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Synthesis of highly ordered mesoporous silica materials using sodium silicate and amphiphilic block copolymers
E-Print Network [OSTI]
Synthesis of highly ordered mesoporous silica materials using sodium silicate and amphiphilic block) structures, using sodium silicate as the silica source and amphiphilic block copolymers as the structure of mesoporous silica material using nonionic surfac- tant and sodium silicate in the pH range 310.5. However
Kim, Ji Man
Mechanical relaxation behavior of polyurethanes reinforced with the in situ-generated sodium silica-polyphosphate nanophase
Further exploration of hybrid organic/inorganic composites (polyurethane based with inorganic material sodium silica polyphosphate) properties with mechanical relaxometer gives ability to analyze microstructure of such materials in terms of chain reptation tubes filler's fractal aggregates and stress amplification.
V. O. Dupanov; S. M. Ponomarenko
CX-000207: Categorical Exclusion Determination
Broader source: Energy.gov [DOE]
NaSi (Sodium Silicide) and Na-SG (Sodium Silica Gell) Powder Hydrogen Fuel CellsCX(s) Applied: B3.6Date: 11/23/2009Location(s): New YorkOffice(s): Energy Efficiency and Renewable Energy, Golden Field Office
Kinetics of silica polymerization
SciTech Connect (OSTI)
The polymerization of silicic acid in geothermal brine-like aqueous solutions to produce amorphous silica in colloidal form has been studied experimentally and theoretically. A large amount of high quality experimental data has been generated over the temperature rang 23 to 100{sup 0}C. Wide ranges of dissolved silica concentration, pH, and sodium chloride concentration were covered. The catalytic effects of fluoride and the reaction inhibiting effects of aluminum and boron were studied also. Two basic processes have been separately studied: the formation of new colloidal particles by the homogeneous nucleation process and the deposition of dissolved silica on pre-existing colloidal particles. A rigorous theory of the formation of colloidal particles of amorphous silica by homogeneous nucleation was developed. This theory employs the Lothe-Pound formalism, and is embodied in the computer code SILNUC which quantitatively models the homogeneous nucleation and growth of colloidal silica particles in more than enough detail for practical application. The theory and code were extensively used in planning the experimental work and analyzing the data produced. The code is now complete and running in its final form. It is capable of reproducing most of the experimental results to within experimental error. It is also capable of extrapolation to experimentally inaccessible conditions, i.e., high temperatures, rapidly varying temperature and pH, etc.
Weres, O.; Yee, A.; Tsao, L.
Kinetics of Silica Polymerization
geothermal brines:� Avoidance or minimization of silica supersaturation Supersaturation can be avoided by preventing cooling
Weres, Oleh
Silica extraction from geothermal water
DOE Patents [OSTI]
A method of producing silica from geothermal fluid containing low concentration of the silica of less than 275 ppm includes the steps of treating the geothermal fluid containing the silica by reverse osmosis treatment thereby producing a concentrated fluid containing the silica, seasoning the concentrated fluid thereby producing a slurry having precipitated colloids containing the silica, and separating the silica from the slurry.
Bourcier, William L; Bruton, Carol J
Silica in Protoplanetary Disks
Mid-infrared spectra of a few T Tauri stars (TTS) taken with the Infrared Spectrograph (IRS) on board the Spitzer Space Telescope show prominent narrow emission features indicating silica (crystalline silicon dioxide). Silica is not a major constituent of the interstellar medium; therefore, any silica present in the circumstellar protoplanetary disks of TTS must be largely the result of processing of primitive dust material in the disks surrouding these stars. We model the silica emission features in our spectra using the opacities of various polymorphs of silica and their amorphous versions computed from earth-based laboratory measurements. This modeling indicates that the two polymorphs of silica, tridymite and cristobalite, which form at successively higher temperatures and low pressures, are the dominant forms of silica in the TTS of our sample. These high temperature, low pressure polymorphs of silica present in protoplanetary disks are consistent with a grain composed mostly of tridymite named Ada found in the cometary dust samples collected from the STARDUST mission to Comet 81P/Wild 2. The silica in these protoplanetary disks may arise from incongruent melting of enstatite or from incongruent melting of amorphous pyroxene, the latter being analogous to the former. The high temperatures of 1200K-1300K and rapid cooling required to crystallize tridymite or cristobalite set constraints on the mechanisms that could have formed the silica in these protoplanetary disks, suggestive of processing of these grains during the transient heating events hypothesized to create chondrules.
B. A. Sargent; W. J. Forrest; C. Tayrien; M. K. McClure; A. Li; A. R. Basu; P. Manoj; D. M. Watson; C. J. Bohac; E. Furlan; K. H. Kim; J. D. Green; G. C. Sloan
Silica Scaling Removal Process
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
systems Water treatment systems Water evaporation systems Potential mining applications (produced water) Industry applications for which silica scaling must be prevented Benefits:...
Atomistic structure of sodium and calcium silicate intergranular films in alumina
Atomistic structure of sodium and calcium silicate intergranular films in alumina David A. Litton March 1998; accepted 21 October 1998) Sodium silicate intergranular films (IGF) in contact. The results were compared to previous simulations of calcium silicate and sol-gel silica IGF's in contact
Garofalini, Stephen H.
Novel silica-based ion exchange resin
Eichrom`s highly successful Diphonixo resin resembles a conventional ion exchange resin in its use of sulfonic acid ligands on a styrene- divinylbenzene matrix. Diphonix resin exhibits rapid exchange kinetics that allow economical operation of ion exchange systems. Unlike conventional resins, Diphonix resin contains chelating ligands that are diphosphonic acid groups that recognize and remove the targeted metals and reject the more common elements such as sodium, calcium and magnesium. This latter property makes Diphonix ideal for many industrial scale applications, including those involving waste treatment. For treatment of low-level, transuranic (TRU) and high- level radioactive wastes, Diphonix`s polystyrene backbone hinders its application due to radiolytic stability of the carbon-hydrogen bonds and lack of compatibility with expected vitrification schemes. Polystyrene-based Diphonix is approximately 60% carbon- hydrogen. In response to an identified need within the Department of Energy for a resin with the positive attributes of Diphonix that also exhibits greater radiolytic stability and final waste form compatibility, Eichrom has successfully developed a new, silica-based resin version of Diphonix. Target application for this new resin is for use in environmental restoration and waste management situations involving the processing of low-level, transuranic and high-level radioactive wastes. The resin can also be used for processing liquid mixed waste (waste that contains low level radioactivity and hazardous constituents) including mixed wastes contaminated with organic compounds. Silica-based Diphonix is only 10% carbon-hydrogen, with the bulk of the matrix silica.
Idaho Nuclear Technology and Engineering Center Sodium-Bearing Waste Treatment Research and Development FY-2002 Status Report
The Idaho National Engineering and Environmental Laboratory (INEEL) is considering several optional processes for disposal of liquid sodium-bearing waste. During fiscal year 2002, immobilization-related research included of grout formulation development for sodium-bearing waste, absorption of the waste on silica gel, and off-gas system mercury collection and breakthrough using activated carbon. Experimental results indicate that sodium-bearing waste can be immobilized in grout at 70 weight percent and onto silica gel at 74 weight percent. Furthermore, a loading of 11 weight percent mercury in sulfur-impregnated activated carbon was achieved with 99.8% off-gas mercury removal efficiency.
Herbst, Alan Keith; Deldebbio, John Anthony; Mc Cray, John Alan; Kirkham, Robert John; Olson, Lonnie Gene; Scholes, Bradley Adams
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administrationcontroller systemsBi (2)Sharing Smart GridShift EndSidneyChemistry » Silica Scaling
Coagulation chemistries for silica removal from cooling tower water.
The formation of silica scale is a problem for thermoelectric power generating facilities, and this study investigated the potential for removal of silica by means of chemical coagulation from source water before it is subjected to mineral concentration in cooling towers. In Phase I, a screening of many typical as well as novel coagulants was carried out using concentrated cooling tower water, with and without flocculation aids, at concentrations typical for water purification with limited results. In Phase II, it was decided that treatment of source or make up water was more appropriate, and that higher dosing with coagulants delivered promising results. In fact, the less exotic coagulants proved to be more efficacious for reasons not yet fully determined. Some analysis was made of the molecular nature of the precipitated floc, which may aid in process improvements. In Phase III, more detailed study of process conditions for aluminum chloride coagulation was undertaken. Lime-soda water softening and the precipitation of magnesium hydroxide were shown to be too limited in terms of effectiveness, speed, and energy consumption to be considered further for the present application. In Phase IV, sodium aluminate emerged as an effective coagulant for silica, and the most attractive of those tested to date because of its availability, ease of use, and low requirement for additional chemicals. Some process optimization was performed for coagulant concentration and operational pH. It is concluded that silica coagulation with simple aluminum-based agents is effective, simple, and compatible with other industrial processes.
Nyman, May Devan; Altman, Susan Jeanne; Stewart, Tom
Method for dissolution and stabilization of silica-rich fibers
A method is described for dissolving silica-rich fibers such as borosilicate fibers, fiberglass and asbestos to stabilize them for disposal. The method comprises (1) immersing the fibers in hot, five-weight-percent sodium hydroxide solution until the concentration of dissolved silica reaches equilibrium and a only a residue is left (about 48 hours), then immersing the residue in hot, five-weight-percent nitric acid until the residue dissolves (about 96 hours). After adjusting the pH of the dissolved fibers to be caustic, the solution can then be added to a waste vitrification stream for safe disposal. The method is useful in disposing contaminated HEME and HEPA filters. 1 fig.
Jantzen, C.M.
Electron-Irradiation Induced Nanocrystallization of Pb(II) in Silica Gels Prepared in High Magnetic Field
In a previous study, structure of silica gels prepared in a high magnetic field was investigated. While a direct application of such anisotropic silica gels is for an optical anisotropic medium possessing chemical resistance, we show here their possibility of medium in materials processing. In this direction, for example, silica hydrogels have so far been used as media of crystal growth. In this paper, as opposed to the soft-wet state, dried silica gels have been investigated. We have found that lead (II) nanocrystallites were formed induced by electron irradiation to lead (II)-doped dried silica gels prepared in a high magnetic field such as B = 10 T. Hydrogels made from a sodium metasilicate solution doped with lead (II) acetate were prepared. The dried specimens were irradiated by electrons in a transmission electron microscope environment. Electron diffraction patterns indicated the crystallinity of lead (II) nanocrystallites depending on B. An advantage of this processing technique is that the crystallin...
Kaito, Takamasa; Kaito, Chihiro
Submersible sodium pump
An electromagnetic submerged pump has an outer cylindrical stator with an inner cylindrical conductive core for the submerged pumping of sodium in the cylindrical interstitial volume defined between the stator and core. The cylindrical interstitial volume is typically vertically oriented, and defines an inlet at the bottom and an outlet at the top. The outer stator generates upwardly conveyed toroidal magnetic fields, which fields convey preferably from the bottom of the pump to the top of the pump liquid sodium in the cold leg of a sodium cooled nuclear reactor. The outer cylindrical stator has a vertically disposed duct surrounded by alternately stacked layers of coil units and laminates. 14 figs.
Brynsvold, G.V.; Lopez, J.T.; Olich, E.E.; West, C.W.
Continuous process preparation of activated silica with low carbon dioxide content gas
Iiroduced. Activated silica is the term used to designate a negatively charged colloidal particle formed by the reactien of a dilute sodium silicate solution with a dilute solution of' an acidic material or other activant. Used as a coagulant sid to alum.... paylis (5) at Chicago found that, sodium silicate could. 'be used with paper maker's alum (aluminum sulfate) as an effective c~t aid. in treating Lake l4. chigan water. Since that time several. batch processes have been cleveloyed using various...
Burdett, Joseph Walton
Detection of alkali-silica reaction swelling in concrete by staining
A method using concentrated aqueous solutions of sodium cobaltinitrite and rhodamine B is described which can be used to identify concrete that contains gels formed by the alkali-silica reaction (ASR). These solutions present little health or environmental risk, are readily applied, and rapidly discriminate between two chemically distinct gels; K-rich, Na--K--Ca--Si gels are identified by yellow staining, and alkali-poor, Ca--Si gels are identified by pink staining.
Guthrie, Jr., George D. (Santa Fe, NM); Carey, J. William (Santa Fe, NM)
A method using concentrated aqueous solutions of sodium cobalt nitrite and rhodamine B is described which can be used to identify concrete that contains gels formed by the alkali-silica reaction (ASR). These solutions present little health or environmental risk, are readily applied, and rapidly discriminate between two chemically distinct gels; K-rich, Na-K-Ca-Si gels are identified by yellow staining, and alkali-poor, Ca-Si gels are identified by pink staining.
Guthrie, G.D. Jr.; Carey, J.W.
Removal of dissolved and colloidal silica
Small amorphous silica particles are used to provide a relatively large surface area upon which silica will preferentially adsorb, thereby preventing or substantially reducing scaling caused by deposition of silica on evaporative cooling tower components, especially heat exchange surfaces. The silica spheres are contacted by the cooling tower water in a sidestream reactor, then separated using gravity separation, microfiltration, vacuum filtration, or other suitable separation technology. Cooling tower modifications for implementing the invention process have been designed.
Midkiff, William S. (Ruidoso, NM)
Stabilized fuel with silica support structure
This report describes a stabilized fuel which is supported by a silica support structure. The silica support structure provides a low density, high porosity vehicle for safely carrying hydrocarbon fuels. The silica support structure for hydrocarbon fuel does not produce toxic material residues on combustion which would pose environmentally sensitive disposal problems. The silica stabilized fuel composition is useful as a low temperature, continuous burning fire starter for wood or charcoal.
Poco, J.F.; Hrubesh, L.W.
Cellular membrane trafficking of mesoporous silica nanoparticles
This dissertation mainly focuses on the investigation of the cellular membrane trafficking of mesoporous silica nanoparticles. We are interested in the study of endocytosis and exocytosis behaviors of mesoporous silica nanoparticles with desired surface functionality. The relationship between mesoporous silica nanoparticles and membrane trafficking of cells, either cancerous cells or normal cells was examined. Since mesoporous silica nanoparticles were applied in many drug delivery cases, the endocytotic efficiency of mesoporous silica nanoparticles needs to be investigated in more details in order to design the cellular drug delivery system in the controlled way. It is well known that cells can engulf some molecules outside of the cells through a receptor-ligand associated endocytosis. We are interested to determine if those biomolecules binding to cell surface receptors can be utilized on mesoporous silica nanoparticle materials to improve the uptake efficiency or govern the mechanism of endocytosis of mesoporous silica nanoparticles. Arginine-glycine-aspartate (RGD) is a small peptide recognized by cell integrin receptors and it was reported that avidin internalization was highly promoted by tumor lectin. Both RGD and avidin were linked to the surface of mesoporous silica nanoparticle materials to investigate the effect of receptor-associated biomolecule on cellular endocytosis efficiency. The effect of ligand types, ligand conformation and ligand density were discussed in Chapter 2 and 3. Furthermore, the exocytosis of mesoporous silica nanoparticles is very attractive for biological applications. The cellular protein sequestration study of mesoporous silica nanoparticles was examined for further information of the intracellular pathway of endocytosed mesoporous silica nanoparticle materials. The surface functionality of mesoporous silica nanoparticle materials demonstrated selectivity among the materials and cancer and normal cell lines. We aimed to determine the specific organelle that mesoporous silica nanoparticles could approach via the identification of harvested proteins from exocytosis process. Based on the study of endo- and exocytosis behavior of mesoporous silica nanoparticle materials, we can design smarter drug delivery vehicles for cancer therapy that can be effectively controlled. The destination, uptake efficiency and the cellular distribution of mesoporous silica nanoparticle materials can be programmable. As a result, release mechanism and release rate of drug delivery systems can be a well-controlled process. The deep investigation of an endo- and exocytosis study of mesoporous silica nanoparticle materials promotes the development of drug delivery applications.
Fang, I-Ju
Silica Supported Ceria Nanoparticles: A Hybrid Nanostructure...
The surface chemical and vibrational spectroscopy analysis revealed cerium�silicate (Ce-O-Si) covalent bond linkage between silica and cerium oxide nanoparticles. The...
1 AQUEOUS SILICA POLYMERIZATION IN Silica polymers have long been recognized in aque-
1 AQUEOUS SILICA POLYMERIZATION IN PURE H2O Silica polymers have long been recognized in aque- ous is accompanied by increased extent of polymerization. Silica concentrations in equilibrium with quartz. In the system SiO2-H2O, the structure of supercritical hy- drous SiO2 melt is strongly polymerized at
Manning, Craig
Silica Geothermometers | Open Energy Information
Open Energy Info (EERE)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home5b9fcbce19 No revisionEnvReviewNonInvasiveExplorationUT-g Grant ofRichardton AbbeyARaftPadomaSierra Leone)Sikes Act JumpSilica
Characterizing Surface Acidic Sites in Mesoporous-Silica-Supported...
Surface Acidic Sites in Mesoporous-Silica-Supported Tungsten Oxide Catalysts Using Solid State NMR and Quantum Characterizing Surface Acidic Sites in Mesoporous-Silica-Supported...
Synthesis of supported carbon nanotubes in mineralized silica...
supported carbon nanotubes in mineralized silica-wood composites. Synthesis of supported carbon nanotubes in mineralized silica-wood composites. Abstract: Multiwall carbon...
Synthesis and properties of Chitosan-silica hybrid aerogels
chitosan-silica composite aerogels can be easily synthesizedphysical properties of these aerogels. These materials may1. Top: Chitosan-silica aerogel (sample 4), Bottom: Same
Ayers, Michael R.; Hunt, Arlon J.
Sample Desorption/Onization From Mesoporous Silica
Mesoporous silica is shown to be a sample holder for laser desorption/ionization of mass spectrometry. Supported mesoporous silica was prepared by coating an ethanolic silicate solution having a removable surfactant onto a substrate to produce a self-assembled, ordered, nanocomposite silica thin film. The surfactant was chosen to provide a desired pore size between about 1 nanometer diameter and 50 nanometers diameter. Removal of the surfactant resulted in a mesoporous silica thin film on the substrate. Samples having a molecular weight below 1000, such as C.sub.60 and tryptophan, were adsorbed onto and into the mesoporous silica thin film sample holder and analyzed using laser desorption/ionization mass spectrometry.
Iyer, Srinivas (Los Alamos, NM); Dattelbaum, Andrew M. (Los Alamos, NM)
ID-69 Sodium drain experiments
This paper describes experiments to determine the sodium retention and drainage from the two key areas of an ID-69. This information is then used as the initiation point for guidelines of how to proceed with washing an ID-69 in the IEM Cell Sodium Removal System.
Johnston, D.C.
Sodium loop framework structural analysis
This document provides the structural analysis of the Sodium Loop framework in a drop condition. The drop is similar to the US Department of Transportation non-bulk, performance-oriented packaging (Packaging Group I) drop test. The drop height evaluated for the Sodium Loop framework is 5.9 ft.
Nguyen, P.M.
Hollow silica and silica-boron nano/microparticles for contrast-enhanced ultrasound to detect small tumors
Hollow silica and silica-boron nano/microparticles for contrast-enhanced ultrasound to detect small Accepted 18 March 2012 Available online 11 April 2012 Keywords: Ultrasound Nano Silica Shells Imaging detection, gas filled hollow boron-doped silica particles have been developed, which can be used
Kummel, Andrew C.
Tables of thermodynamic properties of sodium
The thermodynamic properties of saturated sodium, superheated sodium, and subcooled sodium are tabulated as a function of temperature. The temperature ranges are 380 to 2508 K for saturated sodium, 500 to 2500 K for subcooled sodium, and 400 to 1600 K for superheated sodium. Tabulated thermodynamic properties are enthalpy, heat capacity, pressure, entropy, density, instantaneous thermal expansion coefficient, compressibility, and thermal pressure coefficient. Tables are given in SI units and cgs units.
Fink, J.K.
S.S. , "Coherent Expanded Aerogels," J. of Phys. Chern.Production of Silica Aerogel," Physica Scripta 23, Nicolaon,S.J. , "Preparation des aerogels de silice a partir
Hunt, A.J.
Independent Oversight Review, Sodium Bearing Waste Treatment...
Energy Savers [EERE]
Federal - June 2012 Independent Oversight Review, Sodium Bearing Waste Treatment Project - Federal - June 2012 June 2012 Review of the Sodium Bearing Waste Treatment Project -...
Contractor - June 2012 Independent Oversight Review, Sodium Bearing Waste Treatment Project - Contractor - June 2012 June 2012 Review of the Sodium Bearing Waste Treatment Project...
Simulation of sodium boiling experiments with THERMIT sodium version
Natural and forced convection experiments(SBTF and French) are simulated with the sodium version of the thermal-hydraulic computer code THERMIT. Simulation is done for the test secti- -on with the pressure-velocity boundary ...
Huh, Kang Yul
Properties and Structures of Sulfonated Syndiotactic Polystyrene Aerogel and Syndiotactic Polystyrene/Silica Hybrid Aerogel.
??This study focuses on hybrid aerogels of syndiotactic polystyrene (sPS) and silica where silica concentration is varied and silica condensation conditions are varied to produce� (more)
Zhang, Huan
The Management of Silica in Los Alamos National Laboratory Tap Water - A Study of Silica Solubility
Well water at Los Alamos National Laboratory (LANL) has a silica (SiO{sub 2}) content of 60 to 100 mg/L, with 4 mg/L of magnesium, 13 mg/L calcium and lesser concentrations of other ions. On evaporation in cooling towers, when the silica concentration reaches 150 to 220 mg/L, silica deposits on heat transfer surfaces. When the high silica well water is used in the reprocessing of plutonium, silica remains in solution at the end of the process and creates a problem of removal from the effluent prior to discharge or evaporation. The work described in this Report is divided into two major parts. The first part describes the behavior of silica when the water is evaporated at various conditions of pH and in the presence of different classes of anions: inorganic and organic. In the second part of this work it was found that precipitation (floccing) of silica was a function of solution pH and mole ratio of metal to silica.
Wohlberg, C.; Worland, V.P.; Kozubal, M.A.; Erickson, G.F.; Jacobson, H.M.; McCarthy, K.T.
E-Print Network 3.0 - alumina silica-alumina etude Sample Search...
14 (2004) 681686 PII: S0960-1317(04)71691-5 Summary: for silica, alumina, and titania aerogels. Silica and alumina aerogel cantilevers are fabricated on the basis... Silica Silica...
High resolution patterning of silica aerogels
Three-dimensional metallic structures are fabricated with high spatial resolution in silica aerogels. In our method, silica hydrogels are prepared with a standard base-catalyzed route, and exchanged with an aqueous solution typically containing Ag{sup +} ions (1 M) and 2-propanol (0.2 M). The metal ions are reduced photolytically with a table-top ultraviolet lamp, or radiolytically, with a focused X-ray beam. We fabricated dots and lines as small as 30 x 70 {micro}m, protruding for several mm into the bulk of the materials. The hydrogels are eventually supercritically dried to yield aerogels, without any measurable change in the shape and spatial resolution of the lithographed structures. Transmission electron microscopy shows that illuminated regions are composed by Ag clusters with a size of several {micro}m, separated by thin layers of silica.
Bertino, M.F.; Hund, J.F.; Sosa, J.; Zhang, G.; Sotiriou-Leventis, C.; Leventis, N.; Tokuhiro, A.T.; Terry, J. (UMR-MUST); (IIT)
Measurement of muonium emission from silica aerogel
Emission of muonium ($\\mu^{+}e^{-}$) atoms from silica aerogel into vacuum was observed. Characteristics of muonium emission were established from silica aerogel samples with densities in the range from 29 mg cm$^{-3}$ to 178 mg cm$^{-3}$. Spectra of muonium decay times correlated with distances from the aerogel surfaces, which are sensitive to the speed distributions, follow general features expected from a diffusion process, while small deviations from a simple room-temperature thermal diffusion model are identified. The parameters of the diffusion process are deduced from the observed yields.
P. Bakule; G. A. Beer; D. Contreras; M. Esashi; Y. Fujiwara; Y. Fukao; S. Hirota; H. Iinuma; K. Ishida; M. Iwasaki; T. Kakurai; S. Kanda; H. Kawai; N. Kawamura; G. M. Marshall; H. Masuda; Y. Matsuda; T. Mibe; Y. Miyake; S. Okada; K. Olchanski; A. Olin; H. Onishi; N. Saito; K. Shimomura; P. Strasser; M. Tabata; D. Tomono; K. Ueno; K. Yokoyama; S. Yoshida
Bakule, P; Contreras, D; Esashi, M; Fujiwara, Y; Fukao, Y; Hirota, S; Iinuma, H; Ishida, K; Iwasaki, M; Kakurai, T; Kanda, S; Kawai, H; Kawamura, N; Marshall, G M; Masuda, H; Matsuda, Y; Mibe, T; Miyake, Y; Okada, S; Olchanski, K; Olin, A; Onishi, H; Saito, N; Shimomura, K; Strasser, P; Tabata, M; Tomono, D; Ueno, K; Yokoyama, K; Yoshida, S
A threshold Cherenkov detector for K separation using silica aerogel
A threshold Cherenkov detector for Kþ =pþ separation using silica aerogel R. Siudak a,b , A August 2008 Keywords: Threshold Cherenkov detector Silica aerogel Reaction pp ! Kþ ðLp�? Kþ =pþ separation in the focal plane of a magnetic spectrograph. Silica aerogel with refractive index of n ¼ 1:05 is applied
Magiera, Andrzej
Surface-Driven Sodium Ion Energy Storage in Nanocellular Carbon...
Surface-Driven Sodium Ion Energy Storage in Nanocellular Carbon Foams. Surface-Driven Sodium Ion Energy Storage in Nanocellular Carbon Foams. Abstract: Sodium ion (Na+) batteries...
anticoagulant sodium citrate: Topics by E-print Network
pressure-velocity boundary ... Huh, Kang Yul 1982-01-01 38 Ground beef shelf life assessment as influenced by sodium lactate, sodium propionate, sodium diacetate, and soy...
Catalysis over activated high silica zeolites
A process is provided for conducting organic compound conversion over a catalyst composition comprising a crystalline zeolite having a high initial silica-to-alumina mole ratio, said zeolite being prepared by calcining the zeolite, contacting said calcined zeolite with solid aluminum fluoride, and coverting said aluminum fluoride contacted material to hydrogen form.
Chang, C. D.; Miale, N.
Chemistry of Silica in Cerro Prieto Brines
1975). When operated without sludge r e c i r c u l a t i ot o c o l l o i d a l silica. sludge accumulation there. thel a t i o n of part of the sludge coming out of The l a r g
Weres, O.
Molecular sieving silica membrane fabrication process
A process for producing a molecular sieve silica membrane comprising depositing a hybrid organic-inorganic polymer comprising at least one organic constituent and at least one inorganic constituent on a porous substrate material and removing at least a portion of the at least one organic constituent of the hybrid organic-inorganic polymer, forming a porous film.
Raman, Narayan K. (Monroeville, PA); Brinker, Charles Jeffrey (Albuquerque, NM)
Conversion of geothermal waste to commercial products including silica
A process for the treatment of geothermal residue includes contacting the pigmented amorphous silica-containing component with a depigmenting reagent one or more times to depigment the silica and produce a mixture containing depigmented amorphous silica and depigmenting reagent containing pigment material; separating the depigmented amorphous silica and from the depigmenting reagent to yield depigmented amorphous silica. Before or after the depigmenting contacting, the geothermal residue or depigmented silica can be treated with a metal solubilizing agent to produce another mixture containing pigmented or unpigmented amorphous silica-containing component and a solubilized metal-containing component; separating these components from each other to produce an amorphous silica product substantially devoid of metals and at least partially devoid of pigment. The amorphous silica product can be neutralized and thereafter dried at a temperature from about 25.degree. C. to 300.degree. C. The morphology of the silica product can be varied through the process conditions including sequence contacting steps, pH of depigmenting reagent, neutralization and drying conditions to tailor the amorphous silica for commercial use in products including filler for paint, paper, rubber and polymers, and chromatographic material.
Premuzic, Eugene T. (East Moriches, NY); Lin, Mow S. (Rocky Point, NY)
Carbon nanomaterials in silica aerogel matrices
Silica aerogels are ultra low-density, high surface area materials that are extremely good thermal insulators and have numerous technical applications. However, their mechanical properties are not ideal, as they are brittle and prone to shattering. Conversely, single-walled carbon nanotubes (SWCNTs) and graphene-based materials, such as graphene oxide, have extremely high tensile strength and possess novel electronic properties. By introducing SWCNTs or graphene-based materials into aerogel matrices, it is possible to produce composites with the desirable properties of both constituents. We have successfully dispersed SWCNTs and graphene-based materials into silica gels. Subsequent supercritical drying results in monolithic low-density composites having improved mechanical properties. These nanocomposite aerogels have great potential for use in a wide range of applications.
Hamilton, Christopher E [Los Alamos National Laboratory; Chavez, Manuel E [Los Alamos National Laboratory; Duque, Juan G [Los Alamos National Laboratory; Gupta, Gautam [Los Alamos National Laboratory; Doorn, Stephen K [Los Alamos National Laboratory; Dattelbaum, Andrew M [Los Alamos National Laboratory; Obrey, Kimberly A D [Los Alamos National Laboratory
Fire suppressing apparatus. [sodium fires
Apparatus for smothering a liquid sodium fire comprises a pan, a perforated cover on the pan, and tubed depending from the cover and providing communication between the interior of the pan and the ambient atmosphere through the perforations in the cover. Liquid caught in the pan rises above the lower ends of the tubes and thus serves as a barrier which limits the amount of air entering the pan.
Buttrey, K.E.
Light-scattering studies of silica aerogels
Due to its combination of transparency and low thermal conductivity, aerogel holds considerable promise for use as insulating window materials for residential and commercial applications. This paper reports on the preliminary investigation of the optical and scattering properties of silica aerogels. It briefly describes the properties of aerogels important for window glazing applications. The optical properties are then described, followed by a discussion of the scattering measurements and their interpretation.
Recent progress in silica aerogel Cherenkov radiator
In this paper, we present recent progress in the development of hydrophobic silica aerogel as a Cherenkov radiator. In addition to the conventional method, the recently developed pin-drying method for producing high-refractive-index aerogels with high transparency was studied in detail. Optical qualities and large tile handling for crack-free aerogels were investigated. Sufficient photons were detected from high-performance aerogels in a beam test.
Makoto Tabata; Ichiro Adachi; Hideyuki Kawai; Masato Kubo; Takeshi Sato
Tabata, Makoto; Kawai, Hideyuki; Kubo, Masato; Sato, Takeshi
Silica powders for powder evacuated thermal insulating panel and method
A powder evacuated thermal insulating panel using generally spherical and porous silica particles of a median size less than about 100 nanometers in diameter, a pour packing density of about 0.4 to 0.6 g/cm{sup 3} and an external surface area in the range of about 90 to 600 m{sup 2}/g is described. The silica powders are prepared by reacting a tetraalkyl silicate with ammonia and water in an alcohol solvent, distilling the solution after the reaction to remove the ammonia and recover the alcohol. The resulting aqueous slurry was dried, ball-milled, and dried again to provide the silica particles with defined internal and external porosity. The nanometer size and the large external surface area of the silica particles along with the internal and external porosity of the silica particles provide powder evacuated thermal insulating panels with significantly higher R-values than obtainable using previously known silica powders. 2 figs.
Harris, M.T.; Basaran, O.A.; Kollie, T.G.; Weaver, F.J.
A powder evacuated thermal insulating panel using generally spherical and porous silica particles of a median size less than about 100 nanometers in diameter, a pour packing density of about 0.4 to 0.6 g/cm.sup.3 and an external surface area in the range of about 90 to 600 m.sup.2/ g is described. The silica powders are prepared by reacting a tetraakyl silicate with ammonia and water in an alcohol solvent, distilling the solution after the reaction to remove the ammonia and recover the alcohol. The resulting aqueous slurry was dried, ball-milled, and dried again to provide the silica particles with defined internal and external porosity. The nanometer size and the large external surface area of the silica particles along with the internal and external porosity of the silica particles provide powder evacuated thermal insulating panels with significantly higher R-values than obtainable using previously known silica powders.
Harris, Michael T. (Knoxville, TN); Basaran, Osman A. (Oak Ridge, TN); Kollie, Thomas G. (Oak Ridge, TN); Weaver, Fred J. (Knoxville, TN)
A powder evacuated thermal insulating panel using generally spherical and porous silica particles of a median size less than about 100 nanometers in diameter, a pour packing density of about 0.4 to 0.6 g/cm.sup.3 and an external surface area in the range of about 90 to 600 m.sup.2 /g is described. The silica powders are prepared by reacting a tetraakyl silicate with ammonia and water in an alcohol solvent, distilling the solution after the reaction to remove the ammonia and recover the alcohol. The resulting aqueous slurry was dried, ball-milled, and dried again to provide the silica particles with defined internal and external porosity. The nanometer size and the large external surface area of the silica particles along with the internal and external porosity of the silica particles provide powder evacuated thermal insulating panels with significantly higher R-values than obtainable using previously known silica powders.
Characterisation of Dust Particles Trapped in Silica Aerogels.
?? This thesis involves the study of dust particles trapped in silica aerogel for fusion dust diagnostics purpose. The low velocity impact experiments are done� (more)
Liu, Bing
Feasibility of using silica aerogel as insulation for buildings.
?? For recent years, silica aerogel has attracted great attention and been extensively used in different technical fields owning to its remarkable properties in optics,� (more)
Huang, Lang
Independent Oversight Assessment, Idaho Cleanup Project Sodium...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Bearing Waste Treatment Project - November 2012 November 2012 Assessment of Nuclear Safety Culture at the Idaho Cleanup Project Sodium Bearing Waste Treatment Project This...
The analysis will show the consequences should the solid sodium in the Secondary Sodium Tank react with a presumed layer of water in the cell. The Peer Review Checklist is attached.
A layered sodium titanate as promising anode material for sodium ion batteries
Sodium ion batteries have recently received great attention for large-scale energy applications because of the abundance and low cost of sodium source. Although some cathode materials with desirable electrochemical properties ...
Wu, Di, S.M. Massachusetts Institute of Technology
Electrolytic process to produce sodium hypochlorite using sodium ion conductive ceramic membranes
An electrochemical process for the production of sodium hypochlorite is disclosed. The process may potentially be used to produce sodium hypochlorite from seawater or low purity un-softened or NaCl-based salt solutions. The process utilizes a sodium ion conductive ceramic membrane, such as membranes based on NASICON-type materials, in an electrolytic cell. In the process, water is reduced at a cathode to form hydroxyl ions and hydrogen gas. Chloride ions from a sodium chloride solution are oxidized in the anolyte compartment to produce chlorine gas which reacts with water to produce hypochlorous and hydrochloric acid. Sodium ions are transported from the anolyte compartment to the catholyte compartment across the sodium ion conductive ceramic membrane. Sodium hydroxide is transported from the catholyte compartment to the anolyte compartment to produce sodium hypochlorite within the anolyte compartment.
Balagopal, Shekar; Malhotra, Vinod; Pendleton, Justin; Reid, Kathy Jo
Fibrous composites comprising carbon nanotubes and silica
Fibrous composite comprising a plurality of carbon nanotubes; and a silica-containing moiety having one of the structures: (SiO).sub.3Si--(CH.sub.2).sub.n--NR.sub.1R.sub.2) or (SiO).sub.3Si--(CH.sub.2).sub.n--NCO; where n is from 1 to 6, and R.sub.1 and R.sub.2 are each independently H, CH.sub.3, or C.sub.2H.sub.5.
Peng, Huisheng (Shanghai, CN); Zhu, Yuntian Theodore (Cary, NC); Peterson, Dean E. (Los Alamos, NM); Jia, Quanxi (Los Alamos, NM)
Hydrophobic silica aerogel production at KEK
We present herein a characterization of a standard method used at the High Energy Accelerator Research Organization (KEK) to produce hydrophobic silica aerogels and expand this method to obtain a wide range of refractive index (n = 1.006-1.14). We describe in detail the entire production process and explain the methods used to measure the characteristic parameters of aerogels, namely the refractive index, transmittance, and density. We use a small-angle X-ray scattering (SAXS) technique to relate the transparency to the fine structure of aerogels.
Tabata, Makoto; Kawai, Hideyuki; Sumiyoshi, Takayuki; Yokogawa, Hiroshi
Makoto Tabata; Ichiro Adachi; Hideyuki Kawai; Takayuki Sumiyoshi; Hiroshi Yokogawa
Electroactive Silica Nanoparticles for Biological Labeling. | EMSL
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed NewcatalystNeutronEnvironmentZIRKLEEFFECTSHighElectroactive Silica Nanoparticles for
Dye-Doped Silica Nanoparticle Labels/Protein Microarray for Detection...
Dye-Doped Silica Nanoparticle LabelsProtein Microarray for Detection of Protein Biomarkers. Dye-Doped Silica Nanoparticle LabelsProtein Microarray for Detection of Protein...
Tailoring Structure Property Relationships and Elastic Phenomenon in Native and Polymer Reinforced Silica Aerogels.
?? The focus of this work was to study the effects of flexible silica backbones on elastic properties of silica aerogels. Two routes were examined.� (more)
Randall, Jason P.
Community Geothermal Technology Program: Silica bronze project. Final report
Objective was to incorporate waste silica from the HGP-A geothermal well in Pohoiki with other refractory materials for investment casting of bronze sculpture. The best composition for casting is about 50% silica, 25% red cinders, and 25% brick dust; remaining ingredient is a binder, such as plaster and water.
Bianchini, H.
ALUMINOSILICATE-COATED SILICA SAND FOR REACTIVE TRANSPORT EXPERIMENTS By JORGE ANTONIO JEREZ transport experiments; Dr. Barbara Williams and Jason Shira from University of Idaho for providing access-COATED SILICA SAND FOR REACTIVE TRANSPORT EXPERIMENTS Abstract by Jorge Antonio Jerez Briones, Ph.D. Washington
Flury, Markus
E-Print Network 3.0 - aqueous sodium dodecyl Sample Search Results
of Sodium Dodecyl Sulfate and Sodium Dodecyl Benzenesulfonate on Poly(Vinyl Chloride) Latexes Summary: 1 Adsorption of Sodium Dodecyl Sulfate and Sodium Dodecyl...
Atlas Sodium Automated Batch Synthesis System
Atlas Sodium Automated Batch Synthesis System (Syrris) June 2013 #12;Introduction to the system · The Atlas Sodium system consists of an Atlas base equipped with a 400ºC hotplate, a stacking dry bath systemL) for automated addition and/or removal of solution. · The system is computer controlled by the Atlas software
Subramanian, Venkat
Sodium Heat Engine Development Program
The Sodium Heat Engine (SHE) is an efficient thermoelectric conversion device which directly generates electricity from a thermally regenerative electrochemical cell that relies on the unique conduction properties of {beta}{double prime}-alumina solid electrolyte (BASE). Laboratory models of a variety of SHE devices have demonstrated the feasibility and efficiency of the system, engineering development of large prototype devices has been slowed by a series of materials and fabrication problems. Failure of the electrolyte tubes has been a recurring problem and a number of possible causes have been postulated. To address these issues, a two-phase engineering development program was undertaken. This report summarizes the final results of the first phase of the program, which included extensive materials characterization activities, a study of applicable nondestructive evaluation methods, an investigation of possible stress states that would contribute to fracture, and certain operational issues associated with the electromagnetic pumps used in the SHE prototype. Mechanical and microstructural evaluation of commercially obtained BASE tubes revealed that they should be adequate for SHE applications and that sodium exposure produced no appreciable deleterious strength effects. Processing activities to produce a more uniform and smaller grain size for the BASE tubes were completed using isostatic pressing, extrusion, and slip casting. Green tubes were sintered by conventional and microwave plasma methods. Of particular interest is the residual stress state in the BASE tubes, and both analysis and nondestructive evaluation methods were employed to evaluate these stresses. X-ray and neutron diffraction experiments were performed to determine the bulk residual stresses in commercially fabricated BASE tubes; however, tube-to-tube variations and variations among the various methods employed did not allow formulation of a definitive definition of the as-fabricated stress state.
Singh, J.P.; Kupperman, D.S.; Majumdar, S.; Dorris, S.; Gopalsami, N.; Dieckman, S.L.; Jaross, R.A.; Johnson, D.L.; Gregar, J.S.; Poeppel, R.B.; Raptis, A.C.; Valentin, R.A.
In-situ method for treating residual sodium
A unique process for deactivating residual sodium in Liquid Metal Fast Breeder Reactor (LMFBR) systems which uses humidified (but not saturated) carbon dioxide at ambient temperature and pressure to convert residual sodium into solid sodium bicarbonate.
Sherman, Steven R. (Idaho Falls, ID); Henslee, S. Paul (Idaho Falls, ID)
In-Situ Method for Treating Residual Sodium
Sherman, Steven R.; Henslee, S. Paul
SciTech Connect: Thermodynamic and transport properties of sodium...
Office of Scientific and Technical Information (OSTI)
on thermophysical properties of sodium have been included in this critical assessment. Thermodynamic properties of sodium liquid and vapor that have been assessed...
Development of Silica Aerogel with Any Density
Abstract�New production methods of silica aerogel with high and low refractive indices have been developed. A very slow shrinkage of alcogel at room temperature has made possible producing aerogel with high refractive indices of up to 1.265 without cracks. Even higher refractive indices than 1.08, the transmission length of the aerogel obtained from this technique has been measured to be about 10 to 20 mm at 400 nm wave length. A mold made of alcogel which endures shrinkage in the supercritical drying process has provided aerogel with the extremely low density of 0.009g/cm 3, which corresponds to the refractive index of 1.002. We have succeeded producing aerogel with a wide range of densities. I.
M. Tabata; I. Adachi; T. Fukushima; H. Kawai; H. Kishimoto; A. Kuratani; H. Nakayama; S. Nishida; T. Noguchi; K. Okudaira; Y. Tajima; H. Yano; H. Yokogawa; H. Yoshida
Ambient-pressure silica aerogel films
Very highly porous (aerogel) silica films with refractive index in the range 1.006--1.05 (equivalent porosity 98.5--88%) were prepared by an ambient-pressure process. It was shown earlier using in situ ellipsometric imaging that the high porosity of these films was mainly attributable to the dilation or `springback` of the film during the final stage of drying. This finding was irrefutably reconfirmed by visually observing a `springback` of >500% using environmental scanning electron microscopy (ESEM). Ellipsometry and ESEM also established the near cent per cent reversibility of aerogel film deformation during solvent intake and drying. Film thickness profile measurements (near the drying line) for the aerogel, xerogel and pure solvent cases are presented from imaging ellipsometry. The thickness of these films (crack-free) were controlled in the range 0.1-3.5 {mu}m independent of refractive index.
Prakash, S.S. [New Mexico Univ., Albuquerque, NM (United States); Brinker, C.J. [New Mexico Univ., Albuquerque, NM (United States)]|[Sandia National Labs., Albuquerque, NM (United States); Hurd, A.J. [Sandia National Labs., Albuquerque, NM (United States)
Laser Damage Precursors in Fused Silica
There is a longstanding, and largely unexplained, correlation between the laser damage susceptibility of optical components and both the surface quality of the optics, and the presence of near surface fractures in an optic. In the present work, a combination of acid leaching, acid etching, and confocal time resolved photoluminescence (CTP) microscopy has been used to study laser damage initiation at indentation sites. The combination of localized polishing and variations in indentation loads allows one to isolate and characterize the laser damage susceptibility of densified, plastically flowed and fractured fused silica. The present results suggest that: (1) laser damage initiation and growth are strongly correlated with fracture surfaces, while densified and plastically flowed material is relatively benign, and (2) fracture events result in the formation of an electronically defective rich surface layer which promotes energy transfer from the optical beam to the glass matrix.
Miller, P; Suratwala, T; Bude, J; Laurence, T A; Shen, N; Steele, W A; Feit, M; Menapace, J; Wong, L
Luminescent organosilicon polymers and sol-gel synthesis of nano-structured silica
filled � hollow � silica � nano-�? � and � microshells �nano-�? extracting �sensor. � Conclusions � The � adsorptive � properties � of � hollow �
Martinez, H. Paul
A resting bottom sodium cooled fast reactor
This follows ICAPP 2011 paper 11059 'Fast Reactor with a Cold Bottom Vessel', on sodium cooled reactor vessels in thermal gradient, resting on soil. Sodium is frozen on vessel bottom plate, temperature increasing to the top. The vault cover rests on the safety vessel, the core diagrid welded to a toric collector forms a slab, supported by skirts resting on the bottom plate. Intermediate exchangers and pumps, fixed on the cover, plunge on the collector. At the vessel top, a skirt hanging from the cover plunges into sodium, leaving a thin circular slit partially filled by sodium covered by argon, providing leak-tightness and allowing vessel dilatation, as well as a radial relative holding due to sodium inertia. No 'air conditioning' at 400 deg. C is needed as for hanging vessels, and this allows a large economy. The sodium volume below the slab contains isolating refractory elements, stopping a hypothetical corium flow. The small gas volume around the vessel limits any LOCA. The liner cooling system of the concrete safety vessel may contribute to reactor cooling. The cold resting bottom vessel, proposed by the author for many years, could avoid the complete visual inspection required for hanging vessels. However, a double vessel, containing support skirts, would allow introduction of inspecting devices. Stress limiting thermal gradient is obtained by filling secondary sodium in the intermediate space. (authors)
Costes, D. [Consultant (France)
IAEA sodium void reactivity benchmark calculations
In this paper, the IAEA-1 992 ``Benchmark Calculation of Sodium Void Reactivity Effect in Fast Reactor Core`` problem is evaluated. The proposed design is a large axially heterogeneous oxide-fueled fast reactor as described in Section 2; the core utilizes a sodium plenum above the core to enhance leakage effects. The calculation methods used in this benchmark evaluation are described in Section 3. In Section 4, the calculated core performance results for the benchmark reactor model are presented; and in Section 5, the influence of steel and interstitial sodium heterogeneity effects is estimated.
Hill, R.N.; Finck, P.J.
In this paper, the IAEA-1 992 Benchmark Calculation of Sodium Void Reactivity Effect in Fast Reactor Core'' problem is evaluated. The proposed design is a large axially heterogeneous oxide-fueled fast reactor as described in Section 2; the core utilizes a sodium plenum above the core to enhance leakage effects. The calculation methods used in this benchmark evaluation are described in Section 3. In Section 4, the calculated core performance results for the benchmark reactor model are presented; and in Section 5, the influence of steel and interstitial sodium heterogeneity effects is estimated.
Quantification of residual stress from photonic signatures of fused silica
A commercially available grey-field polariscope (GFP) instrument for photoelastic examination is used to assess impact damage inflicted upon the outer-most pane of Space Shuttle windows made from fused silica. A method and apparatus for calibration of the stress-optic coefficient using four-point bending is discussed. The results are validated on known material (acrylic) and are found to agree with literature values to within 6%. The calibration procedure is then applied to fused-silica specimens and the stress-optic coefficient is determined to be 2.43 � 0.54 � 10{sup ?12} Pa{sup ?1}. Fused silica specimens containing impacts artificially made at NASA�s Hypervelocity Impact Technology Facility (HIT-F), to simulate damage typical during space flight, are examined. The damage sites are cored from fused silica window carcasses and examined with the GFP. The calibrated GFP measurements of residual stress patterns surrounding the damage sites are presented.
Cramer, K. Elliott; Yost, William T. [NASA Langley Research Center, Hampton, VA 23681 (United States); Hayward, Maurice [College of William and Mary, Williamsburg, VA 23185 (United States)
Preparation, characterization and applications of monolithic titania-silica aerogels.
??In this work, new monolithic titania-silica aerogel materials were developed and evaluated. It started with the synthesis using modified sol-gel processes to obtain crack-free monolithic� (more)
Cao, Shengli
aminopropyl silica gel: Topics by E-print Network
Summary: We present optical and X-ray radiographical characterization of silica aerogels with refractive index from 1.05 to 1.07 for a Cherenkov radiator. A novel pin-drying...
amorphous silica systems: Topics by E-print Network
progress in the development and mass production of large-area hydrophobic silica aerogels for use as radiators in the aerogel-based ring-imaging Cherenkov (A-RICH) counter,...
Operating Experience Level 3, Dangers of Respirable Silica
This Operating Experience Level 3 (OE-3) document provides information on a safety concern related to recurring worker exposure to dust containing crystalline silica at Department of Energy (DOE) sites.
Electrospinning of silica nanofibers: characterization and application to biosensing
; and the pore size is around several nanometers to a micrometer wide. In this work, the relationship between the diameter of electrospun silica fibers, experimental parameters such as concentration and voltage, and between pore size of the fiber membrane...
Tsou, Pei-Hsiang
Experimental evaluation of heat transfer characteristics of silica nanofluid
The laminar convective heat transfer characteristics were investigated for silica nanofluid. An experimental loop was built to obtain heat transfer coefficients for single-phase nanofluids in a circular conduit in laminar ...
Zhang, Zihao, S.B. Massachusetts Institute of Technology
Radial power flattening in sodium fast reactors
In order to improve a new design for a uranium startup sodium cooled fast reactor which was proposed at MIT, this thesis evaluated radial power flattening by varying the fuel volume fraction at a fixed U-235 enrichment of ...
Krentz-Wee, Rebecca (Rebecca Elizabeth)
Sodium Alanate Nanoparticles for Hydrogen Storage.
??Preparation and characterization of sodium alanate (NaAlH4) based hydrogen storage materials are described in this book. The effect of the NaAlH4 particle size, particularly in� (more)
Bald�, C.P.
Kinetics of wet sodium vapor complex plasma
In this paper, we have investigated the kinetics of wet (partially condensed) Sodium vapor, which comprises of electrons, ions, neutral atoms, and Sodium droplets (i) in thermal equilibrium and (ii) when irradiated by light. The formulation includes the balance of charge over the droplets, number balance of the plasma constituents, and energy balance of the electrons. In order to evaluate the droplet charge, a phenomenon for de-charging of the droplets, viz., evaporation of positive Sodium ions from the surface has been considered in addition to electron emission and electron/ion accretion. The analysis has been utilized to evaluate the steady state parameters of such complex plasmas (i) in thermal equilibrium and (ii) when irradiated; the results have been graphically illustrated. As a significant outcome irradiated, Sodium droplets are seen to acquire large positive potential, with consequent enhancement in the electron density.
Mishra, S. K., E-mail: firstname.lastname@example.com [Institute for Plasma Research (IPR), Gandhinagar 382428 (India); Sodha, M. S. [Centre of Energy Studies, Indian Institute of Technology Delhi (IITD), New Delhi 110016 (India)] [Centre of Energy Studies, Indian Institute of Technology Delhi (IITD), New Delhi 110016 (India)
Silica Extraction at the Mammoth Lakes Geothermal Site
The purpose of this project is to develop a cost-effective method to extract marketable silica (SiO{sub 2}) from fluids at the Mammoth Lakes, California geothermal power plant. Marketable silica provides an additional revenue source for the geothermal power industry and therefore lowers the costs of geothermal power production. The use of this type of ''solution mining'' to extract resources from geothermal fluids eliminates the need for acquiring these resources through energy intensive and environmentally damaging mining technologies. We have demonstrated that both precipitated and colloidal silica can be produced from the geothermal fluids at Mammoth Lakes by first concentrating the silica to over 600 ppm using reverse osmosis (RO). The RO permeate can be used in evaporative cooling at the plant; the RO concentrate is used for silica and potentially other (Li, Cs, Rb) resource extraction. Preliminary results suggest that silica recovery at Mammoth Lakes could reduce the cost of geothermal electricity production by 1.0 cents/kWh.
Bourcier, W; Ralph, W; Johnson, M; Bruton, C; Gutierrez, P
The Sodium Process Facility at Argonne National Laboratory-West
Argonne National Laboratory-West (ANL-W) has approximately 680,000 liters of raw sodium stored in facilities on site. As mandated by the State of Idaho and the US Department of Energy (DOE), this sodium must be transformed into a stable condition for land disposal. To comply with this mandate, ANL-W designed and built the Sodium Process Facility (SPF) for the processing of this sodium into a dry, sodium carbonate powder. The major portion of the sodium stored at ANL-W is radioactively contaminated. The sodium will be processed in three separate and distinct campaigns: the 290,000 liters of Fermi-1 primary sodium, the 50,000 liters of the Experimental Breeder Reactor-II (EBR-II) secondary sodium, and the 330,000 liters of the EBR-II primary sodium. The Fermi-1 and the EBR-II secondary sodium contain only low-level of radiation, while the EBR-II primary sodium has radiation levels up to 0.5 mSv (50 mrem) per hour at 1 meter. The EBR-II primary sodium will be processed last, allowing the operating experience to be gained with the less radioactive sodium prior to reacting the most radioactive sodium. The sodium carbonate will be disposed of in 270 liter barrels, four to a pallet. These barrels are square in cross-section, allowing for maximum utilization of the space on a pallet, minimizing the required landfill space required for disposal.
Michelbacher, J.A.; Henslee, S.P. McDermott, M.D.; Price, J.R.; Rosenberg, K.E.; Wells, P.B.
Method and system for producing hydrogen using sodium ion separation membranes
A method of producing hydrogen from sodium hydroxide and water is disclosed. The method comprises separating sodium from a first aqueous sodium hydroxide stream in a sodium ion separator, feeding the sodium produced in the sodium ion separator to a sodium reactor, reacting the sodium in the sodium reactor with water, and producing a second aqueous sodium hydroxide stream and hydrogen. The method may also comprise reusing the second aqueous sodium hydroxide stream by combining the second aqueous sodium hydroxide stream with the first aqueous sodium hydroxide stream. A system of producing hydrogen is also disclosed.
Bingham, Dennis N; Klingler, Kerry M; Turner, Terry D; Wilding, Bruce M; Frost, Lyman
Silica recovery and control in Hawaiian geothermal fluids
A series of experiments was performed to investigate methods of controlling silica in waste geothermal brines produced at the HGP-A Generator Facility. Laboratory testing has shown that the rate of polymerization of silica in the geothermal fluids is highly pH dependent. At brine pH values in excess of 8.5 the suspension of silica polymers flocculated and rapidly precipitated a gelatinous silica mass. Optimum flocculation and precipitation rates were achieved at pH values in the range of 10.5 to 11.5. The addition of transition metal salts to the geothermal fluids similarly increased the rate of polymerization as well as the degree of precipitation of the silica polymer from suspension. A series of experiments performed on the recovered silica solids demonstrated that methanol extraction of the water in the gels followed by critical point drying yielded surface areas in excess of 300 M{sup 2}/g and that treatment of the dried solids with 2 N HCl removed most of the adsorbed impurities in the recovered product. A series of experiments tested the response of the waste brines to mixing with steam condensate and non-condensable gases.The results demonstrated that the addition of condensate and NCG greatly increased the stability of the silica in the geothermal brines. They also indicated that the process could reduce the potential for plugging of reinjection wells receiving waste geothermal fluids from commercial geothermal facilities in Hawaii. Conceptual designs were proposed to apply the gas re-combination approach to the disposal of geothermal waste fluids having a range of chemical compositions. Finally, these designs were applied to the geothermal fluid compositions found at Cerro Prieto, Ahuachapan, and Salton Sea.
Thomas, D.M.
Silica recovery and control in Hawaiian geothermal fluids. Final report
Further Investigations of the Effect of Replacing Lithium by Sodium on Lithium Silicate Scintillating Glass Efficiency
Ce3+ doped lithium (6Li) silicate glasses are thermal neutron detectors. Prior work showed that when sodium (Na) is substituted for Li the scintillation efficiency, under beta particle stimulation, increased and then decreased as the sodium (Na) content was increased [1]. When all the 6Li was replaced by Na no scintillation was observed. Raman spectra, acquired using a visible excitation source provided no evidence of anomalous behavior. SEM microscopy did show some phase separation, but there was no obvious correlation with the scintillation efficiency. We have reexamined these glass samples using deep UV Raman excitation which reduces fluorescence interference. The newly acquired spectra show evidence of phase separation in the glasses. Specifically we see a peak at 800 cm-1 Raman shift which can be assigned to a vitreous silica moiety that results from phase separation. There is a strong correlation between this peak's area, the scintillation efficiency, and the Na content. The observed trend suggests that phase separation enhances scintillation and addition of Na reduces the amount of phase separation. We also see evidence of at least two defect structures that can be tentatively assigned to a three-membered ring structure and an oxygen vacancy. The latter is fairly strongly correlated with enhanced scintillation efficiency.
Bliss, Mary; Aker, Pamela M.; Windisch, Charles F.
Temperature and moisture dependence of dielectric constant for silica aerogels
The dielectric constants of silica aerogels are among the lowest measured for any solid material. The silica aerogels also exhibit low thermal expansion and are thermally stable to temperatures exceeding 500{degrees}C. However, due to the open porosity and large surface areas for aerogels, their dielectric constants are strongly affected by moisture and temperature. This paper presents data for the dielectric constants of silica aerogels as a function of moisture content at 25{degrees}C, and as a function of temperature, for temperatures in the range from 25{degrees}C to 450{degrees}C. Dielectric constant data are also given for silica aerogels that are heat treated in dry nitrogen at 500{degrees}C, then cooled to 25{degrees}C for measurements in dry air. All measurements are made on bulk aerogel spheres at 22GHz microwave frequency, using a cavity perturbation method. The results of the dependence found here for bulk materials can be inferred to apply also to thin films of silica aerogels having similar nano-structures and densities.
Hrubesh, L.H., LLNL
Surface characterization of silica glass substrates treated by atomic hydrogen
Silica glass substrates with very flat surfaces were exposed to atomic hydrogen at different temperatures and durations. An atomic force microscope was used to measure root-mean-square (RMS) roughness and two-dimensional power spectral density (PSD). In the treatment with atomic hydrogen up to 900 �C, there was no significant change in the surface. By the treatment at 1000 �C, the changes in the RMS roughness and the PSD curves were observed. It was suggested that these changes were caused by etching due to reactions of atomic hydrogen with surface silica. By analysis based on the k-correlation model, it was found that the spatial frequency of the asperities became higher with an increase of the treatment time. Furthermore, the data showed that atomic hydrogen can flatten silica glass surfaces by controlling heat-treatment conditions. - Highlights: � Silica glass surface was treated by atomic hydrogen at various temperatures. � Surface roughness was measured by an atomic force microscope. � Roughness data were analyzed by two-dimensional power spectral density. � Atomic hydrogen can flatten silica glass surfaces.
Inoue, Hiroyuki [Institute of Industrial Science, The University of Tokyo, Meguro-ku, Tokyo 153-8505 (Japan); Masuno, Atsunobu, E-mail: email@example.com [Institute of Industrial Science, The University of Tokyo, Meguro-ku, Tokyo 153-8505 (Japan); Ishibashi, Keiji [Canon ANELVA Corporation, Asao-ku, Kawasaki, Kanagawa 215-8550 (Japan); Tawarayama, Hiromasa [Kawazoe Frontier Technologies Corporation, Kuden 931-113, Sakae-ku, Yokohama, Kanagawa 247-0014 (Japan); Zhang, Yingjiu; Utsuno, Futoshi [Institute of Industrial Science, The University of Tokyo, Meguro-ku, Tokyo 153-8505 (Japan); Koya, Kazuo; Fujinoki, Akira [Shin Etsu Quartz Prod. Co., Ltd., Res and Applicat Lab, Fukushima 963-0725 (Japan); Kawazoe, Hiroshi [Kawazoe Frontier Technologies Corporation, Kuden 931-113, Sakae-ku, Yokohama, Kanagawa 247-0014 (Japan)
Vanadyl tert-Butoxy Orthosilicate, OV[OSi(OtBu)3]3: A Model for Isolated Vanadyl Sites on Silica and a
-containing silica aerogels and xerogels.13-17 In addition, vanadia-silica catalysts have been prepared by treating
Iglesia, Enrique
Silica membranes for hydrogen separation from coal gas. Final report
This project is a continuation of a previous DOE-UCR project (DE-FG22- 89PC89765) dealing with the preparation of silica membranes highly permselective to hydrogen at elevated temperatures, suitable for hydrogen separation from coal gas. The membranes prepared in the previous project had very high selectivity but relatively low permeance. Therefore, the general objectives of this project were to improve the permeance of these membranes and to obtain fundamental information about membrane structure and properties. The specific objectives were: (1) to explore new silylation reagents and reaction conditions with the purpose of reducing the thickness and increasing the permeance of silica membranes prepared by chemical vapor deposition (CVD), (2) to characterize the membrane structure, (3) to delineate mechanism and kinetics of deposition, (4) to measure the permeability of silica layers at different extents of deposition, and (5) to mathematically model the relationship between structure and deposition kinetics.
Gavalas, G.R.
E-Print Network 3.0 - aqueous silica sols Sample Search Results
by supercritical CO2 extraction of silica sol-gels.14 But the very high porosity in aerogels contributes... Silica Monoliths Templated on L3 Liquid Crystal Abds-Sami Malik,,...
Experimental Simulation of Evaporation-Driven Silica Sinter Formation and Microbial Silicification in Hot Spring Systems
in geothermal waters after they have reached the surface. Water evaporation is, along with cooling, one Evaporation of silica-rich geothermal waters is one of the main abiotic drivers of the formation of silica
Paris-Sud XI, Université de
Evaluation and recommendations for reduction of a silica dust exposure
to the increase in active tuberculosis among silicotics previously discussed. Perhaps there is a synergistic effect between silicosis and various lung cancers. A 1999 paper by Checkoway("6) showed a significantly (p=0. 02) increasing trend of lung cancer..., and that 100, 000 are exposed to silica dust through sandblasting, rock drilling and mining operations. &sI Silica is the second- most-common mineral in the earth's crust and a major component of sand, rock and mineral ores so it is not surprising to find...
Gruben, Raymond L
In sodium tests of ultrasonic transducers
Ultrasonic techniques are seen as suitable candidates for the in-service inspection and for the continuous surveillance of sodium cooled reactors (SFR). These techniques need the development and the qualification of immersed ultrasonic transducers, and materials. This paper presents some developments performed by CEA (DTN and LIST) and AREVA (NDE Solutions), and some results. (authors)
Lhuillier, C.; Descombin, O.; Baque, F. [CEA, DTN, 13108 Saint Paul lez Durance Cedex (France); Marchand, B. [CEA, LIST, 91191 Gif-sur-Yvette (France); Saillant, J. F. [AREVA/NDE Solutions, 4 rue Thomas Dumorey, 71109 Chalon sur Saone Cedex (France); Augem, J. M. [EDF, 12-14 avenue Dutrievoz, 69628 Villeurbanne (France)
Project EARTH-11-RR4: Reconstructing the Cenozoic Silica Cycle using Sponge 30
to the oceans and the success of the diatoms. Although diversity curves suggest that diatoms radiated concident. The radiation of siliceous diatoms during the Cenozoic is thought to have forced the ocean from a high silica.e. enhanced silicate weathering due to the radiation of grasses on land drove increased silica supply
Henderson, Gideon
Hierarchical Silica Nanostructures Inspired by Diatom Algae Yield Superior Deformability, Toughness, and Strength
Hierarchical Silica Nanostructures Inspired by Diatom Algae Yield Superior Deformability, Toughness algae that is mainly composed of amorphous silica, which features a hierarchical structure that ranges in diatom algae as a basis to study a bioinspired nanoporous material implemented in crystalline silica. We
Buehler, Markus J.
Analysis of the elastic behaviour of silica aerogels taken as a percolating system
289 Analysis of the elastic behaviour of silica aerogels taken as a percolating system T. Woignier of silica aerogels are performed using the three points flexural technique. The elastic behaviour is studied measurement - for silica aerogels. These highly porous materials are obtained from a sol-gel process. Solvent
Multicomponent Transport of Sulfate in a Goethite-Silica Sand System
Multicomponent Transport of Sulfate in a Goethite-Silica Sand System at Variable pH and Ionic of protons and sulfate on goethite and silica were used in combination with a one-dimensional mass-transport model to predict the transport of sulfate at variable pH and ionic strength in a goethite-silica system
Sparks, Donald L.
Gypsum and Polyacrylamide Soil Amendments Used With High Sodium Wastewater
Using wastewater for irrigation of crops represents an attractive alternative to disposal. Typically, municipal wastewaters are high in sodium, and the resulting high sodium absorption ratio (SAR) alters the soil structure making it more impermeable...
Gardiner, Duane
Sodium and sulfur release and recapture during black liquor burning
The objective of this study was to provide data on sulfur and sodium volatilization during black liquor burning, and on SO2 capture by solid sodium carbonate and sodium chloride. This data was interpreted and modeled into rate equations suitable for use in computational models for recovery boilers.
Frederick, W.J.; Iisa, K.; Wag, K.; Reis, V.V.; Boonsongsup, L.; Forssen, M.; Hupa, M.
Silica dust control when drilling concrete Page 1 of 2
Silica dust control when drilling concrete Page 1 of 2 Drilling into concrete releases a fine sandy and routinely drill into concrete are at risk of developing this disease. Controlling the dust Hammer drills are available with attached dust removal systems. These draw dust from the drill end, down the attachment
Knowles, David William
High temperature thermographic measurements of laser heated silica
In situ spatial and temporal surface temperature profiles of CO{sub 2} laser-heated silica were obtained using a long wave infrared (LWIR) HgCdTe camera. Solutions to the linear diffusion equation with volumetric and surface heating are shown to describe the temperature evolution for a range of beam powers, over which the peak surface temperature scales linearly with power. These solutions were used with on-axis steady state and transient experimental temperatures to extract thermal diffusivity and conductivity for a variety of materials, including silica, spinel, sapphire, and lithium fluoride. Experimentally-derived thermal properties agreed well with reported values and, for silica, thermal conductivity and diffusivity are shown to be approximately independent of temperature between 300 and 2800K. While for silica our analysis based on a temperature independent thermal conductivity is shown to be accurate, for other materials studied this treatment yields effective thermal properties that represent reasonable approximations for laser heating. Implementation of a single-wavelength radiation measurement in the semi-transparent regime is generally discussed, and estimates of the apparent temperature deviation from the actual outer surface temperature are also presented. The experimental approach and the simple analysis presented yield surface temperature measurements that can be used to validate more complex physical models, help discriminate dominant heat transport mechanisms, and to predict temperature distribution and evolution during laser-based material processing.
Elhadj, S; Yang, S T; Matthews, M J; Cooke, D J; Bude, J D; Johnson, M; Feit, M; Draggoo, V; Bisson, S E
Fractal Studies on Titanium-Silica Aerogels using SMARTer
Power-law scattering approximation has been employed to reveal the fractal structures of solid-state titanium-silica aerogel samples. All small-angle neutron scattering (SANS) measurements were performed using 36 meters SANS BATAN spectrometer (SMARTer) at the neutron scattering laboratory (NSL) in Serpong, Indonesia. The mass fractal dimension of titanium-silica aerogels at low scattering vector q range increases from -1.4 to -1.92 with the decrease of acid concentrations during sol-gel process. These results are attributed to the titanium-silica aerogels that are growing to more polymeric and branched structures. At high scattering vector q range the Porod slope of -3.9 significantly down to -2.24 as the roughness of particle surfaces becomes higher. The cross over between these two regimes decreases from 0.4 to 0.16 nm{sup -1} with the increase of acid concentrations indicating also that the titanium-silica aerogels are growing.
Putra, E. Giri Rachman; Ikram, A.; Bharoto; Santoso, E. [Neutron Scattering Laboratory, BATAN, Kawasan Puspiptek Serpong, Tangerang 15314 (Indonesia); Fang, T. Chiar; Ibrahim, N. [Department of Physics, Faculty of Science Universiti Teknologi Malaysia (UTM), 81310 Skudai, Johor (Malaysia); Mohamed, A. Aziz [Materials Technology Group, Industrial Technology Division Agensi Nuklear Malaysia, 43000 Kajang (Malaysia)
Spatial Pattern Formation in Fused Silica Under UV Irradiation
Spatial Pattern Formation in Fused Silica Under UV Irradiation Problem Presenter Leslie Button lenses gradually degrades and ultimately damages these optical components. Corning is a global supplier of optical and ceramic materials across various industries and is particularly interested in this damage
Edwards, David A.
Development of Silica/Vanadia/ Titania Catalysts for Removal of
mercury (Hg0) from simulated coal-combustion flue gas. Experiments were carried out in fixed-bed reactorsDevelopment of Silica/Vanadia/ Titania Catalysts for Removal of Elemental Mercury from Coal-Combustion the composition and microstructures of SCR (selective catalytic reduction) catalysts for Hg0 oxidation in coal-combustion
Li, Ying
Moisture Transport in Silica Gel Packed Beds: II. Experimental Study
Experiments have been performed to obtain the transient response of a thin adiabatic packed bed of silica gel after a step change in inlet air conditions, comparisons are made with predictions using a solid-side resistance model and a pseudo-gas-side controlled model and better agreement obtained with the former model.
Pesaran, A. A.; Mills, A. F.
Corrosion performance of advanced structural materials in sodium.
This report gives a description of the activities in design, fabrication, construction, and assembling of a pumped sodium loop for the sodium compatibility studies on advanced structural materials. The work is the Argonne National Laboratory (ANL) portion of the effort on the work project entitled, 'Sodium Compatibility of Advanced Fast Reactor Materials,' and is a part of Advanced Materials Development within the Reactor Campaign. The objective of this project is to develop information on sodium corrosion compatibility of advanced materials being considered for sodium reactor applications. This report gives the status of the sodium pumped loop at Argonne National Laboratory, the specimen details, and the technical approach to evaluate the sodium compatibility of advanced structural alloys. This report is a deliverable from ANL in FY2010 (M2GAN10SF050302) under the work package G-AN10SF0503 'Sodium Compatibility of Advanced Fast Reactor Materials.' Two reports were issued in 2009 (Natesan and Meimei Li 2009, Natesan et al. 2009) which examined the thermodynamic and kinetic factors involved in the purity of liquid sodium coolant for sodium reactor applications as well as the design specifications for the ANL pumped loop for testing advanced structural materials. Available information was presented on solubility of several metallic and nonmetallic elements along with a discussion of the possible mechanisms for the accumulation of impurities in sodium. That report concluded that the solubility of many metals in sodium is low (<1 part per million) in the temperature range of interest in sodium reactors and such trace amounts would not impact the mechanical integrity of structural materials and components. The earlier report also analyzed the solubility and transport mechanisms of nonmetallic elements such as oxygen, nitrogen, carbon, and hydrogen in laboratory sodium loops and in reactor systems such as Experimental Breeder Reactor-II, Fast Flux Test Facility, and Clinch River Breeder Reactor. Among the nonmetallic elements discussed, oxygen is deemed controllable and its concentration in sodium can be maintained in sodium for long reactor life by using cold-trap method. It was concluded that among the cold-trap and getter-trap methods, the use of cold trap is sufficient to achieve oxygen concentration of the order of 1 part per million. Under these oxygen conditions in sodium, the corrosion performance of structural materials such as austenitic stainless steels and ferritic steels will be acceptable at a maximum core outlet sodium temperature of {approx}550 C. In the current sodium compatibility studies, the oxygen concentration in sodium will be controlled and maintained at {approx}1 ppm by controlling the cold trap temperature. The oxygen concentration in sodium in the forced convection sodium loop will be controlled and monitored by maintaining the cold trap temperature in the range of 120-150 C, which would result in oxygen concentration in the range of 1-2 ppm. Uniaxial tensile specimens are being exposed to flowing sodium and will be retrieved and analyzed for corrosion and post-exposure tensile properties. Advanced materials for sodium exposure include austenitic alloy HT-UPS and ferritic-martensitic steels modified 9Cr-1Mo and NF616. Among the nonmetallic elements in sodium, carbon was assessed to have the most influence on structural materials since carbon, as an impurity, is not amenable to control and maintenance by any of the simple purification methods. The dynamic equilibrium value for carbon in sodium systems is dependent on several factors, details of which were discussed in the earlier report. The current sodium compatibility studies will examine the role of carbon concentration in sodium on the carburization-decarburization of advanced structural materials at temperatures up to 650 C. Carbon will be added to the sodium by exposure of carbon-filled iron tubes, which over time will enable carbon to diffuse through iron and dissolve into sodium. The method enables addition of dissolved carbon (without carb
Natesan, K.; Momozaki, Y.; Li, M.; Rink, D.L. (Nuclear Engineering Division)
Flue gas injection control of silica in cooling towers.
Injection of CO{sub 2}-laden flue gas can decrease the potential for silica and calcite scale formation in cooling tower blowdown by lowering solution pH to decrease equilibrium calcite solubility and kinetic rates of silica polymerization. Flue gas injection might best inhibit scale formation in power plant cooling towers that use impaired makeup waters - for example, groundwaters that contain relatively high levels of calcium, alkalinity, and silica. Groundwaters brought to the surface for cooling will degas CO{sub 2} and increase their pH by 1-2 units, possibly precipitating calcite in the process. Recarbonation with flue gas can lower the pHs of these fluids back to roughly their initial pH. Flue gas carbonation probably cannot lower pHs to much below pH 6 because the pHs of impaired waters, once outgassed at the surface, are likely to be relatively alkaline. Silica polymerization to form scale occurs most rapidly at pH {approx} 8.3 at 25 C; polymerization is slower at higher and lower pH. pH 7 fluids containing {approx}220 ppm SiO{sub 2} require > 180 hours equilibration to begin forming scale whereas at pH 8.3 scale formation is complete within 36 hours. Flue gas injection that lowers pHs to {approx} 7 should allow substantially higher concentration factors. Periodic cycling to lower recoveries - hence lower silica concentrations - might be required though. Higher concentration factors enabled by flue gas injection should decrease concentrate volumes and disposal costs by roughly half.
Brady, Patrick Vane; Anderson, Howard L., Jr.; Altman, Susan Jeanne
INSTRUMENTS-METHODS-36 Absorption and scattering lengths of high density silica aerogels with n = 1.07
angles could be the use of silica aerogels as radiator. Simultaneously, an aerogel ?erenkov counter is
L. Debenjak; P. Achenbach; J. Pochodzalla; T. Saito
Cast Stone Formulation At Higher Sodium Concentrations
A low temperature waste form known as Cast Stone is being considered to provide supplemental Low Activity Waste (LAW) immobilization capacity for the Hanford site. Formulation of Cast Stone at high sodium concentrations is of interest since a significant reduction in the necessary volume of Cast Stone and subsequent disposal costs could be achieved if an acceptable waste form can be produced with a high sodium molarity salt solution combined with a high water to premix (or dry blend) ratio. The objectives of this study were to evaluate the factors involved with increasing the sodium concentration in Cast Stone, including production and performance properties and the retention and release of specific components of interest. Three factors were identified for the experimental matrix: the concentration of sodium in the simulated salt solution, the water to premix ratio, and the blast furnace slag portion of the premix. The salt solution simulants used in this study were formulated to represent the overall average waste composition. The cement, blast furnace slag, and fly ash were sourced from a supplier in the Hanford area in order to be representative. The test mixes were prepared in the laboratory and fresh properties were measured. Fresh density increased with increasing sodium molarity and with decreasing water to premix ratio, as expected given the individual densities of these components. Rheology measurements showed that all of the test mixes produced very fluid slurries. The fresh density and rheology data are of potential value in designing a future Cast Stone production facility. Standing water and density gradient testing showed that settling is not of particular concern for the high sodium compositions studied. Heat of hydration measurements may provide some insight into the reactions that occur within the test mixes, which may in turn be related to the properties and performance of the waste form. These measurements showed that increased sodium concentration in the salt solution reduced the time to peak heat flow, and reducing the amount of slag in the premix increased the time to peak heat flow. These observations may help to describe some of the cured properties of the samples, in particular the differences in compressive strength observed after 28 and 90 days of curing. Samples were cured for at least 28 days at ambient temperature in the laboratory prior to cured properties analyses. The low activity waste form for disposal at the Hanford Site is required to have a compressive strength of at least 500 psi. After 28 days of curing, several of the test mixes had mean compressive strengths that were below the 500 psi requirement. Higher sodium concentrations and higher water to premix ratios led to reduced compressive strength. Higher fly ash concentrations decreased the compressive strength after 28 days of curing. This may be explained in that the cementitious phases matured more quickly in the mixes with higher concentrations of slag, as evidenced by the data for the time to peak heat generation. All of the test mixes exhibited higher mean compressive strengths after 90 days of curing, with only one composition having a mean compressive strength of less than 500 psi. Leachability indices were determined for the test mixes for contaminants of interest. The leaching performance of the mixes evaluated in this study was not particularly sensitive to the factors used in the experimental design. This may be beneficial in demonstrating that the performance of the waste form is robust with respect to changes in the mix composition. The results of this study demonstrate the potential to achieve significantly higher waste loadings in Cast Stone and other low temperature, cementitious waste forms. Additional work is needed to elucidate the hydration mechanisms occurring in Cast Stone formulated with highly concentrated salt solutions since these reactions are responsible for determining the performance of the cured waste form. The thermal analyses completed in this study provide some preliminary insight, although the l
Fox, K. M.; Roberts, K. A.; Edwards, T. B.
A low temperature waste form known as Cast Stone is being considered to provide supplemental Low Activity Waste (LAW) immobilization capacity for the Hanford site. Formulation of Cast Stone at high sodium concentrations is of interest since a significant reduction in the necessary volume of Cast Stone and subsequent disposal costs could be achieved if an acceptable waste form can be produced with a high sodium molarity salt solution combined with a high water to premix (or dry blend) ratio. The objectives of this study were to evaluate the factors involved with increasing the sodium concentration in Cast Stone, including production and performance properties and the retention and release of specific components of interest. Three factors were identified for the experimental matrix: the concentration of sodium in the simulated salt solution, the water to premix ratio, and the blast furnace slag portion of the premix. The salt solution simulants used in this study were formulated to represent the overall average waste composition. The cement, blast furnace slag, and fly ash were sourced from a supplier in the Hanford area in order to be representative. The test mixes were prepared in the laboratory and fresh properties were measured. Fresh density increased with increasing sodium molarity and with decreasing water to premix ratio, as expected given the individual densities of these components. Rheology measurements showed that all of the test mixes produced very fluid slurries. The fresh density and rheology data are of potential value in designing a future Cast Stone production facility. Standing water and density gradient testing showed that settling is not of particular concern for the high sodium compositions studied. Heat of hydration measurements may provide some insight into the reactions that occur within the test mixes, which may in turn be related to the properties and performance of the waste form. These measurements showed that increased sodium concentration in the salt solution reduced the time to peak heat flow, and reducing the amount of slag in the premix increased the time to peak heat flow. These observations may help to describe some of the cured properties of the samples, in particular the differences in compressive strength observed after 28 and 90 days of curing. Samples were cured for at least 28 days at ambient temperature in the laboratory prior to cured properties analyses. The low activity waste form for disposal at the Hanford Site is required to have a compressive strength of at least 500 psi. After 28 days of curing, several of the test mixes had mean compressive strengths that were below the 500 psi requirement. Higher sodium concentrations and higher water to premix ratios led to reduced compressive strength. Higher fly ash concentrations decreased the compressive strength after 28 days of curing. This may be explained in that the cementitious phases matured more quickly in the mixes with higher concentrations of slag, as evidenced by the data for the time to peak heat generation. All of the test mixes exhibited higher mean compressive strengths after 90 days of curing, with only one composition having a mean compressive strength of less than 500 psi. Leach indices were determined for the test mixes for contaminants of interest. The leaching performance of the mixes evaluated in this study was not particularly sensitive to the factors used in the experimental design. This may be beneficial in demonstrating that the performance of the waste form is robust with respect to changes in the mix composition. The results of this study demonstrate the potential to achieve significantly higher waste loadings in Cast Stone and other low temperature, cementitious waste forms. Additional work is needed to elucidate the hydration mechanisms occurring in Cast Stone formulated with highly concentrated salt solutions since these reactions are responsible for determining the performance of the cured waste form. The thermal analyses completed in this study provide some preliminary insight, although the limited
Fox, K. M.; Edwards, T. A.; Roberts, K. B.
Acid/Base Recovery From Sodium Sulfate
escalating In price due to the Imbalance In market demand. Chlorine and caustic are produced together by the electrolysis 01 sodium chloride brine solutions. Every ECU (electrochemical unit) 01 chlorine resu~s In the production 01 one ECU 01 caustic soda... cell also produces an acid product that is contaminated with unreacted sullate. The voltage 01 a three compartment is higher, however, and the process system Is more complex. Process System Current density and efficiency determines the amount 01...
Niksa, M. J.
Recent Sodium Technology Development for the Decommissioning of the Rapsodie and Superphenix Reactors and the Management of Sodium Wastes
The Commissariat a l'Energie Atomique (CEA) has recently developed and/or conducted experiments on several processes in support of the decommissioning of two French liquid-metal fast reactors (LMFRs), Rapsodie and Superphenix, as well as on the treatment of CEA sodium wastes. CEA has demonstrated that it is possible to define appropriate and efficient processes to meet the different situations encountered in decommissioning LMFRs. Mechanical techniques derived from standard technologies have been successfully applied to fast reactor decommissioning to complete primary vessel draining from sodium. In addition, specific chemical processes have been developed to deal safely with metallic sodium reactivity. Sodium-contaminated equipment has been successfully cleaned by reacting sodium with water mist in an atmosphere with carbon dioxide to form inert sodium carbonate. Bulk sodium has been successfully converted into aqueous caustic soda by injection of liquid-metallic sodium into sodium hydroxide solution. Several processes were also defined to deal with specific sodium wastes. In all cases the principle is based on a sodium/water chemical reaction where the released hydrogen and heat are controlled. With the development of a wide variety of processes, all steps in the decommissioning of LMFRs are assumed to be now properly mastered.
Rodriguez, G.; Gastaldi, O.; Baque, F. [Commissariat a l'Energie Atomique Cadarache (France)
Report on sodium compatibility of advanced structural materials.
This report provides an update on the evaluation of sodium compatibility of advanced structural materials. The report is a deliverable (level 3) in FY11 (M3A11AN04030403), under the Work Package A-11AN040304, 'Sodium Compatibility of Advanced Structural Materials' performed by Argonne National Laboratory (ANL), as part of Advanced Structural Materials Program for the Advanced Reactor Concepts. This work package supports the advanced structural materials development by providing corrosion and tensile data from the standpoint of sodium compatibility of advanced structural alloys. The scope of work involves exposure of advanced structural alloys such as G92, mod.9Cr-1Mo (G91) ferritic-martensitic steels and HT-UPS austenitic stainless steels to a flowing sodium environment with controlled impurity concentrations. The exposed specimens are analyzed for their corrosion performance, microstructural changes, and tensile behavior. Previous reports examined the thermodynamic and kinetic factors involved in the purity of liquid sodium coolant for sodium reactor applications as well as the design, fabrication, and construction of a forced convection sodium loop for sodium compatibility studies of advanced materials. This report presents the results on corrosion performance, microstructure, and tensile properties of advanced ferritic-martensitic and austenitic alloys exposed to liquid sodium at 550 C for up to 2700 h and at 650 C for up to 5064 h in the forced convection sodium loop. The oxygen content of sodium was controlled by the cold-trapping method to achieve {approx}1 wppm oxygen level. Four alloys were examined, G92 in the normalized and tempered condition (H1 G92), G92 in the cold-rolled condition (H2 G92), G91 in the normalized and tempered condition, and hot-rolled HT-UPS. G91 was included as a reference to compare with advanced alloy, G92. It was found that all four alloys showed weight loss after sodium exposures at 550 and 650 C. The weight loss of the four alloys was comparable after sodium exposures at 550 C; the weight loss of ferritic-martensitic steels, G92 and G91 is more significant than that of austenitic stainless steel, HT-UPS after sodium exposures at 650 C. Sodium exposures up to 2700 h at 550 C had no significant influence on tensile properties, while sodium exposures up to 5064 h at 650 C dramatically lowered the tensile strengths of the four alloys. The ultimate tensile strength of H1 G92, H2 G92, and G91 ferritic-martensitic steels was reduced to as much as nearly half of its initial value after sodium exposures at 650 C. Though the uniform elongation was recovered to some extent, these three ferritic-martensitic steels showed considerable strain softening after sodium exposures. The yield stress of HT-UPS austenitic stainless steel increased, the ultimate tensile strength decreased, and the total elongation was reduced after sodium exposures at 650 C. The dynamic strain aging effect observed in the as-received HT-UPS specimens became less pronounced after sodium exposures at 650 C. Microstructural characterization of sodium-exposed specimens showed no appreciable surface deterioration or grain structure changes under an optical microscope, except for the H2 G92 steel, in which the martensite structure transformed to large grain ferrite after sodium exposures at 650 C. TEM observations of the sodium-exposed H2 G92 steel showed significant recrystallization after sodium exposure for 2700 h at 550 C, and transformation of martensite to ferrite and high density of precipitates in nearly dislocation-free matrix after sodium exposures at 650 C. Further microstructural analysis and evaluation of decarburization/carburization behavior is needed to understand the dramatic changes in the tensile strengths of advanced ferritic-martensitic and austenitic steels after sodium exposures at 650 C.
Li, M.; Natesan, K.; Momozaki, Y.; Rink, D.L.; Soppet, W.K.; Listwan, J.T. (Nuclear Engineering Division)
Factors contributing to the breakdown of sodium beta-alumina
Clarification of the breakdown process occurring during charge transfer in sodium beta alumina solid electrolytes was derived from: (1) studying the effects of molten sodium contact at 350/sup 0/C on single crystal sodium beta alumina and polycrystalline sodium beta alumina; (2) determination of critical current density by monitoring acoustic emissions accompanying crack growth in sodium/sodium beta alumina/sodium cells subjected to linear current ramping at 1 mA cm/sup -2/ sec/sup -1/; (3) failure analysis conducted on cycled electrolytes, some from commercial sodium/sulfur cells, which had been subjected to up to 703 Ahr cm/sup -2/ of charge transfer. Gray coloration developing in beta aluminas in contact with molten sodium was found to be a consequence of formation, through reduction by sodium, of oxygen vacancies charge compensated by electrons. Electronic conductivity of the electrolyte increases as a result. No second phase formation was detected. Colored electrolytes from sodium/sulfur cells show evidence of a newly recognized degradation mechanism in which fracture occurs when sodium is reduced and deposited internally under pressure as metal in regions where an electronic conductivity gradient exists. Heating colored beta aluminas in air produces reoxidation and bleaching. Kinetics and other properties of the coloration and bleaching processes were determined. Critical current density was found to bear an inverse relation to average electrolyte grain size. Evidence was found in the cycled electrolytes for a slow crack growth mechanism and a progressive mode of degradation advancing from the sulfur electrode interface. Implications of the findings for the construction and operation of sodium/sulfur battery systems are discussed.
Buechele, A.C.
Fluorescent Functionalized Mesoporous Silica for Radioactive Material Extraction
Mesoporous silica with covalently bound salicylic acid molecules incorporated in the structure was synthesized with a one-pot, co-condensation reaction at room temperature. The as-synthesized material has a large surface area, uniform particle size, and an ordered pore structure as determined by characterization with transmission electron microscopy, thermal gravimetric analysis, and infrared spectra, etc. Using the strong fluorescence and metal coordination capability of salicylic acid, functionalized mesoporous silica (FMS) was developed to track and extract radionuclide contaminants, such as uranyl [U(VI)] ions encountered in subsurface environments. Adsorption measurements showed a strong affinity of the FMS toward U(VI) with a Kd value of 105 mL/g, which is four orders of magnitude higher than the adsorption of U(VI) onto most of the sediments in natural environments. The new materials have a potential for synergistic environmental monitoring and remediation of the radionuclide U(VI) from contaminated subsurface environments.
Li, Juan; Zhu, Kake; Shang, Jianying; Wang, Donghai; Nie, Zimin; Guo, Ruisong; Liu, Chongxuan; Wang, Zheming; Li, Xiaolin; Liu, Jun
Silica aerogels modified by functional and nonfunctional organic groups
Organically substituted silica aerogels were prepared from RSi(OR`){sub 3}/Si(OR`){sub 4} mixtures, followed by supercritical drying. The typical microstructure and the resulting physical properties of silica aerogels are retained, if the portion of R-Si units is below 10-20%. However, new properties are supplemented, such as hydrophobicity (which makes the aerogels insensitive towards moisture), a higher compliance, and the possibility to incorporate functional organic groups. Controlled pyrolysis of the organically substituted aerogels allows to coat the inner surface of the aerogels with nanometer-sized carbon structures. This results in a very efficient infrared opacification and improved heat insulation properties at high temperatures. 5 refs., 2 figs.
Schubert, U.; Huesing, N.; Schwertfeger, F. [Universitaet Wien (Austria)
Mineral scale depositation occurs in many of the Cerro Prieto wells, but the main problems occurs by silica (SiO2) scale both pipes and reservoir zones close to the downhole. In Cerro Prieto geothermal field three types of scales are found; calcium carbonate (calcite), amorphous silica (SiO2), and metallic sulfides (mainly iron, and lesser lead and cooper). The scale causes lost production and it is necessary to make around 12 workover each year to recover the steam lost. When scaling problems occurred inside casing production is more easier to recover the production that scaling occurred in the reservoir zones, because it caused a skin damage (permeability decrease) in the reservoir zones close to the bottomhole. This paper analyze and discus the scaling problems and discuss the task developed to avoid and minimized the decline wells production, as to recover the production using workover alternatives.
Prieto Geothermal; Wells Mexico; Juan De; Dios Ocampo; D�az Sara; Lilia Moya; Jes�s De; Le�n Vivar
Molecular engineering of porous silica using aryl templates
A process is described for manipulating the porosity of silica using a series of organic template groups covalently incorporated into the silicate matrix. The templates in the bridged polysilsesquioxanes are selectively removed from the material by oxidation with oxygen plasma or other means, leaving engineered voids or pores. The size of these pores is dependent upon the length or size of the template or spacer. The size of the templates is measured in terms of Si-Si distances which range from about 0.67 nm to 1.08 nm. Changes introduced by the loss of the templates result in a narrow range of micropores (i.e. <2 nm). Both aryl and alkyl template groups are used as spacers. Novel microporous silica materials useful as molecular sieves, desiccants, and catalyst supports are produced. 3 figs.
Loy, D.A.; Shea, K.J.
A process for manipulating the porosity of silica using a series of organic template groups covalently incorporated into the silicate matrix. The templates in the bridged polysilsesquioxanes are selectively removed from the material by oxidation with oxygen plasma or other means, leaving engineered voids or pores. The size of these pores is dependent upon the length or size of the template or spacer. The size of the templates is measured in terms of Si-Si distances which range from about 0.67 nm to 1.08 nm. Changes introduced by the loss of the templates result in a narrow range of micropores (i.e. <2 nm). Both aryl and alkyl template groups are used as spacers. Novel microporous silica materials useful as molecular seives, dessicants, and catalyst supports are produced.
Loy, Douglas A. (Albuquerque, NM); Shea, Kenneth J. (Irvine, CA)
Supercritical carbon dioxide behavior in porous silica aerogel
Analysis of the tails of the small-angle neutron scattering (SANS) intensities relevant to samples formed by porous silica and carbon dioxide at pressures ranging from 0 to 20 MPa and at temperatures of 308 and 353 K confirms that the CO2 fluid must be treated as a two-phase system. The first of these phases is formed by the fluid closer to the silica wall than a suitable distance [delta] and the second by the fluid external to this shell. The sample scattering-length densities and shell thicknesses are determined by the Porod invariants and the oscillations observed in the Porod plots of the SANS intensities. The resulting matter densities of the shell regions (thickness 15-35 {angstrom}) are approximately equal, while those of the outer regions increase with pressure and become equal to the bulk CO2 at the higher pressures only in the low-temperature case.
Ciccariello, Salvino [Universita di Padova; Melnichenko, Yuri B [ORNL; He, Lilin [ORNL
Process for manufacturing hollow fused-silica insulator cylinder
A method for building hollow insulator cylinders that can have each end closed off with a high voltage electrode to contain a vacuum. A series of fused-silica round flat plates are fabricated with a large central hole and equal inside and outside diameters. The thickness of each is related to the electron orbit diameter of electrons that escape the material surface, loop, and return back. Electrons in such electron orbits can support avalanche mechanisms that result in surface flashover. For example, the thickness of each of the fused-silica round flat plates is about 0.5 millimeter. In general, the thinner the better. Metal, such as gold, is deposited onto each top and bottom surface of the fused-silica round flat plates using chemical vapor deposition (CVD). Eutectic metals can also be used with one alloy constituent on the top and the other on the bottom. The CVD, or a separate diffusion step, can be used to defuse the deposited metal deep into each fused-silica round flat plate. The conductive layer may also be applied by ion implantation or gas diffusion into the surface. The resulting structure may then be fused together into an insulator stack. The coated plates are aligned and then stacked, head-to-toe. Such stack is heated and pressed together enough to cause the metal interfaces to fuse, e.g., by welding, brazing or eutectic bonding. Such fusing is preferably complete enough to maintain a vacuum within the inner core of the assembled structure. A hollow cylinder structure results that can be used as a core liner in a dielectric wall accelerator and as a vacuum envelope for a vacuum tube device where the voltage gradients exceed 150 kV/cm.
Sampayan, Stephen E. (Manteca, CA); Krogh, Michael L. (Lee's Summit, MO); Davis, Steven C. (Lee's Summit, MO); Decker, Derek E. (Discovery Bay, CA); Rosenblum, Ben Z. (Overland Park, KS); Sanders, David M. (Livermore, CA); Elizondo-Decanini, Juan M. (Albuquerque, NM)
Silica aerogel: An intrinsically low dielectric constant material
Silica aerogels are highly porous solids having unique morphologies in wavelength of visible which both the pores and particles have sizes less than the wavelength of visible light. This fine nanostructure modifies the normal transport mechanisms within aerogels and endows them with a variety of exceptional physical properties. For example, aerogels have the lowest measured thermal conductivity and dielectric constant for any solid material. The intrinsically low dielectric properties of silica aerogels are the direct result of the extremely high achievable porosities, which are controllable over a range from 75% to more than 99.8 %, and which result in measured dielectric constants from 2.0 to less than 1.01. This paper discusses the synthesis of silica aerogels, processing them as thin films, and characterizing their dielectric properties. Existing data and other physical characteristics of bulk aerogels (e.g., thermal stablity, thermal expansion, moisture adsorption, modulus, dielectric strength, etc.), which are useful for evaluating them as potential dielectrics for microelectronics, are also given.
Hrubesh, L.W.
Measurement of Radiation Damage on Silica Aerogel Cerenkov Radiator
We measured the radiation damage on silica aerogel Cerenkov radiators originally developed for the B-factory experiment at KEK. Refractive index of the aerogel samples ranged from 1.012 to 1.028. The samples were irradiated up to 9.8 MRad of equivalent dose. Measurements of transmittance and refractive index were carried out and these samples were found to be radiation hard. Deteriorations in transparency and changes of refractive index were observed to be less than 1.3% and 0.001 at 90% confidence level, respectively. Prospects of using aerogels under high-radiation environment are discussed. 1 Introduction Silica aerogels(aerogels) are a colloidal form of glass, in which globules of silica are connected in three dimensional networks with siloxan bonds. They are solid, very light, transparent and their refractive index can be controlled in the production process. Many high energy and nuclear physics experiments have used aerogels instead of pressurized gas for their Cerenkov coun...
Belle Preprint; Sahu Wang; M. Z. Wang; R. Suda; R. Enomoto; K. C. Peng; C. H. Wang; I. Adachi; M. Amami
Multimodality Imaging with Silica-Based Targeted Nanoparticle Platforms
Objectives: To synthesize and characterize a C-Dot silica-based nanoparticle containing 'clickable' groups for the subsequent attachment of targeting moieties (e.g., peptides) and multiple contrast agents (e.g., radionuclides with high specific activity) [1,2]. These new constructs will be tested in suitable tumor models in vitro and in vivo to ensure maintenance of target-specificity and high specific activity. Methods: Cy5 dye molecules are cross-linked to a silica precursor which is reacted to form a dye-rich core particle. This core is then encapsulated in a layer of pure silica to create the core-shell C-Dot (Figure 1) [2]. A 'click' chemistry approach has been used to functionalize the silica shell with radionuclides conferring high contrast and specific activity (e.g. 64Cu and 89Zr) and peptides for tumor targeting (e.g. cRGD and octreotate) [3]. Based on the selective Diels-Alder reaction between tetrazine and norbornene, the reaction is bioorthogonal, highyielding, rapid, and water-compatible. This radiolabeling approach has already been employed successfully with both short peptides (e.g. octreotate) and antibodies (e.g. trastuzumab) as model systems for the ultimate labeling of the nanoparticles [1]. Results: PEGylated C-Dots with a Cy5 core and labeled with tetrazine have been synthesized (d = 55 nm, zeta potential = -3 mV) reliably and reproducibly and have been shown to be stable under physiological conditions for up to 1 month. Characterization of the nanoparticles revealed that the immobilized Cy5 dye within the C-Dots exhibited fluorescence intensities over twice that of the fluorophore alone. The nanoparticles were successfully radiolabeled with Cu-64. Efforts toward the conjugation of targeting peptides (e.g. cRGD) are underway. In vitro stability, specificity, and uptake studies as well as in vivo imaging and biodistribution investigations will be presented. Conclusions: C-Dot silica-based nanoparticles offer a robust, versatile, and multi-functional platform to enhance in vivo detection sensitivity and non-invasively assay receptor expression/status of tumor cellular targets, including those of low abundance, using nuclear-NIR fluorescence imaging approaches [2]. Improvements in molecular diagnostics, refined by the availability of nanotechnology platforms, will be a key determinant in driving early-stage disease detection and prevention, ultimately leading to decreases in mortality.
Jason S. Lewis
Sodium fast reactor safety and licensing research plan. Volume II.
Expert panels comprised of subject matter experts identified at the U.S. National Laboratories (SNL, ANL, INL, ORNL, LBL, and BNL), universities (University of Wisconsin and Ohio State University), international agencies (IRSN, CEA, JAEA, KAERI, and JRC-IE) and private consultation companies (Radiation Effects Consulting) were assembled to perform a gap analysis for sodium fast reactor licensing. Expert-opinion elicitation was performed to qualitatively assess the current state of sodium fast reactor technologies. Five independent gap analyses were performed resulting in the following topical reports: (1) Accident Initiators and Sequences (i.e., Initiators/Sequences Technology Gap Analysis), (2) Sodium Technology Phenomena (i.e., Advanced Burner Reactor Sodium Technology Gap Analysis), (3) Fuels and Materials (i.e., Sodium Fast Reactor Fuels and Materials: Research Needs), (4) Source Term Characterization (i.e., Advanced Sodium Fast Reactor Accident Source Terms: Research Needs), and (5) Computer Codes and Models (i.e., Sodium Fast Reactor Gaps Analysis of Computer Codes and Models for Accident Analysis and Reactor Safety). Volume II of the Sodium Research Plan consolidates the five gap analysis reports produced by each expert panel, wherein the importance of the identified phenomena and necessities of further experimental research and code development were addressed. The findings from these five reports comprised the basis for the analysis in Sodium Fast Reactor Research Plan Volume I.
Ludewig, H. (Brokhaven National Laboratory, Upton, NY); Powers, D. A.; Hewson, John C.; LaChance, Jeffrey L.; Wright, A. (Argonne National Laboratory, Argonne, IL); Phillips, J.; Zeyen, R. (Institute for Energy Petten, Saint-Paul-lez-Durance, France); Clement, B. (IRSN/DPAM.SEMIC Bt 702, Saint-Paul-lez-Durance, France); Garner, Frank (Radiation Effects Consulting, Richland, WA); Walters, Leon (Advanced Reactor Concepts, Los Alamos, NM); Wright, Steve; Ott, Larry J. (Oak Ridge National Laboratory, Oak Ridge, TN); Suo-Anttila, Ahti Jorma; Denning, Richard (Ohio State University, Columbus, OH); Ohshima, Hiroyuki (Japan Atomic Energy Agency, Ibaraki, Japan); Ohno, S. (Japan Atomic Energy Agency, Ibaraki, Japan); Miyhara, S. (Japan Atomic Energy Agency, Ibaraki, Japan); Yacout, Abdellatif (Argonne National Laboratory, Argonne, IL); Farmer, M. (Argonne National Laboratory, Argonne, IL); Wade, D. (Argonne National Laboratory, Argonne, IL); Grandy, C. (Argonne National Laboratory, Argonne, IL); Schmidt, R.; Cahalen, J. (Argonne National Laboratory, Argonne, IL); Olivier, Tara Jean; Budnitz, R. (Lawrence Berkeley National Laboratory, Berkeley, CA); Tobita, Yoshiharu (Japan Atomic Energy Agency, Ibaraki, Japan); Serre, Frederic (Centre d'%C3%94etudes nucl%C3%94eaires de Cadarache, Cea, France); Natesan, Ken (Argonne National Laboratory, Argonne, IL); Carbajo, Juan J. (Oak Ridge National Laboratory, Oak Ridge, TN); Jeong, Hae-Yong (Korea Atomic Energy Research Institute, Daejeon, Korea); Wigeland, Roald (Idaho National Laboratory, Idaho Falls, ID); Corradini, Michael (University of Wisconsin-Madison, Madison, WI); Thomas, Justin (Argonne National Laboratory, Argonne, IL); Wei, Tom (Argonne National Laboratory, Argonne, IL); Sofu, Tanju (Argonne National Laboratory, Argonne, IL); Flanagan, George F. (Oak Ridge National Laboratory, Oak Ridge, TN); Bari, R. (Brokhaven National Laboratory, Upton, NY); Porter D. (Idaho National Laboratory, Idaho Falls, ID); Lambert, J. (Argonne National Laboratory, Argonne, IL); Hayes, S. (Idaho National Laboratory, Idaho Falls, ID); Sackett, J. (Idaho National Laboratory, Idaho Falls, ID); Denman, Matthew R.
Sodium cobalt bronze batteries and a method for making same
A solid state secondary battery utilizing a low cost, environmentally sound, sodium cobalt bronze electrode. A method is provided for producing same.
Doeff, Marca M. (Hayward, CA); Ma, Yanping (Berkeley, CA); Visco, Steven J. (Berkeley, CA); DeJonghe, Lutgard (Lafayette, CA)
A solid state secondary battery utilizing a low cost, environmentally sound, sodium cobalt bronze electrode is described. A method is provided for producing same. 11 figs.
Doeff, M.M.; Ma, Y.; Visco, S.J.; DeJonghe, L.
Idaho Site Obtains Patent for Nuclear Reactor Sodium Cleanup...
Office of Environmental Management (EM)
Idaho Site Obtains Patent for Nuclear Reactor Sodium Cleanup Treatment March 28, 2013 - 12:00pm Addthis CWI engineers Jeff Jones, David Tolman, right, and Kirk Dooley...
Efficacy of soluble sodium tripolyphosphate amendments for the...
of soluble sodium tripolyphosphate amendments for the in-situ immobilisation of uranium."Environmental Chemistry 4:293-300. Authors: DM Wellman EM Pierce MM Valenta...
aqueous sodium sulfate: Topics by E-print Network
viscosity, 771, for PDMDAAC fractions in sodium chloride solutions by viscosity, size-exclusionchromatography, and light Dubin, Paul D. 32 Structure and Dynamics in Aqueous...
Preparation of silica stabilized biological templates for the production of metal and layered nanoparticles
The present invention relates to a system and method providing for increased silica growth on a bio-template, wherein the bio-template is pretreated with aniline to produce a uniform silica attractive surface and yielding a significant silica layers of at least 10 nm, and more preferably at least 20 nm in thickness, thereby providing for a high degree of stability to the bio-template.
Culver, James N; Royston, Elizabeth; Brown, Adam; Harris, Michael
Sodium dichromate expedited response action assessment
The US Environmental Protection Agency (EPA) and Washington Department of Ecology (Ecology) recommended that the US Department of Energy (DOE) perform an expedited response action (ERA) for the Sodium Dichromate Barrel Disposal Landfill. The ERA lead regulatory agency is Ecology and EPA is the support agency. The ERA was categorized as non-time-critical, which required preparation of an engineering evaluation and cost analysis (EE/CA). The EE/CA was included in the ERA proposal. The EE/CA is a rapid, focused evaluation of available technologies using specific screening factors to assess feasibility, appropriateness, and cost. The ERA goal is to reduce the potential for any contaminant migration from the landfill to the soil column, groundwater, and Columbia River. Since the Sodium Dichromate Barrel Disposal Landfill is the only waste site within the operable unit, the removal action may be the final remediation of the 100-IU-4 Operable Unit. This ERA process started in March 1992. The ERA proposal went through a parallel review process with Westinghouse Hanford Company (WHC), DOE Richland Operations (RL), EPA, Ecology, and a 30-day public comment period. Ecology and EPA issued an Action Agreement Memorandum in March 1993 (Appendix A). The memorandum directed excavation of all anomalies and disposal of the collected materials at the Hanford Site Central Landfill. Primary field activities were completed by the end of April 1993. Final waste disposal of a minor quantity of hazardous waste was completed in July 1993.
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Extensional rheology of shear-thickening fumed silica nanoparticles dispersed in an aqueous polyethylene
polyethylene oxide solution Sunilkumar Khandavalli and Jonathan P. Rothsteina) Mechanical and Industrial rheology of fumed silica nanoparticles dispersed in an aqueous polyethylene oxide (PEO) solution
Rothstein, Jonathan
Biotransformation of Two-Line Silica-Ferrihydrite by a Dissimilatory...
by a Dissimilatory Fe(III)-Reducing Bacterium: Formation of Carbonate Green Biotransformation of Two-Line Silica-Ferrihydrite by a Dissimilatory Fe(III)-Reducing...
Sol-Gel Mesoporous Silica Aerogels and Bio Hybrids for Functional Applications.
??The thesis covers a systematic investigation on the synthesis of silica aerogels and microspheres with tailored porosity, at ambient conditions by varying the experimental parameters� (more)
Smitha, Sasidharan
E-Print Network 3.0 - acid-modified silica nanoparticles Sample...
as 3D Scaffolds for New Materials: from Mechanically Strong Polymer Crosslinked Aerogels Summary: of X-aerogels where skeletal inorganic nanoparticles (e.g., silica and >30...
E-Print Network 3.0 - amorphous silica exposed Sample Search...
> >> Page: << < 1 2 3 4 5 > >> 81 Terahertz Time-Domain Spectroscopy Study of Silica Aerogels and Adsorbed Molecular Jiangquan Zhang and D. Grischkowsky* Summary: fundamental...
TESLA-FEL 2004-01 Silica Aerogel Radiators for Bunch Length Measurements ?
Cherenkov radiators based on Silica aerogel are used to measure the electron bunch length at the photo injector test facility at DESY Zeuthen (PITZ). The energy range of those electrons is 4-5 MeV. In this paper the time resolution defined by the usage of aerogel is calculated analytically and Monte Carlo simulations are performed. It is shown that Silica aerogel gives the possibility to reach a time resolution of about 0.1 ps for high photon intensities and a time resolution of about 0.02 ps can be obtained for thin Silica aerogel radiators. Key words: silica aerogel, bunch length, time resolution, PITZ 1
J. B�hr A; V. Djordjadze A; D. Lipka A; A. Onuchin B; F. Stephan A
E-Print Network 3.0 - acid functionalized silica Sample Search...
Materials Science ; Engineering 18 The influence of void space on antireflection coatings of silica nanoparticle self-assembled films Summary: nanoparticles on a silver...
E-Print Network 3.0 - amine catalyzed silica Sample Search Results
the elastic modulus with epoxy loading, for an epoxy- crosslinked, amine-modified silica aerogel. Those... authors argued that the epoxy bridges the neighboring amine- modified...
E-Print Network 3.0 - acid modified silica Sample Search Results
Accelerated test methods for evaluating alkali-silica reactivity of recycled concrete aggregates.
??This thesis reports the findings of a study carried out to determine the effectiveness of Accelerated Tests in evaluating the Alkali-Silica Reactivity of Recycled Concrete� (more)
Johnson, Robert C (Author)
Synthesis of Mesocellular Silica Foams with Tunable Window and Cell Dimensions
Polystyrene microspheres coated with cationic surfactants are easily prepared by micro- emulsion templates. These silica foams resemble dense aerogels. Introduction Because of their greatly enhanced pore
Yang, Peidong
E-Print Network 3.0 - ash slag silica Sample Search Results
Engineering ; Materials Science 91 By-Products Utilization Summary: pozzolans include coal fly ash, blast furnace slag, silica fume, and other combustion ashes. When...
Construction of a multi-functional cryogenic propellant tank with cross-linked silica aerogel.
??Aerogels are low-density nanostructured porous materials, whose practical applications have been limited by their poor mechanical properties. Crosslinking the nanoparticle building blocks of silica aerogels� (more)
Reinheimer, Preston Glenn
Polymer reinforced aerogels and composites A. Polyimide crosslinked aerogels B. Silica-polymethylmethacrylate composites .
??"Crosslinking of aerogels is a promising approach to combine the advantages of inorganic and polymeric materials. In the present study, two types of polyimide-silica hybrid� (more)
Patil, Vishal U., 1981-
RESEARCH Open Access Half-molar sodium lactate infusion improves
RESEARCH Open Access Half-molar sodium lactate infusion improves cardiac performance in acute heart for the myocardium at rest and during stress. We tested the effects of half-molar sodium lactate infusion on cardiac by 1 ml/kg/h continuous infusion for 24 hours. The control group received only a 3 ml/kg bolus
Mercury exosphere I. Global circulation model of its sodium component
Mercury exosphere I. Global circulation model of its sodium component Francois Leblanc a,*, R 2010 Accepted 27 April 2010 Available online 5 May 2010 Keywords: Mercury, Atmosphere Aeronomy a b s t r a c t Our understanding of Mercury's sodium exosphere has improved considerably in the last 5
Johnson, Robert E.
Thermal annealing of laser damage precursors on fused silica surfaces
Previous studies have identified two significant precursors of laser damage on fused silica surfaces at fluenes below {approx} 35 J/cm{sup 2}, photoactive impurities in the polishing layer and surface fractures. In the present work, isothermal heating is studied as a means of remediating the highly absorptive, defect structure associated with surface fractures. A series of Vickers indentations were applied to silica surfaces at loads between 0.5N and 10N creating fracture networks between {approx} 10{micro}m and {approx} 50{micro}m in diameter. The indentations were characterized prior to and following thermal annealing under various times and temperature conditions using confocal time-resolved photo-luminescence (CTP) imaging, and R/1 optical damage testing with 3ns, 355nm laser pulses. Significant improvements in the damage thresholds, together with corresponding reductions in CTP intensity, were observed at temperatures well below the glass transition temperature (T{sub g}). For example, the damage threshold on 05.N indentations which typically initiates at fluences <8 J/cm{sup 2} could be improved >35 J/cm{sup 2} through the use of a {approx} 750 C thermal treatment. Larger fracture networks required longer or higher temperature treatment to achieve similar results. At an annealing temperature > 1100 C, optical microscopy indicates morphological changes in some of the fracture structure of indentations, although remnants of the original fracture and significant deformation was still observed after thermal annealing. This study demonstrates the potential of using isothermal annealing as a means of improving the laser damage resistance of fused silica optical components. Similarly, it provides a means of further understanding the physics associated with optical damage and related mitigation processes.
Shen, N; Miller, P E; Bude, J D; Laurence, T A; Suratwala, T I; Steele, W A; Feit, M D; Wang, L L
Association of length-slow silica with evaporites
In 1971, Folk and Pittman described the common occurrence of length-slow quartz (or lutecite) with evaporitic minerals, and they suggested that lutecite might be a useful indicator for vanished evaporites. However, the subsequent discoveries of length-slow silica in carbonate turbidites and in abyssal Pacific cherts revealed that lutecite is not restricted to near-surface deposits. Moreover, Kastner found that length-slow quartz could be crystallized in slightly alkaline solutions enriched in Mg[sup 2+], Na[sup +], and SO[sub 4][sup [minus]2]. Following these studies, researchers have cited the presence of lutecite in rock samples as suggestive but not compelling evidence for an evaporitic origin, and the precise nature of this form of silica has remained somewhat enigmatic. Investigations of chert nodules from evaporitic and non-evaporitic regimes support an identification of length-slow quartz'' with the mineral moganite, a polymorph of silica that is fibrous and optically length slow. Results are based upon X-ray powder diffraction of the chert, followed by Rietveld refinement of the X-ray patterns to quantify the weight fraction of quartz and moganite in each specimen. Most non-evaporitic chert appears to contain between 5 and 15 wt. % moganite, but evaporitic cherts often contain more than 20 wt. %. Cherts that have transformed from precursor magadiite can be particularly rich in moganite; samples from Lake Magadi, Kenya and from Harney Lake, Oregon revealed about equal parts moganite and quartz. However, the observation of decreasing abundances of moganite in rocks of increasing age indicates that moganite is metastable relative to quartz.
Heaney, P.J. (Princeton Univ., Princeton, NJ (United States). Dept. of Geology); Sheppard, R.A. (Geological Survey, Denver, CO (United States). Denver Federal Center); Post, J.E. (Smithsonian Inst., Washington, DC (United States). Dept. of Mineral Sciences)
Low temperature sodium-beta battery
A battery that will operate at ambient temperature or lower includes an enclosure, a current collector within the enclosure, an anode that will operate at ambient temperature or lower within the enclosure, a cathode that will operate at ambient temperature or lower within the enclosure, and a separator and electrolyte within the enclosure between the anode and the cathode. The anode is a sodium eutectic anode that will operate at ambient temperature or lower and is made of a material that is in a liquid state at ambient temperature or lower. The cathode is a low melting ion liquid cathode that will operate at ambient temperature or lower and is made of a material that is in a liquid state at ambient temperature or lower.
Farmer, Joseph C
Chemical treatment for silica-containing glass surfaces
Dehydroxylated, silica-containing, glass surfaces are known to be at least partially terminated by strained siloxane rings. According to the invention, a surface of this kind is exposed to a selected silane compound or mixture of silane compounds under reaction-promoting conditions. The ensuing reaction results in opening of the strained siloxane rings, and termination of surface atoms by chemical species, such as organic or organosilicon species, having desirable properties. These species can be chosen to provide qualities such as hydrophobicity, or improved coupling to a polymeric coating. 11 figs.
Grabbe, A.; Michalske, T.A.; Smith, W.L.
Dehydroxylated, silica-containing, glass surfaces are known to be at least partially terminated by strained siloxane rings. According to the invention, a surface of this kind is exposed to a selected silane compound or mixture of silane compounds under reaction-promoting conditions. The ensuing reaction results in opening of the strained siloxane rings, and termination of surface atoms by chemical species, such as organic or organosilicon species, having desirable properties. These species can be chosen to provide qualities such as hydrophobicity, or improved coupling to a polymeric coating.
Grabbe, Alexis (Albuquerque, NM); Michalske, Terry Arthur (Bernalillo, NM); Smith, William Larry (Albuquerque, NM)
Method for chemical surface modification of fumed silica particles
Dehydroxylated, silica-containing, glass surfaces are known to be at least partially terminated by strained siloxane rings. According to the invention, a surface of this kind is exposed to a selected silane compound or mixture of silane compounds under reaction-promoting conditons. The ensuing reaction results in opening of the strained siloxane rings, and termination of surface atoms by chemical species, such as organic or organosilicon species, having desirable properties. These species can be chosen to provide qualities such as hydrophobicity, or improved coupling to a polymeric coating.
Grabbe, Alexis (Albuquerque, NM); Michalske, Terry Arthur (Cedar Crest, NM); Smith, William Larry (Albuquerque, NM)
Optical and radiographical characterization of silica aerogel for Cherenkov radiator
We present optical and X-ray radiographical characterization of silica aerogels with refractive index from 1.05 to 1.07 for a Cherenkov radiator. A novel pin-drying method enables us to produce highly transparent hydrophobic aerogels with high refractive index by shrinking wet-gels. In order to investigate the uniformity in the density (i.e., refractive index) of an individual aerogel monolith, we use the laser Fraunhofer method, an X-ray absorption technique, and Cherenkov imaging by a ring imaging Cherenkov detector in a beam test. We observed an increase in density at the edge of the aerogel tiles, produced by pin-drying.
Tabata, Makoto; Hatakeyama, Yoshikiyo; Kawai, Hideyuki; Morita, Takeshi; Nishikawa, Keiko
Makoto Tabata; Ichiro Adachi; Yoshikiyo Hatakeyama; Hideyuki Kawai; Takeshi Morita; Keiko Nishikawa
Measurement of Radiation Damage on Silica Aerogel \\v Cerenkov Radiator
We measured the radiation damage on silica aerogel \\v Cerenkov radiators originally developed for the $B$-factory experiment at KEK. Refractive index of the aerogel samples ranged from 1.012 to 1.028. The samples were irradiated up to 9.8~MRad of equivalent dose. Measurements of transmittance and refractive index were carried out and these samples were found to be radiation hard. Deteriorations in transparency and changes of refractive index were observed to be less than 1.3\\% and 0.001 at 90\\% confidence level, respectively. Prospects of using aerogels under high-radiation environment are discussed.
S. K. Sahu et al
The production of activated silica with carbon dioxide gas
Ional to the per cent of carbon dioxi. de 1n the flue gas for a constant total gas flow rate. REFE REN CES l. Andrews, R. V, , Hanford Works Eocument (1952), 2. Andrews, R. V. & J. A. W. W. A, , ~46 82 (1954). 3. Andrews, R. V, , Personal Communication 4... of the reciuire . ents for the dedree of iliASTER OF SCIENCE Janus', 1956 Major Subject: Chemi. cal Engineering TH PRODUCTION OP ACTIVATED SILICA 7iIITH CARBON DIOXIDE GAS A Thesis William Bell Hayes III Approved as to style and content by: Chairmen...
Hayes, William Bell
Silica Supported Ceria Nanoparticles: A Hybrid Nanostructure To Increase
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administrationcontroller systemsBi (2)Sharing Smart GridShift EndSidneyChemistry » Silica
Production of sodium-22 from proton irradiated aluminum
A process for selective separation of sodium-22 from a proton irradiated minum target including dissolving a proton irradiated aluminum target in hydrochloric acid to form a first solution including aluminum ions and sodium ions, separating a portion of the aluminum ions from the first solution by crystallization of an aluminum salt, contacting the remaining first solution with an anion exchange resin whereby ions selected from the group consisting of iron and copper are selectively absorbed by the anion exchange resin while aluminum ions and sodium ions remain in solution, contacting the solution with an cation exchange resin whereby aluminum ions and sodium ions are adsorbed by the cation exchange resin, and, contacting the cation exchange resin with an acid solution capable of selectively separating the adsorbed sodium ions from the cation exchange resin while aluminum ions remain adsorbed on the cation exchange resin is disclosed.
Taylor, Wayne A. (Los Alamos, NM); Heaton, Richard C. (Los Alamos, NM); Jamriska, David J. (Los Alamos, NM)
Theoretical Adiabatic Temperature and Chemical Composition of Sodium Combustion Flame
Sodium fire safety analysis requires fundamental combustion properties, e.g., heat of combustion, flame temperature, and composition. We developed the GENESYS code for a theoretical investigation of sodium combustion flame.Our principle conclusions on sodium combustion under atmospheric air conditions are (a) the maximum theoretical flame temperature is 1950 K, and it is not affected by the presence of moisture; the uppermost limiting factor is the chemical instability of the condensed sodium-oxide products under high temperature; (b) the main combustion product is liquid Na{sub 2}O in dry air condition and liquid Na{sub 2}O with gaseous NaOH in moist air; and (c) the chemical equilibrium prediction of the residual gaseous reactants in the flame is indispensable for sodium combustion modeling.
Okano, Yasushi; Yamaguchi, Akira [O-arai Engineering Center (Japan)
Calcium and sodium bentonite for hydraulic containment applications
The hydraulic conductivity of calcium and sodium bentonites was investigated for sand-bentonite mixtures, a thin bentonite layer simulating a geosynthetic clay liner (GCL), and bentonite-cement mixtures simulating backfill for a vertical cutoff wall. The permeant liquids were tap water and distilled water containing 0.25 M calcium chloride. In general, the hydraulic performance of calcium bentonite was not significantly better than the performance of sodium bentonite for either the clay-amended sand or the GCL application, and was substantially worse than the performance of sodium bentonite in the bentonite-cement mixture. A drained angle of internal friction of 21{degree} was measured for calcium bentonite, compared to 10{degree} for sodium bentonite. Except for a larger drained shear strength, no advantage of calcium bentonite over sodium bentonite could be identified from the results of this study.
Gleason, M.H. [GeoSyntec Consultants, Columbia, MD (United States); Daniel, D.E. [Univ. of Illinois, Urbana, IL (United States). Dept. of Civil Engineering; Eykholt, G.R. [Univ. of Wisconsin, Madison, WI (United States). Dept. of Civil Engineering
Decommissioning of Experimental Breeder Reactor - II Complex, Post Sodium Draining
The Experimental Breeder Reactor - II (EBR-II) was shutdown in September 1994 as mandated by the United States Department of Energy. This sodium-cooled reactor had been in service since 1964. The bulk sodium was drained from the primary and secondary systems and processed. Residual sodium remaining in the systems after draining was converted into sodium bicarbonate using humid carbon dioxide. This technique was tested at Argonne National Laboratory in Illinois under controlled conditions, then demonstrated on a larger scale by treating residual sodium within the EBR-II secondary cooling system, followed by the primary tank. This process, terminated in 2002, was used to place a layer of sodium bicarbonate over all exposed surfaces of sodium. Treatment of the remaining EBR-II sodium is governed by the Resource Conservation and Recovery Act (RCRA). The Idaho Department of Environmental Quality issued a RCRA Operating Permit in 2002, mandating that all hazardous materials be removed from EBR-II within a 10 year period, with the ability to extend the permit and treatment period for another 10 years. A preliminary plan has been formulated to remove the remaining sodium and NaK from the primary and secondary systems using moist carbon dioxide, steam and nitrogen, and a water flush. The moist carbon dioxide treatment was resumed in May 2004. As of August 2005, approximately 60% of the residual sodium within the EBR-II primary tank had been treated. This process will continue through the end of 2005, when it is forecast that the process will become increasingly ineffective. At that time, subsequent treatment processes will be planned and initiated. It should be noted that the processes and anticipated costs associated with these processes are preliminary. Detailed engineering has not been performed, and approval for these methods has not been obtained from the regulator or the sponsors.
J. A. (Bart) Michelbacher; S. Paul Henslee; Collin J. Knight; Steven R. sherman
Preparation of silica aerogels with improved mechanical properties and extremely low thermal conductivities through modified sol-gel process
Reported silica aerogels have a thermal conductivity as low as 15 mW/mK. The fragility of silica aerogels, however, makes them impractical for structural applications. The purpose of the study is to improve the ductility ...
Zuo, Yanjia
Preparation of silica aerogels with improved mechanical properties and extremely low thermal conductivities through modified sol-gel process .
??Reported silica aerogels have a thermal conductivity as low as 15 mW/mK. The fragility of silica aerogels, however, makes them impractical for structural applications. The� (more)
Ethylenediamine at Air/Liquid and Air/Silica Interfaces: Protonation
surface and EDA protonated products at air/liquid interfaces. The SFG spectra of EDA adsorbedEthylenediamine at Air/Liquid and Air/Silica Interfaces: Protonation Versus Hydrogen BondingKa (HOSit)) is between the two pKa values of EDA (in the range of 7.56-10.71) at the air/silica interface
DOI: 10.1002/adma.200701303 Nanolayered Carbon/Silica Superstructures via Organosilane
. A main advantage using mesoporous silica is to synthesize carbon/silica composite materials with tunable of amorphous carbon materials after carbonization, and uncontrolled morphologies of composite materials is typically high. However, the composites are not uniform; car- bonization mainly produces amorphous carbon
Zhu, Yuntian T.
Density hysteresis of heavy water confined in a nanoporous silica matrix
Density hysteresis of heavy water confined in a nanoporous silica matrix Yang Zhanga,b , Antonio of heavy water confined in a nanoporous silica matrix in a temperature-pressure range, from 300 to 130 K in the relevant phase region. More- over, the density data we obtained for the confined heavy water under
Chen, Sow-Hsin
Friction and Heat Transfer Characteristics of Silica and CNT Nanofluids in a Tube Flow
Friction and Heat Transfer Characteristics of Silica and CNT Nanofluids in a Tube Flow MILIVOJE email@example.com * www.kostic.niu.edu Abstract: - An apparatus for exploring friction and heat transfer characteristics flow. Initial turbulent friction and heat transfer measurements for silica and carbon nanotube (CNT
Kostic, Milivoje M.
The size and polydispersity of silica nanoparticles under simulated hot spring conditions
-through geothermal simu- lator system where polymerization was induced by rapid cooling. Changes in [SiO2], IS of silica nanoparticles in supersaturated geothermal waters was simulated using a flow-through geothermal of silica in active geothermal systems is a well-known process leading to the silicification
Benning, Liane G.
Mechanism of Elongation of Gold or Silver Nanoparticles in Silica by Irradiation with Swift Heavy Ions
1 Mechanism of Elongation of Gold or Silver Nanoparticles in Silica by Irradiation with Swift Heavy nanoparticles oriented parallel to one another can be synthesized in SiO2 by ion irradiation. Our aim, silica glass 1. Introduction Well-defined Au nanoparticles and nanorods are desirable for their optical
Boyer, Edmond
The onset of optical breakdown in KrF-laser-irradiated silica glass surfaces
A synthetic fused silica obtained from Tosoh SGM Co., ESL-1000 (OH % 1200 wt. ppm), with a thick- ness of 2 mmThe onset of optical breakdown in KrF-laser-irradiated silica glass surfaces Y. Kawaguchia,* , A Research Center, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 5, 1
Dickinson, J. Thomas
Surface Analysis of Silica Gel Particles after Mechanical Dry Coating with Magnesium Stearate
1 Surface Analysis of Silica Gel Particles after Mechanical Dry Coating with Magnesium Stearate particles (d50 = 55 µm) by coating with different mass ratios of magnesium stearate - MgSt2 (d50 = 4.6 µm Group). Keywords: AFM phase imaging, adhesion force, dry coating, silica, magnesium stearate. 1
Pulsed infrared laser annealing of gold nanoparticles embedded in a silica A. Halabica,1,a
Pulsed infrared laser annealing of gold nanoparticles embedded in a silica matrix A. Halabica,1,a J; published online 28 April 2008 Pulsed infrared laser irradiation was used to modify the optical and physical in a fused-silica matrix. The experiments demonstrate the unique effects of fast thermal heating
Pennycook, Steve
ORIGINAL PAPER Algal-silica cycling and pigment diagenesis in recent alpine
dis- solved within 50 years of deposition. Diatom dissolu- tion, silica recycling, and diageneticO2, hereafter BSi) in lake sediments that has led to their common use in freshwater paleoecology have the lowest preservation potential for diatom frustules. However, the recycling of diatom silica
Konhauser, Kurt
Stress dependent activation entropy for dynamic fatigue of pristine silica optical fibers
Subcritical crack growth in fused silica is treated as a stress assisted chemical reaction between water distilled water and pH 7 buffer solution, and the results are found to be similar. The fatigue parameters to the barrier height. The results show subcritical crack growth in high strength silica is dominated by entropy
Matthewson, M. John
Hybrid structure laser based on semiconductor nanowires and a silica microfiber knot cavity
Hybrid structure laser based on semiconductor nanowires and a silica microfiber knot cavity Qing://apl.aip.org/about/rights_and_permissions #12;Hybrid structure laser based on semiconductor nanowires and a silica microfiber knot cavity Qing 2009 We demonstrate a hybrid structure laser consisting of a single or multiple zinc oxide Zn
Wu, Shin-Tson
Hybrid Silica-PVA Nanofibers via Sol-Gel Electrospinning Tahira Pirzada,,
Hybrid Silica-PVA Nanofibers via Sol-Gel Electrospinning Tahira Pirzada,,§ Sara A. Arvidson,,§ Carl: We report on the synthesis of poly(vinyl alcohol) (PVA)-silica hybrid nanofibers via sol-gel electro is under- taken and reveals a composition window in which defect-free hybrid nanofibers with diameters
Khan, Saad A.
Integrated Optical Orbital Angular Momentum Multiplexing Device using 3-D Waveguides and a Silica PLC
PLC Binbin Guan,1 Ryan P. Scott,1 Nicolas K. Fontaine,2 Tiehui Su,1 Carlo Ferrari,3 Mark Cappuzzo,3 on a silica planar lightwave circuit (PLC) coupled to a 3-D photonic circuit that efficiently generates planar lightwave circuit (PLC) with a silica 3-D PIC that supports up to 15 OAM modes, both TE and TM
Yoo, S. J. Ben
Preparation of Micrometer-to Sub-micrometer-Sized Nanostructured Silica Particles Using High-Energy Ball Milling
, mesoporous silica synthesized in the form of thin films,3 aerogels,4 and particles are the most cited
Mitchell, Brian S.
Characterization of zirconia- and niobia-silica mixture coatings produced by ion-beam sputtering
ZrO{sub 2}-SiO{sub 2} and Nb{sub 2}O{sub 5}-SiO{sub 2} mixture coatings as well as those of pure zirconia (ZrO{sub 2}), niobia (Nb{sub 2}O{sub 5}), and silica (SiO{sub 2}) deposited by ion-beam sputtering were investigated. Refractive-index dispersions, bandgaps, and volumetric fractions of materials in mixed coatings were analyzed from spectrophotometric data. Optical scattering, surface roughness, nanostructure, and optical resistance were also studied. Zirconia-silica mixtures experience the transition from crystalline to amorphous phase by increasing the content of SiO{sub 2}. This also results in reduced surface roughness. All niobia and silica coatings and their mixtures were amorphous. The obtained laser-induced damage thresholds in the subpicosecond range also correlates with respect to the silica content in both zirconia- and niobia-silica mixtures.
Melninkaitis, Andrius; Tolenis, Tomas; Mazule, Lina; Mirauskas, Julius; Sirutkaitis, Valdas; Mangote, Benoit; Fu Xinghai; Zerrad, Myriam; Gallais, Laurent; Commandre, Mireille; Kicas, Simonas; Drazdys, Ramutis
Dielectric and magnetic properties of some gadolinium silica nanoceramics
Some nanostructure gadolinium silica glass-ceramics were obtained undergoing a sol gel method and a heat-treatment at 1000�C about two hours. The magnetic and dielectric properties of these samples were studied. The magnetic properties were evidenced performing susceptibility measurements in the 80-300K temperature range. A Curie-Weiss behavior has acquired. The values estimated for paramagnetic Curie temperature being small and positive suggest the presence of weak ferromagnetic interactions between Gd{sup 3+} ions. The dielectric properties were evaluated from dielectric permittivity (?{sub r}) and dielectric loss (tan?) measurements at the frequency 1 kHz, 10 kHz and 100 kHz, in the 25-225�C temperature range and dielectric dispersion at room temperature for 79.5 kHz - 1GHz frequency area. The dielectric properties suggest that the main polarization mechanism corresponds to interfacial polarization, characteristic for polycrystalline-structured dielectrics. The polycrystalline structure of the samples is due to the polymorphous transformations of the nanostructure silica crystallites in the presence of gadolinium oxide. They were highlighted by SEM micrographs.
Coroiu, I., E-mail: email@example.com; Pascuta, P., E-mail: email@example.com; Bosca, M., E-mail: email@example.com; Culea, E., E-mail: firstname.lastname@example.com [Technical University, Chemical and Physics Department, 28, Memorandumului, 400114, Cluj-Napoca (Romania)
The LHCb RICH silica aerogel performance with LHC data
In the LHCb detector at the Large Hadron Collider, powerful charged particle identification is performed by Ring Imaging Cherenkov (RICH) technology. In order to cover the full geometric acceptance and the wide momentum range (1-100 GeV/c), two detectors with three Cherenkov radiators have been designed and installed. In the medium (10-40 GeV/c) and high (30-100 GeV/c) momentum range, gas radiators are used (C4F10 and CF4 respectively). In the low momentum range (1 to a few GeV/c) pion/kaon/proton separation will be done with photons produced in solid silica aerogel. A set of 16 tiles, with the large transverse dimensions ever (20x20 cm$^2$) and nominal refractive index 1.03 have been produced. The tiles have excellent optical properties and homogeneity of refractive index within the tile of ~1%. The first data collected at LHC are used to understand the behaviour of the RICH: preliminary results will be presented and discussed on the performance of silica aerogel and of the gas radiators C4F10 and CF4.
Perego, D L
Chitosan, a polymer that is soluble in dilute aqueous acid, is derived from chitin, a natural polyglucosamide. Aquagels where the solid phase consists of both chitosan and silica can be easily prepared by using an acidic solution of chitosan to catalyze the hydrolysis and condensation of tetraethylorthosilicate. Gels with chitosan/TEOS mass ratios of 0.1-1.1 have been prepared by this method. Standard drying processes using CO{sub 2} give the corresponding aerogels. The amount of chitosan in the gel plays a role in the shrinkage of the aerogel during drying. Gels with the lowest chitosan/silica ratios show the most linear shrinkage, up to 24%, while those with the highest ratios show only a 7% linear shrinkage. Pyrolysis at 700 C under nitrogen produces a darkened aerogel due to the thermal decomposition of the chitosan, however, the aerogel retains its monolithic form. The pyrolyzed aerogels absorb slightly more infrared radiation in the 2-5 {micro}m region than the original aerogels. B.E.T. surface areas of these aerogels range from 470-750 m{sup 2}/g. Biocompatibility screening of this material shows a very high value for hemolysis, but a low value for cytotoxicity.
Macroscopic Subdivision of Silica Aerogel Collectors for Sample Return Missions
Silica aerogel collector tiles have been employed for the collection of particles in low Earth orbit and, more recently, for the capture of cometary particles by NASA's Stardust mission. Reliable, reproducible methods for cutting these and future collector tiles from sample return missions are necessary to maximize the science output from the extremely valuable embedded particles. We present a means of macroscopic subdivision of collector tiles by generating large-scale cuts over several centimeters in silica aerogel with almost no material loss. The cut surfaces are smooth and optically clear allowing visual location of particles for analysis and extraction. This capability is complementary to the smaller-scale cutting capabilities previously described [Westphal (2004), Ishii (2005a, 2005b)] for removing individual impacts and particulate debris in tiny aerogel extractions. Macroscopic cuts enable division and storage or distribution of portions of aerogel tiles for immediate analysis of samples by certain techniques in situ or further extraction of samples suited for other methods of analysis.
Ishii, H A; Bradley, J P
E-Print Network 3.0 - acetate sodium lactate Sample Search Results
sodium-high lactate infusion'. Of course, it is easy to demonstrate that high lactate infusion... . Also, sodium-lactate infusion in humans ... Source: Ecole Polytechnique, Centre...
E-Print Network 3.0 - advanced fast sodium Sample Search Results
sodium in the PFBR). The same initiating events occurring in both thermal and fast reactors could produce... specifications of demonstration fast reactors.* Thermal Sodium void...
Fluorescent single walled nanotube/silica composite materials
Fluorescent composites of surfactant-wrapped single-walled carbon nanotubes (SWNTs) were prepared by exposing suspensions of surfactant-wrapped carbon nanotubes to tetramethylorthosilicate (TMOS) vapor. Sodium deoxycholate (DOC) and sodium dodecylsulphate (SDS) were the surfactants. No loss in emission intensity was observed when the suspension of DOC-wrapped SWNTs were exposed to the TMOS vapors, but about a 50% decrease in the emission signal was observed from the SDS-wrapped SWNTs nanotubes. The decrease in emission was minimal by buffering the SDS/SWNT suspension prior to forming the composite. Fluorescent xerogels were prepared by adding glycerol to the SWNT suspensions prior to TMOS vapor exposure, followed by drying the gels. Fluorescent aerogels were prepared by replacing water in the gels with methanol and then exposing them to supercritical fluid drying conditions. The aerogels can be used for gas sensing.
Dattelbaum, Andrew M.; Gupta, Gautam; Duque, Juan G.; Doorn, Stephen K.; Hamilton, Christopher E.; DeFriend Obrey, Kimberly A.
Terahertz Time-Domain Spectroscopy Study of Silica Aerogels and Adsorbed Molecular Jiangquan Zhang and D. Grischkowsky*
Terahertz Time-Domain Spectroscopy Study of Silica Aerogels and Adsorbed Molecular Vapors Jiangquan time-domain spectroscopy (THz-TDS) study of hydrophobic and hydrophilic silica aerogels, and the adsorption of several molecular vapors in the hydrophilic silica aerogel. The hydrophobic and hydrophilic
THE JOURNAL OF CHEMICAL PHYSICS 140, 224502 (2014) Search for a liquid-liquid critical point in models of silica
from pure sil- ica are widely used by the telecommunications industry and, because silica and silicates in models of silica Erik Lascaris,1 Mahin Hemmati,2 Sergey V. Buldyrev,3 H. Eugene Stanley,1 and C. Austen indicated the possible existence of a liquid-liquid critical point (LLCP) in models of silica at high
Stanley, H. Eugene
Research papers Polymerization of aqueous silica in H2OK2O solutions at 25200 C and 1 bar
Research papers Polymerization of aqueous silica in H2OK2O solutions at 25200 °C and 1 bar to 20 Aqueous silica polymerization Diamond anvil cell Alkaline uids Ab initio calculation Understanding the polymerization of aqueous silica is important for modeling uidrock interactions at high pressure and temperature
Aluminum and silica intake in drinking water and the risk of Alzheimer's disease or cognitive decline: findings of the
Aluminum and silica intake in drinking water and the risk of Alzheimer's disease or cognitive,2 , Commenges Daniel1,2 , Helmer Catherine2,3 , Jean-François Dartigues2,3 . Abbreviations: Al, Aluminum; AD, Alzheimer's Disease; MMSE, Mini Mental State Examination; Si, Silica Running head: Aluminum, silica in water
Experimental investigations on sodium plugging in narrow flow channels.
A series of experiments was performed to investigate the potential for plugging of narrow flow channels of sodium by impurities (e.g., oxides). In the first phase of the experiments, clean sodium was circulated through the test sections simulating flow channels in a compact diffusion-bonded heat exchanger such as a printed circuit heat exchanger. The primary objective was to see if small channels whose cross sections are semicircles of 2, 4, and 6 mm in diameter are usable in liquid sodium applications where sodium purity is carefully controlled. It was concluded that the 2-mm channels, the smallest of the three, could be used in clean sodium systems at temperatures even as low as 100 to 110 C without plugging. In the second phase, sodium oxide was added to the loop, and the oxygen concentration in the liquid sodium was controlled by means of varying the cold-trap temperature. Intentional plugging was induced by creating a cold spot in the test sections, and the subsequent plugging behavior was observed. It was found that plugging in the 2-mm test section was initiated by lowering the cold spot temperature below the cold-trap temperature by 10 to 30 C. Unplugging of the plugged channels was accomplished by heating the affected test section.
Momozaki, Y.; Cho, D. H.; Sienicki, J. J.; Moisseytsev, A.; Nuclear Engineering Division
Apoptosis induction by silica nanoparticles mediated through reactive oxygen species in human liver cell line HepG2
Silica nanoparticles are increasingly utilized in various applications including agriculture and medicine. In vivo studies have shown that liver is one of the primary target organ of silica nanoparticles. However, possible mechanisms of hepatotoxicity caused by silica nanoparticles still remain unclear. In this study, we explored the reactive oxygen species (ROS) mediated apoptosis induced by well-characterized 14 nm silica nanoparticles in human liver cell line HepG2. Silica nanoparticles (25�200 ?g/ml) induced a dose-dependent cytotoxicity in HepG2 cells. Silica nanoparticles were also found to induce oxidative stress in dose-dependent manner indicated by induction of ROS and lipid peroxidation and depletion of glutathione (GSH). Quantitative real-time PCR and immunoblotting results showed that both the mRNA and protein expressions of cell cycle checkpoint gene p53 and apoptotic genes (bax and caspase-3) were up-regulated while the anti-apoptotic gene bcl-2 was down-regulated in silica nanoparticles treated cells. Moreover, co-treatment of ROS scavenger vitamin C significantly attenuated the modulation of apoptotic markers along with the preservation of cell viability caused by silica nanoparticles. Our data demonstrated that silica nanoparticles induced apoptosis in human liver cells, which is ROS mediated and regulated through p53, bax/bcl-2 and caspase pathways. This study suggests that toxicity mechanisms of silica nanoparticles should be further investigated at in vivo level. -- Highlights: ? We explored the mechanisms of toxicity caused by silica NPs in human liver HepG2 cells. ? Silica NPs induced a dose-dependent cytotoxicity in HepG2 cells. ? Silica NPs induced ROS generation and oxidative stress in a dose-dependent manner. ? Silica NPs were also modulated apoptosis markers both at mRNA and protein levels. ? ROS mediated apoptosis induced by silica NPs was preserved by vitamin C.
Ahmad, Javed [Department of Zoology, College of Science, King Saud University, Riyadh 11451 (Saudi Arabia)] [Department of Zoology, College of Science, King Saud University, Riyadh 11451 (Saudi Arabia); Ahamed, Maqusood, E-mail: firstname.lastname@example.com [King Abdullah Institute for Nanotechnology, King Saud University, Riyadh 11451 (Saudi Arabia)] [King Abdullah Institute for Nanotechnology, King Saud University, Riyadh 11451 (Saudi Arabia); Akhtar, Mohd Javed [Fibre Toxicology, CSIR-Indian Institute of Toxicology Research, Lucknow-226001 (India)] [Fibre Toxicology, CSIR-Indian Institute of Toxicology Research, Lucknow-226001 (India); Alrokayan, Salman A. [King Abdullah Institute for Nanotechnology, King Saud University, Riyadh 11451 (Saudi Arabia)] [King Abdullah Institute for Nanotechnology, King Saud University, Riyadh 11451 (Saudi Arabia); Siddiqui, Maqsood A.; Musarrat, Javed; Al-Khedhairy, Abdulaziz A. [Department of Zoology, College of Science, King Saud University, Riyadh 11451 (Saudi Arabia)] [Department of Zoology, College of Science, King Saud University, Riyadh 11451 (Saudi Arabia)
Risk Management for Sodium Fast Reactors.
Accident management is an important component to maintaining risk at acceptable levels for all complex systems, such as nuclear power plants. With the introduction of self - correcting, or inherently safe, reactor designs the focus has shifted from management by operators to allowing the syste m's design to manage the accident. While inherently and passively safe designs are laudable, extreme boundary conditions can interfere with the design attributes which facilitate inherent safety , thus resulting in unanticipated and undesirable end states. This report examines an inherently safe and small sodium fast reactor experiencing a beyond design basis seismic event with the intend of exploring two issues : (1) can human intervention either improve or worsen the potential end states and (2) can a Bayes ian Network be constructed to infer the state of the reactor to inform (1). ACKNOWLEDGEMENTS The author s would like to acknowledge the U.S. Department of E nergy's Office of Nuclear Energy for funding this research through Work Package SR - 14SN100303 under the Advanced Reactor Concepts program. The authors also acknowledge the PRA teams at A rgonne N ational L aborator y , O ak R idge N ational L aborator y , and I daho N ational L aborator y for their continue d contributions to the advanced reactor PRA mission area.
Denman, Matthew R; Groth, Katrina; Cardoni, Jeffrey N; Wheeler, Timothy A.
Sodium Bearing Waste Processing Alternatives Analysis
A multidisciplinary team gathered to develop a BBWI recommendation to DOE-ID on the processing alternatives for the sodium bearing waste in the INTEC Tank Farm. Numerous alternatives were analyzed using a rigorous, systematic approach. The data gathered were evaluated through internal and external peer reviews for consistency and validity. Three alternatives were identified to be top performers: Risk-based Calcination, MACT to WIPP Calcination and Cesium Ion Exchange. A dual-path through early Conceptual design is recommended for MACT to WIPP Calcination and Cesium Ion Exchange since Risk-based Calcination does not require design. If calcination alternatives are not considered based on giving Type of Processing criteria significantly greater weight, the CsIX/TRUEX alternative follows CsIX in ranking. However, since CsIX/TRUEX shares common uncertainties with CsIX, reasonable backups, which follow in ranking, are the TRUEX and UNEX alternatives. Key uncertainties must be evaluated by the decision-makers to choose one final alternative. Those key uncertainties and a path forward for the technology roadmapping of these alternatives is provided.
Murphy, James Anthony; Palmer, Brent J; Perry, Keith Joseph
The objective of the present research work is to synthesize transparent, hydrophobic, monolithic silica aerogels with ultralow density by using supercritical drying process. The effect of phenyltrimethoxysilane as a hydrophobic reagent on the physicochemical properties of the silica aerogels has been studied. The total processing time for the synthesis of monolithic silica aerogels minimized to 29 h which was ~2 days. We have succeeded to get ultralow density of the silica aerogels as low as 24 Kgm-3 with 165 � water droplet contact angle. The ultralow density affects the thermal conductivity of the silica aerogels.
Kavale Mahendra S; Mahadik D. B; Parale V. G; Mane P. B; Vhatkar R. S; A. Venkateswara Rao; Wagh P. B; Satish C. Gupta
Encapsulated in silica: genome, proteome and physiology of the thermophilic bacterium Anoxybacillus flavithermus
Gram-positive bacteria of the genus Anoxybacillus have been found in diverse thermophilic habitats, such as geothermal hot springs and manure, and in processed foods such as gelatin and milk powder. Anoxybacillus flavithermus is a facultatively anaerobic bacterium found in super-saturated silica solutions and in opaline silica sinter. The ability of A. flavithermus to grow in super-saturated silica solutions makes it an ideal subject to study the processes of sinter formation, which might be similar to the biomineralization processes that occurred at the dawn of life. We report here the complete genome sequence of A. flavithermus strain WK1, isolated from the waste water drain at the Wairakei geothermal power station in New Zealand. It consists of a single chromosome of 2,846,746 base pairs and is predicted to encode 2,863 proteins. In silico genome analysis identified several enzymes that could be involved in silica adaptation and biofilm formation, and their predicted functions were experimentally validated in vitro. Proteomic analysis confirmed the regulation of biofilm-related proteins and crucial enzymes for the synthesis of long-chain polyamines as constituents of silica nanospheres. Microbial fossils preserved in silica and silica sinters are excellent objects for studying ancient life, a new paleobiological frontier. An integrated analysis of the A. flavithermus genome and proteome provides the first glimpse of metabolic adaptation during silicification and sinter formation. Comparative genome analysis suggests an extensive gene loss in the Anoxybacillus/Geobacillus branch after its divergence from other bacilli.
Saw, Jimmy H [Los Alamos National Laboratory; Mountain, Bruce W [NEW ZEALAND; Feng, Lu [NANKAI UNIV; Omelchenko, Marina V [NCBI/NLM/NIH; Hou, Shaobin [UNIV OF HAWAII; Saito, Jennifer A [UNIV OF HAWAII; Stott, Matthew B [NEW ZEALAND; Li, Dan [NANKAI UNIV; Zhao, Guang [NANKAI UNIV; Wu, Junli [NANKAI UNIV; Galperin, Michael Y [NCBI/NLM/NIH; Koonin, Eugene V [NCBI/NLM/NIH; Makarova, Kira S [NCBI/NLM/NIH; Wolf, Yuri I [NCBI/NLM/NIH; Rigden, Daniel J [UNIV OF LIVERPOOL; Dunfield, Peter F [UNIV OF CALGARY; Wang, Lei [NANKAI UNIV; Alam, Maqsudul [UNIV OF HAWAII
Loop simulation capability for sodium-cooled systems
A one-dimensional loop simulation capability has been implemented in the thermal-hydraulic analysis code, THERMIT-4E. This code had been used to simulate and investigate flow in test sections of experimental sodium loops ...
Adekugbe, Oluwole A.
aged sodium borophosphate: Topics by E-print Network
ultraviolet flux will produce a similar variation in the column of neutral sodium for a fixed mass flux and density. However, if the cold gas is in pressure equilibrium with a hot...
aqueous sodium chloride: Topics by E-print Network
made with either sodium chloride or potassium chloride. The addition of 75 or 150 porn N02 did not lower plate counts (P&0. 05... Kayfus, Timothy Jon 2012-06-07 58 Systematic...
Reactor protection system design alternatives for sodium fast reactors
Historically, unprotected transients have been viewed as design basis events that can significantly challenge sodium-cooled fast reactors. The perceived potential consequences of a severe unprotected transient in a ...
DeWitte, Jacob D. (Jacob Dominic)
Probabilistic transient analysis of fuel choices for sodium fast reactors
This thesis presents the implications of using a risk-informed licensing framework to inform the design of Sodium Fast Reactors. NUREG-1860, more commonly known as the Technology Neutral Framework (TNF), is a risk-informed ...
Denman, Matthew R
SLAM: a sodium-limestone concrete ablation model
SLAM is a three-region model, containing a pool (sodium and reaction debris) region, a dry (boundary layer and dehydrated concrete) region, and a wet (hydrated concrete) region. The model includes a solution to the mass, momentum, and energy equations in each region. A chemical kinetics model is included to provide heat sources due to chemical reactions between the sodium and the concrete. Both isolated model as well as integrated whole code evaluations have been made with good results. The chemical kinetics and water migration models were evaluated separately, with good results. Several small and large-scale sodium limestone concrete experiments were simulated with reasonable agreement between SLAM and the experimental results. The SLAM code was applied to investigate the effects of mixing, pool temperature, pool depth and fluidization. All these phenomena were found to be of significance in the predicted response of the sodium concrete interaction. Pool fluidization is predicted to be the most important variable in large scale interactions.
Suo-Anttila, A.J.
Sodium Ion Insertion in Hollow Carbon Nanowires for Battery Applicatio...
B Schwenzer, J Xiao, Z Nie, LV Saraf, Z Yang, and J Liu.2012."Sodium Ion Insertion in Hollow Carbon Nanowires for Battery Applications."Nano Letters 12(7):37833787....
Hydrogen and oxygen adsorption stoichiometries on silica supported ruthenium nanoparticles
Treatment under H{sub 2} at 300 C of Ru(COD)(COT) dispersed on silica yields 2 nm ruthenium nanoparticles, [Ru{sub p}/SiO{sub 2}], according to EXAFS, HRTEM and XPS. H{sub 2} adsorption measurements on [Ru{sub p}/SiO{sub 2}] in the absence of O{sub 2} show that Ru particles adsorb up to ca. 2 H per surface ruthenium atoms (2H/Ru{sub s}) on various samples; this technique can therefore be used to measure the dispersion of Ru particles. In contrast, O{sub 2} adsorption on [Ru{sub p}/SiO{sub 2}] leads to a partial oxidation of the bulk at 25 C, to RuO{sub 2} at 200 C and to sintering upon further reduction under H{sub 2}, showing that O{sub 2} adsorption cannot be used to measure the dispersion of Ru particles.
Berthoud, Romain; Delichere, Pierre; Gajan, David; Lukens, Wayne; Pelzer, Katrin; Basset, Jean-Marie; Candy, Jean-Pierre; Coperet, Christophe
Mechanical Loss in Tantala/Silica Dielectric Mirror Coatings
Current interferometric gravitational wave detectors use test masses with mirror coatings formed from multiple layers of dielectric materials, most commonly alternating layers of SiO2 (silica) and Ta2O5 (tantala). However, mechanical loss in the Ta2O5/SiO2 coatings may limit the design sensitivity for advanced detectors. We have investigated sources of mechanical loss in the Ta2O5/SiO2 coatings, including loss associated with the coating-substrate interface, with the coating-layer interfaces, and with the bulk material. Our results indicate that the loss is associated with the bulk coating materials and that the loss of Ta2O5 is substantially larger than that of SiO2.
Steven D. Penn; Peter H. Sneddon; Helena Armandula; Joseph C. Betzwieser; Gianpietro Cagnoli; Jordan Camp; D. R. M. Crooks; Martin M. Fejer; Andri M. Gretarsson; Gregory M. Harry; Jim Hough; Scott E. Kittelberger; Michael J. Mortonson; Roger Route; Sheila Rowan; Christophoros C. Vassiliou
Studies of Immobilized Homogeneous Metal Catalysts on Silica Supports
The tethered, chiral, chelating diphosphine rhodium complex, which catalyzes the enantioselective hydrogenation of methyl-{alpha}-acetamidocinnamate (MAC), has the illustrated structure as established by {sup 31}P NMR and IR studies. Spectral and catalytic investigations also suggest that the mechanism of action of the tethered complex is the same as that of the untethered complex in solution. The rhodium complexes, [Rh(COD)H]{sub 4}, [Rh(COD){sub 2}]{sup +}BF{sub 4}{sup -}, [Rh(COD)Cl]{sub 2}, and RhCl{sub 3} {center_dot} 3H{sub 2}O, adsorbed on SiO{sub 2} are optimally activated for toluene hydrogenation by pretreatment with H{sub 2} at 200 C. The same complexes on Pd-SiO{sub 2} are equally active without pretreatments. The active species in all cases is rhodium metal. The catalysts were characterized by XPS, TEM, DRIFTS, and mercury poisoning experiments. Rhodium on silica catalyzes the hydrogenation of fluorobenzene to produce predominantly fluorocyclohexane in heptane and 1,2-dichloroethane solvents. In heptane/methanol and heptane/water solvents, hydrodefluorination to benzene and subsequent hydrogenation to cyclohexane occurs exclusively. Benzene inhibits the hydrodefluorination of fluorobenzene. In DCE or heptane solvents, fluorocyclohexane reacts with hydrogen fluoride to form cyclohexene. Reaction conditions can be chosen to selectively yield fluorocyclohexane, cyclohexene, benzene, or cyclohexane. The oxorhenium(V) dithiolate catalyst [-S(CH{sub 2}){sub 3}s-]Re(O)(Me)(PPh{sub 3}) was modified by linking it to a tether that could be attached to a silica support. Spectroscopic investigation and catalytic oxidation reactivity showed the heterogenized catalyst's structure and reactivity to be similar to its homogeneous analog. However, the immobilized catalyst offered additional advantages of recyclability, extended stability, and increased resistance to deactivation.
Keith James Stanger
Synthesis and characterization of barium ferrite�silica nanocomposites
In this work, we prepared barium ferrite-silica (BaM-SiO{sub 2}) nanocomposites of different molar ratios by high-energy ball milling, followed by heat-treatment at different temperatures. The microstructure, morphology and magnetic properties were characterized for different synthesis conditions by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM). The results indicate that 15 h of milling was enough to avoid the generation of hematite phase and to get a good dispersion of barium ferrite particles in the ceramic matrix. For milling periods beyond 15 h and heat treatment above 900 �C, the XRD patterns showed the presence of hematite phase caused by the decomposition of BaM. The agglomerate size observed through SEM analysis was around 150 nm with a good BaM dispersion into the SiO{sub 2} matrix. The highest saturation magnetization (Ms) value obtained was 43 emu/g and the corresponding coercivity (Hc) value of 3.4 kOe for the composition 60BaM-40SiO{sub 2} milled for 15 h and heat treated at 900 �C. This coercivity value is acceptable for the application in magnetic recording media. Highlights: � Barium ferrite�silica nanocomposites were prepared by high energy ball milling. � Optimal processing time is 15 h milling and heat treatment at 900 �C. � This is enough to avoid the generation of hematite phase. � Obtain good dispersion of barium ferrite particles in the ceramic matrix � Above this processing time shows the presence of increased amount of hematite.
Aguilar-Gonz�lez, M.A.; Mendoza-Su�rez, G.; Padmasree, K.P., E-mail: email@example.com
The Salt or Sodium Chloride Content of Feeds
of Sodium Chloride.--In order to test the recovery of added salt, several molasses feeds were selected, weighed out, and varying amounts of salt added, in the form of a N/10 solution of sodium chloride. The salt was added hy a different person from... ............................... . . Preliminary ~vork on laboratory methocls ........ . . ............................... Laboratory method adopted.. ............................. Tests of the laboratory niethod. ................... Application of the methold to feed mixtures...
Fraps, G. S. (George Stronach); Lomanitz, S. (Sebastian)
Advanced sodium fast reactor accident source terms : research needs.
An expert opinion elicitation has been used to evaluate phenomena that could affect releases of radionuclides during accidents at sodium-cooled fast reactors. The intent was to identify research needed to develop a mechanistic model of radionuclide release for licensing and risk assessment purposes. Experts from the USA, France, the European Union, and Japan identified phenomena that could affect the release of radionuclides under hypothesized accident conditions. They qualitatively evaluated the importance of these phenomena and the need for additional experimental research. The experts identified seven phenomena that are of high importance and have a high need for additional experimental research: High temperature release of radionuclides from fuel during an energetic eventEnergetic interactions between molten reactor fuel and sodium coolant and associated transfer of radionuclides from the fuel to the coolantEntrainment of fuel and sodium bond material during the depressurization of a fuel rod with breached claddingRates of radionuclide leaching from fuel by liquid sodiumSurface enrichment of sodium pools by dissolved and suspended radionuclidesThermal decomposition of sodium iodide in the containment atmosphereReactions of iodine species in the containment to form volatile organic iodides. Other issues of high importance were identified that might merit further research as development of the mechanistic model of radionuclide release progressed.
Powers, Dana Auburn; Clement, Bernard [IRSN/DPAM.SEMIC Bt 702, Saint-Paul-lez-Durance, France; Denning, Richard [Ohio State University, Columbus, OH; Ohno, Shuji [Japan Atomic Energy Agency, Ibaraki, Japan; Zeyen, Roland [Institute for Energy Petten, Saint-Paul-lez-Durance, France
Classification : Original Article VOLTAGE-GATED SODIUM CHANNELS POTENTIATE THE INVASIVE
- gated sodium channels in non-small-cell lung cancer cell lines. Functional voltage-gated sodium channels cancerous cell lines H23, H460 and Calu-1 possess functional sodium channels while normal and weakly metastatic cell lines do not. While all the cell lines expressed mRNA for numerous sodium channel isoforms
Method of and apparatus for removing silicon from a high temperature sodium coolant
A method of and system for removing silicon from a high temperature liquid sodium coolant system for a nuclear reactor. The sodium is cooled to a temperature below the silicon saturation temperature and retained at such reduced temperature while inducing high turbulence into the sodium flow for promoting precipitation of silicon compounds and ultimate separation of silicon compound particles from the liquid sodium.
Yunker, Wayne H. (Richland, WA); Christiansen, David W. (Kennewick, WA)
KrF- and ArF-excimer-laser-induced absorption in silica glasses produced by melting synthetic silica powder
KrF- and ArF-excimer-laser-induced absorption of silica glasses produced by electric melting and flame fusion of synthetic silica powder were investigated. The growth of KrF-laser-induced absorption was more gradual than that of ArF-laser-induced absorption. Induced absorption spectra exhibited a peak at about 5.8 eV, of which the position and width differed slightly among samples and laser species. Widths of ArF-laser-induced absorption spectra were wider than those of KrF-laser-induced spectra. KrF-laser-induced absorption is reproducible by two Gaussian absorption bands peaking at 5.80 eV with full width at half maximum (FWHM) of 0.62 eV and at 6.50 eV with FWHM of 0.74 eV. For reproduction of ArF-laser-induced absorption, Gaussian bands at 5.41 eV with FWHM of 0.62 eV was necessary in addition to components used for reproducing KrF-laser-induced absorption. Based on the discussion of the change of defect structures evaluated from change of absorption components, we proposed that the precursor of the 5.8-eV band ascribed to E Prime center ({identical_to}Si{center_dot}) is {identical_to}Si-H HO-Si{identical_to} structures formed by the reaction between strained Si-O-Si bonds and interstitial H{sub 2} molecules during the irradiation.
Kuzuu, Nobu; Sasaki, Toshiya; Kojima, Tatsuya [Department of Applied Physics, University of Fukui, 3-9-1 Bunkyo, Fukui-shi, Fukui 910-8507 (Japan); Tanaka, Jun-ichiro; Nakamura, Takayuki; Horikoshi, Hideharu [Tosoh SGM Corp., 4555 Kaisei-cho, Shunan-shi, Yamaguchi 746-0006 (Japan)
Ammoniated silica-alumina gel and catalyst containing the same and processes for producing same
This invention relates to hydrothermally treated silica-alumina cogels resulting in a reduction in the NH/sub 4/ content of the gel and the employment of such gels as cracking catalysts.
Alafandi, H.; Stamires, D.
E-Print Network 3.0 - aluminate-silica fume mixtures Sample Search...
< 1 2 3 4 5 > >> Page: << < 1 2 3 4 5 > >> 21 Carbon 39 (2001) 19952001 Silane-treated carbon fiber for reinforcing cement Summary: -treated carbon fibers and silane-treated silica...
E-Print Network 3.0 - aperture fused silica Sample Search Results
using a Kaufman type ion source to figure 8 cm diameter fused silica and silicon carbide samples... cases are shown in Table 1 and Figure 1. Using a 3 cm diameter Ion Tech...
ORNL devises recipe to fine-tune diameter of silica rods | ornl...
the stage for advances in anti-reflective solar cells, computer monitors, TV screens, eye glasses and more. The goal of fabricating fixed-size one-dimensional silica structures...
Method for inhibiting silica precipitation and scaling in geothermal flow systems
A method for inhibiting silica scaling and precipitation in geothermal flow systems by on-line injection of low concentrations of cationic nitrogen-containing compounds, particularly polymeric imines, polymeric amines, and quaternary ammonium compounds is described.
Harrar, J.E.; Lorensen, L.E.; Locke, F.E.
Fundamental Studies on Polymer and Organic-Inorganic Hybrid Nanoparticles Reinforced Silica Aerogels.
??The objective of this research was to reinforce silica aerogels using functional organic-inorganic hybrid nanoparticles, silane end-capped polyurethane oligomer and chain extended polymer, and self-crosslinkable� (more)
Duan, Yannan
Study of the Behavior of a Commercial Scale Inhibitor on Silica Sand
squeeze lifetimes in order to minimize the number of treatments, thus reducing the cost. The objective of this thesis is to study the adsorption of the commercial scale inhibitor SI onto silica sand. By investigating this intrinsic phenomenon, an optimized...
Vaca Bustamante, Victor
E-Print Network 3.0 - abundant circumstellar silica Sample Search...
67 doi:10.1016S0016-7037(03)00461-7 Pristine presolar silicon carbide Summary: silica coatings of as much as several tens of nm thickness, perhaps due to oxidation of the Si......
E-Print Network 3.0 - alcali-silica reactions mechanisms Sample...
results for: alcali-silica reactions mechanisms Page: << < 1 2 3 4 5 > >> 1 GTQ, Chemistry 212, Dr. Glaser, FS96 --1 --GTQ on Baeyer-Villiger Reaction. (20 points,...
Laser-induced fluorescence of fused silica irradiated by ArF excimer laser
Laser-induced fluorescence (LIF) of high-purity fused silica irradiated by ArF excimer laser is studied experimentally. LIF bands of the fused silica centered at 281 nm, 478 nm, and 650 nm are observed simultaneously. Furthermore, the angular distribution of the three fluorescence peaks is examined. Microscopic image of the laser modified fused silica indicates that scattering of the generated fluorescence by laser-induced damage sites is the main reason for the angular distribution of LIF signals. Finally, the dependence of LIF signals intensities of the fused silica on laser power densities is presented. LIF signals show a squared power density dependence, which indicates that laser-induced defects are formed mainly via two-photon absorption processes.
Zhang Haibo [Shanghai Key Laboratory of All Solid-state Laser and Applied Techniques, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Science, Shanghai 201800 (China); Graduate University of Chinese Academy of Science, Beijing 100049 (China); Yuan Zhijun; Zhou Jun; Dong Jingxing; Wei Yunrong; Lou Qihong [Shanghai Key Laboratory of All Solid-state Laser and Applied Techniques, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Science, Shanghai 201800 (China)
A method for inhibiting silica scaling and precipitation in geothermal flow systems by on-line injection of low concentrations of cationic nitrogen-containing compounds, particularly polymeric imines, polymeric amines, and quaternary ammonium compounds.
Harrar, Jackson E. (Castro Valley, CA); Lorensen, Lyman E. (Orinda, CA); Locke, Frank E. (Lafayette, CA)
E-Print Network 3.0 - ash-silica fume pastes Sample Search Results
; Engineering 100 By-Products Utilization Summary: of Recycled Aggregates in Self-Compacting4 Concrete", Fly Ash, Silica Fume, Slag and Natural Pozzolans... (0.00028 in.). For...
Treatment of domestic wastewater for reuse with activated silica and magnesia
which are of concern in treat- ment for potable purposes are organics and trace inorganics. This research project was conducted in an attempt to determine if organic oxides such as activated silica and magnesia in various combinations with alum... in Wastewater Toxic Inorganics in Wastewater Existing Technology Coagulation and Flocculation Lime Coagulation . . ~ Alum Coagulation . ~ ~ ~ ~ Activated Silica Magnesia 5 6 8 9 10 13 14 15 16 III EXPERIMENTAL PLAN Was tewater ~ ~ ~ ~ ~ Jar...
Lindner, John Howard
Luminescent studies of fluorescent chromophore-doped silica aerogels for flat panel display applications
The remarkable optical and electronic properties of doped and undoped silica aerogels establish their utility as unique, mulitfunctional host materials for fluorescent dyes and other luminescent materials for display and imaging applications. We present results on the photoluminescence, absorption, and photoluminescence excitation spectra of undoped silica aerogels and aerogels doped with Er{sup 3+}, rhodamine 6G (R6G), and fluorescein. 4 refs., 12 figs.
Glauser, S.A.C. [California Univ., Davis, CA (United States). Dept. of Applied Science; Lee, H.W.H. [Lawrence Livermore National Lab., CA (United States)
Synthesis of Novel Polypeptide-Silica Hybrid Materials through Surface-Initiated N-carboxyanhydride Polymerization
synthesis routes derived from sol-gel chemistry .......................... 4 1.3 Polymerization behavior of aqueous silica ............................................................ 11 1.4 Simulated structures from various growth models... are still used; however, the use of sol-gel chemistry for silica matrix construction permits the greatest degree of design flexibility and variety of materials that can be synthesized. Common synthesis techniques derived from sol-gel chemistry have been...
Lunn, Jonathan D.
The effect of lattice temperature on surface damage in fused silica optics
We examine the effect of lattice temperature on the probability of surface damage initiation for 355nm, 7ns laser pulses for surface temperatures below the melting point to temperatures well above the melting point of fused silica. At sufficiently high surface temperatures, damage thresholds are dramatically reduced. Our results indicate a temperature activated absorption and support the idea of a lattice temperature threshold of surface damage. From these measurements, we estimate the temperature dependent absorption coefficient for intrinsic silica.
Bude, J; Guss, G; Matthews, M; Spaeth, M L
Silica and acid-detergent fiber content of five varieties of bermudagrass
SILICA &ID ACID-DETERGENT FIBER CONTENT OF FIVE VARIETIES OF BERMUDAGRASS A Thesis by FREDERICK MICHAEL JUNGMAN Submitted to the Graduate College of Texas A&M Uniuersity in partial fulfillment of the requirements for the degree of MASTER... OF SCIENCE August 1971 Major Subject: Agronomy SILICA AND ACID-DETERGENT FIBER CONTENT 01' FIVE VARIETIES OF BEI~DAGRASS A Thesis by FREDERICK MICHAEL OUNGMAN Approved as to style and content by: (Chai rman of Coamd t tee) (llead of. Department...
Jungman, Frederick Michael
Templated Control of Au nanospheres in Silica Nanowires
The formation of regularly-spaced metal nanostructures in selectively-placed insulating nanowires is an important step toward realization of a wide range of nano-scale electronic and opto-electronic devices. Here we report templated synthesis of Au nanospheres embedded in silica nanowires, with nanospheres consistently spaced with a period equal to three times their diameter. Under appropriate conditions, nanowires form exclusively on Si nanostructures because of enhanced local oxidation and reduced melting temperatures relative to templates with larger dimensions. We explain the spacing of the nanospheres with a general model based on a vapor-liquid-solid mechanism, in which an Au/Si alloy dendrite remains liquid in the nanotube until a critical Si concentration is achieved locally by silicon oxide-generated nanowire growth. Additional Si oxidation then locally reduces the surface energy of the Au-rich alloy by creating a new surface with minimum area inside of the nanotube. The isolated liquid domain subsequently evolves to become an Au nanosphere, and the process is repeated.
Tringe, J W; Vanamu, G; Zaidi, S H
Implantation conditions for diamond nanocrystal formation in amorphous silica
We present a study of carbon ion implantation in amorphous silica, which, followed by annealing in a hydrogen-rich environment, leads to preferential formation of carbon nanocrystals with cubic diamond (c-diamond), face-centered cubic (n-diamond), or simple cubic (i-carbon) carbon crystal lattices. Two different annealing treatments were used: furnace annealing for 1 h and rapid thermal annealing for a brief period, which enables monitoring of early nucleation events. The influence of implanted dose and annealing type on carbon and hydrogen concentrations, clustering, and bonding were investigated. Rutherford backscattering, elastic recoil detection analysis, infrared spectroscopy, transmission electron microscopy, selected area electron diffraction, ultraviolet-visible absorption measurements, and Raman spectroscopy were used to study these carbon formations. These results, combined with the results of previous investigations on similar systems, show that preferential formation of different carbon phases (diamond, n-diamond, or i-carbon) depends on implantation energy, implantation dose, and annealing conditions. Diamond nanocrystals formed at a relatively low carbon volume density are achieved by deeper implantation and/or lower implanted dose. Higher volume densities led to n-diamond and finally to i-carbon crystal formation. This observed behavior is related to damage sites induced by implantation. The optical properties of different carbon nanocrystal phases were significantly different.
Buljan, Maja; Radovic, Iva Bogdanovic; Desnica, Uros V.; Ivanda, Mile; Jaksic, Milko [Ruder Boskovic Institute, P.O. Box 180, 10002 Zagreb (Croatia); Saguy, Cecile; Kalish, Rafi [Physics Department and Solid State Institute, Technion, Haifa 32000 (Israel); Djerdj, Igor [Department of Materials, Swiss Federal Institute of Technology (ETH) Zuerich, Wolfgang-Pauli-Str. 10, CH-8093 Zuerich (Switzerland); Tonejc, Andelka [Faculty of Science, Department of Physics, University of Zagreb, 10000 Zagreb (Croatia); Gamulin, Ozren [School of Medicine, Zagreb University, 10000 Zagreb (Croatia)
Numerical Methodology to Evaluate Fast Reactor Sodium Combustion
In the present study, a numerical methodology for sodium combustion has been developed for the safety evaluation of a liquid-metal-cooled fast reactor. The methodology includes a fast-running zone model computer program for safety evaluation, a field model program for multidimensional thermal hydraulics, and a chemical reaction analysis program based on chemical equilibrium theory. Two recently performed experiments have been analyzed using the computer programs, and the numerical results are in good agreement with the experiments. Although sodium combustion is a complex phenomenon, use of these computer programs gives better understanding of the coupled thermal hydraulics and chemical reaction.
Yamaguchi, Akira; Takata, Takashi; Okano, Yasushi [Japan Nuclear Cycle Development Institute (Japan)
The magnesium nutrition of cotton as influenced by sodium
1964 Major Subject. Plant Physic logy THE MAGNESIUM NUTRITION OF COTTON AS INFLUENCED BY SODIUM A Thesis By MERVYN M. THENABADU Approved as to style and content by: Chairman of Commi. e Nun Head of Department Member Mem, er Member Member... REVIEW OF LITERATURE (a) Sodium as a plant nutrient (b) I'he role of magnesium in plant nutrition MATERIALS AND METHODS RESUL:S DISCUSSION 13 21 24 (a) The effect of treatments on grcwth and reproduction (b) The effect of treatments on the ccr...
Thenabadu, Mervyn Wellesly
Aluminum Zintl anion moieties within sodium aluminum clusters
Through a synergetic combination of anion photoelectron spectroscopy and density functional theory based calculations, we have established that aluminum moieties within selected sodium-aluminum clusters are Zintl anions. Sodium�aluminum cluster anions, Na{sub m}Al{sub n}{sup ?}, were generated in a pulsed arc discharge source. After mass selection, their photoelectron spectra were measured by a magnetic bottle, electron energy analyzer. Calculations on a select sub-set of stoichiometries provided geometric structures and full charge analyses for both cluster anions and their neutral cluster counterparts, as well as photodetachment transition energies (stick spectra), and fragment molecular orbital based correlation diagrams.
Wang, Haopeng; Zhang, Xinxing; Ko, Yeon Jae; Grubisic, Andrej; Li, Xiang; Gantef�r, Gerd; Bowen, Kit H., E-mail: firstname.lastname@example.com, E-mail: email@example.com, E-mail: email@example.com [Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Schn�ckel, Hansgeorg [Institute of Inorganic Chemistry, Karlsruhe Institute of Technology, 76128 Karlsruhe (Germany)] [Institute of Inorganic Chemistry, Karlsruhe Institute of Technology, 76128 Karlsruhe (Germany); Eichhorn, Bryan W. [Department of Chemistry, University of Maryland at College Park, College Park, Maryland 20742 (United States)] [Department of Chemistry, University of Maryland at College Park, College Park, Maryland 20742 (United States); Lee, Mal-Soon; Jena, P. [Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284 (United States)] [Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284 (United States); Kandalam, Anil K., E-mail: firstname.lastname@example.com, E-mail: email@example.com, E-mail: email@example.com [Department of Physics, West Chester University of Pennsylvania, West Chester, Pennsylvania 19383 (United States); Kiran, Boggavarapu, E-mail: firstname.lastname@example.com, E-mail: email@example.com, E-mail: firstname.lastname@example.com [Department of Chemistry, McNeese State University, Lake Charles, Louisiana 70609 (United States)] [Department of Chemistry, McNeese State University, Lake Charles, Louisiana 70609 (United States)
Ion Recognition Approach to Volume Reduction of Alkaline Tank Waste by Separation and Recycle of Sodium Hydroxide and Sodium Nitrate
This research has focused on new liquid-liquid extraction chemistry applicable to separation of major sodium salts from alkaline tank waste. It was the overall goal to provide the scientific foundation upon which the feasibility of liquid-liquid extraction chemistry for bulk reduction of the volume of tank waste can be evaluated. Sodium hydroxide represented the initial test case and primary focus. It is a primary component of the waste1 and has the most value for recycle. A full explanation of the relevance of this research to USDOE Environmental Management needs will be given in the Relevance, Impact, and Technology Transfer section below. It should be noted that this effort was predicated on the need for sodium removal primarily from low-activity waste, whereas evolving needs have shifted attention to volume reduction of the high-activity waste. The results of the research to date apply to both applications, though treatment of high-activity wastes raises new questions that will be addressed in the renewal period. Toward understanding the extractive chemistry of sodium hydroxide and other sodium salts, it was the intent to identify candidate extractants and determine their applicable basic properties regarding selectivity, efficiency, speciation, and structure. A hierarchical strategy was to be employed in which the type of liquid-liquid-extraction system varied in sophistication from simple, single-component solvents to solvents containing designer host molecules. As an aid in directing this investigation toward addressing the fundamental questions having the most value, a conceptualization of an ideal process was advanced. Accordingly, achieving adequate selectivity for sodium hydroxide represented a primary goal, but this result is worthwhile for waste applications only if certain conditions are met.
Moyer, Bruce A.; Marchand, Alan P.; Bonnesen, Peter V.; Bryan, Jeffrey C.; Haverlock, Tamara J.
. 100 calcium while rations 3 and4contained 3.85 p. 100 calcium. Sodium bicarbonate was added at a level. The duodenum was entered at the top of the loop and the electrode tip immersed its full length down the posterior side of the loop. The #12;mid-intestinal reading was taken with the incision at approximately
Electrochemical Recovery of Sodium Hydroxide from Alkaline Salt Solution
A statistically designed set of tests determined the effects of current density, temperature, and the concentrations of nitrate/nitrite, hydroxide and aluminate on the recovery of sodium as sodium hydroxide (caustic) from solutions simulating those produced from the Savannah River Site (SRS) In-Tank Precipitation process. These tests included low nitrate and nitrite concentrations which would be produced by electrolytic nitrate/nitrite destruction. The tests used a two compartment electrochemical cell with a Nafion Type 324 ion-exchange membrane. Caustic was successfully recovered from the waste solutions. Evaluation of the testing results indicated that the transport of sodium across the membrane was not significantly affected by any of the varied parameters. The observed variance in the sodium flux is attributed to experimental errors and variations in the performance characteristics of individual pieces of the organic-based Nafion membrane.Additional testing is recommended to determine the maximum current density, to evaluate the chemical durability of the organic membrane as a function of current density and to compare the durability and performance characteristics of the organic-based Nafion membrane with that of other commercially available organic membranes and the inorganic class of membranes under development by Ceramatec and PNNL.
Hobbs, D.T. [Westinghouse Savannah River Company, AIKEN, SC (United States); Edwards, T.B.
Process for making boron nitride using sodium cyanide and boron
This a very simple process for making boron nitride by mixing sodium cyanide and boron phosphate and heating the mixture in an inert atmosphere until a reaction takes place. The product is a white powder of boron nitride that can be used in applications that require compounds that are stable at high temperatures and that exhibit high electrical resistance.
Bamberger, Carlos E. (Oak Ridge, TN)
ORIGINAL RESEARCH Systematic family-wide analysis of sodium bicarbonate
ORIGINAL RESEARCH Systematic family-wide analysis of sodium bicarbonate cotransporter NBCn1/SLC4A7/NBCn1 pulled down syntrophin c2 and con- versely GST/syntrophin c2 pulled down NBCn1. Moreover normally moves Na+ and HCO3 �? into cells and protects intracel- lular pH (pHi) from falling below normal
Hall, Randy A
Laboratory-scale sodium-carbonate aggregate concrete interactions. [LMFBR
A series of laboratory-scale experiments was made at 600/sup 0/C to identify the important heat-producing chemical reactions between sodium and carbonate aggregate concretes. Reactions between sodium and carbonate aggregate were found to be responsible for the bulk of heat production in sodium-concrete tests. Exothermic reactions were initiated at 580+-30/sup 0/C for limestone and dolostone aggregates as well as for hydrated limestone concrete, and at 540+-10/sup 0/C for dehydrated limestone concrete, but were ill-defined for dolostone concrete. Major reaction products included CaO, MgO, Na/sub 2/CO/sub 3/, Na/sub 2/O, NaOH, and elemental carbon. Sodium hydroxide, which forms when water is released from cement phases, causes slow erosion of the concrete with little heat production. The time-temperature profiles of these experiments have been modeled with a simplified version of the SLAM computer code, which has allowed derivation of chemical reaction rate coefficients.
Westrich, H.R.; Stockman, H.W.; Suo-Anttila, A.
Method of Manufacturing Micro-Disperse Particles of Sodium Borohydride
A compact solid source of hydrogen gas, where the gas is generated by contacting water with micro-disperse particles of sodium borohydride in the presence of a catalyst, such as cobalt or ruthenium. The micro-disperse particles can have a substantially uniform diameter of 1-10 microns, and preferably about 3-5 microns. Ruthenium or cobalt catalytic nanoparticles can be incorporated in the micro-disperse particles of sodium borohydride, which allows a rapid and complete reaction to occur without the problems associated with caking and scaling of the surface by the reactant product sodium metaborate. A closed loop water management system can be used to recycle wastewater from a PEM fuel cell to supply water for reacting with the micro-disperse particles of sodium borohydride in a compact hydrogen gas generator. Capillary forces can wick water from a water reservoir into a packed bed of micro-disperse fuel particles, eliminating the need for using an active pump.
Kravitz, Stanley H. (Placitas, NM); Hecht, Andrew M. (Sandia Park, NM); Sylwester. Alan P. (Albuquerque, NM); Bell, Nelson S. (Albuquerque, NM)
Method of generating hydrogen gas from sodium borohydride
Kravitz, Stanley H. (Placitas, NM); Hecht, Andrew M. (Sandia Park, NM); Sylwester, Alan P. (Albuquerque, NM); Bell, Nelson S. (Albuquerque, NM)
Immobilization of sodium nitrate waste with polymers: Topical report
This report describes the development of solidification systems for sodium nitrate waste. Sodium nitrate waste was solidified in the polymers polyethylene, polyester-styrene (PES), and water-extendible polyester-styrene (WEP). Evaluations were made of the properties of waste forms containing various amounts of sodium nitrate by leaching immersion in water, measuring compressive strengths and by the EPA Extraction Procedure. Results of the leaching test are presented as cumulative fraction leached (CFL), incremental leaching rate, and average leaching indices (LI). For waste forms containing 30 to 70 wt% sodium nitrate, the CFL ranged from 9.0 x 10/sup -3/ to 7.3 x 10/sup -1/ and the LI from 11 to 7.8. After ninety days immersion in water, the compressive strengths ranged from 720 psi to 2550 psi. The nitrate releases from these samples using the EPA Extraction Procedure were below 500 ppM. The nitrate releases from PES waste forms were similar to those from polyethylene waste forms at the same waste loadings. The compressive yield strengths, measured after ninety-day immersion in water, ranged between 2070 and 7710 psi. In the case of WEP waste forms, only 30 wt% loaded samples passed the immersion test. 23 refs., 24 figs., 12 tabs.
Franz, E.M.; Heiser, J.H. III; Colombo, P.
Compatibility Assessment of Advanced Stainless Steels in Sodium
Type 316L stainless steel capsules containing commercially pure sodium and miniature tensile specimens of HT-UPS (austenitic, 14Cr-16Ni), NF-616 (ferritic/martensitic, 9Cr-2W-0.5Mo), or 316L (austenitic, 17Cr-10Ni-2Mo) stainless steel were exposed at 600 or 700 C for 100 and 400 h as a screening test for compatibility. Using weight change, tensile testing, and metallographic analysis, HT-UPS and 316L were found to be largely immune to changes resulting from sodium exposure, but NF-616 was found susceptible to substantial decarburization at 700 C. Subsequently, two thermal convection loops (TCLs) constructed of 316L and loaded with commercially pure sodium and miniature tensile specimens of HT-UPS and 316L were operated for 2000 h each one between 500 and 650 C, the other between 565 and 725 C at a flow rate of about 1.5 cm/s. Changes in specimen appearance, weight, and tensile properties were observed to be very minor in all cases, and there was no metallographic evidence of microstructure changes, composition gradients, or mass transfer resulting from prolonged exposure in a TCL. Thus, it appears that HT-UPS and 316L stainless steels are similarly compatible with commercially pure sodium under these exposure conditions.
Pawel, Steven J [ORNL
Thickness controlled sol-gel silica films for plasmonic bio-sensing devices
Plasmonics has recently received considerable interest due to its potentiality in many fields as well as in nanobio-technology applications. In this regard, various strategies are required for modifying the surfaces of plasmonic nanostructures and to control their optical properties in view of interesting application such as bio-sensing, We report a simple method for depositing silica layers of controlled thickness on planar plasmonic structures. Tetraethoxysilane (TEOS) was used as silica precursor. The control of the silica layer thickness was obtained by optimizing the sol-gel method and dip-coating technique, in particular by properly tuning different parameters such as pH, solvent concentration, and withdrawal speed. The resulting films were characterized via atomic force microscopy (AFM), Fourier-transform (FT) spectroscopy, and spectroscopic ellipsometry (SE). Furthermore, by performing the analysis of surface plasmon resonances before and after the coating of the nanostructures, it was observed that the position of the resonance structures could be properly shifted by finely controlling the silica layer thickness. The effect of silica coating was assessed also in view of sensing applications, due to important advantages, such as surface protection of the plasmonic structure.
Figus, Cristiana, E-mail: firstname.lastname@example.com; Quochi, Francesco, E-mail: email@example.com; Artizzu, Flavia, E-mail: email@example.com; Saba, Michele, E-mail: firstname.lastname@example.com; Marongiu, Daniela, E-mail: firstname.lastname@example.com; Mura, Andrea; Bongiovanni, Giovanni [Dipartimento di Fisica - University of Cagliari, S.P. Km 0.7, I-09042 Monserrato (Canada) (Italy); Floris, Francesco; Marabelli, Franco; Patrini, Maddalena; Fornasari, Lucia [Dipartimento di Fisica - University of Pavia, Via Agostino Bassi 6, I-27100 Pavia (PV) (Italy); Pellacani, Paola; Valsesia, Andrea [Plasmore S.r.l. -Via Grazia Deledda 4, I-21020 Ranco (Vatican City State, Holy See) (Italy)
NiO-silica based nanostructured materials obtained by microemulsion assisted sol-gel procedure
Graphical abstract: TEM micrograph of NiO/SiO{sub 2} nanoparticles. Highlights: {yields} Microemulsion assisted sol-gel procedure for NiO silica nanomaterials synthesis. {yields} Controlling the size and shape of nanoparticles and avoiding their aggregation. {yields} Narrow band-gap semiconductors (energies <3 eV) absorbing VIS or near-UV light biologically and chemically inert semiconductors entrapping/coating in silica network. {yields} Low cost as the microemulsion is firstly used in water metallic cation extraction. -- Abstract: NiO-silica based materials have been synthesized by microemulsion assisted sol-gel procedure. The versatility of these soft nanotechnology techniques has been exploited in order to obtain different types of nanostructures, such as NiO nanoparticles, NiO silica coated nanoparticles and NiO embedded in silica matrix. These materials have been characterized by adequate structural and morphology techniques: DLS, HR-TEM/SAED, BET, AFM. Optical and semiconducting properties (band-gap values) of the synthesized materials have been quantified by means of VIS-NIR diffuse reflectance spectra, thus demonstrating their applicative potential in various electron transfer phenomena such as photocatalysis, electrochromic thin films, solid oxide fuel cells.
Mihaly, M.; Comanescu, A.F. [University POLITEHNICA Bucharest, Faculty of Applied Chemistry and Materials Science, 1 Polizu, 011061 Bucharest (Romania)] [University POLITEHNICA Bucharest, Faculty of Applied Chemistry and Materials Science, 1 Polizu, 011061 Bucharest (Romania); Rogozea, A.E. [ILIE MURGULESCU Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest (Romania)] [ILIE MURGULESCU Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest (Romania); Vasile, E. [METAV Research and Development, 31 C.A. Rosetti, 020011 Bucharest (Romania)] [METAV Research and Development, 31 C.A. Rosetti, 020011 Bucharest (Romania); Meghea, A., E-mail: firstname.lastname@example.com [University POLITEHNICA Bucharest, Faculty of Applied Chemistry and Materials Science, 1 Polizu, 011061 Bucharest (Romania)
Direct encapsulation of water-soluble drug into silica microcapsules for sustained release applications
Direct encapsulation of water-soluble drug into silica microcapsules was facilely achieved by a sol-gel process of tetraethoxysilane (TEOS) in W/O emulsion with hydrochloric acid (HCl) aqueous solution containing Tween 80 and drug as well as cyclohexane solution containing Span 80. Two water-soluble drugs of gentamicin sulphate (GS) and salbutamol sulphate (SS) were chosen as model drugs. The characterization of drug encapsulated silica microcapsules by scanning electronic microscopy (SEM), FTIR, thermogravimetry (TG) and N{sub 2} adsorption-desorption analyses indicated that drug was successfully entrapped into silica microcapsules. The as-prepared silica microcapsules were uniform spherical particles with hollow structure, good dispersion and a size of 5-10 {mu}m, and had a specific surface area of about 306 m{sup 2}/g. UV-vis and thermogravimetry (TG) analyses were performed to determine the amount of drug encapsulated in the microcapsules. The BJH pore size distribution (PSD) of silica microcapsules before and after removing drug was examined. In vitro release behavior of drug in simulated body fluid (SBF) revealed that such system exhibited excellent sustained release properties.
Wang Jiexin; Wang Zhihui [Key Lab for Nanomaterials, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029 (China); Chen Jianfeng [Key Lab for Nanomaterials, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029 (China); Research Center of the Ministry of Education for High Gravity Engineering and Technology, Beijing University of Chemical Technology, Beijing 100029 (China)], E-mail: email@example.com; Yun, Jimmy [Nanomaterials Technology Pte. Ltd., 28 Ayer Rajah Crescent 03-03, Singapore 139959 (Singapore)
Chemistry of Petroleum Crude Oil Deposits: Sodium Naphthenates 2009 NHMFL Science Highlight for NSF
Chemistry of Petroleum Crude Oil Deposits: Sodium Naphthenates 2009 NHMFL Science Highlight for NSF-355. Chemistry of Petroleum Crude Oil Deposits: Sodium Naphthenates 2009 NHMFL Science Highlight for NSF DMR
Weston, Ken
apical sodium-chloride cotransporter: Topics by E-print Network
g magnesium chloride, 3.24 g magnesium sulfate bromide, 34 mg strontium chloride, 22 mg boric acid, 4 mg sodium silicate, 2.4 mg sodium fluoride, 1.6 mg Bae, Jin-Woo 302 The...
This patent discloses a method of and system for removing silicon from a high temperature liquid sodium coolant system for a nuclear reactor. The sodium is cooled to a temperature below the silicon saturation temperature and retained at such reduced temperature while inducing high turbulence into the sodium flow for promoting precipitation of silicon compounds and ultimate separation of silicon compound particles from the liquid sodium.
Yunker, W.H.; Christiansen, D.W.
Go No-Go Recommendation for Sodium Borohydride for On-Board Vehicular Hydrogen Storage
Fuel Cell Technologies Publication and Product Library (EERE)
Independent review panel recommendation for go/no go decision on use of hydrolysis of sodium borohydride for hydrogen storage.
Moisture sensor based on evanescent wave light scattering by porous sol-gel silica coating
An optical fiber moisture sensor that can be used to sense moisture present in gas phase in a wide range of concentrations is provided, as well techniques for making the same. The present invention includes a method that utilizes the light scattering phenomenon which occurs in a porous sol-gel silica by coating an optical fiber core with such silica. Thus, a porous sol-gel silica polymer coated on an optical fiber core forms the transducer of an optical fiber moisture sensor according to an embodiment. The resulting optical fiber sensor of the present invention can be used in various applications, including to sense moisture content in indoor/outdoor air, soil, concrete, and low/high temperature gas streams.
Tao, Shiquan; Singh, Jagdish P.; Winstead, Christopher B.
Preparation and sintering of silica-doped zirconia by colloidal processing
Silica-doped (SiO{sub 2} = 0--1.0 mass%) zirconia (3 mol% Y{sub 2}O{sub 3}-doped tetragonal ZrO{sub 2}) compacts are prepared from hetero-coagulated and well-dispersed suspensions by colloidal processing. The suspensions are consolidated by a pressure filtration technique. The green density of the compacts consolidated from the well-dispersed suspensions is higher than that from the hetero-coagulated suspensions. The lower density of the latter compacts is improved by a subsequent cold isostatic pressing (CIP) at 400 MPa. The sinterability of the compacts at 1,200 C is greatly affected by the amount of doped silica. The densification and grain growth are hindered by silica doping above 0.3 wt% at 1,200 C. All the compacts are densificated to a relative density of above 99% by sintering at 1,300 C for 2 h.
Uchikoshi, T.; Sakka, Y.; Ozawa, K.; Hiraga, K. [National Research Inst. for Metals, Tsukuba, Ibaraki (Japan)
Self-Assembled Silica Nano-Composite Polymer Electrolytes: Synthesis, Rheology & Electrochemistry
The ultimate objectives of this research are to understand the principles underpinning nano-composite polymer electrolytes (CPEs) and facilitate development of novel CPEs that are low-cost, have high conductivities, large Li+ transference numbers, improved electrolyte-electrode interfacial stability, yield long cycle life, exhibit mechanical stability and are easily processable. Our approach is to use nanoparticulate silica fillers to formulate novel composite electrolytes consisting of surface-modified fumed silica nano-particles in polyethylene oxides (PEO) in the presence of lithium salts. We intend to design single-ion conducting silica nanoparticles which provide CPEs with high Li+ transference numbers. We also will develop low-Mw (molecular weight), high-Mw and crosslinked PEO electrolytes with tunable properties in terms of conductivity, transference number, interfacial stability, processability and mechanical strength
Khan, Saad A.: Fedkiw Peter S.; Baker, Gregory L.
SANS study of interaction of silica nanoparticles with BSA protein and their resultant structure
Small angle neutron scattering (SANS) has been carried out to study the interaction of anionic silica nanoparticles (88 �) with globular protein Bovine Serum Albumin (BSA) (M.W. 66.4 kD) in aqueous solution. The measurements have been carried out on fixed concentration (1 wt %) of Ludox silica nanoparticles with varying concentration of BSA (0�5 wt %) at pH7. Results show that silica nanoparticles and BSA coexist as individual entities at low concentration of BSA where electrostatic repulsive interactions between them prevent their aggregation. However, as the concentration of BSA increases (? 0.5 wt %), it induces the attractive depletion interaction among nanoparticles leading to finally their aggregation at higher BSA concentration (2 wt %). The aggregates are found to be governed by the diffusion limited aggregation (DLA) morphology of fractal nature having fractal dimension about 2.4.
Yadav, Indresh, E-mail: firstname.lastname@example.com; Aswal, V. K., E-mail: firstname.lastname@example.com [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai-400085 (India); Kohlbrecher, J. [Laboratory for Neutron Scattering, Paul Scherrer Institute, CH-5232 PSI Villigen Switzerland (Switzerland)
Ultracold Molecules from Ultracold Atoms: Interactions in Sodium and Lithium Gas
Ultracold Molecules from Ultracold Atoms: Interactions in Sodium and Lithium Gas by Caleb from Ultracold Atoms: Interactions in Sodium and Lithium Gas by Caleb A Christensen Submitted of Philosophy Abstract The thesis presents results from experiments in which ultracold Sodium-6 and Lithium-23
A comparison of mechanical properties and scaling law relationships for silica aerogels and their organic counterparts
Aerogels are a special class of open-cell foams derived from the supercritical extraction of highly crosslinked, inorganic or organic gels. The resultant materials have ultrafine cell/pore sizes (< 100 nm), high surface areas (350--1000m{sup 2}/g), and a microstructure composed of interconnected colloidal-like particles or polymeric chains with characteristic diameters of 10 nm. TEM and SAXS show that this microstructure is sensitive to variations in processing conditions that influence crosslinking chemistry and growth processes prior to gelation. Traditional silica aerogels are prepared via the hydrolysis and condensation of tetramethoxy silane (TMOS) or tetraethoxy silane (TEOS). Factors such as pH and the (H{sub 2}O)/(TMOS) ratio affect the microstructure of the dried aerogel. It is generally accepted that polymeric' silica aerogels result from acid catalysis while colloidal'silica aerogels result from base catalysis. Recently, Hrubesh and Tillotson developed a new condensed silica' procedure for obtaining silica aerogels with densities as low as 0.004g/cc, i.e. only 3{times} the density of air. Organic aerogels are formed from the aqueous, polycondensation of (1) resorcinol/formaldehyde or (2) melamine/formaldehyde. The microstructure of the resorcinol-formaldehyde (RF) aerogels is dictated by the amount of base catalyst used in the sol-gel polymerization. In addition, these materials can be pyrolyzed in an inert atmosphere to form vitreous carbon aerogels. Melamine- formaldehyde (MF) aerogels that are both colorless and transparent are only formed under acidic conditions (i.e. pH = 1--2). In this paper, the microstructural dependence and scaling law relationships for the compressive modulus of silica, carbon, RF, and MF aerogels will be discussed in detail. 17 refs., 1 fig.
Pekala, R.W.; Hrubesh, L.W.; Tillotson, T.M.; Alviso, C.T.; Poco, J.F.; LeMay, J.D.
Development of 3-D magnetic nano-arrays by electrodeposition into mesoporous silica.
The development of periodic nanostructures fabricated by self-assembly of surfactants and block co-polymers has opened up the possibility of generating periodic magnetic nanostructures of types not accessible by self-assembly of nano-particles. The fabrication of mesoporous silica thin films around self-assembled block co-polymers is well established. Common structures for such films are SBA-15 which consists of hexagonal arrays of cylindrical pores and SBA-16 which has face centered arrays of spherical voids. These pores are connected by 1-2 nm thick flaws in the continuous silica phase producing an effectively continuous porous phase. After removal of the block co-polymer template, electrodeposition into the mesoporous silica thin films produces arrays of 5-10 nm diameter nano-wires and nano-particles. We have demonstrated that such materials can be fabricated on a wide range of metal substrates. Characterization by Scanning Electron Microscopies shows that the mesoporous silica is well ordered over micron scale areas. Grazing Incidence Small Angle X-ray Scattering (GISAXS) studies shows diffraction spots, consistent with the entire film being well ordered. GISAXS also shows that the mesoporous silica films survive removal of the template and electrodeposition of nickel and cobalt into the mesoporous silica films. Such films are of interest for their magnetic properties, as the nanophase and scale can be independently varied. Further, the presence of nanowires inside an insulator suggests that these films might also be of interest as the current confining element for Confined Current Path-Current Perpendicular to Plane GMR sensors.
Campbell, R.; Manning, J.; Bakker, M.G.; Li, X.; Lee, D.R.; Wang, J.; X-Ray Science Division; Univ. of Alabama
Very large-scale structures in sintered silica aerogels as evidenced by atomic force microscopy and ultra-small angle
Very large-scale structures in sintered silica aerogels as evidenced by atomic force microscopy of silica aerogels has been extensively studied mainly by scattering techniques (neutrons, X-rays, light) and atomic force microscopy (AFM) experiments have been carried out on aerogels at dierent steps of densi
Demouchy, Sylvie
Ultra-large bandwidth hollow-core guiding in all-silica Bragg fibers with nano-supports
Ultra-large bandwidth hollow-core guiding in all-silica Bragg fibers with nano-supports Guillaume 420, 650-653 (2002). 7. C. M. Smith et al., "Low-loss hollow-core silica/air photonic bandgap fibre firstname.lastname@example.com. Abstract: We demonstrate a new class of hollow-core Bragg fibers
Huang, Yanyi
Am J Epidemiol . Author manuscript Aluminum and silica in drinking water and the risk of Alzheimers disease'
Am J Epidemiol . Author manuscript Page /1 10 Aluminum and silica in drinking water and the risk associations between exposure to aluminum or silica from drinking water and risk of cognitive decline, dementia of dementia, aged' 65 years and over living in 91 civil drinking water areas in Southern France. Two measures
Structure and Dynamics of Acetonitrile Confined in a Silica Nanopore Liwen Cheng, Joseph A. Morrone, and B. J. Berne*
Structure and Dynamics of Acetonitrile Confined in a Silica Nanopore Liwen Cheng, Joseph A. Morrone York 10027, United States ABSTRACT: Acetonitrile confined in silica nanopores with surfaces of varying. It is found that acetonitrile orders into bilayer like structures near the surface, in agreement with prior
Berne, Bruce J.
Water, chloroform, acetonitrile, and atrazine adsorption to the amorphous silica surface studied by vibrational sum frequency generation spectroscopy
Water, chloroform, acetonitrile, and atrazine adsorption to the amorphous silica surface studied the airsilica interface before, during, and after adsorption of water, chloroform, acetonitrile the compounds. Adsorption of chloro- form and acetonitrile was weaker compared to water. Binding to the surface
IMPROVING SILICA FUME FOR CONCRETE BY SURFACE TREATMENT X. Li and D.D.L. Chung1
(Type I) from Lafarge Corp. (Southfield, MI). The silica fume (Elkem Materials, Inc., Pittsburgh, PA, EMS 965) was used in the amount of 15% by weight of cement. Surface treatment of silica fume Printed in the USA. All rights reserved 0008-8846/98 $19.00 .00 PII S0008-8846(98)00017-9 493 #12;effect
Chung, Deborah D.L.
Applications of Geothermally-Produced Colloidal Silica in Reservoir Management - Smart Gels
In enhanced geothermal systems (EGS) the reservoir permeability is often enhanced or created using hydraulic fracturing. In hydraulic fracturing, high fluid pressures are applied to confined zones in the subsurface usually using packers to fracture the host rock. This enhances rock permeability and therefore conductive heat transfer to the circulating geothermal fluid (e.g. water or supercritical carbon dioxide). The ultimate goal is to increase or improve the thermal energy production from the subsurface by either optimal designs of injection and production wells or by altering the fracture permeability to create different zones of circulation that can be exploited in geothermal heat extraction. Moreover, hydraulic fracturing can lead to the creation of undesirable short-circuits or fast flow-paths between the injection and extraction wells leading to a short thermal residence time, low heat recovery, and thus a short-life of the EGS. A potential remedy to these problems is to deploy a cementing (blocking, diverting) agent to minimize short-cuts and/or create new circulation cells for heat extraction. A potential diverting agent is the colloidal silica by-product that can be co-produced from geothermal fluids. Silica gels are abundant in various surface and subsurface applications, yet they have not been evaluated for EGS applications. In this study we are investigating the benefits of silica gel deployment on thermal response of an EGS, either by blocking short-circuiting undesirable pathways as a result of diverting the geofluid to other fractures; or creating, within fractures, new circulation cells for harvesting heat through newly active surface area contact. A significant advantage of colloidal silica is that it can be co-produced from geothermal fluids using an inexpensive membrane-based separation technology that was developed previously using DOE-GTP funding. This co-produced silica has properties that potentially make it useful as a fluid diversion agent for subsurface applications. Colloidal silica solutions exist as low-viscosity fluids during their �induction period� but then undergo a rapid increase in viscosity (gelation) to form a solid gel. The length of the induction period can be manipulated by varying the properties of the solution, such as silica concentration and colloid size. We believe it is possible to produce colloidal silica gels suitable for use as diverting agents for blocking undesirable fast-paths which result in short-circuiting the EGS once hydraulic fracturing has been deployed. In addition, the gels could be used in conventional geothermal fields to increase overall energy recovery by modifying flow.
Hunt, Jonathan
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Preparation of Mesoporous Silica Templated Metal Nanowire Films on Foamed Nickel Substrates
A method has been developed for the formation of high surface area nanowire films on planar and three-dimensional metal electrodes. These nanowire films are formed via electrodeposition into a mesoporous silica film. The mesoporous silica films are formed by a sol-gel process using Pluronic tri-block copolymers to template mesopore formation on both planar and three-dimensional metal electrodes. Surface area increases of up to 120-fold have been observed in electrodes containing a templated film when compared to the same types of electrodes without the templated film.
Campbell, Roger [University of Alabama, Tuscaloosa; Kenik, Edward A [ORNL; Bakker, Martin [University of Alabama, Tuscaloosa; Havrilla, George [Los Alamos National Laboratory (LANL); Montoya, Velma [Los Alamos National Laboratory (LANL); Shamsuzzoha, Mohammed [University of Alabama, Tuscaloosa
Method and composition in which metal hydride particles are embedded in a silica network
A silica embedded metal hydride composition and a method for making such a composition. The composition is made via the following process: A quantity of fumed silica is blended with water to make a paste. After adding metal hydride particles, the paste is dried to form a solid. According to one embodiment of the invention, the solid is ground into granules for use of the product in hydrogen storage. Alternatively, the paste can be molded into plates or cylinders and then dried for use of the product as a hydrogen filter. Where mechanical strength is required, the paste can be impregnated in a porous substrate or wire network.
Heung, Leung K. (Aiken, SC)
Decomposition of cumyl hydroperoxide in the presence of sulphonated silica in a flow-type system
An investigation has been made of the decomposition of cumyl hydroperoxide (CHP) in the presence of silica-based sulphocationites in a flow-type system. It was established that the given specimens are effective catalysts for the decomposition of CHP into phenol and acetone. It was shown that, in the course of the process, no irreversible poisoning of the surface of the catalyst by the products of CHP decomposition occurs. Data of chromatographic analysis of the products of CHP decomposition in the presence of sulphuric acid and silica-based sulphocationites are given.
Shelpakova, N.A.; Ioffa, A.F.
Bulk and surface laser damage of silica by picosecond and nanosecond pulses at 1064 nm
We measured bulk and surface dielectric breakdown thresholds of pure silica for 14 ps and 8 ns pulses of 1064 nm light. The thresholds are sharp and reproducible. For the 8 ns pulses the bulk threshold irradiance is 4.75 {+-} 0.25 kW/{mu}m{sup 2}. The threshold is approximately three times higher for 14 ps pulses. For 8 ns pulses the input surface damage threshold can be made equal to the bulk threshold by applying an alumina or silica surface polish.
Smith, Arlee V.; Do, Binh T
Effect of Carbon Black and Silica Fillers in Elastomer Blends Yimin Zhang, S. Ge, B. Tang, T. Koga, M. H. Rafailovich,*, J. C. Sokolov,
, the effect of carbon black is offset by silica fillers. Introduction Fillers exist in a variety of systemsEffect of Carbon Black and Silica Fillers in Elastomer Blends Yimin Zhang, S. Ge, B. Tang, T. Koga January 30, 2001 ABSTRACT: The effects of carbon black and pyrogeneous silica fillers on the interfacial
Ion irradiation damage in k-doped silica probed by the Er3+ luminescence lifetime at 1.535 pm4
irradiation.' Furthermore, silica-basedop- tical fibers are the standard in telecommunicationtechnol- ogy the effectof MeV ion irradiation damage on the optical propertiesof Er-doped silica films is studied. Erbium-doped silica glasshas recently attracted attention becauseof its use in optical fiber amplifiers.5'6Erbium
Polman, Albert
Clinch River breeder reactor sodium fire protection system design and development
To assure the protection of the public and plant equipment, improbable accidents were hypothesized to form the basis for the design of safety systems. One such accident is the postulated failure of the Intermediate Heat Transfer System (IHTS) piping within the Steam Generator Building (SGB), resulting in a large-scale sodium fire. This paper discusses the design and development of plant features to reduce the consequences of the accident to acceptable levels. Additional design solutions were made to mitigate the sodium spray contribution to the accident scenario. Sodium spill tests demonstrated that large sodium leaks can be safely controlled in a sodium-cooled nuclear power plant.
Foster, K.W.; Boasso, C.J.; Kaushal, N.N.
Selective Adsorption of Sodium Aluminum Fluoride Salts from Molten Aluminum
Aluminum is produced in electrolytic reduction cells where alumina feedstock is dissolved in molten cryolite (sodium aluminum fluoride) along with aluminum and calcium fluorides. The dissolved alumina is then reduced by electrolysis and the molten aluminum separates to the bottom of the cell. The reduction cell is periodically tapped to remove the molten aluminum. During the tapping process, some of the molten electrolyte (commonly referred as �bath� in the aluminum industry) is carried over with the molten aluminum and into the transfer crucible. The carryover of molten bath into the holding furnace can create significant operational problems in aluminum cast houses. Bath carryover can result in several problems. The most troublesome problem is sodium and calcium pickup in magnesium-bearing alloys. Magnesium alloying additions can result in Mg-Na and Mg-Ca exchange reactions with the molten bath, which results in the undesirable pickup of elemental sodium and calcium. This final report presents the findings of a project to evaluate removal of molten bath using a new and novel micro-porous filter media. The theory of selective adsorption or removal is based on interfacial surface energy differences of molten aluminum and bath on the micro-porous filter structure. This report describes the theory of the selective adsorption-filtration process, the development of suitable micro-porous filter media, and the operational results obtained with a micro-porous bed filtration system. The micro-porous filter media was found to very effectively remove molten sodium aluminum fluoride bath by the selective adsorption-filtration mechanism.
Leonard S. Aubrey; Christine A. Boyle; Eddie M. Williams; David H. DeYoung; Dawid D. Smith; Feng Chi
Cleaning Cesium Radionuclides from BN-350 Primary Sodium
This paper reports the successful design and operation of a system to remove highly radioactive cesium from the sodium coolant of the BN-350 reactor in Aktau, Kazakhstan. As an international effort between the United States and the Republic of Kazakhstan, a cesium-trapping system was jointly designed, fabricated, installed, and successfully operated. The results are significant for a number of reasons, including (a) a significant reduction of radioactivity levels of the BN-350 coolant and reactor surfaces, thereby reducing exposure to workers during shutdown operations; (b) demonstration of scientific ideas; and (c) the engineering application of effective cesium trap deployment for commercial-sized liquid-metal reactors. About 255 300 GBq (6900 Ci) of cesium was trapped, and the {sup 137}Cs specific activity in BN-350 primary sodium was decreased from 296 MBq/kg (8000 {mu}Ci/kg) to 0.37 MBq/kg (10 {mu}Ci/kg) by using seven cesium traps containing reticulated vitreous carbon (RVC) as the cesium adsorbent. Cesium trapping was accomplished by pumping sodium from the primary circuit, passing it through a block of RVC within each trap, and returning the cleaned sodium to the primary circuit. Both to predict and to analyze the behavior of the cesium traps in the BN-350 reactor primary circuit, a model was developed that satisfactorily describes the observed results of the cesium trapping. By using this model, thermodynamic parameters, such as the heat of adsorption of cesium atoms on RVC and on internal piping surfaces of the BN-350 reactor primary circuit, -22.7 and -5.0 kJ/mole, respectively, were extracted from the experimental data.
Romanenko, O.G.; Allen, K.J.; Wachs, D.M.; Planchon, H.P.; Wells, P.B.; Michelbacher, J.A.; Nazarenko, P.; Dumchev, I.; Maev, V.; Zemtzev, B.; Tikhomirov, L.; Yakovlev, V.; Synkov, A
Sodium boiling dryout correlation for LMFBR fuel assemblies
Under certain postulated accident conditions for a Liquid Metal Fast Breeder Reactor (LMFBR), such as the failure of the shutdown heat removal system (SHRS), sodium boiling and clad dryout might occur in the fuel assemblies. It is important to predict the time from boiling inception to dryout, since sustained clad dryout will result in core damage. In this paper a dryout correlation is presented. This correlation is based on 21 boiling tests which resulted in dryout from the THORS BUNDLE 6A, a 19-pin full-length simulated LMFBR fuel assembly and from the THORS Bundle 9, a 61-pin full-length simulated LMFBR fuel assembly. All these tests were performed as follows: for each specified bundle power, an initial steady-state high sodium flow was established, for which sodium boiling did not occur in the bundle. The temperature at the outlet of the test section was approx. 700/sup 0/C. Then, using a programmable pump control system, the flow was reduced to a low value and boiling occurred.
Carbajo, J.J.; Rose, S.D.
Sodium-Bearing Waste Treatment, Applied Technology Plan
Settlement Agreement between the Department of Energy and the State of Idaho mandates treatment of sodium-bearing waste at the Idaho Nuclear Technology and Engineering Center within the Idaho National Engineering and Environmental Laboratory. One of the requirements of the Settlement Agreement is to complete treatment of sodium-bearing waste by December 31, 2012. Applied technology activities are required to provide the data necessary to complete conceptual design of four identified alternative processes and to select the preferred alternative. To provide a technically defensible path forward for the selection of a treatment process and for the collection of needed data, an applied technology plan is required. This document presents that plan, identifying key elements of the decision process and the steps necessary to obtain the required data in support of both the decision and the conceptual design. The Sodium-Bearing Waste Treatment Applied Technology Plan has been prepared to provide a description/roadmap of the treatment alternative selection process. The plan details the results of risk analyzes and the resulting prioritized uncertainties. It presents a high-level flow diagram governing the technology decision process, as well as detailed roadmaps for each technology. The roadmaps describe the technical steps necessary in obtaining data to quantify and reduce the technical uncertainties associated with each alternative treatment process. This plan also describes the final products that will be delivered to the Department of Energy Idaho Operations Office in support of the office's selection of the final treatment technology.
Lance Lauerhass; Vince C. Maio; S. Kenneth Merrill; Arlin L. Olson; Keith J. Perry
Heavy metal phosphate nanophases in silica: influence of radiolysis probed via f-electron state properties
We have assessed the feasibility of carrying out time- and wavelength-resolved laser-induced fluorescence measurements of radiation damage in glassy silica. The consequences of alpha decay of Es-253 in LaPO{sub 4} nanophases embedded in silica were probed based on excitation of 5f states of Cm{sup 3+}, Bk{sup 3+}, and Es{sup 3+} ions. The recorded emission spectra and luminescence decays showed that alpha decay of Es-253 ejected Bk-249 decay daughter ions into the surrounding silica and created radiation damage within the LaPO{sub 4} nanophases. This conclusion is consistent with predictions of an ion transport code commonly used to model ion implantation. Luminescence from the {sup 6}D{sub 7/2} state of Cm{sup 3+}was used as an internal standard. Ion-ion energy transfer dominated the dynamics of the observed emitting 5f states and strongly influenced the intensity of observed spectra. In appropriate sample materials, laser-induced fluorescence provides a powerful method for fundamental investigation of alpha-induced radiation damage in silica.
Beitz, James V. [Chemistry Division, 9700 South Cass Avenue, Argonne National Laboratory, Argonne, IL 60439-4831 (United States)]. E-mail: firstname.lastname@example.com; Williams, C.W. [Chemistry Division, 9700 South Cass Avenue, Argonne National Laboratory, Argonne, IL 60439-4831 (United States); Hong, K.-S. [Chemistry Division, 9700 South Cass Avenue, Argonne National Laboratory, Argonne, IL 60439-4831 (United States); Liu, G.K. [Chemistry Division, 9700 South Cass Avenue, Argonne National Laboratory, Argonne, IL 60439-4831 (United States)
Fluorescent silica colloids for study and visualization of skin care products
due to long exposures to cold and dry air (7). Different skin care products are used to hy- drate dryFluorescent silica colloids for study and visualization of skin care products Swaminathan Iyer: The efficacy of skin care products depends on the time and dynamics of their absorbance by the skin, and its
Sokolov, Igor
Effects of Surface Modification Conditions on Hydrophobicity of Silica-based Coating Additives
Superhydrophobic silica (SHS) powders are being evaluated as a potential additive to the polyurethane topcoats used in Chemical Agent Resistant Coating (CARC) systems, with the goal of improving water repellency and corrosion protection characteristics. The current generation of CARC topcoats is already highly loaded with solids, and thus there is a premium on minimization of the total SHS powder required to achieve the desired properties. Therefore, efficient surface modification of the silica and proper dispersion in the coating will be required. The effect of a dispersant on the surface modification of silica particles by chlorosilanes was addressed in this study. The properties of various SHS powders were characterized by thermogravimetric analysis and mass spectroscopy. Correlations between powder modification conditions and the ultimate effects of the modified particles on hydrophobicity of CARC topcoats were assessed. The use of contact and rolling angle measurements along with scanning electron microscopy are discussed as they pertain to the ability to quantify the effects of modified silicas on corrosion prevention coatings. Furthermore, a systematic approach to modifying and testing both powders and top coats of corrosion prevention systems is presented.
Armstrong, Beth L [ORNL] [ORNL; Pawel, Steven J [ORNL] [ORNL; Hunter, Scott Robert [ORNL] [ORNL; Haynes, James A [ORNL] [ORNL; Hillesheim, Daniel A [ORNL] [ORNL
A neutron scattering technique was developed to measure the density of heavy water confined in a nanoporous silica matrix in a temperature-pressure range, from 300 to 130 K and from 1 to 2,900 bars, where bulk water will ...
Faraone, Antonio
Effectiveness of cabs for dust and silica control on mobile mining equipment
The Mine Safety and Health Administration (MSHA) has conducted a study to evaluate the effectiveness of cabs for controlling silica dust exposure during operation of mobile mining equipment. This study focused on bulldozers, front-end loaders and haul trucks, was conducted at surface coal mining operations and underground metal and nonmetal mining operations. Each piece of equipment tested was equipped with a cab. The vehicles sampled were from a range of manufacturers having different types of filter media and air intake configurations. The purpose of this study was to determine the reduction of dust and silica exposure that could be achieved through the use of a well-maintained cab. For each piece of equipment, dust and silica concentrations inside and outside the cab were determined and compared. In some cases, filtration efficiencies could be calculated. A properly designed environmental cab is sealed, has an intake air filtration system, and a heating and cooling system. Cabs should have good seals around the doors and windows. Factors such as cab pressurization filtration systems, filter media, and maintenance practices were also examined. In some cases, dust and silica reduction of 90 to 95% were observed.
Garcia, J.J.; Gresh, R.E.; Gareis, M.B.; Haney, R.A.
Silica Supported Single-Walled Carbon Nanotubes as a Modifier in Polyethylene Composites
Silica Supported Single-Walled Carbon Nanotubes as a Modifier in Polyethylene Composites Neal D. Mc.interscience.wiley.com). ABSTRACT: Composites have been made from single- wall carbon nanotubes in a polyethylene (PE) matrix: additives; composites; conducting polymers; nanocomposites; polyethylene INTRODUCTION Polyethylene (PE
Resasco, Daniel
E-Print Network 3.0 - amorphous silica dissolution Sample Search...
Microscopic Surface Processes Across Summary: No electrolytes 0.1 -2.3 670 0.0167 M CaCl2 0.65 -0.4 44 0.0167 M CaCl2 0.1 -2.3 4 12;DISSOLUTION OF SILICA... Kinetics of...
TESLA-FEL 2004-01 Silica Aerogel Radiators for Bunch Length
TESLA-FEL 2004-01 Silica Aerogel Radiators for Bunch Length Measurements J. B¨ahr a , V. Djordjadze aerogel are used to measure the electron bunch length at the photo injector test facility at DESY Zeuthen by the usage of aerogel is calculated analytically and Monte Carlo simulations are performed. It is shown
Acidity and catalytic activity of zeolite catalysts bound with silica and alumina
. Micropore surface area and micropore volume are reduced by about 19% and 18%, respectively, indicating some micropores of ZSM-5 are blocked on binding with silica. SiO2-bound ZSM-5 catalysts have less catalytic activity for butane transformation (cracking...
Wu, Xianchun
Characterization of the intrinsic strength between epoxy and silica using a multiscale approach
, we report a model to predict the intrinsic strength between organic and inorganic materials, based energy surface between attached and detached states of the bonded system and scaled up to incorporate readily in many other polymers. Silica, commonly found material in nature in the form of sand or quartz
1 MODELING THE MEAN INTERACTION FORCES BETWEEN POWDER PARTICLES. APPLICATION TO SILICA GEL-MAGNESIUM) particles (d50 = 55 µm) were coated with fine invited particles of magnesium stearate (MS, d50 = 4.6 µm. Interaction forces between the material attached to the cantilever (Magnesium Stearate MS) and the surface
Fluorocarbon plasma etching and profile evolution of porous low-dielectric-constant silica
of PS, a feature profile model has been integrated with a plasma equipment model. To focus on issuesFluorocarbon plasma etching and profile evolution of porous low-dielectric-constant silica Arvind silicon dioxide PS is one such material. To address scaling issues during fluorocarbon plasma etching
Kushner, Mark
Plasticity-induced structural anisotropy of silica glass C. L. Rountree1
Plasticity-induced structural anisotropy of silica glass C. L. Rountree1 , D. Vandembroucq2 , M anisotropic structure after extended shear plastic flow. This anisotropy which survives for an un- stressed tetrahedra microstructure remains mostly unaltered. PACS numbers: 62.20.F, 81.05.Kf Plasticity of amorphous
EPR study of the adsorption of dioxin vapours onto microporous carbons and mesoporous silica
EPR study of the adsorption of dioxin vapours onto microporous carbons and mesoporous silica M 31 October 2010 Keywords: EPR AC MTS Surface characterization Dioxin a b s t r a c t Computer aided with a nitroxide radical (TCDD-T) was employed to investigate the adsorption of dioxin vapours onto two carbons
Turro, Nicholas J.
. The silica fume (Elkem Materials, Inc., Pittsburgh, PA, EMS 965) was used in the amount of 15% by weight 14260-4400, USA (Received February 6, 1998; in final form June 26, 1998) ABSTRACT The addition of sand. 10, pp. 13531356, 1998 Copyright © 1998 Elsevier Science Ltd Printed in the USA. All rights reserved
The fatigue of high-strength fused silica optical fibers in low humidity q
the effect of humidity on the kinetics of subcritical crack growth in high strength optical fibers that the rate of subcritical crack growth is given by dc dt ¼ A exp n KI KIC ; ð1�? where A and n are fatigue by assuming a simple chemical kinetics model for fatigue in which the reaction rate between water and silica
Activation energy and entropy of dynamic fatigue of pristine silica optical fibers
, NJ 08 854-8065 ABSTRACT Subcritical crack growth in fused silica can be modeled as a stress assisted chemical reaction between water and strained bonds at the crack tip. The stress influences the crack growth which has been most commonly used for brittle ceramic materials is the well-known subcritical crack
of stress, temperature and activity of the corroding species (e.g. water). A power law degradation kinetics the degradation depends on the applied stress. Subcritical Crack Growth Model The reliability of silica optical fiber under stress is usually described by the subcritical crack growth model. It is assumed
Materials are being developed in U.S. for the removal and immobilization of iodine from gaseous products of nuclear fuel reprocessing in support of the Fuel Cycle Technology Separations and Waste Forms Campaign. The silver-functionalized silica aerogel proved to be an excellent candidate for this treatment because of its high selectivity and sorption capacity for radioiodine and its possible conversion to a durable silica-based waste form. The present study investigated with nitrogen sorption and helium pycnometry the effect of pressureless isothermal sintering at temperatures of 900-1400�C for 2.5-90 min or isothermal hot-pressing at 1200�C for 2.5 min on densification of raw and silver-functionalized silica aerogel granules. Rapid sintering was observed at 1050 and 1200�C. Only 15 min of pressureless sintering at 1200�C resulted in almost complete densification. The macropores disappeared, surface area decreased from 1114 m2/g to 25 m2/g, pore volume from 7.41 cm3/g to 0.09 cm3/g, and adsorption pore size from 18.7 to 7 nm. The skeletal density of sintered granules was similar to the bulk density of amorphous silica (2.2 g/cm3). The hot-pressing accelerated the sintering process, decreasing significantly the pore size and volume.
Matyas, Josef; Robinson, Matthew J.; Fryxell, Glen E.
Acoustic and Thermal Characterization of Oil Migration, Gas Hydrates Formation and Silica Diagenesis
Acoustic and Thermal Characterization of Oil Migration, Gas Hydrates Formation and Silica Rights Reserved #12;ABSTRACT Acoustic and Thermal Characterization of Oil Migration, Gas Hydrates-A to Opal-CT, the formation of gas hydrates, fluid substitution in hydrocarbon reservoirs, and fluid
Guerin, Gilles
Disposal of high-level nuclear waste is horrendously expensive, in large part because the actual radioactive matter in the tanks has been diluted over 1000-fold by ordinary inorganic chemicals. Treatment processes themselves can exacerbate the problem by adding further volume to the waste. Waste retrieval and sludge washing, for example, will require copious amounts of sodium hydroxide. If the needed sodium hydroxide could be separated from the waste and recycled, however, the addition of fresh sodium hydroxide could be avoided, ultimately reducing the final waste volume and associated disposal costs. The major objective of this research is to explore new liquid-liquid extraction approaches to the selective separation of sodium hydroxide from alkaline high-level wastes stored in underground tanks at the Hanford and Savannah River sites. Consideration is also given to separating potassium and abundant anions, including nitrate, nitrite, aluminate, and carbonate. Salts of these ions represent possible additional value for recycle, alternative disposal, or even use as commodity chemicals. A comprehensive approach toward understanding the extractive chemistry of these salts is envisioned, involving systems of varying complexity, from use of simple solvents to new bifunctional host molecules for ion-pair recognition. These extractants will ideally require no adjustment of the waste composition and will release the extracted salt into water, thereby consuming no additional chemicals and producing no additional waste volume. The overall goal of this research is to provide a scientific foundation upon which the feasibility of new liquid-liquid extraction chemistry applicable to the bulk reduction of the volume of tank waste can be evaluated.
Moyer, Bruce A.; Marchand, Alan P.
Disposal of high- level waste is horrendously expensive, in large part because the actual radioactive matter in the tanks has been diluted over 1000-fold by ordinary inorganic chemicals. Treatment processes themselves can exacerbate the problem by adding further volume to the waste. Waste retrieval and sludge washing, for example, will require copious amounts of sodium hydroxide. If the needed sodium hydroxide could be separated from the waste and recycled, however, the addition of fresh sodium hydroxide could be avoided, ultimately reducing the final waste volume and associated disposal costs. The major objective of this research is to explore new liquid- liquid extraction approaches to the selective separation of sodium hydroxide from alkaline high-level wastes stored in underground tanks at the Hanford and Savannah River sites. Consideration is also given to separating potassium and abundant anions, including nitrate, nitrite, aluminate, and carbonate. Salts of these ions represent possible additional value for recycle, alternative disposal, or even use as commodity chemicals. A comprehensive approach toward understanding the extractive chemistry of these salts is envisioned, involving systems of varying complexity, from use of simple solvents to new bifunctional host molecules for ion-pair recognition. These extractants will ideally require no adjustment of the waste composition and will release the extracted salt into water, thereby consuming no additional chemicals and producing no additional waste volume. The overall goal of this research is to provide a scientific foundation upon which the feasibility of new liquid-liquid extraction chemistry applicable to the bulk reduction of the volume of tank waste can be evaluated.
Determination of silica scale deposition rates and thresholds applied toward protection of injection reservoirs. Quarterly progress report, July 1--September 30, 1998
The program objective aims to identify the highest temperature at which silica scale will develop from partially evaporated and significantly cooled geothermal liquid. The approach involves tracking deposition of silica scale by monitoring the apparent electrical conductivity of the geothermal liquid in an isolation chamber. A decrease in apparent conductivity occurs because silica deposited on electrode surfaces is less conductive than the geothermal liquid. The major technical hurdle is building a conductivity monitoring system that is sensitive enough to distinguish between no silica deposition and almost no silica deposition, while accounting for other factors which also affect conductivity, such as temperature and varying fluid composition.
Silica Supported Ceria Nanoparticles: A Hybrid Nanostructure To Increase Stability And Surface Reactivity Of Nano-crystalline Ceria
The mixed oxidation state (3+/4+) of ceria nanoparticles of smaller sizes make them attractive materials for their catalytic antioxidant biological properties. However the unmodified smaller ceria nanoparticles are limited in their use due to particles agglomeration and reduced surface chemical reactivity in the solutions used to disperse the nanoparticles. This work describes an effort to stabilize small ceria nanoparticles, retaining their desired activity, on a larger stable silica support. The ceria nanoparticles attached to silica was synthesized by a solution synthesis technique in which the surface functional groups of silica nanoparticles were found to be essential for the formation of smaller ceria nanoparticles. The surface chemical and vibrational spectroscopy analysis revealed cerium�silicate (Ce-O-Si) covalent bond linkage between silica and cerium oxide nanoparticles. The colloidal properties (agglomerate particle size and suspension stability) of ceria attached to silica was significantly improved due to inherent physico-chemical characteristics of silica against random collision and gravitation settling as opposed to unmodified ceria nanoparticles in solution. The bio-catalytic activity of ceria nanoparticles in the 3+ oxidation state was not found to be limited by attachment to the silica support as measured by free radical scavenging activity in different biological media conditions.
Munusamy, Prabhakaran; Sanghavi, Shail P.; Varga, Tamas; Thevuthasan, Suntharampillai
Practical features of illumination with high pressure sodium lamps
A number of concerns raised about the health effects of high pressure sodium lamps (HPS) are discussed. The notion of a ''natural'' human photic environment based on sunlight is disputed. Humans are better adapted to the ''greenish'' spectral composition of forest light than to direct sunlight. It is ironic that the artificial light source which has received the most disapproval, cool white flourescent lamp, has a spectral composition similar to that of forest light. HPS is also available in a full range of colors. Some successful examples of HPS--from North Division High School, in Milwaukee, Wisconsin, to museum exhibits at National Geographic in Washington--are listed.
Corth, R.
Dynamic stability experiments in sodium-heated steam generators. [LMFBR
Seventy-two dynamic stability tests were performed in the sodium-heated boiling-water test facility at Argonne National Laboratory. A full-scale LMFBR steam generator tube was employed as the test section operating over the water parameter ranges of 6.9 to 15.9 MPa pressure and 170 to 800 kg/m/sup 2/.s mass flux. The stability thresholds from the test compared well to the predictions of a modified version of a correlation equation recently published by other investigators. Typical experimental data and the modified correlation equation are presented.
France, D.M.; Roy, R.; Carlson, R.D.; Chiang, T.
Interaction Between Trace Metals, Sodium and Sorbents in Combustion.
The proposed research is directed at an understanding of how to exploit interactions between sodium, toxic metals and sorbents, in order to optimize sorbents injection procedures, which can be used to capture and transform these metals into environmentally benign forms. The research will use a 17kW downflow, laboratory combustor, to yield data that can be interpreted in terms of fundamental kinetic mechanisms. Metals to be considered are lead, cadmium, and arsenic. Sorbents will be kaolinite, bauxite, and limestone. The role of sulfur will also be determined.
Wendt, O.L.; Davis, S.
Nanofriction on Sodium Polystyrene Sulfonate Brushes in Water
We investigated the frictional properties of sodium polystyrene sulfonate (NaPSS) brushes in water by frictional force microscopy (FFM). Polyelectrolyte brushes were prepared on silicon wafers by the grafting-to method. The brushes considerably reduce the frictional force and coefficient of kinetic friction compared to hydrodynamic lubrication on a smooth Si wafer. Frictional force is independent of sliding speed, but is lower for lower degrees of NaPSS polymerization. Nanoindentation tests indicate that the polymer chains in a brush are stretched strongly away from the substrate. These results suggest that polymer chains point support the FFM probe tip in water and reduced contact area and friction.
Takuya Fujima; Eitaro Futakuchi; Fumihiro Kino
Sodium Ion Insertion in Hollow Carbon Nanowires for Battery Applications. |
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administrationcontroller systemsBiSite CulturalDepartment ofat Home |EMSL Sodium Ion Insertion
Biological Applications and Transmission Electron Microscopy Investigations of Mesoporous Silica Nanoparticles
The research presented and discussed within involves the development of novel biological applications of mesoporous silica nanoparticles (MSN) and an investigation of mesoporous material by transmission electron microscopy (TEM). Mesoporous silica nanoparticles organically functionalized shown to undergo endocytosis in cancer cells and drug release from the pores was controlled intracellularly and intercellularly. Transmission electron microscopy investigations demonstrated the variety of morphologies produced in this field of mesoporous silica nanomaterial synthesis. A series of room-temperature ionic liquid (RTIL) containing mesoporous silica nanoparticle (MSN) materials with various particle morphologies, including spheres, ellipsoids, rods, and tubes, were synthesized. By changing the RTIL template, the pore morphology was tuned from the MCM-41 type of hexagonal mesopores to rotational moire type of helical channels, and to wormhole-like porous structures. These materials were used as controlled release delivery nanodevices to deliver antibacterial ionic liquids against Escherichia coli K12. The involvement of a specific organosiloxane function group, covalently attached to the exterior of fluorescein doped mesoporous silica nanoparticles (FITC-MSN), on the degree and kinetics of endocytosis in cancer and plant cells was investigated. The kinetics of endocystosis of TEG coated FITC-MSN is significantly quicker than FITC-MSN as determined by flow cytometry experiments. The fluorescence confocal microscopy investigation showed the endocytosis of TEG coated-FITC MSN triethylene glycol grafted fluorescein doped MSN (TEG coated-FITC MSN) into both KeLa cells and Tobacco root protoplasts. Once the synthesis of a controlled-release delivery system based on MCM-41-type mesoporous silica nanorods capped by disulfide bonds with superparamagnetic iron oxide nanoparticles was completed. The material was characterized by general methods and the dosage and kinetics of the antioxidant dependent release was measured. Finally, the biological interaction of the material was determined along with TEM measurements. An electron investigation proved that the pore openings of the MSN were indeed blocked by the Fe{sub 3}O{sub 4} nanoparticles. The biological interaction investigation demonstrated Fe{sub 3}O{sub 4}-capped MSN endocytosis into HeLa cells. Not only does the material enter the cells through endocytosis, but it seems that fluorescein was released from the pores most probably caused by disulfide bond reducing molecules, antioxidants. In addition to endocytosis and release, the Fe{sub 3}O{sub 4}-capped MSN propelled the cells across a cuvette upon induction of a magnet force. Finally, an important aspect of materials characterization is transmission electron microscopy. A TEM investigation demonstrated that incorporating different functional groups during the synthesis (co-condensation) changed the particle and pore morphologies.
Brian G. Trewyn
Visible Light Absorption of Binuclear TiOCoII Charge-Transfer Unit Assembled in Mesoporous Silica
Ti-MCM-41 silica in acetonitrile solution affords binucleardirectly dissolved in acetonitrile (50 mL) in a Schlenk tubeupon dissolving CoCl 2 in acetonitrile is believed to be the
Han, Hongxian; Frei, Heinz
??Chemical storage of hydrogen involves release of hydrogen in a controlled manner from materials in which the hydrogen is covalently bound. Sodium borohydride and aminoborane� (more)
McLafferty, Jason
E-Print Network 3.0 - affecting sodium hypochlorite Sample Search...
Workshop Summary: equipment, vehicles Sodium hypochlorite (bleach) 200-500 ppm Nets, boots, clothing. Surfaces must be clean... hypochlorite solution.Note: Bleach is 5.25%...
E-Print Network 3.0 - alkaline sodium borohydride Sample Search...
Aardahl, PNNL) The most critical hurdle for the use of sodium ... Source: DOE Office of Energy Efficiency and Renewable Energy, Hydrogen, Fuel Cells and Infrastructure...
E-Print Network 3.0 - aluminum sodium chloride Sample Search...
agents Water Acetyl chloride, alkaline and alkaline... hypochlorite, all oxidizing agents Carbon tetrachloride Sodium ... Source: Hall, Sharon J. - School of Life Sciences, Arizona...
The role of effective stress on silica solubility and pressure solution: an experimental investigation in a flow-through system
THE ROLE OF EFFECTIVE STRESS ON SILICA SOLUBILITY AND PRESSURE SOLUTION: AN EXPERIMENTAL INVESTIGATION IN A FLOW-THROUGH SYSTEM A Thesis by BRIAN PATRICK ELIAS Submitted to the Office of Graduate Studies of Texas A&M University in partial... fulfillment of the requirements for the degree of MASTER OF SCIENCE May 1989 Major Subject: Geology THE ROLE OF EFFECTIVE STRESS ON SILICA SOLUBILITY AND PRES SURE SOLUTION: AN EXPERIMENTAL INVESTIGATION IN A FLOW-THROUGH SYSTEM A Thesis by BRIAN...
Elias, Brian Patrick
Plutonium oxide (PuO{sub 2}) calcined at >900 C resists dissolution in nitric acid (HNO{sub 3})-potassium fluoride (KF) solutions, a common method for their dissolution. The Savannah River National Laboratory (SRNL) has developed an alternate method for large samples of PuO{sub 2}-bearing materials using sodium peroxide (Na{sub 2}O{sub 2}) fusion as a pretreatment. The products of the reaction between Na{sub 2}O{sub 2} and PuO{sub 2} have been reported in the literature. As part of the SRNL development effort, additional data about the reaction between Na{sub 2}O{sub 2} and PuO{sub 2} were required. Also needed were data concerning the reaction of Na{sub 2}O{sub 2} with other components that may be present in the feed materials. Sodium peroxide was reacted with aluminum metal (Al), beryllium metal (Be), graphite, potassium chloride (KCl), magnesium chloride (MgCl{sub 2}), and calcium chloride (CaCl{sub 2}). The paper reports and discusses the reaction products of these and related compounds with Na{sub 2}O{sub 2}.
Pierce, R.; Missimer, D.; Crowder, M.
Sodium fast reactor safety and licensing research plan. Volume I.
This report proposes potential research priorities for the Department of Energy (DOE) with the intent of improving the licensability of the Sodium Fast Reactor (SFR). In support of this project, five panels were tasked with identifying potential safety-related gaps in available information, data, and models needed to support the licensing of a SFR. The areas examined were sodium technology, accident sequences and initiators, source term characterization, codes and methods, and fuels and materials. It is the intent of this report to utilize a structured and transparent process that incorporates feedback from all interested stakeholders to suggest future funding priorities for the SFR research and development. While numerous gaps were identified, two cross-cutting gaps related to knowledge preservation were agreed upon by all panels and should be addressed in the near future. The first gap is a need to re-evaluate the current procedures for removing the Applied Technology designation from old documents. The second cross-cutting gap is the need for a robust Knowledge Management and Preservation system in all SFR research areas. Closure of these and the other identified gaps will require both a reprioritization of funding within DOE as well as a re-evaluation of existing bureaucratic procedures within the DOE associated with Applied Technology and Knowledge Management.
Sofu, Tanju (Argonne National Laboratory, Argonne, IL); LaChance, Jeffrey L.; Bari, R. (Brokhaven National Laboratory Upton, NY); Wigeland, Roald (Idaho National Laboratory, Idaho Falls, ID); Denman, Matthew R.; Flanagan, George F. (Oak Ridge National Laboratory, Oak Ridge, TN)
Preliminary engineering design of sodium-cooled CANDLE core
The CANDLE burning process is characterized by the autonomous shifting of burning region with constant reactivity and constant spacial power distribution. Evaluations of such critical burning process by using widely used neutron diffusion and burning codes under some realistic engineering constraints are valuable to confirm the technical feasibility of the CANDLE concept and to put the idea into concrete core design. In the first part of this paper, it is discussed that whether the sustainable and stable CANDLE burning process can be reproduced even by using conventional core analysis tools such as SLAROM and CITATION-FBR. As a result, it is certainly possible to demonstrate it if the proper core configuration and initial fuel composition required as CANDLE core are applied to the analysis. In the latter part, an example of a concrete image of sodium cooled, metal fuel, 2000MWt rating CANDLE core has been presented by assuming an emerging inevitable technology of recladding. The core satisfies engineering design criteria including cladding temperature, pressure drop, linear heat rate, and cumulative damage fraction (CDF) of cladding, fast neutron fluence and sodium void reactivity which are defined in the Japanese FBR design project. It can be concluded that it is feasible to design CANDLE core by using conventional codes while satisfying some realistic engineering design constraints assuming that recladding at certain time interval is technically feasible.
Takaki, Naoyuki; Namekawa, Azuma; Yoda, Tomoyuki; Mizutani, Akihiko; Sekimoto, Hiroshi [Department of Nuclear Engineering, Tokai University, Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan); AISA, Fuchu, Ishioka, Ibaraki 315-0013 (Japan); Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo, 152-8550 (Japan)
TRUEX partitioning studies applied to ICPP sodium-bearing waste
The Idaho Chemical Processing Plant (ICPP), located in southeast Idaho at the USDOE Idaho National Engineering Laboratory, formerly reprocessed highly enriched spent nuclear fuel to recover fissionable uranium. The HLW raffinates from the combined PUREX/REDOX type uranium recovery process were converted to solid oxides (calcine) in a high temperature fluidized bed. Liquid effluents from the calcination process were combined with liquid sodium bearing waste (SBW) generated primarily in conjunction with decontamination activities. Due to the high sodium content in the SBW, this secondary waste stream is not directly amenable to solidification via calcination. Currently, approximately 1.5 millon gallons of liquid SBW are stored at the ICPP in large tanks. Several treatment options for the SBW are currently being considered, including the TRansUranic EXtraction (TRUEX) process developed by Horwitz and co-workers at Argonne National Laboratory (ANL), in preparation for the final disposition of SBW. Herein described are experimental results of radionuclide tracer studies with simulated SBW using the TRUEX process solvent.
Herbst, R.S.; Brewer, K.N.; Law, J.D.; Tranter, T.J.; Todd, T.A.
Selection of materials for sodium fast reactor steam generators
Sodium Fast Reactor (SFR) is considered in France as the most mature technology of the different Generation IV systems. In the short-term the designing work is focused on the identification of the potential tracks to demonstrate licensing capability, availability, in-service inspection capability and economical performance. In that frame materials selection for the major components, as the steam generator, is a particularly key point managed within a French Research and Development program launched by AREVA, CEA and EDF. The choice of the material for the steam generator is indeed complex because various aspects shall be considered like mechanical and thermal properties at high temperature, interaction with sodium on one side and water and steam on the other side, resistance to wastage, procurement, fabrication, weldability and ability for inspection and in-situ intervention. The following relevant options are evaluated: the modified 9Cr1Mo ferritic-martensitic grade and the Alloy 800 austenitic grade. The objective of this paper is to assess for both candidates their abilities to reach the current SFR needs regarding material design data, from AFCEN RCC-MRx Code in particular, compatibility with environments and manufacturability. (authors)
Dubiez-Le Goff, S.; Garnier, S.; Gelineau, O. [AREVA (France); Dalle, F. [Commissariat a l'energie atomique et aux energies alternatives - CEA (France); Blat-Yrieix, M.; Augem, J. M. [Electricite de France - EDF (France)
Infrared spectroscopic study of the adsorption of carbon monoxide on silica-supported copper oxide
Adsorption of carbon monoxide at room temperature (0.1 to 50 Torr) on silica-supported copper oxide was studied by infrared spectroscopy. Catalysts were prepared by deposition-precipitation or impregnation. After calcination two types of adsorbed CO were identified showing absorption bands at 2136 +- 3 and 2204 +- 1 cm/sup -1/, which are ascribed to CO adsorbed on copper(II) oxide and on isolated copper(II) ions in the silica surface, respectively. Reduction and reoxidation removed the band at 2204 cm/sup -1/ with all samples and raised the intensity of the 2136-cm/sup -1/ band with the precipitated catalysts but not with the impregnation catalyst. Evidence is brought forward that the isolated copper ions are mobilized during reduction and generate new copper (oxide) surface. The change in background transmission of the samples could be used to obtain further information about the interaction of O/sub 2/ and CO with copper oxide.
De Jong, K.P.; Geus, J.W.; Joziasse, J.
Lasing characteristics of Er/sup 3 +/-doped silica fibers from 1553 up to 1603 nm
The laser oscillations from 1553 up to 1603 nm have been demonstrated in Er/sup 3 +/-doped silica fibers with a doping rate of 2500 ppm. Wide changes in laser oscillation wavelengths are due to broad splitting of the upper sublevels in the /sup 4/I/sub 152/ manifold, caused by the random structure of the silica matrix. It has been shown that unpumped parts of the Er/sup 3 +/ ions in the end pumped fiber laser configuration play an important role in the wavelength changes of the laser oscillation. For an absorbed pump power of 320 mW at 514 nm, output power of 0.5 mW was obtained at 1603 nm.
Kimura, Y.; Nakazawa, M.
Gamma radiation-induced refractive index change in Ge- and N-doped silica
We measured the change of the refractive index over a wide wavelength range in Ge- and N-doped high purity (fiber optics grade) silica glasses subjected to gamma irradiation. The radiation-induced change of the refractive index tends to be greater in the infrared part of the spectrum compare to the values measured in the UV-visible part of the spectrum. By means of the Kramers-Kronig relations, we estimate that a weak broadening of the optical vibration band of the silica network adds to this effect. The paper also discusses the difference observed in the spectral behavior of the induced refractive index change for both types of doped glass.
Brichard, Benoit [SCK-CEN-Belgian Nuclear Research Center, Boeretang 200, 2400 Mol (Belgium); Butov, Oleg V.; Golant, Konstantin M. [Fiber Optics Research Center, Russian Academy of Sciences, Vavilov Street 38, 119991 Moscow (Russian Federation); Fernandez Fernandez, Alberto [Masterminds Ltd., rue du Temple 40, CH-2800 Delemont (Switzerland)
Study of a Threshold Cherenkov Counter Based on Silica Aerogels with Low Refractive Indices ?
To identify ? � and K � in the region of 1.0 ? 2.5 GeV/c, a threshold Cherenkov counter equipped with silica aerogels has been investigated. Silica aerogels with a low refractive index of 1.013 have been successfully produced using a new technique. By making use of these aerogels as radiators, we have constructed a Cherenkov counter and have checked its properties in a test beam. The obtained results have demonstrated that our aerogel was transparent enough to make up for loss of the Cherenkov photon yield due to a low refractive index. Various configurations for the photon collection system and some types of photomultipliers, such as the fine-mesh type, for a read out were also tested. From these studies, our design of a Cherenkov counter dedicated to ?/K separation up to a few GeV/c with an efficiency greater than 90 % was considered. 1
I. Adachi; T. Sumiyoshi; K. Hayashi; N. Iida; R. Enomoto; K. Tsukada; R. Suda; S. Matsumoto; K. Natori; M. Yokoyama; H. Yokogawa
High-Q silica zipper cavity for optical radiation pressure driven MOMS switch
We design a silica zipper cavity that has high optical and mechanical Q (quality factor) values and demonstrate numerically the feasibility of a radiation pressure driven micro opto-mechanical system (MOMS) directional switch. The silica zipper cavity has an optical Q of 4.0 � 10{sup 4} and an effective mode volume V{sub mode} of 0.67?{sup 3} when the gap between two cavities is 34 nm. The mechanical Q (Q{sub m}) is determined by thermo-elastic damping and is 2.0 � 10{sup 6} in a vacuum at room temperature. The opto-mechanical coupling rate g{sub OM} is as high as 100 GHz/nm, which allows us to move the directional cavity-waveguide system and switch 1550-nm light with 770-nm light by controlling the radiation pressure.
Tetsumoto, Tomohiro; Tanabe, Takasumi, E-mail: firstname.lastname@example.com [Department of Electronics and Electrical Engineering, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi Kohoku, Yokohama 223-8522 (Japan)
Magnetic properties of mesoporous cobalt-silica-alumina ternary mixed oxides
Mesoporous cobalt-silica-alumina mixed oxides with variable cobalt content have been synthesized through slow evaporation method by using Pluronic F127 non-ionic surfactant as template. N{sub 2} sorption analysis of the template-free mixed oxide samples revealed that these mesoporous materials have high BET surface areas together with large mesopores. Powder XRD, TEM, EDS, FT IR and EPR spectroscopic analysis have been employed to understand the nature of the mesophases, bonding and composition of the materials. Low temperature magnetic measurements of these mixed oxide materials show the presence of ferromagnetic correlation at elevated temperature though at low temperature paramagnetic to ferrimagnetic transition is observed. Highlights: Black-Right-Pointing-Pointer Mesoporous cobalt-silica-alumina ternary mixed oxides. Black-Right-Pointing-Pointer High surface area and mesoporosity in magnetic materials. Black-Right-Pointing-Pointer Ferromagnetic correlation at elevated temperature. Black-Right-Pointing-Pointer Low temperature paramagnetic to ferrimagnetic transition.
Pal, Nabanita [Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032 (India)] [Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032 (India); Seikh, Md. Motin [Department of Chemistry, Visva-Bharati University, Santiniketan, West Bengal (India)] [Department of Chemistry, Visva-Bharati University, Santiniketan, West Bengal (India); Bhaumik, Asim, E-mail: firstname.lastname@example.com [Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032 (India)] [Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032 (India)
Laser-driven formation of a high-pressure phase in amorphous silica
A combination of electron diffraction and infrared reflectance measurements shows that synthetic silica transforms partially into stishovite under high-intensity (GW/cm2) laser irradiation, probably by the formation of a dense ionized plasma above the silica surface. During the transformation the silicon coordination changes from four-fold to six-fold and the silicon-oxygen bond changes from mostly covalent to mostly ionic, such that optical properties of the transformed material differ significantly from those of the original glass. This phase transformation offers one suitable mechanism by which laser-induced damage grows catastrophically once initiated, thereby dramatically shortening the service lifetime of optics used for high-power photonics applications such as inertial confinement fusion.
Salleo, Alberto; Taylor, Seth T.; Martin, Michael C.; Panero, Wendy R.; Jeanloz, Raymond; Genin, Francois Y.; Sands, Timothy
Experimental stress�strain analysis of tapered silica optical fibers with nanofiber waist
We experimentally determine tensile force�elongation diagrams of tapered optical fibers with a nanofiber waist. The tapered optical fibers are produced from standard silica optical fibers using a heat and pull process. Both, the force�elongation data and scanning electron microscope images of the rupture points indicate a brittle material. Despite the small waist radii of only a few hundred nanometers, our experimental data can be fully explained by a nonlinear stress�strain model that relies on material properties of macroscopic silica optical fibers. This is an important asset when it comes to designing miniaturized optical elements as one can rely on the well-founded material characteristics of standard optical fibers. Based on this understanding, we demonstrate a simple and non-destructive technique that allows us to determine the waist radius of the tapered optical fiber. We find excellent agreement with independent scanning electron microscope measurements of the waist radius.
Holleis, S.; Hoinkes, T.; Wuttke, C.; Schneeweiss, P.; Rauschenbeutel, A. [Vienna Center for Quantum Science and Technology, TU Wien�Atominstitut, Stadionallee 2, 1020 Vienna (Austria)
Molecular-dynamics simulations of thin polyisoprene films confined between amorphous silica substrates
Constant temperature�constant pressure (NpT) molecular-dynamics computer simulations have been carried out for the united-atom model of a non-crosslinked (1,4) cis-polyisoprene (PI) melt confined between two amorphous, fully coordinated silica surfaces. The Lennard-Jones 12-6 potential was implemented to describe the polymer�silica interactions. The thickness H of the produced PI�silica film has been varied in a wide range, 1 < H/R{sub g} < 8, where R{sub g} is the individual PI chain radius of gyration measured under the imposed confinement. After a thorough equilibration, the PI film stratified structure and polymer segmental dynamics have been studied. The chain structure in the middle of the films resembles that in a corresponding bulk, but the polymer-density profile shows a pronounced ordering of the polymer segments in the vicinity of silica surfaces; this ordering disappears toward the film middles. Tremendous slowing down of the polymer segmental dynamics has been observed in the film surface layers, with the segmental relaxation more than 150 times slower as compared to that in a PI bulk. This effect increases with decreasing the polymer-film thickness. The segmental relaxation in the PI film middles shows additional relaxation process which is absent in a PI bulk. Even though there are fast relaxation processes in the film middle, its overall relaxation is slower as compared to that in a bulk sample. The interpretation of the results in terms of polymer glassy bridges has been discussed.
Guseva, D. V., E-mail: firstname.lastname@example.com [Theory of Polymers and Soft Matter, Technische Universiteit Eindhoven, P.O. Box 513, 5600 MB, Eindhoven (Netherlands); Physics Department, Chair of Polymer and Crystal Physics, M. V. Lomonosov Moscow State University, 119991 Moscow (Russian Federation); Komarov, P. V. [Department of Theoretical Physics, Tver State University, Sadovyj per. 35, 170002 Tver, Russia and Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova st. 28, 119991 Moscow (Russian Federation)] [Department of Theoretical Physics, Tver State University, Sadovyj per. 35, 170002 Tver, Russia and Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova st. 28, 119991 Moscow (Russian Federation); Lyulin, Alexey V. [Theory of Polymers and Soft Matter, Technische Universiteit Eindhoven, P.O. Box 513, 5600 MB, Eindhoven (Netherlands)] [Theory of Polymers and Soft Matter, Technische Universiteit Eindhoven, P.O. Box 513, 5600 MB, Eindhoven (Netherlands)
Silica coated magnetite nanoparticles for removal of heavy metal ions from polluted waters
Magnetic removal of Hg2+ and other heavy metal ions like Cd2+, Pb2+ etc. using silica coated magnetite particles from polluted waters is a current topic of active research to provide efficient water recycling and long term high quality water. The technique used to study the bonding characteristics of such kind of nanoparticles with the heavy metal ions is a very sensitive hyperfine specroscopy technique called the perturbed angular correlation technique (PAC).
Dash, Monika
A New Concept for the Fabrication of Hydrogen Selective Silica Membranes
We are attempting to fabricate H{sub 2}-selective silica-based films by ''layer-by-layer'' deposition as a new approach for thin films. A sonication-assisted deposition method was mainly used for ''layer-by-layer'' deposition. In addition, other approaches such as a dip-coating and the use of a polymer matrix with a layered silicate were contrived as well. This report shows the progress done during the 2nd Year of this award.
Michael Tsapatsis
Effects from Alkali-Silica Reacton and Delayed Ettringite Formation on Reinforced Concrete Column Lap Splices
EFFECTS FROM ALKALI-SILICA REACTION AND DELAYED ETTRINGITE FORMATION ON REINFORCED CONCRETE COLUMN LAP SPLICES A Thesis by MARY KATHLEEN ECK Submitted to the Office of Graduate Studies of Texas A&M University in partial... by MARY KATHLEEN ECK Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved by: Chair of Committee, Joseph M. Bracci Committee Members...
Eck, Mary
Structural Assessment of D-Regions Affected by Alkali-Silica Reaction/Delayed Ettringite Formation
STRUCTURAL ASSESSMENT OF D-REGIONS AFFECTED BY ALKALI- SILICA REACTION/DELAYED ETTRINGITE FORMATION A Dissertation by SHIH-HSIANG LIU Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of the requirements for the degree of DOCTOR OF PHILOSOPHY Approved by: Chair of Committee, Joseph M. Bracci Committee Members, John B. Mander Stefan Hurlebaus Harry A. Hogan Head of Department, John M. Niedzwecki December 2012 Major Subject: Civil...
Liu, Shih-Hsiang 1979-
Thermal transport in CO2 laser irradiated fused silica: in situ measurements and analysis
In situ spatial and temporal temperature measurements of pristine fused silica surfaces heated with a 10.6 {micro}m CO{sub 2} laser were obtained using an infrared radiation thermometer based on a Mercury Cadmium Telluride (MCT) camera. Laser spot sizes ranged from 250 {micro}m to 1000 {micro}m diameter with peak axial irradiance levels of 0.13 to 16 kW/cm{sup 2}. For temperatures below 2800K, the measured steady-state surface temperature is observed to rise linearly with both increasing beam size and incident laser irradiance. The effective thermal conductivity estimated over this range was approximately 2W/mK, in good agreement with classical calculations based on phonon heat capacities. Similarly, time-dependent temperature measurements up to 2000K yielded thermal diffusivity values which were close to reported values of 7 x 10{sup -7} m{sup 2}/s. Above {approx}2800K, the fused silica surface temperature asymptotically approaches 3100K as laser power is further increased, consistent with the onset of evaporative heat losses near the silica boiling point. These results show that in the laser heating regime studied here, the T{sup 3} temperature dependent thermal conductivity due to radiation transport can be neglected, but at temperatures above 2800K heat transport due to evaporation must be considered. The thermal transport in fused silica up to 2800K, over a range of conditions, can then be adequately described by a linear diffusive heat equation assuming constant thermal properties.
Yang, S T; Matthews, M J; Elhadj, S; Draggoo, V G; Bisson, S E
Influence of phosphate and silica on U(VI) precipitation from acidic and neutralized wastewaters
Uranium speciation and physical-chemical characteristics were studied in solids precipitated from synthetic acidic to circumneutral wastewaters in the presence and absence of dissolved silica and phosphate to examine thermodynamic and kinetic controls on phase formation. Composition of synthetic wastewater was based on disposal sites 216-U-8 and 216-U-12 Cribs at the Hanford site (WA, USA). In the absence of dissolved silica or phosphate, crystalline or amorphous uranyl oxide hydrates, either compreignacite or meta-schoepite, precipitated at pH 5 or 7 after 30 d of reaction, in agreement with thermodynamic calculations. In the presence of 1 mM dissolved silica representative of groundwater concentrations, amorphous phases dominated by compreignacite precipitated rapidly at pH 5 or 7 as a metastable phase and formation of poorly-crystalline boltwoodite, the thermodynamically stable uranyl silicate phase, was slow. In the presence of phosphate (3 mM), meta-ankoleite initially precipitated as the primary phase at pH 3, 5, or 7 regardless of the presence of 1 mM dissolved silica. Analysis of precipitates by U LIII-edge EXAFS indicated that �autunite-type� sheets of meta-ankoleite transformed to �phosphuranylite-type� sheets after 30 d of reaction, probably due to Ca substitution in the structure. Low solubility of uranyl phosphate phases limits dissolved U(VI) concentrations but differences in particle size, crystallinity, and precipitate composition vary with pH and base cation concentration, which will influence the thermodynamic and kinetic stability of these phases.
Kanematsu, Masakazu; Perdrial, Nicolas; Um, Wooyong; Chorover, Jon; O'Day, Peggy A.
Origins of secondary silica within Yucca Mountain, Nye County, southwestern Nevada
The accuracy of predictions of the hydrologic response of Yucca Mountain to future climate depends largely on how well relations between past climate and hydrology can be resolved. To advance this reconstruction, secondary minerals in and near Yucca Mountain, deposited by ground waters that originated both as surficial recharge at Yucca Mountain and from regional aquifers, are being studied to determine past ground-water sources and chemistries. Preliminary data on stable oxygen isotopes indicate that, although silica (opal, quartz, and chalcedony) and calcite and have formed in similar settings and from somewhat similar fluids, the authors have found no compelling evidence of coprecipitation or formation from identical fluids. If verified by further analyses, this precludes the use of silica-calcite mineral pairs for precise geothermometry. The preliminary data also indicate that opal and calcite occurrences in pedogenic and unsaturated-zone settings are invariably compatible with formation under modern ambient surface or subsurface temperatures. Silica and calcite stable-isotope studies are being integrated with soil geochemical modeling. This modeling will define the soil geochemical condition (climate) leading to opal or calcite deposition and to the transfer functions that may apply at the meteorologic soil unsaturated-zone interfaces. Additional study of pedogenic and unsaturated-zone silica is needed to support these models. The hypothesis that the transformation of vapor-phase tridymite to quartz requires saturated conditions is being tested through stable oxygen-isotope studies of lithophysal tridymite/quartz mixtures. Should this hypothesis be verified, mineralogic analysis by X-ray diffraction theoretically would permit reconstruction of past maximum water-table elevations.
Moscati, R.J.; Whelan, J.F.
Sulfate Fining Chemistry in Oxidized and Reduced Soda-Lime-Silica Glasses
Various reducing agents were used and their additions were varied to (1) increase glass quality through eliminating defects from silica scum, (2) decrease SOx emissions through changing the kind and quantity of reducing agents, and (3) improve production efficiency through increased flexibility of glass redox control during continuous processing. The work included measuring silica sand dissolution and sulfate decomposition in melts from glass batches. Glass batches were heated at a temperature-increase rate deemed similar to that experienced in the melting furnace. The sulfate decomposition kinetics was investigated with thermogravimetric analysis-differential thermal analysis and evolved gas analysis. Sulfur concentrations in glasses quenched at different temperatures were determined using X-ray fluorescence spectroscopy. The distribution of residual sand (that which was not dissolved during the initial batch reactions) in the glass was obtained as a function of temperature with optical microscopy in thin-sections of melts. The fraction of undissolved sand was measured with X-ray diffraction. The results of the present study helped Visteon Inc. reduce the energy consumption and establish the batch containing 0.118 mass% of graphite as the best candidate for Visteon glass production. The improved glass batch has a lower potential for silica scum formation and for brown fault occurrence in the final glass product. It was established that bubbles trapped in the melt even at 1450 C have a high probability to be refined when reaching the hot zone in the glass furnace. Furthermore, silica sand does not accumulate at the glass surface and dissolves faster in the batch with graphite than in the batch with carbocite.
Matyas, Josef; Hrma, Pavel R.
Sol-gel processed silica-alumina materials for diesel engine emission reduction catalysts
The incorporation of >30% silica in alumina prior to platinum impregnation improves the NOx conversion efficiency in the 200--300 C range from 45 to 57% and reduces light-off temperature. Further increase in the amount of silica to 50% is detrimental to NOx conversion efficiency. The {sup 1}H and {sup 29}Si NMR of the materials suggest that this trend is probably related to the surface acidity. The analyses of these materials by X-ray powder diffraction and electron microscopy do not reveal significant differences. Additional NOx conversion in the 350--450 C range with a maximum of 30% at 400 C can be achieved if a rhodium-impregnated 30% silica-alumina, Rh-30% SiO{sub 2}-Al{sub 2}O{sub 3}, is placed upstream of Pt-30% SiO{sub 2}-Al{sub 2}O{sub 3}. It is important to note that mixing Pt-30% SiO{sub 2}-Al{sub 2}O{sub 3} with Rh-30% SiO{sub 2}-Al{sub 2}O{sub 3} does not enhance conversion efficiency or effective temperature range.
Narula, C.K.; Rokosz, M.; Allard, L.F.; Kudla, R.J.; Chattha, M.S.
Controlled epitaxial growth of mesoporous silica/gold nanorod nanolollipops and nanodumb-bells
In this work, we describe the controlled synthesis of novel heterogeneous nanostructures comprised of mesoporous silica-coated gold nanorods (MSGNRs) in the form of core�shell nanolollipops and nanodumb-bells, using a seed-mediated sol�gel method. Although MSGNR core�shell (?-MSGNR) structures have been reported previously by us and others, we herein discuss the first ever fabrication of MSGNR nanolollipops (?-MSGNR) and nanodumb-bells (?-MSGNR), achieved by simply controlling the aging time of gold nanorods (GNRs), the residual cetyltrimethylammonium bromide (CTAB) coating of GNRs, and the addition of dimethyl formamide during incubation, centrifugation, and sonication, respectively. Transmission electron microscopy revealed two bare GNR isoforms, with aspect ratios of approximately 4 and 6, while scanning electron microscopy was used to further elucidate the morphology of ?-MSGNR and ?-MSGNR heterostructures. In agreement with the smaller dielectric constants afforded by incomplete silica encasement, spectroscopic studies of ?-MSGNR and ?-MSGNR, surface plasmon resonance (SPR) bands revealed 20-40 nm blue shifts relative to the SPR of ?-MSGNR. On the basis of the attributes and applications of more conventional ?-MSGNRs, ?-MSGNRs and ?-MSGNRs are anticipated to provide most of the utility of ?-MSGNRs, but with the additional functionalities that accompany their incorporation of both bare gold and mesoporous silica encased tips; with significant/unique implications for biomedical and catalytic applications.
Huang, Ching-Mao [Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, 35 Keyan Road, Zhunan Town, Miaoli 35053, Taiwan (China); Material and Chemical Laboratories, Industrial Technology Research Institute, Hsinchu 30011, Taiwan (China); Chung, Ming-Fang; Lo, Leu-Wei, E-mail: firstname.lastname@example.com [Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, 35 Keyan Road, Zhunan Town, Miaoli 35053, Taiwan (China); Souris, Jeffrey S. [Department of Radiology, The University of Chicago, Chicago, Illinois 60637 (United States)
4June2013 Page 1 of 8 Sodium Hydroxide (Pellets) SOP Standard Operating Procedures
4June2013 Page 1 of 8 Sodium Hydroxide (Pellets) SOP Standard Operating Procedures Strong Corrosives Strong Bases (SB) Sodium Hydroxide (Pellets) PrintOH Form: pellets Color: white Melting point/freezing point: 318 °C (604 °F
Cohen, Ronald C.
Sequential Treatment by Ionizing Radiation and Sodium Arsenite Dramatically Accelerates TRAIL-Mediated Apoptosis of
is critically important in the translocation of death receptor to the cell surface. Moreover, sodium arsenite and further down-regulates cFLIP levels in melanoma cells. We have evaluated the effects of sequentialSequential Treatment by Ionizing Radiation and Sodium Arsenite Dramatically Accelerates TRAIL
Effect of sodium chloride concentration on the heat resistance and recovery of
Effect of sodium chloride concentration on the heat resistance and recovery of Salmonella inhibitory effect in the recovery media. Keywords : Salmonella typhimurium, Sodium chloride, Heat treatment, but they also generate damaged cells. The ability of heated cells to survive depends on the recovery conditions
Paris-Sud XI, Universit� de
Sodium fast reactor fuels and materials : research needs.
An expert panel was assembled to identify gaps in fuels and materials research prior to licensing sodium cooled fast reactor (SFR) design. The expert panel considered both metal and oxide fuels, various cladding and duct materials, structural materials, fuel performance codes, fabrication capability and records, and transient behavior of fuel types. A methodology was developed to rate the relative importance of phenomena and properties both as to importance to a regulatory body and the maturity of the technology base. The technology base for fuels and cladding was divided into three regimes: information of high maturity under conservative operating conditions, information of low maturity under more aggressive operating conditions, and future design expectations where meager data exist.
Denman, Matthew R.; Porter, Douglas (Idaho National Laboratory, Idaho Falls, ID); Wright, Art (Argonne National Laboratory Argonne, IL); Lambert, John (Argonne National Laboratory Argonne, IL); Hayes, Steven (Idaho National Laboratory, Idaho Falls, ID); Natesan, Ken (Argonne National Laboratory Argonne, IL); Ott, Larry J. (Oak Ridge National Laboratory, Oak Ridge, TN); Garner, Frank (Radiation Effects Consulting. Richland, WA); Walters, Leon (Advanced Reactor Concepts, Idaho Falls, ID); Yacout, Abdellatif (Argonne National Laboratory Argonne, IL)
Sodium-Bearing Waste Treatment Alternatives Implementation Study
The purpose of this document is to discuss issues related to the implementation of each of the five down-selected INEEL/INTEC radioactive liquid waste (sodium-bearing waste - SBW) treatment alternatives and summarize information in three main areas of concern: process/technical, environmental permitting, and schedule. Major implementation options for each treatment alternative are also identified and briefly discussed. This report may touch upon, but purposely does not address in detail, issues that are programmatic in nature. Examples of these include how the SBW will be classified with respect to the Nuclear Waste Policy Act (NWPA), status of Waste Isolation Pilot Plant (WIPP) permits and waste storage availability, available funding for implementation, stakeholder issues, and State of Idaho Settlement Agreement milestones. It is assumed in this report that the SBW would be classified as a transuranic (TRU) waste suitable for disposal at WIPP, located in New Mexico, after appropriate treatment to meet transportation requirements and waste acceptance criteria (WAC).
Charles M. Barnes; James B. Bosley; Clifford W. Olsen
Feasibility Study for Vitrification of Sodium-Bearing Waste
Treatment of sodium-bearing waste (SBW) at the Idaho Nuclear Technology and Engineering Center (INTEC) within the Idaho National Engineering and Environmental Laboratory is mandated under a Settlement Agreement between the Department of Energy and the State of Idaho. One of the requirements of the Settlement Agreement is the complete calcination (i.e., treatment) of all SBW by December 31, 2012. One of the proposed options for treatment of SBW is vitrification. This study will examine the viability of SBW vitrification. This study describes the process and facilities to treat the SBW, from beginning waste input from INTEC Tank Farm to the final waste forms. Schedules and cost estimates for construction and operation of a Vitrification Facility are included. The study includes a facility layout with drawings, process description and flow diagrams, and preliminary equipment requirements and layouts.
J. J. Quigley; B. D. Raivo; S. O. Bates; S. M. Berry; D. N. Nishioka; P. J. Bunnell
Sodium Heat Engine Development Program. Phase 1, Final report
The Sodium Heat Engine (SHE) is an efficient thermoelectric conversion device which directly generates electricity from a thermally regenerative electrochemical cell that relies on the unique conduction properties of {beta}{double_prime}-alumina solid electrolyte (BASE). Laboratory models of a variety of SHE devices have demonstrated the feasibility and efficiency of the system, engineering development of large prototype devices has been slowed by a series of materials and fabrication problems. Failure of the electrolyte tubes has been a recurring problem and a number of possible causes have been postulated. To address these issues, a two-phase engineering development program was undertaken. This report summarizes the final results of the first phase of the program, which included extensive materials characterization activities, a study of applicable nondestructive evaluation methods, an investigation of possible stress states that would contribute to fracture, and certain operational issues associated with the electromagnetic pumps used in the SHE prototype. Mechanical and microstructural evaluation of commercially obtained BASE tubes revealed that they should be adequate for SHE applications and that sodium exposure produced no appreciable deleterious strength effects. Processing activities to produce a more uniform and smaller grain size for the BASE tubes were completed using isostatic pressing, extrusion, and slip casting. Green tubes were sintered by conventional and microwave plasma methods. Of particular interest is the residual stress state in the BASE tubes, and both analysis and nondestructive evaluation methods were employed to evaluate these stresses. X-ray and neutron diffraction experiments were performed to determine the bulk residual stresses in commercially fabricated BASE tubes; however, tube-to-tube variations and variations among the various methods employed did not allow formulation of a definitive definition of the as-fabricated stress state.
105-DR Large Sodium Fire Facility closure plan. Revision 1
The Hanford Site, located northwest of the city of Richland, Washington, houses reactors, chemical-separation systems, and related facilities used for the production of special nuclear materials, and activities associated with nuclear energy development. The 105-DR Large Sodium Fire Facility (LSFF), which was in operation from about 1972 to 1986, was a research laboratory that occupied the former ventilation supply room on the southwest side of the 105-DR Reactor facility. The LSFF was established to provide a means of investigating fire and safety aspects associated with large sodium or other metal alkali fires in the liquid metal fast breeder reactor (LMFBR) facilities. The 105-DR Reactor facility was designed and built in the 1950`s and is located in the 100-D Area of the Hanford Site. The building housed the 105-DR defense reactor, which was shut down in 1964. The LSFF was initially used only for engineering-scale alkali metal reaction studies. In addition, the Fusion Safety Support Studies program sponsored intermediate-size safety reaction tests in the LSFF with lithium and lithium lead compounds. The facility has also been used to store and treat alkali metal waste, therefore the LSFF is subject to the regulatory requirements for the storage and treatment of dangerous waste. Closure will be conducted pursuant to the requirements of the Washington Administrative Code (WAC) 173-303-610. This closure plan presents a description of the facility, the history of waste managed, and the procedures that will be followed to close the LSFF as an Alkali Metal Treatment Facility. No future use of the LSFF is expected.
Dendrimer Templated Synthesis of One Nanometer Rh and Pt Particles Supported on Mesoporous Silica: Catalytic Activity for Ethylene and Pyrrole Hydrogenation.
Scheme 2) and pyrrole hydrogenation (Scheme 3). Synthesis ofSynthesis of One Nanometer Rh and Pt Particles Supported on Mesoporous Silica: Catalytic Activity for Ethylene and Pyrrole
Huang, Wenyu
The objective of this research is to explore new liquid-liquid extraction approaches to the selective separation of major sodium salts from alkaline high-level wastes stored in underground tanks at Hanford, Savannah River, and Oak Ridge sites. Disposal of high level waste is horrendously expensive, in large part because the actual radioactive matter in the tanks has been diluted over 1000-fold by ordinary inorganic chemicals. Since the residual bulk chemicals must still undergo expensive treatment and disposal after most of the hazardous radionuclides have been removed, large cost savings will result from processes that reduce the overall waste volume. It is proposed that major cost savings can be expected if sodium hydroxide needed for sludge washing can be obtained from the waste itself, thus avoiding the addition of yet another bulk chemical to the waste and still further increase of the waste volume and disposal cost. Secondary priority is given to separating potassium an d abundant anions, including nitrate, nitrite, aluminate, and carbonate. Salts of these ions represent possible additional value for recycle, alternative disposal, or even use as commodity chemicals. A comprehensive approach toward understanding the extractive chemistry of these salts is envisioned, involving systems of varying complexity, from use of simple solvents to new bifunctional host molecules for ion-pair recognition. These extractants will ideally require no adjustment of the waste composition and will release the extracted salt into water, thereby consuming no additional chemicals and producing no additional waste volume. The overall goal of this research is to provide a scientific foundation upon which the feasibility of new liquid-liquid extraction chemistry applicable to the bulk reduction of the volume of tank waste can be evaluated.
Moyer, Bruce A.; Marchand, Alan P.; Bryan, Jeffrey C.; Bonnesen, Peter V.
Mercury's sodium exosphere: Magnetospheric ion recycling Service d'Aeronomie du CNRS/IPSL, Verrie`res-Le-Buisson, France
Mercury's sodium exosphere: Magnetospheric ion recycling F. Leblanc Service d'Ae´ronomie du CNRS December 2003. [1] A three-dimensional Monte Carlo model of Mercury's neutral sodium exosphere was used in the surface concentration of sodium along Mercury's motion around the Sun [Leblanc and Johnson, 2003]. Four
Analysis and methodology for measuring oxygen concentration in liquid sodium with a plugging meter
Oxygen concentration in liquid sodium is a critical measurement in assessing the potential for corrosion damage in sodium-cooled fast reactors (SFRs). There has been little recent work on sodium reactors and oxygen detection. Thus, the technical expertise dealing with oxygen measurements within sodium is no longer readily available in the U.S. Two methods of oxygen detection that have been investigated are the plugging meter and the galvanic cell. One of the overall goals of the Univ. of Wisconsin's sodium research program is to develop an affordable, reliable galvanic cell oxygen sensor. Accordingly, attention must first be dedicated to a well-known standard known as a plugging meter. Therefore, a sodium loop has been constructed on campus in effort to develop the plugging meter technique and gain experience working with liquid metal. The loop contains both a galvanic cell test section and a plugging meter test section. Consistent plugging results have been achieved below 20 [wppm], and a detailed process for achieving effective plugging has been developed. This paper will focus both on an accurate methodology to obtain oxygen concentrations from a plugging meter, and on how to easily control the oxygen concentration of sodium in a test loop. Details of the design, materials, manufacturing, and operation will be presented. Data interpretation will also be discussed, since a modern discussion of plugging data interpretation does not currently exist. (authors)
Nollet, B. K.; Hvasta, M.; Anderson, M. [Univ. of Wisconsin-Madison, 1500 Engineering Dr., Madison, WI 53706 (United States)
Magnetic properties of magnetite nanoparticles coated with mesoporous silica by sonochemical method
Highlights: Black-Right-Pointing-Pointer MCM-41-coating of magnetite nanoparticles performed under ultrasonic irradiation. Black-Right-Pointing-Pointer Ultrasonic irradiation accelerates the formation of the MCM-41 framework. Black-Right-Pointing-Pointer The hysteretic response to an applied field was investigated applying FORC diagram. Black-Right-Pointing-Pointer The average coercive field of the Fe{sub 3}O{sub 4} nanoparticles increased after coating. -- Abstract: In this paper we present the magnetic properties of mesoporous silica-coated Fe{sub 3}O{sub 4} nanoparticles. The coating of magnetite nanoparticles with mesoporous silica shell was performed under ultrasonic irradiation. The obtained mesoporous silica-coated magnetite nanoparticles were characterized by powder X-ray diffraction, focused ion beam-scanning electron microscopy, nitrogen adsorption-desorption isotherms and vibrating sample magnetometer. The hysteretic behavior was studied using first-order reversal curves diagrams. The X-ray diffraction result indicates that the extreme chemical and physical conditions created by acoustic cavitations have an insignificant effect on crystallographic structural characteristic of magnetite nanoparticles. Changes in the coercivity distributions of the magnetite nanoparticles were observed on the first-order reversal curves diagrams for the samples with coated particles compared with the samples containing uncoated particles of magnetite. The coated particles show an increased most probable coercivity of about 20% compared with the uncoated particles which can be associated with an increased anisotropy due to coating even if the interaction field distribution measured on the diagrams are virtually identical for coated/uncoated samples.
Ursachi, Irina [Department of Physics and CARPATH Center, 'Alexandru Ioan Cuza' University of Iasi, 11 Carol I Blvd., 700506 Iasi (Romania)] [Department of Physics and CARPATH Center, 'Alexandru Ioan Cuza' University of Iasi, 11 Carol I Blvd., 700506 Iasi (Romania); Vasile, Aurelia [Department of Chemistry, 'Alexandru Ioan Cuza' University of Iasi, 11 Carol I Blvd., 700506 Iasi (Romania)] [Department of Chemistry, 'Alexandru Ioan Cuza' University of Iasi, 11 Carol I Blvd., 700506 Iasi (Romania); Chiriac, Horia [National Institute of Research and Development for Technical Physics, 47 Mangeron Blvd., 700050 Iasi (Romania)] [National Institute of Research and Development for Technical Physics, 47 Mangeron Blvd., 700050 Iasi (Romania); Postolache, Petronel [Department of Physics and CARPATH Center, 'Alexandru Ioan Cuza' University of Iasi, 11 Carol I Blvd., 700506 Iasi (Romania)] [Department of Physics and CARPATH Center, 'Alexandru Ioan Cuza' University of Iasi, 11 Carol I Blvd., 700506 Iasi (Romania); Stancu, Alexandru, E-mail: firstname.lastname@example.com [Department of Physics and CARPATH Center, 'Alexandru Ioan Cuza' University of Iasi, 11 Carol I Blvd., 700506 Iasi (Romania)] [Department of Physics and CARPATH Center, 'Alexandru Ioan Cuza' University of Iasi, 11 Carol I Blvd., 700506 Iasi (Romania)
Reduction and aggregation of silver in aqueous gelatin and silica suspensions
The investigation of silver reduction and aggregation processes are of specific interest to the photographic industry, which relies heavily on photochemical equivalents of these reactions. Mechanistic insights into the formation of small silver clusters in aqueous solution have been obtained from both pulse and {gamma}-radiolytic studies. This paper examines the reduction of silver ions and the subsequent formation of silver clusters in aqueous gelatin solutions and on colloidal silica particles using the pulse radiolysis technique. The aggregation processes are compared with the parallel reactions in aqueous solutions.
Kapoor, S.; Lawless, D.; Kennepohl, P.; Meisel, D. [Argonne National Lab., IL (United States); Serpone, N. [Concordia Univ., Montreal, Quebec (Canada)
Femtosecond diffraction dynamics of laser-induced periodic surface structures on fused silica
The formation of laser-induced periodic surface structures (LIPSS) on fused silica upon irradiation with linearly polarized fs-laser pulses (50 fs pulse duration, 800 nm center wavelength) is studied experimentally using a transillumination femtosecond time-resolved (0.1 ps-1 ns) pump-probe diffraction approach. This allows to reveal the generation dynamics of near-wavelength-sized LIPSS showing a transient diffraction at specific spatial frequencies even before a corresponding permanent surface relief was observed. The results confirm that the ultrafast energy deposition to the materials surface plays a key role and triggers subsequent physical mechanisms such as carrier scattering into self-trapped excitons.
Hoehm, S.; Rosenfeld, A. [Max-Born-Institut fuer Nichtlineare Optik und Kurzzeitspektroskopie (MBI), Max-Born-Strasse 2A, D-12489 Berlin (Germany)] [Max-Born-Institut fuer Nichtlineare Optik und Kurzzeitspektroskopie (MBI), Max-Born-Strasse 2A, D-12489 Berlin (Germany); Krueger, J.; Bonse, J. [BAM Bundesanstalt fuer Materialforschung und - pruefung, Unter den Eichen 87, D-12205 Berlin (Germany)] [BAM Bundesanstalt fuer Materialforschung und - pruefung, Unter den Eichen 87, D-12205 Berlin (Germany)
Laser induced damage of fused silica polished optics due to a droplet forming organic contaminant
We report on the effect of organic molecular contamination on single shot laser induced damage density at the wavelength of 351 nm, with a 3 ns pulse length. Specific contamination experiments were made with dioctylphthalate (DOP) in liquid or gaseous phase, on the surface of fused silica polished samples, bare or solgel coated. Systematic laser induced damage was observed only in the case of liquid phase contamination. Different chemical and morphological characterization methods were used to identify and understand the damage process. We demonstrate that the contaminant morphology, rather than its physicochemical nature, can be responsible for the decrease of laser induced damage threshold of optics.
Bien-Aime, Karell; Neauport, Jerome; Tovena-Pecault, Isabelle; Fargin, Evelyne; Labrugere, Christine; Belin, Colette; Couzi, Michel
Mesoporous Silica Nanomaterials for Applications in Catalysis, Sensing, Drug Delivery and Gene Transfection
The central theme of this dissertation is represented by the versatility of mesoporous silica nanomaterials in various applications such as catalysis and bio-applications, with main focus on biological applications of Mesoporous Silica Nanospheres (MSN). The metamorphosis that we impose to these materials from catalysis to sensing and to drug and gene delivery is detailed in this dissertation. First, we developed a synthetic method that can fine tune the amount of chemically accessible organic functional groups on the pores surface of MSN by exploiting electrostatic and size matching between the cationic alkylammonium head group of the cetyltrimethylammonium bromide (CTAB) surfactant and various anionic organoalkoxysilane precursors at the micelle-water interface in a base-catalyzed condensation reaction of silicate. Aiming nature imitation, we demonstrated the catalytic abilities of the MSNs, We utilized an ethylenediamine functional group for chelating Cu{sup 2+} as a catalytic functional group anchored inside the mesopores. Thus, a polyalkynylene-based conducting polymer (molecular wire) was synthesized within the Cu-functionalized MSNs silica catalyst. For sensing applications, we have synthesized a poly(lactic acid) coated mesoporous silica nanosphere (PLA-MSN) material that serves as a fluorescence sensor system for detection of amino-containing neurotransmitters in neutral aqueous buffer. We exploited the mesoporosity of MSNs for encapsulating pharmaceutical drugs. We examined bio-friendly capping molecules such as polyamidoamine dendrimers of generations G2 to G4, to prevent the drug leaching. Next, the drug delivery system employed MSNs loaded with Doxorubicin, an anticancer drug. The results demonstrated that these nano-Trojan horses have ability to deliver Doxorubicin to cancer cells and induce their death. Finally, to demonstrate the potential of MSN as an universal cellular transmembrane nanovehicle, we anchored positively charged dendrimers on the surface of MSN and utilize them to complex cationic DNA. The p-EGFP-CI gene-coated MSN nanocomposite was able to transfect cancer cell lines, such as human HeLa and CHO cancer cell lines. The gene carrier ability of MSNs was further proved by transfecting primary cells and cotransfecting of two different genes in cancer cell lines. In sum, MSN are versatile partners in several types of applications.
Daniela Rodica Radu
Environmental, health, and safety issues of sodium-sulfur batteries for electric and hybrid vehicles
This report examines the shipping regulations that govern the shipment of dangerous goods. Since the elemental sodium contained in both sodium-sulfur and sodium-metal-chloride batteries is classified as a dangerous good, and is listed on both the national and international hazardous materials listings, both national and international regulatory processes are considered in this report The interrelationships as well as the differences between the two processes are highlighted. It is important to note that the transport regulatory processes examined in this report are reviewed within the context of assessing the necessary steps needed to provide for the domestic and international transport of sodium-beta batteries. The need for such an assessment was determined by the Shipping Sub-Working Group (SSWG) of the EV Battery Readiness Working Group (Working Group), created in 1990. The Working Group was created to examine the regulatory issues pertaining to in-vehicle safety, shipping, and recycling of sodium-sulfur batteries, each of which is addressed by a sub-working group. The mission of the SSWG is to establish basic provisions that will ensure the safe and efficient transport of sodium-beta batteries. To support that end, a proposal to the UN Committee of Experts was prepared by the SSWG, with the goal of obtaining a proper shipping name and UN number for sodium-beta batteries and to establish the basic transport requirements for such batteries (see the appendix for the proposal as submitted). It is emphasized that because batteries are large articles containing elemental sodium and, in some cases, sulfur, there is no existing UN entry under which they can be classified and for which modal transport requirements, such as the use of packaging appropriate for such large articles, are provided for. It is for this reason that a specific UN entry for sodium-beta batteries is considered essential.
Hammel, C.J.
X-ray spectroscopy study of electronic structure of laser-irradiated Au nanoparticles in a silica film
The electronic structure of gold nanoparticles embedded in a silica film is studied, both before and after irradiation at 355 nm by a laser. The Au 5d occupied valence states are observed by x-ray emission spectroscopy. They show that before irradiation the gold atoms are in metallic states within the nanoparticles. After irradiation with a fluence of 0.5 J/cm{sup 2}, it is found that gold valence states are close to those of a metal-poor gold silicide; thanks to a comparison of the experimental Au 5d states with the calculated ones for gold silicides using the density-functional theory. The formation of such a compound is driven by the diffusion of the gold atoms into the silica film upon the laser irradiation. At higher fluence, 1 J/cm{sup 2}, we find a higher percentage of metallic gold that could be attributed to annealing in the silica matrix.
Jonnard, P.; Bercegol, H.; Lamaignere, L.; Morreeuw, J.-P.; Rullier, J.-L.; Cottancin, E.; Pellarin, M. [Laboratoire de Chimie Physique-Matiere et Rayonnement, Universite Pierre et Marie Curie, Centre National de la Recherche Scientifique Unite Mixte de Recherche (CNRS UMR) 7614, 11 rue Pierre et Marie Curie, F-75231 Paris Cedex 05 (France); Commissariat a l'Energie Atomique/Centre d'Etudes Scientifiques et Techniques d'Aquitaine (CEA/CESTA), BP 2, F-33114, Le Barp (France); Centre Agregat Laboratoire de Spectrometrie Ionique et Moleculaire (LASIM) et Laboratoire de Physique de la Matiere Condensee et Nanostructures (LPMCN), Universite Claude Bernard Lyon I, F-69622 Villeurbanne (France)
Tolerance Test of Eisenia Fetida for Sodium Chloride
Saltwater spills that make soil excessively saline often occur at petroleum exploration and production (E&P) sites and are ecologically damaging. Brine scars appear when produced water from an E&P site is spilled onto surrounding soil, causing loss of vegetation and subsequent soil erosion. Revegetating lands damaged by brine water can be difficult. The research reported here considers earthworms as a bioremedial treatment for increasing the salt mobility in this soil and encouraging plant growth and a healthy balance of soil nutrients. To determine the practical application of earthworms to remediate brine-contaminated soil, a 17-d test was conducted to establish salt tolerance levels for the common compost earthworm (Eisenia fetida) and relate those levels to soil salinity at brine-spill sites. Soil samples were amended with sodium chloride in concentrations ranging from 1 to 15 g/kg, which represent contamination levels at some spill sites. The survival rate of the earthworms was near 90% in all tested concentrations. Also, reproduction was noted in a number of the lower-concentration test replicates but absent above the 3-g/kg concentrations. Information gathered in this investigation can be used as reference in further studies of the tolerance of earthworms to salty soils, as results suggest that E. fetida is a good candidate to enhance remediation at brine-damaged sites.
Kerr, M.; Stewart, A.J.
Sodium-bearing Waste Treatment Technology Evaluation Report
Sodium-bearing waste (SBW) disposition is one of the U.S. Department of Energy (DOE) Idaho Operation Office�s (NE-ID) and State of Idaho�s top priorities at the Idaho National Engineering and Environmental Laboratory (INEEL). The INEEL has been working over the past several years to identify a treatment technology that meets NE-ID and regulatory treatment requirements, including consideration of stakeholder input. Many studies, including the High-Level Waste and Facilities Disposition Environmental Impact Statement (EIS), have resulted in the identification of five treatment alternatives that form a short list of perhaps the most appropriate technologies for the DOE to select from. The alternatives are (a) calcination with maximum achievable control technology (MACT) upgrade, (b) steam reforming, (c) cesium ion exchange (CsIX) with immobilization, (d) direct evaporation, and (e) vitrification. Each alternative has undergone some degree of applied technical development and preliminary process design over the past four years. This report presents a summary of the applied technology and process design activities performed through February 2004. The SBW issue and the five alternatives are described in Sections 2 and 3, respectively. Details of preliminary process design activities for three of the alternatives (steam reforming, CsIX, and direct evaporation) are presented in three appendices. A recent feasibility study provides the details for calcination. There have been no recent activities performed with regard to vitrification; that section summarizes and references previous work.
Charles M. Barnes; Arlin L. Olson; Dean D. Taylor
Formation of laser-induced periodic surface structures on fused silica upon two-color double-pulse irradiation
The formation of laser-induced periodic surface structures (LIPSS) upon irradiation of fused silica with multiple irradiation sequences consisting of laser pulse pairs (50 fs single-pulse duration) of two different wavelengths (400 and 800 nm) is studied experimentally. Parallel polarized double-pulse sequences with a variable delay ?t between ?10 and +10 ps and between the individual fs-laser pulses were used to investigate the LIPSS periods versus ?t. These two-color experiments reveal the importance of the ultrafast energy deposition to the silica surface by the first laser pulse for LIPSS formation. The second laser pulse subsequently reinforces the previously seeded spatial LIPSS frequencies.
H�hm, S.; Herzlieb, M.; Rosenfeld, A. [Max-Born-Institut f�r Nichtlineare Optik und Kurzzeitspektroskopie (MBI), Max-Born-Stra�e 2A, D-12489 Berlin (Germany)] [Max-Born-Institut f�r Nichtlineare Optik und Kurzzeitspektroskopie (MBI), Max-Born-Stra�e 2A, D-12489 Berlin (Germany); Kr�ger, J.; Bonse, J. [BAM Bundesanstalt f�r Materialforschung und �pr�fung, Unter den Eichen 87, D-12205 Berlin (Germany)] [BAM Bundesanstalt f�r Materialforschung und �pr�fung, Unter den Eichen 87, D-12205 Berlin (Germany)
The effect of silica gel sampling tube design on the analytical recovery of fluorine ions / by Daniel Howard Anna
concentrations of hydrofluoric acid. The statically generated concentrations ranged from 0. 5 to 2. 5 times the TLV. The first type of hand packed tube used foam, rather than glass wool, to hold the silica gel in place. The other type had silica gel sections... and the analyzed concentrations showed that the tubes were not statistically different at the 95% confidence level. ACKNOWLEDGMENT I would like to thank the members of my committee, Richard B. Konzen, Ph. D. , John P. Wagner, Ph. D. and Calvin B. Parnell, Ph. D...
Anna, Daniel Howard
We demonstrate a new class of hollow-core Bragg fibers that are composed of concentric cylindrical silica rings separated by nanoscale support bridges. We theoretically predict and experimentally observe hollow-core confinement over an octave frequency range. The bandwidth of bandgap guiding in this new class of Bragg fibers exceeds that of other hollow-core fibers reported in the literature. With only three rings of silica cladding layers, these Bragg fibers achieve propagation loss of the order of 1 dB/m.
Vienne, G; Jakobsen, C; Deyerl, H J; Jensen, J B; Sorensen, T; Hansen, T P; Huang, Y; Terrel, M; Lee, R K; Mortensen, N A; Broeng, J; Simonsen, H; Bjarklev, A; Yariv, A
Dynamics of tungsten hexacarbonyl, dicobalt octacarbonyl, and their fragments adsorbed on silica surfaces
Tungsten and cobalt carbonyls adsorbed on a substrate are typical starting points for the electron beam induced deposition of tungsten or cobalt based metallic nanostructures. We employ first principles molecular dynamics simulations to investigate the dynamics and vibrational spectra of W(CO){sub 6} and W(CO){sub 5} as well as Co{sub 2}(CO){sub 8} and Co(CO){sub 4} precursor molecules on fully and partially hydroxylated silica surfaces. Such surfaces resemble the initial conditions of electron beam induced growth processes. We find that both W(CO){sub 6} and Co{sub 2}(CO){sub 8} are stable at room temperature and mobile on a silica surface saturated with hydroxyl groups (OH), moving up to half an Angstr�m per picosecond. In contrast, chemisorbed W(CO){sub 5} or Co(CO){sub 4} ions at room temperature do not change their binding site. These results contribute to gaining fundamental insight into how the molecules behave in the simulated time window of 20 ps and our determined vibrational spectra of all species provide signatures for experimentally distinguishing the form in which precursors cover a substrate.
Muthukumar, Kaliappan; Valent�, Roser; Jeschke, Harald O. [Institut f�r Theoretische Physik, Goethe-Universit�t Frankfurt, Max-von-Laue-Stra�e 1, 60438 Frankfurt am Main (Germany)] [Institut f�r Theoretische Physik, Goethe-Universit�t Frankfurt, Max-von-Laue-Stra�e 1, 60438 Frankfurt am Main (Germany)
Fractures and fracture networks are the principal pathways for migration of water and contaminants in groundwater systems, fluids in enhanced geothermal systems (EGS), oil and gas in petroleum reservoirs, carbon dioxide leakage from geological carbon sequestration, and radioactive and toxic industrial wastes from underground storage repositories. When dealing with EGS fracture networks, there are several major issues to consider, e.g., the minimization of hydraulic short circuits and losses of injected geothermal fluid to the surrounding formation, which in turn maximize heat extraction and economic production. Gel deployments to direct and control fluid flow have been extensively and successfully used in the oil industry for enhanced oil recovery. However, to the best of our knowledge, gels have not been applied to EGS to enhance heat extraction. In-situ gelling systems can either be organic or inorganic. Organic polymer gels are generally not thermostable to the typical temperatures of EGS systems. Inorganic gels, such as colloidal silica gels, however, may be ideal blocking agents for EGS systems if suitable gelation times can be achieved. In the current study, we explore colloidal silica gelation times and rheology as a function of SiO{sub 2} concentration, pH, salt concentration, and temperature, with preliminary results in the two-phase field above 100 C. Results at 25 C show that it may be possible to choose formulations that will gel in a reasonable and predictable amount of time at the temperatures of EGS systems.
Hunt, J D; Ezzedine, S M; Bourcier, W; Roberts, S
Molecular dynamics simulation of shock induced ejection on fused silica surface
Shock response and surface ejection behaviors of fused silica are studied by using non-equilibrium molecular dynamics combining with the Tersoff potential. First, bulk structure and Hugoniot curves of fused silica are calculated and compared with experimental results. Then, the dynamical process of surface ejection behavior is simulated under different loading velocities ranging from 3.5 to 5.0?km?s, corresponding to shock wave velocities from 7.1 to 8.8?km?s. The local atomistic shear strain parameter is used to describe the local plastic deformation under conditions of shock compression or releasing. Our result shows that the shear strain is localized in the bottom area of groove under the shock compression. Surface ejection is observed when the loading velocity exceeds 4.0?km?s. Meanwhile, the temperature of the micro-jet is ?5574.7?K, which is close to experiment measurement. Several kinds of structural defects including non-bridging oxygen are found in the bulk area of the sample after ejection.
Su, Rui [College of Physical Science and Technology, Sichuan University, Chengdu 610064 (China); Xiang, Meizhen; Jiang, Shengli [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Chen, Jun, E-mail: email@example.com [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Center for Applied Physics and Technology, Peking University, Beijing 100087 (China); Wei, Han [Research Center of Laser Fusion, Mianyang 621900 (China)
Interfacial water on crystalline silica: A comparative molecular dynamics simulation study
All-atom molecular dynamics simulations were conducted to study the dynamics of aqueous electrolyte solutions confined in slit-shaped silica nanopores of various degrees of protonation. Five degrees of protonation were prepared by randomly removing surface hydrogen atoms from fully protonated crystalline silica surfaces. Aqueous electrolyte solutions containing NaCl or CsCl salt were simulated at ambient conditions. In all cases, the ionic concentration was 1 M. The results were quantified in terms of atomic density distributions within the pores, and the self-diffusion coefficient along the direction parallel to the pore surface. We found evidence for ion-specific properties that depend on ion surface, water ion, and only in some cases ion ion correlations. The degree of protonation strongly affects the structure, distribution, and the dynamic behavior of confined water and electrolytes. Cl ions adsorb on the surface at large degrees of protonation, and their behavior does not depend significantly on the cation type (either Na+ or Cs+ ions are present in the systems considered). The cations show significant ion-specific behavior. Na+ ions occupy different positions within the pore as the degree of protonation changes, while Cs+ ions mainly remain near the pore center at all conditions considered. For a given degree of protonation, the planar self-diffusion coefficient of Cs+ is always greater than that of Na+ ions. The results are useful for better understanding transport under confinement, including brine behavior in the subsurface, with important applications such as environmental remediation.
Ho, Tuan A. [University of Oklahoma, Norman; Argyris, D. [University of Oklahoma, Norman; Cole, David [Ohio State University; Striolo, Alberto [Oklahoma University
Power scaling analysis of fiber lasers and amplifiers based on non-silica materials
A developed formalism for analyzing the power scaling of diffraction limited fiber lasers and amplifiers is applied to a wider range of materials. Limits considered include thermal rupture, thermal lensing, melting of the core, stimulated Raman scattering, stimulated Brillouin scattering, optical damage, bend induced limits on core diameter and limits to coupling of pump diode light into the fiber. For conventional fiber lasers based upon silica, the single aperture, diffraction limited power limit was found to be 36.6kW. This is a hard upper limit that results from an interaction of the stimulated Raman scattering with thermal lensing. This result is dependent only upon physical constants of the material and is independent of the core diameter or fiber length. Other materials will have different results both in terms of ultimate power out and which of the many limits is the determining factor in the results. Materials considered include silica doped with Tm and Er, YAG and YAG based ceramics and Yb doped phosphate glass. Pros and cons of the various materials and their current state of development will be assessed. In particular the impact of excess background loss on laser efficiency is discussed.
Dawson, J W; Messerly, M J; Heebner, J E; Pax, P H; Sridharan, A K; Bullington, A L; Beach, R J; Siders, C W; Barty, C P; Dubinskii, M
Study of a Threshold Cherenkov Counter Based on Silica Aerogels with Low Refractive Indices
To identify $\\pi^{\\pm}$ and $K^{\\pm}$ in the region of $1.0\\sim 2.5$ GeV/c, a threshold Cherenkov counter equipped with silica aerogels has been investigated. Silica aerogels with a low refractive index of 1.013 have been successfully produced using a new technique. By making use of these aerogels as radiators, we have constructed a Cherenkov counter and have checked its properties in a test beam. The obtained results have demonstrated that our aerogel was transparent enough to make up for loss of the Cherenkov photon yield due to a low refractive index. Various configurations for the photon collection system and some types of photomultipliers, such as the fine-mesh type, for a read out were also tested. From these studies, our design of a Cherenkov counter dedicated to $\\pi / K$ separation up to a few GeV/c %in the momentum range of $1.0 \\sim 2.5$ GeV/c with an efficiency greater than $90$ \\% was considered.
I. Adachi et al
Pore-structure determinations of silica aerogels by {sup 129}Xe NMR spectroscopy and imaging.
Silica aerogels represent a new class of open-pore materials with pore dimensions on a scale of tens of nanometers, and are thus classified as mesoporous materials. In this work, we show that the combination of NMR spectroscopy and chemical-shift selective magnetic resonance imaging (MRI) can resolve some of the important aspects of the structure of silica aerogels. The use of xenon as a gaseous probe in combination with spatially resolved NMR techniques is demonstrated to be a powerful, new approach for characterizing the average pore structure and steady-state spatial distributions of xenon atoms in different physicochemical environments. Furthermore, dynamic NMR magnetization transfer experiments and pulsed-field gradient (PFG) measurements have been used to characterize exchange processes and diffusive motion of xenon in samples at equilibrium. In particular, this new NMR approach offers unique information and insights into the nanoscopic pore structure and microscopic morphology of aerogels and the dynamical behavior of occluded adsorbates. MRI provides spatially resolved information on the nature of the flaw regions found in these materials. Pseudo-first-order rate constants for magnetization transfer among the bulk and occluded xenon phases indicate xenon-exchange rate constants on the order of 1 s-1 for specimens having volumes of 0.03 cm3. PFG diffusion measurements show evidence of anisotropic diffusion for xenon occluded within aerogels, with nominal self-diffusivity coefficients on the order of D= 10-3cm2/s.
Gregory, D. M.; Gerald, R. E., II; Botto, R. E.; Chemistry
High resolution transmission electron microscopy of melamine-formaldehyde aerogels and silica aerogels
The goal of the high resolution transmission electron microscopy (HRTEM) was to image the structure of two tetramethyl orthosilicate (TMOS) and two melamine-formaldehyde (MF) aerogels at the single polymer chain level{sup 1,2}. With this level of structural resolution we hoped to interrelate each aerogel's structure with its physical properties and its method of synthesis. Conventional single-step base catalysed TMOS aerogels show strings of spheroidal particles linked together with minimal necking. The spheroidal particles range from 86--132 {Angstrom} and average 113{plus minus}10 {Angstrom} in diameter{sup 2}. In contrast the TMOS aerogels reported on here were made by a two step method. After extended silica chains are grown in solution under acidic conditions with a substoichiometric amount of water, the reaction is stopped and the methanol hydrolysed from TMOS is removed. Then base catalysis and additional water are added to cause gel formation is a nonalcoholic solvent. The MF aerogels were prepared for HRTEM by fracturing them on a stereo microscope stage with razor knife so that fractured pieces with smooth flat surfaces could be selected for platinum-carbon replication. The two silica (TMOS) aerogels were both transparent and difficult to see. These aerogels were fractured on a stereo microscope stage with tweezers. 6 refs., 4 figs.
Ruben, G.C. (Dartmouth Coll., Hanover, NH (United States). Dept. of Biological Sciences)
Study on the thermal resistance in secondary particles chain of silica aerogel by molecular dynamics simulation
In this article, molecular dynamics simulation was performed to study the heat transport in secondary particles chain of silica aerogel. The two adjacent particles as the basic heat transport unit were modelled to characterize the heat transfer through the calculation of thermal resistance and vibrational density of states (VDOS). The total thermal resistance of two contact particles was predicted by non-equilibrium molecular dynamics simulations (NEMD). The defects were formed by deleting atoms in the system randomly first and performing heating and quenching process afterwards to achieve the DLCA (diffusive limited cluster-cluster aggregation) process. This kind of treatment showed a very reasonable prediction of thermal conductivity for the silica aerogels compared with the experimental values. The heat transport was great suppressed as the contact length increased or defect concentration increased. The constrain effect of heat transport was much significant when contact length fraction was in the small range (<0.5) or the defect concentration is in the high range (>0.5). Also, as the contact length increased, the role of joint thermal resistance played in the constraint of heat transport was increasing. However, the defect concentration did not affect the share of joint thermal resistance as the contact length did. VDOS of the system was calculated by numerical method to characterize the heat transport from atomic vibration view. The smaller contact length and greater defect concentration primarily affected the longitudinal acoustic modes, which ultimately influenced the heat transport between the adjacent particles.
Liu, M. [Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing100190 (China); Department of Physics, University of Chinese Academy of Sciences, Beijing 100049 (China); Qiu, L., E-mail: firstname.lastname@example.com, E-mail: firstname.lastname@example.com; Zheng, X. H., E-mail: email@example.com, E-mail: email@example.com; Zhu, J.; Tang, D. W. [Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing100190 (China)
Process Flow Chart for Immobilizing of Radioactive High Concentration Sodium Hydroxide Product from the Sodium Processing Facility at the BN-350 Nuclear power plant in Aktau, Kazakhstan
This paper describes the results of a joint research investigations carried out by the group of Kazakhstan, British and American specialists in development of a new material for immobilization of radioactive 35% sodium hydroxide solutions from the sodium coolant processing facility of the BN-350 nuclear power plant. The resulting solid matrix product, termed geo-cement stone, is capable of isolating long lived radionuclides from the environment. The physico-mechanical properties of geo-cement stone have been investigated and the flow chart for its production verified in a full scale experiments. (author)
Burkitbayev, M.; Omarova, K.; Tolebayev, T. [Ai-Farabi Kazakh National University, Chemical Faculty, Republic of Kazakhstan (Kazakhstan); Galkin, A. [KATEP Ltd., Republic of Kazakhstan (Kazakhstan); Bachilova, N. [NIISTROMPROEKT Ltd., Republic of Kazakhstan (Kazakhstan); Blynskiy, A. [Nuclear Technology Safety Centre, Republic of Kazakhstan (Kazakhstan); Maev, V. [MAEK-Kazatomprom Ltd., Republic of Kazakhstan (Kazakhstan); Wells, D. [NUKEM Limited- a member of the Freyssinet Group, Winfrith Technology Centre, Dorchester, Dorset (United Kingdom); Herrick, A. [NUKEM Limited- a member of the Freyssinet Group, Caithness (United Kingdom); Michelbacher, J. [Idaho National Laboratory, Idaho Falls (United States)
Development of a model to predict flow oscillations in low-flow sodium boiling
An experimental and analytical program has been carried out in order to better understand the cause and effect of flow oscillations in boiling sodium systems. These oscillations have been noted in previous experiments with ...
Levin, Alan Edward
EIS-0306: Treatment and Management of Sodium-Bonded Spent Nuclear Fuel
This EIS evaluates the�potential environmental impacts of the proposed electrometallurgical treatment of DOE-owned sodium bonded spent nuclear fuel in the Fuel Conditioning Facility at Argonne...
Metal corrosion in a supercritical carbon dioxide - liquid sodium power cycle.
A liquid sodium cooled fast reactor coupled to a supercritical carbon dioxide Brayton power cycle is a promising combination for the next generation nuclear power production process. For optimum efficiency, a microchannel heat exchanger, constructed by diffusion bonding, can be used for heat transfer from the liquid sodium reactor coolant to the supercritical carbon dioxide. In this work, we have reviewed the literature on corrosion of metals in liquid sodium and carbon dioxide. The main conclusions are (1) pure, dry CO{sub 2} is virtually inert but can be highly corrosive in the presence of even ppm concentrations of water, (2) carburization and decarburization are very significant mechanism for corrosion in liquid sodium especially at high temperature and the mechanism is not well understood, and (3) very little information could be located on corrosion of diffusion bonded metals. Significantly more research is needed in all of these areas.
Moore, Robert Charles; Conboy, Thomas M.
An Evaluation of the Annular Fuel and Bottle-Shaped Fuel Concepts for Sodium Fast Reactors
Two innovative fuel concepts, the internally and externally cooled annular fuel and the bottle-shaped fuel, were investigated with the goal of increasing the power density and reduce the pressure drop in the sodium-cooled ...
Memmott, Matthew
Ultracold molecules from ultracold atoms : interactions in sodium and lithium gas
The thesis presents results from experiments in which ultracold Sodium-6 and Lithium-23 atomic gases were studied near a Feshbach resonance at high magnetic fields. The enhanced interactions between atoms in the presence ...
Christensen, Caleb A
The Beta-Neutrino Correlation in Sodium-21 and Other Nuclei
RIA?INTproc?abetanu THE BETA-NEUTRINO CORRELATION IN SODIUM-electrons shaken off in beta decay. High detection ef?ciencyTOF template spectra for beta decays to 21 Ne + , are shown
Vetter, Paul A.; Abo-Shaeer, Jamil; Freedman, Stuart J.; Maruyama, Reina
Application of the Technology Neutral Framework to Sodium-�Cooled Fast Reactors
Sodium cooled fast reactors (SFRs) are considered as a novel example to exercise the Technology Neutral Framework (TNF) proposed in NUREG-1860. One reason for considering SFRs is that they have historically had a licensing ...
Johnson, Brian C.
Applying risk informed methodologies to improve the economics of sodium-cooled fast reactors
In order to support the increasing demand for clean sustainable electricity production and for nuclear waste management, the Sodium-Cooled Fast Reactor (SFR) is being developed. The main drawback has been its high capital ...
Nitta, Christopher C
Population strategies to decrease sodium intake : a global cost-effectiveness analysis
Excessive sodium consumption is both prevalent and very costly in many countries around the world. Recent research has found that more than 90% of the world's adult population live in countries with mean intakes exceeding ...
Webb, Michael William, S.M. Massachusetts Institute of Technology
Application of the technology neutral framework to sodium cooled fast reactors
Sodium cooled fast reactors (SFRs) are considered as a novel example to exercise the Technology Neutral Framework (TNF) proposed in NUREG- 1860. One reason for considering SFRs is that they have historically had a licensing ...
Johnson, Brian C. (Brian Carl)
Materials issues in high temperature ultrasonic transducers for under-sodium viewing
Liquid sodium is used as the coolant in some fast spectrum nuclear reactors. This material is optically opaque. To facilitate operations and maintenance activities, an ultrasonic under-sodium viewing system has been developed. In the USA, the technology was successfully demonstrated in the 1970s and, over the intervening 30+ years, the capability was lost. This paper reports materials challenges encountered in developing both single-element and linear phased-array 2-MHz transducers that must operate at temperatures up to 260 deg. C. The critical issues are fundamentally material selection: the ability of a transducer to be immersed into liquid sodium and function at 260 deg. C, to achieve wetting and transmission of ultrasound into the sodium, and to be able to be removed and re-used.
Bond, L. J.; Griffin, J. W.; Posakony, G. J.; Harris, R. V.; Baldwin, D. L. [Pacific Northwest National Laboratory, Richland, WA 99354 (United States)
Thermal-hydraulic analysis of innovative fuel configurations for the sodium fast reactor
The sodium fast reactor (SFR) is currently being reconsidered as an instrument for actinide management throughout the world, thanks in part to international programs such as the Generation-IV and especially the Global ...
Memmott, Matthew J
Tools for supercritical carbon dioxide cycle analysis and the cycle's applicability to sodium fast reactors
The Sodium-Cooled Fast Reactor (SFR) and the Supercritical Carbon Dioxide (S-C0?) Recompression cycle are two technologies that have the potential to impact the power generation landscape of the future. In order for their ...
Ludington, Alexander R. (Alexander Rockwell)
E-Print Network 3.0 - actual ineel sodium-bearing Sample Search...
for: actual ineel sodium-bearing Page: << < 1 2 3 4 5 > >> 1 RAC Report No. 4-CDC-Task Order 1-1999-Final FINAL REPORT Summary: Dose Reconstruction Study at the INEEL Centers for...
Sodium-Copper Exchange on Wyoming Montmorillonite in Chloride, Perchlorate, Nitrate, and Sulfate Solutions
Sodium-Copper Exchange on Wyoming Montmorillonite in Chloride, Perchlorate, Nitrate, and Sulfate. The copper exchange capacity (CuEC) and Na-Cu exchange reactions on Wyoming montmo- rillonite were studied
The role of sodium bicarbonate in the nucleation of noctilucent clouds
for the sublimation of H2O to bulk ice. A 1-dimensional model of sodium chemistry was then employed to show and particles; cloud physics and chemistry; middle atmosphere ± composition and chemistry) Introduction
Growth and bone development in weanling quarter horses fed diets supplemented with sodium zeolite-A
GROWTH AND BONE DEVELOPMENT IN WEANLING QUARTER HORSES FED DIETS SUPPLEMENTED WITH SODIUM ZEOLITE-A A Thesis by KIMBERLY SUZANNE FREY Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE December 1991 Major Subject: Nutrition GROWTH AND BONE DEVELOPMENT IN WEANLING QUARTER HORSES FED DIETS SUPPLER WITH SODIUM ZEOLITE-A A Thesis by KIMBERLY SUZPZPK FREY Approved as to style and content by...
Frey, Kimberly Suzanne
Sodium and potassium levels in the serum of acutely irradiated and non-irradiated rats
SODIUM AND POTASSIUM LEVELS IN THE SERUM OF ACUTELY IRRADIATED AND NON-IRRADIATED RATS A Thesis By DAVID PRESTON SHEPHERD Submitted to the Graduate College of the Texas ARM University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE August 1967 Major Subject: Zoology SODIUM AND POTASSIUM LEVELS IN THE SERUM OF ACUTELY IRRADIATED AND NON-IRRADIATED RATS A Thesis By DAVID PRESTON SHEPHERD Approved as to style and content by: (Chairman of Committee) (Head...
Shepherd, David Preston
Evolution of Sodium Technology R and D Actions Supporting French Liquid-Metal Fast Breeder Reactors
This paper describes the evolution of sodium technology research and development in parallel to sodium-cooled fast breeder reactor (FBR) developments in France and provides information concerning operating plants and existing projects. This paper also discusses how supporting research has adapted to the decline in FBR activities since the decommissioning of Superphenix, while capitalizing on knowledge acquired over more than four decades to be passed down to future generations.
Rodriguez, G.; Baque, F.; Astegiano, J.C. [Commissariat a l'Energie Atomique, Cadarache (France)
Characterization of the liquid sodium spray generated by a pipework hole
Due to its advantageous thermodynamic characteristics at high temperature (550 deg. C), liquid sodium is the main candidate to be the cooling fluid for Generation TV nuclear reactors SFR (Sodium-cooled Fast Reactors). Now, sodium reacts very violently, both with the water and the oxygen of the air. Only few data were known about the liquid sodium behaviour when spread in the environment through micro defects. These are often present in a cooling circuit in welded or sealed joints and more rarely in the pipes. Micro defects, on the other hand, can be also generated in a cooling circuit because of the vibrations always present in a circuit into which a fluid runs. A new set-up, named LISOF, was built for testing high temperature liquid sodium when passing through micro defects and generating sprays or jets. Sprays and jets were generated by means of nozzles embedding sub milli-metric holes the diameter of which was: 0.2 mm, 0.4 mm, 0.5 mm. Tests were performed by pressurizing liquid sodium (550 deg. C) at: 3, 6 and 9 barg. Normal and high speed cinematography were used for the direct observation of the liquid sodium sprays while Phase Doppler Interferometry was used for the measurement of the droplets characteristics and velocity. Tests concerning the behaviour of the high temperature liquid sodium firing in air or in contact with the cement cover applied to a scaled down core catcher simulacrum were also performed. The paper presents the built set-up and the collected results. (authors)
Torsello, G.; Parozzi, F.; Nericcio, L. [RSE - Nuclear and Industrial Plant Safety Team, Power Generation System Dept., via Rubattino 54, 20134 Milano (Italy); Araneo, L.; Cozzi, F. [Politecnico di Milano, Energy Dept., via Lambruschini 4, 20156 Milano (Italy); Carcassi, M.; Mattei, N. [Universita di Pisa-Facolta d'Ingegneria DIMNP-Mechanical, Nuclear and Production Dep., Largo L. Lazzarino 2, 56126 Pisa (Italy)
The tolerance of two varieties of cotton to relatively high levels of sodium and magnesium
THE TO'ERANCE OF TNO VARIETIES OF COTTON TO RELATIVELY HIGH LEVELS OF SODIUM AND MAGNESIUM A Tnesis by Msnhar C. Parekh Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree...) (Nember) (Nemb ) August 1969 ABSTRACT The Tolerance of Two Varieties of Cotton to Relatively High Levels of Sodium and Magnesium. (August 1969) Masher C. Parekh, B. S. , Gujarat University, Directed by: Dr. H. E. Joham An experiment was conducted...
Parekh, Manhar C
Solar-thermal Water Splitting Using the Sodium Manganese Oxide Process & Preliminary H2A Analysis
There are three primary reactions in the sodium manganese oxide high temperature water splitting cycle. In the first reaction, Mn2O3 is decomposed to MnO at 1,500°C and 50 psig. This reaction occurs in a high temperature solar reactor and has a heat of reaction of 173,212 J/mol. Hydrogen is produced in the next step of this cycle. This step occurs at 700°C and 1 atm in the presence of sodium hydroxide. Finally, water is added in the hydrolysis step, which removes NaOH and regenerates the original reactant, Mn2O3. The high temperature solar�?�driven step for decomposing Mn2O3 to MnO can be carried out to high conversion without major complication in an inert environment. The second step to produce H2 in the presence of sodium hydroxide is also straightforward and can be completed. The third step, the low temperature step to recover the sodium hydroxide is the most difficult. The amount of energy required to essentially distill water to recover sodium hydroxide is prohibitive and too costly. Methods must be found for lower cost recovery. This report provides information on the use of ZnO as an additive to improve the recovery of sodium hydroxide.
Todd M. Francis, Paul R. Lichty, Christopher Perkins, Melinda Tucker, Peter B. Kreider, Hans H. Funke, Allan Lewandowski, and Alan W. Weimer
Ion Recognition Approach to Volume Reduction of Alkaline Tank Waste by Separation of Sodium Salts
The purpose of this research involving collaboration between Oak Ridge National Laboratory (ORNL) and Pacific Northwest National Laboratory (PNNL) is to explore new approaches to the separation of sodium hydroxide, sodium nitrate, and other sodium salts from high-level alkaline tank waste. The principal potential benefit is a major reduction in disposed waste volume, obviating the building of expensive new waste tanks and reducing the costs of vitrification. Principles of ion recognition are being researched toward discovery of liquid-liquid extraction systems that selectively separate sodium hydroxide and sodium nitrate from other waste components. The successful concept of pseudo hydroxide extraction using fluorinated alcohols and phenols is being developed at ORNL and PNNL toward a greater understanding of the controlling equilibria, role of solvation, and of synergistic effects involving crown ethers. Synthesis efforts are being directed toward enhanced sodium binding by crown ethers, both neutral and proton-ionizable. Studies with real tank waste at PNNL will provide feedback toward solvent compositions that have promising properties.
Moyer, Bruce A.; Bonnesen, Peter V.; Custelcean, Radu; Delmau, Laetitia H.; Engle, Nancy L.; Kang, Hyun-Ah; Keever, Tamara J.; Marchand, Alan P.; Gadthula, Srinivas; Gore, Vinayak K.; Huang, Zilin; Sivappa, Rasapalli; Tirunahari, Pavan K.; Levitskaia, Tatiana G.; Lumetta, Gregg J.
An evaluation of neutralization for processing sodium-bearing liquid waste
This report addresses an alternative concept for potentially managing the sodium-bearing liquid waste generated at the Idaho Chemical Processing Plant from the current method of calcining a blend of sodium waste and high-level liquid waste. The concept is based on removing the radioactive components from sodium-bearing waste by neutralization and grouting the resulting low-level waste for on-site near-surface disposal. Solidifying the sodium waste as a remote-handled transuranic waste is not considered to be practical because of excessive costs and inability to dispose of the waste in a timely fashion. Although neutralization can remove most radioactive components to provide feed for a solidified low-level waste, and can reduce liquid inventories four to nine years more rapidly than the current practice of blending sodium-bearing liquid waste with first-cycle raffinite, the alternative will require major new facilities and will generate large volumes of low-level waste. Additional facility and operating costs are estimated to be at least $500 million above the current practice of blending and calcining. On-site, low-level waste disposal may be technically difficult and conflict which national and state policies. Therefore, it is recommended that the current practice of calcining a blend of sodium-bearing liquid waste and high-level liquid waste be continued to minimize overall cost and process complexities. 17 refs., 4 figs., 16 tabs.
Chipman, N.A.; Engelgau, G.O.; Berreth, J.R.
A Novel Low-Cost Sodium-Zinc Chloride Battery
The sodium-metal halide (ZEBRA) battery has been considered as one of the most attractive energy storage systems for stationary and transportation applications. Even though Na-NiCl2 battery has been widely investigated, there is still a need to develop a more economical system to make this technology more attractive for commercialization. In the present work, a novel low-cost Na-ZnCl2 battery with a thin planar ??-Al2O3 solid electrolyte (BASE) was proposed, and its electrochemical reactions and battery performance were investigated. Compared to the Na-NiCl2 chemistry, the ZnCl2-based chemistry was more complicated, in which multiple electrochemical reactions including liquid-phase formation occurred at temperatures above 253�C. During the first stage of charge, NaCl reacted with Zn to form Na in the anode and Na2ZnCl4 in the cathode. Once all the residual NaCl was consumed, further charging led to the formation of a NaCl-ZnCl2 liquid phase. At the end of charge, the liquid phase reacted with Zn to produce solid ZnCl2. To identify the effects of liquid-phase formation on electrochemical performance, button cells were assembled and tested at 280�C and 240�C. At 280�C where the liquid phase formed during cycling, cells revealed quite stable cyclability. On the other hand, more rapid increase in polarization was observed at 240�C where only solid-state electrochemical reactions occurred. SEM analysis indicated that the stable performance at 280�C was due to the suppressed growth of Zn and NaCl particles, which were generated from the liquid phase during discharge of each cycle.
Lu, Xiaochuan; Li, Guosheng; Kim, Jin Yong; Lemmon, John P.; Sprenkle, Vincent L.; Yang, Zhenguo
The influence of pH over topography and spectroscopic properties of silica hybrid materials embedding meso-tetratolylporphyrin
Hybrid porphyrin-silica materials consisting in 5,10,15,20-tetratolyl-21H,23H-porphine, encapsulated in silica matrices were obtained by sol-gel method. The hydrolysis and condensation reactions were performed by using tetraethylorthosilicate as precursor, either in one-step acid or in two steps acid-base catalysis, assisted or not by an ultrasonic field. The porphyrin-silica hybrid materials were monitored and characterized by AFM, FT-IR, fluorescence and UV-vis spectroscopy. As a result of porphyrin entrapping into silica gels, a general phenomenon regarding hyperchromic effects of the Q bands, occurs. UV-vis study revealed that during the sol-gel process, major changes regarding porphyrin ring structure occur, especially at acidic pH, when the dicationic species of porphyrin are formed. During acid-base catalyzed method the dye molecules tend to aggregate by {pi}-{pi} and hydrophobic co-facial interactions of sandwich H-type. In acid catalyzed process, the protonation of the porphyrins prevent the formation of aggregates, due to increased electrostatic repulsion between the molecules.
Fagadar-Cosma, Eugenia [Institute of Chemistry Timisoara of Romanian Academy, M. Viteazul Avenue, No. 24, 300223 Timisoara (Romania)], E-mail: email@example.com; Enache, Corina; Armeanu, Ileana [Institute of Chemistry Timisoara of Romanian Academy, M. Viteazul Avenue, No. 24, 300223 Timisoara (Romania); Dascalu, Dana [West University of Timisoara, Pestalozzi Street, No. 16, 300115 Timisoara (Romania); Fagadar-Cosma, Gheorghe ['Politehnica' University, T. Lalescu Street, No. 2, 300223 Timisoara (Romania); Vasile, Mihaela; Grozescu, Ioan [National Institute for Research and Development in Electrochemistry and Condensed Matter, P. Andronescu Street, No. 1, 300224 Timisoara (Romania)
Reducing Logistics Footprints and Replenishment Demands: Nano-engineered Silica Aerogels a Proven Method for Water Treatment
Rapid deployment and the use of objective force aggressively reduce logistic footprints and replenishment demands. Maneuver Sustainment requires that Future Combat Systems be equipped with water systems that are lightweight, have small footprints, and are highly adaptable to a variety of environments. Technologies employed in these settings must be able to meet these demands. Lawrence Livermore National Laboratory has designed and previously field tested nano-engineered materials for the treatment of water. These materials have been either based on silica aerogel materials or consist of composites of these aerogels with granular activated carbon (GAC). Recent tests have proven successful for the removal of contaminants including uranium, hexavalent chromium, and arsenic. Silica aerogels were evaluated for their ability to purify water that had been spiked with the nerve agent VX (O-ethyl S-(2-diisopropylaminoethyl) methylphosphonothiolate). These results demonstrated that silica aerogels were able to remove the VX from the supply water and were nearly 30 times more adsorbent than GAC. This performance could result in REDUCING CHANGEOUT FREQUENCY BY A FACTOR OF 30 or DECREASING the VOLUME of adsorbent BY A FACTOR OF 30; thereby significantly reducing logistic footprints and replenishment demands. The use of the nano-engineered Silica Aerogel/GAC composites would provide a water purification technology that meets the needs of Future Combat Systems.
Daily, W; Coleman, S; Love, A; Reynolds, J; O'Brien, K; Gammon, S
Hydrothermal Growth of Mesoporous SBA-15 Silica in the Presence of PVP-Stabilized Pt Nanoparticles: Synthesis,
Hydrothermal Growth of Mesoporous SBA-15 Silica in the Presence of PVP-Stabilized Pt Nanoparticles hydrothermal synthesis. Characterization of the Pt/SBA-15 catalysts suggests that Pt particles are located are responsible for ethane decomposition to surface carbon. The ability to design catalytic structures
RADECS 2010 Proceedings Paper LN2 1 Abstract--Radiation effects in ytterbium-doped silica optical
fibers are still poorly studied despite their importance in space- based applications as optical inter measurements. Connections between traps populated by X ray irradiations and the radiation-induced optical Stimulated Luminescence, Ytterbium-doped silica optical fibers. I. INTRODUCTION HE radiation
Atomistic simulation of the interface structure of Si nanocrystals embedded in amorphous silica Flyura Djurabekova and Kai Nordlund*
Atomistic simulation of the interface structure of Si nanocrystals embedded in amorphous silica 11 February 2008; published 14 March 2008 An efficient means to obtain light emission from a silicon in industrial wafer manufacturing lines, this has opened up a promising avenue for using low-cost silicon chips
Nordlund, Kai
Replication of butterfly wing and natural lotus leaf nanostructures by nanoimprint on Silica Sol-gel films.
1 Replication of butterfly wing and natural lotus leaf nanostructures by nanoimprint on Silica Sol these biomimetics structures over large scales and at affordable price for industrial applications as for example have chosen to imprint the lotus leaf and butterfly wings in order to obtain superhydrophobic surfaces
Preparation of Catalytic Nanoparticles in Mesoporous Silica Film for Oriented Growth of Single-Walled Carbon Nanotubes
method at the dipping rate of 2 cm/min. After the coating, the piece was dried in air at 80 o C overnight is coated on the cobalt thin film deposited by sputtering. From these investigations, it is concluded silica film should have mesopores which run through the film from the substrate to the surface. Even
Maruyama, Shigeo
Fractal Analysis of Flame-Synthesized Nanostructured Silica and Titania Powders Using Small-Angle X-ray
Fractal Analysis of Flame-Synthesized Nanostructured Silica and Titania Powders Using Small-Angle X these powders display mass-fractal morphologies, which are composed of ramified aggregates of nanoscale primary particles. Primary particle size, aggregate size, fractal dimension, and specific surface area are obtained
Beaucage, Gregory
Journal of Molecular Catalysis A: Chemical 167 (2001) 191198 The nucleation and growth of gold on silica
on silica K. Luoa, D.Y. Kimb, D.W. Goodmana, a Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, TX 77842-3012, USA b Department of Chemistry, Hallym University, Seoul, South Korea.2 monolayer equivalents were determined by TPD to be significantly lower than the sublimation energies found
Goodman, Wayne
HF-based etching processes for improving laser damage resistance of fused silica optical surfaces
The effect of various HF-based etching processes on the laser damage resistance of scratched fused silica surfaces has been investigated. Conventionally polished and subsequently scratched fused silica plates were treated by submerging in various HF-based etchants (HF or NH{sub 4}F:HF at various ratios and concentrations) under different process conditions (e.g., agitation frequencies, etch times, rinse conditions, and environmental cleanliness). Subsequently, the laser damage resistance (at 351 or 355 nm) of the treated surface was measured. The laser damage resistance was found to be strongly process dependent and scaled inversely with scratch width. The etching process was optimized to remove or prevent the presence of identified precursors (chemical impurities, fracture surfaces, and silica-based redeposit) known to lead to laser damage initiation. The redeposit precursor was reduced (and hence the damage threshold was increased) by: (1) increasing the SiF{sub 6}{sup 2-} solubility through reduction in the NH4F concentration and impurity cation impurities, and (2) improving the mass transport of reaction product (SiF{sub 6}{sup 2-}) (using high frequency ultrasonic agitation and excessive spray rinsing) away from the etched surface. A 2D finite element crack-etching and rinsing mass transport model (incorporating diffusion and advection) was used to predict reaction product concentration. The predictions are consistent with the experimentally observed process trends. The laser damage thresholds also increased with etched amount (up to {approx}30 {micro}m), which has been attributed to: (1) etching through lateral cracks where there is poor acid penetration, and (2) increasing the crack opening resulting in increased mass transport rates. With the optimized etch process, laser damage resistance increased dramatically; the average threshold fluence for damage initiation for 30 {micro}m wide scratches increased from 7 to 41 J/cm{sup 2}, and the statistical probability of damage initiation at 12 J/cm{sup 2} of an ensemble of scratches decreased from {approx}100 mm{sup -1} of scratch length to {approx}0.001 mm{sup -1}.
Suratwala, T I; Miller, P E; Bude, J D; Steele, R A; Shen, N; Monticelli, M V; Feit, M D; Laurence, T A; Norton, M A; Carr, C W; Wong, L L
Surface Complexation Model for Strontium Sorption to Amorphous Silica and Goethite
Strontium sorption to amorphous silica and goethite was measured as a function of pH and dissolved strontium and carbonate concentrations at 25 C. Strontium sorption gradually increases from 0 to 100% from pH 6 to 10 for both phases and requires multiple outer-sphere surface complexes to fit the data. All data are modeled using the triple layer model and the site-occupancy standard state; unless stated otherwise all strontium complexes are mononuclear. Strontium sorption to amorphous silica in the presence and absence of dissolved carbonate can be fit with tetradentate Sr{sup 2+} and SrOH{sup +} complexes on the {beta}-plane and a monodentate Sr{sup 2+} complex on the diffuse plane to account for strontium sorption at low ionic strength. Strontium sorption to goethite in the absence of dissolved carbonate can be fit with monodentate and tetradentate SrOH{sup +} complexes and a tetradentate binuclear Sr{sup 2+} species on the {beta}-plane. The binuclear complex is needed to account for enhanced sorption at high strontium surface loadings. In the presence of dissolved carbonate additional monodentate Sr{sup 2+} and SrOH{sup +} carbonate surface complexes on the {beta}-plane are needed to fit strontium sorption to goethite. Modeling strontium sorption as outer-sphere complexes is consistent with quantitative analysis of extended X-ray absorption fine structure (EXAFS) on selected sorption samples that show a single first shell of oxygen atoms around strontium indicating hydrated surface complexes at the amorphous silica and goethite surfaces. Strontium surface complexation equilibrium constants determined in this study combined with other alkaline earth surface complexation constants are used to recalibrate a predictive model based on Born solvation and crystal-chemistry theory. The model is accurate to about 0.7 log K units. More studies are needed to determine the dependence of alkaline earth sorption on ionic strength and dissolved carbonate and sulfate concentrations for the development of a robust surface complexation database to estimate alkaline earth sorption in the environment.
Carroll, S; Robers, S; Criscenti, L; O'Day, P
Photovoltaic's silica-rich waste sludge as supplementary cementitious material (SCM)
Waste sludge, a solid recovered from wastewater of photovoltaic-industries, composes of agglomerates of nano-particles like SiO{sub 2} and CaCO{sub 3}. This sludge deflocculates in aqueous solutions into nano-particles smaller than 1 ?m. Thus, this sludge constitutes a potentially hazardous waste when it is improperly disposed. Due to its high content of amorphous SiO{sub 2}, this sludge has a potential use as supplementary cementitious material (SCM) in concrete. In this study the main properties of three different samples of photovoltaic's silica-rich waste sludge (nSS) were physically and chemically characterized. The characterization techniques included: scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), nitrogen physical adsorption isotherm (BET method), density by Helium pycnometry, particle size distribution determined by laser light scattering (LLS) and zeta-potential measurements by dynamic light scattering (DLS). In addition, a dispersability study was performed to design stable slurries to be used as liquid additives for the concrete production on site. The effects on the hydration kinetics of cement pastes by the incorporation of nSS in the designed slurries were determined using an isothermal calorimeter. A compressive strength test of standard mortars with 7% of cement replacement was performed to determine the pozzolanic activity of the waste nano-silica sludge. Finally, the hardened system was fully characterized to determine the phase composition. The results demonstrate that the nSS can be utilized as SCM to replace portion of cement in mortars, thereby decreasing the CO{sub 2} footprint and the environmental impact of concrete. -- Highlights: �Three different samples of PV nano-silica sludge (nSS) were fully characterized. �nSS is composed of agglomerates of nano-particles like SiO{sub 2} and CaCO{sub 3}. �Dispersability studies demonstrated that nSS agglomerates are broken to nano-size. �nSS can be classified as a pozzolanic material with activity index higher than 100. �nSS can be use as a potential SCM to partly replace cement in concrete.
Quercia, G., E-mail: email@example.com [Materials innovation institute (M2i), Mekelweg 2, P.O. Box 5008, 2600 GA Delft (Netherlands); Eindhoven University of Technology, Department of the Built Environment, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Putten, J.J.G. van der [Eindhoven University of Technology, Department of the Built Environment, P.O. Box 513, 5600 MB Eindhoven (Netherlands); H�sken, G. [BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, D-12205 Berlin (Germany)] [BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, D-12205 Berlin (Germany); Brouwers, H.J.H. [Eindhoven University of Technology, Department of the Built Environment, P.O. Box 513, 5600 MB Eindhoven (Netherlands)] [Eindhoven University of Technology, Department of the Built Environment, P.O. Box 513, 5600 MB Eindhoven (Netherlands)
Preparation of polyaniline/sodium alanate hybrid using a spray-drying process
Nowadays, hydrogen is highly interesting as an energy source, in particular in the automotive field. In fact, hydrogen is attractive as a fuel because it prevents air pollution and greenhouse emissions. One of the main problems with the utilization of hydrogen as a fuel is its on-board storage. The purpouse of this work was to develop a new hybrid material consisting of a polyaniline matrix with sodium alanate (NaAlH{sub 4}) using a spray-drying process. The polyaniline used for this experiment was synthesized by following a well-established method for the synthesis of the emeraldine base form of polyaniline using dodecylbenzenesulfonic acid as dopant. Micro particles of polyaniline/sodium alanate hybrids with 30 and 50 wt% of sodium alanate were prepared by using a spray-drying technique. Dilute solutions of polyaniline/sodium alanate were first prepared, 10g of the solid materials were mixed with 350 ml of toluene under stirring at room temperature for 24h and the solutions were dried using spray-dryer (B�chi, Switzerland) with 115�C of an inlet temperature. The hybrids were analyzed by differential scanning calorimetry, FT-IR and scanning electron microscopy (SEM). The addition of sodium alanate decreased the glass transition temperature of the hybrids when compared to neat polyaniline. FT-IR spectrum analysis was performed to identify the bonding environment of the synthesized material and was observed that simply physically mixture occurred between polyaniline and sodium alanate. The SEM images of the hybrids showed the formation of microspheres with sodium alanate dispersed in the polymer matrix.
Moreira, B. R., E-mail: firstname.lastname@example.com, E-mail: email@example.com, E-mail: email@example.com; Passador, F. R., E-mail: email@example.com, E-mail: firstname.lastname@example.com, E-mail: firstname.lastname@example.com; Pessan, L. A., E-mail: email@example.com, E-mail: email@example.com, E-mail: email@example.com [Dep. de Engenharia de Materiais, Federal University of S�o Carlos (Brazil)
In this project, now completing its third year of its second renewal period, a collaborative project involving Oak Ridge National Laboratory, Pacific Northwest National Laboratory, and the University of North Texas has been addressing outstanding questions regarding the separation of the bulk sodium constituents of alkaline tank waste. The principal potential benefit of this research is a major reduction in the volume of radioactive tank waste, obviating the building of expensive new tanks and reducing the costs of vitrification. As a general approach, principles of ion recognition are being explored toward discovery and basic understanding of liquid-liquid extraction systems that selectively separate sodium hydroxide and sodium salts from waste-like matrices. Questions being addressed pertain to applicable extraction equilibria and how extraction properties relate to extractant structure. Progress has included the elucidation of the promising concept of pseudo hydroxide extraction (PHE), demonstration of crown-ether synergized PHE, demonstration of combined sodium hydroxide/sodium nitrate separation, and synthesis of novel ditopic receptors for ditopic PHE. In future efforts (pending renewal), a thermochemical study of PHE relating extractant acidity to extraction strength is proposed, and this study will be extended to systems containing crown ethers, including proton-ionizable ones. A series of crown ethers will be synthesized for this purpose and to investigate the extraction of bulk sodium salts (e.g., nitrate, nitrite, and sulfate), possibly in combination with sodium hydroxide. Simple proof-of-principle tests with real tank waste at PNNL will provide feedback toward solvent designs that have desirable properties. In view of the upcoming milestone of completion of the second renewal period, this report will, in addition to providing a summary of the past year's progress, summarize all of the work completed since the start of this project.
Moyer, Bruce A.; Marchand, Alan P.; Lumetta, Gregg J.
Sustained Recycle in Light Water and Sodium-Cooled Reactors
From a physics standpoint, it is feasible to sustain recycle of used fuel in either thermal or fast reactors. This paper examines multi-recycle potential performance by considering three recycling approaches and calculating several fuel cycle parameters, including heat, gamma, and neutron emission of fresh fuel; radiotoxicity of waste; and uranium utilization. The first recycle approach is homogeneous mixed oxide (MOX) fuel assemblies in a light water reactor (LWR). The transuranic portion of the MOX was varied among Pu, NpPu, NpPuAm, or all-TRU. (All-TRU means all isotopes through Cf-252.) The Pu case was allowed to go to 10% Pu in fresh fuel, but when the minor actinides were included, the transuranic enrichment was kept below 8% to satisfy the expected void reactivity constraint. The uranium portion of the MOX was enriched uranium. That enrichment was increased (to as much as 6.5%) to keep the fuel critical for a typical LWR irradiation. The second approach uses heterogeneous inert matrix fuel (IMF) assemblies in an LWR - a mix of IMF and traditional UOX pins. The uranium-free IMF fuel pins were Pu, NpPu, NpPuAm, or all-TRU. The UOX pins were limited to 4.95% U-235 enrichment. The number of IMF pins was set so that the amount of TRU in discharged fuel from recycle N (from both IMF and UOX pins) was made into the new IMF pins for recycle N+1. Up to 60 of the 264 pins in a fuel assembly were IMF. The assembly-average TRU content was 1-6%. The third approach uses fast reactor oxide fuel in a sodium-cooled fast reactor with transuranic conversion ratio of 0.50 and 1.00. The transuranic conversion ratio is the production of transuranics divided by destruction of transuranics. The FR at CR=0.50 is similar to the CR for the MOX case. The fast reactor cases had a transuranic content of 33-38%, higher than IMF or MOX.
Steven J. Piet; Samuel E. Bays; Michael A. Pope; Gilles J. Youinou
Adsorption and methanation of carbon dioxide on a nickel/silica catalyst
Temperature-programed desorption and reaction studies showed that increasing amounts of CO/sub 2/ adsorbed on silica-supported 6.9% nickel with increasing temperature to a maximum adsorption at approx. 443/sup 0/K, i.e., that the adsorption was activated; that CO/sub 2/ desorbed partly as CO/sub 2/ with the peak at 543/sup 0/K, and partly as CO with several peaks; that in the presence of hydrogen, nearly all adsorbed CO/sub 2/ desorbed as methane, and a small amount as CO; and that the methane desorption peaks from adsorbed CO and CO/sub 2/ both occurred at 473/sup 0/K. These results suggested that carbon dioxide adsorbed dissociatively as a carbon monoxide and an oxygen species. An observed absence of higher hydrocarbons in the methanation products of carbon dioxide was attributed to a high hydrogen/carbon monoxide surface ratio caused by the activated carbon dioxide adsorption.
Falconer, J.L.; Zagli, A.E.
Reduction of damage initiation density in fused silica optics via UV laser conditioning
The present invention provides a method for reducing the density of sites on the surface of fused silica optics that are prone to the initiation of laser-induced damage, resulting in optics which have far fewer catastrophic defects and are better capable of resisting optical deterioration upon exposure for a long period of time to a high-power laser beam having a wavelength of about 360 nm or less. The initiation of laser-induced damage is reduced by conditioning the optic at low fluences below levels that normally lead to catastrophic growth of damage. When the optic is then irradiated at its high fluence design limit, the concentration of catastrophic damage sites that form on the surface of the optic is greatly reduced.
Peterson, John E.; Maricle, Stephen M.; Brusasco, Raymond M.; Penetrante, Bernardino M.
A neutron scattering technique was developed to measure the density of heavy water confined in a nanoporous silica matrix in a temperature-pressure range, from 300 to 130 K and from 1 to 2,900 bars, where bulk water will crystalize. We observed a prominent hysteresis phenomenon in the measured density profiles between warming and cooling scans above 1,000 bars. We inter- pret this hysteresis phenomenon as support (although not a proof) of the hypothetical existence of a first-order liquid liquid phase transition of water that would exist in the macroscopic system if crystallization could be avoided in the relevant phase region. Moreover, the density data we obtained for the confined heavy water under these conditions are valuable to large communities in biology and earth and planetary sciences interested in phenomena in which nanometer-sized water layers are involved.
Zhang, Yang [ORNL; Faraone, Antonio [National Institute of Standards and Technology (NIST); Kamitakahara, William [ORNL; Liu, Kao-Hsiang [National Taiwan University; Mou, Chung-Yuan [National Taiwan University; Leao, Juscelino B [ORNL; Chang, Sung C [ORNL; Chen, Sow-hsin H [ORNL
A molecular dynamics investigation of the unusual concentration dependencies of Fick diffusivities in silica mesopores
Molecular Dynamics (MD) simulations were carried out to determine the self-diffusivitiy, D{sub i,self}, the Maxwell�Stefan diffusivity, �{sub i}, and the Fick diffusivity, D{sub i}, for methane (C1), ethane (C2), propane (C3), n-butane (nC4), n-pentane (nC5), n-hexane (nC6), n-heptane (nC7), and cyclohexane (cC6) in cylindrical silica mesopores for a range of pore concentrations. The MD simulations show that zero-loading diffusivity �{sub i}(0) is consistently lower, by up to a factor of 20, than the values anticipated by the classical Knudsen formula. The concentration dependence of the Fick diffusivity, D{sub i} is found to be unusually complex, and displays a strong minimum in some cases; this characteristic can be traced to molecular clustering.
Krishna, Rajamani; van Baten, Jasper M
X-ray radiographic technique for measuring density uniformity of silica aerogel
This paper proposes a new X-ray radiographic technique for measuring density uniformity of silica aerogels used as radiator in proximity-focusing ring-imaging Cherenkov detectors. To obtain high performance in a large-area detector, a key characteristic of radiator is the density (i.e. refractive index) uniformity of an individual aerogel monolith. At a refractive index of n = 1.05, our requirement for the refractive index uniformity in the transverse plane direction of an aerogel tile is |\\delta (n - 1)/(n - 1)| aerogels from a trial production and that of Panasonic products (SP-50) as a reference, and to confirm they have sufficient density uniformity within \\pm 1% along the transverse plane direction. The measurement results show that the proposed technique can quantitatively estimate the density uniformity of aerogels.
Makoto Tabata; Yoshikiyo Hatakeyama; Ichiro Adachi; Takeshi Morita; Keiko Nishikawa
Tanpopo cosmic dust collector: Silica aerogel production and bacterial DNA contamination analysis
Hydrophobic silica aerogels with ultra-low densities have been designed and developed as cosmic dust capture media for the Tanpopo mission which is proposed to be carried out on the International Space Station. Glass particles as a simulated cosmic dust with 30 \\mu m in diameter and 2.4 g/cm^3 in density were successfully captured by the novel aerogel at a velocity of 6 km/s. Background levels of contaminated DNA in the ultra-low density aerogel were lower than the detection limit of a polymerase chain reaction assay. These results show that the manufactured aerogel has good performance as a cosmic dust collector and sufficient quality in respect of DNA contamination. The aerogel is feasible for the biological analyses of captured cosmic dust particles in the astrobiological studies.
Tabata, Makoto; Yokobori, Shin-ichi; Kawai, Hideyuki; Takahashi, Jun-ichi; Yano, Hajime; Yamagishi, Akihiko
Development of transparent silica aerogel over a wide range of densities
We have succeeded in developing hydrophobic silica aerogels over a wide range of densities (i.e. refractive indices). A pinhole drying method was invented to make possible producing highly transparent aerogels with entirely new region of refractive indices of 1.06-1.26. Obtained aerogels are more transparent than conventional ones, and the refractive index is well controlled in the pinhole drying process. A test beam experiment was carried out in order to evaluate the performance of the pinhole-dried aerogels as a Cherenkov radiator. A clear Cherenkov ring was successfully observed by a ring imaging Cherenkov counter. We also developed monolithic and hydrophobic aerogels with a density of 0.01 g/cm^3 (a low refractive index of 1.0026) as a cosmic dust capturer for the first time. Consequently, aerogels with any refractive indices between 1.0026 and 1.26 can be produced freely.
Tabata, Makoto; Ishii, Yoshikazu; Kawai, Hideyuki; Sumiyoshi, Takayuki; Yokogawa, Hiroshi; 10.1016/j.nima.2010.02.241
Makoto Tabata; Ichiro Adachi; Yoshikazu Ishii; Hideyuki Kawai; Takayuki Sumiyoshi; Hiroshi Yokogawa
Tabata, Makoto; Adachi, Ichiro; Morita, Takeshi; Nishikawa, Keiko; 10.1016/j.nima.2012.09.001
Liquid�solid phase transition of hydrogen and deuterium in silica aerogel
Behavior of hydrogen isotopes confined in disordered low-density nanoporous solids remains essentially unknown. Here, we use relaxation calorimetry to study freezing and melting of H{sub 2} and D{sub 2} in an ?85%-porous base-catalyzed silica aerogel. We find that liquid�solid transition temperatures of both isotopes inside the aerogel are depressed. The phase transition takes place over a wide temperature range of ?4?K and non-trivially depends on the liquid filling fraction, reflecting the broad pore size distribution in the aerogel. Undercooling is observed for both H{sub 2} and D{sub 2} confined inside the aerogel monolith. Results for H{sub 2} and D{sub 2} are extrapolated to tritium-containing hydrogens with the quantum law of corresponding states.
Van Cleve, E.; Worsley, M. A.; Kucheyev, S. O., E-mail: email@example.com [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)
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 dependent on the catalyst concentration. After supercritical extraction, the aerogels are transparent, uncracked tiles with densities as low as .003 g/cc. 6 figs., 11 refs.
Tillotson, T.M.; Hrubesh, L.W.
Post-Harvest Processing Methods for Reduction of Silica and Alkali Metals in Wheat Straw
Silica and alkali metals in wheat straw limit its use for bioenergy and gasification. Slag deposits occur via the eutectic melting of SiO2 with K2O, trapping chlorides at surfaces and causing corrosion. A minimum melting point of 950�C is desirable, corresponding to SiO2:K2O of about 3:1. Mild chemical treatments were used to reduce Si, K, and Cl, while varying temperature, concentration, %-solids, and time. Dilute acid was more effective at removing K and Cl, while dilute alkali was more effective for Si. Reduction of minerals in this manner may prove economical for increasing utilization of the straw for combustion or gasification.
Thompson, David Neal; Lacey, Jeffrey Alan; Shaw, Peter Gordon
Phototransformation of Polycyclic Aromatic Hydrocarbons (PAHs) on a Non-Semi Conductive Surface Such as Silica
Polycyclic aromatic hydrocarbons (PAH), by products of fossil fuel production and consumption, constitute a large class of environmental pollutants. These toxic and sometimes carcinogenic compounds are also found in coal tar and fly ash. When released into the air, they can be sorbed onto particulates present in the atmosphere where they find their way into soil and ground water upon being washed by rain. During their residence time in the environment, PAHs will be exposed to solar radiation and may undergo phototransformation to other products. Thus, light induced photodegradation of PM`s at the solid/air interfaces can play a significant role in their depletion. Light-induced processes have been claimed to enhance transformation of these PM`s in the environment. However, detailed studies on the nature and identities of photoproducts formed during the transformation of these compounds on solid surfaces is scarce. Since insulators such as silica, alumina,silicoaluminates and calcium carbonate are believed to constitute up 20-30% of inorganic particulates present in the atmosphere, they serve as environmentally relevant model surfaces to study the photophysical and photochemical behavior of PM`s. Although photochemistry of organic compounds adsorbed on solid surfaces has received much attention in recent years, the specific properties of the interface which influence photoprocesses and the exact mechanism of interaction between a surface and a substrate are often not well understood. We have investigated the photochemistry of many PAHs including eight that are on Environmental Protection Agency`s (EPA) sixteen priority pollutant PAH list shown in Table 1 at silica/air interface.
Dabestani, R., Sigman, M.E.
Combined Utilization of Cation Exchanger and Neutral Receptor to Volume Reduction of Alkaline Tank Waste by Separation of Sodium Salts
In this report, novel approaches to the selective liquid-liquid extraction separation of sodium hydroxide and sodium nitrate from high-level alkaline tank waste will be discussed. Sodium hydroxide can be successfully separated from alkaline tank-waste supernatants by weakly acidic lipophilic hydroxy compounds via a cation-exchange mechanism referred to as pseudo hydroxide extraction. In a multi-cycle process, as sodium hydroxide in the aqueous phase becomes depleted, it is helpful to have a neutral sodium receptor in the extraction system to exploit the high nitrate concentration in the waste solution to promote sodium removal by an ion-pair extraction process. Simultaneous utilization of an ionizable organic hydroxy compound and a neutral extractant (crown ether) in an organic phase results in the synergistic enhancement of ion exchange and improved separation selectivity due to the receptor's strong and selective sodium binding. Moreover, combination of the hydroxy compound and the crown ether provides for mutually increased solubility, even in a non-polar organic solvent. Accordingly, application of Isopar{reg_sign} L, a kerosene-like alkane solvent, becomes feasible. This investigation involves examination of such dual-mechanism extraction phases for sodium extraction from simulated and actual salt cake waste solutions. Sodium salts can be regenerated upon the contact of the loaded extraction phases with water. Finally, conditions of potential extraction/strip cycling will be discussed.
Levitskaia, Tatiana G.; Lumetta, Gregg J.; Moyer, Bruce A.
Two-dimensional computational modeling of sodium boiling in simulated LMFBR fuel-pin bundles
Extensive sodium boiling tests have been carried out in two simulated LMFBR fuel pin bundles in the Thermal-Hydraulic Out-of-Reactor Safety (THORS) Facility at Oak Ridge National Laboratory. Experimental results from a 19-pin bundle (THORS Bundle 6A) have been previously reported, and experimental results from a 61-pin bundle (THORS Bundle 9) will be reported soon. The results discussed here are from the 19-pin bundle. Preliminary analysis has shown that the computational methods used and conclusions reached are equally valid for the 61-pin bundle, as well as the 19-pin in-reactor Sodium Loop Safety Facility (SLSF) W-1 experiment. The main result of THORS sodium boiling experimentation is that boiling behavior is determined by two-dimensional effects, i.e., the rates of mass, momentum and energy transfer in the direction perpendicular to the axes of the fuel pins.
Dearing, J.F.
Development and application of modeling tools for sodium fast reactor inspection
To support the development of in-service inspection methods for the Advanced Sodium Test Reactor for Industrial Demonstration (ASTRID) project led by the French Atomic Energy Commission (CEA), several tools that allow situations specific to Sodium cooled Fast Reactors (SFR) to be modeled have been implemented in the CIVA software and exploited. This paper details specific applications and results obtained. For instance, a new specular reflection model allows the calculation of complex echoes from scattering structures inside the reactor vessel. EMAT transducer simulation models have been implemented to develop new transducers for sodium visualization and imaging. Guided wave analysis tools have been developed to permit defect detection in the vessel shell. Application examples and comparisons with experimental data are presented.
Le Bourdais, Florian; Marchand, Beno�t; Baronian, Vahan [CEA LIST, Centre de Saclay F-91191 Gif-sur-Yvette (France)
Hemodynamic characterization of chronic bile duct-ligated rats: effect of pentobarbital sodium
Systemic and splanchnic hemodynamics of the chronic bile duct-ligated rat were characterized by radioactive microspheres. Conscious and pentobarbital sodium-anesthetized, bile duct-ligated and sham-operated rats had cardiac output and regional organ blood flows determined. The conscious bile duct-ligated rat compared with the sham-operated showed a hyperdynamic circulation with an increased cardiac output and portal tributary blood flow. Pentobarbital sodium anesthesia induced marked hemodynamic changes in both sham-operated and bile duct-ligated rats. The latter group was especially sensitive to its effects; thus, comparison of cardiac output and portal tributary blood flow between anesthetized bile duct-ligated and sham-operated rats showed no significant differences. The authors conclude that the rat with cirrhosis due to chronic bile duct ligation is an excellent model for hemodynamic investigations but should be studied in the conscious state, since pentobarbital sodium anesthesia eliminated the hyperdynamic circulation.
Lee, S.S.; Girod, C.; Braillon, A.; Hadengue, A.; Lebrec, D.
GIF sodium fast reactor project R and D on safety and operation
The 'Safety and Operation' project is started in 2009 within the framework of Generation-IV International Forum (GIF) Sodium Fast Reactor (SFR) research and development program. In the safety area, the project involves R and D activities on phenomenological model development and experimental programs, conceptual studies in support of the design of safety provisions, preliminary assessment of safety systems, framework and methods for analysis of safety architecture. In the operation area, the project involves R and D activities on fast reactors safety tests and analysis of reactor operations, feedback from decommissioning, in-service inspection technique development, under-sodium viewing and sodium chemistry. This paper presents a summary of such activities and the main achievements. (authors)
Vasile, A.; Sofu, T.; Jeong, H. Y.; Sakai, T. [CEA DEN Cadarache, DER, 13108 Saint-Paul-Lez-Durance (France)
Design and development of a high-temperature sodium compatibility testing facility
The use of advanced alloys within sodium-cooled fast reactors (SFRs) has been identified as a means of increasing plant efficiency and reducing construction costs. In particular, alloys such as NF-616, NF-709 and HT-UPS are promising because they exhibit greater strength than traditional structural materials such as 316-SS. However, almost nothing is known about the sodium compatibility of these new alloys. Therefore, research taking place at the Univ. of Wisconsin-Madison is focused on studying the effects of sodium corrosion on these materials under prototypic SFR operating conditions (600 [ deg. C], V Na=10 [m/s], C 0{approx} 1 [wppm]). This paper focuses on the design and construction of the testing facility with an emphasis on moving magnet pumps (MMPs). Corrosion data from a preliminary 500 [hr] natural convection test will also be presented. (authors)
Hvasta, M. G.; Nolet, B. K.; Anderson, M. H. [Univ. of Wisconsin-Madison, 1500 Engineering Dr., Madison - ERB 841, WI 53705 (United States)
Draft Environmental Impact Statement for the Treatment and Management of Sodium-Bonded Spent Nuclear Fuel
This document summarizes the U.S. Department of Energy's ''Draft Environmental Impact Statement for the Treatment and Management of Sodium-Bonded Spent Nuclear Fuel''. In addition to information concerning the background, purpose and need for the proposed action, and the National Environmental Policy Act process, this summary describes the characteristics of sodium-bonded spent nuclear fuel, the proposed treatment methods, the proposed facilities, the alternatives considered, and the environmental consequences of these alternatives. A glossary is included at the end to assist the reader with some of the technical terms used in this document.
Galvanic corrosion of structural aluminum coupled with mild steel in a dilute sodium dichromate electrolyte
GALVANIC COP?'SION OF STRUCTURAL ALI'I'lINUl'I COUPLED WITH MILD STEEL IN A OILLrl'E SODIUM DICHPOliATE FLECTROLY'I E A Tl. esi, ROBERT FRANKLIN FORD, JR. Submitted to the Graduate Co11ege of Texas AEM University in Partia1 fuifiilment.... Approved as to style and content by: + ~J Co-Chairman of Commii:t C Co-Chair n of Committe~e Member+ I Head of D=p rtm t) Januar; IDIO ABSTRACT Calvanic Corrosion of Structural Aluminum Coup'led with Mild Steel in a Dilute Sodium Dichromate...
Ford, Robert Franklin
Method of making a current collector for a sodium/sulfur battery
This specification is directed to a method of making a current collector for a sodium/sulfur battery. The current collector so-made is electronically conductive and resistant to corrosive attack by sulfur/polysulfide melts. The method includes the step of forming the current collector for the sodium/sulfur battery from a composite material formed of aluminum filled with electronically conductive fibers selected from the group of fibers consisting essentially of graphite fibers having a diameter up to 10 microns and silicon carbide fibers having a diameter in a range of 500--1,000 angstroms. 2 figs.
Tischer, R.P.; Winterbottom, W.L.; Wroblowa, H.S.
This specification is directed to a method of making a current collector (14) for a sodium/sulfur battery (10). The current collector so-made is electronically conductive and resistant to corrosive attack by sulfur/polysulfide melts. The method includes the step of forming the current collector for the sodium/sulfur battery from a composite material (16) formed of aluminum filled with electronically conductive fibers selected from the group of fibers consisting essentially of graphite fibers having a diameter up to 10 microns and silicon carbide fibers having a diameter in a range of 500-1000 angstroms.
Tischer, Ragnar P. (Birmingham, MI); Winterbottom, Walter L. (Farmington Hills, MI); Wroblowa, Halina S. (West Bloomfield, MI)
Preliminary analysis of patent trends for sodium/sulfur battery technology
This document summarizes development trends in sodium/sulfur battery technology based on data from US patents. Purpose of the study was to use the activity, timing and ownership of 285 US patents to identify and describe broad patterns of change in sodium/sulfur battery technology. The analysis was conducted using newly developed statistical and computer graphic techniques for describing technology development trends from patent data. This analysis suggests that for some technologies trends in patent data provide useful information for public and private R and D planning.
Triplett, M.B.; Winter, C.; Ashton, W.B.
Robust conductive mesoporous carbon?silica composite films with highly ordered and oriented orthorhombic structures from triblock-copolymer template co-assembly
In this work, we describe a facile approach to improve the robustness of conductive mesoporous carbon-based thin films by the addition of silica to the matrix through the triconstituent organic-inorganic-organic co-assembly of resol (carbon precursor) and tetraethylorthosilicate (silica precursor) with triblock-copolymer Pluronic F127. The pyrolysis of the resol-silica-pluronic F127 film yields a porous composite thin film with well-defined mesostructure. X-Ray diffraction (XRD), grazing incidence small angle X-ray scattering (GISAXS), and electron microscopy measurements indicate that the obtained carbon-based thin films have a highly ordered orthorhombic mesostructure (Fmmm) with uniform large pore size ({approx}3 nm). The orthorhombic mesostructure is oriented and the (010) plane is parallel to the silicon wafer substrate. The addition of silica to the matrix impacts the pore size, surface area, porosity, modulus and conductivity. For composite films with approximately 40 wt% silica, the conductivity is decreased by approximately an order of magnitude in comparison to a pure carbon mesoporous film, but the conductivity is comparable to typical printed carbon inks used in electrochemical sensing, {approx}10 S cm{sup -1}. The mechanical properties of these mesoporous silica-carbon hybrid films are similar to the pure carbon analogs with a Young's modulus between 10 GPa and 15 GPa, but the material is significantly more porous. Moreover, the addition of silica to the matrix appears to improve the adhesion of the mesoporous film to a silicon wafer. These mesoporous silica-carbon composite films have appropriate characteristics for use in sensing applications.
Song, Lingyan; Feng, Dan; Campbell, Casey G.; Gu, Dong; Forster, Aaron M.; Yager, Kevin G.; Fredin, Nathaniel; Lee, Hae-Jeong; Jones, Ronald L.; Zhao, Dongyuan; Vogt, Bryan D. (AZU)
Simplified modeling of liquid sodium medium with temperature and velocity gradient using real thermal-hydraulic data. Application to ultrasonic thermometry in sodium fast reactor
In the framework of the French R and D program for the Generation IV reactors and specifically for the sodium cooled fast reactors (SFR), studies are carried out on innovative instrumentation methods in order to improve safety and to simplify the monitoring of fundamental physical parameters during reactor operation. The aim of the present work is to develop an acoustic thermometry method to follow up the sodium temperature at the outlet of subassemblies. The medium is a turbulent flow of liquid sodium at 550 Degree-Sign C with temperature inhomogeneities. To understand the effect of disturbance created by this medium, numerical simulations are proposed. A ray tracing code has been developed with Matlab Copyright-Sign in order to predict acoustic paths in this medium. This complex medium is accurately described by thermal-hydraulic data which are issued from a simulation of a real experiment in Japan. The analysis of these results allows understanding the effects of medium inhomogeneities on the further thermometric acoustic measurement.
Massacret, N.; Jeannot, J. P. [DEN/DTN/STPA/LIET, CEA Cadarache, Saint Paul Lez Durance (France); Moysan, J.; Ploix, M. A.; Corneloup, G. [Aix-Marseille Univ, LMA UPR 7051 CNRS, site LCND, 13625 Aix-en-Provence (France)
Silane Modification of Glass and Silica Surfaces to Obtain Equally Oil-Wet Surfaces in Glass-Covered Silicon Micromodel Applications
The wettability of silicon and glass surfaces can be modified by silanization. However, similar treatments of glass and silica surfaces using the same silane do not necessarily yield the same wettability as determined by the oil-water contact angle. In this technical note, surface cleaning pretreatments were investigated to determine conditions that would yield oil-wet surfaces on glass with similar wettability to silica surfaces treated with the same silane, and both air-water and oil-water contact angles were determined. Air-water contact angles were less sensitive to differences between silanized silica and glass surfaces, often yielding similar values while the oil-water contact angles were quite different. Borosilicate glass surfaces cleaned with standard cleaning solution 1 (SC1) yield intermediate-wet surfaces when silanized with hexamethyldisilazane, while the same cleaning and silanization yields oil-wet surfaces on silica. However, cleaning glass in boiling concentrated nitric acid creates a surface that can be silanized to obtain oil-wet surfaces using HDMS. Moreover, this method is effective on glass with prior thermal treatment at an elevated temperature of 400oC. In this way, silica and glass can be silanized to obtain equally oil-wet surfaces using HMDS. It is demonstrated that pretreatment and silanization is feasible in silicon-silica/glass micromodels previously assembled by anodic bonding, and that the change in wettability has a significant observable effect on immiscisble fluid displacements in the pore network.
Grate, Jay W.; Warner, Marvin G.; Pittman, Jonathan W.; Dehoff, Karl J.; Wietsma, Thomas W.; Zhang, Changyong; Oostrom, Martinus
In steam reforming reactions (SRRs) of alkanes and alcohols to produce H{sub 2}, noble metals such as platinum (Pt) and palladium (Pd) are extensively used as catalyst. These metals are expensive; so, to reduce noble-metal loading, bi-metallic nanocatalysts containing non-noble metals in MCM-41 (Mobil Composition of Material No. 41, a mesoporous material) as a support material with high-surface area were synthesized using one-pot hydrothermal procedure with a surfactant such as cetyltrimethylammonium bromide (CTAB) as a template. Bi-metallic nanocatalysts of Pd-Ni and Pd-Co with varying metal loadings in MCM-41 were characterized by x-ray diffraction (XRD), N{sub 2} adsorption, and Transmission electron microscopy (TEM) techniques. The BET surface area of MCM-41 (~1000 m{sup 2}/g) containing metal nanoparticles decreases with the increase in metal loading. The FTIR studies confirm strong interaction between Si-O-M (M = Pd, Ni, Co) units and successful inclusion of metal into the mesoporous silica matrix. The catalyst activities were examined in steam reforming of methanol (SRM) reactions to produce hydrogen. Reference tests using catalysts containing individual metals (Pd, Ni and Co) were also performed to investigate the effect of the bimetallic system on the catalytic behavior in the SRM reactions. The bimetallic system remarkably improves the hydrogen selectivity, methanol conversion and stability of the catalyst. The results are consistent with a synergistic behavior for the Pd-Ni-bimetallic system. The performance, durability and thermal stability of the Pd-Ni/MCM-41 and Pd-Co/MCM-41 suggest that these materials may be promising catalysts for hydrogen production from biofuels. A part of this work for synthesis and characterization of Pd-Ni-MCM-41 and its activity for SRM reactions has been published (�Development of Mesoporous Silica Encapsulated Pd-Ni Nanocatalyst for Hydrogen Production� in �Production and Purification of Ultraclean Transportation Fuels�; Hu, Y., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2011.)
Kuila, Debasish; Ilias, Shamsuddin
Sodium Cooled Fast Reactors and the Pyro-Process: Conversion of Nuclear Waste into a Fuel Source
1 Sodium Cooled Fast Reactors and the Pyro-Process: Conversion of Nuclear Waste into a Fuel Source. Belanger Chair, Department of Physics #12;2 Abstract A review of the sodium cooled fast reactor........................................................................................23 1.3.5 Reactor Startup
Belanger, David P.
Structure and hydrogen dynamics of pure and Ti-doped sodium alanate Jorge iguez,1,2
Structure and hydrogen dynamics of pure and Ti-doped sodium alanate Jorge ��iguez,1,2 T. Yildirim,1, Honolulu, Hawaii 96822, USA (Received 2 June 2004; published 3 August 2004) We have studied the structure, energetics, and dynamics of pure and Ti-doped sodium alanate NaAlH4 , focusing on the possibility
Yildirim, Taner
The feasibility of meeting the World Health Organization guidelines for sodium and potassium: a cross-national comparison study
and meat/poultry mixed dishes, are among the most important sources of dietary sodium in the US.31 32 Processed foods, including breads, cereals and grains contribute a majority of sodium in the United Kingdom, and France as well.12 33 It is important...
Drewnowski, Adam; Rehm, Colin D.; Maillot, Matthieu; Mendoza, Alfonso; Monsivais, Pablo
Nature and distribution of iron sites in a sodium silicate glass investigated by neutron diffraction and EPSR simulation
1 Nature and distribution of iron sites in a sodium silicate glass investigated by neutron distributed in the silicate network and shares corner with silicate tetrahedra. The existence of a majority, such as the increase of the elastic modulus of sodium silicate glasses with increasing Fe-concentration. Our data
Differences in pulmonary responses of rats, other animals, and humans to chronic inhalation of silica and other particles
The pulmonary carcinogenicity of quartz in rats supports the plausibility of silica-induced lung cancer in humans. However, pulmonary responses of rats to dusts differ from those of other rodents, and may differ from those of humans. Dust-exposed rats have a greater propensity than mice or hamsters for epithelial hyperplasia, metaplasia, and fibrosis. Lung tumors occur in rats, but not mice or hamsters, treated with quartz, or exposed chronically to several other dusts. There are few opportunities for directly comparing the susceptibilities of rats and humans to dust-induced lung tumors. Because of the uncertain human responses to silica and many other particles, the negative human lung cancer response to coal dust may provide the best opportunity to calibrate responses of rats against those of humans. Historical dust lung burdens in coal miners were in the range of those associated with carcinogenicity in rats exposed to several dusts, but the carcinogenicity of coal dust in rats is unknown. The usefulness of tumor data from rats for predicting human lung cancer risk from inhaled silica and other dusts remains uncertain.
Mauderly, J.L.
Simultaneous measurement of the surface temperature and the release of atomic sodium from a burning black liquor droplet
Simultaneous measurement of the concentration of released atomic sodium, swelling, surface and internal temperature of a burning black liquor droplet under a fuel lean and rich condition has been demonstrated. Two-dimensional two-colour optical pyrometry was employed to determine the distribution of surface temperature and swelling of a burning black liquor droplet while planar laser-induced fluorescence (PLIF) was used to assess the temporal release of atomic sodium. The key findings of these studies are: (i) the concentration of atomic sodium released during the drying and devolatilisation stages was found to be correlated with the external surface area; and (ii) the insignificant presence of atomic sodium during the char consumption stage shows that sodium release is suppressed by the lower temperature and by the high CO{sub 2} content in and around the particle. (author)
Saw, Woei L.; Nathan, Graham J. [Centre for Energy Technology, The University of Adelaide, SA 5006 (Australia); School of Mechanical Engineering, The University of Adelaide (Australia); Ashman, Peter J.; Alwahabi, Zeyad T. [Centre for Energy Technology, The University of Adelaide, SA 5006 (Australia); School of Chemical Engineering, The University of Adelaide (Australia); Hupa, Mikko [Process Chemistry Centre, Aabo Akademi, Biskopsgatan 8 FI-20500 Aabo (Finland)
Sodium shortage as a constraint on the carbon cycle in an inland tropical rainforest
Sodium shortage as a constraint on the carbon cycle in an inland tropical rainforest Michael- composition of pure cellulose by up to 50%, compared with stream water alone. These effects emerged after 134). We provide experimental evidence that Na shortage slows the carbon cycle. Because 80% of global
Kaspari, Mike
Advanced Materials for Sodium-Beta Alumina Batteries: Status, Challenges and Perspectives
The increasing penetration of renewable energy and the trend toward clean, efficient transportation have spurred growing interests in sodium-beta alumina batteries that store electrical energy via sodium ion transport across a ?"-Al2O3 solid electrolyte at elevated temperatures (typically 300~350�C). Currently, the negative electrode or anode is metallic sodium in molten state during battery operation; the positive electrode or cathode can be molten sulfur (Na-S battery) or solid transition metal halides plus a liquid phase secondary electrolyte (e.g., ZEBRA battery). Since the groundbreaking works in the sodium-beta alumina batteries a few decades ago, encouraging progress has been achieved in improving battery performance, along with cost reduction. However there remain issues that hinder broad applications and market penetration of the technologies. To better the Na-beta alumina technologies require further advancement in materials along with component and system design and engineering. This paper offers a comprehensive review on materials of electrodes and electrolytes for the Na-beta alumina batteries and discusses the challenges ahead for further technology improvement.
Lu, Xiaochuan; Xia, Guanguang; Lemmon, John P.; Yang, Zhenguo
Review of FY2001 Development Work for Vitrification of Sodium Bearing Waste
Treatment of sodium-bearing waste (SBW) at the Idaho Nuclear Technology and Engineering Center (INTEC) within the Idaho National Engineering and Environmental Laboratory is mandated by the Settlement Agreement between the Department of Energy and the State of Idaho. This report discusses significant findings from vitrification technology development during 2001 and their impacts on the design basis for SBW vitrification.
Barnes, C.M.; Taylor, D.D.
Deficiencies of sodium and iodine in grazing sheep in northern China
Deficiencies of sodium and iodine in grazing sheep in northern China DG Masters JR Lindsay SX Yu DX of Traditional Veterinary Medicine, Chinese Academy of Agricultural Science, Xiaoxihu, Lanzhou, Gansu, China An examination of the mineral status of grazing sheep at 3 sites in northern China has provided evidence
Bonding in Sodium Chloride Nanotubes: A New Analysis via Madelung Constants and Cohesive Energies
1 Bonding in Sodium Chloride Nanotubes: A New Analysis via Madelung Constants and Cohesive Energies is introduced which employs a linear relationship between nanotube cohesive energies determined via Density between ionic and cohesive bonding energies indicate that, as the nanotubes become longer, ionic bonding
Hanusa, Christopher
Ice iron/sodium film as cause for high noctilucent cloud radar reflectivity
Ice iron/sodium film as cause for high noctilucent cloud radar reflectivity P. M. Bellan1 Received] Noctilucent clouds, tiny cold electrically charged ice grains located at about 85 km altitude, exhibit by assuming the ice grains are coated by a thin metal film; substantial evidence exists indicating
Bellan, Paul M.
indirect study, coal was oxidatively de-graded with sodium dichromate and the
Cleaning Technology (Noyes Data Corporation, Park Ridge, N.J., 1981). 10. Z. Hussain, E. Umbach, D. Aindirect study, coal was oxidatively de- graded with sodium dichromate and the esterified products- vestigators concluded (17, p. 380) that "thiophene derivatives must be indige- nous to coal." The direct XANES
Howat, Ian M.
Pressure-Induced Structural Transformations of the Zintl Phase Sodium Silicide Ral Quesada Cabreraa
and reduction of Na+ to metallic sodium. We have combined our experimental studies with DFT calculations and germanides belong to the family of Zintl phases, in which polyanionic species, formed of the tetrelide atoms counterbalance the electropositive metal cations [1-3]. These compounds are interesting because the Si and Ge
Molecular Dynamic Simulation of Sodium in 7-Pin LMFBR Bundle Under Hypothetical Accident Conditions
In the frame of safety analysis of liquid metal fast breeder reactors (LMFBRs) under hypothetical Unprotected Loss of Flow (ULOF) conditions two-phase flow of sodium is simulated in a 7-pin bundle, with hexagonal lattice. Molecular dynamics, with the application of the Direct Simulation Monte Carlo (DSMC) method, and a macroscopic model describing rewetting sequences due to the flow of a sodium liquid film along the pin surfaces, are applied to simulate the coolant in the bundle. The pin surfaces and the inner surface of the hexagonal canning are treated in the Monte Carlo simulation as diffusively reflecting surfaces. Collisions of sodium molecules are computed with the 'hard-sphere' model. With respect to previous work the following improvements of the computational code were made: i) The full bundle is simulated, thus allowing for asymmetries, like a skewed power distribution, to be accounted for; ii) A pin model calculates detailed temperature distributions in the pins, so that temperature boundary conditions are computed and not imposed; iii) Post processing visualisation of computed results was developed. An out of pile sodium boiling experiment run at the Nuclear Research Center of Karlsruhe, Germany, is simulated and conclusions are drawn about the applicability of the methodology in computer codes dedicated to breeder reactors safety analysis. (authors)
Bottoni, Maurizio [University of Ferrara, Physics Department, Via Paradiso 12, I-44100 Ferrara (Italy); Bottoni, Claudio; Scanu, John [University of Pisa, Lungarno Pacinotti, 43 - 56126 Pisa (Italy)
Original article Increased late sodium current in myocytes from a canine heart failure
Original article Increased late sodium current in myocytes from a canine heart failure model and from failing human heart Carmen R. Valdivia, William W. Chu, Jielin Pu 1 , Jason D. Foell, Robert A December 2004 Abstract Electrophysiological remodeling of ion channels in heart failure causes action
Kamp, Tim
Mechanism and kinetics of a sodium-driven bacterial flagellar motor
Mechanism and kinetics of a sodium-driven bacterial flagellar motor Chien-Jung Loa,b , Yoshiyuki potential difference. It consists of an 50-nm rotor and up to 10 independent stators anchored to the cell of electrical and chemical potential. All 25 torquespeed curves had the same concave-down shape as fully
Berry, Richard