77,753 research outputs found
Aircraft energy efficiency laminar flow control glove flight conceptual design study
A laminar flow control glove applied to the wing of a short to medium range jet transport with aft mounted engines was designed. A slotted aluminum glove concept and a woven stainless steel mesh porous glove concept suction surfaces were studied. The laminar flow control glove and a dummy glove with a modified supercritical airfoil, ducting, modified wing leading and trailing edges, modified flaps, and an LFC trim tab were applied to the wing after slot spacing suction parameters, and compression power were determined. The results show that a laminar flow control glove can be applied to the wing of a jet transport with an appropriate suction system installed
Labour's record on financial regulation
In 1997 the new Labour government launched major initiatives in the area of financial regulation, setting up the Financial Services Authority as a comprehensive regulatory body, supported by the legislative framework of the Financial Services and Markets Act 2000. We evaluate the Labour government’s record on financial regulation in terms of its achievements and failures, especially in dealing with the global financial crisis that started in 2007. While we identify some clear flaws in regulatory design and enforcement, our evaluation highlights some inherent difficulties of financial regulation
Structural, vibrational and thermal properties of densified silicates : insights from Molecular Dynamics
Structural, vibrational and thermal properties of densified sodium silicate
(NS2) are investigated with classical molecular dynamics simulations of the
glass and the liquid state. A systematic investigation of the glass structure
with respect to density was performed. We observe a repolymerization of the
network manifested by a transition from a tetrahedral to an octahedral silicon
environment, the decrease of the amount of non-bridging oxygen atoms and the
appearance of three-fold coordinated oxygen atoms (triclusters). Anomalous
changes in the medium range order are observed, the first sharp diffraction
peak showing a minimum of its full-width at half maximum according to density.
The previously reported vibrational trends in densified glasses are observed,
such as the shift of the Boson peak intensity to higher frequencies and the
decrease of its intensity. Finally, we show that the thermal behavior of the
liquid can be reproduced by the Birch-Murnaghan equation of states, thus
allowing us to compute the isothermal compressibility
Biological effects of prolonged expoure of small animals to unusual gaseous environments semiannual report, 1 sep. 1964 - 28 feb. 1965
Biological effect of prolonged exposure of man and small animals to pure oxygen and helium - oxygen environmen
On the complexion of pseudoscalar mesons
A strongly momentum-dependent dressed-quark mass function is basic to QCD. It
is central to the appearance of a constituent-quark mass-scale and an
existential prerequisite for Goldstone modes. Dyson-Schwinger equation (DSEs)
studies have long emphasised this importance, and have proved that QCD's
Goldstone modes are the only pseudoscalar mesons to possess a nonzero leptonic
decay constant in the chiral limit when chiral symmetry is dynamically broken,
while the decay constants of their radial excitations vanish. Such features are
readily illustrated using a rainbow-ladder truncation of the DSEs. In this
connection we find (in GeV): f_{eta_c(1S)}= 0.233, m_{eta_c(2S)}=3.42; and
support for interpreting eta(1295), eta(1470) as the first radial excitations
of eta(548), eta'(958), respectively, and K(1460) as the first radial
excitation of the kaon. Moreover, such radial excitations have electromagnetic
diameters greater than 2fm. This exceeds the spatial length of lattices used
typically in contemporary lattice-QCD.Comment: 7 pages, 2 figures. Contribution to the proceedings of the "10th
International Symposium on Meson-Nucleon Physics and the Structure of the
Nucleon (MENU04)," IHEP, Beijing, China, 30/Aug.-4/Sept./0
COLA with massive neutrinos
The effect of massive neutrinos on the growth of cold dark matter
perturbations acts as a scale-dependent Newton's constant and leads to
scale-dependent growth factors just as we often find in models of gravity
beyond General Relativity. We show how to compute growth factors for
CDM and general modified gravity cosmologies combined with massive
neutrinos in Lagrangian perturbation theory for use in COLA and extensions
thereof. We implement this together with the grid-based massive neutrino method
of Brandbyge and Hannestad in and compare COLA simulations
to full -body simulations of CDM and gravity with
massive neutrinos. Our implementation is computationally cheap if the
underlying cosmology already has scale-dependent growth factors and it is shown
to be able to produce results that match -body to percent level accuracy
for both the total and CDM matter power-spectra up to Mpc.Comment: 29 pages, 15 figures, 1 table, version accepted for publication in
JCAP, added frame-lagging terms in 2LPT sections (results unaffected) and
appendix on comparison to SP
A Statistical Analysis of the Influence of Deep Convection on Water Vapor Variability in the Tropical Upper Troposphere
The factors that control the influence of deep convective detrainment on water vapor in the tropical upper troposphere are examined using observations from multiple satellites in conjunction with a trajectory model. Deep convection is confirmed to act primarily as a moisture source to the upper troposphere, modulated by the ambient relative humidity (RH). Convective detrainment provides strong moistening at low RH and offsets drying due to subsidence across a wide range of RH. Strong day-to-day moistening and drying takes place most frequently in relatively dry transition zones, where between 0.01% and 0.1% of Tropical Rainfall Measuring Mission Precipitation Radar observations indicate active convection. Many of these strong moistening events in the tropics can be directly attributed to detrainment from recent tropical convection, while others in the subtropics appear to be related to stratosphere-troposphere exchange. The temporal and spatial limits of the convective source are estimated to be about 36-48 h and 600-1500 km, respectively, consistent with the lifetimes of detrainment cirrus clouds. Larger amounts of detrained ice are associated with enhanced upper tropospheric moistening in both absolute and relative terms. In particular, an increase in ice water content of approximately 400% corresponds to a 10-90% increase in the likelihood of moistening and a 30-50% increase in the magnitude of moistening.NASA Global Energy and Water Cycle programNASA Earth System Science researchTerraACRIMSAT NNG04GK90GGeological Science
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