Observability of quality features of sheet metal parts based on metamodels

Deep drawn sheet metal parts are increasingly designed to the feasibility limit, thus achieving a robust process is often challenging. The fluctuation of process and material properties often leads to robustness problems. Especially skid impact lines can cause visible changes of the surface fine structure even after painting. Numerical simulations are used to detect critical regions and the influences on the skid impact lines. To enhance the agreement with the real process conditions, the measured material data and the force distribution are taken into account. The simulation metamodel contains the virtual knowledge of a particular forming process, which is determined based on a series of finite element simulations with variable input parameters. Based on these metamodels, innovative process windows can be displayed to determine the influences on the critical regions and on skid impact lines. By measuring the draw-in of the part, sensor positions can be identified. Each sensor observes the accordant quality criterion and is hence able to quantify potential splits, insufficient stretching, wrinkles or skid impact lines. Furthermore the virtual draw-in sensors and quality criteria are particularly useful for the assessment of the process observation of a subsequent process control

Compact vortex in a generalized Born-Infeld model

We study vortexlike solutions in a generalized Born-Infeld model. The model is driven by two distinct parameters, one which deals with the Born-Infeld term, and the other, which controls the presence of high-order power term in the covariant derivative of the Higgs field. We numerically solve the equations of motion and depict the main vortex features, for several values of the two parameters of the model. The results indicate the presence of compact vortex, when the parameter responsible for the high-order power in the derivative increases to sufficiently large values.Comment: 6 pages, 6 figures; version to appear in PR

Twinlike Models for Self-Dual Maxwell-Higgs Theories

In this work we present a theoretical framework that allows for the existence of coherent twinlike models in the context of self-dual Maxwell-Higgs theories. We verify the consistence of this framework by using it to develop some twinlike self-dual Maxwell-Higgs models. We use a combination of theoretical and numerical techniques to show that these models exhibit the very same topological BPS structures, including their field configurations and total energy. The study shows that it is possible to develop a completely consistent prescription, which extends the idea of twinlike models to the case of vortices in Maxwell-Higgs theories.Comment: 7 pages, 3 figures; version to appear in PR

Nontopological self-dual Maxwell-Higgs vortices

We study the existence of self-dual nontopological vortices in generalized Maxwell-Higgs models recently introduced in Ref. \cite{gv}. Our investigation is explicitly illustrated by choosing a sixth-order self-interaction potential, which is the simplest one allowing the existence of nontopological structures. We specify some Maxwell-Higgs models yielding BPS nontopological vortices having energy proportional to the magnetic flux, $\Phi_{B}$, and whose profiles are numerically achieved. Particularly, we investigate the way the new solutions approach the boundary values, from which we verify their nontopological behavior. Finally, we depict the profiles numerically found, highlighting the main features they present.Comment: 6 pages, 4 figure

Topological vortices in generalized Born-Infeld-Higgs electrodynamics

A consistent BPS formalism to study the existence of topological axially symmetric vortices in generalized versions of the Born-Infeld-Higgs electrodynamics is implemented. Such a generalization modifies the field dynamics via introduction of three non-negative functions depending only in the Higgs field, namely, $G(|\phi|)$, $w(|\phi|)$ and $V(|\phi|)$. A set of first-order differential equations is attained when these functions satisfy a constraint related to the Ampere law. Such a constraint allows to minimize the system energy in such way that it becomes proportional to the magnetic flux. Our results provides an enhancement of topological vortex solutions in Born-Infeld-Higgs electrodynamics. Finally, we analyze a set of models such that a generalized version of Maxwell-Higgs electrodynamics is recovered in a certain limit of the theory.Comment: 8 pages, 8 figures, to appear in EPJ

Generalized self-dual Chern-Simons vortices

We search for vortices in a generalized Abelian Chern-Simons model with a nonstandard kinetic term. We illustrate our results, plotting and comparing several features of the vortex solution of the generalized model with those of the vortex solution found in the standard Chern-Simons model.Comment: 7 pages, 7 figure

Infrared Observations of the Helix Planetary Nebula

We have mapped the Helix (NGC 7293) planetary nebula (PN) with the IRAC instrument on the Spitzer Space Telescope. The Helix is one of the closest bright PNs and therefore provides an opportunity to resolve the small-scale structure in the nebula. The emission from this PN in the 5.8 and 8 μm IRAC bands is dominated by the pure rotational lines of molecular hydrogen, with a smaller contribution from forbidden line emission such as [Ar III] in the ionized region. The IRAC images resolve the "cometary knots," which have been previously studied in this PN. The "tails" of the knots and the radial rays extending into the outer regions of the PN are seen in emission in the IRAC bands. IRS spectra on the main ring and the emission in the IRAC bands are consistent with shock-excited H_2 models, with a small (~10%) component from photodissociation regions. In the northeast arc, the H_2 emission is located in a shell outside the Hα emission

Long beating wavelength in the Schwarz-Hora effect

Thirty years ago, H.Schwarz has attempted to modulate an electron beam with optical frequency. When a 50-keV electron beam crossed a thin crystalline dielectric film illuminated with laser light, electrons produced the electron-diffraction pattern not only at a fluorescent target but also at a nonfluorescent target. In the latter case the pattern was of the same color as the laser light (the Schwarz-Hora effect). This effect was discussed extensively in the early 1970s. However, since 1972 no reports on the results of further attempts to repeat those experiments in other groups have appeared, while the failures of the initial such attempts have been explained by Schwarz. The analysis of the literature shows there are several unresolved up to now contradictions between the theory and the Schwarz experiments. In this work we consider the interpretation of the long-wavelength spatial beating of the Schwarz-Hora radiation. A more accurate expression for the spatial period has been obtained, taking into account the mode structure of the laser field within the dielectric film. It is shown that the discrepancy of more than 10% between the experimental and theoretical results for the spatial period cannot be reduced by using the existing quantum models that consider a collimated electron beam.Comment: 3 pages, RevTe

Thermal Phase Variations of WASP-12b: Defying Predictions

[Abridged] We report Warm Spitzer full-orbit phase observations of WASP-12b at 3.6 and 4.5 micron. We are able to measure the transit depths, eclipse depths, thermal and ellipsoidal phase variations at both wavelengths. The large amplitude phase variations, combined with the planet's previously-measured day-side spectral energy distribution, is indicative of non-zero Bond albedo and very poor day-night heat redistribution. The transit depths in the mid-infrared indicate that the atmospheric opacity is greater at 3.6 than at 4.5 micron, in disagreement with model predictions, irrespective of C/O ratio. The secondary eclipse depths are consistent with previous studies. We do not detect ellipsoidal variations at 3.6 micron, but our parameter uncertainties -estimated via prayer-bead Monte Carlo- keep this non-detection consistent with model predictions. At 4.5 micron, on the other hand, we detect ellipsoidal variations that are much stronger than predicted. If interpreted as a geometric effect due to the planet's elongated shape, these variations imply a 3:2 ratio for the planet's longest:shortest axes and a relatively bright day-night terminator. If we instead presume that the 4.5 micron ellipsoidal variations are due to uncorrected systematic noise and we fix the amplitude of the variations to zero, the best fit 4.5 micron transit depth becomes commensurate with the 3.6 micron depth, within the uncertainties. The relative transit depths are then consistent with a Solar composition and short scale height at the terminator. Assuming zero ellipsoidal variations also yields a much deeper 4.5 micron eclipse depth, consistent with a Solar composition and modest temperature inversion. We suggest future observations that could distinguish between these two scenarios.Comment: 19 pages, 10 figures, ApJ in press. Improved discussion of gravity brightenin

"Colliding beam" enhancement mechanism of deuteron-deuteron fusion reactions in matter

We suggest a ``ping-pong'' mechanism of enhancement for fusion reactions between a low energy external deuteron beam and the deuterons in a condensed matter or molecular target. The mechanism is based on the possibility of acceleration of a target deuteron by the Coulomb field of a projectile deuteron with its subsequent rebound from a heavy atom in matter and the following fusion of the two deuterons moving towards each other. This effectively converts the fixed target process into a colliding beam reaction. In a simple limiting case this reduces the negative penetrability exponent by a factor of $\sqrt{2}$. We also discuss a contribution given by ``zero oscillations'' of a bound target deuteron. The proposed mechanism is expected to be efficient in compounds with target deuterons localized in the vicinity of heavy atoms.Comment: 4 page