18 Matching Results

Search Results

Advanced search parameters have been applied.
in subjects: "Silicon Oxides"  
Results: 1 - 18
open access

Damage to fused silica windows while under simultaneous exposure to flowing solvents and laser radiation and 308nm

Description: This paper reports the results of a study to determine the degrading effects of flowing dye solvents on the laser damage threshold of fused-silica windows at 308nm. Thresholds were measured at the SiO/sub 2/solvent interface in a test cell. Bare SiO/sub 2/ tested in air at 308nm (20ns) typically exhibits a threshold ranging from 4 to 10 Jcm/sup 2/; with the solvent cyclohexane in contact, a threshold as low as 0.3 Jcm/sup 2/ was measured. The damage data indicate that window lifetime (number of… more
Date: January 1, 1987
Creator: Mauro, B. R.; Foltyn, S. R. & Sanders, V. E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Pourbaix diagram for the prediction of waste glass durability in geologic environments

Description: Dissolution of nuclear waste glass occurs by corrosion mechanisms similar to those of metallurgical and mineralogic systems albeit on different time scales. The effects of imposed pH and oxidation potential (Eh) conditions existing in natural environments on metals and minerals have been quantitatively and phenomenologically described in compendiums of Pourbaix (pH-potential) diagrams. Construction of Pourbaix diagrams to quantify the response of nuclear waste glasses to repository specific pH … more
Date: January 1, 1987
Creator: Jantzen, Carol M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Si-SiO/sub 2/ interfaces: A HRTEM (High Resolution Transmission Electron Microscopy) study

Description: A High Resolution Transmission Electron Microscopy (HRTEM) study of the Si-SiO/sub 2/ interfaces is reported here. The study has been carried out on the thermal oxidation of (1) Si and (2) Ge implanted Si. Evolution of the Si-SiO/sub 2/ interface with oxide thickness and the presence of small amounts of Ge, i.e., one mono-layer at the interface and its influence on the oxidation kinetics is discussed.
Date: January 1, 1987
Creator: Ravindra, N.M.; Fathy, D.; Holland, O.W. & Narayan, J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Integrated oxidation-glass formation process for waste sodium disposal

Description: For permanent disposal of the large quantities of mildly contaminated waste liquid metals (primarily sodium) used as coolants in nuclear reactors, and currently stored at different DOE sites, it is necessary to convert the metal to a stable and environmentally acceptable disposable form at minimum cost. Work on air oxidation of sodium done by Mine Safety and Appliances, Inc. (MSA) in 1980 showed the feasibility of converting the metal to its oxides. This study investigates the development of an… more
Date: January 1, 1987
Creator: Rajan, J.B.; Kumar, R. & Vissers, D.R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Ion mixing of Ti/C and Fe/C bilayers

Description: Bilayer samples of Ti/C and Fe/C have been ion beam mixed with 400-keV Xe ions to a dose of 1 x 10/sup 16/ ions/cm/sup 2/. Mixing experiments were performed at 77, 300, 573, and 723/sup 0/K. The transition between the temperature-independent and temperature-dependent mixing occurred between 300 and 573/sup 0/K in Fe/C samples and between 573 and 723/sup 0/K in Ti/C sample. In the temperature-independent mixing regime, mixing is reasonably well explained by a thermodynamic model of ion mixing wh… more
Date: June 1, 1987
Creator: Nastasi, M.; Tesmer, J.R. & Hirvonen, J.P.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Probing medium-range order in chalcogenide glasses by neutron scattering and optical spectroscopy. [GeSe/sub 2/, SiSe/sub 2/, P/sub 50/-Se/sub 50/, SiO/sub 2/]

Description: The use of neutron diffraction, neutron inelastic scattering, and optical spectroscopy to probe the nature of the medium-range order (MRO) in amorphous materials is discussed with reference to chalcogenides of GeSe/sub 2/, SiSe/sub 2/, and also P/sub 50/Se/sub 50/, and SiO/sub 2/ glasses. While none of these probes provides a unique determination of the MRO, the use of information obtained from the three techniques, supplemented by numerical calculations based on specific structural models, can… more
Date: July 1, 1987
Creator: Price, D.L.; Susman, S. & Wright, A.C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Radiation-induced transient attenuation of optical fibers at 800 and 1300 nm

Description: Radiation-induced absorption in optical fibers has been a subject of considerable interest throughout the world. As availability and applications of fibers have evolved from ''first window'' systems operating near 850 nm to ''second window'' systems near 1300 nm, interest in wavelength dependence of radiation effects in optical fibers has similarly evolved. The present work summarizes second-window, radiation-induced transient absorption measurements in optical fibers for times shorter than 5 .… more
Date: January 1, 1987
Creator: Looney, L.D. & Lyons, P.B.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

A chemical precursor to optical damage. Studies by laser ionization mass spectrometry

Description: Mass spectrometry has been used in conjunction with Nomarski microscopy to characterize the initiation of optical damage in selected commercial optics. For a sample with an Al/sub 2/O/sub 3//SiO/sub 2/ multilayer coating (351 nm) on a Si substrate, our results suggest layer by layer removal of the coating material with low-fluence irradiation at 1.06 mu. In addition, carbon impurities were observed in the low-damage threshold sample. For the Sc/sub 2/O/sub 3//SiO/sub 2/ multilayer coated (351 n… more
Date: January 1, 1987
Creator: Nogar, N.S. & Estler, R.C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

SPECOMP calculations of radiation damage in compounds. [V-15Cr-5Ti]

Description: A new computer code SPECOMP has been developed to calculate displacement damage for compound materials. The code uses primary recoil atom energy distributions from the SPECTER code and thus requires no access to nuclear data bases. For each combination of recoil and matrix atom, the code determines the secondary displacement functions and integrates over the recoil energy distributions. The net displacements for a compound is then the weighted sum of all combinations of atoms in the compound. C… more
Date: January 1, 1987
Creator: Greenwood, L.R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Mechanism of surface enrichment and adhesion of coal combustion particulates

Description: Following is an updated list of accomplishments: Design of an experimental set up and development of experimental techniques for study of the adsorption and desorption of alkali on coal ash and potential additive particles. Development of techniques for quantitative and qualitative characterization of alkali distribution in small additive particles using Scanning Auger Spectroscopy. Completion of a set of adsorption experiments for measuring the rate, capacity and adsorption characteristics of … more
Date: January 1, 1987
Creator: Shadman, F.; Peterson, T.W.; Wendt, J.O.L.; Punjak, W.A. & Rizeq, G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Chemical behaviour of geothermal silica after precipitation from geothermal fluids with inorganic flocculating agents at the Hawaii Geothermal Project Well-A (HGP-A)

Description: The report summarizes the results of experiments dealing with the problem of removal of waste-silica from spent fluids at the experimental power generating facility in the Puna District of the island of Hawaii. Geothermal discharges from HGP-A represent a mixture of meteoric and seawaters which has reacted at depth with basalts from the Kilauea East Rift Zone under high pressure and temperature. After separation of the steam phase of the geothermal fluid from the liquid phase and a final flashi… more
Date: January 1, 1987
Creator: De Carlo, E.H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Cherenkov and transition radiation diagnostics for high energy free-electron lasers

Description: Electron Beam diagnostics based on imaging techniques using Cherenkov conversion screens and intensified video cameras should be adaptable to the developing high-energy free-electron lasers (FEL) driven by radio frequency powered linear accelerators. The high beam energies (60-150 MeV) and the peak currents (100s of amps) anticipated should also make optical transition radiation intensities sufficient for these techniques. The distinctive features of the two light generation mechanisms will be … more
Date: January 1, 1987
Creator: Lumpkin, A. H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Whisker reinforced structural ceramics: Progress in the VLS growth and use of long silicon carbide whiskers. [Vapor-liquid-solid]

Description: A VLS (vapor-liquid-solid) whisker growth process, optimized for the production of short (approx.10 mm lengths) SiC whiskers, was modified to produce greater than or equal to 25 mm long whiskers. In conjunction with this modification, a plan was developed for incorporating an artificial-intelligence system to enhance the whisker growth process. An oriented whisker ribbon was produced from the long whiskers, as a step toward the development of a staple whisker yarn.
Date: January 1, 1987
Creator: Gac, F.D.; Shalek, P.D.; Parkinson, W.J.; Edwards, C. & Price, J.B.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

The effect of additives on the reactivity of palladium surfaces for the chemisorption and hydrogenation of carbon monoxide: A surface science and catalytic study. [LaMO/sub 3/(M = Cr, Mn, Fe, Co, Rh)]

Description: This research studied the role of surface additives on the catalytic activity and chemisorptive properties of Pd single crystals and foils. Effects of Na, K, Si, P, S, and Cl on the bonding of CO and H and on the cyclotrimerization of acetylene on the (111), (100) and (110) faces of Pd were investigated in addition to role of TiO/sub 2/ and SiO/sub 2/ overlayers deposited on Pd foils in the CO hydrogenation reaction. On Pd, only in the presence of oxide overlayers, are methane or methanol forme… more
Date: June 1, 1987
Creator: Rucker, T.G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Mechanism of surface enrichment and adhesion of coal combustion particulates. Second quarterly report, September 1987

Description: Following is an updated list of accomplishments: Design of an experimental set up and development of experimental techniques for study of the adsorption and desorption of alkali on coal ash and potential additive particles. Development of techniques for quantitative and qualitative characterization of alkali distribution in small additive particles using Scanning Auger Spectroscopy. Completion of a set of adsorption experiments for measuring the rate, capacity and adsorption characteristics of … more
Date: December 31, 1987
Creator: Shadman, F.; Peterson, T. W.; Wendt, J. O. L.; Punjak, W. A. & Rizeq, G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Energy loss and scattering of subexcitation electrons in SiO/sub 2/

Description: For electrons with energies below the band gap energy of approx. 9 eV in SiO/sub 2/, energy loss or gain occurs through phonon emission or absorption. Coupling to the longitudinal optical (LO) modes has been considered by several workers in connection with ''electron-runaway'' and subsequent ''breakdown'' when high electric fields are applied to this insulator. The important role played by acoustic phonon modes in predicting the breakdown field in SiO/sub 2/ was recently discussed by Fischetti … more
Date: January 1, 1987
Creator: Ashley, J.C.; Ritchie, R.H. & Crawford, O.H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

KLM's Boric Acid Reclamation System (BARS): An update

Description: KLM Technologies has implemented its Department of Energy Phase II Small Business Innovative Research (SBIR) demonstration program for a radioactive waste Boric Acid Reclamation System (BARS). Preliminary performance indicates enhanced treatment by the BARS technique over state of the art process methods for selective removal of silica and other impurities from borated water matrices. At optimal system recovery of 96 to 97%, BARS removes nominal levels of boric acid while achieving significant … more
Date: February 1, 1987
Creator: Schuelke, Donald; Kniazewycz, B. George; Markind, Joseph; Brossart, Mark A. & Choi, Richard C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Rock Matrix and Fracture Analysis of Flow in Western Tight Gas Sands: Annual Report, Phase 3

Description: Tight gas sands are a vast future source of natural gas. These sands are characterized as having very low porosity and permeability. The main resource development problem is efficiently extracting the gas from the reservoir. Future production depends on a combination of gas price and technological advances. Gas production can be enhanced by fracturing. Studies have shown that many aspects of fracture design and gas production are influenced by properties of the rock matrix. Computer models for … more
Date: December 1, 1987
Creator: Dandge, V.; Graham, M.; Gonzales, B. & Coker, D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
Back to Top of Screen