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Interaction of noble-metal fission products with pyrolytic silicon carbide

Description: Fuel particles for the High-Temperature Gas-Cooled Reactor (HTGR) contain layers of pyrolytic carbon and silicon carbide, which act as a miniature pressure vessel and form the primary fission product barrier. Of the many fission products formed during irradiation, the noble metals are of particular interest because they interact significantly with the SiC layer and their concentrations are somewhat higher in the low-enriched uranium fuels currently under consideration. To study fission product-… more
Date: January 1, 1982
Creator: Lauf, R. J. & Braski, D. N.
Partner: UNT Libraries Government Documents Department
open access

What can HELIOS tell us on phase transition of nuclear matter

Description: Transverse energy (E/sub t/) distributions and P/sub t/ spectra of negative particles and photons measured by the HELIOS experiment in 200 GeVN and 60 GeVN oxygen-nucleus reactions are presented. The E/sub t/ distributions are compared to a geometrical parametrization and a Montereverse arrowCarlo calculation, particle spectra to the proton-nucleus reaction case. The comparisons show that yet the results can be understood without assuming quark-gluon plasma formation. A discussion is made based… more
Date: January 1, 1987
Creator: En'yo, H.
Partner: UNT Libraries Government Documents Department
open access

Organic iodine removal from simulated dissolver off-gas streams using silver-exchanged mordenite

Description: The removal of methyl iodide by absorption onto silver mordenite was studied using a simulated off-gas from the fuel dissolution step of a nuclear fuel reprocessing plant. The methyl iodide absorption of silver mordenite was examined for the effects of NO/sub x/, humidity, iodine concentration, filter temperature, and filter pretreatment. The highest iodine loading achieved in these tests has been 34 mg CH/sub 3/I per g of substrate, approximately five times less than the elemental iodine loadi… more
Date: January 1, 1980
Creator: Jubin, R. T.
Partner: UNT Libraries Government Documents Department
open access

Basic studies of a gas-jet-coupled ion source for on-line isotope separation

Description: A hollow-cathode ion source was used in a gas-jet-coupled configuration to produce ion beams of fission products transported to it from a /sup 252/Cf fission source. Solid aerosols of NaCl and Ag were used effectively as activity carriers in the gas-jet system. Flat-plate skimmers provided an effective coupling of the ion source to the gas jet. Ge(Li) spectrometric measurements of the activity deposited on an ion-beam collector relative to that deposited on a pre-skimmer collector were used to … more
Date: January 1, 1980
Creator: Anderl, R. A.; Novick, V. J. & Greenwood, R. C.
Partner: UNT Libraries Government Documents Department
open access

Size effects in aerosol particle interactions: the van der Waals potential and collision rates

Description: Three effects which are explicitly dependent on aerosol particle size are identified and discussed. They are focussed about the particle collision rate and how it relates to the properties of the gas, the particle, and the particle's interaction potential energy which play roles in particle-particle collision rates. By incorporating the conduction electronic free path effect for conductors into the frequency-dependent dielectric constants of silver and graphite, particle size effects in th… more
Date: January 1, 1980
Creator: Marlow, W H
Partner: UNT Libraries Government Documents Department
open access

Muon Spin-Relaxation Measurements of the Fluctuation Modes in Spin-Glass AgMn

Description: Recently reported zero-field ..mu..SR measurements below the spin-glass transition temperature in AgMn (1.6 at. %) show a temperature dependent inhomogenous width. We discuss these data in terms of a model in which the local field undergoes limited-amplitude fluctuations. We find that both very slow (approx. 0.3 ..mu..s/sup -1/) and rapid (approx. 3000 ..mu..s/sup -1/) fluctuations are required.
Date: January 1, 1982
Creator: Heffner, R. H.; Leon, M.; Schillaci, M. E.; MacLaughlin, D. E. & Dodds, S. A.
Partner: UNT Libraries Government Documents Department
open access

Testing site size requirements in chemisorption: experiment and theory

Description: ''Ensemble requirements'' in surface chemistry refer to the number and shape of contiguous empty sites necessary for chemisorption of a particular molecule. Ensemble effects can play a major role in directing the course of surface reactions, leading, for example, to dramatic changes in catalytic selectivity when the active metal component is diluted upon alloying with an inert metal. We will review here fundamental surface science studies that have attempted to probe this site size requirement … more
Date: January 1, 1985
Creator: Campbell, C. T.; Paffett, M. T. & Voter, A. F.
Partner: UNT Libraries Government Documents Department
open access

Organic iodine removal from simulated dissolver off-gas streams using partially exchanged silver mordenite

Description: The removal of methyl iodide by adsorption onto silver mordenite was studied using a simulated off-gas from the fuel dissolution step of a nuclear fuel reprocessing plant. The methyl iodide adsorption of partially exchanged silver mordenite was examined for the effects of NO/sub x/, humidity, filter temperature, and degree of silver exchange. Partially exchanged silver mordenite, in general, achieved significantly higher silver utilizations than the fully exchanged material. Silver utilizations… more
Date: January 1, 1982
Creator: Jubin, R. T.
Partner: UNT Libraries Government Documents Department
open access

Muon Diffusion in Noble Metals

Description: Diffusion-induced muon depolarization was measured in dilute AgGd and AgEr in the temperature range 200 to 700/sup 0/K and have thereby determined the muon diffusion parameters in Ag. The diffusion parameters for ..mu../sup +/ in Cu, Ag, and Au are compared with those of hydrogen. For Ag and Au, the ..mu../sup +/ parameters are similar to those of hydrogen, whereas for Cu, the ..mu../sup +/ parameters are much smaller. Lattice-activated tunneling and over-barrier hopping are investigated with c… more
Date: January 1, 1982
Creator: Schillaci, M. E.; Boekema, C.; Heffner, R. H.; Hutson, R. L.; Leon, M.; Olsen, C. E. et al.
Partner: UNT Libraries Government Documents Department
open access

Super high energy heavy ion collisions

Description: Basic theoretical ideas on a phase transition to a plasma of free quarks and gluons in heavy ion collisions are outlined. First results from experiments with oxygen beams at 14.5 GeV/c/N (BNL), 60 and 200 GeV/c/N (CERN) are discussed. 30 refs., 9 figs.
Date: December 1, 1987
Creator: Geist, W.M.
Partner: UNT Libraries Government Documents Department
open access

A-dependence of inclusive hadron scattering at 100 GeV. Fermilab-Conf-80/47-Exp

Description: An experiment was performed to study the inclusive processes a/sup +/ + A ..-->.. c/sup + -/ + X, where a and c are either ..pi.., K, or p. The nuclear targets used were C, Al, Cu, Ag, and Pb. The Feynman x and p/sub T/ dependence of particle c was studied using the Fermilab Single Arm Spectrometer. In this paper cross sections are presented as a function of x at transverse momenta of 0.3 and 0.5 GeV/c for each target nucleus. The A-dependence is parameterized as sigma/sub A/ = sigma/sub 0/A… more
Date: January 1, 1980
Creator: Brenner, A. E.; Carey, D. C. & Elias, J. E.
Partner: UNT Libraries Government Documents Department
open access

Energy Measurements in Oxygen-Induced Reactions at 60 A GeV and 200 A GeV

Description: In an effort to isolate characteristic features of nucleus-nucleus collisions (e.g., collective phenomena) from those that may be expected on the basis of a linear superposition of nuelceon-nucleon collisions, we will compare measured quantities with calculations that reproduce data from nucleon-induced reactions and that make predictions for nucleus-nucleus reactions. While several models are available for this procedure, none has yet been demonstrated to have clear advantages over the others.… more
Date: January 1, 1988
Creator: Awes, T. C.; Albrecht, R.; Baktash, C.; Beckmann, P.; Berger, F.; Bock, R. et al.
Partner: UNT Libraries Government Documents Department
open access

Irreversibility behavior in Ag-sheathed Bi-based superconducting wires

Description: Irreversibility lines for Ag/(Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub y}(2223) wires prepared through a phase formation- decomposition-recovery (PFDR) process and normal annealing process were determined using both AC susceptibility measurements under DC fields and magnetisation measurements. It was found that flux pinning was enhanced in the PFDR processed samples over the normal processed samples, in particular at temperature above 77 K. The PFDR process results in high mass density, gr… more
Date: April 1, 1992
Creator: Dou, S.X.; Liu, H.K.; Guo, Y.C.; Wang, J.; Jin, X.J.; Hu, Q.Y. (New South Wales Univ., Kensington (Australia)) et al.
Partner: UNT Libraries Government Documents Department
open access

Analysis of polarization properties of shallow metallic gratings by an extended Rayleigh-Fano Theory

Description: Rayleigh-Fano theory has been extended for the purpose of calculating the polarization anomaly of a grating having shallow grooves and finite conductivity. Simple analytic formulas are derived for predicting the position and the appearance of the anomalies. Phenomenological explanations are given to the origin of the anomalies. The validity of our analysis is examined by comparing computed degree of polarization with experimental data obtained in the visible region for Al-, Ag-, and Au-coated b… more
Date: June 1, 1991
Creator: Koike, Masato (Lawrence Berkeley Lab., CA (United States)) & Namioka, Takeshi (Tohoku Univ., Sendai (Japan). Research Inst. for Scientific Measurements)
Partner: UNT Libraries Government Documents Department
open access

Silver isotopic anomalies in iron meteorites: cosmic-ray production and other possible sources

Description: The sources of excess /sup 107/Ag observed in iron meteorites by Kaiser, Kelly, and Wasserburg (1980) are examined, with emphasis on the reactions of cosmic-ray particles with palladium. The cross sections for the production of the silver isotopes from palladium by energetic cosmic-ray particles are evaluated or estimated and used to calculate spallogenic production rates relative to that of /sup 53/Mn from iron. The upper limit for the production rate of excess /sup 107/Ag by galactic-cosmic-r… more
Date: April 18, 1980
Creator: Reedy, R. C.
Partner: UNT Libraries Government Documents Department
open access

Growth and stability of Ag layers on Cu(110)

Description: Combined surface science and high energy ion beam techniques have been used to characterize the composition, structure and thermal stability of Ag layers < 900A thick on Cu(110). A uniform Ag/Cu surface composite is formed for one monolayer coverage. Analysis of its growth with LEED shows that the Ag is initially confined to the (110) troughs and that further deposition results in a Ag(111) layer exhibiting c(2 x 4) symmetry. This surface science determination of Ag coverage is consistent with … more
Date: January 1, 1986
Creator: Taylor, T. N.; Hoffbauer, M. A.; Maggiore, C. J. & Beery, J. G.
Partner: UNT Libraries Government Documents Department
open access

Fractal behavior of single-particle trajectories and isosets in isotropic and anisotropic fluids

Description: Molecular dynamics simulations for a variety of systems in 2 spatial dimensions reveal fractual behavior associated with trajectories and isosets of single particle motion. The fractual dimensions of trajectories and isosets are 2 and 0.5, respectively, irrespective of the nature of the interparticle interaction or thermodynamic state of the system. Recently, we have investigated the fractual behavior of diffusing Ag ions in the superionic phase of Ag/sub 2/S. MD calculations have shown that th… more
Date: August 1, 1985
Creator: Kalia, R.K.; Vashishta, P. & de Leeuw, S.W.
Partner: UNT Libraries Government Documents Department
open access

Compound nucleus studies withy reverse kinematics

Description: Reverse kinematics reactions are used to demonstrate the compound nucleus origin of intermediate mass particles at low energies and the extension of the same mechanism at higher energies. No evidence has appeared in our energy range for liquid-vapor equilibrium or cold fragmentation mechanisms. 11 refs., 12 figs.
Date: June 1, 1985
Creator: Moretto, Luciano G.
Partner: UNT Libraries Government Documents Department
open access

A Modified Pyroelectric Sodium Fluoride Carrier Distillation Medthod For The Spectrographic Analysis Of Impurities In Plutonium

Description: A modification of the pyroelectric sodium fluoride carrier distillation method for analysis of impurities in plutonium metal is described. The metal is dissolved. Plutonium is precipitated and treated with nitric acid. The slurry obtained is dried and ignited. The resultant low density oxide is mixed with sodium fluoride and pressed into a pellet for arcing. Cobalt is used as the internal standard for densitometric using visual comparisons against prepared standards. The procedural modification… more
Date: August 1, 1966
Creator: Schreiber, G. A. & Barrick, C. W.
Partner: UNT Libraries Government Documents Department
open access

Thermal effects of electrically conductive deposits in melter

Description: The radioactive waste processed by the Defense Waste Processing Facility melter at the Savannah river Site contains noble metal fission-products. Operation of waste-glass melters treating commercial power reactor wastes indicates that accumulation of noble metals on melter floors can lead to distortion of electric heating patterns, loss of power, and possible electrode damage. Changes in melter geometry have been developed in Japan and Germany to minimize these effects. The two existing melters… more
Date: January 1, 1992
Creator: Choi, I.G.; Bickford, D.F. & Carter, J.T.
Partner: UNT Libraries Government Documents Department
open access

Low p/sub T/ inclusive production in hadron-nucleus collisions. [100 GeV/c]

Description: New experimental results on the A dependence of inclusive hadron scattering are described with emphasis on the projectile fragmentation region. The experiment measured h + A ..--&gt;.. h&#x27; + x, where h was ..pi../sup +/, K/sup +/, or p; h&#x27; was ..pi../sup + -/, K/sup + -/, or p; and A, the nuclear target, was C, Al, Cu, Ag, or Pb. The experimental apparatus consisted of the Fermilab M6E beam line and the Single Arm Spectrometer Facility. An incident beam of 100 GeV/c was used; the produ… more
Date: January 1, 1980
Creator: Barton, D S
Partner: UNT Libraries Government Documents Department
open access

Application Experience and Field Performance of Silvered Polymer Reflectors

Description: The solar-weighted hemispheric reflectance of unweathered silvered acrylic mirrors exceeds 92%, and specular reflectance into a 4- milliradian, full-cone acceptance angle is greater than 90%. Comparison of outdoor and accelerated tests suggests that the protected silver can resist corrosion for the five-year life that is the current goal. An installation of parabolic troughs has been cleaned monthly for two years, and reflectance is regularly returned to within a few percent of the initial refl… more
Date: April 1, 1991
Creator: Schissel, P.; Jorgensen, G. & Pitts, R.
Partner: UNT Libraries Government Documents Department
open access

Particle angular distributions and gamma-ray multiplicities as experimental probes for angular-momentum fluctuations

Description: The sequential emission of /sup 4/He is demonstrated in the reaction Ho + Ta and the /sup 4/He angular distribution is used to test the rigid rotation limit in the reaction Ho + Ag. A more refined analysis of the dependence of continuum ..gamma..-ray multiplicities upon Q-value and gamma ray energy shows that reasonable agreement with the statistical model is obtained if one assumes the presence of low energy aligned dipole transitions in the reactions Ho, Yb, Sm, Ag + Ho. Sequential fission an… more
Date: March 1, 1982
Creator: Moretto, Luciano G.
Partner: UNT Libraries Government Documents Department
open access

Processing and properties of silver-clad Tl-Ba-Ca-Cu-O wires and tapes

Description: TlBa{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} and Tl{sub 2}Ba{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} powders were synthesized, loaded into Ag tubes, and worked into wires and tapes by drawing and rolling. All processing outside of furnaces was in a dry-N{sub 2} glovebox. All heat treatments were performed in O{sub 2}. The Ag-clad wires fabricated from these powders exhibited onset of superconductivity at {approx}118 K and critical current densities at 77K of 2{times}10{sup 3} to 4{times}10{sup 3} A/cm{sup 2}. more
Date: March 1, 1992
Creator: Goretta, K.C.; Wu, C.T.; Lanagan, M.T.; Boling, M.A.; Shi, D.; Miller, D.J. et al.
Partner: UNT Libraries Government Documents Department
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