Electrochemical analysis of austenitic stainless steel of type 304L SS in nitric acid medium

Austenitic stainless steels type 304L and 316L are largely used as structural materials for equipments handling nitric acid media in nuclear reprocessing plants. In almost all nitric media, these materials, protected by a chromium oxide rich layer, remain in their passive state. However, in some particular nitric media, their corrosion potential may be shifted towards their transpassive domain. The corrosion potential of the steel depends greatly on the cathodic reaction involved in the oxidoreduction process between the elements Fe, Cr, Ni of the steel and the oxidizing species of the medium. In this experiment, we have observed corrosion behavior of 304L SS by both electrochemical analysis and non-electrochemical analysis in different nitric acid concentrations such as 0.4M, 0.5M, 0.6M, 1M, 2M and concentrated solution. We measured corrosion rate and relation between corrosion current and corrosion rate by Tafel extrapolation method. Surface morphology of corroded surfaces were analysed by using AFM. The Micro hardness test was carried out to measure the hardness of both the non-corroded and corroded specimens. It is observed that the corrosion current density is inversely proportional to the corrosion potential and implies same pattern of corrosion tendency. The AFM results, we found that there is decreasing the density of pits on the surface by increasing concentration of nitric acid solution

Search for tau-neutrino interactions in the BEBC beam dump experiment

A novel and efficient kinematic method is used to estimate the number of ντ charged current interactions with Eν > 20 GeV in the BEBC beam dump experiment. The result, -14±12 ντ events, is consistent with zero. The ratio of Ds to D meson production in 400 GeV proton interactions in copper is estimated to be below 0.65 at 90% c.l. The oscillation probability P(νe→ντ) averaged over the electron-(anti)neutrino spectrum is found to be below 18%. The hypothesis that νe and ντ are identical is excluded by about 6 standard deviations. A remarkable event is described: it contains a muon, a high pT photon and a high pT hadron. © 1987

SEARCH FOR TAU-NEUTRINO INTERACTIONS IN THE BEBC BEAM DUMP EXPERIMENT

A novel and efficient kinematic method is used to estimate the number of ντ charged current interactions with Eν > 20 GeV in the BEBC beam dump experiment. The result, -14±12 ντ events, is consistent with zero. The ratio of Ds to D meson production in 400 GeV proton interactions in copper is estimated to be below 0.65 at 90% c.l. The oscillation probability P(νe→ντ) averaged over the electron-(anti)neutrino spectrum is found to be below 18%. The hypothesis that νe and ντ are identical is excluded by about 6 standard deviations. A remarkable event is described: it contains a muon, a high pT photon and a high pT hadron. © 1987

BOUNDS ON LIGHT GLUINOS FROM THE BEBC BEAM DUMP EXPERIMENT

Observational upper limits on anomalous neutral-current events in a proton beam dump experiment are used to constrain the possible hadroproduction and decay of light gluinos. These results require ifmg̃ $ ̌4 GeV for ifmq̃ - minw. © 1985

SEARCH FOR HEAVY NEUTRINO DECAYS IN THE BEBC BEAM DUMP EXPERIMENT

New limits on lepton mixing parameters are derived from a search for decays of heavy neutrinos in a proton beam dump experiment. The limits |Uøi|2, |Uei|2 < 10-6-10-7 are obtained for neutrino mass eigenstates vi of mass between 0.5 and 1.75 GeV, which can be produced through mixing in charmed D meson decays. This is the first such limit on |Uøi|2 for neutrino masses greater than 0.5 GeV. For the mass eigenstate v3 in particular, we obtain the limits |Uø3|2 < 10-7-10-8, |Ue3|2 < 10-9-10-10 for the mass range 150-190 MeV, assuming the v3 to be produced directly in charmed F meson decays. © 1985