4,882 research outputs found
A flight instrumentation system for acquisition of atmospheric turbulence data
A flight instrumentation system for the acquisition of atmospheric turbulence data is described. Airflow direction transducers and an impact pressure transducer are the primary instruments for measuring vertical and lateral gust velocity, and a sensitive incremental pressure transducer is used to measure longitudinal gust velocity. Airplane motions, sensed by an inertial platform, are subtracted from the primary measurements during postflight data reduction to yield true gust velocity time histories. Salient engineering features of the instrumentation are discussed, and a complete description of the instrumentation is presented
A navigation-aids identification decoder and display for general-aviation aircraft
Navigation-aids identification decoder and display device for general aviation aircraf
New aircraft instrument indicates turbulence intensity
System consists of accelerometer, indicator, and necessary electronic circuits for summing and averaging accelerations. Averaging-time feature enables pilot to see large values of accelerations over a short time or smaller accelerations over longer period of time
Alternative experimental evidence for chiral restoration in excited baryons
Given existing empirical spectral patterns of excited hadrons it has been
suggested that chiral symmetry is approximately restored in excited hadrons at
zero temperature/density (effective symmetry restoration). If correct, this
implies that mass generation mechanisms and physics in excited hadrons is very
different as compared to the lowest states. One needs an alternative and
independent experimental information to confirm this conjecture. Using very
general chiral symmetry arguments it is shown that strict chiral restoration in
a given excited nucleon forbids its decay into the N \pi channel. Hence those
excited nucleons which are assumed from the spectroscopic patterns to be in
approximate chiral multiplets must only "weakly" decay into the N \pi channel,
(f_{N^*N\pi}/f_{NN\pi})^2 << 1. However, those baryons which have no chiral
partner must decay strongly with a decay constant comparable with f_{NN\pi}.
Decay constants can be extracted from the existing decay widths and branching
ratios. It turnes out that for all those well established excited nucleons
which can be classified into chiral doublets N_+(1440) - N_-(1535), N_+(1710) -
N_-(1650), N_+(1720) - N_-(1700), N_+(1680) - N_-(1675), N_+(2220) - N_-(2250),
N_+(?) - N_-(2190), N_+(?) - N_-(2600), the ratio is (f_{N^*N\pi}/f_{NN\pi})^2
~ 0.1 or much smaller for the high-spin states. In contrast, the only well
established excited nucleon for which the chiral partner cannot be identified
from the spectroscopic data, N(1520), has a decay constant into the N\pi
channel that is comparable with f_{NN\pi}. This gives an independent
experimental verification of the chiral symmetry restoration scenario.Comment: 4 pp. A new footnote with an alternative proof of impossibility of
parity doublet decay into pi + N is added. To appear in Phys. Rev. Let
Literal readout of identification signals in Morse code
Instrument, designed for mounting in aircraft instrument panels, decodes identification signals received in Morse from VOR or ILS transmitters as they are received and displays the literal equivalent. Without elaboration it cannot decode numbers
Nuclear Forces and Few-Nucleon Studies Based on Chiral Perturbation Theory
After a brief review on the status of few--nucleon studies based on
conventional nuclear forces, we sketch the concepts of the effective field
theory approach constrained by chiral symmetry and its application to nuclear
forces. Then first results for few--nucleon observables are discussed.Comment: 8 pages, presented by W. Gloeckle at the International Symposium on
"A New Era of Nuclear Structure Physics", Kurokawa Village (Niigata Pref.),
Japan, Nov. 19-22, 200
Few-Nucleon Systems with Two-Nucleon Forces from Chiral Effective Field Theory
Nucleon-nucleon (NN) forces from chiral perturbation theory at
next-to-leading (NLO) and next-to-next-to-leading order (NNLO) are applied to
systems with two, three and four nucleons. At NNLO, we consider two versions of
the chiral potential which differ in the strength of the two-pion-exchange
(TPE) but describe two nucleon observables equally well. The NNLO potential
leads to unphysical deeply bound states in the low partial waves and effects of
the 3N forces, which appear first at this order, are expected to be large. We
provide arguments for a reduction of the TPE potential and introduce the NNLO*
version of the NN forces. We calculate nd scattering observables as well as
various properties of 3H and 4He with the NNLO* potential and find good
agreement with the data and with predictions based upon the standard
high-precision potentials. We find an improved description of the 3H and 4He
binding energies.Comment: 34 pages, 25 figure
Improving the convergence of the chiral expansion for nuclear forces II: Low phases and the deuteron
Recently, we have proposed a new cut-off scheme for pion loop integrals in the two-pion exchange potential. This method allows for a consistent implementation of constraints from pion-nucleon scattering and has been successfully applied to peripheral nucleon-nucleon partial waves. We now consider low partial waves in the non-perturbative regime, where the regularized Lippmann-Schwinger equation has to be solved in order to generate the bound and scattering states. We observe an improved description of most of the phase shifts when going from next-to- to next-to-next-to-leading order in the chiral expansion. We also find a good description of the deuteron properties. In addition, the new cut-off scheme allows to avoid the presence of unphysical deeply bound states. We discuss the cut-off dependence of the four-nucleon low-energy constants and show that their numerical values can be understood in terms of resonance saturation. This connects the effective field theory approach to boson exchange phenomenology
Cancel the deal? An experimental study on the exploitation of irrational consumers
Consumers can sometimes be exploited because they make mistakes in their valuation of products. We present the results from a large-scale experimental study that examines whether third-party spectators from the general population in the United States cancel a deal where a buyer has made a mistake in the valuation of a product and agreed to pay more for the product than the seller knows it is worth. We find that the majority of the spectators cancel such deals even when the seller’s involvement is limited to accepting a proposal made by the buyer. A substantial share of these spectators are also willing to fine the seller. However, a large minority of the spectators are willing to uphold the deal even when the seller has proposed the deal and obfuscated the information provided to the buyer. Our results shed new light on when people view market transactions as acceptable and their attitudes to government regulation of businesses
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