183,452 research outputs found
Experience on the use of MOSTAB-HFW computer code for horizontal-axis wind turbines
Three topics are covered dealing with the frequencies of a rotating beam, the use of the fundamental mode of a uniform cantilever beam, and the analysis of resonance dwell. Immensely high peak loads were generated by the code for resonance dwell indicating further need for including structural damping and for transient analysis capability. The effect of structural damping, newly incorporated in the code, is described
Dynamic instability of ducts conveying fluid
A finite element analysis was used to study dynamic instability in ducts conveying high speed fluids. Ducts examined include cantilevered curved, flexibly supported, arbitrarily shaped, and composite duct systems. Partial differential equations were used to study the duct systems
Bosonization for 2D Interacting Fermion Systems: Non-Fermi Liquid Behavior
Non-Fermi liquid behavior is found for the first time in a two-dimensional
(2D) system with non-singular interactions using Haldane's bosonization scheme.
The bosonized system is solved exactly by a generalized Bogoliubov
transformation. The fermion momentum distribution, calculated using a
generalized Mattis-Lieb technique, exhibits a non-universal power law in the
vicinity of the Fermi surface for intermediate interaction strengths.Comment: 13 pages, 2 figures upon request, latex. (to appear in Mod. Phys.
Lett. B
Dibaryons with two heavy quarks
The relativistic six-quark equations are constructed in the framework of the
dispersion relation technique. The relativistic six-quark amplitudes of
dibaryons including the light , and heavy , quarks are
calculated. The approximate solutions of these equations using the method based
on the extraction of leading singularities of the heavy hexaquark amplitudes
are obtained. The poles of these amplitudes determine the masses of charmed and
bottom dibaryons with the isospins I=0, 1, 2 and the spin-parities ,
, .Comment: 10 pages, types corrected. arXiv admin note: substantial text overlap
with arXiv:1105.081
Single-index quantile regression
This is the post-print version of the final paper published in Journal of Multivariate Analysis. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2010 Elsevier B.V.Nonparametric quantile regression with multivariate covariates is a difficult estimation problem due to the “curse of dimensionality”. To reduce the dimensionality while still retaining the flexibility of a nonparametric model, we propose modeling the conditional quantile by a single-index function View the MathML sourceg0(xTγ0), where a univariate link function g0(⋅)g0(⋅) is applied to a linear combination of covariates View the MathML sourcexTγ0, often called the single-index. We introduce a practical algorithm where the unknown link function g0(⋅)g0(⋅) is estimated by local linear quantile regression and the parametric index is estimated through linear quantile regression. Large sample properties of estimators are studied, which facilitate further inference. Both the modeling and estimation approaches are demonstrated by simulation studies and real data applications
Envelope Expansion with Core Collapse. III. Similarity Isothermal Shocks in a Magnetofluid
We explore MHD solutions for envelope expansions with core collapse (EECC)
with isothermal MHD shocks in a quasi-spherical symmetry and outline potential
astrophysical applications of such magnetized shock flows. MHD shock solutions
are classified into three classes according to the downstream characteristics
near the core. Class I solutions are those characterized by free-fall collapses
towards the core downstream of an MHD shock, while Class II solutions are those
characterized by Larson-Penston (LP) type near the core downstream of an MHD
shock. Class III solutions are novel, sharing both features of Class I and II
solutions with the presence of a sufficiently strong magnetic field as a
prerequisite. Various MHD processes may occur within the regime of these
isothermal MHD shock similarity solutions, such as sub-magnetosonic
oscillations, free-fall core collapses, radial contractions and expansions. We
can also construct families of twin MHD shock solutions as well as an
`isothermal MHD shock' separating two magnetofluid regions of two different yet
constant temperatures. The versatile behaviours of such MHD shock solutions may
be utilized to model a wide range of astrophysical problems, including star
formation in magnetized molecular clouds, MHD link between the asymptotic giant
branch phase to the proto-planetary nebula phase with a hot central magnetized
white dwarf, relativistic MHD pulsar winds in supernova remnants, radio
afterglows of soft gamma-ray repeaters and so forth.Comment: 21 pages, 33 figures, accepted by MNRA
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