27,184 research outputs found
Installing fiber insulation
A method for installing fragile, high temperature insulation batting in an elongated cavity or in a resilient wire sleeve to form a resilient seal. The batting is preformed to rough dimensions and wrapped in a plastic film, the film being of a material which is fugitive at a high temperature. The film is heat sealed and trimmed to form a snugly fit skin which overlaps at least at one end to permit attachment of a pull cord. The film absorbs the tensile force of pulling the film enclosed batting through the cavity or wire mesh sleeve and is subsequently driven off by high temperature baking, leaving only the insulation in the cavity or wire mesh sleeve
N=2 Super-Yang-Mills Theory from a Chern-Simons Action
We present a Chern-Simons action for N=2 Super-Yang-Mills theory (SYM) in
'full' N=2 superspace (hyperspace) augmented by coordinates of the internal
SU(2) group and show that this action can be reduced to the usual SYM action in
the Harmonic hyperspace. We also discover that the 'choice' of Harmonic
hyperspace is not unique and under suitable conditions, further reduction to
the well-known Projective hyperspace is possible.Comment: 1+8+1 pages, 1 figur
Spectroscopy of the optical Einstein ring 0047-2808
We present optical and near-infrared spectroscopic observations of the
optical Einstein ring 0047-2808. We detect both [OIII] lines 4959, 5007 near
2.3 micron, confirming the redshift of the lensed source as z=3.595. The Ly-a
line is redshifted relative to the [OIII] line by 140+-20 km/s. Similar
velocity shifts have been seen in nearby starburst galaxies. The [OIII] line is
very narrow, 130 km/s FWHM. If the ring is the image of the centre of a galaxy
the one-dimensional stellar velocity dispersion sigma=55 km/s is considerably
smaller than the value predicted by Baugh et al. (1998) for the somewhat
brighter Lyman-break galaxies. The Ly-a line is significantly broader than the
[OIII] line, probably due to resonant scattering. The stellar central velocity
dispersion of the early-type deflector galaxy at z=0.485 is 250+-30 km/s. This
value is in good agreement both with the value predicted from the radius of the
Einstein ring (and a singular isothermal sphere model for the deflector), and
the value estimated from the D_n-sigma relation.Comment: 7 pages, 3 figures, accepted for publication in MNRA
Dynamic Relationships Among Selected U.S. Commodity-Based, Value Added Markets: Applying Directed Acyclic Graphs to a Time Series Model
This paper demonstrates the application of a recently developed methodology, the combination of directed acyclic graphs (DAGs) with Bernanke structural vector autoregression (VAR) models, to model a system of U.S. commodity-related and value-added markets. As an example, the paper applies this methodology to a quarterly system of U.S. markets: the wheat market and a set of downstream milling and bakery markets that use wheat as an input. Analyses of the model's impulse response simulations and forecast error variance decompositions provide updated estimates of market elasticity parameters that drive these markets, and updated policy-relevant information on how these quarterly markets run and dynamically interact. Results suggest that movements in commodity-based markets strongly influence each other, although most of these effects occur in the long run beyond a single crop cycle. The paper illuminates how important U.S. food prices respond to wheat farm market shocks in price and quantity.Bernanke structural VARs, directed acyclic graphs, quarterly wheat-related markets, Industrial Organization, Marketing, Research Methods/ Statistical Methods,
Linear electric field frequency shift (important for next generation electric dipole moment searches) induced in confined gases by a magnetic field gradient
The search for particle electric dipole moments (edm) represents a most
promising way to search for physics beyond the standard model. A number of
groups are planning a new generation of experiments using stored gases of
various kinds. In order to achieve the target sensitivities it will be
necessary to deal with the systematic error resulting from the interaction of
the well-known field with
magnetic field gradients (often referred to as the geometric phase effect
(Commins, ED; Am. J. Phys. \QTR{bf}{59}, 1077 (1991), Pendlebury, JM
\QTR{em}{et al;} Phys. Rev. \QTR{bf}{A70}, 032102 (2004)). This interaction
produces a frequency shift linear in the electric field, mimicking an edm. In
this work we introduce an analytic form for the velocity auto-correlation
function which determines the velocity-position correlation function which in
turn determines the behavior of the frequency shift (Lamoreaux, SK and Golub,
R; Phys. Rev \QTR{bf}{A71}, 032104 (2005)) and show how it depends on the
operating conditions of the experiment. We also discuss some additional issues.Comment: 21 pages, 5 figure
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