Modeling the burnout of solid polydisperse fuel under the conditions of external heat transfer

A self-similar burnout mode of solid polydisperse fuel is considered taking into consideration heat transfer between fuel particles, gases, and combustion chamber walls. A polydisperse composition of fuel is taken into account by introducing particle distribution functions by radiuses obtained for the kinetic and diffusion combustion modes. Equations for calculating the temperatures of particles and gases are presented, which are written for particles average with respect to their distribution functions by radiuses taking into account the fuel burnout ratio. The proposed equations take into consideration the influence of fuel composition, air excess factor, and gas recirculation ratio. Calculated graphs depicting the variation of particle and gas temperatures, and the fuel burnout ratio are presented for an anthracite-fired boiler. © 2013 Pleiades Publishing, Inc

Cobalt(II) and copper(II) complexes with carboxylic acids, imidazole, and 2-methylimidazole

The compositions of [MIm(MeIm)x]L complexes synthesized by the reaction of cobalt(II) and copper(II) fumarates ML · nH2O with imidazole (Im) and 2-methylimidazole (MeIm) were determined. The thermal decomposition of the salts was analyzed, and the pyridine nitrogen atom of imidazole and the oxygen atoms of carboxyl anions were shown to participate in complexation using electronic absorption spectra and IR spectra. The composition and stability of cobalt(II) and copper(II) imidazolatesuccinate complexes in an aqueous solution were determined photometrically and spectrophotometrically, and their higher stability in comparison with monoligand complexes was demonstrated

Spectrum of boundary states in the open Hubbard chain

We use the Bethe Ansatz solution for the one dimensional Hubbard model with open boundary conditions and applied boundary fields to study the spectrum of bound states at the boundary. Depending on the strength of the boundary potentials one finds that the true ground state contains a single charge or, for boundary potentials comparable to the Hubbard interaction, a pair of electrons in a bound state. If these are left unoccupied one finds holon and spinon bound states. We compute the finite size corrections to the low lying energies in this system and use the predictions of boundary conformal field theory to study the exponents related to the orthogonality catastrophe.Comment: LaTeX + epsf,amssymb macros, 14 pp. incl. figure

Direct Calculation of Breather S Matrices

We formulate a systematic Bethe-Ansatz approach for computing bound-state (``breather'') S matrices for integrable quantum spin chains. We use this approach to calculate the breather boundary S matrix for the open XXZ spin chain with diagonal boundary fields. We also compute the soliton boundary S matrix in the critical regime.Comment: 23 pages, LaTeX, 1 eps figur

Integrable open boundary conditions for the Bariev model of three coupled XY spin chains

The integrable open-boundary conditions for the Bariev model of three coupled one-dimensional XY spin chains are studied in the framework of the boundary quantum inverse scattering method. Three kinds of diagonal boundary K-matrices leading to nine classes of possible choices of boundary fields are found and the corresponding integrable boundary terms are presented explicitly. The boundary Hamiltonian is solved by using the coordinate Bethe ansatz technique and the Bethe ansatz equations are derived.Comment: 21 pages, no figure

Magnetic susceptibility and low-temperature specific-heat of integrable 1-D Hubbard model under open-boundary conditions

The magnetic susceptibility and the low-temperature specific heat of the 1-dimensional Hubbard model under the integrable open-boundary conditions are discussed through the Bethe ansatz with the string hypothesis. The contributions of the boundary fields to both the susceptibility and the specific heat are obtained, and their exact expressions are analytically derived.Comment: 14 pages, Latex, No figures, to appear in J. Phys. A: Gen. & Mat

Kondo effect in a quantum critical ferromagnet

We study the Heisenberg ferromagnetic spin chain coupled with a boundary impurity. Via Bethe ansatz solution, it is found that (i) for J>0, the impurity spin behaves as a diamagnetic center and is completely screened by 2S bulk spins in the ground state, no matter how large the impurity spin is; (ii) The specific heat of the local composite (impurity plus 2S bulk spins which form bound state with it) shows a simple power law $C_{loc}\sim T^{3/2}$. (iii)For J<0, the impurity is locked into the critical behavior of the bulk. Possible phenomena in higher dimensions are discussed.Comment: 6page Revtex, no figure, final version in PRB, Jun 1 issue, 199

Ghost spins and novel quantum critical behavior in a spin chain with local bond-deformation

We study the boundary impurity-induced critical behavior in an integrable SU(2)-invariant model consisting of an open Heisenberg chain of arbitrary spin-$S$ (Takhatajian-Babujian model) interacting with an impurity of spin $\vec{S'}$ located at one of the boundaries. For $S=1/2$ or $S'=1/2$, the impurity interaction has a very simple form $J\vec{S}_1\cdot\vec{S'}$ which describes the deformed boundary bond between the impurity $\vec{S'}$ and the first bulk spin $\vec{S}_1$ with an arbitrary strength $J$. With a weak coupling $0<J<J_0/[(S+S')^2-1/4]$, the impurity is completely compensated, undercompensated, and overcompensated for $S=S'$, $S>S'$ and $S<S'$ as in the usual Kondo problem. While for strong coupling $J\geq J_0/[(S+S')^2-1/4]$, the impurity spin is split into two ghost spins. Their cooperative effect leads to a variety of new critical behaviors with different values of $|S'-S|$.Comment: 16 pages revtex, no figur