4,744 research outputs found
Existence theorems in the geometrically non-linear 6-parametric theory of elastic plates
In this paper we show the existence of global minimizers for the
geometrically exact, non-linear equations of elastic plates, in the framework
of the general 6-parametric shell theory. A characteristic feature of this
model for shells is the appearance of two independent kinematic fields: the
translation vector field and the rotation tensor field (representing in total 6
independent scalar kinematic variables). For isotropic plates, we prove the
existence theorem by applying the direct methods of the calculus of variations.
Then, we generalize our existence result to the case of anisotropic plates. We
also present a detailed comparison with a previously established Cosserat plate
model.Comment: 19 pages, 1 figur
Simulation and Analysis Chain for Acoustic Ultra-high Energy Neutrino Detectors in Water
Acousticneutrinodetectionisapromisingapproachforlarge-scaleultra-highenergyneutrinodetectorsinwater.In
this article, a Monte Carlo simulation chain for acoustic neutrino detection
devices in water will be presented. The simulation chain covers the generation
of the acoustic pulse produced by a neutrino interaction and its propagation to
the sensors within the detector. Currently, ambient and transient noise models
for the Mediterranean Sea and simulations of the data acquisition hardware,
equivalent to the one used in ANTARES/AMADEUS, are implemented. A pre-selection
scheme for neutrino-like signals based on matched filtering is employed, as it
is used for on-line filtering. To simulate the whole processing chain for
experimental data, signal classification and acoustic source reconstruction
algorithms are integrated in an analysis chain. An overview of design and
capabilities of the simulation and analysis chain will be presented and
preliminary studies will be discussed.Comment: 6 pages, 5 figures, ARENA 2012. arXiv admin note: substantial text
overlap with arXiv:1304.057
Radio Emission Associated with Ultraluminous X-ray Sources in the Galaxy Merger NGC 3256
We present new 6, 3.6, and 2 cm VLA radio observations of the nearby merger
system NGC 3256, with resolutions of ~100 pc, which reveal compact radio
sources embedded in more diffuse emission at all three wavelengths. The two
radio nuclei are partially resolved, but the two dominant compact sources that
remain coincide with the two most powerful compact Ultraluminous X-ray sources
(ULXs) recently reported by Lira et al. The radio/X-ray ratios for these two
sources are too high by factors of >100-1000 to be normal X-ray binaries.
However, their radio and X-ray powers and ratios are consistent with
low-luminosity active galactic nuclei (LLAGNs), and optical emission lines
suggest the presence of a nuclear disk around the northern nucleus. If the two
nuclear ULXs are LLAGNs, their associated black holes are separated by only
\~1kpc, about 6 times closer to one another than those found recently in the
merger galaxy NGC 6240. A third ULX on the outskirts of the merger is also a
radio source, and probably is a collection of supernova remnants. The remaining
ULXs are not coincident with any source of compact radio emission, and are
consistent with expectations for beamed X-ray binaries or intermediate-mass
black holes.Comment: Accepted for ApJ (10 pages, 5 figures
Recommended from our members
Complete Genome Sequence of the Citrobacter freundii Type Strain.
Citrobacter freundii is a species of facultative anaerobic Gram-negative bacteria of the family Enterobacteriaceae The complete genome is composed of a single chromosomal circle of 4,957,773 bp with a G+C content of 52%
Evaluation of ozone difluoride as a liquid propellant additive Final report
Ozone difluoride evaluated as liquid propellant additiv
Spitzer Observations of Centaurus A: Infrared Synchrotron Emission from the Northern Lobe
We present measurements obtained with the Spitzer Space Telescope in five
bands from 3.6-24 microns of the northern inner radio lobe of Centaurus A, the
nearest powerful radio galaxy. We show that this emission is synchrotron in
origin. Comparison with ultraviolet observations from GALEX shows that diffuse
ultraviolet emission exists in a smaller region than the infrared but also
coincides with the radio jet. We discuss the possibility, that synchrotron
emission is responsible for the ultraviolet emission and conclude that further
data are required to confirm this.Comment: 4 pages, accepted by ApJ
Development of Combined Opto-Acoustical Sensor Modules
The faint fluxes of cosmic neutrinos expected at very high energies require
large instrumented detector volumes. The necessary volumes in combination with
a sufficient shielding against background constitute forbidding and complex
environments (e.g. the deep sea) as sites for neutrino telescopes. To withstand
these environments and to assure the data quality, the sensors have to be
reliable and their operation has to be as simple as possible. A compact sensor
module design including all necessary components for data acquisition and
module calibration would simplify the detector mechanics and ensures the long
term operability of the detector. The compact design discussed here combines
optical and acoustical sensors inside one module, therefore reducing
electronics and additional external instruments for calibration purposes. In
this design the acoustical sensor is primary used for acoustic positioning of
the module. The module may also be used for acoustic particle detection and
marine science if an appropriate acoustical sensor is chosen.
First tests of this design are promising concerning the task of calibration.
To expand the field of application also towards acoustic particle detection
further improvements concerning electromagnetic shielding and adaptation of the
single components are necessary.Comment: 4 pages, 2 figures, ARENA2010 proceeding
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