83 Matching Results

Search Results

Advanced search parameters have been applied.
in subjects: "Silicon Oxides"  
Results: 1 - 24 next
open access

[The physics of pattern formation of liquid interfaces]

Description: Energy consumption in fabrication of materials for all applications is process dependent. Improvements in the ability to process materials are of great importance to the DOE mission. This project addresses basic science questions related to the processing of materials and is aimed at understanding growth of interfaces and evolution of patterns on interfaces, both macroscopic and microscopic. Three laboratory experiments are proposed: A study of the changes in patterns available to the growth of… more
Date: January 1, 1993
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

High resolution interface nanochemistry and structure

Description: A summary is given of results on nanospectroscopy etc. during the previous three years, divided into the following subsections: development of methods and instrumentation for interface/boundary chemical analysis, interface and boundary structure in ceramic matrix composites, quantitative composition measurements of thin films and inclusions, theoretical calculations for electron energy loss near edge fine structure and grain boundary structure, and small probe radiation effects in ceramics. Mat… more
Date: January 1, 1993
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Reduced optical transmission of SiO[sub 2] fibers used in controlled fusion diagnostics

Description: We have subjected a silica core fiber optic cable to 4 years of low-level neutron and gamma radiation from Princeton's TFTR controlled fusion experiment The accumulated dose was 200 Gy. As a result of the radiation, we have measured increased attenuations of 100--300 db/km in the visible part of the spectrum, and a decrease of the numerical aperture. An attempt to decrease this damage by photobleaching failed. We argue that this failure is not unexpected, since the rate of damage is so slow and… more
Date: February 1, 1993
Creator: Ramsey, A.T.; Adler, H.G. & Hill, K.W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Support effects studied on model supported catalysts

Description: Composition and structure of oxide support materials can change the catalytic behavior of metal and oxide catalysts. Model catalysts are being studied in which the active phase is deposited on flat oxide substrates, with emphasis on metals catalysis for automotive emissions control and acidity in supported oxides. Research is reported in the following areas: particle-size effects, support effects on ZnO and zirconia, support effects on ceria, supported oxides, and low energy ion scattering (no … more
Date: February 1, 1993
Creator: Gorte, R.J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A literature review of surface alteration layer effects on waste glass behavior

Description: When in contact with an aqueous solution, nuclear waste glass is subject to a chemical attack that results in progressive alteration. During tills alteration, constituent elements of the glass pass into the solution; elements initially in solution diffuse into, or are adsorbed onto, the solid; and new phases appear. This results in the formation of surface layers on the reacted glass. The glass corrosion and radionuclide release can be better understood by investigating these surface layer effe… more
Date: January 1, 1993
Creator: Feng, X.; Cunnane, J.C. & Bates, J.K.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Catalytic hydrocarbon reactions over supported metals

Description: During the past year we have completed our characterization of the factors that control the structure of fully oxidized W and Mo on silica and have established that support hydroxyl groups play a central role in dispersing and attaching cations to the support oxide. Work with M[sub 2](CO)[sub 4]Cp[sub 2](M[sub 2]=MoMo, WW, MoW) system has been very encouraging and continues to support the notion that it may be possible to control the structure of adsorbed catalysts (in this case generate metal … more
Date: March 29, 1993
Creator: Ekerdt, J. G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

NMR measurement of pore structure

Description: An attempt was made to pursue [sup 129]Xe NMR as a pore measurement technique. Samples studied were synthetic imogolite (tubular aluminosilicate with gibbsite structure), sodium Y-zeolite, and an aerogel and a xerogel. Gases used were normal Xe, [sup 13]CO[sub 2], and [sup 15]N[sub 2]. Although a completely general NMR technique for measuring pore size distributions may not be possible, information about molecular motion and interactions can be obtained, because NMR is sensitive to short range … more
Date: May 31, 1993
Creator: Earl, W.L. (Los Alamos National Lab., NM (United States)); Kim, Yong-Wah (Los Alamos National Lab., NM (United States) New Mexico Univ., Albuquerque, NM (United States). Center for Microengineered Ceramics) & Smith, D.M. (New Mexico Univ., Albuquerque, NM (United States). Center for Microengineered Ceramics)
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Effect of composition and temperature on viscosity and electrical conductivity of borosilicate glasses for Hanford nuclear waste immobilization

Description: Viscosity and electrical conductivity of 79 simulated borosilicate glasses in the expected range of compositions to be produced in the Hanford Waste Vitrification Plant were measured within the temperature span from 950 to 1250[degree]C. The nine major oxide components were SiO[sub 2], B[sub 2]O[sub 3], Li[sub 2]O, Na[sub 2]O, CaO, MgO, Fe[sub 2]O[sub 3], Al[sub 2]O[sub 3], and ZrO[sub 2]. The test compositions were generated statistically. The data were fitted by Fulcher and Arrhenius equation… more
Date: April 1, 1993
Creator: Hrma, P.; Piepel, G. F.; Smith, D. E.; Redgate, P. E. & Schweiger, M. J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Charge trapping and breakdown in N{sub 2}O oxides

Description: Nitrided gate oxides have been fabricated by furnace oxidation in N{sub 2}O with and without prior oxidation in O{sub 2}. SIMS nitrogen profiles show a sharp peak at the Si-insulator interface for both processes. Improved breakdown characteristics and reduced oxide damage after irradiation and charge injection are obtained.
Date: December 1, 1993
Creator: Saks, N. S.; Ma, D. I. & Fleetwood, D. M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

The formation of silica, alumina and zirconia supported high surface area monometallic and bimetallic catalysts. Progress report

Description: During the current granting period, 12/01/92--11/30/93, studies have progressed along four fronts: (1) Preparation of high surface area Pt/SiO{sub 2} catalysts; (2) preparation of high surface area Pt/Al{sub 2}O{sub 3} catalysts; (3) preparation of high surface area promoted zirconia superacid catalysts and, (4) stabilization and sintering of porous Pt/SiO{sub 2} catalysts. In addition to these current studies a major review article on previously funded DOE research has been completed and will … more
Date: December 1, 1993
Creator: Gonzalez, R. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Sol-gel derived silica/siloxane composite materials: The effect of loading level and catalyst activity on silica domain formation

Description: Currently, the production of in situ reinforcement in polymeric systems by sol-gel methods is undergoing rapid development. However, understanding of synthesis/structure/property relationships is still lacking. In order to produce sol-gel derived composite materials with sufficient mechanical properties for commercial applications, this deficit of information must be addressed. We have completed a detailed investigation of in situ silica growth in polydimethylsiloxane (PDMS)/tetraethylorthosili… more
Date: November 1, 1993
Creator: Black, E. P.; Ulibarri, T. A.; Beaucage, G.; Schaefer, D. W.; Assink, R. A.; Bergstrom, D. F. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Pressure-induced amorphizations of silica analogues: A probe of the relationship between order and disorder. Progress report, August 1, 1992--July 31, 1993

Description: Purpose of these of high pressure investigations is to determine the relationship between order and disorder in amorphous materials using high pressure techniques were used. High pressure x-ray diffraction, electron transmission microscopy, and Raman scattering. Cornell High Energy Synchrotron Source (CHESS) at Ithaca was used to measure x-ray diffraction patterns using Energy-Dispersive X-ray Diffraction. It was shown that the structural ordering in pressure-amorphized solids can be described … more
Date: February 1, 1993
Creator: Hammack, W. S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

In-situ TEM crystallization of anorthite-glass films on {alpha}-Al{sub 2}O{sub 3}

Description: Anorthite-glass films have been grown by pulsed-laser deposition on single-crystal {alpha}-Al{sub 2}O{sub 3} substrates which were pre-thinned to electron transparency. The glass films were crystallized in the transmission electron microscope (TEM), which allowed direct observation and video-recording of the crystallization process. Crystallization of these films in the TEM resulted in the formation of hexagonal and orthorhombic anorthite. The orthorhombic phase was the predominant product of g… more
Date: December 31, 1993
Creator: Mallamaci, M. P.; Carter, C. B. & Bentley, J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Inert strength of pristine silica glass fibers

Description: Silica glass fibers have been produced and tested under ultra high vacuum (UHV) conditions to investigate the inert strength of pristine fibers in absence of reactive agents. Analysis of the coefficient of variation in diameter ({upsilon}{sub d}) vs the coefficient of variation of breaking strength ({upsilon}{sub {sigma}}) does not adequately explain the variation of breaking stress. Distribution of fiber tensile strength data suggests that the inert strength of such fibers is not single valued… more
Date: November 1, 1993
Creator: Smith, W. L. & Michalske, T. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Surface chemistry of boron-doped SiO{sub 2} CVD: Enhanced uptake of tetraethyl orthosilicate by hydroxyl groups bonded to boron

Description: Insight into how dopants can enhance deposition rates has been obtained by comparing reactivities of tetraethyl orthosilicate (TEOS, Si(OCH{sub 2}CH{sub 3}){sub 4}) with silanol and boranol groups on SiO{sub 2}. This comparison is relevant for boron-doped SiO{sub 2} film growth from TEOS and trimethyl borate (TMB, B(OCH{sub 3}){sub 3}) sources since boranols and silanols are expected to be present on surface during the (CVD). A silica substrate having coadsorbed deuterated silanols (SIOD) and b… more
Date: December 31, 1993
Creator: Bartram, M. E. & Moffat, H. K.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Development of a catalyst for conversion of syngas-derived materials to isobutylene. Technical progress report No. 6, July 1, 1992--September 30, 1992

Description: Goal is to develop a catalyst and technology that will produce iC{sub 4}{double_bond} directly from coal-derived syngas and that is capable of using a lower H{sub 2}/CO ratio (0.5 to 1.0). This report covers the testing of various zirconia (ZrO{sub 2}) based catalyst systems designed to examine effects of catalyst preparation and process variables, especially feed additives. Testing sol-gel ZrO{sub 2} catalysts calcined at 475 C instead of 500 C increases the isobutene yield. Supporting zirconi… more
Date: September 10, 1993
Creator: Gajda, G. J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

High resolution interface nanochemistry and structure

Description: A summary is given of results on nanospectroscopy etc. during the previous three years, divided into the following subsections: development of methods and instrumentation for interface/boundary chemical analysis, interface and boundary structure in ceramic matrix composites, quantitative composition measurements of thin films and inclusions, theoretical calculations for electron energy loss near edge fine structure and grain boundary structure, and small probe radiation effects in ceramics. Mat… more
Date: March 1, 1993
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Silica Membranes for Hydrogen Separation in Coal Gas Processing. Final Report, January 1993

Description: The general objective of this project was to synthesize permselective membranes suitable for hydrogen separation from coal gas. The specific objectives were: (i) to synthesize membranes by chemical vapor deposition (CVD) of SiO{sub 2} or other oxides on porous support tubes, (ii) characterize the membranes by permeation measurements of various gases and by electron microscopy, and (iii) obtain information about the mechanism and kinetics Of SiO{sub 2} deposition, and model the process of membra… more
Date: March 1, 1993
Creator: Gavalas, G. R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Support effects studied on model supported catalysts. Progress report

Description: Composition and structure of oxide support materials can change the catalytic behavior of metal and oxide catalysts. Model catalysts are being studied in which the active phase is deposited on flat oxide substrates, with emphasis on metals catalysis for automotive emissions control and acidity in supported oxides. Research is reported in the following areas: particle-size effects, support effects on ZnO and zirconia, support effects on ceria, supported oxides, and low energy ion scattering (no … more
Date: February 1, 1993
Creator: Gorte, R. J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

[The physics of pattern formation of liquid interfaces]

Description: Energy consumption in fabrication of materials for all applications is process dependent. Improvements in the ability to process materials are of great importance to the DOE mission. This project addresses basic science questions related to the processing of materials and is aimed at understanding growth of interfaces and evolution of patterns on interfaces, both macroscopic and microscopic. Three laboratory experiments are proposed: A study of the changes in patterns available to the growth of… more
Date: May 1, 1993
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Selective methane oxidation over promoted oxide catalysts. Quarterly technical progress report, September 8, 1992--November 30, 1992

Description: Support effects on catalytic reactions, especially of highly exothermic oxidation reactions, can be very significant. Since we had shown that a MoO{sub 3}/SiO{sub 2} catalyst, especially when used in a double bed configuration with a Sr/La{sub 2}O{sub 3} catalyst, can selectively oxidize methane to formaldehyde, the role of the SiO{sub 2} support was investigated. Therefore, partial oxidation of methane by oxygen to form formaldehyde, carbon oxides, and C{sub 2} products (ethane and ethene) has… more
Date: January 1, 1993
Creator: Klier, K.; Herman, R. G.; Sun, Q. & Sarkany, J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Transient studies of low temperature catalysts for methane conversion. Quarterly technical progress report, January 1, 1993--March 30, 1993

Description: This report summarizes studies conducted during the past quarter on the partial oxidation of methane on the following catalysts: vanadium phosphate, unsupported and supported on silica, and on the silica (SiO{sub 2}) support. It was found that the unsupported vanadium phosphate catalyst exhibits some selectivity towards formaldehyde at relatively low methane conversions (up to 5% conversion). The selectivity decreases even further on the silica supported VPO catalyst without a significant incre… more
Date: July 1, 1993
Creator: Wolf, E. E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

High octane ethers from synthesis gas-derived alcohols. Quarterly technical progress report, October--December 1992, Revision 1

Description: The objective of the proposed research is to synthesize high octane ethers, primarily methyl isobutyl ether (MIBE) and methyl tertiary butyl ether (MTBE) directly from H{sub 2}/CO/CO{sub 2} coal-derived synthesis gas via alcohol mixtures that are rich in methanol and 2-methyl-l-propanol (isobutanol). The overall scheme involves gasification of coal, purification and shifting of the synthesis gas, higher alcohol synthesis, and direct synthesis of ethers. The testing of strongly acidic catalysts … more
Date: April 1, 1993
Creator: Klier, Kamil; Herman, Richard G.; Johansson, Marie A. & Feeley, Owen C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Performance of the Amorphous Materials Diffractometer ``GLAD`` at IPNS

Description: The Glass, Liquids, and Amorphous Materials Diffractometer (GLAD) at IPNS has now been commissioned and the first scientific measurements have been carried out. Details of the performance of this inswment, including background, calibration, resolution, data rate, data quality, and data reduction and analysis will be discussed.
Date: July 1, 1993
Creator: Ellison, A. J. G.; Volin, K. J.; Price, D. L. & Crawford, R. K.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
Back to Top of Screen