Commutative Energetic Subsets of BCK-Algebras

The notions of a C-energetic subset and (anti) permeable C-value in BCK-algebras are introduced, and related properties are investigated. Conditions for an element t in [0, 1] to be an (anti) permeable C-value are provided. Also conditions for a subset to be a C-energetic subset are discussed. We decompose BCK-algebra by a partition which consists of a C-energetic subset and a commutative ideal

Permeable conformal walls and holography

We study conformal field theories in two dimensions separated by domain walls, which preserve at least one Virasoro algebra. We develop tools to study such domain walls, extending and clarifying the concept of `folding' discussed in the condensed-matter literature. We analyze the conditions for unbroken supersymmetry, and discuss the holographic duals in AdS3 when they exist. One of the interesting observables is the Casimir energy between a wall and an anti-wall. When these separate free scalar field theories with different target-space radii, the Casimir energy is given by the dilogarithm function of the reflection probability. The walls with holographic duals in AdS3 separate two sigma models, whose target spaces are moduli spaces of Yang-Mills instantons on T4 or K3. In the supergravity limit, the Casimir energy is computable as classical energy of a brane that connects the walls through AdS3. We compare this result with expectations from the sigma-model point of view.Comment: Latex file, 34 pages, 8 figures, uses JHEP3.cls. Typos corrected and references adde

First-order virial expansion of short-time diffusion and sedimentation coefficients of permeable particles suspensions

For suspensions of permeable particles, the short-time translational and rotational self-diffusion coefficients, and collective diffusion and sedimentation coefficients are evaluated theoretically. An individual particle is modeled as a uniformly permeable sphere of a given permeability, with the internal solvent flow described by the Debye-Bueche-Brinkman equation. The particles are assumed to interact non-hydrodynamically by their excluded volumes. The virial expansion of the transport properties in powers of the volume fraction is performed up to the two-particle level. The first-order virial coefficients corresponding to two-body hydrodynamic interactions are evaluated with very high accuracy by the series expansion in inverse powers of the inter-particle distance. Results are obtained and discussed for a wide range of the ratio, x, of the particle radius to the hydrodynamic screening length inside a permeable sphere. It is shown that for x >= 10, the virial coefficients of the transport properties are well-approximated by the hydrodynamic radius (annulus) model developed by us earlier for the effective viscosity of porous-particle suspensions

Ethanol-water separation by pervaporation

The separation of ethanol-water mixtures is of great importance for the production of ethanol from biomass. Both ultrafiltration and pervaporation processes can be used for the continuous processing of fermentation and separation, The removal of ethanol from the ultrafiltration permeate can be accomplished by pervaporation. Separation of ethanol-water mixtures by the pervaporation process has been investigated. Results are presented for membranes which are preferentially permeable for ethanol and for others which are preferentially water permeable. Details on the preparation of several membrane types (homogeneous, asymmetric and composite) are given. A schematic process diagram is given in which the fermentation of sugars to ethanol is membrane-controlled