On integration of some classes of (n+1)(n+1) dimensional nonlinear Partial Differential Equations

The paper represents the method for construction of the families of particular solutions to some new classes of $(n+1)$ dimensional nonlinear Partial Differential Equations (PDE). Method is based on the specific link between algebraic matrix equations and PDE. Admittable solutions depend on arbitrary functions of $n$ variables.Comment: 6 page

Anomalous mass dependence of radiative quark energy loss in a finite-size quark-gluon plasma

We demonstrate that for a finite-size quark-gluon plasma the induced gluon radiation from heavy quarks is stronger than that for light quarks when the gluon formation length becomes comparable with (or exceeds) the size of the plasma. The effect is due to oscillations of the light-cone wave function for the in-medium $q\to gq$ transition. The dead cone model by Dokshitzer and Kharzeev neglecting quantum finite-size effects is not valid in this regime. The finite-size effects also enhance the photon emission from heavy quarks.Comment: 8 pages, 3 figure

Theoretical description of mixed film formation at the air/water interface : carboxylic acids–fatty amines

Thermodynamic parameters of mixed monolayer formation of aliphatic amines CnH2n+1NH2 and carboxylic acids CnH2n+1COOH (n = 6–16) are calculated using the quantum chemical semiempirical PM3 method. Four types of mixed dimers and tetramers amine–acid are considered. The total contribution of interactions between the hydrophilic parts of amine and acid into clusterization Gibbs energy is slightly lower than the corresponding interactions for individual surfactants. It suggests a synergetic interaction between the regarded amphiphilic compounds as proved by experimental data in the literature. Two types of competitive film formation are possible: mixed 2D film 1, where the molecules of the minor component are single distributed among the molecules of the prevailing second component (mixture of components on molecular level), and 2D film 2 with a domain structure comprised of pure component “islands” linked together. The dependence of the Gibbs energy of clusterization per monomer for 2D film 1 on the component mole fraction shows that the maximum synergetic effect is typical for the case that both surfactants have the same even number of carbon atoms in the hydrocarbon chain and form an equimolar mixture. Formation of 2D film 1 is more preferable than that of 2D film 2, if the difference of the hydrocarbon chain lengths is not larger than 5 methylene units. The limiting mole fraction of carboxylic acids in such mixed monolayers is 66.7%

The turbulent spectrum created by non-Abelian plasma instabilities

Recent numerical work on the fate of plasma instabilities in weakly-coupled non-Abelian gauge theory has shown the development of a cascade of energy from long to short wavelengths. This cascade has a steady-state spectrum, analogous to the Kolmogorov spectrum for turbulence in hydrodynamics or for energy cascades in other systems. In this paper, we theoretically analyze processes responsible for this cascade and find a steady-state spectrum f_k ~ k^-2, where f_k is the phase-space density of particles with momentum k. The exponent -2 is consistent with results from numerical simulations. We also discuss implications of the emerging picture of instability development on the "bottom-up" thermalization scenario for (extremely high energy) heavy ion collisions, emphasizing fundamental questions that remain to be answered.Comment: 17 pages, 5 figure

Gluon propagators and center vortices in gluon plasma

We study electric and magnetic components of the gluon propagators in quark-gluon plasma in terms of center vortices by using a quenched simulation of SU(2) lattice theory. In the Landau gauge, the magnetic components of the propagators are strongly affected in the infrared region by removal of the center vortices, while the electric components are almost unchanged by this procedure. In the Coulomb gauge, the time-time correlators, including an instantaneous interaction, also have an essential contribution from the center vortices. As a result, one finds that magnetic degrees of freedom in the infrared region couple strongly to the center vortices in the deconfinement phase.Comment: 12 pages, 11 figure

Estimation of synchronous generator participation in low-frequency oscillations damping based on synchronized phasor measurements

Large-scale centralized power systems interconnected by weak tie-lines is a typical feature of the state-of-the-industry power engineering. Another trend is distributed generation units integration with the resulting decrease of power system inertia constant and increasing sensitivity to small disturbances. In particular, in the case of significant power imbalance, periodic low-frequency oscillations of power system performance parameters may arise. Low frequency oscillations in power systems are inherently non-linear and non-stationary processes representing a superposition of numerous rotating masses movement components having mutual influence in a power region or power center. These situations imply the crucial role of monitoring each generator damping capability which is determined by the adjustment of the system regulators in use. To estimate the synchronous generator capability to maintain synchronous operation under deviating frequency and load angle conditions synchronizing torque and corresponding synchronizing power are proposed to be used. The possibility to determine the synchronous machine synchronizing power is subject to the presence of the load angle variation data with the techniques for defining load angle without direct measurement using a system of assumptions have been analyzed. Numerous simulations have shown that the effect of assumptions can be evaluated as acceptable. The main focus of the paper is the analysis of synchronizing power corresponding to the actual generator involved in the oscillations which had arisen after a disturbance in the Unified Energy System of Russia. The supposed cause of the oscillations is improper automatic excitation controller operation. © 2014 WIT Press.International Journal of Safety and Security Engineering;International Journal of Sustainable Development and Planning;WIT Transactions on Ecology and the Environmen

Dispersionless scalar integrable hierarchies, Whitham hierarchy and the quasi-classical dbar-dressing method

The quasi-classical limit of the scalar nonlocal dbar-problem is derived and a quasi-classical version of the dbar-dressing method is presented. Dispersionless KP, mKP and 2DTL hierarchies are discussed as illustrative examples. It is shown that the universal Whitham hierarchy it is nothing but the ring of symmetries for the quasi-classical dbar-problem. The reduction problem is discussed and, in particular, the d2DTL equation of B type is derived.Comment: LaTex file,19 page

Relative and center-of-mass motion in the attractive Bose-Hubbard model

We present first-principle numerical calculations for few particle solutions of the attractive Bose-Hubbard model with periodic boundary conditions. We show that the low-energy many-body states found by numerical diagonalization can be written as translational superposition states of compact composite systems of particles. These compact states break the translational symmetry of the problem and their center-of-mass and internal excitations offer simple explanations of the energy spectrum of the full model.Comment: 12 pages, 9 figure