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1

Multicomponent Geothermometers | Open Energy Information  

Open Energy Info (EERE)

Multicomponent Geothermometers Multicomponent Geothermometers Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Multicomponent Geothermometers Details Activities (0) Areas (0) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Geochemical Techniques Exploration Sub Group: Geochemical Data Analysis Parent Exploration Technique: Liquid Geothermometry Information Provided by Technique Lithology: Stratigraphic/Structural: Hydrological: Thermal: Dictionary.png Multicomponent Geothermometers: The multicomponent geothermometry method consists of using full chemical analyses of water samples to compute the saturation indices (log(Q/K)) of reservoir minerals over a range of temperatures. The saturation indices are graphed as a function of temperature, and the clustering of log(Q/K) curves

2

Silica Geothermometers | Open Energy Information  

Open Energy Info (EERE)

Silica Geothermometers Silica Geothermometers Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Silica Geothermometers Details Activities (0) Areas (0) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Geochemical Techniques Exploration Sub Group: Geochemical Data Analysis Parent Exploration Technique: Liquid Geothermometry Information Provided by Technique Lithology: Stratigraphic/Structural: Hydrological: Thermal: Used to estimate reservoir temperatures. Dictionary.png Silica Geothermometers: No definition has been provided for this term. Add a Definition Introduction Some experts have stated that the factor that changes the risk assessment of a geothermal prospect the fastest is obtaining attractive chemical confirmation (geothermometry, gas analyses) that a thermal resource exists

3

Definition: Multicomponent Geothermometers | Open Energy Information  

Open Energy Info (EERE)

Multicomponent Geothermometers Multicomponent Geothermometers Jump to: navigation, search Dictionary.png Multicomponent Geothermometers The multicomponent geothermometry method consists of using full chemical analyses of water samples to compute the saturation indices (log(Q/K)) of reservoir minerals over a range of temperatures. The saturation indices are graphed as a function of temperature, and the clustering of log(Q/K) curves near zero at any specific temperature (for a group of certain reservoir minerals) is used to infer the reservoir temperature.[1] References ↑ Berkeley Lab Earth Sciences Division Website: GeoT: A Computer Program for Multicomponent Geothermometry and Geochemical Speciation Ret LikeLike UnlikeLike You like this.Sign Up to see what your friends like. rieved from

4

Multicomponent Transport of Sulfate in a Goethite-Silica Sand System  

E-Print Network (OSTI)

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.

5

Cation Geothermometers | Open Energy Information  

Open Energy Info (EERE)

Cation Geothermometers Cation Geothermometers Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Cation Geothermometers Details Activities (0) Areas (0) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Geochemical Techniques Exploration Sub Group: Geochemical Data Analysis Parent Exploration Technique: Liquid Geothermometry Information Provided by Technique Lithology: Stratigraphic/Structural: Hydrological: Thermal: Used to estimate reservoir temperatures. Dictionary.png Cation Geothermometers: No definition has been provided for this term. Add a Definition Introduction Some experts have stated that the factor that changes the risk assessment of a geothermal prospect the fastest is obtaining attractive chemical confirmation (geothermometry, gas analyses) that a thermal resource exists

6

Evaluation Of Chemical Geothermometers For Calculating Reservoir...  

Open Energy Info (EERE)

Geothermometers For Calculating Reservoir Temperatures At Nevada Geothermal Power Plants Jump to: navigation, search OpenEI Reference LibraryAdd to library Conference Paper:...

7

Chemical Geothermometers And Mixing Models For Geothermal Systems | Open  

Open Energy Info (EERE)

Geothermometers And Mixing Models For Geothermal Systems Geothermometers And Mixing Models For Geothermal Systems Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Chemical Geothermometers And Mixing Models For Geothermal Systems Details Activities (1) Areas (1) Regions (0) Abstract: Qualitative chemical geothermometers utilize anomalous concentrations of various "indicator" elements in groundwaters, streams, soils, and soil gases to outline favorable places to explore for geothermal energy. Some of the qualitative methods, such as the delineation of mercury and helium anomalies in soil gases, do not require the presence of hot springs or fumaroles. However, these techniques may also outline fossil thermal areas that are now cold. Quantitative chemical geothermometers and mixing models can provide information about present probable minimum

8

Application Of An Artificial Neural Network Model To A Na-K Geothermometer  

Open Energy Info (EERE)

Application Of An Artificial Neural Network Model To A Na-K Geothermometer Application Of An Artificial Neural Network Model To A Na-K Geothermometer Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Application Of An Artificial Neural Network Model To A Na-K Geothermometer Details Activities (3) Areas (2) Regions (0) Abstract: A new geothermometer model is proposed by applying data obtained from a known Na-K geothermometer to an artificial neural network. In this model, Na and K values were implemented as input signals and geothermometers as the output signal. Multi-layer perceptrons and back propagation were used as training algorithms for the artificial neural network. Reservoir temperatures of some geothermal fields in Turkey determined by this method are in accord with those determined from other methods.

9

A New Improved Na-K Geothermometer By Artificial Neural Networks | Open  

Open Energy Info (EERE)

Improved Na-K Geothermometer By Artificial Neural Networks Improved Na-K Geothermometer By Artificial Neural Networks Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: A New Improved Na-K Geothermometer By Artificial Neural Networks Details Activities (0) Areas (0) Regions (0) Abstract: A new Na/K geothermometer equation has been developed. The temperature function is:Concentrations are in mg/kg. The new improved geothermometer equation was developed by artificial neural networks. The normalized mean square error (NMSE) used in the new improved Na/K equation for temperatures ranging from 94 to 345°C is 0.179, which is lower than the corresponding NMSE 0.226, 0.598, 0.656, 0.268, 0.328 and 0.225 for the equations of Arnorsson et al. (1983; Geochim. Cosmochim. Acta 47, 567-577), Truesdell (1975; Proc. 2nd UN Symposium), Tonani (1980; Proc. Adv. Eur.

10

New Improved Equations For Na-K, Na-Li And Sio2 Geothermometers By Outlier  

Open Energy Info (EERE)

Improved Equations For Na-K, Na-Li And Sio2 Geothermometers By Outlier Improved Equations For Na-K, Na-Li And Sio2 Geothermometers By Outlier Detection And Rejection Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: New Improved Equations For Na-K, Na-Li And Sio2 Geothermometers By Outlier Detection And Rejection Details Activities (1) Areas (1) Regions (0) Abstract: We present new improved equations for three still widely used Na/K, Na/Li and SiO2 geothermometers (obtained by statistical treatment of the data and application of outlier detection and rejection as well as theory of error propagation) and compare them with those by Fournier and others. New equations are also developed for estimating errors associated with the use of these new geothermometric equations and comparing them with the performance of the original equations. The errors in the use of the new

11

An Empirical Na-K-Ca Geothermometer For Natural Waters | Open Energy  

Open Energy Info (EERE)

Empirical Na-K-Ca Geothermometer For Natural Waters Empirical Na-K-Ca Geothermometer For Natural Waters Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: An Empirical Na-K-Ca Geothermometer For Natural Waters Details Activities (0) Areas (0) Regions (0) Abstract: An empirical method of estimating the last temperature of water-rock interaction has been devised. It is based upon molar Na, K and Ca concentrations in natural waters from temperature environments ranging from 4 to 340°C. The data for most geothermal waters cluster near a straight line when plotted as the function vs reciprocal of absolute temperature, where Β is either or depending upon whether the water equilibrated above or below 100°C. For most waters tested, the method gives better results than the methods suggested by other workers. The ratio

12

Optimized multicomponent vs. classical geothermometry: Insights from modeling studies at the Dixie Valley geothermal area  

Science Journals Connector (OSTI)

Abstract A new geothermometry approach is explored, incorporating multicomponent geothermometry coupled with numerical optimization to provide more confident estimates of geothermal reservoir temperatures when results of classical geothermometers are inconsistent. This approach is applied to geothermal well and spring waters from the Dixie Valley geothermal area (Nevada), to evaluate the influence of salt brines mixing and dilution of geothermal fluids on calculated temperatures. The main advantage of the optimized multicomponent method over classical geothermometers is its ability to quantify the extent of dilution and gas loss experienced by a geothermal fluid, and to optimize other poorly constrained or unknown parameters (such as Al and Mg concentrations), allowing the reconstruction of the deep reservoir fluid composition and therefore gaining confidence in reservoir temperatures estimations. Because the chemical evolution of deep geothermal fluids is a combination of multiple time-dependent processes that take place when these fluids ascend to the surface, reactive transport modeling is used to assess constraints on the application of solute geothermometers. Simulation results reveal that Al and Mg concentrations of ascending fluids are sensitive to mineral precipitationdissolution affecting reservoir temperatures inferred with multicomponent geothermometry. In contrast, simulations show that the concentrations of major elements such as Na, K, and SiO2 are less sensitive to re-equilibration. Geothermometers based on these elements give reasonable reservoir temperatures in many cases, except when dilution or mixing with saline waters has taken place. Optimized multicomponent geothermometry yields more representative temperatures for such cases. Taking into account differences in estimated temperatures, and chemical compositions of the Dixie Valley thermal waters, a conceptual model of two main geothermal reservoirs is proposed. The first reservoir is located along the Stillwater range normal fault system and has an estimated temperature of 240260C. It covers the area corresponding to the geothermal field but could extend towards the south-west where deep temperatures of 200225C are estimated. The second reservoir has an estimated temperature of 175190C and extends from well 62-21 to northeastern Hyder, Lower Ranch, Fault Line, and Jersey springs.

L. Peiffer; C. Wanner; N. Spycher; E.L. Sonnenthal; B.M. Kennedy; J. Iovenitti

2014-01-01T23:59:59.000Z

13

Multicomponent Equilibrium Models for Testing Geothermometry Approaches  

SciTech Connect

Geothermometry is an important tool for estimating deep reservoir temperature from the geochemical composition of shallower and cooler waters. The underlying assumption of geothermometry is that the waters collected from shallow wells and seeps maintain a chemical signature that reflects equilibrium in the deeper reservoir. Many of the geothermometers used in practice are based on correlation between water temperatures and composition or using thermodynamic calculations based a subset (typically silica, cations or cation ratios) of the dissolved constituents. An alternative approach is to use complete water compositions and equilibrium geochemical modeling to calculate the degree of disequilibrium (saturation index) for large number of potential reservoir minerals as a function of temperature. We have constructed several forward geochemical models using The Geochemists Workbench to simulate the change in chemical composition of reservoir fluids as they migrate toward the surface. These models explicitly account for the formation (mass and composition) of a steam phase and equilibrium partitioning of volatile components (e.g., CO2, H2S, and H2) into the steam as a result of pressure decreases associated with upward fluid migration from depth. We use the synthetic data generated from these simulations to determine the advantages and limitations of various geothermometry and optimization approaches for estimating the likely conditions (e.g., temperature, pCO2) to which the water was exposed in the deep subsurface. We demonstrate the magnitude of errors that can result from boiling, loss of volatiles, and analytical error from sampling and instrumental analysis. The estimated reservoir temperatures for these scenarios are also compared to conventional geothermometers. These results can help improve estimation of geothermal resource temperature during exploration and early development.

Cooper, D. Craig; Carl D. Palmer; Robert W. Smith; Travis L. McLing

2013-02-01T23:59:59.000Z

14

silica glass  

Science Journals Connector (OSTI)

...any amorphous, pale yellow to pale green natural silica glass such as moldavite, Libyan Desert glass, contains nearly 98% silica. RI:...

2009-01-01T23:59:59.000Z

15

Exploring the reactivity of bacterial multicomponent monooxygenases  

E-Print Network (OSTI)

Chapter 1. Introduction: The Reactivity of Bacterial Multicomponent Monooxygenases Bacterial multicomponent monooxygenases constitute a remarkable family of enzymes that oxidize small, inert hydrocarbon substrates using ...

Tinberg, Christine Elaine

2010-01-01T23:59:59.000Z

16

CRYSTALLIZATION IN MULTICOMPONENT GLASSES  

SciTech Connect

In glass processing situations involving glass crystallization, various crystalline forms nucleate, grow, and dissolve, typically in a nonuniform temperature field of molten glass subjected to convection. Nuclear waste glasses are remarkable examples of multicomponent vitrified mixtures involving partial crystallization. In the glass melter, crystals form and dissolve during batch-to-glass conversion, melter processing, and product cooling. Crystals often agglomerate and sink, and they may settle at the melter bottom. Within the body of cooling glass, multiple phases crystallize in a non-uniform time-dependent temperature field. Self-organizing periodic distribution (the Liesegnang effect) is common. Various crystallization phenomena that occur in glass making are reviewed.

KRUGER AA; HRMA PR

2009-10-08T23:59:59.000Z

17

New Design Methods and Algorithms for Multi-component Distillation...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

New Design Methods and Algorithms for Multi-component Distillation Processes New Design Methods and Algorithms for Multi-component Distillation Processes multicomponent.pdf More...

18

Geochemical Techniques | Open Energy Information  

Open Energy Info (EERE)

Geochemical Techniques Geochemical Techniques Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Geochemical Techniques Details Activities (0) Areas (0) Regions (0) NEPA(1) Exploration Technique Information Exploration Group: Geochemical Techniques Exploration Sub Group: None Parent Exploration Technique: Exploration Techniques Information Provided by Technique Lithology: Stratigraphic/Structural: Hydrological: Thermal: Dictionary.png Geochemical Techniques: No definition has been provided for this term. Add a Definition Related Techniques Geochemical Techniques Geochemical Data Analysis Geothermometry Gas Geothermometry Isotope Geothermometry Liquid Geothermometry Cation Geothermometers Multicomponent Geothermometers Silica Geothermometers Thermal Ion Dispersion

19

THERMODYNAMICS Unified Model for Nonideal Multicomponent  

E-Print Network (OSTI)

THERMODYNAMICS Unified Model for Nonideal Multicomponent Molecular Diffusion Coefficients Alana and a rigorous descrip- tion of mixture nonideality in the framework of irreversible thermodynamics. Molecular

Firoozabadi, Abbas

20

Method for FractMethod for Fracture Detection Using Multicomponent...  

NLE Websites -- All DOE Office Websites (Extended Search)

Method for FractMethod for Fracture Detection Using Multicomponent Seismic Dataure Detection Using Multicomponent Seismic Data Dr. Bryan DeVault Department of Geophysics Colorado...

Note: This page contains sample records for the topic "multicomponent geothermometers silica" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Silica Scaling Removal Process  

NLE Websites -- All DOE Office Websites (Extended Search)

Silica Scaling Removal Process Silica Scaling Removal Process Scientists at Los Alamos National Laboratory have developed a novel technology to remove both dissolved and colloidal...

22

Laser ultrasonic multi-component imaging  

DOE Patents (OSTI)

Techniques for ultrasonic determination of the interfacial relationship of multi-component systems are discussed. In implementations, a laser energy source may be used to excite a multi-component system including a first component and a second component at least in partial contact with the first component. Vibrations resulting from the excitation may be detected for correlation with a resonance pattern indicating if discontinuity exists at the interface of the first and second components.

Williams, Thomas K. (Federal Way, WA); Telschow, Kenneth (Des Moines, WA)

2011-01-25T23:59:59.000Z

23

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

2014-09-23T23:59:59.000Z

24

Silica Scaling Removal Process  

NLE Websites -- All DOE Office Websites (Extended Search)

Silica Scaling Removal Process Silica Scaling Removal Process Silica Scaling Removal Process Scientists at Los Alamos National Laboratory have developed a novel technology to remove both dissolved and colloidal silica using small gel particles. Available for thumbnail of Feynman Center (505) 665-9090 Email Silica Scaling Removal Process Applications: Cooling tower systems Water treatment systems Water evaporation systems Potential mining applications (produced water) Industry applications for which silica scaling must be prevented Benefits: Reduces scaling in cooling towers by up to 50% Increases the number of cycles of concentration substantially Reduces the amount of antiscaling chemical additives needed Decreases the amount of makeup water and subsequent discharged water (blowdown) Enables considerable cost savings derived from reductions in

25

Linear matrix operations for multicomponent seismic processing  

Science Journals Connector (OSTI)

......due to the physical process of excitation, propagation...Dilley, Texas, 56th SEG Mtg Expanded Abstracts, pp...Texas, Proc. 5th EAEG Mtg, G042, Amsterdam. Cho...multicomponent VSPs, 55th EAEG Mtg, Expanded Abstracts...due to the physical process of excitation, propa......

Colin MacBeth; Xiang-Yang Li

1996-01-01T23:59:59.000Z

26

Nanoengineering Strong Silica Aerogels  

Science Journals Connector (OSTI)

Nanoengineering Strong Silica Aerogels ... In the quest for strong lightweight materials, silica aerogels would be very attractive, if they were not fragile. ... Robust, Highly Thermally Stable, CoreShell Nanostructured Metal Oxide Aerogels as High-Temperature Thermal Superinsulators, Adsorbents, and Catalysts ...

Nicholas Leventis; Chariklia Sotiriou-Leventis; Guohui Zhang; Abdel-Monem M. Rawashdeh

2002-08-23T23:59:59.000Z

27

Use of computers for multicomponent distillation calculations  

E-Print Network (OSTI)

LIBRARY 4 A I4 COLLEGE QF TEXAS USE OF COMPUTERS FOB MULTICOMPONENT DISTILLATION CALCULATIONS A Thesis By Samuel Lane Sullivan Jr, Submitted to the Graduate School of the Agricultural and Mechanical College of Texas in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE January 1959 Major Subject: Chemical Engineering USE OF COMPUTERS FOR NULTICOMPONENT DISTILLATION CALCULATIONS A Thesis By Samuel Lane Sullivan Jr. Approved as to style and content by: Chairman...

Sullivan, Samuel Lane

2012-06-07T23:59:59.000Z

28

Multicomponent Gas Diffusion in Porous Electrodes  

E-Print Network (OSTI)

Multicomponent gas transport is investigated with unprecedented precision by AC impedance analysis of porous YSZ anode-supported solid oxide fuel cells. A fuel gas mixture of H2-H2O-N2 is fed to the anode, and impedance data are measured across the range of hydrogen partial pressure (10-100%) for open circuit conditions at three temperatures (800C, 850C and 900C) and for 300mA applied current at 800C. For the first time, analytical formulae for the diffusion resistance (Rb) of three standard models of multicomponent gas transport (Fick, Stefan-Maxwell, and Dusty Gas) are derived and tested against the impedance data. The tortuosity is the only fitting parameter since all the diffusion coefficients are known. Only the Dusty Gas model leads to a remarkable data collapse for over twenty experimental conditions, using a constant tortuosity consistent with permeability measurements and the Bruggeman relation. These results establish the accuracy of the Dusty Gas model for multicomponent gas diffusion in porous med...

Fu, Yeqing; Dutta, Abhijit; Mohanram, Aravind; Pietras, John D; Bazant, Martin Z

2014-01-01T23:59:59.000Z

29

Integrable Hierarchy of Multi-Component Kaup -Boussinesq Equations  

E-Print Network (OSTI)

By using the Lax approach we find the integrable hierarchy of the two and three field Kaup-Boussinesq equations. We then give a multi-component Kaup-Boussinesq equations and their recursion operators. Finally we show that all multi-component Kaup-Boussinesq equations are the degenerate Svinolupov KdV systems.

Metin Gurses

2013-01-17T23:59:59.000Z

30

Curvature Dependency of Surface Tension in Multicomponent Systems  

E-Print Network (OSTI)

Curvature Dependency of Surface Tension in Multicomponent Systems Erik Santiso Dept. of Chemical InterScience (www.interscience.wiley.com). The effect of curvature on the surface tension of droplets for multicomponent systems, the relation between the surface tension at the surface of tension and the distance

Firoozabadi, Abbas

31

I I I . Isotherm al Multicomponent Systems  

NLE Websites -- All DOE Office Websites (Extended Search)

Nonequilibrium C ontrib ution to the Rate o f R eaction Nonequilibrium C ontrib ution to the Rate o f R eaction I I I . Isotherm al Multicomponent Systems t B. S h izg a l* Department o f C hem istry, Harvard U n iv e r sity Cambridge, M assachusetts and Lorentz I n s t it u t e fo r T h e o r e tic a l P h y sics L eid en , N etherlands and M. Karplus Department o f C hem istry, Harvard U n iv e r sity Cambridge, M assachusetts ----------------------------- L E G A L N O T I C E -----------------------------

32

Fusion reactions in multicomponent dense matter  

Science Journals Connector (OSTI)

We analyze thermonuclear and pycnonuclear fusion reactions in dense matter containing atomic nuclei of different types. We extend a phenomenological expression for the reaction rate, proposed recently by Gasques et al. [Phys. Rev. C 72, 025806 (2005)] for the one-component plasma of nuclei, to the multicomponent plasma. The expression contains several fit parameters which we adjust to reproduce the best microscopic calculations available in the literature. Furthermore, we show that pycnonuclear burning is drastically affected by an (unknown) structure of the multicomponent matter (a regular lattice, a uniform mix, etc.). We apply the results to study nuclear burning in a 12C-16O mixture. In this context, we present new calculations of the astrophysical S factors for carbon-oxygen and oxygen-oxygen fusion reactions. We show that the presence of a C-O lattice can strongly suppress carbon ignition in white dwarf cores and neutron star crusts at densities ??3109 g cm-3 and temperatures T?108 K.

D. G. Yakovlev; L. R. Gasques; A. V. Afanasjev; M. Beard; M. Wiescher

2006-09-27T23:59:59.000Z

33

Viscosity of silica  

Science Journals Connector (OSTI)

Experimental measurements of the viscosity of silica ( SiO 2 ) are critically examined; the best measurements show an activation energy of 515 kJ/mole above 1400 C and 720 kJ/mole below this temperature. The diffusion of silicon and oxygen in silica have temperature dependencies close to that of the high temperature viscosity. Mechanisms of viscous flow and diffusion of silicon and oxygen in silica are proposed that involve motion of SiO molecules. Viscous flow is proposed to result from the motion of line defects composed of SiO molecules At temperatures below 1400 C the fraction of SiO molecules in line defects changes with temperature. The relaxation of this fraction to an equilibrium value depends on the time. These proposed mechanisms are consistent with experimental measurements of silicaviscosity.

Robert H. Doremus

2002-01-01T23:59:59.000Z

34

From Multi-Component Gas Streams Opportunity  

NLE Websites -- All DOE Office Websites (Extended Search)

Separation of CO Separation of CO 2 From Multi-Component Gas Streams Opportunity Research is active on the patent-pending technology, titled "Apparatus and Process for the Separation of Gases Using Supersonic Expansion and Oblique Shock Wave Compression." This technology is available for licensing and/or further collaborative research from the U.S. Department of Energy's National Energy Technology Laboratory. Overview The separation of a gaseous mixture into constituent gases has proven to be useful for a variety of industrial and commercial applications. Currently CO 2 can be separated from multi- component gas streams using compression and refrigeration techniques in order to condense the CO 2 out of a vapor phase so that it can be mechanically separated from the stream.

35

J/$?$ absorption in a multicomponent hadron gas  

E-Print Network (OSTI)

A model for anomalous $J/\\Psi$ suppression in high energy heavy ion collisions is presented. As the additional suppression mechanism beyond standard nuclear absorption inelastic $J/\\Psi$ scattering with hadronic matter is considered. Hadronic matter is modeled as an evolving multi-component gas of point-like non-interacting particles (MCHG). Estimates for the sound velocity of the MCHG are given and the equation of state is compared with Lattice QCD data in the vicinity of the deconfinement phase transition. The approximate cooling pattern caused by longitudinal expansion is presented. It is shown that under these conditions the resulting $J/\\Psi$ suppression pattern agrees well with NA38 and NA50 data.

Dariusz Prorok; Ludwik Turko; David Blaschke

2008-08-04T23:59:59.000Z

36

New Antifouling Silica Hydrogel  

Science Journals Connector (OSTI)

There are several potential applications for these materials (e.g., blood filtration, scaffold design, and carriers for drug delivery, among many others). ... For example, this new material can be used as a filter medium for the separation of bacterial impurities from air and water, where silica hydrogels fulfill the high-surface-area requirements for a good separation medium and the antifouling characteristics of the pCBMA brush can prevent biofilm formation, thus extending the service life of the separation medium. ... Samples were prepared by dissolving 20 mg of the polymer in 5 mL of the solvent and filtered with 0.2 ?m PTFE filters. ...

ngela A. Beltrn-Osuna; Bin Cao; Gang Cheng; Sadhan C. Jana; Matthew P. Espe; Bimala Lama

2012-05-18T23:59:59.000Z

37

6 Multicomponent Density-Functional Theory R. van Leeuwen and E.K.U. Gross  

E-Print Network (OSTI)

6 Multicomponent Density-Functional Theory R. van Leeuwen and E.K.U. Gross 6.1 Introduction fields. Our goal is to set up a time-dependent multicomponent density-functional theory (TDMCDFT.K.U. Gross: Multicomponent Density-Functional Theory, Lect. Notes Phys. 706, 93­106 (2006) DOI 10

Gross, E.K.U.

38

Boundary Integral Methods for Multicomponent Fluids and Multiphase Materials  

E-Print Network (OSTI)

integral methods in two dimensions to multi-component fluid flows and multi-phase problems in materials, and more recently to multi-phase problems in materials science. By multi-fluid or multi-phase we mean systems where the constituitive properties of the fluid or material change abruptly at a dividing

39

Modelling precipitation of niobium carbide in austenite: multicomponent diffusion, capillarity,  

E-Print Network (OSTI)

Modelling precipitation of niobium carbide in austenite: multicomponent diffusion, capillarity, and coarsening N. Fujita and H. K. D. H. Bhadeshia The growth of niobium carbide in austenite involves for the overall transformation kinetics of niobium carbide precipitation in austenite that takes into account

Cambridge, University of

40

Nonequilibrium and Rarefaction Effects in Hypersonic Multicomponent Viscous Shock  

E-Print Network (OSTI)

Nonequilibrium and Rarefaction Effects in Hypersonic Multicomponent Viscous Shock Layers V.V. Riabov1 1 Introduction Planetary exploration programs [1] stimulate new studies in hypersonic aerother- modynamics. The design of hypersonic vehicles has brought renewed interests in the heat protecting methods [2

Riabov, Vladimir V.

Note: This page contains sample records for the topic "multicomponent geothermometers silica" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Sample Desorption/Ionization From Mesoporous Silica  

NLE Websites -- All DOE Office Websites (Extended Search)

Sample Desorption/Ionization From Mesoporous Silica Sample Desorption/Ionization From Mesoporous Silica Sample Desorption/Ionization From Mesoporous Silica Mesoporous silica is shown to be a sample holder for laser desorption/ionization of mass spectrometry. Available for thumbnail of Feynman Center (505) 665-9090 Email Sample Desorption/Ionization 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

42

Hydrophobic silica aerogel reinforced with carbon nanotube for oils removal  

Science Journals Connector (OSTI)

Hydrophobic silica aerogel reinforced with carbon nanotube (CNT/silica aerogel) has been prepared by forming silica layer on carboxylated CNT via a solgel process. The prepared CNT/silica aerogel can bear a l...

Tao Sun; Qin Zhuo; Xin Liu; Zhaopeng Sun; Zhanjun Wu

2014-08-01T23:59:59.000Z

43

Multicomponent 3-D characterization of a coalbed methane reservoir  

SciTech Connect

Methane is produced from fractured coalbed reservoirs at Cedar Hill Field in the San Juan Basin. Fracturing and local stress are critical to production because of the absence of matrix permeability in the coals. Knowledge of the direction of open fractures, the degree of fracturing, reservoir pressure, and compartmentalization is required to understand the flow of fluids through the reservoir. A multicomponent 3-D seismic survey was acquired to aid in coalbed methane reservoir characterization. Coalbed reservoir heterogeneities, including isolated pressure cells, zones of increased fracture density, and variable fracture directions, have been interpreted through the analysis of the multicomponent data and integration with petrophysical and reservoir engineering studies. Strike-slip faults, which compartmentalize the reservoir, have been identified by structural interpretation of the 3-D P-wave seismic data. These faults form boundaries for pressure cells that have been identified by P-wave reflection amplitude anomalies.

Shuck, E.L. [Advance Geophysical Corp., Englewood, CO (United States)] [Advance Geophysical Corp., Englewood, CO (United States); Davis, T.L.; Benson, R.D. [Colorado School of Mines, Golden, CO (United States). Geophysics Dept.] [Colorado School of Mines, Golden, CO (United States). Geophysics Dept.

1996-03-01T23:59:59.000Z

44

E-Print Network 3.0 - aniline dioxygenase-related multicomponent...  

NLE Websites -- All DOE Office Websites (Extended Search)

multicomponent Page: << < 1 2 3 4 5 > >> 1 Use of Electrochemistry To Predict Ethylene Absorption Capacities of Reactive Absorption Systems Summary: bromide salts with...

45

PHYSICAL REVIEW B 85, 155101 (2012) Electronic properties of layered multicomponent wide-band-gap oxides: A combinatorial approach  

E-Print Network (OSTI)

PHYSICAL REVIEW B 85, 155101 (2012) Electronic properties of layered multicomponent wide 2012) The structural, electronic, and optical properties of 12 multicomponent oxides with layered self-consistent screened-exchange local density approximation calculations. Strikingly, despite

Medvedeva, Julia E.

46

Multicomponent density-functional theory for electrons and nuclei Thomas Kreibich  

E-Print Network (OSTI)

Multicomponent density-functional theory for electrons and nuclei Thomas Kreibich Institut für a general multicomponent density-functional theory in which electrons and nuclei are treated completely , 71.10. w I. INTRODUCTION Density-functional theory DFT is among the most suc- cessful approaches

Gross, E.K.U.

47

Minimum Energy Consumption in Multicomponent Distillation. 3. More Than Three Products and Generalized Petlyuk Arrangements  

E-Print Network (OSTI)

Minimum Energy Consumption in Multicomponent Distillation. 3. More Than Three Products-component feed into M products has been derived. Interestingly, the minimum-energy solution in a complex solution of minimum energy for distillation of a multicomponent feed into multiple products has not been

Skogestad, Sigurd

48

Lattice Boltzmann modeling of multicomponent diffusion in narrow channels  

Science Journals Connector (OSTI)

We investigate lattice Boltzmann (LB) modeling of multicomponent diffusion for finite Knudsen numbers. Analytic solutions for binary diffusion in narrow channels, where both molecular and Knudsen diffusion are of importance, are obtained for the standard and higher-order LB methods and validated against the results from the direct simulation Monte Carlo (DSMC) method. The LB methods are shown to reproduce the diffusion slip phenomena. In the DSMC method, while fluid particles are diffusely reflected on a wall, significant component slip and a kinetic boundary layer are observed. It is shown that a higher-order LB method accurately captures the characteristics observed in the DSMC method.

Seung Hyun Kim; Heinz Pitsch; Iain D. Boyd

2009-01-08T23:59:59.000Z

49

Lattice Boltzmann model for the simulation of multicomponent mixtures  

Science Journals Connector (OSTI)

A lattice Boltzmann (LB) model for the simulation of realistic multicomponent mixtures is constructed. In the hydrodynamic limit, the LB model recovers the equations of continuum mechanics within the mixture-averaged diffusion approximation. The present implementation can be used to simulate realistic mixtures with arbitrary Schmidt numbers and molecular masses of the species. The model is applied to the mixing of two opposed jets of different concentrations and the results are in excellent agreement with a continuum model. An application to the simulation of mixtures in microflows is also presented. Results compare well with existing kinetic theory predictions of the slip coefficient for mixtures in a Couette flow.

S. Arcidiacono; I. V. Karlin; J. Mantzaras; C. E. Frouzakis

2007-10-15T23:59:59.000Z

50

Equilibrium adsorption of multicomponent gas mixtures at elevated pressures  

SciTech Connect

Equilibrium adsorption of H/sub 2/, CO, CH/sub 4/, CO/sub 2/, and H/sub 2/S (single and mixed gases-two to five species) was measured on activated carbon at pressures up to 400 psia. Temperature-dependent parameters, regressed from single-gas data, were applied to four theoretical models which predict adsorption from gas mixtures. Deviations between theory (IAS) and experiment increased with pressure and with the number of components in the mixture. None of the theories employing only single-gas data could consistently predict multicomponent adsorption. It was found that multicomponent adsorption could be predicted from the extended Langmuir equation by including an interaction parameter calculated from only single and binary data. In the application of mixture adsorption theories, it was shown that from the same model significantly different results can be obtained depending on the selection of the independent set, /T, P, X/sub i// or /T, P, Y/sub i//.

Ritter, J.A.; Yang, R.T.

1987-08-01T23:59:59.000Z

51

Electroactive Silica Nanoparticles for Biological Labeling. ...  

NLE Websites -- All DOE Office Websites (Extended Search)

novel electrochemical immuno-biosensor based on poly(guanine)-functionalized silica nanoparticle labels and mediator-generated catalytic reaction was described. The functionalized...

52

INTERACTION OF MARINE SEDIMENTS WITH DISSOLVED SILICA  

Science Journals Connector (OSTI)

In situ, these sediments had been in contact with seawater ... with seawater of high- and low-silica con- .... water after Five months storage with sediments.

2000-02-10T23:59:59.000Z

53

Silica Supported Ceria Nanoparticles: A Hybrid Nanostructure...  

NLE Websites -- All DOE Office Websites (Extended Search)

Nanoparticles: A Hybrid Nanostructure To Increase Stability And Surface Reactivity Of Nano-crystalline Silica Supported Ceria Nanoparticles: A Hybrid Nanostructure To Increase...

54

Fluorescent Silica Nanoparticles with Efficient Urinary Excretion for Nanomedicine  

Science Journals Connector (OSTI)

Fluorescent Silica Nanoparticles with Efficient Urinary Excretion for Nanomedicine ... The emerging nanomedicine landscape ... Core-shell silica nanoparticles as fluorescent labels for nanomedicine ...

Andrew A. Burns; Jelena Vider; Hooisweng Ow; Erik Herz; Oula Penate-Medina; Martin Baumgart; Steven M. Larson; Ulrich Wiesner; Michelle Bradbury

2008-12-19T23:59:59.000Z

55

Synthesis of supported carbon nanotubes in mineralized silica...  

NLE Websites -- All DOE Office Websites (Extended Search)

supported carbon nanotubes in mineralized silica-wood composites. Synthesis of supported carbon nanotubes in mineralized silica-wood composites. Abstract: Multiwall carbon...

56

Multi-component Removal in Flue Gas by Aqua Ammonia  

NLE Websites -- All DOE Office Websites (Extended Search)

component Removal in Flue Gas by Aqua Ammonia component Removal in Flue Gas by Aqua Ammonia Opportunity The Department of Energy's National Energy Technology Laboratory is seeking licensing partners interested in implementing United States Patent Number 7,255,842 entitled "Multi-component Removal in Flue Gas by Aqua Ammonia." This patent discloses a method for the removal of potential environmental-impacting compounds from flue gas streams. The method oxidizes some or all of the acid precursors such as sulfur dioxide (SO 2 ) and nitric oxides (NO x ) into sulfur trioxide and nitrogen dioxide, respectively. Following this step, the gas stream is then treated with aqua ammonia or ammonium hydroxide to capture the compounds via chemical absorption through acid-base or neutralization reactions where a fertilizer is formed.

57

Structure of Random Porous Materials: Silica Aerogel  

Science Journals Connector (OSTI)

Using small-angle x-ray scattering, we show that porous silica aerogel has a fractal backbone structure. The observed structure is traced to the underlying chemical (polymerization) and physical (colloid aggregation) growth processes. Comparison of scattering curves for aerogel with silica aggregates confirms this interpretation.

Dale W. Schaefer and Keith D. Keefer

1986-05-19T23:59:59.000Z

58

Multicomponent fluid flow by discontinuous Galerkin and mixed methods in unfractured and fractured media  

E-Print Network (OSTI)

. Numerical examples in unfractured and fractured media illustrate the efficiency and robustness in gas-condensate reservoirs), hydrology and geochemical engineering (contamination of groundwater field, sharp variations in the rock properties, and high nonlinearity of the multicomponent system due

Firoozabadi, Abbas

59

Irradiation damage in multicomponent equimolar alloys and high entropy alloys (HEAs)  

Science Journals Connector (OSTI)

......and improve the safety and efficiency of nuclear reactors, development of new and advanced nuclear materials with superior resistance to irradiation damage is necessary. Recently, a new generation of structural materials, termed as multicomponent......

Takeshi Nagase; Philip D. Rack; Takeshi Egami

2014-11-01T23:59:59.000Z

60

Structural investigations of hydroxylase proteins and complexes in bacterial multicomponent monooxygenase systems  

E-Print Network (OSTI)

Bacterial multicomponent monooxgenases (BMMs) such as toluene/o-xylene monooxygenase (ToMO), phenol hydroxylase (PH), and soluble methane monooxygenase (sMMO) catalyze hydrocarbon oxidation reactions at a carboxylatebridged ...

McCormick, Michael S. (Michael Scott)

2008-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "multicomponent geothermometers silica" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Numerical models of caldera deformation: Effects of multiphase and multicomponent hydrothermal fluid flow  

E-Print Network (OSTI)

and poroelastic deformation using a range of realistic physical parameters and processes. Hydrothermal fluidNumerical models of caldera deformation: Effects of multiphase and multicomponent hydrothermal. Although hydrothermal fluids have been discussed as a possible deformation agent, very few quantitative

62

Analytical Solutions for Multicomponent, Two-Phase Flow in Porous Media with Double Contact Discontinuities  

E-Print Network (OSTI)

This paper presents the first instance of a double contact discontinuity in analytical solutions for multicomponent, two-phase flow in porous media. We use a three-component system with constant equilibrium ratios and fixed ...

Orr, F. M. Jr

63

Silica Nanoparticles and Frameworks from Rice Husk Biomass  

Science Journals Connector (OSTI)

Silica Nanoparticles and Frameworks from Rice Husk Biomass ... silica nanoparticles; rice husk; porous; biomass; hierarchical ... (22-25) Although the silica structures from RHs appear to be much less complicated and less visually attractive compared to the ones from diatoms, the large quantities of RH biomass offer an opportunity for mass production of nanostructured silica for industrial applications. ...

Weixing Wang; Jarett C. Martin; Xiaotian Fan; Aijie Han; Zhiping Luo; Luyi Sun

2011-12-29T23:59:59.000Z

64

Synthesis, adsorption and regeneration of nanoporous silica aerogel and silica aerogel-activated carbon composites  

Science Journals Connector (OSTI)

Abstract Usage of aerogels as an adsorbent has become more widespread because of its specifications such as high porosity and specific surface. Nanometer silica aerogel and silica aerogel-activated carbon composites were synthesized using a water glass precursor by ambient pressure drying method. Then, the adsorption capacity of synthesized adsorbents was studied in terms of benzene and ethyl benzene adsorption by chromatography method for continuous and batch testing. Results showed that silica aerogel and silica aerogel-activated carbon composites had high tendency for benzene and ethyl benzene adsorption. Silica aerogel showed maximum adsorption capacity of 2.3gg?1 and 0.7gg?1 in static adsorption of benzene and ethyl benzene respectively. Also, in dynamic adsorption of benzene and ethyl benzene, silica aerogel had maximum equilibrium adsorption capacity of 0.954gg?1 and 0.219gg?1 respectively. Minimum equilibrium adsorption capacity in benzene and ethyl benzene static adsorption was related to activated carbon with 0.7gg?1 and silica aerogel2wt% activated carbon with 0.25gg?1 respectively. After adsorption process, silica aerogel and silica aerogel0.5wt% activated carbon composite were regenerated by solvent extractionthermal treatment method and, after at least 15 adsorption/desorption cycles, their adsorption capacity became fixed.

Akbar Mohammadi; Jafarsadegh Moghaddas

2014-01-01T23:59:59.000Z

65

Imprint of multicomponent dark matter on AMS-02  

Science Journals Connector (OSTI)

The multicomponent decaying dark matter (DM) scenario is investigated to explain the possible excesses in the positron fraction by PAMELA and recently confirmed by AMS-02, and in the total e++e? flux observed by Fermi-LAT. By performing the ?2 fits, we find that two DM components are already enough to give a reasonable fit of both AMS-02 and Fermi-LAT data. The best-fitted results show that the heavier DM component with its mass of 1.5TeV dominantly decays through the ? channel, while the lighter one of 100GeV decays mainly through the ? channel. As a by-product, the fine structure around 100GeV observed by AMS-02 and Fermi-LAT can be naturally explained by the dropping due to the lighter DM component. With the obtained model parameters by the fitting, we calculate the diffuse ?-ray emission spectrum in this two-component DM scenario, and find that it is consistent with the data measured by Fermi-LAT. We also construct a microscopic particle DM model to naturally realize the two-component DM scenario, and point out an interesting neutrino signal which will possibly be measured in the near future by IceCube.

Chao-Qiang Geng; Da Huang; Lu-Hsing Tsai

2014-03-25T23:59:59.000Z

66

Sputter deposition for multi-component thin films  

DOE Patents (OSTI)

Ion beam sputter-induced deposition using a single ion beam and a multicomponent target is capable of reproducibly producing thin films of arbitrary composition, including those which are close to stoichiometry. Using a quartz crystal deposition monitor and a computer controlled, well-focused ion beam, this sputter-deposition approach is capable of producing metal oxide superconductors and semiconductors of the superlattice type such as GaAs-AlGaAs as well as layered metal/oxide/semiconductor/superconductor structures. By programming the dwell time for each target according to the known sputtering yield and desired layer thickness for each material, it is possible to deposit composite films from a well-controlled sub-monolayer up to thicknesses determined only by the available deposition time. In one embodiment, an ion beam is sequentially directed via a set of X-Y electrostatic deflection plates onto three or more different element or compound targets which are constituents of the desired film. In another embodiment, the ion beam is directed through an aperture in the deposition plate and is displaced under computer control to provide a high degree of control over the deposited layer. In yet another embodiment, a single fixed ion beam is directed onto a plurality of sputter targets in a sequential manner where the targets are each moved in alignment with the beam under computer control in forming a multilayer thin film. This controlled sputter-deposition approach may also be used with laser and electron beams.

Krauss, Alan R. (Plainfield, IL); Auciello, Orlando (Cary, NC)

1990-01-01T23:59:59.000Z

67

Sputter deposition for multi-component thin films  

DOE Patents (OSTI)

Ion beam sputter-induced deposition using a single ion beam and a multicomponent target is capable of reproducibly producing thin films of arbitrary composition, including those which are close to stoichiometry. Using a quartz crystal deposition monitor and a computer controlled, well-focused ion beam, this sputter-deposition approach is capable of producing metal oxide superconductors and semiconductors of the superlattice type such as GaAs-AlGaAs as well as layered metal/oxide/semiconductor/superconductor structures. By programming the dwell time for each target according to the known sputtering yield and desired layer thickness for each material, it is possible to deposit composite films from a well-controlled sub-monolayer up to thicknesses determined only by the available deposition time. In one embodiment, an ion beam is sequentially directed via a set of X-Y electrostatic deflection plates onto three or more different element or compound targets which are constituents of the desired film. In another embodiment, the ion beam is directed through an aperture in the deposition plate and is displaced under computer control to provide a high degree of control over the deposited layer. In yet another embodiment, a single fixed ion beam is directed onto a plurality of sputter targets in a sequential manner where the targets are each moved in alignment with the beam under computer control in forming a multilayer thin film. This controlled sputter-deposition approach may also be used with laser and electron beams. 10 figs.

Krauss, A.R.; Auciello, O.

1990-05-08T23:59:59.000Z

68

Properties and Structures of Sulfonated Syndiotactic Polystyrene Aerogel and Syndiotactic Polystyrene/Silica Hybrid Aerogel.  

E-Print Network (OSTI)

??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

2014-01-01T23:59:59.000Z

69

Vibrational amplitudes in vitreous silica  

Science Journals Connector (OSTI)

A model structure of vitreous silica, for which the vibrational frequencies and eigenmodes were calculated from first principles, is used to investigate vibrational amplitudes. Calculated mean-square displacements for oxygen and silicon atoms are obtained as a function of temperature. The square displacement tensors of oxygen atoms show a marked anisotropic character, which is related to the local geometry. The displacements of oxygen atoms along the three principal directions can be associated to distinct parts of the vibrational spectrum, as evidenced by their thermal dependence. These anisotropic effects directly affect the elastic and the static structure factors, which are sensitive to the correlation between displacements of different atoms along their connecting direction. This description shows that the observed widths for Si-O and O-O correlations mainly derive from atomic vibrations rather than from structural disorder. Anisotropic correlations between different atoms are shown to be important up to a distance of 4 , i.e., involving atoms that belong to corner-sharing tetrahedra. The scattering functions, calculated at finite temperature and in the harmonic approximation, show good agreement with experiment. In particular, the comparison between the static and the elastic structure factors yields a characterization of the correlated displacements in accord with experimental observations. The static structure factor is significantly affected by anisotropic correlations, but shows only a weak dependence on temperature between 0 and 300 K.

Alfredo Pasquarello

2000-02-01T23:59:59.000Z

70

Fluoroalkylsilane versus alkylsilane as hydrophobic agents for silica and silicates  

Science Journals Connector (OSTI)

Hydrophobic powders were obtained via surface modification of silica or magnesium silicate with selected silanes. A modified precipitation method, carried out in an emulsion system, was used for monodisperse silica synthesis, while magnesium silicate ...

Damian Ambrozewicz; Filip Ciesielczyk; Magdalena Nowacka; Joanna Karasiewicz; Adam Piasecki; Hieronim Maciejewski; Teofil Jesionowski

2013-01-01T23:59:59.000Z

71

Electrostatically Tuned Interactions in Silica Microsphere-Polystyrene Nanoparticle Mixtures  

E-Print Network (OSTI)

Electrostatically Tuned Interactions in Silica Microsphere-Polystyrene Nanoparticle Mixtures Angel: July 26, 2005 We explore the generality of nanoparticle haloing1 as a novel colloidal stabilization mechanism in binary mixtures of silica microspheres and polystyrene nanoparticles. By selectively tuning

Lewis, Jennifer

72

Nano-Macro Correlation of Nano-Silica Concrete  

Science Journals Connector (OSTI)

Concrete mixes using progressively finer size nano-silica particles (7150nm) were prepared to study the effect of nano-size pozzolans (nano-silica). Conventional compression tests demonstrated progressively high...

Joan Schoepfer; Arup Maji

2013-01-01T23:59:59.000Z

73

Silane Modification of Glass and Silica Surfaces to Obtain Equally...  

NLE Websites -- All DOE Office Websites (Extended Search)

Silane Modification of Glass and Silica Surfaces to Obtain Equally Oil-Wet Surfaces in Glass-Covered Silicon Micromodel Silane Modification of Glass and Silica Surfaces to Obtain...

74

Non-supercritically dried silicasilica composite aerogel and its possible application for confining simulated nuclear wastes  

Science Journals Connector (OSTI)

The simpler non-supercritical drying approach has been used for the first time for the preparation of silicasilica composite aerogels (CA) and the efficiency of the process being demonstrated by testing the u...

P. R. Aravind; P. Shajesh; P. Mukundan

2008-05-01T23:59:59.000Z

75

Silica Sol as a Nanoglue: Flexible Synthesis of Composite Aerogels  

Science Journals Connector (OSTI)

...Vulcan carbonsilica aerogel composites are not conductive...low-reflectivity monoliths and coatings. Although light from...through a pure silica aerogel, no light passes through...low-reflectivity monoliths and coatings. Although light from...through a pure silica aerogel, no light passes through...

Catherine A. Morris; Michele L. Anderson; Rhonda M. Stroud; Celia I. Merzbacher; Debra R. Rolison

1999-04-23T23:59:59.000Z

76

Multicomponent reactive transport modeling at the Ratones uranium mine, Cceres (Spain)  

E-Print Network (OSTI)

Multicomponent reactive transport modeling at the Ratones uranium mine, Cáceres (Spain) Modelación management. The Ratones uranium mine was abandoned and flooded in 1974. Due to its reducing underground water, uranium, reactive transport, granite hydrochemistry, Ratones mine. Resumen La inundación de minas

Politècnica de Catalunya, Universitat

77

Integrated Column Designs for Minimum Energy and Entropy Requirements in Multicomponent Distillation  

E-Print Network (OSTI)

Distillation Ivar J. Halvorsen1 and Sigurd Skogestad Norwegian University of Science and Technology, Department at the Topical conference on Separations Technology, Session 23 - Distillation Modeling and Processes II. 2001 Column Designs for Minimum Energy and Entropy Requirements in Multicomponent Distillation Ivar J

Skogestad, Sigurd

78

Burr-XII Distribution Parametric Estimation and Estimation of Reliability of Multicomponent Stress-Strength  

E-Print Network (OSTI)

1 Burr-XII Distribution Parametric Estimation and Estimation of Reliability of Multicomponent-strength reliability by assuming the Burr-XII distribution. The research methodology adopted here is to estimate. By using real data sets we well illustrate the procedure. Key Words: Burr-XII distribution, reliability

Kundu, Debasis

79

Chemistry of Silica in Cerro Prieto Brines  

E-Print Network (OSTI)

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.

2010-01-01T23:59:59.000Z

80

Chemistry of Silica in Cerro Prieto Brines  

E-Print Network (OSTI)

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, Oleh

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "multicomponent geothermometers silica" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Origin of Libyan Desert Silica-Glass  

Science Journals Connector (OSTI)

... of germanium, using a modified method of Schneider and Sandell4, in Libyan Desert silica-glass, Libyan Desert sandstone, a Libyan Desert quartzite, two Libyan Desert sands, Aouelloul crater ... Desert sandstone, a Libyan Desert quartzite, two Libyan Desert sands, Aouelloul crater 'impactite' glass, two obsidians, the average for tektites from eleven different localities, including all known ...

ALVIN J. COHEN

1959-05-30T23:59:59.000Z

82

Molecular sieving silica membrane fabrication process  

DOE Patents (OSTI)

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. (400 Maple St. SE., Apartment 112, Albuquerque, NM 87106); Brinker, Charles Jeffrey (14 Eagle Nest Dr., NE., Albuquerque, NM 87122)

1998-01-01T23:59:59.000Z

83

Molecular sieving silica membrane fabrication process  

DOE Patents (OSTI)

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)

1999-01-01T23:59:59.000Z

84

Iron acetylacetonate complex anchored on silica xerogel polymer  

Science Journals Connector (OSTI)

Iron(III) acetylacetonate complex immobilized on silica surface was obtained by the following three steps synthesis: (i) synthesis of organic precursor (acacsil) containing the acetylacetonate (acac) group; (ii) simultaneous polycondensation of the acacsil with the tetraethylorthosilicate (TEOS) by the solgel method resulting in the acac/silica xerogel; and (iii) complexation of the Fe(III) on the acac sites of the xerogel surface forming a Fe-acac/silica xerogel. The xerogels, acac/silica and Fe-acac/silica, are hybrid polymers that present a covalent organic/inorganic interface between the acac groups and silica. Xerogels were characterized by using scanning electron microscopy, energy dispersive spectroscopy, infrared spectroscopy, N2 adsorption desorption isotherms (pore size distribution and surface area) and elemental analysis. The Fe-acac/silica xerogel was tested as heterogeneous catalyst for the cis-cyclooctene epoxidation, employing the same conditions of the homogeneous Mukaiyama system.

Marcia C. Brasil; Edilson V. Benvenutti; Jos R. Gregrio; Annelise E. Gerbase

2005-01-01T23:59:59.000Z

85

Changes in the catalytic properties of a multicomponent molybdenum catalyst under vibro-fluidized catalyst bed conditions  

Science Journals Connector (OSTI)

Activation effect of oxidative dehydrogenation of butene-l on a multicomponent molybdenum catalyst at various temperatures has been studied by ... only reactive but also adsorption properties of the catalyst surf...

A. V. Simakov; S. A. Veniaminov; W. Walkov

1985-01-01T23:59:59.000Z

86

Assessment of the possibilities of the dual-energy X-ray absorptiometry of multicomponent samples with variable content  

Science Journals Connector (OSTI)

Possibility of the employment of a linear coupling equation of mass attenuation coefficients for two energies for the density determination by dual-energy X-ray absorptiometry of multicomponent samples with varia...

N. A. Antropov; D. A. Karpov; Yu. Yu. Kryuchkov

2012-09-01T23:59:59.000Z

87

Interaction of silica nano-particles with a flat silica surface through neutron reflectometry  

SciTech Connect

Neutron reflectometry (NR) was employed to study the interaction of nanosized silica particles with a flat silica surface in aqueous solutions. Unlike other experimental tools that are used to study surface interactions, NR can provide information on the particle density profile in the solution near the interface. Two types of silica particles (25 and 100 nm) were suspended in aqueous solutions of varying ionic strength. Theoretical calculations of the surface interaction potential between a particle and a flat silica surface using the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory were compared to the experimental data. The theory predicts that the potential energy is highly dependent on the ionic strength. In high ionic strength solutions, NR reveals a high concentration of particles near the flat silica surface. Under the same conditions, theoretical calculations show an attractive force between a particle and a flat surface. For low ionic strength solutions, the particle concentration near the surface obtained from NR is the same as the bulk concentration, while depletion of particles near the surface is expected because of the repulsion predicted by the DLVO theory.

Chung, Eunhyea [Georgia Institute of Technology; Yiacoumi, Sotira [Georgia Institute of Technology; Halbert, Candice E [ORNL; Ankner, John Francis [ORNL; Wang, Wei [ORNL; Tsouris, Costas [ORNL

2012-01-01T23:59:59.000Z

88

Cryogenic properties of optomechanical silica microcavities  

E-Print Network (OSTI)

We present the optical and mechanical properties of high-Q fused silica microtoroidal resonators at cryogenic temperatures (down to 1.6 K). A thermally induced optical multistability is observed and theoretically described; it serves to characterize quantitatively the static heating induced by light absorption. Moreover the influence of structural defect states in glass on the toroid mechanical properties is observed and the resulting implications of cavity optomechanical systems on the study of mechanical dissipation discussed.

Olivier Arcizet; Rmi Rivire; Albert Schliesser; Tobias J. Kippenberg

2009-01-09T23:59:59.000Z

89

Novel silica-based ion exchange resin  

SciTech Connect

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.

NONE

1997-11-01T23:59:59.000Z

90

Silica powders for powder evacuated thermal insulating panel and method  

DOE Patents (OSTI)

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)

1996-01-01T23:59:59.000Z

91

Silica powders for powder evacuated thermal insulating panel and method  

DOE Patents (OSTI)

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.

1996-01-02T23:59:59.000Z

92

Silica powders for powder evacuated thermal insulating panel and method  

DOE Patents (OSTI)

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)

1995-01-01T23:59:59.000Z

93

Silica powders for powder evacuated thermal insulating panel and method  

DOE Patents (OSTI)

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)

1994-01-01T23:59:59.000Z

94

Mixed solitons in a (2+1)-dimensional multicomponent long-waveshort-wave system  

Science Journals Connector (OSTI)

We derive a (2+1)-dimensional multicomponent long-wave?short-wave resonance interaction (LSRI) system as the evolution equation for propagation of N-dispersive waves in weak Kerr-type nonlinear medium in the small-amplitude limit. The mixed- (bright-dark) type soliton solutions of a particular (2+1)-dimensional multicomponent LSRI system, deduced from the general multicomponent higher-dimensional LSRI system, are obtained by applying the Hirota's bilinearization method. Particularly, we show that the solitons in the LSRI system with two short-wave components behave like scalar solitons. We point out that for an N-component LSRI system with N>3, if the bright solitons appear in at least two components, interesting collision behavior takes place, resulting in energy exchange among the bright solitons. However, the dark solitons undergo standard elastic collision accompanied by a position shift and a phase shift. Our analysis on the mixed bound solitons shows that the additional degree of freedom which arises due to the higher-dimensional nature of the system results in a wide range of parameters for which the soliton collision can take place.

T. Kanna; M. Vijayajayanthi; M. Lakshmanan

2014-10-01T23:59:59.000Z

95

Defect Migration and Recombination in Nanoindentation of Silica...  

NLE Websites -- All DOE Office Websites (Extended Search)

Defect Migration and Recombination in Nanoindentation of Silica Glass Authors: Nomura, K., Chen, Y., Kalia, R.K., Nakano, A., Vashishta, P. Deformation, plasticity, and flow in...

96

Characterisation of Dust Particles Trapped in Silica Aerogels.  

E-Print Network (OSTI)

?? 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

2011-01-01T23:59:59.000Z

97

Feasibility of using silica aerogel as insulation for buildings.  

E-Print Network (OSTI)

?? 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

2012-01-01T23:59:59.000Z

98

Fibrous composites comprising carbon nanotubes and silica  

DOE Patents (OSTI)

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)

2011-10-11T23:59:59.000Z

99

Cryogenic properties of optomechanical silica microcavities  

Science Journals Connector (OSTI)

We report the study of the optical and mechanical properties of high-Q fused silica microtoroidal resonators at cryogenic temperatures (down to 1.6 K). A thermally induced optical multistability is observed and theoretically described, originating from the reverse thermally induced optical frequency shift. Moreover the influence of structural defect states (two level fluctuators) on their mechanical properties is observed and probed at an unprecedentedly achieved low phonon number. The resulting implications for cavity optomechanics and studies of mechanical decoherence are also discussed.

O. Arcizet; R. Rivire; A. Schliesser; G. Anetsberger; T. J. Kippenberg

2009-08-12T23:59:59.000Z

100

Suspended bridge-like silica 22 beam splitter on silicon  

Science Journals Connector (OSTI)

We report a successful experimental realization of a 22 suspended silica splitter integrated on a silicon substrate. The silica splitter was photo-lithographically patterned,...

Zhang, Xiaomin; Armani, Andrea M

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "multicomponent geothermometers silica" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Silica Bridge Impact on Hollow-Core Bragg Fiber Transmission Properties  

Science Journals Connector (OSTI)

The silica bridges impact on the hollow-core Bragg fiber guiding properties is investigated. Results demonstrate that silica nanosupports are responsible for the surface mode...

Poli, Federica; Foroni, Matteo; Giovanelli, Daniele; Cucinotta, Annamaria; Selleri, Stefano; Jensen, Jesper Bo; Lgsgaard, Jesper; Bjarklev, Anders; Vienne, Guillaume; Jakobsen, Christian; Broeng, Jes

102

Tailoring Structure Property Relationships and Elastic Phenomenon in Native and Polymer Reinforced Silica Aerogels.  

E-Print Network (OSTI)

?? 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.

2010-01-01T23:59:59.000Z

103

Preparation of superhydrophobic and transparent micro-nano hybrid coatings from polymethylhydroxysiloxane and silica ormosil aerogels  

Science Journals Connector (OSTI)

Superhydrophobic and transparent polymethylhydroxysiloxane (PMHOS)/silica ormosil aerogel hybrids were prepared successfully by mixing of PMHOS with various weight percentages of silica ormosil aerogels (as sy...

Saravanan Nagappan; Jin Joo Park; Sung Soo Park; Chang-Sik Ha

2014-12-01T23:59:59.000Z

104

Dye-Doped Silica Nanoparticle Labels/Protein Microarray for Detection...  

NLE Websites -- All DOE Office Websites (Extended Search)

Dye-Doped Silica Nanoparticle LabelsProtein Microarray for Detection of Protein Biomarkers. Dye-Doped Silica Nanoparticle LabelsProtein Microarray for Detection of Protein...

105

Single molecule studies of meso/macro porous silica materials and gradient films.  

E-Print Network (OSTI)

??The preparation of mesoporous/macroporous silica materials and polarity gradient thin film are introduced in this thesis. These porous silica materials and gradient materials have the (more)

Ye, Fangmao

2009-01-01T23:59:59.000Z

106

Controlled morphogenesis of amorphous silica and its relevance to biosilicification  

Science Journals Connector (OSTI)

...to silica in areas where silica...component of all plasma membranes...in a flow air atmosphere. 29Si MAS NMR...spectrometer at 79.49 MHz under single...Specific surface areas were calculated...particles at a large scale. Table...also show a large increase at...BET surface area and pore volume...

Jia-Yuan Shi; Qi-Zhi Yao; Xi-Ming Li; Gen-Tao Zhou; Sheng-Quan Fu

107

Community Geothermal Technology Program: Silica bronze project. Final report  

SciTech Connect

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.

1989-10-01T23:59:59.000Z

108

Supercritical carbon dioxide behavior in porous silica aerogel  

Science Journals Connector (OSTI)

Supercritical carbon dioxide within a porous silica aerogel behaves as a two-phase system formed by a film next to the silica walls and a remaining fluid phase. Small-angle neutron scattering allows one to determine the structural parameters of the involved phases.

Ciccariello, S.

2010-11-27T23:59:59.000Z

109

Simulations Reveal That Earth's Silica Is Predominantly Superficial - NERSC  

NLE Websites -- All DOE Office Websites (Extended Search)

Reveal Reveal Earth's Silica Is Predominantly Superficial Simulations Reveal Earth's Silica Is Predominantly Superficial May 24, 2010 Silica is one of the most common minerals on Earth. Not only does it make up two-thirds of our planet's crust, it is also used to create a variety of materials from glass to ceramics, computer chips and fiber optic cables. Yet new quantum mechanics results generated by a team of physicists from Ohio State University (OSU) show that this mineral only populates our planet superficially-in other words, silica is relatively uncommon deep within the Earth. Cross-section of the Earth Using several of the largest supercomputers in the nation, including the National Energy Research Scientific Computing Center's (NERSC) Cray XT4 "Franklin" system, the team simulated the behavior of silica in

110

Generalization of internal Density Functional Theory and Kohn-Sham scheme to multicomponent systems, and link with traditional DFT  

E-Print Network (OSTI)

We generalize the recently developped "internal" Density Functional Theory (DFT) and Kohn-Sham scheme to multicomponent systems. We obtain a general formalism, applicable for the description of multicomponent self-bound systems (as molecules where the nuclei are treated explicitely, atomic nuclei and mix of 3He and 4He droplets), where the fundamental translational symmetry has been treated correctly. The main difference with traditional DFT is the explicit inclusion of center-of-mass correlations in the functional. A large part of the paper is dedicated to the application to molecules, which permits among other to clarify the approximations that underly traditional DFT.

Jeremie Messud

2011-11-21T23:59:59.000Z

111

Phase behavior of methane hydrate in silica sand  

Science Journals Connector (OSTI)

Abstract Two kinds of silica sand powder with different particle size were used to investigate the phase behavior of methane hydrate bearing sediment. In coarse-grained silica sand, the measured temperature and pressure range was (281.1 to 284.2)K and (5.9 to 7.8)MPa, respectively. In fine-grained silica sand, the measured temperature and pressure range was (281.5 to 289.5)K and (7.3 to 16.0)MPa, respectively. The results show that the effect of coarse-grained silica sand on methane hydrate phase equilibrium can be ignored; however, the effect of fine-grained silica sand on methane hydrate phase equilibrium is significant, which is attributed to the depression of water activity caused by the hydrophilicity and negatively charged characteristic of silica particle as well as the pore capillary pressure. Besides, the analysis of experimental results using the GibbsThomson equation shows that methane hydrate phase equilibrium is related to the pore size distribution of silica sand. Consequently, for the correct application of phase equilibrium data of hydrate bearing sediment, the geological condition and engineering requirement should be taken into consideration in gas production, resource evaluation, etc.

Shi-Cai Sun; Chang-Ling Liu; Yu-Guang Ye; Yu-Feng Liu

2014-01-01T23:59:59.000Z

112

Total Neutron Scattering in Vitreous Silica  

Science Journals Connector (OSTI)

The structure of Corning superpure vitreous silica glass has been investigated with neutrons. A new method of analysis using variable neutron wavelengths and the measurement of total scattering cross sections from transmission experiments is developed and the results are compared with those from differential x-ray scattering. The total neutron scattering method permits a simple and direct structure analysis with resolution apparently superior to x-rays. The preliminary results compare well in a first approximation analysis with the basic structure model of Warren and others and in addition the neutron-determined atomic radial distribution curve exhibits some finer details than the x-ray results. Thermal inelastic scattering of neutrons was corrected for in an approximate way.

R. J. Breen; R. M. Delaney; P. J. Persiani; A. H. Weber

1957-01-15T23:59:59.000Z

113

A Robust MEMS Based Multi-Component Sensor for 3D Borehole Seismic Arrays  

SciTech Connect

The objective of this project was to develop, prototype and test a robust multi-component sensor that combines both Fiber Optic and MEMS technology for use in a borehole seismic array. The use such FOMEMS based sensors allows a dramatic increase in the number of sensors that can be deployed simultaneously in a borehole seismic array. Therefore, denser sampling of the seismic wave field can be afforded, which in turn allows us to efficiently and adequately sample P-wave as well as S-wave for high-resolution imaging purposes. Design, packaging and integration of the multi-component sensors and deployment system will target maximum operating temperature of 350-400 F and a maximum pressure of 15000-25000 psi, thus allowing operation under conditions encountered in deep gas reservoirs. This project aimed at using existing pieces of deployment technology as well as MEMS and fiber-optic technology. A sensor design and analysis study has been carried out and a laboratory prototype of an interrogator for a robust borehole seismic array system has been assembled and validated.

Paulsson Geophysical Services

2008-03-31T23:59:59.000Z

114

Calculation of multicomponent ionic diffusion from zero to high concentration: II. Inclusion of associated ion species  

SciTech Connect

This paper presents a theoretical model of multicomponent ionic diffusion which is valid to high concentration for systems which show ion association. The results of the authors' formulations are contrasted with those of more simplified models for systems containing Na{sub 2}SO{sub 4} and MgSO{sub 4}, as well as for multicomponent natural seawater. The differences between their model and simplified models are significant, especially at high concentration. Inconsistencies which may develop with the use of the simplified approaches are demonstrated. The authors' approach requires considerable data which are not available at temperatures other than 25{degree}C. Therefore, other approaches which are based only on data at infinite dilution are of great interest. They show here that, if chemical potential derivatives are included in the infinite dilution model of Nernst and Hartley which uses only infinite dilution mobilities, the model can be extended to slightly concentrated solutions. This extended Nernst-Hartley model gives good agreement with all of the existing experimental mutual diffusion coefficient data at concentrations below about 0.2 M in the six component system Na-K-Ca-Mg-Cl-SO{sub 4}-H{sub 2}O. This may be the most reliable way to extend infinite dilution data into more concentrated regions. In the systems they have studied, the inclusion of ion-association species for weakly interacting species does not appear to provide significant improvement over the generalized Nernst-Hartley model.

Felmy, A.R.; Weare, J.H. (Univ. of California, San Diego, La Jolla (USA))

1991-01-01T23:59:59.000Z

115

A new pulsed laser deposition technique: Scanning multi-component pulsed laser deposition method  

SciTech Connect

The scanning multi-component pulsed laser deposition (PLD) method realizes uniform depositions of desired coatings by a modified pulsed laser deposition process, preferably with a femto-second laser-system. Multi-component coatings (single or multilayered) are thus deposited onto substrates via laser induced ablation of segmented targets. This is achieved via horizontal line-scanning of a focused laser beam over a uniformly moving target's surface. This process allows to deposit the desired composition of the coating simultaneously, starting from the different segments of the target and adjusting the scan line as a function of target geometry. The sequence and thickness of multilayers can easily be adjusted by target architecture and motion, enabling inter/intra layer concentration gradients and thus functional gradient coatings. This new, simple PLD method enables the achievement of uniform, large-area coatings. Case studies were performed with segmented targets containing aluminum, titanium, and niobium. Under the laser irradiation conditions applied, all three metals were uniformly ablated. The elemental composition within the rough coatings obtained was fixed by the scanned area to Ti-Al-Nb = 1:1:1. Crystalline aluminum, titanium, and niobium were found to coexist side by side at room temperature within the substrate, without alloy formation up to 600 deg. C.

Fischer, D.; Jansen, M. [Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569 Stuttgart (Germany); Fuente, G. F. de la [Instituto de Ciencia de Materiales de Aragon (CSIC-Universidad de Zaragoza), Maria de Luna, 3, 50018 Zaragoza (Spain)

2012-04-15T23:59:59.000Z

116

Polymer/Silica Composite Films as Luminescent Oxygen Sensors  

Science Journals Connector (OSTI)

10-14 In this technique, an object (a model airplane or wing, a turbine blade, or an automobile) coated with an oxygen-sensing polymer coating (pressure-sensitive paint, PSP) is examined in a wind tunnel. ... To examine the influence of the silica particles on oxygen diffusion and oxygen permeation in these films, we carried out both time-scan and pulsed-laser experiments as a function of silica content on films containing PtOEP. ... We rationalize this result by imagining that oxygen adsorption onto the silica surface is diffusion-controlled. Fickian diffusion through the PDMS matrix controls the rate of quenching of dye molecules bound to the silica particles. ...

Xin Lu; Ian Manners; Mitchell A. Winnik

2001-03-06T23:59:59.000Z

117

Smectic ordering in polymer liquid crystal-silica aerogel nanocomposites  

Science Journals Connector (OSTI)

Two series of side chain liquid crystal (SCLC) polyacrylate-silica aerogel nanocomposites have been investigated by small-angle X-ray scattering (SAXS) and differential scanning calorimetry (DSC). The first se...

H. Westfahl Jr.

2005-02-01T23:59:59.000Z

118

Different methods to derive pure silica from agriculture waste  

Science Journals Connector (OSTI)

Rice residues are important natural resources, the management of these residues is a major challenge for environment protection. The use of different techniques to produce silica with minimal mineral contaminants having high Specific Surface Area (SSA) has been investigated. The different methods used depended on treatment of rice hulls with different dilute organic acids and hydrochloric acid, without the risk of using corrosive, toxic and hazardous substances in the burning process. Different powdered silica obtained are characterised by particle size distribution, crystallographic structure, BET SSA and chemical analysis. X-ray Diffraction patterns revealed the amorphous nature of silica. The major impurities of silica produced from rice hulls were Na, K and Ca salts.

Azza El-Maghraby; Heba A. El-Deeb

2012-01-01T23:59:59.000Z

119

Scratch resistance of different silica filled resins for obturation materials  

E-Print Network (OSTI)

Scratch resistance of different silica filled resins for obturation materials B. Bilyeu1,2 , W have scratch resistance values in the range appropriate for applications as obturation materials. Keywords: Obturation materials, Polymerzsilica, Hybrids, Polymer tribology, Scratch resistance Introduction

North Texas, University of

120

Quantification of residual stress from photonic signatures of fused silica  

SciTech Connect

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 NASAs 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)

2014-02-18T23:59:59.000Z

Note: This page contains sample records for the topic "multicomponent geothermometers silica" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Operating Experience Level 3, Dangers of Respirable Silica  

Energy.gov (U.S. Department of Energy (DOE))

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.

122

Electrospinning of silica nanofibers: characterization and application to biosensing  

E-Print Network (OSTI)

; 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

2009-06-02T23:59:59.000Z

123

Mesosynthesis of ZnO?Silica Composites for Methanol Nanocatalysis  

Science Journals Connector (OSTI)

5 Mesoporous silica materials mostly of the MCM-41-type hosting polymers,6 noble metals,7 and semiconductors such as gallium nitride8 have been prepared successfully. ... 29,30 These precursors are characterized by low thermolysis temperatures and high solubility in aprotic solvents. ... Because the porous silica materials were carefully dried in a vacuum at 150 C for 24 h, it is rather unlikely that this hydrolysis results from water adsorbed in the pore system. ...

S. Polarz; F. Neues; M. W. E. van den Berg; W. Grnert; L. Khodeir

2005-08-06T23:59:59.000Z

124

Cation Geothermometers At Lightning Dock Geothermal Area (Witcher...  

Open Energy Info (EERE)

Number DE-FC07-00AL66977 Notes This project deepened a well and took 4 samples from wells around the Lightning Docks KGRA and performed extensive chamical and isotope analysis...

125

Hybrid Lattice Boltzmann/Finite Difference simulations of viscoelastic multicomponent flows in confined geometries  

E-Print Network (OSTI)

We propose numerical simulations of viscoelastic fluids based on a hybrid algorithm combining Lattice-Boltzmann models (LBM) and Finite Differences (FD) schemes, the former used to model the macroscopic hydrodynamic equations, and the latter used to model the polymer dynamics. The kinetics of the polymers is introduced using constitutive equations for viscoelastic fluids with finitely extensible non-linear elastic dumbbells with Peterlin's closure (FENE-P). The numerical model is first benchmarked by characterizing the rheological behaviour of dilute homogeneous solutions in various configurations, including steady shear, elongational flows, transient shear and oscillatory flows. As an upgrade of complexity, we study the model in presence of non-ideal multicomponent interfaces, where immiscibility is introduced in the LBM description using the "Shan-Chen" model. The problem of a confined viscoelastic (Newtonian) droplet in a Newtonian (viscoelastic) matrix under simple shear is investigated and numerical resu...

Gupta, A; Scagliarini, A

2014-01-01T23:59:59.000Z

126

Mass separation of a multicomponent plasma flow in a curvilinear magnetic field  

SciTech Connect

The motion of a metal plasma flow of a vacuum-arc discharge in a transportation plasma-optical system with a curvilinear magnetic field is studied experimentally and numerically. The flow position at the output of the system is shown to depend on the cathode material, which determines the mass-to-charge ratio of plasma ions. As a result, the flow with a greater ion mass-to-charge ratio moves along a trajectory with a larger radius. A similar effect is observed in the case of a multicomponent plasma flow generated by a composite cathode. The results of two-fluid MHD simulations of a plasma flow propagating in a curvilinear magnetic field agree qualitatively with the experimental data.

Papernyi, V. L.; Krasov, V. I. [Irkutsk State University (Russian Federation)

2011-11-15T23:59:59.000Z

127

Diagonalization of multicomponent wave equations with a Born-Oppenheimer example  

Science Journals Connector (OSTI)

A general method to decouple multicomponent linear wave equations is presented. First, the Weyl calculus is used to transform operator relations into relations between c-number valued matrices. Then it is shown that the symbol representing the wave operator can be diagonalized systematically up to arbitrary order in an appropriate expansion parameter. After transforming the symbols back to operators, the original problem is reduced to solving a set of linear uncoupled scalar wave equations. The procedure is exemplified for a particle with a Born-Oppenheimer-type Hamiltonian valid through second order in ?. The resulting effective scalar Hamiltonians are seen to contain an additional velocity-dependent potential. This contribution has not been reported in recent studies investigating the adiabatic motion of a neutral particle moving in an inhomogeneous magnetic field. Finally, the relation of the general method to standard quantum-mechanical perturbation theory is discussed.

Stefan Weigert and Robert G. Littlejohn

1993-05-01T23:59:59.000Z

128

Coupling Multi-Component Models with MPH on Distributed MemoryComputer Architectures  

SciTech Connect

A growing trend in developing large and complex applications on today's Teraflop scale computers is to integrate stand-alone and/or semi-independent program components into a comprehensive simulation package. One example is the Community Climate System Model which consists of atmosphere, ocean, land-surface and sea-ice components. Each component is semi-independent and has been developed at a different institution. We study how this multi-component, multi-executable application can run effectively on distributed memory architectures. For the first time, we clearly identify five effective execution modes and develop the MPH library to support application development utilizing these modes. MPH performs component-name registration, resource allocation and initial component handshaking in a flexible way.

He, Yun; Ding, Chris

2005-03-24T23:59:59.000Z

129

Silica recovery and control in Hawaiian geothermal fluids  

SciTech Connect

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.

1992-06-01T23:59:59.000Z

130

Silica recovery and control in Hawaiian geothermal fluids. Final report  

SciTech Connect

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.

1992-06-01T23:59:59.000Z

131

Analysis of Substrate Access to Active Sites in Bacterial Multicomponent Monooxygenase Hydroxylases: X-Ray Crystal Structure of Xenon-Pressurized Phenol Hydroxylase from Pseudomonas Sp Ox1  

E-Print Network (OSTI)

In all structurally characterized bacterial multicomponent monooxygenase (BMM) hydroxylase proteins, a series of hydrophobic cavities in the ?-subunit trace a conserved path from the protein exterior to the carboxylate-bridged ...

McCormick, Michael S.

132

Molecular oxygen sensors based on photoluminescent silica aerogels  

NLE Websites -- All DOE Office Websites (Extended Search)

Molecular oxygen sensors based on photoluminescent silica aerogels Molecular oxygen sensors based on photoluminescent silica aerogels Title Molecular oxygen sensors based on photoluminescent silica aerogels Publication Type Journal Article Year of Publication 1998 Authors Ayers, Michael R., and Arlon J. Hunt Journal Journal of Non-Crystalline Solids Volume 225 Pagination 343-347 Keywords aerogel, air pressure, oxygen concentration, oxygen molecules, photoluminescence Abstract Photoluminescent silica aerogel acts as the active element of an optical sensor for molecular oxygen. The luminescent aerogel is prepared by the action of energized reducing gases on a standard silica aerogel. Intensity of aerogel photoluminescence decreases as the collision frequency between oxygen molecules and the luminescent carriers in the aerogel matrix increases. This behavior is a characteristic of many photoluminescent materials and arises from a transfer of energy from the aerogel to surrounding oxygen molecules. A sensor for oxygen concentration or air pressure can therefore be simply constructed utilizing an ultraviolet source for excitation and a suitable detector for the emitted visible signal. Stern-Volmer quenching constants for the aerogel sensing element are 1.55×10-2 Torr-1 for hydrophilic aerogel and 2.4×10-3 Torr-1 for hydrophobic aerogel.

133

Surface characterization of silica glass substrates treated by atomic hydrogen  

SciTech Connect

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: masuno@iis.u-tokyo.ac.jp [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)

2013-12-15T23:59:59.000Z

134

Silica membranes for hydrogen separation from coal gas. Final report  

SciTech Connect

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.

1996-01-01T23:59:59.000Z

135

Potassium geopolymer foams made with silica fume pore forming agent for thermal insulation  

Science Journals Connector (OSTI)

Porous potassium based geopolymers with a mutli-scale porosity were synthesized. Silica fume is introduced as an additive to the geopolymer formulation. The free silicon contained inside this silica fume is ox...

Joseph Henon; Arnaud Alzina; Joseph Absi

2013-02-01T23:59:59.000Z

136

Self-Assembled Multi-Component Catenanes: The Effect of Multivalency and Cooperativity on Structure and Stability  

Science Journals Connector (OSTI)

Self-Assembled Multi-Component Catenanes: The Effect of Multivalency and Cooperativity on Structure and Stability ... Using dynamic combinatorial chemistry, mixtures of dipeptide monomers were combined to probe how the structural elements of a family of self-assembled [2]-catenanes affect their equilibrium stability versus competing non-catenated structures. ... The nanostructure is constructed through the self-assembly of the ?-helical building block excised from E. coli galactoside acetyltransferase (PDB code 1krr, chain A; residues 131-165). ...

Mee-Kyung Chung; Stephen J. Lee; Marcey L. Waters; Michel R. Gagn

2012-06-11T23:59:59.000Z

137

Self-Assembled Multi-Component Catenanes: Structural Insights into an Adaptable Class of Molecular Receptors and [2]-Catenanes  

Science Journals Connector (OSTI)

Self-Assembled Multi-Component Catenanes: Structural Insights into an Adaptable Class of Molecular Receptors and [2]-Catenanes ... The self-assembly of complex structures from simple building blocks is a general principle that can lead to significant gains in structure and function. ... The family of catenanes can be described as flower-like with a compact core where the aryl of the arylglycine is pinched between two loops of the saddle-shaped tetrameric ring (Figure 1). ...

Mee-Kyung Chung; Peter S. White; Stephen J. Lee; Marcey L. Waters; Michel R. Gagn

2012-06-11T23:59:59.000Z

138

Reinforcement of Silica Aerogels Using Silane-End-Capped Polyurethanes  

Science Journals Connector (OSTI)

Such means of reinforcement may also result in nonuniform coating of the silica network by the polymer due to an imbalance of the rate of cross-linking reactions and the rate of molecular diffusion of polymer chains inside the gel network. ... Figure 3. SEM image of TA-PU-50 aerogel (modified with 50 wt % polymer II) showing polymer-coated silica particles. ... The presence of these polymer coatings in the aerogel structure was assumed as the origin of the high contact angle and their stressstrain curve similar to soft materials. ...

Yannan Duan; Sadhan C. Jana; Bimala Lama; Matthew P. Espe

2013-04-23T23:59:59.000Z

139

Hierarchical Silica Nanostructures Inspired by Diatom Algae Yield Superior Deformability, Toughness, and Strength  

E-Print Network (OSTI)

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.

140

Tailoring Elastic Properties of Silica Aerogels Cross-Linked with Polystyrene  

Science Journals Connector (OSTI)

The effect of incorporating an organic linking group, 1,6-bis(trimethoxysilyl)hexane (BTMSH), into the underlying silica structure of a styrene cross-linked silica aerogel is examined. ... Silica aerogels with their low density and thermal conductivity are potential candidates for various thermal, optical, and acoustic applications for aerospace including multipurpose structures for vehicles, space suits, and habitats (1). ...

Baochau N. Nguyen; Mary Ann B. Meador; Marissa E. Tousley; Brian Shonkwiler; Linda McCorkle; Daniel A. Scheiman; Anna Palczer

2009-02-19T23:59:59.000Z

Note: This page contains sample records for the topic "multicomponent geothermometers silica" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

HYDROGEOCHEM: A coupled model of HYDROlogic transport and GEOCHEMical equilibria in reactive multicomponent systems  

SciTech Connect

This report presents the development of a hydrogeochemical transport model for multicomponent systems. The model is designed for applications to proper hydrological setting, accommodation of complete suite of geochemical equilibrium processes, easy extension to deal with chemical kinetics, and least constraints of computer resources. The hydrological environment to which the model can be applied is the heterogeneous, anisotropic, saturated-unsaturated subsurface media under either transient or steady state flow conditions. The geochemical equilibrium processes included in the model are aqueous complexation, adsorption-desorption, ion exchange, precipitation-dissolution, redox, and acid-base reactions. To achieve the inclusion of the full complement of these geochemical processes, total analytical concentrations of all chemical components are chosen as the primary dependent variables in the hydrological transport equations. Attendant benefits of this choice are to make the extension of the model to deal with kinetics of adsorption-desorption, ion exchange, precipitation-dissolution, and redox relatively easy. To make the negative concentrations during the iteration between the hydrological transport and geochemical equilibrium least likely, an implicit form of transport equations are proposed. To alleviate severe constraints of computer resources in terms of central processing unit (CPU) time and CPU memory, various optional numerical schemes are incorporated in the model. The model consists of a hydrological transport module and geochemical equilibrium module. Both modules were thoroughly tested in code consistency and were found to yield plausible results. The model is verified with ten examples. 79 refs., 21 figs., 17 tabs.

Yeh, G.T.; Tripathi, V.S.

1990-11-01T23:59:59.000Z

142

Modeling phase transitions during the crystallization of a multicomponent fat under shear  

Science Journals Connector (OSTI)

The crystallization of multicomponent systems involves several competing physicochemical processes that depend on composition, temperature profiles, and shear rates applied. Research on these mechanisms is necessary in order to understand how natural materials form crystalline structures. Palm oil was crystallized in a Couette cell at 17 and 22C under shear rates ranging from 0to2880s?1 at a synchrotron beamline. Two-dimensional x-ray diffraction patterns were captured at short time intervals during the crystallization process. Radial analysis of these patterns showed shear-induced acceleration of the phase transition from ? to ??. This effect can be explained by a simple model where the ? phase nucleates from the melt, a process which occurs independently of shear rate. The ? phase grows according to an Avrami growth model. The ?? phase nucleates on the ? crystallites, with the amount of ?? crystal formation dependent on the rate of transformation of ? to ?? as well as the growth rate of the ?? phase from the melt. The shear induced ?-?? phase transition acceleration occurs because under shear, the ? nuclei form many distinct small crystallites which can easily transform to the ?? form, while at lower shear rates, the ? nuclei tend to aggregate, thus retarding the nucleation of the ?? crystals. The displacement of the diffraction peak positions revealed that increased shear rate promotes the crystallization of the higher melting fraction, affecting the composition of the crystallites. Crystalline orientation was observed only at shear rates above 180s?1 at 17C and 720s?1 at 22C.

Gianfranco Mazzanti; Alejandro G. Marangoni; Stefan H. J. Idziak

2005-04-25T23:59:59.000Z

143

Mechanized Silica Nanoparticles: A New Frontier in Theranostic Nanomedicine  

Science Journals Connector (OSTI)

Mechanized Silica Nanoparticles: A New Frontier in Theranostic Nanomedicine ... This article is part of the Theranostic Nanomedicine special issue. ... With the growth of nanomedicine, one can envisage the possibility of fabricating a theranostic vector that could release powerful therapeutics and diagnostic markers simultaneously and selectively to diseased tissue. ...

Michael W. Ambrogio; Courtney R. Thomas; Yan-Li Zhao; Jeffrey I. Zink; J. Fraser Stoddart

2011-06-15T23:59:59.000Z

144

Coagulation chemistries for silica removal from cooling tower water.  

SciTech Connect

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

2010-02-01T23:59:59.000Z

145

Atmospheric Plasma Deposited Dense Silica Coatings on Plastics  

Science Journals Connector (OSTI)

Atmospheric Plasma Deposited Dense Silica Coatings on Plastics ... (8) Finally, some plasma techniques including atmospheric plasmas work at low gas temperature, are suitable for treating plastics with low glass transition temperatures, and can even be used on biological samples. ... These results suggest that the mechanism in the atm.-pressure plasma is the same as that in low-pressure plasmas. ...

Linying Cui; Alpana N. Ranade; Marvi A. Matos; Liam S. Pingree; Theo J. Frot; Geraud Dubois; Reinhold H. Dauskardt

2012-11-26T23:59:59.000Z

146

Silica-Supported Tantalum Clusters: Catalyst for Alkane Conversion  

SciTech Connect

Silica-supported tantalum clusters (on average, approximately tritantalum) were formed by the treatment, in either H{sub 2} or ethane, of adsorbed Ta(CH{sub 2}Ph){sub 5}; the supported catalyst is active for ethane conversion to methane and propane at 523 K, with the used catalyst containing clusters of the same average nuclearity as the precursor.

Nemana ,S.; Gates, B.

2006-01-01T23:59:59.000Z

147

Fabrication of magnetite/silica/titania core-shell nanoparticles  

Science Journals Connector (OSTI)

Fe3O4/SiO2/TiO2 core-shell nanoparticles were synthesized via a sol-gel method with the aid of sonication. Fe3O4 nanoparticles were being encapsulated within discrete silica nanospheres, ...

Suh Cem Pang; Sze Yun Kho; Suk Fun Chin

2012-01-01T23:59:59.000Z

148

Formation of Hollow Gallium Nitride Spheres via Silica Sphere Templates  

Science Journals Connector (OSTI)

Formation of Hollow Gallium Nitride Spheres via Silica Sphere Templates ... To form reasonably uniform gallium oxide shells, the amounts of urea and water added to the reaction mixture were varied. ... Due to the low solubility of urea in 2-propanol, addition of a larger amount of urea than that used in this study is not desirable. ...

Chun-Neng Lin; Michael H. Huang

2008-12-30T23:59:59.000Z

149

Moisture Transport in Silica Gel Packed Beds: II. Experimental Study  

SciTech Connect

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.

1986-08-01T23:59:59.000Z

150

Surface Aggregate Structure of Nonionic Surfactants on Silica Nanoparticles  

E-Print Network (OSTI)

against flat solid surfaces has been gained mainly by neutron reflectometry (NR)1,2,4 and atomic force light scattering and small-angle neutron scattering (SANS) using a H2O/D2O mixture matching the silica

Paris-Sud XI, Université de

151

INSTRUMENTS-METHODS-36 Absorption and scattering lengths of high density silica aerogels with n = 1.07  

E-Print Network (OSTI)

angles could be the use of silica aerogels as radiator. Simultaneously, an aerogel ?erenkov counter is

L. Debenjak; P. Achenbach; J. Pochodzalla; T. Saito

152

Vaporization modeling of petroleum-biofuel drops using a hybrid multi-component approach  

SciTech Connect

Numerical modeling of the vaporization characteristics of multi-component fuel mixtures is performed in this study. The fuel mixtures studied include those of binary components, biodiesel, diesel-biodiesel, and gasoline-ethanol. The use of biofuels has become increasingly important for reasons of environmental sustainability. Biofuels are often blended with petroleum fuels, and the detailed understanding of the vaporization process is essential to designing a clean and efficient combustion system. In this study, a hybrid vaporization model is developed that uses continuous thermodynamics to describe petroleum fuels and discrete components to represent biofuels. The model is validated using the experimental data of n-heptane, n-heptane-n-decane mixture, and biodiesel. Since biodiesel properties are not universal due to the variation in feedstock, methods for predicting biodiesel properties based on the five dominant fatty acid components are introduced. Good levels of agreement in the predicted and measured drop size histories are obtained. Furthermore, in modeling the diesel-biodiesel drop, results show that the drop lifetime increases with the biodiesel concentration in the blend. During vaporization, only the lighter components of diesel fuel vaporize at the beginning. Biodiesel components do not vaporize until some time during the vaporization process. On the other hand, results of gasoline-ethanol drops indicate that both fuels start to vaporize once the process begins. At the beginning, the lighter components of gasoline have a slightly higher vaporization rate than ethanol. After a certain time, ethanol vaporizes faster than the remaining gasoline components. At the end, the drop reduces to a regular gasoline drop with heavier components. Overall, the drop lifetime increases as the concentration of ethanol increases in the drop due to the higher latent heat. (author)

Zhang, Lei; Kong, Song-Charng [Department of Mechanical Engineering, Iowa State University, 2025 Black Engineering Building, Ames, IA 50011 (United States)

2010-11-15T23:59:59.000Z

153

1 LOST PRODUCTION AS CONSEQUENSE OF SILICA SCALING IN CERRO  

E-Print Network (OSTI)

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; Daz Sara; Lilia Moya; Jess De; Len Vivar

154

Silica aerogels modified by functional and nonfunctional organic groups  

SciTech Connect

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)

1996-12-31T23:59:59.000Z

155

Nimesulide adsorbed on silica aerogel using supercritical carbon dioxide  

Science Journals Connector (OSTI)

Silica aerogel (SA) was loaded with nimesulide, a drug model compound, to demonstrate the potentiality of adsorption processes based on the usage of supercritical carbon dioxide to treat poorly water-soluble drugs, forming new kinds of drug delivery systems. Adsorption isotherms and kinetics were measured and described by models. The effect of pressure, temperature and solution concentration on loaded SA were also studied. Modelling of kinetic data showed that the sorption process was best described by a pseudo-second-order model. The adsorption isotherm data were best fitted by the Freundlich isotherm. The drug/SA composites were characterized using scanning electron microscopy, X-ray microanalysis, and FT-IR. Release kinetics of the adsorbed drug were also evaluated by in vitro dissolution tests. Results showed that nimesulide can be uniformly dispersed into the aerogel and that the release rate of nimesulide from the composite, constituted by drug and silica aerogel, is much faster than that of the crystalline drug.

Giuseppe Caputo; Mariarosa Scognamiglio; Iolanda De Marco

2012-01-01T23:59:59.000Z

156

Fluorescent Functionalized Mesoporous Silica for Radioactive Material Extraction  

SciTech Connect

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

2012-08-01T23:59:59.000Z

157

Supercritical carbon dioxide behavior in porous silica aerogel  

SciTech Connect

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

2011-01-01T23:59:59.000Z

158

Silica microparticles precipitation by two processes using supercritical fluids  

Science Journals Connector (OSTI)

Silica microspheres are of great interest for several applications in areas such as medicine, biochemistry, colloidal chemistry and aerosol research. In this work, the solgel method was used to obtain such microparticles in two different ways. One of the methods applied was supercritical reaction; a high temperature process using ethanol as a supercritical fluid (SCF reaction). Another approach to obtaining silica microparticles was Supercritical AntiSolvent (SAS) process, as a low temperature process, using supercritical carbon dioxide (scCO2). A tetraethyl orthosilicate (TEOS) and water solution (1:4 molar ratio) was dissolved in ethanol and then pumped into an autoclave at 100bar and 523K for the SCF reaction process, and at 120bar and 313K in the case of the SAS process. All the experiments led to a successful precipitation of silica microparticles, in the micrometer range. In all cases spherical morphology and no agglomeration was found. Furthermore, the main textural characteristics of such powders were obtained by nitrogen physisorption experiments. Results reveal spherical microparticles with nanopores smaller than 1nm in size when using supercritical ethanol, and bulky microparticles with smooth surfaces when using scCO2.

A. Montes; M.D. Gordillo; C. Pereyra; N. de la Rosa-Fox; E.J. Martnez de la Ossa

2013-01-01T23:59:59.000Z

159

Multimodality Imaging with Silica-Based Targeted Nanoparticle Platforms  

SciTech Connect

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

2012-04-09T23:59:59.000Z

160

Aerosol synthesis of macroporous silica adsorbents with high performance in paclitaxel purification from plant cell cultures  

Science Journals Connector (OSTI)

Abstract Macroporous spherical silica particles having high performance for the purification of paclitaxel were synthesized by spray pyrolysis using polystyrene nanoparticles as a template. In terms of increasing the purity and yield of paclitaxel, the synthesized macroporous silica showed the better performance than mesoporous silica of high surface area as well as commercial sylopute. The generation of macroporous with the sacrifice of losing surface area was proved to be helpful for enhancing the performance of adsorbents for paclitaxel purification. As a result, the high purity (67.3%) and yield (80.0%) of paclitaxel was achieved by using macroporous silica prepared by spray pyrolysis.

Hye Ran Jang; Jin-Hyun Kim; Kyeong Youl Jung

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "multicomponent geothermometers silica" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Polymer reinforced aerogels and composites A. Polyimide crosslinked aerogels B. Silica-polymethylmethacrylate composites .  

E-Print Network (OSTI)

??"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-

2008-01-01T23:59:59.000Z

162

Extensional rheology of shear-thickening fumed silica nanoparticles dispersed in an aqueous polyethylene  

E-Print Network (OSTI)

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

163

E-Print Network 3.0 - ash slag silica Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

Engineering ; Materials Science 91 By-Products Utilization Summary: pozzolans include coal fly ash, blast furnace slag, silica fume, and other combustion ashes. When...

164

Silica banding in the deep-sea lithistid sponge Corallistes undulatus ...  

Science Journals Connector (OSTI)

The ?14C results for organic carbon trapped in the silica desmas, deposited after the 1960s, supports this assertion; only a small atmospheric nuclear weapons...

165

Lab Trials of an Electricity Transmission Line Voltage Sensor Based on Thermally Poled Silica Fibre  

Science Journals Connector (OSTI)

Voltage sensing using helically coiled lengths of thermally poled twin-hole silica optical fibre is presented. Lab accuracy test results showing good linearity and signal to noise...

Michie, Andrew M; Hambley, Philip; Bassett, Ian M; Haywood, John H; Henry, Peter; Ingram, John

166

Improving the Performance of Heat Insulation Polyurethane Foams by Silica Nanoparticles  

Science Journals Connector (OSTI)

Heat insulation polyurethane foam materials were doped by silica nano particles, ... , thermal and mechanical properties of polyurethane rigid foam were investigated. Thermal and mechanical properties were...

M. M. Alavi Nikje; A. Bagheri Garmarudi; M. Haghshenas

2009-01-01T23:59:59.000Z

167

Evaluation of concrete structures affected by alkali-silica reaction and delayed ettringite formation.  

E-Print Network (OSTI)

??Alkali-silica reaction (ASR) and delayed ettringite formation (DEF) are expansive reactions that can lead to the premature deterioration of concrete structures. Both have been implicated (more)

Giannini, Eric Richard

2012-01-01T23:59:59.000Z

168

Nondestructive evaluation of reinforced concrete structures affected by alkali-silica reaction and delayed ettringite formation.  

E-Print Network (OSTI)

??Alkali-silica reaction (ASR) and delayed ettringite formation (DEF) deterioration have been a problem for the concrete infrastructure in the state of Texas and around the (more)

Kreitman, Kerry Lynn

2011-01-01T23:59:59.000Z

169

Accelerated test methods for evaluating alkali-silica reactivity of recycled concrete aggregates.  

E-Print Network (OSTI)

??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)

2011-01-01T23:59:59.000Z

170

Thermal annealing of laser damage precursors on fused silica surfaces  

SciTech Connect

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

2012-03-19T23:59:59.000Z

171

Chemical treatment for silica-containing glass surfaces  

DOE Patents (OSTI)

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.

1998-04-07T23:59:59.000Z

172

Chemical treatment for silica-containing glass surfaces  

DOE Patents (OSTI)

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 (Cedar Crest, NM); Smith, William Larry (Albuquerque, NM)

1998-01-01T23:59:59.000Z

173

Chemical treatment for silica-containing glass surfaces  

DOE Patents (OSTI)

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)

1999-01-01T23:59:59.000Z

174

Chemical treatment for silica-containing glass surfaces  

DOE Patents (OSTI)

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 (Cedar Crest, NM); Smith, William Larry (Albuquerque, NM)

1999-01-01T23:59:59.000Z

175

Cooling rate and size effects on the medium-range structure of multicomponent oxide glasses simulated by molecular dynamics  

SciTech Connect

A set of molecular dynamics simulations were performed to investigate the effect of cooling rate and system size on the medium-range structure of melt-derived multicomponent silicate glasses, represented by the quaternary 45S5 Bioglass composition. Given the significant impact of the glass degradation on applications of these materials in biomedicine and nuclear waste disposal, bulk structural features which directly affect the glass dissolution process are of particular interest. Connectivity of the silicate matrix, ion clustering and nanosegregation, distribution of ring and chain structural patterns represent critical features in this context, which can be directly extracted from the models. A key issue is represented by the effect of the computational approach on the corresponding glass models, especially in light of recent indications questioning the suitability of conventional MD approaches (that is, involving melt-and-quench of systems containing ?10{sup 3} atoms at cooling rates of 5-10 K/ps) when applied to model these glasses. The analysis presented here compares MD models obtained with conventional and nonconventional cooling rates and system sizes, highlighting the trend and range of convergence of specific structural features in the medium range. The present results show that time-consuming computational approaches involving much lower cooling rates and/or significantly larger system sizes are in most cases not necessary in order to obtain a reliable description of the medium-range structure of multicomponent glasses. We identify the convergence range for specific properties and use them to discuss models of several glass compositions for which a possible influence of cooling-rate or size effects had been previously hypothesized. The trends highlighted here represent an important reference to obtain reliable models of multicomponent glasses and extract converged medium-range structural features which affect the glass degradation and thus their application in different fields. In addition, as a first application of the present findings, the fully converged structure of the 45S5 glass was further analyzed to shed new light on several dissolution-related features whose interpretation has been rather controversial in the past.

Tilocca, Antonio [Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ (United Kingdom)] [Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ (United Kingdom)

2013-09-21T23:59:59.000Z

176

Stress dependent activation entropy for dynamic fatigue of pristine silica optical fibers  

E-Print Network (OSTI)

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

177

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. Pinnavaia and coworkers6 have reported the synthesis of MSU-X mesoporous materials with several non- ionic and cowork- ers7 have reported the synthesis of SBA mesoporous silica materials, which have well

Kim, Ji Man

178

Glycine and lysine adsorption and reactivity on the surface of amorphous silica  

Science Journals Connector (OSTI)

...J., Fricke, J. (1997): Raman spectroscopy on silica aerogels. J. Non-Cryst. Solids , 120 , 294-298. Rimola, A...J., Fricke, J. (1997): Raman spectroscopy on silica aerogels. J. Non-Cryst. Solids, 120, 294-298. Rimola, A...

Lorenzo Stievano; Ling Yu Piao; Irne Lopes; Ming Meng; Dominique Costa; Jean-Franois Lambert

179

Hybrid Silica-PVA Nanofibers via Sol-Gel Electrospinning Tahira Pirzada,,  

E-Print Network (OSTI)

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.

180

Integrated Optical Orbital Angular Momentum Multiplexing Device using 3-D Waveguides and a Silica PLC  

E-Print Network (OSTI)

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

Note: This page contains sample records for the topic "multicomponent geothermometers silica" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Friction and Heat Transfer Characteristics of Silica and CNT Nanofluids in a Tube Flow  

E-Print Network (OSTI)

Friction and Heat Transfer Characteristics of Silica and CNT Nanofluids in a Tube Flow MILIVOJE M@niu.edu * 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.

182

Sorption and Diffusion of Simple Paraffins in Silica-Alumina Cracking Catalyst  

Science Journals Connector (OSTI)

...Paraffins in Silica-Alumina Cracking Catalyst R. M. Barrer T. Gabor Sorption and...propane in the silica-alumina cracking catalyst previously employed in similar measurements...behaviour in the micropore structure of the catalyst, for the species studied. The ratio...

1960-01-01T23:59:59.000Z

183

Molten Gallium as a Catalyst for the Large-Scale Growth of Highly Aligned Silica Nanowires  

E-Print Network (OSTI)

Molten Gallium as a Catalyst for the Large-Scale Growth of Highly Aligned Silica Nanowires Zheng a small size (5-100 nm in diameter), high melting point metal (such as gold and iron) catalyst particle as an effective catalyst for the large-scale growth of highly aligned, closely packed silica nanowire bunches

Wang, Zhong L.

184

Ethylenediamine at Air/Liquid and Air/Silica Interfaces: Protonation  

E-Print Network (OSTI)

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

185

Developing a process for commercial silica production from Salton Sea brines  

SciTech Connect

The goal of this joint LLNL-CalEnergy project is to develop a method for precipitating marketable silica from spent Salton Sea Geothermal Field (SSGF) brines. Many markets for silica exist. We have initially targeted production of silica as a rubber additive. Silica reinforced rubber gives tires less rolling resistance, greater tear strength, and better adhesion to steel belts. Previous silica precipitates produced by CalEnergy from Salton Sea brines were not suitable as rubber additives. They did not to disperse well in the rubber precursors and produced inferior rubber. CalEnergy currently minimizes silica scaling in some of their production facilities by acidifying the brine pH. The rate of silica precipitation slows down as the pH is lowered, so that energy extraction and brine reinfection are possible without unacceptable amounts of scaling even with more than 700 ppm SiO{sub 2} in solution. We are adding a step in which a small amount of base is added to the acidified brine to precipitate silica before reinfection. By carefully controlling the type, rate, and amount of base addition, we can optimize the properties of the precipitate to approach those of an ideal rubber additive.

Bourcier, W; McCutcheon, M; Leif, R; Bruton, C

2000-09-25T23:59:59.000Z

186

Modulating DNA adsorption on silica beads using an electrical switchw Oren Z. Gallb  

E-Print Network (OSTI)

use electrolysis of water to alter pH in a packed bed of silica beads and switch the silica bead electrolysis of water.20,21 The two gold electrodes (200 mm wide) were 1000 mm apart from each other, higher voltage introduces more electrolysis of water which changes the pH more rapidly. However, we found

Lu, Chang

187

The onset of optical breakdown in KrF-laser-irradiated silica glass surfaces  

E-Print Network (OSTI)

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

188

The effect of silica nanoparticle-modified surfaces on cell morphology, cytoskeletal organization and function  

E-Print Network (OSTI)

The effect of silica nanoparticle-modified surfaces on cell morphology, cytoskeletal organization investigate the effect of nanoparticle (NP) assemblies arranged on a flat substrate on cytoskeletal substrates were coated with monodispersed silica nanoparticles of 50, 100 and 300 nm in diameter. The impact

189

Surface Analysis of Silica Gel Particles after Mechanical Dry Coating with Magnesium Stearate  

E-Print Network (OSTI)

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

Paris-Sud XI, Université de

190

DENSIFICATION AS THE ONLY MECHANISM AT STAKE DURING INDENTATION OF SILICA GLASS?  

E-Print Network (OSTI)

DENSIFICATION AS THE ONLY MECHANISM AT STAKE DURING INDENTATION OF SILICA GLASS? Vincent Keryvin1 mariette.nivard@univ-rennes1.fr, f jean-christophe.sangleboeuf@univ-rennes1.fr Keywords: Indentation; Glass; Densification; Plasticity; Imprint; Modeling; Finite-Element Analysis; Fused quartz Abstract. Silica glass

Brest, Université de

191

IUPAC-NIST Solubility Data Series. 77. C 2+ Nitroalkanes With Water or Organic Solvents: Binary and Multicomponent Systems  

Science Journals Connector (OSTI)

The mutual solubilities and liquid-liquid equilibria of binary and multicomponent systems composed of C 2+ nitroalkanes with solvents are reviewed. The solvents (mainly in liquid phase) include water inorganic compounds and a variety of organic compounds such as hydrocarbons halogenated hydrocarbons alcohols acids esters and nitrogen compounds. A total 81 binary 21 ternary 2 quaternary and 1 five component systems whose properties were described in the chemical literature through 1998 are compiled. For 14 systems sufficient data were available to allow critical evaluation. All data are expressed as mass and mole fractions as well as the originally reported units. Similar reviews of gas liquid and solid solubilities for other systems have been within the Solubility Data Series. This is volume 77 of this series.

Valerii P. Sazonov; David G. Shaw

2002-01-01T23:59:59.000Z

192

Geometrical and kinetic isotope effects on SN2 chemical reactions using multi-component molecular orbital method  

Science Journals Connector (OSTI)

To estimate the kinetic isotope effect (KIE) for nucleophilic substitution (SN2) reaction, F?+CH4?CH3F+H?, and deuterated ones, we have considered the geometrical isotope effect (GIE) induced by the difference of the protonic and deuteronic wavefunctions using the multi-component molecular orbital (MC_MO) method. By replacing protons with deuterons, the CD bond lengths are about 0.007 shorter than CH. We estimated the ratio ( k a H / k a D ) of rate constants based on MC_MO results. The geometrical and energetic differences between H and D compounds are induced by relaxation of electronic structures due to the difference in the wavefunctions of the proton and deuteron.

Yoko Kikuta; Takayoshi Ishimoto; Umpei Nagashima

2011-01-01T23:59:59.000Z

193

9 - Microporous silica membranes: fundamentals and applications in membrane reactors for hydrogen separation  

Science Journals Connector (OSTI)

Abstract: This chapter discusses the research and development of membrane reactors, incorporating microporous silica-based membranes, specifically for hydrogen production. Microporous silica membranes are first introduced alongside a discussion of relevant gas transport mechanisms, membrane performance parameters, membrane reactor designs and membrane reactor performance metrics. This is followed by an in-depth analysis of the various research investigations where silica membrane reactors have been used to produce hydrogen and/or syngas from hydrocarbon reforming reactions. Of particular importance here is the hydrothermal instability of silica-based membranes at the required operating temperatures and so the chapter closes by presenting the future research trends and industrial design challenges and considerations of silica-based membrane reactors.

S. Smart; J. Beltramini; J.C. Diniz da Costa; S.P. Katikaneni; T. Pham

2013-01-01T23:59:59.000Z

194

The \\{LHCb\\} RICH silica aerogel performance with LHC data  

Science Journals Connector (OSTI)

In the \\{LHCb\\} experiment 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 (1100GeV/c), two detectors with three Cherenkov radiators have been designed and installed. In the medium (1040GeV/c) and high (30100GeV/c) momentum ranges, gas radiators are used (C4F10 and CF4, respectively). In the low momentum range (110GeV/c), pion, kaon and proton separation is performed with solid silica aerogel radiator. A set of 16 tiles, with large transverse dimensions of up to 200 200 mm 2 and nominal refractive index 1.03 have been produced and integrated in the detector. These tiles have excellent optical properties and homogeneity of the refractive index at the percent level within the tile. The first data collected at the LHC are used to investigate the behaviour of the RICH; preliminary results of the performance of silica aerogel are presented and discussed.

D.L. Perego

2011-01-01T23:59:59.000Z

195

Macroscopic Subdivision of Silica Aerogel Collectors for Sample Return Missions  

SciTech Connect

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

2005-09-14T23:59:59.000Z

196

Low-temperature synthesis of AlN powder with multicomponent additive systems by carbothermal reduction-nitridation method  

SciTech Connect

AlN powders were synthesized at low temperatures (1300 and 1400 {sup o}C) by the carbothermal reduction-nitridation (CRN) method using multicomponent additive systems. The synthesis treatments were conducted in a graphite furnace with flowing nitrogen gas between 1200 and 1500 {sup o}C using powder mixtures with Al{sub 2}O{sub 3}:C molar ratio of 1:3 and 0.5-3 wt% of CaF{sub 2}, Y{sub 2}O{sub 3}, Li{sub 2}CO{sub 3} and/or SrCO{sub 3} as additives. In relation to the conventional CRN process, the use of multicomponent additive systems reduced the synthesis temperature in 200 {sup o}C (CaF{sub 2}-SrCO{sub 3}), 100 {sup o}C (CaF{sub 2}-Li{sub 2}CO{sub 3} and CaF{sub 2}-Y{sub 2}O{sub 3}-Li{sub 2}CO{sub 3}) or <100 {sup o}C (CaF{sub 2}-Y{sub 2}O{sub 3} and CaF{sub 2}-Y{sub 2}O{sub 3}-Li{sub 2}CO{sub 3}-SrCO{sub 3}). X-ray diffraction patterns showed that the additives reacted with the alumina powder forming aluminate phases, which vaporized with the increase of synthesis temperature. The enhanced AlN conversion rate was discussed in terms of the vaporization of aluminates in the reducing atmosphere.

Molisani, Andre Luiz [Federal University of ABC, Rua Santa Adelia, 166, Santo Andre, SP 09210-170 (Brazil)] [Federal University of ABC, Rua Santa Adelia, 166, Santo Andre, SP 09210-170 (Brazil); Yoshimura, Humberto Naoyuki, E-mail: humberto.yoshimura@ufabc.edu.br [Federal University of ABC, Rua Santa Adelia, 166, Santo Andre, SP 09210-170 (Brazil)

2010-06-15T23:59:59.000Z

197

Natural hydrous amorphous silica: Quantitation of network speciation and hydroxyl content by 29Si MAS NMR and vibrational spectroscopy  

Science Journals Connector (OSTI)

...included a volcanically derived silica coating on young basalt from Kilauea, Hawaii...sites, respectively. The Hawaiian silica coating and silicic acid samples displayed high...the structural Si-OH content of the coating was unusually high for a natural silica...

Steven M. Chemtob; George R. Rossman; Jonathan F. Stebbins

198

THE JOURNAL OF CHEMICAL PHYSICS 140, 224502 (2014) Search for a liquid-liquid critical point in models of silica  

E-Print Network (OSTI)

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

199

Aluminum and silica intake in drinking water and the risk of Alzheimer's disease or cognitive decline: findings of the  

E-Print Network (OSTI)

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

Paris-Sud XI, Université de

200

Preparation of Activated Carbon and Silica Particles from Rice Straw  

Science Journals Connector (OSTI)

Lignocellulosic biomass, such as agricultural crop residues, forestry byproducts, and municipal waste, is a rich source of renewable energy and materials. ... The LH powders were dried in oven at 60 C for 12 h, placed in a quartz tube (2 cm inner diameter), and then dried in a furnace (Mini-Mite, Lindberg/Blue) at 10 C/min to 105 C and held for 0.5 h. ... TEM samples were prepared by dispersing a small amount of AC and silica particles in water (?0.01 g/L) and sonicated (2510, Branson) for 60 min first, and then a drop of the sonicated suspension was placed onto a carbon grid and dried in air. ...

Sixiao Hu; You-Lo Hsieh

2014-02-21T23:59:59.000Z

Note: This page contains sample records for the topic "multicomponent geothermometers silica" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Hydrogen and oxygen adsorption stoichiometries on silica supported ruthenium nanoparticles  

SciTech Connect

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

2008-12-01T23:59:59.000Z

202

Use of silica waste from the Cerro Prieto geothermal field as construction material  

SciTech Connect

The Cerro Prieto geothermal field generates 620 MW of electric power and in the process produces 11,000 tonnes of brine per hour that is disposed of in surface ponds. Approximately 1300 tonnes of silica waste is the residual product from this hourly production of brine. At present, there is no use for this waste silica. Some experimental work has been undertaken by CFE to utilize this waste silica such as for surfacing roads with a cement-silica mixture and making bricks with various additives. However, none of this research has been documented. Approximately two years ago, a joint USDOE/CFE research project was proposed to investigate the use of the waste silica. The proposal included using the silica mixed with asphalt and cement to produce a suitable road surfacing material, and to combine the silica with various additives to be used as bricks for low cost housing. It was thought, that the low specific gravity of the silica and the proposed mixtures would give the bricks a high insulating value (low-thermal conductivity), thus protecting the residents from high solar heating, typical of Baja California and the area around Mexicali. Finally, since the geothermal fields of the area extend into the Imperial Valley of California where 420 MW of geothermal power is generated, it was hoped that this research would also be applicable to the U.S. side of the border. Some attempt has been made by UNOCAL at their Imperial Valley plant (now owned by Magma Power) to use the waste silica stabilized with cement for roads and dikes around the plant.

Lund, J.W.; Boyd, T.; Monnie, D.

1995-02-01T23:59:59.000Z

203

Studies of Immobilized Homogeneous Metal Catalysts on Silica Supports  

SciTech Connect

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

2003-05-31T23:59:59.000Z

204

Effect of Optical Coating and Surface Treatments on Mechanical Loss in Fused Silica  

E-Print Network (OSTI)

We report on the mechanical loss in fused silica samples with various surface treatments and compare them with samples having an optical coating. Mild surface treatments such as washing in detergent or acetone were not found to affect the mechanical loss of flame-drawn fused silica fibers stored in air. However, mechanical contact (with steel calipers) significantly increased the loss. The application of a high-reflective optical coating of the type used for the LIGO test masses was found to greatly increase the mechanical loss of commercially polished fused silica microscope slides. We discuss the implications for the noise budget of interferometers.

Andri M. Gretarsson; Gregory M. Harry; Steven D. Penn; Peter R. Saulson; John J. Schiller; William J. Startin

1999-11-17T23:59:59.000Z

205

The nonlinear optical, magnetic, and Mssbauer spectral properties of some iron(III) doped silica xerogels  

Science Journals Connector (OSTI)

Iron(III) species dispersed in silica have been ... synthesized with a sol-gel process. The iron(III) was introduced as the acetylacetonate complex into a solution of tetraethoxysilane to...Z-scan experimental st...

L. Rebbouh; V. Rosso; Y. Renotte; Y. Lion; F. Grandjean

2006-05-01T23:59:59.000Z

206

Effect of gel parameters on monolithicity and density of silica aerogels  

Science Journals Connector (OSTI)

As part of continuing investigation of the preparation and characterization of silica aerogels, detailed experimental results on monolithicity and density of the aerogels as a function of catalysts and their c...

A. Venkateswara Rao; N. N. Parvathy

1993-06-01T23:59:59.000Z

207

Synthesis and characterization of transparent silica-based aerogels using methyltrimethoxysilane precursor  

Science Journals Connector (OSTI)

Silica-based aerogels with high transparency and high bending strength were prepared using methyltrimethoxysilane and non-ionic surfactant under supercritical drying condition of CO2. Non-ionic surfactant, ethyle...

Masayuki Nogami; Shohei Hotta

2010-11-01T23:59:59.000Z

208

E-Print Network 3.0 - aperture fused silica Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

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...

209

E-Print Network 3.0 - ash-silica fume pastes Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

; 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...

210

Ammoniated silica-alumina gel and catalyst containing the same and processes for producing same  

SciTech Connect

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.

1980-12-09T23:59:59.000Z

211

Atmospheric Pressure Plasma Treatment of Fused Silica, Related Surface and Near-Surface Effects and Applications  

Science Journals Connector (OSTI)

We report on an atmospheric pressure plasma (APP) treatment of fused silica and its related surface and near-surface effects. Such treatment was performed in order to improve laser ... process gas was used. By th...

Christoph Gerhard; Tobias Weihs; Daniel Tasche

2013-10-01T23:59:59.000Z

212

Effects from Alkali-Silica Reacton and Delayed Ettringite Formation on Reinforced Concrete Column Lap Splices  

E-Print Network (OSTI)

Reinforced concrete bridge columns can deteriorate prematurely due to the alkali-silica reaction (ASR) and/or delayed ettringite formation (DEF), causing internal expansion and cracking on the surface of the concrete. The performance...

Eck, Mary

2012-07-16T23:59:59.000Z

213

Silica-nanoparticle-dispersed methacrylate photopolymers with net diffraction efficiency near 100%  

Science Journals Connector (OSTI)

We demonstrate volume holographic recording in silica-nanoparticle-dispersed methacrylate photopolymers with reduced scattering loss as low as 2%. This is made possible by use of 13-nm...

Suzuki, Naoaki; Tomita, Yasuo

2004-01-01T23:59:59.000Z

214

Method for inhibiting silica precipitation and scaling in geothermal flow systems  

DOE Patents (OSTI)

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.

1980-06-13T23:59:59.000Z

215

Effects from Alkali-Silica Reacton and Delayed Ettringite Formation on Reinforced Concrete Column Lap Splices.  

E-Print Network (OSTI)

??Reinforced concrete bridge columns can deteriorate prematurely due to the alkali-silica reaction (ASR) and/or delayed ettringite formation (DEF), causing internal expansion and cracking on the (more)

Eck, Mary

2012-01-01T23:59:59.000Z

216

E-Print Network 3.0 - alcali-silica reactions mechanisms Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

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,...

217

Time-resolved plasma measurements in Ge-doped silica exposed to infrared femtosecond laser  

SciTech Connect

Using a time-resolved interferometric technique, we study the laser-induced carrier-trapping dynamics in SiO{sub 2} and Ge-doped SiO{sub 2}. The fast trapping of electrons in the band gap is associated with the formation of self-trapped excitons (STE). The STE trapping is doping dependent in SiO{sub 2}. The mean trapping time of electrons excited in the conduction band was found to be significantly lower in Ge-doped silica (75 {+-} 5 fs) when compared to pure silica (155 {+-} 5 fs). At our concentration level, this indicates that the plasma properties are determined by the presence of easily ionizable states such as the presence of Ge atoms in the glass network. Therefore, we suggest that in Ge-doped silica there exist an additional trapping pathway that leads to a significantly faster excitons trapping and a higher plasma density when compared to undoped silica.

Lancry, M.; Poumellec, B. [LPCES/ICMMO, UMR CNRS-UPS 8182, Universite Paris Sud 11, Batiment 410, 91405 Orsay (France); Groothoff, N.; Canning, J. [Interdisciplinary Photonics Laboratories, School of Chemistry, University of Sydney, 206 NIC, ATP, Eveleigh, NSW, 1340 (Australia); Guizard, S.; Fedorov, N. [Laboratoire des Solides Irradies/CEA IRAMIS, Ecole Polytechnique, Palaiseau (France)

2011-12-15T23:59:59.000Z

218

Silica and acid-detergent fiber content of five varieties of bermudagrass  

E-Print Network (OSTI)

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

1971-01-01T23:59:59.000Z

219

Modifications in the correlation function in poly(vinyl alcohol)/silica hybrid wet gels  

Science Journals Connector (OSTI)

Small-angle X-ray scattering was used to study modifications in the correlation function in tetraethoxysilane-derived poly(vinyl alcohol)/silica hybrids. An additional scattering at low q was found to overlap the fundamental mass-fractal scattering from the basic silica. The fraction of both contributions to the total correlation function was estimated; this is the first time that such a study has been carried out for mass-fractal structures.

Vollet, D.R.

2008-11-28T23:59:59.000Z

220

The effect of lattice temperature on surface damage in fused silica optics  

SciTech Connect

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

2007-10-31T23:59:59.000Z

Note: This page contains sample records for the topic "multicomponent geothermometers silica" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Mineralogical characteristics of the silica polymorphs in relation to their biological activities  

SciTech Connect

Numerous aspects of minerals (including the silica polymorphs) can effect their biological activities. These include periodic structures, compositional variations, dissolution characteristics, surface properties, and particle size/shape. In order to understand mineral-induced pathogenesis in a mechanistic way, the links between these properties and biochemical processes must be elucidated. This paper presents some of the basic properties of the silica polymorphs that may relate to pathogenicity and mineralogical strategies for designing biological assays to evaluate these properties.

Guthrie, G.D. Jr. [Los Alamos National Lab., NM (United States); Heaney, P.J. [Princeton Univ., NJ (United States). Dept. of Geological and Geophysical Sciences

1993-10-01T23:59:59.000Z

222

Mean-field approach in the multi-component gas of interacting particles applied to relativistic heavy-ion collisions  

E-Print Network (OSTI)

Generalized mean-field approach for thermodynamic description of relativistic single- and multi-component gas in the grand canonical ensemble is formulated. In the framework of the proposed approach different phenomenological excluded-volume procedures are presented and compared to the existing ones. The mean-field approach is then used to effectively include hard-core repulsion in hadron-resonance gas model for description of chemical freeze-out in heavy-ion collisions. We calculate the collision energy dependence of several quantities for different values of hard-core hadron radius and for different excluded-volume procedures such as van der Waals and Carnahan-Starling models. It is shown that a choice of the excluded-volume model becomes important for large particle densities, and for large enough values of hadron radii ($r\\gtrsim0.9$ fm) there can be a sizable difference between different excluded-volume procedures used to describe the chemical freeze-out in heavy-ion collisions. For the smaller and more commonly used values of hard-core hadron radii ($r\\lesssim0.5$ fm) the van der Waals excluded-volume procedure is shown to be sufficient.

D. Anchishkin; V. Vovchenko

2015-01-23T23:59:59.000Z

223

Assistant template and co-template agents in modeling mesoporous silicas and post-synthesizing organofunctionalizations  

SciTech Connect

Mesoporous SBA-16 silicas were synthesized through a direct methodology using the template (F127) combined with co-templates (ethanol and n-butanol), with tetraethylorthosilicate as the silica source. These ordered mesoporous silica were characterized by elemental analyses, infrared spectroscopy, solid-state nuclear magnetic resonance for {sup 13}C (CP/MAS) and {sup 29}Si (HP/DEC) nuclei, nitrogen sorption/desorption processes, small angle X-ray analyses (SAXS) and transmission electron microscopy (TEM). SAXS and TEM results confirmed the space group Im3m and cubic 3D symmetry, typical for highly ordered SBA-16. The sorption/desorption data for SBA-16 and when functionalized gave type IV isotherms, with hysteresis loop H2. Surface areas of 836; 657 and 618 m{sup 2} g{sup -1} and average pore diameters of 7.99; 8.10 and 9.85 nm, for SBA-16A, SBA-16B and SBA-16C were obtained, respectively. When functionalized the silicas presented a reduction in surface area, pore volume and pore diameter due to the pendant chains that interfere with nitrogen sorption in these measurements. The co-template ethanol favors the ordered mesopores with highest wall thicknesses. - Graphical Abstract: The mesoporous SBA-16 can be synthesized from binary (F127/TEOS) or ternary (F127/alcohol/TEOs) systems to give well-ordered mesoporous silicas. The co-templates ethanol or butanol gave the final material with highest wall thickness, mainly with ethanol. After these syntheses the pores were successfully organofunctionalized to give a good incorporation of the silylating agents. The final silicas presented of well-arranged solid characteristics as expressing by three distinct peaks, as indexed by the corresponding planes. Highlights: Black-Right-Pointing-Pointer Syntheses of mesoporous silicas by using ternary (F127/agent/TEOS) and binary (F127/TEOS) systems. Black-Right-Pointing-Pointer Use of co-templates to synthesize mesoporous silicas with larger wall thicknesses. Black-Right-Pointing-Pointer Immobilization of pendant chains inside the porous silicas. Black-Right-Pointing-Pointer Ordered mesoposous silicas as new materials for possible applications on sorption and delivering drug systems.

Oliveira, Vaeudo V. [Institute of Chemistry, University of Campinas, UNICAMP, PO Box 6154, 13084-971 Campinas, SP (Brazil)] [Institute of Chemistry, University of Campinas, UNICAMP, PO Box 6154, 13084-971 Campinas, SP (Brazil); Airoldi, Claudio, E-mail: airoldi@iqm.unicamp.br [Institute of Chemistry, University of Campinas, UNICAMP, PO Box 6154, 13084-971 Campinas, SP (Brazil)] [Institute of Chemistry, University of Campinas, UNICAMP, PO Box 6154, 13084-971 Campinas, SP (Brazil)

2012-12-15T23:59:59.000Z

224

Photo-Alignment Behavior of Mesoporous Silica Thin Films Synthesized on a Photo-Cross-Linkable Polymer Film  

Science Journals Connector (OSTI)

Photo-Alignment Behavior of Mesoporous Silica Thin Films Synthesized on a Photo-Cross-Linkable Polymer Film ... Photo-aligning and micropatterning techniques for mesochannels of a silica thin film using a photo-cross-linkable polymer film with a cinnamoyl group are proposed. ... We propose herein a new photo-aligning and micropatterning technique for mesochannels of a silica thin film using a photo-cross-linkable polymer film with a cinnamoyl group. ...

Haruhiko Fukumoto; Shusaku Nagano; Nobuhiro Kawatsuki; Takahiro Seki

2006-02-11T23:59:59.000Z

225

Effect of silica on the properties of cellulose acetate/polyethylene glycol membranes for reverse osmosis  

Science Journals Connector (OSTI)

Abstract In this work, a series of cellulose acetate/polyethylene glycol-600 membranes, with varying ratios were prepared by 2-stage phase inversion protocol. The permeation properties were studied by subjecting membranes in indigenously fabricated reverse osmosis plant. After optimization of different CA/PEG ratios, the membrane with highest salt rejection capacity was selected and modified with varying amount of silica. The Modified membranes were characterized for their permeation properties, hydrophilicity, compositional analysis, thermal stability, mechanical strength and morphological studies. Silica significantly influenced the permeation performance of composite membrane. The flux enhanced from 0.35 to 2.46L/hm2 along with an 11.41% relative increase in salt rejection. The hydrophilicity was significantly enhanced by the addition of silica. In FTIR spectra, the broadening of the peak around 3500cm?1 and emergence of peak at 950cm?1 specified the incorporation of silica particles. The thermal analysis indicated the relative increase in degradation temperature (Tmax) and glass transition temperature (Tg) for CPS-5 membrane. The mechanical stability of the modified membranes, increased initially, but declined with further addition of silica. The results indicated that the incorporation of SiO2 content in the casting solution improved the fouling resistance of the membranes.

Adnan Ahmad; Sidra Waheed; Shahzad Maqsood Khan; Sabad e-Gul; Muhammad Shafiq; Muhammad Farooq; Khairuddin Sanaullah; Tahir Jamil

2015-01-01T23:59:59.000Z

226

Alkali-silica reaction products: Comparison between samples from concrete structures and laboratory test specimens  

SciTech Connect

Alkali-silica gels (ASG) were investigated in concrete from bridge structures (constructed from the 1920s to 2000), as well as in experimental specimens; employing optical microscopy, petrographic image analysis, and scanning electron microscopy combined with energy dispersive spectroscopy (SEM/EDS). The main differences were found in the chemical composition and morphology of the ASGs. ASGs which had formed in older concrete samples (50-80 years old) show a partly crystalline structure and higher Ca{sup 2+} content, indicating their aging and maturation. Younger concrete samples and experimental test specimens exhibit the presence of amorphous ASG. The chemistry of ASG from experimental specimens reflects the chemical composition of accelerating solutions. - Research Highlights: {yields} Quantitative analysis of alkali-silica gels {yields} Comparison of ASR in experimental conditions with ASR in bridge structures {yields} Investigation of factors affecting alkali-silica reaction {yields} Investigation of ASR of different types of aggregates.

Sachlova, Sarka, E-mail: lukschova@seznam.cz; Prikryl, Richard; Pertold, Zdenek

2010-12-15T23:59:59.000Z

227

CALE EOS form 2 fits for high pressure fused silica Hugoniot data  

SciTech Connect

The Hugoniot data on fused silica that are displayed on page 321 of the well-known volume ''LASL Shock Hugoniot Data, Stanley P. Marsh, Editor'' are fit to the EOS form 2 such as is used in CALE and other hydrocodes. Two fits are given: one to represent that data set over its full range (up to 84 GPa (840 kbar)) as well as a better fit for the pressure range below about 33 GPa (330 kbar). These EOSs have the strong point of being relatively simple for the user to implement and should be used to roughly represent the beyond-elastic response of fused silica in hydrocode simulations. They will not correctly reproduce the complex multiple-wave ramp-shock structure known to exist in fused silica at lower pressures.

Hare, D E; Managan, R A

2005-11-17T23:59:59.000Z

228

A New Class of Silica Crosslinked Micellar Core-Shell /nanoparticles."  

SciTech Connect

Micellar nanoparticles made of surfactants and polymers have attracted wide attention in the materials and biomedical community for controlled drug delivery, molecular imaging and sensing; however, their long-term stability remains a topic of intense study. Here we report a new class of robust, ultrafine (10nm) silica core-shell nanoparticles formed from silica crosslinked, individual block copolymer micelles. Compared with pure polymer micelles, the new core-shell nanoparticles have significantly improved stability and do not break down during dilution. They also achieve much higher loading capacity for a wide range of chemicals, with the entrapped molecules slowly released over a much longer period of time. A wide range of functional groups can be easily incorporated through co-condensation with the silica matrix. The potential to deliver hydrophobic agents into cancer cells has been demonstrated. Because of their unique properties, these novel core-shell nanoparticles could potentially provide a new nanomedicine platform for imaging, detection and treatment.

Huo, Qisheng; Liu, Jun; Wang, Li Q.; Jiang, Yingbing; Lambert, Timothy N.; Fang, Erica

2006-05-17T23:59:59.000Z

229

Preparation and sintering of silica-doped zirconia by colloidal processing  

SciTech Connect

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)

1997-09-01T23:59:59.000Z

230

SANS study of interaction of silica nanoparticles with BSA protein and their resultant structure  

SciTech Connect

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 (05 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: vkaswal@barc.gov.in; Aswal, V. K., E-mail: vkaswal@barc.gov.in [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)

2014-04-24T23:59:59.000Z

231

In situ atom transfer radical polymerization of styrene in the presence of nanoporous silica aerogel: Kinetic study and investigation of thermal properties  

Science Journals Connector (OSTI)

Atom transfer radical polymerization (ATRP) of styrene was performed at 110C in the presence of organically modified silica aerogel. A hydrophobic silica aerogel was prepared by a two-step, acidbase catalyz...

Seyed-Ataollah Mirshafiei-Langari; Vahid haddadi-Asl

2013-05-01T23:59:59.000Z

232

IMPROVING SILICA FUME FOR CONCRETE BY SURFACE TREATMENT X. Li and D.D.L. Chung1  

E-Print Network (OSTI)

(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.

233

The influence of polyethyleneimine type and molecular weight on the CO2 capture performance of PEI-nano silica adsorbents  

Science Journals Connector (OSTI)

Abstract Aminesilica adsorbents are considered alternatives to aqueous solutions of amines, which have been traditionally used to capture carbon dioxide (CO2) from flue gas. Among aminesilica adsorbents, polyethyleneimine (PEI)-silica is particularly effective at capturing CO2 from flue gas due to its high thermal stability. In this study, we investigated the influence of PEI type (i.e. branched vs. linear) and molecular weight on the CO2 capture performance of PEI-silica adsorbents. PEI molecular weight influenced the thermal stability of PEI-silica adsorbents; however, when the molecular weight was ?1200Da the increase in stability was negligible in the temperature range of 25160C. Branched \\{PEIs\\} (BPEIs) achieved higher CO2 saturated sorption capacities compared to linear \\{PEIs\\} (LPEIs); however, \\{LPEIs\\} were more stable than \\{BPEIs\\} during CO2 sorptiondesorption cycling. PEI molecular weight also influenced the CO2 saturated sorption capacity; CO2 saturated sorption capacity decreased as PEI molecular weight increased, and among the adsorbents tested in this study BPEI/800-silica had the highest CO2 saturated sorption capacity (202mg CO2/g adsorbent). Both PEI type and molecular weight exhibited influence on the sorption or desorption heat of PEI-silica adsorbents. The CO2 regeneration heat was much lower than that of MEA solution for all PEI-silica adsorbents tested in this study.

Kaimin Li; Jianguo Jiang; Feng Yan; Sicong Tian; Xuejing Chen

2014-01-01T23:59:59.000Z

234

Am J Epidemiol . Author manuscript Aluminum and silica in drinking water and the risk of Alzheimers disease'  

E-Print Network (OSTI)

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

Paris-Sud XI, Université de

235

An experimental investigation into the effects of fluid composition on certain geothermometry methods  

E-Print Network (OSTI)

at the lower temperatures, and 5) thermal waters do not mix with shallower, cooler ground water. Silica geothermometer The dissolved silica content of geothermal water is used in geothermometry because silica is present in most geologic settings... This presents a real problem in evaluation of the geo- thermal potential of the area; one method gives reservoir temperatures high enough for potential geothermal energy use but another gives temperatures that are too low. The waters studied by Henry can...

Pope, Leslie Anne

2012-06-07T23:59:59.000Z

236

Decomposition of cumyl hydroperoxide in the presence of sulphonated silica in a flow-type system  

SciTech Connect

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.

1993-12-31T23:59:59.000Z

237

Applications of Geothermally-Produced Colloidal Silica in Reservoir Management - Smart Gels  

SciTech Connect

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

2013-01-31T23:59:59.000Z

238

The exchange rate for tritiated water vapor adsorbed on silica gel  

E-Print Network (OSTI)

THE EXCHANGE RATE FOR TRITIATED WATER VAPOR ADSORBED ON SILICA GEL A Thesis by PENNY ALANE SHAMBLIN Submitted to the Cnaduate College of Texas A8cM University in partial fulfihmnt of the requirements for the degree of MASTER OF SCIENCE... December 1987 Major Subject: Health Physics THE EXCHANGE RATE FOR ~TED WATER VAPOR ADSORBED ON SILICA GEL A Thesis by PENNY ALANE SHAMBUN Approved as to style and content by: Milton E. McLain (Chair of Committee) Gerald A. Schla (Member) Ric ard...

Shamblin, Penny Alane

2012-06-07T23:59:59.000Z

239

Applications of Geothermally-Produced Colloidal Silica in Reservoir Management - Smart Gels  

DOE Data Explorer (OSTI)

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

240

Method and composition in which metal hydride particles are embedded in a silica network  

DOE Patents (OSTI)

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)

1999-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "multicomponent geothermometers silica" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Monodisperse metal nanoparticle catalysts on silica mesoporous supports: synthesis, characterizations, and catalytic reactions  

SciTech Connect

The design of high performance catalyst achieving near 100% product selectivity at maximum activity is one of the most important goals in the modern catalytic science research. To this end, the preparation of model catalysts whose catalytic performances can be predicted in a systematic and rational manner is of significant importance, which thereby allows understanding of the molecular ingredients affecting the catalytic performances. We have designed novel 3-dimensional (3D) high surface area model catalysts by the integration of colloidal metal nanoparticles and mesoporous silica supports. Monodisperse colloidal metal NPs with controllable size and shape were synthesized using dendrimers, polymers, or surfactants as the surface stabilizers. The size of Pt, and Rh nanoparticles can be varied from sub 1 nm to 15 nm, while the shape of Pt can be controlled to cube, cuboctahedron, and octahedron. The 3D model catalysts were generated by the incorporation of metal nanoparticles into the pores of mesoporous silica supports via two methods: capillary inclusion (CI) and nanoparticle encapsulation (NE). The former method relies on the sonication-induced inclusion of metal nanoparticles into the pores of mesoporous silica, whereas the latter is performed by the encapsulation of metal nanoparticles during the hydrothermal synthesis of mesoporous silica. The 3D model catalysts were comprehensively characterized by a variety of physical and chemical methods. These catalysts were found to show structure sensitivity in hydrocarbon conversion reactions. The Pt NPs supported on mesoporous SBA-15 silica (Pt/SBA-15) displayed significant particle size sensitivity in ethane hydrogenolysis over the size range of 1-7 nm. The Pt/SBA-15 catalysts also exhibited particle size dependent product selectivity in cyclohexene hydrogenation, crotonaldehyde hydrogenation, and pyrrole hydrogenation. The Rh loaded SBA-15 silica catalyst showed structure sensitivity in CO oxidation reaction. In addition, Pt-mesoporous silica core-shell structured NPs (Pt{at}mSiO{sub 2}) were prepared, where the individual Pt NP is encapsulated by the mesoporous silica layer. The Pt{at}mSiO{sub 2} catalysts showed promising catalytic activity in high temperature CO oxidation. The design of catalytic structures with tunable parameters by rational synthetic methods presents a major advance in the field of catalyst synthesis, which would lead to uncover the structure-function relationships in heterogeneous catalytic reactions.

Somorjai, G.A.

2009-09-14T23:59:59.000Z

242

Silica Scale Management: Lowering Operating Costs through Improved Scale Control, and Adding Value by Extracting Marketable By-Products  

SciTech Connect

We are using laboratory and field experiments to design modeling tools and technology that will improve silica scale management practices in geothermal plants. Our work will help to lower operating costs through improved scale prediction and add new revenue streams from sale of mineral byproducts extracted from geothermal fluids. Improving the economics and effectiveness of scale control programs and/or extraction systems in geothermal operations requires a coupled kinetic-thermodynamic model of silica behavior. Silica scale precipitation is a multi-step process, involving a nucleation-related induction period, aqueous polymerization, condensation of polymers to form colloids, and deposition onto a solid surface. Many chemical and physical variables influence the rates of these steps and their impacts must be quantified and predictable in order to optimally control silica behavior. To date, in laboratory studies, we have quantified the effects on silica polymerization of the following set of chemical variables: Na at 500 and 2000 ppm, pH values from 5 to 9, temperatures of 25 and 50 C, and silica saturation values from 1.2 to 6 at initial dissolved silica concentrations of 600 ppm. Lowering pH both increases the induction time prior to polymerization and decreases the polymerization rate. We have successfully used a multiple regression model to predict polymerization rates from these variables. Geothermal fluids contain significant dissolved concentrations of potentially valuable mineral resources such as zinc, lithium, cesium and rubidium, but silica fouling interferes with traditional extraction methods. We are developing customized and new technologies to extract the silica as a commercial-grade commodity as well as the valuable metals. We are conducting field testing of some of these techniques at a Mammoth, CA geothermal plant using a reverse osmosis unit to concentrate the fluid, adding a commercial agglomerating agent to promote silica precipitation, and then removing the silica using a tangential flow ultrafilter. The particle size, surface area and trace impurities of the silica are characterized for comparison with commercial-grade silica products. We are also testing ion exchange resins and other functionalized materials to extract potentially economic concentrations of lithium, cesium, and rubidium that are enriched in the reverse osmosis concentrate.

Burton, E A; Bourcier, W L; Wallce, A; Bruton, C J; Leif, R

2003-06-18T23:59:59.000Z

243

Enhancement in hydrophobicity of silica films using metal acetylacetonate and heat treatment  

Science Journals Connector (OSTI)

Water is one of the most affecting chemicals that can cause damage to the solid surface. To protect the surface due to the action of water, the surface should be made hydrophobic. In the present study, the improvement in hydrophobicity of silica films using metal acetylacetonate (M-acac) by employing heat treatment to methyltrimethoxy silane (MTMS) based silica coatings is reported as a novel attempt. Instead of following the established trends of the surface derivatization or co-precursor method, iron acetylacetonate Fe(acac)3, copper acetylacetonate Cu(acac)2 and heat treatment were used to incorporate hydrophobicity with silica coatings. As M-acac is readily soluble in organic solvents, Fe(acac)3 and Cu(acac)2 were dissolved in methanol (MeOH) and their concentration was varied from 0 to 0.025M. The coating solution was prepared by optimizing molar ratio of MTMS:MeOH:basic H2O to 1:7.15:6.34, respectively. Gelation time (tg) for Cu(acac)2 containing silica sol and that containing Fe(acac)3 were noted to be 30 and 55min, respectively. The substrates were taken out after gelation and heat treated at 150C for 2h. The heat treated films showed a dramatic increase in the static water contact angle from 82 to as high as 142.

Sunetra L. Dhere; Uzma K.H. Bangi; Sanjay S. Latthe; A. Venkateswara Rao

2011-01-01T23:59:59.000Z

244

Density hysteresis of heavy water confined in a nanoporous silica matrix  

E-Print Network (OSTI)

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 ...

Zhang, Yang

245

Helium irradiation effects in polycrystalline Si, silica, and single crystal Si  

SciTech Connect

Transmission electron microscopy (TEM) has been used to investigate the effects of room temperature 6 keV helium ion irradiation of a thin ({approx_equal}55 nm thick) tri-layer consisting of polycrystalline Si, silica, and single-crystal Si. The ion irradiation was carried out in situ within the TEM under conditions where approximately 24% of the incident ions came to rest in the specimen. This paper reports on the comparative development of irradiation-induced defects (primarily helium bubbles) in the polycrystalline Si and single-crystal Si under ion irradiation and provides direct measurement of a radiation-induced increase in the width of the polycrystalline layer and shrinkage of the silica layer. Analysis using TEM and electron energy-loss spectroscopy has led to the hypothesis that these result from helium-bubble-induced swelling of the silicon and radiation-induced viscoelastic flow processes in the silica under the influence of stresses applied by the swollen Si layers. The silicon and silica layers are sputtered as a result of the helium ion irradiation; however, this is estimated to be a relatively minor effect with swelling and stress-related viscoelastic flow being the dominant mechanisms of dimensional change.

Abrams, K. J.; Greaves, G.; Berg, J. A. van den [Materials and Physics Research Centre, University of Salford, Salford (United Kingdom); Hinks, J. A.; Donnelly, S. E. [School of Computing and Engineering, University of Huddersfield, Huddersfield (United Kingdom); Pawley, C. J. [Materials and Physics Research Centre, University of Salford, Salford (United Kingdom); School of Computing and Engineering, University of Huddersfield, Huddersfield (United Kingdom); Eyidi, D. [Institut Pprime, Universite de Poitiers, Poitiers (France); Ward, M. B. [Institute for Materials Research, University of Leeds, Leeds (United Kingdom)

2012-04-15T23:59:59.000Z

246

EFFECTS OF SAND AND SILICA FUME ON THE VIBRATION DAMPING BEHAVIOR OF CEMENT  

E-Print Network (OSTI)

. 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

Chung, Deborah D.L.

247

Acid strength of silica-supported oxide catalysts studied by microcalorimetric measurements of pyridine adsorption  

SciTech Connect

Microcalorimetric measurements of the differential heat of pyridine adsorption were used to probe the distribution of acid strength on a series of silica-supported oxide catalysts. Depositing oxides of the following cations onto silica increased the acid strength of the catalyst: Ga{sup 3{plus}}, Zn{sup 2{plus}}, Al{sup 3{plus}}, Fe{sup 3{plus}}, Fe{sup 2{plus}}, Mg{sup 2{plus}}, and Sc{sup 3{plus}}. The acid strength distribution curves for the supported oxide samples showed either two or three regions of constant heat of adsorption while silica had an energetically homogeneous surface. The Ga, Al, and Sc samples were found to have both Bronsted and Lewis acidity while the remaining samples showed only Lewis acidity. Incremental adsorption of pyridine indicated that the initial region of highest heat corresponds to strong Lewis acidity while intermediate heats seemed to be due to weaker Lewis acid sites or a combination of Lewis and Bronsted acid sites. The final region of lowest heat was due to H-bonded pyridine on silica. Estimates of the entropies of adsorption were determined, providing information about the mobility of the adsorbed pyridine molecules. The initial differential heat of adsorption increases proportionally to the Sanderson electronegativity of the added oxide.

Cardona-Martinez, N.; Dumesic, J.A. (Univ. of Wisconsin, Madison (USA))

1991-02-01T23:59:59.000Z

248

The fatigue of high-strength fused silica optical fibers in low humidity q  

E-Print Network (OSTI)

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

Matthewson, M. John

249

Activation energy and entropy of dynamic fatigue of pristine silica optical fibers  

E-Print Network (OSTI)

, 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

Matthewson, M. John

250

CHEMICAL KINETICS MODELS FOR THE FATIGUE BEHAVIOR OF FUSED SILICA OPTICAL FIBER  

E-Print Network (OSTI)

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

Matthewson, M. John

251

Silica entrapment for significantly stabilized, energy-conducting light-harvesting complex (LHCII)  

Science Journals Connector (OSTI)

Silica entrapment for significantly stabilized, energy-conducting light-harvesting complex (LHCII) ... The entrapped LHCII stayed functional at 50 C for up to 24 h instead of a few minutes in detergent solution and clearly showed energy transfer between complexes. ...

Sebastian Rder; Stephan Hobe; Harald Paulsen

2014-11-03T23:59:59.000Z

252

Spectroscopic Studies of Atmospheric Relevant Air-Aqueous and Air-Silica DISSERTATION  

E-Print Network (OSTI)

process in the atmosphere. As models of these phenomena, interfacial water vapor uptake by #12;iii to the air-water interface were examined. Sum frequency generation (SFG), a surface specific techniqueSpectroscopic Studies of Atmospheric Relevant Air-Aqueous and Air-Silica Interfaces DISSERTATION

253

Additive-Driven Dissolution Enhancement of Colloidal Silica. 3. Fluorine-Containing Additives  

Science Journals Connector (OSTI)

Add to ACS ChemWorx ... Among the former are silica removal by ion-exchange methods(13) and utilization of scale inhibitors. ... Therefore, we would like to broaden the scope of the potential utilization of fluorine-containing additives with the objective that a broader choice of additive selection will be available to end-users. ...

Konstantinos D. Demadis; Maria Somara; Eleftheria Mavredaki

2012-01-20T23:59:59.000Z

254

Silicatitania aerogel monoliths with large pore volume and surface area by ambient pressure drying  

Science Journals Connector (OSTI)

Ambient pressure drying has been carried out for the synthesis of silicatitania aerogel monoliths. The prepared aerogels show densities in the range 0.340.38g/cm3. The surface area and pore volume of these mix...

P. R. Aravind; P. Shajesh; P. Mukundan

2009-12-01T23:59:59.000Z

255

Production of silica aerogel microparticles loaded with ammonia borane by batch and semicontinuous supercritical drying techniques  

Science Journals Connector (OSTI)

Abstract Silica aerogel microparticles were prepared by supercritical drying and used as support for hydrogen-storing ammonia borane (AB). The formation of aerogel microparticles was done using two different processes: batch supercritical fluid extraction and a semicontinuous drying process. Silica aerogel microparticles with a surface area ranging from 400 to 800m2/g, a volume of pores of 1cm3/g, and a mean particle diameter ranging from 12 to 27?m were produced using the two drying techniques. The particle size distribution (PSD) of the microparticles was influenced by shear rate, amount of catalyst, hydrophilichydrophobic solvent ratio and hydrophobic surface modification. In particular, irregular aerogel particles were obtained from hydrophilic gels, while regular, spherical particles with smooth surfaces were obtained from hydrophobic gels. AB was loaded into silica aerogel microparticles in concentrations ranging from 1% till 5% wt. Hydrogen release kinetics from the hydride-loaded aerogel was analyzed with a volumetric cell at 80C. By stabilization of AB into the silica aerogel microparticles, an improvement of the release rate of hydrogen from AB was observed.

Miriam Rueda; Luis Miguel Sanz-Moral; Antonio Nieto-Mrquez; Pablo Longone; Facundo Mattea; ngel Martn

2014-01-01T23:59:59.000Z

256

Application of stochastic weighted algorithms to a multidimensional silica particle model  

SciTech Connect

Highlights: Stochastic weighted algorithms (SWAs) are developed for a detailed silica model. An implementation of SWAs with the transition kernel is presented. The SWAs solutions converge to the direct simulation algorithms (DSA) solution. The efficiency of SWAs is evaluated for this multidimensional particle model. It is shown that SWAs can be used for coagulation problems in industrial systems. -- Abstract: This paper presents a detailed study of the numerical behaviour of stochastic weighted algorithms (SWAs) using the transition regime coagulation kernel and a multidimensional silica particle model. The implementation in the SWAs of the transition regime coagulation kernel and associated majorant rates is described. The silica particle model of Shekar et al. [S. Shekar, A.J. Smith, W.J. Menz, M. Sander, M. Kraft, A multidimensional population balance model to describe the aerosol synthesis of silica nanoparticles, Journal of Aerosol Science 44 (2012) 8398] was used in conjunction with this coagulation kernel to study the convergence properties of SWAs with a multidimensional particle model. High precision solutions were calculated with two SWAs and also with the established direct simulation algorithm. These solutions, which were generated using large number of computational particles, showed close agreement. It was thus demonstrated that SWAs can be successfully used with complex coagulation kernels and high dimensional particle models to simulate real-world systems.

Menz, William J. [Department of Chemical Engineering and Biotechnology, University of Cambridge, New Museums Site, Pembroke Street, Cambridge CB2 3RA (United Kingdom)] [Department of Chemical Engineering and Biotechnology, University of Cambridge, New Museums Site, Pembroke Street, Cambridge CB2 3RA (United Kingdom); Patterson, Robert I.A.; Wagner, Wolfgang [Weierstrass Institute for Applied Analysis and Stochastics, Mohrenstrasse 39, Berlin 10117 (Germany)] [Weierstrass Institute for Applied Analysis and Stochastics, Mohrenstrasse 39, Berlin 10117 (Germany); Kraft, Markus, E-mail: mk306@cam.ac.uk [Department of Chemical Engineering and Biotechnology, University of Cambridge, New Museums Site, Pembroke Street, Cambridge CB2 3RA (United Kingdom)] [Department of Chemical Engineering and Biotechnology, University of Cambridge, New Museums Site, Pembroke Street, Cambridge CB2 3RA (United Kingdom)

2013-09-01T23:59:59.000Z

257

Enhanced green upconversion luminescence in YbTb co-doped sintered silica nanoporous glass  

Science Journals Connector (OSTI)

We report on a new kind of green-emitting (543nm) high-silica luminous...3+Tb3+...co-doped nanoporous glass. The fluorescence spectra show that there is an energy transfer between Yb3+ and Tb3+. The energy tran...

Yingbo Chu; Yu Yang; Zijun Liu; Lei Liao; Yibo Wang; Jiaming Li

2014-11-01T23:59:59.000Z

258

Silica Supported Single-Walled Carbon Nanotubes as a Modifier in Polyethylene Composites  

E-Print Network (OSTI)

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

259

Heavy metal phosphate nanophases in silica: influence of radiolysis probed via f-electron state properties  

SciTech Connect

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: beitz@anl.gov; 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)

2005-02-15T23:59:59.000Z

260

Fluorescent silica colloids for study and visualization of skin care products  

E-Print Network (OSTI)

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

Note: This page contains sample records for the topic "multicomponent geothermometers silica" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Effects of Surface Modification Conditions on Hydrophobicity of Silica-based Coating Additives  

SciTech Connect

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

2013-01-01T23:59:59.000Z

262

Oxygen isotope fractionation between amorphous silica and water at 3493C  

Science Journals Connector (OSTI)

... , P-3 and P-4) along the reinjection lines in the Otake and Hatchobaru geothermal power plants. Although it would have been preferable to obtain the amorphous silica at ... temperatures, these four points were the only ones available for this experiment. The same geothermal water from the Otake station flows at P-l and P-4; at P- ...

Itsuro Kita; Sachihiro Taguchi; Osamu Matsubaya

1985-03-07T23:59:59.000Z

263

Sodium-Silicate Route to Submicrometer Hybrid PEG@Silica Particles  

Science Journals Connector (OSTI)

Sodium-Silicate Route to Submicrometer Hybrid PEG@Silica Particles ... Supported by the Nano Functional Materials (NFM) MAGNET Program of the Israel Ministry of Trade and Industry, by the Infrastructure (Tashtiot) Program of the Israel Ministry of Science, and by the European Functionalized Advanced Materials and Engineering Hybrids and Ceramic (FAME) Network of Excellence (NOE). ...

Hila Elimelech; David Avnir

2008-03-04T23:59:59.000Z

264

Flame-Retardant Epoxy Resin Nanocomposites Reinforced with Polyaniline-Stabilized Silica Nanoparticles  

E-Print Network (OSTI)

, Henry A. Colorado, Suying Wei,*,# and Zhanhu Guo*, Integrated Composites Lab (ICL), Dan F. Smith silsesquioxanes (POSS) reinforced epoxy composites.10 For the third method, the inorganic nanoparticles are often (ATH),13 silica (SiO2),14 nanoclay,15 and newly developed phosphorus- containing flame retardants 9

Guo, John Zhanhu

265

Mechanical behavior of silica optical fibers coated with low index, low surface energy perfluorinated polymer  

E-Print Network (OSTI)

based on perfluorinated polymer were prepared for use as UV-curable optical cladding for silica fibers fibers, with a core doped with rare earth elements, could potentially be used as laser fibers but require special optical cladding. This cladding should have a low refractive index, low modulus of elasticity

Matthewson, M. John

266

Thulium-doped silica fibers with enhanced 3 H4 level lifetime  

E-Print Network (OSTI)

of cheap mass production. With the cladding-pump technique, fiber lasers and amplifiers have proven-power, high-brightness laser beams. The most important multi-watt fiber lasers were reported using double-clad at 810 nm can be achieved for specific ranges of the laser cavity parameters in silica-based thulium

Paris-Sud XI, Université de

267

Acidity and catalytic activity of zeolite catalysts bound with silica and alumina  

E-Print Network (OSTI)

. 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

2004-09-30T23:59:59.000Z

268

Alkanethiol-Induced Structural Rearrangements in Silica-Gold Core-Shell-type Nanoparticle Clusters: An  

E-Print Network (OSTI)

Alkanethiol-Induced Structural Rearrangements in Silica-Gold Core-Shell-type Nanoparticle Clusters 21, 2003. In Final Form: April 19, 2004 Electrostatically bonded SiO2,Au nanoparticle clusters form by reaction of 3-aminopropylsilane-modified SiO2 spheres (470 nm) with citrate-coated gold nanoparticles (9

Guo, Ting

269

MODELING THE MEAN INTERACTION FORCES BETWEEN POWDER APPLICATION TO SILICA GEL-MAGNESIUM STEARATE MIXTURES.  

E-Print Network (OSTI)

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

Paris-Sud XI, Université de

270

Monolithic Composites of Silica Aerogels by Reactive Supercritical Deposition of Hydroxy-Terminated Poly(Dimethylsiloxane)  

Science Journals Connector (OSTI)

The method involves dissolution of PDMS(OH) in supercritical CO2 (scCO2) and then exposure of the aerogel samples to this single phase mixture of PDMS(OH)-CO2. ... Upon supercritical deposition, the polymer molecules were discovered to react with the hydroxyl groups on the silica aerogel surface and form a conformal coating on the surface. ...

D. Sanli; C. Erkey

2013-10-29T23:59:59.000Z

271

9422 Stratospheric ice catalyzes chlorine reactions 9428 Fusing silk and silica  

E-Print Network (OSTI)

, at temperatures this high, cirrus cloud formation could also be affected. -- P.D. ``Hydrogen chloride may lead to unique methods of prepar- ing spider silk and producing silica particles with precise in aqueous solutions. Wong Po Foo et al. say their technique may allow the production of other resilient

McFadden, Geoff

272

EPR study of the adsorption of dioxin vapours onto microporous carbons and mesoporous silica  

E-Print Network (OSTI)

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.

273

Anhydrous Phosphoric Acid Functionalized Sintered Mesoporous Silica Nanocomposite Proton Exchange Membranes for Fuel Cells  

Science Journals Connector (OSTI)

Anhydrous Phosphoric Acid Functionalized Sintered Mesoporous Silica Nanocomposite Proton Exchange Membranes for Fuel Cells ... The cell performance and stability may be further improved through an optimization of the interfacial contact between the electrocatalytic layer and the inorganic membrane. ... polycondensation procedure was optimized for individual case of PBI synthesis in order to obtain inherent viscosity of ?1 dL/g. ...

Jie Zeng; Beibei He; Krystina Lamb; Roland De Marco; Pei Kang Shen; San Ping Jiang

2013-10-14T23:59:59.000Z

274

First-principles calculations of defects in oxygen-deficient silica exposed to hydrogen  

Science Journals Connector (OSTI)

Hydrogen-related defects and oxygen vacancies in silica are analyzed using first-principles density-functional calculations. Energetics, structures, charge-state levels, and hyperfine parameters are determined. These calculations identify the hydrogen bridge related to the E4? center as the defect responsible for the stress-induced leakage current, a forerunner of dielectric breakdown of gate oxides in transistors.

Peter E. Blchl

2000-09-01T23:59:59.000Z

275

Study of pure-silica Zeolite Nucleation and Growth from Solution  

E-Print Network (OSTI)

of silica precursor particles with size of 2-5 nm in these mixtures prior to and during hydrothermal treatments have been observed through dynamic light scattering (DLS), small-angle X-ray (SAXS) and transmission electron microscopy (TEM). However...

Li, Xiang

2011-10-21T23:59:59.000Z

276

Apparent activation energy of fused silica optical fibers in static fatigue in aqueous environments  

E-Print Network (OSTI)

to occur when ambient moisture reacts with the fiber surface causing subcritical crack growth.1?3 Fatigue of silica optical fiber is therefore controlled by the crack growth rate, c : , which depends for the crack growth, which was originally proposed by Charles and Hillig, based on simple chemical kinetics

Matthewson, M. John

277

Acoustic and Thermal Characterization of Oil Migration, Gas Hydrates Formation and Silica Diagenesis  

E-Print Network (OSTI)

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

278

Determination of silica scale deposition rates and thresholds applied toward protection of injection reservoirs. Quarterly progress report, July 1--September 30, 1998  

SciTech Connect

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.

NONE

1998-11-01T23:59:59.000Z

279

Streamlined life cycle assessment of transparent silica aerogel made by supercritical drying  

Science Journals Connector (OSTI)

When developing sustainable building fabric technologies, it is essential that the energy use and CO2 burden arising from manufacture does not outweigh the respective in-use savings. This study investigates this paradigm by carrying out a streamlined life cycle assessment (LCA) of silica aerogel. This unique, nanoporous translucent insulation material has the lowest thermal conductivity of any solid, retaining up to four times as much heat as conventional insulation, whilst being highly transparent to light and solar radiation. Monolithic silica aerogel has been cited as the holy grail of future glazing technology. Alternatively, translucent granular aerogel is now being produced on a commercial scale. In each case, many solvents are used in production, often accompanied by intensive drying processes, which may consume large amounts of energy and CO2. To date, there has been no peer-reviewed LCA of this material conducted to the ISO 14000 standard. Primary data for this cradle-to-factory gate LCA is collected for silica aerogel made by low and high temperature supercritical drying. In both cases, the mass of raw materials and electricity usage for each process is monitored to determine the total energy use and CO2 burden. Findings are compared against the predicted operational savings arising from retrofitting translucent silica aerogel to a single glazed window to upgrade its thermal performance. Results should be treated as a conservative estimate as the aerogel is produced in a laboratory, which has not been developed for mass manufacture or refined to reduce its environmental impact. Furthermore, the samples are small and assumptions to upscale the manufacturing volume occur without major changes to production steps or equipment used. Despite this, parity between the CO2 burden and CO2 savings is achieved in less than 2years, indicating that silica aerogel can provide a measurable environmental benefit.

Mark Dowson; Michael Grogan; Tim Birks; David Harrison; Salmaan Craig

2012-01-01T23:59:59.000Z

280

The subsurface temperature assessment by means of an indirect electromagnetic geothermometer  

Science Journals Connector (OSTI)

...new challenges for geothermal energy, Volterra, Italy, Extended...New challenges for geothermal energy, Volterra, Italy, Extended...2001, Three-dimensional geothermic model of the Karskii shelf...exploitation of geothermal energy resources in South America...

Viacheslav Spichak; Olga Zakharova

Note: This page contains sample records for the topic "multicomponent geothermometers silica" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

New Improved Equations For Na-K, Na-Li And Sio2 Geothermometers...  

Open Energy Info (EERE)

errors (2-3%) than for the original equation (5-29%). Authors Surendra P. Verma and Edgar Santoyo Published Journal Journal of Volcanology and Geothermal Research, 1997 DOI Not...

282

Nonaqueous Phase Liquid Dissolution in Porous Media: Multi-Scale Effects of Multi-Component Dissolution Kinetics on Cleanup Time  

SciTech Connect

Industrial organic solvents such as trichloroethylene (TCE) and tetrachloroethylene (PCE) constitute a principal class of groundwater contaminants. Cleanup of groundwater plume source areas associated with these compounds is problematic, in part, because the compounds often exist in the subsurface as dense nonaqueous phase liquids (DNAPLs). Ganglia (or 'blobs') of DNAPL serve as persistent sources of contaminants that are difficult to locate and remediate (e.g. Fenwick and Blunt, 1998). Current understanding of the physical and chemical processes associated with dissolution of DNAPLs in the subsurface is incomplete and yet is critical for evaluating long-term behavior of contaminant migration, groundwater cleanup, and the efficacy of source area cleanup technologies. As such, a goal of this project has been to contribute to this critical understanding by investigating the multi-phase, multi-component physics of DNAPL dissolution using state-of-the-art experimental and computational techniques. Through this research, we have explored efficient and accurate conceptual and numerical models for source area contaminant transport that can be used to better inform the modeling of source area contaminants, including those at the LLNL Superfund sites, to re-evaluate existing remediation technologies, and to inspire or develop new remediation strategies. The problem of DNAPL dissolution in natural porous media must be viewed in the context of several scales (Khachikian and Harmon, 2000), including the microscopic level at which capillary forces, viscous forces, and gravity/buoyancy forces are manifested at the scale of individual pores (Wilson and Conrad, 1984; Chatzis et al., 1988), the mesoscale where dissolution rates are strongly influenced by the local hydrodynamics, and the field-scale. Historically, the physico-chemical processes associated with DNAPL dissolution have been addressed through the use of lumped mass transfer coefficients which attempt to quantify the dissolution rate in response to local dissolved-phase concentrations distributed across the source area using a volume-averaging approach (Figure 1). The fundamental problem with the lumped mass transfer parameter is that its value is typically derived empirically through column-scale experiments that combine the effects of pore-scale flow, diffusion, and pore-scale geometry in a manner that does not provide a robust theoretical basis for upscaling. In our view, upscaling processes from the pore-scale to the field-scale requires new computational approaches (Held and Celia, 2001) that are directly linked to experimental studies of dissolution at the pore scale. As such, our investigation has been multi-pronged, combining theory, experiments, numerical modeling, new data analysis approaches, and a synthesis of previous studies (e.g. Glass et al, 2001; Keller et al., 2002) aimed at quantifying how the mechanisms controlling dissolution at the pore-scale control the long-term dissolution of source areas at larger scales.

McNab, W; Ezzedine, S; Detwiler, R

2007-02-26T23:59:59.000Z

283

Development of multicomponent hybrid density functional theory with polarizable continuum model for the analysis of nuclear quantum effect and solvent effect on NMR chemical shift  

SciTech Connect

We have developed the multicomponent hybrid density functional theory [MC-(HF+DFT)] method with polarizable continuum model (PCM) for the analysis of molecular properties including both nuclear quantum effect and solvent effect. The chemical shifts and H/D isotope shifts of the picolinic acid N-oxide (PANO) molecule in chloroform and acetonitrile solvents are applied by B3LYP electron exchange-correlation functional for our MC-(HF+DFT) method with PCM (MC-B3LYP/PCM). Our MC-B3LYP/PCM results for PANO are in reasonable agreement with the corresponding experimental chemical shifts and isotope shifts. We further investigated the applicability of our method for acetylacetone in several solvents.

Kanematsu, Yusuke; Tachikawa, Masanori [Quantum Chemistry Division, Yokohama City University, Seto 22-2, Kanazawa-ku, Yokohama 236-0027 (Japan)] [Quantum Chemistry Division, Yokohama City University, Seto 22-2, Kanazawa-ku, Yokohama 236-0027 (Japan)

2014-04-28T23:59:59.000Z

284

A near-infrared census of the multi-component stellar structure of early-type dwarf galaxies in the Virgo cluster  

E-Print Network (OSTI)

The fraction of star-forming to quiescent dwarf galaxies varies from almost infinity in the field to zero in the centers of rich galaxy clusters. What is causing this pronounced morphology-density relation? What do quiescent dwarf galaxies look like when studied in detail, and what conclusions can be drawn about their formation mechanism? Here we study a nearly magnitude-complete sample (-19 deep near-infrared images from the SMAKCED project. We fit two-dimensional models with optional inner and outer components, as well as bar and lens components (in ~15% of the galaxies), to the galaxy images. While a single S\\'ersic function may approximate the overall galaxy structure, it does not entirely capture the light distribution of two-thirds of our galaxies, for which multi-component models provide a better fit. This fraction of complex galaxies shows a strong dependence on luminosity, being larger for brighter objects. We analyze the global and compone...

Janz, J; Lisker, T; Salo, H; Peletier, R F; Niemi, S -M; Toloba, E; Hensler, G; Falcn-Barroso, J; Boselli, A; Brok, M den; Hansson, K S A; Meyer, H T; Ry?, A; Paudel, S

2013-01-01T23:59:59.000Z

285

Biological Applications and Transmission Electron Microscopy Investigations of Mesoporous Silica Nanoparticles  

SciTech Connect

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

2006-05-01T23:59:59.000Z

286

Natural hydrous amorphous silica: Quantitation of network speciation and hydroxyl content by 29Si MAS NMR and vibrational spectroscopy  

Science Journals Connector (OSTI)

...technological and industrial applications (e.g., desiccants, aerogels, SiO2 films in semiconductors). In natural settings, amorphous...1990) NMR determination of the fractal dimension in silica aerogels. Physical Review Letters, 65, 614-617. Engelhardt, G...

Steven M. Chemtob; George R. Rossman; Jonathan F. Stebbins

287

Fast-neutron radiation effects in a silica-core optical fiber studied by a CCD-camera spectrometer  

Science Journals Connector (OSTI)

A simple CCD-camera spectrometer was deployed at the Los Alamos Spallation Radiation Effects Facility to characterize fast-neutron irradiation effects in several silica-based optical...

Griscom, D L; Gingerich, M E; Friebele, E J; Putnam, M; Unruh, W

1994-01-01T23:59:59.000Z

288

Near-surface modification of optical properties of fused silica by low-temperature hydrogenous atmospheric pressure plasma  

Science Journals Connector (OSTI)

In this Letter, we report on the near-surface modification of fused silica by applying a hydrogenous atmospheric pressure plasma jet at ambient temperature. A significant decrease in...

Gerhard, Christoph; Tasche, Daniel; Brckner, Stephan; Wieneke, Stephan; Vil, Wolfgang

2012-01-01T23:59:59.000Z

289

DOI: 10.1002/chem.201203003 A Top-Down Synthesis Route to Ultrasmall Multifunctional Gd-Based Silica  

E-Print Network (OSTI)

-Based Silica Nanoparticles for Theranostic Applications Anna Mignot,[a, b, e] Charles Truillet,[a] Fran?ois Lux or sensitising for radiotherapy.[1­5] Nanoparticles for theranostic applications need to be bio- compatible

290

Binding Specificity of Amino Acids to Amorphous Silica Surfaces: Solid-State NMR of Glycine on SBA-15  

Science Journals Connector (OSTI)

Herein, [1-13C,15N]glycine interactions with amorphous silica surface of SBA-15 were comprehensively characterized using multinuclear, solid-state NMR techniques (REDOR, TEDOR, SLF, 2D-HETCOR). ...

Ira Ben Shir; Shifi Kababya; Asher Schmidt

2012-04-12T23:59:59.000Z

291

Evaluation of Laser-Induced Breakdown Spectroscopy (LIBS) for Measurement of Silica on Filter Samples of Coal Dust  

Science Journals Connector (OSTI)

Airborne silica dust (quartz) is common in coal mines and represents a respiratory hazard that can lead to silicosis, a potentially fatal lung disease. With an eye toward developing a...

Stipe, Christopher B; Miller, Arthur L; Brown, Jonathan; Guevara, Edward; Cauda, Emanuele

2012-01-01T23:59:59.000Z

292

Mechanical relaxation behavior of polyurethanes reinforced with the in situ-generated sodium silica-polyphosphate nanophase  

E-Print Network (OSTI)

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

2014-10-31T23:59:59.000Z

293

Fabrication of ultrafine carbon fibers possessing a nanoporous structure from electrospun polyvinyl alcohol fibers containing silica nanoparticles  

Science Journals Connector (OSTI)

Ultrafine carbon fibers with a nanoporous structure were fabricated by the template method using silica nanoparticles (NPs) embedded in fibers of approximate diameter 500 nm, electrospun from an aqueous solution of polyvinyl alcohol, CoCl2, ...

Koichi Sawada, Shinji Sakai, Masahito Taya

2014-01-01T23:59:59.000Z

294

The role of effective stress on silica solubility and pressure solution: an experimental investigation in a flow-through system  

E-Print Network (OSTI)

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

2012-06-07T23:59:59.000Z

295

Infrared spectroscopic study of the adsorption of carbon monoxide on silica-supported copper oxide  

SciTech Connect

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.

1980-10-01T23:59:59.000Z

296

Lasing characteristics of Er/sup 3 +/-doped silica fibers from 1553 up to 1603 nm  

SciTech Connect

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.

1988-07-15T23:59:59.000Z

297

Experimental stressstrain analysis of tapered silica optical fibers with nanofiber waist  

SciTech Connect

We experimentally determine tensile forceelongation 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 forceelongation 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 stressstrain 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 WienAtominstitut, Stadionallee 2, 1020 Vienna (Austria)

2014-04-21T23:59:59.000Z

298

Laser-driven formation of a high-pressure phase in amorphous silica  

SciTech Connect

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

2002-05-31T23:59:59.000Z

299

Influence of phosphate and silica on U(VI) precipitation from acidic and neutralized wastewaters  

SciTech Connect

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.

2014-04-22T23:59:59.000Z

300

Mesoporous silica nanoparticles in an efficient, solvent-free,green synthesis of acridinediones  

Science Journals Connector (OSTI)

Abstract Mesoporous silica nanoparticles (MSNs) are employedin an efficient, biocompatible and neutralcatalyticgreen synthesis ofacridinediones,throughone-pot three-component reaction of dimedone with aromatic aldehydes, in the presence of a nitrogen source (ammonium acetate or aromatic amines), under neat conditions. There are several advantages for using \\{MSNsinthe\\} current processsuch as good yield, easy catalysis, short reaction time, easy work-up, and simplicity of operation.

Zahra Nasresfahani; M.Z. Kassaee

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "multicomponent geothermometers silica" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Molecular-dynamics simulations of thin polyisoprene films confined between amorphous silica substrates  

SciTech Connect

Constant temperatureconstant 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 polymersilica interactions. The thickness H of the produced PIsilica 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: d.v.guseva@tue.nl [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)

2014-03-21T23:59:59.000Z

302

Improved Adhesion of Dense Silica Coatings on Polymers by Atmospheric Plasma Pretreatment  

Science Journals Connector (OSTI)

Improved Adhesion of Dense Silica Coatings on Polymers by Atmospheric Plasma Pretreatment ... In another study,(7) which compared the treatments of low- and atmospheric-pressure plasmas, the authors reported that the low-pressure plasma treatment increased the adhesion with extended treatment time but prolonged atmospheric-pressure plasma treatment decreased the adhesion to epoxy. ... The authors begin with a brief overview of adhesion theory, and of the physics and chem. of cold plasmas. ...

Linying Cui; Alpana N. Ranade; Marvi A. Matos; Geraud Dubois; Reinhold H. Dauskardt

2013-08-13T23:59:59.000Z

303

Dielectric study of Poly(styrene-co-butadiene) Composites with Carbon Black, Silica, and Nanoclay  

Science Journals Connector (OSTI)

Dielectric study of Poly(styrene-co-butadiene) Composites with Carbon Black, Silica, and Nanoclay ... Given the possible nanoscale dimensions and high surface to volume ratio of the added particles, the glassy interphase can comprise a large fraction of the composite and can strongly influence the mechanical properties of the composite. ... The potential of nanoclays to serve as matrix sensitive structure-directing agents in tailor-made materials is demonstrated. ...

Loan T. Vo; Spiros H. Anastasiadis; Emmanuel P. Giannelis

2011-07-13T23:59:59.000Z

304

Magnetic Silica Nanotubes: Synthesis, Drug Release, and Feasibility for Magnetic Hyperthermia  

Science Journals Connector (OSTI)

Magnetic Silica Nanotubes: Synthesis, Drug Release, and Feasibility for Magnetic Hyperthermia ... After removal of RhB@?-Fe2O3@SiO2 by magnet, 3 mL of the clear solution was extracted with a syringe at given time intervals and then analyzed by UVvis spectroscopy at a wavelength of 4001000 nm. ... The work was supported by Foundation for Polish Science within Focus with contract F4/2010. ...

Xuecheng Chen; Rdiger Klingeler; Matthias Kath; Ahmed A. El Gendy; Krzysztof Cendrowski; Ryszard J. Kalenczuk; Ewa Borowiak-Palen

2012-04-09T23:59:59.000Z

305

Silica coated magnetite nanoparticles for removal of heavy metal ions from polluted waters  

E-Print Network (OSTI)

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

2013-01-01T23:59:59.000Z

306

Detection of alkali-silica reaction swelling in concrete by staining  

DOE Patents (OSTI)

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.

1998-04-14T23:59:59.000Z

307

Detection of alkali-silica reaction swelling in concrete by staining  

DOE Patents (OSTI)

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)

1998-01-01T23:59:59.000Z

308

Surface induced disorder of nematic MBBA near silica with grafted poly(ethylene oxide)  

E-Print Network (OSTI)

909 Surface induced disorder of nematic MBBA near silica with grafted poly(ethylene oxide) H. Ben greffés, du polyoxyde d'ethylene 2000, a été étudié à l'aide des techniques suivantes : la résonance para with grafted polymers poly(ethylene oxide) 2000, has been investigated by the electron paramagnetic resonance

Paris-Sud XI, Université de

309

Energy transfer up-conversion in Tm3+ -doped silica fibre  

E-Print Network (OSTI)

1 Energy transfer up-conversion in Tm3+ - doped silica fibre D. A. Simpson, G. W. Baxter and S. F responsible for the up-conversion: excited state absorption and energy transfer up-conversion. The decay equations, the energy transfer up- conversion process (3 F4,3 F43 H4,3 H6) is established at Tm2O3

Paris-Sud XI, Université de

310

Apparent lattice expansion in ordered nanoporous silica during capillary condensation of fluids  

Science Journals Connector (OSTI)

A Bragg peak shift suggests a pore lattice expansion in ordered nanoporous silica at the onset of capillary condensation of fluids. In depth analysis by a numerical and an analytical approach leads to the conclusion that this shift is due not to a mechanical deformation of the pore lattice but to a subtle interplay between the form factor and the structure factor from crystallites of finite size.

Prass, J.

2012-07-04T23:59:59.000Z

311

Phase behavior of the liquid crystal 8CB in a silica aerogel  

Science Journals Connector (OSTI)

Light scattering and precision calorimetry show that the nematic ordering of octylcyanobiphenyl (8CB) filling the connected network of pores of a silica aerogel does not occur via the first-order phase transition characteristic of the bulk. Rather, ordering is continuous with an orientational correlation length never increasing beyond the aerogel pore size. The heat-capacity anomly of the second-order nematicsmectic-A phase transition seen in the bulk is absent or greatly broadened in the aerogel.

Tommaso Bellini; Noel A. Clark; Chris D. Muzny; Lei Wu; Carl W. Garland; Dale W. Schaefer; Bernard J. Oliver

1992-08-03T23:59:59.000Z

312

Self-fabrication of void array in fused silica by femtosecond laser processing  

SciTech Connect

We demonstrate self-fabrication of a submicrometer-sized void array in fused silica using a 100 fs 0.2-3 {mu}J Ti:Sapphire femtosecond laser and a high 0.9 numerical aperture (NA) objective lens. The effect of the focusing conditions of NA, laser energy, and pulse number on the shape of the fabricated void was investigated. The void has a linearly drawn shape in the direction of the laser irradiation when a single pulse is irradiated and an increasing number of incident pulses resulted in the break up of the long void into multiple spherical ones, leading to a periodically aligned void array. The void shape also varied with the depth of the focus point beneath the fused silica surface, because the amount of self-focusing has a significant effect on the generation of the voids. The void shape was narrower and longer when the laser pulse was focused with the higher NA (up to 0.9) objective lens in the deeper position (up to 70 {mu}m) in the fused silica.

Toratani, Eiji; Kamata, Masanao; Obara, Minoru [Department of Electronics and Electrical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan)

2005-10-24T23:59:59.000Z

313

A New Phenomenon of Compressive Strain Recovery in Gelatin-silica Aerogel Composites with SDS  

Science Journals Connector (OSTI)

Abstract Silica aerogels are nano-structured, highly porous solids with extremely low density but fragile and brittleness. To enhance the applicability of aeorgels, gelatin-silica aerogel (GSA) composite blocks were produced by mixing the hydrophobic aerogel-granules in a gelatin-SDS (sodium dodecyl sulfate) foamed-solution by frothing method. Gelatin essentially acts as binder whereas SDS enhances the foaming capacity of the mixture to the overall binding of the aerogels. The characteristics of these blocks depend on fabrication process and the gelatin-SDS composition. Especially, the strain recovery exhibited after compression is an unusual phenomenon observed with brittle silica aerogels. This paper discusses the effects of SDS on the density and the strain recovery of GSA composites. The fabrication process is explained; compression testing of these blocks is presented and associated strain recovery observed upon unloading is studied. The process variables such amount of gelatin/aerogel/SDS mix; compressive strain; and strain rates were analysed through Analysis of Variance (ANOVA). An empirical model that relates these variables to achieve the optimal strain recovery is established. In addition, the rule of mixture model with a correction factor was developed to estimate the densities of GSA-SDS composites. These composites can be used for heat protection, sound barrier, impact-resistance and shock-absorption.

Mahesh Sachithanadam; Sunil Chandrakanth Joshi

2014-01-01T23:59:59.000Z

314

Production of potentially hazardous respirable silica airborne particulate from the burning of sugarcane  

Science Journals Connector (OSTI)

In some areas of the world where agricultural burning is practised, the airborne particles produced have been linked to respiratory disease in humans. Here, we investigate the abundance and form of silica (SiO2) minerals found within ash and aerosol produced by the experimental burning of sugarcane. Samples of sugarcane leaf were incinerated over a range of temperatures, time scales and airflow conditions, the latter to investigate the effects of wind and updrafts during natural fires. The silica content of the residual ash (from still air simulations) was measured using an improved wet chemical methodology, described here. This indicated that the release of silica from the plant material into the atmosphere increases with increasing temperature of combustion. Airborne particulate, sampled using air-pump-filter apparatus, was characterised using scanning electron microscopy (SEM) with automated image and elemental analysis. For airborne particulate formed at 1100C (with airflow), 17% of the particles are in the respirable size fraction (release of cristobalite to the atmosphere (as sampled on filters). This pilot study shows that potentially toxic particles could be released during sugarcane burning and reinforces the need for further study into the emissions and re-suspension of ash from the burning of biomass.

Jennifer S. Le Blond; Ben J. Williamson; Claire J. Horwell; Alex K. Monro; Caroline A. Kirk; Clive Oppenheimer

2008-01-01T23:59:59.000Z

315

Glucose oxidase enzyme immobilized porous silica for improved performance of a glucose biosensor  

Science Journals Connector (OSTI)

Abstract High activity of glucose oxidase (GOD) enzyme (immobilized in porous silica particles) is desirable for a better glucose biosensor. In this work, effect of pore diameter of two porous hosts on enzyme immobilization, activity and glucose sensing was compared. The hosts were amine functionalized: (i) microporous silica (NH2-MS) and (ii) mesoporous silica (NH2-SBA-15). Based on whether the dimension of GOD is either larger or smaller than the pore diameter, GOD was immobilized on either external or internal surface of NH2-MS and NH2-SBA-15, with loadings of 512.5 and 634mg/g, respectively. However, GOD in NH2-SBA-15 gave a higher normalized absolute activity (NAA), which led to an amperometric sensor with a larger linear range of 0.413.0mM glucose. In comparison, GOD in NH2-MS had a lower NAA and a smaller linear range of 0.43.1mM. In fact, the present GOD-NH2-SBA-15 electrode based sensor was better than other MS and SBA-15 based electrodes reported in literature. Thus, achieving only a high GOD loading (as in NH2-MS) does not necessarily give a good sensor performance. Instead, a host with a relatively larger pore than enzyme, together with optimized electrode composition ensures the sensor to be functional in both hyper- and hypoglycemic range.

Anees Y. Khan; Santosh B. Noronha; Rajdip Bandyopadhyaya

2014-01-01T23:59:59.000Z

316

Controlled epitaxial growth of mesoporous silica/gold nanorod nanolollipops and nanodumb-bells  

SciTech Connect

In this work, we describe the controlled synthesis of novel heterogeneous nanostructures comprised of mesoporous silica-coated gold nanorods (MSGNRs) in the form of coreshell nanolollipops and nanodumb-bells, using a seed-mediated solgel method. Although MSGNR coreshell (?-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: lwlo@nhri.org.tw [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)

2014-11-01T23:59:59.000Z

317

Sorption Behavior of Strontium-85 Onto Colloids of Silica and Smectite  

SciTech Connect

Strontium-90 is one of the sizable radioactive contaminants found in DP Canyon at Los Alamos, New Mexico. Radioactive surveys found the {sup 90}Sr is present in surface and groundwater in DP Canyon and Los Alamos Canyon. Colloids may influence the transport of this radionuclide in surface water and groundwater environments in both canyons. In this study, we investigated the sorption/desorption behavior of Sr on colloids of smectite and silica. Laboratory batch sorption experiments were conducted using {sup 85}Sr as a surrogate to {sup 90}Sr. Groundwater, collected from DP Canyon and from Well J-13 at Yucca Mountain, Nevada, and deionized water were used in this study. Our results show that 92% to 100% of {sup 85}Sr was rapidly adsorbed onto smectite colloids in all three waters. The concentrations of Ca{sup 2+} significantly influence the adsorption of {sup 85}Sr onto silica colloids. Desorption of {sup 85}Sr from smectite colloids is much slower than the sorption process. Desorption of {sup 85}Sr from silica colloids was rapid in DP groundwater and slow using J-13 groundwater and deionized water.

Lu, N.; Triay, I.R.; Mason, C.F.V.; Longmire, P.A.

1998-11-10T23:59:59.000Z

318

Silica Polyamine Composites: New Supramolecular Materials for Cation and Anion Recovery and Remediation  

SciTech Connect

The surface coverage of amorphous silica gels used in the synthesis of silica polyamine composites has been investigated by 29Si NMR. By diluting the polyamine anchor silane, chloropropyl trichlorosilane, with methyl trichlorosilane it was found that surface coverage could be markedly improved for a range of amine polymers after grafting to the silica surface. The commensurate decrease in the number of anchor points and increase in the number of free amines results in an increase in metal capacity and/or an improvement in capture kinetics. Solid state CPMAS-13C NMR has been employed to investigate the structure and metal ion binding of a series of these composite materials. It is reported that the highly branched polymer, poly(ethyleneimine) (PEI) exhibits much broader 13C NMR resonances than the linear polymers poly(allylamine) (PAA) and poly(vinylamine) (PVA). These results are understood in terms of the low energy conformations calculated from molecular modeling studies. Three new applications of the technology are also presented: (1) separation of lanthanides as a group from ferric ion and all other divalent ions; (2) a multi step process for recovering and concentrating the valuable metals in acid mine drainage; (3) a process for removing low level arsenic and selenium in the presence of sulfate using immobilized cations on the composite materials.

Hughes, Mark; Miranda, Paul; Nielsen, Daniel J.; Rosenberg, Edward; Gobetto, Roberto; Viale, Alessandra; Burton, Sarah D.

2006-03-01T23:59:59.000Z

319

Preparation of frustule-like 1,2-ethylene-silica nanospheres through a chiral amphiphile/organic solvent dual-templating approach  

SciTech Connect

Graphical abstract: Display Omitted Highlights: ? Frustule-like 1,2-ethylene-silicas were prepared through a dual-templating approach. ? The morphologies and pore architectures of the 1,2-ethylene-silicas are tunable. ? Mesoporous 1,2-ethylene-silica nanotubes were also prepared. -- Abstract: Hollow silica nanospheres with mesopores in the walls have been widely studied because of their potential applications in catalysis and drug release. Hollow organosilica nanospheres also attracted much attention because of their tunable wall backbones and wider applications. Herein, frustule-like 1,2-ethylene-silicas were obtained using a chiral amphiphile, CHCl{sub 3}, and a dual-templating approach. The morphologies and pore architectures of the 1,2-ethylene-silicas are tunable by changing the amount of CHCl{sub 3} in the reaction mixture. With the addition of CHCl{sub 3} in the reaction mixtures, hollow 1,2-ethylene-silica nanospheres with opened mesopores in the walls were feasible. Moreover, 1,2-ethylene-silicas with mesopores on the surfaces and coiled pore channels within the walls were obtained using the chiral amphiphile in a single-templating approach. These 1,2-ethylene-silicas were characterized using field-emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction and N{sub 2} sorptions.

Zhao, Yanwei; Huang, Zhibin; Yan, Zhuojun; Wang, Sibing; Li, Baozong [Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, Department of Polymer Science and Engineering, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China)] [Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, Department of Polymer Science and Engineering, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Li, Yi, E-mail: liyi@suda.edu.cn [Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, Department of Polymer Science and Engineering, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China)] [Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, Department of Polymer Science and Engineering, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Yang, Yonggang [Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, Department of Polymer Science and Engineering, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China)] [Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, Department of Polymer Science and Engineering, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China)

2013-02-15T23:59:59.000Z

320

Role of relative humidity in concrete expansion due to alkali-silica reaction and delayed ettringite formation: relative humidity thresholds, measurement methods, and coatings to mitigate expansion.  

E-Print Network (OSTI)

??Premature concrete deterioration due to alkali-silica reaction (ASR) and delayed ettringite formation (DEF) is a significant problem all over the world. In cases where these (more)

Rust, Charles Karissa

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "multicomponent geothermometers silica" from the National Library of EnergyBeta (NLEBeta).
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321

Enhancement of T1 and T2 relaxation by paramagnetic silica-coated nanocrystals  

SciTech Connect

We present the first comprehensive investigation on water-soluble nanoparticles embedded into a paramagnetic shell and their properties as an MRI contrast agent. The nanoprobes are constructed with an inorganic core embedded into an ultra-thin silica shell covalently linked to chelated Gd{sup 3+} paramagnetic ions that act as an MRI contrast agent. The chelator contains the molecule DOTA and the inorganic core contains a fluorescent CdSe/ZnS qdots in Au nanoparticles. Optical properties of the cores (fluorescence emission or plasmon position) are not affected by the neither the silica shell nor the presence of the chelated paramagnetic ions. The resulting complex is a MRI/fluorescence probe with a diameter of 8 to 15 nm. This probe is highly soluble in high ionic strength buffers at pH ranging from {approx}4 to 11. In MRI experiments at clinical field strengths of 60 MHz, the QDs probes posses spin-lattice (T{sub 1}) and a spin-spin (T{sub 2}) relaxivities of 1018.6 +/- 19.4 mM{sup -1} s{sup -1} and 2438.1 +/- 46.3 mM{sup -1} s{sup -1} respectively for probes having {approx}8 nm. This increase in relaxivity has been correlated to the number of paramagnetic ions covalently linked to the silica shell, ranging from approximately 45 to over 320. We found that each bound chelated paramagnetic species contributes by over 23 mM{sup -1} s{sup -1} to the total T{sub 1} and by over 54 mM{sup -1} s{sup -1} to the total T{sub 2} relaxivity respectively. The contrast power is modulated by the number of paramagnetic moieties linked to the silica shell and is only limited by the number of chelated paramagnetic species that can be packed on the surface. So far, the sensitivity of our probes is in the 100 nM range for 8-10 nm particles and reaches 10 nM for particles with approximately 15-18 nm in diameter. The sensitivities values in solutions are equivalent of those obtained with small superparamagnetic iron oxide nanoparticles of 7 nm diameter clustered into a 100 nm polymeric shell. A thin paramagnetic silica shell as interface with the bioworld presents several advantages over polymeric coating or dendrimers in terms of in vivo biocompatibility and ease of functionalization with targeting biomolecules. Theoretically, these relaxivity values are high enough to be detected by MRI of a single cell labeled with 10{sup 5} probes. We briefly discuss the importance of probes coated with a paramagnetic silica shell for the detection and treatment of diseases in vivo.

Gerion, D; Herberg, J; Gjersing, E; Ramon, E; Maxwell, R; Gray, J W; Budinger, T F; Chen, F F

2006-08-28T23:59:59.000Z

322

Mesoporous Silica Nanomaterials for Applications in Catalysis, Sensing, Drug Delivery and Gene Transfection  

SciTech Connect

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

2005-12-19T23:59:59.000Z

323

Water purification by functionalised self-assembled monolayers on silica particles  

Science Journals Connector (OSTI)

This study focuses on a novel method to remove bio molecules and pathogens of different nature, such as proteins, viruses and oocysts, from water by silica particles coated with functionalised self-assembled monolayers. The results clearly show that organic species can efficiently be removed at pH ranges of drinking water by stirring the coated particles in the contaminated water for up to 60 min and finally filtering the powder. The removal is believed to be caused by electrostatic attraction and immobilisation of pathogens on the surface of the particles. At higher pH values above about 8, even chemisorption may occur.

Peter J. Majewski; Chiu Ping Chan

2008-01-01T23:59:59.000Z

324

Effect of Support Corrugation on Silica Xerogel?Supported Phase-Separated Lipid Bilayers  

Science Journals Connector (OSTI)

Furthermore, the lateral mobility of the lipids was confirmed for lipid bilayers supported by porous silica xerogel and aerogel surfaces. ... The fluorescence recovery images were captured with the excitation light that was attenuated at least 400 times (by the use of neutral density filters) to prevent further bleaching. ... The emission light was filtered by a 568 nm notch filter (Kaiser Optical Systems, Ann Arbor, MI) and a confocal pinhole (50 ?m diameter, Thorlabs, Newton, NJ) and then split by a 50/50 beam-splitter before finally being focused into two avalanche photo diodes (APD) (PerkinElmer). ...

Emel I. Goksu; Barbara A. Nellis; Wan-Chen Lin; Joe H. Satcher, Jr.; Jay T. Groves; Subhash H. Risbud; Marjorie L. Longo

2009-02-11T23:59:59.000Z

325

Applications for silica-based aerogel products on an industrial scale  

SciTech Connect

Aerogels, nanoporous lightweight materials, were discovered more than 60 years ago. The supercritical manufacturing process and expensive raw materials typically used to produce aerogels prohibited commercialization on an industrial scale. Recently a commercially attractive ambient pressure production process was developed which will allow broader commercialization of silica-aerogel products. Some aerogel products for insulation applications and their preparation are described. Sound insulation properties including a remarkable absorption in the difficult low frequency range was found. In the case of insulation plates performance depends on binder and can be positively influenced by choosing the right binding material.

Schmidt, M.; Schwertfeger, F. [Hoechst Research and Technology Deutschland GmbH and Co., Frankfurt/Main (Germany)

1998-12-31T23:59:59.000Z

326

Click Synthesis of Monolithic Silicon Carbide Aerogels from Polyacrylonitrile-Coated 3D Silica Networks  

Science Journals Connector (OSTI)

Monolithic highly porous (70% v/v) SiC aerogels are synthesized carbothermally from X-PAN-SiO2, i.e., monolithic silica aerogels are prepared and coated in one pot with a conformal poly acrylonitrile coating via a surface-initiated free radical process. ... Conformal PAN coatings would be obtained with other surface-confined initiators, including monodentate ones. ... An aerogel-like composite material was synthesized by casting a conformal 4-6 nm diisocyanate-derived polymer coating on the bird-nest like skeletal framework of mesoporous vanadia consisting of entangled 100-200 nm long, 30-40 nm thick worm-like objects. ...

Nicholas Leventis; Anand Sadekar; Naveen Chandrasekaran; Chariklia Sotiriou-Leventis

2010-03-23T23:59:59.000Z

327

Structural Investigations of Silica Polyamine Composites: Surface Coverage, Metal Ion Coordination, and Ligand Modification  

SciTech Connect

Silanization of the silica gel surface in the synthesis of silica gel polyamine composites uses (chloropropyl)-trichlorosilane (CPTCS). It is possible to substitute a molar fraction of reagent CPTCS with methyltrichlorosilane (MTCS), creating a mixed silane surface layer. Two types of silica gels were modified with a series of MTCS:CPTCS molar ratios. Solid-state CP/MAS 29Si and 13C NMR spectroscopies were used to evaluate the surface silane composition. Surface silane coverage was markedly improved for the resulting gels. When polyamines were grafted to the resultant MTCS:CPTCS silane layers, it was shown that the decrease in the number of propyl attachments to the polyamine resulted in increased quantities of ''free amines''. Optimum MTCS:CPTCS ratios were determined for three polyamines grafted onto one silica gel. A substantial free amine increase was observed for poly(allylamine) (PAA). Metal uptake studies show increases in Cu(II) capacity and/or an improvement in Cu(II) mass-transfer kinetics. The effect of polymer molecular weight upon Cu(II) capacity was investigated for each polyamine. Substantial differences in Cu(II) capacity between 50,000 MW poly(vinylamine) (PVA) and >1000 MW PVA were evident. Similar differences between 25,000 MW poly(ethyleneimine) (PEI) and 1200 MW PEI were found. The mass-transfer kinetics was shown to be improved for composites prepared using a large fraction of MTCS in the reagent silane mixture. This resulted in substantial improvements in the 10% breakthrough Cu(II) capacity for PVA (50 000 MW). PEI composites were further modified to form an amino-acetate ligand. The impact of the MTCS:CPTCS silane ratio on the acetate ligand loading and ultimately on the Cu(II) capacity at pH 2 was investigated. A ratio of 12.5:1 was shown to result in an acetate modified PEI composite with a Cu(II) capacity 140% of the Cu(II) capacity of the same composite prepared with ''CPTCS only''.

Hughes, Mark; Nielsen, Daniel; Rosenberg, Edward; Gobetto, Roberto; Viale, Alessandra; Burton, Sarah D.; Ferel, Joseph

2006-09-13T23:59:59.000Z

328

X-ray spectroscopy study of electronic structure of laser-irradiated Au nanoparticles in a silica film  

SciTech Connect

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)

2005-03-15T23:59:59.000Z

329

S9 -Kinetics & Mechanism of Metal Sorption/Release on Natural Materials ADSORPTION MECHANISMS OF PB ON AMORPHOUS SILICA: AN XAS  

E-Print Network (OSTI)

S9 - Kinetics & Mechanism of Metal Sorption/Release on Natural Materials ADSORPTION MECHANISMS the sorption behavior and mechanisms of Pb on amorphous silica using X-ray absorption spectroscopy (XAS t h o d s Pb sorption on silica was studied as a function of pH. The pH range used was pH 3

Sparks, Donald L.

330

Nanocasting:? Using SBA-15 Silicas as Hard Templates to Obtain Ultrasmall Monodispersed ?-Fe2O3 Nanoparticles  

Science Journals Connector (OSTI)

To avoid the growth of large FeOx iron oxide particles outside the silica grains, the iron precursor (iron nitrate) is deposited inside the mesopores of SBA-15 silicas using the two-solvents technique already described elsewhere and successfully applied to other oxides (manganese oxides, for instance25). ... 11 These nanoparticles are further oxidized by ferric nitrate in nitric acid and yield to cationic maghemite nanoparticles dispersible in nitric acid at pH 1.2. ... Figure 5 Raman spectra of selected references (Fe-SBA-B-1373,3-53 for epsilon, commercial hematite, dried ferrofluid for ? varieties; Fe-loaded SBA-B samples. ...

E. Delahaye; V. Escax; N. El Hassan; A. Davidson; R. Aquino; V. Dupuis; R. Perzynski; Y. L. Raikher

2006-11-22T23:59:59.000Z

331

Molecular dynamics simulation of shock induced ejection on fused silica surface  

SciTech Connect

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: jun-chen@iapcm.ac.cn [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)

2014-05-21T23:59:59.000Z

332

Power scaling analysis of fiber lasers and amplifiers based on non-silica materials  

SciTech Connect

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

2010-03-30T23:59:59.000Z

333

Improving the Monitoring, Verification, and Accounting of CO{sub 2} Sequestered in Geologic Systems with Multicomponent Seismic Technology and Rock Physics Modeling  

SciTech Connect

Research done in this study showed that P-SV seismic data provide better spatial resolution of geologic targets at our Appalachian Basin study area than do P-P data. This finding is important because the latter data (P-P) are the principal seismic data used to evaluate rock systems considered for CO{sub 2} sequestration. The increase in P-SV{sub 1} resolution over P-P resolution was particularly significant, with P-SV{sub 1} wavelengths being approximately 40-percent shorter than P-P wavelengths. CO{sub 2} sequestration projects across the Appalachian Basin should take advantage of the increased resolution provided by converted-shear seismic modes relative to P-wave seismic data. In addition to S-wave data providing better resolution of geologic targets, we found S-wave images described reservoir heterogeneities that P-P data could not see. Specifically, a channel-like anomaly was imaged in a key porous sandstone interval by P-SV{sub 1} data, and no indication of the feature existed in P-P data. If any stratigraphic unit is considered for CO{sub 2} storage purposes, it is important to know all heterogeneities internal to the unit to understand reservoir compartmentalization. We conclude it is essential that multicomponent seismic data be used to evaluate all potential reservoir targets whenever a CO{sub 2} storage effort is considered, particularly when sequestration efforts are initiated in the Appalachian Basin. Significant differences were observed between P-wave sequences and S- wave sequences in data windows corresponding to the Oriskany Sandstone, a popular unit considered for CO{sub 2} sequestration. This example demonstrates that S-wave sequences and facies often differ from P-wave sequences and facies and is a principle we have observed in every multicomponent seismic interpretation our research laboratory has done. As a result, we now emphasis elastic wavefield seismic stratigraphy in our reservoir characterization studies, which is a science based on the concept that the same weight must be given to S-wave sequences and facies as is given to P-wave sequences and facies. This philosophy differs from the standard practice of depending on only conventional P-wave seismic stratigraphy to characterize reservoir units. The fundamental physics of elastic wavefield seismic stratigraphy is that S- wave modes sense different sequences and facies across some intervals than does a P-wave mode because S-wave displacement vectors are orthogonal to P- wave displacement vectors and thus react to a different rock fabric than do P waves. Although P and S images are different, both images can still be correct in terms of the rock fabric information they reveal.

Alkan, Engin; DeAngelo, Michael; Hardage, Bob; Sava, Diana; Sullivan, Charlotte; Wagner, Donald

2012-12-31T23:59:59.000Z

334

Geothermometry At Long Valley Caldera Area (Sorey, Et Al., 1991) | Open  

Open Energy Info (EERE)

Long Valley Caldera Area (Sorey, Et Long Valley Caldera Area (Sorey, Et Al., 1991) Exploration Activity Details Location Long Valley Caldera Area Exploration Technique Geothermometry Activity Date Usefulness could be useful with more improvements DOE-funding Unknown Notes Silica-geothermometer temperature estimates for the Casa Diablo and RDO-8 well samples ( 196-202 degrees C) are lower than the corresponding cation-geothermometer temperature estimates, indicating loss of silica with declining reservoir temperature or dilution with low-silica waters. At shallow depths in the caldera References Michael L. Sorey, Gene A. Suemnicht, Neil C. Sturchio, Gregg A. Nordquist (1991) New Evidence On The Hydrothermal System In Long Valley Caldera, California, From Wells, Fluid Sampling, Electrical Geophysics, And

335

Direct One-Step Immobilization of Glucose Oxidase in Well-Ordered Mesostructured Silica Using a Nonionic Fluorinated Surfactant  

Science Journals Connector (OSTI)

This work describes the immobilization of glucose oxidase (GOD) in mesostructured silica. ... The appearance of secondary or interparticular porosity has been correlated with the SEM observations that show the formation of very small particles with increasing pH values of the synthesis gel. ... With the 2nd method both the nanostructure and the particle morphol. ...

J. L. Blin; C. Grardin; C. Carteret; L. Rodehser; C. Selve; M. J. Stb

2005-02-25T23:59:59.000Z

336

Hydrothermal Growth of Mesoporous SBA-15 Silica in the Presence of PVP-Stabilized Pt Nanoparticles: Synthesis,  

E-Print Network (OSTI)

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

Yang, Peidong

337

Ultra-large bandwidth hollow-core guiding in all-silica Bragg fibers with nano-supports  

E-Print Network (OSTI)

in the literature. With only three rings of silica cladding layers, these Bragg fibers achieve propagation loss, "Wavelength-scalable hollow optical fibres with large photonic bandgaps for CO2 laser transmission," Nature cladding structures for air-core photonic bandgap fibers." Opt. Lett. 29, 349-351 (2004). 12. T. P. White

Huang, Yanyi

338

Ostwald ripening of cobalt precipitates in silica aerogels? An ultra-small-angle X-ray scattering study  

Science Journals Connector (OSTI)

Silica aerogels were doped with cobalt, reduced, and studied with ultra-small-angle X-ray scattering. A scattering pattern rich in structure extends over nearly four orders of magnitude in q space, covering real space from 5 to 3000 ?, exposing micropores, mesopores and macropores for all aerogels.

Braun, A.

2005-01-19T23:59:59.000Z

339

Atomistic simulation of the interface structure of Si nanocrystals embedded in amorphous silica Flyura Djurabekova and Kai Nordlund*  

E-Print Network (OSTI)

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

340

Replication of butterfly wing and natural lotus leaf nanostructures by nanoimprint on Silica Sol-gel films.  

E-Print Network (OSTI)

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

Note: This page contains sample records for the topic "multicomponent geothermometers silica" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Benign, 3D encapsulation of sensitive mammalian cells in porous silica gels formed by LysSil nanoparticle assembly  

E-Print Network (OSTI)

­Sil nanoparticle assembly Mark A. Snyder, Döne Demirgöz, Efrosini Kokkoli *, Michael Tsapatsis * Department 2008 Keywords: Silica gels Nanoparticles Mammalian cell encapsulation Laser scanning confocal nanoparticles in aqueous solutions of the basic amino acid L-Lysine for encapsulation of living mammalian cells

Kokkoli, Efie

342

Heterogeneous Photocatalytic Remediation of Phenol by Platinized TitaniaSilica Mixed Oxides under Solar-Simulated Conditions  

Science Journals Connector (OSTI)

Heterogeneous Photocatalytic Remediation of Phenol by Platinized TitaniaSilica Mixed Oxides under Solar-Simulated Conditions ... In recent years, innovative research for the development of advanced products has realized nanomaterials that demonstrate the unique structural, mechanical, optical, electronic, and catalytic properties under light irradiation. ...

Harrison S. Kibombo; Ranjit T. Koodali

2011-11-28T23:59:59.000Z

343

Borosilicate clad fused silica core fiber optical waveguide with low transmission loss prepared by a high?efficiency process  

Science Journals Connector (OSTI)

A method for making fused silica core?borosilicate clad optical fiberwaveguides is described. The process involves the growth of a needlelike layer of borosilicate glass onto the surface of a commercially available high?purity fused silica rod by an efficient flamereaction of boron and silicon hydrides with oxygen. The needlelike layer is subsequently heat treated at relatively low temperature to form a homogeneous bubble?free glass with a smooth surface. It is then covered with a thin protective jacket of silica and drawn into a fiber. These fibers have attenuation coefficients only slightly greater than the bulk loss of the fused silica core materials. Over the Al1?x Ga x As injection laser wavelength range 0.820.88 ?m the loss is 5 dB/km while at the YAG : Nd laser wavelength 1.06 ?m it is 3 dB/km. The process appears to be attractive for the economical manufacture of low?loss fibers due to its simplicity and high chemical conversion efficiency.

F. W. Dabby; D. A. Pinnow; F. W. Ostermayer; L. G. Van Uitert; M. A. Saifi; I. Camlibel

1974-01-01T23:59:59.000Z

344

Surface Complexation Model for Strontium Sorption to Amorphous Silica and Goethite  

SciTech Connect

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

2007-11-30T23:59:59.000Z

345

A New Concept for the Fabrication of Hydrogen Selective Silica Membranes  

NLE Websites -- All DOE Office Websites (Extended Search)

New CoNCept for the fAbriCAtioN of New CoNCept for the fAbriCAtioN of hydrogeN SeleCtive SiliCA MeMbrANeS Background As stated in the National Research Council report on Novel Approaches to Carbon Management, a novel membrane is needed that can achieve the separation of carbon dioxide (CO 2 ) and hydrogen (H 2 ) at a high temperature and pressure. Extensive efforts over the last several decades have explored high temperature H 2 -selective membranes made of silicon dioxide (SiO 2 ) and other oxides, palladium (Pd) and other metals or alloys and, more recently, various zeolites and non-aluminosilicate molecular sieves. Although promising separation results have been reported for many of them, these technologies, they all suffer from high production costs for membrane fabrication and from long term stability problems. This project revisits

346

Post-Harvest Processing Methods for Reduction of Silica and Alkali Metals in Wheat Straw  

SciTech Connect

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 950C 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

2002-04-01T23:59:59.000Z

347

Aminosilane-Grafted Polymer/Silica Hollow Fiber Adsorbents for CO2 Capture from Flue Gas  

Science Journals Connector (OSTI)

In this approach, polymeric hollow fibers similar to those already prepared on commercial scales for membrane gas separations are prepared and loaded with large volumes of solid CO2 adsorbing materials. ... In this regard, the hollow fiber RTSA process is ideally suited for application of typical silica amine adsorbents, as it (i) allows for effective heat integration,(11) (ii) gives fast cycle times (expected to be on the order of 24 min),(8) and (iii) minimizes contact of aminosilica-adsorbents with high-temperature steam, which can degrade the adsorbent. ... The moles of CO2 adsorbed were calculated by integration of the area bounded by the CO2 breakthrough front and the He breakthrough front from the initial concentration to the final equilibration concentration. ...

Fateme Rezaei; Ryan P. Lively; Ying Labreche; Grace Chen; Yanfang Fan; William J. Koros; Christopher W. Jones

2013-03-29T23:59:59.000Z

348

A molecular dynamics investigation of the unusual concentration dependencies of Fick diffusivities in silica mesopores  

SciTech Connect

Molecular Dynamics (MD) simulations were carried out to determine the self-diffusivitiy, D{sub i,self}, the MaxwellStefan 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

2011-01-01T23:59:59.000Z

349

Adsorption and methanation of carbon dioxide on a nickel/silica catalyst  

SciTech Connect

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.

1980-04-01T23:59:59.000Z

350

Dynamics at the Polymer/Nanoparticle Interface in Poly(2-vinylpyridine)/Silica Nanocomposites.  

SciTech Connect

The static and dynamic properties of poly(2-vinylpyridine)/silica nanocomposites are investigated by temperature modulated differential scanning calorimetry, broadband dielectric spectroscopy (BDS), small-angle X-ray scattering (SAXS), and transmission electron microscopy. Both BDS and SAXS detect the existence of an interfacial polymer layer on the surface of nanoparticles. The results show that whereas the calorimetric glass transition temperature varies only weakly with nanoparticle loading, the segmental mobility of the polymer interfacial layer is slower than the bulk polymer by 2 orders of magnitude. Detailed analysis of BDS and SAXS data reveal that the interfacial layer has a thickness of 4 6 nm irrespective of the nanoparticle concentration. These results demonstrate that in contrast to some recent articles on polymer nanocomposites, the interfacial polymer layer is by no means a dead layer . However, its existence might provide some explanation for controversies surrounding the dynamics of polymer nanocomposites.

Holt, Adam P [ORNL] [ORNL; Griffin, Phillip [University of Tennessee (UTK) and Oak Ridge National Laboratory (ORNL)] [University of Tennessee (UTK) and Oak Ridge National Laboratory (ORNL); Bocharova, Vera [ORNL] [ORNL; Agapov, Alexander L [ORNL] [ORNL; Imel, Adam E [ORNL] [ORNL; Dadmun, Mark D [ORNL] [ORNL; Sangoro, Joshua R [ORNL] [ORNL; Sokolov, Alexei P [ORNL] [ORNL

2014-01-01T23:59:59.000Z

351

Ultrafast laser induced electronic and structural modifications in bulk fused silica  

SciTech Connect

Ultrashort laser pulses can modify the inner structure of fused silica, generating refractive index changes varying from soft positive (type I) light guiding forms to negative (type II) values with void presence and anisotropic sub-wavelength modulation. We investigate electronic and structural material changes in the type I to type II transition via coherent and incoherent secondary light emission reflecting free carrier behavior and post-irradiation material relaxation in the index change patterns. Using phase contrast microscopy, photoluminescence, and Raman spectroscopy, we determine in a space-resolved manner defect formation, redistribution and spatial segregation, and glass network reorganization paths in conditions marking the changeover between type I and type II photoinscription regimes. We first show characteristic patterns of second harmonic generation in type I and type II traces, indicating the collective involvement of free carriers and polarization memory. Second, incoherent photoemission from resonantly and non-resonantly excited defect states reveals accumulation of non-bridging oxygen hole centers (NBOHCs) in positive index domains and oxygen deficiency centers (ODCs) with O{sub 2}{sup ?} ions segregation in void-like regions and in the nanostructured domains, reflecting the interaction strength. Complementary Raman investigations put into evidence signatures of the different environments where photo-chemical densification (bond rearrangements) and mechanical effects can be indicated. NBOHCs setting in before visible index changes serve as precursors for subsequent compaction build-up, indicating a scenario of cold, defect-assisted densification for the soft type I irradiation regime. Additionally, we observe hydrodynamic effects and severe bond-breaking in type II zones with indications of phase transition. These observations illuminate densification paths in fused silica in low power irradiation regimes, and equally in energetic ranges, characterized by the onset of thermo-mechanical effects.

Mishchik, K.; D'Amico, C.; Velpula, P. K.; Mauclair, C.; Boukenter, A.; Ouerdane, Y.; Stoian, R. [Laboratoire Hubert Curien, UMR 5516 CNRS, Universit de Lyon, Universit Jean Monnet, 42000 Saint Etienne (France)] [Laboratoire Hubert Curien, UMR 5516 CNRS, Universit de Lyon, Universit Jean Monnet, 42000 Saint Etienne (France)

2013-10-07T23:59:59.000Z

352

Treatment and prevention of ARD using silica micro encapsulation[Acid Rock Drainage  

SciTech Connect

In response to the known drawbacks of liming and the ever-increasing regulatory demands on the mining industry, KEECO has developed a silica micro encapsulation (SME) process. SME is a cost-effective, high performance reagent that is utilized in conjunction with simple chemical delivery systems. By encapsulating metals in a silica matrix formation and rapidly precipitating them into a sand-like sludge, it offers all the advantages of liming without the negative drawbacks. Utilizing an injection technique via a high shear mixing device, a slurry form of the SME product called KB-1{trademark} was applied to ARD at the Bunker Hill Mine in Idaho and to ARD pumped from collection ponds at a remote mine site in the Sierra Nevada Mountains. Flow rates at both sites ranged form 500 to 800 gallons per minute. Treated water from the Bunker Hill Mine operation achieved the site's NPDES criteria for all evaluated metals and US Drinking Water quality for arsenic, cadmium, chromium, lead and zinc with a dosage rate of 1.34 grams KB-1{trademark} per liter. Treated water from the Sierra Nevada project focused on the control of aluminum, arsenic, copper, iron and nickel. All water samples displayed a >99.5% reduction in these metals, as well as an 84%--87% reduction in the concentration of sulfate. Testing on sludge generated form both operations achieved TCLP Action Limits. The SME process is currently under evaluation as a means to coat the pyrite surfaces of newly generated mine tailings to prevent oxidation and future acid generation.

Mitchell, P.; Rybock, J.; Wheaton, A.

1999-07-01T23:59:59.000Z

353

Comparison of the morphology of alkalisilica gel formed in limestones in concrete affected by the so-called alkalicarbonate reaction (ACR) and alkalisilica reaction (ASR)  

SciTech Connect

The morphology of alkalisilica gel formed in dolomitic limestone affected by the so-called alkalicarbonate reaction (ACR) is compared to that formed in a siliceous limestone affected by alkalisilica reaction (ASR). The particle of dolomitic limestone was extracted from the experimental sidewalk in Kingston, Ontario, Canada that was badly cracked due to ACR. The siliceous limestone particle was extracted from a core taken from a highway structure in Quebec, affected by ASR. Both cores exhibited marked reaction rims around limestone particles. The aggregate particles were polished and given a light gold coating in preparation for examination in a scanning electron microscope. The gel in the ACR aggregate formed stringers between the calcite crystals in the matrix of the rock, whereas gel in ASR concrete formed a thick layer on top of the calcite crystals, that are of the same size as in the ACR aggregate.

Grattan-Bellew, P.E., E-mail: p.grattan-bellew@sympatico.ca [Materials and Petrographic Research G-B Inc., 472 Edison Avenue, Ottawa, ON, Canada K2A 1T9 (Canada); Chan, Gordon [NRC Construction, Bldg., M20, 1200 Montreal Road, Ottawa, ON, Canada K1A 0R6 (Canada)] [NRC Construction, Bldg., M20, 1200 Montreal Road, Ottawa, ON, Canada K1A 0R6 (Canada)

2013-05-15T23:59:59.000Z

354

Synthesis of antibodies-conjugated fluorescent dye-doped silica nanoparticles for a rapid single step detection of campylobacter jejuni in live poultry  

Science Journals Connector (OSTI)

The preparation of antibodies-conjugated fluorescent dye-doped silica nanoparticles (FDS-NPs) was developed to detect Campylobacter jejuni cells under a fluorescence microscope. The particles prepared by sol-gel microemulsion techniques have a round ...

Wachira Tansub; Kooranee Tuitemwong; Pichet Limsuwan; Supannee Theparoonrat; Pravate Tuitemwong

2012-01-01T23:59:59.000Z

355

Improvement of Radiation-Induced Degradation in MOSFET by Using Glass Fiber/Epoxy/Silica Nanoparticles/?-APTES Composite as Shielding Materials for High-Energy Radiation  

Science Journals Connector (OSTI)

Our recent study showed that the trapping charges of the polysilicon wire sensor caused by ?-ray radiation primarily concentrated in the ?-APTES/silica nanoparticles composite layer covered on the sensor. In this...

Po-Yen Hsu; Shou-Sheu Lin; Cheng-Fu Yang

2013-01-01T23:59:59.000Z

356

Correlation of defect centers with second-harmonic generation in Ge-doped and GeP-doped silica-core single-mode fibers  

Science Journals Connector (OSTI)

The origin of frequency doubling in Ge-doped silica-core single-mode glass fibers has been investigated with electron-spin-resonance spectrometry. Correlations have been observed...

Tsai, T E; Saifi, M A; Friebele, E J; sterberg, U; Griscom, D L

1989-01-01T23:59:59.000Z

357

Interstitial BiO molecule as a broadband IR luminescence centre in bismuth-doped silica glass  

SciTech Connect

Experimental data on absorption and luminescence in optical fibres with a Bi : SiO{sub 2} glass core are compared to experimentally determined and calculated spectroscopic properties of the BiO molecule. The results suggest that the IR luminescence of Bi : SiO{sub 2} glass is due to interstitial BiO molecules. This assumption is supported by quantum-chemical simulation results for a BiO molecule in a ring interstice of the silica glass network.

Sokolov, V O; Plotnichenko, V G; Dianov, Evgenii M [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation)

2011-12-31T23:59:59.000Z

358

BIMETALLIC NANOCATALYSTS IN MESOPOROUS SILICA FOR HYDROGEN PRODUCTION FROM COAL-DERIVED FUELS  

SciTech Connect

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

2013-02-13T23:59:59.000Z

359

Differences in pulmonary responses of rats, other animals, and humans to chronic inhalation of silica and other particles  

SciTech Connect

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.

1993-12-31T23:59:59.000Z

360

Enthalpy Diffusion in Multicomponent Flows  

SciTech Connect

The conclusions of this paper are: (1) Enthalpy diffusion preserves the second law. (2) Euler solvers will not produce correct temperatures in mixing regions. (3) Navier-Stokes solvers will only produce correct temperatures if q{sub d} is included. (4) Errors from neglecting enthalpy diffusion are most severe when differences in molecular weights are large. (5) In addition to temperature, enthalpy diffusion affects density, dilatation and other fields in subtle ways. (6) Reacting flow simulations that neglect the term are a dubious proposition. (7) Turbulence models for RANS and LES closures should preserve consistency between energy and species diffusion.

Cook, A W

2009-01-20T23:59:59.000Z

Note: This page contains sample records for the topic "multicomponent geothermometers silica" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Precision measurements of binary and multicomponent diffusion coefficients in protein solutions relevant to crystal growth: Lysozyme chloride in water and aqueous NaCl at pH 4.5 and 25{degree}C  

SciTech Connect

Accurate models of protein diffusion are important in a number of applications, including liquid-liquid phase separation and growth of protein crystals for X-ray diffraction studies. In concentrated multicomponent protein systems, significant deviations from pseudobinary behavior can be expected. Rayleigh interferometry is used to measure the four elements (D{sub if}){sub v} of the ternary diffusion coefficient matrix for the extensively investigated protein, hen egg-white lysozyme (component 1) in aqueous NaCl (component 2) at pH 4.5 and 25 C. These are the first multicomponent diffusion coefficients measured for any protein system at concentrations high enough to be relevant to modeling and prediction of crystal growth or other phase transitions, and the first for a system involving lysozyme at any concentration. The four ternary diffusion coefficients for the system lysozyme chloride/NaCl/water are reported for lysozyme chloride at 0.60 mM (8.6 mg/mL) and NaCl at concentrations of 0.25, 0.50, 0.65, 0.90, and 1.30 M (1.4, 2.8, 3.7, 5.1, and 7.2 wt %), with the latter two compositions being supersaturated. One cross-term, (D{sub 21}){sub v}, is 80--259 times larger than the main term (D{sub 11}){sub v} and 7--18 times larger than (D{sub 22}){sub v}. Standard interferometric diagnostic tests indicate that aggregation is unimportant in the experiments. The authors also present binary diffusion coefficients D{sub v} for lysozyme chloride/water at concentrations from 0.43 to 3.08 mM (6.2--44.1 mg/mL), at the same pH and temperature. The precision of the results is about 0.1% for the binary diffusion coefficients and diagonal ternary diffusion coefficients, and about 1--2% for the cross-terms. For the ternary systems investigated, they show that a single pseudobinary diffusion coefficient does not accurately describe diffusive transport, and predictions by simple models such as the Nernst-Hartley equations are inaccurate at the higher concentrations considered here. Finally, dynamic light-scattering diffusion coefficients, differing form both the interferometrically measured (D{sub ij}){sub v} and a theoretical prediction of light-scattering diffusion coefficients in multicomponent systems, are reported for the same solutions used for the ternary experiments at 1.30 M.

Albright, J.G.; Annunziata, O. [Texas Christian Univ., Fort Worth, TX (United States). Chemistry Dept.] [Texas Christian Univ., Fort Worth, TX (United States). Chemistry Dept.; Miller, D.G. [Texas Christian Univ., Fort Worth, TX (United States). Chemistry Dept.] [Texas Christian Univ., Fort Worth, TX (United States). Chemistry Dept.; [Lawrence Livermore National Lab., CA (United States); Paduano, L. [Texas Christian Univ., Fort Worth, TX (United States). Chemistry Dept.] [Texas Christian Univ., Fort Worth, TX (United States). Chemistry Dept.; [Univ. di Napoli, Naples (Italy). Dipt. di Chimica; Pearlstein, A.J. [Univ. of Illinois, Urbana, IL (United States). Dept. of Mechanical and Industrial Engineering] [Univ. of Illinois, Urbana, IL (United States). Dept. of Mechanical and Industrial Engineering

1999-04-14T23:59:59.000Z

362

Determination of laser damage initiation probability and growth on fused silica scratches  

SciTech Connect

Current methods for the manufacture of optical components inevitably leaves a variety of sub-surface imperfections including scratches of varying lengths and widths on even the finest finishes. It has recently been determined that these finishing imperfections are responsible for the majority of laser-induced damage for fluences typically used in ICF class lasers. We have developed methods of engineering subscale parts with a distribution of scratches mimicking those found on full scale fused silica parts. This much higher density of scratches provides a platform to measure low damage initiation probabilities sufficient to describe damage on large scale optics. In this work, damage probability per unit scratch length was characterized as a function of initial scratch width and post fabrication processing including acid-based etch mitigation processes. The susceptibility of damage initiation density along scratches was found to be strongly affected by the post etching material removal and initial scratch width. We have developed an automated processing procedure to document the damage initiations per width and per length of theses scratches. We show here how these tools can be employed to provide predictions of the performance of full size optics in laser systems operating at 351 nm. In addition we use these tools to measure the growth rate of a damage site initiated along a scratch and compare this to the growth measured on an isolated damage site.

Norton, M A; Carr, C W; Cross, D A; Negres, R A; Bude, J D; Steele, W A; Monticelli, M V; Suratwala, T I

2010-10-26T23:59:59.000Z

363

Damage and ablation thresholds of fused-silica in femtosecond regime  

SciTech Connect

We present an experimental and numerical study of the damage and ablation thresholds at the surface of a dielectric material, e.g., fused silica, using short pulses ranging from 7 to 300 fs. The relevant numerical criteria of damage and ablation thresholds are proposed consistently with experimental observations of the laser irradiated zone. These criteria are based on lattice thermal melting and electronic cohesion temperature, respectively. The importance of the three major absorption channels (multi-photon absorption, tunnel effect, and impact ionization) is investigated as a function of pulse duration (7-300 fs). Although the relative importance of the impact ionization process increases with the pulse duration, our results show that it plays a role even at short pulse duration (<50 fs). For few optical cycle pulses (7 fs), it is also shown that both damage and ablation fluence thresholds tend to coincide due to the sharp increase of the free electron density. This electron-driven ablation regime is of primary interest for thermal-free laser-matter interaction and therefore for the development of high quality micromachining processes.

Chimier, B.; Uteza, O.; Sanner, N.; Sentis, M. [Laboratoire LP3, UMR 6182 CNRS - Universite de la Mediterranee, C. 917, 163, Av. de Luminy, 13288 Marseille cedex 9 (France); Itina, T. [Laboratoire Hubert Curien - LaHC, UMR 5516 CNRS - Universite Jean Monnet, Bat. F, 18, rue Professeur B. Lauras, 42000 Saint-Etienne (France); Lassonde, P.; Legare, F.; Vidal, F.; Kieffer, J. C. [INRS, Energie, Materiaux et Telecommunications, 1650 bld Lionel Boulet, Varennes (Quebec), J3X 1S2 (Canada)

2011-09-01T23:59:59.000Z

364

Molecular dynamics simulation of elevated temperature interfacial behavior between silica glass and a model crystal  

SciTech Connect

Elevated temperature atomistic behavior was investigated using classical molecular dynamics simulations of solid state interfaces. Initially, observations on a Lennard-Jones (LJ) crystal surface interfaced with an ideal vacuum were made. Assignment of temperatures associated with specific amounts of crystal surface disorder was possible. A temperature was observed at and above which disorder propagated through all planes of mobile atoms, making it possible to establish an approximate transition temperature for surface nucleated melting of the LJ crystal. Similar high temperature simulations were then performed on silica glass/LJ crystal interfaces at two system stress levels. No significant dependence of interface behavior on the stress states which were studied was observed. The presence of the glass surface resulted in a depression of the temperature needed for the surface most planes of crystal atoms to roughen. This allowed LJ atoms to sample and occupy sites in the glass surface. Additional data presented shows this behavior was at least partly a function of the open structure inherent in glassy oxide surfaces. {copyright} {ital 1996 American Institute of Physics.}

Webb, E.B. III; Garofalini, S.H. [Department of Ceramics, Interfacial Molecular Science Laboratory, Rutgers University, Piscataway, New Jersey 08855 (United States)] [Department of Ceramics, Interfacial Molecular Science Laboratory, Rutgers University, Piscataway, New Jersey 08855 (United States)

1996-07-01T23:59:59.000Z

365

Transient heat transfer characteristic of silica aerogel insulating material considering its endothermic reaction  

Science Journals Connector (OSTI)

Abstract In the current work, we present an experimental study to investigate the reaction mechanism of silica aerogel material at high temperature. The experimental study is based on simultaneous thermal analyzer 449F3 as well as Fourier Transform Infrared Spectroscopy (FTIR). The results show that when the material is exposed at high temperature, the mass of material will decrease about 1.98% accompanying with endothermic effect. Via FTIR analysis, it is found that the mass loss of material may be caused by the removal of adsorbed water. Besides the experimental study, a numerical heat transfer model is constructed to study the transient heat transfer characteristic of aerogel material by taking the endothermic reaction into account. The numerical heat transfer model is validated by a classical Stefan problem and a corresponding experimental measurement. Afterwards, a parametric study is conducted to investigate the effect of two parameters, reaction temperature and reaction heat, on transient heat transfer characteristics of aerogel insulating material. The results show that: (1) Before reaching the reaction temperature Treaction, the material that with lower Treaction possesses lower temperature. However, when it exceeds the reaction temperature, the material shows the highest temperature among other materials. (2) With the increase of reaction heat, the increasing trend of temperature is weakened and the emergent of the turning point that separates the temperature platform and temperature-rise period appears later.

Tao Xie; Ya-Ling He; Zi-Xiang Tong; Wei-Xu Yan; Xiang-Qian Xie

2014-01-01T23:59:59.000Z

366

Adsorption and methanation of carbon dioxide on a nickel/silica catalyst  

SciTech Connect

The adsorption and methanation of carbon dioxide on a nickel/silica catalyst were studied using temperature-programmed desorption and temperature-programmed reaction. Carbon dioxide adsorption on nickel was found to be activated; almost no adsorption occurred at room temperature, but large coverages were obtained between 383 and 473 K. The data indicate CO/sub 2/ dissociates upon adsorption at elevated temperatures to yield carbon monoxide and oxygen atoms. These oxygen atoms react with hydrogen at room temperature, so the methane and water observed during programmed heating in flowing hydrogen are identical for adsorbed CO and adsorbed CO/sub 2/. Single CH/sub 4/ and H/sub 2/O peaks, each with a peak temperature at 473 K, were observed. This peak temperature did not change with initial coverage, indicating methanation is first order in CO surface coverage. The activated adsorption of CO/sub 2/ allowed these coverage variation experiments to be carried out. Thus, following adsorption, CO and CO/sub 2/ methanation proceed by the same mechanism. However, the activated adsorption of CO/sub 2/ may create a higher H/sub 2/:CO surface ratio during steady-state hydrogenation, causing CO/sub 2/ hydrogenation to favor methane over higher hydrocarbons. 5 figures.

Falconer, J.L.; Zagli, A.E.

1980-04-01T23:59:59.000Z

367

Inhibition of total oxygen uptake by silica nanoparticles in activated sludge  

Science Journals Connector (OSTI)

Abstract Nanoparticle toxicity to biological activities in activated sludge is largely unknown. Among the widely used nanoparticles, silica nanoparticles (SNP) have a limited number of studies associated with inhibition to the activated sludge process (ASP). We demonstrated SNP inhibition of activated sludge respiration through oxygen uptake rate (OUR) measurement. Based on the percentage inhibition of total oxygen consumption (IT), we observed that smaller \\{SNPs\\} (12nm, IT=333%; 151nm, IT=232%) were stronger inhibitors than larger \\{SNPs\\} (442 and 683nm, IT=51%). Transmission electron micrographs showed that some of the \\{SNPs\\} were adsorbed on and/or apparently embedded somewhere in the microbial cell membrane. Whether \\{SNPs\\} are directly associated with the inhibition of total oxygen uptake warrants further studies. However, it is clear that \\{SNPs\\} statistically significantly altered the composition of microbial membrane lipids, which was more clearly described by principal component analysis and weighted Euclidian distance (PCA-ED) of the fatty acid methyl ester (FAME) data. This study suggests that \\{SNPs\\} potentially affect the biological activity in activated sludge through the inhibition of total oxygen uptake.

Mark Sibag; Byeong-Gyu Choi; Changwon Suh; Kwan Hyung Lee; Jae Woo Lee; Sung Kyu Maeng; Jinwoo Cho

2015-01-01T23:59:59.000Z

368

Solar powered heat pump construction. [silica gel adsorbent with solar regenerator  

SciTech Connect

Disclosed is a solar powered heat pump useful for both heating and cooling building space and for providing refrigeration. The device operates on a chemical effect (Adsorption) intermittent heat pump cycle in which the moderately high temperature heat generated by insolation is used to drive the desorber. The device has inherent thermal storage, can be factory built, sealed, and tested, can be electronically controlled for completely automatic operation, and includes a built-in back-up heater which obviates the need for installation of a separate back-up heating system. It can be manufactured from inexpensive materials such as glass, and implodes rather than explodes on failure. A preferred embodiment of the device is designed as a modular unit which can readily be combined with others of identical design to produce a solar powered battery panel for heating and cooling. This embodiment preferably comprises a tubular enclosure defining a pair of chambers separated by a valve. A first chamber is packed with silica gel (Or an equivalent adsorbent material) arranged such that mass and heat transfer through the gel take place rapidly and in comparable time periods. The first chamber is surrounded by a larger diameter, solar radiation transparent housing and the annular space between the chamber and housing is evacuated. The enclosure is mounted together with a diffuse light reflector which focuses sunlight toward the first chamber. Heat exchangers provide thermal communication between respective chambers and a pair of duct portions adapted for connection to a building heat distribution system.

Berg, C.A.

1980-11-04T23:59:59.000Z

369

Rapid Extraction of Dust Impact Tracks from Silica Aerogel by Ultrasonic Micro-blades  

SciTech Connect

In January 2006, NASA's Stardust Mission will return with its valuable cargo of cometary dust particles, the first brought back to Earth, captured at hypervelocity speeds in silica aerogel collectors. Aerogel, a proven capture medium, is also a candidate for future sample return missions and low-earth orbit (LEO) deployments. Critical to the science return of Stardust and future missions using aerogel is the ability to efficiently extract impacted particles from collector tiles. Researchers will be eager to obtain Stardust samples as quickly as possible, and tools for the rapid extraction of particle impact tracks that require little construction, training, or investment would be an attractive asset. To this end, we have experimented with diamond and steel micro-blades. Applying ultrasonic frequency oscillations to these micro-blades via a piezo-driven holder produces rapid, clean cuts in the aerogel with minimal damage to the surrounding collector tile. With this approach, impact tracks in aerogel fragments with low-roughness cut surfaces have been extracted from aerogel tiles flown on NASA's Orbital Debris Collector Experiment. The smooth surfaces produced during cutting reduce imaging artifacts during analysis by SEM. Some tracks have been dissected to expose the main cavity for eventual isolation of individual impact debris particles and further analysis by techniques such as TEM and nanoSIMS.

Ishii, H; Graham, G; Kearsley, A T; Grant, P G; Snead, C J; Bradley, J P

2005-02-17T23:59:59.000Z

370

MULTICOMPONENT SEISMIC ANALYSIS AND CALIBRATION TO IMPROVE RECOVERY FROM ALGAL MOUNDS: APPLICATION TO THE ROADRUNNER/TOWAOC AREA OF THE PARADOX BASIN, UTE MOUNTAIN UTE RESERVATION, COLORADO  

SciTech Connect

This report describes the results made in fulfillment of contract DE-FG26-02NT15451, ''Multicomponent Seismic Analysis and Calibration to Improve Recovery from Algal Mounds: Application to the Roadrunner/Towaoc Area of the Paradox Basin, Ute Mountain Ute Reservation, Colorado''. Optimizing development of highly heterogeneous reservoirs where porosity and permeability vary in unpredictable ways due to facies variations can be challenging. An important example of this is in the algal mounds of the Lower and Upper Ismay reservoirs of the Paradox Basin in Utah and Colorado. It is nearly impossible to develop a forward predictive model to delineate regions of better reservoir development, and so enhanced recovery processes must be selected and designed based upon data that can quantitatively or qualitatively distinguish regions of good or bad reservoir permeability and porosity between existing well control. Recent advances in seismic acquisition and processing offer new ways to see smaller features with more confidence, and to characterize the internal structure of reservoirs such as algal mounds. However, these methods have not been tested. This project will acquire cutting edge, three-dimensional, nine-component (3D9C) seismic data and utilize recently-developed processing algorithms, including the mapping of azimuthal velocity changes in amplitude variation with offset, to extract attributes that relate to variations in reservoir permeability and porosity. In order to apply advanced seismic methods a detailed reservoir study is needed to calibrate the seismic data to reservoir permeability, porosity and lithofacies. This will be done by developing a petrological and geological characterization of the mounds from well data; acquiring and processing the 3D9C data; and comparing the two using advanced pattern recognition tools such as neural nets. In addition, should the correlation prove successful, the resulting data will be evaluated from the perspective of selecting alternative enhanced recovery processes, and their possible implementation. The work is being carried out on the Roadrunner/Towaoc Fields of the Ute Mountain Ute Tribe, located in the southwestern corner of Colorado. Although this project is focused on development of existing resources, the calibration established between the reservoir properties and the 3D9C seismic data can also enhance exploration success. During the time period covered by this report, the majority of the project effort has gone into the permitting, planning and design of the 3D seismic survey, and to select a well for the VSP acquisition. The business decision in October, 2002 by WesternGeco, the projects' seismic acquisition contractor, to leave North America, has delayed the acquisition until late summer, 2003. The project has contracted Solid State, a division of Grant Geophysical, to carry out the acquisition. Moreover, the survey has been upgraded to a 3D9C from the originally planned 3D3C survey, which should provide even greater resolution of mounds and internal mound structure.

Paul La Pointe; Claudia Rebne; Steve Dobbs

2003-07-10T23:59:59.000Z

371

Origin of improved scintillation efficiency in (Lu,Gd){sub 3}(Ga,Al){sub 5}O{sub 12}:Ce multicomponent garnets: An X-ray absorption near edge spectroscopy study  

SciTech Connect

In the recent successful improvement of scintillation efficiency in Lu{sub 3}Al{sub 5}O{sub 12}:Ce driven by Ga{sup 3+} and Gd{sup 3+} admixture, the band-gap engineering and energy level positioning have been considered the valid strategies so far. This study revealed that this improvement was also associated with the cerium valence instability along with the changes of chemical composition. By utilizing X-ray absorption near edge spectroscopy technique, tuning the Ce{sup 3+}/Ce{sup 4+} ratio by Ga{sup 3+} admixture was evidenced, while it was kept nearly stable with the Gd{sup 3+} admixture. Ce valence instability and Ce{sup 3+}/Ce{sup 4+} ratio in multicomponent garnets can be driven by the energy separation between 4f ground state of Ce{sup 3+} and Fermi level.

Wu, Yuntao, E-mail: caswyt@hotmail.com; Luo, Jialiang; Ren, Guohao [Shanghai Institute of Ceramics, Chinese Academy of Sciences, No.215 Road, Jiading, Shanghai 201899 (China); Nikl, Martin [Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnick 10, 16253 Prague 6 (Czech Republic)

2014-01-01T23:59:59.000Z

372

Intraparticle heat and mass transfer characteristics of silica-gel/water vapor adsorption  

SciTech Connect

Recently, highly efficient energy utilization systems which extensively employ adsorption phenomena such as pressure swing adsorption, heat storage, adsorption heat pump, etc. are being regarded as one of the countermeasures for environmental issues such as green house effect and ozone layer destruction. An Adsorption Heat Pump (AHP) has been investigated as one of the important techniques via which cold heat energy is obtained from waste thermal energy below 373K without using electricity and CFCs. An AHP normally consists of an adsorber and an evaporator/condenser and cold heat energy is generated by latent heat of evaporation during adsorption process. For realizing the AHP technology, it has been pointed out that the development of an adsorber with optimum heat and mass transfer characteristics is essentially important. In this study, experimental studies were carried out which was based on the data of temperature inside the adsorbent particle and adsorptivity profiles at the adsorption/desorption process by volumetric method. To clarify adsorption mechanism relatively large silica-gel particle (7 mm f) was used. Temperature distribution in the particle is determined at the center, at one half radius in the radial direction and at the surface by using very thin (30 mm f) thermocouples. The temperatures at these points simultaneously increase/decrease as soon as the adsorption/desorption started, reached their respective maximum/minimum values and then return to initial temperature. The temperature profiles for the adsorption process show that the temperature at the surface is initially slightly higher than the other two points. All three points reached their respective maximum temperature at the same time with the temperature at the center point the highest and at the surface the lowest. The temperature profiles during the desorptive process are almost exactly the opposite to that of the adsorption process. This shows that the adsorption phenomena can take place not only at the surface but inside the adsorbent particle, implying that intraparticle vapor diffusion has a great influence on adsorptivity.

Yamamoto, Eri; Watanabe, Fujio; Hasatani, Masanobu

1999-07-01T23:59:59.000Z

373

Thermal conductivity studies of novel nanofluids based on metallic silver decorated mesoporous silica nanoparticles  

SciTech Connect

Graphical abstract: - Highlights: Metallic silver was decorated in mSiO{sub 2} with grafted hemiaminal functional groups. Synthesized nanoparticles were used for preparation of glycerol based nanofluids. The effect of temperature, weight fraction of mSiO{sub 2} and concentration of silver nanoparticles on thermal conductivity of nanofluids was investigated. - Abstract: In the present study, the mesoporous structure of silica (mSiO{sub 2}) nanoparticles as well as hemiaminal grafted mSiO{sub 2} decorated by metallic silver (Ag/mSiO{sub 2}) has been used for the preparation of glycerol based nanofluids. Structural and morphological characterization of the synthesized products have been carried out using Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), X-ray diffraction (XRD), UVvis spectroscopy, inductively coupled plasma (ICP) and N{sub 2} adsorptiondesorption isotherms. The thermal conductivity and viscosity of the nanofluids have been measured as a function of temperature for various weight fractions and silver concentrations of mSiO{sub 2} and Ag/mSiO{sub 2} nanoparticles, respectively. The results show that the thermal conductivity of the nanofluids increase up to 9.24% as the weight fraction of mSiO{sub 2} increases up to 4 wt%. Also, increasing the percent of the silver decorated mSiO{sub 2} (Ag/mSiO{sub 2}) up to 2.98% caused an enhancement in the thermal conductivity of the base fluid up to 10.95%. Furthermore, the results show that the nanofluids have Newtonian behavior in the tested temperature range for various concentrations of nanoparticles.

Tadjarodi, Azadeh, E-mail: tajarodi@iust.ac.ir [Research Laboratory of Inorganic Materials Synthesis, Department of Chemistry, Iran University of Science and Technology, 16846-13114 Tehran (Iran, Islamic Republic of); Zabihi, Fatemeh [Research Laboratory of Inorganic Materials Synthesis, Department of Chemistry, Iran University of Science and Technology, 16846-13114 Tehran (Iran, Islamic Republic of); Chemistry and Nanotechnology Laboratory, National Center for Laser Science and Technology, Tehran (Iran, Islamic Republic of)

2013-10-15T23:59:59.000Z

374

Electron paramagnetic resonance study of paramagnetic centers in carbon-fumed silica adsorbent  

SciTech Connect

Fumed silica A-300 was carbonized by means of pyrolysis of CH{sub 2}Cl{sub 2}. The obtained initial SiO{sub 2}:C nanopowders of black color, with an average diameter of 1416?nm and carbon (C) concentration 7?wt. %, subjected to the oxidation and passivation treatment were studied by electron paramagnetic resonance (EPR) in the temperature range 4400?K. Two EPR signals of Lorentzian lineshape with nearly equal g-factors and different linewidth were observed in the initial, oxidized, and passivated SiO{sub 2}:C nanopowders. The two-component EPR spectrum was explained by the presence of C in two electronic states. The intensive narrow EPR signal, which has a temperature-dependent intensity, linewidth, and resonance field position, was attributed to the carbon-related defect with non-localized electron hopping between neighboring C-dangling bonds. The striking effect is that the temperature dependence of the EPR linewidth demonstrates the motional narrowing of the EPR signal at very low temperatures from 4?K to 20?K, which is not typically for nonmetallic materials and was explained by the quantum character of C layer conductivity in the SiO{sub 2}:C. The observed peaks in the temperature dependence of the conduction electron EPR signal integral intensity in the high-temperature range 200440?K was explained by the presence of the C nanodots at the surface of SiO{sub 2} nanoparticles and the ejection of electrons from the confinement energy levels of C quantum dot when the temperature becomes comparable to the confinement energy.

Savchenko, D. V., E-mail: dariyasavchenko@gmail.com [Institute of Physics AS CR, Prague 182 21 (Czech Republic); V.E. Lashkaryov Institute of Semiconductor Physics, NASU, Kyiv 03028 (Ukraine); Shanina, B. D.; Kalabukhova, E. N.; Sitnikov, A. A.; Lysenko, V. S. [V.E. Lashkaryov Institute of Semiconductor Physics, NASU, Kyiv 03028 (Ukraine); Tertykh, V. A. [A.A. Chuiko Institute of Surface Chemistry, NASU, Kyiv 03164 (Ukraine)

2014-04-07T23:59:59.000Z

375

Imaging the early material response associated with exit surface damage in fused silica  

SciTech Connect

The processes involved at the onset of damage initiation on the surface of fused silica have been a topic of extensive discussion and thought for more than four decades. Limited experimental results have helped develop models covering specific aspects of the process. In this work we present the results of an experimental study aiming at imaging the material response from the onset of the observation of material modification during exposure to the laser pulse through the time point at which material ejection begins. The system involves damage initiation using a 355 nm pulse, 7.8 ns FWHM in duration and imaging of the affected material volume with spatial resolution on the order of 1 {micro}m using as strobe light a 150 ps laser pulse that is appropriately timed with respect to the pump pulse. The observations reveal that the onset of material modification is associated with regions of increased absorption, i.e., formation of an electronic excitation, leading to a reduction in the probe transmission to only a few percent within a time interval of about 1 ns. This area is subsequently rapidly expanding with a speed of about 1.2 {micro}m/ns and is accompanied by the formation and propagation of radial cracks. These cracks appear to initiate about 2 ns after the start of the expansion of the modified region. The damage sites continue to grow for about 25 ns but the mechanism of expansion after the termination of the laser pulse is via formation and propagation of lateral cracks. During this time, the affected area of the surface appears to expand forming a bulge of about 40 {micro}m in height. The first clear observation of material cluster ejection is noted at about 50 ns delay.

Demos, S G; Raman, R N; Negres, R A

2010-11-05T23:59:59.000Z

376

Residual stress and damage-induced critical fracture on CO2 laser treated fused silica  

SciTech Connect

Localized damage repair and polishing of silica-based optics using mid- and far-IR CO{sub 2} lasers has been shown to be an effective method for increasing optical damage threshold in the UV. However, it is known that CO{sub 2} laser heating of silicate surfaces can lead to a level of residual stress capable of causing critical fracture either during or after laser treatment. Sufficient control of the surface temperature as a function of time and position is therefore required to limit this residual stress to an acceptable level to avoid critical fracture. In this work they present the results of 351 nm, 3 ns Gaussian damage growth experiments within regions of varying residual stress caused by prior CO{sub 2} laser exposures. Thermally stressed regions were non-destructively characterized using polarimetry and confocal Raman microscopy to measure the stress induced birefringence and fictive temperature respectively. For 1 {approx} 40s square pulse CO{sub 2} laser exposures created over 0.5-1.25 kW/cm{sup 2} with a 1-3 mm 1/e{sup 2} diameter beam (T{sub max} {approx} 1500-3000 K), the critical damage site size leading to fracture increases weakly with peak temperature, but shows a stronger dependence on cooling rate, as predicted by finite element hydrodynamics simulations. Confocal micro-Raman was used to probe structural changes to the glass over different thermal histories and indicated a maximum fictive temperature of 1900K for T{sub max} {ge} 2000 K. The effect of cooling rate on fictive temperature caused by CO{sub 2} laser heating are consistent with finite element calculations based on a Tool-Narayanaswamy relaxation model.

Matthews, M; Stolken, J; Vignes, R; Norton, M

2009-11-02T23:59:59.000Z

377

Recent progress in the development of large area silica aerogel for use as RICH radiator in the Belle II experiment  

E-Print Network (OSTI)

We report recent progress in the development of large-area hydrophobic silica aerogels for use as radiators in the aerogel-based ring-imaging Cherenkov (A-RICH) counter to be installed in the forward end cap of the Belle II detector, which is currently being upgraded at the High Energy Accelerator Research Organization (KEK), Japan. The production of approximately 450 aerogel tiles with refractive indices of either 1.045 or 1.055 was completed in May, 2014, and the tiles are now undergoing optical characterization. Installation of the aerogels was tested by installing them into a partial mock-up of the support structure.

Makoto Tabata; Ichiro Adachi; Hideyuki Kawai; Shohei Nishida; Takayuki Sumiyoshi

2014-11-16T23:59:59.000Z

378

Recent progress in the development of large area silica aerogel for use as RICH radiator in the Belle II experiment  

E-Print Network (OSTI)

We report recent progress in the development of large-area hydrophobic silica aerogels for use as radiators in the aerogel-based ring-imaging Cherenkov (A-RICH) counter to be installed in the forward end cap of the Belle II detector, which is currently being upgraded at the High Energy Accelerator Research Organization (KEK), Japan. The production of approximately 450 aerogel tiles with refractive indices of either 1.045 or 1.055 was completed in May, 2014, and the tiles are now undergoing optical characterization. Installation of the aerogels was tested by installing them into a partial mock-up of the support structure.

Tabata, Makoto; Kawai, Hideyuki; Nishida, Shohei; Sumiyoshi, Takayuki

2014-01-01T23:59:59.000Z

379

Silica gel as a model surface for adsorption calorimetry of enhanced-oil-recovery systems. [Heat of immersion  

SciTech Connect

This report describes a method for studying interaction of fluids with surfaces by measuring the heat of immersion and then measuring simultaneously the surface excess and enthalpy of replacement for a series of binary solutions. The method of calculating surface excess is described. These techniques are applied to silica gel which has had different activation temperatures. Heating overnight to 400/sup 0/C results in a reproducible surface. The adsorption of n-butyl alcohol from toluene and from water upon these surfaces is compared.

Noll, L.A.; Burchfield, T.E.

1982-06-01T23:59:59.000Z

380

Effect of dilution and contaminants on strength and hydraulic conductivity of sand grouted with colloidal silica gel  

SciTech Connect

Colloidal silica (CS) is a low-viscosity liquid that can be made to gel by addition of brine. This property allows it to be injected into, or mixed with, soil, so that after gelling the colloidal silica blocks the pore space in the soil and forms a barrier to the flow of contaminated groundwater or non-aqueous liquids (NAPLs). Gelled-in-place CS was first studied for the petroleum industry and later for protecting groundwater quality. Noll investigated the use of colloidal silica diluted so that its solids content was reduced from 30% (a typical nominal value for material as delivered) to values as low as 5%. The more dilute colloids could still be made to gel, although more slowly, and the resulting gel was weaker. Because the proposed application of colloidal silica grout involves emplacing it in the subsurface by permeation, jet grouting, or soil mixing where its role as a barrier will be to resist flow of contaminants, the effects of these contaminants on the properties of the grouted soil is also of interest. This work comprised four tasks. In Task 1, samples of grouted sand were prepared with a range of CS dilutions, for measurement of hydraulic conductivity and unconfined-compressive strength. In Task 2, these properties were measured on samples of grouted sand that incorporated 5% volumetric saturation of NAPLs. In Task 3, samples, prepared without any contaminants, were immersed in contaminant liquids and tested after 30 and 90 days. Task 4 was added because NAPL contamination in the samples of Tasks 2 and 3 impelled modifications in the test methods, and comparison of the results of Task 2 and Task 1 suggested that these modifications had introduced errors. In Task 4, samples were tested both ways, to confirm that in Tasks 2 and 3 strength was underestimated and hydraulic conductivity was overestimated. Despite the existence of these known systematic errors, the inclusion of control samples in Tasks 2 and 3 permits conclusions to be drawn from these data.

Persoff, P.; Apps, J.A.; Moridis, G.J. [and others

1996-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "multicomponent geothermometers silica" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Field Trip Guide to Serpentinite, Silica-Carbonate Alteration, and Related Hydrothermal Activity in the Clear Lake Region, California  

SciTech Connect

This guide is designed to familiarize scientists with the geology, structure, alteration, and fluids typical of California serpentinites for purposes of carbon dioxide sequestration (Lackner et al., 1995). Goff et al. (1997) and Goff and Lackner (1998) describe the geology and geochemistry of some of the serpentinites from this area. Mechanisms of silica-carbonate alteration were outlined by Barnes et al. (1973). Donnelly-Nolan et al. (1993) most recently reviewed relations between regional hydrothermal alteration and Quarternary volcanic activity. Stanley et al. (1998) summarized geophysical characteristics of the region.

Fraser Goff; George Guthrie

1999-06-01T23:59:59.000Z

382

A STUDY OF FISCHER 344 RATS EXPOSED TO SILICA DUST FOR SIX MONTHS AT CONCENTRATIONS OF 0, 2, 10 OR 20 MG / M3.  

SciTech Connect

The major objective of this study was to relate the results of a series of functional tests to the compositional and structural alterations in the rat lung induced by subchronic exposure to silica dust. Fischer-344 rats were exposed for 6 hours/day, 5 days/week for 6 months to either 0, 2, 10, or 20 mg SiO{sub 2}/m{sup 3}. The general appearance of the exposed rats was not different from that of the controls. Interestingly, female rats exposed to silica dust, at all tested concentrations, gained more weight than the controls. The lung weight and the lung-to-body weight ratio was greater in the male rats exposed to the highest concentration of silica dust.

KUTZMAN,R.S.

1984-02-01T23:59:59.000Z

383

Crystallization of fused silica surfaces by ultra-violet laser irradiation  

SciTech Connect

In recent years, the increased use of high power lasers has created problems in optical elements due to laser damage. The International Organization for Standardization (ISO) describes in a publication ISO 11254 a laser-power resilience (LPR) test which we used to verify that by flattening the glass substrate of an optical element, we could improve the resistance to laser damage. We report on an evaluation of two types of samples of fused silica substrate whose surface roughness differed (R{sub a} = 0.20 nm and R{sub a} = 0.13 nm) using customized on-line laser damage testing. To induce laser damage to samples, we used the fifth harmonic generation from a Nd:YAG pulse laser (wavelength: 213 nm, pulse width: 4 ns, repetition frequency: 20 Hz). Results show that flattening reduced the progression of laser damage in the meta-phase laser damage phase by 1/3 of that without flattening. However, pro-phase laser damage which started at fluence 2.39 J/cm{sup 2} was unrelated to surface roughness. To analyze the pro-phase laser damage, we used x-ray diffraction (XRD), Raman spectroscopy, and variable pressure-type scanning electron microscopy (VP-SEM). From XRD data, we observed XRD patterns of cristobalite (111), cristobalite (102), {alpha}-quartz (111), and {beta}-quartz (102). Raman spectrum data showed an increase in the three-membered ring vibration (600 cm{sup -1}), four-membered ring vibration (490 cm{sup -1}), and many-membered ring vibration (450 cm{sup -1}, 390 cm{sup -1}, and 300 cm{sup -1}). We observed patchy crystallized areas on the sample surfaces in the VP-SEM images. Based on these experimental results, we believe that the dominant factors in pro-phase laser damage are their physical properties. Substrate and thin film material must be appropriately selected in producing an optical element with a high level of resilience to laser exposure.

Hirata, Kazuya; Haraguchi, Koshi [Sigma Koki Co., Ltd., 1-19-9 Midori, Sumida-ku, Tokyo 130-0021 (Japan)

2012-07-15T23:59:59.000Z

384

NEAR-IR TWO PHOTON MICROSCOPY IMAGING OF SILICA NANOPARTICLES FUNCTIONALIZED WITH ISOLATED SENSITIZED Yb(III) CENTERS  

SciTech Connect

Bright nano objects emitting in the near infrared with a maximal cross section of 41.4 x 103 GM (Goppert Mayer), were prepared by implanting ca. 180 4,4 diethylaminostyryl 2,2 bipyridine (DEAS) Yb(III) complexes on the surface of 12 nm silica nanoparticles. The surface complexes ([DEAS Ln SiO2], Ln =Y,Yb) were characterized using IR, solid state NMR, UV Vis, EXAFS spectroscopies in combination with the preparation and characterization of similar molecular analogues by analytical techniques (IR, solution NMR, UV Vis, X ray crystallography) as well as DFT calculations. Starting from the partial dehydroxylation of the silica at 700 C on high vacuum having 0.8 OH.nm 2, the grafting of Ln(N(SiMe3)2)3 generate ?SiO Ln(N(SiMe3)2)2, which upon thermal step and coordination of the DEAS chromophore yields (?SiO)3Ln(DEAS). Surface and molecular analogues display similar properties, in terms of DEAS binding constants absorption maxima and luminescence properties (intense emission band assigned to a ligand centered CT fluorescence and life time) in the solid state, consistent with the molecular nature of the surface species. The densely functionalized nanoparticles can be dispersed via ultra-sonication in small ca. 15-20 nm aggregates (1 to 6 elementary particles) that were detected using two photon microscopy imaging at 720 nm excitation, making them promising nano objects for bio imaging.

Lapadula, Giuseppe; Bourdolle, Adrien; Allouche, Florian; Conley, Matthew P.; Maron, Laurent; Lukens, Wayne W.; Guyot, Yannick; Andraud, Chantal; Brasselet, Sophie; Cop; ret, Christophe; Maury, Olivier; Andersen, Richard A.

2013-01-12T23:59:59.000Z

385

Experimental and analytical analyses of the thermal conductivities and high-temperature characteristics of silica aerogels based on microstructures  

Science Journals Connector (OSTI)

An analytical heat transfer model based on scanning electron microscopy, BrunauerEmmettTeller and pycnometry measurements and a 3D random diffusion-limited clustercluster aggregation structure is proposed to calculate the temperature-dependent microstructural parameters and thermal conductivities of silica aerogels. This model is a pure prediction model, which does not need experimentally fitted empirical parameters and only needs four measured structural parameters as input parameters. This model can provide high-temperature microstructural and thermophysical properties as well as theoretical guidelines for material designs with optimum parameters. The results show that three stages occur during the thermal evolution processes of the aerogel structure with increasing temperature from 300 to 1500K. The current analytical model is fully validated by experimental data. The constant structure assumptions used in previous heat transfer models are found to cause significant errors at higher temperatures as the temperature-dependent structure deformation significantly increases the aerogel thermal conductivity. The conductive and total thermal conductivities of silica aerogels after high-temperature heat treatments are much larger than those with no heat treatment.

Jun-Jie Zhao; Yuan-Yuan Duan; Xiao-Dong Wang; Bu-Xuan Wang

2013-01-01T23:59:59.000Z

386

Comprehensive Study of the Impact of Steam on Polyethyleneimine on Silica for CO{sub 2} Capture  

SciTech Connect

An amine sorbent, prepared by impregnation of polyethyleneimine on silica, was tested for steam stability. The stability of the sorbent was investigated in a fixed bed reactor using multiple steam cycles of 90 vol.% H{sub 2}O/He at 105 {degrees}?C and the gas effluent was monitored with a mass spectrometer. CO{sub 2} uptake of sorbent was found to decrease with repeated exposure to steam. Characterization of the spent sorbent using N{sub 2} physisorption, SEM, and thermogravimetric analysis (TGA), showed that the decrease in CO{sub 2} loading can possibly be attributed to a reagglomeration of the amine in the pores of the silica. No support effect was found in this study. The commercial SiO{sub 2} used, Cariact G10, was found to be stable under the conditions used. While it was found that subjecting the sorbent to several steam cycles decreased its CO{sub 2} uptake, a continuous exposure of the sorbent to steam did not have a significant performance impact. A silanated sorbent, consisting of a mixture of PEI and aminopropyl-triethoxysilane on SiO{sub 2} support, was also investigated for steam stability. Similarly to the non-silanated sorbent, the CO{sub 2} loading of this sorbent decreased upon steam exposure, although a mechanism for this change has not been postulated at this time.

Hammache, Sonia; Hoffman, James S.; Gray, McMahan L.; Fauth, Daniel J; Howard, Bret H.; Pennline, Henry W.

2013-11-01T23:59:59.000Z

387

Nanoporous Polytetrafluoroethylene/Silica Composite Separator as a High-Performance All-Vanadium Redox Flow Battery Membrane  

SciTech Connect

Driven by the motivation of searching for low-cost membrane alternatives, a novel nanoporous polytetrafluoroethylene/silica composite separator has been prepared and evaluated for its use in all-vanadium mixed-acid redox flow battery. This separator consisting of silica particles enmeshed in a polytetrafluoroethylene fibril matrix has no ion exchange capacity and is featured with unique nanoporous structures, which function as the ion transport channels in redox flow battery operation, with an average pore size of 38nm and a porosity of 48%. This separator has produced excellent electrochemical performance in the all-vanadium mixed-acid system with energy efficiency delivery comparable to Nafion membrane and superior rate capability and temperature tolerance. The separator also demonstrates an exceptional capacity retention capability over extended cycling, offering additional operational latitude towards conveniently mitigating the capacity decay that is inevitable for Nafion. Because of the inexpensive raw materials and simple preparation protocol, the separator is particularly low-cost, estimated to be at least an order of magnitude more inexpensive than Nafion. Plus the proven chemical stability due to the same backbone material as Nafion, this separator possesses a good combination of critical membrane requirements and shows great potential to promote market penetration of the all-vanadium redox flow battery by enabling significant reduction of capital and cycle costs.

Wei, Xiaoliang; Nie, Zimin; Luo, Qingtao; Li, Bin; Chen, Baowei; Simmons, Kevin L.; Sprenkle, Vincent L.; Wang, Wei

2013-09-02T23:59:59.000Z

388

Role of alkyl alcohol on viscosity of silica-based chemical gels for decontamination of highly radioactive nuclear facilities  

SciTech Connect

Silica-based chemical gel for the decontamination of nuclear facilities was prepared by using fumed silica as a viscosifier, a 0.5 M Ce (IV) solution dissolved in concentrated nitric acid as a chemical decontamination agent, and tripropylene glycol butyl ether (TPGBE) as a co-viscosifier. A new effective strategy for the preparation of the chemical gel was investigated by introducing the alkyl alcohols as organic solvents to effectively dissolve the co-viscosifier. The mixture solution of the co-viscosifier and alkyl alcohols was more effective in the control of viscosity than that of the co-viscosifier only in gel. Here, the alkyl alcohols played a key role as an effective dissolution solvent for the co-viscosifier in the preparation of the chemical gel, resulting in a reducing of the amount of the co-viscosifier and gel time compared with that of the chemical gel prepared without the alkyl alcohols. It was considered that the alkyl alcohols contributed to the effective dissolution of the co-viscosifier as well as the homogeneous mixing in the formation of the gel, while the co-viscosifier in an aqueous media of the chemical decontamination agent solution showed a lower solubility. The decontamination efficiency of the chemical gels prepared in this work using a multi-channel analyzer (MCA) showed a high decontamination efficiency of over ca. 94% and ca. 92% for Co-60 and Cs-137 contaminated on surface of the stainless steel 304, respectively. (authors)

Choi, B. S.; Yoon, S. B.; Jung, C. H.; Lee, K. W.; Moon, J. K. [Div. of Decontamination and Decommissioning Technology Development, Korea Atomic Energy Research Inst., Daedeok-daero 989-111, Yuseong-gu, Daejeon, 305-353 (Korea, Republic of)

2012-07-01T23:59:59.000Z

389

Quasi-continuum photoluminescence: Unusual broad spectral and temporal characteristics found in defective surfaces of silica and other materials  

SciTech Connect

We previously reported a novel photoluminescence (PL) with a distribution of fast decay times in fused silica surface flaws that is correlated with damage propensity by high fluence lasers. The source of the PL was not attributable to any known silica point defect. Due to its broad spectral and temporal features, we here give this PL the name quasi-continuum PL (QC-PL) and describe the features of QC-PL in more detail. The primary features of QC-PL include broad excitation and emission spectra, a broad distribution of PL lifetimes from 20 ps to 5?ns, continuous shifts in PL lifetime distributions with respect to emission wavelength, and a propensity to photo-bleach and photo-brighten. We found similar PL characteristics in surface flaws of other optical materials, including CaF{sub 2}, DKDP, and quartz. Based on the commonality of the features in different optical materials and the proximity of QC-PL to surfaces, we suggest that these properties arise from interactions associated with high densities of defects, rather than a distribution over a large number of types of defects and is likely found in a wide variety of structures from nano-scale composites to bulk structures as well as in both broad and narrow band materials from dielectrics to semiconductors.

Laurence, Ted A., E-mail: laurence2@llnl.gov; Bude, Jeff D.; Shen, Nan; Steele, William A.; Ly, Sonny [Physical and Life Sciences and National Ignition Facility, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550 (United States)

2014-02-28T23:59:59.000Z

390

Liquid n-hexane condensed in silica nanochannels: A combined optical birefringence and vapor sorption isotherm study  

E-Print Network (OSTI)

The optical birefringence of liquid n-hexane condensed in an array of parallel silica channels of 7nm diameter and 400 micrometer length is studied as a function of filling of the channels via the vapor phase. By an analysis with the generalized Bruggeman effective medium equation we demonstrate that such measurements are insensitive to the detailed geometrical (positional) arrangement of the adsorbed liquid inside the channels. However, this technique is particularly suitable to search for any optical anisotropies and thus collective orientational order as a function of channel filling. Nevertheless, no hints for such anisotropies are found in liquid n-hexane. The n-hexane molecules in the silica nanochannels are totally orientationally disordered in all condensation regimes, in particular in the film growth as well as in the the capillary condensed regime. Thus, the peculiar molecular arrangement found upon freezing of liquid n-hexane in nanochannel-confinement, where the molecules are collectively aligned perpendicularly to the channels' long axes, does not originate in any pre-alignment effects in the nanoconfined liquid due to capillary nematization.

Andriy V. Kityk; Klaus Knorr; Patrick Huber

2009-07-20T23:59:59.000Z

391

X-ray study of the electric double layer at the n-hexane/nanocolloidal silica interface  

E-Print Network (OSTI)

The spatial structure of the transition region between an insulator and an electrolyte solution was studied with x-ray scattering.The electron density profile across the n-hexane/silica sol interface (solutions with 5-nm, 7-nm, and 12-nm colloidal particles) agrees with the theory of the electrical double layer and shows separation of positive and negative charges. The interface consists of three layers, i.e., a compact layer of Na+, a loose monolayer of nanocolloidal particles as part of a thick diffuse layer, and a low-density layer sandwiched between them. Its structure is described by a model in which the potential gradient at the interface reflects the difference in the potentials of "image forces" between the cationic Na+ and anionic nanoparticles and the specific adsorption of surface charge. The density of water in the large electric field (1-10 GV/m) of the transition region and the layering of silica in the diffuse layer is discussed.

Aleksey M. Tikhonov

2006-09-11T23:59:59.000Z

392

Purification, Recovery, and Laser-Driven Fluorination of Silicon from Dissolved and Particulate Silica for the Measurement of Natural Stable Isotope Abundances  

Science Journals Connector (OSTI)

Purification, Recovery, and Laser-Driven Fluorination of Silicon from Dissolved and Particulate Silica for the Measurement of Natural Stable Isotope Abundances ... At least three simple techniques exist for this:? fusion of SiO2 with Na2CO3 to form water-soluble sodium silicate, dissolution in HF, or dissolution in NaOH. ...

Christina L. De La Rocha; Mark A. Brzezinski; Michael J. DeNiro

1996-11-01T23:59:59.000Z

393

doi:10.1016/j.gca.2004.10.029 Adsorbed silica in stalagmite carbonate and its relationship to past rainfall  

E-Print Network (OSTI)

doi:10.1016/j.gca.2004.10.029 Adsorbed silica in stalagmite carbonate and its relationship to past on dissolved Si in cave waters and on adsorbed Si in resulting speleothems are therefore investigated. Bedrock the controls on this incorporation. The content of such adsorbed Si may, however, provide useful information

Henderson, Gideon

394

Germania-glass-core silica-glass-cladding modified chemical-vapor deposition optical fibers: optical losses, photorefractivity, and Raman amplification  

Science Journals Connector (OSTI)

Germania-glass-core silica-glass-cladding single-mode fibers (?n as great as 0.143) with a minimum loss of 20 dB/km at 1.85 m were fabricated by modified chemical-vapor...

Mashinsky, V M; Neustruev, V B; Dvoyrin, V V; Vasiliev, S A; Medvedkov, O I; Bufetov, I A; Shubin, A V; Dianov, E M; Guryanov, A N; Khopin, V F; Salgansky, M Yu

2004-01-01T23:59:59.000Z

395

Unusual behavior of propane as a co-guest during hydrate formation in silica sand: Potential application to seawater desalination and carbon dioxide capture  

Science Journals Connector (OSTI)

Abstract We report an unusual behavior of hydrate formation in silica sand with gas mixtures containing propane as a co-guest. Based on morphology study we observed that propane as a co-guest has the ability to draw water dispersed in silica sand to the hydrate formation region and showed a tendency to result in drastic hydrate growth due to the migration of water molecules to the gas phase region. Hydrate nucleation occurred in the interstitial pore space between the silica sand particles and hydrate growth occurred in the gas phase above the silica sand bed and to sustain the hydrate growth, dispersed water was drawn towards the hydrate growth front. In addition, we elucidated the effect of sand bed height to maximize the growth rates utilizing this behavior that results in enhanced kinetics. We propose conceptual designs for utilizing this behavior of propane as a co-guest in sand for seawater desalination and an innovative approach to simultaneously capture carbon dioxide and desalinate seawater.

Ponnivalavan Babu; Rajnish Kumar; Praveen Linga

2014-01-01T23:59:59.000Z

396

Important Roles of Enthalpic and Entropic Contributions to CO2 Capture from Simulated Flue Gas and Ambient Air Using Mesoporous Silica Grafted Amines  

Science Journals Connector (OSTI)

The measurement of isosteric heats of adsorption of silica supported amine materials in the low pressure range (00.1 bar) is critical for understanding the interactions between CO2 and amine sites at low coverage and hence to the development of efficient ...

Mustafa A. Alkhabbaz; Praveen Bollini; Guo Shiou Foo; Carsten Sievers; Christopher W. Jones

2014-09-08T23:59:59.000Z

397

Progress in development of silica aerogel for particle- and nuclear-physics experiments at J-PARC  

E-Print Network (OSTI)

This study presents the advancement in hydrophobic silica aerogel development for use as Cherenkov radiators and muonium production targets. These devices are scheduled for use in several particle- and nuclear-physics experiments that are planned in the near future at the Japan Proton Accelerator Research Complex. Our conventional method to produce aerogel tiles with an intermediate index of refraction of approximately 1.05 is extended so that we can now produce aerogel tiles with lower indices of refraction (i.e., 1.03-1.04) and higher indices of refraction (i.e., 1.075-1.08); each with excellent transparency. A new production method, called pin drying, was optimized to produce larger area aerogels consistently with an ultrahigh index of refraction (>1.10). In addition, for use as a thermal-muonium-emitting material at room temperature, dedicated low-density aerogels were fabricated using the conventional method.

Makoto Tabata; Hideyuki Kawai

2014-10-09T23:59:59.000Z

398

Microwave-assisted synthesis of silica aerogel supported pt nanoparticles for self-humidifying proton exchange membrane fuel cell  

Science Journals Connector (OSTI)

In this study, the mesoporous silica aerogel supported Pt nanoparticle (SAP) was synthesized by the simple microwave-assisted method within 90s and characterized by WXRD and BET measurements. SAP was then used as a filler to prepare the self-humidifying Nafion-based composite membrane (N/SAP). The dispersion of the catalyst in N/SAP as well as the water uptake and proton conductivity of N/SAP were investigated. Compared to that of the recast Nafion membrane (RN), the water uptake and the proton conductivity of N/SAP was improved for about 38% and 109%, respectively. In addition, the power density of the PEMFC single cell fabricated with N/SAP at 50C was 1104mWcm?2 and 913mWcm?2 measured under the humidified condition and dry condition, respectively, which was approximately 91% and 5.5 times higher than that with RN membrane, respectively.

Cheng-Hsiu Tsai; Feng-Lien Yang; Ching-Hung Chang; Yui Whei Chen-Yang

2012-01-01T23:59:59.000Z

399

Progress in development of silica aerogel for particle- and nuclear-physics experiments at J-PARC  

E-Print Network (OSTI)

This study presents the advancement in hydrophobic silica aerogel development for use as Cherenkov radiators and muonium production targets. These devices are scheduled for use in several particle- and nuclear-physics experiments that are planned in the near future at the Japan Proton Accelerator Research Complex. Our conventional method to produce aerogel tiles with an intermediate index of refraction of approximately 1.05 is extended so that we can now produce aerogel tiles with lower indices of refraction (i.e., 1.03-1.04) and higher indices of refraction (i.e., 1.075-1.08); each with excellent transparency. A new production method, called pin drying, was optimized to produce larger area aerogels consistently with an ultrahigh index of refraction (>1.10). In addition, for use as a thermal-muonium-emitting material at room temperature, dedicated low-density aerogels were fabricated using the conventional method.

Tabata, Makoto

2014-01-01T23:59:59.000Z

400

Infrared study on the adsorption of CO and NO on silica-supported Pd and Pt-Pd  

SciTech Connect

The IR spectra of NO adsorbed on silica-supported palladium had bands at 1735 and 1645/cm, which were assigned to linearly bound NO and to NO linearly bound to low-coordinated palladium, respectively. Bands at 1980 and 2070/cm in the spectrum of CO adsorbed on palladium were assigned multiply coordinated and linear CO, respectively. Carbon monoxide was completely displaced from palladium by nitric oxide, preadsorbed nitric oxide was partly displaced from palladium by carbon monoxide, and carbon dioxide and nitrous oxide were formed in both processes. A band at 2180/cm provided evidence for adsorbed isocyanate species. All bands shifted to higher frequencies by approx. 10/cm for 1:1 palladium/platinum bimetallic clusters; the carbon monoxide was readily removed by evacuating at room temperature, a fact that my be used in catalyst surface area determinations.

Grill, C.M.; Gonzalez, R.D.

1980-04-17T23:59:59.000Z

Note: This page contains sample records for the topic "multicomponent geothermometers silica" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Thermal imaging investigation of modified fused silica at surface damage sites for understanding the underlying mechanisms of damage growth  

SciTech Connect

We use an infrared thermal imaging system in combination with a fluorescence microscope to map the dynamics of the local surface temperature and fluorescence intensity under cw, UV excitation of laser-modified fused silica within a damage site. Based on a thermal diffusion model, we estimate the energy deposited via linear absorption mechanisms and derive the linear absorption coefficient of the modified material. The results indicate that the damage growth mechanism is not entirely based on linear absorption. Specifically, the absorption cross-section derived above would prove insufficient to cause a significant increase in the temperature of the modified material under nanosecond, pulsed excitation (via linear absorption at ICF laser fluences). In addition, irreversible changes in the absorption cross-section following extended cw, UV laser exposure were observed.

Negres, R A; Burke, M W; DeMange, P; Sutton, S B; Feit, M D; Demos, S G

2006-11-01T23:59:59.000Z

402

Development and characterization of colloidal silica-based slow-release permanganate gel (SRP-G): Laboratory investigations  

Science Journals Connector (OSTI)

Abstract Slow-release permanganate ( MnO 4 - ) gel (SRP-G) is a hyper-saline \\{KMnO4\\} solution that can be used for treating large, dilute, or deep plumes of chlorinated solvents in groundwater. Ideally, the SRP-G injected into aquifers will slowly gelate to form MnO 4 - gel in situ, and the gel will slowly releases MnO 4 - . Objectives of this study were to develop SRP-G using colloidal silica as gelling solution, characterize its gelation and release kinetics, and delineate its dynamics in a saturated sandy media. The SRP-G exhibited a two-phase increase in viscosity: a lag phase characterized by little increase in viscosity followed by a short gelation phase. Gelation lag times of SRP-G solutions increased (from 0.5h to 13d) with decreasing \\{KMnO4\\} concentrations (from 25 to 8gL?1). Permanganate release from gelated SRP-G increased with increasing \\{KMnO4\\} concentrations, and was characterized as asymptotic release with initial peak (0.92.2mgmin?1) followed by more attenuated release. Gelation lag times of SRP-G flowing in sands (linear velocity=2.1md?1) increased (1, 3, and 6h) with decreasing \\{KMnO4\\} concentrations (25.0, 23.0, and 22.9gL?1). Permanganate release from gelated SRP-Gs continued for up to 3d and was characterized as asymptotic release with an initial peak release (?1.2gmin?1) followed by more attenuated release over 70h. Dilution of SRP-G by dispersion in porous media affects gelation and release kinetics. Increasing the silica concentration in the SRP-G may facilitate gelation and extend the duration of MnO 4 - release from emplaced SRP-G in porous media.

Eung Seok Lee; Neha Gupta

2014-01-01T23:59:59.000Z

403

Phase behavior of carbon dioxide confined in silica aerogel in the vicinity of the bulk critical point  

SciTech Connect

The small angle neutron scattering intensities from silica aerogel filled with carbon dioxide at different loading densities of the bulk fluid (0.3-0.65 g/cm{sup 3}) were measured at fixed volume condition as a function of decreasing temperature, from 35 to 25 C, to characterize the phase behavior of the confined CO2 about the critical point of the bulk CO{sub 2}. The data present no evidence of a bulklike phase transition of the confined CO{sub 2} in the explored parameter region. They show that the confined CO{sub 2} may be approximated as a two phase system. The first phase (liquid film) is formed by CO{sub 2} molecules at the silica surface, and the second phase (confined fluid) fills up the rest of the pore volume. The thickness {delta} of the liquid film as well as the scattering-length densities of the two phases were obtained by analyzing the Porod invariants and the oscillations observed in the Porod plots at each loading density and temperature. The resulting {delta} values vary in the range 25-45 {angstrom} depending on the temperature and loading density. The density of the liquid film is 1.5-2 times larger than that of the confined fluid, which in its turn exceeds the density of bulk CO{sub 2} at similar temperature and pressure. At the lowest temperature (25 C), the densities of the liquid film and confined fluid respectively approach 1.25 g/cm{sup 3} and 0.8 g/cm{sup 3} independently of the loading conditions.

Ciccariello, Salvino [Universita di Padova; Melnichenko, Yuri B [ORNL; He, Lilin [ORNL

2011-01-01T23:59:59.000Z

404

Geothermometry At Raft River Geothermal Area (1980) | Open Energy  

Open Energy Info (EERE)

Geothermometry At Raft River Geothermal Area (1980) Geothermometry At Raft River Geothermal Area (1980) Exploration Activity Details Location Raft River Geothermal Area Exploration Technique Geothermometry Activity Date 1980 Usefulness not indicated DOE-funding Unknown Notes Geothermometer temperatures of shallow samples suggest significant re-equilibration at temperatures below those found in the deep wells. Silica geothermometer temperatures of water samples from the deep wells are in reasonable agreement with measured temperatures, whereas Na-K-Ca temperatures are significantly higher than measured temperatures. The chemical characteristics of the water, as indicated by chloride concentration, are extremely variable in shallow and deep samples. Chloride concentrations of the deep samples range from 580 to 2200 mg/kg.

405

Geothermometry At Desert Queen Area (Garchar & Arehart, 2008) | Open Energy  

Open Energy Info (EERE)

Queen Area (Garchar & Arehart, 2008) Queen Area (Garchar & Arehart, 2008) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Geothermometry At Desert Queen Area (Garchar & Arehart, 2008) Exploration Activity Details Location Desert Queen Area Exploration Technique Geothermometry Activity Date Usefulness not indicated DOE-funding Unknown Notes Temperatures of the reservoir at depth are estimated to be between 92-141 degrees C and were calculated using the δ18O(SO4-H2O) geothermometer. It is unclear whether these temperatures reflect waters from the outflow zone of the Desert Peak geothermal system, or waters from a different reservoir at Desert Queen. Quartz, chalcedony, amorphous silica, Na-K-Ca, and δ18O(SO4-H2O) geothermometer calculations were performed.

406

SERI Desiccant Cooling Test Facility. Status report. Preliminary data on the performance of a rotary parallel-passage silica-gel dehumidifier  

SciTech Connect

This report describes the SERI Desiccant Cooling Test Facility. The facility can test bench-scale rotary dehumidifiers over a wide range of controlled conditions. We constructed and installed in the test loop a prototype parallel-passage rotary dehumidifier that has spirally wound polyester tape coated with silica gel. The initial tests gave satisfactory results indicating that approximately 90% of the silica gel was active and the overall Lewis number of the wheel was near unity. The facility has several minor difficulties including an inability to control humidity satisfactorily and nonuniform and highly turbulent inlet velocities. To completely validate the facility requires a range of dehumidifier designs. Several choices are available including constructing a second parallel-passage dehumidifier with the passage spacing more uniform.

Schultz, K.J.

1986-04-01T23:59:59.000Z

407

Remaining Sites Verification Package for the 100-F-44:4, Discovery Pipeline in Silica Gel Pit, Waste Site Reclassification Form 2008-030  

SciTech Connect

The 100-F-44:4, Discovery Pipeline in Silica Gel Pit subsite is located in the 100-FR-1 Operable Unit of the Hanford Site, near the location of the former 110-F Gas Storage Tanks structure. The 100-F-44:4 subsite is a steel pipe discovered October 17, 2004, during trenching to locate the 118-F-4 Silica Gel Pit. Based on visual inspection and confirmatory investigation sampling data, the 100-F-44:4 subsite is a piece of non-hazardous electrical conduit debris. The 100-F-44:4 subsite supports unrestricted future use of shallow zone soil and is protective of groundwater and the Columbia River. No residual contamination exists within the deep zone. Therefore, no deep zone institutional controls are required.

J. M. Capron

2008-09-23T23:59:59.000Z

408

Infrared spectroscopic studies of carbon monoxide adsorbed on a series of silica-supported copper catalysts in different oxidation states  

SciTech Connect

Infrared spectroscopy has been used to study the adsorption of carbon monoxide (358-493 K, 0.1-20 kPa) on four copper-on-silica (2-10 wt% Cu) catalysts prepared by the ion-exchange technique. The measurements are made for each sample in three different states: unreduced (predominantly Cu{sup 2+}), and reduced (Cu{sup 0}), and partially reoxidized in nitrous oxide (Cu{sup +}). On unreduced samples, a major absorption band between 2127 and 2132 cm{sup {minus}1} due to CO adsorbed on small CuO particles and a weak band at 2199 cm{sup {minus}1} due to CO on isolated Cu{sup 2+} ions incorporated in the silica surface have been identified. The former adsorption obeys a Langmuir isotherm with a heat of adsorption of 29 kJ/mol independent of CuO particle size and surface coverage. After catalyst reduction, the major absorption band lies between 2090 and 2113 cm{sup {minus}1} and arises from CO linearly bound to very small (1- to 5-nm) copper metal clusters. The observed frequency shifts indicate the presence of steps and terraces similar to low index Cu planes in very small particles (1- to 2-nm), and the presence of similar higher index Cu planes on larger clusters (2- to 5-nm). The absorption is described by a Freundlich isotherm with the heat of CO adsorption decreasing with coverage from 50 to 22 kJ/mol on bigger particles but more constant (27 to 22 kJ/mol) on small particles. A surface copper/CO atomic ratio increasing from 5 to 12 is established at equilibrium saturation between 358 and 493 K using extinction coefficients determined in this study. In the reduced catalysts, a weakly adsorbed ({Delta}H{sub a} = {minus}20 kJ/mol) species assigned to CO bound to isolated Cu{sup +} ions is also found and absorbs at 2175 cm{sup {minus}1}. The frequency of this band does not vary with catalyst loading and is not affected by reoxidation of the catalyst in nitrous oxide.

Kohler, M.A.; Wainwright, M.S.; Trimm, D.L.; Cant, N.W. (Macquarie Univ., New South Wales (Australia) Univ. of South Wales (Australia))

1989-05-01T23:59:59.000Z

409

Effect of rogue particles on the sub-surface damage of fused silica during grinding/polishing  

SciTech Connect

The distribution and characteristics of surface cracks (i.e., sub-surface damage or scratching) on fused silica formed during grinding/polishing resulting from the addition of rogue particles in the base slurry has been investigated. Fused silica samples (10 cm diameter x 1 cm thick) were: (1) ground by loose abrasive grinding (alumina particles 9-30 {micro}m) on a glass lap with the addition of larger alumina particles at various concentrations with mean sizes ranging from 15-30 {micro}m, or (2) polished (using 0.5 {micro}m cerium oxide slurry) on various laps (polyurethanes pads or pitch) with the addition of larger rogue particles (diamond (4-45 {micro}m), pitch, dust, or dried Ceria slurry agglomerates) at various concentrations. For the resulting ground samples, the crack distributions of the as-prepared surfaces were determined using a polished taper technique. The crack depth was observed to: (1) increase at small concentrations (>10{sup -4} fraction) of rogue particles; and (2) increase with rogue particle concentration to crack depths consistent with that observed when grinding with particles the size of the rogue particles alone. For the polished samples, which were subsequently etched in HF:NH{sub 4}F to expose the surface damage, the resulting scratch properties (type, number density, width, and length) were characterized. The number density of scratches increased exponentially with the size of the rogue diamond at a fixed rogue diamond concentration suggesting that larger particles are more likely to lead to scratching. The length of the scratch was found to increase with rogue particle size, increase with lap viscosity, and decrease with applied load. At high diamond concentrations, the type of scratch transitioned from brittle to ductile and the length of the scratches dramatically increased and extended to the edge of the optic. The observed trends can explained semi-quantitatively in terms of the time needed for a rogue particle to penetrate into a viscoelastic lap. The results of this study provide useful insights and 'rules-of-thumb' relating scratch characteristics observed on surfaces during optical glass fabrication to the characteristics rogue particles causing them and their possible source.

Suratwala, T I; Steele, R; Feit, M D; Wong, L; Miller, P E; Menapace, J A; Davis, P J

2007-05-02T23:59:59.000Z

410

A new N-hydroxyethyliminodiacetic acid modified coreshell silica phase for chelation ion chromatography of alkaline earth, transition and rare earth elements  

Science Journals Connector (OSTI)

Abstract Bare coreshell silica (1.7?m) has been modified with iminodiacetic acid functional groups via standard silane chemistry, forming a new N-hydroxyethyliminodiacetic acid (HEIDA) functionalised coreshell stationary phase. The column was applied in high-performance chelation ion chromatography and evaluated for the retention of alkaline earth, transition and heavy metal cations. The influence of nitric acid eluent concentration, addition of complexing agent dipicolinic acid, eluent pH and column temperature on the column performance was investigated. The efficiencies obtained for transition and heavy metal cations (and resultant separations) were comparable or better than those previously obtained for alternative fully porous silica based chelation stationary phases, and a similarly modified monolithic silica column, ranging from ?15 to 56?m HETP. Increasing the ionic strength of the eluent with the addition of KNO3 (0.75M) and increasing the column temperature (70C) facilitated the isocratic separation of a mixture of 14 lanthanides and yttrium in under 12min, with HETP averaging 18?m (7?m for Ce(III))

Nicola McGillicuddy; Ekaterina P. Nesterenko; Pavel N. Nesterenko; Elaine M. Stack; Jesse O. Omamogho; Jeremy D. Glennon; Brett Paull

2013-01-01T23:59:59.000Z

411

Visible Light-Driven Water Oxidation by Ir oxide Clusters Coupledto Single Cr Centers in Mesoporous Silica  

SciTech Connect

Visible light-induced water oxidation has been demonstrated at an Ir oxide nanocluster coupled to a single Cr{sup VI} site on the pore surface of MCM-41 mesoporous silica. The photocatalytic unit was assembled by the reaction of surface Cr=O groups with Ir(acac){sub 3} precursor followed by calcination at 300 C and bond formation monitored by FT-Raman and FT-IR spectroscopy. High-resolution Z-contrast electron micrographs of the calcined material combined with energy-dispersive X-ray spot analysis confirmed the occlusion of Ir oxide nanoparticles inside the mesopores. Oxygen evolution of an aqueous suspension of the Ir{sub x}O{sub y}-CrMCM-41 upon visible light irradiation of the Cr{sup VI}-O ligand-to-metal charge-transfer absorption was monitored mass-spectrometrically. Comparison of the product yields for samples with low Cr content (Cr/Si {le} 0.02) and high Cr content (Cr/Si = 0.05) indicates that only isolated Cr centers are capable of extracting electrons from Ir oxide clusters, while di- or polychromate species are not. Water oxidation at a multielectron-transfer catalyst coupled to a single metal center has not been demonstrated before. The ability to drive water oxidation with a single metal center as electron pump offers opportunities for coupling the oxygen-evolving photocatalytic unit to reducing sites in the nanoporous scaffold.

Nakamura, Ryuhei; Frei, Heinz

2006-07-10T23:59:59.000Z

412

ToF-SIMS evaluation of calcium-containing silica/?-PGA hybrid systems for bone regeneration  

Science Journals Connector (OSTI)

Abstract Inorganic/organic hybrids have great potential for the production of bioactive scaffolds which have tailored mechanical properties and degradation rates suitable for tissue engineering. For bone regeneration, calcium incorporation into hybrids at low temperatures is important due to its ability to stimulate new bone formation. As a consequence, understanding the homogeneity of the critical inorganic and organic components will be the key to the development of such hybrids. The aim of this interdisciplinary study was to use time-of-flight secondary ion mass spectrometry (ToF-SIMS) to determine the homogeneity of these critical components. We evaluated various solgel silica/?-polyglutamic acid (?-PGA) hybrid systems produced using different routes to introduce the calcium, thereby tailoring and optimizing hybrid syntheses and processing routes. Dimethyl carbonate (DMC) was used to improve the inorganic/organic coupling and its influence on the homogeneity of the hybrid structures was also examined. The results revealed that the calcium salt form of ?-PGA was promising for calcium incorporation since homogeneous products could be obtained. The ToF-SIMS data also indicated that the reaction time of hybrid synthesis and the timing of the addition of DMC can affect the homogeneity of hybrids.

Daming Wang; Jin Nakamura; Gowsihan Poologasundarampillai; Toshihiro Kasuga; Julian R. Jones; David S. McPhail

2014-01-01T23:59:59.000Z

413

Non-metallic nanomaterials in cancer theranostics: a review of silica- and carbon-based drug delivery systems  

Science Journals Connector (OSTI)

The rapid development in nanomaterials has brought great opportunities to cancer theranostics, which aims to combine diagnostics and therapy for cancer treatment and thereby improve the healthcare of patients. In this review we focus on the recent progress of several cancer theranostic strategies using mesoporous silica nanoparticles and carbon-based nanomaterials. Silicon and carbon are both group IV elements; they have been the most abundant and significant non-metallic substances in human life. Their intrinsic physical/chemical properties are of critical importance in the fabrication of multifunctional drug delivery systems. Responsive nanocarriers constructed using these nanomaterials have been promising in cancer-specific theranostics during the past decade. In all cases, either a controlled texture or the chemical functionalization is coupled with adaptive properties, such as pH-, light-, redox- and magnetic field- triggered responses. Several studies in cells and mice models have implied their underlying therapeutic efficacy; however, detailed and long-term invivo clinical evaluations are certainly required to make these bench-made materials compatible in real bedside circumstances.

Yu-Cheng Chen; Xin-Chun Huang; Yun-Ling Luo; Yung-Chen Chang; You-Zung Hsieh; Hsin-Yun Hsu

2013-01-01T23:59:59.000Z

414

Swellings due to alkali-silica reaction and delayed ettringite formation: Characterisation of expansion isotropy and effect of moisture conditions  

Science Journals Connector (OSTI)

This paper investigates the effect of different conditions on the development of concrete expansions due to alkali-silica reaction (ASR), delayed ettringite formation (DEF) and their combination. The presence of products of the two reactions has been observed during structure diagnosis. The aim of this research is to study the two reactions in concretes with close mix designs but with various types of aggregate and moisture conditions. Measurements performed in the three directions of stress-free specimens showed that DEF expansions could be considered as isotropic for stress-free material. DEF expansions were largely influenced by the storage conditions (immersed in water or in sealed conditions). The volume of storage water modified the kinetics. Under sealed conditions, no expansions were measured for mortar containing non-reactive aggregate, while small positive strains were obtained for mortar containing reactive aggregate. In all cases, new water supply caused fast, large expansions. The different effects of alkali leaching and moisture conditions on DEF and ASR expansions are discussed.

Hassina Bouzabata; Stphane Multon; Alain Sellier; Hacne Houari

2012-01-01T23:59:59.000Z

415

Imaging System to Measure Kinetics of Material Cluster Ejection During Exit-Surface Damage Initiation and Growth in Fused Silica  

SciTech Connect

Laser-induced damage on the surface of optical components typically is manifested by the formation of microscopic craters that can ultimately degrade the optics performance characteristics. It is believed that the damage process is the result of the material exposure to high temperatures and pressures within a volume on the order of several cubic microns located just below the surface. The response of the material following initial localized energy deposition by the laser pulse, including the timeline of events and the individual processes involved during this timeline, is still largely unknown. In this work we introduce a time-resolved microscope system designed to enable a detailed investigation of the sequence of dynamic events involved during surface damage. To best capture individual aspects of the damage timeline, this system is employed in multiple imaging configurations (such as multi-view image acquisition at a single time point and multi-image acquisition at different time points of the same event) and offers sensitivity to phenomena at very early delay times. The capabilities of this system are demonstrated with preliminary results from the study of exit-surface damage in fused silica. The time-resolved images provide information on the material response immediately following laser energy deposition, the processes later involved during crater formation or growth, the material ejecta kinetics, and overall material motion and transformation. Such results offer insight into the mechanisms governing damage initiation and growth in the optical components of ICF class laser systems.

Raman, R N; Negres, R A; Demos, S G

2009-10-29T23:59:59.000Z

416

Microstructural and nonlinear optical properties of silicatitania sol-gel film doped with PbS quantum dots  

Science Journals Connector (OSTI)

Thin silicatitania filmsdoped with different concentration of PbSquantum dots (PbS/oxide molar ratios ranging from 5% to 25%) were fabricated via a sol-gel route. The structuralproperties were studied by x-ray diffraction high-resolution transmission electron microscopy and Rutherford backscattering spectrometry. The PbS crystals were found to have a mean diameter in the range 2.33.5 nm with narrow size distribution. The resonant nonlinear optical properties were studied by the nonlinear m-line technique and degenerate four-wave mixing. High negative nonlinear refractive indices (n 2 ) were measured at 1.064 ?m. Different n 2 values were obtained for nanosecond excitation (n 2 =10 ?7 10 ?8 ? cm 2 /kW ) and for picosecond excitation (n 2 =10 ?9 10 ?10 ? cm 2 /kW ). The differences can be explained by saturation effects. Measurements at 532 nm showed n 2 values ten times higher than at 1.064 ?m. The response time of the nonlinearity for both wavelengths was below 35 ps.

A. Martucci; J. Fick; J. Schell; G. Battaglin; M. Guglielmi

1999-01-01T23:59:59.000Z

417

Trace element and REE composition of five samples of the Yucca Mountain calcite-silica deposits. Special report No. 8  

SciTech Connect

The attached materials document the results of part of a recent effort of geochemical sampling and analysis at Yucca Mountain and nearby regions. The efforts come as a result of interest in comprehensive analyses of rare earth elements (REE), lanthanum (La) through lutecium (Lu). Several additional, non-REE analyses were obtained as well. Commercially available REE analyses have proved to be insufficiently sensitive for geochemical purposes. Dr. Roman Schmitt at the Radiation Center at Oregon State University in Corvallis was sent five samples as a trial effort. The results are very encouraging. The purpose of compiling Dr. Schmitt`s report and the other materials is to inform the sponsor of his independent observations of these results and other information that sent to him. To provide a more complete appreciation of the utility of REE analyses a copy of Dave Vaniman`s recent article is included in which he notes that REE analyses from Yucca Mountain indicate the occurrence of two distinctly different REE patterns as do several other chemical parameters of the calcite-silica deposits. Our four samples with high equivalent CaCO{sub 3} were collected from sites we believe to be spring deposits. One sample, 24D, is from southern Crater Flat which is acknowledged by U.S.G.S. investigators to be a spring deposit. All four of these samples have REE patterns similar to those from the saturated zone reported by Vaniman.

Livingston, D.

1993-07-01T23:59:59.000Z

418

Improved Mobility Control for Carbon Dioxide (CO{sub 2}) Enhanced Oil Recovery Using Silica-Polymer-Initiator (SPI) Gels  

SciTech Connect

SPI gels are multi-component silicate based gels for improving (areal and vertical) conformance in oilfield enhanced recovery operations, including water-floods and carbon dioxide (CO{sub 2}) floods, as well as other applications. SPI mixtures are like-water when pumped, but form light up to very thick, paste-like gels in contact with CO{sub 2}. When formed they are 3 to 10 times stronger than any gelled polyacrylamide gel now available, however, they are not as strong as cement or epoxy, allowing them to be washed / jetted out of the wellbore without drilling. This DOE funded project allowed 8 SPI field treatments to be performed in 6 wells (5 injection wells and 1 production well) in 2 different fields with different operators, in 2 different basins (Gulf Coast and Permian) and in 2 different rock types (sandstone and dolomite). Field A was in a central Mississippi sandstone that injected CO{sub 2} as an immiscible process. Field B was in the west Texas San Andres dolomite formation with a mature water-alternating-gas miscible CO{sub 2} flood. Field A treatments are now over 1 year old while Field B treatments have only 4 months data available under variable WAG conditions. Both fields had other operational events and well work occurring before/ during / after the treatments making definitive evaluation difficult. Laboratory static beaker and dynamic sand pack tests were performed with Ottawa sand and both fields core material, brines and crude oils to improve SPI chemistry, optimize SPI formulations, ensure SPI mix compatibility with field rocks and fluids, optimize SPI treatment field treatment volumes and methods, and ensure that strong gels set in the reservoir. Field quality control procedures were designed and utilized. Pre-treatment well (surface) injectivities ranged from 0.39 to 7.9 MMCF/psi. The SPI treatment volumes ranged from 20.7 cubic meters (m{sup 3}, 5460 gallons/ 130 bbls) to 691 m{sup 3} (182,658 gallons/ 4349 bbls). Various size and types of chemical/ water buffers before and after the SPI mix ensured that pre-gelled SPI mix got out into the formation before setting into a gel. SPI gels were found to be 3 to 10 times stronger than any commercially available cross-linked polyacrylamide gels based on Penetrometer and Bulk Gel Shear Testing. Because of SPIs unique chemistry with CO{sub 2}, both laboratory and later field tests demonstrated that multiple, smaller volume SPI treatments maybe more effective than one single large SPI treatment. CO{sub 2} injectivities in injection well in both fields were reduced by 33 to 70% indicating that injected CO{sub 2} is now going into new zones. This reduction has lasted 1+ year in Field A. Oil production increased and CO{sub 2} production decreased in 5 Field A production wells, offsets to Well #1 injector, for a total of about 2,250 m{sup 3} (600,000 gallons/ 14,250 bbls) of incremental oil production- a $140 / SPI bbl return. Treated marginal production well, Field A Well #2, immediately began showing increased oil production totaling 238 m{sup 3} (63,000 gallons/ 1500 BBLs) over 1 year and an immediate 81% reduced gas-oil ratio.

Oglesby, Kenneth

2014-01-31T23:59:59.000Z

419

Internalization of mesoporous silica nanoparticles induces transient but not sufficient osteogenic signals in human mesenchymal stem cells  

SciTech Connect

The biocompatibility of nanoparticles is the prerequisite for their applications in biomedicine but can be misleading due to the absence of criteria for evaluating the safety and toxicity of those nanomaterials. Recent studies indicate that mesoporous silica nanoparticles (MSNs) can easily internalize into human mesenchymal stem cells (hMSCs) without apparent deleterious effects on cellular growth or differentiation, and hence are emerging as an ideal stem cell labeling agent. The objective of this study was to thoroughly investigate the effect of MSNs on osteogenesis induction and to examine their biocompatibility in hMSCs. Uptake of MSNs into hMSCs did not affect the cell viability, proliferation and regular osteogenic differentiation of the cells. However, the internalization of MSNs indeed induced actin polymerization and activated the small GTP-bound protein RhoA. The MSN-induced cellular protein responses as believed to cause osteogenesis of hMSCs did not result in promotion of regular osteogenic differentiation as analyzed by cytochemical stain and protein activity assay of alkaline phosphatase (ALP). When the effect of MSNs on ALP gene expression was further examined by reverse transcriptase polymerase chain reaction, MSN-treated hMSCs were shown to have significantly higher mRNA expression than control cells after 1-hour osteogenic induction. The induction of ALP gene expression by MSNs, however, was absent in cells after 1-day incubation with osteogenic differentiation. Together our results show that the internalization of MSNs had a significant effect on the transient protein response and osteogenic signal in hMSCs, thereby suggesting that the effects of nanoparticles on diverse aspects of cellular activities should be carefully evaluated even though the nanoparticles are generally considered as biocompatible at present.

Huang, D.-M. [Center for Nanomedicine Research, National Health Research Institutes, Miaoli 350, Taiwan (China)], E-mail: dmhuang@nhri.org.tw; Chung, T.-H. [Stem Cell Research Center, National Health Research Institutes, Miaoli 350, Taiwan (China); Hung, Y.; Lu, F.; Wu, S.-H.; Mou, C.-Y. [Department of Chemistry, National Taiwan University, Taipei 106, Taiwan (China); Yao, M. [Department of Laboratory Medicine, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei 100, Taiwan (China); Chen, Y.-C. [Stem Cell Research Center, National Health Research Institutes, Miaoli 350, Taiwan (China); Department of Laboratory Medicine, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei 100, Taiwan (China); Department of Forensic Medicine, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei 100, Taiwan (China)], E-mail: ycchenmd@ntu.edu.tw

2008-09-01T23:59:59.000Z

420

Hydrogenolysis of methyl formate over copper on silica. I. Study of surface species by in situ infrared spectroscopy  

SciTech Connect

The hydrogenolysis of methyl formate to methanol over silica-supported copper has been studied using in situ infrared spectroscopy coupled with simultaneous determination of rate. Under flow reaction conditions two forms of adsorbed methyl formate exist. One has a carbonyl absorption at 1726 cm/sup -1/ and is bound to the support by the hydrogen bonding with a heat of adsorption of 65 kJ mol/sup -1/. The second absorbs at 1666 cm/sup -1/ and is bound to copper with an approximate heat of adsorption of 140 kJ mol/sup -1/. At 457 K the hydrogenolysis rate is directly proportional to the band intensity of the latter and hence it, or another species in equilibrium with it, is involved in the rate-determining step. Adsorption of CO from CO/H/sub 2/ mixtures gives rise to a single infrared band at 2117 cm/sup -1/, the corresponding heat of adsorption being 60 kJ mol/sup -1/. Competitive measurements under hydrogenolysis conditions show that methyl formate will partially displace adsorbed CO and not vice versa. Nonetheless CO does reversibly inhibit the rate and this is attributed to its adsorption displacing hydrogen from the surface. The lower concentration of surface hydrogen also reduces the rate of hydrogenation of a formaldehyde intermediate leading to its deposition as a polymer as revealed by infrared bands at 1483 and 1375 cm/sup -1/. The same polymer accretes more rapidly during the reverse methanol to methyl formate reaction for which CO is a substantial by-product and hydrogen pressures are much lower than used for hydrogenolysis. Continuous deactivation of the catalyst is then observed.

Monti, D.M.; Cant, N.W.; Trimm, D.L.; Wainwright, M.S.

1986-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "multicomponent geothermometers silica" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Controlled Assembly of Heterobinuclear Sites on Mesoporous Silica: Visible Light Charge-Transfer Units with Selectable Redox Properties  

SciTech Connect

Mild synthetic methods are demonstrated for the selective assembly of oxo-bridged heterobinuclear units of the type TiOCrIII, TiOCoII, and TiOCeIII on mesoporous silica support MCM-41. One method takes advantage of the higher acidity and, hence, higher reactivity of titanol compared to silanol OH groups towards CeIII or CoII precursor. The procedure avoids the customary use of strong base. The controlled assembly of the TiOCr system exploits the selective redox reactivity of one metal towards another (TiIII precursor reacting with anchored CrVI centers). The observed selectivity for linking a metal precursor to an already anchored partner versus formation of isolated centers ranges from a factor of six (TiOCe) to complete (TiOCr, TiOCo). Evidence for oxo bridges and determination of the coordination environment of each metal centers is based on K-edge EXAFS (TiOCr), L-edge absorption spectroscopy (Ce), and XANES measurements (Co, Cr). EPR, optical, FT-Raman and FT-IR spectroscopy furnish additional details on oxidation state and coordination environment of donor and acceptor metal centers. In the case of TiOCr, the integrity of the anchored group upon calcination (350 oC) and cycling of the Cr oxidation state is demonstrated. The binuclear units possess metal-to-metal charge-transfer transitions that absorb deep in the visible region. The flexible synthetic method for assembling the units opens up the use of visible light charge transfer pumps featuring donor or acceptor metals with selectable redox potential.

Frei, Heinz; Han, Hongxian; Frei, Heinz

2008-06-04T23:59:59.000Z

422

Simulation of Infrared Laser Heating of Silica Using Heat Conduction and Multifrequency Radiation Diffusion Equations Adapted for Homogeneous Refractive Lossy Media  

SciTech Connect

Localized, transient heating of materials using micro-scale, highly absorbing laser light has been used in many industries to anneal, melt and ablate material with high precision. Accurate modeling of the relative contributions of conductive, convective and radiative losses as a function of laser parameters is essential to optimizing micro-scale laser processing of materials. In bulk semi-transparent materials such as silicate glass melts, radiation transport is known to play a significantly larger role as the temperature increases. Conventionally, radiation is treated in the frequency-averaged diffusive limit (Rosseland approximation). However, the role and proper treatment of radiative processes under rapidly heated, high thermal gradient conditions, often created through laser-matter interactions, is at present not clear. Starting from the radiation transport equation for homogeneous, refractive lossy media, they derive the corresponding time-dependent multi-frequency diffusion equations. Zeroth and first moments of the transport equation couple the energy density, flux and pressure tensor. The system is closed by neglecting the temporal derivative of the flux and replacing the pressure tensor by its diagonal analogue. The radiation equations are coupled to a diffusion equation for the matter temperature. They are interested in modeling infrared laser heating of silica over sub-millimeter length scales, and at possibly rapid rates. Hence, in contrast to related work, they retain the temporal derivative of the radiation field. They derive boundary conditions at a planar air-silica interface taking account of reflectivities obtained from the Fresnel relations that include absorption. The effect of a temperature-dependent absorption index is explored through construction of a multi-phonon dielectric function that includes mode dispersion. The spectral dimension is discretized into a finite number of intervals yielding a system of multigroup diffusion equations. Simulations are presented. To demonstrate the bulk heat loss due to radiation and the effect of the radiation's temporal derivative, they model cooling of a silica slab, initially at 2500 K, for 10 s. Retaining the derivative enables correctly modeling the loss of photons initially present in the slab. Other simulations model irradiating silica discs (of approximately 5 mm radii and thickness) with a CO2 laser: {lambda} = 10.59 and 4.6 um, Gaussian profile, r{sub 0} = 0.5 mm for 1/e decay. By surrounding the disks in room-temperature air, they make use of the boundary conditions described above.

Shestakov, A I; Matthews, M J; Vignes, R M; Stolken, J S

2010-10-28T23:59:59.000Z

423

Multicomponent Synthesis of 3-Heteroarylpropionic Acids  

Science Journals Connector (OSTI)

Mauro F. A. Adamo * and Eleanor F. Duffy ... Adamo, Mauro F. A.; Donati, Donato; Duffy, Eleanor F.; Sarti-Fantoni, Piero ... Adamo, Mauro F. A.; Baldwin, Jack E.; Adlington, Robert M. ...

Mauro F. A. Adamo; Eleanor F. Duffy

2006-10-05T23:59:59.000Z

424

Multicomponent Synthesis of 3-Indolepropionic Acids  

Science Journals Connector (OSTI)

Mauro F. A. Adamo * and Vivekananda R. Konda ... Adamo, Mauro F. A.; Donati, Donato; Duffy, Eleanor F.; Sarti-Fantoni, Piero ... Adamo, Mauro F. A.; Baldwin, Jack E.; Adlington, Robert M. ...

Mauro F. A. Adamo; Vivekananda R. Konda

2006-12-15T23:59:59.000Z

425

Model for a multicomponent quantum system  

Science Journals Connector (OSTI)

In a recent paper, Lai introduced a lattice-gas model. In this paper we generalize Lai's model, making application to various systems such as dilute Heisenberg magnets, higher-spin systems, and a lattice of SU(3) triplets. By a careful consideration of general thermodynamic stability, and by variational arguments, we demonstrate Lai's solution to be incorrect, and in turn produce the correct solution in this case and in other cases including higher-dimensional models. The remaining cases we treat in one dimension by Bethe's ansatz, reducing the problem to coupled integral equations. We locate the singularities of the ground-state energy in the phase plane; and we explicitly calculate the absolute-ground-state energy, excitations above the absolute ground state, and the first correction to the absolute ground state for small concentrations of impurities.

Bill Sutherland

1975-11-01T23:59:59.000Z

426

Phase Stability of Multicomponent NAPLs Containing PAHs  

E-Print Network (OSTI)

to produce complex synthetic NAPLs which can be used as surrogate materials to simulate the behavior of a contaminant is dependent on its phase state. For solid phase contaminants in contact with water, the maximum assessment, predicting remediation effectiveness, and experimental research. In this paper, we discuss NAPL

Peters, Catherine A.

427

Advancements in isocyanide based multicomponent reactions  

E-Print Network (OSTI)

Wiley: New York, London, Ugi, I. ; Dmling, A. Angew. Chem.Chem. Ital. 1921, 51, 181-189. Ugi, I. Angew. Chem. Int. Ed.c) Hanusch-Kompa, C. ; Ugi, I. Tetrahedron Lett. 1998, 39,

Isaacson, Jerry Calhoun

2009-01-01T23:59:59.000Z

428

Multicomponent Reactions in Total Synthesis Kevin Allan  

E-Print Network (OSTI)

· Ugi Reaction · Cycloadditions · Povarov Reaction · Knoevenagel / Hetero-Diels-Alder Cycloaddition · 1-VCH; Weinheim, 2005. Orru, R. V. A.; de Greef, M. Synthesis 2003, 10, 1471-1499. Ugi, I. Pure Appl. Chem. 2001, 73, 187-191. Bienaymé, H.; Hulme, C.; Oddon, G.; Schmitt, P. Chem. Eur. J. 2000, 6, 3321-3329. Ugi, I

Stoltz, Brian M.

429

Multi-component hydrogen storage material  

DOE Patents (OSTI)

A reversible hydrogen storage composition having an empirical formula of: Li.sub.(x+z)N.sub.xMg.sub.yB.sub.zH.sub.w where 0.4.ltoreq.x.ltoreq.0.8; 0.2.ltoreq.y.ltoreq.0.6; 0

Faheem, Syed A. (Huntley, IL); Lewis, Gregory J. (Santa Cruz, CA); Sachtler, J.W. Adriaan (Des Plaines, IL); Low, John J. (Schaumburg, IL); Lesch, David A. (Hoffman Estates, IL); Dosek, Paul M. (Joliet, IL); Wolverton, Christopher M. (Evanston, IL); Siegel, Donald J. (Ann Arbor, MI); Sudik, Andrea C. (Canton, MI); Yang, Jun (Canton, MI)

2010-09-07T23:59:59.000Z

430

Variably Saturated Flow and Multicomponent Biogeochemical Reactive...  

NLE Websites -- All DOE Office Websites (Extended Search)

site have identified the potential for stimulating indigenous bacteria to catalyze the conversion of aqueous uranium in the +6 oxidation state to immobile solid-associated...

431

Multicomponent isolation and analysis of polynuclear aromatics  

SciTech Connect

Semi-preparative scale high-pressure liquid chromatography using bonded normal-phase columns offers an attractive alternative to the classical solvent partition/adsorption column chromatographic procedure for obtaining polycyclic aromatic hydrocarbons (PAH) or a polycyclic aromatic amines (PAA) fraction of purity suitable for analysis by gas chromatography. Sample matrices ranging from fossil fuels to air particulate extracts can be fractionated successfully if the appropriate polarity column is chosen. The apparatus is low-cost, gives reproducible results, does not require an expensive solvent gradient programmer, and can operate unattended.

Tomkins, B.A.; Griest, W.H.; Caton, J.E.; Reagan, R.R.

1981-01-01T23:59:59.000Z

432

Advancements in isocyanide based multicomponent reactions  

E-Print Network (OSTI)

3916. (a) Newman, M. S. ; Beal, P. F. , III. J. Am. Chem.Chem. 1999, Newman, M. S. ; Beal, P. F. , III. J. Am. Chem.

Isaacson, Jerry Calhoun

2009-01-01T23:59:59.000Z

433

Competitive adsorption of (phosphorylated) ethoxylated styrene oxide polymer and polyacrylic acid on silica coated iron oxide pigment  

Science Journals Connector (OSTI)

Abstract The colloidal stabilization in waterbased paint is poorly understood due to its complexity in composition, usually containing mixtures of particles and of surface active agents (dispersants). In this study we make a step forward by analyzing the competitive adsorption of a few widely used dispersants on a typical inorganic pigment (70nm sized Fe2O3-based red pigment; surface treated with silica; negative zetapotential at pH?7). The supposition is that any particle type in paint needs sufficient adsorbed dispersant in order to be stable. Thus, we investigate, for two combinations of two dispersants, how they mutually affect their adsorption at that pigment. Also the single adsorption of these dispersants was investigated, thus in the absence of the other. The dispersants are an anionic, polyacrylic acid sodium salt (PANa; MW=15,000Da) in combination with a MW=1500Da blockcopolymer of styrene oxide (SO) and ethoxylene (EO), either or not endcapped by a phosphate group (P). The adsorption behavior was analyzed by size exclusion chromatography of the processed supernatant of the pigment dispersion. \\{PANa\\} and SOEOP adsorb for electrostatic reasons while SOEO has affinity only to an organic surface. \\{PANa\\} and SOEOP show regular single adsorption with a plateau starting at the critical micelle concentration (cmc). SOEO shows single adsorption only beyond its cmc based on the adsorption of full micelles. When in competition, with SO-EP-P/PANa the adsorption of SOEOP is lowered by ?65% while that of \\{PANa\\} is unchanged. With SOEO/PANa the surface active species behave like in single adsorption below the cmc, but beyond the cmc a complicated phase separation occurs that cannot be based on mixed micelles. The adsorption data of \\{PANa\\} are compromised by depletion of \\{PANa\\} from interstices between particles. The anionic dispersants adsorb to the silicium oxide coated iron oxide pigment with negative surface potential because of the presence of a pH dependent relatively small number of positive iron oxide surface sites.

Wim K. Wijting; Alexander van Reenen; Jozua Laven; Rolf A.T.M. van Benthem; Gijsbertus de With

2014-01-01T23:59:59.000Z

434

Zircon-scale insights into the history of a Supervolcano, Bishop Tuff, Long Valley, California, with implications for the Ti-in-zircon geothermometer  

Science Journals Connector (OSTI)

Rapid evacuation of magma from the chamber responsible for the Bishop Tuff of Long Valley caldera, eastern California (over~6...1; Wilson and Hildreth 1997), provides a nearly instantaneous glimpse into a volum...

Mary R. Reid; Jorge A. Vazquez

2011-02-01T23:59:59.000Z

435

Silica-polyamine composite materials for heavy metal ion removal, recovery, and recycling. 2. Metal ion separations from mine wastewater and soft metal ion extraction efficiency  

SciTech Connect

Silica-polyamine composites have been synthesized which have metal ion capacities as high as 0.84 mmol/g for copper ions removed from aqueous solutions. In previous reports it has been demonstrated that these materials survive more than 3,000 cycles of metal ion extraction, elution, and regeneration with almost no loss of capacity (less than 10%). This paper describes two modified silica-polyamine composite materials and reveals the results of tests designed to determine the effectiveness of these materials for extracting and separating metal ions from actual mining wastewater samples. Using these materials, the concentration of copper, aluminum, and zinc in Berkeley Pit mine wastewater is reduced to below allowable discharge limits. The recovered copper and zinc solutions were greater than 90% pure, and metal ion concentration factors of over 20 for copper were realized. Further, the ability of one of these materials to decrease low levels of the soft metals cadmium, mercury, and lead from National Sanitation Foundation recommended challenge levels to below Environmental Protection Agency allowable limits is also reported.

Fischer, R.J.; Pang, D.; Beatty, S.T.; Rosenberg, E.

1999-12-01T23:59:59.000Z

436

Enhanced accumulation and visible light-assisted degradation of azo dyes in poly(allylamine hydrochloride)-modified mesoporous silica spheres  

SciTech Connect

A new route for the economic and efficient treatment of azo dye pollutants is reported, in which surface-modified organic-inorganic hybrid mesoporous silica (MS) spheres were chosen as microreactors for the accumulation and subsequent photodegradation of pollutants in defined regions. The surface-modified silica materials were prepared by anchoring the polycationic species such as poly(allylamine hydrochloride) on MS spheres via a simple wet impregnation method. The as-synthesized spheres with well-defined porous structures exhibited 15 times of accumulating capacity for orange II and Congo red compared to that of the pure MS spheres. Diffuse reflectance UV-vis spectroscopy and confocal laser scanning microscopy demonstrated that the accumulated orange II and CR in defined MS spheres were rapidly degraded in the presence of Fenton reagent under visible radiation. Kinetics analysis in recycling degradation showed that the as-synthesized materials might be utilized as environment-friendly preconcentrators/microreactors for the remediation of dye wastewater.

Tao Xia [Key Laboratory for Nanomaterials of the Ministry of Education, Beijing University of Chemical Technology, Beijing 100029 (China)], E-mail: taoxia@yahoo.com; Liu Bing; Hou Qian; Xu Hui [Key Laboratory for Nanomaterials of the Ministry of Education, Beijing University of Chemical Technology, Beijing 100029 (China); Chen Jianfeng [Research Center of the Ministry of Education for High Gravity Engineering and Technology, Beijing University of Chemical Technology, Beijing 100029 (China)], E-mail: chenjf@mail.buct.edu.cn

2009-02-04T23:59:59.000Z

437

Dynamics of Propane in Silica Mesopores Formed upon PropyleneHydrogenation over Pt Nanoparticles by Time-Resolved FT-IRSpectroscopy  

SciTech Connect

Propylene hydrogenation over Pt nanoparticles supported onmesoporous silica type SBA-15 was monitored by time-resolved FT-IRspectroscopy at 23 ms resolution using short propylene gas pulses thatjoined a continuous flow of hydrogen in N2 (1 atm total pressure).Experiments were conducted in the temperature range 323-413 K. Propanewas formed within 100 milliseconds or faster. The CH stretching regionrevealed distinct bands for propane molecules emerging inside thenanoscale channels of the silica support. Spectral analysis gave thedistribution of the propane product between support and surrounding gasphase as function of time. Kinetic analysis showed that the escape ofpropane molecules from the channels occurred within hundreds ofmilliseconds (3.1 + 0.4 s-1 at 383 K). A steady state distribution ofpropane between gas phase and mesoporous support is established as theproduct is swept from the catalyst zone by the continuous flow ofhydrogen co-reactant. This is the first direct spectroscopic observationof emerging products of heterogeneous catalysis on nanoporous supportsunder reaction conditions.

Waslylenko, Walter; Frei, Heinz

2007-01-31T23:59:59.000Z

438

Study on separation of platinum group metals from high level liquid waste using macroporous (MOTDGA-TOA)/SiO{sub 2}-P silica-based absorbent  

SciTech Connect

The recovery of platinum group metals (PGMs) from high level liquid waste (HLLW) by macroporous silica-based adsorbent, (MOTDGA-TOA)/SiO{sub 2}-P has been developed by impregnating two extractants of N,N'-dimethyl-N,N'-di-n-octyl-thio-diglycolamide (MOTDGA) and tri-n-octylamine (TOA) into a silica/polymer composite support (SiO{sub 2}-P). The adsorption of Ru(III), Rh(III) and Pd(II) have been investigated in simulated HLLW by batch method. The adsorbent has shown good uptake property for Pd(II). In addition, the combined use of MOTDGA and TOA improved the adsorption of Ru(III) and Rh(III) better than the individual use of them. The usability of adsorbent in radiation fields was further confirmed by irradiation experiments. The adsorbent remained to have the uptake capability for PGMs over the absorbed dose of 100 kGy, corresponding with one really adsorbed by the adsorbent, and showed good retention capability for Pd(II) even at the absorbed dose of 800 kGy. The chromatographic separation of metal ions was demonstrated with the adsorbent packed column, there is no influence of Re(VII) (instead of Tc) on the excellent separation behavior of Pd(II). (authors)

Ito, Tatsuya [Department of Quantum Science and Energy Engineering, Graduate School of Engineering, Tohoku University, Aoba 6-6, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Japan Atomic Energy Agency, Tokai-mura Naka-gun, Ibarak319-1195 (Japan); Kim, Seong-Yun; Xu, Yuanlai; Hitomi, Keitaro [Cyclotron and Radioisotope Center, Tohoku University, Aoba 6-3, Aramaki, Aoba-ku, Sendai, Miyagi 980-8578 (Japan); Ishii, Keizo [Department of Quantum Science and Energy Engineering, Graduate School of Engineering, Tohoku University, Aoba 6-6, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Nagaishi, Ryuji; Kimura, Takaumi [Japan Atomic Energy Agency, Tokai-mura Naka-gun, Ibarak319-1195 (Japan)

2013-07-01T23:59:59.000Z

439

Inflammation and gene expression in the rat lung after instillation of silica nanoparticles: Effect of size, dispersion medium and particle surface charge  

Science Journals Connector (OSTI)

Abstract We investigated the effects of silica particles and nanoparticles (NPs) (50nm and 200nm) with a neutral and positively charged surface when dispersed in saline, bovine serum albumin (BSA) or lung lining fluid (LLF) 24h post instillation into the lungs of rats. There was a significant increase in the recruitment of neutrophils in animals instilled with 50nm plain and aminated \\{NPs\\} compared with 200nm particles when dispersed in saline or BSA, but not when dispersed in LLF. There was no evidence of toxicity or an increase in the albumin content of the bronchoalveolar lavage fluid. Immunostaining for the transcription factor Nrf2 in BAL cells indicated that there was a significant increase in nuclear colocalisation in animals treated with plain and aminated 50nm \\{NPs\\} compared with plain and aminated 200nm particles when dispersed in saline, but no difference was observed between 50nm and 200nm aminated particles when dispersed in BSA. There was no difference in nuclear colocalisation with any of the particle types dispersed in LLF. This study suggests that low dose intratracheal exposure to silica nanoparticles can produce an acute inflammatory response and that the dispersion medium may influence the magnitude of this response.

David M. Brown; Nilesh Kanase; Birgit Gaiser; Helinor Johnston; Vicki Stone

2014-01-01T23:59:59.000Z

440

Kinetics of Silica Polymerization  

E-Print Network (OSTI)

Geothermal Resource and Reservior Investigations of U S Bureau of Reclamation Leaseholds at East Mesa, Imperial Valley,

Weres, Oleh

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "multicomponent geothermometers silica" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Kinetics of Silica Polymerization  

E-Print Network (OSTI)

by the value of parameter IPR, which has a default value oft L I Specifying values of IPR in the range 1 6 will causethat described above the value'of IPR causes the gene ion of

Weres, Oleh

2011-01-01T23:59:59.000Z

442

Kinetics of Silica Polymerization  

E-Print Network (OSTI)

G. E Tardiff, "The LLL Geothermal Energy Program St s Reportmal Effluent Inj ection", Geothermal Energy Novelty Becomesfor Injection", Geothermal Energy Novelty Becomes Resource:

Weres, Oleh

2011-01-01T23:59:59.000Z

443

Silica, Hybrid Silica, Hydride Silica and Non-Silica Stationary Phases for Liquid Chromatography  

Science Journals Connector (OSTI)

......microm was named HPLC. The price one had to pay was a high pressure...Ascentis Express C18, Acquity Ethylene Bridged Hybrid (BEH). and...the shape of their peaks on ethylene hybrid stationary phase under...contrast to what is observed for ethylene hybrid stationary phases in......

Endler M. Borges

2014-09-01T23:59:59.000Z

444

Kinetics of Silica Polymerization  

E-Print Network (OSTI)

mal Effluent Inj ection", Geothermal Energy Novelty Becomesfor Injection", Geothermal Energy Novelty Becomes Resource:G. E Tardiff, "The LLL Geothermal Energy Program St s Report

Weres, Oleh

2011-01-01T23:59:59.000Z

445

Silica, Hybrid Silica, Hydride Silica and Non-Silica Stationary Phases for Liquid Chromatography  

Science Journals Connector (OSTI)

......Marcon G., Tolon-Becerra A. Inputs of heavy metals due to agrochemical use in tobacco fields in Brazil's Southern Region. Environmental...chromatography influence of sorbent character, mobile phase composition, and pH on retention of basic compounds. Journal of Chromatography......

Endler M. Borges

2014-09-01T23:59:59.000Z

446

Numerical simulation study of silica and calcite dissolution around a geothermal well by injecting high pH solutions with chelating agent.  

SciTech Connect

Dissolution of silica, silicate, and calcite minerals in the presence of a chelating agent (NTA) at a high pH has been successfully performed in the laboratory using a high-temperature flow reactor. The mineral dissolution and porosity enhancement in the laboratory experiment has been reproduced by reactive transport simulation using TOUGHREACT. The chemical stimulation method has been applied by numerical modeling to a field geothermal injection well system, to investigate its effectiveness. Parameters from the quartz monzodiorite unit at the Enhanced Geothermal System (EGS) site at Desert Peak (Nevada) were used. Results indicate that the injection of a high pH chelating solution results in dissolution of both calcite and plagioclase minerals, and avoids precipitation of calcite at high temperature conditions. Consequently reservoir porosity and permeability can be enhanced especially near the injection well.

Xu, Tianfu; Rose, Peter; Fayer, Scott; Pruess, Karsten

2009-02-01T23:59:59.000Z

447

The effect of pulse duration on the growth rate of laser-induced damage sites at 351 nm on fused silica surfaces  

SciTech Connect

Past work in the area of laser-induced damage growth has shown growth rates to be primarily dependent on the laser fluence and wavelength. More recent studies suggest that growth rate, similar to the damage initiation process, is affected by a number of additional parameters including pulse duration, pulse shape, site size, and internal structure. In this study, we focus on the effect of pulse duration on the growth rate of laser damage sites located on the exit surface of fused silica optics. Our results demonstrate, for the first time, a significant dependence of growth rate at 351 nm on pulse duration from 1 ns to 15 ns as {tau}{sup 0.3} for sites in the 50-100 {micro}m size range.

Negres, R A; Norton, M A; Liao, Z M; Cross, D A; Bude, J D; Carr, C W

2009-10-29T23:59:59.000Z

448

PMo or PW heteropoly acids supported on MCM-41 silica nanoparticles: Characterisation and FT-IR study of the adsorption of 2-butanol  

SciTech Connect

Mesoporous silica, prepared in basic conditions, has been loaded (20% weight) with 12-molybdophosphoric (PMo) or 12-tungstophosphoric (PW) acid and calcined at different temperatures ranging between 250 and 550 deg. C. The samples have been characterised by N{sub 2} adsorption-desorption at -196 deg. C, transmission electron microscopy (TEM), powder X-ray diffraction (PXRD), UV-visible diffuse reflectance, Raman spectroscopy and temperature programmed reduction (TPR). The acidity and catalytic activity have been, respectively, examined by monitoring the adsorption of pyridine and 2-butanol by FT-IR spectroscopy. The results indicate that PW and PMo acids are highly dispersed on mesoporous silica MCM-41 spherical nanoparticles. While PMo retains its Keggin structure up to 550 deg. C, PW decomposes at this temperature into crystalline WO{sub 3} and phosphorous oxides. In both cases, the morphology, hexagonal symmetry and long-range order observed for the support are preserved with calcination up to 450 deg. C. The Broensted-type acid sites found in all samples, whose surface concentration decreases as the calcination temperature increases, are responsible for the selective formation of cis-butene detected upon adsorption of 2-butanol. The sample containing PW calcined at 450 deg. C also shows selectivity to methyl ethyl ketone. - Graphical abstract: Samples based in MCM-41 nanoparticles loaded with tungstophosphoric and molybdophosphoric acids have been synthesised. The uncalcined solids and that derived upon their calcination in the temperature range 250-550 deg. C have been characterised and evaluated in the decomposition of 2-butanol monitored by FT-IR spectroscopy.

Carriazo, Daniel [GIR-QUESCAT, Dpto. de Quimica Inorganica, Universidad de Salamanca, 37008-Salamanca (Spain); Domingo, Concepcion [Instituto de Estructura de la Materia, C.S.I.C., Serrano, 123, 28006-Madrid (Spain); Martin, Cristina [GIR-QUESCAT, Dpto. de Quimica Inorganica, Universidad de Salamanca, 37008-Salamanca (Spain); Rives, Vicente [GIR-QUESCAT, Dpto. de Quimica Inorganica, Universidad de Salamanca, 37008-Salamanca (Spain)], E-mail: vrives@usal.es

2008-08-15T23:59:59.000Z

449

In-situ Spectroscopy of Water Oxidation at Ir Oxide Nanocluster Drivenby Visible TiOCr Charge-Transfer Chromophore in Mesoporous Silica  

SciTech Connect

An all-inorganic photocatalytic unit consisting of a binuclear TiOCr charge-transfer chromophore coupled to an Ir oxide nanocluster has been assembled on the pore surface of mesoporous silica AlMCM-41. In situ FT-Raman and EPR spectroscopy of an aqueous suspension of the resulting IrxOy-TiCr-AlMCM-41 powder reveal the formation of superoxide species when exciting the Ti(IV)OCr(III) --> Ti(III)OCr(IV) metal-to-metal charge-transfer chromophore with visible light. Use of H218O confirms that the superoxide species originates from oxidation of water. Photolysis in the absence of persulfate acceptor leads to accumulation of Ti(III) instead. The results are explained by photocatalytic oxidation of water at Ir oxide nanoclusters followed by trapping of the evolving O2 by transient Ti(III) centers to yield superoxide. Given the flexibility to select donor metals with appropriate redox potential, photocatalytic units consisting of a binuclear charge-transfer chromophore coupled to a water oxidation catalyst shown here constitute a step towards thermodynamically efficient visible light water oxidation units.

Frei, Heinz; Han, Hongxian; Frei, Heinz

2008-06-03T23:59:59.000Z

450

Research and Development of a New Silica-Alumina Based Cementitious Material Largely Using Coal Refuse for Mine Backfill, Mine Sealing and Waste Disposal Stabilization  

SciTech Connect

Coal refuse and coal combustion byproducts as industrial solid waste stockpiles have become great threats to the environment. To activate coal refuse is one practical solution to recycle this huge amount of solid waste as substitute for Ordinary Portland Cement (OPC). The central goal of this project is to investigate and develop a new silica-alumina based cementitious material largely using coal refuse as a constituent that will be ideal for durable construction, mine backfill, mine sealing and waste disposal stabilization applications. This new material is an environment-friendly alternative to Ordinary Portland Cement. The main constituents of the new material are coal refuse and other coal wastes including coal sludge and coal combustion products (CCPs). Compared with conventional cement production, successful development of this new technology could potentially save energy and reduce greenhouse gas emissions, recycle vast amount of coal wastes, and significantly reduce production cost. A systematic research has been conducted to seek for an optimal solution for enhancing pozzolanic reactivity of the relatively inert solid waste-coal refuse in order to improve the utilization efficiency and economic benefit as a construction and building material.

Henghu Sun; Yuan Yao

2012-06-29T23:59:59.000Z

451

Enhanced Gas Absorption in the Ionic Liquid 1-n-Hexyl-3-methylimidazolium Bis(trifluoromethylsulfonyl)amide ([hmim][Tf{sub 2}N]) Confined in Silica Slit Pores: A Molecular Simulation Study  

SciTech Connect

Two-dimensional NP{sub xy}T and isostress-osmotic (N{sub 2}P{sub xy}Tf{sub 1}) Monte Carlo simulations were used to compute the density and gas absorption properties of the ionic liquid (IL) 1-n-hexyl-3- methylimidazolium bis(Trifluoromethylsulfonyl)amide ([hmim][Tf{sub 2}N]) confined in silica slit pores (25-45 ). Self-diffusivity values for both gas and IL were calculated from NVE molecular dynamics simulations using both smooth and atomistic potential models for the silica. Simulations show that the molar volume for [hmim][Tf{sub 2}N] confined in 25-45 silica slit pores are 12-31% larger than for the bulk IL at 313-573 K and 1 bar. The amounts of CO{sub 2}, H{sub 2}, and N{sub 2} absorbed in the confined IL are typically 1.1-3 times larger than in the bulk IL due to larger molar volumes for the confined IL compared to the bulk IL. The CO{sub 2}, N{sub 2}, and H{sub 2} molecules are generally absorbed close to the silica wall where the IL density is very low. This arrangement causes the self-diffusivities for these gases in the confined IL to be 2 to 8 times larger than in the bulk IL at 298-573 K. The solubility for water in the confined and bulk ILs are similar, which is likely due to strong water interactions with [hmim][Tf{sub 2}N] through hydrogen-bonding resulting in the confined IL molar volume playing a less important role in determining H{sub 2}O solubility. Water molecules were largely absorbed in the IL-rich region rather than close to the silica wall. The self-diffusivities for water correlate with the confined IL. The confined IL exhibits self-diffusivities larger than the bulk IL at lower temperatures, but smaller than the bulk IL at higher temperatures. The findings from simulations are consistent with available experimental data for similar confined IL systems.

Shi, Wei; Luebke, David R.

2013-05-07T23:59:59.000Z

452

Effect of silica sand size on the formation kinetics of CO2 hydrate in porous media in the presence of pure water and seawater relevant for CO2 sequestration  

Science Journals Connector (OSTI)

Abstract Understanding the kinetics of carbon dioxide (CO2) hydrate formation in pure water, seawater and porous media aids in developing technologies for CO2 gas storage, carbon capture and sequestration (CCS) and potentially for methane production from methane hydrates. The present work is focused on understanding the kinetics of CO2 hydrate formation in pure water and seawater at an initial formation pressure of 6MPa (providing a driving force of about 4.0MPa) and a formation temperature of 276.15K with 75% water saturation in three silica sand particle sizes (0.16mm, 0.46mm and 0.92mm). The seawater (3.3wt% salinity) used in the present study is obtained from sea coast of Chennai (India). It is observed that the gas consumption of CO2 in hydrate is more for smaller silica sand particle and decreases as the size of the sand increases. The total gas consumed at the end of the seawater experiment is found to be less than the gas consumed at the end of the pure water experiment. This is due to the fact that salts in seawater act as a thermodynamic inhibitor resulting in lower gas consumption of CO2 in hydrate. The average rate of hydrate formation observed is optimum in 0.46mm particles and is observed to be higher as compared to 0.16 and 0.92mm particles over 10h experimental time. This indicates that 0.46mm silica sand provides an optimum environment for efficient hydrate formation. The study can be useful to understand the suitability of potential sandstone reservoir for CO2 sequestration in the form of hydrate in the presence of saline formation water.

Prathyusha Mekala; Marc Busch; Deepjyoti Mech; Rachit S. Patel; Jitendra S. Sangwai

2014-01-01T23:59:59.000Z

453

The initial stages of bioglass dissolution: a CarParrinello molecular-dynamics study of the glasswater interface  

Science Journals Connector (OSTI)

...doi:10.1021/jp805206z ) Car, R. , and M. Parrinello1985Unified...amorphous silica surfaces:a Car-Parrinello simulation studyJ...multicomponent silicate glasses:Car-Parrinello molecular dynamics...layers on defect-free and defective anatase TiO2(101) surfacesJ...

2011-01-01T23:59:59.000Z

454

Micromechanical properties of silica aerogels  

Science Journals Connector (OSTI)

Aerogels are nanostructured highly porous solids that present properties which are very different from other materials i.e. extremely low densities. In this letter the mechanical properties of aerogels have been studied with a nondestructive microindentation technique. This technique enables the continuous measurement of load-displacement curves during loading and unloading cycles by using very small indentation loads (?1 mN) small enough to prevent cracking of the aerogels. The samples studied show two different types of mechanical behaviors; the low-density aerogels are elastic while the denser aerogels behave as elastoplastic materials. Youngs modulus hardness and the elastic parameter have been evaluated for these aerogel samples. Power function relationships have been found between these mechanical parameters and the aerogel densities.

M. Moner-Girona; A. Roig; E. Molins; E. Mart??nez; J. Esteve

1999-01-01T23:59:59.000Z

455

Energies of strained silica rings  

Science Journals Connector (OSTI)

The energies of strained two-member and three-member rings of SiO4 tetrahedra are calculated using models based on continuous SiO2 networks. These rings are considered to form highly reactive ``defect'' centers in vitreous SiO2 and at its surface. The calculations are based on a generalized gradient approximation to density-functional theory, and give strain energies of 1.23 and 0.25 eV for two- and three-member rings, considerably smaller than those previously estimated from Hartree-Fock calculations applied to small hydrogen-terminated molecular models. Structural results are compared with experiment for solids and molecules containing such rings. Changes in bond charge densities due to ring strain are illustrated, and modifications of the electronic states of relaxed SiO2 networks caused by strained ring defects are discussed.

D. R. Hamann

1997-06-01T23:59:59.000Z

456

Tritium Release from Silica Glass  

Science Journals Connector (OSTI)

Material Interaction and Permeation / Proceedings of the Sixth International Conference on Tritium Science and Technology Tsukuba, Japan November 12-16, 2001

T.Tanifuji; S. Jitsukawa; S.Nasu; A.Moon; K.Mori; S.Nishikawa; M.Yamanaka; Y.Izawa

457

Exergy of multi-phase multi-component systems  

Science Journals Connector (OSTI)

We will emphasize the different definitions of the exergy used in the Anglo- Saxon thermodynamic literature ... we will demonstrate a practical application of the exergy.

Nikolay Ivanov Kolev

2012-01-01T23:59:59.000Z

458

Pulsar emission: Langmuir modes in a relativistic multicomponent plasma  

Science Journals Connector (OSTI)

......of magnitude larger than mode wavelengths...ion-proton plasma Lorentz factors...moderately large and would give...order of 1-MHz. The components of the plasma are of particular...two-component atmosphere in local thermodynamic...radiation from an area of the neutron-star......

P. B. Jones

2014-01-01T23:59:59.000Z

459

Boundary Integral Methods for Multicomponent Fluids and Multiphase Materials  

E-Print Network (OSTI)

integral methods in two dimensions to multi­component fluid flows and multi­phase problems in materials, and more recently to multi­phase problems in materials science. By multi­fluid or multi­phase we mean systems where the constituitive properties of the fluid or material change abruptly at a dividing

460

Baryonic Bound State of Vortices in Multicomponent Superconductors  

E-Print Network (OSTI)

We construct a bound state of three 1/3-quantized Josephson coupled vortices in three-component superconductors with intrinsic Josephson couplings, which may be relevant with regard to iron-based superconductors. We find a Y-shaped junction of three domain walls connecting the three vortices, resembling the baryonic bound state of three quarks in QCD. The appearance of the Y-junction (but not a Delta-junction) implies that in both cases of superconductors and QCD, the bound state is described by a genuine three-body interaction (but not by the sum of two-body interactions). We also discuss a confinement/deconfinement phase transition.

Muneto Nitta; Minoru Eto; Toshiaki Fujimori; Keisuke Ohashi

2010-11-11T23:59:59.000Z

Note: This page contains sample records for the topic "multicomponent geothermometers silica" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Subsalt pressure prediction from multicomponent seismics (and more!)  

Science Journals Connector (OSTI)

...velocities to formation pore pressure...of lithology, rock history, and...measured mud rock compressional...shear at a subsalt interface. The correlation...characterization and drillability assessment by...prediction ahead of the bit by Ebrom et al...properties reservoir rocks S-waves safety...

Dan Ebrom; Martin Albertin; Philip Heppard

462

Pulsar emission: Langmuir modes in a relativistic multicomponent plasma  

Science Journals Connector (OSTI)

......the real polar-cap plasma must be more complicated...The ion-proton plasma Lorentz factors considered...of the order of 1-MHz. The components of the plasma are of particular interest...giving a two-component atmosphere in local thermodynamic......

P. B. Jones

2014-01-01T23:59:59.000Z

463

Towards breaking temperature equilibrium in multi-component Eulerian schemes  

SciTech Connect

We investigate the effects ofthermal equilibrium on hydrodynamic flows and describe models for breaking the assumption ofa single temperature for a mixture of components in a cell. A computational study comparing pressure-temperature equilibrium simulations of two dimensional implosions with explicit front tracking is described as well as implementation and J-D calculations for non-equilibrium temperature methods.

Grove, John W [Los Alamos National Laboratory; Masser, Thomas [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

464

Multicomponent cnoidal waves in cascade parametric frequency conversion  

SciTech Connect

It is shown that four-mode interaction in quasi-synchronous cascade frequency conversion on a quadratic nonlinearity can be described in terms of an effective cubic nonlinearity, which reduces the problem to solving the system of two coupled nonlinear Schroedinger equations (NSEs) with respect to the amplitudes of waves involved in both nonlinear processes. Analytic solutions of a new type found for this system have the form of cnoidal waves with components representing the sum and difference of the identical fundamental solutions of the NSE with shifted arguments. The obtained solutions cover the entire range of variation of boundary conditions, allowing the optimisation of the conversion efficiency in any particular situation. (nonlinear optical phenomena)

Petnikova, V M; Shuvalov, Vladimir V [International Laser Center, M. V. Lomonosov Moscow State University, Moscow (Russian Federation)

2008-12-31T23:59:59.000Z

465

Multi-component Nanoparticle Based Lubricant Additive to Improve...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

of active nanoparticle additive for lubricatns that will minimize sulfur and phosporous content in engine oil, and lower ash forming elements deer08adhvaryu.pdf More Documents &...

466

Parallel Simulation of Bioreactive Multicomponent Transport Processes in  

E-Print Network (OSTI)

in the ground- water. Fortunately, biodegradation tends to attenuate at least some organics during goundwater remediation involving natural attenuation" (Bayerisches Ver- bundvorhaben \\Nachhaltige Altlastenbew

Kraeutle, Serge

467

Multi-component removal in flue gas by aqua ammonia  

DOE Patents (OSTI)

A new method for the removal of environmental compounds from gaseous streams, in particular, flue gas streams. The new method involves first oxidizing some or all of the acid anhydrides contained in the gas stream such as sulfur dioxide (SO.sub.2) and nitric oxide (NO) and nitrous oxide (N.sub.2O) to sulfur trioxide (SO.sub.3) and nitrogen dioxide (NO.sub.2). The gas stream is subsequently treated with aqua ammonia or ammonium hydroxide which captures the compounds via chemical absorption through acid-base or neutralization reactions. The products of the reactions can be collected as slurries, dewatered, and dried for use as fertilizers, or once the slurries have been dewatered, used directly as fertilizers. The ammonium hydroxide can be regenerated and recycled for use via thermal decomposition of ammonium bicarbonate, one of the products formed. There are alternative embodiments which entail stoichiometric scrubbing of nitrogen oxides and sulfur oxides with subsequent separate scrubbing of carbon dioxide.

Yeh, James T. (Bethel Park, PA); Pennline, Henry W. (Bethel Park, PA)

2007-08-14T23:59:59.000Z

468

MULTICOMPONENT SUBSPACE CHIRP PARAMETER ESTIMATION USING DISCRETE FRACTIONAL FOURIER ANALYSIS  

E-Print Network (OSTI)

of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration Daniel Jackson Peacock and Balasubramaniam Santhanam Department of E.C.E. University of New Mexico under contract DE-AC04-94AL85000. This work was supported by the US Department of Energy (award no. DE

Santhanam, Balu

469

Geothermometry At Upper Hot Creek Ranch Area (Benoit & Blackwell, 2006) |  

Open Energy Info (EERE)

Geothermometry At Upper Hot Creek Ranch Area (Benoit & Blackwell, 2006) Geothermometry At Upper Hot Creek Ranch Area (Benoit & Blackwell, 2006) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Geothermometry At Upper Hot Creek Ranch Area (Benoit & Blackwell, 2006) Exploration Activity Details Location Upper Hot Creek Ranch Area Exploration Technique Geothermometry Activity Date Usefulness useful DOE-funding Unknown Notes Ten water samples were collected for chemical analysis and interpretation. Analyses of three samples of the UHCR thermal give predicted subsurface temperatures ranging from 317 to 334 oF from the Na-K-Ca, silica (quartz), and Na-Li geothermometers. The fact that all three thermometers closely agree gives the predictions added credibility. References Dick Benoit, David Blackwell (2006) Exploration Of The Upper Hot

470

Parametric study of a silica gel-water adsorption refrigeration cycle -- The influence of thermal capacitance and heat exchanger UA-values on cooling capacity, power density, and COP  

SciTech Connect

The influence of heat exchanger UA-values (adsorber/desorber, evaporator, and condenser) is investigated for an adsorption chiller, with consideration given to the thermal capacitance of the adsorber/desorber by means of a lumped-parameter cycle simulation model developed by the authors and co-workers for the single-stage silica gel-water adsorption chiller. The closed-cycle-type chiller, for use in air conditioning, is driven by low-grade waste heat (85 C [185 F]) and cooled by water at 31 C (88 F) and operates on relatively short cycle times (420 seconds adsorption/desorption; 30 second adsorber/desorber sensible cooling and heating). The results showed cycle performance to be considerably affected by the thermal capacitance and UA-value of the adsorber/desorber, which is attributed to the severe sensible cooling/heating requirements resulting from batched cycle operation. The model is also sensitive to the evaporator UA-value--but to a lesser extent. The condenser UA-value is the least sensitive parameter due to the working pair adsorption behavior in the temperature range defined for desorption and condensation.

Boelman, E.C.; Saha, B.B.; Kashiwagi, Takao [Tokyo Univ. of Agriculture and Technology (Japan). Dept. of Mechanical Systems Engineering

1997-12-31T23:59:59.000Z

471

Adsorption of Ambient Moisture by Silica Aerogel  

Science Journals Connector (OSTI)

Technical Paper / Selected papers from 20th Target Fabrication Meeting, May 20-24, 2012, Santa Fe, NM, Guest Editor: Robert C. Cook

Christopher E. Hamilton; Nickolaus A. Smith; Jon R. Schoonover; Kimberly A. Defriend Obrey; Nicholas Bazin; Tina Jewell

472

Selective Adsorbents from Ordered Mesoporous Silica  

Science Journals Connector (OSTI)

The amino-containing OMS?NH2 adsorbent has a large adsorption capacity and a strong affinity for the Acid blue 25. ... Furthermore, these adsorbents can be regenerated by simple washing with alkaline or acid solution to recover both the adsorbents and the adsorbed dyes. ...

Ka Yee Ho; Gordon McKay; King Lun Yeung

2003-02-14T23:59:59.000Z

473

LimeAluminaSilica processing incorporating minerals  

Science Journals Connector (OSTI)

The use of naturally occurring minerals to enhance the physical and mechanical properties of industrial ceramics such as alumina is an attractive alternative to synthetic materials due to cost, chemical stability and availability. Two systems, have been chosen for investigation, aluminakyanite to produce an aluminamullite composite and aluminawollastonite to produce a lime aluminosilicate. Wet processing conditions were optimised using pH/rheology and microelectrophoresis techniques followed by slip casting. The resulting green compacts were subjected to a variety of sintering regimes to produce the desired composites. Sintered products were characterised by techniques such as electron probe microanalysis, hardness tests and toughness determinations. Results are discussed, both in terms of enhanced properties realised (toughness, wear resistance, dielectric), and with respect to the viability of using natural minerals in this application.

R.H Bryden; D.G Goski; W.F Caley

1999-01-01T23:59:59.000Z

474

CHEMISTRY OF SILICA IN CERRO PRIETO BRINES  

E-Print Network (OSTI)

lfuen operated w:l.thout sludge recirculation, this pilotcould lead to problems with sludge accumulation there. Ifby recirculation of part of the sludge coming out of the

Weres, O.

2012-01-01T23:59:59.000Z

475

Silica grain catalysis of methanol formation  

Science Journals Connector (OSTI)

......molecules such as acetaldehyde (CH3CH=O), acetylene (C2H2), ethylene (C2H4) and hydrogen cyanide (HCN) where the double and...Surf. Sci., 500, 823. Williams D. A. , Brown W. A., Price S. D., Rawlings J. M. C., Viti S., 2007, Astron......

T. P. M. Goumans; Adrian Wander; C. Richard A. Catlow; Wendy A. Brown

2007-12-21T23:59:59.000Z

476

Monolithic Silica Stationary Phases in Liquid Chromatography  

Science Journals Connector (OSTI)

......second peak), trypsin inhibitor (third peak) (60). A...modified subsequently by chitosan and 2,6-sialyllactose...Different ratio of phosphate 97 inhibitors rofecoxib buffer & acetonitrile...determination of cyclooxygenase II inhibitors in human plasma. J. Chromatogr......

Imran Ali; Vinay D. Gaitonde; Hassan Y. Aboul-Enein

2009-07-01T23:59:59.000Z

477

Chemistry of Silica in Cerro Prieto Brines  

E-Print Network (OSTI)

data was generated by t e CFE Laioratory a t Cerro Prietowere performed a t the CFE Laboratory a t Cerro P r i e t oe h e l p of J,. Fausto L of CFE. Brine from Cerro P r i e t

Weres, Oleh

2012-01-01T23:59:59.000Z

478

CHEMISTRY OF SILICA IN CERRO PRIETO BRINES  

E-Print Network (OSTI)

by the chemical researchers at CFE, A. Manon M. , J. Faustodata was generated by the CFE Laboratory at Cerro Prieto andThe staff of the IIE and CFE laboratories at Cerro Prieto

Weres, O.

2012-01-01T23:59:59.000Z

479

Chemistry of Silica in Cerro Prieto Brines  

E-Print Network (OSTI)

data was generated by t e CFE Laioratory a t Cerro Prietowere performed a t the CFE Laboratory a t Cerro P r i e t oe h e l p of J,. Fausto L of CFE. Brine from Cerro P r i e t

Weres, O.

2010-01-01T23:59:59.000Z

480

Geothermometry At Lassen Volcanic National Park Area (Janik ...  

Open Energy Info (EERE)

but are within the 220-240 degrees C range calculated using cation, sulfate-water isotope, and mixing model geothermometers (Muffler et al., 1982). References (Unknown)...

Note: This page contains sample records for the topic "multicomponent geothermometers silica" from the National Library of EnergyBeta (NLEBeta).
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481

Chemistry of the Silica Surface:? Liquid?Solid Reactions of Silica Gel with Trimethylaluminum  

Science Journals Connector (OSTI)

(36)?Uusitalo, A. M.; Pakkanen, T. T.; Kroger-Laukkanen, M.; Niinisto, L.; Hakala, K.; Paavola, S.; Lofgren, B. J. Mol. ... Uusitalo, A.-M.; Pakkanen, T. T.; Kroger-Laukkanen, M.; Niinisto, L.; Hakala, K.; Paavola, S.; Lofgren, B. ...

Jianhua Li; Joseph A. DiVerdi; Gary E. Maciel

2006-12-07T23:59:59.000Z

482

Fermionic construction of partition function for multi-matrix models and multi-component TL hierarchy  

E-Print Network (OSTI)

We use $p$-component fermions $(p=2,3,...)$ to present $(2p-2)N$-fold integrals as a fermionic expectation value. This yields fermionic representation for various $(2p-2)$-matrix models. Links with the $p$-component KP hierarchy and also with the $p$-component TL hierarchy are discussed. We sh