0 меньше либо равно омега меньше либо равно 1000 cm в степени -1. In this frequency range, both real and imaginary parts of dielectric permittivity decrease monotonically after the absorption of C2H6 molecules by an aqueous ultradispersed system. Integral coefficient of IR absorption increases, while average (over frequency) reflection coefficient decreases after the absorption of ethane molecules. The intensity of IR scattering by the systems of clusters containing C2H6 molecules lowers. Maximal values of radiation power for water clusters with various sizes are balanced with the capture of ethane molecules by the clusters, whereas oscillations in the size dependence of the density of electrons that are active with respect to IR radiation decrease. \\\\Expert2\\NBO\\Colloid Journal\\2008, V.70, N 1, 55.pdf |
N 89 Novruzova, O. A. Numerical simulation of IR absorption, reflection, and scattering in dispersed water-oxygen media [Текст] / O. A. Novruzova, A. E. Galashev // High Temperature. - 2008. - Vol. 46, № 1. - С. 60-68 Рубрики: ФИЗИКА Кл.слова (ненормированные): IR ABSORPTION Аннотация: The method of molecular dynamics along with the flexible model of molecules are used to study the spectral characteristics of systems of clusters of (H2O) n , (O2) m (H2O) n , and (O) i (H2O) n , m меньше либо равно 2, i меньше либо равно 4, 10 меньше либо равно n меньше либо равно 50. It is demonstrated that the integral intensity of absorption of IR radiation decays after water clusters adsorb oxygen. In addition, the adsorption of oxygen causes a significant decrease in the reflection coefficient R of monochromatic IR radiation. In so doing, the R(?) spectrum splits into bands and exhibits seven peaks in the frequency region of 0 меньше либо равно омега меньше либо равно 3500 cm в степени -1. The dissociation of oxygen molecules captured by clusters makes the peaks of R(омега) spectrum more resolved. The attachment of molecular oxygen by clusters leads to decay of the power of their IR radiation, while the capture of atomic oxygen, on the contrary, is accompanied by an increase in the rate of dissipation of energy accumulated by water aggregates. \\\\Expert2\\NBO\\High Temperature\\2008, v.46, p.60.pdf |
N 89 Novruzova, O. A. IR spectra of aqueous disperse systems adsorbed atmospheric gases: 1. Nitrogen [Текст] / O. A. Novruzova, A. A. Galasheva, A. E. Galashev // Colloid Journal (Translation of Kolloidnyi Zhurnal). - 2007. - Vol. 69, № 4. - С. 474-482 Рубрики: ФИЗИКА Кл.слова (ненормированные): IR SPECTRA Аннотация: Spectral characteristics of (H2O) i , N2(H2O) i , and (N2)2(H2O) i cluster systems, where 10 меньше либо равно i меньше либо равно 50, are studied in the 0 меньше либо равно эпсилон меньше либо равно 3500 cm в степени -1 frequency range with the molecular dynamics method on the basis of a flexible molecule model. After nitrogen is captured by an aqueous disperse system, the absorption of the IR radiation by this system increases owing to the enhancement of intramolecular vibrations. In general, the reflection of the outer IR radiation by nitrated aqueous disperse systems is attenuated; however, when the nitrogen concentration increases twofold, there is a tendency toward an increase in the fraction of reflected radiation. As the nitrogen concentration in a system of water clusters rises, the power of radiation emitted by the system increases significantly and the number of electrons interacting with the outer IR radiation decreases. \\\\Expert2\\NBO\\Colloid Journal\\2007, V.69, N4,474.pdf |
A 10 A computer study of the absorption of infrared radiation by systems of molecular clusters [Текст] / A. N. Novruzov, V. N. Chukanov, O. R. Rakhmanova, A. E. Galashev // High Temperature. - 2006. - Vol. 44, № 6. - С. 932-940 Рубрики: ФИЗИКА Кл.слова (ненормированные): MOLECULAR CLASTERS Аннотация: The method of molecular dynamics is used to investigate the process of absorption of N2O and CH4 molecules by water clusters and to determine the frequency spectra of permittivity for systems consisting of clusters mixed in different ratios, namely, (H2O)n, (N2O)i(H2O)10, and (CH4)i(H2O)10. IR-radiation absorption spectra for these systems are calculated and analyzed; the radiation power scattered by these systems and the tangent of dielectric loss angle are determined. The inclusion of anharmonicity of phonon oscillation makes it possible to explain the origin of characteristic frequencies appearing in IR spectra of mixtures of cluster systems. The capture of molecules of greenhouse gases by an ultradisperse aqueous medium affects the ability of this medium to absorb terrestrial radiation, i.e., reduces the greenhouse effect. \\\\Expert2\\NBO\\High Temperature\\2006, v.44, p.932.pdf |
G 15 Galashev, A. E. Dielectric characteristics of O2(H2O)i and (O2)2(H2O)i clusters. Computer-aided experiment [Текст] / A. E. Galashev, V. N. Chukanov, O. A. Galasheva // Colloid Journal (Translation of Kolloidnyi Zhurnal). - 2006. - Vol. 68, № 2. - С. 131-136 Рубрики: ФИЗИКА Кл.слова (ненормированные): DIELECTRIC CONSTANT Аннотация: Absorption of oxygen molecules by water clusters with sizes of 10 меньше либо равно i меньше либо равно 50 is studied by the molecular dynamics method using the modified TIP4P model. It is revealed that the total dipole moment of the clusters nonmonotonically increases with their sizes. Absorption of O2 molecules tends to raise the static permittivity of the ultradispersed medium formed by the clusters. The real and imaginary parts of the permittivity of water clusters with absorbed O2 molecules are aperiodic functions of frequency. The permittivity components turn out to be nonmonotonic functions of cluster sizes. The IR absorption and reflectance spectra are calculated for clusters of pure water and aggregates with absorbed O2 molecules. After the addition of oxygen molecules, the absorption coefficient of the clusters decreases, while the reflection coefficient increases. It is concluded that the capture of oxygen molecules by atmospheric moisture may reduce the greenhouse effect. \\\\Expert2\\NBO\\Colloid Journal\\2006, V.68, N2,131.pdf |
G 15 Galashev, A. E. Computer Simulation of the Stability of Water Clusters Containing Nitrogen Oxide Molecules [Текст] / A. E. Galashev, V. N. Chukanov // Colloid Journal (Translation of Kolloidnyi Zhurnal). - 2004. - Vol. 66, № 5. - С. 523-530 Рубрики: ФИЗИКА Кл.слова (ненормированные): WATER CLUSTERS Аннотация: The stability of water clusters containing nitrogen oxide molecules is studied by the molecular dynamics method. The composition and size of thermodynamically stable heteroclusters are determined. The inclusion of two molecules of nitrogen oxide into aggregates containing seven or more water molecule increases the cluster stability. The correlation between the stability of heteroclusters and the ratio of self-diffusion coefficients of molecules of different kinds is observed. The real part of the cluster permittivity is maximal in the vicinity of the frequency of 200 cm–1. The inclusion of nitrogen oxide molecules into water clusters increases the characteristic frequency of dielectric relaxation. In general, heteroclusters are more stable with respect to perturbations caused by an external electric field than pure clusters with the same number of water molecules. The clusterization of water vapors accompanied by absorption of polar molecules of impurity favors a decrease in the greenhouse effect. \\\\Expert2\\NBO\\Colloid Journal\\2004, V.66, N5,523.pdf |
A 71 Arc current fluctuation power spectra in the system of a solid metal electrode and carbonate melt [Текст] / A. V. Reshetnikov, V. N. Sannikov, V. N. Skokov, V. P. Koverda // Journal of Applied Mechanics and Technical Physics. - 2007. - Vol. 48, № 1. - С. 7-10 Рубрики: ФИЗИКА Кл.слова (ненормированные): SOLID METALS Аннотация: Arc current fluctuations between a solid metal electrode and a liquid melt of alkaline carbonates at atmospheric pressure are measured. Arc current fluctuation power spectra are determined from the measurement data. It is shown that the fluctuation power is inversely proportional to the frequency (1/f-fluctuations). The fluctuations have a normal Gaussian distribution. The observed 1/f fluctuations exhibit scale invariance. \\\\Expert2\\NBO\\Journal of Applied Mechanics and Technical Physics\\2007, v. 48, N. 1, p.7.pdf |
S 68 Smolyak, B. M. Influence of a variable magnetic field on the stability of the magnetic suspension of high-T-c superconductors [] / B. M. Smolyak, M. V. Babanov, G. V. Ermakov // Technical Physics. - 1997. - V.42, Is.12. - С. 1455-1456 Рубрики: ФИЗИКА Кл.слова (ненормированные): FIELD VARIABLE -- FIELD MAGNETIC -- SUSPENSION MAGNETIC -- SUPERCONDUCTORS HIGH-T-C -- LEVITATION -- COLLAPSE -- AMPLITUDE CRITICAL -- FREQUENCY Аннотация: The resonant oscillation of superconductors by a variable magnetic held during hard levitation and the collapse of levitation are investigated. The critical amplitude and the frequency of the variable held are calculated \\\\Expert2\\NBO\\Technical Physics\\1997, v.42, N 12, p.1455.pdf |
S 66 Skokov, V. N. Fluctuations with a 1/f(alpha) spectrum in film boiling [] / V. N. Skokov, V. P. Koverda, A. V. Reshetnikov // Jetp Letters. - 1999. - V. 69, N 8. - С. 636-639 Рубрики: ФИЗИКА Кл.слова (ненормированные): NONEQUILIBRIUM PHASE TRANSITIONS -- 1/f-NOISE Аннотация: 1/f and 1/f(2) noise were observed experimentally in film boiling of water on vertically oriented platinum heater. Fluctuations with a 1/f(alpha) spectrum were observed in a wide range of controlling parameters and seen over five orders of magnitude in frequency. It was noted that the process investigated is similar to the phenomenon of self-organized criticality |
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?? |
K 79 Koverda, V. P. Statistics of fluctuations with a 1/f spectrum at phase transitions in a spatially distributed system / V. P. Koverda, V. N. Skokov // Physica A. - 2011. - Vol. 390, № 13. - С. 2468-2479 Рубрики: ФИЗИКА Кл.слова (ненормированные): 1/f-NOISE -- FIRST PASSAGE TIME -- AVALANCHES Аннотация: A study has been made on the statistics of fluctuations in a spatially distributed system, which describes the interaction of nonequilibrium phase transitions. It is shown that at a certain intensity of external white noise acting on phase transitions, the time and spatial spectra of fluctuations have power laws S(f)∼f−α and S(k)∼k−γ. The dependence of the exponents α and γ on the value of the diffusion coefficient determining the spatial interaction of fluctuations have been found. Extreme low-frequency fluctuations has been revealed and distribution functions of their duration P(τ)∼τ−β and size P(s)∼s−ν have been determined. It has been found that the exponent α of the frequency dependence of time spectra and the exponent β of the distribution function of the fluctuation duration are related by the relation α+β=2. The exponent of the spatial spectrum γ and the exponent of the size distribution function ν are related by a similar relation: γ+ν=2. The results of experimental studies on fluctuations in a typical nonequilibrium phase transition such as transient modes of water boiling on a wire heater are presented. It was demonstrated that the critical exponents, which describe the power dependence of power spectra of fluctuations and the amplitude distribution of extreme surges, are related by the relation α+β=2 both in experiments and in the theoretical model of interacting heterogeneous phase transitions |
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 |
K 79 Koverda, V. P. The origin of 1/f fluctuations and scale transformations of time series at nonequilibrium phase transitions / V. P. Koverda, V. N. Skokov // Physica A. - 2005. - Vol.346, №3-4. - С. 203-216 Рубрики: ФИЗИКА Кл.слова (ненормированные): FLUCTUATIONS -- POWER SPECTRA -- NONEQUILIBRIUM PHASE TRANSITIONS Аннотация: Investigations of the dynamics of heat and mass transfer show that in crisis and transient conditions one can observe high-energy fluctuations with a power spectrum inversely proportional to the frequency (flicker or 1/f fluctuations). Such a spectrum presupposes energy transient from high to lower frequency modes and the possibility of large-scale catastrophic events in a system. Theory shows that such fluctuations arise in a system owing to the simultaneous progress of interacting phase transitions in the presence of a white noise of sufficient intensity. The distributions functions of fluctuations during scale transformations of a system of stochastic equations describing the 1/f noise generations have been investigated. It is shown that the Gaussian distributions of a random process with a 1/f spectrum under a roughness of a scale change to exponential distribution characteristic of the statistics of extreme events. The probability of such events should be taken into account in predicting the stability of different heat transfer regimes |
K 79 Koverda, V. P. Statistics of low-frequency pulsations in critical regimes of heat mass exchange with phase transitions / V. P. Koverda, V. N. Skokov, A. V. Reshetnikov // Journal of Engineering Thermophysics. - 2007. - Vol.16, №3. - С. 130 -138 Рубрики: ФИЗИКА Кл.слова (ненормированные): FLUCTUATION -- IRREGULAR HIGH-ENERGY -- 1 / F СПЕКТРЫ Аннотация: Experimental investigation of fluctuation dynamics in critical and transitional modes of heat mass exchange shows existence of irregular high-energy pulsations with power spectrum inversely proportional to the frequency—so called 1/f spectrum. Such regimes are characterized by the fact that an essential part of the pulsations energy is connected with very slow processes and mean that large high-energy bursts are possible in the system. Another characteristic feature of such regimes is scale invariance of the fluctuations distribution function. According to the theory, the 1/f fluctuations can emerge in physical systems due to simultaneous phase transitions in presence of sufficiently intensive white noise. This paper is devoted to detailed investigation of relaxation processes at steadying of stationary stochastic process in non-equilibrium phase transitions in system of two nonlinear stochastic differential equation. Such an information reveals statistical patterns of particular large-scale low-frequency bursts. Discontinuous “forgetting” of the initial conditions takes place. It is shown by numerical methods that distributions of duration and maximal values of the low-frequency extreme bursts have the power-like form. Experimental investigation results of statistical characteristics of fluctuation processes at ultrasonic cavitation and flash boiling of overheated water jets are presented. Results of the experiments carried out fit conclusions of the theoretical model for interacting heterogeneous phase transitions |
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 |
S 68 Smolyak, B. M. The effect of ac magnetic fields on the lifting power of levitating superconductors / B. M. Smolyak, G. V. Ermakov, L. I. Chubraeva // Superconductor Science and Technology. - 2007. - Vol.20, №4. - С. 406-411 Рубрики: ФИЗИКА Кл.слова (ненормированные): LEVITATION FORCE -- SUPERCONDUCTING SUSPENSION -- LIFTING FORCE Аннотация: This study deals with the decrease in the levitation force under the action of an ac field up to the frequency at which oscillations of the superconducting suspension are limited by inertia. The lifting force was measured as a function of the ac field amplitude and the exposure time. It was shown that the force quickly decreased at the moment the ac field was applied and then continued diminishing, but at a lower rate. A qualitative model was proposed, taking into account two effects of the ac field on the magnetization of the levitating superconductor: a complete destruction of the critical state in some section of the superconductor (to a depth λac) and the initiation of a faster magnetic relaxation in the region where the induction gradient is preserved |
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 |
K 79 Koverda, V. P. Statistics of avalanches in stochastic processes with a 1/fα spectrum / V. P. Koverda, V. N. Skokov // Physica A. - 2009. - Vol.388, №9. - С. 1804-1812 Рубрики: ФИЗИКА Кл.слова (ненормированные): 1/f-NOISE -- AVALANCHES -- FIRST PASSAGE TIME Аннотация: The results of numerical investigation of the Brownian motion in a two-dimensional potential field formed under the coupling of phase transitions at the conditions of the criticality induced by white noise are presented. The suggested system of stochastic equations at the white noise intensity that corresponds to the criticality of a noise-induced transition describes stationary random processes with power spectra S(f)∼f−α, where the exponent α varies in the range 0.8≤α≤1.8. The exponent α was found by the direct FFT method from numerical realizations of the Brownian motion processes. The exponent β of the distribution function P(τ)∼τ−β of the duration of low frequency extreme fluctuations was determined by numerical methods from the distributions of time of the first passage across a potential barrier with different realizations of white noise. The low frequency extreme fluctuations in many properties are similar to avalanches considered in models of self-organized criticality. The exponents α and β were determined directly from numerical realizations of random processes independently of each other. It is shown that the exponents α and β are related by the relation α+β=2. |
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 |