2,599 research outputs found
Measurements of temperature and pressure fluctuations in the T prime 2 cryogenic wind tunnel
Cold wire measurement of temperature fluctuations were made in a DERAT T'2 induction powered cryogenic wind tunnel for 2 types of liquid nitrogen injectors. Thermal turbulence measured in the tranquilization chamber depends to a great extent on the injector used; for fine spray of nitrogen drops, this level of turbulence seemed completely acceptable. Fluctuations in static pressure taken from the walls of the vein by Kulite sensors showed that there was no increase in aerodynamic noise during cryogenic gusts
Qualification of the T2 wind tunnel in cryogenic operation. B: Flow fluctuations, particle detection and qualification
This report presents part of the tests for verification of the T2 transonic induction wind tunnel in cryogenic operation. The first part of the results presented concerns fluctuations in pressure and temperature at ambient temperature and in cryogenic regulation. The second part presents the condensation phenomena which could be observed in the cryogenic flow by means of an optical particle detection system in the test section
Iterative adaption of the bidimensional wall of the French T2 wind tunnel around a C5 axisymmetrical model: Infinite variation of the Mach number at zero incidence and a test at increased incidence
The top and bottom two-dimensional walls of the T2 wind tunnel are adapted through an iterative process. The adaptation calculation takes into account the flow three-dimensionally. This method makes it possible to start with any shape of walls. The tests were performed with a C5 axisymmetric model at ambient temperature. Comparisons are made with the results of a true three-dimensional adaptation
Effect of the dynamic topology on the performance of PSO-2S algorithm for continuous optimization
International audiencePSO-2S is a multi-swarm PSO algorithm using charged particles in a partitioned search space for continuous optimization problems. In order to improve the performance of PSO-2S, this paper proposes a novel variant of this algorithm, called DPSO-2S, which uses the Dcluster neighborhood topologies to organize the communication networks between the particles. Experiments were conducted on a set of classical benchmark functions. The obtained results prove the effectiveness of the proposed algorithm
End-stage Renal Disease and Economic Incentives: The International Study of Health Care Organization and Financing
End-stage renal disease (ESRD), or kidney failure, is a debilitating, costly, and increasingly common medical condition. Little is known about how different financing approaches affect ESRD outcomes and delivery of care. This paper presents results from a comparative review of 12 countries with alternative models of incentives and benefits, collected under the International Study of Health Care Organization and Financing, a substudy within the Dialysis Outcomes and Practice Patterns Study. Variation in spending per ESRD patient is relatively small and is correlated with overall per capita health care spending. Between-country variations in spending are reduced using an input price parity index constructed for this study. Remaining differences in costs and outcomes do not seem strongly linked to differences in incentives embedded in national programs.
Stability of Relativistic Matter with Magnetic Fields for Nuclear Charges up to the Critical Value
We give a proof of stability of relativistic matter with magnetic fields all
the way up to the critical value of the nuclear charge .Comment: LaTeX2e, 12 page
The Konkoly Blazhko Survey: Is light-curve modulation a common property of RRab stars?
A systematic survey to establish the true incidence rate of the Blazhko
modulation among short-period, fundamental-mode, Galactic field RR Lyrae stars
has been accomplished. The Konkoly Blazhko Survey (KBS) was initiated in 2004.
Since then more than 750 nights of observation have been devoted to this
project. A sample of 30 RRab stars was extensively observed, and light-curve
modulation was detected in 14 cases. The 47% occurrence rate of the modulation
is much larger than any previous estimate. The significant increase of the
detected incidence rate is mostly due to the discovery of small-amplitude
modulation. Half of the Blazhko variables in our sample show modulation with so
small amplitude that definitely have been missed in the previous surveys. We
have found that the modulation can be very unstable in some cases, e.g. RY Com
showed regular modulation only during one part of the observations while during
two seasons it had stable light curve with abrupt, small changes in the
pulsation amplitude. This type of light-curve variability is also hard to
detect in other Survey's data. The larger frequency of the light-curve
modulation of RRab stars makes it even more important to find the still lacking
explanation of the Blazhko phenomenon. The validity of the [Fe/H](P,phi_{31})
relation using the mean light curves of Blazhko variables is checked in our
sample. We have found that the formula gives accurate result for
small-modulation-amplitude Blazhko stars, and this is also the case for
large-modulation-amplitude stars if the light curve has complete phase
coverage. However, if the data of large-modulation-amplitude Blazhko stars are
not extended enough (e.g. < 500 data points from < 15 nights), the formula may
give false result due to the distorted shape of the mean light curve used.Comment: Accepted for publication in MNRAS, 14 pages, 7 Figure
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