Channel distances and representation

The properties of several distance measures for discrete stationary channels with memory are studied. All are based on Ornstein's {if238-1}-random process distance. The strongest of these distances has been employed in a theory concerned with the approximation of {if238-1}-continuous conditionally almost block independent (CABI) channels by primitive and other simple models. Here the approximation with respect to the weaker distances and the equivalence of the weaker distances to the strongest is investigated. In addition, an exact representation of a {if238-3}-continuous CABI channel as an infinite sliding-block coding of the input joined with an I.I.D. noise source is developed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23849/1/0000088.pd

Baryon-Baryon Interactions in the Flavor SU(3) Limit from Full QCD Simulations on the Lattice

We investigate baryon-baryon (BB) interactions in the 3-flavor full QCD simulations with degenerate quark masses for all flavors. The BB potentials in the orbital S-wave are extracted from the Nambu-Bethe-Salpeter wave functions measured on the lattice. We observe strong flavor-spin dependences of the BB potentials at short distances. In particular, a strong repulsive core exists in the flavor-octet and spin-singlet channel (the 8_s representation), while an attractive core appears in the flavor singlet channel (the 1 representation). We discuss a relation of such flavor-spin dependence with the Pauli exclusion principle in the quark level. Possible existence of an H-dibaryon resonance above the Lambda-Lambda threshold is also discussed.Comment: 16 pages, 4 figures, ptptex.cls use

Disentangling Scaling Properties in Anisotropic and Inhomogeneous Turbulence

We address scaling in inhomogeneous and anisotropic turbulent flows by decomposing structure functions into their irreducible representation of the SO(3) symmetry group which are designated by $j,m$ indices. Employing simulations of channel flows with Re$_\lambda\approx 70$ we demonstrate that different components characterized by different $j$ display different scaling exponents, but for a given $j$ these remain the same at different distances from the wall. The $j=0$ exponent agrees extremely well with high Re measurements of the scaling exponents, demonstrating the vitality of the SO(3) decomposition.Comment: 4 page

Non-perturbative formulation of the static color octet potential

By dressing Polyakov lines with appropriate functionals of the gauge fields, we construct observables describing a fundamental representation static quark-antiquark pair in the singlet, adjoint and average channels of SU(N) pure gauge theory. Each of the potentials represents a gauge invariant eigenvalue of the Hamiltonian. Numerical simulations are performed for SU(2) in 2+1 dimensions. The adjoint channel is found to be repulsive at small and confining at large separations, suggesting the existence of a metastable (N^2-1)-plet bound state. For small distances and temperatures above the deconfinement transition, the leading order perturbative prediction for the ratio of singlet and adjoint potentials is reproduced by the lattice data.Comment: 10 pages, 3 figure

Role of river bathymetry in hydraulic modeling of river channels

Accurate geometric representation of the river channel is required for accurate hydraulic modeling of rivers. These are generally obtained through remote sensing techniques such as Light Detection and Ranging (LIDAR). However, these techniques lack the ability to model the submerged channel bed effectively and need to be complemented with surveyed bathymetric data for complete representation of the channel bathymetry, which can be time and cost prohibitive. An alternative to address this issue is to develop conceptual models that can estimate bathymetry. This study aims to evaluate the potential of a conceptual model, the River Channel Morphology Model (RCMM) which estimates the channel bathymetry by relating channel planform to channel bathymetry. Channel DEMs are estimated from RCMM based algorithms and compared with those estimated from LIDAR and interpolation based algorithms to evaluate the importance and applicability of RCMM. Each of the five channel DEMs is used to develop hydraulic models for three characteristic low and high flows. They are assessed to study the propagation of errors in channel DEM to the hydraulic outputs such as inundation maps, water surface elevation (WSE), flow velocity and shear. The analysis shows that the error in hydraulic modeling due to inaccurate bathymetric representation is significantly reduced by RCMM. The error in hydraulic model outputs decreases with increasing flow. The RCMM exhibits the ability to model channel bathymetry at reaches with reliable accuracy. Results indicate that the RCMM can even outperform bathymetry estimated from interpolation of surveyed data over large distances and, hence, is an admirable prospect for channel bathymetry estimation