5,605 research outputs found
A PRODUCTION FUNCTION FOR FLORIDA FOLIAGE NURSERIES FROM TIME-SERIES AND CROSS-SECTION DATA
Crop Production/Industries,
Laser velocimeter for simultaneous two-dimensional velocity measurements
Laser velocimeter provides simultaneous orthogonal measurements in manner which minimizes many problems attending prior systems, and allows spatial traversing of flowfield in order to obtain velocity profiles. Velocimeter permits rapid interrogation of unsteady flows where area of interest is of the order of one meter in extent and flow does not vary appreciably over time of about one second
Quasi-Normal Modes of Brane-Localised Standard Model Fields
We present here a detailed study of the quasi-normal spectrum of
brane-localised Standard Model fields in the vicinity of D-dimensional
black-holes. A variety of such backgrounds (Schwarzschild, Reissner-Nordstrom
and Schwarzszchild-(Anti) de Sitter) are investigated. The dependence of the
quasi-normal spectra on the dimensionality D, spin of the field s, and
multipole number l is analyzed. Analytical formulae are obtained for a number
of limiting cases: in the limit of large multipole number for Schwarzschild,
Schwarzschild-de Sitter and Reissner-Nordstrom black holes, in the extremal
limit of the Schwarzschild-de Sitter black hole, and in the limit of small
horizon radius in the case of Schwarzschild-Anti de Sitter black holes. We show
that an increase in the number of hidden, extra dimensions results in the
faster damping of all fields living on the brane, and that the localization of
fields on a brane affects the QN spectrum in a number of additional ways, both
direct and indirect.Comment: 13 pages, 4 figures, to be published in Phys. Rev.
Development of a new laser Doppler velocimeter for the Ames High Reynolds Channel No. 2
A new two-channel laser Doppler velocimeter developed for the Ames High Reynolds Channel No. 2 is described. Design features required for the satisfactory operation of the optical system in the channel environment are discussed. Fiber optics are used to transmit the megahertz Doppler signal to the photodetectors located outside the channel pressure vessel, and provision is made to isolate the optical system from pressure and thermal strain effects. Computer-controlled scanning mirrors are used to position the laser beams in the channel flow. Techniques used to seed the flow with 0.5-micron-diam polystyrene spheres avoiding deposition on the test-section windows and porous boundary-layer removal panels are described. Preliminary results are presented with a discussion of several of the factors affecting accuracy
Machine-Checked Proofs For Realizability Checking Algorithms
Virtual integration techniques focus on building architectural models of
systems that can be analyzed early in the design cycle to try to lower cost,
reduce risk, and improve quality of complex embedded systems. Given appropriate
architectural descriptions, assume/guarantee contracts, and compositional
reasoning rules, these techniques can be used to prove important safety
properties about the architecture prior to system construction. For these
proofs to be meaningful, each leaf-level component contract must be realizable;
i.e., it is possible to construct a component such that for any input allowed
by the contract assumptions, there is some output value that the component can
produce that satisfies the contract guarantees. We have recently proposed (in
[1]) a contract-based realizability checking algorithm for assume/guarantee
contracts over infinite theories supported by SMT solvers such as linear
integer/real arithmetic and uninterpreted functions. In that work, we used an
SMT solver and an algorithm similar to k-induction to establish the
realizability of a contract, and justified our approach via a hand proof. Given
the central importance of realizability to our virtual integration approach, we
wanted additional confidence that our approach was sound. This paper describes
a complete formalization of the approach in the Coq proof and specification
language. During formalization, we found several small mistakes and missing
assumptions in our reasoning. Although these did not compromise the correctness
of the algorithm used in the checking tools, they point to the value of
machine-checked formalization. In addition, we believe this is the first
machine-checked formalization for a realizability algorithm.Comment: 14 pages, 1 figur
Time-dependent correlation functions in a one-dimensional asymmetric exclusion process
We study a one-dimensional anisotropic exclusion process describing particles
injected at the origin, moving to the right on a chain of sites and being
removed at the (right) boundary. We construct the steady state and compute the
density profile, exact expressions for all equal-time n-point density
correlation functions and the time-dependent two-point function in the steady
state as functions of the injection and absorption rates. We determine the
phase diagram of the model and compare our results with predictions from
dynamical scaling and discuss some conjectures for other exclusion models.Comment: LATEX-file, 32 pages, Weizmann preprint WIS/93/01/Jan-P
Antibodies to the Chlamydial 60 Kilodalton Heat Shock Protein in Women With Tubal Factor Infertility
Surveyor I Mission Report. Part III - Television Data
Surveyor I lunar photographs interpretation, and television subsyste
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