16,908 research outputs found
Transport properties of N2 gas at cryogenic temperatures
The viscosity and thermal conductivity of nitrogen gas for the temperature range 5 K - 135 K have been computed from the second Chapman-Enskog approximation. Quantum effects, which become appreciable at the lower temperatures, are included by utilizing collision integrals based on quantum theory. A Lennard-Jones (12-6) potential was assumed. The computations yield viscosities about 20 percent lower than those predicted for the high end of this temperature range by the method of corresponding states, but the agreement is excellent when the computed values are compared with existing experimental data
Circular 73
An assessment of Growth of Infrastructure
Booms have been a common element in the development of frontier areas in the 19th and 20th
centuries. Most commonly, the booms have been associated with resource development such as the
mineral booms of the western United States. Booms usually involve some type of dramatic short-
term change which has wide-ranging implications (Gilmore, 1976).
Since the arrival of the Russians in Alaska, six major booms have occurred: furs, whales,
salmon, minerals, military, and petroleum. Each of these booms has, to some degree, created changes
in the landscape of Alaska, in particular, the infrastructural base, which in turn has facilitated subsequent development, either another major boom, or a smaller development. For example, agricultural
development has been enhanced by mineral, military, and petroleum booms in Alaska. The cumulative impact on infrastructure of more than one boom, or multibooms, as it is referred to here, is the
focus of this paper.
One problem encountered in studying booms is that there is no general agreement on what
constitutes a boom. Detailed studies of booms in communities such as Dixon’s (1978) analysis of
Fairbanks and Gilmore’s multi-community work in the Great Plains—Rocky •mountain regions,
contained no specific definition of the term “boom”. Yet it was clear in each study that something
dramatic had occurred. More general historical studies of the Western mineral bonanzas (Greever,
1963) or the Klondike gold rush (Berton, 1958) likewise suggest a number of factors such as population rise, influx of money, resource extraction, and infrastructure expansion. But in each case, there
is no specific factor or define rate of something that specifically qualifies a time period as a boom. In
this study, we are concerned with dramatic change of events which have had a major impact on the
geographic landscape of an area, As a framework for the initial study, we review those events which
have been given attention as boom-type activities in the historical literature of Alaska (Rogers, 1962;
Naske and Slotnick, 1987)
Shuttle APS propellant thermal conditioner study
A study program was performed to allow selection of thermal conditioner assemblies for superheating O2 and H2 at supercritical pressures. The application was the auxiliary propulsion system (APS) for the space shuttle vehicle. The O2/H2 APS propellant feed system included propellant conditioners, of which the thermal conditioner assemblies were a part. Cryogens, pumped to pressures above critical, were directed to the thermal conditioner assembly included: (1) a gas generator assembly with ignition system and bipropellant valves, which burned superheated O2 and H2 at rich conditions; (2) a heat exchanger assembly for thermal conditioning of the cryogenic propellant; and (3) a dump nozzle for heat exchanger exhaust
Identifying Galaxy Mergers in Observations and Simulations with Deep Learning
Mergers are an important aspect of galaxy formation and evolution. We aim to
test whether deep learning techniques can be used to reproduce visual
classification of observations, physical classification of simulations and
highlight any differences between these two classifications. With one of the
main difficulties of merger studies being the lack of a truth sample, we can
use our method to test biases in visually identified merger catalogues. A
convolutional neural network architecture was developed and trained in two
ways: one with observations from SDSS and one with simulated galaxies from
EAGLE, processed to mimic the SDSS observations. The SDSS images were also
classified by the simulation trained network and the EAGLE images classified by
the observation trained network. The observationally trained network achieves
an accuracy of 91.5% while the simulation trained network achieves 65.2% on the
visually classified SDSS and physically classified EAGLE images respectively.
Classifying the SDSS images with the simulation trained network was less
successful, only achieving an accuracy of 64.6%, while classifying the EAGLE
images with the observation network was very poor, achieving an accuracy of
only 53.0% with preferential assignment to the non-merger classification. This
suggests that most of the simulated mergers do not have conspicuous merger
features and visually identified merger catalogues from observations are
incomplete and biased towards certain merger types. The networks trained and
tested with the same data perform the best, with observations performing better
than simulations, a result of the observational sample being biased towards
conspicuous mergers. Classifying SDSS observations with the simulation trained
network has proven to work, providing tantalizing prospects for using
simulation trained networks for galaxy identification in large surveys.Comment: Submitted to A&A, revised after first referee report. 20 pages, 22
figures, 14 tables, 1 appendi
Misc. Pub. 92-3
Entrance to the Chena Hot Springs Road is only 5 miles from
downtown Fairbanks. The road provides an excellent opportunity
to see an example o f the diversity of agricultural
production in the Tanana Valley
Detection and quantification of inverse spin Hall effect from spin pumping in permalloy/normal metal bilayers
Spin pumping is a mechanism that generates spin currents from ferromagnetic
resonance (FMR) over macroscopic interfacial areas, thereby enabling sensitive
detection of the inverse spin Hall effect that transforms spin into charge
currents in non-magnetic conductors. Here we study the spin-pumping-induced
voltages due to the inverse spin Hall effect in permalloy/normal metal bilayers
integrated into coplanar waveguides for different normal metals and as a
function of angle of the applied magnetic field direction, as well as microwave
frequency and power. We find good agreement between experimental data and a
theoretical model that includes contributions from anisotropic
magnetoresistance (AMR) and inverse spin Hall effect (ISHE). The analysis
provides consistent results over a wide range of experimental conditions as
long as the precise magnetization trajectory is taken into account. The spin
Hall angles for Pt, Pd, Au and Mo were determined with high precision to be
, , and ,
respectively.Comment: 11 page
Key dating features for timber-framed dwellings in Surrey
This article is made available through the Brunel Open Access Publishing Fund. Copyright @ The Vernacular Architecture Group 2013. MORE OpenChoice articles are open access and distributed under the terms of the Creative Commons Attribution License 3.0.The main component of the Surrey Dendrochronology Project is the accurate dating of 177 ‘dwellings’, nearly all by tree-ring analysis. The dates are used to establish date ranges for 52 ‘key features’, which cover many aspects of timber-framing from building type to details of carpentry. It is shown that changes of method and fashion were in many cases surprisingly rapid, almost abrupt in historical terms. Previous dating criteria for timber-framed dwellings in the county have been refined and new criteria introduced. Clusters of change from the 1440s and the 1540s are shown and some possible historical links suggested.The Heritage Lottery Fund, the Domestic Buildings Research Group (Surrey), the Surrey Archaeological Society and the historical societies of Charlwood, Farnham and Nutfield
Is more always better? An exploration of the differential effects of functional integration on performance in new product development
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