40,879 research outputs found
Analysis of webs of partial-tension-field beams subjected to lateral pressure loadings
Webs of partial-tension-field beams subjected to lateral pressure loading
An investigation of the effects of surrounding structure on sonic fatigue
Effects of surrounding structure on sonic fatigu
String-Inspired Triplet See-Saw from Diagonal Embedding of SU(2)_L in SU(2)_A x SU(2)_B
Motivated by string constructions, we consider a variant on the Type II
see-saw mechanism involving the exchange of triplet representations of SU(2)_L
in which this group arises from a diagonal embedding into SU(2)_A x SU(2)_B. A
natural assignment of Standard Model lepton doublets to the two underlying
gauge groups results in a bimaximal pattern of neutrino mixings and an inverted
hierarchy in masses. Simple perturbations around this leading-order structure
can accommodate the observed pattern of neutrino masses and mixings.Comment: 8 pages; uses RevTe
Extracting Spooky-activation-at-a-distance from Considerations of Entanglement
Following an early claim by Nelson & McEvoy \cite{Nelson:McEvoy:2007}
suggesting that word associations can display `spooky action at a distance
behaviour', a serious investigation of the potentially quantum nature of such
associations is currently underway. This paper presents a simple quantum model
of a word association system. It is shown that a quantum model of word
entanglement can recover aspects of both the Spreading Activation equation and
the Spooky-activation-at-a-distance equation, both of which are used to model
the activation level of words in human memory.Comment: 13 pages, 2 figures; To appear in Proceedings of the Third Quantum
Interaction Symposium, Lecture Notes in Artificial Intelligence, vol 5494,
Springer, 200
Importance of Tests for the Complete Lorentz Structure of the t --> W+ b vertex at Hadron Colliders
The most general Lorentz-invariant decay-density-matrix for , or for , is expressed in terms
of eight helicity parameters. The parameters are physically defined in terms of
partial-width-intensities for polarized-final-states in decay.
The parameters are the partial width, the quark's chirality parameter
, the polarimetry parameter , a "pre-SSB" test parameter
, and four - interference parameters , ,
, which test for violation. They can be
used to test for non-CKM-type CP violation, anomalous 's, top
weak magnetism, weak electricity, and second-class currents. By stage-two
spin-correlation techniques, percent level statistical uncertainites are
typical for measurements at the Tevatron, and several mill level uncertainites
are typical at the LHC.Comment: Minor clarifications. Expression for r_{+-} corrected. 19 pages LaTex
+ Tables + 1 Figur
Defect-unbinding transitions and inherent structures in two dimensions
We present a large-scale (36000-particle) computational study of the
"inherent structures" (IS) associated with equilibrium, two-dimensional,
one-component Lennard-Jones systems. Our results provide strong support both
for the inherent-structures theory of classical fluids, and for the KTHNY
theory of two-stage melting in two dimensions. This support comes from the
observation of three qualitatively distinct "phases" of inherent structures: a
crystal, a "hexatic glass", and a "liquid glass". We also directly observe, in
the IS, analogs of the two defect-unbinding transitions (respectively, of
dislocations, and disclinations) believed to mediate the two equilibrium phase
transitions. Each transition shows up in the inherent structures---although the
free disclinations in the "liquid glass" are embedded in a percolating network
of grain boundaries. The bond-orientational correlation functions of the
inherent structures show the same progressive loss of order as do the three
equilibrium phases: long-range to quasi-long-range to short-range.Comment: RevTeX, 8 pages, 15 figure
Brane Isotropisation in Extra-Dimensional Tolman-Bondi Universe
We consider the dynamics of a 3-brane embedded in an extra-dimensional
Tolman-Bondi Universe where the origin of space plays a special role. The
embedding is chosen such that the induced matter distribution on the brane
respects the spherical symmetry of matter in the extra dimensional space. The
mirage cosmology on the probe brane is studied, resulting in an inhomogeneous
and anisotropic four dimensional cosmology where the origin of space is also
special. We then focus on the spatial geometry around the origin and show that
the induced geometry, which is initially inhomogeneous and anisotropic,
converges to an isotropic and homogeneous Friedmann-Lemaitre 4d space-time. For
instance, when a 3-brane is embedded in a 5d matter dominated model, the 4d
dynamics around the origin converge to a Friedmann-Lemaitre Universe in a
radiation dominated epoch. We analyse this isotropisation process and show that
it is a late time attractor.Comment: 16 pages, 8 figures, one reference adde
Conceptual design study of a coal gasification combined-cycle powerplant for industrial cogeneration
A conceptual design study was conducted to assess technical feasibility, environmental characteristics, and economics of coal gasification. The feasibility of a coal gasification combined cycle cogeneration powerplant was examined in response to energy needs and to national policy aimed at decreasing dependence on oil and natural gas. The powerplant provides the steam heating and baseload electrical requirements while serving as a prototype for industrial cogeneration and a modular building block for utility applications. The following topics are discussed: (1) screening of candidate gasification, sulfur removal and power conversion components; (2) definition of a reference system; (3) quantification of plant emissions and waste streams; (4) estimates of capital and operating costs; and (5) a procurement and construction schedule. It is concluded that the proposed powerplant is technically feasible and environmentally superior
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