OIM analysis of microstructure and texture of a TRIP assisted steel after static and dynamic deformation

TRIP-assisted steel with a composition of 0.2%C, 1.6%Mn, 1.5%Al was studied in the undeformed state, after the application of 10 and 30 % static tensile strain parallel to rolling the direction of the sheet and after dynamic (Hopkinson) fracture test. Detailed examination of the microstructure and microtexture by means of electron backscattered diffraction (EBSD) was carried out in order to quantify the microstructural constituents and to study the strain distribution. The microtexture evolution and the distribution of the specific texture components between the BCC and FCC phases were studied as a function of the external strain and the strain mode-static or dynamic. The strain localization and strain distribution between the structural constituents were quantified based on local misorientation maps. The full constraint Taylor model was used to predict the texture changes in the material and the results were compared to the experimental findings. Comparing the local misorientation data it was found that at low strains the ferrite accommodates approximately 10 times more deformation than the retained austenite. The strain localizes initially on the BCC-FCC phase boundaries and is then spread in the BCC constituents (ferrite and bainite) creating a deformation skeleton in the BCC phase. It was found that the observed texture changes in the measured retained austenite texture after deformation do not correspond exactly to the model prediction. The austenite texture components which were predicted by the Taylor model were not found in the measured austenite texture after deformation which means that they are first transformed to martensite, which is considered as an indication for the selective transformation of austenite under strain

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

A Very Intense Neutrino Super Beam Experiment for Leptonic CP Violation Discovery based on the European Spallation Source Linac: A Snowmass 2013 White Paper

Very intense neutrino beams and large neutrino detectors will be needed in order to enable the discovery of CP violation in the leptonic sector. We propose to use the proton linac of the European Spallation Source currently under construction in Lund, Sweden to deliver, in parallel with the spallation neutron production, a very intense, cost effective and high performance neutrino beam. The baseline program for the European Spallation Source linac is that it will be fully operational at 5 MW average power by 2022, producing 2 GeV 2.86 ms long proton pulses at a rate of 14 Hz. Our proposal is to upgrade the linac to 10 MW average power and 28 Hz, producing 14 pulses/s for neutron production and 14 pulses/s for neutrino production. Furthermore, because of the high current required in the pulsed neutrino horn, the length of the pulses used for neutrino production needs to be compressed to a few $\mu$s with the aid of an accumulator ring. A long baseline experiment using this Super Beam and a megaton underground Water Cherenkov detector located in existing mines 300-600 km from Lund will make it possible to discover leptonic CP violation at 5 $\sigma$ significance level in up to 50% of the leptonic Dirac CP-violating phase range. This experiment could also determine the neutrino mass hierarchy at a significance level of more than 3 $\sigma$ if this issue will not already have been settled by other experiments by then. The mass hierarchy performance could be increased by combining the neutrino beam results with those obtained from atmospheric neutrinos detected by the same large volume detector. This detector will also be used to measure the proton lifetime, detect cosmological neutrinos and neutrinos from supernova explosions. Results on the sensitivity to leptonic CP violation and the neutrino mass hierarchy are presented.Comment: 28 page

High intensity neutrino oscillation facilities in Europe

The EUROnu project has studied three possible options for future, high intensity neutrino oscillation facilities in Europe. The first is a Super Beam, in which the neutrinos come from the decay of pions created by bombarding targets with a 4 MW proton beam from the CERN High Power Superconducting Proton Linac. The far detector for this facility is the 500 kt MEMPHYS water Cherenkov, located in the Fréjus tunnel. The second facility is the Neutrino Factory, in which the neutrinos come from the decay of μ+ and μ− beams in a storage ring. The far detector in this case is a 100 kt magnetized iron neutrino detector at a baseline of 2000 km. The third option is a Beta Beam, in which the neutrinos come from the decay of beta emitting isotopes, in particular He6 and Ne18, also stored in a ring. The far detector is also the MEMPHYS detector in the Fréjus tunnel. EUROnu has undertaken conceptual designs of these facilities and studied the performance of the detectors. Based on this, it has determined the physics reach of each facility, in particular for the measurement of CP violation in the lepton sector, and estimated the cost of construction. These have demonstrated that the best facility to build is the Neutrino Factory. However, if a powerful proton driver is constructed for another purpose or if the MEMPHYS detector is built for astroparticle physics, the Super Beam also becomes very attractive

The ESSnuSB design study: overview and future prospects

ESSnuSB is a design study for an experiment to measure the CP violation in the leptonic sector at the second neutrino oscillation maximum using a neutrino beam driven by the uniquely powerful ESS linear accelerator. The reduced impact of systematic errors on sensitivity at the second maximum allows for a very precise measurement of the CP violating parameter. This review describes the fundamental advantages of measurement at the 2nd maximum, the necessary upgrades to the ESS linac in order to produce a neutrino beam, the near and far detector complexes, the expected physics reach of the proposed ESSnuSB experiment, concluding with the near future developments aimed at the project realization.Comment: 19 pages, 11 figures; Corrected minor error in alphabetical ordering of the authors: the author list is now fully alphabetical w.r.t. author surnames as was intended. Corrected an incorrect affiliation for two authors per their reques

Updated physics performance of the ESSnuSB experiment

In this paper, we present the physics performance of the ESSnuSB experiment in the standard three flavor scenario using the updated neutrino flux calculated specifically for the ESSnuSB configuration and updated migration matrices for the far detector. Taking conservative systematic uncertainties corresponding to a normalization error of for signal and for background, we find that there is CP violation discovery sensitivity for the baseline option of 540 km (360 km) at . The corresponding fraction of for which CP violation can be discovered at more than is . Regarding CP precision measurements, the error associated with is around and with is around for the baseline option of 540 km (360 km). For hierarchy sensitivity, one can have sensitivity for 540 km baseline except and sensitivity for 360 km baseline for all values of . The octant of can be determined at for the values of: ( and ) for baseline of 540 km (360 km). Regarding measurement precision of the atmospheric mixing parameters, the allowed values at are: () and eV eV ( eV eV) for the baseline of 540 km (360 km)