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1

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

2

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

3

Cellular membrane trafficking of mesoporous silica nanoparticles  

Science Conference Proceedings (OSTI)

This dissertation mainly focuses on the investigation of the cellular membrane trafficking of mesoporous silica nanoparticles. We are interested in the study of endocytosis and exocytosis behaviors of mesoporous silica nanoparticles with desired surface functionality. The relationship between mesoporous silica nanoparticles and membrane trafficking of cells, either cancerous cells or normal cells was examined. Since mesoporous silica nanoparticles were applied in many drug delivery cases, the endocytotic efficiency of mesoporous silica nanoparticles needs to be investigated in more details in order to design the cellular drug delivery system in the controlled way. It is well known that cells can engulf some molecules outside of the cells through a receptor-ligand associated endocytosis. We are interested to determine if those biomolecules binding to cell surface receptors can be utilized on mesoporous silica nanoparticle materials to improve the uptake efficiency or govern the mechanism of endocytosis of mesoporous silica nanoparticles. Arginine-glycine-aspartate (RGD) is a small peptide recognized by cell integrin receptors and it was reported that avidin internalization was highly promoted by tumor lectin. Both RGD and avidin were linked to the surface of mesoporous silica nanoparticle materials to investigate the effect of receptor-associated biomolecule on cellular endocytosis efficiency. The effect of ligand types, ligand conformation and ligand density were discussed in Chapter 2 and 3. Furthermore, the exocytosis of mesoporous silica nanoparticles is very attractive for biological applications. The cellular protein sequestration study of mesoporous silica nanoparticles was examined for further information of the intracellular pathway of endocytosed mesoporous silica nanoparticle materials. The surface functionality of mesoporous silica nanoparticle materials demonstrated selectivity among the materials and cancer and normal cell lines. We aimed to determine the specific organelle that mesoporous silica nanoparticles could approach via the identification of harvested proteins from exocytosis process. Based on the study of endo- and exocytosis behavior of mesoporous silica nanoparticle materials, we can design smarter drug delivery vehicles for cancer therapy that can be effectively controlled. The destination, uptake efficiency and the cellular distribution of mesoporous silica nanoparticle materials can be programmable. As a result, release mechanism and release rate of drug delivery systems can be a well-controlled process. The deep investigation of an endo- and exocytosis study of mesoporous silica nanoparticle materials promotes the development of drug delivery applications.

Fang, I-Ju

2012-06-21T23:59:59.000Z

4

Mesoporous Silica-Supported Rhodium Nanocatalysts for Selective...  

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

Mesoporous Silica-Supported Rhodium Nanocatalysts for Selective Production of Ethanol From Syngas and Conversion of Ethanol to Hydrogen Description Coal will likely play a major...

5

(129)Xe NMR of Mesoporous Silicas  

DOE Green Energy (OSTI)

The porosities of three mesoporous silica materials were characterized with {sup 129}Xe NMR spectroscopy. The materials were synthesized by a sol-gel process with r = 0, 25, and 70% methanol by weight in an aqueous cetyltrimethylammonium bromide solution. Temperature dependent chemical shifts and spin lattice relaxation times reveal that xenon does not penetrate the pores of the largely disordered (r= 70%) silica. For both r = 0 and 25%, temperature dependent resonances corresponding to physisorbed xenon were observed. An additional resonance for the r = 25% sample was attributed to xenon between the disordered cylindrical pores. 2D NMR exchange experiments corroborate the spin lattice relaxation data which show that xenon is in rapid exchange between the adsorbed and the gas phase.

Anderson, M.T.; Asink, R.A.; Kneller, J.M.; Pietrass, T.

1999-04-23T23:59:59.000Z

6

Functionalized bimodal mesoporous silicas as carriers for controlled aspirin delivery  

Science Conference Proceedings (OSTI)

The bimodal mesoporous silica modified with 3-aminopropyltriethoxysilane was performed as the aspirin carrier. The samples' structure, drug loading and release profiles were characterized with X-ray diffraction, scanning electron microscopy, N{sub 2} adsorption and desorption, Fourier transform infrared spectroscopy, TG analysis, elemental analysis and UV-spectrophotometer. For further exploring the effects of the bimodal mesopores on the drug delivery behavior, the unimodal mesoporous material MCM-41 was also modified as the aspirin carrier. Meantime, Korsmeyer-Peppas equation f{sub t}=kt{sup n} was employed to analyze the dissolution data in details. It is indicated that the bimodal mesopores are beneficial for unrestricted drug molecules diffusing and therefore lead to a higher loading and faster releasing than that of MCM-41. The results show that the aspirin delivery properties are influenced considerably by the mesoporous matrix, whereas the large pore of bimodal mesoporous silica is the key point for the improved controlled-release properties. - Graphical abstract: Loading (A) and release profiles (B) of aspirin in N-BMMs and N-MCM-41 indicated that BMMs have more drug loading capacity and faster release rate than that MCM-41. Highlights: > Bimodal mesoporous silicas (BMMs) and MCM-41 modified with amino group via post-treatment procedure. > Loading and release profiles of aspirin in modified BMMs and MCM-41. > Modified BMMs have more drug loading capacity and faster release rate than that modified MCM-41.

Gao Lin [Department of Chemistry and Chemical Engineering, College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124 (China); Sun Jihong, E-mail: jhsun@bjut.edu.cn [Department of Chemistry and Chemical Engineering, College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124 (China); Li Yuzhen [Department of Chemistry and Chemical Engineering, College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124 (China)

2011-08-15T23:59:59.000Z

7

Controlled drug release from bifunctionalized mesoporous silica  

Science Conference Proceedings (OSTI)

Serial of trimethylsilyl-carboxyl bifunctionalized SBA-15 (TMS/COOH/SBA-15) have been studied as carriers for controlled release of drug famotidine (Famo). To load Famo with large capacity, SBA-15 with high content of carboxyl groups was successfully synthesized by one-pot synthesis under the assistance of KCl. The mesostructure of carboxyl functionalized SBA-15 (COOH/SBA-15) could still be kept even though the content of carboxyl groups was up to 57.2%. Increasing carboxyl content could effectively enhance the loading capacity of Famo. Compared with pure SBA-15, into which Famo could be hardly adsorbed, the largest drug loading capacity of COOH/SBA-15 could achieve 396.9 mg/g. The release of Famo from mesoporous silica was studied in simulated intestine fluid (SIF, pH=7.4). For COOH/SBA-15, the release rate of Famo decreased with narrowing pore size. After grafting TMS groups on the surface of COOH/SBA-15 with hexamethyldisilazane, the release of Famo was greatly delayed with the increasing content of TMS groups. - Graphical abstract: Trimethylsilyl-carboxyl bifunctionalized SBA-15 has been studied as carrier for controlled release of drug famotidine. To load drug with large capacity, SBA-15 with high content of carboxyl groups was successfully synthesized. After grafting trimethylsilyl groups on the surface of carboxyl functionalized SBA-15, the release of Famo was greatly delayed with the increasing content of TMS groups.

Xu Wujun; Gao Qiang [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China); Graduate University of the Chinese Academy of Sciences, Beijing 100049 (China); Xu Yao [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China)], E-mail: xuyao@sxicc.ac.cn; Wu Dong; Sun Yuhan [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China); Shen Wanling [State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China); Graduate University of the Chinese Academy of Sciences, Beijing 100049 (China); Deng Feng [State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China)

2008-10-15T23:59:59.000Z

8

Mesoporous-silica films, fibers, and powders by evaporation  

SciTech Connect

This invention pertains to surfactant-templated nanometer-scale porosity of a silica precursor solution and forming a mesoporous material by first forming the silica precursor solution into a preform having a high surface area to volume ratio, then rapid drying or evaporating a solvent from the silica precursor solution. The mesoporous material may be in any geometric form, but is preferably in the form of a film, fiber, powder or combinations thereof. The rapid drying or evaporation of solvent from the solution is accomplished by layer thinning, for example spin casting, liquid drawing, and liquid spraying respectively. Production of a film is by layer thinning, wherein a layer of the silica precursor solution is formed on a surface followed by removal of an amount of the silica precursor solution and leaving a geometrically thinner layer of the silica precursor solution from which the solvent quickly escapes via evaporation. Layer thinning may be by any method including but not limited to squeegeeing and/or spin casting. In powder formation by spray drying, the same conditions of fast drying exists as in spin-casting (as well as in fiber spinning) because of the high surface-area to volume ratio of the product. When a powder is produced by liquid spraying, the particles or micro-bubbles within the powder are hollow spheres with walls composed of mesoporous silica. Mesoporous fiber formation starts with a similar silica precursor solution but with an added pre-polymer making a pituitous mixture that is drawn into a thin strand from which solvent is evaporated leaving the mesoporous fiber(s).

Bruinsma, Paul J. (Kennewick, WA); Baskaran, Suresh (Kennewick, WA); Bontha, Jagannadha R. (Richland, WA); Liu, Jun (West Richland, WA)

1999-01-01T23:59:59.000Z

9

Carbon nanomaterials in silica aerogel matrices  

SciTech Connect

Silica aerogels are ultra low-density, high surface area materials that are extremely good thermal insulators and have numerous technical applications. However, their mechanical properties are not ideal, as they are brittle and prone to shattering. Conversely, single-walled carbon nanotubes (SWCNTs) and graphene-based materials, such as graphene oxide, have extremely high tensile strength and possess novel electronic properties. By introducing SWCNTs or graphene-based materials into aerogel matrices, it is possible to produce composites with the desirable properties of both constituents. We have successfully dispersed SWCNTs and graphene-based materials into silica gels. Subsequent supercritical drying results in monolithic low-density composites having improved mechanical properties. These nanocomposite aerogels have great potential for use in a wide range of applications.

Hamilton, Christopher E [Los Alamos National Laboratory; Chavez, Manuel E [Los Alamos National Laboratory; Duque, Juan G [Los Alamos National Laboratory; Gupta, Gautam [Los Alamos National Laboratory; Doorn, Stephen K [Los Alamos National Laboratory; Dattelbaum, Andrew M [Los Alamos National Laboratory; Obrey, Kimberly A D [Los Alamos National Laboratory

2010-01-01T23:59:59.000Z

10

Plutonium complexation by phosphonate-functionalized mesoporous silica  

Science Conference Proceedings (OSTI)

MCM-41-type mesoporous silica functionalized with the CMPO-based 'Ac-Phos' silane has been reported in the literature (1) to show good capacity as an acftinide sorbent material, with potential applications in environmental sequestration, aqueous waste separation and/or vitrification, and chemical sensing of actinides in solution. The study explores the complexation of Pu(IV and VI) and other selected actinides and lanthanides by SBA-15 type mesoporous silica functionalized with Ac-Phos. The Pu binding kinetics and binding capacity were determined for both the Ac-Phos functionalized and unmodified SBA-15. They analyzed the binding geometry and redox behavior of Pu(VI) by X-ray absorption spectroscopy (XAS). They discuss the synthesis and characterization of the functionalized mesoporous material, batch sorption experiments, and the detailed analyses of the actinide complexes that are formed. Structural measurements are paired with high-level quantum mechanical modeling to elucidate the binding mechanisms.

Parsons-Moss, T; Schwaiger, L K; Hubaud, A; Hu, Y J; Tuysuz, H; Yang, P; Balasubramanian, K; Nitsche, H

2010-10-27T23:59:59.000Z

11

Fluorescent Functionalized Mesoporous Silica for Radioactive Material Extraction  

Science Conference Proceedings (OSTI)

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

12

Luminescence properties of mesoporous silica nanoparticles encapsulating different europium complexes: application for biolabelling  

Science Conference Proceedings (OSTI)

In this work we have synthesized and characterized new hybrid nanoplatforms for luminescent biolabeling based on the concept of Eu3+ complexes encapsulation in mesoporous silica nanoparticles (?100 nm). Eu complexes have been selected ...

S. Lechevallier, J. Jorge, R. M. Silveira, N. Ratel-Ramond, D. Neumeyer, M. J. Menu, M. Gressier, A. L. Marçal, A. L. Rocha, M. A. U. Martines, E. Magdeleine, J. Dexpert-Ghys, M. Verelst

2013-01-01T23:59:59.000Z

13

Mesoporous silica SBA-16 functionalized with alkoxysilane groups: preparation, characterization, and release profile study  

Science Conference Proceedings (OSTI)

A mesoporous material sphere based on silica, SBA-16, was chemically modified with alkoxysilane using two different solvents: methanol and toluene. The influence of the chemical modification of the matrix on the release rate of a model drug was also ...

Gracielle Ferreira Andrade; Daniel Cristian Ferreira Soares; Ramon Kenned de Sousa Almeida; Edésia Martins Barros Sousa

2012-01-01T23:59:59.000Z

14

Mesoporous silica film from a solution containing a surfactant and methods of making same  

DOE Patents (OSTI)

The present invention is a mesoporous silica film having a low dielectric constant and method of making having the steps of combining a surfactant in a silica precursor solution, spin-coating a film from this solution mixture, forming a partially hydroxylated mesoporous film, and dehydroxylating the hydroxylated film to obtain the mesoporous film. It is advantageous that the small polyoxyethylene ether surfactants used in spin-coated films as described in the present invention will result in fine pores smaller on average than about 20 nm. The resulting mesoporous film has a dielectric constant less than 3, which is stable in moist air with a specific humidity. The present invention provides a method for superior control of film thickness and thickness uniformity over a coated wafer, and films with low dielectric constant.

Liu, Jun (West Richland, WA); Domansky, Karel (Cambridge, MA); Li, Xiaohong (Richland, WA); Fryxell, Glen E. (Kennewick, WA); Baskaran, Suresh (Kennewick, WA); Kohler, Nathan J. (Richland, WA); Thevuthasan, Suntharampillai (Kennewick, WA); Coyle, Christopher A. (Richland, WA); Birnbaum, Jerome C. (Richland, WA)

2001-01-01T23:59:59.000Z

15

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

16

Highly ordered Zn-doped mesoporous silica: An efficient catalyst for transesterification reaction  

Science Conference Proceedings (OSTI)

Designing highly ordered material with nanoscale periodicity is of great significance in the field of solid state chemistry. Herein, we report the synthesis of highly ordered 2D-hexagonal mesoporous zinc-doped silica using a mixture of anionic and cationic surfactants under hydrothermal conditions. Powder XRD, N{sub 2} sorption, TEM analysis revealed highly ordered 2D-hexagonal arrangements of the pores with very good surface area (762 m{sup 2} g{sup -1}) in this Zn-rich mesoporous material. Chemical analysis shows very high loading of zinc (ca. 12.0 wt%) in the material together with retention of hexagonal pore structure. Interestingly, high temperature calcination resulted into zinc silicate phase, unlike any ZnO phase, which otherwise is expected under heat treatments. High surface area together with Zn loading in this mesoporous material has been found useful for the catalytic activity of the materials in the acid-catalyzed transesterification reactions of various esters under mild liquid phase conditions. - Graphical abstract: Zn-rich 2D-hexagonal mesoporous materials are synthesized hydrothermally, which show very good catalytic activity in the transesterification reaction under mild liquid phase reaction conditions. Highlights: > Zn-rich 2D-hexagonal mesoporous silica. > High surface area material. > Efficient catalyst in liquid phase transesterification reaction. > Biodiesel production.

Pal, Nabanita; Paul, Manidipa [Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India); Bhaumik, Asim, E-mail: msab@iacs.res.in [Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India)

2011-07-15T23:59:59.000Z

17

Thermal Conductivity of Cubic and Hexagonal Mesoporous Silica Thin Films  

E-Print Network (OSTI)

K.L. Fang, “Anisotropic thermal conductivity of nanoporousmesoporous silica as a thermal isolation layer”, Ceramicsand V. Wittwer, “Some thermal and optical properties of a

Coquil, Thomas; Richman, Eric K.; Hutchinson, Neal J.; Tolbert, S H; Pilon, Laurent

2009-01-01T23:59:59.000Z

18

Highly ordered magnetic mesoporous silicas for effective elimination of carbon monoxide  

Science Conference Proceedings (OSTI)

Catalysts based on crystalline nanoparticles of Fe metal supported on mesoporous silica have been developed. The synthetic process involves hydrogen reduction processing for high abundant Fe metal nanoparticles within the mesopores, in which impregnated Fe salt in the inner nanopores of mesoporous silica is thermally treated under hydrogen at 500 Degree-Sign C. Detailed characterization was achieved by XRD, XPS, BET, and HR-TEM techniques. The catalytic efficiency was demonstrated as a function of the used amounts and reaction time. The results show that more than 90% of the carbon monoxide was eliminated at room temperature during a period 80 min with 0.5 g of catalyst. - Graphical abstract: Strategy for the preparation of highly abundant Fe nanoparticle embedded MS catalyst by hydrogen reduction process and HR-TEM images of cross-sectional and top view. Highlights: Black-Right-Pointing-Pointer MS based heterogeneous catalyst with Fe nanoparticles were demonstrated for CO elimination. Black-Right-Pointing-Pointer Highly Fe nanoparticle embedded MS catalyst prepared by hydrogen reduction process. Black-Right-Pointing-Pointer Systematic characterization was achieved by XRD, XPS, BET, and HR-TEM analyses. Black-Right-Pointing-Pointer More than 90% of the CO was eliminated at RT during 80 min with 0.5 g of catalyst.

Lee, Jiho [Korea Institute of Ceramic Engineering and Technology, Seoul 153-801 (Korea, Republic of); Department of Chemistry, Inha University, Incheon 402-751 (Korea, Republic of); Ho Chang, Jeong, E-mail: jhchang@kicet.re.kr [Korea Institute of Ceramic Engineering and Technology, Seoul 153-801 (Korea, Republic of)

2012-04-15T23:59:59.000Z

19

Self-Assembled Mercaptan on Mesoporous Silica (SAMMS) technology of mercury removal and stabilization  

SciTech Connect

This paper explains the technology developed to produce Self-Assembled Mercaptan on Mesoporous Silica (SAMMS) for mercury removal from aqueous wastewater and from organic wastes. The characteristics of SAMMS materials, including physical characteristics and mercury loading, and its application for mercury removal and stabilization are discussed. Binding kinetics and binding speciations are reported. Preliminary cost estimates are provided for producing SAMMS materials and for mercury removal from wastewater. The characteristics of SAMMS in mercury separation were studied at PNNL using simulated aqueous tank wastes and actual tritiated pump oil wastes from Savannah River Site; preliminary results are outlined. 47 refs., 16 figs., 16 tabs.

Feng, Xiangdong; Liu, Jun; Fryxell, G.E. [and others

1997-09-01T23:59:59.000Z

20

Silver nanoparticles confined in SBA-15 mesoporous silica and the application as a sensor for detecting hydrogen peroxide  

Science Conference Proceedings (OSTI)

Silver nanoparticles within the pore channels of selectively grafted mesoporous silica SBA-15 were synthesized. Silanols on the external surface of as-SBA-15 were first capped by -Si(CH3)3 groups. After removal of the template of ...

Dong-Hai Lin; Yan-Xia Jiang; Ying Wang; Shi-Gang Sun

2008-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "mesoporous silica nanomaterials" 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

Enzymatic Conversion of CO2 to Bicarbonate in Functionalized Mesoporous Silica  

Science Conference Proceedings (OSTI)

We report here that carbonic anhydrase (CA), the fastest enzyme that can covert carbon dioxide to bicarbonate, can be spontaneously entrapped in functionalized mesoporous silica (FMS) with super-high loading density (up to 0.5 mg of protein/mg of FMS) due to the dominant electrostatic interaction. The binding of CA to HOOC-FMS can result in the protein’s conformational change comparing to the enzyme free in solution, but can be overcome with increased protein loading density. The higher the protein loading density, the less conformational change, hence the higher enzymatic activity and the higher enzyme immobilization efficiency. The electrostatically bound CA can be released by changing pH. The released enzyme still displayed the native conformational structure and the same high enzymatic activity as that prior to the enzyme entrapment. This work opens up a new approach converting carbon dioxide to biocarbonate in a biomimetic nanoconfiguration that can be integrated with the other part of biosynthesis process for the assimilation of carbon dioxide.

Yu, Yuehua; Chen, Baowei; Qi, Wen N.; Li, Xiaolin; Shin, Yongsoon; Lei, Chenghong; Liu, Jun

2012-05-01T23:59:59.000Z

22

Robust conductive mesoporous carbon?silica composite films with highly ordered and oriented orthorhombic structures from triblock-copolymer template co-assembly  

Science Conference Proceedings (OSTI)

In this work, we describe a facile approach to improve the robustness of conductive mesoporous carbon-based thin films by the addition of silica to the matrix through the triconstituent organic-inorganic-organic co-assembly of resol (carbon precursor) and tetraethylorthosilicate (silica precursor) with triblock-copolymer Pluronic F127. The pyrolysis of the resol-silica-pluronic F127 film yields a porous composite thin film with well-defined mesostructure. X-Ray diffraction (XRD), grazing incidence small angle X-ray scattering (GISAXS), and electron microscopy measurements indicate that the obtained carbon-based thin films have a highly ordered orthorhombic mesostructure (Fmmm) with uniform large pore size ({approx}3 nm). The orthorhombic mesostructure is oriented and the (010) plane is parallel to the silicon wafer substrate. The addition of silica to the matrix impacts the pore size, surface area, porosity, modulus and conductivity. For composite films with approximately 40 wt% silica, the conductivity is decreased by approximately an order of magnitude in comparison to a pure carbon mesoporous film, but the conductivity is comparable to typical printed carbon inks used in electrochemical sensing, {approx}10 S cm{sup -1}. The mechanical properties of these mesoporous silica-carbon hybrid films are similar to the pure carbon analogs with a Young's modulus between 10 GPa and 15 GPa, but the material is significantly more porous. Moreover, the addition of silica to the matrix appears to improve the adhesion of the mesoporous film to a silicon wafer. These mesoporous silica-carbon composite films have appropriate characteristics for use in sensing applications.

Song, Lingyan; Feng, Dan; Campbell, Casey G.; Gu, Dong; Forster, Aaron M.; Yager, Kevin G.; Fredin, Nathaniel; Lee, Hae-Jeong; Jones, Ronald L.; Zhao, Dongyuan; Vogt, Bryan D. (AZU)

2012-07-11T23:59:59.000Z

23

Pore size effects on the sorption of supercritical carbon dioxide in mesoporous CPG-10 silica  

Science Conference Proceedings (OSTI)

Excess sorption isotherms of supercritical carbon dioxide in mesoporous CPG-10 silica glasses with nominal pore sizes of 75 (7.5 nm) and 350 (35 nm) were measured gravimetrically at 35 C and 50 C and pressures of 0-200 bar. Formation of broad maxima in the excess sorption was observed at fluid densities below the bulk critical density. Positive values of excess sorption were measured at bulk densities below about 0.65-0.7 g/cm3, whereas zero and negative values were obtained at higher densities, indicating that the interfacial fluid becomes less dense than the corresponding bulk fluid at high fluid densities. A shift of the excess sorption peak position to higher fluid density is found with increasing pore width. The excess sorption of CO2 normalized to the specific surface area is higher for the 35 nm pore size material, suggesting pore confinement effects. Conversely, the pore volume normalized excess sorption is higher for the 7.5 nm pore size material. Assessment of mean pore density reveals regions of constant pore fluid density, located between the excess sorption peak and the adsorption/depletion transition. Both materials exhibit such regions of constant mean pore fluid density as a function of bulk CO2 density at the lower temperature of 35 C, but not at 50 C. The results of this study suggest that the CO2 storage capacity in quartz-rich reservoirs is higher for sites with low temperature and rock textures characterized by narrow pores with high surface to volume ratios.

Rother, Gernot [ORNL; Krukowski, Elizabeth G [ORNL; Wallacher, Dirk [Helmholtz-Zentrum Berlin; Grimm, Nico [Helmholtz-Zentrum Berlin; Bodnar, Robert J [ORNL; Cole, David [Ohio State University

2012-01-01T23:59:59.000Z

24

Drug delivery from hydrophobic-modified mesoporous silicas: Control via modification level and site-selective modification  

SciTech Connect

Dimethylsilyl (DMS) modified mesoporous silicas were successfully prepared via co-condensation and post-grafting modification methods. The post-grafting modification was carried out by the reaction of the as-synthesized MCM-41 material (before CTAB removal) with diethoxydimethylsinale (DEDMS). N{sub 2} adsorption-desorption and {sup 29}Si MAS NMR characterization demonstrated that different amount of DMS groups were successfully incorporated into the co-condensation modified samples, and the functional DMS groups were placed selectively on the pore openings and external pore surfaces in the post-grafting modified samples. Subsequently, the controlled drug delivery properties from the resulting DMS-modified mesoporous silicas were investigated in detail. The drug adsorption experiments showed that the adsorption capacities were mainly depended on the content of silanol group (CSG) in the corresponding carriers. The in vitro tests exhibited that the incorporation of DMS groups greatly retarded the ibuprofen release rate. Moreover, the ibuprofen release profiles could be well modulated by varying DMS modification levels and site-selective distribution of functional groups in mesoporous carriers. - The distribution of DMS groups on the pore surfaces of the mesostructures strongly affects the drug release rate. The P-M41-1 and the P-M41-2 possess the close DMS modification levels as the C-M41-10, but the ibuprofen release rates from the P-M41-1 and P-M41-2 are much slower than that from the C-M41-10.

Tang Qunli, E-mail: tangqunli@hnu.c [College of Materials Science and Engineering, and Center for High-Resolution Electron Microscopy, Hunan University, Changsha 410082 (China); State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China); Chen Yuxi; Chen Jianghua; Li Jin [College of Materials Science and Engineering, and Center for High-Resolution Electron Microscopy, Hunan University, Changsha 410082 (China); Xu Yao; Wu Dong; Sun Yuhan [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China)

2010-01-15T23:59:59.000Z

25

Mesoporous Silica Nanoparticles Loaded with Surfactant: Low Temperature Magic Angle Spinning 13C and 29Si NMR Enhanced by Dynamic Nuclear Polarization  

SciTech Connect

We show that dynamic nuclear polarization (DNP) can be used to enhance NMR signals of 13C and 29Si nuclei located in mesoporous organic/inorganic hybrid materials, at several hundreds of nanometers from stable radicals (TOTAPOL) trapped in the surrounding frozen disordered water. The approach is demonstrated using mesoporous silica nanoparticles (MSN), functionalized with 3-(N-phenylureido)propyl (PUP) groups, filled with the surfactant cetyltrimethylammonium bromide (CTAB). The DNP-enhanced proton magnetization is transported into the mesopores via 1H–1H spin diffusion and transferred to rare spins by cross-polarization, yielding signal enhancements ?on/off of around 8. When the CTAB molecules are extracted, so that the radicals can enter the mesopores, the enhancements increase to ?on/off ? 30 for both nuclei. A quantitative analysis of the signal enhancements in MSN with and without surfactant is based on a one-dimensional proton spin diffusion model. The effect of solvent deuteration is also investigated.

Lafon, Olivier [Universite de Lille Nord de France; Thankamony, Aany S. Lilly [Universite de Lille Nord de France; Kokayashi, Takeshi [Ames Laboratory; Carnevale, Diego [Ecole Polytechnique Federale de Lausanne; Vitzthum, Veronika [Ecole Polytechnique Federale de Lausanne; Slowing, Igor I. [Ames Laboratory; Kandel, Kapil [Ames Laboratory; Vezin, Herve [Universite de Lille Nord de France; Amoureux, Jean-Paul [Universite de Lille Nord de France; Bodenhausen, Geoffrey [Ecole Polytechnique Federale de Lausanne; Pruski, Marek [Ames Laboratory

2012-12-21T23:59:59.000Z

26

Mesoporous Silica with Site-Isolated Amine and Phosphotungstic Acid Groups: A Solid Catalyst with Tunable Antagonistic Functions for One-Pot Tandem Reactions  

Science Conference Proceedings (OSTI)

A bifunctional solid catalyst is prepared by combining acid and base functions on mesoporous silica supports. The co-existence of these functions is shown by a two-step reaction sequence in one pot. Excellent product yields, which cannot be obtained by separated acid and base functions in one pot, show the validity of our concept.

Shiju N. R.; Syed K.; Alberts A.; Brown D. and Rothenberg G.

2011-09-15T23:59:59.000Z

27

Formation of mesoporous materials from silica dissolved in various NaOH concentrations: effect of pH and ionic strength  

Science Conference Proceedings (OSTI)

We describe the effects of NaOH/SiO2 ratio and pH on the formation of mesoporous materials, which was synthesized via an alkalimetal hydroxide fusion method, from amorphous silica dissolved in NaOH. Physical properties (e.g., specific surface ...

Jayhyun Park; Yosep Han; Hyunjung Kim

2012-01-01T23:59:59.000Z

28

Synthesis of attrition-resistant heterogeneous catalysts using templated mesoporous silica  

DOE Patents (OSTI)

The present invention relates to catalysts in mesoporous structures. In a preferred embodiment, the invention comprises a method for encapsulating a dispersed insoluble compound in a mesoporous structure comprising combining a soluble oxide precursor, a solvent, and a surfactant to form a mixture; dispersing an insoluble compound in the mixture; spray-drying the mixture to produce dry powder; and calcining the powder to yield a porous structure comprising the dispersed insoluble compound.

Pham, Hien N. (Albuquerque, NM); Datye, Abhaya K. (Albuquerque, NM)

2003-04-15T23:59:59.000Z

29

Cr(VI) adsorption on functionalized amorphous and mesoporous silica from aqueous and non-aqueous media  

Science Conference Proceedings (OSTI)

A mesoporous silica (SBA-15) and amorphous silica (SG) have been chemically modified with 2-mercaptopyridine using the homogeneous route. This synthetic route involved the reaction of 2-mercaptopyridine with 3-chloropropyltriethoxysilane prior to immobilization on the support. The resulting material has been characterized by powder X-ray diffraction, nitrogen gas sorption, FT-IR and MAS NMR spectroscopy, thermogravimetry and elemental analysis. The solid was employed as a Cr(VI) adsorbent from aqueous and non-aqueous solutions at room temperature. The effect of several variables (stirring time, pH, metal concentration and solvent polarity) has been studied using the batch technique. The results indicate that under the optimum conditions, the maximum adsorption value for Cr(VI) was 1.83 {+-} 0.03 mmol/g for MP-SBA-15, whereas the adsorption capacity of the MP-SG was 0.86 {+-} 0.02 mmol/g. On the basis of these results, it can be concluded that it is possible to modify chemically SBA-15 and SG with 2-mercaptopyridine and to use the resulting modified silicas as effective adsorbents for Cr(VI)

Perez-Quintanilla, Damian [Departamento de Quimica Inorganica y Analitica, E.S.C.E.T, Universidad Rey Juan Carlos, C/Tulipan s/n, 28933 Mostoles, Madrid (Spain)]. E-mail: damian.perez@urjc.es; Hierro, Isabel del [Departamento de Quimica Inorganica y Analitica, E.S.C.E.T, Universidad Rey Juan Carlos, C/Tulipan s/n, 28933 Mostoles, Madrid (Spain); Fajardo, Mariano [Departamento de Quimica Inorganica y Analitica, E.S.C.E.T, Universidad Rey Juan Carlos, C/Tulipan s/n, 28933 Mostoles, Madrid (Spain); Sierra, Isabel [Departamento de Quimica Inorganica y Analitica, E.S.C.E.T, Universidad Rey Juan Carlos, C/Tulipan s/n, 28933 Mostoles, Madrid (Spain)]. E-mail: isabel.sierra@urjc.es

2007-08-07T23:59:59.000Z

30

Carbon Nanomaterials II & Computational Studies on Nanomaterials  

Science Conference Proceedings (OSTI)

2014 Functional Nanomaterials: Synthesis, Properties and Applications: Carbon Nanomaterials II & Computational Studies on Nanomaterials Sponsored by: ...

31

Visible Light Absorption of Binuclear TiOCoII Charge-Transfer UnitAssembled in Mesoporous Silica  

SciTech Connect

Grafting of CoII(NCCH3)2Cl2 onto mesoporous Ti-MCM-41 silicain acetonitrile solution affords binuclear Ti-O-CoII sites on the poresurface under complete replacement of the precursor ligands byinteractions with anchored Ti centers and the silica surface. The CoIIligand field spectrum signals that the Co centers are anchored on thepore surface in tetrahedral coordination. FT-infrared action spectroscopyusing ammonia gas adsorption reveals Co-O-Si bond modes at 831 and 762cm-1. No Co oxide clusters are observed in the as-synthesized material.The bimetallic moieties feature an absorption extending from the UV intothe visible to about 600 nm which is attributed to the TiIV-O-CoII?3TiIII-O-CoIII metal-to-metal charge-transfer (MMCT) transition. Thechromophore is absent in MCM-41 containing Ti and Co centers isolatedfrom each other; this material was synthesized by grafting CoII onto aTi-MCM-41 sample with the Ti centers protected by a cyclopentadienylligand. The result indicates that the appearance of the charge-transferabsorption requires that the metal centers are linked by an oxo bridge,which is additionally supported by XANES spectroscopy. The MMCTchromophore of Ti-O-CoII units has sufficient oxidation power to serve asvisible light electron pump for driving multi-electron transfer catalystsof demanding uphill reactions such as water oxidation.

Han, Hongxian; Frei, Heinz

2007-01-30T23:59:59.000Z

32

Dynamics of Propane in Silica Mesopores Formed upon PropyleneHydrogenation over Pt Nanoparticles by Time-Resolved FT-IRSpectroscopy  

DOE Green Energy (OSTI)

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

33

Nanomaterials: General  

Science Conference Proceedings (OSTI)

Feb 28, 2011... ideas, and instrumentation primarily through awards to the nation's ... Nanomaterials Control for Biotech Applications: Sungho Jin1; 1UC San ...

34

Synthesis of sulfated titania supported on mesoporous silica using direct impregnation and its application in esterification of acetic acid and n-butanol  

SciTech Connect

A new method has been developed for the preparation of sulfated titania (S-TiO{sub 2}) supported on mesoporous silica. The use of direct exchange of metal containing precursors for the surfactants in the as-synthesized MCM-41 substrate produced a product with high sulfur content without serious blockage of the pore structure of MCM-41. The pore sizes and volumes of the resultant S-TiO{sub 2}/MCM-41 composites were found to vary markedly with the loading of TiO{sub 2}. The strong acidic character of the composites obtained was examined by using them as catalysts for the esterification of acetic acid and n-butanol. - Abstract: XRD profiles of the composites of S-TiO{sub 2}/MCM-41 with different TiO{sub 2} contents. The low angle peaks indicate the MCM-41-like structure retained and a TiO{sub 2} phase appeared at high angle region. Display Omitted

Wang Yuhong, E-mail: yuhong_wang502@sit.edu.c [Research Institute of Applied Catalysis, School of Chemical and Environmental Engineering, Shanghai Institute of Technology, Shanghai 200235 (China); Gan Yunting [Research Institute of Applied Catalysis, School of Chemical and Environmental Engineering, Shanghai Institute of Technology, Shanghai 200235 (China); Whiting, Roger [School of Applied Science, Faculty of Health and Environmental Sciences, Auckland University of Technology, Auckland (New Zealand); Lu Guanzhong [Research Institute of Applied Catalysis, School of Chemical and Environmental Engineering, Shanghai Institute of Technology, Shanghai 200235 (China)

2009-09-15T23:59:59.000Z

35

Mesoporous Silica-Supported Metal Oxide-Promoted Rh Nanocatalyst for Selective Production of Ethanol from Syngas  

DOE Green Energy (OSTI)

The objective is to develop a process that will convert synthesis gas from coal into ethanol and then transform the ethanol into hydrogen. Principal investigators from Iowa State University include Dr. George Kraus, Dr. Victor Lin, Marek Pruski, and Dr. Robert Brown. Task 1 involves catalyst development and catalyst scale up. Mesoporous manganese silicate mixed oxide materials will be synthesized, characterized and evaluated. The first-and secondgeneration catalysts have been prepared and scaled up for use in Task 2. The construction of a high-pressure reactor system for producing synthetic liquid fuel from simulated synthesis gas stream has been completed as the first step in Task 2. Using the first- and second generation catalysts, the reactor has demonstrated the production of synthetic liquid fuel from a simulated synthesis gas stream.

George Kraus

2010-09-30T23:59:59.000Z

36

Nanomaterials Chemistry Group - CSD  

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

CSD CSD Organization Contact List Search Other Links CSD CSD Organization Contact List Search Other Links Selected Research and Development Projects The Nanomaterials Chemistry Group at Chemical Sciences Division, the Oak Ridge National Laboratory conducts fundamental research related to synthesis and characterization of nanoscopic materials as well as ionic liquids for fundamental investigation of separation and catalysis processes. This group also conducts the applied research related to the applications of nanomaterials in advanced scintillators for radiation sensing, catalysts for fuel cells, radioactive tracers for medical imaging, novel electrodes for energy storage, and sensing devices for biological agents. Extensive synthesis capabilities exist within the group for preparation of mesoporous materials (oxides and carbons), low-dimensional materials (e.g., quantum dots and nanowires), sol-gel materials, inorganic and hybrid monoliths (e.g., membranes), and nanocatalysts. Solvothermal, ionothermal, templating synthesis, chemical vapor deposition (CVD), and atomic layer deposition (ALD) methods are extensively utilized in the group for tailored synthesis of nanostructured materials. An array of techniques for characterizing physical and chemical properties related to separation and catalysis are in place or are currently being developed. This research program also takes advantage of the unique resources at ORNL such as small-angle x-ray scattering, small-angle neutron scattering at the High Flux Isotope Reactor and Spallation Neutron Source (SNS), structural analysis by a variety of electron microscopes (SEM, TEM, STEM, HRTEM) and powdered X-ray diffraction (XRD) techniques. A wide variety of other facilities for routine and novel techniques are also utilized including the Center for Nanophase Materials Science. Computational chemistry tools are employed to understand experimental results related to separation and other interfacial chemical processes and design better nanomaterials and ionic liquids. Commonly used methods include first principles density functional theory (DFT) and mixed quantum mechanical/molecular mechanical (QM/MM) techniques.

37

Dynamics of Propane in Silica Mesopores Formed upon Propylene Hydrogenation over Pt Nanoparticles by Time-Resolved FT-IR Spectroscopy  

E-Print Network (OSTI)

state distribution of propane between gas and mesopore phaseWavenumber (cm ) B Gas Phase Propane 2968 cm k 1 = 3.1 ± 0.4slices showing the gas phase propane component at 216, 648,

Waslylenko, Walter; Frei, Heinz

2008-01-01T23:59:59.000Z

38

Multitasking mesoporous nanomaterials for biorefinery applications  

DOE Green Energy (OSTI)

The incorporation of a different organic functional group into MSN provides a selective adsorbent for separation and purification of ?-tocopherol from microalgae oil. The functional group with electron deficient aromatic rings demonstrated high sequestration capacity and selectivity of {alpha}-tocopherol.

Kandel, Kapil [Ames Laboratory

2013-05-02T23:59:59.000Z

39

Energy conservation opportunity by the use of aerogel nanomaterials in steam pipes  

Science Conference Proceedings (OSTI)

Silica aerogels are unique porous nanomaterials consisting of more than 90% air and less than 10% solid silica in the form of highly cross-linked network structure. Because of their unique properties, i.e., large surface area, very low bulk density and ... Keywords: aerogels, energy conservation, nanomaterials, process simulation, thermal insulator

Sourena Sattari; Roghayeh Lotfi; Vahideh Baharmast

2008-02-01T23:59:59.000Z

40

BNL | CFN: Electronic Nanomaterials  

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

goals of our CFN research program in Electronic Nanomaterials involve implementing nanostructures for photovoltaic, photochemical, and electrochemical energy conversion. Our...

Note: This page contains sample records for the topic "mesoporous silica nanomaterials" 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

Dendrimer Templated Synthesis of One Nanometer Rh and Pt Particles Supported on Mesoporous Silica: Catalytic Activity for Ethylene and Pyrrole Hydrogenation.  

DOE Green Energy (OSTI)

Monodisperse rhodium (Rh) and platinum (Pt) nanoparticles as small as {approx}1 nm were synthesized within a fourth generation polyaminoamide (PAMAM) dendrimer, a hyperbranched polymer, in aqueous solution and immobilized by depositing onto a high-surface-area SBA-15 mesoporous support. X-ray photoelectron spectroscopy indicated that the as-synthesized Rh and Pt nanoparticles were mostly oxidized. Catalytic activity of the SBA-15 supported Rh and Pt nanoparticles was studied with ethylene hydrogenation at 273 and 293 K in 10 torr of ethylene and 100 torr of H{sub 2} after reduction (76 torr of H{sub 2} mixed with 690 torr of He) at different temperatures. Catalysts were active without removing the dendrimer capping but reached their highest activity after hydrogen reduction at a moderate temperature (423 K). When treated at a higher temperature (473, 573, and 673 K) in hydrogen, catalytic activity decreased. By using the same treatment that led to maximum ethylene hydrogenation activity, catalytic activity was also evaluated for pyrrole hydrogenation.

Huang, Wenyu; Kuhn, John N.; Tsung, Chia-Kuang; Zhang, Yawen; Habas, Susan E.; Yang, Peidong; Somorjai, Gabor A.

2008-05-09T23:59:59.000Z

42

Thin film nanoporous silica and graphene based biofuel cells (iBFCs) for low-power implantable medical device applications.  

E-Print Network (OSTI)

??This thesis describes the fabrication and characterization of an inorganic catalyst based glucose Biofuel cell using nanoporous (mesoporous) silica thin-film as a functional membrane. The… (more)

Sharma, Tushar

2011-01-01T23:59:59.000Z

43

Sustainable Energy Sources and Nanomaterials (+$5 million ...  

Science Conference Proceedings (OSTI)

Sustainable Energy Sources and Nanomaterials (+$5 million for Advanced Solar Technologies; +$4 million for Nanomaterial Environmental Health ...

2010-10-05T23:59:59.000Z

44

BNL | Center for Functional Nanomaterials (CFN) | Jobs  

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

Nanomaterials Postdoctoral Research Associate - Isolation of Device Quality Graphene (6482) - The Center for Functional Nanomaterials (CFN) at Brookhaven National...

45

Hierarchical Graphene Nanomaterials and Applications  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, 2011 TMS Annual Meeting & Exhibition. Symposium , 2011 Functional and Structural Nanomaterials: Fabrication, Properties, ...

46

Brookhaven Nanoscience and Nanomaterials  

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

Nanoscience and Nanomaterials Nanoscience and Nanomaterials The study of nanomaterials-materials on the scale of a nanometer, or a billionth of a meter-is a burgeoning area of study in physics, as well as materials science, chemistry, and biology. This research is an important because many physical and chemical properties of a material change dramatically at the nanoscale. At Brookhaven, physicists collaborate with materials scientists, biologists, and chemists on various nanomaterial research projects. One object under study is the carbon nanotube, a cylindrical carbon structure that is typically a few nanometers wide and can be up to millions of nanometers long. Carbon nanotubes possess exceptional electric and structural properties for their size, making them attractive for many applications. Now, Brookhaven scientists have found one more interesting property: A single nanotube can emit infrared light when a voltage is applied across it, which makes it the world's first electrically controllable light emitter. This research is ongoing, and the scientists hope to find a way to make the nanotube emit visible light.

47

BNL Center for Functional Nanomaterials  

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

Science and Cataylsis Xiao Tong is a staff scientist in the Interface Science and Catalysis group of the Center for Functional Nanomaterials at Brookhaven National Laboratory....

48

Energy Nanomaterials - Programmaster.org  

Science Conference Proceedings (OSTI)

Jul 31, 2011 ... In particular, the applications of nanomaterials in the following energy fields will be covered: - Solar Cells (Thin Films, Organic, Dye Sensitized, ...

49

MESOPOROUS METAL OXIDE MICROSPHERE ELECTRODE COMPOSITIONS AND ...  

Compositions and methods of making are provided for mesoporous metal oxide microspheres electrodes. The mesoporous metal oxide microsphere ...

50

Nanomaterials and the Environment & Instrumentation, Metrology...  

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

Exposure Assessment of Nanomaterials October 6-7, 2009: Nanomaterials and the Environment & Instrumentation, Metrology, and Analytical Methods November 17-18, 2009:...

51

Thermal Transport in Nanomaterials for Energy Applications  

Science Conference Proceedings (OSTI)

Symposium, Energy Nanomaterials. Presentation Title, Thermal Transport in Nanomaterials for Energy Applications. Author(s), Xinwei Wang. On-Site Speaker  ...

52

Nanomaterial-Based Electrochemical Biosensors and Bioassays  

Science Conference Proceedings (OSTI)

This book chapter summarizes the recent advance in nanomaterials for electrochemical biosensors and bioassays. Biofunctionalization of nanomaterials for biosensors fabrication and their biomedical applications are discussed.

Liu, Guodong; Mao, Xun; Gurung, Anant; Baloda, Meenu; Lin, Yuehe; He, Yuqing

2010-08-31T23:59:59.000Z

53

Direct template synthesis of mesoporous carbon and its application to supercapacitor electrodes  

SciTech Connect

A direct templating method which is facile, inexpensive and suitable for the large scale production of mesoporous carbon is reported herein. A meso-structure surfactant/silicate template was made in a solution phase and resorcinol-formaldehyde as a carbon precursor was incorporated into the template solution. After aging, carbonization and hydrofluoric acid (HF) etching, mesoporous carbon was obtained. Using X-ray diffraction, scanning and transmission electron microscopy and nitrogen sorption, the synthesis mechanism of the mesoporous carbon was elucidated. According to the small angle X-ray scattering measurements, the surface became smoother after the removal of the silica, indicating that the silica was mostly located at the pore surface of the carbon. Also, the calculation of the pore volume demonstrated that the silica was transferred into the pores of the carbon without structural collapse during HF etching. When the prepared mesoporous carbon was applied to a supercapacitor electrode, the rectangular shape of the cyclic voltammogram was less collapsed, even at a high scan rate, which is indicative of its high rate capability. This was due to the low resistance of the electrolyte in the pores (3.8 {Omega} cm{sup 2}), which was smaller than that of conventional activated carbon electrodes and even comparable to that of ordered mesoporous carbon electrodes. This improved performance was probably due to the well developed mesoporosity and high pore connectivity of the prepared mesoporous carbon.

Yoon, Songhun, E-mail: yoonshun@krict.re.kr [Advanced Chemical Technology Division, Korea Research Institute of Chemical Technology (KRICT), Sinseongno 19, Yuseong, Daejeon 305-600 (Korea, Republic of); Oh, Seung M. [Research Center for Energy Conversion and Storage (RCECS), School of Chemical and Biological Engineering and Institute of Chemical Process, College of Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Lee, Chulwee [Advanced Chemical Technology Division, Korea Research Institute of Chemical Technology (KRICT), Sinseongno 19, Yuseong, Daejeon 305-600 (Korea, Republic of)

2009-08-05T23:59:59.000Z

54

Environmental and IH Considerations in Nanomaterial ... - TMS  

Science Conference Proceedings (OSTI)

Nov 12, 2007 ... ENVIRONMENT ? HEALTH ? SAFETY ? PRODUCT STEWARDSHIP ?. • Establish a formal EHS management guideline for nanomaterials ...

55

Organized thiol functional groups in mesoporous core shell colloids  

Science Conference Proceedings (OSTI)

The co-condensation in situ of tetraethoxysilane (TEOS) and mercaptopropyltrimethoxysilane (MPTMS) using cetyltrimethylammonium bromide (CTAB) as a template results in the synthesis of multilayered mesoporous structured SiO{sub 2} colloids with 'onion-like' chemical environments. Thiol groups were anchored to an inner selected SiO{sub 2} porous layer in a bilayered core shell particle producing different chemical regions inside the colloidal layered structure. X-Ray Photoelectron Spectroscopy (XPS) shows a preferential anchoring of the -SH groups in the double layer shell system, while porosimetry and simple chemical modifications confirm that pores are accessible. We can envision the synthesis of interesting colloidal objects with defined chemical environments with highly controlled properties. - Graphical abstract: Mesoporous core shell SiO{sub 2} colloids with organized thiol groups. Highlights: Black-Right-Pointing-Pointer Double shell mesoporous silica colloids templated with CTAB. Black-Right-Pointing-Pointer Sequential deposition of mesoporous SiO{sub 2} layers with different chemistries. Black-Right-Pointing-Pointer XPS shows the selective functionalization of mesoporous layers with thiol groups.

Marchena, Martin H. [Gerencia Quimica, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica (CNEA), Avda. Gral. Paz 1499, B1650KNA Buenos Aires (Argentina); Granada, Mara [Centro Atomico Bariloche-CNEA, 8400 San Carlos de Bariloche (Argentina); Instituto Balseiro-Centro Atomico Bariloche-CNEA, San Carlos de Bariloche 8400 (Argentina); Bordoni, Andrea V. [Gerencia Quimica, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica (CNEA), Avda. Gral. Paz 1499, B1650KNA Buenos Aires (Argentina); Joselevich, Maria [Asociacion Civil Expedicion Ciencia, Cabrera 4948, C1414BGP Buenos Aires (Argentina); Troiani, Horacio [Centro Atomico Bariloche-CNEA, 8400 San Carlos de Bariloche (Argentina); Instituto Balseiro-Centro Atomico Bariloche-CNEA, San Carlos de Bariloche 8400 (Argentina); Williams, Federico J. [DQIAQyF-INQUIMAE FCEN, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon II, C1428EHA Buenos Aires (Argentina); Wolosiuk, Alejandro, E-mail: wolosiuk@cnea.gov.ar [Gerencia Quimica, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica (CNEA), Avda. Gral. Paz 1499, B1650KNA Buenos Aires (Argentina)

2012-03-15T23:59:59.000Z

56

Mesoporous carbon materials  

SciTech Connect

The invention is directed to a method for fabricating a mesoporous carbon material, the method comprising subjecting a precursor composition to a curing step followed by a carbonization step, the precursor composition comprising: (i) a templating component comprised of a block copolymer, (ii) a phenolic compound or material, (iii) a crosslinkable aldehyde component, and (iv) at least 0.5 M concentration of a strong acid having a pKa of or less than -2, wherein said carbonization step comprises heating the precursor composition at a carbonizing temperature for sufficient time to convert the precursor composition to a mesoporous carbon material. The invention is also directed to a mesoporous carbon material having an improved thermal stability, preferably produced according to the above method.

Dai, Sheng; Wang, Xiqing

2013-08-20T23:59:59.000Z

57

Mesoporous Titanium Oxide Based Anodes for Batteries  

Presentation_namefor the U.S. Department of Energy Mesoporous TiO 2 Anodes for Lithium Ion Batteries Mesoporous TiO 2 ... Increased energy density ?Mesoporous TiO. 2 .

58

Mesoporous carbons and polymers  

DOE Patents (OSTI)

A mesoporous material prepared by polymerizing a resorcinol/formaldehyde system from an aqueous solution containing resorcinol, formaldehyde and a surfactant and optionally pyrolyzing the polymer to form a primarily carbonaceous solid. The material has an average pore size between 4 and 75 nm and is suitable for use in liquid-phase surface limited applications, including sorbent, catalytic, and electrical applications.

Bell, William (Boulder, CO); Dietz, Steven (Denver, CO)

2001-01-01T23:59:59.000Z

59

Accelerated Technique for Carbon Mesoporous Materials - Energy ...  

Patent 8,114,510: Mesoporous carbon materials The invention is directed to a method for fabricating a mesoporous carbon material, the method ...

60

Assembly of Energy Nanomaterials via Water Based ...  

Science Conference Proceedings (OSTI)

Page 1. Assembly of Energy Nanomaterials via Water Based Assembly Paula T. Hammond Department of Chemical Engineering ...

Note: This page contains sample records for the topic "mesoporous silica nanomaterials" 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

Technical Approaches to Commercial Nanomaterials  

Science Conference Proceedings (OSTI)

... Nano-silica on Concrete Compressive Strength at Early Age: Nitza Garcia1; Luis Zapata1; O. Marcelo Suarez1; Mauricio Cabrera1; 1University of Puerto Rico

62

Magnetic mesoporous materials for removal of environmental wastes  

Science Conference Proceedings (OSTI)

We have synthesized two different magnetic mesoporous materials that can be easily separated from aqueous solutions by applying a magnetic field. Synthesized magnetic mesoporous materials, Mag-SBA-15 (magnetic ordered mesoporous silica) and Mag-OMC (magnetic ordered mesoporous carbon), have a high loading capacity of contaminants due to high surface area of the supports and high magnetic activity due to the embedded iron oxide particles. Application of surface-modified Mag-SBA-15 was investigated for the collection of mercury from water. The mercury adsorption using Mag-SBA-15 was rapid during the initial contact time and reached a steady-state condition, with an uptake of approximately 97% after 7 hours. Application of Mag-OMC for collection of organics from water, using fluorescein as an easily trackable model analyte, was explored. The fluorescein was absorbed into Mag-OMC within minutes and the fluorescent intensity of solution was completely disappeared after an hour. In another application, Mag-SBA-15 was used as a host of tyrosinase, and employed as recyclable catalytic scaffolds for tyrosinase-catalyzed biodegradation of catechol. Tyrosinase aggregates in Mag-SBA-15, prepared in a two step process of tyrosinase adsorption and crosslinking, could be used repeatedly for catechol degradation with no serious loss of enzyme activity. Considering these results of cleaning up water from toxic inorganic, organic and biochemical contaminants, magnetic mesoporous materials have a great potential to be employed for the removal of environmental contaminants and potentially for the application in large-scale wastewater treatment plants.

Kim, Byoung Chan; Lee, Jinwoo; Um, Wooyong; Kim, Jaeyun; Joo, Jin; Lee, Jin Hyung; Kwak, Ja Hun; Kim, Jae Hyun; Lee, Changha; Lee, Hongshin; Addleman, Raymond S.; Hyeon, Taeghwan; Gu, Man Bock; Kim, Jungbae

2011-09-15T23:59:59.000Z

63

POROUS SUBSTRATES FILLED WITH NANOMATERIALS - Energy ...  

A composition comprising: at least one porous carbon monolith, such as a carbon aerogel, comprising internal pores, and at least one nanomaterial, such as carbon ...

64

Center for Nanophase Materials Sciences (CNMS) - Nanomaterials...  

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

NANOMATERIALS THEORY INSTITUTE (NTI): THEORY, MODELING & SIMULATION CAPABILITIES NTI Computational Cluster The NTI maintains a 12 teraflop Beowulf cluster in support of the...

65

Center for Nanophase Materials Sciences (CNMS) - Nanomaterials...  

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

NANOMATERIALS THEORY INSTITUTE (NTI): Computational Nanoscience End-station (CNE) In analogy to experimental end-stations at large experimental facilities, the Computational...

66

Nanomaterials Analysis using a Scanning Electron Microscope ...  

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

Nanomaterials Analysis using a Scanning Electron Microscope Technology available for licensing: Steradian X-ray detection system increases the detection capability of SEMs during...

67

Low Cost Nanomaterials for PV Devices  

Impact: Low-cost solution for solar energy (Expand to lighting, batteries, etc) Low-cost Nanomaterials for PV Devices . Title: Slide 1 Author: Donna ...

68

Automated Transmission Kikuchi Diffraction for Nanomaterials ...  

Science Conference Proceedings (OSTI)

Presentation Title, Automated Transmission Kikuchi Diffraction for Nanomaterials Characterization in the SEM. Author(s), Scott Sitzman. On-Site Speaker ...

69

Silica Sand  

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

the molds and cores in foundries that make steel castings, and for casting gray iron, brass, aluminum and magnesium metals. Since silica sand has a very high melting point, it is...

70

Assembly of ordered carbon shells on semiconducting nanomaterials  

DOE Patents (OSTI)

In some embodiments of the invention, encapsulated semiconducting nanomaterials are described. In certain embodiments the nanostructures described are semiconducting nanomaterials encapsulated with ordered carbon shells. In some aspects a method for producing encapsulated semiconducting nanomaterials is disclosed. In some embodiments applications of encapsulated semiconducting nanomaterials are described.

Sutter, Eli Anguelova; Sutter, Peter Werner

2012-10-02T23:59:59.000Z

71

BNL | Center for Functional Nanomaterials (CFN)  

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

CFN People CFN People Center for Functional Nanomaterials An Office of Science User Facility Home Facilities Proximal Probes Nanofabrication Materials Synthesis and Characterization Theory and Computation Advanced UV and X-ray Probes Advanced Optical Spectroscopy and Microscopy Electron Microscopy Research Interface Science and Catalysis Soft and Bio Nanomaterials Electronic Nanomaterials Electron Microscopy Theory and Computation Working at CFN Arrival & Departure Reports & Publications Data Management The Guide to Brookhaven Safety Procedures Operations Plan COSA Training Hours of Operation Laser System Qualification Transport of Hazarous Materials Publications News CFN News Research Highlights iCFN, the CFN Newsletter Videos Events People Staff List Science Advisory Committee Users' Executive Committee

72

Aligned mesoporous architectures and devices.  

Science Conference Proceedings (OSTI)

This is the final report for the Presidential Early Career Award for Science and Engineering - PECASE (LDRD projects 93369 and 118841) awarded to Professor Yunfeng Lu (Tulane University and University of California-Los Angeles). During the last decade, mesoporous materials with tunable periodic pores have been synthesized using surfactant liquid crystalline as templates, opening a new avenue for a wide spectrum of applications. However, the applications are somewhat limited by the unfavorabe pore orientation of these materials. Although substantial effort has been devoted to align the pore channels, fabrication of mesoporous materials with perpendicular pore channels remains challenging. This project focused on fabrication of mesoporous materials with perpendicularly aligned pore channels. We demonstrated structures for use in water purification, separation, sensors, templated synthesis, microelectronics, optics, controlled release, and highly selective catalysts.

Brinker, C. Jeffrey; Lu, Yunfeng (University of California Los Angeles, Los Angeles, CA)

2011-03-01T23:59:59.000Z

73

Nanofabrication | Center for Functional Nanomaterials  

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

Nanofabrication Facility Nanofabrication Facility nanofabrication The Nanofabrication Facility is housed in a class 100/1000 clean room (5,000 sq. ft) dedicated to state-of-the art patterning and processing of thin films, nanomaterials, and devices. The instrumentation in the facility has been optimized to provide maximum flexibility for its users, with capabilities to pattern a variety of materials over a wide range of size scales, from 10 nanometers to 10 millimeters. The clean room is utilized to fabricate devices for nanoelectronics, nanophotonics, biomedical engineering, photovoltaics, x-ray optics, nanomagnetics and beyond. Capabilities High-resolution patterning by electron beam lithography, nanoimprint lithography, and optical lithography Thin-film deposition by electron beam and thermal evaporation, DC

74

Tritium Removal from Tritiated Water Using Mesoporous Silica  

Science Conference Proceedings (OSTI)

Detritiation and Isotope Separation / Proceedings of the Ninth International Conference on Tritium Science and Technology (Part 2)

A. Taguchi; R. Akai; M. Saito; Y. Torikai; M. Matsuyama; M. Ogura; S. Uchida

75

Functionalized Mesoporous Silica: An Effective Adsorbent for the ...  

Science Conference Proceedings (OSTI)

Gold thiosulfate, however, is not well-adsorbed by activated charcoal, making industrial scale use of thiosulfate for gold leaching impractical at present. Because ...

76

Nanomaterials Safety Implementation Plan, Ames Laboratory | Department of  

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

Nanomaterials Safety Implementation Plan, Ames Laboratory Nanomaterials Safety Implementation Plan, Ames Laboratory Nanomaterials Safety Implementation Plan, Ames Laboratory Ames Laboratory has limited activities involving nanomaterials. Potential hazards associated with nanomaterials work are addressed through the Laboratory's Integrated Safety Management System (ISMS) and specifically the Readiness Review process. Readiness Review provides the identification and evaluation of potential hazards and establishes effective control mechanisms to ensure protection of the employee and the environment. To date, hazards associated with projects involving nanomaterials have been determined to be amenable to conventional controls such as ventilation and use of personal protective equipment. The Laboratory recognizes that nanotechnology is an emerging field and that

77

Quaternary ammonium borohydride adsorption in mesoporous silicate MCM-48  

DOE Green Energy (OSTI)

Inorganic borohydrides have a high gravimetric hydrogen density but release H2 only under energetically unfavorable conditions. Surface chemistry may help in lowering thermodynamic barriers, but inclusion of inorganic borohydrides in porous silica materials has proved hitherto difficult or impossible. We show that borohydrides with a large organic cation are readily adsorbed inside mesoporous silicates, particularly after surface treatment. Thermal analysis reveals that the decomposition thermodynamics of tetraalkylammonium borohydrides are substantially affected by inclusion in MCM-48. Inelastic neutron scattering (INS) data show that the compounds adsorb on the silica surface. Evidence of pore loading is supplemented by DSC/TGA, XRD, FTIR, and BET isotherm measurements. Mass spectrometry shows significant hydrogen release at lower temperature from adsorbed borohydrides in comparison with the bulk borohydrides. INS data measured for partially decomposed samples indicates that the decomposition of the cation and anion is likely simultaneous. Additionally, these data confirm the formation of Si-H bonds on the silica surface upon decomposition of adsorbed tetramethylammonium borohydride.

Wolverton, Michael J [Los Alamos National Laboratory; Daemen, Luke L [Los Alamos National Laboratory; Hartl, Monika A [Los Alamos National Laboratory

2010-01-01T23:59:59.000Z

78

Self Assembled Monolayers on Mesoporous Supports (SAMMS ...  

... monolayers on mesoporous supports-SAMMS-and form effective sorbents for a wide variety of species including mercury, heavy metals, radionuclides ...

79

First-Principles-Based Nanomaterials Design for Solar Energy ...  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, 2012 TMS Annual Meeting & Exhibition. Symposium , Energy Nanomaterials. Presentation Title, First-Principles-Based ...

80

Fatigue and Fracture of Thin Films and Nanomaterials  

Science Conference Proceedings (OSTI)

Developments in flexible electronic materials systems and nanomaterials for energy harvesting or storage applications - Magnetic and shape memory properties ...

Note: This page contains sample records for the topic "mesoporous silica nanomaterials" 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

Nano-plasma Interactions in Optical and Meta-nanomaterials  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, Materials Science & Technology 2013. Symposium, Optical Nanomaterials for Photonics/Biophotonics. Presentation Title, Plasma ...

82

Visibly photoluminescent silica aerogels  

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

Visibly photoluminescent silica aerogels Title Visibly photoluminescent silica aerogels Publication Type Journal Article Year of Publication 1997 Authors Ayers, Michael R., and...

83

PATCHY SILICA-COATED SILVER NANOWIRES AS SERS SUBSTRATES  

SciTech Connect

We report a class of core-shell nanomaterials that can be used as efficient surface-enhancement Raman scattering (SERS) substrates. The core consists of silver nanowires, prepared through a chemical reduction process, that are used to capture 4- mercaptobenzoic acid (4-MBA), a model analyte. The shell was prepared through a modified Stöber method and consists of patchy or full silica coats. The formation of silica coats was monitored via transmission electron microscopy, UV-visible spectroscopy and phase-analysis light scattering for measuring effective surface charge. Surprisingly, the patchy silica coated silver nanowires are better SERS substrate than silver nanowires; nanomolar concentration of 4-MBA can be detected. In addition, “nano-matryoshka” configurations were used to quantitate/explore the effect of the electromagnetic field at the tips of the nanowire (“hot spots”) in the Raman scattering experiment.

Murph, S.; Murphy, C.

2013-03-29T23:59:59.000Z

84

Sandia National Labs: PCNSC: Departments: Nanomaterials Sciences  

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

Carlos Gutierrez Carlos Gutierrez Carlos Gutierrez Acting Manager Resources Department Outlook Calendar (PCs only) Link for others: Outlook Public Folders/ All Public Folders/ VP-01000/ Centers/ 01100/ 01112/ 01112 Calendar" 01112 Sharepoint Diamond Coatings Socorro DFT Code Departments Nanomaterials Sciences The Nanomaterials Sciences Department develops innovative science to enable integrated self-powered sensors and actuators for national security needs and provides a basis for a secure national energy future. In order to accomplish this vision, the department performs fundamental research in the areas of sensors and actuators, energy storage and delivery, energy conversion and harvesting, device integration and energy transport, solid state lighting, and the role of defects in all of these broad category

85

Mesoporous titania nanocrystals by hydrothermal template growth  

Science Conference Proceedings (OSTI)

Mesoporous TiO2 nanocrystals have been synthetized by a classical sol-gel route integrated by an hydrothermal growth step using monomeric (dodecylpyridinium chloride, DPC) or dimeric gemini-like (GS3) surfactants as template directing agents. ...

Giuseppe Cappelletti; Silvia Ardizzone; Francesca Spadavecchia; Daniela Meroni; Iolanda Biraghi

2011-01-01T23:59:59.000Z

86

Nanomaterial Laboratory Safety, Boise State University | Department of  

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

Nanomaterial Laboratory Safety, Boise State University Nanomaterial Laboratory Safety, Boise State University Nanomaterial Laboratory Safety, Boise State University A nanomaterial, as defined by The ASTM Committee on Nanotechnology, is a particle withlengths in 2 or 3 dimensions between 1 to 100 nm that mayor may not have a size related intensive property. Nanomaterials are of increasing interest due to their unique properties compared to the same material on the micro and macroscopic scales and their potential associated applications based upon these properties. The Boise State University Chemical Hygiene Plan (CHP) provides general guidance in regard to safely handling chemicals in a laboratory setting, but nanomaterials can come with unique and/or unknown risks and warrant being specifically addressed. Labs must adhere to the CHP and may need to

87

Nanomaterial Laboratory Safety, Boise State University | Department of  

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

Nanomaterial Laboratory Safety, Boise State University Nanomaterial Laboratory Safety, Boise State University Nanomaterial Laboratory Safety, Boise State University A nanomaterial, as defined by The ASTM Committee on Nanotechnology, is a particle withlengths in 2 or 3 dimensions between 1 to 100 nm that mayor may not have a size related intensive property. Nanomaterials are of increasing interest due to their unique properties compared to the same material on the micro and macroscopic scales and their potential associated applications based upon these properties. The Boise State University Chemical Hygiene Plan (CHP) provides general guidance in regard to safely handling chemicals in a laboratory setting, but nanomaterials can come with unique and/or unknown risks and warrant being specifically addressed. Labs must adhere to the CHP and may need to

88

Air-stable Nanomaterials for Efficient OLEDs and Solar Cells  

Air-stable Nanomaterials for Efficient OLEDs and Solar Cells . IB-2044, IB-2231 . ... U.S. DEPARTMENT OF ENERGY • OFFICE OF SCIENCE • UNIVERSITY OF CALIFORNIA.

89

Creation of Spinel and Functionally Graded Nano-Materials through ...  

Creation of Spinel and Functionally Graded Nano-Materials through Displacement Reactions Note: The technology described above is an early stage opportunity.

90

Particle Size Effect in Nanomaterials Using Phase Field Simulations  

Science Conference Proceedings (OSTI)

This reduction can also be predicted by Herring's scaling law. However, it is observed that the sintering of nanomaterials deviates from Herring scaling law.

91

A New Class of Molecularly-tailored Nanomaterials and Interfaces ...  

Science Conference Proceedings (OSTI)

Presentation Title, A New Class of Molecularly-tailored Nanomaterials and Interfaces For Energy Conversion and Thermal Management. Author(s), Ganpati  ...

92

Experiment Hazard Class 14.2 - Nanomaterials - Liquid Suspension  

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

are recommended for normal handling of suspended nanomaterials. Gloves must be plastic or rubber, selected to also protect against any solvent used. Dosimetry and...

93

Experiment Hazard Class 14.1 - Nanomaterials - Contained or in...  

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

- Gloves are recommended for normal handling of embedded nanomaterials. Gloves must be plastic or rubber, selected to also protect against any solvent used. Dosimetry and...

94

Large Scale Quantum-mechanical Calculations of Proteins, Nanomaterials...  

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

Large Scale Quantum-mechanical Calculations of Proteins, Nanomaterials and Other Large Systems Event Sponsor: Leadership Computing Facility Seminar Start Date: Dec 5 2013 - 2:00pm...

95

Design of an artificial functional nanomaterial with high recognition ability  

Science Conference Proceedings (OSTI)

An artificial macromolecule was designed as a novel nanomaterial with the backbone of phosphodiester and the side chain of functional molecules and nucleobases. The functional molecules tethered on d-threoninol and the nucleosides on d-ribose can be ... Keywords: Hybridization, Nanomaterial, Nucleobase, Photoregulation, Recognition ability

Xingguo Liang; Toshio Mochizuki; Taiga Fujii; Hiromu Kashida; Hiroyuki Asanuma

2012-06-01T23:59:59.000Z

96

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

97

Silica Scaling Removal Process  

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

systems Water treatment systems Water evaporation systems Potential mining applications (produced water) Industry applications for which silica scaling must be prevented Benefits:...

98

Silica Scaling Removal Process  

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

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...

99

Stepwise adsorption in a mesoporous metal?organic framework: experimental and computational analysis  

SciTech Connect

Stepwise adsorption in a metal-organic framework with both micro- and meso-pores is caused by adsorbates first filling the micropores, then adsorbing along the mesopore walls, and finally filling the mesopores.

Yuan, Daqiang; Getman, Rachel B.; Wei, Zhangwen; Snurr, Randall Q.; Zhou, Hong-Cai (TAM)

2012-04-02T23:59:59.000Z

100

NSLS Endstations | Center for Functional Nanomaterials  

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

UV and X-ray Probes UV and X-ray Probes The CFN operates three end-stations at the National Synchrotron Light Source (NSLS) for nanomaterials characterization. The station located at the X9 beamline performs simultaneous small- and wide-angle X-ray scattering experiments for nano-scale structural characterization of a variety of materials. The Ambient Pressure X-ray Photoelectron Spectroscopy (AP-XPS) station located at beamline X1A1 is capable of soft X-ray photoelectron spectroscopy for quantitative surface chemical analysis of a range of materials at gas pressures up to about 1 Torr. The undulator beamline U5UA hosts a station operating in ultra-high vacuum with a low-energy electron microscope (LEEM) and X-ray photo-emission electron microscope (XPEEM). The LEEM-XPEEM system can be used to study static and

Note: This page contains sample records for the topic "mesoporous silica nanomaterials" 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

BNL | Center for Functional Nanomaterials Data Management  

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

Data Management at CFN Data Management at CFN The Center for Functional Nanomaterials encourages Users to bring with them high capacity data storage drives (such as flash drives or portable hard-disk drives), which will allow them to manage their data on their own computers. The transfer of data is conducted consistently on secondary, data-retrieval computers. The CFN currently offers several resources for Users to manage their data: The CFN provides all onsite Users the opportunity to acquire an account on a CFN-dedicated computer server. This data server, which is managed by BNL's Information Technology Division (ITD), provides Users with a location to store data that was obtained at CFN, to which the Users may have access after departing CFN at the conclusion of an onsite visit.

102

Nanomaterials: Research, Development and Technology (R&D&T)  

Science Conference Proceedings (OSTI)

Abstract Scope, An overview will be given of nanomaterials Science and ... Roadmaps 2010 – 2020 for nanoscience environment and climate change and ... on the Particle Size of NiFe2O4 Spinel Nanopowder during Solid-State Reactions.

103

Atomistic simulations of chemomechanical processes in nanomaterials under extreme environments  

E-Print Network (OSTI)

The complex chemomechanical behavior of nanomaterials under extreme thermal and mechanical environments is of interest for a range of basic science and defense applications. By the limitation of experimental approaches for ...

Cho, Hansohl

2009-01-01T23:59:59.000Z

104

In situ XAS Characterization of Catalytic Nano-Materials with...  

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

XAS Characterization of Catalytic Nano-Materials with Applications to Fuel Cells and Batteries Friday, July 12, 2013 - 11:00am SLAC, Conference Room 137-322 Presented by Qingying...

105

ME EET Seminar: Conductive Polymer Matrix to Enable Si Nanomaterials...  

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

Conductive Polymer Matrix to Enable Si Nanomaterials for Energy Storage Speaker(s): Gao Liu Date: February 17, 2010 - 12:00pm Location: Campus TBD For more information about this...

106

Design and control of hierarchically structured nanomaterials  

E-Print Network (OSTI)

Hierarchically ordered porous oxides have garnered much interest because of the numerous applications that can be developed from these materials. The catalytic properties, separation ability, and ion exchangeability of these materials, specifically zeolites, make them great candidates for applications. One area which has not been heavily studied is ways to control the morphology and particle size of these materials through soft chemistry approaches. This dissertation looks at two methodologies which can be used to alter zeolitic particle morphology. The first is a dual templating approach which attempts to incorporate microporous walls within a mesoporous structure. The zeolitic material, silicalite-1, is used as a siliceous precursor for the formation of the mesoporous SBA-15 material. A battery of characterization techniques were used to identify the structural properties of the material, including porosimetry, diffraction, microscopy, and spectroscopy. The overall conclusion was that a material with different properties than the parent SBA-15 were obtained, but that no characterization technique could be used to show the definitive presence of the zeolite in the walls. Another technique studied is the growth of zeolitic materials within the water domains of microemulsions. The concept of a reverse microemulsion, a confined water droplet in a continuous oil phase makes it an interesting system for morphological control. The zeolitic materials should only be able to grow within the water domain, and the reactive materials should be less available as they are trapped in separate micelles. Zeolite A (LTA) and zeolite L (LTL), two technologically important zeolites, were studied. Enhanced growth, larger particles, and unique material aggregates are just a few of the observations made for the two systems. The development of these materials should facilitate the application of zeolite in emerging technologies. In particular, preliminary work has been done on the development of large zeolite crystals with tuned orientations and particle sizes. This research shows multiple ways in which particle size and morphology can be tuned simply by altering the chemistry and reaction conditions of the system. This research has led to unique findings dealing with large zeolite crystals, and should open the door for continued research in this area.

Carr, Charles Shane

2005-08-01T23:59:59.000Z

107

Lithium/Sulfur Batteries Based on Doped Mesoporous Carbon ...  

A sulfur/carbon composite material was prepared by heat treatment of doped mesoporous carbon and elemental sulfur at a temperature inside a stainless steel vessel ...

108

Hydrogen separation using silica membranes  

Science Conference Proceedings (OSTI)

Silica membranes were synthesized on tubular supports of alumina by dipping in silica colloidal solutions. The quality and the performance of the silica membranes were tested by experiments on single gas permeation and gas separation of mixed N2, ... Keywords: Knudsen diffusion, colloidal solution, gas permeation, hydrogen separation, silica membranes

Salvador Alfaroa; Miguel A. Valenzuelaa; Pedro Bosch

2008-11-01T23:59:59.000Z

109

Silica Embedded Metal Hydrides  

DOE Green Energy (OSTI)

A method to produce silica embedded metal hydride was developed. The product is a composite in which metal hydride particles are embedded in a matrix of silica. The silica matrix is highly porous. Hydrogen gas can easily reach the embedded metal hydride particles. The pores are small so that the metal hydride particles cannot leave the matrix. The porous matrix also protects the metal hydride particles from larger and reactive molecules such as oxygen, since the larger gas molecules cannot pass through the small pores easily. Tests show that granules of this composite can absorb hydrogen readily and withstand many cycles without making fines.

Heung, L.K. [Westinghouse Savannah River Company, AIKEN, SC (United States); Wicks, G.G.

1998-08-01T23:59:59.000Z

110

Engineered Nanomaterials, Sexy New Technology and Potential Hazards  

DOE Green Energy (OSTI)

Engineered nanomaterials enhance exciting new applications that can greatly benefit society in areas of cancer treatments, solar energy, energy storage, and water purification. While nanotechnology shows incredible promise in these and other areas by exploiting nanomaterials unique properties, these same properties can potentially cause adverse health effects to workers who may be exposed during work. Dispersed nanoparticles in air can cause adverse health effects to animals not merely due to their chemical properties but due to their size, structure, shape, surface chemistry, solubility, carcinogenicity, reproductive toxicity, mutagenicity, dermal toxicity, and parent material toxicity. Nanoparticles have a greater likelihood of lung deposition and blood absorption than larger particles due to their size. Nanomaterials can also pose physical hazards due to their unusually high reactivity, which makes them useful as catalysts, but has the potential to cause fires and explosions. Characterization of the hazards (and potential for exposures) associated with nanomaterial development and incorporation in other products is an essential step in the development of nanotechnologies. Developing controls for these hazards are equally important. Engineered controls should be integrated into nanomaterial manufacturing process design according to 10CFR851, DOE Policy 456.1, and DOE Notice 456.1 as safety-related hardware or administrative controls for worker safety. Nanomaterial hazards in a nuclear facility must also meet control requirements per DOE standards 3009, 1189, and 1186. Integration of safe designs into manufacturing processes for new applications concurrent with the developing technology is essential for worker safety. This paper presents a discussion of nanotechnology, nanomaterial properties/hazards and controls.

Beaulieu, R A

2009-05-04T23:59:59.000Z

111

Phosphorylated Mesoporous Carbon as a Solid Acid Catalyst  

Science Conference Proceedings (OSTI)

Mesoporous carbon catalyst supports are attractive due to their wide chemical stability while potentially increasing masstransport through and providing a path for larger molecules to access catalytic sites. Herein we report the synthesis of a 10 phosphorylated mesoporous carbon solid-acid catalyst characterized by NH3-TPD and isopropanol dehydration.

Dai, Sheng [ORNL; Mayes, Richard T [ORNL; Fulvio, Pasquale F [ORNL; Ma, Zhen [ORNL

2011-01-01T23:59:59.000Z

112

Hydrogen Storage on Metal-Doped Ordered Mesoporous Carbons  

E-Print Network (OSTI)

Hydrogen Storage on Metal-Doped Ordered Mesoporous Carbons Shuguang Deng New Mexico State Meeting, May 18, 2010 #12;Outline · Research group · Hydrogen storage: background and status · Synthesis Adsorption in Ordered Mesoporous Carbon through Clathrate Formation" Int. J. Hydrogen Energy, 34, 8583

Nishiguchi, Michele

113

Recent development of the synthesis and engineering applications of one-dimensional boron nitride nanomaterials  

Science Conference Proceedings (OSTI)

One-dimensional (1D) nanomaterials with novel photoelectric, magnetic, mechanical, and electronic transport properties have long been the research focus throughout the world. Herein, the recent achievements in preparation of 1D boron nitride nanomaterials, ...

Changhui Sun; Hongxiao Yu; Liqiang Xu; Qiang Ma; Yitai Qian

2010-01-01T23:59:59.000Z

114

Relating nanomaterial properties and microbial toxicity  

Science Conference Proceedings (OSTI)

Nanomaterials are meeting diverse needs in consumer and industrial products. Metal and metal oxide nanoparticles are among the most commonly used materials and their potential for adversely affecting environmental systems raises concern. Complex microbial consortia underlie environmental processes, and the potential toxicity of nanoparticles to microbial systems, and the consequent impacts on trophic balances, is particularly worrisome. The diverse array of metal and metal oxides, the different sizes and shapes that can be prepared and the variety of possible surface coatings complicate toxicity assessments. Further complicating toxicity interpretations are the diversity of microbial systems and their metabolic capabilities. Here, we review various studies focused on nanoparticle-microbial interactions in an effort to correlate the physical-chemical properties of engineered metal and metal oxide nanoparticles to their biological response. Gaining a predictive understanding of nanoparticle toxicity, based on the physical-chemical properties of the material, will be key to the design and responsible use of nanotechnologies. General conclusions regarding the parent material of the nanoparticle and nanoparticle s size and shape on potential toxicity can be made. However, the surface coating of the material, which can be altered significantly by environmental conditions, can ameliorate or promote microbial toxicity. Understanding nanoparticle transformations and how the nanoparticle surface can be designed to control toxicity represents a key area for further study. Additionally, the vast array of microbial species and their intrinsic metabolic capabilities complicates extrapolations of nanoparticle toxicity. A molecular-based understanding of the various microbial responses to nanoparticle-induced stress is needed. Ultimately, to interpret the effect and eventual fate of engineered materials in the environment, an understanding of the relationship between nanoparticle properties and microbial response will be essential.

Suresh, Anil K [ORNL; Pelletier, Dale A [ORNL; Doktycz, Mitchel John [ORNL

2013-01-01T23:59:59.000Z

115

Large Scale Quantum-mechanical Calculations of Proteins, Nanomaterials and  

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

Large Scale Quantum-mechanical Calculations of Proteins, Nanomaterials and Large Scale Quantum-mechanical Calculations of Proteins, Nanomaterials and Other Large Systems Event Sponsor: Leadership Computing Facility Seminar Start Date: Dec 5 2013 - 2:00pm Building/Room: Building 240/Room 4301 Location: Argonne National Laboratory Speaker(s): Dmitri G. Fedorov Speaker(s) Title: National Institute of Advanced Industrial Science and Technology (AIST) Host: Yuri Alexeev Our approach to large scale calculations is based on fragmenting a molecular system into pieces, and performing quantum-mechanical calculations of these fragments and their pairs in the fragment molecular orbital method (FMO). After a brief summary of the methodology, some typical applications to protein-ligand complexes, chemical reactions in explicit solvent, and nanomaterials (silicon nanowires, zeolites.

116

Flame Synthesis of One-Dimensional Metal Oxide Nanomaterials  

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

Synthesis of One-Dimensional Metal Oxide Nanomaterials Synthesis of One-Dimensional Metal Oxide Nanomaterials Alexei V. Saveliev Dept. of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695, USA Robust, scalable, and energy efficient methods of nanomaterial synthesis are needed to meet the demands of current and potential applications. Flames have been successfully applied for the synthesis of metal oxide and ceramic nanopowders largely composed of spherical particles and their aggregates. In recent years, premixed and diffusion flames have been employed for the synthesis of 1-D carbon nanoforms such as carbon fibers and carbon nanotubes. The extension of flame methods to gas phase and solid support synthesis of 1-D inorganic nanoforms is of great interest and significance. This talk presents

117

Lab Breakthrough: Nanomaterials Discoveries Lead to Possible Cancer  

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

Lab Breakthrough: Nanomaterials Discoveries Lead to Possible Cancer Lab Breakthrough: Nanomaterials Discoveries Lead to Possible Cancer Treatment Lab Breakthrough: Nanomaterials Discoveries Lead to Possible Cancer Treatment June 4, 2012 - 3:05pm Addthis Argonne nanoscientist Elena Rozhkova is studying ways to enlist nanoparticles to treat brain cancer. This nano-bio technology may eventually provide an alternative form of therapy that targets only cancer cells and does not affect normal living tissue. View the entire Lab Breakthrough playlist. Michael Hess Michael Hess Former Digital Communications Specialist, Office of Public Affairs What is a nano-bio catalyst? A nanoparticle that triggers specific reactions in cells. The particle attaches to unwanted (tumor) cells, and when researchers shine light on them, they kill the cells through oxidation.

118

Kinetics of silica polymerization  

DOE Green Energy (OSTI)

The polymerization of silicic acid in geothermal brine-like aqueous solutions to produce amorphous silica in colloidal form has been studied experimentally and theoretically. A large amount of high quality experimental data has been generated over the temperature rang 23 to 100{sup 0}C. Wide ranges of dissolved silica concentration, pH, and sodium chloride concentration were covered. The catalytic effects of fluoride and the reaction inhibiting effects of aluminum and boron were studied also. Two basic processes have been separately studied: the formation of new colloidal particles by the homogeneous nucleation process and the deposition of dissolved silica on pre-existing colloidal particles. A rigorous theory of the formation of colloidal particles of amorphous silica by homogeneous nucleation was developed. This theory employs the Lothe-Pound formalism, and is embodied in the computer code SILNUC which quantitatively models the homogeneous nucleation and growth of colloidal silica particles in more than enough detail for practical application. The theory and code were extensively used in planning the experimental work and analyzing the data produced. The code is now complete and running in its final form. It is capable of reproducing most of the experimental results to within experimental error. It is also capable of extrapolation to experimentally inaccessible conditions, i.e., high temperatures, rapidly varying temperature and pH, etc.

Weres, O.; Yee, A.; Tsao, L.

1980-05-01T23:59:59.000Z

119

Crystalline mesoporous zirconia catalysts having stable tetragonal pore wall structure  

DOE Patents (OSTI)

Methods for the preparation of new sulfated mesoporous zirconia materials/catalysts with crystalline pore walls of predominantly tetragonal crystal structure, characterized by nitrogen physisorption measurement, X-ray diffraction, transmission electron microscopy and catalytic tests using n-butane isomerization to iso-butane and alkylation of 1-naphthol with 4-tert-butylstyrene as probe reactions. Sulfate deposition is preferred for the transformation of a mesoporous precursor with amorphous pore walls into a material with crystalline pore walls maintaining the mesoporous characteristics.

Sachtler, Wolfgang M. H. (Evanston, IL); Huang, Yin-Yan (Evanston, IL)

1998-01-01T23:59:59.000Z

120

Crystalline mesoporous zirconia catalysts having stable tetragonal pore wall structure  

DOE Patents (OSTI)

Methods are disclosed for the preparation of new sulfated mesoporous zirconia materials/catalysts with crystalline pore walls of predominantly tetragonal crystal structure, characterized by nitrogen physical sorption measurement, X-ray diffraction, transmission electron microscopy and catalytic tests using n-butane isomerization to iso-butane and alkylation of 1-naphthol with 4-tert-butylstyrene as probe reactions. Sulfate deposition is preferred for the transformation of a mesoporous precursor with amorphous pore walls into a material with crystalline pore walls maintaining the mesoporous characteristics. 17 figs.

Sachtler, W.M.H.; Huang, Y.Y.

1998-07-28T23:59:59.000Z

Note: This page contains sample records for the topic "mesoporous silica nanomaterials" 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

Understanding nano-materials from first principles Leeor Kronik  

E-Print Network (OSTI)

Understanding nano-materials from first principles Leeor Kronik Department of Materials and Interfaces, Weizmann Institute of science, Rehovoth 76100 Nano-sized materials often exhibit exciting new traditional solid-state physics models are applicable to the intermediate nano- size range. As a result, first

Adler, Joan

122

iCFN | Center for Functional Nanomaterials Newsletter | Issue Archives  

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

iCFNCenter for Functional Nanomaterials Newsletter iCFNCenter for Functional Nanomaterials Newsletter iCFN Home iCFN Archives CFN Home Brookhaven National Laboratory Issue Archives Monday, December 23, 2013 iCFN: Message from CFN Director Emilio Mendez A Message from Stanislaus Wong Updates for the User Community News and Notes iCFN User Spotlight-Latha Venkataraman: Advancing the World's Smallest Devices 10 Questions with Kevin Yager Tuesday, April 16, 2013 iCFN: Message from CFN Director Emilio Mendez A Message from Nathalie Bouet Updates for the User Community News and Notes From Laboratory to Industry: Unlocking the Potential of Graphene Engineering Catalytic Contacts with Binary Nanocrystal Superlattices 10 Questions with Eli Sutter Wednesday, January 2, 2013 Welcome to iCFN A Message from Nathalie Bouet Updates for the User Community

123

2007 Synthesis and Self-assembly of Nanomaterials Workshop Summary  

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

Synthesis and Self-assembly of Nanomaterials Synthesis and Self-assembly of Nanomaterials Co-Organizers: Xiao-Min Lin (CNM) and Moonsub Shim (UIUC) A combination of advanced synthesis and assembly of molecular and nanoscale building blocks is one of the most promising routes to new macroscopic hybrid materials with unique and complex functionalities. During the past decade, many molecular and nanoscale building blocks have been synthesized with different morphologies and compositions, including conjugated polymers, inorganic nanocrystals, nanowires and nanotubes. Despite the continued advances in various aspects, many challenges remain to be addressed at different stages en route to applications. This full day workshop, organized by Xiao-Min Lin (CNM) and Moonsub Shim (UIUC), focused on how to

124

CFN Operations and Safety Awareness (COSA) Checklist Electronic Nanomaterials Facility  

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

Electronic Nanomaterials Facility Electronic Nanomaterials Facility Building 735 This COSA form must be completed for all experimenters working in the CFN and must be submitted to the CFN User Office for badge access. CFN Safety Awareness Policy: Each user must be instructed in the safe procedures in CFN related activities. CFN Facility Laboratory personnel shall keep readily available all relevant instructions and safety literature. Employee/Guest Name Life/Guest Number Department/Division ES&H Coordinator/Ext. Facility Manager COSA Trainer Guest User Staff USER ADMINISTRATION Checked in at User Administration and has valid BNL ID badge Safety Approval Form (SAF) approved. Training requirements completed (Indicate additional training specified in SAF or ESR in lines provided below):

125

Nanostructured Cobalt Oxide Clusters in Mesoporous Silica as Efficient Oxygen-Evolving Catalysts  

E-Print Network (OSTI)

as Efficient Oxygen- Evolving Catalysts Feng Jiao and Heinzof efficient and robust catalysts for the chemicaltransformations. Catalysts need to exhibit turnover

Jiao, Feng

2010-01-01T23:59:59.000Z

126

Mesoporous silica as a membrane for ultra-thin implantable direct glucose Tushar Sharma,a  

E-Print Network (OSTI)

failure warning systems, glucose and electrolyte sensors with systems such as an automated implantable car-linked hydro- gels, sulfonated polypropylene and cuprophan,20­22 have been used to facilitate glucose diffusion and separate the electrodes. Rao et al.20,23 and Atanasov and Wilkins24 have used hydro- phobic membranes

127

Mesoporous silica nanoparticles as smart and safe devices for regulating blood biomolecule levels  

SciTech Connect

Stimuli-responsive end-capped MSN materials are promising drug carriers that securely deliver a large payload of drug molecules without degradation or premature release. A general review of the recent progress in this field is presented, including a summary of a series of hard and soft caps for drug encapsulation and a variety of internal and external stimuli for controlled release of different therapeutics, a discussion of the biocompatibility of MSN both in vitro and in vivo, and a description of the sophisticated stimuli-responsive systems with novel capping agents and controlled release mechanism. The unique internal and external surfaces of MSN were utilized for the development of a glucose-responsive double delivery system end-capped with insulin. This unique system consists of functionalized MSNs capable of releasing insulin when the concentration of sugar in blood exceeds healthy levels. The insulin-free nanoparticles are then up taken by pancreatic cells, and release inside of them another biomolecule that stimulates the production of more insulin. The in vivo application of this system for the treatment of diabetes requires further understanding on the biological behaviors of these nanoparticles in blood vessels. The research presented in this dissertation demonstrated the size and surface effects on the interaction of MSNs with red blood cell membranes, and discovered how the surface of the nanoparticles can be modified to improve their compatibility with red blood cells and avoid their dangerous side effects. In order to optimize the properties of MSN for applying them as efficient intracellular drug carriers it is necessary to understand the factors that can regulate their internalization into and exocytosis out of the cells. The correlation between the particle morphology and aggregation of MSNs to the effectiveness of cellular uptake is discussed and compared with different cell lines. The differences in the degree of exocytosis of MSNs between healthy and cancer cells is reported and found to be responsible for the asymmetric transfer of the particles between both cell types. The fundamental studies on the hemocompatibility, endo- and exocytosis of MSN along with its ability to sequentially release multiple therapeutics in response to different stimuli, allow us to propose MSN as an intravascular vehicle with a great potential for various biomedical applications.

Zhao, Yan

2011-05-15T23:59:59.000Z

128

Reflectance of Surfactant-Templated Mesoporous Silica Thin Films: Simulations Versus Experiments  

E-Print Network (OSTI)

Annalen der Physik und Chemie, Leipzig (1895) 661–679. o [Annalen der Physik und Chemie 247 (9) [25] H. Lorentz, UeberAnnalen der Physik und Chemie 245 (4) (1880) 641–665. o [26

Hutchinson, Neal J.; Coquil, Thomas; Richman, Eric K.; Tolbert, Sarah H; Pilon, Laurent

2010-01-01T23:59:59.000Z

129

Program on Technology Innovation: Applications of Advanced Nanomaterials for Ultracapacitors  

Science Conference Proceedings (OSTI)

In the past decade, nanotechnology has become an important component in ultracapacitor research. Researchers have been able to identify the unique properties of nanomaterials, particularly carbon nanotubes, which can serve useful purposes in ultracapacitors. With nanometer-long diameters, nanotubes exhibit high surface area and low resistivity, among other unique properties, making them ideal candidates for ultracapacitor electrodes. Nanotube-based ultracapacitors have been built and tested in research l...

2007-03-29T23:59:59.000Z

130

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

131

The design, synthesis, and optimization of nanomaterials fabricated in supercritical carbon dioxide .  

E-Print Network (OSTI)

??This thesis presents investigations into the design and synthesis of nanomaterials in supercritical carbon dioxide (sc-CO?) as well as novel experimental design methodologies. First, the… (more)

Casciato, Michael John

2013-01-01T23:59:59.000Z

132

Electrochemical oxidation of ethanol on mesoporous NiO fibers in ...  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, 2014 TMS Annual Meeting & Exhibition. Symposium , 2014 Functional Nanomaterials: Synthesis, Properties and Applications.

133

SYNTHESIS OF MESOPOROUS ALUNIINOPHOSPHAI'ES AS POTENTIAL  

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

NEW CLASS MESOPOROUS ALUMINOPHOSPHATES AS POTENTIAL NEW CLASS MESOPOROUS ALUMINOPHOSPHATES AS POTENTIAL CATALYSTS IN THE UPGRADING PETROLEUM FEEDSTOCKS FINAL TECHNICAL REPORT REPORT PERIOD: SEPTEMBER 1, 2000 - FEBRUARY 31, 2005 PRINCIPAL INVESTIGATORS: CONRAD INGRAM, Ph. D. (PI) MARK MITCHELL, Ph. D. (CO-PI) PH: (404) 880-6898 FAX: (404) 880-6890 Email: cingram@cau.edu SUBMITTED TO: U.S.DEPARTMENT OF ENERGY REPORT DATE: AUGUST 31, 2005 GRANT NUMBER: DE-FG26-00NT40833 INSTITUTION: CLARK ATLANTA UNIVERSITY 223 JAMES P BRAWLEY DRIVE ATLANTA, GA 30314 I ABSTRACT A comprehensive investigation was conducted towards the synthesis and catalyic evaluation of high surface areas, uniform pore size, mesoporous aluminophosphates (AlPO 4 ) as potential catalysts for the upgrading of heavy petroleum feedstock, such as heavy crudes and petroleum residuum. The influence

134

Polymorphism of the glass former ethanol confined in mesoporous silicon  

E-Print Network (OSTI)

X-ray diffraction patterns of ethanol confined in parallel-aligned channels of approx. 10 nm diameter and 50 micrometer length in mesoporous silicon have been recorded as a function of filling fraction, temperature and for varying cooling and heating rates. A sorption isotherm, recorded in the liquid state, indicates a three monolayer thick, strongly adsorbed wall layer and a capillary condensed fraction of molecules in the pore center. Though the strongly adsorbed film remains in an amorphous state for the entire temperature range investigated, the capillary condensed molecules reproduce the polymorphism of bulk solid ethanol, that is the formation of either crystalline or glass-like states as a function of cooling rate. The critical rate necessary to achieve a vitrification in the mesopores is, however, at least two orders of magnitude smaller than in the bulk state. This finding can be traced both to pure geometrical constraints and quenched disorder effects, characteristic of confinement in mesoporous sil...

Henschel, Anke; Huber, Patrick; 10.1080/09500831003766999

2010-01-01T23:59:59.000Z

135

Polymorphism of the glass former ethanol confined in mesoporous silicon  

E-Print Network (OSTI)

X-ray diffraction patterns of ethanol confined in parallel-aligned channels of approx. 10 nm diameter and 50 micrometer length in mesoporous silicon have been recorded as a function of filling fraction, temperature and for varying cooling and heating rates. A sorption isotherm, recorded in the liquid state, indicates a three monolayer thick, strongly adsorbed wall layer and a capillary condensed fraction of molecules in the pore center. Though the strongly adsorbed film remains in an amorphous state for the entire temperature range investigated, the capillary condensed molecules reproduce the polymorphism of bulk solid ethanol, that is the formation of either crystalline or glass-like states as a function of cooling rate. The critical rate necessary to achieve a vitrification in the mesopores is, however, at least two orders of magnitude smaller than in the bulk state. This finding can be traced both to pure geometrical constraints and quenched disorder effects, characteristic of confinement in mesoporous silicon.

Anke Henschel; Klaus Knorr; Patrick Huber

2010-05-12T23:59:59.000Z

136

Structural simulations of nanomaterials self-assembled from ionic macrocycles.  

DOE Green Energy (OSTI)

Recent research at Sandia has discovered a new class of organic binary ionic solids with tunable optical, electronic, and photochemical properties. These nanomaterials, consisting of a novel class of organic binary ionic solids, are currently being developed at Sandia for applications in batteries, supercapacitors, and solar energy technologies. They are composed of self-assembled oligomeric arrays of very large anions and large cations, but their crucial internal arrangement is thus far unknown. This report describes (a) the development of a relevant model of nonconvex particles decorated with ions interacting through short-ranged Yukawa potentials, and (b) the results of initial Monte Carlo simulations of the self-assembly binary ionic solids.

van Swol, Frank B.; Medforth, Craig John (University of New Mexico, Albuquerque, NM)

2010-10-01T23:59:59.000Z

137

Nanomaterials for bio-functionalized electrodes: recent trends  

SciTech Connect

This review intends to highlight the interest of nanomaterials for building biologically-modified electrodes. Rather than giving a comprehensive overview of the topic, the present work intends to give a flavour on the most exciting achievements and most recent approaches to get (and use) nanostructured electrode surfaces (or electrodes modified with nano-objects) comprising biomolecules. It will mainly consider nano-engineered functional polymers, nano-sized objects such as nanoparticles, carbon nanotubes, graphene or related materials, as well as template-based nanostructures, as modifiers for bio-functionalised electrodes.

Walcarius, Alain; Minteer, Shelley D.; Wang, Joseph; Lin, Yuehe; Merkoci, Arben

2013-09-10T23:59:59.000Z

138

Publication activities of Russian organizations in the area of functional nanomaterials  

Science Conference Proceedings (OSTI)

A bibliometric study of publications on functional nanomaterials in Russia and worldwide is presented. The Scopus -- abstracts database with analytical facilities (Elsevier, Netherlands) is used for defining the publication activity of Russian organizations. ... Keywords: Russia, bibliographic databases, bibliometric analysis, citation, functional nanomaterials, geomonitoring, publication activity, the Scopus database, world information flow

N. S. Soloshenko; V. M. Efremenkova; O. V. Kirillova

2012-02-01T23:59:59.000Z

139

Combustion synthesis and nanomaterials Singanahally T. Aruna a,*, Alexander S. Mukasyan b,1  

E-Print Network (OSTI)

Combustion synthesis and nanomaterials Singanahally T. Aruna a,*, Alexander S. Mukasyan b,1 October 2008 Accepted 2 December 2008 Keywords: Combustion synthesis Self-propagating high-temperature synthesis Solution combustion Nanomaterials Catalysts Phosphors a b s t r a c t The recent developments

Mukasyan, Alexander

140

Using DNA to Build Nanomaterials | U.S. DOE Office of Science (SC)  

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

Using DNA to Build Nanomaterials Using DNA to Build Nanomaterials Stories of Discovery & Innovation Using DNA to Build Nanomaterials Enlarge Photo Photo courtesy of Brookhaven National Laboratory Oleg Gang, left, and Mircea Cotlet at Brookhaven's Center for Functional Nanomaterials. Enlarge Photo 05.09.11 Using DNA to Build Nanomaterials Scientists use complementary strands of synthetic DNA to build functional materials from the bottom up. Future applications include biosensors, optical nano-devices, and new kinds of solar cells. One central idea in the field of nanoscience is that if you can build things from the bottom up, atom-by-atom or molecule-by-molecule, you can rationally design materials to achieve desired functions. Taking a cue from how nature does this-using genetic code to instruct the

Note: This page contains sample records for the topic "mesoporous silica nanomaterials" 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

Burners and combustion apparatus for carbon nanomaterial production  

DOE Patents (OSTI)

The invention provides improved burners, combustion apparatus, and methods for carbon nanomaterial production. The burners of the invention provide sooting flames of fuel and oxidizing gases. The condensable products of combustion produced by the burners of this invention produce carbon nanomaterials including without limitation, soot, fullerenic soot, and fullerenes. The burners of the invention do not require premixing of the fuel and oxidizing gases and are suitable for use with low vapor pressure fuels such as those containing substantial amounts of polyaromatic hydrocarbons. The burners of the invention can operate with a hot (e.g., uncooled) burner surface and require little, if any, cooling or other forms of heat sinking. The burners of the invention comprise one or more refractory elements forming the outlet of the burner at which a flame can be established. The burners of the invention provide for improved flame stability, can be employed with a wider range of fuel/oxidizer (e.g., air) ratios and a wider range of gas velocities, and are generally more efficient than burners using water-cooled metal burner plates. The burners of the invention can also be operated to reduce the formation of undesirable soot deposits on the burner and on surfaces downstream of the burner.

Alford, J. Michael; Diener, Michael D; Nabity, James; Karpuk, Michael

2013-02-05T23:59:59.000Z

142

Burners and combustion apparatus for carbon nanomaterial production  

DOE Patents (OSTI)

The invention provides improved burners, combustion apparatus, and methods for carbon nanomaterial production. The burners of the invention provide sooting flames of fuel and oxidizing gases. The condensable products of combustion produced by the burners of this invention produce carbon nanomaterials including without limitation, soot, fullerenic soot, and fullerenes. The burners of the invention do not require premixing of the fuel and oxidizing gases and are suitable for use with low vapor pressure fuels such as those containing substantial amounts of polyaromatic hydrocarbons. The burners of the invention can operate with a hot (e.g., uncooled) burner surface and require little, if any, cooling or other forms of heat sinking. The burners of the invention comprise one or more refractory elements forming the outlet of the burner at which a flame can be established. The burners of the invention provide for improved flame stability, can be employed with a wider range of fuel/oxidizer (e.g., air) ratios and a wider range of gas velocities, and are generally more efficient than burners using water-cooled metal burner plates. The burners of the invention can also be operated to reduce the formation of undesirable soot deposits on the burner and on surfaces downstream of the burner.

Alford, J. Michael (Lakewood, CO); Diener, Michael D. (Denver, CO); Nabity, James (Arvada, CO); Karpuk, Michael (Boulder, CO)

2007-10-09T23:59:59.000Z

143

Silica aerogel: synthesis and applications  

Science Conference Proceedings (OSTI)

Silica aerogels have drawn a lot of interest both in science and technology because of their low bulk density (up to 95% of their volume is air), hydrophobicity, low thermal conductivity, high surface area, and optical transparency. Aerogels are synthesized ...

Jyoti L. Gurav; In-Keun Jung; Hyung-Ho Park; Eul Son Kang; Digambar Y. Nadargi

2010-01-01T23:59:59.000Z

144

Photovoltaic cells made from conjugated polymers infiltrated into mesoporous titania  

E-Print Network (OSTI)

Photovoltaic cells made from conjugated polymers infiltrated into mesoporous titania Kevin M photovoltaic cells by infiltrating the conjugated polymer regioregular poly 3-hexylthiophene into films for electrons to travel to an electrode after electron transfer has occurred. The photovoltaic cells have

McGehee, Michael

145

Mesoporous Carbon-based Materials for Alternative Energy Applications  

E-Print Network (OSTI)

Carbon-Silica Composite Aerogels." Nano Letters 2(3): 235.metal-carbonized aerogel composites as electrocatalysts forcarbons (Joo, 2001), carbon aerogels (Anderson, 2002; Ye,

Cross, Kimberly Michelle

2012-01-01T23:59:59.000Z

146

A Targeted Cancer Treatment using Nanomaterials | Advanced Photon Source  

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

When Roots Follow the Path of Least Resistance When Roots Follow the Path of Least Resistance Perfecting Catalytic Arrays A Stable Open Framework with Wide Open Spaces Pumping Through the Middle Crust Looking for Ways to Improve Vaccines Against the Deadly Rotavirus Science Highlights Archives: 2013 | 2012 | 2011 | 2010 2009 | 2008 | 2007 | 2006 2005 | 2004 | 2003 | 2002 2001 | 2000 | 1998 | Subscribe to APS Science Highlights rss feed A Targeted Cancer Treatment using Nanomaterials AUGUST 27, 2009 Bookmark and Share Optical fluorescent imaging of the TiO2-mAb binding to the single brain cancer cells. The bare titianium dioxide nanoparticle bonds with an antibody and attaches itself to brain cancer cells. When exposed to concentrated white light, the titanium dioxide creates free radicals of oxygen that cause the cancer cells to die. Image courtesy of Argonne

147

Multifunctional virus scaffolds fore energy applications : nanomaterials synthesis and two dimensional assembly  

E-Print Network (OSTI)

Biological systems inherently posses the ability to synthesize and assemble nanomaterials with remarkable precision, as evident in biomineralization. These unique abilities of nature continue to inspire us to develop new ...

Nam, Ki Tae

2007-01-01T23:59:59.000Z

148

Synthesis and characterization of 1D ceria nanomaterials for CO oxidation and steam reforming of methanol  

Science Conference Proceedings (OSTI)

Novel one-dimensional (1D) ceria nanostructure has been investigated as a promising and practical approach for the reforming of methanol reaction. Size and shape of the ceria nanomaterials are directly involved with the catalytic activities. Several ...

Sujan Chowdhury; Kuen-Song Lin

2011-01-01T23:59:59.000Z

149

Removal of dissolved and colloidal silica  

DOE Patents (OSTI)

Small amorphous silica particles are used to provide a relatively large surface area upon which silica will preferentially adsorb, thereby preventing or substantially reducing scaling caused by deposition of silica on evaporative cooling tower components, especially heat exchange surfaces. The silica spheres are contacted by the cooling tower water in a sidestream reactor, then separated using gravity separation, microfiltration, vacuum filtration, or other suitable separation technology. Cooling tower modifications for implementing the invention process have been designed.

Midkiff, William S. (Ruidoso, NM)

2002-01-01T23:59:59.000Z

150

Stabilized fuel with silica support structure  

DOE Patents (OSTI)

This report describes a stabilized fuel which is supported by a silica support structure. The silica support structure provides a low density, high porosity vehicle for safely carrying hydrocarbon fuels. The silica support structure for hydrocarbon fuel does not produce toxic material residues on combustion which would pose environmentally sensitive disposal problems. The silica stabilized fuel composition is useful as a low temperature, continuous burning fire starter for wood or charcoal.

Poco, J.F.; Hrubesh, L.W.

1991-12-31T23:59:59.000Z

151

Green chemical transformation of phenolic pollutants using mesoporous NiO nanocrystals with sheet-like morphology  

Science Conference Proceedings (OSTI)

We report the fabrication of hierarchical mesoporous NiO nanocrystals (NCs) with sheet-like morphology via a simple, and eco-friendly hydrothermal method. Mesoporous NiO particles were characterized by small- and wide-angle X-ray diffraction, nitrogen ... Keywords: chemical transformation, mesoporous NiO, nanocatalysts, pollutants

Mohamed Khairy; Sherif A. El-Safty; Mohamed Ismael; M. A. Shenashen

2012-02-01T23:59:59.000Z

152

In Situ Transmission Electron Microscopy Characterization of Nanomaterials  

E-Print Network (OSTI)

With the recent development of in situ transmission electron microscopy (TEM) characterization techniques, the real time study of property-structure correlations in nanomaterials becomes possible. This dissertation reports the direct observations of deformation behavior of Al2O3-ZrO2-MgAl2O4 (AZM) bulk ceramic nanocomposites, strengthening mechanism of twins in YBa2Cu3O7-x (YBCO) thin film, work hardening event in nanocrystalline nickel and deformation of 2wt% Al doped ZnO (AZO) thin film with nanorod structures using the in situ TEM nanoindentation tool. The combined in situ movies with quantitative loading-unloading curves reveal the deformation mechanism of the above nanomaterial systems. At room temperature, in situ dynamic deformation studies show that the AZM nanocomposites undergo the deformation mainly through the grain-boundary sliding and rotation of small grains, i.e., ZrO2 grains, and some of the large grains, i.e., MgAl2O4 grains. We observed both plastic and elastic deformations in different sample regions in these multi-phase ceramic nanocomposites at room temperature. Both ex situ (conventional) and in situ nanoindentation were conducted to reveal the deformation of YBCO films from the directions perpendicular and parallel to the twin interfaces. Hardness measured perpendicular to twin interfaces is ~50% and 40% higher than that measured parallel to twin interfaces, by ex situ and in situ, respectively. By using an in situ nanoindentation tool inside TEM, dynamic work hardening event in nanocrystalline nickel was directly observed. During stain hardening stage, abundant Lomer-Cottrell (L-C) locks formed both within nanograins and against twin boundaries. Two major mechanisms were identified during interactions between L-C locks and twin boundaries. Quantitative nanoindentation experiments recorded during in situ experiments show an increase of yield strength from 1.64 to 2.29 GPa during multiple loading-unloading cycles. In situ TEM nanoindentation has been conducted to explore the size dependent deformation behavior of two different types (type I: ~ 0.51 of width/length ratio and type II: ~ 088 ratio) of AZO nanorods. During the indentation on type I nanord structure, annihilation of defects has been observed which is caused by limitation of the defect activities by relatively small size of the width. On the other hand, type II nanorod shows dislocation activities which enhanced the grain rotation under the external force applied on more isotropic direction through type II nanorod.

Lee, Joon Hwan 1977-

2012-12-01T23:59:59.000Z

153

Cytotoxicological Response to Engineered Nanomaterials: A Pathway-Driven Process  

E-Print Network (OSTI)

Nanoparticles, while included in a growing number of consumer products, may pose risks to human health due to heavy metal leaching and/or the production of reactive oxygen species following exposures. Subcellular mechanisms of action triggered as a result of exposure to various nanoparticles are still largely unexplored. In this work, an effort to elucidate such toxicological parameters was accomplished by evaluating oxidative stress generation, changes in gene and protein expression, and cell cycle status after low-dose exposures to a variety of metal and carbon-based nanomaterials in primary human dermal cells. Additionally, mitigation of nanoparticle toxicity via microencapsulation was investigated to assess the feasibility of utilizing nanomaterials in dermally implantable biosensor applications. Cellular immune and inflammatory processes were measured via qPCR and immunoblotting, which revealed gene and protein expression modulation along the NF-kappaB pathway after a variety of nanoparticle exposures. The role of immunoregulatory transcription factor NF-kappaB was examined in an oxidative stress context in cells exposed to a panel of nanoparticles, whereby glutathione conversion and modulation of oxidative stress proteins in normal and NF-kappaB knockdown human dermal fibroblasts were monitored. Results revealed decreased antioxidant response and corresponding increased levels of oxidative stress and cell death in exposed normal cells, compared to NF-kappaB incompetent cells. However, reactive oxygen species production was not an absolute precursor to DNA damage, which was measured by the comet assay, gamma-H2AX expression, and flow cytometry. Protein analysis revealed that map kinase p38, rather than p53, was involved in the halting of the cell cycle in S-phase after ZnO exposures, which caused DNA double strand breaks. Microencapsulation of fluorescent quantum dot nanoparticles, specifically, was utilized as a method to improve system functionality and surrounding cellular viability for the purpose of a dermal analyte detection assay. In vitro results indicated a functional localization of nanoparticles, as well as cessation of cellular uptake. Subsequently, cellular metabolism was unaffected over the range of time and concentrations tested in comparison to unencapsulated quantum dot treatments, indicating the usefulness of this technique in developing nanoparticle-driven biomedical applications.

Romoser, Amelia Antonia

2012-05-01T23:59:59.000Z

154

Macro-ions collapse leading to hybrid bio-nanomaterials.  

DOE Green Energy (OSTI)

I used supramolecular self-assembling cyanine and the polyamine spermine binding to Escherichia coli genomic DNA as a model for DNA collapse during high throughput screening. Polyamine binding to DNA converts the normally right handed B-DNA into left handed Z-DNA conformation. Polyamine binding to DNA was inhibited by the supramolecular self-assembling cyanine. Self-assembly of cyanine upon DNA scaffold was likewise competitively inhibited by spermine as signaled by fluorescence quench from DNA-cyanine ensemble. Sequence of DNA exposure to cyanine or spermine was critical in determining the magnitude of fluorescence quench. Methanol potentiated spermine inhibition by >10-fold. The IC{sub 50} for spermine inhibition was 0.35 {+-} 0.03 {micro}M and the association constant Ka was 2.86 x 10{sup -6}M. Reversibility of the DNA-polyamine interactions was evident from quench mitigation at higher concentrations of cyanine. System flexibility was demonstrated by similar spermine interactions with {lambda}DNA. The choices and rationale regarding the polyamine, the cyanine dye as well as the remarkable effects of methanol are discussed in detail. Cyanine might be a safer alternative to the mutagenic toxin ethidium bromide for investigating DNA-drug interactions. The combined actions of polyamines and alcohols mediate DNA collapse producing hybrid bio-nanomaterials with novel signaling properties that might be useful in biosensor applications. Finally, this work will be submitted to Analytical Sciences (Japan) for publication. This journal published our earlier, related work on cyanine supramolecular self-assembly upon a variety of nucleic acid scaffolds.

Achyuthan, Komandoor E.

2009-10-01T23:59:59.000Z

155

Method for rapidly producing microporous and mesoporous materials  

DOE Patents (OSTI)

An improved, rapid process is provided for making microporous and mesoporous materials, including aerogels and pre-ceramics. A gel or gel precursor is confined in a sealed vessel to prevent structural expansion of the gel during the heating process. This confinement allows the gelation and drying processes to be greatly accelerated, and significantly reduces the time required to produce a dried aerogel compared to conventional methods. Drying may be performed either by subcritical drying with a pressurized fluid to expel the liquid from the gel pores or by supercritical drying. The rates of heating and decompression are significantly higher than for conventional methods.

Coronado, Paul R. (Livermore, CA); Poco, John F. (Livermore, CA); Hrubesh, Lawrence W. (Pleasanton, CA); Hopper, Robert W. (Danville, CA)

1997-01-01T23:59:59.000Z

156

Method for rapidly producing microporous and mesoporous materials  

DOE Patents (OSTI)

An improved, rapid process is provided for making microporous and mesoporous materials, including aerogels and pre-ceramics. A gel or gel precursor is confined in a sealed vessel to prevent structural expansion of the gel during the heating process. This confinement allows the gelation and drying processes to be greatly accelerated, and significantly reduces the time required to produce a dried aerogel compared to conventional methods. Drying may be performed either by subcritical drying with a pressurized fluid to expel the liquid from the gel pores or by supercritical drying. The rates of heating and decompression are significantly higher than for conventional methods. 3 figs.

Coronado, P.R.; Poco, J.F.; Hrubesh, L.W.; Hopper, R.W.

1997-11-11T23:59:59.000Z

157

Elevated Silica Project at Palisades -- Final Report  

Science Conference Proceedings (OSTI)

Silica concentrations as high as 2-5 ppm in the primary water during startup at some pressurized water reactor (PWR) plants exceed the prevailing industry diagnostic limit of 1 ppm and raise concerns about the possible formation of tenacious silicate deposits on the fuel. To minimize the costs of removing excess silica at fuel outages, EPRI initiated an investigation on the effect of silica on fuel performance. This report documents the final stage of this research, a fuel surveillance project at Palisad...

2000-10-27T23:59:59.000Z

158

PWR RCS Elevated Silica - Fuel Surveillance  

Science Conference Proceedings (OSTI)

Many PWR plants have recently experienced silica concentration as high as 2-5 ppm in the primary water at startup. That level exceeds the prevailing industry diagnostic limit of 1 ppm for safeguarding fuel from potential deposition of tenacious silicates. The high silica experience is primarily limited to plants using silica-containing Boroflex storage racks, which tend to decay in the intense radiation environment in the storage pool. Some plants using recycled boric acid have also experienced high star...

1999-07-28T23:59:59.000Z

159

The Assembly of Nano-materials Using Bio-Scaffolding C. Steven Yun, Jody L. Major, Geoffrey F. Strouse*  

E-Print Network (OSTI)

The Assembly of Nano-materials Using Bio-Scaffolding C. Steven Yun, Jody L. Major, Geoffrey F for electronics and sensing applications. Bio-engineered architectures arising from the fusion of nano of biological materials and the intrinsic optical and electronic properties of nano-materials. The criteria

Strouse, Geoffrey F.

160

Can Ionic Liquids Be Used As Templating Agents For Controlled Design of Uranium-Containing Nanomaterials?  

SciTech Connect

Nanostructured uranium oxides have been prepared in ionic liquids as templating agents. Using the ionic liquids as reaction media for inorganic nanomaterials takes advantage of the pre-organized structure of the ionic liquids which in turn controls the morphology of the inorganic nanomaterials. Variation of ionic liquid cation structure was investigated to determine the impact on the uranium oxide morphologies. For two ionic liquid cations, increasing the alkyl chain length increases the aspect ratio of the resulting nanostructured oxides. Understanding the resulting metal oxide morphologies could enhance fuel stability and design.

Visser, A.; Bridges, N.; Tosten, M.

2013-04-09T23:59:59.000Z

Note: This page contains sample records for the topic "mesoporous silica nanomaterials" 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

Synthesis and textural evolution of alumina particles with mesoporous structures  

Science Conference Proceedings (OSTI)

Alumina particles with mesostructures were synthesized through a chemical precipitation method by using different inorganic aluminum salts followed by a heterogeneous azeotropic distillation and calcination process. The obtained mesoporous {gamma}-alumina particles were systematically characterized by the X-ray diffraction, transmission electron microscopy and nitrogen adsorption-desorption measurement. Effects of the aluminum salt counter anion, pH value and the azeotropic distillation process on the structural or textural evolution of alumina particles were investigated. It is found that Cl{sup -} in the reaction solution can restrain the textural evolution of the resultant precipitates into two-dimensional crystallized pseudoboehmite lamellae during the heterogeneous azeotropic distillation, and then transformed into {gamma}-Al{sub 2}O{sub 3} particles with mesostructures after further calcination at 1173 K, whereas coexisting SO{sub 4}{sup 2-} can promote above morphology evolution and then transformed into {gamma}-Al{sub 2}O{sub 3} nanofibers after calcination at 1173 K. Moreover nearly all materials retain relatively high specific surface areas larger than 100 m{sup 2} g{sup -1} even after calcinations at 1173 K. - Graphical abstract: Co-existing Cl{sup -} is beneficial for the formation of {gamma}-alumina nanoparticles with mesostructures during the precipitation process. Interparticle and intraparticle mesopores can be derived from acidic solution and near neutral solution, respectively.

Liu Xun [College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072 (China); Peng Tianyou, E-mail: typeng@whu.edu.c [College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072 (China); Yao Jinchun; Lv Hongjin; Huang Cheng [College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072 (China)

2010-06-15T23:59:59.000Z

162

Text of The Solubility of Silica in Calcium Ferrite Slags  

Science Conference Proceedings (OSTI)

To successfully use lime flux, the dissolution of silica in calcium-ferrite slags must ... samples were chemically analyzed by standard methods for calcium, silica, ...

163

Synthesis and properties of chitosan-silica hybrid aerogels  

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

Synthesis and properties of chitosan-silica hybrid aerogels Title Synthesis and properties of chitosan-silica hybrid aerogels Publication Type Journal Article Year of Publication...

164

Synthesis and properties of Chitosan-silica hybrid aerogels  

E-Print Network (OSTI)

chitosan-silica composite aerogels can be easily synthesizedphysical properties of these aerogels. These materials may1. Top: Chitosan-silica aerogel (sample 4), Bottom: Same

Ayers, Michael R.; Hunt, Arlon J.

2001-01-01T23:59:59.000Z

165

Investigations of silica alcogel aging using coherent light  

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

Investigations of silica alcogel aging using coherent light Title Investigations of silica alcogel aging using coherent light Publication Type Journal Article Year of Publication...

166

Preparation and characterization of Ni(OH)2 and NiO mesoporous nanosheets  

Science Conference Proceedings (OSTI)

Mesoporous nanosheets of single-crystalline ?-nickel hydroxide (?-Ni(OH)2) were successfully synthesized via a facile hydrothermal method using Ni(NO3)2 ? 6H2O as precursor in a mixed solution ...

Changyu Li; Shouxin Liu

2012-01-01T23:59:59.000Z

167

Low-temperature dynamics of water confined in a hydrophobic mesoporous material  

E-Print Network (OSTI)

Quasielastic neutron scattering was used to study the dynamics of three-dimensional confined water in a hydrophobic mesoporous material designated as CMK-1 in the temperature range from 250 to 170 K. We observe a crossover ...

Chu, Xiang-qiang

168

Preparation of Catalytic Nanoparticles in Mesoporous Silica Film for Oriented Growth of Single-Walled Carbon Nanotubes  

E-Print Network (OSTI)

it is expected as an ideal field emitter that can realize lower threshold voltage and higher electric current, vertical orientation of SWNTs is accepted as a key technology toward practical usage as a field emitter [1

Maruyama, Shigeo

169

Pressure Drops Due to Silica Scaling  

DOE Green Energy (OSTI)

Experience with reinjection returns in many geothermal fields has prompted a move towards injecting waste fluids at some distance from the production field. This means that often, reinjection pipelines cover very long distances. If the waste water in the pipelines is supersaturated with respect to amorphous silica, then the deposition of silica in these pipelines is almost certain. Although the deposit may be of negligible thickness, the inner surface characteristics of the pipe will be different to those of clean mild steel. During a silica scaling experiment. geothermal brine was passed through a series of pipes of different sizes and over a period of three weeks, silica scale formed on the inner surface. The pressure drop along a distance of approximately 5m was measured by a water manometer in all test pipe sections. Significant pressure drop was observed during this time and can be correlated with the increase in the friction factor of the pipe walls due to silica scaling.

Brown, K.L.; Freeston, D.H.; Dimas, Z.O.; Slatter, A.

1995-01-01T23:59:59.000Z

170

Design of a functional nanomaterial with recognition ability for constructing light-driven nanodevices  

Science Conference Proceedings (OSTI)

An artificial macromolecule (foldamer) was designed as a novel nanomaterial with the backbone of phosphodiester and the side chain of functional molecules and nucleobases. The functional molecules tethered on D-threoninol and the nucleosides on D-ribose ... Keywords: hybridization, nanodevice, nucleobase, photoregulation

Xingguo Liang; Toshio Mochizuki; Taiga Fujii; Hiromu Kashida; Hiroyuki Asanuma

2010-06-01T23:59:59.000Z

171

Synthesis, properties, and applications of low-dimensional carbon-related nanomaterials  

Science Conference Proceedings (OSTI)

In recent years, many theoretical and experimental studies have been carried out to develop one of the most interesting aspects of the science and nanotechnology which is called carbon-related nanomaterials. The goal of this paper is to provide a review ...

Ali Mostofizadeh; Yanwei Li; Bo Song; Yudong Huang

2011-01-01T23:59:59.000Z

172

Effect of the graphite electrode material on the characteristics of molten salt electrolytically produced carbon nanomaterials  

SciTech Connect

The electrochemical erosion of a graphite cathode during the electrolysis of molten lithium chloride salt may be used for the preparation of nano-structured carbon materials. It has been found that the structures and morphologies of these carbon nanomaterials are dependent on those of the graphite cathodes employed. A combination of tubular and spherical carbon nanostructures has been produced from a graphite with a microstructure of predominantly planar micro-sized grains and a minor fraction of more irregular nano-sized grains, whilst only spherical carbon nanostructures have been produced from a graphite with a microstructure of primarily nano-sized grains. Based on the experimental results, a best-fit regression equation is proposed that relates the crystalline domain size of the graphite reactants and the carbon products. The carbon nanomaterials prepared possess a fairly uniform mesoporosity with a sharp peak in pore size distribution at around 4 nm. The results are of crucial importance to the production of carbon nanomaterials by way of the molten salt electrolytic method. - Highlights: {yields} Carbon nanomaterials are synthesised by LiCl electrolysis with graphite electrodes. {yields} The degree of crystallinity of graphite reactant and carbon product are related. {yields} A graphite reactant is identified that enables the preparation of carbon nanotubes. {yields} The carbon products possess uniform mesoporosity with narrow pore size distribution.

Kamali, Ali Reza, E-mail: ark42@cam.ac.uk; Schwandt, Carsten; Fray, Derek J.

2011-10-15T23:59:59.000Z

173

Carbon Nanomaterials: The Ideal Interconnect Technology for Next-Generation ICs  

Science Conference Proceedings (OSTI)

Editor's note:Carbon nanotubes and graphene nanoribbons are two promising next-generation interconnect technologies. Electrical modeling and performance analysis have demonstrated the superiority of these emerging technologies compared to conventional ... Keywords: design and test, carbon nanomaterials, carbon nanotube (CNT), graphene nanoribbon (GNR), electrical interconnects, optical interconnects, RF or wireless interconnects, on-chip vias, through-silicon vias (TSVs), delay, power

Hong Li; Chuan Xu; Kaustav Banerjee

2010-07-01T23:59:59.000Z

174

Graphene based nanomaterials for VLSI interconnect and energy-storage applications  

Science Conference Proceedings (OSTI)

As IC feature sizes continue to be scaled below 45 nanometer, copper wires exhibit significant "size effects" resulting in a sharp rise in their resistivity, which, in turn, has adverse impact both on their performance as well as reliability--in the ... Keywords: carbon nanomaterials, carbon nanotubes, graphene nano-ribbons, interconnects, passives.

Kaustav Banerjee

2009-07-01T23:59:59.000Z

175

JOM January 201148 www.tms.org/jom.html OverviewOverviewNanomaterials for Renewable Energy  

E-Print Network (OSTI)

JOM · January 201148 www.tms.org/jom.html OverviewOverviewNanomaterials for Renewable Energy Global to fundamental advances in direct renewable energy and ener- gy storage and conversion which are needed to enable renewable energy and meet the general energy challenges and associated environmental effects. This paper

176

Anisotropic Hexagonal Boron Nitride Nanomaterials - Synthesis and Applications  

SciTech Connect

Boron nitride (BN) is a synthetic binary compound located between III and V group elements in the Periodic Table. However, its properties, in terms of polymorphism and mechanical characteristics, are rather close to those of carbon compared with other III-V compounds, such as gallium nitride. BN crystallizes into a layered or a tetrahedrally linked structure, like those of graphite and diamond, respectively, depending on the conditions of its preparation, especially the pressure applied. Such correspondence between BN and carbon readily can be understood from their isoelectronic structures [1, 2]. On the other hand, in contrast to graphite, layered BN is transparent and is an insulator. This material has attracted great interest because, similar to carbon, it exists in various polymorphic forms exhibiting very different properties; however, these forms do not correspond strictly to those of carbon. Crystallographically, BN is classified into four polymorphic forms: Hexagonal BN (h-BN) (Figure 1(b)); rhombohedral BN (r-BN); cubic BN (c-BN); and wurtzite BN (w-BN). BN does not occur in nature. In 1842, Balmain [3] obtained BN as a reaction product between molten boric oxide and potassium cyanide under atmospheric pressure. Thereafter, many methods for its synthesis were reported. h-BN and r-BN are formed under ambient pressure. c-BN is synthesized from h-BN under high pressure at high temperature while w-BN is prepared from h-BN under high pressure at room temperature [1]. Each BN layer consists of stacks of hexagonal plate-like units of boron and nitrogen atoms linked by SP{sup 2} hybridized orbits and held together mainly by Van der Waals force (Fig 1(b)). The hexagonal polymorph has two-layered repeating units: AA'AA'... that differ from those in graphite: ABAB... (Figure 1(a)). Within the layers of h-BN there is coincidence between the same phases of the hexagons, although the boron atoms and nitrogen atoms are alternatively located along the c-axis. The rhombohedral system consists of three-layered units: ABCABC..., whose honeycomb layers are arranged in a shifted phase, like as those of graphite. Reflecting its weak interlayer bond, the h-BN can be cleaved easily along its layers, and hence, is widely used as a lubricant material. The material is stable up to a high temperature of 2300 C before decomposition sets in [2] does not fuse a nitrogen atmosphere of 1 atm, and thus, is applicable as a refractory material. Besides having such properties, similar to those of graphite, the material is transparent, and acts as a good electric insulator, especially at high temperatures (10{sup 6} {Omega}m at 1000 C) [1]. c-BN and w-BN are tetrahedrally linked BN. The former has a cubic sphalerite-type structure, and the latter has a hexagonal wurtzite-type structure. c-BN is the second hardest known material (the hardest is diamond), the so-called white diamond. It is used mainly for grinding and cutting industrial ferrous materials because it does not react with molten iron, nickel, and related alloys at high temperatures whereas diamond does [1]. It displays the second highest thermal conductivity (6-9 W/cm.deg) after diamond. This chapter focuses principally upon information about h-BN nanomaterials, mainly BN nanotubes (BNNTs), porous BN, mono- and few-layer-BN sheets. There are good reviews book chapters about c-BN in [1, 4-6].

Han,W.Q.

2008-08-01T23:59:59.000Z

177

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

E-Print Network (OSTI)

Zeolites ZSM-5 (SiO2/Al2O3=30~280) and Y(SiO2/Al2O3=5.2~80) are bound with silica gel (Ludox HS-40 and Ludox AS-40) and alumina (?- Al2O3 and boehmite) by different binding methods, namely, gel-mixing, powder-mixing and powder-wet-mixing methods. The acidities of the bound catalysts and the zeolite powder are determined by NH3-TPD and FTIR. The textures of these catalysts are analyzed on a BET machine with nitrogen as a probe molecule. The micropore surface area and micropore volume are determined by t-plot method. Micropore volume distribution is determined by Horvath-Kawazoe approach with a cylindrical pore model. Mesopore volume distribution is determined by BJH method from the nitrogen desorption isotherm. Silica from the binder may react with extra-framework alumina in zeolites to form a new protonic acid. SiO2-bound catalysts have less strong acidity, Bronsted acidity and Lewis acidity than the zeolite powder. Also, the strength of strong acid sites of the zeolites is reduced when silica is embedded. 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 and disproportionation) and ethylene oligomerization than ZSM-5 powder. When alumina is used as a binder, both the total acid sites and Lewis acid sites are increased. Micropore surface area and micropore volume of ZSM-5 powder are reduced by 26% and 23%, respectively, indicating some micropores of ZSM-5 are blocked by the alumina binder. Alumina-bound catalysts showed a lower activity for butane transformation and ethylene oligomerization than ZSM-5 powder. Alkaline metals content in the binder is a crucial factor that influences the acidity of a bound catalyst. The metal cations neutralize more selectively Bronsted acid sites than Lewis acid sites. Alkaline metal cations in the binder and micropore blockage cause the bound catalysts to have a lower catalytic activity than the zeolite powder.

Wu, Xianchun

2003-12-01T23:59:59.000Z

178

Daniela Rodica Radu  

Office of Scientific and Technical Information (OSTI)

Mesoporous silica nanomaterials for applications in catalysis, sensing, drug Mesoporous silica nanomaterials for applications in catalysis, sensing, drug delivery and gene transfection Daniela Rodica Radu A dissertation submitted to the graduate faculty in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Major: Chemistry Program of Study Committee: Victor Shang-Yi Lin, Major Professor William S. Jenks Marc D. Porter Nicola L. Pohl Brent H. Shanks Iowa State University Ames, Iowa 2004 Copyright 0 Daniela Rodica Radu, 2004. All rights reserved. .. 11 Graduate CoIlege Iowa State University This is to certify that the doctoral dissertation of Daniela Rodica Radu has met the dissertation requirements of Iowa State University For the Major Program ... 1 1 1 DEDICATION To my children "Float straight ahead and if the land you are looking for does not exist yet, be sure that God

179

Experimental characterisation of catalyst-free carbon nanomaterials from mixed vegetable and animal base oils through modified traditional process  

Science Conference Proceedings (OSTI)

A new process for the preparation of catalyst-free pure carbon nanomatereials is described here. These nanomaterials are then experimentally investigated. The process is simple and traditional so that the operator can have full control over the flame ...

P. S. Venkatanarayanan; R. Velmurugan; A. Joseph Stanley

2011-01-01T23:59:59.000Z

180

LIGHT SCATTERING STUDIES OF SILICA AEROGELS  

E-Print Network (OSTI)

S.S. , "Coherent Expanded Aerogels," J. of Phys. Chern.Production of Silica Aerogel," Physica Scripta 23, Nicolaon,S.J. , "Preparation des aerogels de silice a partir

Hunt, A.J.

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "mesoporous silica nanomaterials" 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

Silica-coated liposomes for insulin delivery  

Science Conference Proceedings (OSTI)

Liposomes coated with silica were explored as protein delivery vehicles for their enhanced stability and improved encapsulation efficiency. Insulin was encapsulated within the fluidic phosphatidylcholine lipid vesicles by thin film hydration at pH 2.5, ...

Neelam Dwivedi; M. A. Arunagirinathan; Somesh Sharma; Jayesh Bellare

2010-01-01T23:59:59.000Z

182

Mesoporous mixed metal oxides derived from P123-templated Mg-Al layered double hydroxides  

SciTech Connect

We report the preparation of mesoporous mixed metal oxides (MMOs) through a soft template method. Different amounts of P123 were used as structure directing agent to synthesize P123-templated Mg-Al layered double hydroxides (LDHs). After calcination of as-synthesized LDHs at 500 {sup o}C, the ordered mesopores were obtained by removal of P123. The mesoporous Mg-Al MMOs fabricated by using 2 wt% P123 exhibited a high specific surface area of 108.1 m{sup 2}/g, and wide distribution of pore size (2-18 nm). An investigation of the 'memory effect' of the mesoporous MMOs revealed that they were successfully reconstructed to ibuprofen intercalated LDHs having different gallery heights, which indicated different intercalation capacities. Due to their mesoporosity these unique MMOs have particular potential as drug or catalyst carriers. - Graphical abstract: Ordered mesoporous Mg-Al MMOs can be obtained through the calcination of P123-templated Mg-Al-CO{sub 3} LDHs. The pore diameter is 2.2 nm. At the presence of ibuprofen, the Mg-Al MMOs can recover to Mg-Al-IBU LDHs, based on its 'remember effect'. Display Omitted

Wang Jun, E-mail: zhqw1888@sohu.co [College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China); College of Chemical Engineering, Harbin Institute of Technology, Harbin 150001 (China); Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, 150001 (China); Zhou Jideng; Li Zhanshuang; He Yang; Lin Shuangshuang; Liu Qi [College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China); Zhang Milin [College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China); Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, 150001 (China); Jiang Zhaohua [College of Chemical Engineering, Harbin Institute of Technology, Harbin 150001 (China)

2010-11-15T23:59:59.000Z

183

Nanomaterials for Polymer Electrolyte Membrane Fuel Cells; Materials Challenges Facing Electrical Energy Storate  

SciTech Connect

Symposium T: Nanomaterials for Polymer Electrolyte Membrane Fuel Cells Polymer electrolyte membrane (PEM) fuel cells are under intense investigation worldwide for applications ranging from transportation to portable power. The purpose of this seminar is to focus on the nanomaterials and nanostructures inherent to polymer fuel cells. Symposium topics will range from high-activity cathode and anode catalysts, to theory and new analytical methods. Symposium U: Materials Challenges Facing Electrical Energy Storage Electricity, which can be generated in a variety of ways, offers a great potential for meeting future energy demands as a clean and efficient energy source. However, the use of electricity generated from renewable sources, such as wind or sunlight, requires efficient electrical energy storage. This symposium will cover the latest material developments for batteries, advanced capacitors, and related technologies, with a focus on new or emerging materials science challenges.

Gopal Rao, MRS Web-Editor; Yury Gogotsi, Drexel University; Karen Swider-Lyons, Naval Research Laboratory

2010-08-05T23:59:59.000Z

184

Nanomaterials ES&H | U.S. DOE Office of Science (SC)  

Office of Science (SC) Website

Research » National Research » National Nanotechnology Initiative (NNI) » Nanomaterials ES&H Basic Energy Sciences (BES) BES Home About Research Materials Sciences & Engineering (MSE) Chemical Sciences, Geosciences, and Biosciences (CSGB) Accelerator and Detector Research Research Conduct Policies DOE Energy Innovation Hubs Energy Frontier Research Centers National Nanotechnology Initiative (NNI) Nanomaterials ES&H Facilities Science Highlights Benefits of BES Funding Opportunities Basic Energy Sciences Advisory Committee (BESAC) News & Resources Contact Information Basic Energy Sciences U.S. Department of Energy SC-22/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301) 903-3081 F: (301) 903-6594 E: sc.bes@science.doe.gov More Information » National Nanotechnology Initiative (NNI)

185

CFN Operations and Safety Awareness (COSA) Checklist Soft-Bio Nanomaterials Facility  

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

Soft-Bio Nanomaterials Facility Soft-Bio Nanomaterials Facility Building 735 This COSA form must be completed for all experimenters working in the CFN and must be submitted to the CFN User Office for badge access. CFN Safety Awareness Policy: Each user must be instructed in the safe procedures in CFN related activities. CFN Facility Laboratory personnel shall keep readily available all relevant instructions and safety literature. Employee/Guest Name Life/Guest Number Department/Division ES&H Coordinator/Ext. Facility Manager COSA Trainer Guest User Staff USER ADMINISTRATION Checked in at User Administration and has valid BNL ID badge Safety Approval Form (SAF) approved. Training requirements completed (Indicate additional training specified in SAF or ESR in lines provided below):

186

Quarterly Report: Microchannel-Assisted Nanomaterial Deposition Technology for Photovoltaic Material Production  

DOE Green Energy (OSTI)

Quarterly report to ITP for Nanomanufacturing program. Report covers FY11 Q2. The primary objective of this project is to develop a nanomanufacturing process which will reduce the manufacturing energy, environmental discharge, and production cost associated with current nano-scale thin-film photovoltaic (PV) manufacturing approaches. The secondary objective is to use a derivative of this nanomanufacturing process to enable greener, more efficient manufacturing of higher efficiency quantum dot-based photovoltaic cells now under development. The work is to develop and demonstrate a scalable (pilot) microreactor-assisted nanomaterial processing platform for the production, purification, functionalization, and solution deposition of nanomaterials for photovoltaic applications. The high level task duration is shown. Phase I consists of a pilot platform for Gen II PV films along with parallel efforts aimed at Gen III PV quantum dot materials. Status of each task is described.

Palo, Daniel R.

2011-04-26T23:59:59.000Z

187

A New Concept for the Fabrication of Hydrogen Selective Silica Membranes  

DOE Green Energy (OSTI)

It is attempted to synthesize hydrogen selective silica-based membranes through a novel thin film deposition concept. This report describes the progress made during the 1st Year of this award. All project Tasks, for Year 1, were completed and the first thin films were prepared and characterized. The goal of this work is to use crystalline layered silicates to form hydrogen selective membranes for use in high temperature hydrogen/carbon dioxide separations. It was proposed to: (A) Synthesize layered silicate materials; (B) Prepare dispersions of as synthesized or delaminated layered silicates; (C) Prepare membranes by coating the layered silicates on macro-mesoporous supports; and (D) Test the membranes for H{sub 2}/CO{sub 2} selectivity at high temperature and pressures and for structural and functional stability at high temperature in the presence of water vapor. All Year 1 project Tasks are completed. Layered silicate particles were synthesized hydrothermally. Crystal shape and size was optimized for the formation of thin films. Calcination procedures that avoid particle agglomeration were developed and suspensions of the calcined silicate particles were prepared. The silicate particles and suspensions were characterized by X-Ray Diffraction, Electron Microscopy and Dynamic Light Scattering. The characterization data indicate that plate like morphology, large aspect ratio and good dispersion have been achieved. A deposition process that leads to uniform, high-coverage ({approx}100%) coating of the layered silicate particles on porous alpha-alumina supports was developed.

Michael Tsapatsis

2005-10-01T23:59:59.000Z

188

Final Report: Nanomaterials in Secondary Battery Research and Development, July 1, 1995 - September 14, 1999  

DOE Green Energy (OSTI)

We have been exploring the rate capabilities of nanostructured Li-ion battery electrodes. These nanostructured electrodes are prepared via the template method - a general procedure used to prepare nanomaterials pioneered in the P.I.'s laboratory. The nanostructured electrodes consist of nanofibers or tubules of the electrode material that protrude from a current-collector surface like the bristles of a brush. These nanostructured electrodes show dramatically improved rate capabilities relative to conventional electrode designs.

Martin, Charles R.

2000-01-31T23:59:59.000Z

189

Chemistry of silica in Cerro Prieto brines  

DOE Green Energy (OSTI)

The precipitation of amorphous silica from synthetic geothermal brines which resemble the flashed brine at Cerro Prieto has been studied. It was found that part of the dissolved silica quickly polymerizes to form suspended colloidal silica. The colloidal silica flocculates and settles slowly at unmodified brine pH values near 7.35. Raising the pH of the brine to about 7.8 by adding base and stirring for a few minutes causes rapid and complete flocculation and settling. These results have been confirmed in the field using actual Cerro Prieto brine. Both in the laboratory and in the field quaternary amines were found to be effective with some brine compositions but not with others. Polyacrylamides do not work at all. These results suggest the following simple preinjection brine treatment process: age the brine for 10 to 20 minutes in a covered holding tank, add 20 to 30 ppM lime (CaO), stir for 5 minutes, and separate the flocculated silica from the brine using a conventional clarifier. The brine coming out of such a process will be almost completely free of suspended solids. The pilot plant tests needed to reduce this conceptual process to practice are discussed. The rate of deposition of silica scale from synthetic brines was separately studied. It was found that a modest decrease in pH could significantly reduce the scaling rate at a reasonable cost. The equilibrium chemistry of Cerro Prieto brine was studied theoretically. These calculations indicate that increasing the brine pH to remove silica might cause some precipitation of carbonate minerals, but also that this problem could easily be eliminated at a reasonable cost if it did arise.

Weres, O.; Tsao, L.; Iglesias, E.

1980-04-01T23:59:59.000Z

190

Chemistry of Silica in Cerro Prieto Brines  

DOE Green Energy (OSTI)

The precipitation of amorphous silica from synthetic geothermal, brines which resemble the flashed brine at Cerro Prieto has been studied. It was found that part of the dissolved silica quickly polymerizes to form suspended colloidal silica. The colloidal silica flocculates and settles slowly at unmodified brine pH values near 7.35. Raising the pH of the brine to about 7.8 by adding base and stirring for a few minutes causes rapid and complete flocculation and settling. these results have been confirmed in the field using actual Cerro Prieto brine. Both in the laboratory and in the field quaternary amines were found to be effective with some brine compositions but not with others. Polyacrylamides do not work at all. These results suggest the following simple preinjection brine treatment process: age the brine for 10-20 minutes in a covered holding tank, add 20-30 ppm lime (CaO), stir for 5 minutes, and separate the flocculated silica from the brine using a conventional clarifier. The brine coming out of such a process will be almost completely free of suspended solids. The pilot plant tests needed to reduce this conceptual process to practice are discussed. The rate of deposition of silica scale from synthetic brines was separately studied. It was found that a modest decrease in pH could significantly reduce the scaling rate at a reasonable cost. The equilibrium chemistry of Cerro Prieto brine was studied theoretically. These calculations indicate that increasing the brine pH to remove silica might cause some precipitation of carbonate minerals, but also that this problem could easily be eliminated at a reasonable cost if it did arise.

Weres, Oleh; Iglesias, Eduardo; Tsao, Leon

1980-04-01T23:59:59.000Z

191

Mesoporous TiO2 spheres with a nitridated conducting layer  

Science Conference Proceedings (OSTI)

Nitridated TiO2 mesoporous spheres have been synthesized by hydrothermal processing followed by post-nitridation with NH3. Characterization data reveal a nitridated conducting layer, in addition to a mesoporous, and nanosized building-block morphology resulting in a large surface area. The samples have an average pore size and surface area of, respectively, 10 nm and 87 m2/g. The nitridated TiO2 mesoporous spheres exhibit a high capacity of > 200 mAh/g with good cyclability and high rate capability, as the nitridated conducting layer and favorable morphology of nanosized spheres provides good electrical contact, accommodates cycling induced strain smoothly, and facilitates lithium-ion diffusion.

Yoon, Sukeun [ORNL; Bridges, Craig A [ORNL; Unocic, Raymond R [ORNL; Paranthaman, Mariappan Parans [ORNL

2013-01-01T23:59:59.000Z

192

High resolution patterning of silica aerogels  

SciTech Connect

Three-dimensional metallic structures are fabricated with high spatial resolution in silica aerogels. In our method, silica hydrogels are prepared with a standard base-catalyzed route, and exchanged with an aqueous solution typically containing Ag{sup +} ions (1 M) and 2-propanol (0.2 M). The metal ions are reduced photolytically with a table-top ultraviolet lamp, or radiolytically, with a focused X-ray beam. We fabricated dots and lines as small as 30 x 70 {micro}m, protruding for several mm into the bulk of the materials. The hydrogels are eventually supercritically dried to yield aerogels, without any measurable change in the shape and spatial resolution of the lithographed structures. Transmission electron microscopy shows that illuminated regions are composed by Ag clusters with a size of several {micro}m, separated by thin layers of silica.

Bertino, M.F.; Hund, J.F.; Sosa, J.; Zhang, G.; Sotiriou-Leventis, C.; Leventis, N.; Tokuhiro, A.T.; Terry, J. (UMR-MUST); (IIT)

2008-10-30T23:59:59.000Z

193

Measurement of muonium emission from silica aerogel  

E-Print Network (OSTI)

Emission of muonium ($\\mu^{+}e^{-}$) atoms from silica aerogel into vacuum was observed. Characteristics of muonium emission were established from silica aerogel samples with densities in the range from 29 mg cm$^{-3}$ to 178 mg cm$^{-3}$. Spectra of muonium decay times correlated with distances from the aerogel surfaces, which are sensitive to the speed distributions, follow general features expected from a diffusion process, while small deviations from a simple room-temperature thermal diffusion model are identified. The parameters of the diffusion process are deduced from the observed yields.

Bakule, P; Contreras, D; Esashi, M; Fujiwara, Y; Fukao, Y; Hirota, S; Iinuma, H; Ishida, K; Iwasaki, M; Kakurai, T; Kanda, S; Kawai, H; Kawamura, N; Marshall, G M; Masuda, H; Matsuda, Y; Mibe, T; Miyake, Y; Okada, S; Olchanski, K; Olin, A; Onishi, H; Saito, N; Shimomura, K; Strasser, P; Tabata, M; Tomono, D; Ueno, K; Yokoyama, K; Yoshida, S

2013-01-01T23:59:59.000Z

194

Measurement of muonium emission from silica aerogel  

E-Print Network (OSTI)

Emission of muonium ($\\mu^{+}e^{-}$) atoms from silica aerogel into vacuum was observed. Characteristics of muonium emission were established from silica aerogel samples with densities in the range from 29 mg cm$^{-3}$ to 178 mg cm$^{-3}$. Spectra of muonium decay times correlated with distances from the aerogel surfaces, which are sensitive to the speed distributions, follow general features expected from a diffusion process, while small deviations from a simple room-temperature thermal diffusion model are identified. The parameters of the diffusion process are deduced from the observed yields.

P. Bakule; G. A. Beer; D. Contreras; M. Esashi; Y. Fujiwara; Y. Fukao; S. Hirota; H. Iinuma; K. Ishida; M. Iwasaki; T. Kakurai; S. Kanda; H. Kawai; N. Kawamura; G. M. Marshall; H. Masuda; Y. Matsuda; T. Mibe; Y. Miyake; S. Okada; K. Olchanski; A. Olin; H. Onishi; N. Saito; K. Shimomura; P. Strasser; M. Tabata; D. Tomono; K. Ueno; K. Yokoyama; S. Yoshida

2013-06-17T23:59:59.000Z

195

Safety Bulletin 2007-08 Silica Dust Exposure  

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

minerals. Potential work exposure to airborne crystalline silica includes abrasive blasting, sandblasting, rock cutting, chipping, drilling, grinding, jack hammering, concrete...

196

A threshold Cherenkov detector for K separation using silica aerogel  

E-Print Network (OSTI)

A threshold Cherenkov detector for Kþ =pþ separation using silica aerogel R. Siudak a,b , A August 2008 Keywords: Threshold Cherenkov detector Silica aerogel Reaction pp ! Kþ ðLp� Kþ =pþ separation in the focal plane of a magnetic spectrograph. Silica aerogel with refractive index of n ¼ 1:05 is applied

Magiera, Andrzej

197

Raspberry derived mesoporous carbon-tubules and fixed-bed adsorption of pharmaceutical drugs  

E-Print Network (OSTI)

Raspberry derived mesoporous carbon-tubules and fixed-bed adsorption of pharmaceutical drugs Shashi 210023, China c Laboratory of Green Chemistry, Lappeenranta University of Technology, Sammonkatu 12 Department, University of Florida, Gainesville, FL 32611-0290, USA 1. Introduction Pharmaceutical drugs (PD

Ma, Lena

198

Characterization of vanadium/silica and copper/silica aerogel catalysts  

DOE Green Energy (OSTI)

Vanadium/silica and copper/silica aerogels have been prepared using the sol-gel method followed by CO{sub 2} exchange and supercritical extraction. Structural properties of samples supercritically dried, oxidized and used in reactions studies conducted with a feed representing the average composition of automobile exhaust from a lean burn engine were investigated using laser Raman spectroscopy and temperature-programmed reduction. No evidence of crystalline V{sub 2}O{sub 5} was found for the vanadium/silica aerogel, freshly extracted, oxidized or following exposure to reaction conditions using these techniques. However, results obtained for the copper/silica sample indicate that changes in the structure of the copper species had occurred as the sample was oxidized and exposed to reaction conditions.

Owens, L.; Tillotson, T.M.; Hair, L.M. [Lawrence Livermore National Lab., CA (United States). Chemistry and Materials Science Dept.

1995-09-01T23:59:59.000Z

199

Molecular sieving silica membrane fabrication process  

DOE Patents (OSTI)

A process is described 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. 11 figs.

Raman, N.K.; Brinker, C.J.

1999-08-10T23:59:59.000Z

200

Moisture transport in silica gel particle beds  

DOE Green Energy (OSTI)

A theoretical and experimental study of the performance of silica gel packed particle beds is described. A bench-scale test rig was used to obtain data for parameter values pertinent to solar air-conditioning applications. Both adsorption and desorption experiments were performed for Regular Density (RD) silica gel for a wide range of particle size. Adsorption data were also obtained for Intermediate Density (ID) gel. A model of heat and mass transfer in the bed was developed with special attention paid to the modeling of solid side resistance. For this latter purpose an extensive review of the available literature on moisture adsorption and moisture transport in silica gel was made. Both Knudsen and surface diffusion are found to be important mechanisms of moisture transport in Intermediate Density gels while surface diffusion is dominant in Regular Density gels. A general equation for moisture transport in a spherical silica gel particle was developed and was incorporated into the model equations governing heat and mass transfer between the gel particles and air flowing through a packed particle bed. A computer code DESICCANT was written to solve the coupled set of partial differential equations using a finite difference numerical method. The agreement between theory and experiment for adsorption on RD gel is satisfactory, and is somewhat better for the outlet water vapor concentration than for the outlet air temperature. The agreement for desorption from RD gel and adsorption to ID gel is satisfactory, but not as good as for adsorption on RD gel.

Pesaran, A.A.

1983-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "mesoporous silica nanomaterials" 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

Significant Silica Solubility in Geothermal Steam  

DOE Green Energy (OSTI)

Although it is widely believed that silica solubility in low pressure (5 to 10 bar) geothermal steam is negligible, when one takes into account steam flows exceeding 10 million tonnes a year--at Wairakei, for instance--it is found that the amount transmitted in the vapor has the potential to give significant deposits on turbine nozzles and blades. A 150 MWe power station, when based on flows from a hot water reservoir at (a) 250 C or (b) 315 C, and with separator pressures of 6 bar, is found to carry about 100 and 200 kg/year respectively in the steam phase. In the case of a similar sized station exploiting a dry steam reservoir such as The Geysers, equivalent silica flows are obtained, dissolved in steam and carried as dust--the latter as solid particles precipitating from the vapor en route from source to turbine, and not preexisting in the formations as is commonly considered. Choking or coating of subterranean rock near such dry steam wells due to exsolving silica, may be the principal cause of declining steam discharge under production. Silica from completely dry or superheated steam can also seal the cap and sides of steam reservoirs when expanding below the criticus temperature (236 C) in a way previously thought possible only by hot water or wet steam.

James, Russell

1986-01-21T23:59:59.000Z

202

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

203

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

204

Carbon spheres-assisted strategy to prepare mesoporous manganese dioxide for supercapacitor applications  

Science Conference Proceedings (OSTI)

Mesoporous MnO{sub 2} microstructures with large specific surface area have been successfully synthesized by an in-situ redox precipitation method in the presence of colloidal carbon spheres. The samples of them had much higher specific surface area, pore size and pore volume than those obtained via routes without carbon spheres. The morphology, chemical compositions and porous nature of products were fully characterized. Electrochemical measurements showed that these mesoporous MnO{sub 2} could function well when used as positive electrode materials for supercapacitor. Ideal electrochemical capacitive performances and cyclic stability after 2000 galvanostatic charge-discharge cycles could be observed in 1 M neutral Na{sub 2}SO{sub 4} aqueous electrolyte with a working voltage of 1.7 V. - Graphical Abstract: Mesoporous MnO{sub 2} microstructures with large S{sub BET} were successfully synthesized by in-situ redox precipitation method in the presence of colloidal carbon spheres. Electrochemical measurements showed that these mesoporous MnO{sub 2} could be well used as electrode materials for supercapacitor. Highlights: Black-Right-Pointing-Pointer Mesoporous MnO{sub 2} was prepared by in-situ redox method assisted by carbon spheres. Black-Right-Pointing-Pointer S{sub BET}, pore size and volume were higher than MnO{sub 2} obtained without carbon spheres. Black-Right-Pointing-Pointer They could function well when used as electrode materials for supercapacitor. Black-Right-Pointing-Pointer Ideal capacitive behaviors and long cycling life showed after 2000 charge-discharge.

Li Siheng [State Key Laboratory of Electroanalytical Chemistry, and Jilin Provincial Key Laboratory of Advanced Low-carbon Chemical Power, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin St., Changchun 130022 (China); Graduate University of Chinese Academy of Sciences, Beijing 100039 (China); Qi Li, E-mail: qil@ciac.jl.cn [State Key Laboratory of Electroanalytical Chemistry, and Jilin Provincial Key Laboratory of Advanced Low-carbon Chemical Power, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin St., Changchun 130022 (China); Lu Lehui; Wang Hongyu [State Key Laboratory of Electroanalytical Chemistry, and Jilin Provincial Key Laboratory of Advanced Low-carbon Chemical Power, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin St., Changchun 130022 (China)

2013-01-15T23:59:59.000Z

205

Low-Temperature Fluorination of Soft-Templated Mesoporous Carbons for a High-Power Lithium/Carbon Fluoride Battery  

Science Conference Proceedings (OSTI)

Soft-templated mesoporous carbons and activated mesoporous carbons were fluorinated using elemental fluorine between room temperature and 235 C. The mesoporous carbons were prepared via self-assembly synthesis of phloroglucinol formaldehyde as a carbon precursor in the presence of triblock ethylene oxide propylene oxide ethylene oxide copolymer BASF Pluronic F127 as the template. The F/C ratios ranged from 0.15 to 0.75 according to gravimetric, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy analysis. Materials have mesopore diameters up to 11 nm and specific surface areas as high as 850 m2 g 1 after fluorination as calculated from nitrogen adsorption isotherms at 196 C. Furthermore, the materials exhibit higher discharge potentials and energy and power densities as well as faster reaction kinetics under high current densities than commercial carbon fluorides with similar fluorine contents when tested as cathodes for Li/CFx batteries.

Fulvio, Pasquale F [ORNL; Dai, Sheng [ORNL; Guo, Bingkun [ORNL; Mahurin, Shannon Mark [ORNL; Mayes, Richard T [ORNL; Sun, Xiao-Guang [ORNL; Veith, Gabriel M [ORNL; Brown, Suree [ORNL; Adcock, Jamie [University of Tennessee, Knoxville (UTK)

2011-01-01T23:59:59.000Z

206

Conversion of geothermal waste to commercial products including silica  

DOE Patents (OSTI)

A process for the treatment of geothermal residue includes contacting the pigmented amorphous silica-containing component with a depigmenting reagent one or more times to depigment the silica and produce a mixture containing depigmented amorphous silica and depigmenting reagent containing pigment material; separating the depigmented amorphous silica and from the depigmenting reagent to yield depigmented amorphous silica. Before or after the depigmenting contacting, the geothermal residue or depigmented silica can be treated with a metal solubilizing agent to produce another mixture containing pigmented or unpigmented amorphous silica-containing component and a solubilized metal-containing component; separating these components from each other to produce an amorphous silica product substantially devoid of metals and at least partially devoid of pigment. The amorphous silica product can be neutralized and thereafter dried at a temperature from about 25.degree. C. to 300.degree. C. The morphology of the silica product can be varied through the process conditions including sequence contacting steps, pH of depigmenting reagent, neutralization and drying conditions to tailor the amorphous silica for commercial use in products including filler for paint, paper, rubber and polymers, and chromatographic material.

Premuzic, Eugene T. (East Moriches, NY); Lin, Mow S. (Rocky Point, NY)

2003-01-01T23:59:59.000Z

207

Vol. 63 No. 1 JOM 43www.tms.org/jom.html CommentaryNanomaterials for Renewable Energy  

E-Print Network (OSTI)

Vol. 63 No. 1 · JOM 43www.tms.org/jom.html CommentaryNanomaterials for Renewable Energy Fernand D be placed on achieving higher energy efficiency and increasing supplies from all forms of renewable energy Systems in Energy and Environment: Renewable Energy Fernand D.S. Marquis ence include (1) dimensional

208

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

209

Nanomaterials: Energy  

Science Conference Proceedings (OSTI)

Feb 28, 2011... by Sandia Corp., a wholly owned subsidiary of Lockheed Martin Co., for the U.S. DOE's NNSA under contract DE-AC04-94AL85000. 3:20 PM

210

Carbon Nanomaterials  

Science Conference Proceedings (OSTI)

Mar 4, 2013 ... Graphene-based materials are promising because of their electronic/thermal transport, mechanical properties, large surface area, and that they ...

211

Carbon Nanomaterials  

Science Conference Proceedings (OSTI)

Mar 12, 2012 ... The graphene film was spin-coated using carbon nanotubes to form the cathode of the field emission device. A phosphor coated graphene-PET ...

212

Synthesis of Novel Polypeptide-Silica Hybrid Materials through Surface-Initiated N-carboxyanhydride Polymerization  

E-Print Network (OSTI)

There is an increasing demand for materials that are physically robust, easily recovered, and able to perform a wide variety of chemical functions. By combining hard and soft matter synergistically, organic-inorganic hybrid materials are potentially useful for a number of applications (e.g. catalysis, separations, sensing). In this respect, organic/ordered mesoporous silica (OMS) hybrids have attracted considerable attention, with an increasing emphasis on complex organic moieties achieved through multi-step reactions and polymerizations. It is on this front that we have focused our work, specifically in regard to polypeptides. Polypeptides are well suited organic components for hybrids as they provide a wide range of possible side chain chemistries (NH2, -SH, -COOH, -OH, etc.), chirality, and have conformations that are known to be responsive to external stimuli (pH, electrolytes, solvents, etc.). Our work has shown that N-carboxyanhydride chemistry offers a facile single step approach to the incorporation of dense polypeptide brushes in OMS. Modifying the initiator loading, pore size, pore topology, and monomer identity significantly impacted the properties of the obtained composites and peptide brush layers. Extending this work, a synthesis paradigm for preferentially grafting poly-L-lysine to the external and internal surfaces of SBA-15, a widely used OMS material, was developed. We observed that the pores of these hybrids could be opened and closed by the reversible swelling of the polypeptide layer. Similarly, novel bifunctional hybrids were synthesized by grafting polypeptides to the external surface of monodisperse OMS spheres that contain a thiol-functionalized core. The accessibility of the internal thiols to a fluorescent dye shows the potential of these hybrids for applications such as controlled uptake/release.

Lunn, Jonathan D.

2010-05-01T23:59:59.000Z

213

Nanomaterials from Aerosols Aerosols are suspensions of liquid or solid particles in a gas. Aerosol particles  

E-Print Network (OSTI)

arid regions in China and Africa. Such aerosol streams have been shown to travel around the globe with silica aerosols from China impacting air quality in the continental US and #12;2 alumina and titania delivery mechanisms for a variety of drugs as an alternative to injections. As delivery devices

Beaucage, Gregory

214

Recent progress in silica aerogel Cherenkov radiator  

E-Print Network (OSTI)

In this paper, we present recent progress in the development of hydrophobic silica aerogel as a Cherenkov radiator. In addition to the conventional method, the recently developed pin-drying method for producing high-refractive-index aerogels with high transparency was studied in detail. Optical qualities and large tile handling for crack-free aerogels were investigated. Sufficient photons were detected from high-performance aerogels in a beam test.

Tabata, Makoto; Kawai, Hideyuki; Kubo, Masato; Sato, Takeshi

2012-01-01T23:59:59.000Z

215

Mesoporous carbon -Cr2O3 composite as an anode material for lithium ion batteries  

SciTech Connect

Mesoporous carbon-Cr2O3 (M-C-Cr2O3) composite was prepared by co-assembly of in-situ formed phenolic resin, chromium precursor, and Pluronic block copolymer under acidic conditions, followed by carbonization at 750oC under Argon. The TEM results confirmed that the Cr2O3 nanoparticles, ranging from 10 to 20 nm, were well dispersed in the matrix of mesoporous carbon. The composite exhibited an initial reversible capacity of 710 mAh g-1 and good cycling stability, which is mainly due to the synergic effects of carbons within the composites, i.e. confining the crystal growth of Cr2O3 during the high temperature treatment step and buffering the volume change of Cr2O3 during the cycling step. This composite material is a promising anode material for lithium ion batteries.

Guo, Bingkun [ORNL; Chi, Miaofang [ORNL; Sun, Xiao-Guang [ORNL; Dai, Sheng [ORNL

2012-01-01T23:59:59.000Z

216

Mesoporous TiO2-B Microspheres with Superior Rate Performance for Lithium Ion Batteries  

SciTech Connect

Mesoporous TiO2-B microsperes with a favorable material architecture are designed and synthesized for high power lithium ion batteries. This material, combining the advantages of fast lithium transport with a pseudocapacitive mechanism, adequate electrode-electrolyte contact and compact particle packing in electrode layer, shows superior high-rate charge-discharge capability and long-time cyclability for lithium ion batteries.

Liu, Hansan [ORNL; Bi, Zhonghe [ORNL; Sun, Xiao-Guang [ORNL; Unocic, Raymond R [ORNL; Paranthaman, Mariappan Parans [ORNL; Dai, Sheng [ORNL; Brown, Gilbert M [ORNL

2011-01-01T23:59:59.000Z

217

Synthesis of mesoporous NiO doped TiO{sub 2} submicrosphere via spray hydrolysis  

Science Conference Proceedings (OSTI)

NiO doped TiO{sub 2} submicrosphere have been prepared via spray hydrolysis. The doping concentration has been varied form 2 wt% to 15 wt%. Morphology of the submicrospheres has been investigated using small-angle neutron scattering and scanning electron microscopy. Elemental analysis has been carried out by energy dispersive X-ray analysis which confirms the doping concentrations. The mesopores in submicrospheres possess cylindrical morphology.

Bahadur, J.; Sen, D.; Prakash, J.; Singh, Ripandeep; Paul, B.; Mazumder, S.; Sathiyamoorthy, D. [Solid State Physics Division Bhabha Atomic Research Centre, Mumbai, 400085, India (India); Powder Metallurgy Division Bhabha Atomic Research Centre, Mumbai, 400085 (India); Solid State Physics, Division Bhabha Atomic Research Centre, Mumbai, 400085 (India); Materials Processing Division Bhabha Atomic Research Centre, Mumbai, 400085 (India); Solid State Physics Division Bhabha Atomic Research Centre, Mumbai, 400085 (India); Powder Metallurgy Division Bhabha Atomic Research Centre, Mumbai, 400085 (India)

2012-06-05T23:59:59.000Z

218

Taking a Page from Nature to Build Better Nanomaterials | Advanced Photon  

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

Hard as Diamond: A New Form of Carbon Created under Ultrahigh Pressure Hard as Diamond: A New Form of Carbon Created under Ultrahigh Pressure How Algae Use a "Sulfate Trap" to Selectively Biomineralize Strontium Emulating-and Surpassing-Nature Reducing Stress in Multilayer Laue Lenses Novel Magnetic Material Operates under Extreme Stress Conditions Science Highlights Archives: 2013 | 2012 | 2011 | 2010 2009 | 2008 | 2007 | 2006 2005 | 2004 | 2003 | 2002 2001 | 2000 | 1998 | Subscribe to APS Science Highlights rss feed Taking a Page from Nature to Build Better Nanomaterials OCTOBER 26, 2011 Bookmark and Share Fig. 1. Grazing incidence diffraction data revealing the interface structure of alkylthiol Langmuir monolayer (left) and the gold nanocrystals (right) simultaneously. Sometimes nature cannot be improved upon. One example is in the synthesis

219

Computational Design of Self-Assembling Protein Nanomaterials with Atomic Level Accuracy  

SciTech Connect

We describe a general computational method for designing proteins that self-assemble to a desired symmetric architecture. Protein building blocks are docked together symmetrically to identify complementary packing arrangements, and low-energy protein-protein interfaces are then designed between the building blocks in order to drive self-assembly. We used trimeric protein building blocks to design a 24-subunit, 13-nm diameter complex with octahedral symmetry and a 12-subunit, 11-nm diameter complex with tetrahedral symmetry. The designed proteins assembled to the desired oligomeric states in solution, and the crystal structures of the complexes revealed that the resulting materials closely match the design models. The method can be used to design a wide variety of self-assembling protein nanomaterials.

King, Neil P.; Sheffler, William; Sawaya, Michael R.; Vollmar, Breanna S.; Sumida, John P.; André, Ingemar; Gonen, Tamir; Yeates, Todd O.; Baker, David (UWASH); (UCLA); (HHMI); (LIT)

2012-10-24T23:59:59.000Z

220

The electrochemical performance of ordered mesoporous carbon/nickel compounds composite material for supercapacitor  

SciTech Connect

A series of high performance ordered mesoporous carbon/nickel compounds composites have been synthesized by a combination of incipient wetness impregnation and hydrothermal method for the first time. X-ray diffraction (XRD), N{sub 2} adsorption/desorption isotherms and transmission electron microscopy (TEM) are used to characterize the composites derived at the hydrothermal temperature of 125, 150, 175, 200, 250, 275 and 300 {sup o}C. The formation of nanosized nickel compounds, fully inside the mesopore system, was confirmed with XRD and TEM. An N{sub 2} adsorption/desorption isotherms measurements still revealed mesoporosity for the host/guest compounds. It is noteworthy that an OMC/nickel nitrate hydroxide hydrate composite (OMCN-150) exhibits more excellent performance. Based on the various hydrothermal temperatures of the composite, the capacitance of an OMCN-150 delivering the best electrochemical performance is about 2.4 (5 mV s{sup -1}) and 1.5 (50 mV s{sup -1}) times of the pristine OMC. The capacitance retention of an OMCN-150 is 96.1%, which indicates that the electrochemical performance of the supercapacitor is improved greatly, and represents novel research and significant advances in the field of electrode composite materials for supercapacitor. -- Graphical abstract: A series of high performance nickel compound/ordered mesoporous carbon composites were synthesized by a combination of incipient wetness impregnation and hydrothermal method for the first time. Display Omitted

Feng, Jicheng; Zhao, Jiachang; Tang, Bohejin; Liu, Ping [College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, Shanghai 201620 (China); Xu, Jingli, E-mail: jinglixu@sues.edu.c [College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, Shanghai 201620 (China)

2010-12-15T23:59:59.000Z

Note: This page contains sample records for the topic "mesoporous silica nanomaterials" 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

Nitrogen-Doped Mesoporous Carbon for Carbon Capture A Molecular Simulation Study  

Science Conference Proceedings (OSTI)

Using molecular simulation, we investigate the effect of nitrogen doping on adsorption capacity and selectivity of CO{sub 2} versus N{sub 2} in model mesoporous carbon. We show that nitrogen doping greatly enhances CO{sub 2} adsorption capacity; with a 7 wt % dopant concentration, the adsorption capacity at 1 bar and 298 K increases from 3 to 12 mmol/g (or 48% uptake by weight). This great enhancement is due to the preferred interaction between CO{sub 2} and the electronegative nitrogen. The nitrogen doping coupled with the mesoporosity also leads to a much higher working capacity for adsorption of the CO{sub 2}/N{sub 2} mixture in nitrogen-doped mesoporous carbon. In addition, the CO{sub 2}/N{sub 2} selectivity is almost 5 times greater than in nondoped carbon at ambient conditions. This work indicates that nitrogen doping is a promising strategy to create mesoporous carbons for high-capacity, selective carbon capture.

Babarao, Ravichandar [ORNL; Dai, Sheng [ORNL; Jiang, Deen [ORNL

2012-01-01T23:59:59.000Z

222

Dynamic performance characterization of bound, porous silica gel desiccant  

DOE Green Energy (OSTI)

Drying of air with silica gel is a well established procedure. However, for the specific use of silica gel in a novel desiccant air conditioning system, which continually cools the silica gel and utilizes solar energy for silica gel regeneration, conventional packed bed devices are not suitable. For this system to operate effectively the silica gel must not rise in its temperature or its capacity will be greatly diminished. Dynamic dehumidificatuion performance was investigted for a silica gel desiccant fabricated in bound, porous paper-like sheets. Sheets of various thickness (0.7 to 3 mm) were fabricated and tested under several dynamic flow conditions in a flat rectangular channel apparatus. During each experiment conditions of inlet moisture, air flowrate, and sheet temperature were maintained constant. Comparisons were also made with conventional silica gel pellets and with other forms of bound silica gel. The sheets show superior utilization of silica gel in short times (30 minutes or less). Tests were also made to examine the sheet structure in order to explore the effect of temperature on the porous structure, and to obtain pore size distributions.

Onischak, M.; Gidaspow, D.; Perkari, S.; Sasaki, T.

1979-10-01T23:59:59.000Z

223

Heat Transfer through Materials: Application to Silica Aerogels...  

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

Heat Transfer through Materials: Application to Silica Aerogels and Building Envelopes Speaker(s): Brangre Lartigue Date: December 19, 2005 - 12:00pm Location: Bldg. 90 After...

224

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

225

Dual-Layer Asymmetric Microporous Silica Membranes  

DOE Green Energy (OSTI)

We report a novel sol-gel dip-coating process to form dual-layer microporous silica membranes with improved membrane performance and reproducibility. First, we deposit a surfactant-templated silica (STS) intermediate layer on top of a commercial {gamma}-alumina support both to improve its ''surface finish'' and to prevent a subsequently deposited microporous overlayer from penetrating into the support. Second, membranes are processed under clean room conditions to avoid dust contamination and, third, membranes are vacuum-calcined to promote further pore shrinkage and impart surface hydrophobicity. The resulting asymmetric membrane exhibits a gradual change in pore diameter from 50{angstrom} ({gamma}-alumina support layer) to 10-12{angstrom} (STS intermediate layer), and then to 3-4{angstrom} (30nm thick, ultramicroporous silica top-layer). Compared to a single-layer process using only the microporous overlayer, the dual-layer process improves both flux and selectivity. For the industrially important problem of natural gas purification, the combined CO{sub 2} flux [(3{approx} 0.5) x 10{sup {minus}4} cm{sup 3}(STP)/(s{center_dot}cm{sup 2}{center_dot}cm-Hg)] and CO{sub 2}/CH{sub 4} separation factors [200{approx}600] are superior to all previously reported values for separation of a 50/50 (v/v) CO{sub 2}/CH{sub 4} gas mixture. In addition, the membrane selectively separated hydrogen from a simulated reformate from partial oxidation of methanol as evidenced by a high concentration of hydrogen recovery.

TSAI,CHUNG-YI; TAM,SIU-YUE; LU,YUNFENG; BRINKER,C. JEFFREY

1999-11-19T23:59:59.000Z

226

Hydrophobic silica aerogel production at KEK  

E-Print Network (OSTI)

We present herein a characterization of a standard method used at the High Energy Accelerator Research Organization (KEK) to produce hydrophobic silica aerogels and expand this method to obtain a wide range of refractive index (n = 1.006-1.14). We describe in detail the entire production process and explain the methods used to measure the characteristic parameters of aerogels, namely the refractive index, transmittance, and density. We use a small-angle X-ray scattering (SAXS) technique to relate the transparency to the fine structure of aerogels.

Tabata, Makoto; Kawai, Hideyuki; Sumiyoshi, Takayuki; Yokogawa, Hiroshi

2011-01-01T23:59:59.000Z

227

Hydrophobic silica aerogel production at KEK  

E-Print Network (OSTI)

We present herein a characterization of a standard method used at the High Energy Accelerator Research Organization (KEK) to produce hydrophobic silica aerogels and expand this method to obtain a wide range of refractive index (n = 1.006-1.14). We describe in detail the entire production process and explain the methods used to measure the characteristic parameters of aerogels, namely the refractive index, transmittance, and density. We use a small-angle X-ray scattering (SAXS) technique to relate the transparency to the fine structure of aerogels.

Makoto Tabata; Ichiro Adachi; Hideyuki Kawai; Takayuki Sumiyoshi; Hiroshi Yokogawa

2011-12-14T23:59:59.000Z

228

Silica scaling in simulated geothermal brines  

DOE Green Energy (OSTI)

A 6.3 1/sec (100 GPM) titanium corrosion test loop was modified to provide a dynamic facility for studying the formation of silica deposits, their properties and fates, as a function of brine composition, temperature, and flow conditions. Scale formation was studied in a segmented heat exchanger operating under realistic conditions; the segmented design permitted examination of scale formations in five temperature regimes. The program was terminated after minimal exploratory operation because of reduced sponsor perceptions of the need for concern with scaling problems. The runs which were completed dealt cursorily with brine concentration and pH effects. Results are presented.

Bohlmann, E.G.; Shor, A.J.; Berlinski, P.; Mesmer, R.E.

1981-04-01T23:59:59.000Z

229

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

230

Silica-Coated Titania and Zirconia Colloids for Subsurface Transport  

E-Print Network (OSTI)

, Environmental Engineering Program, Yale University, New Haven, Connecticut 06520-8286, and Department of Civil transport experiments. Electrophoretic mobility measurements showed that coating with silica imparted electrophoretic mobility and size (by dynamic light scattering) over a 90-day period showed that the silica

Elimelech, Menachem

231

Functionalization of silica nanoparticles for polypropylene nanocomposite applications  

Science Conference Proceedings (OSTI)

Synthetic silica nanospheres of 20 and 100nm diameter were produced via the sol-gel method to be used as filler in polypropylene (PP) composites. Modification of the silica surface was further performed by reaction with organic chlorosilanes in order ...

Diego Bracho, Vivianne N. Dougnac, Humberto Palza, Raúl Quijada

2012-01-01T23:59:59.000Z

232

Community Geothermal Technology Program: Silica bronze project. Final report  

DOE Green Energy (OSTI)

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

233

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

234

PROPERTIES AND NANOSTRUCTURES OF NANO-MATERIALS PROCESSED BY SEVERE PLASTIC DEFORMATION (SPD).  

Science Conference Proceedings (OSTI)

Metallic materials usually exhibit higher strength but lower ductility after being plastically deformed by conventional techniques such as rolling, drawing and extrusion. In contrast, nanostructured metals and alloys processed by severe plastic deformation (SPD) have demonstrated both high strength and high ductility. This extraordinary mechanical behavior is attributed to the unique nanostructures generated by SPD processing. The combination of ultrafine grain size and high-density dislocations appears to enable deformation by new mechanisms not active in coarse-grained metals and alloys. These results demonstrate the possibility of tailoring the microstructures of metals and alloys by SPD to obtain superior mechanical properties. Nanostructured metals and alloys processed by SPD techniques have unique nanostructures not observed in nanomaterials synthesized by other techniques such as the consolidation of nanopowders. The SPD-generated nanostructures have many features related to deformation, including high dislocation densities, and high- and low-angle grain boundaries in equilibrium or nonequilibrium states. Future studies are needed to investigate the deformation mechanisms that relate the unique nanostructures with the superior mechanical properties exhibited by SPD-processed metals and alloys.

Zhu, Y. T. (Yuntian Theodore)

2001-01-01T23:59:59.000Z

235

Nanomaterials-Enhanced Electrically Switched Ion Exchange Process for Water Treatment  

Science Conference Proceedings (OSTI)

The objective of our work is to develop an electrically switched ion exchange (ESIX) system based on conducting polymer/carbon nanotube (CNT) nanocomposites as a new and cost-effective approach for removal of radioactive cesium, chromate, and perchlorate from contaminated groundwater. The ESIX technology combines ion exchange and electrochemistry to provide a selective, reversible method for the removal of target species from wastewater. In this technique, an electroactive ion exchange layer is deposited on a conducting substrate, and ion uptake and elution are controlled directly by modulation of the potential of the layer. ESIX offers the advantages of highly-efficient use of electrical energy combined with no secondary waste generation. Recently, we have improved upon the ESIX process by modifying the conducting substrate with carbon nanotubes prior to the deposition of the electroactive ion exchanger. The nanomaterial-based electroactive ion exchange technology will remove cesium-137, chromate, and perchlorate rapidly from wastewater. The high porosity and high surface area of the electroactive ion exchange nanocomposites results in high loading capacity and minimize interferences for non-target species. Since the ion adsorption/desorption is controlled electrically without generating a secondary waste, this electrically active ion exchange process is a green process technology that will greatly reduce operating costs.

Lin, Yuehe; Choi, Daiwon; Wang, Jun; Bontha, Jagannadha R.

2009-01-01T23:59:59.000Z

236

Laser Damage Precursors in Fused Silica  

Science Conference Proceedings (OSTI)

There is a longstanding, and largely unexplained, correlation between the laser damage susceptibility of optical components and both the surface quality of the optics, and the presence of near surface fractures in an optic. In the present work, a combination of acid leaching, acid etching, and confocal time resolved photoluminescence (CTP) microscopy has been used to study laser damage initiation at indentation sites. The combination of localized polishing and variations in indentation loads allows one to isolate and characterize the laser damage susceptibility of densified, plastically flowed and fractured fused silica. The present results suggest that: (1) laser damage initiation and growth are strongly correlated with fracture surfaces, while densified and plastically flowed material is relatively benign, and (2) fracture events result in the formation of an electronically defective rich surface layer which promotes energy transfer from the optical beam to the glass matrix.

Miller, P; Suratwala, T; Bude, J; Laurence, T A; Shen, N; Steele, W A; Feit, M; Menapace, J; Wong, L

2009-11-11T23:59:59.000Z

237

Water dynamics in controlled pore silica glasses  

DOE Green Energy (OSTI)

Water in porous silica glass is a suitable system for investigating the effect of confinement on translational diffusion. These systems are important because of their relevance in catalytic and separation processes. Two factors are to be considered in the case of confined water: (1) the effects of hydrophilic and hydrophobic surfaces on interfacial water and (2) how the dynamics of the hydrogen bond network changes due to the volume of confinement. Here quasi-elastic neutron scattering experiments at room temperature on water filled controlled pore glasses with radius of 15, 24 and 32 {angstrom}, are presented and analyzed using the random-jump diffusion model. Both the average residence time and the mean jump distance increase with decreasing pore radius.

Bordallo, H. N.; Herwig, K. W.; Dozier, W. D.; Drake, F.

1999-12-09T23:59:59.000Z

238

Ambient-pressure silica aerogel films  

SciTech Connect

Very highly porous (aerogel) silica films with refractive index in the range 1.006--1.05 (equivalent porosity 98.5--88%) were prepared by an ambient-pressure process. It was shown earlier using in situ ellipsometric imaging that the high porosity of these films was mainly attributable to the dilation or `springback` of the film during the final stage of drying. This finding was irrefutably reconfirmed by visually observing a `springback` of >500% using environmental scanning electron microscopy (ESEM). Ellipsometry and ESEM also established the near cent per cent reversibility of aerogel film deformation during solvent intake and drying. Film thickness profile measurements (near the drying line) for the aerogel, xerogel and pure solvent cases are presented from imaging ellipsometry. The thickness of these films (crack-free) were controlled in the range 0.1-3.5 {mu}m independent of refractive index.

Prakash, S.S. [New Mexico Univ., Albuquerque, NM (United States); Brinker, C.J. [New Mexico Univ., Albuquerque, NM (United States)]|[Sandia National Labs., Albuquerque, NM (United States); Hurd, A.J. [Sandia National Labs., Albuquerque, NM (United States)

1994-12-31T23:59:59.000Z

239

Numerical and Experimental Investigation of Inorganic Nanomaterials for Thermal Energy Storage (TES) and Concentrated Solar Power (CSP) Applications  

E-Print Network (OSTI)

The objective of this study is to synthesize nanomaterials by mixing molten salt (alkali nitrate salt eutectics) with inorganic nanoparticles. The thermo-physical properties of the synthesized nanomaterials were characterized experimentally. Experimental results allude to the existence of a distinct compressed phase even for the solid phase (i.e., in the nanocomposite samples). For example, the specific heat capacity of the nanocomposites was observed to be enhanced after melting and re-solidification - immediately after their synthesis; than those of the nanocomposites that were not subjected to melting and re-solidification. This shows that melting and re-solidification induced molecular reordering (i.e., formation of a compressed phase on the nanoparticle surface) even in the solid phase - leading to enhancement in the specific heat capacity. Numerical models (using analytical and computational approaches) were developed to simulate the fundamental transport mechanisms and the energy storage mechanisms responsible for the observed enhancements in the thermo-physical properties. In this study, a simple analytical model was proposed for predicting the specific heat capacity of nanoparticle suspensions in a solvent. The model explores the effect of the compressed phase – that is induced from the solvent molecules - at the interface with individual nanoparticles in the mixture. The results from the numerical simulations indicate that depending on the properties and morphology of the compressed phase – it can cause significant enhancement in the specific heat capacity of nanofluids and nanocomposites. The interfacial thermal resistance (also known as Kapitza resistance, or “Rk”) between a nanoparticle and the surrounding solvent molecules (for these molten salt based nanomaterials) is estimated using Molecular Dynamics (MD) simulations. This exercise is relevant for the design optimization of nanomaterials (nanoparticle size, shape, material, concentration, etc.). The design trade-off is between maximizing the thermal conductivity of the nanomaterial (which typically occurs for nanoparticle size varying between ~ 20-30nm) and maximizing the specific heat capacity (which typically occurs for nanoparticle size less than 5nm), while simultaneously minimizing the viscosity of the nanofluid. The specific heat capacity of nitrate salt-based nanomaterials was measured both for the nanocomposites (solid phase) and nanofluids (liquid phase). The neat salt sample was composed of a mixture of KNO3: NaNO3 (60:40 molar ratio). The enhancement of specific heat capacity of the nanomaterials obtained from the salt samples was found to be very sensitive to minor variations in the synthesis protocol. The measurements for the variation of the specific heat capacity with the mass concentration of nanoparticles were compared to the predictions from the analytical model. Materials characterization was performed using electron microscopy techniques (SEM and TEM). The rheological behavior of nanofluids can be non-Newtonian (e.g., shear thinning) even at very low mass concentrations of nanoparticles, while (in contrast) the pure undoped (neat) molten salt may be a Newtonian fluid. Such viscosity enhancements and change in rheological properties of nanofluids can be detrimental to the operational efficiencies for thermal management as well as energy storage applications (which can effectively lead to higher costs for energy conversion). Hence, the rheological behavior of the nanofluid samples was measured experimentally and compared to that of the neat solvent (pure molten salt eutectic). The viscosity measurements were performed for the nitrate based molten salt samples as a function of temperature, shear rate and the mass concentration of the nanoparticles. The experimental measurements for the rheological behavior were compared with analytical models proposed in the literature. The results from the analytical and computational investigations as well as the experimental measurements performed in this proposed study – were used to formul

Jung, Seunghwan

2012-05-01T23:59:59.000Z

240

Dendrimer Templated Synthesis of One Nanometer Rh and Pt Particles Supported on Mesoporous Silica: Catalytic Activity for Ethylene and Pyrrole Hydrogenation.  

E-Print Network (OSTI)

temperatures, data not shown). Butane was also observed as ainteractions. 47 Secondly, butane formation was reported to

Huang, Wenyu

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "mesoporous silica nanomaterials" from the National Library of EnergyBeta (NLEBeta).
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241

Phosphorylated mesoporous carbon as effective catalyst for the selective fructose dehydration to HMF  

SciTech Connect

Phosphorylated mesoporous carbons (PMCs) have been synthesized using an already reported one pot methodology. These materials have been applied as acidic catalysts in the dehydration of fructose to hydroxymethylfurfural (HMF). PMCs showed better selectivity to HMF compared to sulfonated carbon catalyst (SC) despite lower activity. The concentration of P-O groups correlates to the activity/selectivity of the catalysts; the higher the P-O concentration the higher the activity. However, the higher the P-O content the lower the selectivity to HMF. Indeed a lower concentration of the P-O groups (and even the acidic groups) minimized the degradation of HMF to levulinic acid and the formation of by-products, such as humines. Stability tests showed that these systems deactivate due to the formation of humines, water insoluble by-products derived from the dehydration of fructose, blocking the active site of the catalyst. Increasing the amount of P-O groups, higher amount of humines are formed; therefore carbons containing lower amount of phosphorylated groups, such as P/N-0.25, are less prone to deactivation. Keywords: Phosphorylated mesoporous carbons; fructose dehydration; HMF

Villa, Alberto [Universita di Milano, Italy; Schiavoni, Marco [University of Milan and INFN, Milano, Italy; Fulvio, Pasquale F [ORNL; Mahurin, Shannon Mark [ORNL; Dai, Sheng [ORNL; Mayes, Richard T [ORNL; Veith, Gabriel M [ORNL; Prati, Laura [Universita di Milano, Italy

2013-01-01T23:59:59.000Z

242

Tuning the Optical Properties of Mesoporous TiO2 Films by Nanoscale Engineering  

Science Conference Proceedings (OSTI)

Introducing mesoscale pores into spincoated titanium dioxide films, prepared by spincoating different sol-gel precursor solutions on silicon substrates and subsequent annealing at 350 C, 400 C or 450 C, respectively, affects several optical properties of the material. The change in refractive index observed for different mesoporous anatase films directly correlates with changes in pore size, but is also in a more complex manner influenced by the film thickness and the density of pores within the films. Additionally, the band gap of the films is blueshifted by the stress the introduction of pores exerts on the inorganic matrix. The differently sized pores were templated by Pluronic{reg_sign} block copolymers in the solgel solutions and tuned by employing different annealing temperatures for the film preparation. This study focused on elucidating the effect different templating materials (F127 and P123) have on the pore size of the final mesoporous titania film, and on understanding the relation of varying polymer concentration (taking P123 as an example) in the sol-gel solution to the pore concentration and size in the resultant titania film. Titania thin film samples or corresponding titanium dioxide powders were characterized by X-ray diffraction, nitrogen adsorption, ellipsometery, UV/Vis spectrometry and other techniques to understand the interplay between mesoporosity and optical properties.

Schwenzer, Birgit; Wang, Liang; Swensen, James S.; Padmaperuma, Asanga B.; Silverman, Gary; Korotkov, Roman; Gaspar, Daniel J.

2012-07-03T23:59:59.000Z

243

Synthesis of Monolithic Iron Incorporated Silica Aerogels by Ambient ...  

Science Conference Proceedings (OSTI)

With the Fe to Si molar ratio not exceeding 0.10, the bulk density of iron incorporated silica aerogels increased to 0.55g/cm3, while the porosity reduced to 76% ...

244

Biomolecular interactions and responses of human epithelial and macrophage cells to engineered nanomaterials.  

SciTech Connect

Engineered nanomaterials (ENMs) are increasingly being used in commercial products, particularly in the biomedical, cosmetic, and clothing industries. For example, pants and shirts are routinely manufactured with silver nanoparticles to render them 'wrinkle-free.' Despite the growing applications, the associated environmental health and safety (EHS) impacts are completely unknown. The significance of this problem became pervasive within the general public when Prince Charles authored an article in 2004 warning of the potential social, ethical, health, and environmental issues connected to nanotechnology. The EHS concerns, however, continued to receive relatively little consideration from federal agencies as compared with large investments in basic nanoscience R&D. The mounting literature regarding the toxicology of ENMs (e.g., the ability of inhaled nanoparticles to cross the blood-brain barrier; Kwon et al., 2008, J. Occup. Health 50, 1) has spurred a recent realization within the NNI and other federal agencies that the EHS impacts related to nanotechnology must be addressed now. In our study we proposed to address critical aspects of this problem by developing primary correlations between nanoparticle properties and their effects on cell health and toxicity. A critical challenge embodied within this problem arises from the ability to synthesize nanoparticles with a wide array of physical properties (e.g., size, shape, composition, surface chemistry, etc.), which in turn creates an immense, multidimensional problem in assessing toxicological effects. In this work we first investigated varying sizes of quantum dots (Qdots) and their ability to cross cell membranes based on their aspect ratio utilizing hyperspectral confocal fluorescence microscopy. We then studied toxicity of epithelial cell lines that were exposed to different sized gold and silver nanoparticles using advanced imaging techniques, biochemical analyses, and optical and mass spectrometry methods. Finally we evaluated a new assay to measure transglutaminase (TG) activity; a potential marker for cell toxicity.

Kotula, Paul Gabriel; Brozik, Susan Marie; Achyuthan, Komandoor E.; Greene, Adrienne Celeste; Timlin, Jerilyn Ann; Bachand, George David; Bachand, Marlene; Aaron, Jesse S.; Allen, Amy; Seagrave, Jean-Clare

2011-12-01T23:59:59.000Z

245

Silica Extraction at the Mammoth Lakes Geothermal Site  

DOE Green Energy (OSTI)

The purpose of this project is to develop a cost-effective method to extract marketable silica (SiO{sub 2}) from fluids at the Mammoth Lakes, California geothermal power plant. Marketable silica provides an additional revenue source for the geothermal power industry and therefore lowers the costs of geothermal power production. The use of this type of ''solution mining'' to extract resources from geothermal fluids eliminates the need for acquiring these resources through energy intensive and environmentally damaging mining technologies. We have demonstrated that both precipitated and colloidal silica can be produced from the geothermal fluids at Mammoth Lakes by first concentrating the silica to over 600 ppm using reverse osmosis (RO). The RO permeate can be used in evaporative cooling at the plant; the RO concentrate is used for silica and potentially other (Li, Cs, Rb) resource extraction. Preliminary results suggest that silica recovery at Mammoth Lakes could reduce the cost of geothermal electricity production by 1.0 cents/kWh.

Bourcier, W; Ralph, W; Johnson, M; Bruton, C; Gutierrez, P

2006-06-07T23:59:59.000Z

246

Silica gel sorption properties under adiabatic conditions  

DOE Green Energy (OSTI)

The SERI Sorption Test Facility was modified from isothermal operation to adiabatic operating conditions so that we could measure the adsorption/desorption characteristics of silica-gel-coated, parallel-channel geometry as a function of operating conditions and aspect ratio under adiabatic conditions. We performed single-blow experiments on two single-passage test cells with different aspect ratios, air flow rates, and inlet conditions. Both adsorption and desorption runs were performed. As the air flow rate and aspect ratio increase when other parameters are kept constant, the desiccant matrix loses its sorption capacity faster. The test cell operated near isothermal conditions rather than adiabatically because the cell walls had a large thermal mass compared with the amount of desiccant used. Since constructing single-passage test cells with small thermal masses that can be operated adiabatically at the Sorption Test Facility is difficult, further testing at this facility will be primarily for isothermal operation. The adiabatic experiments can best be done with multipassage test cells having small thermal masses relative to desiccant mass. A single-blow test facility for performing experiments with multipassage test cells was fabricated in FY 1984, and experiments were performed in an FY 1985 desiccant project.

Pesaran, A.A.; Choudhury, K.

1986-02-01T23:59:59.000Z

247

Silica recovery and control in Hawaiian geothermal fluids  

DOE Green Energy (OSTI)

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

248

Silica recovery and control in Hawaiian geothermal fluids. Final report  

DOE Green Energy (OSTI)

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

249

Molten Salt Nanomaterials for Thermal Energy Storage and Concentrated Solar Power Applications  

E-Print Network (OSTI)

The thermal efficiency of concentrated solar power (CSP) system depends on the maximum operating temperature of the system which is determined by the operating temperature of the TES device. Organic materials (such as synthetic oil, fatty acid, or paraffin wax) are typically used for TES. This limits the operating temperature of CSP units to below 400 degrees C. Increasing the operating temperature to 560 degrees C (i.e., the creeping temperature of stainless steel), can enhance the theoretical thermal efficiency from 54 percent to 63 percent. However, very few thermal storage materials are compatible for these high temperatures. Molten salts are thermally stable up to 600 degrees C and beyond. Using the molten salts as the TES materials confers several benefits, which include: (1) Higher operating temperature can significantly increase the overall cycle efficiency and resulting costs of power production. (2) Low cost of the molten salt materials can drastically reduce the cost. (3) The molten salts, which are environmentally safe, can also reduce the potential environmental impact. However, these materials suffer from poor thermo-physical properties. Impregnating these materials with nanoparticles can enhance these properties. Solvents doped with nanoparticles are termed as nanofluids. Nanofluids have been reported in the literature for the anomalous enhancement of their thermo-physical properties. In this study, the poor thermal properties of the molten salts were enhanced dramatically on mixing with nanoparticles. For example the specific heat capacity of these molten salt eutectics was found to be enhanced by as much as ~ 26 percent on mixing with nanoparticles at a mass fraction of ~ 1 percent. The resultant properties of these nanomaterials were found to be highly sensitive to small variations in the synthesis protocols. Computational models were also developed in this study to explore the fundamental transport mechanisms on the molecular scale for elucidating the anomalous enhancements in the thermo-physical properties that were measured in these experiments. This study is applicable for thermal energy storage systems utilized for other energy conversion technologies – such as geothermal energy, nuclear energy and a combination of energy generation technologies.

Shin, Donghyun

2011-08-01T23:59:59.000Z

250

Silica-polystyrene nanocomposite particles synthesized by nitroxide-mediated polymerization and their encapsulation through miniemulsion polymerization  

Science Conference Proceedings (OSTI)

Polystyrene (PS) chains with molecular weights comprised between 8000 and 64000 g?mol-1and narrow polydispersities were grown from the surface of silica nanoparticles (Aerosil A200 fumed silica and Stöber silica, resp.) through nitroxide-mediated ...

Bérangère Bailly; Anne-Carole Donnenwirth; Christèle Bartholome; Emmanuel Beyou; Elodie Bourgeat-Lami

2006-01-01T23:59:59.000Z

251

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.

252

Methods to quantify contamination effects on silica gel samples  

DOE Green Energy (OSTI)

This report describes a study to establish methods for measuring sorption degradation of contaminated solid desiccants and determining the identity and nature of the contaminants. A literature search was conducted to determine how contaminants affect the sorption properties of silica gel and advanced solid desiccant materials; the search yielded 73 papers. Silica gel was chosen for the contamination study; nine samples from various batches and suppliers were tested. Methods were established (1) to measure the degradation of desiccant adsorption capacity caused by regeneration processes and/or exposure to contaminants and (2) to determine the nature of these contaminants. Sorption measurements on a limited number of fresh silica gel samples showed that the water adsorption capacity varied about +-10%. The silica gel sample regenerated with electric heaters exhibited a maximum capacity degradation of 7%. Silica gel samples processed in other ways lost between 20% and 47% capacity, depending on the age and cycle of regeneration. The contaminants found were silicon, oxygen, carbon, and nitrogen using x-ray photoelectron spectroscopy. Contamination can degrade the water sorption capacity of desiccants.

Pesaran, A.A.; Thomas, T.M.; Penney, T.R.; Czanderna, A.W.

1986-09-01T23:59:59.000Z

253

Kinetics of silica deposition from simulated geothermal brines  

DOE Green Energy (OSTI)

Supersaturated brines were passed through columns packed with several forms of silica (crystalline ..cap alpha.. quartz, polycrystalline ..cap alpha.. quartz, and porous Vycor). Also, silica deposition on ThO/sub 2/ microspheres and titanium powder was studied under controlled conditions of supersaturation, pH, temperature, and salinity. The residence time was varied by adjustments of flow rate and column length. The silica contents of the input and effluent solutions were determined colorimetrically by a molybdate method which does not include polymers without special pretreatment. Essentially identical deposition behavior was observed once the substrate was thoroughly coated with amorphous silica and the BET surface area of the coated particles was taken into account. The reaction rate is not diffusion limited in the columns. The silica deposition is a function of the monomeric Si(OH)/sub 4/ concentration in the brine. The deposition on all surfaces examined was spontaneously nucleated. The dependence on the supersaturation concentration, hydroxide ion concentration, surface area, temperature and salinity were examined. Fluoride was shown to have no effect at pH 5.94 and low salinity. The empirical rate law which describes the data in 1 m NaCl in the pH range 5-7 and temperatures from 60 to 120/sup 0/C is given.

Bohlmann, E.G.; Mesmer, R.E.; Berlinski, P.

1980-03-01T23:59:59.000Z

254

FIRST LABORATORY OBSERVATION OF SILICA GRAINS FROM CORE COLLAPSE SUPERNOVAE  

SciTech Connect

We report the discovery of two supernova silica (SiO{sub 2}) grains in the primitive carbonaceous chondrites LaPaZ 031117 and Grove Mountains 021710. Only five presolar silica grains have been previously reported from laboratory measurements but they all exhibit enrichments in {sup 17}O relative to solar, indicating origins in the envelopes of asymptotic giant branch stars. The two SiO{sub 2} grains identified in this study are characterized by moderate enrichments in {sup 18}O relative to solar, indicating that they originated in Type II supernova ejecta. If compared to theoretical models, the oxygen isotopic compositions of these grains can be reproduced by mixing of different supernova zones. While both theoretical models of grain condensation and recent NASA Spitzer Space Telescope observations have suggested the presence of silica in supernova ejecta, no such grains had been identified, until now, in meteorites. The discovery of these two silica grains provides definitive evidence of the condensation of silica dust in supernova ejecta.

Haenecour, Pierre; Floss, Christine; Zinner, Ernst [Laboratory for Space Sciences, McDonnell Center for the Space Sciences and Physics Department, Washington University, One Brookings Drive, St. Louis, MO 63130-4899 (United States); Zhao Xuchao; Lin Yangting, E-mail: haenecour@wustl.edu [Key Laboratory of the Earth's Deep Interior, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029 (China)

2013-05-01T23:59:59.000Z

255

Optimization of mesoporous carbon structures for lithium–sulfur battery applications  

Science Conference Proceedings (OSTI)

Mesoporous carbon (MC) with tunable pore sizes (22nm, 12nm, 7nm, and 3nm) and pore volumes (from 1.3 to 4.8 cc/g) containing sulfur inside the pores were systematically studied as mesoporous carbon-sulfur (MCS) composite electrodes for Li-S batteries. Investigation on these MCS composites reveals that the pore structure has no influence on the battery performance at full sulfur loading conditions (the pore volume is fully filled by sulfur) but the maximum sulfur loading capability is higher for MC with larger pore volume. MC with large pore volumes, partial sulfur filling (part of the pore volume left unfilled), and surface modification, can have reasonably high sulfur loading, improved electrical and ionic contacts of sulfur with MC and with electrolytes, which subsequently promotes the battery performance. An initial capacity of ~1250 mAh/g (based on sulfur) and 650 mAh/g capacity retention over 100 cycles were obtained with 50 wt% sulfur loading in the MC with 22nm pore size (4.8 cc/g). When the surface of MCS was coated with Clevios P to reduce the dissolve of polysulfide anions in electrolytes, it exhibits a high initial discharge capacity of ~1390 mAh/g and improved cycling stability with capacity retention of ~840 mAh/g over 100 cycles. The reported correlation among the structure, sulfur filling, surface modification and the electrochemical performance of the MCS composite cathodes provides guidance in designing new electrodes for lithium-sulfur batteries

Li, Xiaolin; Cao, Yuliang; Qi, Wen N.; Saraf, Laxmikant V.; Xiao, Jie; Nie, Zimin; Mietek, Jaroniec; Zhang, Jiguang; Schwenzer, Birgit; Liu, Jun

2011-11-07T23:59:59.000Z

256

Dewetting of silica surfaces upon reactions with supercritical CO2 and brine: Pore-scale studies in micromodels  

E-Print Network (OSTI)

Influence of Compressed Carbon Dioxide on the Capillarity ofof supercritical carbon dioxide on silica. Langmuir 2001,Silica Surfaces and the Carbon Dioxide Molecule. J Phys Chem

Kim, Y.

2013-01-01T23:59:59.000Z

257

Silica membranes for hydrogen separation from coal gas. Final report  

DOE Green Energy (OSTI)

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

258

The dissociation of liquid silica at high pressure and temperature  

Science Conference Proceedings (OSTI)

Liquid silica at high pressure and temperature is shown to undergo significant structural modifications and profound changes in its electronic properties. Temperature measurements on shock waves in silica at 70-1000 GPa indicate that the specific heat of liquid SiO{sub 2} rises well above the Dulong-Petit limit, exhibiting a broad peak with temperature that is attributable to the growing structural disorder caused by bond-breaking in the melt. The simultaneous sharp rise in optical reflectivity of liquid SiO{sub 2} indicates that dissociation causes the electrical and therefore thermal conductivities of silica to attain metallic-like values of 1-5 x 10{sup 5} S/m and 24-600 W/m.K respectively.

Hicks, D; Boehly, T; Eggert, J; Miller, J; Celliers, P; Collins, G

2005-11-17T23:59:59.000Z

259

Electrospinning of silica nanofibers: characterization and application to biosensing  

E-Print Network (OSTI)

Electrospinning is a technique to achieve nanometer scale fibers. Similar to the conventional spin methods of making fabric, the viscous polymer solution is ejected from a spinneret; stretched and solidified in the air, the solution forms the fibers. The different part of electrospinning among others is that the fibers are driven by the electrostatic force, which induces the repulsion inside the liquid and further reduces the diameter. The resultant product is a non-woven membrane, which is porous; 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 and experimental time were studied. Materials used in the process are Polyvinylpyrrolidone (PVP), butanol and spin-on-glass coating solution, which act as polymer carrier, solvent, and silica-precursor, respectively. Polymer/silica precursor composite fibers were ejected from the needle of a plastic syringe when an electrical field, as high as several kV/cm, was applied. Then silica fibers were achieved by baking the composite ones at 773 oK for 12 h. Electrospun silica nanofibers were characterized as a function of polymer solution parameters. The calcined fibers were examined by using a field emission scanning electron microscope. The results showed that the fiber diameters decrease with decreasing proportion of polymer and silica precursor, and increase with a higher electric field. Pore sizes, defined as the grid areas enclosed by fibers on nearby layers, were also examined and showed no time-dependent tendency when the electrospin time was between 1-5 min. Fiber membranes were then used as the platform for protein detection. The results were compared with the control, which used glass slides as the platform. The results make it possible to make a more sensitive biosensing device.

Tsou, Pei-Hsiang

2006-08-01T23:59:59.000Z

260

Christopher Hartshorn  

Science Conference Proceedings (OSTI)

... HIV RT molecules. (Regional ACS conference 2010). Kumud R ... Mesoporous Silica Films. (Regional ACS conference 2002). HY Fan ...

2012-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "mesoporous silica nanomaterials" 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

Nanostructured Water Oxidation Catalysts - Energy Innovation ...  

Nanostructured Cobalt Oxide Clusters in Mesoporous Silica as Efficient Oxygen-Evolving Catalysts. Angewandte Chemie International Edition. Vol. 28: ...

262

Potential Health Effects of Crystalline Silica Exposures from Coal Fly Ash: A Literature Review  

Science Conference Proceedings (OSTI)

The amount of crystalline silica in coal fly ash (CFA) depends on a variety of factors, including the amount of silica in the pre-combustion coal, the combustion process, and emission control technologies among others. Occupational exposures to crystalline silica in CFA are related to these factors as well as activities associated with exposures and durations of exposure. This review summarizes the occupational and environmental health literature relevant to the presence of crystalline silica in CFA from...

2006-03-27T23:59:59.000Z

263

Analysis of the elastic behaviour of silica aerogels taken as a percolating system  

E-Print Network (OSTI)

289 Analysis of the elastic behaviour of silica aerogels taken as a percolating system T. Woignier of silica aerogels are performed using the three points flexural technique. The elastic behaviour is studied measurement - for silica aerogels. These highly porous materials are obtained from a sol-gel process. Solvent

Paris-Sud XI, Université de

264

Modular Hybrid Plasma Reactor for Low Cost Bulk Production of Nanomaterials  

SciTech Connect

INL developed a bench scale modular hybrid plasma system for gas phase nanomaterials synthesis. The system was being optimized for WO3 nanoparticles production and scale model projection to a 300 kW pilot system. During the course of technology development many modifications had been done to the system to resolve technical issues that had surfaced and also to improve the performance. All project tasks had been completed except 2 optimization subtasks. These 2 subtasks, a 4-hour and an 8-hour continuous powder production runs at 1 lb/hr powder feeding rate, were unable to complete due to technical issues developed with the reactor system. The 4-hour run had been attempted twice and both times the run was terminated prematurely. The modular electrode for the plasma system was significantly redesigned to address the technical issues. Fabrication of the redesigned modular electrodes and additional components had been completed at the end of the project life. However, not enough resource was available to perform tests to evaluate the performance of the new modifications. More development work would be needed to resolve these problems prior to scaling. The technology demonstrated a surprising capability of synthesizing a single phase of meta-stable delta-Al2O3 from pure alpha-phase large Al2O3 powder. The formation of delta-Al2O3 was surprising because this phase is meta-stable and only formed between 973-1073 K, and delta-Al2O3 is very difficult to synthesize as a single phase. Besides the specific temperature window to form this phase, this meta-stable phase may have been stabilized by nanoparticle size formed in a high temperature plasma process. This technology may possess the capability to produce unusual meta-stable nanophase materials that would be otherwise difficult to produce by conventional methods. A 300 kW INL modular hybrid plasma pilot scale model reactor had been projected using the experimental data from PPG Industries 300 kW hot wall plasma reactor. The projected size of the INL 300 kW pilot model reactor would be about 15% that of the PPG 300 kW hot wall plasma reactor. Including the safety net factor the projected INL pilot reactor size would be 25-30% of the PPG 300 kW hot wall plasma pilot reactor. Due to the modularity of the INL plasma reactor and the energy cascading effect from the upstream plasma to the downstream plasma the energy utilization is more efficient in material processing. It is envisioning that the material through put range for the INL pilot reactor would be comparable to the PPG 300 kW pilot reactor but the energy consumption would be lower. The INL hybrid plasma technology is rather close to being optimized for scaling to a pilot system. More near term development work is still needed to complete the process optimization before pilot scaling.

Peter C. Kong

2011-12-01T23:59:59.000Z

265

Capacity degradation of field-tested silica gel samples  

DOE Green Energy (OSTI)

Researchers at the Solar Energy Research Institute (SERI) have begun preliminary studies to quantify the effect of contamination of silica gel used in dehumidification processes of desiccant cooling systems. Sorption capacity degradation of field tested samples was measured, and the source of degradation was quantified using surface analysis experimental methods.

Penney, T.R.; Pesaran, A.A.; Thomas, T.M.

1985-06-01T23:59:59.000Z

266

Fractal Studies on Titanium-Silica Aerogels using SMARTer  

SciTech Connect

Power-law scattering approximation has been employed to reveal the fractal structures of solid-state titanium-silica aerogel samples. All small-angle neutron scattering (SANS) measurements were performed using 36 meters SANS BATAN spectrometer (SMARTer) at the neutron scattering laboratory (NSL) in Serpong, Indonesia. The mass fractal dimension of titanium-silica aerogels at low scattering vector q range increases from -1.4 to -1.92 with the decrease of acid concentrations during sol-gel process. These results are attributed to the titanium-silica aerogels that are growing to more polymeric and branched structures. At high scattering vector q range the Porod slope of -3.9 significantly down to -2.24 as the roughness of particle surfaces becomes higher. The cross over between these two regimes decreases from 0.4 to 0.16 nm{sup -1} with the increase of acid concentrations indicating also that the titanium-silica aerogels are growing.

Putra, E. Giri Rachman; Ikram, A.; Bharoto; Santoso, E. [Neutron Scattering Laboratory, BATAN, Kawasan Puspiptek Serpong, Tangerang 15314 (Indonesia); Fang, T. Chiar; Ibrahim, N. [Department of Physics, Faculty of Science Universiti Teknologi Malaysia (UTM), 81310 Skudai, Johor (Malaysia); Mohamed, A. Aziz [Materials Technology Group, Industrial Technology Division Agensi Nuklear Malaysia, 43000 Kajang (Malaysia)

2008-03-17T23:59:59.000Z

267

High temperature thermographic measurements of laser heated silica  

SciTech Connect

In situ spatial and temporal surface temperature profiles of CO{sub 2} laser-heated silica were obtained using a long wave infrared (LWIR) HgCdTe camera. Solutions to the linear diffusion equation with volumetric and surface heating are shown to describe the temperature evolution for a range of beam powers, over which the peak surface temperature scales linearly with power. These solutions were used with on-axis steady state and transient experimental temperatures to extract thermal diffusivity and conductivity for a variety of materials, including silica, spinel, sapphire, and lithium fluoride. Experimentally-derived thermal properties agreed well with reported values and, for silica, thermal conductivity and diffusivity are shown to be approximately independent of temperature between 300 and 2800K. While for silica our analysis based on a temperature independent thermal conductivity is shown to be accurate, for other materials studied this treatment yields effective thermal properties that represent reasonable approximations for laser heating. Implementation of a single-wavelength radiation measurement in the semi-transparent regime is generally discussed, and estimates of the apparent temperature deviation from the actual outer surface temperature are also presented. The experimental approach and the simple analysis presented yield surface temperature measurements that can be used to validate more complex physical models, help discriminate dominant heat transport mechanisms, and to predict temperature distribution and evolution during laser-based material processing.

Elhadj, S; Yang, S T; Matthews, M J; Cooke, D J; Bude, J D; Johnson, M; Feit, M; Draggoo, V; Bisson, S E

2009-11-02T23:59:59.000Z

268

Fabrication of magnetite/silica/titania core-shell nanoparticles  

Science Conference Proceedings (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

269

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

270

Scientific Evaluation of Nanomaterials of TiO{sub 2} and Related Derivatives in a Variety of Applications  

SciTech Connect

Altair Nanotechnolgies, Inc. (Altair) has performed and hereby reports on research and development of novel nanomaterials for applications in 1) advanced power storage devices, 2) sensors for chemical, biological and radiological agents and on an 3) investigation into mechanisms of living cell-nanoparticle interactions that will allow predictions of health and safety issues and potentially result in novel agents for remediation of chemical and biological hazards. The project was organized around four distinct objectives. Two of the objectives are focused on developments designed to dramatically improve the performance of rechargeable Li-Ion batteries. These efforts are based on extensions of Altair's proprietary TiO{sub 2} nanoparticles and nanoparticle aggregates in the form of lithium titanate spinel, lithium manganates and lithium cobaltates. A third objective leverages the core Altair nanomaterials technology to develop a unique (nanosensor) platform for the error-free, "lab on a chip" detection of chemical, biological and radiological agents for hazardous materials remediation and threat detection. The innovative approach taken by the Altair/Western Michigan team develops individual nanosensor elements built upon a construct that includes a target-specific receptor molecule coupled through a signal transducing nanomolecule to a gold, TiO{sub 2} or SiO{sub 2} nanoparticle coated with a high density of strongfluorescing molecules for signal amplification The final objective focuses on interaction mechanisms between cells and nanoparticles with the goal of understanding how specific chemical and physical properties of these nanoparticles influence that interaction. The effort will examine a range of microbes that have environmental or societal importance.

Spitler, Timothy M; Stewart, Matthew; Pasquier, Aurelien Du; Coleman, Michael; Gunasinghe, Thushara; Manev, Veselin; Stucky, Galen; Holden, Patricia; Neal, Andrea; Suh, Won Hyuk

2008-09-30T23:59:59.000Z

271

Flue gas injection control of silica in cooling towers.  

Science Conference Proceedings (OSTI)

Injection of CO{sub 2}-laden flue gas can decrease the potential for silica and calcite scale formation in cooling tower blowdown by lowering solution pH to decrease equilibrium calcite solubility and kinetic rates of silica polymerization. Flue gas injection might best inhibit scale formation in power plant cooling towers that use impaired makeup waters - for example, groundwaters that contain relatively high levels of calcium, alkalinity, and silica. Groundwaters brought to the surface for cooling will degas CO{sub 2} and increase their pH by 1-2 units, possibly precipitating calcite in the process. Recarbonation with flue gas can lower the pHs of these fluids back to roughly their initial pH. Flue gas carbonation probably cannot lower pHs to much below pH 6 because the pHs of impaired waters, once outgassed at the surface, are likely to be relatively alkaline. Silica polymerization to form scale occurs most rapidly at pH {approx} 8.3 at 25 C; polymerization is slower at higher and lower pH. pH 7 fluids containing {approx}220 ppm SiO{sub 2} require > 180 hours equilibration to begin forming scale whereas at pH 8.3 scale formation is complete within 36 hours. Flue gas injection that lowers pHs to {approx} 7 should allow substantially higher concentration factors. Periodic cycling to lower recoveries - hence lower silica concentrations - might be required though. Higher concentration factors enabled by flue gas injection should decrease concentrate volumes and disposal costs by roughly half.

Brady, Patrick Vane; Anderson, Howard L., Jr.; Altman, Susan Jeanne

2011-06-01T23:59:59.000Z

272

Mixed-Matric Membranes for CO2 and H2 Gas Separations Using Metal-Organic Framework and Mesoporus Hybrid Silicas  

Science Conference Proceedings (OSTI)

In this work, we have investigated the separation performance of polymer-based mixed-matrix membranes containing metal-organic frameworks and mesoporous hybrid silicas. The MOF/Matrimid{reg_sign} and MOP-18/Matrimid{reg_sign} membranes exhibited improved dispersion and mechanical strength that allowed high additive loadings with reduced aggregation, as is the case of the 80 wt% MOP-18/Matrimid{reg_sign} and the 80% (w/w) Cu-MOF/Matrimid{reg_sign} membranes. Membranes with up to 60% (w/w) ZIF-8 content exhibited similar mechanical strength and improved dispersion. The H{sub 2}/CO{sub 2} separation properties of MOF/Matrimid{reg_sign} mixed-matrix membranes was improved by either keeping the selectivity constant and increasing the permeability (MOF-5, Cu-MOF) or by improving both selectivity and permeability (ZIF-8). In the case of MOF-5/Matrimid{reg_sign} mixed-matrix membranes, the H{sub 2}/CO{sub 2} selectivity was kept at 2.6 and the H{sub 2} permeability increased from 24.4 to 53.8 Barrers. For the Cu-MOF/Matrimid{reg_sign} mixed-matrix membranes, the H{sub 2}/CO{sub 2} selectivity was kept at 2.05 and the H{sub 2} permeability increased from 17.1 to 158 Barrers. These two materials introduced porosity and uniform paths that enhanced the gas transport in the membranes. When ZIF-8/Matrimid{reg_sign} mixed-matrix membranes were studied, the H{sub 2}/CO{sub 2} selectivity increased from 2.9 to 4.4 and the permeability of H{sub 2} increased from 26.5 to 35.8 Barrers. The increased H{sub 2}/CO{sub 2} selectivity in ZIF-8/Matrimid{reg_sign} membranes was explained by the sieving effect introduced by the ZIF-8 crystals (pore window 0.34 nm) that restricted the transport of molecules larger than H{sub 2}. Materials with microporous and/or mesoporous cavities like carbon aerogel composites with zeolite A and zeolite Y, and membranes containing mesoporous ZSM-5 showed sieving effects for small molecules (e.g. H{sub 2} and CO{sub 2}), however, the membranes were most selective for CO{sub 2} due to the strong interaction of the zeolites with CO{sub 2}. For example, at 30 wt% ZSM-5 loading, the CO{sub 2}/CH{sub 4} selectivity increased from 34.7 (Matrimid{reg_sign}) to 56.4. The large increase in selectivity was the result of the increase in CO{sub 2} permeability from 7.3 (Matrimid{reg_sign}) to 14.6 Barrers. At 30 wt% ZSM-5 loading, the H{sub 2}/CH{sub 4} separation was also improved from 83.3 (Matrimid{reg_sign}) to 136.7 with an increase in H{sub 2} permeability from 17.5 (Matrimid{reg_sign}) to 35.3 Barrers. The 10% carbon aerogel-zeolite A and -zeolite Y composite/Matrimid{reg_sign} membranes exhibited an increase in the CO{sub 2}/CH{sub 4} separation from 34.7 to 71.5 (zeolite A composite) and to 57.4 (zeolite Y composite); in addition, the membrane exhibited an increase in the CO{sub 2}/N{sub 2} separation from 33.1 to 50 (zeolite A composite) and to 49.4 (zeolite Y composite), indicating that these type of materials have affinity for CO{sub 2}. The inclusion of mesoporosity enhanced the dispersion of the additive allowing loadings of up to 30% (w/w) without the formation of non-selective voids.

Inga Musselman; Kenneth Balkus, Jr.; John Ferraris

2009-01-07T23:59:59.000Z

273

Method for dissolution and stabilization of silica-rich fibers  

DOE Patents (OSTI)

This invention is comprised of a method for dissolving silica-rich fibers such as borosilicate fibers, fiberglass and asbestos to stabilize them for disposal. The method comprises (1) immersing the fibers in hot, five-weight-percent sodium hydroxide solution until the concentration of dissolved silica reaches equilibrium and a only a residue is left (about 48 hours), then immersing the residue in hot, five-weight-percent nitric acid until the residue dissolves (about 96 hours). After adjusting the pH of the dissolved fibers to be caustic, the solution can then be added to a waste vitrification stream for safe disposal. The method is useful in disposing contaminated HEME and HEPA filters.

Jantzen, C.M.

1992-12-31T23:59:59.000Z

274

Laser supported solid state absorption fronts in silica  

SciTech Connect

We develop a model based on simulation and experiment that explains the behavior of solid-state laser-supported absorption fronts generated in fused silica during high intensity (up to 5GW/cm{sup 2}) laser exposure. We find that the absorption front velocity is constant in time and is nearly linear in laser intensity. Further, this model can explain the dependence of laser damage site size on these parameters. This behavior is driven principally by the temperature-activated deep sub band-gap optical absorptivity, free electron transport and thermal diffusion in defect-free silica for temperatures up to 15,000K and pressures < 15GPa. The regime of parameter space critical to this problem spans and extends that measured by other means. It serves as a platform for understanding general laser-matter interactions in dielectrics under a variety of conditions.

Carr, C W; Bude, J D

2010-02-09T23:59:59.000Z

275

Method for dissolution and stabilization of silica-rich fibers  

DOE Patents (OSTI)

A method is described for dissolving silica-rich fibers such as borosilicate fibers, fiberglass and asbestos to stabilize them for disposal. The method comprises (1) immersing the fibers in hot, five-weight-percent sodium hydroxide solution until the concentration of dissolved silica reaches equilibrium and a only a residue is left (about 48 hours), then immersing the residue in hot, five-weight-percent nitric acid until the residue dissolves (about 96 hours). After adjusting the pH of the dissolved fibers to be caustic, the solution can then be added to a waste vitrification stream for safe disposal. The method is useful in disposing contaminated HEME and HEPA filters. 1 fig.

Jantzen, C.M.

1997-11-11T23:59:59.000Z

276

Molecular engineering of porous silica using aryl templates  

DOE Patents (OSTI)

A process is described for manipulating the porosity of silica using a series of organic template groups covalently incorporated into the silicate matrix. The templates in the bridged polysilsesquioxanes are selectively removed from the material by oxidation with oxygen plasma or other means, leaving engineered voids or pores. The size of these pores is dependent upon the length or size of the template or spacer. The size of the templates is measured in terms of Si-Si distances which range from about 0.67 nm to 1.08 nm. Changes introduced by the loss of the templates result in a narrow range of micropores (i.e. <2 nm). Both aryl and alkyl template groups are used as spacers. Novel microporous silica materials useful as molecular sieves, desiccants, and catalyst supports are produced. 3 figs.

Loy, D.A.; Shea, K.J.

1994-06-14T23:59:59.000Z

277

Molecular engineering of porous silica using aryl templates  

SciTech Connect

A process for manipulating the porosity of silica using a series of organic template groups covalently incorporated into the silicate matrix. The templates in the bridged polysilsesquioxanes are selectively removed from the material by oxidation with oxygen plasma or other means, leaving engineered voids or pores. The size of these pores is dependent upon the length or size of the template or spacer. The size of the templates is measured in terms of Si-Si distances which range from about 0.67 nm to 1.08 nm. Changes introduced by the loss of the templates result in a narrow range of micropores (i.e. <2 nm). Both aryl and alkyl template groups are used as spacers. Novel microporous silica materials useful as molecular seives, dessicants, and catalyst supports are produced.

Loy, Douglas A. (Albuquerque, NM); Shea, Kenneth J. (Irvine, CA)

1994-01-01T23:59:59.000Z

278

Silica aerogel: An intrinsically low dielectric constant material  

Science Conference Proceedings (OSTI)

Silica aerogels are highly porous solids having unique morphologies in wavelength of visible which both the pores and particles have sizes less than the wavelength of visible light. This fine nanostructure modifies the normal transport mechanisms within aerogels and endows them with a variety of exceptional physical properties. For example, aerogels have the lowest measured thermal conductivity and dielectric constant for any solid material. The intrinsically low dielectric properties of silica aerogels are the direct result of the extremely high achievable porosities, which are controllable over a range from 75% to more than 99.8 %, and which result in measured dielectric constants from 2.0 to less than 1.01. This paper discusses the synthesis of silica aerogels, processing them as thin films, and characterizing their dielectric properties. Existing data and other physical characteristics of bulk aerogels (e.g., thermal stablity, thermal expansion, moisture adsorption, modulus, dielectric strength, etc.), which are useful for evaluating them as potential dielectrics for microelectronics, are also given.

Hrubesh, L.W.

1995-04-01T23:59:59.000Z

279

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

280

Preparation of silica stabilized biological templates for the production of metal and layered nanoparticles  

Science Conference Proceedings (OSTI)

The present invention relates to a system and method providing for increased silica growth on a bio-template, wherein the bio-template is pretreated with aniline to produce a uniform silica attractive surface and yielding a significant silica layers of at least 10 nm, and more preferably at least 20 nm in thickness, thereby providing for a high degree of stability to the bio-template.

Culver, James N; Royston, Elizabeth; Brown, Adam; Harris, Michael

2013-02-26T23:59:59.000Z

Note: This page contains sample records for the topic "mesoporous silica nanomaterials" 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

CdSe quantum dots sensitized mesoporous TiO2 solar cells with CuSCN as solid-state electrolyte  

Science Conference Proceedings (OSTI)

Mesoporous TiO2 is functionalized by 3-mercaptopropyl trimethyoxysilane (MPTMS) to anchor CdSe quantum dots (QDs). The resulting TiO2/CdSe is combined with solid-state electrolyte (CuSCN) to form solar cells. It is found that the ...

Guanbi Chen; Lei Wang; Yu Zou; Xia Sheng; Hongjuan Liu; Xiaodong Pi; Deren Yang

2011-01-01T23:59:59.000Z

282

XAS of uranium(VI) sorbed onto silica, alumina, and montmorillonite  

Science Conference Proceedings (OSTI)

The purpose of this work is to determine the speciation (oxidation state and molecular structure) of uranium sorbed onto surfaces of silica

E. R. Sylwester; P. G. Allen; E. A. Hudson

2000-01-01T23:59:59.000Z

283

Synthesis and new structure shaping mechanism of silica particles formed at high pH  

SciTech Connect

For the sol-gel synthesis of silica particles under high pH catalytic conditions (pH>12) in water/ethanol solvent, we have deduced that the competing dynamics of chemical etching and sol-gel process can explain the types of silica particles formed and their morphologies. We have demonstrated that emulsion droplets that are generated by adding tetraethyl orthosilicate (TEOS) to a water-ethanol solution serve as soft templates for hollow spherical silica (1-2 {mu}m). And if the emulsion is converted by the sol-gel process, one finds that suspended solid silica spheres of diameter of {approx}900 nm are formed. Moreover, several other factors are found to play fundamental roles in determining the final morphologies of silica particles, such as by variation of the pH (in our case, using OH{sup -}) to a level where condensation dominates; by changing the volume ratios of water/ethanol; and using an emulsifier (specifically, CTAB) - Graphical abstract: 'Local chemical etching' and sol-gel process have been proposed to interpret the control of morphologies of silica particles through varying initial pHs in syntheses. Highlights: Black-Right-Pointing-Pointer Different initial pHs in our syntheses provides morphological control of silica particles. Black-Right-Pointing-Pointer 'Local chemical etching' and sol-gel process describes the formation of silica spheres. Black-Right-Pointing-Pointer The formation of emulsions generates hollow silica particles.

Zhang, Henan; Zhao, Yu [Department of Chemistry, The City College of The University of New York, 160 Convent Avenue, New York, NY 10031 (United States)] [Department of Chemistry, The City College of The University of New York, 160 Convent Avenue, New York, NY 10031 (United States); Akins, Daniel L., E-mail: akins@sci.ccny.cuny.edu [Department of Chemistry, The City College of The University of New York, 160 Convent Avenue, New York, NY 10031 (United States)

2012-10-15T23:59:59.000Z

284

Silica Exposure Assessment of Oil And Gas Drilling Workers During Hydraulic Fracking Process.  

E-Print Network (OSTI)

??The problem investigated in this study was that of identifying the silica exposure to the employees of an oil gas company during the fracking process… (more)

Li, Jigang

2011-01-01T23:59:59.000Z

285

Luminescent organosilicon polymers and sol-gel synthesis of nano-structured silica  

E-Print Network (OSTI)

sol-­?gel  synthesis  of  nano-­?structured  silica     by  a   Malvern  Zetasizer  Nano  series  instrument.  Zeta  of   aggregates   of   nano-­?C60.   Aquatic   Toxicol.  

Martinez, H. Paul

2011-01-01T23:59:59.000Z

286

Synthesis of Mesocellular Silica Foams with Tunable Window and Cell Dimensions  

E-Print Network (OSTI)

Polystyrene microspheres coated with cationic surfactants are easily prepared by micro- emulsion templates. These silica foams resemble dense aerogels. Introduction Because of their greatly enhanced pore

Yang, Peidong

287

Silicon Surface Texturing by Electro-Deoxidation of a Thin Silica ...  

Science Conference Proceedings (OSTI)

Presentation Title, Silicon Surface Texturing by Electro-Deoxidation of a Thin Silica Layer in Molten Salt. Author(s), Eimutis Juzeliunas, Antony Cox, Derek Fray

288

Cellular Effect of High Doses of Silica-Coated Quantum Dot ...  

Cellular Effect of High Doses of Silica-Coated Quantum Dot Profiled with High Throughput Gene Expression Analysis and High Content Cellomics ...

289

Thermal annealing of laser damage precursors on fused silica surfaces  

Science Conference Proceedings (OSTI)

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 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

290

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

291

Optical and radiographical characterization of silica aerogel for Cherenkov radiator  

E-Print Network (OSTI)

We present optical and X-ray radiographical characterization of silica aerogels with refractive index from 1.05 to 1.07 for a Cherenkov radiator. A novel pin-drying method enables us to produce highly transparent hydrophobic aerogels with high refractive index by shrinking wet-gels. In order to investigate the uniformity in the density (i.e., refractive index) of an individual aerogel monolith, we use the laser Fraunhofer method, an X-ray absorption technique, and Cherenkov imaging by a ring imaging Cherenkov detector in a beam test. We observed an increase in density at the edge of the aerogel tiles, produced by pin-drying.

Tabata, Makoto; Hatakeyama, Yoshikiyo; Kawai, Hideyuki; Morita, Takeshi; Nishikawa, Keiko

2012-01-01T23:59:59.000Z

292

Measurement of Radiation Damage on Silica Aerogel \\v Cerenkov Radiator  

E-Print Network (OSTI)

We measured the radiation damage on silica aerogel \\v Cerenkov radiators originally developed for the $B$-factory experiment at KEK. Refractive index of the aerogel samples ranged from 1.012 to 1.028. The samples were irradiated up to 9.8~MRad of equivalent dose. Measurements of transmittance and refractive index were carried out and these samples were found to be radiation hard. Deteriorations in transparency and changes of refractive index were observed to be less than 1.3\\% and 0.001 at 90\\% confidence level, respectively. Prospects of using aerogels under high-radiation environment are discussed.

S. K. Sahu et al

1996-04-11T23:59:59.000Z

293

Preparation of silica aerogels with improved mechanical properties and extremely low thermal conductivities through modified sol-gel process  

E-Print Network (OSTI)

Reported silica aerogels have a thermal conductivity as low as 15 mW/mK. The fragility of silica aerogels, however, makes them impractical for structural applications. The purpose of the study is to improve the ductility ...

Zuo, Yanjia

2010-01-01T23:59:59.000Z

294

Synthesis of silica nanoparticles by sol-gel: size-dependent properties, surface modification, and applications in silica-polymer nanocomposites — a review  

Science Conference Proceedings (OSTI)

Application of silica nanoparticles as fillers in the preparation of nanocomposite of polymers has drawnmuch attention, due to the increased demand for new materials with improved thermal, mechanical, physical, and chemical properties. Recent developments ...

Ismail Ab Rahman; Vejayakumaran Padavettan

2012-01-01T23:59:59.000Z

295

Electrochromic nanocomposite of silica/polyaniline prepared from a water-in-oil microemulsion solution  

Science Conference Proceedings (OSTI)

A composite nanoparticle of silica/polyaniline was synthesized from a microemulsion and it was tested as an electrochromic film. The compositions for the stable microemulsion system was selected as 65.4 wt% cyclohexane, 30.4 wt% surfactant and 4.2 wt% ... Keywords: electrochromic, inorganic-organic hybrid, nanoparticle, operation life time, polyaniline, silica

Taejin Hwang; Heung Yeol Lee; Hohyeong Kim; Gyuntak Kim

2010-11-01T23:59:59.000Z

296

Young's modulus evaluation by SAWs for porous silica low-k film with cesium doping  

Science Conference Proceedings (OSTI)

Young's moduli of porous silica low-k films with cesium (Cs) doping are determined by surface acoustic waves (SAWs) in this study. Four low-k samples doped with 0-30ppmwt% Cs in the precursor solution are investigated to check the mechanical promotion ... Keywords: Cesium doping, Low-k film, Porous silica, Surface acoustic waves, Young's modulus

X. Xiao; X. M. Shan; Y. Kayaba; K. Kohmura; H. Tanaka; T. Kikkawa

2011-05-01T23:59:59.000Z

297

Mechanism of silica precipitation by lowering pH in chemi-thermomechanical pulping black liquors  

Science Conference Proceedings (OSTI)

Black liquor is a complex colloidal system obtained by chemical pulping process. It comprises of lignin, nearly 50% of the total organic and Silica approx. 2-3% (OD basis) of the total inorganic components. Black liquor is fed to chemical recovery plant ... Keywords: black liquors, desilication and concentrators, lignin, silica

Muhammad Ikram Aujla; Ishtiaq-Ur-Rehman Ishtiaq-Ur-Rehman; Asad Javaid

2007-12-01T23:59:59.000Z

298

Nanotechnology for Solar-hydrogen Production via Photoelectrochemical Water-splitting: Design, Synthesis, Characterization, and Application of Nanomaterials and Quantum Dots  

E-Print Network (OSTI)

Hydrogen production by water-splitting using solar energy and nanostructure photocatalysts is very promising as a renewable, efficient, environmentally clean technology. The key is to reduce the cost of hydrogen production as well as increase the solar-to-hydrogen conversion efficiency by searching for cost-effective photocatalytic materials. In this dissertation, energy efficiency calculation was carried out based on hydrogen production observation to evaluate the nanomaterials activity. The results are important to gain better understanding of water-splitting reaction mechanism. Design, synthesis, characterization/properties and application of these nanomaterials was the road-map to achieve the research objectives. The design of TiO2 is selected based on unique photocatalytic and photovoltaic properties and high stability in aqueous solution. Various structures of nanocomposites TiO2 were designed according to their characteristics and potential activity. TiO2 with quantum dots, nanocomposites thin film, nanofibers, nanorods, nanowires (core/shell), nanotubes, nanopowders, nanoparticles, and nanosphere decorated with low cost metals, sensitized with dye, and doped with nitrogen are designed. Green physical and chemical synthesis methods such as sol-gel techniques, autoclave, microwave, electrospinning, wet impregnation, hydrothermal, chemical vapor deposition, template-based fabrication (porous anodic aluminium oxide membrane), drop casting, dip coating, wet coating were used to synthesize and fabricate the nanomaterials and quantum dots.Both bottom-up and top-down synthesis techniques were used. The ability to control and manipulate the size, shape/geometry, crystal structure, chemical compositions, interaction and interface properties of these materials at nano-scale during the synthesis enable to enhance their thermal, optical, chemical, electrical, …etc properties. Several characterization techniques such as XRD, XPS, EDS, SEM, UV-visible spectra, and optical microscopic and digital camera were also obtained to characterize the properties and confirm to achieve the desired design. The application or processing to test the activity of these nanomaterials for hydrogen production by water-splitting was conducted through extensive experimental program. It was carried out in a one photo-single column experimental set-up to detect hydrogen evolution. A high throughput screening process to evaluate single photo reduction catalysts was established here for simplicity, safety, cost-effective and flexibility of testing nanomaterials for water photoreduction reactivity and hydrogen generation. Therefore, methanol as electron donor or oxidation agent was mixed with water in equal volume ratio in order to prevent the oxygen evolution and only measured the time course of hydrogen production. The primary objectives of this study is to investigate the following (1) The structure-properties relationship through testing quantum dots, nanocomposites thin film, nanofibers, nanorods, nanowires (core/shell), nanotubes, nanopowders, nanoparticles, nanospheres of TiO2 decorated with metals, dye sensitization, and nitrogen-doping. (2) The role of adding electron donors/relays to solution and their effect on semiconductor surface-electrolyte interface under constant conditions such as KI, Mv 2, NaCl, NaHCO3, sea and pure water. (3) Band gap and defect engineering by cation and anion doping. (4) Quantum dots and dye sensitization effect. The nanomaterials activity evaluated based on observed hydrogen production rate (?mol/h/g) experimentally and based on the energy efficiency (percent) calculation. Major findings in this dissertation are (1) A high throughput screening process to evaluate single photoreduction catalysts for solar-hydrogen production by water-splitting was established. (2) nanofibers structure of TiO2 doped with

Alenzi, Naser D.

2010-12-01T23:59:59.000Z

299

Terahertz Time-Domain Spectroscopy Study of Silica Aerogels and Adsorbed Molecular Jiangquan Zhang and D. Grischkowsky*  

E-Print Network (OSTI)

Terahertz Time-Domain Spectroscopy Study of Silica Aerogels and Adsorbed Molecular Vapors Jiangquan time-domain spectroscopy (THz-TDS) study of hydrophobic and hydrophilic silica aerogels, and the adsorption of several molecular vapors in the hydrophilic silica aerogel. The hydrophobic and hydrophilic

Oklahoma State University

300

Encapsulated in silica: genome, proteome and physiology of the thermophilic bacterium Anoxybacillus flavithermus  

SciTech Connect

Gram-positive bacteria of the genus Anoxybacillus have been found in diverse thermophilic habitats, such as geothermal hot springs and manure, and in processed foods such as gelatin and milk powder. Anoxybacillus flavithermus is a facultatively anaerobic bacterium found in super-saturated silica solutions and in opaline silica sinter. The ability of A. flavithermus to grow in super-saturated silica solutions makes it an ideal subject to study the processes of sinter formation, which might be similar to the biomineralization processes that occurred at the dawn of life. We report here the complete genome sequence of A. flavithermus strain WK1, isolated from the waste water drain at the Wairakei geothermal power station in New Zealand. It consists of a single chromosome of 2,846,746 base pairs and is predicted to encode 2,863 proteins. In silico genome analysis identified several enzymes that could be involved in silica adaptation and biofilm formation, and their predicted functions were experimentally validated in vitro. Proteomic analysis confirmed the regulation of biofilm-related proteins and crucial enzymes for the synthesis of long-chain polyamines as constituents of silica nanospheres. Microbial fossils preserved in silica and silica sinters are excellent objects for studying ancient life, a new paleobiological frontier. An integrated analysis of the A. flavithermus genome and proteome provides the first glimpse of metabolic adaptation during silicification and sinter formation. Comparative genome analysis suggests an extensive gene loss in the Anoxybacillus/Geobacillus branch after its divergence from other bacilli.

Saw, Jimmy H [Los Alamos National Laboratory; Mountain, Bruce W [NEW ZEALAND; Feng, Lu [NANKAI UNIV; Omelchenko, Marina V [NCBI/NLM/NIH; Hou, Shaobin [UNIV OF HAWAII; Saito, Jennifer A [UNIV OF HAWAII; Stott, Matthew B [NEW ZEALAND; Li, Dan [NANKAI UNIV; Zhao, Guang [NANKAI UNIV; Wu, Junli [NANKAI UNIV; Galperin, Michael Y [NCBI/NLM/NIH; Koonin, Eugene V [NCBI/NLM/NIH; Makarova, Kira S [NCBI/NLM/NIH; Wolf, Yuri I [NCBI/NLM/NIH; Rigden, Daniel J [UNIV OF LIVERPOOL; Dunfield, Peter F [UNIV OF CALGARY; Wang, Lei [NANKAI UNIV; Alam, Maqsudul [UNIV OF HAWAII

2008-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "mesoporous silica nanomaterials" 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

Problems of Silica Scaling at Cerro Prieto Geothrmal Power Station  

DOE Green Energy (OSTI)

In the Cerro Prieto Geothermal field, where the predominant fluid in the reservoir is water, they have had problems with silica and other deposits in the first exploration wells as well as in production wells. Scaling problems have also been encountered in silencers, cyclone separators, drains, water pipes, etc. Some scale problems have also been encountered in the turbine blades of the geothermal electric plant. Most of these problems have been solved by corrective procedures which, in some cases, have turned into routine. Scale deposition is a problem that certainly diminishes the useful capacity of geothermal fluids with water predominance, but it does not actually endanger the installations, since this problem is under control.

Mercado, S.; Guiza, J.

1976-01-01T23:59:59.000Z

302

Hydrogen and oxygen adsorption stoichiometries on silica supported ruthenium nanoparticles  

DOE Green Energy (OSTI)

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

303

Performance predictions of silica-gel desiccant dehumidifiers  

DOE Green Energy (OSTI)

The analysis of a cross-cooled desiccant dehumidifier using silica gel in the form of sheets is described. This unit is the principal component of solar powered desiccant air conditioning system. The mathematical model has first been formulated describing the dynamics of the dehumidifier. The model leads to a system of nonlinear coupled heat and mass transfer equations for the sorption processes and linear heat transfer equations for the purging processes. The model accounts for the gas film resistance and for the moisture diffusion in the desiccant. The governing equations are solved by a finite difference scheme to obtain periodic steady state solutions. The accuracy of the theoretical predictions is ascertained by comparing them with the experimental results. The performance of the dehumidifier, for a chosen set of initial conditions and dehumidifier parameters, has also been given.

Mathiprakasam, B.; Lavan, Z.

1980-01-01T23:59:59.000Z

304

Preparation of silica or alumina pillared crystalline titanates  

Science Conference Proceedings (OSTI)

Layered crystalline titanates (CT) [Anthony and Dosch, US Patent 5 177 045 (1993)] are pillared with tetraethyl orthosilicate, 3-aminopropyltrimethoxysilane, and aluminum acetylacetonate to prepare porous and high surface area supports for sulfided NiMo catalyst. Tetra-ethyl orthosilicate or aluminum acetylacetonate intercalated CT are prepared by stepwise intercalation. First, the basal distance is increased by n-alkylammonium ions prior to intercalation with inorganic compounds. However, an aqueous solution of 3-aminopropyltrimethoxysilane could directly pillar CT without first swelling the titanate with n-alkylamine. The catalytic activities for hydrogenation of pyrene of sulfided NiMo supported silica or alumina pillared CT were higher than those of commercial catalysts (Shell324 and Amocat1C). The silicon and aluminum contents of the pillared CT, used as supports, have a considerable effect on the catalytic activities and physical properties of the supports.

Udomsak, S.; Nge, R.; Dufner, D.C.; Anthony, R.G. [Texas A and M Univ., College Station, TX (United States); Lott, S.E. [Sandia National Labs., Albuquerque, NM (United States)

1994-05-01T23:59:59.000Z

305

Mesoporous TiO{sub 2} aggregate photoanode with high specific surface area and strong light scattering for dye-sensitized solar cells  

Science Conference Proceedings (OSTI)

Phase-pure anatase TiO{sub 2} nanocrystallite aggregates synthesized by a continuous supercritical fluid process have been first used for fabricating mesoporous photoanodes of dye-sensitized solar cells (DSCs). Due to the small size (11 nm) of the TiO{sub 2} nanocrystallites in the aggregates, the mesoporous photoanode provides a high specific surface area, 80 m{sup 2}/g, which ensures high dye loading. At the same time, the submicrometer-sized aggregates endow the mesoporous photoanode with strong light scattering effect. Therefore, the light harvesting efficiency of the photoanode is increased. With an improved short-circuit current density, a high overall power conversion efficiency of 8.65% (100 mW/cm{sup 2}, AM 1.5) is achieved without additional scattering layers, 12% enhanced compared with the DSCs fabricated from commercial Degussa P25 with exactly the same procedures. In addition, this supercritical fluid process is scalable and rapid (less than one minute) for TiO{sub 2} aggregates synthesis, which will push the commercialization of DSCs in the future. - Graphical abstract: Due to the special morphology and structure, the photoanode of DSCs provides high specific surface area and strong light scattering at the same time, which results in high conversion efficiencies of the DSCs. Table of contents: Thanks to the synchronous realization of high specific surface area and strong light scattering, a high efficiency of 8.65% was achieved based on a novel mesoporous TiO{sub 2} aggregates photoanode for DSCs. Highlights: Black-Right-Pointing-Pointer The TiO{sub 2} aggregate photoanode provides a possible route for highly efficient DSCs. Black-Right-Pointing-Pointer Photoanode with high dye loading and light scattering is successfully fabricated. Black-Right-Pointing-Pointer TiO{sub 2} synthesized by a supercritical fluid process is first applied to DSCs. Black-Right-Pointing-Pointer The synthesis method and high efficiency will push the commercialization of DSCs.

Li, Chunhui; Luo, Yanhong; Guo, Xiaozhi; Li, Dongmei [Key Laboratory for Renewable Energy, Chinese Academy of Sciences, Beijing Key Laboratory for New Energy Materials and Devices, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)] [Key Laboratory for Renewable Energy, Chinese Academy of Sciences, Beijing Key Laboratory for New Energy Materials and Devices, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Mi, Jianli; So, Lasse; Hald, Peter [Center for Materials Crystallography, Department of Chemistry and Interdisciplinary Nanoscience Center, Aarhus University, DK-8000 Aarhus (Denmark)] [Center for Materials Crystallography, Department of Chemistry and Interdisciplinary Nanoscience Center, Aarhus University, DK-8000 Aarhus (Denmark); Meng, Qingbo, E-mail: qbmeng@iphy.ac.cn [Key Laboratory for Renewable Energy, Chinese Academy of Sciences, Beijing Key Laboratory for New Energy Materials and Devices, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)] [Key Laboratory for Renewable Energy, Chinese Academy of Sciences, Beijing Key Laboratory for New Energy Materials and Devices, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Iversen, Bo B., E-mail: bo@chem.au.dk [Center for Materials Crystallography, Department of Chemistry and Interdisciplinary Nanoscience Center, Aarhus University, DK-8000 Aarhus (Denmark)

2012-12-15T23:59:59.000Z

306

Determination of silica deposition rates and thresholds applied towards protection of injection reservoirs  

SciTech Connect

This program was instituted to quantify certain aspects of silica scaling deposition processes at the Miravalles Geothermal Field, Costa Rica. The program objective was to identify the highest temperature at which silica scale will develop from partially evaporated and significantly cooled geothermal liquid under operating conditions. Integral to the study objective was the quantification of certain aspects of silica deposition processes at the Miravalles Geothermal Field, Costa Rica. There, the objective was to reduce the scaling risk associated with adding a bottoming-cycle to generate more electricity from the liquids already being produced.

Geothermal Development Associates; Don Michels Associates

1999-07-01T23:59:59.000Z

307

Bioremediation of nanomaterials  

DOE Patents (OSTI)

The present invention provides a method comprising the use of microorganisms for nanotoxicity study and bioremediation. In some embodiment, the microorganisms are bacterial organisms such as Gram negative bacteria, which are used as model organisms to study the nanotoxicity of the fullerene compounds: E. coli W3110, a human related enterobacterium and Shewanella oneidensis MR-1, an environmentally important bacterium with versatile metabolism.

Chen, Frank Fanqing; Keasling, Jay D; Tang, Yinjie J

2013-05-14T23:59:59.000Z

308

Nanomaterials for Energy Technology  

Science Conference Proceedings (OSTI)

Mar 14, 2012 ... Catalytic Properties of AgCu Bimetallic Nanoparticles for PEMFC Cathode: ... Mansoo Choi2; Won Gi Kim2; Yang-Kook Sun2; Wonbong Choi1; ...

309

Rare Earth Based Nanomaterials  

Science Conference Proceedings (OSTI)

Efficient emission at such small size is provided by doping Ln3+-ions into a fluoride matrix. Therefore, NaGdF4:Er3+,Yb3+ nanoparticles are synthesized by ...

310

Session I: Nanomaterials  

Science Conference Proceedings (OSTI)

... transmission electron microscopy (TEM), and electron back scatter diffraction .... Such improvements were attributed to the availability of large numbers of ...

311

Synthesis of Nanomaterials I  

Science Conference Proceedings (OSTI)

Feb 16, 2010... Paul Millett1; Yu Wang2; 1Idaho National Laboratory; 2Michigan Tech ... forces experienced by particles segregated at fluid-fluid interfaces. ... to polymer pyrolysis under protective atmosphere and then integrity of ZnO ...

312

Mechanical Properties of Nanomaterials  

Science Conference Proceedings (OSTI)

Feb 18, 2010 ... Aerogels have lots of particular application especially as superinsulation materials because of their nano-size particles and porous distribution.

313

Low Dimensional Nanomaterials II  

Science Conference Proceedings (OSTI)

Oct 18, 2010... Current by Living Microorganisms: Ravi Saraf1; Chieu Nguyen1; Jennifer Kane 1; Jason Ong1; Devor O'Connor1; 1University of Nebraska

314

Nanomaterials for Energy Technologies  

Science Conference Proceedings (OSTI)

Mar 4, 2013 ... Energy materials having controlled nanoscale configurations offer a promise of much improved efficiency. In dye sensitized solar cells, ...

315

Nanomaterials for Information Technology  

Science Conference Proceedings (OSTI)

Mar 12, 2012... improved performance of numerous devices – sensors to solar cells ... strongly bonded to Cu current collectors, are anticipated to enhance ...

316

Low Dimensional Nanomaterials I  

Science Conference Proceedings (OSTI)

Oct 18, 2010 ... The Au-loaded SnO2 particles are heated between 500 and 700 °C in a ... solid foams under controlled sensor heating in microwave oven.

317

Three Dimensional Nanomaterials II  

Science Conference Proceedings (OSTI)

Oct 20, 2011... The University of Alabama; Pu-Xian Gao, University of Connecticut; .... kinetics that governs the mechanisms and morphology selection of ...

318

Method for making nanomaterials  

DOE Patents (OSTI)

A method of making a nanostructure by preparing a face centered cubic-ordered metal nanoparticle film from metal nanoparticles, such as gold and silver nanoparticles, exerting a hydrostatic pressure upon the film at pressures of several gigapascals, followed by applying a non-hydrostatic stress perpendicularly at a pressure greater than approximately 10 GPA to form an array of nanowires with individual nanowires having a relatively uniform length, average diameter and density.

Fan, Hongyou; Wu, Huimeng

2013-06-04T23:59:59.000Z

319

Multifunctional Carbon Nanomaterials  

Science Conference Proceedings (OSTI)

... Offices in Charleston (WV), Morgantown (WV) and Oak Ridge (TN) •Expertise in •Biomass fuels & products •Fossil fuels & products ...

320

Nanomaterials General II  

Science Conference Proceedings (OSTI)

Mar 6, 2013 ... Lithium-6 isotope has a significant thermal neutron cross-section and produces high energy charged particles on thermal neutron absorption.

Note: This page contains sample records for the topic "mesoporous silica nanomaterials" 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.


321

Two Dimensional Nanomaterials  

Science Conference Proceedings (OSTI)

Oct 19, 2011 ... The National Energy Technology Laboratory (NETL) is developing technologies for the next generation of higher-efficiency, lower emission ...

322

Carbon Nanomaterials and Heterostructures  

Science Conference Proceedings (OSTI)

Mar 12, 2012 ... This presentation aims to capture those recent research efforts in synthesis and applications of carbon nanotubes in Li-ion battery, bioelectronic ...

323

Stability of Nanomaterials  

Science Conference Proceedings (OSTI)

... that the increased Cu-Nb interface surface disrupts internal-stress relaxation ... and against Radiation: Xinghang Zhang1; Y. Chen1; D. Bufford1; K.Y. Yu1; .... the nanocrystalline range (exposures at temperatures in the range ...

324

Electrical Properties of Nanomaterials  

Science Conference Proceedings (OSTI)

Feb 15, 2010... Seong Jin Koh, University of Texas at Arlington; Navin Manjooran, ... in Porous Alumina Templates: Vijay Singh1; 1University of Kentucky

325

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.

Harrar, Jackson E. (Castro Valley, CA); Lorensen, Lyman E. (Orinda, CA); Locke, Frank E. (Lafayette, CA)

1982-01-01T23:59:59.000Z

326

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

327

Suitability of Silica Gel to Process INEEL Sodium Bearing Waste - Letter Report  

SciTech Connect

The suitability of using the silica gel process for Idaho National Engineering and Environmental Laboratory (INEEL) sodium bearing waste was investigated during fiscal year 2000. The study was co-funded by the Tanks Focus Area as part of TTP No. ID-77WT-31 and the High Level Waste Program. The task also included the investigation of possible other absorbents. Scoping tests and examination of past work showed that the silica gel absorption/adsorption and drying method was the most promising; thus only silica gel was studied and not other absorbents. The documentation on the Russian silica gel process provided much of the needed information but did not provide some of the processing detail so these facts had to be inferred or gleaned from the literature.

Kirkham, Robert John; Herbst, Alan Keith

2000-09-01T23:59:59.000Z

328

Synthesis of SiC ceramics by the carbothermal reduction of mineralized wood with silica  

DOE Green Energy (OSTI)

This paper describes the synthesis of SiC by the carbothermal reduction of mineralized wood with silica in acidic condition. The biomorphic cellular SiC ceramics were prepared by controlling the amount of silica and the size of SiC nanoparticles. Up to 20wt% of SiO2 was mineralized into wood cellular structures and the hierarchical structures such as cells, lumen, and pits were mainly retained after the thermal treatment at 1400 C.

Shin, Yongsoon; Wang, Chong M.; Exarhos, Gregory J.

2005-01-06T23:59:59.000Z

329

Assessment of Methods to Consolidate Iodine-Loaded Silver-Functionalized Silica Aerogel  

SciTech Connect

The U.S. Department of Energy is currently investigating alternative sorbents for the removal and immobilization of radioiodine from the gas streams in a nuclear fuel reprocessing plant. One of these new sorbents, Ag0-functionalized silica aerogels, shows great promise as a potential replacement for Ag-bearing mordenites because of its high selectivity and sorption capacity for iodine. Moreover, a feasible consolidation of iodine-loaded Ag0-functionalized silica aerogels to a durable SiO2-based waste form makes this aerogel an attractive choice for sequestering radioiodine. This report provides a preliminary assessment of the methods that can be used to consolidate iodine-loaded Ag0-functionalized silica aerogels into a final waste form. In particular, it focuses on experimental investigation of densification of as prepared Ag0-functionalized silica aerogels powders, with or without organic moiety and with or without sintering additive (colloidal silica), with three commercially available techniques: 1) hot uniaxial pressing (HUP), 2) hot isostatic pressing (HIP), and 3) spark plasma sintering (SPS). The densified products were evaluated with helium gas pycnometer for apparent density, with the Archimedes method for apparent density and open porosity, and with high-resolution scanning electron microscopy and energy dispersive spectroscopy (SEM-EDS) for the extent of densification and distribution of individual elements. The preliminary investigation of HUP, HIP, and SPS showed that these sintering methods can effectively consolidate powders of Ag0-functionalized silica aerogel into products of near-theoretical density. Also, removal of organic moiety and adding 5.6 mass% of colloidal silica to Ag0-functionalized silica aerogel powders before processing provided denser products. Furthermore, the ram travel data for SPS indicated that rapid consolidation of powders can be performed at temperatures below 950°C.

Matyas, Josef; Engler, Robert K.

2013-09-01T23:59:59.000Z

330

Dispersion Morphology of Poly(methyl acrylate)/Silica Nanocomposites  

SciTech Connect

Nearly monodisperse poly(methyl acrylate) (PMA) and spherical SiO{sub 2} nanoparticles (NP, d = 14 {+-} 4 nm) were co-cast from 2-butanone, a mutually good solvent and a displacer of adsorbed PMA from silica. The effects of NP content and post-casting sample history on the dispersion morphology were found by small-angle X-ray scattering supplemented by transmission electron microscopy. Analysis of the X-ray results show that cast and thermally annealed samples exhibited a nearly random particle dispersion. That the same samples, prior to annealing, were not well-dispersed is indicative of thermodynamic miscibility during thermal annealing over the range of NP loadings studied. A simple mean-field thermodynamic model suggests that miscibility results primarily from favorable polymer segment/NP surface interactions. The model also indicates, and experiments confirm, that subsequent exposure of the composites to the likely displacer ethyl acetate results in entropic destabilization and demixing into NP-rich and NP-lean phases.

D Janes; J Moll; S Harton; C Durning

2011-12-31T23:59:59.000Z

331

In-Situ Observation of Solid Electrolyte Interphase Formation in Ordered Mesoporous Hard Carbon by Small-Angle Neutron Scattering  

Science Conference Proceedings (OSTI)

The aim of this work was to better understand the electrochemical processes occurring during the cycling of a lithium-ion half-cell containing ordered mesoporous hard carbon using time-resolved in situ small-angle neutron scattering (SANS). Utilizing electrolytes containing mixtures of deuterated (2H) and non-deuterated (1H) carbonates, we have addressed the challenging task of monitoring the formation and evolution of the solid-electrolyte interphase (SEI) layer. An evolution occurs in the SEI layer during discharge from a composition dominated by a higher scattering length density (SLD) lithium salt, to a lower SLD lithium salt for the ethylene carbonate/dimethyl carbonate (EC/DMC) mixture employed. By comparing half-cells containing different solvent deuteration levels, we show that it is possible to observe both SEI formation and lithium intercalation occurring concurrently at the low voltage region in which lithium intercalates into the hard carbon. These results demonstrate that SANS can be employed to monitor complicated electrochemical processes occurring in rechargeable batteries, in a manner that simultaneously provides information on the composition and microstructure of the electrode.

Bridges, Craig A [ORNL; Paranthaman, Mariappan Parans [ORNL; Sun, Xiao-Guang [ORNL; Zhao, Jinkui [ORNL; Dai, Sheng [ORNL

2012-01-01T23:59:59.000Z

332

Silica precipitation and scaling in a dynamic loop system. [Design and testing of titanium corrosion test loop  

DOE Green Energy (OSTI)

A titanium corrosion test loop was modified to provide a dynamic facility for studying the formation of silica precipitates and scale from simulated geothermal brines as a function of composition, temperature, and flow conditions. A schematic of the modified loop system is presented. The principal components and connecting piping are all constructed of commercially pure titanium. These components include a centrifugal pump, silica saturator column, segmented heat exchanger, reheat heat exchanger, and a high pressure feed pump (stainless steel). The system is designed to circulate simulated geothermal brines saturated with silica to approximately 300/sup 0/C for study of silica scaling. Data obtained from a test run are included. (JGB)

Bohlmann, E.G.; Shor, A.J.; Berlinski, P.

1977-01-01T23:59:59.000Z

333

Solubility of Gases in Glass. II. He, Ne, and H2 in Fused Silica  

Science Conference Proceedings (OSTI)

The statistical thermodynamics of the gas?in?glass system provides a basic model of both physical and chemical solubility. The physical solubility result is essentially equivalent to that for monatomic solubility. The chemical solubility result is dependent upon the specific system involved. The model was compared with experiment for a variety of systems. Helium and neon in fused silica were examples of the physical solubility of monatomic gases. Variations of the thermal history of the fused silica did not appear to have a measurable effect on physical solubility as evidenced in the helium data. Hydrogen in fused silica was an example of the physical solubility of polyatomic gases. Physical solubility was measured by a modified Seiverts technique and was characterized by a linear dependence on pressure. Binding energies for the physically dissolved species were of the order expected for van der Waals bonding. Vibrational frequencies were on the order of 1013 sec?1 with the heavier species having the lower frequencies. Hydrogen in fused silica was also an example of the chemical solubility of polyatomic gases. The literature gave data for the chemical solution of hydrogen in fused silica

James F. Shackelford; Perry L. Studt; Richard M. Fulrath

1972-01-01T23:59:59.000Z

334

Synthesis of palladium-doped silica nanofibers by sol-gel reaction and electrospinning process  

Science Conference Proceedings (OSTI)

Nanofiber is drawing great attention nowadays with their high surface area per volume and flexibility in surface functionalities that make them favorable as a proton exchange membrane in fuel cell application. In this study, incorporation of palladium nanoparticles in silica nanofibers was prepared by combination of a tetraorthosilane (TEOS) sol-gel reaction with electrospinning process. This method can prevent the nanoparticles from aggregation by direct mixing of palladium nanoparticles in silica sol. The as-produced electrospun fibers were thermally treated to remove poly(vinyl pyrrolidone) (PVP) and condensation of silanol in silica framework. PVP is chosen as fiber shaping agent because of its insulting and capping properties for various metal nanoparticles. Scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and Fourier transform infrared spectroscopy (FTIR) were used to characterize the silica fibers and Pd nanoparticles on the fibers. Spun fibers with average diameter ranged from 100nm to 400nm were obtained at optimum operating condition and distribution of Pd nanoparticles on silica fibers was investigated.

San, Thiam Hui; Daud, Wan Ramli Wan; Kadhum, Abdul Amir Hassan; Mohamad, Abu Bakar; Kamarudin, Siti Kartom; Shyuan, Loh Kee; Majlan, Edy Herianto [Fuel Cell Institute, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor (Malaysia); Fuel Cell Institute, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia and Department of Chemical and Process Engineering, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor (Malaysia); Fuel Cell Institute, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor (Malaysia)

2012-06-29T23:59:59.000Z

335

Direct encapsulation of water-soluble drug into silica microcapsules for sustained release applications  

SciTech Connect

Direct encapsulation of water-soluble drug into silica microcapsules was facilely achieved by a sol-gel process of tetraethoxysilane (TEOS) in W/O emulsion with hydrochloric acid (HCl) aqueous solution containing Tween 80 and drug as well as cyclohexane solution containing Span 80. Two water-soluble drugs of gentamicin sulphate (GS) and salbutamol sulphate (SS) were chosen as model drugs. The characterization of drug encapsulated silica microcapsules by scanning electronic microscopy (SEM), FTIR, thermogravimetry (TG) and N{sub 2} adsorption-desorption analyses indicated that drug was successfully entrapped into silica microcapsules. The as-prepared silica microcapsules were uniform spherical particles with hollow structure, good dispersion and a size of 5-10 {mu}m, and had a specific surface area of about 306 m{sup 2}/g. UV-vis and thermogravimetry (TG) analyses were performed to determine the amount of drug encapsulated in the microcapsules. The BJH pore size distribution (PSD) of silica microcapsules before and after removing drug was examined. In vitro release behavior of drug in simulated body fluid (SBF) revealed that such system exhibited excellent sustained release properties.

Wang Jiexin; Wang Zhihui [Key Lab for Nanomaterials, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029 (China); Chen Jianfeng [Key Lab for Nanomaterials, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029 (China); Research Center of the Ministry of Education for High Gravity Engineering and Technology, Beijing University of Chemical Technology, Beijing 100029 (China)], E-mail: chenjf@mail.buct.edu.cn; Yun, Jimmy [Nanomaterials Technology Pte. Ltd., 28 Ayer Rajah Crescent 03-03, Singapore 139959 (Singapore)

2008-12-01T23:59:59.000Z

336

Solidification of Acidic, High Nitrate Nuclear Wastes by Grouting or Absorption on Silica Gel  

Science Conference Proceedings (OSTI)

The use of grout and silica gel were explored for the solidification of four types of acidic, high nitrate radioactive wastes. Two methods of grouting were tested: direct grouting and pre-neutralization. Two methods of absorption on silica gel were also tested: direct absorption and rotary spray drying. The waste simulant acidity varied between 1 N and 12 N. The waste simulant was neutralized by pre-blending calcium hydroxide with Portland cement and blast furnace slag powders prior to mixing with the simulant for grout solidification. Liquid sodium hydroxide was used to partially neutralize the simulant to a pH above 2 and then it was absorbed for silica gel solidification. Formulations for each of these methods are presented along with waste form characteristics and properties. Compositional variation maps for grout formulations are presented which help determine the optimum "recipe" for a particular waste stream. These maps provide a method to determine the proportions of waste, calcium hydroxide, Portland cement, and blast furnace slag that provide a waste form that meets the disposal acceptance criteria. The maps guide researchers in selecting areas to study and provide an operational envelop that produces acceptable waste forms. The grouts both solidify and stabilize the wastes, while absorption on silica gel produces a solid waste that will not pass standard leaching procedures (TCLP) if required. Silica gel wastes can be made to pass most leach tests if heated to 600ºC.

A. K. Herbst; S. V. Raman; R. J. Kirkham

2004-01-01T23:59:59.000Z

337

Nanostructured manganese oxide clusters supported on ...  

2 evolution at nano-structured Mn oxide clusters in mesoporous silica under very mild conditions for the ?rst time. For driving the catalyst with

338

Advanced Concepts for Hydrogen Storage  

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

Framework", Nature, 402, 276-279 (1999). Mesoporous Organosilica Material benzene-silica hybrid material Hydrogen storage behavior? S. Inagaki, S. Guan, T. Ohsuna, and...

339

Characterization of Dry-Air Aged Granules of Silver-Functionalized Silica Aerogel  

Science Conference Proceedings (OSTI)

This is a letter report to complete level 3 milestone "Assess aging characteristics of silica aerogels" for DOE FCRD program. Recently, samples of Ag0-functionalized silica aerogel were aged in flowing dry air for up to 6 months and then loaded with iodine. This dry-air aging simulated the impact of long-term exposure to process gases during process idling. The 6-month aged sample exhibited an iodine sorption capacity of 32 mass%, which was 9 mass % lower than that for an un-aged Ag0-functionalized silica aerogel. In an attempt to understand this decrease in sorption capacity, we characterized physical properties of the aged samples with Brunauer-Emmett-Teller (BET) nitrogen adsorption, X-ray diffraction (XRD), and high resolution scanning electron microscopy (SEM). The results showed no impact of aging on the aerogel microstructure or the silver nanoparticles in the aerogel, including their spatial distribution and morphology.

Matyas, Josef; Fryxell, Glen E.; Robinson, Matthew J.

2012-09-01T23:59:59.000Z

340

April 2013 Most Viewed Documents for Biology And Medicine | OSTI, US Dept  

Office of Scientific and Technical Information (OSTI)

April 2013 Most Viewed Documents for Biology And Medicine April 2013 Most Viewed Documents for Biology And Medicine Publications in biomedical and environmental sciences programs, 1981 Moody, J.B. (comp.) (1982) 306 Drug Retention Times Center for Human Reliability Studies (2007) 99 SURVEY OF NOISE SUPPRESSION SYSTEMS FOR ENGINE GENERATOR SETS. KRISHNA,C.R. (1999) 95 Defining the Effectiveness of UV Lamps Installed in Circulating Air Ductwork Douglas VanOsdell; Karin Foarde (2002) 84 Mesoporous Silica Nanomaterials for Applications in Catalysis, Sensing, Drug Delivery and Gene Transfection Daniela Rodica Radu (2005) 84 Advisory Committee on human radiation experiments. Supplemental Volume 2a, Sources and documentation appendices. Final report NONE (1995) 72 Dose and volume specification for reporting interstitial therapy

Note: This page contains sample records for the topic "mesoporous silica nanomaterials" 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

Most Viewed Documents - Biology and Medicine | OSTI, US Dept of Energy,  

Office of Scientific and Technical Information (OSTI)

Most Viewed Documents - Biology and Medicine Most Viewed Documents - Biology and Medicine Drug Retention Times Center for Human Reliability Studies (2007) External dose-rate conversion factors for calculation of dose to the public Not Available (1988) Carbon Dioxide Sequestering Using Microalgal Systems Daniel J. Stepan; Richard E. Shockey; Thomas A. Moe; et al. (2002) Mesoporous Silica Nanomaterials for Applications in Catalysis, Sensing, Drug Delivery and Gene Transfection Daniela Rodica Radu (2005) Tolerance doses for treatment planning Lyman, J.T. (1985) Preliminary Benchmarking Efforts and MCNP Simulation Results for Homeland Security Robert Hayes (2008) Function and dynamics of aptamers: A case study on the malachite green aptamer Wang, Tianjiao (2008) Extremophiles 2004 Frank Robb (2004) Elemental mercury removal using a wet scrubber.

342

April 2013 Most Viewed Documents for Chemistry | OSTI, US Dept of Energy,  

Office of Scientific and Technical Information (OSTI)

April 2013 Most Viewed Documents for Chemistry April 2013 Most Viewed Documents for Chemistry Lithium literature review: lithium's properties and interactions Jeppson, D.W.; Ballif, J.L.; Yuan, W.W.; Chou, B.E. (1978) 123 Electrical conductivity measurements of aqueous electrolyte solutions at high temperatures and high pressures Ho, P.C.; Palmer, D.A. (1995) 102 Vapor-liquid equilibria for nitric acid-water and plutonium nitrate-nitric acid-water solutions Maimoni, A. (1980) 95 Mesoporous Silica Nanomaterials for Applications in Catalysis, Sensing, Drug Delivery and Gene Transfection Daniela Rodica Radu (2005) 84 Flammability characteristics of combustible gases and vapors. [249 refs] Zabetakis, M.G. (1964) 80 Molecular catalytic hydrogenation of aromatic hydrocarbons and hydrotreating of coal liquids. Yang, Shiyong; Stock, L.M. (1996)

343

Very large-scale structures in sintered silica aerogels as evidenced by atomic force microscopy and ultra-small angle  

E-Print Network (OSTI)

Very large-scale structures in sintered silica aerogels as evidenced by atomic force microscopy of silica aerogels has been extensively studied mainly by scattering techniques (neutrons, X-rays, light) and atomic force microscopy (AFM) experiments have been carried out on aerogels at dierent steps of densi

Demouchy, Sylvie

344

Mercury Binding Sites in Thiol-Functionalized Mesostructured Silica  

SciTech Connect

Thiol-functionalized mesostructured silica with anhydrous compositions of (SiO{sub 2}){sub 1-x}(LSiO{sub 1.5}){sub x}, where L is a mercaptopropyl group and x is the fraction of functionalized framework silicon centers, are effective trapping agents for the removal of mercuric(II) ions from water. In the present work, we investigate the mercury-binding mechanism for representative thiol-functionalized mesostructures by atomic pair distribution function (PDF) analysis of synchrotron X-ray powder diffraction data and by Raman spectroscopy. The mesostructures with wormhole framework structures and compositions corresponding to x = 0.30 and 0.50 were prepared by direct assembly methods in the presence of a structure-directing amine porogen. PDF analyses of five mercury-loaded compositions with Hg/S ratios of 0.50-1.30 provided evidence for the bridging of thiolate sulfur atoms to two metal ion centers and the formation of chain structures on the pore surfaces. We find no evidence for Hg-O bonds and can rule out oxygen coordination of the mercury at greater than the 10% level. The relative intensities of the PDF peaks corresponding to Hg-S and Hg-Hg atomic pairs indicate that the mercury centers cluster on the functionalized surfaces by virtue of thiolate bridging, regardless of the overall mercury loading. However, the Raman results indicate that the complexation of mercury centers by thiolate depends on the mercury loading. At low mercury loadings (Hg/S {le} 0.5), the dominant species is an electrically neutral complex in which mercury most likely is tetrahedrally coordinated to bridging thiolate ligands, as in Hg(SBu{sup t}){sub 2}. At higher loadings (Hg/S 1.0-1.3), mercury complex cations predominate, as evidenced by the presence of charge-balancing anions (nitrate) on the surface. This cationic form of bound mercury is assigned a linear coordination to two bridging thiolate ligands.

Billinge, Simon J.L.; McKimmey, Emily J.; Shatnawi, Mouath; Kim, HyunJeong; Petkov, Valeri; Wermeille, Didier; Pinnavaia, Thomas J. (MSU); (CMU); (Iowa State)

2010-07-13T23:59:59.000Z

345

Permeability reduction of unconsolidated media due to stress-induced silica dissolution  

SciTech Connect

Permeability measurements were made on both glass beads and Ottowa sand under uniform confining stress conditions. Extreme permeability reduction (95%) of the glass beads was observed at temperatures exceeding 150/sup 0/C and confining pressures of 13.8 MPa with distilled water as the flowing fluid. Permeability reduction in the Ottowa sand (40%) was also observed at high temperature and confining pressure. Effluent analysis revealed high concentrations of silica. Subsequent 300 hour experiments with Ottowa sand exhibited a steady decrease in permeability with time. SEM photographs of post experiment cores, indicate that the permeability reduction is mainly due to stress induced silica dissolution at grain contacts.

Udell, K.S.; Lofy, J.D.

1985-03-01T23:59:59.000Z

346

Theoretical study of the light scattering from two alternating concentric double silica-gold nanoshell  

SciTech Connect

The cross section of two alternating concentric double silica-gold nanoshell (DSGNS) is obtained as a function of wavelength. Numerical calculations show that two alternating concentric DSGNSs display two separated scattering peaks that the intensity and position of the scattering peaks depend on two gold shells thicknesses and silica layer thickness between them. By varying thicknesses of the layers of the gold shells, two alternating concentric DSGNS can be designed with the scattering peak from the visible to infrared regions of the spectrum.

Khosravi, H. [Department of Physics, Kermanshah Azad University, Kermanshah, 67189-97551 (Iran, Islamic Republic of); Daneshfar, N. [Department of Physics, Razi University, Kermanshah, 67149-67346 (Iran, Islamic Republic of); Bahari, A. [Department of Physics, Lorestan University, Lorestan, 68137-17133 (Iran, Islamic Republic of)

2010-05-15T23:59:59.000Z

347

Internal Labeling Technique Tracks Nanoparticle Transport ...  

The nanomaterials can include metal or semi-metal oxide (e.g., silica), quantum dot, noble metal, magnetic metal oxide, organic polymer, metal salt, ...

348

Internal Labeling Technique Tracks Nanoparticle Transport  

The nanomaterials can include metal or semi-metal oxide (e.g., silica), quantum dot, noble metal, magnetic metal oxide, organic polymer, metal salt, ...

349

Lithium/V6O13 cells using silica nanoparticle-based composite electrolyte  

E-Print Network (OSTI)

Lithium/V6O13 cells using silica nanoparticle-based composite electrolyte Yangxing Li, Peter S) both in liquid electrolyte consisting of oligomeric poly(ethyleneglycol)dimethylether'/lithium bis of suppressing lithium dendrite growth due to the rigidity and immobility of the electrolyte structure

Khan, Saad A.

350

Inhibition of Lithium Dendrites by Fumed Silica-Based Composite Electrolytes  

E-Print Network (OSTI)

Inhibition of Lithium Dendrites by Fumed Silica-Based Composite Electrolytes Xiang-Wu Zhang State University, Raleigh, North Carolina 27695-7905, USA Lithium dendrite formation is investigated via in situ microscopy in a liquid electrolyte containing polyethylene glycol dimethyl ether lithium bis

Khan, Saad A.

351

Silica-alumina trihydrate filled epoxy castings resistant to arced SF.sub.6  

SciTech Connect

A cured, insulating, casting composition, having a coefficient of linear thermal expansion of below about 38 .times. 10.sup.-6 in./in./.degree. C and being resistant to arced sulfur hexafluoride gas, in contact with a metal surface in a sulfur hexafluoride gas environment, is made from hydantoin epoxy resin, anhydride curing agent and a filler combination of fused silica and alumina trihydrate.

Chenoweth, Terrence E. (Monroeville, PA); Yeoman, Frederick A. (Murrysville, PA)

1978-01-01T23:59:59.000Z

352

TESLA-FEL 2004-01 Silica Aerogel Radiators for Bunch Length  

E-Print Network (OSTI)

TESLA-FEL 2004-01 Silica Aerogel Radiators for Bunch Length Measurements J. B¨ahr a , V. Djordjadze aerogel are used to measure the electron bunch length at the photo injector test facility at DESY Zeuthen by the usage of aerogel is calculated analytically and Monte Carlo simulations are performed. It is shown

353

Silica control and materials tests at the Salton Sea geothermal field  

DOE Green Energy (OSTI)

The Lawrence Livermore Laboratory maintains and operates a test facility near Niland, California, in the Imperial Valley for field studies on SSGF brine chemistry, scale and solids control, materials, and injection. Recent work in silica control and materials testing is reviewed.

Quong, R.; Harrar, J.E.; McCright, R.D.; Locke, R.D.; Lorensen, L.E.; Tardiff, G.E.

1979-06-07T23:59:59.000Z

354

Coupling of Advanced Oxidation and Adsorption Processes onto Silica-Titania Composites for Low Level  

E-Print Network (OSTI)

was mercury adsorption onto calcium sulfate (CaSO4), a byproduct of the flue gas desulfurization (FGD) wet., Powers K.W., and Pitoniak E.R. (2004) Method for Purifying Flue Gases from Combustion Sources. PatentCoupling of Advanced Oxidation and Adsorption Processes onto Silica-Titania Composites for Low

Choate, Paul M.

355

Facile and sensitive epifluorescent silica nanoparticles for the rapid screening of EHEC  

Science Conference Proceedings (OSTI)

This study was to develop antibodies conjugated fluorescent dye-doped silica nanoparticles (FDS-NPs) aiming to increase signals for the rapid detection of Escherichia coli O157:H7 with glass slide method. The FDS-NPs were produced with microemulsion/solgel ...

Pravate Tuitemwong, Nut Songvorawit, Kooranee Tuitemwong

2013-01-01T23:59:59.000Z

356

Refractive index and density in F- and Cl-doped silica glasses  

Science Conference Proceedings (OSTI)

The refractive index and density of fluorine- and chlorine-doped silica glasses were measured as functions of fictive temperature. The halogen concentrations were observed to have a refractive index or density that is independent of the fictive temperature were found. This implies that these properties are not affected by any heat-treatment conditions.

Kakiuchida, Hiroshi; Shimodaira, Noriaki; Sekiya, Edson H.; Saito, Kazuya; Ikushima, Akira J. [Research Center for Advanced Photon Technology, Toyota Technological Institute, 2-12-1 Hisakata, Tempaku, Nagoya, Aichi 468-8511 (Japan); Research Center for Advanced Photon Technology, Toyota Technological Institute, 2-12-1 Hisakata, Tempaku, Nagoya, Aichi 468-8511, Japan and Research Center, Asahi Glass Co., Ltd., 1150 Hazawa-cho, Kanagawa, Yokohama, Kanagawa 221-8755 (Japan); Research Center for Advanced Photon Technology, Toyota Technological Institute, 2-12-1 Hisakata, Tempaku, Nagoya, Aichi 468-8511 (Japan)

2005-04-18T23:59:59.000Z

357

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; Pawel, Steven J [ORNL; Hunter, Scott Robert [ORNL; Haynes, James A [ORNL; Hillesheim, Daniel A [ORNL

2013-01-01T23:59:59.000Z

358

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

DOE Green Energy (OSTI)

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

1998-07-01T23:59:59.000Z

359

Determination of silica scale deposition rates and thresholds applied toward protection of injection reservoirs. Quarterly progress report, January 1, 1988--March 31, 1998  

DOE Green Energy (OSTI)

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 the deposited silica 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

1998-05-01T23:59:59.000Z

360

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

DOE Green Energy (OSTI)

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

Note: This page contains sample records for the topic "mesoporous silica nanomaterials" 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
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361

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

E-Print Network (OSTI)

IR luminescence and absorption in bismuth-doped silica glass-core fibers observed recently (see [arXiv:1106.2969v1 [physics.optics]) are argued to be caused by transitions in interstitial BiO molecules

Sokolov, V O; Dianov, E M

2011-01-01T23:59:59.000Z

362

Extreme Chromatography: Faster, Hotter, SmallerChapter 5 High-efficiency Liquid Chromatography Separations Achieved by Monolithic Silica Columns  

Science Conference Proceedings (OSTI)

Extreme Chromatography: Faster, Hotter, Smaller Chapter 5 High-efficiency Liquid Chromatography Separations Achieved by Monolithic Silica Columns Methods and Analyses eChapters Methods - Analyses Books AOCS Press Downloada

363

Smart Materials  

Science Conference Proceedings (OSTI)

Aug 5, 2010 ... A family of ordered mesoporous organic polymers and carbon solids are ... catalysis, bio- immobilization, water purification and electronic energy storage. ... Synthesis of Multi-Shelled Mesoporous Silica Hollow Nanospheres and ... silica hollow nanospheres (MMSHNs) with uniform size distribution (~150 ...

364

Study of a Threshold Cherenkov Counter Based on Silica Aerogels with Low Refractive Indices ?  

E-Print Network (OSTI)

To identify ? ± and K ± in the region of 1.0 ? 2.5 GeV/c, a threshold Cherenkov counter equipped with silica aerogels has been investigated. Silica aerogels with a low refractive index of 1.013 have been successfully produced using a new technique. By making use of these aerogels as radiators, we have constructed a Cherenkov counter and have checked its properties in a test beam. The obtained results have demonstrated that our aerogel was transparent enough to make up for loss of the Cherenkov photon yield due to a low refractive index. Various configurations for the photon collection system and some types of photomultipliers, such as the fine-mesh type, for a read out were also tested. From these studies, our design of a Cherenkov counter dedicated to ?/K separation up to a few GeV/c with an efficiency greater than 90 % was considered. 1

I. Adachi; T. Sumiyoshi; K. Hayashi; N. Iida; R. Enomoto; K. Tsukada; R. Suda; S. Matsumoto; K. Natori; M. Yokoyama; H. Yokogawa

1994-01-01T23:59:59.000Z

365

Flow cytometric analysis of respiratory tract cells exposed to oil shale and silica particulates. [Hamsters  

SciTech Connect

Flow cytometric techniques were used to measure the cytological and biochemical damage to respiratory tract cells in animals exposed to particulates. Hamsters were exposed to raw and spent oil shale particulates and silica by intratracheal instillation. Exfoliated lung cells were obtained by sacrificing the animals and lavaging the respiratory tract posterior to the trachea with saline. Cell samples were fixed in ethanol and stained with mithramycin for fluorescence analysis of DNA content. DNA content distributions from hamsters exposed to spent oil shale and silica particulates showed atypical changes 28 to 35 days later. Cell counts and total numbers of macrophages, leukocytes, and epithelial cells in the lavage fluid also showed marked changes related to time after exposure.

Steinkamp, J.A.; Wilson, J.S.

1979-01-01T23:59:59.000Z

366

Petrography study on altered flint aggregate by alkali-silica reaction  

SciTech Connect

The aim of our study is to improve our understanding of an alkali-silica reaction (ASR) via petrography. We used a chemical concrete subsystem: flint aggregate, portlandite and KOH. The altered flint aggregate is followed by optical microscopy and scanning electron microscopy (SEM) before and after acid treatment at different intervals. After acid treatment, the observations showed an increase in aggregate porosity and revealed internal degradation of the aggregate. This degradation created amorphous zones. Before acid treatment, the analyses on polished sections by scanning electron microscopy coupled with energy dispersive spectroscopy (EDS) enabled visualization of K{sup +} and Ca{sup 2+} penetration into the aggregate. The appearance of amorphous zones and penetration of positive ions into the aggregate are correlated with the increase in the molar fraction of silanol sites. This degradation is specific to the alkali-silica reaction.

Bulteel, D. [Departement Genie Civil de l'Ecole Nationale Superieure des Techniques Industrielles et des Mines de Douai, 941 rue Charles Bourseul, B.P. 838, F-59508, DOUAI Cedex (France)]. E-mail: bulteel@ensm-douai.fr; Rafai, N. [Laboratoire d'Etude et de Recherches des Materiaux a Arles, F-13631 ARLES (France); Degrugilliers, P. [Departement Genie Civil de l'Ecole Nationale Superieure des Techniques Industrielles et des Mines de Douai, 941 rue Charles Bourseul, B.P. 838, F-59508, DOUAI Cedex (France); Garcia-Diaz, E. [Departement Genie Civil de l'Ecole Nationale Superieure des Techniques Industrielles et des Mines de Douai, 941 rue Charles Bourseul, B.P. 838, F-59508, DOUAI Cedex (France)

2004-11-15T23:59:59.000Z

367

The Role of High Calcium Fly Ashes in Controlling Alkali-Silica Reactions in Concrete  

Science Conference Proceedings (OSTI)

The alkali-silica reaction (ASR) is a deleterious chemical reaction that can result in the deterioration of concrete structures. This report builds upon the results of a research and development study, funded by a broadly-based multi-national industry consortium, that is developing an engineering database on the long-term effectiveness of Class F fly ash and other supplementary cementing materials (SCMs) in counteracting ASR in concrete.

2002-11-20T23:59:59.000Z

368

A New Concept for the Fabrication of Hydrogen Selective Silica Membranes  

DOE Green Energy (OSTI)

We are attempting to fabricate H{sub 2}-selective silica-based films by ''layer-by-layer'' deposition as a new approach for thin films. A sonication-assisted deposition method was mainly used for ''layer-by-layer'' deposition. In addition, other approaches such as a dip-coating and the use of a polymer matrix with a layered silicate were contrived as well. This report shows the progress done during the 2nd Year of this award.

Michael Tsapatsis

2006-07-31T23:59:59.000Z

369

Modified Murnaghan equation of state applied to shock compression of silica, basalt, and dolomite  

DOE Green Energy (OSTI)

An equation of state previously used by the author is developed further and applied to geologic media. The equation is of the same form as the Murnaghan equation of state, but with the elastic constant terms replaced by the cohesive energy density (internal pressure), and the exponential term given as a sum of the Gruneisen parameter and the gaseous adiabatic exponent. Data for shock compression of silica, basalt, and dolomite are analyzed according to the equation.

Rogers, L.A.

1965-12-20T23:59:59.000Z

370

Sulfate Fining Chemistry in Oxidized and Reduced Soda-Lime-Silica Glasses  

SciTech Connect

Various reducing agents were used and their additions were varied to (1) increase glass quality through eliminating defects from silica scum, (2) decrease SOx emissions through changing the kind and quantity of reducing agents, and (3) improve production efficiency through increased flexibility of glass redox control during continuous processing. The work included measuring silica sand dissolution and sulfate decomposition in melts from glass batches. Glass batches were heated at a temperature-increase rate deemed similar to that experienced in the melting furnace. The sulfate decomposition kinetics was investigated with thermogravimetric analysis-differential thermal analysis and evolved gas analysis. Sulfur concentrations in glasses quenched at different temperatures were determined using X-ray fluorescence spectroscopy. The distribution of residual sand (that which was not dissolved during the initial batch reactions) in the glass was obtained as a function of temperature with optical microscopy in thin-sections of melts. The fraction of undissolved sand was measured with X-ray diffraction. The results of the present study helped Visteon Inc. reduce the energy consumption and establish the batch containing 0.118 mass% of graphite as the best candidate for Visteon glass production. The improved glass batch has a lower potential for silica scum formation and for brown fault occurrence in the final glass product. It was established that bubbles trapped in the melt even at 1450 C have a high probability to be refined when reaching the hot zone in the glass furnace. Furthermore, silica sand does not accumulate at the glass surface and dissolves faster in the batch with graphite than in the batch with carbocite.

Matyas, Josef; Hrma, Pavel R.

2005-05-13T23:59:59.000Z

371

In-depth survey report of silica flour dust during packing, transfer, and shipping at the Central Silica Company, Glass Rock Plant, Glass Rock, Ohio  

Science Conference Proceedings (OSTI)

A visit was made to the Central Silica Company, Glass Rock, Ohio to evaluate methods used to control employee exposure to silica dust. The control methods at this company included careful handling and transfer of damp materials, exhaust ventilation, good housekeeping procedures, and the use of respiratory protection. Evaluations were made of the packing area, transfer point, inside loading trucks, and ambient air at sections of the flour building. Control systems included a good exhaust-ventilation system and four ventilation hoods. Evaluations were made of samples collected by an MSA gravimeter dust sampler, the Del High volume electrostatic precipitation, and bulk and rafter samples. Dust control methods appeared to be effective due to the existence of good engineering controls, good work practices, and an effective respiratory protection program. Additional control measures included the handling of the ore as a damp material, thus reducing the generation of dust particles. Outside dust sources were being reduced. Most of the product was shipped in bulk. Plastic wrapping was used around pallet loads to reduce bag breakage and dust dispersion. A filtered air system controlled low dust levels in the Pebble Mill control room. Enclosed screens operated under negative pressure separated fine from coarse product at the process building.

Caplan, P.E.; Reed, L.D.; Amendola, A.A.; Cooper, T.C.

1981-12-01T23:59:59.000Z

372

Multiscale Filler Structure in Simplified Industrial Nanocomposite Silica/SBR Systems Studied by SAXS and TEM  

E-Print Network (OSTI)

Simplified silica (Zeosil 1165 MP) and SBR (140k carrying silanol end-groups) nanocomposites have been formulated by mixing of a reduced number of ingredients with respect to industrial applications. The thermo-mechanical history of the samples during the mixing process was monitored and adjusted to identical final temperatures. The filler structure on large scales up to micrometers was studied by transmission electron microscopy (TEM) and very small-angle X-ray scattering (SAXS). A complete quantitative model extending from the primary silica nanoparticle (of radius \\approx 10 nm), to nanoparticles aggregates, up to micrometer-sized branches with typical lateral dimension of 150 nm is proposed. Image analysis of the TEM-pictures yields the fraction of zones of pure polymer, which extend between the branches of a large-scale filler network. This network is compatible with a fractal of average dimension 2.4 as measured by scattering. On smaller length scales, inside the branches, small silica aggregates are present. Their average radius has been deduced from a Kratky analysis, and it ranges between 35 and 40 nm for all silica fractions investigated here (\\phi_si = 8-21% vol.). A central piece of our analysis is the description of the interaggregate interaction by a simulated structure factor for polydisperse spheres representing aggregates. A polydispersity of 30% in aggregate size is assumed, and interactions between these aggregates are described with a hard core repulsive potential. The same distribution in size is used to evaluate the polydisperse form factor. Comparison with the experimental intensity leads to the determination of the average aggregate compacity (assumed identical for all aggregates in the distribution, between 31% and 38% depending on \\phi_si), and thus aggregation number (ca. 45, with a large spread). Because of the effect of aggregate compacity and of pure polymer zones, the volume fraction of aggregates is higher in the branches than \\phi_si. The repulsion between aggregates has a strong effect on the apparent isothermal compressibility: it leads to a characteristic low-q depression, which cannot be interpreted as aggregate mass decrease in our data. In addition, the reinforcement effect of these silica structures in the SBR-matrix is characterized with oscillatory shear and described with a model based on the same aggregate compacity. Finally, our results show that it is possible to analyze the complex structure of interacting aggregates in nanocomposites of industrial origin in a self-consistent and quantitative manner.

Guilhem Baeza; ANNE-CAROLINE GENIX; Christophe Degrandcourt; Laurent Petitjean; Jérémie Gummel; Marc Couty; Julian OBERDISSE

2012-12-20T23:59:59.000Z

373

Quartz dissolution and silica deposition in hot-dry-rock geothermal systems  

DOE Green Energy (OSTI)

The kinetics of quartz dissolution control the produced fluid dissolved silica concentration in geothermal systems in which the downhole residence time is finite. The produced fluid of the Phase I, Run Segment 5 experimental Hot Dry Rock (HDR) geothermal system at Fenton Hill, NM, was undersaturated with respect to quartz in one pass through the reservoir, suggesting that the rate of granite dissolution governed the outlet dissolved silica concentration in this system. The literature data for the rate of quartz dissolution in water from 65 to 625/sup 0/C is correlated using an empirical rate law which is first order in quartz surface area and degree of undersaturation of the fluid. The Arrhenius plot (ln k vs T/sup -1/) is linear over eight orders of magnitude of the rate constant, verifying the validity of the proposed rate expression. Carefully performed quartz dissolution experiments in the present study duplicated the literature data and completed the data base in the temperature range from 150 to 250/sup 0/C. Identical experiments using crushed granite indicate that the rate of quartz dissolution in the presence of granite could be as much as 1 to 2 orders of magnitude faster than the rates observed in the pure quartz experiments. A temperature dependent HDR reservoir model incorporates the quartz dissolution rate law to simulate the dissolved silica behavior during the Fenton Hill Run Segment 5 experiment. For this low-permeability, fracture-dominated reservoir, the assumptions of one-dimensional plug flow through a vertically-inclined rectangular fracture and one-dimensional rock heat conduction perpendicular to the direction of flow are employed. These simplifications lead to an analytical solution for the temperature field in the reservoir.

Robinson, B.A.

1982-07-01T23:59:59.000Z

374

BNL Center for Functional Nanomaterials  

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

631-344-3093 Email: msfeir@bnl.gov Matthew Sfeir Matthew Sfeir Electronic Materials: Ultrafast and Optical Spectroscopy Matt Sfeir is a staff scientist in the Electronic Materials...

375

BNL Center for Functional Nanomaterials  

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

for Postdoctoral Researchers. Her research at the CFN focuses on the combination of ultrafast laser excitation with Low Temperature Scanning Tunneling Microscopy (LT-STM)...

376

BNL Center for Functional Nanomaterials  

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

of nanoparticles from noble metals and semiconductors, nanoparticles surface modification an DNA-driven nanoparticle self-assembly. She uses small angle X-ray scattering...

377

Thermodynamics and Processing of Nanomaterials  

Science Conference Proceedings (OSTI)

Register as a New User ... Symposium, Surfaces and Heterostructures at Nano- or Micro-Scale and Their ... Data Transmission Performance of Graphene Interconnects · Development and Mechanical Characterization of Novel Alumina Based ... at a Polymer Surface Monitored by Localized Surface Plasmon Resonance.

378

BNL | CFN: Soft & Biological Nanomaterials  

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

that are now became available. Approaches based on self-assembly of systems from nano-components might offer tremendous cost advantages and almost a magical ease of...

379

Nanomaterials Environmental Health and Safety  

Science Conference Proceedings (OSTI)

... Year after year, global spending on nanotechnology research and development (R&D) has ratcheted upward—to more than $13 billion in 2008. ...

2010-11-05T23:59:59.000Z

380

BNL Center for Functional Nanomaterials  

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

ma900682u) Greene, A.; Grubbs, R. B. Current Methods for N-Alkoxyamine Synthesis. ACS Symposia 2009, 1024 (ControlledLiving Radical Polymerization: Progress in RAFT, DT,...

Note: This page contains sample records for the topic "mesoporous silica nanomaterials" 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

Special Topics: Nanomaterials: Web resources  

Science Conference Proceedings (OSTI)

WEB: Material Innovations: from Nanotech to Biotech and Beyond! Presentations from the 2007 ACS Presidential Session, 0, 759, Todd Osman, 1/9/2008 7:45 ...

382

BNL Center for Functional Nanomaterials  

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

Z Xu, M Cotlet, H Wang, Synthesis and characterization of ethylene glycol substituted PPV derivatives, ACS Applied Materials and Interfaces, 2: ASAP (2010) Links: personal webpage...

383

BNL Center for Functional Nanomaterials  

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

Fax: 631-344-3093 Email: pzahl@bnl.gov Percy Zahl Percy Zahl Interface Sciences Catalysis Percy Zahl is an Associate Scientist in the Proximal Probe Microscopy facility of...

384

BNL Center for Functional Nanomaterials  

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

916 Fax: 631-344-3093 Email: stenney@bnl.gov Samuel Tenney Interface Science Catalysis Samuel Tenney is a postdoctoral research associate in the Interface Science and Catalysis...

385

BNL Center for Functional Nanomaterials  

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

631-344-3093 Email: psutter@bnl.gov Peter Sutter Peter Sutter Interface Sciences Catalysis Peter Sutter leads the Interface Science and Catalysis Group in the Center for...

386

BNL Center for Functional Nanomaterials  

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

344-3093 Email: sadowski@bnl.gov Jurek Sadowski Jurek Sadowski Interface Sciences Catalysis Jerzy (Jurek) Sadowski is an Associate Scientist in the Proximal Probe Microscopy...

387

March 2008 JOM: Producing Nanomaterials  

Science Conference Proceedings (OSTI)

"Laboratory Workplace Safety Practices and Sampling and Analysis ... “Insurers would be prudent to consider adverse scenarios (to human health) when ...

388

BNL Center for Functional Nanomaterials  

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

one-dimensional nanostructures: M. C. Strus, L. Zalamea, A. Raman, R. B. Pipes, C. V. Nguyen, and E. A. Stach, Nano Lett., 8 (2), 544 -550, 2008. Electrical properties of ZnO...

389

BNL Center for Functional Nanomaterials  

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

energy: The role of the third- and higher-order contributions, Deyu Lu, Huy-Viet Nguyen, Giulia Galli, J. Chem. Phys., 133: 154110, 2010. Van der Waals interactions in...

390

BNL Center for Functional Nanomaterials  

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

program. He obtained both his B.S. and Ph.D. from the University of Washington in Seattle. Following post-doctoral work at the Fritz Haber Institute in Berlin and at Lawrence...

391

BNL Center for Functional Nanomaterials  

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

2007). In the study of his M. Phil. Degree, he synthesized bulk high-Tc cuprate superconductors (doped YBCO and BSCCO) by employing solid-state reaction methods and...

392

BNL Center for Functional Nanomaterials  

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

single-electron tunneling devices, superconductivity in metal nanoparticles, nanocrystal-based electronic devices, and ferroelectric non-volatile memories. He earned the...

393

2012 Functional and Structural Nanomaterials  

Science Conference Proceedings (OSTI)

3D Multiwall Carbon Nanotubes (MWCNTs) for Li-Ion Battery Anode ... Applications of TiO2 Nanotubular Arrays by Atomic Layer Deposition and Nanotemplating.

394

Nanomaterials: Nomenclature, Novelty, and Necessity  

Science Conference Proceedings (OSTI)

ADVERTISING INFORMATION .... carbon nanocrystal aggregates present in the atmosphere were analyzed via .... Nanoceramic powders, the most commercially important of which are simple metal oxides, constitute almost 90% of the total market. ... It is anticipated that there will be significant impact in the energy area, ...

395

Microfluidic synthesis of colloidal nanomaterials  

E-Print Network (OSTI)

This thesis focuses on microfluidics based approaches for synthesis and surface-engineering of colloidal particles. Bottom-up assembly through colloidal nucleation and growth is a popular route to the controlled synthesis ...

Khan, Saif A

2006-01-01T23:59:59.000Z

396

BNL Center for Functional Nanomaterials  

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

fcamino@bnl.gov Fernando Camino Fernando Camino Electronic Materials: Nanofabrication, Thin Film Materials and Devices Fernando Camino works in the Electronic Materials group of...

397

Mechanomutable Nanomaterials: Multiscale Computational and ...  

Science Conference Proceedings (OSTI)

Abstract Scope, Mutable materials are found widely in biology, characterized by a material's capacity to change its properties under external cues based on ...

398

BNL Center for Functional Nanomaterials  

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

and G. W. Flynn, "High-resolution scanning tunneling microscopy imaging of mesoscopic graphene sheets on an insulating surface," Proceedings of the National Academy of Sciences of...

399

BNL Center for Functional Nanomaterials  

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

expertise of his covers semiconductor nanowire devices, organichybrid photovoltaics, nanomicrofabrication, and electronic transport & optoelectronic measurements. He received...

400

Atomic structure of Au-nanoparticles on silica support by X-ray PDF study  

SciTech Connect

We investigated the atomic structure of gold nanoparticles with an average size of 5 nm in diameter, supported by silica. We used high-energy X-ray diffraction and the atomic pair distribution function (PDF) to probe the local atomic structure. Measurements were performed from 25 to 950 C. The structure is approximately fcc in average but exhibits small distortions. The structural distortion increases with the temperature and could be related to the catalytic activity of gold nanoparticles. Above 425 C, rapid particle growth and coalescence were observed.

Dmowski, W. [University of Tennessee, Knoxville (UTK); Yin, Hongfeng [ORNL; Dai, Sheng [ORNL; Overbury, Steven {Steve} H [ORNL; Egami, T. [University of Tennessee, Knoxville (UTK)

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "mesoporous silica nanomaterials" 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

Atomic Structure of Au Nanoparticles on a Silica Support by an X-ray PDF Study  

SciTech Connect

We investigated the atomic structure of gold nanoparticles with an average size of {approx}5 nm in diameter, supported by silica. We used high-energy X-ray diffraction and the atomic pair distribution function (PDF) to probe the local atomic structure. Measurements were performed from 25 to 950 C. The structure is approximately fcc in average but exhibits small distortions. The structural distortion increases with the temperature and could be related to the catalytic activity of gold nanoparticles. Above 425 C, rapid particle growth and coalescence were observed.

Dmowski, Wojtek; Yin, Hongfeng; Dai, Sheng; Overbury, Steven H.; Egami, Takeshi (Tennessee-K); (ORNL)

2010-05-04T23:59:59.000Z

402

Characterization of the polymer-filler interface in (gamma)-irradiated silica-reinforced polysiloxane composites  

DOE Green Energy (OSTI)

The changes in hydrogen bonding at the interface of silica-reinforced polysiloxane composites due to aging in gamma radiation environments were examined in this study. Solvent swelling was utilized to determine the individual contributions of the matrix polymer and polymer-filler interactions to the overall crosslink density. The results show how the polymer-filler hydrogen bonding dominates the overall crosslink density of the material. Air irradiated samples displayed decreased hydrogen bonding at the polymer-filler interface, while vacuum irradiation revealed the opposite effect.

Chien, A T; Balazs, B; LeMay, J

2000-04-03T23:59:59.000Z

403

Femtosecond laser pulse filamentation under anomalous dispersion in fused silica. Part 1. Numerical investigation  

SciTech Connect

We report the results of investigation of femtosecond laser pulse filamentation in fused silica by varying the wavelength in the range from 800 to 2300 nm. It is shown that in the case of the anomalous group-velocity dispersion, a sequence of 'light bullets' with a high spatial and temporal localisation of the light field is formed along the filament. The relation of the formation and propagation of light bullets with the formation of an isolated anti-Stokes wing of the supercontinuum spectrum is established. (nonlinear optical phenomena)

Smetanina, E O; Kompanets, V O; Chekalin, Sergei V; Kandidov, V P

2012-10-31T23:59:59.000Z

404

Silica Deposition in Field and Laboratory Thermal Tests of Yucca Mountain Tuff  

SciTech Connect

A field thermal test was conducted by the Yucca Mountain Site Characterization Project to observe changes in the Topopah Spring Tuff middle nonlithophysal zone geohydrologic system due to thermal loading. A laboratory-scale crushed-tuff hydrothermal column test was used to investigate the tuff as a potential construction material within a nuclear-waste repository. Results of similar column tests have been cited as indications that silica deposition would plug the rock fractures above a repository and create unfavorable drainage conditions. Data from field and laboratory tests are used here to predict the magnitude of fracture sealing. For the crushed-tuff column test, a one-meter-high column was packed with crushed tuff to a porosity of about 50%. Water filling the lowermost 10 cm of the column was boiled and the vapor condensed at the top of the column, percolating down to the boiling zone. After 100 days, intergranular pore space in the saturated portion of the column was almost filled with amorphous silica. The Drift Scale Test at Yucca Mountain is a heating test in the unsaturated zone. It consists of a four-year heating phase, now complete, followed by a four-year cooling phase. Heaters in a 60-m-long drift and in the adjacent rock have heated the drift walls to 200 C. As the rock was heated, fluids naturally present in the rock migrated away from the heat sources. A boiling zone now separates an inner dry-out zone from an outer condensation zone. A heat-pipe region exists in the outer margin of the boiling zone above the heated drift. Amorphous silica coatings up to a few micrometers thick were deposited in this region. Deposits were observed in less than 10% of the fractures in the heat pipe region. Drift-scale test results yield a silica deposition rate of about 250 {micro}m/1000 years in 10% of the fractures in the heat-pipe region. We did not calculate deposition rates from our column test, but a rate of 9.1 mm/1000 years in all fractures of the heat-pipe region is predicted by Sun and Rimstidt (2002) from the results of a similar test. We believe the rate based on field-test observations is a better prediction because the field test more closely resembles the expected environment in a repository. Rates based on column-test results may be reasonable for local zones of preferred fluid flow.

S.S. Levy; S.J. Chipera; M.G. Snow

2002-08-30T23:59:59.000Z

405

Comparison of artificial neural network and fuzzy logic models for prediction of long-term compressive strength of silica fume concrete  

Science Conference Proceedings (OSTI)

In this study, an artificial neural network (ANN) and fuzzy logic (FL) study were developed to predict the compressive strength of silica fume concrete. A data set of a laboratory work, in which a total of 48 concretes were produced, was utilized in ... Keywords: Compressive strength, Concrete, Fuzzy logic, Neural networks, Silica fume

Fatih Özcan; Cengiz D. Ati?; Okan Karahan; Erdal Uncuo?lu; Harun Tanyildizi

2009-09-01T23:59:59.000Z

406

SILICA GEL BEHAVIOR UNDER DIFFERENT EGS CHEMICAL AND THERMAL CONDITIONS: AN EXPERIMENTAL STUDY  

Science Conference Proceedings (OSTI)

Fractures and fracture networks are the principal pathways for migration of water and contaminants in groundwater systems, fluids in enhanced geothermal systems (EGS), oil and gas in petroleum reservoirs, carbon dioxide leakage from geological carbon sequestration, and radioactive and toxic industrial wastes from underground storage repositories. When dealing with EGS fracture networks, there are several major issues to consider, e.g., the minimization of hydraulic short circuits and losses of injected geothermal fluid to the surrounding formation, which in turn maximize heat extraction and economic production. Gel deployments to direct and control fluid flow have been extensively and successfully used in the oil industry for enhanced oil recovery. However, to the best of our knowledge, gels have not been applied to EGS to enhance heat extraction. In-situ gelling systems can either be organic or inorganic. Organic polymer gels are generally not thermostable to the typical temperatures of EGS systems. Inorganic gels, such as colloidal silica gels, however, may be ideal blocking agents for EGS systems if suitable gelation times can be achieved. In the current study, we explore colloidal silica gelation times and rheology as a function of SiO{sub 2} concentration, pH, salt concentration, and temperature, with preliminary results in the two-phase field above 100 C. Results at 25 C show that it may be possible to choose formulations that will gel in a reasonable and predictable amount of time at the temperatures of EGS systems.

Hunt, J D; Ezzedine, S M; Bourcier, W; Roberts, S

2012-01-19T23:59:59.000Z

407

Study of a Threshold Cherenkov Counter Based on Silica Aerogels with Low Refractive Indices  

E-Print Network (OSTI)

To identify $\\pi^{\\pm}$ and $K^{\\pm}$ in the region of $1.0\\sim 2.5$ GeV/c, a threshold Cherenkov counter equipped with silica aerogels has been investigated. Silica aerogels with a low refractive index of 1.013 have been successfully produced using a new technique. By making use of these aerogels as radiators, we have constructed a Cherenkov counter and have checked its properties in a test beam. The obtained results have demonstrated that our aerogel was transparent enough to make up for loss of the Cherenkov photon yield due to a low refractive index. Various configurations for the photon collection system and some types of photomultipliers, such as the fine-mesh type, for a read out were also tested. From these studies, our design of a Cherenkov counter dedicated to $\\pi / K$ separation up to a few GeV/c %in the momentum range of $1.0 \\sim 2.5$ GeV/c with an efficiency greater than $90$ \\% was considered.

I. Adachi et al

1994-12-13T23:59:59.000Z

408

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

409

High resolution transmission electron microscopy of melamine-formaldehyde aerogels and silica aerogels  

Science Conference Proceedings (OSTI)

The goal of the high resolution transmission electron microscopy (HRTEM) was to image the structure of two tetramethyl orthosilicate (TMOS) and two melamine-formaldehyde (MF) aerogels at the single polymer chain level{sup 1,2}. With this level of structural resolution we hoped to interrelate each aerogel's structure with its physical properties and its method of synthesis. Conventional single-step base catalysed TMOS aerogels show strings of spheroidal particles linked together with minimal necking. The spheroidal particles range from 86--132 {Angstrom} and average 113{plus minus}10 {Angstrom} in diameter{sup 2}. In contrast the TMOS aerogels reported on here were made by a two step method. After extended silica chains are grown in solution under acidic conditions with a substoichiometric amount of water, the reaction is stopped and the methanol hydrolysed from TMOS is removed. Then base catalysis and additional water are added to cause gel formation is a nonalcoholic solvent. The MF aerogels were prepared for HRTEM by fracturing them on a stereo microscope stage with razor knife so that fractured pieces with smooth flat surfaces could be selected for platinum-carbon replication. The two silica (TMOS) aerogels were both transparent and difficult to see. These aerogels were fractured on a stereo microscope stage with tweezers. 6 refs., 4 figs.

Ruben, G.C. (Dartmouth Coll., Hanover, NH (United States). Dept. of Biological Sciences)

1991-09-01T23:59:59.000Z

410

SYNTHESIS OF OXYGENATED PRODUCTS FROM CARBON MONOXIDE AND HYDROGEN OVER SILICA- AND ALUMINA-SUPPORTED RUTHENIUM CATALYSTS  

E-Print Network (OSTI)

Formation Over a 1.01; Ru/A1 o Catalyst at 498K H/CO P (atm)a silica-supported Ru catalyst Fig. 2 Effect of feed flowan alumina-supported Ru catalyst Fig. 3 Effect of reaction

Kellner, C.Stephen

2013-01-01T23:59:59.000Z

411

Molecular Dynamics Studies on the Effects of Water Speciation on Interfacial Structure and Dynamics in Silica-Filled PDMS Composites  

DOE Green Energy (OSTI)

Significant changes in materials properties of siloxane based polymers can be obtained by the addition of inorganic fillers. In silica-filled polydimethylsiloxane (PDMS) based composites the mechanism of this reinforcing behavior is presumably hydrogen bonding between surface hydroxyls and backbone siloxane species. We have chosen to investigate in detail the effect of chemisorbed and physisorbed water on the interfacial structure and dynamics in silica-filled PDMS based composites. Toward this end, we have combined molecular dynamics simulations and experimental studies employing DMA and Nh4R analysis. Our results suggest that the polymer-silica contact distance and the mobility of interfacial polymer chains significantly decreased as the hydration level at the interface was reduced. The reduced mobility of the PDMS chains in the interfacial domain reduced the overall, bulk, motional properties of the polymer, thus causing an effective ''stiffening'' of the polymer matrix. The role of the long-ranged Coulombic interactions on the structural features and chain dynamics of the polymer were also examined. Both are found to be strongly influenced by the electrostatic interactions as identified by the bond orientation time correlation function and local density distribution functions. These results have important implications for the design of nanocomposite silica-siloxane materials.

Gee, R H; Maxwell, R S; Dinh, L N; Balazs, B

2001-11-21T23:59:59.000Z

412

Reducing Logistics Footprints and Replenishment Demands: Nano-engineered Silica Aerogels a Proven Method for Water Treatment  

SciTech Connect

Rapid deployment and the use of objective force aggressively reduce logistic footprints and replenishment demands. Maneuver Sustainment requires that Future Combat Systems be equipped with water systems that are lightweight, have small footprints, and are highly adaptable to a variety of environments. Technologies employed in these settings must be able to meet these demands. Lawrence Livermore National Laboratory has designed and previously field tested nano-engineered materials for the treatment of water. These materials have been either based on silica aerogel materials or consist of composites of these aerogels with granular activated carbon (GAC). Recent tests have proven successful for the removal of contaminants including uranium, hexavalent chromium, and arsenic. Silica aerogels were evaluated for their ability to purify water that had been spiked with the nerve agent VX (O-ethyl S-(2-diisopropylaminoethyl) methylphosphonothiolate). These results demonstrated that silica aerogels were able to remove the VX from the supply water and were nearly 30 times more adsorbent than GAC. This performance could result in REDUCING CHANGEOUT FREQUENCY BY A FACTOR OF 30 or DECREASING the VOLUME of adsorbent BY A FACTOR OF 30; thereby significantly reducing logistic footprints and replenishment demands. The use of the nano-engineered Silica Aerogel/GAC composites would provide a water purification technology that meets the needs of Future Combat Systems.

Daily, W; Coleman, S; Love, A; Reynolds, J; O'Brien, K; Gammon, S

2004-09-22T23:59:59.000Z

413

Durability of LDPE nanocomposites with clay, silica, and zinc oxide: part I: mechanical properties of the nanocomposite materials  

Science Conference Proceedings (OSTI)

Three types of LDPE-based nanocomposites with montmorillonite clay, silica, and zinc oxide were prepared by melt blending the nanofiller with the resin. As a prelude to studying their durability, the extent of reinforcement of the LDPE matrix by the ...

Halim Hamid Redhwi, Mohammad Nahid Siddiqui, Anthony L. Andrady, Syed Hussain

2013-01-01T23:59:59.000Z

414

A Big Response to a “Small” Problem: Identifying the Oxidative Potential of Nanomaterials and the Physicochemical Characteristics That Play a Role  

E-Print Network (OSTI)

Nanotechnology as a science is emerging rapidly. As materials are synthesized and utilized at the nanometer size scale, concerns of potential health and safety effects are arising. In an effort to elucidate the physicochemical characteristics of nanoparticles influential in toxicological studies, surface properties of metal oxide and carbonaceous nanoparticles were measured. These properties include zeta potential, dissolution and surface-bound chemical components. Subsequently, the role of these properties in oxidative stress was examined in vitro. This work identifies the influence that pH has on the zeta potential of nanoparticles. The zeta potential has the ability to alter colloidal stability, as the largest nanoparticle agglomerate is seen at or near the isoelectric point for each of the particles tested. Furthermore, it was observed that metal oxide nanoparticles which exhibit a charged surface at physiological pH, lead to decreased in vitro cellular viability as compared to those that were neutral. Thus, nanoparticle zeta potential may be an important factor to consider when attempting to predict nanoparticle toxicity. Real world exposure to nanoparticles is a mixture of various particulates and organics. Therefore, to simulate this particle mixture, iron oxide (Fe2O3) and engineered carbon black (ECB) were utilized in combination to identify potential synergistic reactions. Following in vitro exposure, both nanoparticle types are internalized into endosomes, where liberated Fe3+ reacts with hydroquinone moieties on the ECB surface yielding Fe2+. This bioavailable iron may then generate oxidative stress through intracellular pathways including the Fenton reaction. As oxidative stress is common in particulate toxicology, a comparison between the antioxidant defenses of epithelial (A549) and mesothelial (MeT-5A) cell lines was made. The A549 cell line exhibits alterations in the NRF2-KEAP1 transcription factor system and therefore retains high basal levels of phase II antioxidants. Both cell types were exposed to 33 nm silica where intracellular oxidant generation coupled with markers of oxidative stress were observed. While the MeT-5A cells exhibited a decrease in cell viability, the A549 cell line did not. Therefore, proper characterization of both material and biological systems prior to toxicity testing will help to further define the risks associated with the use of nanotechnology.

Berg, James Michael

2011-12-01T23:59:59.000Z

415

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

416

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 950°C is desirable, corresponding to SiO2:K2O of about 3:1. Mild chemical treatments were used to reduce Si, K, and Cl, while varying temperature, concentration, %-solids, and time. Dilute acid was more effective at removing K and Cl, while dilute alkali was more effective for Si. Reduction of minerals in this manner may prove economical for increasing utilization of the straw for combustion or gasification.

Thompson, David Neal; Lacey, Jeffrey Alan; Shaw, Peter Gordon

2002-04-01T23:59:59.000Z

417

Development of transparent silica aerogel over a wide range of densities  

E-Print Network (OSTI)

We have succeeded in developing hydrophobic silica aerogels over a wide range of densities (i.e. refractive indices). A pinhole drying method was invented to make possible producing highly transparent aerogels with entirely new region of refractive indices of 1.06-1.26. Obtained aerogels are more transparent than conventional ones, and the refractive index is well controlled in the pinhole drying process. A test beam experiment was carried out in order to evaluate the performance of the pinhole-dried aerogels as a Cherenkov radiator. A clear Cherenkov ring was successfully observed by a ring imaging Cherenkov counter. We also developed monolithic and hydrophobic aerogels with a density of 0.01 g/cm^3 (a low refractive index of 1.0026) as a cosmic dust capturer for the first time. Consequently, aerogels with any refractive indices between 1.0026 and 1.26 can be produced freely.

Makoto Tabata; Ichiro Adachi; Yoshikazu Ishii; Hideyuki Kawai; Takayuki Sumiyoshi; Hiroshi Yokogawa

2011-12-21T23:59:59.000Z

418

Tanpopo cosmic dust collector: Silica aerogel production and bacterial DNA contamination analysis  

E-Print Network (OSTI)

Hydrophobic silica aerogels with ultra-low densities have been designed and developed as cosmic dust capture media for the Tanpopo mission which is proposed to be carried out on the International Space Station. Glass particles as a simulated cosmic dust with 30 \\mu m in diameter and 2.4 g/cm^3 in density were successfully captured by the novel aerogel at a velocity of 6 km/s. Background levels of contaminated DNA in the ultra-low density aerogel were lower than the detection limit of a polymerase chain reaction assay. These results show that the manufactured aerogel has good performance as a cosmic dust collector and sufficient quality in respect of DNA contamination. The aerogel is feasible for the biological analyses of captured cosmic dust particles in the astrobiological studies.

Tabata, Makoto; Yokobori, Shin-ichi; Kawai, Hideyuki; Takahashi, Jun-ichi; Yano, Hajime; Yamagishi, Akihiko

2011-01-01T23:59:59.000Z

419

Development of transparent silica aerogel over a wide range of densities  

E-Print Network (OSTI)

We have succeeded in developing hydrophobic silica aerogels over a wide range of densities (i.e. refractive indices). A pinhole drying method was invented to make possible producing highly transparent aerogels with entirely new region of refractive indices of 1.06-1.26. Obtained aerogels are more transparent than conventional ones, and the refractive index is well controlled in the pinhole drying process. A test beam experiment was carried out in order to evaluate the performance of the pinhole-dried aerogels as a Cherenkov radiator. A clear Cherenkov ring was successfully observed by a ring imaging Cherenkov counter. We also developed monolithic and hydrophobic aerogels with a density of 0.01 g/cm^3 (a low refractive index of 1.0026) as a cosmic dust capturer for the first time. Consequently, aerogels with any refractive indices between 1.0026 and 1.26 can be produced freely.

Tabata, Makoto; Ishii, Yoshikazu; Kawai, Hideyuki; Sumiyoshi, Takayuki; Yokogawa, Hiroshi; 10.1016/j.nima.2010.02.241

2011-01-01T23:59:59.000Z

420

X-ray radiographic technique for measuring density uniformity of silica aerogel  

E-Print Network (OSTI)

This paper proposes a new X-ray radiographic technique for measuring density uniformity of silica aerogels used as radiator in proximity-focusing ring-imaging Cherenkov detectors. To obtain high performance in a large-area detector, a key characteristic of radiator is the density (i.e. refractive index) uniformity of an individual aerogel monolith. At a refractive index of n = 1.05, our requirement for the refractive index uniformity in the transverse plane direction of an aerogel tile is |\\delta (n - 1)/(n - 1)| aerogels from a trial production and that of Panasonic products (SP-50) as a reference, and to confirm they have sufficient density uniformity within \\pm 1% along the transverse plane direction. The measurement results show that the proposed technique can quantitatively estimate the density uniformity of aerogels.

Makoto Tabata; Yoshikiyo Hatakeyama; Ichiro Adachi; Takeshi Morita; Keiko Nishikawa

2012-12-14T23:59:59.000Z

Note: This page contains sample records for the topic "mesoporous silica nanomaterials" 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

Performance predictions of silica-gel desiccant dehumidifiers. Technical report No. 3  

SciTech Connect

The analysis of a cross-cooled desiccant dehumidifier using silica gel in the form of sheets is described. This unit is the principal component of solar powered desiccant air conditioning system. The mathematical model has first been formulated describing the dynamics of the dehumidifier. The model leads to a system of nonlinear coupled heat and mass transfer equations for the sorption processes and linear heat transfer equations for the purging processes. The model accounts for the gas film resistance and for the moisture diffusion in the desiccant. The governing equations are solved by a finite difference scheme to obtain periodic steady state solutions. The accuracy of the theoretical predictions is ascertained by comparing them with the experimental results. The performance of the dehumidifier, for a chosen set of initial conditions and dehumidifier parameters, has also been given.

Mathiprakasam, B.; Lavan, Z.

1980-01-01T23:59:59.000Z

422

An AC phase measuring interferometer for measuring dn/dT of fused silica and calcium fluoride at 193 nm  

Science Conference Proceedings (OSTI)

A novel method for the measurement of the change in index of refraction vs. temperature (dn/dT) of fused silica and calcium fluoride at the 193 nm wavelength has been developed in support of thermal modeling efforts for the development of 193 nm-based photolithographic exposure tools. The method, based upon grating lateral shear interferometry, uses a transmissive linear grating to divide a 193 nm laser beam into several beam paths by diffraction which propagate through separate identical material samples. One diffracted order passing through one sample overlaps the undiffracted beam from a second sample and forms interference fringes dependent upon the optical path difference between the two samples. Optical phase delay due to an index change from heating one of the samples causes the interference fringes to change sinusoidally with phase. The interferometer also makes use of AC phase measurement techniques through lateral translation of the grating. Results for several samples of fused silica and calcium fluoride are demonstrated.

Shagam, R.N.

1998-09-01T23:59:59.000Z

423

Effect of high silica content on scale deposition and pipe-wall loss in oilfield steam generators  

Science Conference Proceedings (OSTI)

Studies were conducted on site in the Coalinga, Belridge, and Midway Sunset fields in California to research the cause of metal losses detected in the radiant section return bends and immediate piping downstream form the stem generators. This paper reports on the surveillance of silica content in the influent and effluent streams of the selected steam generators and the results of X-ray inspection of bends, elbows, welds, and pipings which indicated that a correlation is likely to exist between the silica and bicarbonate concentration in the feedwater and the silicate scale buildup, and incident rate of wall loss and the cause of wall loss/pipe failures is a combination of corrosion and erosion mechanisms accelerated at higher steam qualities.

Khatib, Z.I.; Olson, E.E.; Place, M.C. Jr. (Shell Development Co., Houston, TX (United States))

1992-11-01T23:59:59.000Z

424

Electron-beam induced electric-hydraulic expansion in a silica-shelled gallium microball-nanotube structure  

Science Conference Proceedings (OSTI)

Heteroshape-heteroscale structure of silica-shelled Ga microball-nanotube was fabricated. Under in situ electron-beam irradiation, an abnormally large and fast expansion of Ga was observed. Failed by a sole routine heating effect of electron-beam, the expansion was explained by an electric-hydraulic expansion effect taking into account a huge inner pressure induced by the repelling Coulomb force of positively charged Ga ions on the Ga microball surface. The ions were accumulated due to knocking-out of Ga electrons under irradiation and shielding effect of a silica shell which prevents the charge balance restoration. A circuit model is proposed to calculate the accumulation of Ga ions.

Gao, Y. H.; Sun, M.; Su, J. [Wuhan National Laboratory for Optoelectronics (WNLO), School of Physics, College of Optoelectronic Science and Engineering, Huazhong University of Science and Technology (HUST), LuoyuRoad 1037, Wuhan 430074 (China); Zhi, C. Y.; Golberg, D.; Bando, Y. [International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), Namiki 1-1, Tsukuba, Ibaraki 305-0044 (Japan); Duan, X. F. [Institute of Physics, Beijing National Laboratory of Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190 (China)

2011-08-22T23:59:59.000Z

425

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

SciTech Connect

The wettability of silicon and glass surfaces can be modified by silanization. However, similar treatments of glass and silica surfaces using the same silane do not necessarily yield the same wettability as determined by the oil-water contact angle. In this technical note, surface cleaning pretreatments were investigated to determine conditions that would yield oil-wet surfaces on glass with similar wettability to silica surfaces treated with the same silane, and both air-water and oil-water contact angles were determined. Air-water contact angles were less sensitive to differences between silanized silica and glass surfaces, often yielding similar values while the oil-water contact angles were quite different. Borosilicate glass surfaces cleaned with standard cleaning solution 1 (SC1) yield intermediate-wet surfaces when silanized with hexamethyldisilazane, while the same cleaning and silanization yields oil-wet surfaces on silica. However, cleaning glass in boiling concentrated nitric acid creates a surface that can be silanized to obtain oil-wet surfaces using HDMS. Moreover, this method is effective on glass with prior thermal treatment at an elevated temperature of 400oC. In this way, silica and glass can be silanized to obtain equally oil-wet surfaces using HMDS. It is demonstrated that pretreatment and silanization is feasible in silicon-silica/glass micromodels previously assembled by anodic bonding, and that the change in wettability has a significant observable effect on immiscisble fluid displacements in the pore network.

Grate, Jay W.; Warner, Marvin G.; Pittman, Jonathan W.; Dehoff, Karl J.; Wietsma, Thomas W.; Zhang, Changyong; Oostrom, Martinus

2013-08-05T23:59:59.000Z

426

Eighth CANMET/ACI International Conference on Fly Ash, Silica Fume, Slag, and Natural Pozzolans in Concrete  

Science Conference Proceedings (OSTI)

The nine papers in this CD are collected by the U. S. Advisory Committee for presentation at the Eighth CANMET/ACI International Conference on Fly Ash, Silica Fume, Slag, and Natural Pozzolans in Concrete, May 23–29, 2004, Las Vegas, Nevada. They are being published by EPRI, Palo Alto, CA to make them available to all attendees, and other interested people, in a compact form for future reference and use.

2004-05-05T23:59:59.000Z

427

Helium Adsorption in Silica Aerogel near the Liquid-Vapor Critical Point  

E-Print Network (OSTI)

We have investigated the adsorption and desorption of helium near its liquid-vapor critical point in silica aerogels with porosities between 95 % and 98%. We used a capacitive measurement technique which allowed us to probe the helium density inside the aerogel directly, even though the samples were surrounded by bulk helium. The aerogel’s very low thermal conductivity resulted in long equilibration times so we monitored the pressure and the helium density, both inside the aerogel and in the surrounding bulk, and waited at each point until all had stabilized. Our measurements were made at temperatures far from the critical point, where a well defined liquid-vapor interface exists, and at temperatures up to the bulk critical point. Hysteresis between adsorption and desorption isotherms persisted to temperatures close to the liquid-vapor critical point and there was no sign of an equilibrium liquid-vapor transition once the hysteresis disappeared. Many features of our isotherms can be described in terms of capillary condensation, although this picture becomes less applicable as the liquid-vapor critical point is approached and it is unclear how it can be applied to aerogels, whose tenuous structure includes a wide range of length scales. I.

Tobias Herman; James Day; John Beamish

2008-01-01T23:59:59.000Z

428

Compressed Silica Aerogels for the Study of Superfluid [superscript 3]He  

SciTech Connect

We have performed Small Angle X-ray Scattering (SAXS) on uniaxially strained aerogels and measured the strain-induced structural anisotropy. We use a model to connect our SAXS results to anisotropy of the {sup 3}He quasiparticle mean free path in aerogel. Measurements of the low temperature phase diagram of superfluid {sup 3}He in 98% aerogel indicate a stable B-phase and a metastable A-like phase. Vicente et al. proposed that the relative stability of these phases can be attributed to local anisotropic scattering of the 3He quasiparticles by the aerogel network. This network consists of silica strands with a diameter of {approx} 30 {angstrom} and average separation {zeta}{sub a} {approx} 300 {angstrom}. Vicente et al. also proposed using uniaxial strain of the aerogel to produce global anisotropy. We have performed SAXS on two uniaxially strained aerogels and found that strain introduces anisotropy on the {approx}100 {angstrom} length scale. We relate this to anisotropy of the quasiparticle mean free path, {lambda}.

Pollanen, J.; Choi, H.; Davis, J.P.; Blinstein, S.; Lippman, T.M.; Lurio, L.B.; Mulders, N.; Halperin, W.P. (NIU); (Delaware); (NWU)

2007-03-02T23:59:59.000Z

429

FUNCTIONALIZED SILICA AEROGELS: ADVANCED MATERIALS TO CAPTURE AND IMMOBILIZE RADIOACTIVE IODINE  

Science Conference Proceedings (OSTI)

To support the future expansion of nuclear energy, an effective method is needed to capture and safely store radiological iodine-129 released during reprocessing of spent nuclear fuel. Various materials have been investigated to capture and immobilize iodine. In most cases, however, the materials that are effective for capturing iodine cannot subsequently be sintered/densified to create a stable composite that could be a viable waste form. We have developed chemically modified, highly porous, silica aerogels that show sorption capacities higher than 440 mg of I2 per gram at 150 C. An iodine uptake test in dry air containing 4.2 ppm of iodine demonstrated no breakthrough after 3.5 h and indicated a decontamination factor in excess of 310. Preliminary densification tests showed that the I2-loaded aerogels retained more than 92 wt% of I2 after thermal sintering with pressure assistance at 1200 C for 30 min. These high capture and retention efficiencies for I2 can be further improved by optimizing the functionalization process and the chemistry as well as the sintering conditions.

Matyas, Josef; Fryxell, Glen E.; Busche, Brad J.; Wallace, Krys; Fifield, Leonard S.

2011-11-16T23:59:59.000Z

430

Helium adsorption in silica aerogel near the liquid-vapor critical point  

E-Print Network (OSTI)

We have investigated the adsorption and desorption of helium near its liquid-vapor critical point in silica aerogels with porosities between 95% and 98%. We used a capacitive measurement technique which allowed us to probe the helium density inside the aerogel directly, even though the samples were surrounded by bulk helium. The aerogel's very low thermal conductivity resulted in long equilibration times so we monitored the pressure and the helium density, both inside the aerogel and in the surrounding bulk, and waited at each point until all had stabilized. Our measurements were made at temperatures far from the critical point, where a well defined liquid-vapor interface exists, and at temperatures up to the bulk critical point. Hysteresis between adsorption and desorption isotherms persisted to temperatures close to the liquid-vapor critical point and there was no sign of an equilibrium liquid-vapor transition once the hysteresis disappeared. Many features of our isotherms can be described in terms of capillary condensation, although this picture becomes less applicable as the liquid-vapor critical point is approached and it is unclear how it can be applied to aerogels, whose tenuous structure includes a wide range of length scales.

Tobias Herman; James Day; John Beamish

2005-05-18T23:59:59.000Z

431

Tuning the properties of Ge-quantum dots superlattices in amorphous silica matrix through deposition conditions  

Science Conference Proceedings (OSTI)

In this work, we investigate the structural properties of Ge quantum dot lattices in amorphous silica matrix, prepared by low-temperature magnetron sputtering deposition of (Ge+SiO{sub 2})/SiO{sub 2} multilayers. The dependence of quantum dot shape, size, separation, and arrangement type on the Ge-rich (Ge + SiO{sub 2}) layer thickness is studied. We show that the quantum dots are elongated along the growth direction, perpendicular to the multilayer surface. The size of the quantum dots and their separation along the growth direction can be tuned by changing the Ge-rich layer thickness. The average value of the quantum dots size along the lateral (in-plane) direction along with their lateral separation is not affected by the thickness of the Ge-rich layer. However, the thickness of the Ge-rich layer significantly affects the quantum dot ordering. In addition, we investigate the dependence of the multilayer average atomic composition and also the quantum dot crystalline quality on the deposition parameters.

Pinto, S. R. C.; Ramos, M. M. D.; Gomes, M. J. M. [University of Minho, Centre of Physics and Physics Department, Braga 4710-057 (Portugal); Buljan, M. [Ruder Boskovic Institute, Bijenicka cesta 54, Zagreb 10000 (Croatia); Chahboun, A. [University of Minho, Centre of Physics and Physics Department, Braga 4710-057 (Portugal); Physics Department, FST Tanger, Tanger BP 416 (Morocco); Roldan, M. A.; Molina, S. I. [Departamento de Ciencia de los Materiales e Ing. Metalurgica y Q. I., Universidad de Cadiz, Cadiz (Spain); Bernstorff, S. [Sincrotrone Trieste, SS 14 km163, 5, Basovizza 34012 (Italy); Varela, M.; Pennycook, S. J. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Barradas, N. P.; Alves, E. [Instituto Superior Tecnico e Instituto Tecnologico e Nuclear-, EN10, Sacavem 2686-953 (Portugal)

2012-04-01T23:59:59.000Z

432

Tuning the properties of Ge-quantum dots superlattices in amorphous silica matrix through deposition conditions  

Science Conference Proceedings (OSTI)

In this work, we investigate the structural properties of Ge quantum dot lattices in amorphous silica matrix, prepared by low-temperature magnetron sputtering deposition of (Ge+SiO{sub 2})/SiO{sub 2} multilayers. The dependence of quantum dot shape, size, separation, and arrangement type on the Ge-rich (Ge + SiO{sub 2}) layer thickness is studied. We show that the quantum dots are elongated along the growth direction, perpendicular to the multilayer surface. The size of the quantum dots and their separation along the growth direction can be tuned by changing the Ge-rich layer thickness. The average value of the quantum dots size along the lateral (in-plane) direction along with their lateral separation is not affected by the thickness of the Ge-rich layer. However, the thickness of the Ge-rich layer significantly affects the quantum dot ordering. In addition, we investigate the dependence of the multilayer average atomic composition and also the quantum dot crystalline quality on the deposition parameters.

Pinto, S. [University of Minho, Portugal; Roldan Gutierrez, Manuel A [ORNL; Ramos, M. M.D. [University of Minho, Portugal; Gomes, M.J.M. [University of Minho, Portugal; Molina, S. I. [Universidad de Cadiz, Spain; Pennycook, Stephen J [ORNL; Varela del Arco, Maria [ORNL; Buljan, M. [R. Boskovic Institute, Zagreb, Croatia; Barradas, N. [Instituto Tecnologico e Nuclear (ITN), Lisbon, Portugal; Alves, E. [Instituto Tecnologico e Nuclear (ITN), Lisbon, Portugal; Chahboun, A. [FST Tanger, Morocco; Bernstorff, S. [Sincrotrone Trieste, Basovizza, Italy

2012-01-01T23:59:59.000Z

433

Pyrolysis and hydropyrolysis of diphenylmethane and sulphur-containing compounds immobilised on silica  

DOE Green Energy (OSTI)

The use of high pressures and dispersed catalysts, such as sulphided molybdenum (Mo) in fixed-bed hydropyrolysis of coals give rise to increased tar yields. In order to improve our understanding of these phenomena, Particularly in relation to cleavage of C-C and C-S bonds, experiments have been conducted on samples of silica-immobilised benzene, diphenylmethane, thioanisole and dibenzothiophene (DBT). These model substrates have the inherent advantage that they do not soften and thus stay in the reactor. Moreover, for the surface-immobilized benzene, the SiO-C bond linking the substrate to the surface is reasonably stable and does not show significant cleavage until 550{degrees}C (peak maximum) with a high yield of benzene being achieved at 150 bar hydrogen pressure. For the diphenylmethane substrate, the use of 150 bar hydrogen pressure and the Mo catalyst both reduced the peak evolution temperatures for benzene and toluene clearly demonstrating their separate contributions to promoting C-C bond cleavage. Desulphurisation of the DBT substrate occurred only in hydrogen and the thermal decomposition of the thioanisole substrate was altered markedly by the Mo catalyst.

Mitchell, S.C.; Lafferty, C.J.; Garcia, R.; Ismail, K.; Snape, C.E. [Strathclyde Univ., Glasgow (United Kingdom). Dept. of Pure and Applied Chemistry; Buchanan, A.C. III; Britt, P.F. [Oak Ridge National Lab., TN (United States); Klavetter, E. [Sandia National Labs., Albuquerque, NM (United States); en

1992-08-01T23:59:59.000Z

434

Thermal and solar-optical properties of silica aerogel for use in insulated windows  

SciTech Connect

Silica aerogel is a porous insulating material that is transport to solar radiation. To understand its insulating performance in a window system, it is necessary to first study component heat transfer paths. Aerogel's absorption coefficient, a measure of the attenuation of radiation heat transfer, was determined over the spectral range 1-200 ..mu..m. Although radiation heat transfer is negligible over much of this region, there is a transmission window between 3-6 ..mu..m. At ambient temperatures, for aerogel thicknesses of 0.5-5.0 cm, radiation heat transfer through an unmodified aerogel window is less than 15% of the total heat flux. For evacuated or high-temperature furnace windows, this contribution can be over 50%. Thermal radiative transfer can be somewhat decreased by allowing the aerogel to absorb moisture, but solar transmission and optical clarity are sacrificed. Absorption of water vapor over time causes irreversible structural changes that increase scattering in the solar spectrum. Aerogel's thermal performance can be improved by replacing the pore gas with one of lower conductivity or by evacuating the aerogel to pressure below 0.1 atm. A hypothetical evacuated aerogel window has a calcuated U-Value of approx. =0.5 W/m/sup 2/-K for a gap spacing of 12.5 mm, which is four times better than currently available low-emissivity gas-filled units of similar size. 8 refs., 9 figs.

Hartmann, J.; Rubin, M.; Arasteh, D.

1987-06-01T23:59:59.000Z

435

Elastic properties of silica aerogels from a new rapid supercritical extraction process  

Science Conference Proceedings (OSTI)

Silica aerogels were produced by a new process from Tetramethoxysilane (TMOS) with ammonia as base catalyst. the process involves pouring the liquid sol in a stainless steel mold and immediately heating it to supercritical conditions. Gelation and aging occurs during heating and reaction rates are high die to high average temperatures. the gel fills the container completely, which enables relatively fast venting of the supercritical fluid by providing a constraint for swelling and failure of the gel monolith. The whole process can be completed in 6 h or less. Longitudinal and shear moduli were measured in the dried aerogels by ultrasonic velocity measurements both as a function of chemical composition of the original sol and of position in the aerogel. It was found that the sound velocity exhibits marked maxima on the surface of the cylindrical specimens and specifically close to the ends, where the fluid left during venting. Specimens with high catalyst concentration and high water:TMOS ratio exhibited higher average moduli.

Gross, J.; Coronado, P.R.; Hair, L.M.; Hrubesh, L.W.

1997-08-11T23:59:59.000Z

436

Corrugation of Phase-Separated Lipid Bilayers Supported by Nanoporous Silica Xerogel Surfaces  

Science Conference Proceedings (OSTI)

Lipid bilayers supported by substrates with nanometer-scale surface corrugations holds interest in understanding both nanoparticle-membrane interactions and the challenges of constructing models of cell membranes on surfaces with desirable properties, e.g. porosity. Here, we successfully form a two-phase (gel-fluid) lipid bilayer supported by nanoporous silica xerogel. Surface topology, diffusion, and lipid density in comparison to mica-supported lipid bilayers were characterized by AFM, FRAP, FCS, and quantitative fluorescence microscopy, respectively. We found that the two-phase lipid bilayer follows the xerogel surface contours. The corrugation imparted on the lipid bilayer results in a lipid density that is twice that on a flat mica surface. In direct agreement with the doubling of actual bilayer area in a projected area, we find that the lateral diffusion coefficient (D) of lipids on xerogel ({approx}1.7 {micro}m{sup 2}/s) is predictably lower than on mica ({approx}4.1 {micro}m{sup 2}/s) by both FRAP and FCS techniques. Furthermore, the gel-phase domains on xerogel compared to mica were larger and less numerous. Overall, our results suggest the presence of a relatively defect-free continuous two-phase bilayer that penetrates approximately midway into the first layer of {approx}50 nm xerogel beads.

Goksu, E I; Nellis, B A; Lin, W; Satcher Jr., J H; Groves, J T; Risbud, S H; Longo, M L

2008-10-30T23:59:59.000Z

437

The effect of particle-particle interaction forces on the flow properties of silica slurries  

SciTech Connect

Preliminary work has been completed to investigate the effect of particle-particle interaction forces on the flow properties of silica slurries. Classically hydro-transport studies have focused on the flow of coarse granular material in Newtonian fluids. However, with current economical and environmental pressures, the need to increase solid loadings in pipe flow has lead to studies that examine non-Newtonian fluid dynamics. The flow characteristics of non-Newtonian slurries can be greatly influenced through controlling the solution chemistry. Here we present data on an 'ideal' slurry where the particle size and shape is controlled together with the solution chemistry. We have investigated the effect of adsorbed cations on the stability of a suspension, the packing nature of a sediment and the frictional forces to be overcome during re-slurrying. A significant change in the criteria assessed was observed as the electrolyte concentration was increased from 0.1 mM to 1 M. In relation to industrial processes, such delicate control of the slurry chemistry can greatly influence the optimum operating conditions of non-Newtonian pipe flows. (authors)

Harbottle, David; Fairweather, Michael; Biggs, Simon [Institute of Particle Science and Engineering, School of Process, Environmental and Materials Engineering, University of Leeds, UK, LS2 9JT (United Kingdom); Rhodes, Dominic [Nexia Solutions, Sellafield, Cumbria (United Kingdom)

2007-07-01T23:59:59.000Z

438

NCNR BT5-USANS Instrument Schedule D. Mildner Tel: (301) ...  

Science Conference Proceedings (OSTI)

... U19-01 formation of mesoporous (Lund U) silica - USANS May 31 1 I. Lini (South 6312 Scattering Study of the 5P Jackson Dakota State) NIST Clay ...

439

Corrections for Measurements of Tritium in Subterranean Vapor using Silica Gel  

Science Conference Proceedings (OSTI)

Hazardous contaminants buried within vadose zones can accumulate in soil gas. The concentrations and spatial extent of these contaminants are measured to evaluate potential transport to ground water for public risk evaluation. Tritium is an important contaminant found in and monitored for in vadose zones across numerous sites within the United States nuclear weapons complex, including Los Alamos National Laboratory. The extraction, collection, and laboratory analysis of tritium from subterranean soil gas presents numerous technical challenges that have not been fully studied. Particularly, the lack of soil moisture in the soil gas in the vadose zone makes it difficult to obtain enough sample moisture (e.g., > 5 g) to provide for the required sensitivity, and often, only small amounts of moisture can be collected. Further, although silica gel has high affinity for water vapor and is prebaked prior to sampling, there is still sufficient residual moisture in the prebaked gel to dilute the relatively small amount of sampled moisture; thereby, significantly lowering the 'true' tritium concentration in the soil gas. This paper provides an evaluation of the magnitude of the bias from dilution, provides methods to correct past measurements by applying a correction factor (CF), and evaluates the uncertainty of the CF values. For this, ten-thousand Monte Carlo calculations were perfonned and distribution parameters of CF values were detennined and evaluated. The mean and standard deviation of the distribution of CF values were 1.53 {+-} 0.36, and the minimum, median, and maximum values were 1.14, 1.43, and 5.27, respectively.

Whicker, Jeffrey [Los Alamos National Laboratory; Dewart, Jean M [Los Alamos National Laboratory; Allen, Shannon P [Los Alamos National Laboratory; Eisele, William F [Los Alamos National Laboratory; Mcnaughton, Michael C [Los Alamos National Laboratory; Green, Andrew A [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

440

The Deep-Sea Natural Products, Biogenic Polyphosphate (Bio-PolyP) and Biogenic Silica (Bio-Silica), as Biomimetic Scaffolds for Bone Tissue Engineering: Fabrication of a Morphogenetically-Active Polymer  

E-Print Network (OSTI)

Abstract: Bone defects in human, caused by fractures/nonunions or trauma, gain increasing impact and have become a medical challenge in the present-day aging population. Frequently, those fractures require surgical intervention which ideally relies on autografts or suboptimally on allografts. Therefore, it is pressing and likewise challenging to develop bone substitution materials to heal bone defects. During the differentiation of osteoblasts from their mesenchymal progenitor/stem cells and of osteoclasts from their hemopoietic precursor cells, a lineage-specific release of growth factors and a trans-lineage homeostatic cross-talk via signaling molecules take place. Hence, the major hurdle is to fabricate a template that is functioning in a way mimicking the morphogenetic, inductive role(s) of the native extracellular matrix. In the last few years, two naturally occurring polymers that are produced by deep-sea sponges, the biogenic polyphosphate (bio-polyP) and biogenic silica (bio-silica) have also been identified as promoting morphogenetic on both osteoblasts andMar. Drugs 2013, 11 719

Xiaohong Wang; Heinz C. Schröder; Qingling Feng; Florian Draenert; Werner E. G. Müller

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "mesoporous silica nanomaterials" 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

Single crystalline mesoporous silicon nanowires  

E-Print Network (OSTI)

Semiconductor Chalcogenide Aerogels. Sun, D. ; Riley, A.H. , Hexagonal gels and aerogels from chalcogenide clusters.

Hochbaum, Allon

2010-01-01T23:59:59.000Z

442

Single crystalline mesoporous silicon nanowires  

E-Print Network (OSTI)

semiconducting gels and aerogels from chalcogenide clusters.243 - 246. Chalcogenide Aerogels. Science 2005, 307, 397-

Hochbaum, A.I.

2010-01-01T23:59:59.000Z

443

Controlled Processing of Mesoporous ??Fe  

Science Conference Proceedings (OSTI)

The liquid mixtures were processed into amorphous solid foams in a microwave oven under controlled sensor heating process. Based on TGA/DSC experiments

444

Mesoporous Block Copolymer Battery Separators  

E-Print Network (OSTI)

is ~1-2 $ kg -1 , the cost of battery separators is ~120-240greatly reduce the cost of battery separators. Our approach1-2 $ kg -1 , the cost of a typical battery separator is in

Wong, David Tunmin

2012-01-01T23:59:59.000Z

445

Mesoporous Block Copolymer Battery Separators  

E-Print Network (OSTI)

at the Advanced Photon Source (APS). 15 The azimuthallyat the Advanced Photon Source (APS). 15 The azimuthally

Wong, David Tunmin

2012-01-01T23:59:59.000Z

446

Experimental and numerical study of the effective thermal conductivity of silica nanocomposites with thermal boundary resistance  

SciTech Connect

The thermal interface resistance at the macro scale is mainly described by the physical gap between two interfaces and constriction resistance due to this gap. The small gaps between the two material faces makes up the majority of thermal interface resistance at the macro scale. So, most of the studies have been focused on characterizing effect of surface geometry and material properties to thermal interface resistance. This resistance is more widely known as thermal contact resistance, represented with Rc. There are various models to predict thermal contact resistance at macro scale. These models predict thermal resistance Rc for given two materials by utilizing their bulk thermomechanical properties. Although, Rc represents thermal resistance accurately for macro size contacts between two metals, it is not suitable to describe interface resistance of particles in modern TIMs, aka particulate composites. The particles inside recently available TIMs are micron size and with effort to further increase surface area this particle size is approaching nano scale. At this small scale, Rc does not accurately predict thermal interface, as it is very difficult to characterize the surface topography. The thermal discontinuity at perfectly bonded interface of two dissimilar materials is termed as thermal boundary resistance (Rb) or Kapitza resistance. The macroscopic assumptions that thermal discontinuity only exists due to gaps and surface geometry leads to substantial error in determining interface thermal properties at micron and nano scale. The phenomenon of thermal boundary resistance is an inherent material property and arises due to fundamental mechanism of thermal transport. For metal-matrix particulate composites, Rb plays more important role than Rc. The free flowing nature of the polymer would eliminate most of the gaps between the two materials at their interface. This means almost all of the thermal resistance at particle/matrix interface would occur due to Rb. The current study presents experimental study of thermal boundary resistance for silica nano particles embedded inside epoxy resin. The bulk conductivity of the sample is measured and Rc is back calculated using Hasselman-Johnson s (H-J) equation. The numerical validation of the equation is also presented, including extrapolation study to predict effective conductivity of the nanocomposite TIM.

Kothari, Rushabh M [ORNL; Dinwiddie, Ralph Barton [ORNL; Wang, Hsin [ORNL

2013-01-01T23:59:59.000Z

447

The Effects of Using Alkali-Silica Reaction Affected Recycled Concrete Aggregate in Hot Mix Asphalt  

E-Print Network (OSTI)

The effects of using alkali-silica reaction (ASR) affected recycled concrete aggregate (ASR-RCA) in hot mix asphalt (HMA) were investigated in this study. Dilatometer and modified beam tests were performed to determine the possibility of new ASR occurring in reactive aggregates within the HMA or re-expansion of existing gel. The Lottman test and micro-calorimeter were used to determine the moisture susceptibility of HMA made with ASR-RCA. A differential scanning calorimeter (DSC) with thermogravimetric analysis (TGA) was used to evaluate the drying of an artificial gel and x-ray diffraction (XRD) was used to check for the potential presence of gel in the filler fraction of the ASR-RCAs. Micro-deval and freeze-thaw tests were evaluated for their potential to indicate the presence of excess micro-cracks or ASR gel. Expansion testing indicated that both ASR-RCAs were still reactive with 0.5 N NaOH solution saturated with calcium hydroxide (CH) at 60 degrees C. Dilatometer testing of HMA specimens in NaOH CH solution at 60 degrees C indicated a reaction between the asphalt binder and the solution, but little, if any, ASR. The lack of expansion in the modified beam test supports the binder-solution interaction. However, dilatometer testing in deicer solution at the same temperature indicated that some ASR may have occurred along with the primary binder-solution interaction. The volume change characteristics associated with the binder-solution interaction with and without ASR was supported by the change in pH and alkali concentration of the test solution. DSC/TGA testing indicated that the artificial gel dehydrated at approximately 100 degrees C. XRD analysis of the filler indicated that some gel may have accumulated in this fraction. Moisture damage testing indicated good resistance to moisture damage by HMA mixtures made with ASR-RCA especially compared to a virgin siliceous aggregate. Micro-deval and freeze-thaw tests can detect the presence of micro-cracks due to ASR in ASR-RCAs as higher mass loss than the virgin aggregate. The potential distress mechanisms that may occur when using ASR-RCA in an HMA pavement were identified. Results obtained using accelerated laboratory conditions were extrapolated based on anticipated field conditions. Guidelines for the mitigation of potential distresses in HMA made with ASR-RCA are presented.

Geiger, Brian James

2010-08-01T23:59:59.000Z

448

Structural Assessment of D-Regions Affected by Alkali-Silica Reaction/Delayed Ettringite Formation  

E-Print Network (OSTI)

A combined experimental and analytical program was conducted to investigate the effects of Alkali-Silica Reaction (ASR) and Delayed Ettringite Formation (DEF) on D-regions in reinforced concrete (RC) bridge bents. Four large-scale RC specimens, which represent cantilever and straddle bents in Texas bridges in each specimen, were constructed. The first specimen represented the unexposed control specimen, while the other three were conditioned in the field with supplemental watering to promote ASR/DEF and served as the exposed specimens. The control and two exposed specimens with various levels of ASR/DEF, after eight months and two years of field conditioning, were load tested to failure. The last specimen remains in field with additional exposure to promote ASR/DEF and will be load tested in future studies. The width and length of preload-induced cracks and developing cracks that initiated in the exposed specimens and grew over time, indicating concrete expansion due to ASR/DEF mechanisms, were measured. Petrographic analysis results of concrete cores extracted from the exposed specimens after their load testing confirmed the formation of ASR gel and minimum accumulation of ettringite. The structural testing results showed that the failure mechanism in all three tested specimens was due to a brittle shear failure in the beam-column joint. However, slightly greater stiffness, strength, and ductility were observed in the exposed specimens as a result of the activation of the reinforcing steel in the specimens due to the expansion of the concrete primarily from ASR, which effectively prestressed and confined the core concrete. Sectional analysis and Strut-and-Tie Modeling (STM) of the experimental specimens were applied. Three-dimensional nonlinear Finite Element Analyses (FEA) were also conducted to numerically simulate the overall structural performance, internal response, and out-of-plane behavior of the experimental specimens. The effects of varying constitutive relations of the concrete in tension on models of the specimens were compared with the measured experimental response. A method to mimic ASR/DEF effects on exposed specimens was proposed and incorporated into the FEA approach. As a result, forces that prestress and confine the core concrete were effectively applied through the reinforcing steel prior to subsequent structural loading. The three-dimensional FEA approach was able to simulate the out-of-plane behavior of the beam-column joint and the proposed method yielded comparable results with the measured overall and internal behavior of specimens.

Liu, Shih-Hsiang 1979-

2012-12-01T23:59:59.000Z

449

Compressive Creep Performance and High Temperature Dimensional Stability of Conventional Silica Refractories  

Science Conference Proceedings (OSTI)

Furnace designers and refractory engineers recognize that optimized furnace superstructure design and refractory selection are needed as glass production furnaces are continually striving toward greater output and efficiencies. Harsher operating conditions test refractories to the limit, while changing production technology (such as the conversion to oxy-fuel from traditional air-fuel firing) can alter the way the materials perform. Refractories for both oxy- and air-fuel fired furnace superstructures are subjected to high temperatures during service that may cause them to excessively creep or subside if the refractory material is not creep resistant, or if it is subjected to high stress, or both. Furnace designers can ensure that superstructure structural integrity is maintained if the creep behavior of the refractory material is well understood and well represented by appropriate engineering creep models. Several issues limit the abilities of furnace designers to (1) choose the optimum refractory for their applications, (2) optimize the engineering design, or (3) predict the service mechanical integrity of their furnace superstructures. Published engineering creep data are essentially non-existent for almost all commercially available refractories used for glass furnace superstructures. The limited data that do exist are supplied by the various refractory suppliers. Unfortunately, these suppliers generally have different ways of conducting their mechanical testing and they also interpret and report their data differently; this makes it hard for furnace designers to draw fair comparisons between competing grades of candidate refractories. Furthermore, the refractory supplier's data are often not available in a form that can be readily used for furnace design and for the prediction and design of long-term structural integrity of furnace superstructures. With the aim of providing such comparable data, the US DOE's Office of Industrial Technology and its Advanced Industrial Materials program is sponsoring work to conduct creep testing and analysis on refractories of interest to the glass industry. An earlier stage of the project involved identifying which refractories to test and this is described elsewhere. Conventional silica was one such identified refractory category, and the present report describes the creep behavior of this class of refractories. To portray a more complete understanding of how these refractories perform at service temperatures, their fundamental corrosion resistances, dimensional stabilities, and microstructure were characterized as well.

Karakus, M.; Kirkland, T.P.; Liu, K.C.; Moore, R.E.; Pint, B.A.; Wereszczak, A.A.

1999-03-01T23:59:59.000Z

450

CO/sub 2/-silica geothermometer for low temperature geothermal resource assessment, with application to resources in the Safford Basin, Arizona  

DOE Green Energy (OSTI)

This study investigates silica-water reactions in low-temperature geothermal water in areas near Safford, southeastern Arizona, and derives a pCO2 correction for conductive silica geothermometers. Use and limitations of the technique are also discussed. Data collection, interpretation approach, and basic geochemistry, as it applies to this study, are outlined. In addition, the geology, thermal regime, geohydrology, and gross geochemistry of the Safford area are reviewed. Finally, geothermal potential, as indicated by this study and previous studies is discussed.

Witcher, J.C.; Stone, C.

1983-11-01T23:59:59.000Z

451

Experimental study of the performance of a laminar flow silica gel desiccant packing suitable for solar air conditioning application  

DOE Green Energy (OSTI)

An experimental study of the performance of a low pressure drop silica gel desiccant packing has been carried out. The packing is in the form of narrow passages lined with a single layer of small silica gel particles. A near optimum particle size of 0.25 mm, and a range of passage widths of 1.46 to 3.75 mm were chosen based on the predictions of a computer simulation model. A test chamber was constructed with sufficient thermal insulation to allow close to adiabatic conditions for the 12 cm x 12 cm cross section of packing. Step change adsorption and desorption tests were performed for various plate spacings, air flow rates, air inlet conditions, and gel initial water contents. Air outlet moisture content and temperature, as well as pressure drop were measured. The experimental results were compared with predictions of the computer simulation model: This model is based on gas side controlled heat and mass transfer, with the small solid side mass transfer resistance incorporated in a crude manner, and heat transfer into the packing handled as a lumped thermal capacitance. Reasonable agreement was obtained between theoretical prediction and experiment. The match was found to improve with increased passage width. The discrepancies are chiefly attributed to an excessive air bypass, and to inaccurate accounting for heat transfer from the sides of the unit. Use of the computer code for prototype scale design purposes is recommended.

Biswas, P.

1983-02-01T23:59:59.000Z

452

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

453

Cathodoluminescence microscopy and petrographic image analysis of aggregates in concrete pavements affected by alkali-silica reaction  

SciTech Connect

Various microscopic techniques (cathodoluminescence, polarizing and electron microscopy) were combined with image analysis with the aim to determine a) the modal composition and degradation features within concrete, and b) the petrographic characteristics and the geological types (rocks, and their provenance) of the aggregates. Concrete samples were taken from five different portions of Highway Nos. D1, D11, and D5 (the Czech Republic). Coarse and fine aggregates were found to be primarily composed of volcanic, plutonic, metamorphic and sedimentary rocks, as well as of quartz and feldspar aggregates of variable origins. The alkali-silica reaction was observed to be the main degradation mechanism, based upon the presence of microcracks and alkali-silica gels in the concrete. Use of cathodoluminescence enabled the identification of the source materials of the quartz aggregates, based upon their CL characteristics (i.e., color, intensity, microfractures, deformation, and zoning), which is difficult to distinguish only employing polarizing and electron microscopy. - Highlights: Black-Right-Pointing-Pointer ASR in concrete pavements on the Highways Nos. D1, D5 and D11 (Czech Republic). Black-Right-Pointing-Pointer Cathodoluminescence was combined with various microscopic techniques and image analysis. Black-Right-Pointing-Pointer ASR was attributed to aggregates. Black-Right-Pointing-Pointer Source materials of aggregates were identified based on cathodoluminescence characteristics. Black-Right-Pointing-Pointer Quartz comes from different volcanic, plutonic and metamorphic parent rocks.

Stastna, A., E-mail: astastna@gmail.com [Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University in Prague, Albertov 6, 128 43 Praha 2 (Czech Republic); Sachlova, S.; Pertold, Z.; Prikryl, R. [Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University in Prague, Albertov 6, 128 43 Praha 2 (Czech Republic); Leichmann, J. [Department of Geological Sciences, Faculty of Science, Masaryk University in Brno, Kotlarska 267/2, 611 37 Brno (Czech Republic)

2012-03-15T23:59:59.000Z

454

Aerogels: stiff foams composed of up to 99.8% air Silica aerogel is the world's lowest-density solid: 1 mg/cm3  

E-Print Network (OSTI)

#12;Aerogels: stiff foams composed of up to 99.8% air Silica aerogel is the world's lowest-density solid: 1 mg/cm3 Aerogels hold 15 different records for material properties, including best insulator 2.38 g piece of aerogel supports a 2.5 kg brick. #12;#12;#12;l = m Ã? n unit vector in orbital space

Fominov, Yakov

455

The sorption of thorium, protacintium and plutonium onto silica particles in the presence of a colloidal third phase  

E-Print Network (OSTI)

The fate of actinides in the environment is of interest for a several reasons. In oceanic surface waters actinides such as thorium and protactinium, and in particular their ratio, are used as tracers of processes such as boundary scavenging and paleocirculation. Thorium is also used to estimate residence times and particle and colloid fluxes from the euphotic zone, which is useful in global carbon budgets used to assess effects of global warming. Terrestrially, contaminated areas in need of remediation, such as former nuclear weapons production facilities, remain as repositories for no longer needed actinide stockpiles or waste by-products such as plutonium. All three of these actinides: thorium, protactinium, and plutonium are known to be particle-reactive but the extent to which they sorb to immobile particles and mobile colloids can vary with environmental conditions. Understanding controls on adsorption is important in understanding uses and any limitations of these radioactive tracers caused by colloids. Often laboratory studies to understand actinide behavior are conducted at concentrations (micro- to millimolar), which are orders of magnitude higher than they are found in the environment (femto- to picomolar). Colloids, a size class of particles operationally defined as 1 nm to 1 µm in size, are ubiquitous in aquatic systems. The effect colloids have on actinide particle association, i.e. competitive or enhancing, can have a profound influence on the ultimate behavior of the actinide. The overall aim of this study is to assess sorption of thorium, protactinium and plutonium onto silica particles as a proxy for inorganic particles found in surface or ocean waters. In addition to the binary system of actinide/silica, the ternary system actinide/ organic colloid/ silica were also carried out to determine the affect of the organic colloid has on particle association. In particular, extracellular polymeric substances (EPS) extracted from laboratory grown bacteria and phytoplankton cultures were utilized as they too are ubiquitous in aquatic systems and have shown to strongly complex actinide ions, with EPS involved in oceanic scavenging of Th, as well as immobilization/mobilization of Pu in contaminated areas on land.

Roberts, Kimberly Ann

2008-05-01T23:59:59.000Z

456

Comparison of laser-based mitigation of fused silica surface damage using mid- versus far-infrared lasers  

SciTech Connect

Laser induced growth of optical damage can limit component lifetime and therefore operating costs of large-aperture fusion-class laser systems. While far-infrared (IR) lasers have been used previously to treat laser damage on fused silica optics and render it benign, little is known about the effectiveness of less-absorbing mid-IR lasers for this purpose. In this study, they quantitatively compare the effectiveness and efficiency of mid-IR (4.6 {micro}m) versus far-IR (10.6 {micro}m) lasers in mitigating damage growth on fused silica surfaces. The non-linear volumetric heating due to mid-IR laser absorption is analyzed by solving the heat equation numerically, taking into account the temperature-dependent absorption coefficient {alpha}(T) at {lambda} = 4.6 {micro}m, while far-IR laser heating is well-described by a linear analytic approximation to the laser-driven temperature rise. In both cases, the predicted results agree well with surface temperature measurements based on infrared radiometry, as well as sub-surface fictive temperature measurements based on confocal Raman microscopy. Damage mitigation efficiency is assessed using a figure of merit (FOM) relating the crack healing depth to laser power required, under minimally-ablative conditions. Based on their FOM, they show that for cracks up to at least 500 {micro}m in depth, mitigation with a 4.6 {micro}m mid-IR laser is more efficient than mitigation with a 10.6 {micro}m far-IR laser. This conclusion is corroborated by direct application of each laser system to the mitigation of pulsed laser-induced damage possessing fractures up to 225 {micro}m in depth.

Yang, S T; Matthews, M J; Elhadj, S; Cooke, D; Guss, G M; Draggoo, V G; Wegner, P J

2009-12-16T23:59:59.000Z

457

A density functional theory study of the oxidation of methanol to formaldehyde over vanadia supported on silica, titania, and zirconia  

DOE Green Energy (OSTI)

Density functional theory was used to investigate the mechanism and kinetics of methanol oxidation to formaldehyde over vanadia supported on silica, titania, and zirconia. The catalytically active site was modeled as an isolated VO{sub 4} unit attached to the support. The calculated geometry and vibrational frequencies of the active site are in good agreement with experimental measurements both for model compounds and oxide-supported vanadia. Methanol adsorption is found to occur preferentially with the rupture of a V-O-M bond (M = Si, Ti, Zr) and with preferential attachment of a methoxy group to V. The vibrational frequencies of the methoxy group are in good agreement with those observed experimentally as are the calculated isobars. The formation of formaldehyde is assumed to occur via the transfer of an H atom of a methoxy group to the O atom of the V=O group. The activation energy for this process is found to be in the range of 199-214 kJ/mol and apparent activation energies for the overall oxidation of methanol to formaldehyde are predicted to lie in the range of 112-123 kJ/mol, which is significantly higher than that found experimentally. Moreover, the predicted turnover frequency (TOF) for methanol oxidation is found to be essentially independent of support composition, whereas experiments show that the TOF is 10{sup 3} greater for titania- and zirconia-supported vanadia than for silica-supported vanadia. Based on these findings, it is proposed that the formation of formaldehyde from methoxy groups may require pairs of adjacent VO{sub 4} groups or V{sub 2}O{sub 7} dimer structures.

Khaliullin, Rustam Z.; Bell, Alexis T.

2002-09-05T23:59:59.000Z

458

Monitoring Nanomaterials in Situ Elaboration, Structure, Morphology ...  

Science Conference Proceedings (OSTI)

In-Situ Neutron Diffraction and Crystal Plasticity Modeling of a-Uranium · In-Situ Studies of the ... Thermal Residual Stresses and Strains in Depleted Uranium.

459

Optical Nanomaterials for Photonics/Biophotonics  

Science Conference Proceedings (OSTI)

Applications of optical nanoparticles in telecommunications, photodetectors, LED , etc. - Fluorescent Imaging using optical nanolabels (including multiphoton ...

460

Novel Functionalized Nanomaterials for Organic Decontamination  

Science Conference Proceedings (OSTI)

... oxide (TiO2)-graphene-rhamnolipid for decontamination of organics (methyl orange, phenol and diesel) from water. The results show the advantage of organic ...

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461

Nanomaterials/Nanotechnology: Nanoelectronics to improve ...  

Science Conference Proceedings (OSTI)

... History Projections ... This energy demand will continue to grow not only because ... Energy supplies are growing scarcer, energy demands are growing ...

2011-08-02T23:59:59.000Z

462

Using CFN Facilities | Center for Functional Nanomaterials  

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

Using CFN Facilities Using CFN Facilities CFN facilities are available free of charge to scientists from universities, industry, and national laboratories worldwide, for non-proprietary nanoscience research projects. Access to the facilities is granted to external users through a peer-reviewed proposal system. Proposals are submitted electronically and reviewed and rated by an external Proposal Review Panel. Proposals must include the specific equipment requested, the scientific impact of the research project, and a description of the research to be conducted at the CFN. For an accepted proposal, the actual schedule for work at the CFN is jointly made by the leader(s) of the requested facility (or facilities), and the proposal's principal investigator. User Registration All researchers coming to the CFN to work at a facility must have an active

463

Electron Microscopy | Center for Functional Nanomaterials  

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

Electron Microscopy Facility Electron Microscopy Facility Electron Microscopy This facility consists of four top-of-the line transmission electron microscopes, two of which are highly specialized instruments capable of extreme levels of resolution, achieved through spherical aberration correction. The facility is also equipped with extensive sample-preparation capabilities. The scientific interests of the staff focus on understanding the microscopic origin of the physical and chemical behavior of materials, with specific emphasis on in-situ studies of materials in native, functional environments. Capabilities Atomic-resolution imaging of internal materials structure with scanning transmission and transmission electron microscopy Spectroscopic characterization with energy dispersive x-ray

464

BNL | Center for Functional Nanomaterials (CFN)  

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

FEI Titan 80-300 FEI Titan 80-300 A dedicated Environmental Transmission Electron Microscope (E-TEM) Contact: Eric Stach This instrument is the first 80-300kV field-emission environmental transmission electron microscope to be installed in the US with an objective-lens aberration corrector. It has a spatial resolution of 0.08nm in the high-resolution phase contrast mode, and is capable of achieving this resolution at unusually high pressures due to the differential pumping apertures and custom pumping arrangement that is incorporated with the system. The maximum gas pressure for the environmental-cell is about 20mbar for N2, with other maximum pressures dependent on the atomic weight of the gas. As a result, this instrument is uniquely well-suited to imaging the fundamental mechanisms of catalysis and catalyzed nanostructure growth. The