SO(5) superconductor in a Zeeman magnetic field: Phase diagram and thermodynamic properties

In this paper we present calculations of the SO(5) quantum rotor theory of high-T$_{c}$ superconductivity in Zeeman magnetic field. We use the spherical approach for five-component quantum rotors in three-dimensional lattice to obtain formulas for critical lines, free energy, entropy and specific heat and present temperature dependences of these quantities for different values of magnetic field. Our results are in qualitative agreement with relevant experiments on high-T$_{c}$ cuprates.Comment: 4 pages, 2 figures, to appear in Phys. Rev. B, see http://prb.aps.or

Transition in a numerical model of contact line dynamics and forced dewetting

We investigate the transition to a Landau-Levich-Derjaguin film in forced dewetting using a quadtree adaptive solution to the Navier-Stokes equations with surface tension. We use a discretization of the capillary forces near the receding contact line that yields an equilibrium for a specified contact angle $\theta_\Delta$ called the numerical contact angle. Despite the well-known contact line singularity, dynamic simulations can proceed without any explicit additional numerical procedure. We investigate angles from $15^\circ$ to $110^\circ$ and capillary numbers from $0.00085$ to $0.2$ where the mesh size $\Delta$ is varied in the range of $0.0035$ to $0.06$ of the capillary length $l_c$. To interpret the results, we use Cox's theory which involves a microscopic distance $r_m$ and a microscopic angle $\theta_e$. In the numerical case, the equivalent of $\theta_e$ is the angle $\theta_\Delta$ and we find that Cox's theory also applies. We introduce the scaling factor or gauge function $\phi$ so that $r_m = \Delta/\phi$ and estimate this gauge function by comparing our numerics to Cox's theory. The comparison provides a direct assessment of the agreement of the numerics with Cox's theory and reveals a critical feature of the numerical treatment of contact line dynamics: agreement is poor at small angles while it is better at large angles. This scaling factor is shown to depend only on $\theta_\Delta$ and the viscosity ratio $q$. In the case of small $\theta_e$, we use the prediction by Eggers [Phys. Rev. Lett., vol. 93, pp 094502, 2004] of the critical capillary number for the Landau-Levich-Derjaguin forced dewetting transition. We generalize this prediction to large $\theta_e$ and arbitrary $q$ and express the critical capillary number as a function of $\theta_e$ and $r_m$. An analogy can be drawn between $r_m$ and the numerical slip length.Comment: This version of the paper includes the corrections indicated in Ref. [1

Biologia de Cinara pinivora (Hemoptera: Aphididae), em duas temperaturas, em laboratório.

Organizado por Patrícia Póvoa de Mattos, Celso Garcia Auer, Paulo César Botosso e Rejane Stumpf Sberze

A momentum-conserving, consistent, Volume-of-Fluid method for incompressible flow on staggered grids

The computation of flows with large density contrasts is notoriously difficult. To alleviate the difficulty we consider a consistent mass and momentum-conserving discretization of the Navier-Stokes equation. Incompressible flow with capillary forces is modelled and the discretization is performed on a staggered grid of Marker and Cell type. The Volume-of-Fluid method is used to track the interface and a Height-Function method is used to compute surface tension. The advection of the volume fraction is performed using either the Lagrangian-Explicit / CIAM (Calcul d'Interface Affine par Morceaux) method or the Weymouth and Yue (WY) Eulerian-Implicit method. The WY method conserves fluid mass to machine accuracy provided incompressiblity is satisfied which leads to a method that is both momentum and mass-conserving. To improve the stability of these methods momentum fluxes are advected in a manner "consistent" with the volume-fraction fluxes, that is a discontinuity of the momentum is advected at the same speed as a discontinuity of the density. To find the density on the staggered cells on which the velocity is centered, an auxiliary reconstruction of the density is performed. The method is tested for a droplet without surface tension in uniform flow, for a droplet suddenly accelerated in a carrying gas at rest at very large density ratio without viscosity or surface tension, for the Kelvin-Helmholtz instability, for a falling raindrop and for an atomizing flow in air-water conditions

Di-μ-acetato-bis­(dimethyl­formamide)­penta­kis­(μ-N,2-dioxidobenzene-1-car­boximidato)tetra­kis­(1-ethyl­imidazole)­penta­manganese(III)­manganese(II)–diethyl ether–dimethyl­foramide–methanol–water (1/1/1/1/0.12)

The title compound [Mn6(C7H4NO3)5(CH3CO2)2(C5H8N2)4(C3H7NO)2]·(C2H5)2O·C3H7NO·CH3OH·0.12H2O, abbreviated as MnII(OAc)2[15-MCMnIII(N)shi-5](EtIm)4(DMF)2·diethyl ether·DMF·MeOH·0.12H2O (where −OAc is acetate, MC is metallacrown, shi3− is salicylhydroximate, EtIM is n-ethylimidazole, DMF is N,N-dimethylformamide, and MeOH is methanol) contains five MnIII ions as members of the metallacrown ring and an MnII ion bound in the central cavity. The central MnII ion is seven-coordinate with a distorted face-capped trigonal–prismatic geometry. The five MnIII ions of the metallacrown ring are six-coordinate with distorted octa­hedral geometries. The configuration of the MnIII ions about the metallacrown ring follow a ΔΛΔPP pattern, with P representing planar. The four 1-ethyl­imidazole ligands are bound to four different MnIII ions. A diethyl ether solvent mol­ecule was found to be disordered over two mutually exclusive sites with an occupancy ratio of 0.568 (7):0.432 (7). A methanol solvent mol­ecule was found to be disordered over two mutually exclusive sites by being hydrogen bonded either to a dimethyl­formamide solvent mol­ecule (major occupancy component) or to an O atom of the main mol­ecule (minor occupancy component). The occupancy ratio refined to 0.678 (11):0.322 (11). Associated with the minor component is a partially occupied water mol­ecule [total occupancy 0.124 (15)]

Relativity and the lead-acid battery

The energies of the solid reactants in the lead-acid battery are calculated ab initio using two different basis sets at non-relativistic, scalar relativistic, and fully relativistic levels, and using several exchange-correlation potentials. The average calculated standard voltage is 2.13 V, compared with the experimental value of 2.11 V. All calculations agree in that 1.7-1.8 V of this standard voltage arise from relativistic effects, mainly from PbO2 but also from PbSO4