355 research outputs found

    Simplified actor analysis for a case of developing renewable energy

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    Domestic fuels and renewables constitute less than 5% in the fuel balance of the Sverdlovsk region. However, the potential of renewables, including biomass, is higher. Some rural cottages and villages can be supplied with renewables placed around them. This paper describes the main actors in the field of developing renewable energy in the Sverdlovsk region, gives their classification (individual micro-scale consumers, joined small and mid-scale consumers, and other “actors”) and presents their desired behaviour. As a conclusion, the paper offers one of the possible ways to force the development of renewable energy by using an “inverse infrastructure” approach. © 2014 WIT Press.International Journal of Sustainable Development and Planning;WIT Transactions on Ecology and the Environmen

    Theory of transverse spin dynamics in a polarized Fermi liquid and an itinerant ferromagnet

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    The linear equations for transverse spin dynamics in a weakly polarized degenerate Fermi liquid with arbitrary relationship between temperature and polarization are derived from Landau-Silin phenomenological kinetic equation with general form of two-particle collision integral. Unlike the previous treatment where Fermi velocity and density of states have been taken as constants independent of polarization here we made derivation free from this assumption. The obtained equations are applicable for description of spin dynamics in paramagnetic Fermi liquid with finite polarization as well in an itinerant ferromagnet. In both cases transverse spin wave frequency is found to be proportional to the square of the wave vector with complex constant of proportionality (diffusion coefficient) such that the damping has a finite value at T=0. The polarization dependence of the diffusion coefficient is found to be different for a polarized Fermi liquid and for an itinerant ferromagnet. These conclusions are confirmed by derivation of transverse spin wave dispersion law in frame of field theoretical methods from the integral equation for the vortex function. It is shown that similar derivation taking into consideration the divergency of static transverse susceptibility also leads to the same attenuating spin wave spectrum.Comment: 7 pages, no figure

    True Dielectric and Ideal Conductor in Theory of the Dielectric Function for Coulomb System

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    On the basis of the exact relations the general formula for the static dielectric permittivity e(q,0) for Coulomb system is found in the region of small wave vectors q. The obtained formuladescribes the dielectric function e(q,0) of the Coulomb system in both states in the "metallic" state and in the "dielectric" one. The parameter which determines possible states of the Coulomb system - from the "true" dielectric till the "ideal" conductor is found. The exact relation for the pair correlation function for two-component system of electrons and nuclei g_ei(r) is found for the arbitrary thermodynamic parameters.Comment: 5 pages, no figure

    Comment on ``Damping of energetic gluons and quarks in high-temperature QCD''

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    Burgess and Marini have recently pointed out that the leading contribution to the damping rate of energetic gluons and quarks in the QCD plasma, given by γ=cg2ln(1/g)T\gamma=c g^2\ln(1/g)T, can be obtained by simple arguments obviating the need of a fully resummed perturbation theory as developed by Braaten and Pisarski. Their calculation confirmed previous results of Braaten and Pisarski, but contradicted those proposed by Lebedev and Smilga. While agreeing with the general considerations made by Burgess and Marini, I correct their actual calculation of the damping rates, which is based on a wrong expression for the static limit of the resummed gluon propagator. The effect of this, however, turns out to be cancelled fortuitously by another mistake, so as to leave all of their conclusions unchanged. I also verify the gauge independence of the results, which in the corrected calculation arises in a less obvious manner.Comment: 5 page

    Linear theory of nonlocal transport in a magnetized plasma

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    A system of nonlocal electron-transport equations for small perturbations in a magnetized plasma is derived using the systematic closure procedure of V. Yu. Bychenkov et al., Phys. Rev. Lett. 75, 4405 (1995). Solution to the linearized kinetic equation with a Landau collision operator is obtained in the diffusive approximation. The Fourier components of the longitudinal, oblique, and transversal electron fluxes are found in an explicit form for quasistatic conditions in terms of the generalized forces: the gradients of density and temperature, and the electric field. The full set of nonlocal transport coefficients is given and discussed. Nonlocality of transport enhances electron fluxes across magnetic field above the values given by strongly collisional local theory. Dispersion and damping of magnetohydrodynamic waves in weakly collisional plasmas is discussed. Nonlocal transport theory is applied to the problem of temperature relaxation across the magnetic field in a laser hot spot.Comment: 27 pages, 13 figure

    Quantum Well Based on Graphene and Narrow-Gap Semiconductors

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    We consider the energy spectrum of the planar quantum well which consisted of two ribbons of narrow-gap semiconductors and a graphene ribbon between ones. It is shown that the gapless mode appears only in case of inverted narrow-gap semiconductors. Spin splitting of the energy spectrum for a nonsymmetric quantum well is calculated taking into account a specificity of graphene. We investigate interface states and optical transitions. It is shown that the optical transitions are possible only with a conservation of a parity.Comment: 13 pages, 2 figures, 1 tabl

    High Temperature Response Functions and the Non-Abelian Kubo Formula

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    We describe the relationship between time-ordered and retarded response functions in a plasma. We obtain an expression, including the proper iϵi\epsilon-prescription, for the induced current due to hard thermal loops in a non-Abelian theory, thus giving the non-Abelian generalization of the Kubo formula. The result is closely related to the eikonal for a Chern-Simons theory and is relevant for a gauge-invariant description of Landau damping in the quark-gluon plasma at high temperature.Comment: 14 pages in LaTeX, MIT CTP #2205 and CU-TP #59
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