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Corrosion product identification and relative rates of corrosion of candidate metals in an irradiated air-steam environment (open access)

Corrosion product identification and relative rates of corrosion of candidate metals in an irradiated air-steam environment

Previously reported work by others indicates that dicopper trihydroxide nitrate, Cu{sub 2}NO{sub 3}(OH){sub 3}, forms on copper and copper alloys subjected to irradiated moist air near room temperature. We have performed experiments over a range of temperature and humidity, and have found that this species is formed at temperatures up to at least 150{degree}C if low to intermediate relative humidities are present. At 150{degree}C and 100% relative humidity, only Cu{sub 2}O and CuO were observed. The relative general corrosion rates of the copper materials tested in 1-month experiments at dose rates of 0.7 and 2.0 kGy/h were Cu > 70/30 Cu--Ni > Al-bronze. High-nickel alloy 825 showed no observable corrosion. 29 refs., 4 tabs.
Date: November 3, 1989
Creator: Reed, D. T.; Swayambunathan, V.; Tani, B. S. & Van Konynenburg, R. A.
System: The UNT Digital Library
Experimental Tests of Proton Spin Models (open access)

Experimental Tests of Proton Spin Models

We have developed models for the spin-weighted quark and gluon distribution in a longitudinally polarized proton. The model parameters are determined from current algebra sum rules and polarized deep-inelastic scattering data. A number of different scenarios are presented for the fraction of spin carried the constituent parton distributions. A possible long-range experimental program is suggested for measuring various hard scattering processes using polarized lepton and proton beams. With the knowledge gained from these experiments, we can begin to understand the parton contributions to the proton spin. 28 refs., 5 figs.
Date: November 3, 1989
Creator: Ramsey, G. P.
System: The UNT Digital Library
Saturating interactions in /sup 4/He with density dependence (open access)

Saturating interactions in /sup 4/He with density dependence

With the advent of larger and faster computers, as well as modern shell model codes, nuclear structure calculations for the light nuclei (A<16) which include full 2/bar h/..omega.. model spaces are quite feasible. However, there can be serious problems in the mixing of 2/bar h/..omega.. and higher excitations into the low-lying spectra if the effective interaction is non-saturating. Furthermore, effective interactions which are both saturating and density dependent have not generally been used in previous nuclear structure calculations. Therefore, we have undertaken studies of /sup 4/He using two-body potential interactions which incorporate both saturation and density-dependence. Encouraging initial results in remedying the mixing of 0 and 2/bar h/..omega.. excitations have been obtained. We have also considered the effects of our interaction on the /sup 4/He compressibility and the centroid of the breathing mode strength. First indications are that a saturating effective interaction, with a short-range density dependent part and a long-range density independent part, comes close to matching crude predictions for the compressibility of /sup 4/He. 11 refs., 6 tabs.
Date: May 3, 1989
Creator: Bloom, S.D.; Resler, D.A. & Moszkowski, S.A.
System: The UNT Digital Library
Z physics and tests of the standard model (open access)

Z physics and tests of the standard model

Fundamental aspects of Z physics are reviewed with an emphasis on e/sup +/e/sup /minus// annihilation. The effects of radiative corrections, both from ordinary QED and from the electroweak interactions are considered from an elementary point of view, but in some detail. The possibility of mixing with an extra Z boson is discussed. The implications for experiments are stressed. Additional information that will be obtained from measurements of the W in collider experiments is considered. 18 refs., 20 figs., 3 tabs.
Date: January 3, 1989
Creator: Cahn, R.N.
System: The UNT Digital Library
Atomic and molecular surface and volume processes in the analysis of negative hydrogen discharges (open access)

Atomic and molecular surface and volume processes in the analysis of negative hydrogen discharges

The principal source of negative ion generation in hydrogen discharges is now recognized to be low-energy electron attachment to H/sub 2/(/nu//prime//prime/) molecules excited to the middle portion of the vibrational spectrum. Electron excitation processes are generally taken to be the principal source of H/sub 2/(/nu//prime//prime/) generation, with high-energy excitations through the singlet spectrum being the principal excitation process populating the active portion of the vibrational spectrum. A description of the collisional re-excitation from level /nu//prime//prime/, to level /nu//prime//prime/, requires 15 /times/ 15 matrix of cross sections linking all initial and final levels. These cross sections have been evaluated and incorporated into the modelling code. An additional source of vibrational excitation may be derived from recombination of H/sub 2//sup +/ and H/sub 3//sup +/ ions on the surfaces of the discharge. In this case the molecular ions will impinge with kinetic energies given by the plasma potential, 1--10 eV. In this paper we report the evaluation of H/sub 2/(/nu//prime//prime/) resulting from the surface recombination process. The use of low-work-function materials for the discharge surfaces makes possible two additional source of negative ions: the direct formation of negative ions by hydrogen atoms rebounding from the surface, and the dissociation of H/sub 2//sup …
Date: July 3, 1989
Creator: Hiskes, J.R. & Karo, A.M.
System: The UNT Digital Library
Information Booklet For FY91/FY92 Capital Project Validation Review (open access)

Information Booklet For FY91/FY92 Capital Project Validation Review

None
Date: May 3, 1989
Creator: unknown
System: The UNT Digital Library