6,420 research outputs found
Effect of empennage arrangement on single-engine nozzle/afterbody static pressures at transonic speeds
An investigation has been conducted in the Langley 16-Foot Transonic Tunnel to determine the effects on empennage arrangement on single-engine nozzle/afterbody static pressures. Tests were done at Mach numbers from 0.60 to 1.20, nozzle pressure ratios from 1.0 (jet off) to 8.0. and angles of attack from -3 to 9 deg (at jet off conditions), depending on Mach number. Three empennage arrangements (aft, staggered, and forward) were investigated. Extensive measurements were made of static pressure on the nozzle/afterbody in the vicinity of the tail surfaces
Cellularity in polyhedra
AbstractA compact subset X of a polyhedron P is cellular in P if there is a pseudoisotropy of P shrinking precisely X to a point. A proper surjection between polyhedra f:P→Q is cellular if each point inverse of f is cellular in P. It is shown that if f:P→Q is a cellular map and either P or Q is a generalized n-manifold, n≠4, then f is approximable by homeomorphisms. Also, if P or Q is an n-manifold with boundary, n≠4, 5, then a cellular map f:P→Q is approximable by homeomorphisms. A cellularity criterion for a special class of cell-like sets in polyhedra is established
Economic Impacts of Aquatic Vegetation to Angling in Two South Carolina Reservoirs
Angler creel surveys and economic impact models were
used to evaluate potential expansion of aquatic vegetation in
Lakes Murray and Moultrie, South Carolina. (PDF contains 4 pages.
Density Functional Theory of Inhomogeneous Liquids: II. A Fundamental Measure Approach
Previously, it has been shown that the direct correlation function for a
Lennard-Jones fluid could be modeled by a sum of that for hard-spheres, a
mean-field tail and a simple linear correction in the core region constructed
so as to reproduce the (known) bulk equation of state of the fluid(Lutsko, JCP
127, 054701 (2007)). Here, this model is combined with ideas from Fundamental
Measure Theory to construct a density functional theory for the free energy.
The theory is shown to accurately describe a range of inhomogeneous conditions
including the liquid-vapor interface, the fluid in contact with a hard wall and
a fluid confined in a slit pore. The theory gives quantitatively accurate
predictions for the surface tension, including its dependence on the potential
cutoff. It also obeys two important exact conditions: that relating the direct
correlation function to the functional derivative of the free energy with
respect to density, and the wall theorem.Comment: to appear in J. Chem. Phy
The promise and peril of genomic screening in the general population
Utilization of sequencing to screen the general population for preventable monogenic conditions is receiving substantial attention due to its potential to decrease morbidity and mortality. However, the selection of which variants to return is a serious implementation challenge. Procedures must be investigated to ensure optimal test characteristics and avoidance of harm from false positive test results
Phase behavior of a confined nano-droplet in the grand-canonical ensemble: the reverse liquid-vapor transition
The equilibrium density distribution and thermodynamic properties of a
Lennard-Jones fluid confined to nano-sized spherical cavities at constant
chemical potential was determined using Monte Carlo simulations. The results
describe both a single cavity with semipermeable walls as well as a collection
of closed cavities formed at constant chemical potential. The results are
compared to calculations using classical Density Functional Theory (DFT). It is
found that the DFT calculations give a quantitatively accurate description of
the pressure and structure of the fluid. Both theory and simulation show the
presence of a ``reverse'' liquid-vapor transition whereby the equilibrium state
is a liquid at large volumes but becomes a vapor at small volumes.Comment: 13 pages, 8 figures, to appear in J. Phys. : Cond. Mat
TEDI: the TripleSpec Exoplanet Discovery Instrument
The TEDI (TripleSpec - Exoplanet Discovery Instrument) will be the first
instrument fielded specifically for finding low-mass stellar companions. The
instrument is a near infra-red interferometric spectrometer used as a radial
velocimeter. TEDI joins Externally Dispersed Interferometery (EDI) with an
efficient, medium-resolution, near IR (0.9 - 2.4 micron) echelle spectrometer,
TripleSpec, at the Palomar 200" telescope. We describe the instrument and its
radial velocimetry demonstration program to observe cool stars.Comment: 6 Pages, To Appear in SPIE Volume 6693, Techniques and
Instrumentation for Detection of Exoplanets II
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