600 research outputs found
Hemodynamic design optimization of a ventricular cannula applying Computational Fluid Dynamics (CFD)
Nowadays, a Ventricular Assist Device (VAD) is a hope of clinic solution to patients with heart failure. This study presents the design of the "trumpet mouth" ventricular cannula (TMVC) connected to a pediatric VAD, optimized to reduce the conditions that generate blood damage. The flow through the TMVC is analysed using Computational Fluid Dynamics (CFD) techniques. The optimization of the TMVC considered the turbulent and byphasic nature of the flow at the systolic and diastolic phases of the cardiac cycle
La inclinacion española
Copia digital. Valladolid : Junta de Castilla y León. Consejería de Cultura y Turismo, 2009-2010Contiene, además: El conde las legumbres, del mismo auto
Convergence of vector bundles with metrics of Sasaki-type
If a sequence of Riemannian manifolds, , converges in the pointed
Gromov-Hausdorff sense to a limit space, , and if are vector
bundles over endowed with metrics of Sasaki-type with a uniform upper
bound on rank, then a subsequence of the converges in the pointed
Gromov-Hausdorff sense to a metric space, . The projection maps
converge to a limit submetry and the fibers converge to
its fibers; the latter may no longer be vector spaces but are homeomorphic to
, where is a closed subgroup of ---called the {\em wane
group}--- that depends on the basepoint and that is defined using the holonomy
groups on the vector bundles. The norms converges to a map
compatible with the re-scaling in and the -action
on converges to an action on compatible with the
limiting norm.
In the special case when the sequence of vector bundles has a uniform lower
bound on holonomy radius (as in a sequence of collapsing flat tori to a
circle), the limit fibers are vector spaces. Under the opposite extreme, e.g.
when a single compact -dimensional manifold is re-scaled to a point, the
limit fiber is where is the closure of the holonomy group of the
compact manifold considered.
An appropriate notion of parallelism is given to the limiting spaces by
considering curves whose length is unchanged under the projection. The class of
such curves is invariant under the -action and each such curve preserves
norms. The existence of parallel translation along rectifiable curves with
arbitrary initial conditions is also exhibited. Uniqueness is not true in
general, but a necessary condition is given in terms of the aforementioned wane
groups .Comment: 44 pages, 1 figure, in V.2 added Theorem E and Section 4 on
parallelism in the limit space
Sensitivity plots for WIMP modulation searches
Prospects of WIMP searches using the annual modulation signature are
discussed on statistical grounds, introducing sensitivity plots for the
WIMP-nucleon scalar cross section.Comment: 3 pages, 2 figures, talk given at TAUP'99, september 199
Sensitivity plots for WIMP direct detection using the annual modulation signature
Annual modulation due to the Earth's motion around the Sun is a well known
signature of the expected WIMP signal induced in a solid state underground
detector. In the present letter we discuss the prospects of this technique on
statistical grounds, introducing annual-modulation sensitivity plots for the
WIMP-nucleon scalar cross section for different materials and experimental
conditions. The highest sensitivity to modulation is found in the WIMP mass
interval 10 GeV< m_W < 130 GeV, the actual upper limit depending from the
choice of the astrophysical parameters, while the lowest values of the
explorable WIMP-nucleon elastic cross-sections fall in most cases within one
order of magnitude of the sensitivities of present direct detection WIMP
searches.Comment: 24 pages, ReVTeX, 9 figures, submitted to Astroparticle Physic
New constraints on WIMPs from the Canfranc IGEX dark matter search
The IGEX Collaboration enriched 76Ge double-beta decay detectors are
currently operating in the Canfranc Underground Laboratory with an overburden
of 2450 m.w.e. A recent upgrade has made it possible to use them in a search
for WIMPs. A new exclusion plot has been derived for WIMP-nucleon
spin-independent interaction. To obtain this result, 30 days of data from one
IGEX detector, which has an energy threshold of ~4 keV, have been considered.
These data improve the exclusion limits derived from other germanium diode
experiments in the ~50 GeV DAMA region, and show that with a moderate
improvement of the background below 10 keV, the DAMA region may be tested with
an additional 1 kg-year of exposure.Comment: 7 pages, 2 figures, submitted to Physics Letter
Pulse Shape Discrimination in the IGEX Experiment
The IGEX experiment has been operating enriched germanium detectors in the
Canfranc Underground Laboratory (Spain) in a search for the neutrinoless double
decay of 76Ge. The implementation of Pulse Shape Discrimination techniques to
reduce the radioactive background is described in detail. This analysis has
been applied to a fraction of the IGEX data, leading to a rejection of ~60 % of
their background, in the region of interest (from 2 to 2.5 MeV), down to ~0.09
c/(keV kg y).Comment: 18 pages, 10 figure
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