44,017 research outputs found
Statistics of some atmospheric turbulence records relevant to aircraft response calculations
Methods for characterizing atmospheric turbulence are described. The methods illustrated include maximum likelihood estimation of the integral scale and intensity of records obeying the von Karman transverse power spectral form, constrained least-squares estimation of the parameters of a parametric representation of autocorrelation functions, estimation of the power spectra density of the instantaneous variance of a record with temporally fluctuating variance, and estimation of the probability density functions of various turbulence components. Descriptions of the computer programs used in the computations are given, and a full listing of these programs is included
Experiments shed new light on nickel-fluorine reactions
Isotopic tracer experiments and scale-impingement experiments show fluorine to be the migrating species through the nickel fluoride scale formed during the fluorination of nickel. This is in contrast to nickel oxide scales, where nickel is the migrating species
A Corollary for Nonsmooth Systems
In this note, two generalized corollaries to the LaSalle-Yoshizawa Theorem
are presented for nonautonomous systems described by nonlinear differential
equations with discontinuous right-hand sides. Lyapunov-based analysis methods
are developed using differential inclusions to achieve asymptotic convergence
when the candidate Lyapunov derivative is upper bounded by a negative
semi-definite function
A video display interface for the LORAN-C navigation receiver development system
A microprocessor-based development system was designed and fabricated for prototype test of navigation receiver designs. During use of this system in the development of low-cost LORAN-C receiver/processor concepts, the limitations of the integral KIM-1 display were severely felt. It was to augment this numerical display that the video character display was produced. The circuit design presented meets the need for a flexible-format display capable of driving a small standard video monitor with only minimal demands upon microprocessor memory and MPU cycles
Testing and evaluation of solid lubricants for gas bearings
The testing and results of testing solid film lubricants for gas lubricated bearing applications are reported. The tests simulated operational hazards of tilting pad gas bearings. The presence of a low coefficient of friction and the endurance of the solid film lubricant were the criteria for judging superior performance. All solid lubricants tested were applied to a plasma sprayed chrome oxide surface. Molybdenum disulfide and graphite fluoride were the solid lubricants tested; other test parameters included the method of application of the solid lubricant and the surface finish of the plasma sprayed coating. In general, the application of a solid film lubricant was found to significantly improve the coefficient of friction of the rubbing surfaces
Long-range beam-beam experiments in the relativistic heavy ion collider
Long-range beam-beam effects are a potential limit to the LHC performance
with the nominal design parameters, and certain upgrade scenarios under
discussion. To mitigate long-range effects, current carrying wires parallel to
the beam were proposed and space is reserved in the LHC for such wires. Two
current carrying wires were installed in RHIC to study the effect of strong
long-range beam-beam effects in a collider, as well as test the compensation of
a single long-range interaction. The experimental data were used to benchmark
simulations. We summarize this work.Comment: 12 pages, contribution to the ICFA Mini-Workshop on Beam-Beam Effects
in Hadron Colliders, CERN, Geneva, Switzerland, 18-22 Mar 201
A mesocosm experiment investigating the effects of substratum quality and wave exposure on the survival of fish eggs
In a mesocosm experiment, the attachment of bream (Abramis brama) eggs to spawning substrata with and without periphytic biofilm coverage and their subsequent survival with and without low-intensity wave exposure were investigated. Egg attachment was reduced by 73% on spawning substrata with a natural periphytic biofilm, compared to clean substrata. Overall, this initial difference in egg numbers persisted until hatching. The difference in egg numbers was even increased in the wave treatment, while it was reduced in the no-wave control treatment. Exposure to a low-intensity wave regime affected egg development between the two biofilm treatments differently. Waves enhanced egg survival on substrata without a biofilm but reduced the survival of eggs on substrata with biofilm coverage. In the treatment combining biofilm-covered substrata and waves, no attached eggs survived until hatching. In all treatments, more than 75% of the eggs became detached from the spawning substrata during the egg incubation period, an
Analytic structure of the Landau gauge gluon propagator
The results of different non-perturbative studies agree on a power law as the
infrared behavior of the Landau gauge gluon propagator. This propagator
violates positivity and thus indicates the absence of the transverse gluons
from the physical spectrum, i.e. gluon confinement. A simple analytic structure
for the gluon propagator is proposed capturing all of its features. We comment
also on related investigations for the Landau gauge quark propagator.Comment: 4 pages, 2 figures, talk given by R.A. at 6th Conference on Quark
Confinement and the Hadron Spectrum, Villasimius, Sardinia, Italy, 21-25 Sep
200
ZZE-Configuration of chromophore ß-153 in C-phycocyanin from Mastigocladus laminosus
The photochemistry of C-phycocyanin has been studied after denaturation in the dark. It shows
an irreversible reaction which has characteristics of a Ζ,Ζ,Ε- to Z,Z,Z-isomerization of dihydrobilins.
Its amplitude depends on the reaction conditions, with a maximum corresponding to 15%
conversion of one of the three PC chromophores. This chromophore is suggested to be ß-153, for
which recent X-ray data T. Schirmer, W. Bode, and R. Huber, J. Mol. Biol., submitted, show
ring D being highly twisted out of the plane of the other rings. During unfolding, there is thus a
probability of falling into the photochemically labile Z,Z,^-configuration
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