Irreversible reduction of foil tension due to aerodynamical effects

Computation of the residual stress generated during the winding of a plastic film has been coped with by many authors. These studies are based on the assumption that the residual stresses mainly depend on two winding factors: (i) nominal foil tension and (ii) foil mechanical properties. Recently, several authors have introduced the effects of a third winding factor: nip force. But, in all the existing studies, the influence of the entrapped air layer and more generally, the aerodynamical effects are neglected.Such an assumption is reasonable in the case of thick plastic film (thickness about 100 μm) or thin plastic films (thickness about 10 μm) wound under low velocities (about 1 m.s-1). However, in the case of industrial winding conditions in which film thickness is typically about 10 μm and velocity about 5 m.s-1, the effects of aerodynamical phenomena are experimentally known to be as important as the effects of foil tension itself.From a more general point of view, the industrial winding conditions suffer from a lack of theoretical analysis since they are mainly based on empirism, which is not quite satisfactory.We recently proposed a model in order to predict the residual stresses generated under realistic industrial conditions, including the effect of nip roll. This model is based on a new global approach in which the Winding process is seen as a mechanism of air entrainment and air exhaust To set this model in order, we were faced with several problems: (i) computation of the thickness of the entrained air layer, (ii) analysis of the air exhaust phenomena, (iii) analysis of effects due to film roughness ... All the main parameters which govern the winding process (velocity, foil tension, nip force, foil bulk and surface properties ... ) are taken into account.In the present paper, we propose to recall the basis of this new global approach and to focus our attention on one of its most important consequences: the irreversible reduction of foil tension during and after winding. Experimental check is presented for a large set of winding conditions. Comparison is based on the average air layer thickness and on the foil residual tension value

Coupled-channels description of the 40Ca + 58,64Ni transfer and fusion reactions

Preliminary experimental data for nucleon transfer reactions of the 40Ca + 58Ni and 40Ca + 64Ni systems are analyzed with the coupled-channels approach. It is shown that a simple treatment for the transfer in the coupled-channels method cannot reproduce simultaneously the transfer probabilities and the subbarrier enhancement of fusion cross sections

Dissecting and modeling photic and melanopsin effects to predict sleep disturbances induced by irregular light exposure in mice.

Artificial lighting, day-length changes, shift work, and transmeridian travel all lead to sleep-wake disturbances. The nychthemeral sleep-wake cycle (SWc) is known to be controlled by output from the central circadian clock in the suprachiasmatic nuclei (SCN), which is entrained to the light-dark cycle. Additionally, via intrinsically photosensitive retinal ganglion cells containing the photopigment melanopsin (Opn4), short-term light-dark alternations exert direct and acute influences on sleep and waking. However, the extent to which longer exposures typically experienced across the 24-h day exert such an effect has never been clarified or quantified, as disentangling sustained direct light effects (SDLE) from circadian effects is difficult. Recording sleep in mice lacking a circadian pacemaker, either through transgenesis (Syt10 <sup>cre/cre</sup> Bmal1 <sup>fl/-</sup> ) or SCN lesioning and/or melanopsin-based phototransduction (Opn4 <sup>-/-</sup> ), we uncovered, contrary to prevailing assumptions, that the contribution of SDLE is as important as circadian-driven input in determining SWc amplitude. Specifically, SDLE were primarily mediated (>80%) through melanopsin, of which half were then relayed through the SCN, revealing an ancillary purpose for this structure, independent of its clock function in organizing SWc. Based on these findings, we designed a model to estimate the effect of atypical light-dark cycles on SWc. This model predicted SWc amplitude in mice exposed to simulated transequatorial or transmeridian paradigms. Taken together, we demonstrate this SDLE is a crucial mechanism influencing behavior on par with the circadian system. In a broader context, these findings mandate considering SDLE, in addition to circadian drive, for coping with health consequences of atypical light exposure in our society

Isotopic effects in sub-barrier fusion of Si + Si systems

Background: Recent measurements of fusion cross sections for the 28Si+28Si system revealed a rather unsystematic behavior ; i.e., they drop faster near the barrier than at lower energies. This was tentatively attributed to the large oblate deformation of 28Si because coupled-channels (CC) calculations largely underestimate the 28Si+28Si cross sections at low energies, unless a weak imaginary potential is applied, probably simulating the deformation. 30Si has no permanent deformation and its low-energy excitations are of a vibrational nature. Previous measurements of this system reached only 4 mb, which is not sufficient to obtain information on effects that should show up at lower energies. Purpose: The aim of the present experiment was twofold: (i) to clarify the underlying fusion dynamics by measuring the symmetric case 30Si+30Si in an energy range from around the Coulomb barrier to deep sub-barrier energies, and (ii) to compare the results with the behavior of 28Si+28Si involving two deformed nuclei. Methods: 30Si beams from the XTU tandem accelerator of the Laboratori Nazionali di Legnaro of the Istituto Nazionale di Fisica Nucleare were used, bombarding thin metallic 30Si targets (50 μg/cm2) enriched to 99.64% in mass 30. An electrostatic beam deflector allowed the detection of fusion evaporation residues (ERs) at very forward angles, and angular distributions of ERs were measured. Results: The excitation function of 30Si+30Si was measured down to the level of a few microbarns. It has a regular shape, at variance with the unusual trend of 28Si+28Si. The extracted logarithmic derivative does not reach the LCS limit at low energies, so that no maximum of the S factor shows up. CC calculations were performed including the low-lying 2+ and 3− excitations. Conclusions: Using a Woods-Saxon potential the experimental cross sections at low energies are overpredicted, and this is a clear sign of hindrance, while the calculations performed with a M3Y + repulsion potential nicely fit the data at low energies, without the need of an imaginary potential. The comparison with the results for 28Si+28Si strengthens the explanation of the oblate shape of 28Si being the reason for the irregular behavior of that system

Fusion Hindrance and Quadrupole Collectivity in Collisions of A≃50 Nuclei: The Case of 48Ti + 58Fe

International audience; The fusion excitation function of Ti-48 + Fe-58 has been measured in a wide energy range around the Coulomb barrier, covering 6 orders of magnitude of the cross sections. We present here the preliminary results of this experiment, and a full comparison with the near-by system Ni-58 + Fe-54 where evidence of fusion hindrance shows up at relatively high cross sections. The sub-barrier cross sections of Ti-48 + Fe-58 are much larger than those of Ni-58 + Fe-54. Significant differences are also observed in the logarithmic derivatives, astrophysical S-factors and fusion barrier distributions. The influence of low-energy nuclear structure on all these trends is pointed out and commented. Coupled-channels calculations using a Woods-Saxon potential are able to reproduce the experimental results for Ti-48 + Fe-58. The logarithmic derivative of the excitation function is very nicely fit, and no evidence of hindrance is observed down to around 1 mu b. The fusion barrier distribution is rather wide, flat and structureless. It is only in qualitative agreement with the calculated distribution

On geometry of cones and some applications

In this work we prove that in any normed space, the origin is a denting point of a pointed cone if and only if it is a point of continuity for the cone and the closure of the cone in the bidual space with respect to the weak* topology is pointed. Other related results and consequences are also stated. For example, a criterion to know whether a cone has a bounded base, an unbounded base, or does not have any base; and a result on the existence of super efficient points in weakly compact sets. (C) 2015 Elsevier Inc. All rights reserved.We thank the referee for suggestions that helped to improve the overall aspect of the manuscript. This work has been partially supported by the Generalitat Valenciana project GV/2014/072 (F. Garcia Castano) and by the Ministerio de Economia y Competitividad and FEDER project MTM2014-57838-C2-2-P (V. Montesinos).Garcia Castano, F.; Melguizo Padial, MA.; Montesinos Santalucia, V. (2015). On geometry of cones and some applications. Journal of Mathematical Analysis and Applications. 431(2):1178-1189. https://doi.org/10.1016/j.jmaa.2015.06.029S11781189431

Three-grating monolithic phase-mask for the single-order writing of large-period gratings

A new type of achromatic high-efficiency monolithic phase mask is presented. The mask comprises three submicron period diffraction gratings at a single substrate side that create a purely single spatial frequency interferogram of large period. The optical scheme is that of an integrated Mach-Zehnder interferometer where all light circulation functions are performed by diffraction gratings. The paper describes the operation principle of the phase mask, the fabrication process, and its utilization in a write-on-the-fly scheme for the writing of a long, 2 µm-period grating