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A method to take account of inhomogeneity in mechanical component reliability calculations
YesThis paper proposes a method by which material inhomogeneity may be taken into account in a reliability calculation. The method employs Monte-Carlo simulation; and introduces a material strength index, and a standard deviation of material strength to model the variation in the strength of a component throughout its volume. The method is compared to conventional load-strength interference theory. The results are identical for the case of homogeneous material, but reliability is shown to reduce for the same load as the component volume increases. The case of a tensile bar is used to explore the variation of reliability with component volume
Temperature Dependent Motion of a Massive Quantum Particle
We report model calculations of the time-dependent internal energy and
entropy for a single quasi-free massive quantum particle at a constant
temperature. We show that the whole process started from a fully coherent
quantum state to thermodynamic equilibrium can be understood, based on
statistics of diffracted matter waves. As a result of thermal interaction
between the particle and its surroundings, the motion of the particle shows new
feature.Comment: 3 figure
Latest Results on and at high
Recent progress from Jefferson Lab has significantly improved our
understanding of the nucleon spin structure in the high- region. Results of
a precision measurement of the neutron spin asymmetry, , in the high-
(valence quark) region are discussed. The up and down quark spin distributions
in the nucleon were extracted. was also measured. The results were
used, in combination with existing data, to extract the second moment, .
Preliminary results on and in the high- region have also
become available. Finally, the results of a precision measurement of the
structure function to study higher twist effects will be presented.Comment: 4 pages, 2 figures, to appear in the DIS2005 Proceedings (AIP
Gutzwiller Approximation in Degenerate Hubbard Models
Degenerate Hubbard models are studied using the
Generalized-Gutzwiller-Approximation. It is found that the metal-insulator
transition occurs at a finite correlation when the average number of
electrons per lattice site is an integer. The critical depends
sensitively on both the band degeneracy and the filling . A derivation
is presented for the general expression of which reproduces all
previously known Gutzwiller solutions, including that of the Boson Hubbard
model. Effects of the lattice structure on the metal-insulator transition and
the effective mass are discussed.Comment: RevTex file with 2 figures included, 12 page
Recovery of Sparse Signals Using Multiple Orthogonal Least Squares
We study the problem of recovering sparse signals from compressed linear
measurements. This problem, often referred to as sparse recovery or sparse
reconstruction, has generated a great deal of interest in recent years. To
recover the sparse signals, we propose a new method called multiple orthogonal
least squares (MOLS), which extends the well-known orthogonal least squares
(OLS) algorithm by allowing multiple indices to be chosen per iteration.
Owing to inclusion of multiple support indices in each selection, the MOLS
algorithm converges in much fewer iterations and improves the computational
efficiency over the conventional OLS algorithm. Theoretical analysis shows that
MOLS () performs exact recovery of all -sparse signals within
iterations if the measurement matrix satisfies the restricted isometry property
(RIP) with isometry constant The recovery performance of MOLS in the noisy scenario is also
studied. It is shown that stable recovery of sparse signals can be achieved
with the MOLS algorithm when the signal-to-noise ratio (SNR) scales linearly
with the sparsity level of input signals
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