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Noncontacting ultrasonic and electromagnetic HTS tape NDE
Two noncontacting nondestructive evaluation techniques (electromagnetic and ultrasonic) for inspection of high temperature superconducting tapes are described. Results for Ag-clad BSCCO tapes are given
Inter- and intragrain currents in bulk melt-grown YBaCuO rings
A simple contactless method suitable to discern between the intergrain
(circular) current, which flows in the thin superconducting ring, and the
intragrain current, which does not cross the weakest link, has been proposed.
At first, we show that the intergrain current may directly be estimated from
the magnetic flux density measured by the Hall sensor positioned
in the special points above/below the ring center. The experimental
and the numerical techniques to determine the value are discussed. Being
very promising for characterization of a current flowing across the joints in
welded YBaCuO rings (its dependencies on the temperature and the external
magnetic field as well as the time dissipation), the approach has been applied
to study corresponding properties of the intra- and intergrain currents flowing
across the -twisted grain boundaries which are frequent in bulk
melt-textured YBaCuO samples. We present experimental data related to the flux
penetration inside a bore of MT YBaCuO rings both in the non-magnetized, virgin
state and during the field reversal. The shielding properties and their
dependence on external magnetic fields are also studied. Besides, we consider
the flux creep effects and their influence on the current re-distribution
during a dwell.Comment: 13 pages, 16 figures (EPS), RevTeX4. In the revised version,
corrections to perturbing effects near the weak links are introduced, one
more figure is added. lin
Light propagation in non-trivial QED vacua
Within the framework of effective action QED, we derive the light cone
condition for homogeneous non-trivial QED vacua in the geometric optics
approximation. Our result generalizes the ``unified formula'' suggested by
Latorre, Pascual and Tarrach and allows for the calculation of velocity shifts
and refractive indices for soft photons travelling through these vacua.
Furthermore, we clarify the connection between the light velocity shift and the
scale anomaly. This study motivates the introduction of a so-called effective
action charge that characterizes the velocity modifying properties of the
vacuum. Several applications are given concerning vacuum modifications caused
by, e.g., strong fields, Casimir systems and high temperature.Comment: 13 pages, REVTeX, 3 figures, to appear in Phys. Rev.
Hydrography and circulation near the crest of the East Pacific Rise between 9° and 10°N
Author Posting. © The Author(s), 2010. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Deep Sea Research Part I: Oceanographic Research Papers 58 (2011): 365-376, doi:10.1016/j.dsr.2011.01.009.Topography has a strong effect on the physical oceanography over the flanks and crests of
the global mid-ocean ridge system. Here, we present an analysis of the hydrography and circulation near
the crest of the East Pacific Rise (EPR) between 9◦ and 10◦N, which coincides with an integrated study site
(ISS) of the RIDGE2000 program. The analysis is based primarily on survey and mooring data collected
during the LADDER project, which aimed to investigate oceanographic and topographic influences on larval
retention and dispersal in hydrothermal vent communities. Results indicate that the yearly averaged regional
mean circulation is characterized by a westward drift of 0.5–1 cm·s−1 across the EPR axis and by north- and
southward flows along the western and eastern upper ridge flanks, respectively. The westward drift is part
of a basin-scale zonal flow that extends across most of the Pacific ocean near 10◦N, whereas the meridional
currents near the ridge crest are a topographic effect. In spite of considerable mesoscale variability, which
dominates the regional circulation and dispersal on weekly to monthly time scales, quasi-synoptic surveys
carried out during the mooring deployment and recovery cruises indicate subinertial circulations that are
qualitatively similar to the yearly averaged flow but associated with significantly stronger velocities. Weekly
averaged mooring data indicate that the anticyclonically sheared along-flank flows are associated with core
speeds as high as 10 cm·s−1 and extend ≈10 km off axis and 200m above the ridge-crest topography. Near the
northern limit of the study region, the Lamont Seamount Chain rises from the western ridge flank and restricts
along-EPR flow to five narrow passages, where peak velocities in excess of 20 cm·s−1 were observed. Outside
the region of the ridge-crest boundary currents the density field over the EPR near 10◦N is characterized by
isopycnals dipping into the ridge flanks. Directly above the EPR axis the ridge-crest boundary currents give
rise to an isopycnal dome. During times of strong westward cross-EPR flow isopycnal uplift over the eastern
flank causes the cross-ridge density field below the doming isopycnals to be asymmetric, with higher densities
over the eastern than over the western flank. The data collected during the LADDER project indicate that
dispersal of hydrothermal products from the EPR ISS on long time scales is predominantly to the west,
whereas mesoscale variability dominates dispersal on weekly to monthly time scales, which are particularly
important in the context of larval dispersal.Co-funding of the LADDER project by the biological and physical oceanography
divisions of the National Science Foundation under grants OCE-0425361 and OCE-0424953 is gratefully
acknowledged, as is support of J.W. Lavelle by NOAA’s Pacific Marine Environmental Laboratory and by the
NOAA Vents Program
Branch-and-lift algorithm for deterministic global optimization in nonlinear optimal control
This paper presents a branch-and-lift algorithm for solving optimal control problems with smooth nonlinear dynamics and potentially nonconvex objective and constraint functionals to guaranteed global optimality. This algorithm features a direct sequential method and builds upon a generic, spatial branch-and-bound algorithm. A new operation, called lifting, is introduced, which refines the control parameterization via a Gram-Schmidt orthogonalization process, while simultaneously eliminating control subregions that are either infeasible or that provably cannot contain any global optima. Conditions are given under which the image of the control parameterization error in the state space contracts exponentially as the parameterization order is increased, thereby making the lifting operation efficient. A computational technique based on ellipsoidal calculus is also developed that satisfies these conditions. The practical applicability of branch-and-lift is illustrated in a numerical example. © 2013 Springer Science+Business Media New York
The interaction of child abuse and rs1360780 of the FKBP5 gene is associated with amygdala resting-state functional connectivity in young adults
The interaction of child abuse and rs1360780 of the FKBP5 gene is associated with amygdala resting-state functional connectivity in young adults
Towards the high-accuracy determination of the 238U fission cross section at the threshold region at CERN - N-TOF
The 238U fission cross section is an international standard beyond 2 MeV where the fission plateau starts. However, due to its importance in fission reactors, this cross-section should be very accurately known also in the threshold region below 2 MeV. The 238U fission cross section has been measured relative to the 235U fission cross section at CERN - n-TOF with different detection systems. These datasets have been collected and suitably combined to increase the counting statistics in the threshold region from about 300 keV up to 3 MeV. The results are compared with other experimental data, evaluated libraries, and the IAEA standards
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