105,793 research outputs found
Explicit soliton-black hole correspondence for static configurations
We construct an explicit map that transforms static, generalized sine-Gordon
metrics to black hole type metrics. This, in particular, provides for a further
description of the Cadoni correspondence (which extends the
Gegenberg-Kunstatter correspondence) of soliton solutions and extremal black
hole solutions in 2D dilaton gravity.Comment: Submitted to Phys Rev D, 7 pages, no figure
Notes on the Biology of \u3ci\u3eMelanocanthon Nigricornis\u3c/i\u3e (Coleoptera: Scarabaeidae)
Melanocanthon nigricornis was observed to break up, bundle up, roll away, and bury pieces of the cap of a gill mushroom growing in sandy prairie in Wisconsin. These beetles were also found on a dead lizard and one was observed to roll and bury mammalian carrion. This is the first report of any species in Melanocanthon rolling and burying pieces of fungus and carrion
SU3 isoscalar factors
A summary of the properties of the Wigner Clebsch-Gordan coefficients and
isoscalar factors for the group SU3 in the SU2U1 decomposition is
presented. The outer degeneracy problem is discussed in detail with a proof of
a conjecture (Braunschweig's) which has been the basis of previous work on the
SU3 coupling coefficients. Recursion relations obeyed by the SU3 isoscalar
factors are produced, along with an algorithm which allows numerical
determination of the factors from the recursion relations. The algorithm
produces isoscalar factors which share all the symmetry properties under
permutation of states and conjugation which are familiar from the SU2 case. The
full set of symmetry properties for the SU3 Wigner-Clebsch-Gordan coefficients
and isoscalar factors are displayed.Comment: 20 pages, LaTeX (earlier version incomplete
A method for the analysis of the benefits and costs for aeronautical research and technology
A relatively simple, consistent, and reasonable methodology for performing cost-benefit analyses which can be used to guide, justify, and explain investments in aeronautical research and technology is presented. The elements of this methodology (labeled ABC-ART for the Analysis of the Benefits and Costs of Aeronautical Research and Technology) include estimation of aircraft markets; manufacturer costs and return on investment versus aircraft price; airline costs and return on investment versus aircraft price and passenger yield; and potential system benefits--fuel savings, cost savings, and noise reduction. The application of this methodology is explained using the introduction of an advanced turboprop powered transport aircraft in the medium range market in 1978 as an example
Monte Carlo direct view factor and generalized radiative heat transfer programs
Computer programs find the direct view factor from one surface segment to another using the Monte carlo technique, and the radioactive-transfer coefficients between surface segments. An advantage of the programs is the great generality of problems treatable and rapidity of solution from problem conception to receipt of results
Non-parametric Reconstruction of Cluster Mass Distribution from Strong Lensing: Modelling Abell 370
We describe a new non-parametric technique for reconstructing the mass
distribution in galaxy clusters with strong lensing, i.e., from multiple images
of background galaxies. The observed positions and redshifts of the images are
considered as rigid constraints and through the lens (ray-trace) equation they
provide us with linear constraint equations. These constraints confine the mass
distribution to some allowed region, which is then found by linear programming.
Within this allowed region we study in detail the mass distribution with
minimum mass-to-light variation; also some others, such as the smoothest mass
distribution. The method is applied to the extensively studied cluster Abell
370, which hosts a giant luminous arc and several other multiply imaged
background galaxies. Our mass maps are constrained by the observed positions
and redshifts (spectroscopic or model-inferred by previous authors) of the
giant arc and multiple image systems. The reconstructed maps obtained for \a370
reveal a detailed mass distribution, with substructure quite different from the
light distribution. The method predicts the bimodal nature of the cluster and
that the projected mass distribution is indeed elongated along the axis defined
by the two dominant cD galaxies. But the peaks in the mass distribution appear
to be offset from the centres of the cDs. We also present an estimate for the
total mass of the central region of the cluster. This is in good agreement with
previous mass determinations. The total mass of the central region is
M=(2.0-2.7) 10^14 Msun/h50, depending on the solution chosen.Comment: 14 pages(19 postscript figures), minor corrections, MNRAS in pres
Development and application of a local linearization algorithm for the integration of quaternion rate equations in real-time flight simulation problems
High angular rates encountered in real-time flight simulation problems may require a more stable and accurate integration method than the classical methods normally used. A study was made to develop a general local linearization procedure of integrating dynamic system equations when using a digital computer in real-time. The procedure is specifically applied to the integration of the quaternion rate equations. For this application, results are compared to a classical second-order method. The local linearization approach is shown to have desirable stability characteristics and gives significant improvement in accuracy over the classical second-order integration methods
Carrion Beetles (Coleoptera: Silphidae) of Wisconsin
The first comprehensive faunal survey of the carrion beetles (Coleoptera: Silphidae) of Wisconsin is presented. Six genera and 14 species are recorded from the state, including a new state record, Heterosilpha ramosa (Say). Nicrophorus americanus Olivier was not recovered during this study. An annotated checklist includes species-specific geographical and temporal distributions, remarks on foods and habitat, and counties of specimen collections for each species
Electron beam fluorescence measurements in the Boeing hypersonic shock tunnel
The Calspan electron beam fluorescence (EBF) measurement system is described along with the results of measurements made in hypersonic flow. Numerous self-emitting metallic species were identified, many of which may be associated with an aging/erosion process within the B30HST. Because there were only 16 tunnel runs, it was only possible to obtain spectral measurements over a limited range of wavelengths and time sampling periods. Many spectral features of the flow remain uninvestigated. Because flow self-emission is important to all optical diagnostic techniques, it is recommended that additional spectral studies by performed. The three electron beam-excited species that were identified are nitrogen, helium, and nitric oxide. The high metallic radiation background interfered with attempts to obtain the time-wise variation of N2 density and He radiation with the optical fiber/PMT channels. In the case of the N2 density measurements the result of interference was increased uncertainty. Unfortunately, the interference caused the time-wise He measurements to fail completely. It is recommended that the electron beam be modulated to provide discrimination against the background radiation in future N2 density measurements. Careful data reduction produced useful measurements of N2 vibrational temperature, even though the high background from metallic species significantly increased measurement uncertainty. Perhaps the recommended additional spectral studies would reveal N2(+) First Negative System band-pair regions having less background. Detection of the He arrival was easily accomplished with the spectrometer/array detector system. Because of this, it is recommended that this means of detecting He arrival be used in the future. With proper calibrations of the system an He number density could be obtained. Although the flow conditions were out of limits for the run in which the NO spectrum was recorded, the usefulness of the NO spectrum for determination of free-stream rotational temperature was demonstrated and should be exploited in future experiments. Indeed, based on the strong NO signals, it is recommended that lower resolution NO spectra be obtained to provide a measure of NO vibrational temperature in the same manner that the N2 temperature was obtained
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