626,495 research outputs found
Results from the EPL monkey-pod experiment conducted as part of the 1974 NASA/Ames shuttle CVT-2
The participation of the Environmental Physiology Laboratory (EPL) in the general purpose laboratory concept verification test 3 is documented. The EPL Monkey-Pod Experiment was designed to incorporate a 10-12 kg, pig tailed monkey, Macaca nemestrina, into the pod and measure the physiological responses of the animal continuously. Four major elements comprise the EPL Monkey-Pod Experiment System: (1) a fiberglass pod containing the instrumented monkey plus feeder and watering devices, (2) an inner console containing the SKYLAB mass spectrometer with its associated valving and electronic controls, sensing, control and monitoring units for lower body negative pressure, feeder activity, waterer activity, temperatures, and gas metabolism calibration, (3) an umbilical complex comprising gas flow lines and electrical cabling between the inner and outer console and (4) an outer console in principle representing the experiment support to be provided from general spacecraft sources
Bosonization of One-Dimensional Exclusons and Characterization of Luttinger Liquids
We achieve a bosonization of one-dimensional ideal gas of exclusion
statistics at low temperatures, resulting in a new variant of
conformal field theory with compactified radius . These
ideal excluson gases exactly reproduce the low- critical properties of
Luttinger liquids, so they can be used to characterize the fixed points of the
latter. Generalized ideal gases with mutual statistics and non-ideal gases with
Luttinger-type interactions have also similar behavior, controlled by an
effective statistics varying in a fixed-point line.Comment: 13 pages, revte
Results from the EPL monkey-pod experiment conducted as part of the 1974 NASA-Ames CVT/GPL 3
For abstract, see vol. 2
Adjustable spin torque in magnetic tunnel junctions with two fixed layers
We have fabricated nanoscale magnetic tunnel junctions (MTJs) with an
additional fixed magnetic layer added above the magnetic free layer of a
standard MTJ structure. This acts as a second source of spin-polarized
electrons that, depending on the relative alignment of the two fixed layers,
either augments or diminishes the net spin-torque exerted on the free layer.
The compound structure allows a quantitative comparison of spin-torque from
tunneling electrons and from electrons passing through metallic spacer layers,
as well as analysis of Joule selfheating effects. This has significance for
current-switched magnetic random access memory (MRAM), where spin torque is
exploited, and for magnetic sensing, where spin torque is detrimental.Comment: 3 pages, 2 figures, to appear in Appl. Phys. Let
Interannual sea-air CO2 flux variability from an observation-driven ocean mixed-layer scheme
Interannual anomalies in the sea–air carbon dioxide (CO2) exchange have been estimated from surface-ocean CO2 partial pressure measurements. Available data are sufficient to constrain these anomalies in large parts of the tropical and North Pacific and in the North Atlantic, in some areas covering the period from the mid 1980s to 2011. Global interannual variability is estimated as about 0.31 Pg Cyr−1 (temporal standard deviation 1993–2008). The tropical Pacific accounts for a large fraction of this global variability, closely tied to El Niño–Southern Oscillation (ENSO). Anomalies occur more than 6 months later in the east than in the west. The estimated amplitude and ENSO response are roughly consistent with independent information from atmospheric oxygen data. This both supports the variability estimated from surface-ocean carbon data and demonstrates the potential of the atmospheric oxygen signal to constrain ocean biogeochemical processes. The ocean variability estimated from surface-ocean carbon data can be used to improve land CO2 flux estimates from atmospheric inversions
Evidence for a superfluid density in t--J ladders
Applying three independent techniques, we give numerical evidence for a
finite superfluid density in isotropic hole-doped t--J ladders: We show the
existence of anomalous flux quantization, emphasising the contrasting behaviour
to that found in the `Luttinger liquid' regime stabilised at low electron
densities; We consider the nature of the low-lying excitation modes, finding
the 1-D analog of the superconducting state; And using a density matrix
renormalization group approach, we find long range pairing correlations and
exponentially decaying spin-spin correlations.Comment: 4 pages, revtex, postscript figs included, submitted to PR
Luttinger liquid behavior in spin chains with a magnetic field
Antiferromagnetic Heisenberg spin chains in a sufficiently strong magnetic
field are Luttinger liquids, whose parameters depend on the actual
magnetization of the chain. Here we present precise numerical estimates of the
Luttinger liquid dressed charge , which determines the critical exponents,
by calculating the magnetization and quadrupole operator profiles for
and S=1 chains using the density matrix renormalization group method. Critical
amplitudes and the scattering length at the chain ends are also determined.
Although both systems are Luttinger liquids the characteristic parameters
differ considerably.Comment: Final version, 6 pages, 6 EPS figure
Provenance and geochemistry of exotic clasts in conglomerates of the Oligocene Torehina Formation, Coromandel Peninsula, New Zealand
Non-marine pebble to cobble conglomerates of the lower Torehina Formation (Oligocene) crop out along western Coromandel Peninsula and overlie, with strong angular discordance, continental-margin metasedimentary rocks (Manaia Hill Group) of Mesozoic (Late Jurassic to ?Early Cretaceous) age. The conglomerates contain provenance information that identifies a pre-Oligocene depositional history obscured by the unconformable juxtaposition of these Tertiary and Mesozoic strata. Most clasts in the lower Torehina Formation are visually similar to local bedrock lithologies, including metamorphosed sandstones and argillites, but are kaolinitic and contain more detrital and authigenic chert, quartz, and potash feldspar. Local derivation of these clasts seems unlikely. By comparing geochemical ratios with those defined for continental margin sandstones, and well characterised New Zealand tectonic terranes, we interpret the majority of clasts in the lower Torehina Formation to have been derived from a dissected orogen, with mixtures of felsic and volcanogenic-derived sediment. The most likely sources are the Waipapa and Torlesse Terranes. The remaining 20–30% of the clasts in the lower Torehina Formation were originally friable, are coarse grained, and appear to be lithologically exotic relative to known metamorphosed sandstones in basement terrane sources on North Island. Some clasts contain coal laminae and particles, and all contain detrital kaolinite as lithic fragments and matrix. Such characteristics imply a non-marine to marginal-marine source containing sediment derived from strongly weathered granite or granodiorite. Mechanical fragility implies a likely proximal, easily erodible source. We propose that this group of clasts was derived from an Upper Cretaceous sedimentary cover, either part of a locally developed basin fill or part of a once regionally extensive cover on North Island. Either case defines a more widely distributed Cretaceous source than found today
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