189 Matching Results

Search Results

Advanced search parameters have been applied.

in subjects: "Sol-Gel Process"

open access

High-level waste program progress report, April 1, 1980-June 30, 1980

The highlights of this report are on: waste management analysis for nuclear fuel cycles; fixation of waste in concrete; study of ceramic and cermet waste forms; alternative high-level waste forms development; and high-level waste container development.

Date: August 1, 1980

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Preparation of synthetic standard minerals

A number of techniques for synthetic mineral preparations have been examined. These techniques include hot-pressing in graphite dies at moderate pressures, high-pressure, high-temperature synthesis in a piston and cylinder apparatus, isostatic pressing under helium gas pressures, hydrous mineral preparations using water as the pressure medium, explosion-generated shock waves, and radiofrequency heating. Minerals suitable for equation-of-state studies (three-inch, high-density discs), for thermo… more

Date: January 1, 1978

Creator: Herrick, C .C.; Bustamante, S. J.; Charls, R. W.; Cowan, R. E.; Hakkila, E. A.; Hull, D. E. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Environmentally Benign Stab Detonators

The coupling of energetic metallic multilayers (a.k.a. flash metal) with energetic sol-gel synthesis and processing is an entirely new approach to forming energetic devices for several DoD and DOE needs. They are also practical and commercially viable manufacturing techniques. Improved occupational safety and health, performance, reliability, reproducibility, and environmentally acceptable processing can be achieved using these methodologies and materials. The development and fielding of this t… more

Date: July 7, 2006

Creator: Gash, A. E.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

High-level waste program progress report, January 1, 1980-March 31, 1980

FUETAP concretes cured at 100/sup 0/C and 0.1 or 0.6 MPa had essentially the same physical properties as those cured at higher temperatures and pressures. Standard specimens containing high concentrations of /sup 244/Cm showed little gasification after 1 month. The large (23-cm ID) spray calciner has been completed and is operating satisfactorily. Construction was completed on a sphere-forming system capable of producing 100-g batches of Synroc spheres by internal gelation, and several runs wer… more

Date: May 1, 1980

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Transient stress evolution and crystallization in laser-irradiated amorphous titania sol-gel films

Amorphous TiO{sub 2} sol-gel films are irreversibly transformed to a crystalline anatase phase when heated to temperatures in excess of 575 K or subjected to intense pulsed or CW laser irradiation. The laser-induced transformation is initiated as a result of impurity absorption and subsequent heating, and results in densification and relative changes in compressive stress of the film. Isothermally annealed films exhibit a decrease in compressive stress as crystallization proceeds while an incre… more

Date: October 1, 1991

Creator: Exarhos, G.J.; Hess, N.J. (Pacific Northwest Lab., Richland, WA (United States)) & Wood, S. (Washington State Univ., Pullman, WA (United States). Dept. of Physics)

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Fabrication, properties, and tritium recovery from solid breeder materials

The breeding blanket is a key component of the fusion reactor because it directly involves tritium breeding and energy extraction, both of which are critical to development of fusion power. The lithium ceramics continue to show promise as candidate breeder materials. This promise was recognized by the International Thermonuclear Experimental Reactor (ITER) design team in its selection of ceramics as the first option for the ITER breeder material. Blanket design studies have indicated properties… more

Date: January 1, 1991

Creator: Johnson, C.E. (Argonne National Lab., IL (USA)); Kondo, T. (Japan Atomic Energy Research Inst., Tokyo (Japan)); Roux, N. (CEA Centre d'Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France)); Tanaka, S. (Tokyo Univ. (Japan)) & Vollath, D. (Kernforschungszentrum Karlsruhe GmbH (Germany, F.R.))

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Consolidated Fuel-Reprocessing Program. Progress report, April 1 to June 30, 1983

All research and development on fuel reprocessing in the United States is managed under the Consolidated Fuel Reprocessing Program. Technical progress is reported in overview fashion. Conceptual studies for the proposed Breeder Reprocessing Engineering Test (BRET) have continued. Studies to date have confirmed the feasibility of modifying an existing DOE facility at Hanford, Washington. A study to measure the extent of plutonium polymerization during steam-jet transfers of nitric acid solutions… more

Date: August 1, 1983

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Oak Ridge National Laboratory materials highlights

The metallic materials discussed briefly in this report are nickel aluminides, nickel-iron aluminides, Fe{sub 3}-Al-based iron aluminides, and advanced austenitic alloys for coal utilization applications. Whisker-reinforced ceramic composites, toughened zirconia ceramics, fiber reinforced composite hot-gas filters, and titanium diboride are all discussed. The sol-gel process for the fabrication of high-yield oxide varistors is presented briefly. The use of zirconia-bonded zirconia for fiber ins… more

Date: December 1, 1990

Creator: Weir, J.R. (Oak Ridge National Lab., TN (USA)) & Daghir, R. (Pennsylvania State Univ., University Park, PA (USA))

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Spectroscopic probes of the structure of hydrous uranium oxide precursors to UO sub 2 ceramic fuel

Fourier Transform infrared spectroscopy, x-ray powder diffraction and thermal analysis show that one example of ammonium diuranate'' observed as an intermediate in the U(VI) sol-gel process is a layered hydrous uranium oxide with a proposed structural formula of (NH){sub 4}{sub 2}((UO{sub 2}){sub 8}O{sub 4}(OH){sub 10}){center dot}8H{sub 2}O, an ammonium ion intercalate. Examples of polyamine intercalation compounds hydrous uranium oxide are also given.

Date: January 1, 1989

Creator: Thompson, M.C.; King, C.M. (Westinghouse Savannah River Co., Aiken, SC (United States)) & King, R.B. (Georgia Univ., Athens, GA (United States). Dept. of Chemistry)

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Dissolution of mixed oxide fuel as a function of fabrication variables

Dissolution properties of mechanically blended mixed oxide fuel were very dependent on the six fuel fabrication variables studied. Fuel sintering temperature, source of PuO/sub 2/ and PuO/sub 2/ content of the fuel had major effects: (1) as the sintering temperature was increased from 1400 to 1700/sup 0/C, pellet dissolution was more complete; (2) pellets made from burned metal derived PuO/sub 2/ were more completely dissolved than pellets made from calcined nitrate derived PuO/sub 2/ which in … more

Date: August 1, 1979

Creator: Lerch, R.E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

New insights into uranium (VI) sol-gel processing

Nuclear Magnetic Resonance (NMR) investigations on the Oak Ridge National Laboratory process for sol-gel synthesis of microspherical nuclear fuel (UO{sub 2}), has been extremely useful in sorting out the chemical mechanism in the sol-gel steps. {sup 13}C, {sup 15}N, and {sup 1}H NMR studies on the HMTA gelation agent (Hexamethylene tetramine, C{sub 6}H{sub 12}N{sub 4}) has revealed near quantitative stability of this adamantane-like compound in the sol-gel process, contrary to its historical ro… more

Date: January 1, 1990

Creator: King, C.M.; Thompson, M.C.; Buchanan, B.R. (Westinghouse Savannah River Co., Aiken, SC (USA)); King, R.B. (Georgia Univ., Athens, GA (USA). Dept. of Chemistry) & Garber, A.R. (South Carolina Univ., Columbia, SC (USA). Dept. of Chemistry)

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Dip coating of sol-gels

Dip coating is the primary means of depositing sol-gel films for precision optical coatings. Sols are typically multicomponent systems consisting of an inorganic phase dispersed in a solvent mixture, with each component differing in volatility and surface tension. This, together with slow coating speeds (<1cm/s), makes analysis of the coating process complicated; unlike most high-speed coating methods, solvent evaporation, evolving rheology, and surface tension gradients alter significantly the… more

Date: January 1, 1991

Creator: Schunk, P. R.; Hurd, A. J. & Brinker, C. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Aerogels Derived From Multifunctional Organic Monomers

Traditional inorganic aerogels are mad via the hydrolysis and condensation of metal alkoxides. Recently, we reported the synthesis of organic aerogels based upon the aqueous polycondensation of (1) resorcinol with formaldehyde and (2) melamine with formaldehyde. The former materials can also be pyrolyzed in an inert atmosphere to form vitreous carbon aerogels. In both the inorganic and organic systems, the structure and properties of the dried aerogel are dictated by polymerization conditions. … more

Date: September 1, 1991

Creator: Pekala, R. W.; Alviso, C. T.; Kong, F. M. & Hulsey, S. S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Optical and environmentally protective coatings for potassium dihydrogen phosphate (KDP) harmonic converter crystals

Potassium dihydrogen phosphate (KDP) crystals have been used as harmonic converters on the Nova laser at LLNL for over six years. All crystals were coated with a single layer, quarterwave AR coating of porous silica with a refractive index of 1.22. This was prepared by a sol-gel process and was applied from a colloidal suspension by spin coating at room temperature. A few crystals were also coated with a methyl silicone coating prior to the application of the AR coating for environmental protec… more

Date: June 24, 1991

Creator: Thomas, I. M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Transparent ultralow-density silica aerogels prepared by a two-step sol-gel process

Conventional silica sol-gel chemistry is limited for the production of transparent ultralow-density aerogels because (1) gelation is either slow or unachievable, and (2) even when gelation is achieved, the large pore sizes result in loss of transparency for aerogels <.020 g/cc. We have developed a two-step sol-gel process that circumvents the limitations of the conventional process and allows the formation of ultralow-density gels in a matter of hours. we have found that the gel time is depende… more

Date: September 1, 1991

Creator: Tillotson, T. M. & Hrubesh, L. W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Progress on sol-gel sphere-pac development

The ORNL sol-gel program is reviewed briefly. Advantages of the sol-gel sphere-pac are listed. Three sizes of microspheres are being used; the two largest sized fractions are blended and then loaded into the fuel rod, followed by packing of the smallest microspheres into void spaces using a low-energy vibrator. Sol-gel sphere-pac also appears attractive for breeder reactor fuel fabrication. (DLC)

Date: January 1, 1978

Creator: Suchomel, R R

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Sol-Gel Technology Applied to Crystalline Ceramic Nuclear Waste Forms

The sol-gel process is being developed for the solidification and isolation of high-level nuclear fuel waste. Three gelation methods are being developed for producing alternative waste forms. These include internal gelation for producing spheres of up to 1 mm diam suitable for coating, external gelation, and water extraction methods for producing material suitable for alternate ceramic processing. In this study internal gelation has been used to produce ceramic spheres of various alternative nu… more

Date: January 1, 1980

Creator: Angelini, P.; Bond, W. D.; Caputo, A. J.; Mack, J. E.; Lackey, W. J.; Lee, D. A. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Incorporation of high-level nuclear waste in gel spheres

Waste sludge is incorporated in gel spheres by the method of internal gelation. Gel spheres containing up to 90 wt % waste have been produced from defense and commercial wastes. A generic cesium-bearing waste form has been developed. Pyrolytic carbon and SiC coatings reduce the leachability of all tested articles to the detection limits.

Date: January 1, 1981

Creator: Robinson, S. M.; Arnold, W. D.; Bond, W. D.; Angelini, P. & Stinton, D. P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Densification and crystallization of zirconia thin films prepared by sol-gel processing

We have investigated the effects of precursor nature and heat treatment schedule on the densification and crystallization behavior of sol-gel derived zirconia thin films. Precursor solutions were prepared from n-propanol, zirconium (IV) n-propoxide, and either acetic acid, or 2,4-pentanedione (acac) and water additions. By controlling the ligand type and ligand-to-metal ratio, we were able to prepare films which displayed significant differences in densification behavior. We attribute the dissi… more

Date: December 31, 1993

Creator: Schwartz, R. W.; Voigt, J. A.; Buchheit, C. D. & Boyle, T. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Sol-gel coatings for high power laser optics-past, present and future

An investigation into the preparation of sol-gel coatings for high power lasers was started at LLNL in 1983 and AR coatings were successfully developed for use in the Nova laser in 1984. Several other large lasers now use these coatings. Subsequent work on HR coatings resulted in AlOOH/SiO{sub 2} and later ZrO{sub 2} or HfO{sub 2}/SiO{sub 2} systems of good optical performance. The use of organic polymer binders gave increased damage threshold and enhanced optical performance. We are in the pro… more

Date: December 21, 1993

Creator: Thomas, I. M.

Item Type: Article

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

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: Article

Partner: UNT Libraries Government Documents Department

open access

Effects of acetylacetone additions on PZT thin film processing

Sol-gel processing methods are frequently used for the fabrication of lead zirconate titanate (PZT) thin films for many electronic applications. Our standard approach for film fabrication utilizes lead acetate and acetic acid modified metal alkoxides of zirconium and titanium in the preparation of our precursor solutions. This report highlights some of our recent results on the effects of the addition of a second chelating ligand, acetylacetone, to this process. The authors discuss the changes … more

Date: February 1, 1995

Creator: Schwartz, R. W.; Assink, R. A.; Dimos, D.; Sinclair, M. B.; Boyle, T. J. & Buchheit, C. D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Structure-property relationships of carbon aerogels

Of the organic reactions in sol-gel polymerizations, the most studied reaction is the aqueous polycondensation of resorcinol with formaldehyde; the resulting crosslinked gels are supercritically dried from CO{sub 2} to give resorcinol-formaldehyde (RF) aerogels. These aerogels can be pyrolyzed to form vitreous carbon monoliths with black color, high porosity, ultrafine cell/pore size, high surface area, and interconnected particles of the organic precursor. The structure and properties of the c… more

Date: December 1, 1993

Creator: Pekala, R. W.; Alviso, C. T. & Kong, F. M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Porosity in hexylene-bridged polysilsesquioxanes: Effects of monomer concentration

Hexylene-bridged polysilsesquioxanes can be prepared as mesoporous or non-porous xerogels simply by switching from basic to acidic polymerization conditions. In this study, we looked at the effect of monomer concentration on porosity of hexylene-bridged xerogels prepared under acidic and basic conditions. 1, 6-Hexylene-bridged polysilsesquioxanes were prepared by sol-gel polymerizations of 1, 6-bis(triethoxysilyl)hexane 1 with concentrations between 0. 1 to 1.2 M in ethanol. Gelation times rang… more

Date: December 31, 1994

Creator: Baugher, B.; Loy, D. A.; Assink, R. A.; Prabakar, S.; Shea, K. J. & Oviatt, H.

Item Type: Article

Partner: UNT Libraries Government Documents Department