11,099 research outputs found
-analog of the XXZ chain with a boundary
We study analog of the XXZ spin chain with a boundary
magnetic field h. We construct explicit bosonic formulas of the vacuum vector
and the dual vacuum vector with a boundary magnetic field. We derive integral
formulas of the correlation functions.Comment: 24 pages, LaTEX2
Oscillation Frequency Dependence of Non-Classical Rotation Inertia of Solid He
The non-classical rotational inertia fraction of the identical cylindrical
solid He below 300 mK is studied at 496 and 1173 Hz by a double resonance
torsional oscillator. Below 35 mK, the fraction is the same at sufficiently low
rim velocities. Above 35 mK, the fraction is greater for the higher than the
lower mode. The dissipation peak of the lower mode occurs at a temperature
4 mK lower than that of the higher mode. The drive dependence of the two
modes shows that the reduction of the fraction is characterized by critical
velocity, \textit{not} amplitude nor acceleration.Comment: 4 pages, 4 figure
Aerodynamic preliminary analysis system. Part 2: User's manual and program description
A comprehensive aerodynamic analysis program based on linearized potential theory is described. The solution treats thickness and attitude problems at subsonic and supersonic speeds. Three dimensional configurations with or without jet flaps having multiple nonplanar surfaces of arbitrary planform and open or closed slender bodies or noncircular contour are analyzed. Longitudinal and lateral-directional static and rotary derivative solutions are generated. The analysis is implemented on a time sharing system in conjunction with an input tablet digitizer and an interactive graphics input/output display and editing terminal to maximize its responsiveness to the preliminary analysis problem. Nominal case computation time of 45 CPU seconds on the CDC 175 for a 200 panel simulation indicates the program provides an efficient analysis for systematically performing various aerodynamic configuration tradeoff and evaluation studies
Generation of Curvature Perturbations with Extra Anisotropic Stress
We study the evolution of curvature perturbations and the cosmic microwave
background (CMB) power spectrum in the presence of an hypothesized extra
anisotropic stress which might arise, for example, from the dark radiation term
in brane-world cosmology. We evolve the scalar modes of such perturbations
before and after neutrino decoupling and analyze their effects on the CMB
spectrum. A novel result of this work is that the cancellation of the neutrino
and extra anisotropic stress could lead to a spectrum of residual curvature
perturbations which is similar to the observed CMB power spectrum. This implies
a possible additional consideration in the determination of cosmological
parameters from the CMB analysis.Comment: 13 pages, 2 figures; improved discussio
Hydrothermal Ethanol Flames in Co-Flow Jets
Results on the autoignition and stabilization of ethanol hydrothermal flames in a Supercritical Water Oxidation (SCWO) reactor operating at constant pressure are reported. The flames are observed as luminous reaction zones occurring in supercritical water; i.e., water at conditions above its critical point (approximately 22 MPa and 374 C). A co-flow injector is used to inject fuel (inner flow), comprising an aqueous solution ranging from 20%-v to 50%-v ethanol, and air (annular flow) into a reactor filled with supercritical water at approximately 24.3 MPa and 425 C. Results show hydrothermal flames are autoignited and form diffusion flames which exhibit laminar and/or turbulent features depending upon flow conditions. Two orthogonal camera views are used; one providing a backlit shadowgraphic image of the co-flow jet and the other providing color images of the flame. In addition, spectroscopic measurements of flame emissions in the UV and visible spectrum are discussed
Data dependent energy modelling for worst case energy consumption analysis
Safely meeting Worst Case Energy Consumption (WCEC) criteria requires
accurate energy modeling of software. We investigate the impact of instruction
operand values upon energy consumption in cacheless embedded processors.
Existing instruction-level energy models typically use measurements from random
input data, providing estimates unsuitable for safe WCEC analysis.
We examine probabilistic energy distributions of instructions and propose a
model for composing instruction sequences using distributions, enabling WCEC
analysis on program basic blocks. The worst case is predicted with statistical
analysis. Further, we verify that the energy of embedded benchmarks can be
characterised as a distribution, and compare our proposed technique with other
methods of estimating energy consumption
Neutrino mass effects on vector and tensor CMB anisotropies in the presence of a primordial magnetic field
If a primordial magnetic field (PMF) is present during photon decoupling and
afterward, a finite neutrino mass can affect all modes of the CMB. In this
work, we expand on earlier studies of the scalar mode effects by constructing
the vector and tensor mode equations in the presence of massive neutrinos and a
PMF. We compute the power spectrum of the various modes in an illustrative
example and find that the neutrino mass can significantly affect the vector and
tensor modes when a PMF exists, while the effects are negligible for no PMF.
The most prominent result of the present analysis is the behavior of the EE
component of the tensor mode at low multipoles. For massive neutrinos the EE
mode can become comparable to the observed primary anisotropy. Therefore, if
and when the EE mode power spectrum is measured at low multipoles the
possibility exists to place a strong constraint on the sum of the neutrino
masses.Comment: 11 pages, 8 figure
The Integrals of Motion for the Deformed W-Algebra II: Proof of the commutation relations
We explicitly construct two classes of infinitly many commutative operators
in terms of the deformed W-algebra , and give proofs of the
commutation relations of these operators. We call one of them local integrals
of motion and the other nonlocal one, since they can be regarded as elliptic
deformation of local and nonlocal integrals of motion for the algebra.Comment: Dedicated to Professor Tetsuji Miwa on the occasion on the 60th
birthda
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