46,558 research outputs found
Precipitation detector Patent
Precipitation detector and mechanism for stopping and restarting machinery at initiation and cessation of rai
Single and Many Particle Correlation Functions and Uniform Phase Bases for Strongly Correlated Systems
The need for suitable many or infinite fermion correlation functions to
describe some low dimensional strongly correlated systems is discussed. This is
linked to the need for a correlated basis, in which the ground state may be
postive definite, and in which single particle correlations may suffice. A
particular trial basis is proposed, and applied to a certain quasi-1D model.
The model is a strip of the 2D square lattice wrapped around a cylinder, and is
related to the ladder geometries, but with periodic instead of open boundary
conditions along the edges. Analysis involves a novel mean-field approach and
exact diagonalisation. The model has a paramagnetic region and a Nagaoka
ferromagnetic region. The proposed basis is well suited to the model, and
single particle correlations in it have power law decay for the paramagnet,
where the charge motion is qualitatively hard core bosonic. The mean field also
leads to a BCS-type model with single particle long range order.Comment: 23 pages, in plain tex, 12 Postscript figures included. Accepted for
publication in J.Physics : Condensed Matte
Effects of the roller feed ratio on wrinkling failure in conventional spinning of a cylindrical cup
In this study, wrinkling failure in conventional spinning of a cylindrical cup has been investigated by using both finite element (FE) analysis and experimental methods. FE simulation models of a spinning experiment have been developed using the explicit finite element solution method provided by the software Abaqus. The severity of wrinkles is quantified by calculating the standard deviation of the radial coordinates of element nodes on the edge of the workpiece obtained from the FE models. The results show that the severity of wrinkles tends to increase when increasing the roller feed ratio. A forming limit study for wrinkling has been carried out and shows that there is a feed ratio limit beyond which the wrinkling failure will take place. Provided that the feed ratio is kept below this limit, the wrinkling failure can be prevented. It is believed that high compressive tangential stresses in the local forming zone are the causes of the wrinkling failure. Furthermore, the computational performance of the solid and shell elements in simulating the spinning process are examined and the tool forces obtained from wrinkling and wrinkle-free models are compared. Finally, the effects of the feed ratio on variations of the wall thickness of the spun cylindrical cup are investigated. </jats:p
Killing Spinors for the Bosonic String
We obtain the effective action for the bosonic string with arbitrary
Yang-Mills fields, up to the \alpha' order, in general dimensions. The form of
the action is determined by the requirement that the action admit well-defined
Killing spinor equations, whose projected integrability conditions give rise to
the full set of equations of motion. The success of the construction suggests
that the hidden "pseudo-supersymmetry" associated with the Killing spinor
equations may be a property of the bosonic string itself.Comment: 9 page
Effect of time delay on feedback control of a flashing ratchet
It was recently shown that the use of feedback control can improve the
performance of a flashing ratchet. We investigate the effect of a time delay in
the implementation of feedback control in a closed-loop collective flashing
ratchet, using Langevin dynamics simulations. Surprisingly, for a large
ensemble, a well-chosen delay time improves the ratchet performance by allowing
the system to synchronize into a quasi-periodic stable mode of oscillation that
reproduces the optimal average velocity for a periodically flashing ratchet.
For a small ensemble, on the other hand, finite delay times significantly
reduce the benefit of feedback control for the time-averaged velocity, because
the relevance of information decays on a time scale set by the diffusion time
of the particles. Based on these results, we establish that experimental use of
feedback control is realistic.Comment: 6 pages, 6 figures, to appear in Europhysics Letter
Lipid changes within the epidermis of living skin equivalents observed across a time-course by MALDI-MS imaging and profiling
© 2015 Mitchell et al. Abstract Background: Mass spectrometry imaging (MSI) is a powerful tool for the study of intact tissue sections. Here, its application to the study of the distribution of lipids in sections of reconstructed living skin equivalents during their development and maturation is described. Methods: Living skin equivalent (LSE) samples were obtained at 14 days development, re-suspended in maintenance medium and incubated for 24 h after delivery. The medium was then changed, the LSE re-incubated and samples taken at 4, 6 and 24 h time points. Mass spectra and mass spectral images were recorded from 12 μm sections of the LSE taken at each time point for comparison using matrix assisted laser desorption ionisation mass spectrometry. Results: A large number of lipid species were identified in the LSE via accurate mass-measurement MS and MSMS experiments carried out directly on the tissue sections. MS images acquired at a spatial resolution of 50 μm × 50 μm showed the distribution of identified lipids within the developing LSE and changes in their distribution with time. In particular development of an epidermal layer was observable as a compaction of the distribution of phosphatidylcholine species. Conclusions: MSI can be used to study changes in lipid composition in LSE. Determination of the changes in lipid distribution during the maturation of the LSE will assist in the identification of treatment responses in future investigations
Pragmatic View of Short-Baseline Neutrino Oscillations
We present the results of global analyses of short-baseline neutrino
oscillation data in 3+1, 3+2 and 3+1+1 neutrino mixing schemes. We show that
the data do not allow us to abandon the simplest 3+1 scheme in favor of the
more complex 3+2 and 3+1+1 schemes. We present the allowed region in the 3+1
parameter space, which is located at between 0.82 and 2.19
at . The case of no oscillations is disfavored by about
, which decreases dramatically to about if the LSND data are
not considered. Hence, new high-precision experiments are needed to check the
LSND signal.Comment: 6 pages. Final version published in Phys. Rev. D 88, 073008 (2013
Short-Baseline Electron Neutrino Oscillation Length After Troitsk
We discuss the implications for short-baseline electron neutrino
disappearance in the 3+1 mixing scheme of the recent Troitsk bounds on the
mixing of a neutrino with mass between 2 and 100 eV. Considering the Troitsk
data in combination with the results of short-baseline nu_e and antinu_e
disappearance experiments, which include the reactor and Gallium anomalies, we
derive a 2 sigma allowed range for the effective neutrino squared-mass
difference between 0.85 and 43 eV^2. The upper bound implies that it is likely
that oscillations in distance and/or energy can be observed in radioactive
source experiments. It is also favorable for the ICARUS@CERN experiment, in
which it is likely that oscillations are not washed-out in the near detector.
We discuss also the implications for neutrinoless double-beta decay.Comment: 5 pages. Final version published in Phys.Rev. D87 (2013) 01300
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