Deep drawable ultra low carbon Ti IF steels hot rolled in the ferrite region

The control of the amount of solute carbon in ultra low carbon Ti IF steels during ferrite rolling and subsequent recrystallization is of prime importance for the development of an appropriate recrystallization texture and for the production of thin deep drawable hot strips. In the present work, the effect of the solute carbon content and the rolling conditions on the recrystallization texture after ferrite rolling and on the corresponding Lankford value was quantified. Therefore, ultra low carbon Ti IF steels with different sulphur and titanium contents were rolled in the ferrite region, in order to obtain a variation in solute carbon content (from 0 to about 10 ppm) at the ferritic rolling temperatures. It was shown that a deep drawing grade (r_mean> 1.4) can be obtained if the chemical composition of the steel guarantees a complete stabilisation of the solute carbon in the austenitic temperature region and if sufficient strain (85%) is given in the finishing train at temperatures lower than about 800°C. It can be concluded that the sulphur and titanium contents have to be chosen slightly higher in comparison to the conventional Ti IF steel grades used for cold rolling and annealing.     

Combined growth of carbon nanotubes and carbon nanowalls by plasma-enhanced chemical vapor deposition

A technique is reported for the combined growth of carbon nanotubes (CNTs) and carbon nanowalls (CNWs) by plasma-enhanced chemical vapor deposition. The observation serves as a direct proof of a close correlation between the growth of both materials because both are obtained in a single experiment without making any changes to the growth parameters. The growth of freestanding CNTs is driven by a nickel catalyst deposited on an oxidized silicon wafer. It is assumed that the remaining carbon radicals are inserted in the sidewalls and tips of the tubes after the saturation of the catalyst by abundant carbon, thereby forming a CNW layer on top of the CNTs. A possible growth scheme, based on qualitative analysis by electron microscopy, Raman spectroscopy and X-ray diffraction, is presented. It is further shown that the CNWs easily detach by dipping the sample into water, while the CNTs remain attached to the sample.     

Investigation of the self-healing properties of shape memory polyurethane coatings with the ‘odd random phase multisine’ electrochemical impedance spectroscopy

The aim of this work is to study the physical self-healing properties of shape memory polyurethanes (SMPUs) with cerium ions on top of a pure aluminum substrate. To achieve this, the ‘odd random phase multisine’ electrochemical impedance spectroscopy (EIS) is used. The additional information given by this technique (stochastic noise, non-linear and non-stationary behavior of the sample during the measurement) has been useful to verify the quality of the measurement. Moreover, combined with a fitting algorithm weighted by the stochastic noise, these elements of information proved powerful in rejecting, accepting or improving electrical equivalent circuit models used to fit the impedance spectra.These SMPU consist of two parts: a soft matrix in caprolactone and a hard part in polyurethane. SMPU with 12, 30 and 41% of hard phase were investigated. The results showed that a physical self-healing can be observed for the coating with 12% of hard phase.     

Synchrotron X-Rays for Microstructural Investigations of Advanced Reactor Materials

X-rays from synchrotron beamlines provide a powerful tool for materials analysis in circumstances where long-term materials degradation under complex loading conditions (e.g., temperature, irradiation, and stress) becomes important. This may occur for advanced gas cooled reactors. Synchrotron X-rays can help to improve lifetime assessments by providing a more in-depth understanding of microstructural damage. This article summarizes results of X-ray absorption fine spectrum analysis and X-ray magnetic circular dichroism synchrotron techniques. They were employed to evaluate various microstructural features, which are important in understanding the lifetime of materials exposed to extreme conditions. Dispersoid strengthening by yttria particles, conditions that produce nanocrystal Zircaloy, and the role of magnetism on the stability of ferritic steels were taken as examples.     

Nouveaux conducteurs ioniques caracterises par une structure a tunnels entrecroises

The ionic conductivity of pyrochlores A_1+α(Ta_1+αW_1?α)O₆ was investigated for A = Na and T1. The thallium compounds are rather good conductors (0.34 ≤ ΔE ≤ 0.40 eV and $\text{5 10}{}^{\mathrm{?8}}\text{(Θ}\text{cm}\text{)}{}^{\mathrm{?1}}\text{≤}{}^{\mathrm{\sigma }}\text{25°}\text{C}\text{≤ 5.5 10}{}^{\mathrm{?5}}\text{(Θ}\text{cm}\text{)}{}^{\mathrm{?1}}$); the sodium oxides are poor conductors (0.76 eV ≤ ΔE ≤ 1.48 eV and $\text{10}{}^{\mathrm{?7}}\text{(Θ}\text{cm}\text{)}{}^{\mathrm{?1}}\text{≤}{}^{\mathrm{\sigma }}\text{500}\text{K}\text{≤ 10}{}^{\mathrm{?5}}\text{(Θ}\text{cm}\text{)}{}^{\mathrm{?1}}$). The differences between these two classes of pyrochlores are explained in terms of structure. New non-stoechiometric oxides T1_12+x(M_30+xW_3?x)O₉₀, with M = Ta, Nb, and 0 ≤ x ≤ 3, were isolated. They are, like pyrochlores, characterized by an intersecting tunnel structure, which is an intergrowth of pyrochlore and A₂M₇O₁₈ structures. These oxides show ionic conduction properties which are very close to those of pyrochlores: the tantalum oxides are better conductors (0.30 eV ≤ ΔE ≤ 0.37 eV ; $\text{3.6 10}{}^{\mathrm{?7}}\text{(Θ}\text{cm}\text{)}{}^{\mathrm{?1}}\text{≤}{}^{\mathrm{\sigma }}\text{25°}\text{C}\text{≤ 1.4 10}{}^{\mathrm{?6}}\text{(Θ}\text{cm}\text{)}{}^{\mathrm{?1}}$) than the niobium oxides (0.36 eV ≤ ΔE ≤ 0.42 eV ; $\text{10}{}^{\mathrm{?7}}\text{(Θ}\text{cm}\text{)}{}^{\mathrm{?1}}\text{≤}{}^{\mathrm{\sigma }}\text{25°}\text{C}\text{≤ 3.8 10}{}^{\mathrm{?7}}\text{(Θ}\text{cm}\text{)}{}^{\mathrm{?1}}$). The evolution ofionic conduction properties of all these compounds is discussed.     

A framework based on the extended Wyman concept for analyzing the salt effects on the solute retention in high-performance affinity chromatography.

The analysis of binding data of a ligand to a macromolecule in the presence of an additive can be classically formulated in terms of the linked functions of Wyman. In the case of a salt, this approach has been extended by Tanford such that the contributions of both salt and water are taken into account. In this paper, the extended Wyman theory was applied to high-performance affinity chromatography (HPAC) in order to define a general model describing the effects of the mobile-phase salts on the ligand binding. Various HPAC literature data, as well as our data concerning dansyl amino acid retention on a vancomycin stationary phase, were examined in relation to this model. From the results, this theoretical approach was considered to be adequate to describe accurately the salt dependence on solute retention. This work shows the importance of taking into account the effects of both ionic species and water in the investigation of relative contributions of the interactions involved in the ligand binding to immobilized receptor.     

Role of data and judgment in modeling human errors

Human beings are not a simple component. This is why prediction of human behaviour in a quantitative way is so difficult. For human reliability analysis, the data sources that can be used are the following: operating experience and incident reports, data banks, data from literature, data collected from simulators, data established by expert judgment. The factors important for conducting a good human reliability analysis are then discussed, including the uncertainties to be associated with.     

Pénétration d’impulsions électromagnétiques à l’intérieur des bâtiments en béton armé

This paper represents the repartition of an electromagnetic field inside a building modelised by parallel wires. This problem of diffraction is worked out with equations solved directly in the time domain. These equations are resolved by applying the moment method associated with the utilization of Lagrange interpolation polynoms. Applications to metallic structures responses to electromagnetic pulses illumination are presented.