3,309 research outputs found
BOD:COD Ratio as an Indicator for Pollutants Leaching from Landfill
The relationship of BOD to COD of leachate from a mature landfill site are investigated over a period of six years to determine the indicator to be used for prediction of leachate characteristic generating from landfill site. Results of the investigation reveal that BOD:COD ratio is a good indicator of degradation of organic matter in landfill. It can be used as an indicator for degradation of organic matter that differentiate the acetogenic phase from methanogenic phase in this landfill
Two-Dimensional Vortex Lattice Melting
We report on a Monte-Carlo study of two-dimensional Ginzburg-Landau
superconductors in a magnetic field which finds clear evidence for a
first-order phase transition characterized by broken translational symmetry of
the superfluid density. A key aspect of our study is the introduction of a
quantity proportional to the Fourier transform of the superfluid density which
can be sampled efficiently in Landau gauge Monte-Carlo simulations and which
satisfies a useful sum rule. We estimate the latent heat per vortex of the
melting transition to be where is the melting
temperature.Comment: 10 pages (4 figures available on request), RevTex 3.0, IUCM93-00
Tunneling gap of laterally separated quantum Hall states
We use a method of matched asymptotics to determine the energy gap of two
counter-propagating, strongly interacting, quantum Hall edge states. The
microscopic edge state dispersion and Coulomb interactions are used to
precisely constrain the short-distance behavior of an integrable field theory,
which then determines the low energy spectrum. We discuss the relationship of
our results to the tunneling measurements of Kang et al., Nature 403, 59
(2000).Comment: 4 pages, 1 figur
Heavy quark mass determination from the quarkonium ground state energy: a pole mass approach
The heavy quark pole mass in perturbation theory suffers from a renormalon
caused, inherent uncertainty of . This fundamental
difficulty of determining the pole mass to an accuracy better than the inherent
uncertainty can be overcome by direct resummation of the first infrared
renormalon. We show how a properly defined pole mass as well as the mass for the top and bottom quarks can be determined accurately from the
quarkonium ground state energy.Comment: 16 pages; published versio
Two-to-one resonant multi-modal dynamics of horizontal/inclined cables. Part I : theoretical formulation and model validation
This paper is first of the two papers dealingwith analytical investigation of resonant multimodal dynamics due to 2:1 internal resonances in the finite-amplitude free vibrations of horizontal/inclined cables. Part I deals with theoretical formulation and validation of the general cable model. Approximate nonlinear partial differential equations of 3-D coupled motion of small sagged cables - which account for both spatio-temporal variation of nonlinear dynamic tension and system asymmetry due to inclined sagged configurations - are presented. A multidimensional Galerkin expansion of the solution ofnonplanar/planar motion is performed, yielding a complete set of system quadratic/cubic coefficients. With the aim of parametrically studying the behavior of horizontal/inclined cables in Part II [25], a second-order asymptotic analysis under planar 2:1 resonance is accomplished by the method of multiple scales. On accounting for higher-order effectsof quadratic/cubic nonlinearities, approximate closed form solutions of nonlinear amplitudes, frequencies and dynamic configurations of resonant nonlinear normal modes reveal the dependence of cable response on resonant/nonresonant modal contributions. Depending on simplifying kinematic modeling and assigned system parameters, approximate horizontal/inclined cable models are thoroughly validated by numerically evaluating statics and non-planar/planar linear/non-linear dynamics against those of the exact model. Moreover, the modal coupling role and contribution of system longitudinal dynamics are discussed for horizontal cables, showing some meaningful effects due to kinematic condensation
Edge and Bulk of the Fractional Quantum Hall Liquids
An effective Chern-Simons theory for the Abelian quantum Hall states with
edges is proposed to study the edge and bulk properties in a unified fashion.
We impose a condition that the currents do not flow outside the sample. With
this boundary condition, the action remains gauge invariant and the edge modes
are naturally derived. We find that the integer coupling matrix should
satisfy the condition (: filling of Landau
levels, : the number of gauge fields ) for the quantum Hall liquids. Then
the Hall conductance is always quantized irrespective of the detailed dynamics
or the randomness at the edge.Comment: 13 pages, REVTEX, one figure appended as a postscript fil
Strongly correlated fermions with nonlinear energy dispersion and spontaneous generation of anisotropic phases
Using the bosonization approach we study fermionic systems with a nonlinear
dispersion relation in dimension d>2. We explicitly show how the band curvature
gives rise to interaction terms in the bosonic version of the model. Although
these terms are perturbatively irrelevant in relation to the Landau Fermi
liquid fixed point, they become relevant perturbations when instabilities take
place. Using a coherent state path integral technique we built up the effective
action that governs the dynamics of the Fermi surface fluctuations. We consider
the combined effect of fermionic interactions and band curvature on possible
anisotropic phases triggered by negative Landau parameters. In particular we
study in some detail the phase diagram for the isotropic/nematic/hexatic
quantum phase transition.Comment: RevTeX4, 9 pages, 2 eps figures, Final version as appeared in
Phys.Rev.
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