22,896 research outputs found
Tracking in Antiproton Annihilation Experiments
A major ingredient of the planned new accelerator complex FAIR, to be
constructed at the GSI, Darmstadt, Germany, is the availability of antiproton
beams with high quality and intensity. Among the experiments which will make
use of this opportunity is PANDA, a dedicated experiment to study antiproton
annihilations on nucleons and nuclei. This article gives an overview on the
foreseen techniques to perform charged particle tracking in the high rate
environment of this experiment.Comment: 1 tar.gz file containing 5 pages paper, 3 figures in 5 files;
proceedings of the TIME05 worksho
The effect of circumferential distortion on fan performance at two levels of blade loading
Single stage fans designed for two levels of pressure ratio or blade loading were subjected to screen-induced circumferential distortions of 90-degree extent. Both fan rotors were designed for a blade tip speed of 425 m/sec, blade solidity of 1.3 and a hub-to-tip radius ratio of 0.5. Circumferential measurements of total pressure, temperature, static pressure, and flow angle were obtained at the hub, mean and tip radii at five axial stations. Rotor loading level did not appear to have a significant influence on rotor response to distorted flow. Losses in overall pressure ratio due to distortion were most severe in the stator hub region of the more highly loaded stage. At the near stall operating condition tip and hub regions of (either) rotor demonstrated different response characteristics to the distorted flow. No effect of loading was apparent on interactions between rotor and upstream distorted flow fields
A Theoretical and practical assessment of open source development and dissemination of construction IT solutions
A BeppoSAX observation of the supersoft source 1E 0035.4-7230
Results from a 37,000 s BeppoSAX Low-Energy Concentrator Spectrometer (LECS)
observation of the supersoft source SMC 13 (=1E 0035.4-7230) in the Small
Magellanic Cloud are reported. The BeppoSAX spectrum is fitted either with a
blackbody spectrum with an effective temperature kT = 26-58 eV, an LTE white
dwarf atmosphere spectrum with kT = 35-50 eV, or a non-LTE white dwarf
atmosphere spectrum with kT = 25-32 eV. The bolometric luminosity is < 8 10^37
erg s-1 and < 3 10^37 erg s^-1 for the LTE and the non-LTE spectrum. We also
applied a spectral fit to combined spectra obtained with BeppoSAX LECS and with
ROSAT PSPC. The kT derived for the non-LTE spectrum is 27-29 eV, the bolometric
luminosity is 1.1-1.2 10^37 erg s^-1. We can exclude any spectrally hard
component with a luminosity > 2 10^35 erg s^-1 (for a bremmstrahlung with a
temperature of 0.5 keV) at a distance of 60 kpc. The LTE temperature is
therefore in the range 5.5+/-0.2 10^5 K and the non-LTE temperature in the
range 3.25+/-0.16 10^5 K. Assuming the source is on the stability line for
atmospheric nuclear burning, we constrain the white dwarf mass from the LTE and
the non-LTE fit to ~1.1 M-solar and ~0.9 M-solar respectively. However, the
temperature and luminosity derived with the non-LTE model for 1E 0035.4-7230 is
consistent with a lower mass M~0.6-0.7 M-solar white dwarf as predicted by Sion
and Starrfield (1994). At the moment, neither of these two alternatives for the
white dwarf mass can be excluded.Comment: 6 pages, accepted by A&A March 30th 199
Interpolation and harmonic majorants in big Hardy-Orlicz spaces
Free interpolation in Hardy spaces is caracterized by the well-known Carleson
condition. The result extends to Hardy-Orlicz spaces contained in the scale of
classical Hardy spaces , . For the Smirnov and the Nevanlinna
classes, interpolating sequences have been characterized in a recent paper in
terms of the existence of harmonic majorants (quasi-bounded in the case of the
Smirnov class). Since the Smirnov class can be regarded as the union over all
Hardy-Orlicz spaces associated with a so-called strongly convex function, it is
natural to ask how the condition changes from the Carleson condition in
classical Hardy spaces to harmonic majorants in the Smirnov class. The aim of
this paper is to narrow down this gap from the Smirnov class to ``big''
Hardy-Orlicz spaces. More precisely, we characterize interpolating sequences
for a class of Hardy-Orlicz spaces that carry an algebraic structure and that
are strictly bigger than . It turns out that the
interpolating sequences are again characterized by the existence of
quasi-bounded majorants, but now the weights of the majorants have to be in
suitable Orlicz spaces. The existence of harmonic majorants in such Orlicz
spaces will also be discussed in the general situation. We finish the paper
with an example of a separated Blaschke sequence that is interpolating for
certain Hardy-Orlicz spaces without being interpolating for slightly smaller
ones.Comment: 19 pages, 2 figure
Luminous supersoft X-ray emission from the recurrent nova U Scorpii
BeppoSAX detected luminous 0.2-2.0 keV supersoft X-ray emission from the
recurrent nova U Sco ~19-20 days after the peak of the optical outburst in
February 1999. U Sco is the first recurrent nova to be observed during a
luminous supersoft X-ray phase. Non-LTE white dwarf atmosphere spectral models
(together with a ~0.5 keV optically thin thermal component) were fitted to the
BeppoSAX spectrum. We find that the fit is acceptable assuming enriched He and
an enhanced N/C ratio. This implies that the CNO cycle was active during the
outburst, in agreement with a thermonuclear runaway scenario. The best-fit
temperature is ~9 10^5 K and the bolometric luminosity those predicted for
steady nuclear burning on a WD close to the Chandrasekhar mass. The fact that
U~Sco was detected as a supersoft X-ray source is consistent with steady
nuclear burning continuing for at least one month after the outburst. This
means that only a fraction of the previously accreted H and He was ejected
during the outburst and that the WD can grow in mass, ultimately reaching the
Chandrasekhar limit. This makes U~Sco a candidate type Ia supernova progenitor.Comment: 4 pages, accepted by A&A Letters 15 June 199
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