4,019 research outputs found
Magnetic Moments of Baryons with a Heavy Quark
We compute magnetic moments of baryons with a heavy quark in the bound state
approach for heavy baryons. In this approach the heavy baryon is considered as
a heavy meson bound to a light baryon. The latter is represented as a soliton
excitation of light meson fields. We obtain the magnetic moments by sandwiching
pertinent components of the electromagnetic current operator between the bound
state wave--functions. We extract this current operator from the coupling to
the photon field after extending the action to be gauge invariant.Comment: Talk presented by HW at MRST'03 (Joe-Fest), Syracuse, NY, May 2003,
12 pages, uses AIP style files. Ref. adde
Planet--planet scattering in circumstellar gas disks
Hydrodynamical simulations of two giant planets embedded in a gaseous disk
have shown that in case of a smooth convergent migration they end up trapped
into a mean motion resonance. These findings have led to the conviction that
the onset of dynamical instability causing close encounters between the planets
can occur only after the dissipation of the gas when the eccentricity damping
is over. We show that a system of three giant planets may undergo planet-planet
scattering when the gaseous disk, with density values comparable to that of the
Minimum Mass Solar Nebula, is still interacting with the planets. The
hydrodynamical code FARGO--2D--1D is used to model the evolution ofthe disk and
planets, modified to properly handle close encounters between the massive
bodies. Our simulations predict a variety of different outcomes of the
scattering phase which includes orbital exchange, planet merging and scattering
of a planet in a hyperbolic orbit. This implies thatthe final fate of a
multiplanet system under the action of the disk torques is not necessarily a
packed resonant configuration.Comment: Astronomy and Astrophysics Letters, in pres
On Norm-Based Estimations for Domains of Attraction in Nonlinear Time-Delay Systems
For nonlinear time-delay systems, domains of attraction are rarely studied
despite their importance for technological applications. The present paper
provides methodological hints for the determination of an upper bound on the
radius of attraction by numerical means. Thereby, the respective Banach space
for initial functions has to be selected and primary initial functions have to
be chosen. The latter are used in time-forward simulations to determine a first
upper bound on the radius of attraction. Thereafter, this upper bound is
refined by secondary initial functions, which result a posteriori from the
preceding simulations. Additionally, a bifurcation analysis should be
undertaken. This analysis results in a possible improvement of the previous
estimation. An example of a time-delayed swing equation demonstrates the
various aspects.Comment: 33 pages, 8 figures, "This is a pre-print of an article published in
'Nonlinear Dynamics'. The final authenticated version is available online at
https://doi.org/10.1007/s11071-020-05620-8
Vibrations measured in the passenger cabins of two jet transport aircraft
Accelerations in the lateral and vertical directions were measured at two locations on the floor of a three-jet-engine aircraft and at two locations on the floor of a two-jet-engine aircraft during a total of 13 flights, each of which included taxiing, takeoff, ascent, cruise, descent, and landing. Accelerations over the frequency range 0 to 25 Hz were recorded continuously on magnetic tape and were synchronized with the VGH recorders in the aircraft so that vibratory accelerations could be correlated with the operating conditions of the aircraft. From the results it was indicated that the methodology used in segmenting the data, which were obtained in a continuous and repetitive manner, contributes to establishing baseline data representative of the flight characteristics of aircraft. Significant differences among flight conductions were found to occur. The lateral accelerations were approximately 15 percent of the vertical accelerations during flight but as much as 50 to 100 percent of the vertical accelerations during ground operations. The variation between the responses of the two aircraft was not statistically significant. The results also showed that more than 90 percent of the vibratory energy measured during flight occurred in the 0- to 3.0-Hz frequency range. Generally, the vibration amplitudes were normally distributed
Ring baffle pressure distribution and slosh damping in large cylindrical tanks
An investigation was conducted to determine the pressure loads and damping associated with rigid ring baffles in relatively large cylindrical tanks. The radial and circumferential pressure distribution, as well as the damping, was measured on a ring baffle subjected to fundamental antisymmetric slosh in a 284-cm-diameter rigid tank. Experimental and analytical data are presented as a function of slosh velocity or amplitude, baffle spacing, and baffle locations both above and below the liquid surface. Results suggest that pressure distributions and damping values can be determined from available theories for the design of single and multiple baffle configurations
An Evaluation of Physical Disk I/Os for Complex Object Processing
In order to obtain the performance required for nonstandard database environments, a hierarchical complex object model with object references is used as a storage structure for complex objects. Several storage models for these complex objects, as well as a benchmark to evaluate their performance, are described. A cost model for analytical performance evaluation is developed, and the analytical results are validated by means of measurements on the DASDBS, complex object storage system. The results show which storage structures for complex objects are the most efficient under which circumstance
Investigation of slosh anomaly in Apollo lunar module propellant gage
Analysis of propellant sloshing in lunar module during Apollo 14 flight and resultant erroneous indication of low level of propellan
Electrodic processes of derivatives of 2,2,4,4-tetramethylpentane on stationary solid electrodes 1. : Cyclic voltammetry of 3-hydrazones of 2,2,4,4 - tetramethylpentane
Electrodic processes of 2,2,4,4-tetramethylpentane derivatives of stationary solid electrodes 2. : Voltammetry of 3,3' dibromo - 2,2,4,4 - tetramethylpentane in dmf
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