In situ and ex situ characterisation of oxide films formed on strained stainless steel surfaces in high-temperature water

A possible approach in describing the role of the environment in the phenomena behind initiation and propagation of a stress corrosion crack is to assume that the transport of matter and charge through the oxide film on the material is one of the rate-controlling factors. Straining of the bulk material may affect the transport rates of ionic defects, such as vacancies and interstitials, through the oxide film. The aim of the present work has been to verify the applicability of combined slow strain rate tests (SSRT) and contact electric resistance (CER) measurements to assess the influence of strain on the electric properties of oxide films on AISI 316L stainless steel with or without prior cold work in simulated boiling water reactor (BWR) coolant conditions. The SSRT-CER measurements have been combined with ex situ characterisation of the oxide films after experiments using electron spectroscopy for chemical analysis (ESCA) and scanning electron microscopy (SEM). The results suggest that the effect of strain on the resistance of the oxide films seems to correlate with the effect of the same parameter on the Cr(III) concentration in the inner layer of the oxide. In addition, important differences between the concentration of Ni and Fe in the outer layer formed on stressed and unstressed surface have been observed. Based on the mixed-conduction model for oxide films, an attempt is made to evaluate the effect of straining on the electric properties of the oxide films and to correlate these effects with the changes in film composition and structure.     

Characterizations of Sobolev inequalities on metric spaces

We discuss Maz'ya type isocapacitary characterizations of Sobolev inequalities on metric measure spaces.     

Stability for Parabolic Quasiminimizers

This paper studies parabolic quasiminimizers which are solutions to parabolic variational inequalities. We show that, under a suitable regularity condition on the boundary, parabolic Q-quasiminimizers related to the parabolic p-Laplace equations with given boundary values are stable with respect to parameters Q and p. The argument is based on variational techniques, higher integrability results and regularity estimates in time. This shows that stability does not only hold for parabolic partial differential equations but it also holds for variational inequalities.     

Fluctuation-limited noise in a superconducting transition-edge sensor

In order to investigate the origin of the until now unaccounted excess noise and to minimize the uncontrollable phenomena at the transition in x-ray microcalorimeters we have developed superconducting transition-edge sensors into an edgeless geometry, the so-called Corbino disk, with superconducting contacts in the center and at the outer perimeter. The measured rms current noise and its spectral density can be modeled as resistance noise resulting from fluctuations near the equilibrium superconductor-normal metal boundary.     

Inclusive∑ ± production in\bar pp interactions at 12 GeV/c

Inclusive production of∑ ^±(1385) resonances is studied in \(\bar pp\) interactions at 12 GeV/c. The cross sections for∑ ⁺(1385)+cc and∑ ^? are determined to be 251±38 μb and 123±30 μb, respectively. The inclusive spectra are presented as a function of Feynman x, c.m. rapidity and the squared transverse momentump _T ² . Significant differences with the correspondingpp data are found in the longitudinal momentum distributions. The qualitative features of the production can be explained by simple quark ideas.     

The influence of Bose-Einstein correlations on intermittency inp\bar p collisions at\sqrt s = 630 GeV

The influence of Bose-Einstein correlations on the rise of factorial moments is small in the 1-dimensional phase space given by the pseudorapidity η, where the 2-body correlation function is dominated by unlike-sign particle correlations. Contraily, the influence is dominant in the higher dimensional phase space. This is shown by using correlation integrals. They exhibit clear power law dependences on the four-momentum transferQ ² for all orders investigated (i=2–5). When searching for the origin of this behaviour, we found that the Bose-Einstein ratio itself shows a steep rise forQ ²→0, compatible with a power law.