16,051 research outputs found
The optimization air separation plants for combined cycle MHD-power plant applications
Some of the design approaches being employed during a current supported study directed at developing an improved air separation process for the production of oxygen enriched air for magnetohydrodynamics (MHD) combustion are outlined. The ultimate objective is to arrive at conceptual designs of air separation plants, optimized for minimum specific power consumption and capital investment costs, for integration with MHD combined cycle power plants
Solar-radiation-induced damage to optical properties of ZnO-type pigments Technical summary report, Jul. 1966 - Feb. 1968
Mechanisms of solar radiation damage to optical properties in zinc oxide pigments in visible and infrared region
Rural Competitiveness: Results of the 1996 Rural Manufacturing Survey
Establishments in metropolitan and nonmetropolitan locations are surprisingly similar in their adoption of new technologies, worker skill requirements, use of government programs and technical assistance, exports, and sources of financing, according to the results of a nationwide survey of 3,909 manufacturing businesses. The most widespread concern of both metro and nonmetro businesses appears to be with quality of labor. Survey respondents report rapidly increasing skill requirements, and many report problems finding qualified workers. Quality of local labor is the most frequently cited problem associated with nonmetro business locations. Access to credit, transportation, and telecommunications infrastructure is a problem of secondary importance for both metro and nonmetro respondents. Rural communities face a considerable challenge in supplying workers with needed skills. The fastest-growing skill requirements -- computer, interpersonal/teamwork, and problem-solving skills -- are not central to traditional academic instruction.rural manufacturing, sample survey, worker skills, manufacturing location, credit availability, technology adoption, Community/Rural/Urban Development,
Superfield Realizations of Lorentz and CPT Violation
Superfield realizations of Lorentz-violating extensions of the Wess-Zumino
model are presented. These models retain supersymmetry but include terms that
explicitly break the Lorentz symmetry. The models can be understood as arising
from superspace transformations that are modifications of the familiar one in
the Lorentz-symmetric case.Comment: 10 page
Yarkovsky Drift Detections for 247 Near-Earth Asteroids
The Yarkovsky effect is a thermal process acting upon the orbits of small
celestial bodies, which can cause these orbits to slowly expand or contract
with time. The effect is subtle (da/dt ~ 10^-4 au/My for a 1 km diameter
object) and is thus generally difficult to measure. We analyzed both optical
and radar astrometry for 600 near-Earth asteroids (NEAs) for the purpose of
detecting and quantifying the Yarkovsky effect. We present 247 NEAs with
measured drift rates, which is the largest published set of Yarkovsky
detections. This large sample size provides an opportunity to examine the
Yarkovsky effect in a statistical manner. In particular, we describe two
independent population-based tests that verify the measurement of Yarkovsky
orbital drift. First, we provide observational confirmation for the Yarkovsky
effect's theoretical size dependence of 1/D, where D is diameter. Second, we
find that the observed ratio of negative to positive drift rates in our sample
is 2.34, which, accounting for bias and sampling uncertainty, implies an actual
ratio of . This ratio has a vanishingly small probability of
occurring due to chance or statistical noise. The observed ratio of retrograde
to prograde rotators is two times lower than the ratio expected from numerical
predictions from NEA population studies and traditional assumptions about the
sense of rotation of NEAs originating from various main belt escape routes. We
also examine the efficiency with which solar energy is converted into orbital
energy and find a median efficiency in our sample of 12%. We interpret this
efficiency in terms of NEA spin and thermal properties.Comment: 27 pages, 9 figures, published in the Astronomical Journal, 159, 92,
202
Spin-Charge Decoupling and Orthofermi Quantum Statistics
Currently Gutzwiller projection technique and nested Bethe ansatz are two
main methods used to handle electronic systems in the infinity limit. We
demonstrate that these two approaches describe two distinct physical systems.
In the nested Bethe ansatz solutions, there is a decoupling between the spin
and charge degrees of freedom. Such a decoupling is absent in the Gutzwiller
projection technique. Whereas in the Gutzwiller approach, the usual
antisymmetry of space and spin coordinates is maintained, we show that the
Bethe ansatz wave function is compatible with a new form of quantum statistics,
viz., orthofermi statistics. In this statistics, the wave function is
antisymmetric in spatial coordinates alone. This feature ultimately leads to
spin-charge decoupling.Comment: 12 pages, LaTex Journal_ref: A slightly abridged version of this
paper has appeared as a brief report in Phys. Rev. B, Vol. 63, 132405 (2001
On p-adic lattices and Grassmannians
It is well-known that the coset spaces G(k((z)))/G(k[[z]]), for a reductive
group G over a field k, carry the geometric structure of an inductive limit of
projective k-schemes. This k-ind-scheme is known as the affine Grassmannian for
G. From the point of view of number theory it would be interesting to obtain an
analogous geometric interpretation of quotients of the form
G(W(k)[1/p])/G(W(k)), where p is a rational prime, W denotes the ring scheme of
p-typical Witt vectors, k is a perfect field of characteristic p and G is a
reductive group scheme over W(k). The present paper is an attempt to describe
which constructions carry over from the function field case to the p-adic case,
more precisely to the situation of the p-adic affine Grassmannian for the
special linear group G=SL_n. We start with a description of the R-valued points
of the p-adic affine Grassmannian for SL_n in terms of lattices over W(R),
where R is a perfect k-algebra. In order to obtain a link with geometry we
further construct projective k-subvarieties of the multigraded Hilbert scheme
which map equivariantly to the p-adic affine Grassmannian. The images of these
morphisms play the role of Schubert varieties in the p-adic setting. Further,
for any reduced k-algebra R these morphisms induce bijective maps between the
sets of R-valued points of the respective open orbits in the multigraded
Hilbert scheme and the corresponding Schubert cells of the p-adic affine
Grassmannian for SL_n.Comment: 36 pages. This is a thorough revision, in the form accepted by Math.
Zeitschrift, of the previously published preprint "On p-adic loop groups and
Grassmannians
Cryptographic Randomized Response Techniques
We develop cryptographically secure techniques to guarantee unconditional
privacy for respondents to polls. Our constructions are efficient and
practical, and are shown not to allow cheating respondents to affect the
``tally'' by more than their own vote -- which will be given the exact same
weight as that of other respondents. We demonstrate solutions to this problem
based on both traditional cryptographic techniques and quantum cryptography.Comment: 21 page
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