302 research outputs found
Measurement of interstage fluid-annulus dynamical properties
The work described in this paper is part of an Electric Power Research Institute sponsored effort to improve rotor vibrational performance on power plant feed water pumps. A major objective of this effort is to reduce vibration levels by devising inter-stage sealing configurations with optimized damping capacity, realizing that the typical multi-stage centrifugal pump has several ore inter-stage fluid annuli than it has journal bearings. Also, the fluid annuli are distributed between the journal bearings where vibration levels are highest and can therefore be 'exercised' more as dampers than can the bearings. Described in this paper is a test apparatus which has been built to experimentally determine fluid-annulus dynamical coefficients for various configurations of inter-stage sealing geometry
Hand’s Asymmetries in Fine Motor Precision and Speed Performance in Different Age Groups
Rose (1970) showed that women had more symmetrical precision in movements in hands, whereas men performed more asymmetrically (with dominance for right hand). These findings were congruent with Ananiev’s (1968) scheme differentiated for sexes, in which for men there was a need for use of additional adaptive mechanisms (asymmetry) whereas women passed with basic ones (symmetry). Our study aimedto check the hands symmetry/asymmetry and correlations in fine motor precision and speed in both sexes and how they change in different age groups. The results of our study showed that the highest asymmetry in fine motor precision was related (for both sex groups and among all movement types) to the developmental periodof life (12-17 years old) followed by group age of 64-95 due to ageing processes. In our study women performed with less asymmetry between both hands for majority of observable variables compared to men in all age groups. The highest frequency of asymmetrical performance in fine motor precision for both sexes was observed in the Frontal movement type, followed by the Transversal, and least, in the Sagittal. For the speed performance, the highest frequency of asymmetrical performance was shown in the Transversal movement type.
Keywords: fine motor precision; speed; sex differences; age-depended differences; Proprioceptive diagnostics; M.K.P
A statistical method for the identification of stars enriched in neutron-capture elements from medium-resolution spectra
We present an automated statistical method that uses medium-resolution
spectroscopic observations of a set of stars to select those that show evidence
of possessing significant amounts of neutron-capture elements. Our tool was
tested against a sample of F- and G-type stars distributed among
plates from the Galactic Understanding and Exploration (SEGUE) survey,
including that were directed at stellar Galaxy clusters. Focusing on five
spectral lines of europium in the visible window, our procedure ranked the
stars by their likelihood of having enhanced content of this atomic species and
identifies the objects that exhibit signs of being rich in neutron-capture
elements as those scoring in the upper . We find that several of the
cluster plates contain relatively large numbers of stars with significant
absorption around at least three of the five selected lines. The most prominent
is the globular cluster M3, where we measured a fraction of stars that are
potentially rich in heavy nuclides, representing at least .Comment: 7 pages, 2 figures, accepted for publication in Astronomy &
Astrophysics (v2
Intrinsic and observed dual AGN fractions from major mergers
A suite of 432 collisionless simulations of bound pairs of spiral galaxies
with mass ratios 1:1 and 3:1, and global properties consistent with the
CDM paradigm, is used to test the conjecture that major mergers fuel
the dual AGN (DAGN) of the local volume. Our analysis is based on the premise
that the essential aspects of this scenario can be captured by replacing the
physics of the central BH with restrictions on their relative separation in
phase space. We introduce several estimates of the DAGN fraction and infer
predictions for the activity levels and resolution limits usually involved in
surveys of these systems, assessing their dependence on the parameters
controlling the length of both mergers and nuclear activity. Given a set of
constraints, we find that the values adopted for some of the latter factors
often condition the outcomes from individual experiments. Still, the results do
not reveal, in general, very tight correlations, being the tendency of the
frequencies normalized to the merger time to anticorrelate with the orbital
circularity the clearest effect. In agreement with other theoretical studies,
our simulations predict intrinsic abundances of these systems that range from
few to depending on the maximum level of nuclear activity
achieved. At the same time, we show that these probabilities are reduced by
about an order of magnitude when they are filtered with the typical constraints
applied by observational studies of the DAGN fraction at low redshift. As a
whole, the results of the present work prove that the consideration of the most
common limitations involved in the detection of close active pairs at optical
wavelengths is sufficient by itself to reconcile the intrinsic frequencies
envisaged in a hierarchical universe with the small fractions of double-peaked
narrow-line systems which are often reported at kpc-scales.Comment: 24 pages, 11 figures, 3 Tables, accepted by A&
Human Herpesvirus 8 in Healthy Blood Donors, Argentina
Fil: Pérez, Celeste L. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Virología. Servicio Cultivo de Tejidos; Argentina.Fil: Tous, Mónica I. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas; Argentina.Fil: Zala, Norma. Hospital de Enfermedades Infecciosas “Francisco J Muñiz,”; Argentina.Fil: Camino, Sofia. Hospital de Enfermedades Infecciosas “Francisco J Muñiz,”; Argentina
Nickel Silicide Formation Using Excimer Laser Annealing
AbstractIn this work, we report on a self-aligned nickel silicide formation technique based on excimer laser annealing (ELA). We evaluate this process for the front contact formation of industrial PERC type solar cells on random pyramid textured Si surfaces where damage to surface texture, emitter passivation, or to the shallow junction should be avoided or minimized. PERC type solar cells obtained by POCl3 diffusion were processed on large area (12.5x12.5cm2) CZ-Si. Self-aligned litho-free Ni/Cu contacts defined by ps-laser ablation of the SiO2/SiNx anti-reflective coating (ARC) and subsequent ELA of the Ni layer were compared to conventional Ag screen printed contacts.The novel ELA process results in an absolute gain in Jsc of 0.8mA/cm2 as well as a drop of 0.3Ω.cm2 in series resistance (Rs) compared to SP Ag contacts due to reduced shading and resistance losses. This leads to 0.5% absolute increase in efficiency from 19.3% to 19.7% since other characteristics (Voc, pFF) could be maintained to the same level. In this work, the best performing cell with the ELA process reached an outstanding 20.0% energy conversion efficiency with Jsc=39.3mA/cm2, Voc=649.8mV, and FF=78.3%
SP-0489: HPV-transformation in the cervix and at non-cervical sites
Pla general d'un dels panells horitzontals sobre espais verds de Barcelona a l'exposició Ciutat. Barcelona projecta a l'Edifici Fòrum. Exposició sobre la planificació urbanística i arquitectònica de Barcelon
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