4,117 research outputs found
Performance with and without inlet radial distortion of a transonic fan stage designed for reduced loading in the tip region
A transonic compressor stage designed for a reduced loading in the tip region of the rotor blades was tested with and without inlet radial distortion. The rotor was 50 cm in diameter and designed for an operating tip speed of 420 m/sec. Although the rotor blade loading in the tip region was reduced to provide additional operating range, analysis of the data indicates that the flow around the damper appears to be critical and limited the stable operating range of this stage. For all levels of tip and hub radial distortion, there was a large reduction in the rotor stall margin
Performance and boundary-layer evaluation of a sonic inlet
Tests were conducted to determine the boundary layer characteristics and aerodynamic performance of a radial vane sonic inlet with a length/diameter ratio of 1 for several vane configurations. The sonic inlet was designed with a slight wavy wall type of diffuser geometry, which permits operation at high inlet Mach numbers (sufficiently high for good noise suppression) without boundary layer flow separation and with good total pressure recovery. A new method for evaluating the turbulent boundary layer was developed to separate the boundary layer from the inviscid core flow, which is characterized by a total pressure variation from hub to tip, and to determine the experimental boundary layer parameters
First principles theory of fluctuations in vortex liquids and solids
Consistent perturbation theory for thermodynamical quantities in type II
superconductors in magnetic field at low temperatures is developed. It is
complementary to the existing expansion valid at high temperatures.
Magnetization and specific heat are calculated to two loop order and compare
well to existing Monte Carlo simulations and experiments.Comment: 3 .ps fig. In press Phys. Rev.
Nanoscale spatially resolved infrared spectra from single microdroplets
Droplet microfluidics has emerged as a powerful platform allowing a large
number of individual reactions to be carried out in spatially distinct
microcompartments. Due to their small size, however, the spectroscopic
characterisation of species encapsulated in such systems remains challenging.
In this paper, we demonstrate the acquisition of infrared spectra from single
microdroplets containing aggregation-prone proteins. To this effect, droplets
are generated in a microfluidic flow-focussing device and subsequently
deposited in a square array onto a ZnSe prism using a micro stamp. After
drying, the solutes present in the droplets are illuminated locally by an
infrared laser through the prism, and their thermal expansion upon absorption
of infrared radiation is measured with an atomic force microscopy tip, granting
nanoscale resolution. Using this approach, we resolve structural differences in
the amide bands of the spectra of monomeric and aggregated lysozyme from single
microdroplets with picolitre volume.Comment: 5 pages, 3 Figure
The prevention of malnutrition in a person with the disease cancer: application of a format verification, model of nutritional-metabolic according to Functional Gordon, with NANDA-I NOC and NIC
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Developmental changes in children’s training strategies
Effective practice is key to learning. Yet, it is unclear whether
young children have the ability to make effective and adaptive
training choices. In this project, we investigated 4- to 7-year-old
children’s (n=146) ability to tailor their training strategies
to optimize performance outcomes. Children were presented
with one easy and one difficult guessing game and were asked
to choose which game they wanted to practice. Crucially, before
they chose, they were told that they would eventually be
tested either on the game of their choice (Choice condition) or
on the game the computer would randomly pick (Random condition).
Contrary to our hypotheses, we found that condition
per se did not predict children’s training choices. However, we
found that older children were more likely to make effective
and adaptive training choices than younger children. Overall,
our results indicate that children’s training choices improve
from ages 4 to 7 and inform the development of interventions
to support strategic learning
Divergence-type 2+1 dissipative hydrodynamics applied to heavy-ion collisions
We apply divergence-type theory (DTT) dissipative hydrodynamics to study the
2+1 space-time evolution of the fireball created in Au+Au relativistic
heavy-ion collisions at 200 GeV. DTTs are exact hydrodynamic
theories that do no rely on velocity gradient expansions and therefore go
beyond second-order theories. We numerically solve the equations of motion of
the DTT for Glauber initial conditions and compare the results with those of
second-order theory based on conformal invariants (BRSS) and with data. We find
that the charged-hadron minumum-bias elliptic flow reaches its maximum value at
lower in the DTT, and that the DTT allows for a value of
slightly larger than that of the BRSS. Our results show that the differences
between viscous hydrodynamic formalisms are a significant source of uncertainty
in the precise extraction of from experiments.Comment: v4: 29 pages, 12 figures, minor changes. Final version as published
in Phys. Rev.
Why the lowest Landau level approximation works in strongly type II superconductors
Higher than the lowest Landau level contributions to magnetization and
specific heat of superconductors are calculated using Ginzburg - Landau
equations approach. Corrections to the excitation spectrum around solution of
these equations (treated perturbatively) are found. Due to symmetries of the
problem leading to numerous cancellations the range of validity of the LLL
approximation in mean field is much wider then a naive range and extends all
the way down to . Moreover the contribution of higher
Landau levels is significantly smaller compared to LLL than expected naively.
We show that like the LLL part the lattice excitation spectrum at small
quasimomenta is softer than that of usual acoustic phonons. This enhanses the
effect of fluctuations. The mean field calculation extends to third order,
while the fluctuation contribution due to HLL is to one loop. This complements
the earlier calculation of the LLL part to two loop order.Comment: 20 pages, Latex file, three figure
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