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1

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

SciTech Connect (OSTI)

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

Characterizing Surface Acidic Sites in Mesoporous-Silica-Supported...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Surface Acidic Sites in Mesoporous-Silica-Supported Tungsten Oxide Catalysts Using Solid State NMR and Quantum Characterizing Surface Acidic Sites in Mesoporous-Silica-Supported...

3

Cellular membrane trafficking of mesoporous silica nanoparticles  

SciTech Connect (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

Sample Desorption/Onization From Mesoporous Silica  

DOE Patents [OSTI]

Mesoporous silica is shown to be a sample holder for laser desorption/ionization of mass spectrometry. Supported mesoporous silica was prepared by coating an ethanolic silicate solution having a removable surfactant onto a substrate to produce a self-assembled, ordered, nanocomposite silica thin film. The surfactant was chosen to provide a desired pore size between about 1 nanometer diameter and 50 nanometers diameter. Removal of the surfactant resulted in a mesoporous silica thin film on the substrate. Samples having a molecular weight below 1000, such as C.sub.60 and tryptophan, were adsorbed onto and into the mesoporous silica thin film sample holder and analyzed using laser desorption/ionization mass spectrometry.

Iyer, Srinivas (Los Alamos, NM); Dattelbaum, Andrew M. (Los Alamos, NM)

2005-10-25T23:59:59.000Z

5

Multitasking mesoporous nanomaterials for biorefinery applications  

SciTech Connect (OSTI)

Mesoporous silica nanoparticles (MSNs) have attracted great interest for last two decades due to their unique and advantageous structural properties, such as high surface area, pore volume, stable mesostructure, tunable pore size and controllable particle morphology. The robust silica framework provides sites for organic modifications, making MSNs ideal platforms for adsorbents and supported organocatalysts. In addition, the pores of MSNs provide cavities/ channels for incorporation of metal and metal oxide nanoparticle catalysts. These supported metal nanoparticle catalysts benefit from confined local environments to enhance their activity and selectivity for various reactions. Biomass is considered as a sustainable feedstock with potential to replace diminishing fossil fuels for the production of biofuels. Among several strategies, one of the promising methods of biofuel production from biomass is to reduce the oxygen content of the feedstock in order to improve the energy density. This can be achieved by creating C-C bonds between biomass derived intermediates to increase the molecular weight of the final hydrocarbon molecules. In this context, pore size and organic functionality of MSNs are varied to obtain the ideal catalyst for a C-C bond forming reaction: the aldol condensation. The mechanistic aspects of this reaction in supported heterogeneous catalysts are explored. The modification of supported organocatalyst and the effect of solvent on the reaction are rationalized. The significance of two functional surfaces of MSNs is exploited by enzyme immobilization on the external surface and organo catalyst functionalization on the internal surface. Using this bifunctional catalyst, the tandem conversion of small chain alcohols into longer chain hydrocarbon molecules is demonstrated. The ability to incorporate metal and metal oxide nanoparticles in the pores and subsequent functionalization led to develop organic modified magnetic MSNs (OM-MSNs) for applications in microalgae biorefinery. Two different integrated biorefinery systems are highlighted. (i) OM-MSNs are used to harvest microalgae and selectively sequester free fatty acids (FFAs). (ii) OM-MSNs are shown to selectively sequester FFAs and convert them into diesel-range liquid hydrocarbon fuels. A similar MSN supported metal nanoparticle catalyst is demonstrated to transform FFAs into green diesel with even greater activity and selectivity. 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

6

Biological Applications and Transmission Electron Microscopy Investigations of Mesoporous Silica Nanoparticles  

SciTech Connect (OSTI)

The research presented and discussed within involves the development of novel biological applications of mesoporous silica nanoparticles (MSN) and an investigation of mesoporous material by transmission electron microscopy (TEM). Mesoporous silica nanoparticles organically functionalized shown to undergo endocytosis in cancer cells and drug release from the pores was controlled intracellularly and intercellularly. Transmission electron microscopy investigations demonstrated the variety of morphologies produced in this field of mesoporous silica nanomaterial synthesis. A series of room-temperature ionic liquid (RTIL) containing mesoporous silica nanoparticle (MSN) materials with various particle morphologies, including spheres, ellipsoids, rods, and tubes, were synthesized. By changing the RTIL template, the pore morphology was tuned from the MCM-41 type of hexagonal mesopores to rotational moire type of helical channels, and to wormhole-like porous structures. These materials were used as controlled release delivery nanodevices to deliver antibacterial ionic liquids against Escherichia coli K12. The involvement of a specific organosiloxane function group, covalently attached to the exterior of fluorescein doped mesoporous silica nanoparticles (FITC-MSN), on the degree and kinetics of endocytosis in cancer and plant cells was investigated. The kinetics of endocystosis of TEG coated FITC-MSN is significantly quicker than FITC-MSN as determined by flow cytometry experiments. The fluorescence confocal microscopy investigation showed the endocytosis of TEG coated-FITC MSN triethylene glycol grafted fluorescein doped MSN (TEG coated-FITC MSN) into both KeLa cells and Tobacco root protoplasts. Once the synthesis of a controlled-release delivery system based on MCM-41-type mesoporous silica nanorods capped by disulfide bonds with superparamagnetic iron oxide nanoparticles was completed. The material was characterized by general methods and the dosage and kinetics of the antioxidant dependent release was measured. Finally, the biological interaction of the material was determined along with TEM measurements. An electron investigation proved that the pore openings of the MSN were indeed blocked by the Fe{sub 3}O{sub 4} nanoparticles. The biological interaction investigation demonstrated Fe{sub 3}O{sub 4}-capped MSN endocytosis into HeLa cells. Not only does the material enter the cells through endocytosis, but it seems that fluorescein was released from the pores most probably caused by disulfide bond reducing molecules, antioxidants. In addition to endocytosis and release, the Fe{sub 3}O{sub 4}-capped MSN propelled the cells across a cuvette upon induction of a magnet force. Finally, an important aspect of materials characterization is transmission electron microscopy. A TEM investigation demonstrated that incorporating different functional groups during the synthesis (co-condensation) changed the particle and pore morphologies.

Brian G. Trewyn

2006-05-01T23:59:59.000Z

7

Carbon nanomaterials in silica aerogel matrices  

SciTech Connect (OSTI)

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

8

Synthesis of highly ordered mesoporous silica materials using sodium silicate and amphiphilic block copolymers  

E-Print Network [OSTI]

Synthesis of highly ordered mesoporous silica materials using sodium silicate and amphiphilic block) structures, using sodium silicate as the silica source and amphiphilic block copolymers as the structure of mesoporous silica material using nonionic surfac- tant and sodium silicate in the pH range 3­10.5. However

Kim, Ji Man

9

Fluorescent Functionalized Mesoporous Silica for Radioactive Material Extraction  

SciTech Connect (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

10

Preparation of Mesoporous Silica Templated Metal Nanowire Films on Foamed Nickel Substrates  

SciTech Connect (OSTI)

A method has been developed for the formation of high surface area nanowire films on planar and three-dimensional metal electrodes. These nanowire films are formed via electrodeposition into a mesoporous silica film. The mesoporous silica films are formed by a sol-gel process using Pluronic tri-block copolymers to template mesopore formation on both planar and three-dimensional metal electrodes. Surface area increases of up to 120-fold have been observed in electrodes containing a templated film when compared to the same types of electrodes without the templated film.

Campbell, Roger [University of Alabama, Tuscaloosa; Kenik, Edward A [ORNL; Bakker, Martin [University of Alabama, Tuscaloosa; Havrilla, George [Los Alamos National Laboratory (LANL); Montoya, Velma [Los Alamos National Laboratory (LANL); Shamsuzzoha, Mohammed [University of Alabama, Tuscaloosa

2006-01-01T23:59:59.000Z

11

Magnetic properties of mesoporous cobalt-silica-alumina ternary mixed oxides  

SciTech Connect (OSTI)

Mesoporous cobalt-silica-alumina mixed oxides with variable cobalt content have been synthesized through slow evaporation method by using Pluronic F127 non-ionic surfactant as template. N{sub 2} sorption analysis of the template-free mixed oxide samples revealed that these mesoporous materials have high BET surface areas together with large mesopores. Powder XRD, TEM, EDS, FT IR and EPR spectroscopic analysis have been employed to understand the nature of the mesophases, bonding and composition of the materials. Low temperature magnetic measurements of these mixed oxide materials show the presence of ferromagnetic correlation at elevated temperature though at low temperature paramagnetic to ferrimagnetic transition is observed. Highlights: Black-Right-Pointing-Pointer Mesoporous cobalt-silica-alumina ternary mixed oxides. Black-Right-Pointing-Pointer High surface area and mesoporosity in magnetic materials. Black-Right-Pointing-Pointer Ferromagnetic correlation at elevated temperature. Black-Right-Pointing-Pointer Low temperature paramagnetic to ferrimagnetic transition.

Pal, Nabanita [Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032 (India)] [Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032 (India); Seikh, Md. Motin [Department of Chemistry, Visva-Bharati University, Santiniketan, West Bengal (India)] [Department of Chemistry, Visva-Bharati University, Santiniketan, West Bengal (India); Bhaumik, Asim, E-mail: msab@iacs.res.in [Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032 (India)] [Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032 (India)

2013-02-15T23:59:59.000Z

12

Development of 3-D magnetic nano-arrays by electrodeposition into mesoporous silica.  

SciTech Connect (OSTI)

The development of periodic nanostructures fabricated by self-assembly of surfactants and block co-polymers has opened up the possibility of generating periodic magnetic nanostructures of types not accessible by self-assembly of nano-particles. The fabrication of mesoporous silica thin films around self-assembled block co-polymers is well established. Common structures for such films are SBA-15 which consists of hexagonal arrays of cylindrical pores and SBA-16 which has face centered arrays of spherical voids. These pores are connected by 1-2 nm thick flaws in the continuous silica phase producing an effectively continuous porous phase. After removal of the block co-polymer template, electrodeposition into the mesoporous silica thin films produces arrays of 5-10 nm diameter nano-wires and nano-particles. We have demonstrated that such materials can be fabricated on a wide range of metal substrates. Characterization by Scanning Electron Microscopies shows that the mesoporous silica is well ordered over micron scale areas. Grazing Incidence Small Angle X-ray Scattering (GISAXS) studies shows diffraction spots, consistent with the entire film being well ordered. GISAXS also shows that the mesoporous silica films survive removal of the template and electrodeposition of nickel and cobalt into the mesoporous silica films. Such films are of interest for their magnetic properties, as the nanophase and scale can be independently varied. Further, the presence of nanowires inside an insulator suggests that these films might also be of interest as the current confining element for Confined Current Path-Current Perpendicular to Plane GMR sensors.

Campbell, R.; Manning, J.; Bakker, M.G.; Li, X.; Lee, D.R.; Wang, J.; X-Ray Science Division; Univ. of Alabama

2006-01-01T23:59:59.000Z

13

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

E-Print Network [OSTI]

EPR study of the adsorption of dioxin vapours onto microporous carbons and mesoporous silica M 31 October 2010 Keywords: EPR AC MTS Surface characterization Dioxin a b s t r a c t Computer aided with a nitroxide radical (TCDD-T) was employed to investigate the adsorption of dioxin vapours onto two carbons

Turro, Nicholas J.

14

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]

Scheme 2) and pyrrole hydrogenation (Scheme 3). Synthesis ofSynthesis of One Nanometer Rh and Pt Particles Supported on Mesoporous Silica: Catalytic Activity for Ethylene and Pyrrole

Huang, Wenyu

2009-01-01T23:59:59.000Z

15

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

SciTech Connect (OSTI)

In this work, we describe the controlled synthesis of novel heterogeneous nanostructures comprised of mesoporous silica-coated gold nanorods (MSGNRs) in the form of core–shell nanolollipops and nanodumb-bells, using a seed-mediated sol–gel method. Although MSGNR core–shell (?-MSGNR) structures have been reported previously by us and others, we herein discuss the first ever fabrication of MSGNR nanolollipops (?-MSGNR) and nanodumb-bells (?-MSGNR), achieved by simply controlling the aging time of gold nanorods (GNRs), the residual cetyltrimethylammonium bromide (CTAB) coating of GNRs, and the addition of dimethyl formamide during incubation, centrifugation, and sonication, respectively. Transmission electron microscopy revealed two bare GNR isoforms, with aspect ratios of approximately 4 and 6, while scanning electron microscopy was used to further elucidate the morphology of ?-MSGNR and ?-MSGNR heterostructures. In agreement with the smaller dielectric constants afforded by incomplete silica encasement, spectroscopic studies of ?-MSGNR and ?-MSGNR, surface plasmon resonance (SPR) bands revealed 20-40 nm blue shifts relative to the SPR of ?-MSGNR. On the basis of the attributes and applications of more conventional ?-MSGNRs, ?-MSGNRs and ?-MSGNRs are anticipated to provide most of the utility of ?-MSGNRs, but with the additional functionalities that accompany their incorporation of both bare gold and mesoporous silica encased tips; with significant/unique implications for biomedical and catalytic applications.

Huang, Ching-Mao [Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, 35 Keyan Road, Zhunan Town, Miaoli 35053, Taiwan (China); Material and Chemical Laboratories, Industrial Technology Research Institute, Hsinchu 30011, Taiwan (China); Chung, Ming-Fang; Lo, Leu-Wei, E-mail: lwlo@nhri.org.tw [Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, 35 Keyan Road, Zhunan Town, Miaoli 35053, Taiwan (China); Souris, Jeffrey S. [Department of Radiology, The University of Chicago, Chicago, Illinois 60637 (United States)

2014-11-01T23:59:59.000Z

16

Magnetic properties of magnetite nanoparticles coated with mesoporous silica by sonochemical method  

SciTech Connect (OSTI)

Highlights: Black-Right-Pointing-Pointer MCM-41-coating of magnetite nanoparticles performed under ultrasonic irradiation. Black-Right-Pointing-Pointer Ultrasonic irradiation accelerates the formation of the MCM-41 framework. Black-Right-Pointing-Pointer The hysteretic response to an applied field was investigated applying FORC diagram. Black-Right-Pointing-Pointer The average coercive field of the Fe{sub 3}O{sub 4} nanoparticles increased after coating. -- Abstract: In this paper we present the magnetic properties of mesoporous silica-coated Fe{sub 3}O{sub 4} nanoparticles. The coating of magnetite nanoparticles with mesoporous silica shell was performed under ultrasonic irradiation. The obtained mesoporous silica-coated magnetite nanoparticles were characterized by powder X-ray diffraction, focused ion beam-scanning electron microscopy, nitrogen adsorption-desorption isotherms and vibrating sample magnetometer. The hysteretic behavior was studied using first-order reversal curves diagrams. The X-ray diffraction result indicates that the extreme chemical and physical conditions created by acoustic cavitations have an insignificant effect on crystallographic structural characteristic of magnetite nanoparticles. Changes in the coercivity distributions of the magnetite nanoparticles were observed on the first-order reversal curves diagrams for the samples with coated particles compared with the samples containing uncoated particles of magnetite. The coated particles show an increased most probable coercivity of about 20% compared with the uncoated particles which can be associated with an increased anisotropy due to coating even if the interaction field distribution measured on the diagrams are virtually identical for coated/uncoated samples.

Ursachi, Irina [Department of Physics and CARPATH Center, 'Alexandru Ioan Cuza' University of Iasi, 11 Carol I Blvd., 700506 Iasi (Romania)] [Department of Physics and CARPATH Center, 'Alexandru Ioan Cuza' University of Iasi, 11 Carol I Blvd., 700506 Iasi (Romania); Vasile, Aurelia [Department of Chemistry, 'Alexandru Ioan Cuza' University of Iasi, 11 Carol I Blvd., 700506 Iasi (Romania)] [Department of Chemistry, 'Alexandru Ioan Cuza' University of Iasi, 11 Carol I Blvd., 700506 Iasi (Romania); Chiriac, Horia [National Institute of Research and Development for Technical Physics, 47 Mangeron Blvd., 700050 Iasi (Romania)] [National Institute of Research and Development for Technical Physics, 47 Mangeron Blvd., 700050 Iasi (Romania); Postolache, Petronel [Department of Physics and CARPATH Center, 'Alexandru Ioan Cuza' University of Iasi, 11 Carol I Blvd., 700506 Iasi (Romania)] [Department of Physics and CARPATH Center, 'Alexandru Ioan Cuza' University of Iasi, 11 Carol I Blvd., 700506 Iasi (Romania); Stancu, Alexandru, E-mail: alstancu@uaic.ro [Department of Physics and CARPATH Center, 'Alexandru Ioan Cuza' University of Iasi, 11 Carol I Blvd., 700506 Iasi (Romania)] [Department of Physics and CARPATH Center, 'Alexandru Ioan Cuza' University of Iasi, 11 Carol I Blvd., 700506 Iasi (Romania)

2011-12-15T23:59:59.000Z

17

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

E-Print Network [OSTI]

Hydrothermal Growth of Mesoporous SBA-15 Silica in the Presence of PVP-Stabilized Pt Nanoparticles hydrothermal synthesis. Characterization of the Pt/SBA-15 catalysts suggests that Pt particles are located are responsible for ethane decomposition to surface carbon. The ability to design catalytic structures

Yang, Peidong

18

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

E-Print Network [OSTI]

method at the dipping rate of 2 cm/min. After the coating, the piece was dried in air at 80 o C overnight is coated on the cobalt thin film deposited by sputtering. From these investigations, it is concluded silica film should have mesopores which run through the film from the substrate to the surface. Even

Maruyama, Shigeo

19

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

SciTech Connect (OSTI)

Molecular Dynamics (MD) simulations were carried out to determine the self-diffusivitiy, D{sub i,self}, the Maxwell–Stefan diffusivity, Ð{sub i}, and the Fick diffusivity, D{sub i}, for methane (C1), ethane (C2), propane (C3), n-butane (nC4), n-pentane (nC5), n-hexane (nC6), n-heptane (nC7), and cyclohexane (cC6) in cylindrical silica mesopores for a range of pore concentrations. The MD simulations show that zero-loading diffusivity Ð{sub i}(0) is consistently lower, by up to a factor of 20, than the values anticipated by the classical Knudsen formula. The concentration dependence of the Fick diffusivity, D{sub i} is found to be unusually complex, and displays a strong minimum in some cases; this characteristic can be traced to molecular clustering.

Krishna, Rajamani; van Baten, Jasper M

2011-01-01T23:59:59.000Z

20

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

SciTech Connect (OSTI)

In steam reforming reactions (SRRs) of alkanes and alcohols to produce H{sub 2}, noble metals such as platinum (Pt) and palladium (Pd) are extensively used as catalyst. These metals are expensive; so, to reduce noble-metal loading, bi-metallic nanocatalysts containing non-noble metals in MCM-41 (Mobil Composition of Material No. 41, a mesoporous material) as a support material with high-surface area were synthesized using one-pot hydrothermal procedure with a surfactant such as cetyltrimethylammonium bromide (CTAB) as a template. Bi-metallic nanocatalysts of Pd-Ni and Pd-Co with varying metal loadings in MCM-41 were characterized by x-ray diffraction (XRD), N{sub 2} adsorption, and Transmission electron microscopy (TEM) techniques. The BET surface area of MCM-41 (~1000 m{sup 2}/g) containing metal nanoparticles decreases with the increase in metal loading. The FTIR studies confirm strong interaction between Si-O-M (M = Pd, Ni, Co) units and successful inclusion of metal into the mesoporous silica matrix. The catalyst activities were examined in steam reforming of methanol (SRM) reactions to produce hydrogen. Reference tests using catalysts containing individual metals (Pd, Ni and Co) were also performed to investigate the effect of the bimetallic system on the catalytic behavior in the SRM reactions. The bimetallic system remarkably improves the hydrogen selectivity, methanol conversion and stability of the catalyst. The results are consistent with a synergistic behavior for the Pd-Ni-bimetallic system. The performance, durability and thermal stability of the Pd-Ni/MCM-41 and Pd-Co/MCM-41 suggest that these materials may be promising catalysts for hydrogen production from biofuels. A part of this work for synthesis and characterization of Pd-Ni-MCM-41 and its activity for SRM reactions has been published (“Development of Mesoporous Silica Encapsulated Pd-Ni Nanocatalyst for Hydrogen Production” in “Production and Purification of Ultraclean Transportation Fuels”; Hu, Y., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2011.)

Kuila, Debasish; Ilias, Shamsuddin

2013-02-13T23:59:59.000Z

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

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

SciTech Connect (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

22

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

SciTech Connect (OSTI)

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

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

2013-10-15T23:59:59.000Z

23

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

SciTech Connect (OSTI)

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

Nakamura, Ryuhei; Frei, Heinz

2006-07-10T23:59:59.000Z

24

Nano-Structured Mesoporous Silica Wires with Intra-Wire Lamellae via Evaporation-Induced Self-Assembly in Space-Confined Channels  

SciTech Connect (OSTI)

Evaporation-induced self-assembly (EISA) of silica sol-gel ethanol-water solution mixtures with block-copolymer were studied inside uniform micro/nano channels. Nano-structured mesoporous silica wires, with various intra-wire self-assembly structures including lamellae, were prepared via EISA process but in space-confined channels with the diameter ranging from 50 nm to 200 nm. Membranes made of anodized aluminum oxide (AAO) and track-etched polycarbonate (EPC) were utilized as the arrays of space-confined channels (i.e., 50, 100, and 200-nm EPC and 200-nm AAO) for infiltration and drying of mixture solutions; these substrate membranes were submerged in mixture solutions consisting of a silica precursor, a structure-directing agent, ethanol, and water. After the substrate channels were filled with the solution under vacuum impregnation, the membrane was removed from the solution and dried in air. The silica precursor used was tetra-ethyl othosilicate (TEOS), and the structure-directing agent employed was triblock copolymer Pluronic-123 (P123). It was found that the formation of the mesoporous nanostructures in silica wires within uniform channels were significantly affected by the synthesis conditions including (1) pre-assemble TEOS aging time, (2) the evaporation rate during the vacuum impregnation, and (3) the air-dry temperature. The obtained intra-wire structures, including 2D-hexagonal rods and lamellae, were studied by scanning transmission electron microscopy (STEM). A steric hindrance effect seems to explain well the observed polymer-silica mesophase formation tailored by TEOS aging time. The evaporation effect, air-drying effect, and AAO-vs-EPC substrate effect on the mesoporous structure of the formed silica wires were also presented and discussed.

Hu, Michael Z. [ORNL; Shi, Donglu [University of Cincinnati; Blom, Douglas Allen [ORNL

2014-01-01T23:59:59.000Z

25

Sol-Gel Mesoporous Silica Aerogels and Bio Hybrids for Functional Applications.  

E-Print Network [OSTI]

??The thesis covers a systematic investigation on the synthesis of silica aerogels and microspheres with tailored porosity, at ambient conditions by varying the experimental parameters… (more)

Smitha, Sasidharan

2009-01-01T23:59:59.000Z

26

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

SciTech Connect (OSTI)

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

Frei, Heinz; Han, Hongxian; Frei, Heinz

2008-06-04T23:59:59.000Z

27

Thermal Conductivity of Ordered Mesoporous Nanocrystalline Silicon Thin Films Made from Magnesium Reduction of Polymer-  

E-Print Network [OSTI]

Thermal Conductivity of Ordered Mesoporous Nanocrystalline Silicon Thin Films Made from Magnesium-assembly of mesoporous silica followed by magnesium reduction. The periodic ordering of pores in mesoporous silicon

Pilon, Laurent

28

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

SciTech Connect (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

29

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

E-Print Network [OSTI]

Ti-MCM-41 silica in acetonitrile solution affords binucleardirectly dissolved in acetonitrile (50 mL) in a Schlenk tubeupon dissolving CoCl 2 in acetonitrile is believed to be the

Han, Hongxian; Frei, Heinz

2008-01-01T23:59:59.000Z

30

In-situ Spectroscopy of Water Oxidation at Ir Oxide Nanocluster Drivenby Visible TiOCr Charge-Transfer Chromophore in Mesoporous Silica  

SciTech Connect (OSTI)

An all-inorganic photocatalytic unit consisting of a binuclear TiOCr charge-transfer chromophore coupled to an Ir oxide nanocluster has been assembled on the pore surface of mesoporous silica AlMCM-41. In situ FT-Raman and EPR spectroscopy of an aqueous suspension of the resulting IrxOy-TiCr-AlMCM-41 powder reveal the formation of superoxide species when exciting the Ti(IV)OCr(III) --> Ti(III)OCr(IV) metal-to-metal charge-transfer chromophore with visible light. Use of H218O confirms that the superoxide species originates from oxidation of water. Photolysis in the absence of persulfate acceptor leads to accumulation of Ti(III) instead. The results are explained by photocatalytic oxidation of water at Ir oxide nanoclusters followed by trapping of the evolving O2 by transient Ti(III) centers to yield superoxide. Given the flexibility to select donor metals with appropriate redox potential, photocatalytic units consisting of a binuclear charge-transfer chromophore coupled to a water oxidation catalyst shown here constitute a step towards thermodynamically efficient visible light water oxidation units.

Frei, Heinz; Han, Hongxian; Frei, Heinz

2008-06-03T23:59:59.000Z

31

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

SciTech Connect (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

32

Kinetics of oxidation of an organic amine with a Cr(V) salen complex in homogeneous aqueous solution and on the surface of mesoporous silica  

SciTech Connect (OSTI)

A comparative study of catalytic activity under homogeneous and heterogeneous conditions was carried out using the (salen)Cr{sup III}-catalyzed oxidation of tetramethylbenzidine (TMB) with iodosobenzene as a model reaction. Amine-functionalized mesoporous silica nanoparticles (MSN) were synthesized in a co-condensation reaction and functionalized with salen via a covalent Si-C bond. A Cr(III) complex of this supported ligand, MSN-(salen)Cr{sup III}, was prepared and characterized. Data from powder XRD, BET isotherms and BJH pore size distribution all showed that MSN-(salen)Cr{sup III} still had the typical MSN high surface area, narrow pore size distribution, and ordered hexagonal pore structure, which were further confirmed by transmission electron microscopy (TEM) images. {sup 13}C and {sup 29}Si solid-state NMR data provided structural information about the catalyst and verified successful functionalization of the salen ligand and coordination to Cr(III). No unreacted salen or Cr(III) were observed. The loadings of salen and salen-Cr{sup III} complex were determined via TGA and EDX, respectively. Both measurements indicated that approximately 0.5 mmol/g of catalyst was loaded on the surface of MSN. The oxidation of TMB with iodosobenzene using MSN-(salen)Cr{sup III} as a heterogeneous catalyst exhibited both similarities and differences with the analogous homogeneous reaction using (salen)Cr{sup III}(H{sub 2}O){sup +} as a catalyst in aqueous acetonitrile. In the presence of 0.10 M HClO{sub 4}, the two catalytic reactions proceeded at similar rates and generated the doubly oxidized product TMB{sup 2+}. In the absence of acid, the radical cation TMB{sup +} was produced. The kinetics of the heterogeneous reaction in the absence of added acid responded to concentrations of all three reagents, i.e. (salen)Cr{sup III}, TMB, and PhIO.

Szajna-Fuller, Ewa; Huang, Yulin; Rapp, Jennifer L.; Chaka, Gezhegn; Lin, Victor S.Y.; Pruski, Marek; Bakac, Andreja

2009-03-09T23:59:59.000Z

33

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

34

Preparation of Micrometer-to Sub-micrometer-Sized Nanostructured Silica Particles Using High-Energy Ball Milling  

E-Print Network [OSTI]

, mesoporous silica synthesized in the form of thin films,3 aerogels,4 and particles are the most cited

Mitchell, Brian S.

35

Novel nanomaterials based on 5,10,15,20-tetrakis(3,4-dimethoxyphenyl)-21H,23H-porphyrin entrapped in silica matrices  

SciTech Connect (OSTI)

The present study is dealing with the obtaining of transparent hybrid silica materials encapsulating 5,10,15,20-tetrakis(3,4-dimethoxyphenyl)-21H,23H-porphyrin designated for advanced optoelectronic devices. The porphyrin was synthesized by three methods: an Adler-type reaction between pyrrole and 3,4-dimethoxybenzaldehyde in propionic acid medium; by Lindsey condensation of pyrrole with 3,4-dimethoxybenzaldehyde in the presence of BF{sub 3}.OEt{sub 2} and by a multicomponent reaction by simultaneously using of pyrrole and two different aldehydes: 3,4-dimethoxybenzaldehyde and 3-hydroxybenzaldehyde. The 3,4-dimethoxyphenyl substituted porphyrin was characterized by HPLC, TLC, UV-vis, FT-IR, {sup 1}H NMR and {sup 13}C NMR analysis. Excitation and emission spectra were also discussed in terms of pH conditions. The hybrid materials, consisting in the porphyrin encapsulated in silica matrices, have been prepared successfully via the two steps acid-base catalyzed hydrolysis and condensation of tetraethylorthosilicate using different approaches of the sol-gel process: in situ, by impregnation and by sonication. The synthetic conditions and the compositions were monitored and characterized by using spectroscopic methods such as FT-IR, fluorescence and UV-vis. Atomic force microscopy (AFM) has been applied to observe the columnar or pyramidal nanostructures which are formed by the immobilization of porphyrin on the silica matrices.

Fagadar-Cosma, Eugenia, E-mail: efagadar@yahoo.com [Institute of Chemistry Timisoara of Romanian Academy, M. Viteazu Ave, No. 24, 300223 Timisoara (Romania)] [Institute of Chemistry Timisoara of Romanian Academy, M. Viteazu Ave, No. 24, 300223 Timisoara (Romania); Enache, Corina [Institute of Chemistry Timisoara of Romanian Academy, M. Viteazu Ave, No. 24, 300223 Timisoara (Romania)] [Institute of Chemistry Timisoara of Romanian Academy, M. Viteazu Ave, No. 24, 300223 Timisoara (Romania); Vlascici, Dana [West University of Timisoara, Pestalozzi Street, No. 16, 300115 Timisoara (Romania)] [West University of Timisoara, Pestalozzi Street, No. 16, 300115 Timisoara (Romania); Fagadar-Cosma, Gheorghe ['Politehnica' University, T. Lalescu Street, No. 2, 300223 Timisoara (Romania)] ['Politehnica' University, T. Lalescu Street, No. 2, 300223 Timisoara (Romania); Vasile, Mihaela [National Institute for Research and Development in Electrochemistry and Condensed Matter, P. Andronescu Street, No. 1, 300224 Timisoara (Romania)] [National Institute for Research and Development in Electrochemistry and Condensed Matter, P. Andronescu Street, No. 1, 300224 Timisoara (Romania); Bazylak, Grzegorz [Collegium Medicum, Nicolaus Copernicus University, Department of Pharmaco-Bromatology and Molecular Nutrition, Jagiellonska, No. 13, PL-85-067 Bydgoszcz (Poland)] [Collegium Medicum, Nicolaus Copernicus University, Department of Pharmaco-Bromatology and Molecular Nutrition, Jagiellonska, No. 13, PL-85-067 Bydgoszcz (Poland)

2009-12-15T23:59:59.000Z

36

Sustainable Nanomaterials Industry Perspective  

Broader source: Energy.gov [DOE]

Presentation for the Sustainable Nanomaterials Workshop by MeadWestvaco Corporation held on June 26, 2012

37

Influence of the pressure on the properties of chromatographic columns I. Measurement of the compressibility of methanol-water mixtures on a mesoporous silica adsorbent  

SciTech Connect (OSTI)

The compressibilities of aqueous solutions of methanol or acetonitrile containing 0, 20, 40, 60, 80 and 100% (v/v) organic solvent were measured with a dynamic chromatographic method. The elution volumes of thiourea samples (2 {micro} L) in these solutions were measured at different average column pressures, adjusted by placing suitable capillary restrictors on-line, after the detector. The reproducibility of the measurements was better than 0.2%. In the range of average pressures studied (10-350 bar), the maximum change in elution volume of thiourea is 1.3% (in pure water) and 4.0% (in pure methanol). This difference is due to the different compressibilities of these pure solvents. For mixtures, the plots of the elution volume of thiourea versus the pressure are convex downward, which is inconsistent with the opposite curvature predicted by the classical Tait model of liquid compressibility. This difference is explained by the variation of the amount of thiourea adsorbed with the pressure. The deconvolution of the two effects, adsorption of thiourea and solvent compressibility, allows a fair and consistent determination of the compressibilities of the methanol-water mixtures. A column packed with non-porous silica particles was also used to determine the compressibility of methanol-water and acetonitrile-water mixtures. A negative deviation by respect to ideal behavior was observed.

Gritti, Fabrice [University of Tennessee, Knoxville (UTK); Guiochon, Georges A [ORNL

2005-03-01T23:59:59.000Z

38

Influence of the pressure on the properties of chromatographic columns I. Measurement of the compressibility of methanol-water mixtures on a mesoporous silica adsorbent  

SciTech Connect (OSTI)

The compressibilities of aqueous solutions of methanol or acetonitrile containing 0, 20, 40, 60, 80 and 100% (v/v) organic solvent were measured with a dynamic chromatographic method. The elution volumes of thiourea samples (2 {micro} L) in these solutions were measured at different average column pressures, adjusted by placing suitable capillary restrictors on-line, after the detector. The reproducibility of the measurements was better than 0.2%. In the range of average pressures studied (10-350 bar), the maximum change in elution volume of thiourea is 1.3% (in pure water) and 4.0% (in pure methanol). This difference is due to the different compressibilities of these pure solvents. For mixtures, the plots of the elution volume of thiourea versus the pressure are convex downward, which is inconsistent with the opposite curvature predicted by the classical Tait model of liquid compressibility. This difference is explained by the variation of the amount of thiourea adsorbed with the pressure. The deconvolution of the two effects, adsorption of thiourea and solvent compressibility, allows a fair and consistent determination of the compressibilities of the methanol-water mixtures. A column packed with non-porous silica particles was also used to determine the compressibility of methanol-water and acetonitrile-water mixtures. A negative deviation by respect to ideal behavior was observed.

Gritti, Fabrice [University of Tennessee, Knoxville (UTK); Guiochon, Georges A [ORNL

2005-04-01T23:59:59.000Z

39

Mesoporous carbon materials  

DOE Patents [OSTI]

A conductive mesoporous carbon composite comprising conductive carbon nanoparticles contained within a mesoporous carbon matrix, wherein the conductive mesoporous carbon composite possesses at least a portion of mesopores having a pore size of at least 10 nm and up to 50 nm, and wherein the mesopores are either within the mesoporous carbon matrix, or are spacings delineated by surfaces of said conductive carbon nanoparticles when said conductive carbon nanoparticles are fused with each other, or both. Methods for producing the above-described composite, devices incorporating them (e.g., lithium batteries), and methods of using them, are also described.

Dai, Sheng; Fulvio, Pasquale Fernando; Mayes, Richard T.; Wang, Xiqing; Sun, Xiao-Guang; Guo, Bingkun

2014-09-09T23:59:59.000Z

40

Surfactant-Templated Mesoporous Silicate Materials as Sorbents for  

E-Print Network [OSTI]

Surfactant-Templated Mesoporous Silicate Materials as Sorbents for Organic Pollutants in Water H O hexadecyltrimethylammonium bromide(HDTMA)andtetramethyl-orthosilicate(TMOS)orNa- silicate. Products with (as of quartz and amorphous silica. Si dissolution rates for as-synthesized (using Na-silicate) products at pH 7

Illinois at Chicago, University of

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

Mesoporous vanadium pentoxide nanofibers with significantly enhanced Li-ion storage properties by electrospinning  

E-Print Network [OSTI]

.1039/c0ee00313a Mesoporous V2O5 nanofibers were fabricated by a method combining sol­gel processing and de-interca- lation. There are many methods for fabricating nanomaterials, such as hydrothermal the most simple and versatile process for generating nanofibers.10 A variety of simple oxide nanofibers can

Cao, Guozhong

42

Sustainable Nanomaterials Workshop  

Broader source: Energy.gov [DOE]

The Sustainable Nanomaterials Workshop (held in Washington, D.C., on June 26, 2012) gathered stakeholders from industry and academia to discuss the current state of the art for sustainable nanomat...

43

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

SciTech Connect (OSTI)

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

44

Synthesis, characterization, and application of surface-functionalized ordered mesoporous nanoparticles  

SciTech Connect (OSTI)

The dissertation begins with Chapter 1, which is a general introduction of the fundamental synthesis of mesoporous silica materials, the selective functionlization of mesoporous silica materials, and the synthesis of nanostructured porous materials via nanocasting. In Chapter 2, the thermo-responsive polymer coated mesoporous silica nanoparticles (MSN) was synthesized via surface-initated polymerization and exhibited unique partition activities in a biphasic solution with the thermally induced change. In Chapter 3, the monodispersed spherical MSN with different mesoporous structure (MCM-48) was developed and employed as a template for the synthesis of mesoporous carbon nanoparticles (MCN) via nanocasting. MCN was demonstrated for the delivery of membrane impermeable chemical agents inside the cells. The cellular uptake efficiency and biocompabtibility of MCN with human cervical cancer cells were also investigated. In addition to the biocompabtibility of MCN, MCN was demonstrated to support Rh-Mn nanoparticles for catalytic reaction in Chapter 4. Owing to the unique mesoporosity, Rh-Mn nanoparticles can be well distributed inside the mesoporous structure and exhibited interesting catalytic performance on CO hydrogenation. In Chapter 5, the synthesis route of the aforementioned MCM-48 MSN was discussed and investigated in details and other metal oxide nanoparticles were also developed via nanocasting by using MCM-48 MSN as a template. At last, there is a general conclusion summarized in Chapter 6.

Chung, Po-Wen

2009-12-15T23:59:59.000Z

45

July 2013 Most Viewed Documents for Biology And Medicine | OSTI...  

Office of Scientific and Technical Information (OSTI)

1994 NONE (1995) 39 > Defining the Effectiveness of UV Lamps Installed in Circulating Air Ductwork Douglas VanOsdell; Karin Foarde (2002) 32 > Mesoporous Silica Nanomaterials...

46

Organized thiol functional groups in mesoporous core shell colloids  

SciTech Connect (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

47

Center for Functional Nanomaterials  

ScienceCinema (OSTI)

Staff from Brookhaven's new Center for Functional Nanomaterials (CFN) describe how this advanced facility will focus on the development and understanding of nanoscale materials. The CFN provides state-of-the-art capabilities for the fabrication and study of nanoscale materials, with an emphasis on atomic-level tailoring to achieve desired properties and functions. The overarching scientific theme of the CFN is the development and understanding of nanoscale materials that address the Nation's challenges in energy security.

BNL

2009-09-01T23:59:59.000Z

48

Mesoporous carbon materials  

DOE Patents [OSTI]

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

49

Mesoporous carbon materials  

DOE Patents [OSTI]

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 (Knoxville, TN); Wang, Xiqing (Oak Ridge, TN)

2012-02-14T23:59:59.000Z

50

DOI: 10.1002/adma.200701303 Nanolayered Carbon/Silica Superstructures via Organosilane  

E-Print Network [OSTI]

. A main advantage using mesoporous silica is to synthesize carbon/silica composite materials with tunable of amorphous carbon materials after carbonization, and uncontrolled morphologies of composite materials is typically high. However, the composites are not uniform; car- bonization mainly produces amorphous carbon

Zhu, Yuntian T.

51

Noncovalently functionalized graphitic mesoporous carbon as a...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

functionalized graphitic mesoporous carbon as a stable support of Pt nanoparticles for oxygen reduction. Noncovalently functionalized graphitic mesoporous carbon as a stable...

52

1Nanomaterials for Energy Group Byungwoo Park  

E-Print Network [OSTI]

(2011). Advantages of Quantum-Dot-Sensitized Solar Cells #12;8Nanomaterials for Energy Group://bp.snu.ac.kr Cutting-Edge Nanomaterials for Energy: Solar Cell · Li+ Battery #12;2Nanomaterials for Energy Group Fuel Cell Solar Panel Portable Devices Solar Cell Phosphor Li+ Battery #12;4Nanomaterials for Energy

Cho, Jaephil

53

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

x-ray beam. Training - ESH590, Engineered Nanomaterials Orientation. Signs and Labeling - Containers with nanomaterials must be labeled "Caution - Engineered Nanomaterials"....

54

Experiment Hazard Class 14.2 - Nanomaterials - Liquid Suspension  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

x-ray beam. Training - ESH590, Engineered Nanomaterials Orientation. Signs and Labeling - Containers with nanomaterials must be labeled "Caution - Engineered Nanomaterials"....

55

Magnetic mesoporous materials for removal of environmental wastes  

SciTech Connect (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

56

Porous substrates filled with nanomaterials  

DOE Patents [OSTI]

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 nanotubes, disposed uniformly throughout the internal pores. The nanomaterial can be disposed in the middle of the monolith. In addition, a method for making a monolithic solid with both high surface area and good bulk electrical conductivity is provided. A porous substrate having a thickness of 100 microns or more and comprising macropores throughout its thickness is prepared. At least one catalyst is deposited inside the porous substrate. Subsequently, chemical vapor deposition is used to uniformly deposit a nanomaterial in the macropores throughout the thickness of the porous substrate. Applications include electrical energy storage, such as batteries and capacitors, and hydrogen storage.

Worsley, Marcus A.; Baumann, Theodore F.; Satcher, Jr., Joe H.; Stadermann, Michael

2014-08-19T23:59:59.000Z

57

1Nanomaterials for Energy Group Byungwoo Park  

E-Print Network [OSTI]

(2011). Advantages of Quantum-Dot-Sensitized Solar Cells #12;7Nanomaterials for Energy Group://bp.snu.ac.kr Cutting-Edge Nanomaterials for Energy: Solar Cell Nanophosphor Li+ Battery #12;2Nanomaterials for Energy for Energy Fuel Cell Li+ Battery Solar Panel Portable Devices Solar Cell White LED PDP Phosphor #12

Cho, Jaephil

58

Soft-Template-Synthesized Mesoporous Carbon for Oral Drug Delivery  

SciTech Connect (OSTI)

Template-synthesized mesoporous carbons were successfully used in in vitro investigations of controlled delivery of three model drugs, captopril, furosemide, and ranitidine hydrochloride. Captopril and furosemide exhibited desorption kinetics over 30 40 h, and ranitidine HCl had a complete release time of 5 10 h. As evident from the slow release kinetics, we contend that our mesoporous carbon is an improved drug-delivery medium compared to state-of-the-art porous silica-based substrates. The mesoporous carbons, synthesized from phloroglucinol and lignin, a synthetic and a sustainable precursor, respectively, exhibit BET surface area of 200 400 m2 g-1 and pore volume of 0.2 0.6 cm3 g-1. The phloroglucinol-based carbon has narrower pore widths and higher pore volume than the lignin-derived counterpart and maintains a longer release time. Numerical modeling of the release kinetics data reveals that the diffusivities of all the drugs from lignin-based carbon media are of equivalent magnitude (10-22 to 10-24 m2 s-1). However, a tailored reduction of pore width in the sorbent reduces the diffusivity of smaller drug molecules (captopril) by an order of magnitude. Thus, engineered pore morphology in our synthesized carbon sorbent, along with its potential to tailor the chemistry of its interaction with sorbet, can be exploited for optimal delivery system of a preferred drug within its therapeutic level and below the level of toxicity.

Saha, Dipendu [ORNL] [ORNL; Warren, Kaitlyn E [ORNL] [ORNL; Naskar, Amit K [ORNL] [ORNL

2014-01-01T23:59:59.000Z

59

Nanotechnology: Nanomaterials, Nanomedicine and Nanocars  

E-Print Network [OSTI]

Nanotechnology: Nanomaterials, Nanomedicine and Nanocars Wednesday March 21, 2012, Babbio 122, 11am and Technology Rice University, Houston, TX An overview of several of the nanotechnology research areas in our Nanotechnology in 2008, the NASA Space Act Award in 2008 for his development of carbon nanotube reinforced

Fisher, Frank

60

Characterizing Surface Acidic Sites in Mesoporous-Silica-Supported Tungsten  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed New Substation SitesStandingtheir AtmosphericAnalysisVents Using Osmotically

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

Screen-Printed Electrodes Modified with Functionalized Mesoporous Silica  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administrationcontroller systemsBi (2) Sr (2)ScienceScientists In thePrincetonScott Taylor,for

62

Templating Mesoporous Hierarchies in Silica Thin Films Using the Thermal  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security AdministrationcontrollerNanocrystallineForeignTechnology-Selection-ProcessHigh-Rate

63

Crosslinked Enzyme Aggregates in Hierarchically-Ordered Mesoporous Silica:  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed Newcatalyst phases on γ-Al2O3.Winter (Part 2)Crosscutting SuccessFAQsA

64

Thermal Conductivity of Cubic and Hexagonal Mesoporous Silica Thin Films  

E-Print Network [OSTI]

wire, serving as both a thermometer and a line heat source,as both heater and thermometer, was patterned on (A) (B)Diff Amp B Diff Amp Heater/thermometer on the sample I + V -

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

2009-01-01T23:59:59.000Z

65

Aligned mesoporous architectures and devices.  

SciTech Connect (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

66

Magnetic mesoporous material for the sequestration of algae  

DOE Patents [OSTI]

The present invention provides a magnetic mesoporous nanoparticle that includes a mesoporous silicate nanoparticle and iron oxide. The present invention also provides a method of using magnetic mesoporous nanoparticles to sequester microorganisms from a media.

Trewyn, Brian G.; Kandel, Kapil; Slowing, Igor Ivan; Lee, Show-Ling

2014-09-09T23:59:59.000Z

67

Application of Surface Analysis Methods to Nanomaterials: Summaryof...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Analysis Methods to Nanomaterials: Summaryof ISOTC 201 Technical Report: ISO 14187:2011 -Surface Application of Surface Analysis Methods to Nanomaterials: Summaryof ISOTC 201...

68

Dynamics of soft Nanomaterials captured by transmission electron...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Dynamics of soft Nanomaterials captured by transmission electron microscopy in liquid water. Dynamics of soft Nanomaterials captured by transmission electron microscopy in liquid...

69

Mesoporous Silicon Sponge as an Anti-Pulverization Structure...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Mesoporous Silicon Sponge as an Anti-Pulverization Structure for High-Performance Lithium-ion Battery Anodes. Mesoporous Silicon Sponge as an Anti-Pulverization Structure for...

70

Optimization of mesoporous carbon structures for lithium&ndash...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

mesoporous carbon structures for lithium–sulfur battery applications. Optimization of mesoporous carbon structures for lithium–sulfur battery applications. Abstract:...

71

Design and control of hierarchically structured nanomaterials  

E-Print Network [OSTI]

synthesis, many other metals have been attempted including barium, cesium, lithium, and many others along with looking at other synthesis parameters like starting reagents, compositions, and reaction conditions [31-42]. The structure of LTL contains... 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...

Carr, Charles Shane

2005-11-01T23:59:59.000Z

72

Carboxylic acid-grafted mesoporous material and its high catalytic activity in one-pot three-component coupling reaction  

SciTech Connect (OSTI)

A new carboxylic acid functionalized mesoporous organic polymer has been synthesized via in situ radical polymerization of divinylbenzene and acrylic acid using a mesoporous silica as a seed during the polymerization process under solvothermal conditions. The mesoporous material MPDVAA-1 has been thoroughly characterized employing powder XRD, solid state {sup 13}C cross polarization magic angle spinning-nuclear magnetic resonance, FT-IR spectroscopy, N{sub 2} sorption, HR-TEM, and NH{sub 3} temperature programmed desorption-thermal conductivity detector (TPD-TCD) analysis to understand its porosity, chemical environment, bonding, and surface properties. The mesoporous polymer was used as a catalyst for a three comp onent Biginelli condensation between various aldehydes, ?-keto esters, and urea/thioureas to give 3,4-dihydropyrimidine-2(1H)-ones. The reactions were carried out under conventional heating as well as solvent-free microwave irradiation of solid components, and in both the cases, the mesoporous polymer MPDVAA-1 proved to be a powerful, robust, and reusable catalyst with high catalytic efficiency.

Gomes, Ruth; Bhaumik, Asim [Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India); Dutta, Saikat [Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan (China)

2014-11-01T23:59:59.000Z

73

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

74

1Nanomaterials for Energy Group Prof. Byungwoo Park  

E-Print Network [OSTI]

). Advantages of Quantum-Dot-Sensitized Solar Cells #12;6Nanomaterials for Energy Group Electrolyte://bp.snu.ac.kr Cutting-Edge Nanomaterials for Energy: Solar Cell Nanophosphor Li+ Battery #12;2Nanomaterials for Energy for Energy Li+ Battery Phosphor Solar cell Nanomaterials for Energy * #12;Quantum-Dot- and Dye

Cho, Jaephil

75

1Nanomaterials for Energy Group Prof. Byungwoo Park  

E-Print Network [OSTI]

). Advantages of Quantum-Dot-Sensitized Solar Cells #12;6Nanomaterials for Energy Group Electrolyte://bp.snu.ac.kr Cutting-Edge Nanomaterials for Energy: Solar Cell · Nanophosphor · Li+ Battery #12;2Nanomaterials for Energy Group Vehicle Laptop Solar Panel Portable Devices White LED PDP Nanoscale Control: Nanomaterials

Cho, Jaephil

76

Kinetics of Silica Polymerization  

E-Print Network [OSTI]

geothermal brines:’ Avoidance or minimization of silica supersaturation Supersaturation can be avoided by preventing cooling

Weres, Oleh

2011-01-01T23:59:59.000Z

77

Surfactant-directed synthesis of mesoporous films made single-step by a tandem photosol-gel/photocalcination route  

SciTech Connect (OSTI)

In view of their technological impact in materials chemistry, a simplified and more efficient synthetic route to mesoporous films is highly sought. We report, herein, a smart UV-mediated approach coupling in a one-stage process sol-gel photopolymerization and photoinduced template decomposition/ablation to making mesoporous silica films. Performed at room temperature with a solvent-free solution of silicate precursor and amphiphilic poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) block copolymer, the synthesis relies on photoacid generation to induce the fast formation (?10 min) of mesostructured silica/surfactant domains. Continuation of UV exposure for three additional hours enables subsequent and complete photodegradation of the polyether copolymer, resulting in ordered or disordered mesoporous silica film. One of the most attractive features is that the one-step procedure relies on a continuous illumination provided by the same conventional medium-pressure Hg-Xe arc lamp equipped with a 254 nm reflector to enhance the emission of energetic photons <300 nm. In addition to X-ray diffraction and transmission electron microscopy, time-resolved Fourier transform infrared spectroscopy has proved to be a powerful in situ technique to probe the different chemical transformations accompanying irradiation. Photocalcination strengthens the inorganic network, while allowing to preserve a higher fraction of residual silanol groups compared with thermal calcination. A polyether chain degradation mechanism based on oxygen reactive species-mediated photo-oxidation is proposed.

De Paz-Simon, Héloïse; Chemtob, Abraham, E-mail: abraham.chemtob@uha.fr; Croutxé-Barghorn, Céline [Laboratory of Macromolecular Photochemistry and Engineering, ENSCMu, University of Haute-Alsace, 3 bis rue Alfred Werner, 68093 Mulhouse Cedex (France); Rigolet, Séverinne; Michelin, Laure; Vidal, Loïc; Lebeau, Bénédicte [Institut de Science des Matériaux de Mulhouse, UMR-CNRS 7361, University of Haute-Alsace, 3 rue Alfred Werner, 68093 Mulhouse Cedex (France)

2014-11-01T23:59:59.000Z

78

Toxicology and cellular effect of manufactured nanomaterials  

DOE Patents [OSTI]

The increasing use of nanotechnology in consumer products and medical applications underlies the importance of understanding its potential toxic effects to people and the environment. Herein are described methods and assays to predict and evaluate the cellular effects of nanomaterial exposure. Exposing cells to nanomaterials at cytotoxic doses induces cell cycle arrest and increases apoptosis/necrosis, activates genes involved in cellular transport, metabolism, cell cycle regulation, and stress response. Certain nanomaterials induce genes indicative of a strong immune and inflammatory response within skin fibroblasts. Furthermore, the described multiwall carbon nanoonions (MWCNOs) can be used as a therapeutic in the treatment of cancer due to its cytotoxicity.

Chen, Fanqing

2014-07-22T23:59:59.000Z

79

Silica extraction from geothermal water  

DOE Patents [OSTI]

A method of producing silica from geothermal fluid containing low concentration of the silica of less than 275 ppm includes the steps of treating the geothermal fluid containing the silica by reverse osmosis treatment thereby producing a concentrated fluid containing the silica, seasoning the concentrated fluid thereby producing a slurry having precipitated colloids containing the silica, and separating the silica from the slurry.

Bourcier, William L; Bruton, Carol J

2014-09-23T23:59:59.000Z

80

Chemical Functionalization, Self-Assembly, and Applications of Nanomaterials and Nanocomposites  

SciTech Connect (OSTI)

This special issue addresses the research studies on chemical functionalization, self-assembly, and applications of nanomaterials and nanocomposites. It contains twentyfour articles including two reviews and twenty-two research articles. It is used to create new functional nanomaterials and nanocomposites with a variety of sizes and morphologies such as Zn/Al layered double hydroxide, tin oxide nanowires, FeOOH-modified anion resin, Au nanoclusters silica composite nanospheres, Ti-doped ZnO sol-composite films, TiO2/ZnO composite, graphene oxide nanocomposites, LiFePO4/C nanocomposites, and chitosan nanoparticles. These nanomaterials and nanocomposites have widespread applications in tissue engineering, antitumor, sensors, photoluminescence, electrochemical, and catalytic properties. In addition, this themed issue includes some research articles about self-assembly systems covering organogels and Langmuir films. Furthermore, B. Blasiak et al. performed a literature survey on the recent advances in production, functionalization, toxicity reduction, and application of nanoparticles in cancer diagnosis, treatment, and treatment monitoring. P. Colson et al. performed a literature survey on the recent advances in nanosphere lithography due to its compatibility with wafer-scale processes as well as its potential to manufacture a wide variety of homogeneous one-, two-, or three-dimensional nanostructures.

Jiao, Tifeng [Yanshan University; Yan, Xingbin [Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences; Balan, Lavinia [French National Centre for Scientific Research (CNRS), Institute of Materials Science of Mulhouse (IS2M), France; Stepanov, Andrey [Russian Academy of Sciences (RAS), Kazan Physical-Technical Institute, Russia; Chen, Xinqing [Hong Kong University of Science and Technology, Hong Kong; Hu, Michael Z. [ORNL

2014-01-01T23:59:59.000Z

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.


81

Curvature effects on carbon nanomaterials: Exohedral versus endhohedra...  

Office of Scientific and Technical Information (OSTI)

Curvature effects on carbon nanomaterials: Exohedral versus endhohedral supercapacitors Re-direct Destination: Capacitive energy storage mechanisms in nanoporous carbon...

82

Grand Challenges of Characterization & Modeling of Cellulose Nanomaterials  

Broader source: Energy.gov [DOE]

Presentation for the Sustainable Nanomaterials Workshop by U.S. Forest Service and Purdue University held on June 26, 2012

83

The Tactical and Strategic Implementation of Sustainable Nanomaterials  

Broader source: Energy.gov [DOE]

Presentation for the Sustainable Nanomaterials Workshop by Verso Paper Corp. and TAPPI held on June 26, 2012

84

Probing Porosity and Pore Interconnectivity in Crystalline Mesoporous...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Porosity and Pore Interconnectivity in Crystalline Mesoporous TiO2 Using Hyperpolarized Xe-129 NMR. Probing Porosity and Pore Interconnectivity in Crystalline Mesoporous TiO2 Using...

85

Preparation of irregular mesoporous hydroxyapatite  

SciTech Connect (OSTI)

An irregular mesoporous hydroxyapatite (meso-HA), Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}, is successfully prepared from Ca(NO{sub 3}){sub 2}.4H{sub 2}O and NH{sub 4}H{sub 2}PO{sub 4} using surfactant cetyltrimethyl ammonium bromide (CTAB) as template. Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) results reveal that the positive head of CTAB is assembled on the surface precipitated HA and much NH{sub 4}{sup +} is enclosed in precipitated HA before calcination. Field scanning electron microscope (FSEM) reveals that there exist many interconnected pores throughout the HA reticular skeleton. Nitrogen adsorption-desorption experiment exhibits a mesoporous material type IV curve, and pore size distribution calculated from the desorption branch of the isotherms based on Barrett-Joyner-Halenda (BJH) model shows that most pores throughout the HA reticular skeleton are sized at about 40 nm, but the pores are not uniform on the whole, owning to decomposition of the 'organic' CTAB templating structures and ammonium salt enclosed in the precipitated HA. The specific surface area of irregular meso-HA is calculated to be 37.6 m{sup 2}/g according to the Brunauer-Emmett-Teller (BET) equation. Moreover, after polylactic acid/meso-HA (PLA/meso-HA) composites degraded 12 weeks in normal saline at 37 deg. C, the interconnected pores throughout the HA skeleton were enlarged and sized in micron degree, which resemble trabecular bone structure very much.

Wang Hualin [School of Chemical Technology, Hefei University of Technology, Hefei, Anhui 230009 (China)], E-mail: hlwang@hfut.edu.cn; Zhai Linfeng; Li Yanhong; Shi Tiejun [School of Chemical Technology, Hefei University of Technology, Hefei, Anhui 230009 (China)

2008-06-03T23:59:59.000Z

86

Silica in Protoplanetary Disks  

E-Print Network [OSTI]

Mid-infrared spectra of a few T Tauri stars (TTS) taken with the Infrared Spectrograph (IRS) on board the Spitzer Space Telescope show prominent narrow emission features indicating silica (crystalline silicon dioxide). Silica is not a major constituent of the interstellar medium; therefore, any silica present in the circumstellar protoplanetary disks of TTS must be largely the result of processing of primitive dust material in the disks surrouding these stars. We model the silica emission features in our spectra using the opacities of various polymorphs of silica and their amorphous versions computed from earth-based laboratory measurements. This modeling indicates that the two polymorphs of silica, tridymite and cristobalite, which form at successively higher temperatures and low pressures, are the dominant forms of silica in the TTS of our sample. These high temperature, low pressure polymorphs of silica present in protoplanetary disks are consistent with a grain composed mostly of tridymite named Ada found in the cometary dust samples collected from the STARDUST mission to Comet 81P/Wild 2. The silica in these protoplanetary disks may arise from incongruent melting of enstatite or from incongruent melting of amorphous pyroxene, the latter being analogous to the former. The high temperatures of 1200K-1300K and rapid cooling required to crystallize tridymite or cristobalite set constraints on the mechanisms that could have formed the silica in these protoplanetary disks, suggestive of processing of these grains during the transient heating events hypothesized to create chondrules.

B. A. Sargent; W. J. Forrest; C. Tayrien; M. K. McClure; A. Li; A. R. Basu; P. Manoj; D. M. Watson; C. J. Bohac; E. Furlan; K. H. Kim; J. D. Green; G. C. Sloan

2008-11-21T23:59:59.000Z

87

1 | P a g e MANIPULATING NANOMATERIALS  

E-Print Network [OSTI]

is reprinted from the fall 2009 issue of the Faculty of Engineering Dean's Report. Nanomaterials are, the de-icing sand used on roads in winter accumulates inside the rims of bus wheels and erodes microseconds provides the energy to deposit and fuse materials without causing them to lose their nanostructure

Barthelat, Francois

88

Nanomaterials for Energy and Electronics Materials Science  

E-Print Network [OSTI]

Synthesis of ZnO Aggregates and Their Application in Dye-sensitized Solar Cells Nanomaterials for Energy-phase Metal Oxide Nanostructures #12;Synthesis of ZnO Aggregates and Their Application in Dye-sensitized Solar require major breakthroughs to meet the long-term goal of very low cost ($0.40/kWh).2-6 Dye-sensitized

Cao, Guozhong

89

Silica Scaling Removal Process  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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

90

Corrosion behavior of mesoporous transition metal nitrides  

SciTech Connect (OSTI)

Transition metal nitrides (TMN) have many desirable characteristics such as high hardness and good thermal stability under reducing conditions. This work reports an initial survey of the chemical stability of mesoporous TMNs (TM=Nb, V, Cr and Ti) in water at 80 °C at neutral, acidic and alkaline pH. The mesoporous TMNs had specific surface areas of 25–60 m{sup 2}/g with average pore sizes ranging from 10 to 50 nm. The high surface areas of these materials enhance the rate of corrosion per unit mass over that of a bulk material, making detection of corrosion much easier. The products were characterized by Rietveld refinement of powder X-ray diffraction (PXRD) patterns and by scanning electron microscopy (SEM). Several nitrides have corrosion rates that are, within error, not distinguishable from zero (±1 Å/day). Of the nitrides examined, CrN appears to be the most corrosion resistant under acidic conditions. None of the nitrides studied are corrosion resistant under alkaline conditions. - Graphical abstract: Corrosion behavior of mesoporous transition metal nitrides (TM=Nb, V, Cr and Ti) in acidic and alkaline solutions at 80 °C for 2 weeks. Display Omitted - highlights: • Corrosion rates of mesoporous transition metal nitrides in aqueous solution is reported. • The mesoporous TMNs had surface areas of 25–60 m{sup 2}/g. • CrN is the most corrosion resistant under the conditions studied.

Yang, Minghui, E-mail: m.yang@cornell.edu [Department of Chemistry, Cornell University, Ithaca 14853-1301, NY (United States); Allen, Amy J.; Nguyen, Minh T. [Department of Chemistry, Cornell University, Ithaca 14853-1301, NY (United States); Ralston, Walter T. [College of Chemistry, University of California, Berkeley 94720-1460, CA (United States); MacLeod, Michelle J. [Department of Chemistry, Massachusetts Institute of Technology, Cambridge 02139-4307, MA (United States); DiSalvo, Francis J., E-mail: fjd3@cornell.edu [Department of Chemistry, Cornell University, Ithaca 14853-1301, NY (United States)

2013-09-15T23:59:59.000Z

91

Location of laccase in ordered mesoporous materials  

SciTech Connect (OSTI)

The functionalization with amine groups was developed on the SBA-15, and its effect in the laccase immobilization was compared with that of a Periodic Mesoporous Aminosilica. A method to encapsulate the laccase in situ has now been developed. In this work, spherical aberration (C{sub s}) corrected scanning transmission electron microscopy combined with high angle annular dark field detector and electron energy loss spectroscopy were applied to identify the exact location of the enzyme in the matrix formed by the ordered mesoporous solids.

Mayoral, Álvaro [Laboratorio de Microscopias Avanzadas, Instituto de Nanociencia de Aragon, Universidad de Zaragoza, Edificio I - D, Mariano Esquillor, 50018 Zaragoza (Spain); Gascón, Victoria; Blanco, Rosa M.; Márquez-Álvarez, Carlos; Díaz, Isabel, E-mail: idiaz@icp.csic.es [Instituto de Catálisis y Petroleoquímica, CSIC, c/Marie Curie 2, 28049 Madrid (Spain)

2014-11-01T23:59:59.000Z

92

Nanomaterials for Extracting Hydrogen from Water  

E-Print Network [OSTI]

to catalyze water oxidation. K E Y A C C O M P L I S H M E N T S Produced highly active iron oxide (hematiteNanomaterials for Extracting Hydrogen from Water P R O J E C T L E A D E R : Veronika Szalai (NIST water. R E F E R E N C E Effect of tin doping on -Fe2 O3 photoanodes for water splitting, C. D. Bohn, A

93

Advancements Toward the Greener Processing of Engineered Nanomaterials...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Processing of Engineered Nanomaterials -- Effect of Core Size on the Dispersibility and Abstract: In this work, we explore the dispersibility of octanethiol-stabilized gold...

94

aluminum-rich mesoporous mfi: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

mesoporous carbon-based composites for confinement of Eue Mesoporous polymer-carbon composite (CMPEICMK-3) materials were successfully prepared. After Eu(III) ions were loaded...

95

Stepwise synthesis, characterization, and electrochemical properties of ordered mesoporous carbons containing well-dispersed Pt nanoparticles using a functionalized template route  

SciTech Connect (OSTI)

A stepwise method is described for the accurately controlled growth of Pt nanoparticles supported on ordered mesoporous carbons (Pt-OMC) by the nanocasting of carbon and metal precursors in the pore channels of mesoporous silicas functionalized with Si-H groups. Results obtained from N{sub 2} adsorption/desorption isotherms and transmission electron microscopy showed well-dispersed Pt nanoparticles (2-3 nm) on Pt-OMC with high surface area (837 m{sup 2} g{sup -1}) and regular pore channels (2.9 nm), which facilitate reactant/product diffusion. X-ray diffraction and X-ray photoelectron spectroscopy indicated that Pt nanoparticles in the Pt-OMC sample were mostly present in the metallic form of a face-centered cubic (fcc) crystalline structure. The Pt-OMC catalyst was found to have superior electrocatalytic properties during oxygen reduction reaction as compared to typical commercial electrocatalysts. - Graphical abstract: A novel procedure has been developed to synthesize ordered carbon mesoporous carbons (OMC) containing well-dispersed and highly electrocatalytic Pt nanoparticles (Pt-OMC) for oxygen reduction reaction. Highlights: > A novel method to incorporate nanosized Pt particles on nanostructure carbons. > Functionalized silica templates were used to control size and distribution of Pt nanoparticles. > Electrochemical measurements of oxygen reduction demonstrated high catalytic activity compared to common commercial catalysts.

Liu, Shou-Heng, E-mail: shliu@kuas.edu.tw [Department of Chemical and Materials Engineering, National Kaohsiung University of Applied Sciences, Kaohsiung 80778, Taiwan (China); Chen, Shih-Che [Department of Chemical and Materials Engineering, National Kaohsiung University of Applied Sciences, Kaohsiung 80778, Taiwan (China)

2011-09-15T23:59:59.000Z

96

Mesoporous electrodes for hydrogen production | Center for Bio...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Center News Research Highlights Center Research News Media about Center Center Video Library Bisfuel Picture Gallery Mesoporous electrodes for hydrogen production 24 Oct 2012...

97

Nanoscience on the Timescale of Electrons Ultrafast Spectroscopy of Nanomaterials  

E-Print Network [OSTI]

Nanoscience on the Timescale of Electrons Ultrafast Spectroscopy of Nanomaterials Pat Kambhampati with it??? ·How does it actually work??? #12;Nanoscience on the Ultrafast Timescale Pat Kambhampati, Mc? #12;Nanoscience on the Ultrafast Timescale Pat Kambhampati, McGill Chemistry Nanomaterial based

Kambhampati, Patanjali

98

1Electromaterials and Nanomaterials Group Prof. Byungwoo Park  

E-Print Network [OSTI]

for Energy #12;Quantum-Dot- and Dye-Sensitized Solar Cells Prototype dye-sensitized solar cell panel from SONY Dye-sensitized solar cells from KIST #12;4Electromaterials and Nanomaterials Group e-e- h Working Principles of Sensitized Solar Cells #12;5Electromaterials and Nanomaterials Group

Park, Byungwoo

99

Nanomaterial Labels in Electrochemical Immunosensors and Immunoassays. |  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the Contributions andData andFleet TestAccounts andTheMisalignedEMSL Nanomaterial

100

Nanomaterials for Sensing and Electrocatalysis. | EMSL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the Contributions andData andFleet TestAccounts andTheMisalignedEMSLNanomaterials for

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

Kinetics of silica polymerization  

SciTech Connect (OSTI)

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

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

1980-05-01T23:59:59.000Z

102

Cellulose Nanomaterials: The Sustainable Material of Choice for the 21st Century  

Broader source: Energy.gov [DOE]

Presentation for the Sustainable Nanomaterials Workshop by USDA Forest Service held on June 26, 2012

103

Packaging Materials of the 21st Century: "Sustainable Nano-Materials- Benefits to the industry"  

Broader source: Energy.gov [DOE]

Presentation for the Sustainable Nanomaterials Workshop by Nanocellulose Work Group held on June 26, 2012

104

Sustainable Nano-Materials: What is happening at the cellular level?  

Broader source: Energy.gov [DOE]

Presentation for the Sustainable Nanomaterials Workshop by Georgia Institute of Technology held on June 26, 2012

105

Sructure and dynamics of fluids in micropous and mesoporous earth and engineered materials  

SciTech Connect (OSTI)

The behavior of liquids in confined geometries (pores, fractures) typically differs, due to the effects of large internal surfaces and geometri-cal confinement, from their bulk behavior in many ways. Phase transitions (i.e., freezing and capillary condensation), sorption and wetting, and dy-namical properties, including diffusion and relaxation, may be modified, with the strongest changes observed for pores ranging in size from <2 nm to 50 nm the micro- and mesoporous regimes. Important factors influ-encing the structure and dynamics of confined liquids include the average pore size and pore size distribution, the degree of pore interconnection, and the character of the liquid-surface interaction. While confinement of liq-uids in hydrophobic matrices, such as carbon nanotubes, or near the sur-faces of mixed character, such as many proteins, has also been an area of rapidly growing interest, the confining matrices of interest to earth and ma-terials sciences usually contain oxide structural units and thus are hydro-philic. The pore size distribution and the degree of porosity and inter-connection vary greatly amongst porous matrices. Vycor, xerogels, aerogels, and rocks possess irregular porous structures, whereas mesopor-ous silicas (e.g., SBA-15, MCM-41, MCM-48), zeolites, and layered sys-tems, for instance clays, have high degrees of internal order. The pore type and size may be tailored by means of adjusting the synthesis regimen. In clays, the interlayer distance may depend on the level of hydration. Al-though studied less frequently, matrices such as artificial opals and chry-sotile asbestos represent other interesting examples of ordered porous structures. The properties of neutrons make them an ideal probe for com-paring the properties of bulk fluids with those in confined geometries. In this chapter, we provide a brief review of research performed on liquids confined in materials of interest to the earth and material sciences (silicas, aluminas, zeolites, clays, rocks, etc.), emphasizing those neutron scattering techniques which assess both structural modification and dynamical behav-ior. Quantitative understanding of the complex solid-fluid interactions under different thermodynamic situations will impact both the design of bet-ter substrates for technological applications (e.g., chromatography, fluid capture, storage and release, and heterogeneous catalysis) as well as our fundamental understanding of processes encountered in the environment (i.e., fluid and waste mitigation, carbon sequestration, etc.).

Cole, David R [ORNL; Mamontov, Eugene [ORNL; Rother, Gernot [ORNL

2009-01-01T23:59:59.000Z

106

Preparation of polypyrrole-incorporated mesoporous carbon-based composites for confinement of Eu(III) within mesopores  

E-Print Network [OSTI]

e Mesoporous polymer-carbon composite (CMPEI/CMK-3) materials were successfully preparedPreparation of polypyrrole-incorporated mesoporous carbon-based composites for confinement of Eu processes. 1. Introduction A number of organic-inorganic or organic-organic composite materials have been

Boo, Jin-Hyo

107

Mesoporous Carbon-based Materials for Alternative Energy Applications  

E-Print Network [OSTI]

O. M. Yaghi (2003). "Hydrogen Storage in Microporous Metal-Nanomaterials for Hydrogen Storage Applications: A Review."K. P. de Jong (2001). "Hydrogen storage using physisorption-

Cross, Kimberly Michelle

2012-01-01T23:59:59.000Z

108

MTL ANNUAL RESEARCH REPORT 2014 Nanotechnology 145 Nanotechnology, Nanomaterials  

E-Print Network [OSTI]

MTL ANNUAL RESEARCH REPORT 2014 Nanotechnology 145 Nanotechnology, Nanomaterials Synthesize Silver Metal Chalcogenides ........................................165 #12;146 Nanotechnology MTL ANNUAL RESEARCH REPORT 2014 #12;MTL ANNUAL RESEARCH REPORT 2014 Nanotechnology 147 Synthesize Silver Nanoprisms

Reif, Rafael

109

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

110

Femtosecond time-resolved spectroscopy of coherent oscillations in nanomaterials  

E-Print Network [OSTI]

FEMTOSECOND TIME-RESOLVED SPECTROSCOPY OF COHERENT OSCILLATIONS IN NANOMATERIALS A Dissertation by SERGUEI JEREBTSOV Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree... of DOCTOR OF PHILOSOPHY May 2007 Major Subject: Physics FEMTOSECOND TIME-RESOLVED SPECTROSCOPY OF COHERENT OSCILLATIONS IN NANOMATERIALS A Dissertation by SERGUEI JEREBTSOV Submitted to the Office of Graduate Studies of Texas A&M University in partial...

Jerebtsov, Serguei Nikolaevich

2009-05-15T23:59:59.000Z

111

NiO-silica based nanostructured materials obtained by microemulsion assisted sol-gel procedure  

SciTech Connect (OSTI)

Graphical abstract: TEM micrograph of NiO/SiO{sub 2} nanoparticles. Highlights: {yields} Microemulsion assisted sol-gel procedure for NiO silica nanomaterials synthesis. {yields} Controlling the size and shape of nanoparticles and avoiding their aggregation. {yields} Narrow band-gap semiconductors (energies <3 eV) absorbing VIS or near-UV light biologically and chemically inert semiconductors entrapping/coating in silica network. {yields} Low cost as the microemulsion is firstly used in water metallic cation extraction. -- Abstract: NiO-silica based materials have been synthesized by microemulsion assisted sol-gel procedure. The versatility of these soft nanotechnology techniques has been exploited in order to obtain different types of nanostructures, such as NiO nanoparticles, NiO silica coated nanoparticles and NiO embedded in silica matrix. These materials have been characterized by adequate structural and morphology techniques: DLS, HR-TEM/SAED, BET, AFM. Optical and semiconducting properties (band-gap values) of the synthesized materials have been quantified by means of VIS-NIR diffuse reflectance spectra, thus demonstrating their applicative potential in various electron transfer phenomena such as photocatalysis, electrochromic thin films, solid oxide fuel cells.

Mihaly, M.; Comanescu, A.F. [University POLITEHNICA Bucharest, Faculty of Applied Chemistry and Materials Science, 1 Polizu, 011061 Bucharest (Romania)] [University POLITEHNICA Bucharest, Faculty of Applied Chemistry and Materials Science, 1 Polizu, 011061 Bucharest (Romania); Rogozea, A.E. [ILIE MURGULESCU Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest (Romania)] [ILIE MURGULESCU Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest (Romania); Vasile, E. [METAV Research and Development, 31 C.A. Rosetti, 020011 Bucharest (Romania)] [METAV Research and Development, 31 C.A. Rosetti, 020011 Bucharest (Romania); Meghea, A., E-mail: a.meghea@gmail.com [University POLITEHNICA Bucharest, Faculty of Applied Chemistry and Materials Science, 1 Polizu, 011061 Bucharest (Romania)

2011-10-15T23:59:59.000Z

112

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

113

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

114

Challenges for In vitro to in Vivo Extrapolation of Nanomaterial Dosimetry for Human Risk Assessment  

SciTech Connect (OSTI)

The proliferation in types and uses of nanomaterials in consumer products has led to rapid application of conventional in vitro approaches for hazard identification. Unfortunately, assumptions pertaining to experimental design and interpretation for studies with chemicals are not generally appropriate for nanomaterials. The fate of nanomaterials in cell culture media, cellular dose to nanomaterials, cellular dose to nanomaterial byproducts, and intracellular fate of nanomaterials at the target site of toxicity all must be considered in order to accurately extrapolate in vitro results to reliable predictions of human risk.

Smith, Jordan N.

2013-11-01T23:59:59.000Z

115

Nanomaterials driven energy, environmental and biomedical research  

SciTech Connect (OSTI)

We have developed state-of-the-art nanomaterials such as nanofibers, nanotubes, nanoparticles, nanocatalysts and nanostructures for clean energy, environmental and biomedical research. Energy can neither be created nor be destroyed, but it can be converted from one form to another. Based on this principle, chemical energy such as hydrogen has been produced from water electrolysis at a much lower voltage using RuO{sub 2} nanoparticles on the Si wafer substrate. Once the hydrogen is produced from the clean sources such as solar energy and water, it has to be stored by physisorption or chemisorption processes on to the solid state systems. For the successful physical adsorption of hydrogen molecule, we have developed novel polyaniline nanostructures via chemical templating and electrospinning routes. Chemical or complex hydrides involving nano MgH{sub 2} and transition metal nanocatalysts have been synthesized to tailor both the thermodynamics and kinetics of hydrogen (chemi) sorption respectively. Utilization of solar energy (UV-Vis) and a coupling of novel semiconductor oxide nanoparticles have been recently demonstrated with enhancement in photo-oxidation and/or photo-reduction processes for the water/air detoxification and sustainable liquid fuel production respectively. Magnetic nanoparticles such as ZnFe{sub 2}O{sub 4} have been synthesized and optimized for biomedical applications such as targeted drug delivery and tumor diagnostic sensing (MRI)

Sharma, Prakash C.; Srinivasan, Sesha S.; Wilson, Jeremiah F. [Department of Physics, College of Arts and Sciences, Tuskegee University, Tuskegee, AL 36088 (United States)

2014-03-31T23:59:59.000Z

116

SoftTemplated Mesoporous CarbonCarbon Nanotube Composites for...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Mesoporous Carbon-Carbon Nanotube Composites for High Performance Lithium-ion Batteries Dr. B. K. Guo, Dr. X. Q. Wang, Dr. P. F. Fulvio , Dr. S. M. Mahurin, Dr. X.-G. Sun,...

117

Near-infrared emission from mesoporous crystalline germanium  

SciTech Connect (OSTI)

Mesoporous crystalline germanium was fabricated by bipolar electrochemical etching of Ge wafer in HF-based electrolyte. It yields uniform mesoporous germanium layers composed of high density of crystallites with an average size 5-7 nm. Subsequent extended chemical etching allows tuning of crystallites size while preserving the same chemical composition. This highly controllable nanostructure exhibits photoluminescence emission above the bulk Ge bandgap, in the near-infrared range (1095-1360nm) with strong evidence of quantum confinement within the crystallites.

Boucherif, Abderraouf; Aimez, Vincent; Arès, Richard, E-mail: richard.ares@usherbrooke.ca [Institut Interdisciplinaire d’Innovation Technologique (3IT), Université de Sherbrooke, 3000 Boulevard Université, Sherbrooke, J1K OA5, Québec (Canada); Laboratoire Nanotechnologies Nanosystèmes (LN2)-CNRS UMI-3463, Université de Sherbrooke, 3000 Boulevard Université, Sherbrooke, J1K OA5, Québec (Canada); Korinek, Andreas [Canadian Centre for Electron Microscopy, Brockhouse Institute for Materials Research, McMaster University, Hamilton, Ontario, L8S 4M1 (Canada)

2014-10-15T23:59:59.000Z

118

Synthesis of acid-base bifunctional mesoporous materials by oxidation and thermolysis  

SciTech Connect (OSTI)

Graphical abstract: A novel and efficient method has been developed for the synthesis of acid-base bifunctional catalyst. The obtained sample of SO{sub 3}H-MCM-41-NH{sub 2} containing amine and sulfonic acids exhibits excellent catalytic activity in aldol condensation reaction. Research highlights: {yields} Synthesize acid-base bifunctional mesoporous materials SO{sub 3}H-MCM-41-NH{sub 2}. {yields} Oxidation and then thermolysis to generate acidic site and basic site. {yields} Exhibit good catalytic performance in aldol condensation reaction between acetone and various aldehydes. -- Abstract: A novel and efficient method has been developed for the synthesis of acid-base bifunctional catalyst SO{sub 3}H-MCM-41-NH{sub 2}. This method was achieved by co-condensation of tetraethylorthosilicate (TEOS), 3-mercaptopropyltrimethoxysilane (MPTMS) and (3-triethoxysilylpropyl) carbamicacid-1-methylcyclohexylester (3TAME) in the presence of cetyltrimethylammonium bromide (CTAB), followed by oxidation and then thermolysis to generate acidic site and basic site. X-ray diffraction (XRD) and transmission electron micrographs (TEM) show that the resultant materials keep mesoporous structure. Thermogravimetric analysis (TGA), X-ray photoelectron spectra (XPS), back titration, solid-state {sup 13}C CP/MAS NMR and solid-state {sup 29}Si MAS NMR confirm that the organosiloxanes were condensed as a part of the silica framework. The bifunctional sample (SO{sub 3}H-MCM-41-NH{sub 2}) containing amine and sulfonic acids exhibits excellent acid-basic properties, which make it possess high activity in aldol condensation reaction between acetone and various aldehydes.

Yu, Xiaofang [College of Chemistry, Jilin University, Jiefang Road 2519, Changchun 130023 (China)] [College of Chemistry, Jilin University, Jiefang Road 2519, Changchun 130023 (China); Zou, Yongcun [State Key Laboratory of Inoranic Synthesis and Preparative Chemistryg, College of Chemistry, Jilin University, Changchun 130012 (China)] [State Key Laboratory of Inoranic Synthesis and Preparative Chemistryg, College of Chemistry, Jilin University, Changchun 130012 (China); Wu, Shujie; Liu, Heng [College of Chemistry, Jilin University, Jiefang Road 2519, Changchun 130023 (China)] [College of Chemistry, Jilin University, Jiefang Road 2519, Changchun 130023 (China); Guan, Jingqi, E-mail: guanjq@jlu.edu.cn [College of Chemistry, Jilin University, Jiefang Road 2519, Changchun 130023 (China)] [College of Chemistry, Jilin University, Jiefang Road 2519, Changchun 130023 (China); Kan, Qiubin, E-mail: qkan@jlu.edu.cn [College of Chemistry, Jilin University, Jiefang Road 2519, Changchun 130023 (China)] [College of Chemistry, Jilin University, Jiefang Road 2519, Changchun 130023 (China)

2011-06-15T23:59:59.000Z

119

A NEW CLASS OF MESOPOROUS ALUMINOPHOSPHATES FOR APPLICATION IN PERTOLEUM REFINING  

SciTech Connect (OSTI)

This project focuses on the synthesis of mesoporous aluminophosphate and aluminosilicates as catalysts for application in the conversion of large petroleum feedstock compounds to useful middle distillates and naphtha transportation fuels. Summarized herein, is our research progress for September 1, 2001 to August 31, 2002. The synthesis of aluminophosphates in the presence of nonionic surfactants and block co-polymers were explored over a wide range of synthesis variables such as temperature, Al/P ratio, pH and surfactants/polymer concentrations. In most cases, the resulting products were found to be amorphous. A partially ordered aluminophosphate mesophase was obtained in the presence of Brij 56 non-ionic surfactant. Further characterization to determine the phase type (e.g. hexagonal lamellar or cubic) of this product is pending. The amorphous nature of the products obtained using these classes of surfactants are in contrast to highly ordered aluminophosphates mesophases obtained in the presence of cationic quaternary ammonium surfactants, such as cetyltrimethylammonium detailed in a previous report. The synthesis of pure-silica and aluminosilicate mesophases of different type and quality were also conducted over a wide range of variables such as temperature, Si/Al ratio, pH and surfactants/polymer concentrations. However characterization of the phase type and quality of the materials produced is pending due to a severe and extended malfunction of the X-Ray Diffractometer. Nitrogen porosimetry of selected calcined samples showed various absorption isotherm with some samples showing type IV with a large step in the mesoporous range. Surface area of the samples varied and maximized at approximately 1000 m{sup 2}/g, which is typically reported for materials of this type. Further characterization of the sample will be conducted following repair of the X-Ray Diffractometer.

Conrad Ingram, Ph.D.

2003-02-12T23:59:59.000Z

120

Fabrication of functional nanomaterials using flame assisted spray pyrolysis  

SciTech Connect (OSTI)

Flame assisted spray pyrolysis (FASP) is a class of synthesis method for nanomaterials fabrication. The ability to control nanomaterials characteristics and easy to be-scaled up are the main features of FASP. The crystallinity and particles size of the prepared nanomaterials can be easily controlled by variation of fuel flow rate. The precursor concentration, carrier gas flow rate, and carrier gas can be also used to control the prepared nanomaterials. Energy related nanomaterials preparation uses as the example case in FASP application. These material are yttrium aluminum garnet (YAG:Ce) and tungsten oxide (WO{sub 3}). It needs strategies to produce these materials into nano-sized order. YAG:Ce nanoparticles only can be synthesized by FASP using the urea addition. The decomposition of urea under high temperature of flame promotes the breakage of YAG:Ce particles into nanoparticles. In the preparation of WO{sub 3}, the high temperature flame can be used to gasify WO{sub 3} solid material. As a result, WO{sub 3} nanoparticles can be prepared easily. Generally, to produce nanoparticles via FASP method, the boiling point of the material is important to determine the strategy which will be used.

Purwanto, Agus, E-mail: aguspur@uns.ac.id [Chemical Engineering Department, Faculty of Engineering, Sebelas Maret University, Surakarta 632112 (Indonesia)

2014-02-24T23:59:59.000Z

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

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

SciTech Connect (OSTI)

The development of integrated artificial photosynthetic systems for the direct conversion of carbon dioxide and water to fuel depends on the availability of efficient and robust catalysts for the chemical transformations. Catalysts need to exhibit turnover frequency (TOF) and density (hence size) commensurate with the solar flux at ground level (1000Wm2, airmass (AM) 1.5)[1]to avoid wasting of incidentsolar photons. For example, a catalyst with a TOF of 100 s1 requires a density of one catalytic site per square nanometer. Catalysts with lower rates or taking up a larger space will require a high-surface-area, nanostructured support that affords tens to hundreds of catalytic sites per square nanometer. Furthermore, catalysts need to operate close to the thermodynamic potential of the redox reaction so that amaximum fraction of the solar photon energy is converted to chemical energy. Stability considerations favor all-inorganic oxide materials, as does avoidance of harsh reaction conditions of pH value or temperature.

Jiao, Feng; Frei, Heinz

2009-01-01T23:59:59.000Z

122

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

SciTech Connect (OSTI)

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

123

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

E-Print Network [OSTI]

and worldwide.1 Consequently, there is an upsurge in the various novel implantable devices to diag- nose- dioverter defibrillator (AICD) and pacemakers. Implantable direct glucose fuel cells (biofuel cells) provide

124

Author's personal copy Reflectance of surfactant-templated mesoporous silica thin films: Simulations  

E-Print Network [OSTI]

-k dielectrics [2­4], photocata- lysis [5], optical materials [2,3,6], thermal insulation [7], optical data validates our simulation tool and offers the prospect of ab-initio design of nanocomposite materials storage [8], corrosion-resistant catalyst supports [9], as well as drug delivery and biosensors [10

Pilon, Laurent

125

A New Class of Highly Dispersed VOx Catalysts on Mesoporous Silica:  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation Desert SouthwestTechnologies |November 2011A First Look atMetal-HydroxideApplication

126

"Multifunctional Mesoporous Silica Catalyst" Patent Awarded | The Ames  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation Desert SouthwestTechnologies | Blandine JeromeX-RayOfficePageof

127

Silica Scaling Removal Process  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administrationcontroller systemsBi (2)Sharing Smart GridShift EndSidneyChemistry » Silica Scaling

128

Organic-inorganic nanocomposite membranes from highly ordered mesoporous thin films for solubility-based separations  

E-Print Network [OSTI]

properties. In this study, we synthesized the organic-inorganic nanocomposite membranes by decorating the surfaces of commercially available mesoporous alumina substrates, and surfactant-templated highly ordered mesoporous silicate thin films placed...

Yoo, Suk Joon

2009-05-15T23:59:59.000Z

129

Bradley S. Lokitz Nanomaterials Synthesis and Functional Assembly  

E-Print Network [OSTI]

Materials Sciences Division Oak Ridge National Laboratory (865) 574-9573 lokitzbs@ornl.gov Publications Materials Sciences, Macromolecular Nanomaterials Group, Oak Ridge National Laboratory, Oak Ridge, TN 2009, Oak Ridge National Laboratory, Oak Ridge, TN, Mentor: S. Michael Kilbey, II Research Emphasis

Pennycook, Steve

130

Large Scale Energy Storage: From Nanomaterials to Large Systems  

E-Print Network [OSTI]

Large Scale Energy Storage: From Nanomaterials to Large Systems Wednesday October 26, 2011, Babbio energy storage devices. Specifically, this talk discusses 1) the challenges for grid scale of emergent technologies with ultralow costs on new energy storage materials and mechanisms. Dr. Jun Liu

Fisher, Frank

131

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

132

Nanocellulose A sustainable nanomaterial derived from wood pulp with  

E-Print Network [OSTI]

Nanocellulose A sustainable nanomaterial derived from wood pulp with applications in composites, sensors, and biomedical devices. The Sustainable Nano-Biocomposites lab in the chemical engineering-renewable resources while offering better performance. #12;Research Program Research in the Sustainable Nano

Thompson, Michael

133

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

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

Influence of adsorption on the diffusion selectivity for mixture permeation across mesoporous membranes  

SciTech Connect (OSTI)

Molecular dynamics (MD) simulations were carried out to determine the self-diffusivities, D{sub 1,self}, and D{sub 2,self} for a variety of binary mixtures: methane (C1)–ethane (C2), C1–propane (C3), C1–n-butane (nC4), C1–n-hexane (nC6), C2–nC4, C2–nC6, Ar–C1, Ar–C2, Ar–C3, Ar–nC4, Ar–nC6, and Ar - Kr in a cylindrical silica mesopores. The diffusion selectivity, defined by (D {sub 1,self}/D {sub 2,self}) was found to be significantly different from the Knudsen selectivity, {radical}M{sub 2}/M{sub 1}, where M {sub I} is the molar mass of species i . For mixtures in which component 2 is more strongly adsorbed than component 1, (D{sub 1,self}/D{sub 2,self})/{radical}M{sub 2}/M{sub 1} has values in the range 1.5–4; the departures from the Knudsen selectivity increased with increasing differences in adsorption strengths of the constituent species.

Krishna, Rajamani; van Baten, Jasper M.

2011-01-01T23:59:59.000Z

136

Water Purification Using Functional Nanomaterials: Sequestering Toxic Heavy Metals  

SciTech Connect (OSTI)

Water, and water quality, are issues of critical importance to the future of humankind. Our water supply has been contaminated by a wide variety of industrial, military and natural sources. There is a serious need for technologies to remove toxic heavy metals and radionuclides from the world’s water supplies. Surfactant templated synthesis of mesoporous ceramics provides a versatile foundation upon which to create high efficiency environmental sorbents. These nanoporous ceramics condense a huge amount of surface area into a very small volume. These mesoporous architectures can be subsequently functionalized through molecular self-assembly. These functional mesoporous materials offer significant capabilities in terms of removal of heavy metals and radionuclides from groundwater and other liquid media. They are highly efficient sorbents, whose interfacial chemistry can be fine-tuned to selectively sequester a specific target species, such as heavy metals, tetrahedral oxometallate anions and radionuclides. Their rigid, open pore structure allows for rapid, efficient sorption kinetics. This manuscript provides an overview of the design, synthesis and performance of the sorbent materials.

Fryxell, Glen E.

2008-02-01T23:59:59.000Z

137

Combustion process for synthesis of carbon nanomaterials from liquid hydrocarbon  

DOE Patents [OSTI]

The present invention provides a combustion apparatus for the production of carbon nanomaterials including fullerenes and fullerenic soot. Most generally the combustion apparatus comprises one or more inlets for introducing an oxygen-containing gas and a hydrocarbon fuel gas in the combustion system such that a flame can be established from the mixed gases, a droplet delivery apparatus for introducing droplets of a liquid hydrocarbon feedstock into the flame, and a collector apparatus for collecting condensable products containing carbon nanomaterials that are generated in the combustion system. The combustion system optionally has a reaction zone downstream of the flame. If this reaction zone is present the hydrocarbon feedstock can be introduced into the flame, the reaction zone or both.

Diener, Michael D.; Alford, J. Michael; Nabity, James; Hitch, Bradley D.

2007-01-02T23:59:59.000Z

138

Mineral mesopore effects on nitrogenous organic matter Andrew R. Zimmermana,  

E-Print Network [OSTI]

as sequestration of pollutants in soils and sediments (Luthy et al., 1997), turnover of natural soil organic carbon that organic matter (OM) may be protected from enzymatic degradation by sequestration within mineral mesopores observations. These results provide a potential mechanism for the selective sequestration and preservation

Chorover, Jon

139

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

140

In Situ Transmission Electron Microscopy Characterization of Nanomaterials  

E-Print Network [OSTI]

on the grain boundary sliding and grain rotation while the grain boundary interacting with dislocations [7-9]. The discoveries of new nanomaterials such as carbon nanotubes, nanowires and graphene have shown large potential impacts in the developments... with nanometer sized width [18]. Next, graphene nanosheet or thin film can be explained as a two dimensional nanostructured material with nanosized thickness [12, 19]. And finally, bulk nanostructed material can be exampled as a three dimensional...

Lee, Joon Hwan 1977-

2012-11-27T23:59:59.000Z

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.


141

Development of Integrated Microanalysis of Nanomaterials (06-ERI-001)  

SciTech Connect (OSTI)

Comets--small extraterrestrial bodies of ice, dust, and small rocky particles--are considered the oldest, most primitive bodies in the solar system. They were thought to be composed of preserved interstellar particles from 4.6 billion years ago, when the Sun and the planets began to form from a primordial disk of dust and gas. The nonvolatile mineral components of comets are probably natural nanomaterials that include preserved interstellar dust as well as the first solids condensed in the solar system. Thus, comet samples may be considered as forensic 'time capsules' from the presolar molecular cloud and the earliest stages of solar system formation. Cometary material was captured in 2004, when the National Aeronautics and Space Administration's Stardust spacecraft flew through the coma of comet Wild as it neared the orbit of Mars. As Stardust approached the 4.5-kilometer-diameter comet, the spacecraft briefly extended a collector filled with lightweight aerogel glass foam to capture thousands of tiny particles. On January 15, 2006, the spacecraft ejected its sample return capsule onto the Utah desert southwest of Salt Lake City. Researchers at LLNL supported by this LDRD were part of a collaborative team investigating the mineralogical, chemical, and isotopic compositions of natural cometary nanomaterials from the Stardust mission using the unique array of analytical facilities at Livermore. The studies have provided provide new insight into cosmically primitive materials that will enable a better understanding of the earliest stages of disk accretion around stars. The skills and analysis techniques developed for the characterization of these natural nanomaterials are synergistic with several Livermore programmatic needs in the emerging fields of nanomaterials, nanotechnology and forensics. The Stardust samples are also ideal training materials for a new generation of young scientists using state-of-the-art analytical instruments at the Laboratory.

Bradley, J P

2009-10-07T23:59:59.000Z

142

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

143

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

144

Stabilized fuel with silica support structure  

SciTech Connect (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

145

Facile fabrication of three-dimensional mesoporous Si/SiC composites via one-step magnesiothermic reduction at relative low temperature  

SciTech Connect (OSTI)

Graphical abstract: - Highlights: • The Si/SiC composites were synthesized by one-step magnesiothermic reduction. • The mesoporous composites have a high specific surface area (655.7 m{sup 2} g{sup ?1}). • The composites exhibited a strong photoluminescence and better biocompatibility. • The mechanisms of formation and photoluminescence of sample were discussed. - Abstract: By converting modified silica aerogels to the corresponding silicon/silicon carbide (Si/SiC) without losing its nanostructure, three-dimensional mesoporous (3DM) Si/SiC composites are successfully synthesized via one-step magnesothermic reduction at relative low temperature (650 °C). The phase composition and microstructure of the resulting samples are measured by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), Raman spectra, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). N{sub 2}-sorption isotherms results show that the products have high Brunauer–Emmett–Teller (BET) specific surface areas (up to 656 m{sup 2} g{sup ?1}) and narrow pore-size distributions (1.5–30 nm). The composites exhibit a strong photoluminescence (PL) in blue-green light region (peak centered at 533 nm). We have set out work on the biocompatibility and enhancing PL of samples. As a result of excellent performances of the composites, it can be expected to have significant application in optoelectronics, biosensors, biological tracer and so on.

Jiang, Zhihang; Ma, Yongjun [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China); Zhou, Yong [Eco-materials and Renewable Energy Research Center (ERERC), School of Physics, National Lab of Solid State Microstructure, ERERC, Nanjing University, Nanjing 210093 (China); Hu, Shanglian [School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010 (China); Han, Chaojiang [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China); Pei, Chonghua, E-mail: peichonghua@swust.edu.cn [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China)

2013-10-15T23:59:59.000Z

146

Structural simulations of nanomaterials self-assembled from ionic macrocycles.  

SciTech Connect (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

147

Nanomaterials for bio-functionalized electrodes: recent trends  

SciTech Connect (OSTI)

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

148

Pore-structure determinations of silica aerogels by {sup 129}Xe NMR spectroscopy and imaging.  

SciTech Connect (OSTI)

Silica aerogels represent a new class of open-pore materials with pore dimensions on a scale of tens of nanometers, and are thus classified as mesoporous materials. In this work, we show that the combination of NMR spectroscopy and chemical-shift selective magnetic resonance imaging (MRI) can resolve some of the important aspects of the structure of silica aerogels. The use of xenon as a gaseous probe in combination with spatially resolved NMR techniques is demonstrated to be a powerful, new approach for characterizing the average pore structure and steady-state spatial distributions of xenon atoms in different physicochemical environments. Furthermore, dynamic NMR magnetization transfer experiments and pulsed-field gradient (PFG) measurements have been used to characterize exchange processes and diffusive motion of xenon in samples at equilibrium. In particular, this new NMR approach offers unique information and insights into the nanoscopic pore structure and microscopic morphology of aerogels and the dynamical behavior of occluded adsorbates. MRI provides spatially resolved information on the nature of the flaw regions found in these materials. Pseudo-first-order rate constants for magnetization transfer among the bulk and occluded xenon phases indicate xenon-exchange rate constants on the order of 1 s-1 for specimens having volumes of 0.03 cm3. PFG diffusion measurements show evidence of anisotropic diffusion for xenon occluded within aerogels, with nominal self-diffusivity coefficients on the order of D= 10-3cm2/s.

Gregory, D. M.; Gerald, R. E., II; Botto, R. E.; Chemistry

1998-04-01T23:59:59.000Z

149

ccsd-00000575(version1):3Sep2003 Intrusion and extrusion of water in hydrophobic mesopores  

E-Print Network [OSTI]

isotherms and capillary conden- sation, usually described as a gas-liquid phase transition shiftedccsd-00000575(version1):3Sep2003 Intrusion and extrusion of water in hydrophobic mesopores B- extrusion cycles of water in hydrophobic mesoporous materials, characterized by independent cylindrical

Boyer, Edmond

150

Three-Dimensional Coherent Titania-Mesoporous Carbon Nanocomposite and Its Lithium-Ion Storage Properties  

E-Print Network [OSTI]

Three-Dimensional Coherent Titania-Mesoporous Carbon Nanocomposite and Its Lithium-Ion Storage Properties Laifa Shen,, Evan Uchaker, Changzhou Yuan, Ping Nie, Ming Zhang, Xiaogang Zhang,*, and Guozhong into the channels of surface- oxidized mesoporous carbon (CMK-3) by means of electrostatic interaction, followed

Cao, Guozhong

151

Studies on Supercapacitor Electrode Material from Activated Lignin-Derived Mesoporous Carbon  

SciTech Connect (OSTI)

We synthesized mesoporous carbon from pre-cross-linked lignin gel impregnated with a surfactant as the pore-forming agent, and then activated the carbon through physical and chemical methods to obtain activated mesoporous carbon. The activated mesoporous carbons exhibited 1.5- to 6-fold increases in porosity with a maximum BET specific surface area of 1148 m2/g and a pore volume of 1.0 cm3/g. Slow physical activation helped retain dominant mesoporosity; however, aggressive chemical activation caused some loss of the mesopore volume fraction. Plots of cyclic voltammetric data with the capacitor electrode made from these carbons showed an almost rectangular curve depicting the behavior of ideal double-layer capacitance. Although the pristine mesoporous carbon exhibited the same range of surface-area-based capacitance as that of other known carbon-based supercapacitors, activation decreased the surface-area-based specific capacitance and increased the gravimetric-specific capacitance of the mesoporous carbons. Surface activation lowered bulk density and electrical conductivity. Warburg impedance as a vertical tail in the lower frequency domain of Nyquist plots supported good supercapacitor behavior for the activated mesoporous carbons. Our work demonstrated that biomass-derived mesoporous carbon materials continue to show potential for use in specific electrochemical applications.

Saha, Dipendu [ORNL] [ORNL; Li, Yunchao [ORNL] [ORNL; Bi, Zhonghe [ORNL] [ORNL; Chen, Jihua [ORNL] [ORNL; Keum, Jong Kahk [ORNL] [ORNL; Hensley, Dale K [ORNL] [ORNL; Grappe, Hippolyte A. [Oak Ridge Institute for Science and Education (ORISE)] [Oak Ridge Institute for Science and Education (ORISE); Meyer III, Harry M [ORNL] [ORNL; Dai, Sheng [ORNL] [ORNL; Paranthaman, Mariappan Parans [ORNL] [ORNL; Naskar, Amit K [ORNL] [ORNL

2014-01-01T23:59:59.000Z

152

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

153

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

154

Mesoporous metal oxide microsphere electrode compositions and their methods of making  

SciTech Connect (OSTI)

Compositions and methods of making are provided for treated mesoporous metal oxide microspheres electrodes. The compositions comprise (a) microspheres with an average diameter between 200 nanometers (nm) and 10 micrometers (.mu.m); (b) mesopores on the surface and interior of the microspheres, wherein the mesopores have an average diameter between 1 nm and 50 nm and the microspheres have a surface area between 50 m.sup.2/g and 500 m.sup.2/g, and wherein the composition has an electrical conductivity of at least 1.times.10.sup.-7 S/cm at 25.degree. C. and 60 MPa. The methods of making comprise forming a mesoporous metal oxide microsphere composition and treating the mesoporous metal oxide microspheres by at least one method selected from the group consisting of: (i) annealing in a reducing atmosphere, (ii) doping with an aliovalent element, and (iii) coating with a coating composition.

Parans Paranthaman, Mariappan; Bi, Zhonghe; Bridges, Craig A; Brown, Gilbert M

2014-12-16T23:59:59.000Z

155

Silica Supported Ceria Nanoparticles: A Hybrid Nanostructure...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

The surface chemical and vibrational spectroscopy analysis revealed cerium–silicate (Ce-O-Si) covalent bond linkage between silica and cerium oxide nanoparticles. The...

156

1 AQUEOUS SILICA POLYMERIZATION IN Silica polymers have long been recognized in aque-  

E-Print Network [OSTI]

1 AQUEOUS SILICA POLYMERIZATION IN PURE H2O Silica polymers have long been recognized in aque- ous is accompanied by increased extent of polymerization. Silica concentrations in equilibrium with quartz. In the system SiO2-H2O, the structure of supercritical hy- drous SiO2 melt is strongly polymerized at

Manning, Craig

157

Advanced Nanomaterials for High-Efficiency Solar Cells  

SciTech Connect (OSTI)

Energy supply has arguably become one of the most important problems facing humankind. The exponential demand for energy is evidenced by dwindling fossil fuel supplies and record-high oil and gas prices due to global population growth and economic development. This energy shortage has significant implications to the future of our society, in addition to the greenhouse gas emission burden due to consumption of fossil fuels. Solar energy seems to be the most viable choice to meet our clean energy demand given its large scale and clean/renewable nature. However, existing methods to convert sun light into electricity are not efficient enough to become a practical alternative to fossil fuels. This DOE project aims to develop advanced hybrid nanomaterials consisting of semiconductor nanoparticles (quantum dots or QDs) supported on graphene for cost-effective solar cells with improved conversion efficiency for harvesting abundant, renewable, clean solar energy to relieve our global energy challenge. Expected outcomes of the project include new methods for low-cost manufacturing of hybrid nanostructures, systematic understanding of their properties that can be tailored for desired applications, and novel photovoltaic cells. Through this project, we have successfully synthesized a number of novel nanomaterials, including vertically-oriented graphene (VG) sheets, three-dimensional (3D) carbon nanostructures comprising few-layer graphene (FLG) sheets inherently connected with CNTs through sp{sup 2} carbons, crumpled graphene (CG)-nanocrystal hybrids, CdSe nanoparticles (NPs), CdS NPs, nanohybrids of metal nitride decorated on nitrogen-doped graphene (NG), QD-carbon nanotube (CNT) and QD-VG-CNT structures, TiO{sub 2}-CdS NPs, and reduced graphene oxide (RGO)-SnO{sub 2} NPs. We further assembled CdSe NPs onto graphene sheets and investigated physical and electronic interactions between CdSe NPs and the graphene. Finally we have demonstrated various applications of these nanomaterials in solar cells (both as photoanodes and counter electrodes), gas sensors, and energy storage devices. This research is potentially transformative since the availability of affordable hybrid nanostructures and their fundamental properties will enable various innovative applications of the multifunctional hybrid nanostructures and thus will accelerate new discoveries and inventions in nanoscience and nanotechnology.

Chen, Junhong [University of Wisconsin-Milwaukee] [University of Wisconsin-Milwaukee

2013-11-29T23:59:59.000Z

158

Silica Geothermometers | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home5b9fcbce19 No revisionEnvReviewNonInvasiveExplorationUT-g Grant ofRichardton AbbeyARaftPadomaSierra Leone)Sikes Act JumpSilica

159

Synthesis of supported carbon nanotubes in mineralized silica...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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

160

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

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

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

162

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

163

Surface chemistry of mesoporous materials : effect of nanopore confinement.  

SciTech Connect (OSTI)

Acid-base titration and metal sorption experiments were performed on both mesoporous alumina and alumina particles under various ionic strengths. It has been demonstrated that surface chemistry and ion sorption within nanopores can be significantly modified by a nano-scale space confinement. As the pore size is reduced to a few nanometers, the difference between surface acidity constants (pK2 - pK1) decreases, giving rise to a higher surface charge density on a nanopore surface than that on an unconfined solid-solution interface. The change in surface acidity constants results in a shift of ion sorption edges and enhances ion sorption on that nanopore surfaces.

Wang, Yifeng (Sandia National Laboratories, Carlsbad, NM); Bryan, Charles R. (Sandia National Laboratories, Carlsbad, NM); Xu, Huifang (University of New Mexico, Albuquerque, NM); Gao, Huizhen (Sandia National Laboratories, Carlsbad, NM)

2003-03-01T23:59:59.000Z

164

Surface Reductive Capacity of Carbon Nanomaterials after Various Heating and Aging Processes  

E-Print Network [OSTI]

Understanding the toxicity of carbon nanomaterials, such as carbon nanotubes and graphenes, is important for the development of nanotechnology. Studies have shown that surface redox capability is an important factor for toxicity of carbon...

Lee, Chunghoon

2012-10-19T23:59:59.000Z

165

Simple Chemical Routes for Changing Composition or Morphology in Metal Chalcogenide Nanomaterials  

E-Print Network [OSTI]

Metal chalcogenide nanomaterials are interesting due to their size dependent properties and potential use in numerous types of devices or applications. The synthetic methods of binary phase metal chalcogenide nanoparticles are well established...

Wark, Stacey Elaine

2012-07-16T23:59:59.000Z

166

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

167

Insight into Proton Transfer in Phosphotungstic Acid Functionalized Mesoporous Silica-Based Proton Exchange Membrane Fuel Cells  

E-Print Network [OSTI]

University, Perth, Western Australia 6102, Australia Materials and Process Simulation Center, California 138632, Singapore § Fuels and Energy Technology Institute & Department of Chemical Engineering, Curtin humidity (RH) with a low activation energy of 14 kJ mol-1 . In order to determine the energetics associated

Goddard III, William A.

168

Hollow silica and silica-boron nano/microparticles for contrast-enhanced ultrasound to detect small tumors  

E-Print Network [OSTI]

Hollow silica and silica-boron nano/microparticles for contrast-enhanced ultrasound to detect small Accepted 18 March 2012 Available online 11 April 2012 Keywords: Ultrasound Nano Silica Shells Imaging detection, gas filled hollow boron-doped silica particles have been developed, which can be used

Kummel, Andrew C.

169

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

170

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

E-Print Network [OSTI]

??This study focuses on hybrid aerogels of syndiotactic polystyrene (sPS) and silica where silica concentration is varied and silica condensation conditions are varied to produce… (more)

Zhang, Huan

2014-01-01T23:59:59.000Z

171

An overview—Functional nanomaterials for lithium rechargeable batteries, supercapacitors, hydrogen storage, and fuel cells  

SciTech Connect (OSTI)

Graphical abstract: Nanomaterials play important role in lithium ion batteries, supercapacitors, hydrogen storage and fuel cells. - Highlights: • Nanomaterials play important role for lithium rechargeable batteries. • Nanostructured materials increase the capacitance of supercapacitors. • Nanostructure improves the hydrogenation/dehydrogenation of hydrogen storage materials. • Nanomaterials enhance the electrocatalytic activity of the catalysts in fuel cells. - Abstract: There is tremendous worldwide interest in functional nanostructured materials, which are the advanced nanotechnology materials with internal or external dimensions on the order of nanometers. Their extremely small dimensions make these materials unique and promising for clean energy applications such as lithium ion batteries, supercapacitors, hydrogen storage, fuel cells, and other applications. This paper will highlight the development of new approaches to study the relationships between the structure and the physical, chemical, and electrochemical properties of functional nanostructured materials. The Energy Materials Research Programme at the Institute for Superconducting and Electronic Materials, the University of Wollongong, has been focused on the synthesis, characterization, and applications of functional nanomaterials, including nanoparticles, nanotubes, nanowires, nanoporous materials, and nanocomposites. The emphases are placed on advanced nanotechnology, design, and control of the composition, morphology, nanostructure, and functionality of the nanomaterials, and on the subsequent applications of these materials to areas including lithium ion batteries, supercapacitors, hydrogen storage, and fuel cells.

Liu, Hua Kun, E-mail: hua@uow.edu.au

2013-12-15T23:59:59.000Z

172

Macro-ions collapse leading to hybrid bio-nanomaterials.  

SciTech Connect (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

173

Assembly and actuation of nanomaterials using active biomolecules.  

SciTech Connect (OSTI)

The formation and functions of living materials and organisms are fundamentally different from those of synthetic materials and devices. Synthetic materials tend to have static structures, and are not capable of adapting to the functional needs of changing environments. In contrast, living systems utilize energy to create, heal, reconfigure, and dismantle materials in a dynamic, non-equilibrium fashion. The overall goal of the project was to organize and reconfigure functional assemblies of nanoparticles using strategies that mimic those found in living systems. Active assembly of nanostructures was studied using active biomolecules to drive the organization and assembly of nanocomposite materials. In this system, kinesin motor proteins and microtubules were used to direct the transport and interactions of nanoparticles at synthetic interfaces. In addition, the kinesin/microtubule transport system was used to actively assemble nanocomposite materials capable of storing significant elastic energy. Novel biophysical measurement tools were also developed for measuring the collective force generated by kinesin motor proteins, which will provide insight on the mechanical constraints of active assembly processes. Responsive reconfiguration of nanostructures was studied in terms of using active biomolecules to mediate the optical properties of quantum dot (QD) arrays through modulation of inter-particle spacing and associated energy transfer interaction. Design rules for kinesin-based transport of a wide range of nanoscale cargo (e.g., nanocrystal quantum dots, micron-sized polymer spheres) were developed. Three-dimensional microtubule organizing centers were assembled in which the polar orientation of the microtubules was controlled by a multi-staged assembly process. Overall, a number of enabling technologies were developed over the course of this project, and will drive the exploitation of energy-driven processes to regulate the assembly, disassembly, and dynamic reorganization of nanomaterials.

Spoerke, Erik David; Thayer, Gayle Echo; de Boer, Maarten Pieter; Bunker, Bruce Conrad; Liu, Jun; Corwin, Alex David; Gaudioso, Jennifer Marie; Sasaki, Darryl Yoshio; Boal, Andrew Kiskadden; Bachand, George David; Trent, Amanda M.; Bachand, Marlene; Rivera, Susan B.; Koch, Steven John

2005-11-01T23:59:59.000Z

174

The Management of Silica in Los Alamos National Laboratory Tap Water - A Study of Silica Solubility  

SciTech Connect (OSTI)

Well water at Los Alamos National Laboratory (LANL) has a silica (SiO{sub 2}) content of 60 to 100 mg/L, with 4 mg/L of magnesium, 13 mg/L calcium and lesser concentrations of other ions. On evaporation in cooling towers, when the silica concentration reaches 150 to 220 mg/L, silica deposits on heat transfer surfaces. When the high silica well water is used in the reprocessing of plutonium, silica remains in solution at the end of the process and creates a problem of removal from the effluent prior to discharge or evaporation. The work described in this Report is divided into two major parts. The first part describes the behavior of silica when the water is evaporated at various conditions of pH and in the presence of different classes of anions: inorganic and organic. In the second part of this work it was found that precipitation (floccing) of silica was a function of solution pH and mole ratio of metal to silica.

Wohlberg, C.; Worland, V.P.; Kozubal, M.A.; Erickson, G.F.; Jacobson, H.M.; McCarthy, K.T.

1999-07-01T23:59:59.000Z

175

A New Concept for the Fabrication of Hydrogen Selective Silica Membranes  

SciTech Connect (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

176

1Plastic deformation and fracture processes in metallic and ceramic nanomaterials... 2007 Advanced Study Center Co. Ltd.  

E-Print Network [OSTI]

1Plastic deformation and fracture processes in metallic and ceramic nanomaterials... © 2007-mail: ovidko@def.ipme.ru PLASTIC DEFORMATION AND FRACTURE PROCESSES IN METALLIC AND CERAMIC NANOMATERIALS at the boundaries between the large grains and nanoscale matrix. In the framework of the model, cracks are generated

Ovid'ko Ilya A.

177

E-Print Network 3.0 - alumina silica-alumina etude Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

14 (2004) 681686 PII: S0960-1317(04)71691-5 Summary: for silica, alumina, and titania aerogels. Silica and alumina aerogel cantilevers are fabricated on the basis... Silica Silica...

178

High resolution patterning of silica aerogels  

SciTech Connect (OSTI)

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

179

PMo or PW heteropoly acids supported on MCM-41 silica nanoparticles: Characterisation and FT-IR study of the adsorption of 2-butanol  

SciTech Connect (OSTI)

Mesoporous silica, prepared in basic conditions, has been loaded (20% weight) with 12-molybdophosphoric (PMo) or 12-tungstophosphoric (PW) acid and calcined at different temperatures ranging between 250 and 550 deg. C. The samples have been characterised by N{sub 2} adsorption-desorption at -196 deg. C, transmission electron microscopy (TEM), powder X-ray diffraction (PXRD), UV-visible diffuse reflectance, Raman spectroscopy and temperature programmed reduction (TPR). The acidity and catalytic activity have been, respectively, examined by monitoring the adsorption of pyridine and 2-butanol by FT-IR spectroscopy. The results indicate that PW and PMo acids are highly dispersed on mesoporous silica MCM-41 spherical nanoparticles. While PMo retains its Keggin structure up to 550 deg. C, PW decomposes at this temperature into crystalline WO{sub 3} and phosphorous oxides. In both cases, the morphology, hexagonal symmetry and long-range order observed for the support are preserved with calcination up to 450 deg. C. The Broensted-type acid sites found in all samples, whose surface concentration decreases as the calcination temperature increases, are responsible for the selective formation of cis-butene detected upon adsorption of 2-butanol. The sample containing PW calcined at 450 deg. C also shows selectivity to methyl ethyl ketone. - Graphical abstract: Samples based in MCM-41 nanoparticles loaded with tungstophosphoric and molybdophosphoric acids have been synthesised. The uncalcined solids and that derived upon their calcination in the temperature range 250-550 deg. C have been characterised and evaluated in the decomposition of 2-butanol monitored by FT-IR spectroscopy.

Carriazo, Daniel [GIR-QUESCAT, Dpto. de Quimica Inorganica, Universidad de Salamanca, 37008-Salamanca (Spain); Domingo, Concepcion [Instituto de Estructura de la Materia, C.S.I.C., Serrano, 123, 28006-Madrid (Spain); Martin, Cristina [GIR-QUESCAT, Dpto. de Quimica Inorganica, Universidad de Salamanca, 37008-Salamanca (Spain); Rives, Vicente [GIR-QUESCAT, Dpto. de Quimica Inorganica, Universidad de Salamanca, 37008-Salamanca (Spain)], E-mail: vrives@usal.es

2008-08-15T23:59:59.000Z

180

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

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

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

182

Hierarchical mesoporous/microporous carbon with graphitized frameworks for high-performance lithium-ion batteries  

SciTech Connect (OSTI)

A hierarchical meso-/micro-porous graphitized carbon with uniform mesopores and ordered micropores, graphitized frameworks, and extra-high surface area of ?2200 m{sup 2}/g, was successfully synthesized through a simple one-step chemical vapor deposition process. The commercial mesoporous zeolite Y was utilized as a meso-/ micro-porous template, and the small-molecule methane was employed as a carbon precursor. The as-prepared hierarchical meso-/micro-porous carbons have homogeneously distributed mesopores as a host for electrolyte, which facilitate Li{sup +} ions transport to the large-area micropores, resulting a high reversible lithium ion storage of 1000 mA h/g and a high columbic efficiency of 65% at the first cycle.

Lv, Yingying; Fang, Yin; Qian, Xufang; Tu, Bo [Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Laboratory of Advanced Materials, Fudan University, Shanghai 200433 (China); Wu, Zhangxiong [Department of Chemical Engineering, Monash University, Clayton, VIC 3800 (Australia); Asiri, Abdullah M. [Chemistry Department and The Center of Excellence for Advanced Materials Research, King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia); Zhao, Dongyuan, E-mail: dyzhao@fudan.edu.cn [Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Laboratory of Advanced Materials, Fudan University, Shanghai 200433 (China); Department of Chemical Engineering, Monash University, Clayton, VIC 3800 (Australia)

2014-11-01T23:59:59.000Z

183

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

184

Mesoporous Carbon for Capacitive Deionization of Saline Water  

SciTech Connect (OSTI)

Self-assembled mesoporous carbon (MC) materials have been synthesized and tested for application in capacitive deionization (CDI) of saline water. MC was prepared by self-assembly of a triblock copolymer with hydrogen-bonded chains via a phenolic resin, such as resorcinol or phloroglucinol in acidic conditions, followed by carbonization and, in some cases, activation by KOH. Carbon synthesized in this way was ground into powder, from which activated MC sheets were produced. In a variation of this process, after the reaction of triblock copolymer with resorcinol or phloroglucinol, the gel that was formed was used to coat a graphite plate and then carbonized. The coated graphite plate in this case was not activated and was tested to serve as current collector during the CDI process. The performance of these MC materials was compared to that of carbon aerogel for salt concentrations ranging between 1000 ppm and 35,000 ppm. Resorcinol-based MC removed up to 15.2 mg salt per gram of carbon, while carbon aerogel removed 5.8 mg salt per gram of carbon. Phloroglucinol-based MC-coated graphite exhibited the highest ion removal capacity at 21 mg of salt per gram of carbon for 35,000 ppm salt concentration.

Tsouris, Costas [ORNL; Mayes, Richard T [ORNL; Kiggans, Jim [ORNL; Sharma, Ms. Ketki [Georgia Institute of Technology; Yiacoumi, Sotira [Georgia Institute of Technology; DePaoli, David W [ORNL; Dai, Sheng [ORNL

2011-01-01T23:59:59.000Z

185

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

186

Nanomaterials-Enabled Dye-Sensitized Solar Cells and Jun Lou1  

E-Print Network [OSTI]

O-7 Nanomaterials-Enabled Dye-Sensitized Solar Cells Pei Dong1 and Jun Lou1 1 sensitized solar cells (DSCs), the third generation of solar cells, have attracted more and more attention Department of Mechanical Engineering and Materials Science, Rice University, Houston, Texas, U.S.A. Dye

187

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

SciTech Connect (OSTI)

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

188

Identifying Optimal Inorganic Nanomaterials for Hybrid Solar Cells Hongjun Xiang* and Su-Huai Wei  

E-Print Network [OSTI]

Identifying Optimal Inorganic Nanomaterials for Hybrid Solar Cells Hongjun Xiang* and Su-Huai Wei and Department of Physics, Fudan UniVersity, Shanghai 200433, China ReceiVed: August 17, 2009 As a newly developed photovoltaic technology, organic-inorganic hybrid solar cells have attracted great interest

Gong, Xingao

189

NANOMATERIALS FOR HIGH CAPACITY LI-ION BATTERIES Taylor Grieve, Iowa State University, SURF 2009 Fellow  

E-Print Network [OSTI]

NANOMATERIALS FOR HIGH CAPACITY LI-ION BATTERIES Taylor Grieve, Iowa State University, SURF 2009 energy storage devices continues to grow. Lithium-ion (Li-ion) secondary, or renewable, batteries are of interest due to their high energy and power characteristics. Performance enhancements of Li- ion batteries

Li, Mo

190

Progress in Crystal Growth & Characterization of Materials 2007 Raman Spectroscopy of Nanomaterials: How Spectra  

E-Print Network [OSTI]

the experimental versatility of µRS applied to nanomaterials (phase identification, phase transition monitoring: pigments for the cosmetic industry (metal-oxides), fluorescent markers (quantum dots), photonic crystals. Mechanics: cutting tools, wear-resistant and anti-corrosion coatings (cemented carbides), "nano

Paris-Sud XI, Université de

191

Laser Interactions in Nanomaterials Synthesis David B. Geohegan1,2  

E-Print Network [OSTI]

Laser Interactions in Nanomaterials Synthesis David B. Geohegan1,2 , Alex A. Puretzky1,2 , Chris. Laser interactions with materials have unique advantages to explore the rapid synthesis, processing, laser vaporization of solids into background gases provides a wide range of processing conditions

Pennycook, Steve

192

Uranium and Strontium Batch Sorption and Diffusion Kinetics into Mesoporous  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLasDelivered energy consumption by sectorlongUpdates by Diane Johnson9. Foreignb.UnderSilica |

193

Anisotropic Hexagonal Boron Nitride Nanomaterials - Synthesis and Applications  

SciTech Connect (OSTI)

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

194

Catalysis over activated high silica zeolites  

SciTech Connect (OSTI)

A process is provided for conducting organic compound conversion over a catalyst composition comprising a crystalline zeolite having a high initial silica-to-alumina mole ratio, said zeolite being prepared by calcining the zeolite, contacting said calcined zeolite with solid aluminum fluoride, and coverting said aluminum fluoride contacted material to hydrogen form.

Chang, C. D.; Miale, N.

1985-07-23T23:59:59.000Z

195

Chemistry of Silica in Cerro Prieto Brines  

E-Print Network [OSTI]

1975). When operated without sludge r e c i r c u l a t i ot o c o l l o i d a l silica. sludge accumulation there. thel a t i o n of part of the sludge coming out of The l a r g

Weres, Oleh

2012-01-01T23:59:59.000Z

196

Chemistry of Silica in Cerro Prieto Brines  

E-Print Network [OSTI]

1975). When operated without sludge r e c i r c u l a t i ot o c o l l o i d a l silica. sludge accumulation there. thel a t i o n of part of the sludge coming out of The l a r g

Weres, O.

2010-01-01T23:59:59.000Z

197

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

198

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

199

Effect of diffuse layer and pore shapes in mesoporous carbon supercapacitors  

SciTech Connect (OSTI)

In the spirit of the theoretical evolution from the Helmholtz model to the Gouy Chapman Stern model for electric double-layer capacitors, we explored the effect of a diffuse layer on the capacitance of mesoporous carbon supercapacitors by solving the Poisson Boltzmann (PB) equation in mesopores of diameters from 2 to 20 nm. To evaluate the effect of pore shape, both slit and cylindrical pores were considered. We found that the diffuse layer does not affect the capacitance significantly. For slit pores, the area-normalized capacitance is nearly independent of pore size, which is not experimentally observed for template carbons. In comparison, for cylindrical pores, PB simulations produce a trend of slightly increasing area-normalized capacitance with pore size, similar to that depicted by the electric double-cylinder capacitor model proposed earlier. These results indicate that it is appropriate to approximate the pore shape of mesoporous carbons as being cylindrical and the electric double-cylinder capacitor model should be used for mesoporous carbons as a replacement of the traditional Helmholtz model.

Huang, Jingsong [ORNL; Sumpter, Bobby G [ORNL; Meunier, Vincent [ORNL; Qiao, Rui [ORNL

2010-01-01T23:59:59.000Z

200

Infiltrating Semiconducting Polymers into Self-Assembled Mesoporous Titania Films for Photovoltaic Applications**  

E-Print Network [OSTI]

Infiltrating Semiconducting Polymers into Self-Assembled Mesoporous Titania Films for Photovoltaic. Introduction A promising approach for making inexpensive photovoltaic cells is to fill nanoporous titania films there have been several reports on photovoltaic cells made in this way, there have been no studies that show

McGehee, Michael

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

The adsorption of gold, palladium and platinum from acidic chloride solutions on mesoporous carbons.  

SciTech Connect (OSTI)

Studies on the adsorption characteristics of gold, palladium and platinum on mesoporous carbon (CMK-3) and sulfur-impregnated mesoporous carbon (CMK-3/S) evaluated the benefits/drawbacks of the presence of a layer of elemental sulfur inside mesoporous carbon structures. Adsorption isotherms collected for Au(III), Pd(II) and Pt(IV) on those materials suggest that sulfur does enhance the adsorption of those metal ions in mildly acidic environment (pH 3). The isotherms collected in 1 M HCl show that the benefit of sulfur disappears due to the competing influence of large concentration of hydrogen ions on the ion-exchanging mechanism of metal ions sorption on mesoporous carbon surfaces. The collected acid dependencies illustrate similar adsorption characteristics for CMK-3 and CMK-3/S in 1-5 M HCl concentration range. Sorption of metal ions from diluted aqueous acidic mixtures of actual leached electronic waste demonstrated the feasibility of recovery of gold from such liquors.

Peter Zalupski; Rocklan McDowell; Guy Dutech

2014-10-01T23:59:59.000Z

202

Simulating Electric Double Layer Capacitance of Mesoporous Electrodes with Cylindrical Pores  

E-Print Network [OSTI]

morphology on the capacitance of electric double layer capacitors (EDLCs) made of mesoporous electrodes affecting EDLCs' performance. The simulations showed that reducing the ion effective diameter and the pore capacitors (EDLCs) are energy storage devices that store electric charge in the electric dou- ble layer

Pilon, Laurent

203

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

E-Print Network [OSTI]

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...

Jung, Seunghwan

2012-07-16T23:59:59.000Z

204

Fabrication of hollow mesoporous NiO hexagonal microspheres via hydrothermal process in ionic liquid  

SciTech Connect (OSTI)

Highlights: Black-Right-Pointing-Pointer Ni(OH){sub 2} precursors were synthesized in ionic liquid and water solution by hydrothermal method. Black-Right-Pointing-Pointer NiO hollow microspheres were prepared by thermal treatment of Ni(OH){sub 2} precursors. Black-Right-Pointing-Pointer NiO hollow microspheres were self-assembled by mesoporous cubic and hexagonal nanocrystals with high specific surface area. Black-Right-Pointing-Pointer The mesoporous structure is stable at 773 K. Black-Right-Pointing-Pointer The ionic liquid absorbed on the O-terminate surface of the crystals to form hydrogen bond and played key roles in determining the final shape of the NiO novel microstructure. -- Abstract: The novel NiO hexagonal hollow microspheres have been successfully prepared by annealing Ni(OH){sub 2}, which was synthesized via an ionic liquid-assisted hydrothermal method. The samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), transmission electron microscopy (TEM), N{sub 2} adsorption-desorption and Fourier transform infrared spectrometer (FTIR). The results show that the hollow NiO microstructures are self-organized by mesoporous cubic and hexagonal nanocrystals. The mesoporous structure possessed good thermal stability and high specific surface area (ca. 83 m{sup 2}/g). The ionic liquid 1-butyl-3methylimidazolium tetrafluoroborate ([Bmim][BF{sub 4}]) was found to play a key role in controlling the morphology of NiO microstructures during the hydrothermal process. The special hollow mesoporous architectures will have potential applications in many fields, such as catalysts, absorbents, sensors, drug-delivery carriers, acoustic insulators and supercapacitors.

Zhao, Jinbo, E-mail: zhaojinb@gmail.com [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, 250061, Jinan (China) [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, 250061, Jinan (China); School of Materials Science and Engineering, Shandong University, 250061, Jinan (China); Wu, Lili, E-mail: wulili@sdu.edu.cn [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, 250061, Jinan (China) [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, 250061, Jinan (China); School of Materials Science and Engineering, Shandong University, 250061, Jinan (China); Zou, Ke, E-mail: zouk2005@163.com [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, 250061, Jinan (China) [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, 250061, Jinan (China); School of Materials Science and Engineering, Shandong University, 250061, Jinan (China)

2011-12-15T23:59:59.000Z

205

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

SciTech Connect (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

206

Tubular structured hierarchical mesoporous titania material derived from natural cellulosic substances and application as photocatalyst for degradation of methylene blue  

SciTech Connect (OSTI)

Graphical abstract: Bio-inspired, tubular structured hierarchical mesoporous titania material with high photocatalytic activity under UV light was fabricated employing natural cellulosic substance (cotton) as hard template and cetyltrimethylammonium bromide (CTAB) surfactant as soft template using a one-pot sol-gel method. Highlights: {yields} Tubular structured mesoporous titania material was fabricated by sol-gel method. {yields} The titania material faithfully recorded the hierarchical structure of the template substrate (cotton). {yields} The titania material exhibited high photocatalytic activity in decomposition of methylene blue. -- Abstract: Bio-inspired, tubular structured hierarchical mesoporous titania material was designed and fabricated employing natural cellulosic substance (cotton) as hard template and cetyltrimethylammonium bromide (CTAB) surfactant as soft template by one-pot sol-gel method. The tubular structured hierarchical mesoporous titania material processes large specific surface area (40.23 m{sup 2}/g) and shows high photocatalytic activity in the photodegradation of methylene blue under UV light irradiation.

Huang, Haiqing [Key Laboratory of Radioactive Geology and Exploration Technology Fundamental Science for National Defense, East China Institute of Technology, Fuzhou, Jiangxi 344000 (China)] [Key Laboratory of Radioactive Geology and Exploration Technology Fundamental Science for National Defense, East China Institute of Technology, Fuzhou, Jiangxi 344000 (China); Liu, Xiaoyan [Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027 (China)] [Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027 (China); Huang, Jianguo, E-mail: jghuang@zju.edu.cn [Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027 (China)] [Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027 (China)

2011-11-15T23:59:59.000Z

207

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

SciTech Connect (OSTI)

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

208

3D Corporate Tourism: A Concept for Innovation in Nanomaterials Engineering  

E-Print Network [OSTI]

Nature's materials are complex, multifunctional, hierarchical and responsive and in most instances functionality on the nanoscale is combined with performance on the macroscale. Materials engineers have just started to produce complex nanomaterials. Biomimicry and biomimetics deal with knowledge transfer from nature to technology. Inspired by the 'Biomimicry and Design Workshops' and the 'Biomimicry Innovation Method' by the US based Biomimicry Guild, '3D Corporate Tourism', a solution based approach to innovation in nanomaterials research, is proposed. The three main pillars of this integrated concept are discover, develop and design. Biologists, research and development engineers as well as designers jointly work in an environment with high inspirational potential and construct first prototypes and designs on site. This joint approach yields new links, networks and collaborations between communities of thinkers in different countries in order to stimulate and enhance creative and application oriented proble...

Gebeshuber, I C

2010-01-01T23:59:59.000Z

209

Light-scattering studies of silica aerogels  

SciTech Connect (OSTI)

Due to its combination of transparency and low thermal conductivity, aerogel holds considerable promise for use as insulating window materials for residential and commercial applications. This paper reports on the preliminary investigation of the optical and scattering properties of silica aerogels. It briefly describes the properties of aerogels important for window glazing applications. The optical properties are then described, followed by a discussion of the scattering measurements and their interpretation.

Hunt, A.J.

1983-02-01T23:59:59.000Z

210

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.

Makoto Tabata; Ichiro Adachi; Hideyuki Kawai; Masato Kubo; Takeshi Sato

2012-03-19T23:59:59.000Z

211

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

212

Novel silica-based ion exchange resin  

SciTech Connect (OSTI)

Eichrom`s highly successful Diphonixo resin resembles a conventional ion exchange resin in its use of sulfonic acid ligands on a styrene- divinylbenzene matrix. Diphonix resin exhibits rapid exchange kinetics that allow economical operation of ion exchange systems. Unlike conventional resins, Diphonix resin contains chelating ligands that are diphosphonic acid groups that recognize and remove the targeted metals and reject the more common elements such as sodium, calcium and magnesium. This latter property makes Diphonix ideal for many industrial scale applications, including those involving waste treatment. For treatment of low-level, transuranic (TRU) and high- level radioactive wastes, Diphonix`s polystyrene backbone hinders its application due to radiolytic stability of the carbon-hydrogen bonds and lack of compatibility with expected vitrification schemes. Polystyrene-based Diphonix is approximately 60% carbon- hydrogen. In response to an identified need within the Department of Energy for a resin with the positive attributes of Diphonix that also exhibits greater radiolytic stability and final waste form compatibility, Eichrom has successfully developed a new, silica-based resin version of Diphonix. Target application for this new resin is for use in environmental restoration and waste management situations involving the processing of low-level, transuranic and high-level radioactive wastes. The resin can also be used for processing liquid mixed waste (waste that contains low level radioactivity and hazardous constituents) including mixed wastes contaminated with organic compounds. Silica-based Diphonix is only 10% carbon-hydrogen, with the bulk of the matrix silica.

NONE

1997-11-01T23:59:59.000Z

213

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

SciTech Connect (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

214

Cr, N-Codoped TiO2 Mesoporous Microspheres for Li-ion Rechargeable Batteries with Enhanced Electrochemical Performance  

SciTech Connect (OSTI)

Cr,N-codoped TiO2 mesoporous microspheres synthesized using hydrothermal and subsequent nitridation treatment, exhibited higher solubility of nitrogen, and improved electrical conductivity than N-doped TiO2, as anode for Lithium-ion rechargeable batteries, which led to improving charge-discharge capacity at 0.1 C and twice higher rate capability compared to that of nitrogen-doped TiO2 mesoporous microsphere at 10 C

Bi, Zhonghe [ORNL] [ORNL; Paranthaman, Mariappan Parans [ORNL] [ORNL; Guo, Bingkun [ORNL] [ORNL; Unocic, Raymond R [ORNL] [ORNL; Meyer III, Harry M [ORNL] [ORNL; Bridges, Craig A [ORNL] [ORNL; Sun, Xiao-Guang [ORNL] [ORNL; Dai, Sheng [ORNL] [ORNL

2014-01-01T23:59:59.000Z

215

Silica powders for powder evacuated thermal insulating panel and method  

DOE Patents [OSTI]

A powder evacuated thermal insulating panel using generally spherical and porous silica particles of a median size less than about 100 nanometers in diameter, a pour packing density of about 0.4 to 0.6 g/cm{sup 3} and an external surface area in the range of about 90 to 600 m{sup 2}/g is described. The silica powders are prepared by reacting a tetraalkyl silicate with ammonia and water in an alcohol solvent, distilling the solution after the reaction to remove the ammonia and recover the alcohol. The resulting aqueous slurry was dried, ball-milled, and dried again to provide the silica particles with defined internal and external porosity. The nanometer size and the large external surface area of the silica particles along with the internal and external porosity of the silica particles provide powder evacuated thermal insulating panels with significantly higher R-values than obtainable using previously known silica powders. 2 figs.

Harris, M.T.; Basaran, O.A.; Kollie, T.G.; Weaver, F.J.

1996-01-02T23:59:59.000Z

216

Silica powders for powder evacuated thermal insulating panel and method  

DOE Patents [OSTI]

A powder evacuated thermal insulating panel using generally spherical and porous silica particles of a median size less than about 100 nanometers in diameter, a pour packing density of about 0.4 to 0.6 g/cm.sup.3 and an external surface area in the range of about 90 to 600 m.sup.2/ g is described. The silica powders are prepared by reacting a tetraakyl silicate with ammonia and water in an alcohol solvent, distilling the solution after the reaction to remove the ammonia and recover the alcohol. The resulting aqueous slurry was dried, ball-milled, and dried again to provide the silica particles with defined internal and external porosity. The nanometer size and the large external surface area of the silica particles along with the internal and external porosity of the silica particles provide powder evacuated thermal insulating panels with significantly higher R-values than obtainable using previously known silica powders.

Harris, Michael T. (Knoxville, TN); Basaran, Osman A. (Oak Ridge, TN); Kollie, Thomas G. (Oak Ridge, TN); Weaver, Fred J. (Knoxville, TN)

1996-01-01T23:59:59.000Z

217

Silica powders for powder evacuated thermal insulating panel and method  

DOE Patents [OSTI]

A powder evacuated thermal insulating panel using generally spherical and porous silica particles of a median size less than about 100 nanometers in diameter, a pour packing density of about 0.4 to 0.6 g/cm.sup.3 and an external surface area in the range of about 90 to 600 m.sup.2 /g is described. The silica powders are prepared by reacting a tetraakyl silicate with ammonia and water in an alcohol solvent, distilling the solution after the reaction to remove the ammonia and recover the alcohol. The resulting aqueous slurry was dried, ball-milled, and dried again to provide the silica particles with defined internal and external porosity. The nanometer size and the large external surface area of the silica particles along with the internal and external porosity of the silica particles provide powder evacuated thermal insulating panels with significantly higher R-values than obtainable using previously known silica powders.

Harris, Michael T. (Knoxville, TN); Basaran, Osman A. (Oak Ridge, TN); Kollie, Thomas G. (Oak Ridge, TN); Weaver, Fred J. (Knoxville, TN)

1994-01-01T23:59:59.000Z

218

Silica powders for powder evacuated thermal insulating panel and method  

DOE Patents [OSTI]

A powder evacuated thermal insulating panel using generally spherical and porous silica particles of a median size less than about 100 nanometers in diameter, a pour packing density of about 0.4 to 0.6 g/cm.sup.3 and an external surface area in the range of about 90 to 600 m.sup.2/ g is described. The silica powders are prepared by reacting a tetraakyl silicate with ammonia and water in an alcohol solvent, distilling the solution after the reaction to remove the ammonia and recover the alcohol. The resulting aqueous slurry was dried, ball-milled, and dried again to provide the silica particles with defined internal and external porosity. The nanometer size and the large external surface area of the silica particles along with the internal and external porosity of the silica particles provide powder evacuated thermal insulating panels with significantly higher R-values than obtainable using previously known silica powders.

Harris, Michael T. (Knoxville, TN); Basaran, Osman A. (Oak Ridge, TN); Kollie, Thomas G. (Oak Ridge, TN); Weaver, Fred J. (Knoxville, TN)

1995-01-01T23:59:59.000Z

219

Microwave synthesis and electrochemical characterization of mesoporous carbon@Bi{sub 2}O{sub 3} composites  

SciTech Connect (OSTI)

Graphical abstract: An efficient and quick microwave method has been employed to prepare worm-like mesoporous carbon@Bi{sub 2}O{sub 3} composites for the first time. The electrochemical measurement shows the worm-like mesoporous carbon@Bi{sub 2}O{sub 3} composites exhibits excellent capacitance performance and the maximum specific capacitance is up to 386 F g{sup -1}. Research highlights: {yields} An efficient and quick microwave method has been employed. {yields} A worm-like mesoporous carbon@Bi{sub 2}O{sub 3} composites have been successfully prepared. {yields} This composite exhibits excellent capacitance performance. {yields} This composite could be a potential electrode material for the supercapacitors. -- Abstract: An efficient and quick microwave method has been employed to prepare worm-like mesoporous carbon@Bi{sub 2}O{sub 3} composites for the first time. As-prepared products have been characterized by X-ray diffraction, N{sub 2} adsorption-desorption, scanning electron microscopy, transmission electron microscopy and inductive coupled plasma atomic emission spectroscopy. The electrochemical measurement shows the worm-like mesoporous carbon@Bi{sub 2}O{sub 3} composites exhibits excellent capacitance performance and the maximum specific capacitance reaches 386 F g{sup -1}, three times more than the pure worm-like mesoporous carbon.

Xia, Nannan [Department of Chemistry and Institute of Nanochemistry, Jinan University, Guangzhou 510632 (China)] [Department of Chemistry and Institute of Nanochemistry, Jinan University, Guangzhou 510632 (China); Yuan, Dingsheng, E-mail: tydsh@jnu.edu.cn [Department of Chemistry and Institute of Nanochemistry, Jinan University, Guangzhou 510632 (China)] [Department of Chemistry and Institute of Nanochemistry, Jinan University, Guangzhou 510632 (China); Zhou, Tianxiang; Chen, Jingxing; Mo, Shanshan; Liu, Yingliang [Department of Chemistry and Institute of Nanochemistry, Jinan University, Guangzhou 510632 (China)] [Department of Chemistry and Institute of Nanochemistry, Jinan University, Guangzhou 510632 (China)

2011-05-15T23:59:59.000Z

220

Characterisation of Dust Particles Trapped in Silica Aerogels.  

E-Print Network [OSTI]

?? This thesis involves the study of dust particles trapped in silica aerogel for fusion dust diagnostics purpose. The low velocity impact experiments are done… (more)

Liu, Bing

2011-01-01T23:59:59.000Z

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

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

222

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

SciTech Connect (OSTI)

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

223

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

224

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

225

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

226

Electroactive Silica Nanoparticles for Biological Labeling. | EMSL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed NewcatalystNeutronEnvironmentZIRKLEEFFECTSHighElectroactive Silica Nanoparticles for

227

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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

228

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

E-Print Network [OSTI]

?? The focus of this work was to study the effects of flexible silica backbones on elastic properties of silica aerogels. Two routes were examined.… (more)

Randall, Jason P.

2010-01-01T23:59:59.000Z

229

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

SciTech Connect (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

230

High-performance carbon nanotube-implanted mesoporous carbon spheres for supercapacitors with low series resistance  

SciTech Connect (OSTI)

Research highlights: {yields} CNTs-implanted porous carbon spheres are prepared by using gelatin as soft template. {yields} Homogeneously distributed CNTs form a well-develop network in carbon spheres. {yields} CNTs act as a reinforcing backbone assisting the formation of pore structure. {yields} CNTs improve electrical conductivity and specific capacitance of supercapacitor. -- Abstract: Carbon nanotube-implanted mesoporous carbon spheres were prepared by an easy polymerization-induced colloid aggregation method using gelatin as a soft template. Scanning electron microscopy, transmission electron microscopy and nitrogen adsorption-desorption measurements reveal that the materials are mesoporous carbon spheres, with a diameter of {approx}0.5-1.0 {mu}m, a specific surface area of 284 m{sup 2}/g and average pore size of 3.9 nm. Using the carbon nanotube-implanted mesoporous carbon spheres as electrode material for supercapacitors in an aqueous electrolyte solution, a low equivalent series resistance of 0.83 {Omega} cm{sup 2} and a maximum specific capacitance of 189 F/g with a measured power density of 8.7 kW/kg at energy density of 6.6 Wh/kg are obtained.

Yi, Bin [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China)] [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China); Chen, Xiaohua, E-mail: hudacxh62@yahoo.com.cn [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China)] [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China); Guo, Kaimin [College of Physics and Electronic Science, Changsha University of Science and Technology (China)] [College of Physics and Electronic Science, Changsha University of Science and Technology (China); Xu, Longshan [Department of Mechanical Engineering, Xiamen University of Technology, Xiamen 361024 (China)] [Department of Mechanical Engineering, Xiamen University of Technology, Xiamen 361024 (China); Chen, Chuansheng [College of Physics and Electronic Science, Changsha University of Science and Technology (China)] [College of Physics and Electronic Science, Changsha University of Science and Technology (China); Yan, Haimei; Chen, Jianghua [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China)] [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China)

2011-11-15T23:59:59.000Z

231

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

SciTech Connect (OSTI)

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

232

Community Geothermal Technology Program: Silica bronze project. Final report  

SciTech Connect (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

ALUMINOSILICATE-COATED SILICA SAND FOR REACTIVE TRANSPORT EXPERIMENTS  

E-Print Network [OSTI]

ALUMINOSILICATE-COATED SILICA SAND FOR REACTIVE TRANSPORT EXPERIMENTS By JORGE ANTONIO JEREZ transport experiments; Dr. Barbara Williams and Jason Shira from University of Idaho for providing access-COATED SILICA SAND FOR REACTIVE TRANSPORT EXPERIMENTS Abstract by Jorge Antonio Jerez Briones, Ph.D. Washington

Flury, Markus

234

Development of Silica Aerogel with Any Density  

E-Print Network [OSTI]

Abstract–New production methods of silica aerogel with high and low refractive indices have been developed. A very slow shrinkage of alcogel at room temperature has made possible producing aerogel with high refractive indices of up to 1.265 without cracks. Even higher refractive indices than 1.08, the transmission length of the aerogel obtained from this technique has been measured to be about 10 to 20 mm at 400 nm wave length. A mold made of alcogel which endures shrinkage in the supercritical drying process has provided aerogel with the extremely low density of 0.009g/cm 3, which corresponds to the refractive index of 1.002. We have succeeded producing aerogel with a wide range of densities. I.

M. Tabata; I. Adachi; T. Fukushima; H. Kawai; H. Kishimoto; A. Kuratani; H. Nakayama; S. Nishida; T. Noguchi; K. Okudaira; Y. Tajima; H. Yano; H. Yokogawa; H. Yoshida

235

Ambient-pressure silica aerogel films  

SciTech Connect (OSTI)

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

236

Laser Damage Precursors in Fused Silica  

SciTech Connect (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

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

E-Print Network [OSTI]

filled   hollow   silica   nano-­?   and   microshells  nano-­? extracting  sensor.   Conclusions   The   adsorptive   properties   of   hollow  

Martinez, H. Paul

2011-01-01T23:59:59.000Z

238

Preparation, characterization and catalytic properties of MCM-48 supported tungstophosphoric acid mesoporous materials for green synthesis of benzoic acid  

SciTech Connect (OSTI)

MCM-48 and tungstophosphoric acid (HPW) were prepared and applied for the synthesis of HPW/MCM-48 mesoporous materials. The characterization results showed that HPW/MCM-48 obtained retained the typical mesopore structure of MCM-48, and the textural parameters decreased with the increase loading of HPW. The catalytic oxidation results of benzyl alcohol and benzaldehyde with 30% H{sub 2}O{sub 2} indicated that HPW/MCM-48 was an efficient catalyst for the green synthesis of benzoic acid. Furthermore, 35 wt% HPW/MCM-48 sample showed the highest activity under the reaction conditions. Highlights: • 5–45 wt% HPW/MCM-48 mesoporous catalysts were prepared and characterized. • Their catalytic activities for the green synthesis of benzoic acid were investigated. • HPW/MCM-48 was approved to be an efficient catalyst. • 5 wt% HPW/MCM-48 exhibited the highest catalytic activity.

Wu, Hai-Yan; Zhang, Xiao-Li; Chen, Xi; Chen, Ya; Zheng, Xiu-Cheng, E-mail: zhxch@zzu.edu.cn

2014-03-15T23:59:59.000Z

239

Brookhaven National Laboratory/National Synchrotron Light Source Subject: Operation of Nano-material Hood in Room 1-128  

E-Print Network [OSTI]

-material Hood in Room 1-128 Number: LS-ESH-0051 Revision: 1 Effective: 10/01/2007 Page 1 of 1 Keith Klaus John Procedure on Nanomaterial ES&H requires work that could generate dispersible nanoparticles be conducted of this file is the one on-line in the NSLS ESH website. Before using a printed copy, verify

Ohta, Shigemi

240

Post Doctoral Associate Position on Carbon Nanomaterials We are looking for a highly motivated, experienced, and talented Post Doctoral Scholar  

E-Print Network [OSTI]

-based Nanomaterials and Composites with Applications in Dye-Sensitized Solar Cells. This project is related to the Research Program "Advanced Materials for Highly Efficient Dye-Sensitized Solar Cells ­ AdMatDSC" funded of the project in the next generation of dye-sensitized solar cells devices. Description of the project

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.


241

DOI: 10.1002/adem.200700076 Novel Method for Synthesis of Nano-Materials: Combustion of Active  

E-Print Network [OSTI]

DOI: 10.1002/adem.200700076 Novel Method for Synthesis of Nano-Materials: Combustion of Active- and combustion synthesis. A combination of combustion and reactive solution approaches leads to so- called solution (aqueous) combustion synthesis (SCS) method.[1­3] Typically SCS involves a self-sustained reaction

Mukasyan, Alexander

242

Quantification of residual stress from photonic signatures of fused silica  

SciTech Connect (OSTI)

A commercially available grey-field polariscope (GFP) instrument for photoelastic examination is used to assess impact damage inflicted upon the outer-most pane of Space Shuttle windows made from fused silica. A method and apparatus for calibration of the stress-optic coefficient using four-point bending is discussed. The results are validated on known material (acrylic) and are found to agree with literature values to within 6%. The calibration procedure is then applied to fused-silica specimens and the stress-optic coefficient is determined to be 2.43 ± 0.54 × 10{sup ?12} Pa{sup ?1}. Fused silica specimens containing impacts artificially made at NASA’s Hypervelocity Impact Technology Facility (HIT-F), to simulate damage typical during space flight, are examined. The damage sites are cored from fused silica window carcasses and examined with the GFP. The calibrated GFP measurements of residual stress patterns surrounding the damage sites are presented.

Cramer, K. Elliott; Yost, William T. [NASA Langley Research Center, Hampton, VA 23681 (United States); Hayward, Maurice [College of William and Mary, Williamsburg, VA 23185 (United States)

2014-02-18T23:59:59.000Z

243

Preparation, characterization and applications of monolithic titania-silica aerogels.  

E-Print Network [OSTI]

??In this work, new monolithic titania-silica aerogel materials were developed and evaluated. It started with the synthesis using modified sol-gel processes to obtain crack-free monolithic… (more)

Cao, Shengli

2007-01-01T23:59:59.000Z

244

aminopropyl silica gel: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Summary: We present optical and X-ray radiographical characterization of silica aerogels with refractive index from 1.05 to 1.07 for a Cherenkov radiator. A novel pin-drying...

245

amorphous silica systems: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

progress in the development and mass production of large-area hydrophobic silica aerogels for use as radiators in the aerogel-based ring-imaging Cherenkov (A-RICH) counter,...

246

Operating Experience Level 3, Dangers of Respirable Silica  

Broader source: Energy.gov [DOE]

This Operating Experience Level 3 (OE-3) document provides information on a safety concern related to recurring worker exposure to dust containing crystalline silica at Department of Energy (DOE) sites.

247

Electrospinning of silica nanofibers: characterization and application to biosensing  

E-Print Network [OSTI]

; and the pore size is around several nanometers to a micrometer wide. In this work, the relationship between the diameter of electrospun silica fibers, experimental parameters such as concentration and voltage, and between pore size of the fiber membrane...

Tsou, Pei-Hsiang

2009-06-02T23:59:59.000Z

248

Experimental evaluation of heat transfer characteristics of silica nanofluid  

E-Print Network [OSTI]

The laminar convective heat transfer characteristics were investigated for silica nanofluid. An experimental loop was built to obtain heat transfer coefficients for single-phase nanofluids in a circular conduit in laminar ...

Zhang, Zihao, S.B. Massachusetts Institute of Technology

2010-01-01T23:59:59.000Z

249

Silica Extraction at the Mammoth Lakes Geothermal Site  

SciTech Connect (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

250

Linear and nonlinear optics of hybrid plasmon-exciton nanomaterials in the presence of overlapping resonances  

E-Print Network [OSTI]

We consider a hybrid plasmon-exciton system comprised of a resonant molecular subsystem and three Au wires supporting a dipole mode which can be coupled to a dark mode in controllable fashion by variation of a symmetry parameter. The physics of such a system under strong coupling conditions is examined in detail. It is shown that if two wires supporting the dark mode are covered with molecular layers the system exhibits four resonant modes for a strong coupling regime due to asymmetry and lifted degeneracy of the molecular state in this case, while upon having molecular aggregates covering the top wire with dipolar mode, three resonant modes appear. Pump-probe simulations are performed to scrutinize the quantum dynamics and find possible ways to control plasmon-exciton materials. It is demonstrated that one can design hybrid nanomaterials with highly pronounced Fano-type resonances when excited by femtosecond lasers.

Sukharev, Maxim; Pachter, Ruth

2015-01-01T23:59:59.000Z

251

Model simulation and experiments of flow and mass transport through a nano-material gas filter  

SciTech Connect (OSTI)

A computational model for evaluating the performance of nano-material packed-bed filters was developed. The porous effects of the momentum and mass transport within the filter bed were simulated. For the momentum transport, an extended Ergun-type model was employed and the energy loss (pressure drop) along the packed-bed was simulated and compared with measurement. For the mass transport, a bulk dsorption model was developed to study the adsorption process (breakthrough behavior). Various types of porous materials and gas flows were tested in the filter system where the mathematical models used in the porous substrate were implemented and validated by comparing with experimental data and analytical solutions under similar conditions. Good agreements were obtained between experiments and model predictions.

Yang, Xiaofan; Zheng, Zhongquan C.; Winecki, Slawomir; Eckels, Steve

2013-11-01T23:59:59.000Z

252

Thermal Conductivity of Ordered Mesoporous Titania Films Made from Nanocrystalline Building Blocks and Sol-Gel Reagents  

E-Print Network [OSTI]

significant attention due to their wide range of applications. They have been used in dye-sensitized solar cells for their wide band gap semiconductor properties.1 They have also been considered for solid oxide fuel cells as high proton conductivity porous exchange membranes.2 Mesoporous TiO2 is also a very

Pilon, Laurent

253

Intrinsic kinetics of lower alcohols: C2, C3 dehydration over Lewis acidic ordered mesoporous silicate: Zr-KIT-6  

E-Print Network [OSTI]

KIT-6 materials are large pore cubic Ia3d mesoporous silicate, with tunable pore size (4-12 nm) and pore wall thickness (4-6 nm). The three-dimensional structure of KIT-6 provides more mass transfer channels within the ...

Pan, Qing

2013-12-31T23:59:59.000Z

254

Facile synthesis of mesoporous core-shell TiO{sub 2} nanostructures from TiCl{sub 3}  

SciTech Connect (OSTI)

Highlights: {yields} Stable TiCl{sub 3} solution is adopted as Ti sources. {yields} Low-cost glucose assisted facile solvothermal reactions. {yields} Exquisite core-shell morphology and mesoporous structure of TiO{sub 2} nanostructures. {yields} Superior photocatalytic activity of TiO{sub 2} nanostructures in UV light irradiation. -- Abstract: The present study reports the synthesis and formation process of mesoporous core-shell TiO{sub 2} nanostructures by employing a glucose-assisted solvothermal process using water-ethanol mixture as solvent and subsequent calcination process at 550 {sup o}C for 4 h. X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy and nitrogen adsorption-desorption analysis were used to investigate the structural properties of these nanostructures. By optimizing the preparation conditions, especially the contents of water and ethanol in the mixture solvent, mesoporous core-shell TiO{sub 2} nanostructures were obtained. These mesoporous nanostructures have anatase phase and exhibit the superior photocatalytic activity. This synthesis route is facile due to the usage of stable and low-cost Ti precursor such as TiCl{sub 3} and is thus applicable for large-scale production.

Xue, Bin, E-mail: bxue@shou.edu.cn [Department of Chemistry, College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306 (China)] [Department of Chemistry, College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306 (China); Sun, Tao; Mao, Fang; Sun, Li-Chun; Yang, Wei [Department of Chemistry, College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306 (China)] [Department of Chemistry, College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306 (China); Xu, Zhu-De [Department of Chemistry, Zhejiang University, Hangzhou 310027 (China)] [Department of Chemistry, Zhejiang University, Hangzhou 310027 (China); Zhang, Xin [Chemical Engineering College, Inner Mongolia University of Technology, Hohhot 010051 (China)] [Chemical Engineering College, Inner Mongolia University of Technology, Hohhot 010051 (China)

2011-09-15T23:59:59.000Z

255

Synthesis of pore-variable mesoporous CdS and evaluation of its photocatalytic activity in degrading methylene blue  

SciTech Connect (OSTI)

Graphical abstract: - Highlights: • Self-templated synthesis of tubular CdS. • Cadmium complexes of aliphatic acids sustain the network of mesoporous structures. • Aliphatic acids affect the phase composition and particle size. • Pore size and volume vary with aliphatic acids having different hydrocarbonyl. - Abstract: In this study, mesoporous CdS polycrystallites have been synthesized using aliphatic acids of hexanoic acid, octanoic acid, and oleic acid as coordinating and capping agents, respectively. The fibrous Cd–fatty acid salts act as a template to form the tubular CdS. The organic species are found to be necessary for maintaining the network of mesoporous CdS. The characterization results indicate that the shorter carbon chain length in aliphatic acids favors the wurtzite phase and particle size growth the specific surface area, pore diameter and pore volume show a monotonic raise with increasing carbon chain. The photocatalytic activities of mesoporous CdS tubes exhibit much higher efficiency than those of nanosized CdS powders in decolorizing methylene blue under simulated visible light.

Zhang, Wei-Min, E-mail: chm_zhangwm@ujn.edu.cn [School of Chemistry and Chemical Engineering, University of Jinan (China); Jiang, Yao-Quan [School of Chemistry and Chemical Engineering, University of Jinan (China); Cao, Xiao-Yan [Key Laboratory of Marine Chemistry Theory and Technology, Ocean University of China, Ministry of Education (China); Chen, Meng; Ge, Dong-Lai [School of Chemistry and Chemical Engineering, University of Jinan (China); Sun, Zhong-Xi, E-mail: sunzx@ujn.edu.cn [School of Chemistry and Chemical Engineering, University of Jinan (China)

2013-10-15T23:59:59.000Z

256

Tuning the Optical Properties of Mesoporous TiO2 Films by Nanoscale Engineering  

SciTech Connect (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

257

Silica recovery and control in Hawaiian geothermal fluids  

SciTech Connect (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

258

Silica recovery and control in Hawaiian geothermal fluids. Final report  

SciTech Connect (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

259

A NEW CLASS MESOPOROUS ALUMINOPHOSPHATES AS POTENTIAL CATALYSTS IN THE UPGRADING PETROLEUM FEEDSTOCKS  

SciTech Connect (OSTI)

A comprehensive investigation was conducted towards the synthesis and catalytic evaluation of high surface areas, uniform pore size, mesoporous aluminophosphates (AlPO{sub 4}) as potential catalysts for the upgrading of heavy petroleum feedstock, such as heavy crudes and petroleum residuum. The influence of several synthesis variables (including, the nature of the reactants, chemical composition of reaction mixtures, time and temperature) on the synthesis and physicochemical characteristics of the resulting products was explored. Phosphoric acid and three different aluminum sources, namely, aluminum hydroxide, aluminum isopropoxide and psuedobohemite alumina, were used as the inorganic precursors. Cetyltrimethylammonium chloride (C{sub 16}TACl) surfactant was used as charge compensating cation and structure directing agent in the surfactant-micellar-mediated synthesis pathway employed. Synthesis were conducted from reaction mixtures within the following typical molar composition range: xAl{sub 2}O{sub 3}:P{sub 2}O{sub 5}:yC{sub 16}TMACl: zTHMAOH: wH{sub 2}O, where x = 0.29-2.34, y = 0.24-0.98, z = 0.34-1.95, w = 86-700. Selected materials were evaluated for the conversion of isopropylbenzene (cumene) in order to understand the nature of any acid sites created. The synthesis products obtained depended strongly on the molar composition of the synthesis mixture. A lamellar (layered) phase was favored by synthesis mixtures comprised of low Al/P ratios (<0.33), low TMAOH content, high C{sub 16}TACl concentrations and high synthesis temperature (110 C). Formation of the desired hexagonal (tubular) phase was favored by higher Al/P ratios and TMAOH content, pH range between 8-10, low C{sub 16}TACl concentration and ambient temperature. The aluminum source had significant influence on the products obtained. With aluminum hydroxide (A1(OH){sub 3}) as the hydroxide source, the resulting hexagonal phase in the ''as-synthesized'' form demonstrated well defined ordered mesoporous structure for synthesis mixtures of Al/P ratios in the range of 0.47-1.25, above which increasingly disordered products were observed. The products were however unstable to calcination in air above 400 C to remove the organic template, under which structural collapsed was observed. Products formed using pseudoboehmite alumina (catapal B), were more thermally stable than those formed with aluminum isopropoxide, though all products experienced some degree of structural collapsed on calcination and yielded micro- or micro-mesoporous materials ranging from low (<500 m{sup 2}/g) to high surface areas (>500 m{sup 2}/g) and pore sizes ranging from microporous (< 1.5 nm) in some products to mesoporous (up to 3.6 nm) in other. Improvement in thermal stability was not observed when Mg and Co or bridging organic functional groups were incorporated with the mesoporous framework. The products showed negligible activity for the conversion of cumene at 300 C. Further research is necessary to investigate alternative synthesis strategies to strengthen and improve the thermal stabilities of these aluminophosphates.

Conrad Ingram; Mark Mitchell

2005-08-31T23:59:59.000Z

260

Temperature and moisture dependence of dielectric constant for silica aerogels  

SciTech Connect (OSTI)

The dielectric constants of silica aerogels are among the lowest measured for any solid material. The silica aerogels also exhibit low thermal expansion and are thermally stable to temperatures exceeding 500{degrees}C. However, due to the open porosity and large surface areas for aerogels, their dielectric constants are strongly affected by moisture and temperature. This paper presents data for the dielectric constants of silica aerogels as a function of moisture content at 25{degrees}C, and as a function of temperature, for temperatures in the range from 25{degrees}C to 450{degrees}C. Dielectric constant data are also given for silica aerogels that are heat treated in dry nitrogen at 500{degrees}C, then cooled to 25{degrees}C for measurements in dry air. All measurements are made on bulk aerogel spheres at 22GHz microwave frequency, using a cavity perturbation method. The results of the dependence found here for bulk materials can be inferred to apply also to thin films of silica aerogels having similar nano-structures and densities.

Hrubesh, L.H., LLNL

1997-03-01T23:59:59.000Z

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

Surface characterization of silica glass substrates treated by atomic hydrogen  

SciTech Connect (OSTI)

Silica glass substrates with very flat surfaces were exposed to atomic hydrogen at different temperatures and durations. An atomic force microscope was used to measure root-mean-square (RMS) roughness and two-dimensional power spectral density (PSD). In the treatment with atomic hydrogen up to 900 °C, there was no significant change in the surface. By the treatment at 1000 °C, the changes in the RMS roughness and the PSD curves were observed. It was suggested that these changes were caused by etching due to reactions of atomic hydrogen with surface silica. By analysis based on the k-correlation model, it was found that the spatial frequency of the asperities became higher with an increase of the treatment time. Furthermore, the data showed that atomic hydrogen can flatten silica glass surfaces by controlling heat-treatment conditions. - Highlights: • Silica glass surface was treated by atomic hydrogen at various temperatures. • Surface roughness was measured by an atomic force microscope. • Roughness data were analyzed by two-dimensional power spectral density. • Atomic hydrogen can flatten silica glass surfaces.

Inoue, Hiroyuki [Institute of Industrial Science, The University of Tokyo, Meguro-ku, Tokyo 153-8505 (Japan); Masuno, Atsunobu, E-mail: masuno@iis.u-tokyo.ac.jp [Institute of Industrial Science, The University of Tokyo, Meguro-ku, Tokyo 153-8505 (Japan); Ishibashi, Keiji [Canon ANELVA Corporation, Asao-ku, Kawasaki, Kanagawa 215-8550 (Japan); Tawarayama, Hiromasa [Kawazoe Frontier Technologies Corporation, Kuden 931-113, Sakae-ku, Yokohama, Kanagawa 247-0014 (Japan); Zhang, Yingjiu; Utsuno, Futoshi [Institute of Industrial Science, The University of Tokyo, Meguro-ku, Tokyo 153-8505 (Japan); Koya, Kazuo; Fujinoki, Akira [Shin Etsu Quartz Prod. Co., Ltd., Res and Applicat Lab, Fukushima 963-0725 (Japan); Kawazoe, Hiroshi [Kawazoe Frontier Technologies Corporation, Kuden 931-113, Sakae-ku, Yokohama, Kanagawa 247-0014 (Japan)

2013-12-15T23:59:59.000Z

262

Mesoporous TiO2 beads for high efficiency CdS/ CdSe quantum dot co-sensitized solar cells  

E-Print Network [OSTI]

) as a derivative of dye-sensitized solar cells (DSCs) have attracted considerable attention and been regardedMesoporous TiO2 beads for high efficiency CdS/ CdSe quantum dot co-sensitized solar cells Ru Zhou for a CdS/CdSe quantum dot (QD) co-sensitized solar cell, which was constructed with the mesoporous TiO2

Cao, Guozhong

263

Vanadyl tert-Butoxy Orthosilicate, OV[OSi(OtBu)3]3: A Model for Isolated Vanadyl Sites on Silica and a  

E-Print Network [OSTI]

-containing silica aerogels and xerogels.13-17 In addition, vanadia-silica catalysts have been prepared by treating

Iglesia, Enrique

264

Silica membranes for hydrogen separation from coal gas. Final report  

SciTech Connect (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

265

E-Print Network 3.0 - aqueous silica sols Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

by supercritical CO2 extraction of silica sol-gels.14 But the very high porosity in aerogels contributes... Silica Monoliths Templated on L3 Liquid Crystal Abds-Sami Malik,,...

266

Experimental Simulation of Evaporation-Driven Silica Sinter Formation and Microbial Silicification in Hot Spring Systems  

E-Print Network [OSTI]

in geothermal waters after they have reached the surface. Water evaporation is, along with cooling, one Evaporation of silica-rich geothermal waters is one of the main abiotic drivers of the formation of silica

Paris-Sud XI, Université de

267

Evaluation and recommendations for reduction of a silica dust exposure  

E-Print Network [OSTI]

to the increase in active tuberculosis among silicotics previously discussed. Perhaps there is a synergistic effect between silicosis and various lung cancers. A 1999 paper by Checkoway("6) showed a significantly (p=0. 02) increasing trend of lung cancer..., and that 100, 000 are exposed to silica dust through sandblasting, rock drilling and mining operations. &sI Silica is the second- most-common mineral in the earth's crust and a major component of sand, rock and mineral ores so it is not surprising to find...

Gruben, Raymond L

2000-01-01T23:59:59.000Z

268

Project EARTH-11-RR4: Reconstructing the Cenozoic Silica Cycle using Sponge 30  

E-Print Network [OSTI]

to the oceans and the success of the diatoms. Although diversity curves suggest that diatoms radiated concident. The radiation of siliceous diatoms during the Cenozoic is thought to have forced the ocean from a high silica.e. enhanced silicate weathering due to the radiation of grasses on land drove increased silica supply

Henderson, Gideon

269

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

E-Print Network [OSTI]

Hierarchical Silica Nanostructures Inspired by Diatom Algae Yield Superior Deformability, Toughness algae that is mainly composed of amorphous silica, which features a hierarchical structure that ranges in diatom algae as a basis to study a bioinspired nanoporous material implemented in crystalline silica. We

Buehler, Markus J.

270

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

271

Multicomponent Transport of Sulfate in a Goethite-Silica Sand System  

E-Print Network [OSTI]

Multicomponent Transport of Sulfate in a Goethite-Silica Sand System at Variable pH and Ionic of protons and sulfate on goethite and silica were used in combination with a one-dimensional mass-transport model to predict the transport of sulfate at variable pH and ionic strength in a goethite-silica system

Sparks, Donald L.

272

Converting Homogeneous to Heterogeneous in Electrophilic Catalysis using Monodisperse Metal Nanoparticles  

E-Print Network [OSTI]

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

Witham, Cole A.

2011-01-01T23:59:59.000Z

273

E-Print Network 3.0 - alumina Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

photolithography... , etching, and structure releasing. EXPERIMENTAL PROCEDURE Aerogel preparation Mesoporous silica and alumina Source: Kim, Chang-Jin "CJ" - Department...

274

E-Print Network 3.0 - alumina vliyanie ionnogo Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

photolithography... , etching, and structure releasing. EXPERIMENTAL PROCEDURE Aerogel preparation Mesoporous silica and alumina Source: Kim, Chang-Jin "CJ" - Department...

275

Coagulation chemistries for silica removal from cooling tower water.  

SciTech Connect (OSTI)

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

276

Silica dust control when drilling concrete Page 1 of 2  

E-Print Network [OSTI]

Silica dust control when drilling concrete Page 1 of 2 Drilling into concrete releases a fine sandy and routinely drill into concrete are at risk of developing this disease. Controlling the dust Hammer drills are available with attached dust removal systems. These draw dust from the drill end, down the attachment

Knowles, David William

277

High temperature thermographic measurements of laser heated silica  

SciTech Connect (OSTI)

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

278

Fractal Studies on Titanium-Silica Aerogels using SMARTer  

SciTech Connect (OSTI)

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

279

Spatial Pattern Formation in Fused Silica Under UV Irradiation  

E-Print Network [OSTI]

Spatial Pattern Formation in Fused Silica Under UV Irradiation Problem Presenter Leslie Button lenses gradually degrades and ultimately damages these optical components. Corning is a global supplier of optical and ceramic materials across various industries and is particularly interested in this damage

Edwards, David A.

280

Development of Silica/Vanadia/ Titania Catalysts for Removal of  

E-Print Network [OSTI]

mercury (Hg0) from simulated coal-combustion flue gas. Experiments were carried out in fixed-bed reactorsDevelopment of Silica/Vanadia/ Titania Catalysts for Removal of Elemental Mercury from Coal-Combustion the composition and microstructures of SCR (selective catalytic reduction) catalysts for Hg0 oxidation in coal-combustion

Li, Ying

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

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

SciTech Connect (OSTI)

Experiments have been performed to obtain the transient response of a thin adiabatic packed bed of silica gel after a step change in inlet air conditions, comparisons are made with predictions using a solid-side resistance model and a pseudo-gas-side controlled model and better agreement obtained with the former model.

Pesaran, A. A.; Mills, A. F.

1986-08-01T23:59:59.000Z

282

Flue gas injection control of silica in cooling towers.  

SciTech Connect (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

283

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

E-Print Network [OSTI]

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

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

284

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

SciTech Connect (OSTI)

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

285

Single-crystal-like NiO colloidal nanocrystal-aggregated microspheres with mesoporous structure: Synthesis and enhanced electrochemistry, photocatalysis and water treatment properties  

SciTech Connect (OSTI)

A new microwave-assisted hydrothermal synthetic route based on the self-assembly and subsequently controlled thermal decomposition process is proposed to fabricate nickel oxide colloidal nanocrystal aggregated microspheres (CNAMs) with mesoporous structure. XRD, EDS, SEM, TEM. FTIR, and N{sub 2} adsorption and desorption isotherm techniques are employed for morphology and structure characterizations. The as-prepared nickel oxide CNAMs, which has a high surface area (234 m{sup 2}/g) with narrow pore distribution at around 3.25 nm, are composed of numerous hexagonal mesoporous nanocrystals of approximately 50–60 nm in size, and present a single-crystal-like characteristic. The experimental results also demonstrated that the CNAMs showed outstanding performance in electrochemistry, photocatalysis and waste water treatment due to their special hierarchical and mesoporous structure, presenting the promising candidate for catalysis and catalysis support materials. - Graphical abstract: CNAMs with mesoporous structure synthesized via a simple microwave-assisted hydrothermal method was applied in electrochemistry and catalysis and exhibited enhanced performance. Display Omitted - Highlights: • CNAMs with mesoporous structure are achieved via a simple microwave-assisted hydrothermal method. • Morphology, structure and pore distribution of sample particles is specifically controlled. • The samples show enhanced properties in electrochemistry and catalysis due to hierarchical structure.

Suo, Zhirong [Analytical and Testing Center, Southwest University of Science and Technology, Mianyang 621010 (China); Dong, Xiaonan [School of Materials Science and Engineering, Shaanxi University of Science and Technology, Xi’an 710021 (China); Liu, Hui, E-mail: liuhui@sust.edu.cn [School of Materials Science and Engineering, Shaanxi University of Science and Technology, Xi’an 710021 (China)

2013-10-15T23:59:59.000Z

286

Crystalline mesoporous tungsten oxide nanoplate monoliths synthesized by directed soft template method for highly sensitive NO{sub 2} gas sensor applications  

SciTech Connect (OSTI)

Graphical abstract: Display Omitted Highlights: ? Mesoporous WO{sub 3} nanoplate monoliths were obtained by direct templating synthesis. ? Enable effective accession of the analytic molecules for the sensor applications. ? The WO{sub 3} sensor exhibited a high performance to NO{sub 2} gas at low temperature. -- Abstract: Controllable synthesis of nanostructured metal oxide semiconductors with nanocrystalline size, porous structure, and large specific surface area is one of the key issues for effective gas sensor applications. In this study, crystalline mesoporous tungsten oxide nanoplate-like monoliths with high specific surface areas were obtained through instant direct-templating synthesis for highly sensitive nitrogen dioxide (NO{sub 2}) sensor applications. The copolymer soft template was converted into a solid carbon framework by heat treatment in an inert gas prior to calcinations in air to sustain the mesoporous structure of tungsten oxide. The multidirectional mesoporous structures of tungsten oxide with small crystalline size, large specific surface area, and superior physical characteristics enabled the rapid and effective accession of analytic gas molecules. As a result, the sensor response was enhanced and the response and recovery times were reduced, in which the mesoporous tungsten oxide based gas sensor exhibited a superior response of 21,155% to 5 ppm NO{sub 2}. In addition, the developed sensor exhibited selective detection of low NO{sub 2} concentration in ammonia and ethanol at a low temperature of approximately 150 °C.

Hoa, Nguyen Duc, E-mail: ndhoa@itims.edu.vn [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology (HUST) (Viet Nam); Duy, Nguyen Van [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology (HUST) (Viet Nam)] [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology (HUST) (Viet Nam); Hieu, Nguyen Van, E-mail: hieu@itims.edu.vn [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology (HUST) (Viet Nam)

2013-02-15T23:59:59.000Z

287

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

SciTech Connect (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

288

RE/ZrO{sub 2} (RE = Sm, Eu) composite oxide nano-materials: Synthesis and applications in photocatalysis  

SciTech Connect (OSTI)

Graphical abstract: - Highlights: • RE/ZrO{sub 2} (RE = Sm, Eu) nano-materials have been successfully synthesized. • Defect and electron structures determine the absorption properties on visible light. • Nano-sized Zr{sub 0.8}Sm{sub 0.2}O{sub 2??} has good visible-light-responsive photocatalytic activities. • In the future, it can be used in wastewater treatment and environmental protection. - Abstract: Zirconia modified by Samarium/Europium, RE/ZrO{sub 2} (RE = Sm, Eu), composite oxide nano-materials have been successfully synthesized by improved sol–gel method. Characterization results show that X-ray diffraction (XRD) peaks of products gradually shift to the lower angle with the increase of rare earth which implies that the lattice distances of RE/ZrO{sub 2} nano-materials are gradually enlarged. Moreover, the molar ratios between zirconium and rare earth are consistent with the chemical formula and both of them are uniformly distributed in samples. Optical properties indicate that defect structures and electron configurations of RE/ZrO{sub 2} (RE = Sm, Eu) with single phase determine their absorption properties on visible light. Photocatalytic experiments indicate Zr{sub 0.8}Sm{sub 0.2}O{sub 2??} nano-crystals have excellent visible-light-responsive photocatalytic activities on Methylene blue and Rhodamine B which results from the special defect structure, suitable electronic configuration, and larger specific surface area. It follows that Zr{sub 0.8}Sm{sub 0.2}O{sub 2??} nano-crystals are new visible-light-responsive photocatalysts which can be applied in dye wastewater treatment and environmental protection in the future.

Du, Weimin, E-mail: duweimin75@gmail.com [College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang, Henan 455002 (China); Zhu, Zhaoqiang [College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang, Henan 455002 (China); College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou, Henan 450001 (China); Zhang, Xiaofen; Wang, Dacheng; Liu, Donghe [College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang, Henan 455002 (China); Qian, Xuefeng [School of Chemistry and Chemical Technology, Shanghai Jiao Tong University, Shanghai 200240 (China); Du, Jimin, E-mail: djm@aynu.edu.cn [College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang, Henan 455002 (China)

2013-10-15T23:59:59.000Z

289

Silica aerogels modified by functional and nonfunctional organic groups  

SciTech Connect (OSTI)

Organically substituted silica aerogels were prepared from RSi(OR`){sub 3}/Si(OR`){sub 4} mixtures, followed by supercritical drying. The typical microstructure and the resulting physical properties of silica aerogels are retained, if the portion of R-Si units is below 10-20%. However, new properties are supplemented, such as hydrophobicity (which makes the aerogels insensitive towards moisture), a higher compliance, and the possibility to incorporate functional organic groups. Controlled pyrolysis of the organically substituted aerogels allows to coat the inner surface of the aerogels with nanometer-sized carbon structures. This results in a very efficient infrared opacification and improved heat insulation properties at high temperatures. 5 refs., 2 figs.

Schubert, U.; Huesing, N.; Schwertfeger, F. [Universitaet Wien (Austria)

1996-12-31T23:59:59.000Z

290

1 LOST PRODUCTION AS CONSEQUENSE OF SILICA SCALING IN CERRO  

E-Print Network [OSTI]

Mineral scale depositation occurs in many of the Cerro Prieto wells, but the main problems occurs by silica (SiO2) scale both pipes and reservoir zones close to the downhole. In Cerro Prieto geothermal field three types of scales are found; calcium carbonate (calcite), amorphous silica (SiO2), and metallic sulfides (mainly iron, and lesser lead and cooper). The scale causes lost production and it is necessary to make around 12 workover each year to recover the steam lost. When scaling problems occurred inside casing production is more easier to recover the production that scaling occurred in the reservoir zones, because it caused a skin damage (permeability decrease) in the reservoir zones close to the bottomhole. This paper analyze and discus the scaling problems and discuss the task developed to avoid and minimized the decline wells production, as to recover the production using workover alternatives.

Prieto Geothermal; Wells Mexico; Juan De; Dios Ocampo; Díaz Sara; Lilia Moya; Jesús De; León Vivar

291

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

292

Molecular engineering of porous silica using aryl templates  

DOE Patents [OSTI]

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

293

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

294

Supercritical carbon dioxide behavior in porous silica aerogel  

SciTech Connect (OSTI)

Analysis of the tails of the small-angle neutron scattering (SANS) intensities relevant to samples formed by porous silica and carbon dioxide at pressures ranging from 0 to 20 MPa and at temperatures of 308 and 353 K confirms that the CO2 fluid must be treated as a two-phase system. The first of these phases is formed by the fluid closer to the silica wall than a suitable distance [delta] and the second by the fluid external to this shell. The sample scattering-length densities and shell thicknesses are determined by the Porod invariants and the oscillations observed in the Porod plots of the SANS intensities. The resulting matter densities of the shell regions (thickness 15-35 {angstrom}) are approximately equal, while those of the outer regions increase with pressure and become equal to the bulk CO2 at the higher pressures only in the low-temperature case.

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

2011-01-01T23:59:59.000Z

295

Process for manufacturing hollow fused-silica insulator cylinder  

DOE Patents [OSTI]

A method for building hollow insulator cylinders that can have each end closed off with a high voltage electrode to contain a vacuum. A series of fused-silica round flat plates are fabricated with a large central hole and equal inside and outside diameters. The thickness of each is related to the electron orbit diameter of electrons that escape the material surface, loop, and return back. Electrons in such electron orbits can support avalanche mechanisms that result in surface flashover. For example, the thickness of each of the fused-silica round flat plates is about 0.5 millimeter. In general, the thinner the better. Metal, such as gold, is deposited onto each top and bottom surface of the fused-silica round flat plates using chemical vapor deposition (CVD). Eutectic metals can also be used with one alloy constituent on the top and the other on the bottom. The CVD, or a separate diffusion step, can be used to defuse the deposited metal deep into each fused-silica round flat plate. The conductive layer may also be applied by ion implantation or gas diffusion into the surface. The resulting structure may then be fused together into an insulator stack. The coated plates are aligned and then stacked, head-to-toe. Such stack is heated and pressed together enough to cause the metal interfaces to fuse, e.g., by welding, brazing or eutectic bonding. Such fusing is preferably complete enough to maintain a vacuum within the inner core of the assembled structure. A hollow cylinder structure results that can be used as a core liner in a dielectric wall accelerator and as a vacuum envelope for a vacuum tube device where the voltage gradients exceed 150 kV/cm.

Sampayan, Stephen E. (Manteca, CA); Krogh, Michael L. (Lee's Summit, MO); Davis, Steven C. (Lee's Summit, MO); Decker, Derek E. (Discovery Bay, CA); Rosenblum, Ben Z. (Overland Park, KS); Sanders, David M. (Livermore, CA); Elizondo-Decanini, Juan M. (Albuquerque, NM)

2001-01-01T23:59:59.000Z

296

Direct Access to Mesoporous Crystalline TiO2/Carbon Composites with Large and Uniform Pores for Use as Anode Materials in Lithium Ion Batteries  

SciTech Connect (OSTI)

Mesoporous and highly crystalline TiO{sub 2} (anatase)/carbon composites with large (>5?nm) and uniform pores were synthesized using PI-b-PEO block copolymers as structure directing agents. Pore sizes could be tuned by utilizing block copolymers with different molecular weights. The resulting mesoporous TiO{sub 2}/carbon was successfully used as an anode material for Li ion batteries. Without addition of conducting aid (Super P), the electrode showed high capacity during the first insertion/desertion cycle due to carbon wiring inside the walls of mesoporous TiO{sub 2}/carbon. The electrode further showed stable cycle performance up to 50 cycles and the specific charge capacity at 30?C was 38?mA h (g of TiO{sub 2}){sup ?1}, which indicates CCM-TiO{sub 2}/carbon can be used as a material for high rate use.

Lee, Jinwoo; Jung, Yoon S.; Warren, Scott C.; Kamperman, Marleen; Oh, Seung M.; DiSalvo, Francis J.; Wiesner, Ulrich

2011-01-01T23:59:59.000Z

297

Silica aerogel: An intrinsically low dielectric constant material  

SciTech Connect (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

298

Measurement of Radiation Damage on Silica Aerogel Cerenkov Radiator  

E-Print Network [OSTI]

We measured the radiation damage on silica aerogel Cerenkov radiators originally developed for the B-factory experiment at KEK. Refractive index of the aerogel samples ranged from 1.012 to 1.028. The samples were irradiated up to 9.8 MRad of equivalent dose. Measurements of transmittance and refractive index were carried out and these samples were found to be radiation hard. Deteriorations in transparency and changes of refractive index were observed to be less than 1.3% and 0.001 at 90% confidence level, respectively. Prospects of using aerogels under high-radiation environment are discussed. 1 Introduction Silica aerogels(aerogels) are a colloidal form of glass, in which globules of silica are connected in three dimensional networks with siloxan bonds. They are solid, very light, transparent and their refractive index can be controlled in the production process. Many high energy and nuclear physics experiments have used aerogels instead of pressurized gas for their Cerenkov coun...

Belle Preprint; Sahu Wang; M. Z. Wang; R. Suda; R. Enomoto; K. C. Peng; C. H. Wang; I. Adachi; M. Amami

299

The intense slow positron beam facility at the PULSTAR reactor and applications in nano-materials study  

SciTech Connect (OSTI)

An intense slow positron beam has been established at the PULSTAR nuclear research reactor of North Carolina State University. The slow positrons are generated by pair production in a tungsten moderator from gammarays produced in the reactor core and by neutron capture reactions in cadmium. The moderated positrons are electrostatically extracted and magnetically guided out of the region near the core. Subsequently, the positrons are used in two spectrometers that are capable of performing positron annihilation lifetime spectroscopy (PALS) and positron Doppler broadening spectroscopy (DBS) to probe the defect and free volume properties of materials. One of the spectrometers (e{sup +}-PALS) utilizes an rf buncher to produce a pulsed beam and has a timing resolution of 277 ps. The second spectrometer (Ps-PALS) uses a secondary electron timing technique and is dedicated to positronium lifetime measurements with an approximately 1 ns timing resolution. PALS measurements have been conducted in the e{sup +}-PALS spectrometer on a series of nano-materials including organic photovoltaic thin films, membranes for filtration, and polymeric fibers. These studies have resulted in understanding some critical issues related to the development of the examined nano-materials.

Liu, Ming; Moxom, Jeremy; Hawari, Ayman I. [Nuclear Reactor Program, Department of Nuclear Engineering, North Carolina State University, P.O. Box 7909, Raleigh, NC 27695 (United States); Gidley, David W. [Department of Physics, University of Michigan, 450 Church Street, Ann Arbor MI 48109 (United States)

2013-04-19T23:59:59.000Z

300

Multimodality Imaging with Silica-Based Targeted Nanoparticle Platforms  

SciTech Connect (OSTI)

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

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

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

DOE Patents [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

302

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

E-Print Network [OSTI]

polyethylene oxide solution Sunilkumar Khandavalli and Jonathan P. Rothsteina) Mechanical and Industrial rheology of fumed silica nanoparticles dispersed in an aqueous polyethylene oxide (PEO) solution

Rothstein, Jonathan

303

Biotransformation of Two-Line Silica-Ferrihydrite by a Dissimilatory...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

by a Dissimilatory Fe(III)-Reducing Bacterium: Formation of Carbonate Green Biotransformation of Two-Line Silica-Ferrihydrite by a Dissimilatory Fe(III)-Reducing...

304

E-Print Network 3.0 - acid-modified silica nanoparticles Sample...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

as 3D Scaffolds for New Materials: from Mechanically Strong Polymer Crosslinked Aerogels Summary: of X-aerogels where skeletal inorganic nanoparticles (e.g., silica and >30...

305

E-Print Network 3.0 - amorphous silica exposed Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

> >> Page: << < 1 2 3 4 5 > >> 81 Terahertz Time-Domain Spectroscopy Study of Silica Aerogels and Adsorbed Molecular Jiangquan Zhang and D. Grischkowsky* Summary: fundamental...

306

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

E-Print Network [OSTI]

Cherenkov radiators based on Silica aerogel are used to measure the electron bunch length at the photo injector test facility at DESY Zeuthen (PITZ). The energy range of those electrons is 4-5 MeV. In this paper the time resolution defined by the usage of aerogel is calculated analytically and Monte Carlo simulations are performed. It is shown that Silica aerogel gives the possibility to reach a time resolution of about 0.1 ps for high photon intensities and a time resolution of about 0.02 ps can be obtained for thin Silica aerogel radiators. Key words: silica aerogel, bunch length, time resolution, PITZ 1

J. Bähr A; V. Djordjadze A; D. Lipka A; A. Onuchin B; F. Stephan A

307

E-Print Network 3.0 - acid functionalized silica Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Materials Science ; Engineering 18 The influence of void space on antireflection coatings of silica nanoparticle self-assembled films Summary: nanoparticles on a silver...

308

E-Print Network 3.0 - amine catalyzed silica Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

the elastic modulus with epoxy loading, for an epoxy- crosslinked, amine-modified silica aerogel. Those... authors argued that the epoxy bridges the neighboring amine- modified...

309

E-Print Network 3.0 - acid modified silica Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

the elastic modulus with epoxy loading, for an epoxy- crosslinked, amine-modified silica aerogel. Those... authors argued that the epoxy bridges the neighboring amine- modified...

310

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

E-Print Network [OSTI]

??This thesis reports the findings of a study carried out to determine the effectiveness of Accelerated Tests in evaluating the Alkali-Silica Reactivity of Recycled Concrete… (more)

Johnson, Robert C (Author)

2011-01-01T23:59:59.000Z

311

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

312

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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

313

Construction of a multi-functional cryogenic propellant tank with cross-linked silica aerogel.  

E-Print Network [OSTI]

??Aerogels are low-density nanostructured porous materials, whose practical applications have been limited by their poor mechanical properties. Crosslinking the nanoparticle building blocks of silica aerogels… (more)

Reinheimer, Preston Glenn

2010-01-01T23:59:59.000Z

314

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

E-Print Network [OSTI]

??"Crosslinking of aerogels is a promising approach to combine the advantages of inorganic and polymeric materials. In the present study, two types of polyimide-silica hybrid… (more)

Patil, Vishal U., 1981-

2008-01-01T23:59:59.000Z

315

Nanomaterials for Bioimaging and Drug Delivery Tang Z, S He, H Pei, D Du, C Fan, and Y Lin. 2013. "Graphene-Based Optical  

E-Print Network [OSTI]

. "Graphene-Based Optical Biosensors and Imaging." Chapter 5 in Biosensors Based on Nanomaterials. 2013. "Graphene based materials for biomedical applications." Materials Today 16 (10), 365-373 · Wang Y Nucleotides Exploiting DNA/RNA Aptamers and Graphene Oxide Nanosheets." Analytical Chemistry 85

Dutta, Indranath

316

Thermal annealing of laser damage precursors on fused silica surfaces  

SciTech Connect (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 <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

317

Association of length-slow silica with evaporites  

SciTech Connect (OSTI)

In 1971, Folk and Pittman described the common occurrence of length-slow quartz (or lutecite) with evaporitic minerals, and they suggested that lutecite might be a useful indicator for vanished evaporites. However, the subsequent discoveries of length-slow silica in carbonate turbidites and in abyssal Pacific cherts revealed that lutecite is not restricted to near-surface deposits. Moreover, Kastner found that length-slow quartz could be crystallized in slightly alkaline solutions enriched in Mg[sup 2+], Na[sup +], and SO[sub 4][sup [minus]2]. Following these studies, researchers have cited the presence of lutecite in rock samples as suggestive but not compelling evidence for an evaporitic origin, and the precise nature of this form of silica has remained somewhat enigmatic. Investigations of chert nodules from evaporitic and non-evaporitic regimes support an identification of length-slow quartz'' with the mineral moganite, a polymorph of silica that is fibrous and optically length slow. Results are based upon X-ray powder diffraction of the chert, followed by Rietveld refinement of the X-ray patterns to quantify the weight fraction of quartz and moganite in each specimen. Most non-evaporitic chert appears to contain between 5 and 15 wt. % moganite, but evaporitic cherts often contain more than 20 wt. %. Cherts that have transformed from precursor magadiite can be particularly rich in moganite; samples from Lake Magadi, Kenya and from Harney Lake, Oregon revealed about equal parts moganite and quartz. However, the observation of decreasing abundances of moganite in rocks of increasing age indicates that moganite is metastable relative to quartz.

Heaney, P.J. (Princeton Univ., Princeton, NJ (United States). Dept. of Geology); Sheppard, R.A. (Geological Survey, Denver, CO (United States). Denver Federal Center); Post, J.E. (Smithsonian Inst., Washington, DC (United States). Dept. of Mineral Sciences)

1992-01-01T23:59:59.000Z

318

Modular Hybrid Plasma Reactor for Low Cost Bulk Production of Nanomaterials  

SciTech Connect (OSTI)

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

319

Chemical treatment for silica-containing glass surfaces  

DOE Patents [OSTI]

Dehydroxylated, silica-containing, glass surfaces are known to be at least partially terminated by strained siloxane rings. According to the invention, a surface of this kind is exposed to a selected silane compound or mixture of silane compounds under reaction-promoting conditions. The ensuing reaction results in opening of the strained siloxane rings, and termination of surface atoms by chemical species, such as organic or organosilicon species, having desirable properties. These species can be chosen to provide qualities such as hydrophobicity, or improved coupling to a polymeric coating. 11 figs.

Grabbe, A.; Michalske, T.A.; Smith, W.L.

1998-04-07T23:59:59.000Z

320

Chemical treatment for silica-containing glass surfaces  

DOE Patents [OSTI]

Dehydroxylated, silica-containing, glass surfaces are known to be at least partially terminated by strained siloxane rings. According to the invention, a surface of this kind is exposed to a selected silane compound or mixture of silane compounds under reaction-promoting conditions. The ensuing reaction results in opening of the strained siloxane rings, and termination of surface atoms by chemical species, such as organic or organosilicon species, having desirable properties. These species can be chosen to provide qualities such as hydrophobicity, or improved coupling to a polymeric coating.

Grabbe, Alexis (Albuquerque, NM); Michalske, Terry Arthur (Bernalillo, NM); Smith, William Larry (Albuquerque, NM)

1999-01-01T23:59:59.000Z

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.


321

Method for chemical surface modification of fumed silica particles  

DOE Patents [OSTI]

Dehydroxylated, silica-containing, glass surfaces are known to be at least partially terminated by strained siloxane rings. According to the invention, a surface of this kind is exposed to a selected silane compound or mixture of silane compounds under reaction-promoting conditions. The ensuing reaction results in opening of the strained siloxane rings, and termination of surface atoms by chemical species, such as organic or organosilicon species, having desirable properties. These species can be chosen to provide qualities such as hydrophobicity, or improved coupling to a polymeric coating. 11 figs.

Grabbe, A.; Michalske, T.A.; Smith, W.L.

1999-05-11T23:59:59.000Z

322

Chemical treatment for silica-containing glass surfaces  

DOE Patents [OSTI]

Dehydroxylated, silica-containing, glass surfaces are known to be at least partially terminated by strained siloxane rings. According to the invention, a surface of this kind is exposed to a selected silane compound or mixture of silane compounds under reaction-promoting conditons. The ensuing reaction results in opening of the strained siloxane rings, and termination of surface atoms by chemical species, such as organic or organosilicon species, having desirable properties. These species can be chosen to provide qualities such as hydrophobicity, or improved coupling to a polymeric coating.

Grabbe, Alexis (Albuquerque, NM); Michalske, Terry Arthur (Cedar Crest, NM); Smith, William Larry (Albuquerque, NM)

1999-01-01T23:59:59.000Z

323

Method for chemical surface modification of fumed silica particles  

DOE Patents [OSTI]

Dehydroxylated, silica-containing, glass surfaces are known to be at least partially terminated by strained siloxane rings. According to the invention, a surface of this kind is exposed to a selected silane compound or mixture of silane compounds under reaction-promoting conditions. The ensuing reaction results in opening of the strained siloxane rings, and termination of surface atoms by chemical species, such as organic or organosilicon species, having desirable properties. These species can be chosen to provide qualities such as hydrophobicity, or improved coupling to a polymeric coating.

Grabbe, Alexis (Albuquerque, NM); Michalske, Terry Arthur (Cedar Crest, NM); Smith, William Larry (Albuquerque, NM)

1999-01-01T23:59:59.000Z

324

Chemical treatment for silica-containing glass surfaces  

DOE Patents [OSTI]

Dehydroxylated, silica-containing, glass surfaces are known to be at least partially terminated by strained siloxane rings. According to the invention, a surface of this kind is exposed to a selected silane compound or mixture of silane compounds under reaction-promoting conditions. The ensuing reaction results in opening of the strained siloxane rings, and termination of surface atoms by chemical species, such as organic or organosilicon species, having desirable properties. These species can be chosen to provide qualities such as hydrophobicity, or improved coupling to a polymeric coating.

Grabbe, Alexis (Albuquerque, NM); Michalske, Terry Arthur (Cedar Crest, NM); Smith, William Larry (Albuquerque, NM)

1998-01-01T23:59:59.000Z

325

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

326

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.

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

2012-07-17T23:59:59.000Z

327

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

328

The production of activated silica with carbon dioxide gas  

E-Print Network [OSTI]

Ional to the per cent of carbon dioxi. de 1n the flue gas for a constant total gas flow rate. REFE REN CES l. Andrews, R. V, , Hanford Works Eocument (1952), 2. Andrews, R. V. & J. A. W. W. A, , ~46 82 (1954). 3. Andrews, R. V, , Personal Communication 4... of the reciuire . ents for the dedree of iliASTER OF SCIENCE Janus', 1956 Major Subject: Chemi. cal Engineering TH PRODUCTION OP ACTIVATED SILICA 7iIITH CARBON DIOXIDE GAS A Thesis William Bell Hayes III Approved as to style and content by: Chairmen...

Hayes, William Bell

1956-01-01T23:59:59.000Z

329

Silica Supported Ceria Nanoparticles: A Hybrid Nanostructure To Increase  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administrationcontroller systemsBi (2)Sharing Smart GridShift EndSidneyChemistry » Silica

330

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

331

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… (more)

Zuo, Yanjia

2010-01-01T23:59:59.000Z

332

Effect of carboxylic acid of periodic mesoporous organosilicas on the fructose-to-5-hydroxymethylfurfural conversion in dimethylsulfoxide systems  

SciTech Connect (OSTI)

This manuscript presents the preparation and catalytic application of highly ordered benzene bridged periodic mesoporous organosilicas (PMOs) functionalized with carboxylic acid (–COOH) group at varied density. The COOH-functionalized PMOs were synthesized by one-step condensation of 1,4-bis (triethoxysilyl) benzene and carboxylic group containing organosilane carboxyethylsilanetriol sodium salt using Brij-76 as the template. The obtained materials were characterized by a mean of methods including powder X-ray diffraction, nitrogen adsorption-desorption, scanning- and transmission electron microscopy, and {sup 13}C solid-state nuclear magnetic resonance measurements. The potentials of the obtained PMO materials with ordered mesopores were examined as solid catalysts for the chemical conversion of fructose to 5-hydroxymethylfurfural (HMF) in an organic solvent. The results showed that COOH-functionalized PMO with 10% COOH loading exhibited best results for the fructose to HMF conversion and selectivity. The high surface area, the adequate density acid functional group, and the strength of the PMO materials contributing to a promising catalytic ability were observed.

Dutta, Saikat; Wu, Kevin C.-W., E-mail: hmkao@cc.ncu.edu.tw, E-mail: kevinwu@ntu.edu.tw [Department of Chemical Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan (China); Kao, Hsien-Ming, E-mail: hmkao@cc.ncu.edu.tw, E-mail: kevinwu@ntu.edu.tw [Department of Chemistry, National Central University, Chung-Li 32054, Taiwan (China)

2014-11-01T23:59:59.000Z

333

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

E-Print Network [OSTI]

surface and EDA protonated products at air/liquid interfaces. The SFG spectra of EDA adsorbedEthylenediamine at Air/Liquid and Air/Silica Interfaces: Protonation Versus Hydrogen BondingKa (HOSit)) is between the two pKa values of EDA (in the range of 7.56-10.71) at the air/silica interface

334

Density hysteresis of heavy water confined in a nanoporous silica matrix  

E-Print Network [OSTI]

Density hysteresis of heavy water confined in a nanoporous silica matrix Yang Zhanga,b , Antonio of heavy water confined in a nanoporous silica matrix in a temperature-pressure range, from 300 to 130 K in the relevant phase region. More- over, the density data we obtained for the confined heavy water under

Chen, Sow-Hsin

335

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

E-Print Network [OSTI]

Friction and Heat Transfer Characteristics of Silica and CNT Nanofluids in a Tube Flow MILIVOJE M@niu.edu * www.kostic.niu.edu Abstract: - An apparatus for exploring friction and heat transfer characteristics flow. Initial turbulent friction and heat transfer measurements for silica and carbon nanotube (CNT

Kostic, Milivoje M.

336

The size and polydispersity of silica nanoparticles under simulated hot spring conditions  

E-Print Network [OSTI]

-through geothermal simu- lator system where polymerization was induced by rapid cooling. Changes in [SiO2], IS of silica nanoparticles in supersaturated geothermal waters was simulated using a flow-through geothermal of silica in active geothermal systems is a well-known process leading to the silicification

Benning, Liane G.

337

Mechanism of Elongation of Gold or Silver Nanoparticles in Silica by Irradiation with Swift Heavy Ions  

E-Print Network [OSTI]

1 Mechanism of Elongation of Gold or Silver Nanoparticles in Silica by Irradiation with Swift Heavy nanoparticles oriented parallel to one another can be synthesized in SiO2 by ion irradiation. Our aim, silica glass 1. Introduction Well-defined Au nanoparticles and nanorods are desirable for their optical

Boyer, Edmond

338

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

E-Print Network [OSTI]

A synthetic fused silica obtained from Tosoh SGM Co., ESL-1000 (OH % 1200 wt. ppm), with a thick- ness of 2 mmThe onset of optical breakdown in KrF-laser-irradiated silica glass surfaces Y. Kawaguchia,* , A Research Center, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 5, 1

Dickinson, J. Thomas

339

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

E-Print Network [OSTI]

1 Surface Analysis of Silica Gel Particles after Mechanical Dry Coating with Magnesium Stearate particles (d50 = 55 µm) by coating with different mass ratios of magnesium stearate - MgSt2 (d50 = 4.6 µm Group). Keywords: AFM phase imaging, adhesion force, dry coating, silica, magnesium stearate. 1

Paris-Sud XI, Université de

340

Pulsed infrared laser annealing of gold nanoparticles embedded in a silica A. Halabica,1,a  

E-Print Network [OSTI]

Pulsed infrared laser annealing of gold nanoparticles embedded in a silica matrix A. Halabica,1,a J; published online 28 April 2008 Pulsed infrared laser irradiation was used to modify the optical and physical in a fused-silica matrix. The experiments demonstrate the unique effects of fast thermal heating

Pennycook, Steve

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

ORIGINAL PAPER Algal-silica cycling and pigment diagenesis in recent alpine  

E-Print Network [OSTI]

dis- solved within 50 years of deposition. Diatom dissolu- tion, silica recycling, and diageneticO2, hereafter BSi) in lake sediments that has led to their common use in freshwater paleoecology have the lowest preservation potential for diatom frustules. However, the recycling of diatom silica

Konhauser, Kurt

342

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

E-Print Network [OSTI]

Subcritical crack growth in fused silica is treated as a stress assisted chemical reaction between water distilled water and pH 7 buffer solution, and the results are found to be similar. The fatigue parameters to the barrier height. The results show subcritical crack growth in high strength silica is dominated by entropy

Matthewson, M. John

343

Hybrid structure laser based on semiconductor nanowires and a silica microfiber knot cavity  

E-Print Network [OSTI]

Hybrid structure laser based on semiconductor nanowires and a silica microfiber knot cavity Qing://apl.aip.org/about/rights_and_permissions #12;Hybrid structure laser based on semiconductor nanowires and a silica microfiber knot cavity Qing 2009 We demonstrate a hybrid structure laser consisting of a single or multiple zinc oxide Zn

Wu, Shin-Tson

344

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

E-Print Network [OSTI]

Hybrid Silica-PVA Nanofibers via Sol-Gel Electrospinning Tahira Pirzada,,§ Sara A. Arvidson,,§ Carl: We report on the synthesis of poly(vinyl alcohol) (PVA)-silica hybrid nanofibers via sol-gel electro is under- taken and reveals a composition window in which defect-free hybrid nanofibers with diameters

Khan, Saad A.

345

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

E-Print Network [OSTI]

PLC Binbin Guan,1 Ryan P. Scott,1 Nicolas K. Fontaine,2 Tiehui Su,1 Carlo Ferrari,3 Mark Cappuzzo,3 on a silica planar lightwave circuit (PLC) coupled to a 3-D photonic circuit that efficiently generates planar lightwave circuit (PLC) with a silica 3-D PIC that supports up to 15 OAM modes, both TE and TM

Yoo, S. J. Ben

346

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

SciTech Connect (OSTI)

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

347

Characterization of zirconia- and niobia-silica mixture coatings produced by ion-beam sputtering  

SciTech Connect (OSTI)

ZrO{sub 2}-SiO{sub 2} and Nb{sub 2}O{sub 5}-SiO{sub 2} mixture coatings as well as those of pure zirconia (ZrO{sub 2}), niobia (Nb{sub 2}O{sub 5}), and silica (SiO{sub 2}) deposited by ion-beam sputtering were investigated. Refractive-index dispersions, bandgaps, and volumetric fractions of materials in mixed coatings were analyzed from spectrophotometric data. Optical scattering, surface roughness, nanostructure, and optical resistance were also studied. Zirconia-silica mixtures experience the transition from crystalline to amorphous phase by increasing the content of SiO{sub 2}. This also results in reduced surface roughness. All niobia and silica coatings and their mixtures were amorphous. The obtained laser-induced damage thresholds in the subpicosecond range also correlates with respect to the silica content in both zirconia- and niobia-silica mixtures.

Melninkaitis, Andrius; Tolenis, Tomas; Mazule, Lina; Mirauskas, Julius; Sirutkaitis, Valdas; Mangote, Benoit; Fu Xinghai; Zerrad, Myriam; Gallais, Laurent; Commandre, Mireille; Kicas, Simonas; Drazdys, Ramutis

2011-03-20T23:59:59.000Z

348

Dielectric and magnetic properties of some gadolinium silica nanoceramics  

SciTech Connect (OSTI)

Some nanostructure gadolinium silica glass-ceramics were obtained undergoing a sol gel method and a heat-treatment at 1000°C about two hours. The magnetic and dielectric properties of these samples were studied. The magnetic properties were evidenced performing susceptibility measurements in the 80-300K temperature range. A Curie-Weiss behavior has acquired. The values estimated for paramagnetic Curie temperature being small and positive suggest the presence of weak ferromagnetic interactions between Gd{sup 3+} ions. The dielectric properties were evaluated from dielectric permittivity (?{sub r}) and dielectric loss (tan?) measurements at the frequency 1 kHz, 10 kHz and 100 kHz, in the 25-225°C temperature range and dielectric dispersion at room temperature for 79.5 kHz - 1GHz frequency area. The dielectric properties suggest that the main polarization mechanism corresponds to interfacial polarization, characteristic for polycrystalline-structured dielectrics. The polycrystalline structure of the samples is due to the polymorphous transformations of the nanostructure silica crystallites in the presence of gadolinium oxide. They were highlighted by SEM micrographs.

Coroiu, I., E-mail: coroiu@phys.utcluj.ro; Pascuta, P., E-mail: coroiu@phys.utcluj.ro; Bosca, M., E-mail: coroiu@phys.utcluj.ro; Culea, E., E-mail: coroiu@phys.utcluj.ro [Technical University, Chemical and Physics Department, 28, Memorandumului, 400114, Cluj-Napoca (Romania)

2013-11-13T23:59:59.000Z

349

The LHCb RICH silica aerogel performance with LHC data  

E-Print Network [OSTI]

In the LHCb detector at the Large Hadron Collider, powerful charged particle identification is performed by Ring Imaging Cherenkov (RICH) technology. In order to cover the full geometric acceptance and the wide momentum range (1-100 GeV/c), two detectors with three Cherenkov radiators have been designed and installed. In the medium (10-40 GeV/c) and high (30-100 GeV/c) momentum range, gas radiators are used (C4F10 and CF4 respectively). In the low momentum range (1 to a few GeV/c) pion/kaon/proton separation will be done with photons produced in solid silica aerogel. A set of 16 tiles, with the large transverse dimensions ever (20x20 cm$^2$) and nominal refractive index 1.03 have been produced. The tiles have excellent optical properties and homogeneity of refractive index within the tile of ~1%. The first data collected at LHC are used to understand the behaviour of the RICH: preliminary results will be presented and discussed on the performance of silica aerogel and of the gas radiators C4F10 and CF4.

Perego, D L

2010-01-01T23:59:59.000Z

350

Synthesis and properties of Chitosan-silica hybrid aerogels  

SciTech Connect (OSTI)

Chitosan, a polymer that is soluble in dilute aqueous acid, is derived from chitin, a natural polyglucosamide. Aquagels where the solid phase consists of both chitosan and silica can be easily prepared by using an acidic solution of chitosan to catalyze the hydrolysis and condensation of tetraethylorthosilicate. Gels with chitosan/TEOS mass ratios of 0.1-1.1 have been prepared by this method. Standard drying processes using CO{sub 2} give the corresponding aerogels. The amount of chitosan in the gel plays a role in the shrinkage of the aerogel during drying. Gels with the lowest chitosan/silica ratios show the most linear shrinkage, up to 24%, while those with the highest ratios show only a 7% linear shrinkage. Pyrolysis at 700 C under nitrogen produces a darkened aerogel due to the thermal decomposition of the chitosan, however, the aerogel retains its monolithic form. The pyrolyzed aerogels absorb slightly more infrared radiation in the 2-5 {micro}m region than the original aerogels. B.E.T. surface areas of these aerogels range from 470-750 m{sup 2}/g. Biocompatibility screening of this material shows a very high value for hemolysis, but a low value for cytotoxicity.

Ayers, Michael R.; Hunt, Arlon J.

2001-06-01T23:59:59.000Z

351

Macroscopic Subdivision of Silica Aerogel Collectors for Sample Return Missions  

SciTech Connect (OSTI)

Silica aerogel collector tiles have been employed for the collection of particles in low Earth orbit and, more recently, for the capture of cometary particles by NASA's Stardust mission. Reliable, reproducible methods for cutting these and future collector tiles from sample return missions are necessary to maximize the science output from the extremely valuable embedded particles. We present a means of macroscopic subdivision of collector tiles by generating large-scale cuts over several centimeters in silica aerogel with almost no material loss. The cut surfaces are smooth and optically clear allowing visual location of particles for analysis and extraction. This capability is complementary to the smaller-scale cutting capabilities previously described [Westphal (2004), Ishii (2005a, 2005b)] for removing individual impacts and particulate debris in tiny aerogel extractions. Macroscopic cuts enable division and storage or distribution of portions of aerogel tiles for immediate analysis of samples by certain techniques in situ or further extraction of samples suited for other methods of analysis.

Ishii, H A; Bradley, J P

2005-09-14T23:59:59.000Z

352

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

353

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

E-Print Network [OSTI]

from pure sil- ica are widely used by the telecommunications industry and, because silica and silicates in models of silica Erik Lascaris,1 Mahin Hemmati,2 Sergey V. Buldyrev,3 H. Eugene Stanley,1 and C. Austen indicated the possible existence of a liquid-liquid critical point (LLCP) in models of silica at high

Stanley, H. Eugene

354

Research papers Polymerization of aqueous silica in H2OK2O solutions at 25200 C and 1 bar  

E-Print Network [OSTI]

Research papers Polymerization of aqueous silica in H2O­K2O solutions at 25­200 °C and 1 bar to 20 Aqueous silica polymerization Diamond anvil cell Alkaline uids Ab initio calculation Understanding the polymerization of aqueous silica is important for modeling uid­rock interactions at high pressure and temperature

Manning, Craig

355

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

E-Print Network [OSTI]

Aluminum and silica intake in drinking water and the risk of Alzheimer's disease or cognitive,2 , Commenges Daniel1,2 , Helmer Catherine2,3 , Jean-François Dartigues2,3 . Abbreviations: Al, Aluminum; AD, Alzheimer's Disease; MMSE, Mini Mental State Examination; Si, Silica Running head: Aluminum, silica in water

Paris-Sud XI, Université de

356

Apoptosis induction by silica nanoparticles mediated through reactive oxygen species in human liver cell line HepG2  

SciTech Connect (OSTI)

Silica nanoparticles are increasingly utilized in various applications including agriculture and medicine. In vivo studies have shown that liver is one of the primary target organ of silica nanoparticles. However, possible mechanisms of hepatotoxicity caused by silica nanoparticles still remain unclear. In this study, we explored the reactive oxygen species (ROS) mediated apoptosis induced by well-characterized 14 nm silica nanoparticles in human liver cell line HepG2. Silica nanoparticles (25–200 ?g/ml) induced a dose-dependent cytotoxicity in HepG2 cells. Silica nanoparticles were also found to induce oxidative stress in dose-dependent manner indicated by induction of ROS and lipid peroxidation and depletion of glutathione (GSH). Quantitative real-time PCR and immunoblotting results showed that both the mRNA and protein expressions of cell cycle checkpoint gene p53 and apoptotic genes (bax and caspase-3) were up-regulated while the anti-apoptotic gene bcl-2 was down-regulated in silica nanoparticles treated cells. Moreover, co-treatment of ROS scavenger vitamin C significantly attenuated the modulation of apoptotic markers along with the preservation of cell viability caused by silica nanoparticles. Our data demonstrated that silica nanoparticles induced apoptosis in human liver cells, which is ROS mediated and regulated through p53, bax/bcl-2 and caspase pathways. This study suggests that toxicity mechanisms of silica nanoparticles should be further investigated at in vivo level. -- Highlights: ? We explored the mechanisms of toxicity caused by silica NPs in human liver HepG2 cells. ? Silica NPs induced a dose-dependent cytotoxicity in HepG2 cells. ? Silica NPs induced ROS generation and oxidative stress in a dose-dependent manner. ? Silica NPs were also modulated apoptosis markers both at mRNA and protein levels. ? ROS mediated apoptosis induced by silica NPs was preserved by vitamin C.

Ahmad, Javed [Department of Zoology, College of Science, King Saud University, Riyadh 11451 (Saudi Arabia)] [Department of Zoology, College of Science, King Saud University, Riyadh 11451 (Saudi Arabia); Ahamed, Maqusood, E-mail: maqusood@gmail.com [King Abdullah Institute for Nanotechnology, King Saud University, Riyadh 11451 (Saudi Arabia)] [King Abdullah Institute for Nanotechnology, King Saud University, Riyadh 11451 (Saudi Arabia); Akhtar, Mohd Javed [Fibre Toxicology, CSIR-Indian Institute of Toxicology Research, Lucknow-226001 (India)] [Fibre Toxicology, CSIR-Indian Institute of Toxicology Research, Lucknow-226001 (India); Alrokayan, Salman A. [King Abdullah Institute for Nanotechnology, King Saud University, Riyadh 11451 (Saudi Arabia)] [King Abdullah Institute for Nanotechnology, King Saud University, Riyadh 11451 (Saudi Arabia); Siddiqui, Maqsood A.; Musarrat, Javed; Al-Khedhairy, Abdulaziz A. [Department of Zoology, College of Science, King Saud University, Riyadh 11451 (Saudi Arabia)] [Department of Zoology, College of Science, King Saud University, Riyadh 11451 (Saudi Arabia)

2012-03-01T23:59:59.000Z

357

INFLUENCE OF PHENYLTRIMETHOXYSILANE ON PHYSICOCHEMICAL PROPERTIES OF TEOS BASED MONOLITHIC SILICA AEROGELS PREPARED BY SUPERCRITICAL DRYING PROCESS  

E-Print Network [OSTI]

The objective of the present research work is to synthesize transparent, hydrophobic, monolithic silica aerogels with ultralow density by using supercritical drying process. The effect of phenyltrimethoxysilane as a hydrophobic reagent on the physicochemical properties of the silica aerogels has been studied. The total processing time for the synthesis of monolithic silica aerogels minimized to 29 h which was ~2 days. We have succeeded to get ultralow density of the silica aerogels as low as 24 Kgm-3 with 165 ° water droplet contact angle. The ultralow density affects the thermal conductivity of the silica aerogels.

Kavale Mahendra S; Mahadik D. B; Parale V. G; Mane P. B; Vhatkar R. S; A. Venkateswara Rao; Wagh P. B; Satish C. Gupta

358

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

SciTech Connect (OSTI)

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

359

Hydrogen and oxygen adsorption stoichiometries on silica supported ruthenium nanoparticles  

SciTech Connect (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

360

Mechanical Loss in Tantala/Silica Dielectric Mirror Coatings  

E-Print Network [OSTI]

Current interferometric gravitational wave detectors use test masses with mirror coatings formed from multiple layers of dielectric materials, most commonly alternating layers of SiO2 (silica) and Ta2O5 (tantala). However, mechanical loss in the Ta2O5/SiO2 coatings may limit the design sensitivity for advanced detectors. We have investigated sources of mechanical loss in the Ta2O5/SiO2 coatings, including loss associated with the coating-substrate interface, with the coating-layer interfaces, and with the bulk material. Our results indicate that the loss is associated with the bulk coating materials and that the loss of Ta2O5 is substantially larger than that of SiO2.

Steven D. Penn; Peter H. Sneddon; Helena Armandula; Joseph C. Betzwieser; Gianpietro Cagnoli; Jordan Camp; D. R. M. Crooks; Martin M. Fejer; Andri M. Gretarsson; Gregory M. Harry; Jim Hough; Scott E. Kittelberger; Michael J. Mortonson; Roger Route; Sheila Rowan; Christophoros C. Vassiliou

2003-02-24T23:59:59.000Z

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.


361

Studies of Immobilized Homogeneous Metal Catalysts on Silica Supports  

SciTech Connect (OSTI)

The tethered, chiral, chelating diphosphine rhodium complex, which catalyzes the enantioselective hydrogenation of methyl-{alpha}-acetamidocinnamate (MAC), has the illustrated structure as established by {sup 31}P NMR and IR studies. Spectral and catalytic investigations also suggest that the mechanism of action of the tethered complex is the same as that of the untethered complex in solution. The rhodium complexes, [Rh(COD)H]{sub 4}, [Rh(COD){sub 2}]{sup +}BF{sub 4}{sup -}, [Rh(COD)Cl]{sub 2}, and RhCl{sub 3} {center_dot} 3H{sub 2}O, adsorbed on SiO{sub 2} are optimally activated for toluene hydrogenation by pretreatment with H{sub 2} at 200 C. The same complexes on Pd-SiO{sub 2} are equally active without pretreatments. The active species in all cases is rhodium metal. The catalysts were characterized by XPS, TEM, DRIFTS, and mercury poisoning experiments. Rhodium on silica catalyzes the hydrogenation of fluorobenzene to produce predominantly fluorocyclohexane in heptane and 1,2-dichloroethane solvents. In heptane/methanol and heptane/water solvents, hydrodefluorination to benzene and subsequent hydrogenation to cyclohexane occurs exclusively. Benzene inhibits the hydrodefluorination of fluorobenzene. In DCE or heptane solvents, fluorocyclohexane reacts with hydrogen fluoride to form cyclohexene. Reaction conditions can be chosen to selectively yield fluorocyclohexane, cyclohexene, benzene, or cyclohexane. The oxorhenium(V) dithiolate catalyst [-S(CH{sub 2}){sub 3}s-]Re(O)(Me)(PPh{sub 3}) was modified by linking it to a tether that could be attached to a silica support. Spectroscopic investigation and catalytic oxidation reactivity showed the heterogenized catalyst's structure and reactivity to be similar to its homogeneous analog. However, the immobilized catalyst offered additional advantages of recyclability, extended stability, and increased resistance to deactivation.

Keith James Stanger

2003-05-31T23:59:59.000Z

362

Synthesis and characterization of barium ferrite–silica nanocomposites  

SciTech Connect (OSTI)

In this work, we prepared barium ferrite-silica (BaM-SiO{sub 2}) nanocomposites of different molar ratios by high-energy ball milling, followed by heat-treatment at different temperatures. The microstructure, morphology and magnetic properties were characterized for different synthesis conditions by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM). The results indicate that 15 h of milling was enough to avoid the generation of hematite phase and to get a good dispersion of barium ferrite particles in the ceramic matrix. For milling periods beyond 15 h and heat treatment above 900 °C, the XRD patterns showed the presence of hematite phase caused by the decomposition of BaM. The agglomerate size observed through SEM analysis was around 150 nm with a good BaM dispersion into the SiO{sub 2} matrix. The highest saturation magnetization (Ms) value obtained was 43 emu/g and the corresponding coercivity (Hc) value of 3.4 kOe for the composition 60BaM-40SiO{sub 2} milled for 15 h and heat treated at 900 °C. This coercivity value is acceptable for the application in magnetic recording media. Highlights: • Barium ferrite–silica nanocomposites were prepared by high energy ball milling. • Optimal processing time is 15 h milling and heat treatment at 900 °C. • This is enough to avoid the generation of hematite phase. • Obtain good dispersion of barium ferrite particles in the ceramic matrix • Above this processing time shows the presence of increased amount of hematite.

Aguilar-González, M.A.; Mendoza-Suárez, G.; Padmasree, K.P., E-mail: padma512@yahoo.com

2013-10-15T23:59:59.000Z

363

Strong Sulfur Binding with Conducting Magneli-Phase TinO2n-1 Nanomaterials for Improving Lithium-Sulfur Batteries  

E-Print Network [OSTI]

will go through a series of soluble intermediate higher-order polysulfides (Li2S8, Li2S6, and Li2S4 of Li2S2, Li2S, and sulfur.6-8 In order to solve these challenges, there have been recent developmentsStrong Sulfur Binding with Conducting Magneli-Phase TinO2n-1 Nanomaterials for Improving Lithium-Sulfur

Cui, Yi

364

Effect of oxidizer on grain size and low temperature DC electrical conductivity of tin oxide nanomaterial synthesized by gel combustion method  

SciTech Connect (OSTI)

Nanocrystalline Tin oxide material with different grain size was synthesized using gel combustion method by varying the fuel (C{sub 6}H{sub 8}O{sub 7}) to oxidizer (HNO{sub 3}) molar ratio by keeping the amount of fuel as constant. The prepared samples were characterized by using X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Energy Dispersive Analysis X-ray Spectroscopy (EDAX). The effect of fuel to oxidizer molar ratio in the gel combustion method was investigated by inspecting the grain size of nano SnO{sub 2} powder. The grain size was found to be reduced with the amount of oxidizer increases from 0 to 6 moles in the step of 2. The X-ray diffraction patterns of the calcined product showed the formation of high purity tetragonal tin (IV) oxide with the grain size in the range of 12 to 31 nm which was calculated by Scherer's formula. Molar ratio and temperature dependence of DC electrical conductivity of SnO{sub 2} nanomaterial was studied using Keithley source meter. DC electrical conductivity of SnO{sub 2} nanomaterial increases with the temperature from 80K to 300K. From the study it was observed that the DC electrical conductivity of SnO{sub 2} nanomaterial decreases with the grain size at constant temperature.

Rajeeva, M. P., E-mail: jayanna60@gmail.com; Jayanna, H. S., E-mail: jayanna60@gmail.com; Ashok, R. L.; Naveen, C. S. [Department of P.G. Studies and Research in Physics, Kuvempu University, Jnanasahyadri, Shankarghatta, Shimoga- 577451, Karnataka (India); Bothla, V. Prasad [Department of Physics, Indian Institute of Science, Bangalore-560012 (India)

2014-04-24T23:59:59.000Z

365

KrF- and ArF-excimer-laser-induced absorption in silica glasses produced by melting synthetic silica powder  

SciTech Connect (OSTI)

KrF- and ArF-excimer-laser-induced absorption of silica glasses produced by electric melting and flame fusion of synthetic silica powder were investigated. The growth of KrF-laser-induced absorption was more gradual than that of ArF-laser-induced absorption. Induced absorption spectra exhibited a peak at about 5.8 eV, of which the position and width differed slightly among samples and laser species. Widths of ArF-laser-induced absorption spectra were wider than those of KrF-laser-induced spectra. KrF-laser-induced absorption is reproducible by two Gaussian absorption bands peaking at 5.80 eV with full width at half maximum (FWHM) of 0.62 eV and at 6.50 eV with FWHM of 0.74 eV. For reproduction of ArF-laser-induced absorption, Gaussian bands at 5.41 eV with FWHM of 0.62 eV was necessary in addition to components used for reproducing KrF-laser-induced absorption. Based on the discussion of the change of defect structures evaluated from change of absorption components, we proposed that the precursor of the 5.8-eV band ascribed to E Prime center ({identical_to}Si{center_dot}) is {identical_to}Si-H HO-Si{identical_to} structures formed by the reaction between strained Si-O-Si bonds and interstitial H{sub 2} molecules during the irradiation.

Kuzuu, Nobu; Sasaki, Toshiya; Kojima, Tatsuya [Department of Applied Physics, University of Fukui, 3-9-1 Bunkyo, Fukui-shi, Fukui 910-8507 (Japan); Tanaka, Jun-ichiro; Nakamura, Takayuki; Horikoshi, Hideharu [Tosoh SGM Corp., 4555 Kaisei-cho, Shunan-shi, Yamaguchi 746-0006 (Japan)

2013-07-07T23:59:59.000Z

366

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

SciTech Connect (OSTI)

This invention relates to hydrothermally treated silica-alumina cogels resulting in a reduction in the NH/sub 4/ content of the gel and the employment of such gels as cracking catalysts.

Alafandi, H.; Stamires, D.

1980-12-09T23:59:59.000Z

367

E-Print Network 3.0 - aluminate-silica fume mixtures Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

< 1 2 3 4 5 > >> Page: << < 1 2 3 4 5 > >> 21 Carbon 39 (2001) 19952001 Silane-treated carbon fiber for reinforcing cement Summary: -treated carbon fibers and silane-treated silica...

368

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

using a Kaufman type ion source to figure 8 cm diameter fused silica and silicon carbide samples... cases are shown in Table 1 and Figure 1. Using a 3 cm diameter Ion Tech...

369

ORNL devises recipe to fine-tune diameter of silica rods | ornl...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

the stage for advances in anti-reflective solar cells, computer monitors, TV screens, eye glasses and more. The goal of fabricating fixed-size one-dimensional silica structures...

370

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

371

Fundamental Studies on Polymer and Organic-Inorganic Hybrid Nanoparticles Reinforced Silica Aerogels.  

E-Print Network [OSTI]

??The objective of this research was to reinforce silica aerogels using functional organic-inorganic hybrid nanoparticles, silane end-capped polyurethane oligomer and chain extended polymer, and self-crosslinkable… (more)

Duan, Yannan

2012-01-01T23:59:59.000Z

372

Study of the Behavior of a Commercial Scale Inhibitor on Silica Sand  

E-Print Network [OSTI]

squeeze lifetimes in order to minimize the number of treatments, thus reducing the cost. The objective of this thesis is to study the adsorption of the commercial scale inhibitor SI onto silica sand. By investigating this intrinsic phenomenon, an optimized...

Vaca Bustamante, Victor

2010-12-14T23:59:59.000Z

373

E-Print Network 3.0 - abundant circumstellar silica Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

67 doi:10.1016S0016-7037(03)00461-7 Pristine presolar silicon carbide Summary: silica coatings of as much as several tens of nm thickness, perhaps due to oxidation of the Si......

374

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

results for: alcali-silica reactions mechanisms Page: << < 1 2 3 4 5 > >> 1 GTQ, Chemistry 212, Dr. Glaser, FS96 --1 --GTQ on Baeyer-Villiger Reaction. (20 points,...

375

Laser-induced fluorescence of fused silica irradiated by ArF excimer laser  

SciTech Connect (OSTI)

Laser-induced fluorescence (LIF) of high-purity fused silica irradiated by ArF excimer laser is studied experimentally. LIF bands of the fused silica centered at 281 nm, 478 nm, and 650 nm are observed simultaneously. Furthermore, the angular distribution of the three fluorescence peaks is examined. Microscopic image of the laser modified fused silica indicates that scattering of the generated fluorescence by laser-induced damage sites is the main reason for the angular distribution of LIF signals. Finally, the dependence of LIF signals intensities of the fused silica on laser power densities is presented. LIF signals show a squared power density dependence, which indicates that laser-induced defects are formed mainly via two-photon absorption processes.

Zhang Haibo [Shanghai Key Laboratory of All Solid-state Laser and Applied Techniques, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Science, Shanghai 201800 (China); Graduate University of Chinese Academy of Science, Beijing 100049 (China); Yuan Zhijun; Zhou Jun; Dong Jingxing; Wei Yunrong; Lou Qihong [Shanghai Key Laboratory of All Solid-state Laser and Applied Techniques, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Science, Shanghai 201800 (China)

2011-07-01T23:59:59.000Z

376

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

377

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

; Engineering 100 By-Products Utilization Summary: of Recycled Aggregates in Self-Compacting4 Concrete", Fly Ash, Silica Fume, Slag and Natural Pozzolans... (0.00028 in.). For...

378

Treatment of domestic wastewater for reuse with activated silica and magnesia  

E-Print Network [OSTI]

which are of concern in treat- ment for potable purposes are organics and trace inorganics. This research project was conducted in an attempt to determine if organic oxides such as activated silica and magnesia in various combinations with alum... in Wastewater Toxic Inorganics in Wastewater Existing Technology Coagulation and Flocculation Lime Coagulation . . ~ Alum Coagulation . ~ ~ ~ ~ Activated Silica Magnesia 5 6 8 9 10 13 14 15 16 III EXPERIMENTAL PLAN Was tewater ~ ~ ~ ~ ~ Jar...

Lindner, John Howard

1985-01-01T23:59:59.000Z

379

Luminescent studies of fluorescent chromophore-doped silica aerogels for flat panel display applications  

SciTech Connect (OSTI)

The remarkable optical and electronic properties of doped and undoped silica aerogels establish their utility as unique, mulitfunctional host materials for fluorescent dyes and other luminescent materials for display and imaging applications. We present results on the photoluminescence, absorption, and photoluminescence excitation spectra of undoped silica aerogels and aerogels doped with Er{sup 3+}, rhodamine 6G (R6G), and fluorescein. 4 refs., 12 figs.

Glauser, S.A.C. [California Univ., Davis, CA (United States). Dept. of Applied Science; Lee, H.W.H. [Lawrence Livermore National Lab., CA (United States)

1997-04-01T23:59:59.000Z

380

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

E-Print Network [OSTI]

synthesis routes derived from sol-gel chemistry .......................... 4 1.3 Polymerization behavior of aqueous silica ............................................................ 11 1.4 Simulated structures from various growth models... are still used; however, the use of sol-gel chemistry for silica matrix construction permits the greatest degree of design flexibility and variety of materials that can be synthesized. Common synthesis techniques derived from sol-gel chemistry have been...

Lunn, Jonathan D.

2011-08-08T23:59:59.000Z

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.


381

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

SciTech Connect (OSTI)

We examine the effect of lattice temperature on the probability of surface damage initiation for 355nm, 7ns laser pulses for surface temperatures below the melting point to temperatures well above the melting point of fused silica. At sufficiently high surface temperatures, damage thresholds are dramatically reduced. Our results indicate a temperature activated absorption and support the idea of a lattice temperature threshold of surface damage. From these measurements, we estimate the temperature dependent absorption coefficient for intrinsic silica.

Bude, J; Guss, G; Matthews, M; Spaeth, M L

2007-10-31T23:59:59.000Z

382

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

E-Print Network [OSTI]

SILICA &ID ACID-DETERGENT FIBER CONTENT OF FIVE VARIETIES OF BERMUDAGRASS A Thesis by FREDERICK MICHAEL JUNGMAN Submitted to the Graduate College of Texas A&M Uniuersity in partial fulfillment of the requirements for the degree of MASTER... OF SCIENCE August 1971 Major Subject: Agronomy SILICA AND ACID-DETERGENT FIBER CONTENT 01' FIVE VARIETIES OF BEI~DAGRASS A Thesis by FREDERICK MICHAEL OUNGMAN Approved as to style and content by: (Chai rman of Coamd t tee) (llead of. Department...

Jungman, Frederick Michael

1971-01-01T23:59:59.000Z

383

Templated Control of Au nanospheres in Silica Nanowires  

SciTech Connect (OSTI)

The formation of regularly-spaced metal nanostructures in selectively-placed insulating nanowires is an important step toward realization of a wide range of nano-scale electronic and opto-electronic devices. Here we report templated synthesis of Au nanospheres embedded in silica nanowires, with nanospheres consistently spaced with a period equal to three times their diameter. Under appropriate conditions, nanowires form exclusively on Si nanostructures because of enhanced local oxidation and reduced melting temperatures relative to templates with larger dimensions. We explain the spacing of the nanospheres with a general model based on a vapor-liquid-solid mechanism, in which an Au/Si alloy dendrite remains liquid in the nanotube until a critical Si concentration is achieved locally by silicon oxide-generated nanowire growth. Additional Si oxidation then locally reduces the surface energy of the Au-rich alloy by creating a new surface with minimum area inside of the nanotube. The isolated liquid domain subsequently evolves to become an Au nanosphere, and the process is repeated.

Tringe, J W; Vanamu, G; Zaidi, S H

2007-03-15T23:59:59.000Z

384

Implantation conditions for diamond nanocrystal formation in amorphous silica  

SciTech Connect (OSTI)

We present a study of carbon ion implantation in amorphous silica, which, followed by annealing in a hydrogen-rich environment, leads to preferential formation of carbon nanocrystals with cubic diamond (c-diamond), face-centered cubic (n-diamond), or simple cubic (i-carbon) carbon crystal lattices. Two different annealing treatments were used: furnace annealing for 1 h and rapid thermal annealing for a brief period, which enables monitoring of early nucleation events. The influence of implanted dose and annealing type on carbon and hydrogen concentrations, clustering, and bonding were investigated. Rutherford backscattering, elastic recoil detection analysis, infrared spectroscopy, transmission electron microscopy, selected area electron diffraction, ultraviolet-visible absorption measurements, and Raman spectroscopy were used to study these carbon formations. These results, combined with the results of previous investigations on similar systems, show that preferential formation of different carbon phases (diamond, n-diamond, or i-carbon) depends on implantation energy, implantation dose, and annealing conditions. Diamond nanocrystals formed at a relatively low carbon volume density are achieved by deeper implantation and/or lower implanted dose. Higher volume densities led to n-diamond and finally to i-carbon crystal formation. This observed behavior is related to damage sites induced by implantation. The optical properties of different carbon nanocrystal phases were significantly different.

Buljan, Maja; Radovic, Iva Bogdanovic; Desnica, Uros V.; Ivanda, Mile; Jaksic, Milko [Ruder Boskovic Institute, P.O. Box 180, 10002 Zagreb (Croatia); Saguy, Cecile; Kalish, Rafi [Physics Department and Solid State Institute, Technion, Haifa 32000 (Israel); Djerdj, Igor [Department of Materials, Swiss Federal Institute of Technology (ETH) Zuerich, Wolfgang-Pauli-Str. 10, CH-8093 Zuerich (Switzerland); Tonejc, Andelka [Faculty of Science, Department of Physics, University of Zagreb, 10000 Zagreb (Croatia); Gamulin, Ozren [School of Medicine, Zagreb University, 10000 Zagreb (Croatia)

2008-08-01T23:59:59.000Z

385

Thickness controlled sol-gel silica films for plasmonic bio-sensing devices  

SciTech Connect (OSTI)

Plasmonics has recently received considerable interest due to its potentiality in many fields as well as in nanobio-technology applications. In this regard, various strategies are required for modifying the surfaces of plasmonic nanostructures and to control their optical properties in view of interesting application such as bio-sensing, We report a simple method for depositing silica layers of controlled thickness on planar plasmonic structures. Tetraethoxysilane (TEOS) was used as silica precursor. The control of the silica layer thickness was obtained by optimizing the sol-gel method and dip-coating technique, in particular by properly tuning different parameters such as pH, solvent concentration, and withdrawal speed. The resulting films were characterized via atomic force microscopy (AFM), Fourier-transform (FT) spectroscopy, and spectroscopic ellipsometry (SE). Furthermore, by performing the analysis of surface plasmon resonances before and after the coating of the nanostructures, it was observed that the position of the resonance structures could be properly shifted by finely controlling the silica layer thickness. The effect of silica coating was assessed also in view of sensing applications, due to important advantages, such as surface protection of the plasmonic structure.

Figus, Cristiana, E-mail: cristiana.figus@dsf.unica.it; Quochi, Francesco, E-mail: cristiana.figus@dsf.unica.it; Artizzu, Flavia, E-mail: cristiana.figus@dsf.unica.it; Saba, Michele, E-mail: cristiana.figus@dsf.unica.it; Marongiu, Daniela, E-mail: cristiana.figus@dsf.unica.it; Mura, Andrea; Bongiovanni, Giovanni [Dipartimento di Fisica - University of Cagliari, S.P. Km 0.7, I-09042 Monserrato (Canada) (Italy); Floris, Francesco; Marabelli, Franco; Patrini, Maddalena; Fornasari, Lucia [Dipartimento di Fisica - University of Pavia, Via Agostino Bassi 6, I-27100 Pavia (PV) (Italy); Pellacani, Paola; Valsesia, Andrea [Plasmore S.r.l. -Via Grazia Deledda 4, I-21020 Ranco (Vatican City State, Holy See) (Italy)

2014-10-21T23:59:59.000Z

386

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

SciTech Connect (OSTI)

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

387

Moisture sensor based on evanescent wave light scattering by porous sol-gel silica coating  

DOE Patents [OSTI]

An optical fiber moisture sensor that can be used to sense moisture present in gas phase in a wide range of concentrations is provided, as well techniques for making the same. The present invention includes a method that utilizes the light scattering phenomenon which occurs in a porous sol-gel silica by coating an optical fiber core with such silica. Thus, a porous sol-gel silica polymer coated on an optical fiber core forms the transducer of an optical fiber moisture sensor according to an embodiment. The resulting optical fiber sensor of the present invention can be used in various applications, including to sense moisture content in indoor/outdoor air, soil, concrete, and low/high temperature gas streams.

Tao, Shiquan; Singh, Jagdish P.; Winstead, Christopher B.

2006-05-02T23:59:59.000Z

388

Preparation and sintering of silica-doped zirconia by colloidal processing  

SciTech Connect (OSTI)

Silica-doped (SiO{sub 2} = 0--1.0 mass%) zirconia (3 mol% Y{sub 2}O{sub 3}-doped tetragonal ZrO{sub 2}) compacts are prepared from hetero-coagulated and well-dispersed suspensions by colloidal processing. The suspensions are consolidated by a pressure filtration technique. The green density of the compacts consolidated from the well-dispersed suspensions is higher than that from the hetero-coagulated suspensions. The lower density of the latter compacts is improved by a subsequent cold isostatic pressing (CIP) at 400 MPa. The sinterability of the compacts at 1,200 C is greatly affected by the amount of doped silica. The densification and grain growth are hindered by silica doping above 0.3 wt% at 1,200 C. All the compacts are densificated to a relative density of above 99% by sintering at 1,300 C for 2 h.

Uchikoshi, T.; Sakka, Y.; Ozawa, K.; Hiraga, K. [National Research Inst. for Metals, Tsukuba, Ibaraki (Japan)

1997-09-01T23:59:59.000Z

389

Self-Assembled Silica Nano-Composite Polymer Electrolytes: Synthesis, Rheology & Electrochemistry  

SciTech Connect (OSTI)

The ultimate objectives of this research are to understand the principles underpinning nano-composite polymer electrolytes (CPEs) and facilitate development of novel CPEs that are low-cost, have high conductivities, large Li+ transference numbers, improved electrolyte-electrode interfacial stability, yield long cycle life, exhibit mechanical stability and are easily processable. Our approach is to use nanoparticulate silica fillers to formulate novel composite electrolytes consisting of surface-modified fumed silica nano-particles in polyethylene oxides (PEO) in the presence of lithium salts. We intend to design single-ion conducting silica nanoparticles which provide CPEs with high Li+ transference numbers. We also will develop low-Mw (molecular weight), high-Mw and crosslinked PEO electrolytes with tunable properties in terms of conductivity, transference number, interfacial stability, processability and mechanical strength

Khan, Saad A.: Fedkiw Peter S.; Baker, Gregory L.

2007-01-24T23:59:59.000Z

390

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

SciTech Connect (OSTI)

Small angle neutron scattering (SANS) has been carried out to study the interaction of anionic silica nanoparticles (88 Å) with globular protein Bovine Serum Albumin (BSA) (M.W. 66.4 kD) in aqueous solution. The measurements have been carried out on fixed concentration (1 wt %) of Ludox silica nanoparticles with varying concentration of BSA (0–5 wt %) at pH7. Results show that silica nanoparticles and BSA coexist as individual entities at low concentration of BSA where electrostatic repulsive interactions between them prevent their aggregation. However, as the concentration of BSA increases (? 0.5 wt %), it induces the attractive depletion interaction among nanoparticles leading to finally their aggregation at higher BSA concentration (2 wt %). The aggregates are found to be governed by the diffusion limited aggregation (DLA) morphology of fractal nature having fractal dimension about 2.4.

Yadav, Indresh, E-mail: vkaswal@barc.gov.in; Aswal, V. K., E-mail: vkaswal@barc.gov.in [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai-400085 (India); Kohlbrecher, J. [Laboratory for Neutron Scattering, Paul Scherrer Institute, CH-5232 PSI Villigen Switzerland (Switzerland)

2014-04-24T23:59:59.000Z

391

A comparison of mechanical properties and scaling law relationships for silica aerogels and their organic counterparts  

SciTech Connect (OSTI)

Aerogels are a special class of open-cell foams derived from the supercritical extraction of highly crosslinked, inorganic or organic gels. The resultant materials have ultrafine cell/pore sizes (< 100 nm), high surface areas (350--1000m{sup 2}/g), and a microstructure composed of interconnected colloidal-like particles or polymeric chains with characteristic diameters of 10 nm. TEM and SAXS show that this microstructure is sensitive to variations in processing conditions that influence crosslinking chemistry and growth processes prior to gelation. Traditional silica aerogels are prepared via the hydrolysis and condensation of tetramethoxy silane (TMOS) or tetraethoxy silane (TEOS). Factors such as pH and the (H{sub 2}O)/(TMOS) ratio affect the microstructure of the dried aerogel. It is generally accepted that polymeric' silica aerogels result from acid catalysis while colloidal'silica aerogels result from base catalysis. Recently, Hrubesh and Tillotson developed a new condensed silica' procedure for obtaining silica aerogels with densities as low as 0.004g/cc, i.e. only 3{times} the density of air. Organic aerogels are formed from the aqueous, polycondensation of (1) resorcinol/formaldehyde or (2) melamine/formaldehyde. The microstructure of the resorcinol-formaldehyde (RF) aerogels is dictated by the amount of base catalyst used in the sol-gel polymerization. In addition, these materials can be pyrolyzed in an inert atmosphere to form vitreous carbon aerogels. Melamine- formaldehyde (MF) aerogels that are both colorless and transparent are only formed under acidic conditions (i.e. pH = 1--2). In this paper, the microstructural dependence and scaling law relationships for the compressive modulus of silica, carbon, RF, and MF aerogels will be discussed in detail. 17 refs., 1 fig.

Pekala, R.W.; Hrubesh, L.W.; Tillotson, T.M.; Alviso, C.T.; Poco, J.F.; LeMay, J.D.

1990-08-01T23:59:59.000Z

392

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

393

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

E-Print Network [OSTI]

Ultra-large bandwidth hollow-core guiding in all-silica Bragg fibers with nano-supports Guillaume 420, 650-653 (2002). 7. C. M. Smith et al., "Low-loss hollow-core silica/air photonic bandgap fibre yong@its.caltech.edu. Abstract: We demonstrate a new class of hollow-core Bragg fibers

Huang, Yanyi

394

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

E-Print Network [OSTI]

Am J Epidemiol . Author manuscript Page /1 10 Aluminum and silica in drinking water and the risk associations between exposure to aluminum or silica from drinking water and risk of cognitive decline, dementia of dementia, aged' 65 years and over living in 91 civil drinking water areas in Southern France. Two measures

Paris-Sud XI, Université de

395

Structure and Dynamics of Acetonitrile Confined in a Silica Nanopore Liwen Cheng, Joseph A. Morrone, and B. J. Berne*  

E-Print Network [OSTI]

Structure and Dynamics of Acetonitrile Confined in a Silica Nanopore Liwen Cheng, Joseph A. Morrone York 10027, United States ABSTRACT: Acetonitrile confined in silica nanopores with surfaces of varying. It is found that acetonitrile orders into bilayer like structures near the surface, in agreement with prior

Berne, Bruce J.

396

Water, chloroform, acetonitrile, and atrazine adsorption to the amorphous silica surface studied by vibrational sum frequency generation spectroscopy  

E-Print Network [OSTI]

Water, chloroform, acetonitrile, and atrazine adsorption to the amorphous silica surface studied the air­silica interface before, during, and after adsorption of water, chloroform, acetonitrile the compounds. Adsorption of chloro- form and acetonitrile was weaker compared to water. Binding to the surface

397

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

E-Print Network [OSTI]

(Type I) from Lafarge Corp. (Southfield, MI). The silica fume (Elkem Materials, Inc., Pittsburgh, PA, EMS 965) was used in the amount of 15% by weight of cement. Surface treatment of silica fume Printed in the USA. All rights reserved 0008-8846/98 $19.00 .00 PII S0008-8846(98)00017-9 493 #12;effect

Chung, Deborah D.L.

398

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

SciTech Connect (OSTI)

In enhanced geothermal systems (EGS) the reservoir permeability is often enhanced or created using hydraulic fracturing. In hydraulic fracturing, high fluid pressures are applied to confined zones in the subsurface usually using packers to fracture the host rock. This enhances rock permeability and therefore conductive heat transfer to the circulating geothermal fluid (e.g. water or supercritical carbon dioxide). The ultimate goal is to increase or improve the thermal energy production from the subsurface by either optimal designs of injection and production wells or by altering the fracture permeability to create different zones of circulation that can be exploited in geothermal heat extraction. Moreover, hydraulic fracturing can lead to the creation of undesirable short-circuits or fast flow-paths between the injection and extraction wells leading to a short thermal residence time, low heat recovery, and thus a short-life of the EGS. A potential remedy to these problems is to deploy a cementing (blocking, diverting) agent to minimize short-cuts and/or create new circulation cells for heat extraction. A potential diverting agent is the colloidal silica by-product that can be co-produced from geothermal fluids. Silica gels are abundant in various surface and subsurface applications, yet they have not been evaluated for EGS applications. In this study we are investigating the benefits of silica gel deployment on thermal response of an EGS, either by blocking short-circuiting undesirable pathways as a result of diverting the geofluid to other fractures; or creating, within fractures, new circulation cells for harvesting heat through newly active surface area contact. A significant advantage of colloidal silica is that it can be co-produced from geothermal fluids using an inexpensive membrane-based separation technology that was developed previously using DOE-GTP funding. This co-produced silica has properties that potentially make it useful as a fluid diversion agent for subsurface applications. Colloidal silica solutions exist as low-viscosity fluids during their “induction period” but then undergo a rapid increase in viscosity (gelation) to form a solid gel. The length of the induction period can be manipulated by varying the properties of the solution, such as silica concentration and colloid size. We believe it is possible to produce colloidal silica gels suitable for use as diverting agents for blocking undesirable fast-paths which result in short-circuiting the EGS once hydraulic fracturing has been deployed. In addition, the gels could be used in conventional geothermal fields to increase overall energy recovery by modifying flow.

Hunt, Jonathan

2013-01-31T23:59:59.000Z

399

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

DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

In enhanced geothermal systems (EGS) the reservoir permeability is often enhanced or created using hydraulic fracturing. In hydraulic fracturing, high fluid pressures are applied to confined zones in the subsurface usually using packers to fracture the host rock. This enhances rock permeability and therefore conductive heat transfer to the circulating geothermal fluid (e.g. water or supercritical carbon dioxide). The ultimate goal is to increase or improve the thermal energy production from the subsurface by either optimal designs of injection and production wells or by altering the fracture permeability to create different zones of circulation that can be exploited in geothermal heat extraction. Moreover, hydraulic fracturing can lead to the creation of undesirable short-circuits or fast flow-paths between the injection and extraction wells leading to a short thermal residence time, low heat recovery, and thus a short-life of the EGS. A potential remedy to these problems is to deploy a cementing (blocking, diverting) agent to minimize short-cuts and/or create new circulation cells for heat extraction. A potential diverting agent is the colloidal silica by-product that can be co-produced from geothermal fluids. Silica gels are abundant in various surface and subsurface applications, yet they have not been evaluated for EGS applications. In this study we are investigating the benefits of silica gel deployment on thermal response of an EGS, either by blocking short-circuiting undesirable pathways as a result of diverting the geofluid to other fractures; or creating, within fractures, new circulation cells for harvesting heat through newly active surface area contact. A significant advantage of colloidal silica is that it can be co-produced from geothermal fluids using an inexpensive membrane-based separation technology that was developed previously using DOE-GTP funding. This co-produced silica has properties that potentially make it useful as a fluid diversion agent for subsurface applications. Colloidal silica solutions exist as low-viscosity fluids during their “induction period” but then undergo a rapid increase in viscosity (gelation) to form a solid gel. The length of the induction period can be manipulated by varying the properties of the solution, such as silica concentration and colloid size. We believe it is possible to produce colloidal silica gels suitable for use as diverting agents for blocking undesirable fast-paths which result in short-circuiting the EGS once hydraulic fracturing has been deployed. In addition, the gels could be used in conventional geothermal fields to increase overall energy recovery by modifying flow.

Hunt, Jonathan

400

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

DOE Patents [OSTI]

A silica embedded metal hydride composition and a method for making such a composition. The composition is made via the following process: A quantity of fumed silica is blended with water to make a paste. After adding metal hydride particles, the paste is dried to form a solid. According to one embodiment of the invention, the solid is ground into granules for use of the product in hydrogen storage. Alternatively, the paste can be molded into plates or cylinders and then dried for use of the product as a hydrogen filter. Where mechanical strength is required, the paste can be impregnated in a porous substrate or wire network.

Heung, Leung K. (Aiken, SC)

1999-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "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

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

SciTech Connect (OSTI)

An investigation has been made of the decomposition of cumyl hydroperoxide (CHP) in the presence of silica-based sulphocationites in a flow-type system. It was established that the given specimens are effective catalysts for the decomposition of CHP into phenol and acetone. It was shown that, in the course of the process, no irreversible poisoning of the surface of the catalyst by the products of CHP decomposition occurs. Data of chromatographic analysis of the products of CHP decomposition in the presence of sulphuric acid and silica-based sulphocationites are given.

Shelpakova, N.A.; Ioffa, A.F.

1993-12-31T23:59:59.000Z

402

Bulk and surface laser damage of silica by picosecond and nanosecond pulses at 1064 nm  

SciTech Connect (OSTI)

We measured bulk and surface dielectric breakdown thresholds of pure silica for 14 ps and 8 ns pulses of 1064 nm light. The thresholds are sharp and reproducible. For the 8 ns pulses the bulk threshold irradiance is 4.75 {+-} 0.25 kW/{mu}m{sup 2}. The threshold is approximately three times higher for 14 ps pulses. For 8 ns pulses the input surface damage threshold can be made equal to the bulk threshold by applying an alumina or silica surface polish.

Smith, Arlee V.; Do, Binh T

2008-09-10T23:59:59.000Z

403

Synthesis, Characterization, and Catalytic Function of Novel...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Characterization, and Catalytic Function of Novel Highly Dispersed Tungsten Oxide Catalysts on Mesoporous Silica . Synthesis, Characterization, and Catalytic Function of Novel...

404

Synthesis of Nanodispersed Oxides of Vanadium, Titanium, Molybdenum...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Nanodispersed Oxides of Vanadium, Titanium, Molybdenum, and Tungsten on Mesoporous Silica using Atomic Layer Synthesis of Nanodispersed Oxides of Vanadium, Titanium, Molybdenum,...

405

Hydrogen Storage Materials Workshop Proceedings, August 14th...  

Broader source: Energy.gov (indexed) [DOE]

molecular sieve MCM-48 impregnated with sucrose and then pyrolyzed. * Silica dioxide aerogels and xerogels have not been explored as hydrogen storage materials. * Other mesoporous...

406

Uranium and Strontium Batch Sorption and Diffusion Kinetics into...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Uranium and Strontium Batch Sorption and Diffusion Kinetics into Mesoporous Silica Friday, February 27, 2015 Figure 1 Figure 1. Transmission electron microscopy images of (A)...

407

Microsoft Word - U(VI)andSr(II)BatchSorption bh  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

C and D point towards some of the precipitates. Uranium and Strontium Batch Sorption and Diffusion Kinetics into Mesoporous Silica Important reactive phenomena that affect the...

408

Electron-Irradiation Induced Nanocrystallization of Pb(II) in Silica Gels Prepared in High Magnetic Field  

E-Print Network [OSTI]

In a previous study, structure of silica gels prepared in a high magnetic field was investigated. While a direct application of such anisotropic silica gels is for an optical anisotropic medium possessing chemical resistance, we show here their possibility of medium in materials processing. In this direction, for example, silica hydrogels have so far been used as media of crystal growth. In this paper, as opposed to the soft-wet state, dried silica gels have been investigated. We have found that lead (II) nanocrystallites were formed induced by electron irradiation to lead (II)-doped dried silica gels prepared in a high magnetic field such as B = 10 T. Hydrogels made from a sodium metasilicate solution doped with lead (II) acetate were prepared. The dried specimens were irradiated by electrons in a transmission electron microscope environment. Electron diffraction patterns indicated the crystallinity of lead (II) nanocrystallites depending on B. An advantage of this processing technique is that the crystallin...

Kaito, Takamasa; Kaito, Chihiro

2015-01-01T23:59:59.000Z

409

Effect of Carbon Black and Silica Fillers in Elastomer Blends Yimin Zhang, S. Ge, B. Tang, T. Koga, M. H. Rafailovich,*, J. C. Sokolov,  

E-Print Network [OSTI]

, the effect of carbon black is offset by silica fillers. Introduction Fillers exist in a variety of systemsEffect of Carbon Black and Silica Fillers in Elastomer Blends Yimin Zhang, S. Ge, B. Tang, T. Koga January 30, 2001 ABSTRACT: The effects of carbon black and pyrogeneous silica fillers on the interfacial

410

Ion irradiation damage in k-doped silica probed by the Er3+ luminescence lifetime at 1.535 pm4  

E-Print Network [OSTI]

irradiation.' Furthermore, silica-basedop- tical fibers are the standard in telecommunicationtechnol- ogy the effectof MeV ion irradiation damage on the optical propertiesof Er-doped silica films is studied. Erbium-doped silica glasshas recently attracted attention becauseof its use in optical fiber amplifiers.5'6Erbium

Polman, Albert

411

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

SciTech Connect (OSTI)

We have assessed the feasibility of carrying out time- and wavelength-resolved laser-induced fluorescence measurements of radiation damage in glassy silica. The consequences of alpha decay of Es-253 in LaPO{sub 4} nanophases embedded in silica were probed based on excitation of 5f states of Cm{sup 3+}, Bk{sup 3+}, and Es{sup 3+} ions. The recorded emission spectra and luminescence decays showed that alpha decay of Es-253 ejected Bk-249 decay daughter ions into the surrounding silica and created radiation damage within the LaPO{sub 4} nanophases. This conclusion is consistent with predictions of an ion transport code commonly used to model ion implantation. Luminescence from the {sup 6}D{sub 7/2} state of Cm{sup 3+}was used as an internal standard. Ion-ion energy transfer dominated the dynamics of the observed emitting 5f states and strongly influenced the intensity of observed spectra. In appropriate sample materials, laser-induced fluorescence provides a powerful method for fundamental investigation of alpha-induced radiation damage in silica.

Beitz, James V. [Chemistry Division, 9700 South Cass Avenue, Argonne National Laboratory, Argonne, IL 60439-4831 (United States)]. E-mail: beitz@anl.gov; Williams, C.W. [Chemistry Division, 9700 South Cass Avenue, Argonne National Laboratory, Argonne, IL 60439-4831 (United States); Hong, K.-S. [Chemistry Division, 9700 South Cass Avenue, Argonne National Laboratory, Argonne, IL 60439-4831 (United States); Liu, G.K. [Chemistry Division, 9700 South Cass Avenue, Argonne National Laboratory, Argonne, IL 60439-4831 (United States)

2005-02-15T23:59:59.000Z

412

Fluorescent silica colloids for study and visualization of skin care products  

E-Print Network [OSTI]

due to long exposures to cold and dry air (7). Different skin care products are used to hy- drate dryFluorescent silica colloids for study and visualization of skin care products Swaminathan Iyer: The efficacy of skin care products depends on the time and dynamics of their absorbance by the skin, and its

Sokolov, Igor

413

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

SciTech Connect (OSTI)

Superhydrophobic silica (SHS) powders are being evaluated as a potential additive to the polyurethane topcoats used in Chemical Agent Resistant Coating (CARC) systems, with the goal of improving water repellency and corrosion protection characteristics. The current generation of CARC topcoats is already highly loaded with solids, and thus there is a premium on minimization of the total SHS powder required to achieve the desired properties. Therefore, efficient surface modification of the silica and proper dispersion in the coating will be required. The effect of a dispersant on the surface modification of silica particles by chlorosilanes was addressed in this study. The properties of various SHS powders were characterized by thermogravimetric analysis and mass spectroscopy. Correlations between powder modification conditions and the ultimate effects of the modified particles on hydrophobicity of CARC topcoats were assessed. The use of contact and rolling angle measurements along with scanning electron microscopy are discussed as they pertain to the ability to quantify the effects of modified silicas on corrosion prevention coatings. Furthermore, a systematic approach to modifying and testing both powders and top coats of corrosion prevention systems is presented.

Armstrong, Beth L [ORNL] [ORNL; Pawel, Steven J [ORNL] [ORNL; Hunter, Scott Robert [ORNL] [ORNL; Haynes, James A [ORNL] [ORNL; Hillesheim, Daniel A [ORNL] [ORNL

2013-01-01T23:59:59.000Z

414

Density hysteresis of heavy water confined in a nanoporous silica matrix  

E-Print Network [OSTI]

A neutron scattering technique was developed to measure the density of heavy water confined in a nanoporous silica matrix in a temperature-pressure range, from 300 to 130 K and from 1 to 2,900 bars, where bulk water will ...

Faraone, Antonio

415

Effectiveness of cabs for dust and silica control on mobile mining equipment  

SciTech Connect (OSTI)

The Mine Safety and Health Administration (MSHA) has conducted a study to evaluate the effectiveness of cabs for controlling silica dust exposure during operation of mobile mining equipment. This study focused on bulldozers, front-end loaders and haul trucks, was conducted at surface coal mining operations and underground metal and nonmetal mining operations. Each piece of equipment tested was equipped with a cab. The vehicles sampled were from a range of manufacturers having different types of filter media and air intake configurations. The purpose of this study was to determine the reduction of dust and silica exposure that could be achieved through the use of a well-maintained cab. For each piece of equipment, dust and silica concentrations inside and outside the cab were determined and compared. In some cases, filtration efficiencies could be calculated. A properly designed environmental cab is sealed, has an intake air filtration system, and a heating and cooling system. Cabs should have good seals around the doors and windows. Factors such as cab pressurization filtration systems, filter media, and maintenance practices were also examined. In some cases, dust and silica reduction of 90 to 95% were observed.

Garcia, J.J.; Gresh, R.E.; Gareis, M.B.; Haney, R.A.

1999-07-01T23:59:59.000Z

416

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

E-Print Network [OSTI]

Silica Supported Single-Walled Carbon Nanotubes as a Modifier in Polyethylene Composites Neal D. Mc.interscience.wiley.com). ABSTRACT: Composites have been made from single- wall carbon nanotubes in a polyethylene (PE) matrix: additives; composites; conducting polymers; nanocomposites; polyethylene INTRODUCTION Polyethylene (PE

Resasco, Daniel

417

E-Print Network 3.0 - amorphous silica dissolution Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Microscopic Surface Processes Across Summary: No electrolytes 0.1 -2.3 670 0.0167 M CaCl2 0.65 -0.4 44 0.0167 M CaCl2 0.1 -2.3 4 12;DISSOLUTION OF SILICA... Kinetics of...

418

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

419

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

E-Print Network [OSTI]

. Micropore surface area and micropore volume are reduced by about 19% and 18%, respectively, indicating some micropores of ZSM-5 are blocked on binding with silica. SiO2-bound ZSM-5 catalysts have less catalytic activity for butane transformation (cracking...

Wu, Xianchun

2004-09-30T23:59:59.000Z

420

Characterization of the intrinsic strength between epoxy and silica using a multiscale approach  

E-Print Network [OSTI]

, we report a model to predict the intrinsic strength between organic and inorganic materials, based energy surface between attached and detached states of the bonded system and scaled up to incorporate readily in many other polymers. Silica, commonly found material in nature in the form of sand or quartz

Buehler, Markus J.

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

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

E-Print Network [OSTI]

1 MODELING THE MEAN INTERACTION FORCES BETWEEN POWDER PARTICLES. APPLICATION TO SILICA GEL-MAGNESIUM) particles (d50 = 55 µm) were coated with fine invited particles of magnesium stearate (MS, d50 = 4.6 µm. Interaction forces between the material attached to the cantilever (Magnesium Stearate MS) and the surface

Paris-Sud XI, Université de

422

Fluorocarbon plasma etching and profile evolution of porous low-dielectric-constant silica  

E-Print Network [OSTI]

of PS, a feature profile model has been integrated with a plasma equipment model. To focus on issuesFluorocarbon plasma etching and profile evolution of porous low-dielectric-constant silica Arvind silicon dioxide PS is one such material. To address scaling issues during fluorocarbon plasma etching

Kushner, Mark

423

Plasticity-induced structural anisotropy of silica glass C. L. Rountree1  

E-Print Network [OSTI]

Plasticity-induced structural anisotropy of silica glass C. L. Rountree1 , D. Vandembroucq2 , M anisotropic structure after extended shear plastic flow. This anisotropy which survives for an un- stressed tetrahedra microstructure remains mostly unaltered. PACS numbers: 62.20.F, 81.05.Kf Plasticity of amorphous

Boyer, Edmond

424

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

E-Print Network [OSTI]

. The silica fume (Elkem Materials, Inc., Pittsburgh, PA, EMS 965) was used in the amount of 15% by weight 14260-4400, USA (Received February 6, 1998; in final form June 26, 1998) ABSTRACT The addition of sand. 10, pp. 1353­1356, 1998 Copyright © 1998 Elsevier Science Ltd Printed in the USA. All rights reserved

Chung, Deborah D.L.

425

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

E-Print Network [OSTI]

the effect of humidity on the kinetics of subcritical crack growth in high strength optical fibers that the rate of subcritical crack growth is given by dc dt ¼ A exp n KI KIC ; ð1� where A and n are fatigue by assuming a simple chemical kinetics model for fatigue in which the reaction rate between water and silica

Matthewson, M. John

426

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

E-Print Network [OSTI]

, NJ 08 854-8065 ABSTRACT Subcritical crack growth in fused silica can be modeled as a stress assisted chemical reaction between water and strained bonds at the crack tip. The stress influences the crack growth which has been most commonly used for brittle ceramic materials is the well-known subcritical crack

Matthewson, M. John

427

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

E-Print Network [OSTI]

of stress, temperature and activity of the corroding species (e.g. water). A power law degradation kinetics the degradation depends on the applied stress. Subcritical Crack Growth Model The reliability of silica optical fiber under stress is usually described by the subcritical crack growth model. It is assumed

Matthewson, M. John

428

THE EFFECT OF TEMPERATURE AND UNIAXIAL PRESSURE ON THE DENSIFICATION BEHAVIOR OF SILICA AEROGEL GRANULES  

SciTech Connect (OSTI)

Materials are being developed in U.S. for the removal and immobilization of iodine from gaseous products of nuclear fuel reprocessing in support of the Fuel Cycle Technology Separations and Waste Forms Campaign. The silver-functionalized silica aerogel proved to be an excellent candidate for this treatment because of its high selectivity and sorption capacity for radioiodine and its possible conversion to a durable silica-based waste form. The present study investigated with nitrogen sorption and helium pycnometry the effect of pressureless isothermal sintering at temperatures of 900-1400°C for 2.5-90 min or isothermal hot-pressing at 1200°C for 2.5 min on densification of raw and silver-functionalized silica aerogel granules. Rapid sintering was observed at 1050 and 1200°C. Only 15 min of pressureless sintering at 1200°C resulted in almost complete densification. The macropores disappeared, surface area decreased from 1114 m2/g to 25 m2/g, pore volume from 7.41 cm3/g to 0.09 cm3/g, and adsorption pore size from 18.7 to 7 nm. The skeletal density of sintered granules was similar to the bulk density of amorphous silica (2.2 g/cm3). The hot-pressing accelerated the sintering process, decreasing significantly the pore size and volume.

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

2012-10-01T23:59:59.000Z

429

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

E-Print Network [OSTI]

Acoustic and Thermal Characterization of Oil Migration, Gas Hydrates Formation and Silica Rights Reserved #12;ABSTRACT Acoustic and Thermal Characterization of Oil Migration, Gas Hydrates-A to Opal-CT, the formation of gas hydrates, fluid substitution in hydrocarbon reservoirs, and fluid

Guerin, Gilles

430

Nanotube Quality Control NANOMATERIALS  

E-Print Network [OSTI]

on device performance and reliability. For example, the presence of residual catalyst particles can alter measure of the types of carbons present. The residual mass provides an estimate of the metal fraction of coating techniques can be used to deposit the nanotube material, including drop casting, spin coating

431

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

432

Radiation damage tolerant nanomaterials  

E-Print Network [OSTI]

Designing a material from the atomic level to achieve a tailored response in extreme conditions is a grand challenge in materials research. Nanostructured metals and composites provide a path to this goal because they ...

Beyerlein, I.J.

433

Metrology for Sustainable Nanomaterials  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious RankCombustion | Department of EnergyDevelopmentTechnologies |CharlesDepartment ofChemistry |Institute of

434

Sustainable Nanomaterials Industry Perspective  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious RankCombustion |Energy Usage »of Energy Strain Rate4SuperhardSuspect andCoaches Aim Industry Perspective

435

BNL | CFN: Electronic Nanomaterials  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-Series to someone6 M. Babzien, I. Ben-Zvi, P. Catravas, J. M.

436

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

SciTech Connect (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

437

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

SciTech Connect (OSTI)

The mixed oxidation state (3+/4+) of ceria nanoparticles of smaller sizes make them attractive materials for their catalytic antioxidant biological properties. However the unmodified smaller ceria nanoparticles are limited in their use due to particles agglomeration and reduced surface chemical reactivity in the solutions used to disperse the nanoparticles. This work describes an effort to stabilize small ceria nanoparticles, retaining their desired activity, on a larger stable silica support. The ceria nanoparticles attached to silica was synthesized by a solution synthesis technique in which the surface functional groups of silica nanoparticles were found to be essential for the formation of smaller ceria nanoparticles. The surface chemical and vibrational spectroscopy analysis revealed cerium–silicate (Ce-O-Si) covalent bond linkage between silica and cerium oxide nanoparticles. The colloidal properties (agglomerate particle size and suspension stability) of ceria attached to silica was significantly improved due to inherent physico-chemical characteristics of silica against random collision and gravitation settling as opposed to unmodified ceria nanoparticles in solution. The bio-catalytic activity of ceria nanoparticles in the 3+ oxidation state was not found to be limited by attachment to the silica support as measured by free radical scavenging activity in different biological media conditions.

Munusamy, Prabhakaran; Sanghavi, Shail P.; Varga, Tamas; Thevuthasan, Suntharampillai

2014-01-21T23:59:59.000Z

438

The effect of the distance between acidic site and basic site immobilized on mesoporous solid on the activity in catalyzing aldol condensation  

SciTech Connect (OSTI)

Acid-base bifunctional heterogeneous catalysts containing carboxylic and amine groups, which were immobilized at defined distance from one another on the mesoporous solid were synthesized by immobilizing lysine onto carboxyl-SBA-15. The obtained materials were characterized by X-ray diffraction (XRD), N{sub 2} adsorption, Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron micrographs (SEM), transmission electron micrographs (TEM), elemental analysis, and back titration. Proximal-C-A-SBA-15 with a proximal acid-base distance was more active than maximum-C-A-SBA-15 with a maximum acid-base distance in aldol condensation reaction between acetone and various aldehydes. It appears that the distance between acidic site and basic site immobilized on mesoporous solid should be an essential factor for catalysis optimization. -- Graphical abstract: Proximal-C-A-SBA-15 with a proximal acid-base distance and maximum-C-A-SBA-15 with a maximum acid-base distance were synthesized by immobilizing lysine onto carboxyl-SBA-15. Display Omitted Research highlights: {yields} Proximal-C-A-SBA-15 with a proximal acid-base distance. {yields} Maximum-C-A-SBA-15 with a maximum acid-base distance. {yields} Compared to maximum-C-A-SBA-15, proximal-C-A-SBA-15 was more active toward aldol condensation reaction between acetone and various aldehydes.

Yu Xiaofang [College of Chemistry, Jilin University, Jiefang Road 2519, Changchun 130023 (China); Yu Xiaobo [China Pharmaceutical University, Nanjing 210009 (China); Wu Shujie; Liu Bo; Liu Heng [College of Chemistry, Jilin University, Jiefang Road 2519, Changchun 130023 (China); Guan Jingqi, E-mail: guanjq@jlu.edu.c [College of Chemistry, Jilin University, Jiefang Road 2519, Changchun 130023 (China); Kan Qiubin, E-mail: catalysischina@yahoo.com.c [College of Chemistry, Jilin University, Jiefang Road 2519, Changchun 130023 (China)

2011-02-15T23:59:59.000Z

439

Synthesis and Characterization of Mesostructured Tin Oxide with Crystalline  

E-Print Network [OSTI]

synthesis of silica-based mesoporous molecular materials (MCM-41) with uni- formly sized pores,1 routes. The obtained mesoporous metal oxide materials usually consist of amorphous walls, although be of industrial interest. Recently, a mesoporous phase based on SnO2 has been successfully synthesized by using

Qi, Limin

440

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

E-Print Network [OSTI]

Further exploration of hybrid organic/inorganic composites (polyurethane based with inorganic material sodium silica polyphosphate) properties with mechanical relaxometer gives ability to analyze microstructure of such materials in terms of chain reptation tubes filler's fractal aggregates and stress amplification.

V. O. Dupanov; S. M. Ponomarenko

2014-10-31T23:59:59.000Z

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

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

E-Print Network [OSTI]

THE ROLE OF EFFECTIVE STRESS ON SILICA SOLUBILITY AND PRESSURE SOLUTION: AN EXPERIMENTAL INVESTIGATION IN A FLOW-THROUGH SYSTEM A Thesis by BRIAN PATRICK ELIAS Submitted to the Office of Graduate Studies of Texas A&M University in partial... fulfillment of the requirements for the degree of MASTER OF SCIENCE May 1989 Major Subject: Geology THE ROLE OF EFFECTIVE STRESS ON SILICA SOLUBILITY AND PRES SURE SOLUTION: AN EXPERIMENTAL INVESTIGATION IN A FLOW-THROUGH SYSTEM A Thesis by BRIAN...

Elias, Brian Patrick

2012-06-07T23:59:59.000Z

442

Mesoporous Co{sub 3}O{sub 4} nanostructured material synthesized by one-step soft-templating: A magnetic study  

SciTech Connect (OSTI)

A combined magnetization and zero-field {sup 59}Co spin-echo nuclear magnetic resonance (NMR) study has been carried out on one member of a recently developed class of highly ordered mesoporous nanostructured materials, mesoporous Co{sub 3}O{sub 4} (designated UCT-8, University of Connecticut, mesoporous materials). The material was synthesized using one-step soft-templating by an inverse micelles packing approach. Characterization of UCT-8 by powder x-ray diffraction and electron microscopy reveals that the mesostructure consists of random close-packed Co{sub 3}O{sub 4} nanoparticles ??12?nm in diameter. The N{sub 2} sorption isotherm for UCT-8, which is type IV with a type H1 hysteresis loop, yields a 134 m{sup 2}/g BET surface area and a 7.7?nm BJH desorption pore diameter. The effect of heat treatment on the structure is discussed. The antiferromagnetic Co{sub 3}O{sub 4} nanoparticles have a Néel temperature T{sub N}?=?27?K, somewhat lower than the bulk. A fit to the Curie-Weiss law over the temperature range 75?K???T???300?K yields an effective magnetic moment of ?{sub eff}?=?4.36??{sub B} for the Co{sup 2+} ions, indicative of some orbital contribution, and a Curie-Weiss temperature ??=??93.5?K, consistent with antiferromagnetic ordering. The inter-sublattice and intra-sublattice exchange constants for the Co{sup 2+} ions are J{sub 1}/k{sub B}?=?(?)4.75?K and J{sub 2}/k{sub B}?=?(?)0.87?K, respectively, both corresponding to antiferromagnetic coupling. The presence of uncompensated surface spins is observed below T{sub N} with shifts in the hysteresis loops, i.e., an exchange-bias effect. The {sup 59}Co NMR spectrum for UCT-8, which is attributed to Co{sup 2+} ions at the tetrahedral A sites, is asymmetrically broadened with a peak at ?55?MHz (T?=?4.2?K). Since there is cubic symmetry at the A-sites, the broadening is indicative of a magnetic field distribution due to the uncompensated surface spins. The spectrum is consistent with antiferromagnetically ordered particles that are nanometer in size and single domain.

Poyraz, Altug S.; Kuo, Chung-Hao; Li, Nan [Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269-3060 (United States); Hines, William A., E-mail: wahines@phys.uconn.edu; Perry, David M. [Department of Physics, University of Connecticut, Storrs, Connecticut 06269-3046 (United States); Suib, Steven L. [Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269-3060 (United States); Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269-3136 (United States)

2014-03-21T23:59:59.000Z

443

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

SciTech Connect (OSTI)

Adsorption of carbon monoxide at room temperature (0.1 to 50 Torr) on silica-supported copper oxide was studied by infrared spectroscopy. Catalysts were prepared by deposition-precipitation or impregnation. After calcination two types of adsorbed CO were identified showing absorption bands at 2136 +- 3 and 2204 +- 1 cm/sup -1/, which are ascribed to CO adsorbed on copper(II) oxide and on isolated copper(II) ions in the silica surface, respectively. Reduction and reoxidation removed the band at 2204 cm/sup -1/ with all samples and raised the intensity of the 2136-cm/sup -1/ band with the precipitated catalysts but not with the impregnation catalyst. Evidence is brought forward that the isolated copper ions are mobilized during reduction and generate new copper (oxide) surface. The change in background transmission of the samples could be used to obtain further information about the interaction of O/sub 2/ and CO with copper oxide.

De Jong, K.P.; Geus, J.W.; Joziasse, J.

1980-10-01T23:59:59.000Z

444

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

SciTech Connect (OSTI)

The laser oscillations from 1553 up to 1603 nm have been demonstrated in Er/sup 3 +/-doped silica fibers with a doping rate of 2500 ppm. Wide changes in laser oscillation wavelengths are due to broad splitting of the upper sublevels in the /sup 4/I/sub 152/ manifold, caused by the random structure of the silica matrix. It has been shown that unpumped parts of the Er/sup 3 +/ ions in the end pumped fiber laser configuration play an important role in the wavelength changes of the laser oscillation. For an absorbed pump power of 320 mW at 514 nm, output power of 0.5 mW was obtained at 1603 nm.

Kimura, Y.; Nakazawa, M.

1988-07-15T23:59:59.000Z

445

Gamma radiation-induced refractive index change in Ge- and N-doped silica  

SciTech Connect (OSTI)

We measured the change of the refractive index over a wide wavelength range in Ge- and N-doped high purity (fiber optics grade) silica glasses subjected to gamma irradiation. The radiation-induced change of the refractive index tends to be greater in the infrared part of the spectrum compare to the values measured in the UV-visible part of the spectrum. By means of the Kramers-Kronig relations, we estimate that a weak broadening of the optical vibration band of the silica network adds to this effect. The paper also discusses the difference observed in the spectral behavior of the induced refractive index change for both types of doped glass.

Brichard, Benoit [SCK-CEN-Belgian Nuclear Research Center, Boeretang 200, 2400 Mol (Belgium); Butov, Oleg V.; Golant, Konstantin M. [Fiber Optics Research Center, Russian Academy of Sciences, Vavilov Street 38, 119991 Moscow (Russian Federation); Fernandez Fernandez, Alberto [Masterminds Ltd., rue du Temple 40, CH-2800 Delemont (Switzerland)

2008-03-01T23:59:59.000Z

446

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

447

High-Q silica zipper cavity for optical radiation pressure driven MOMS switch  

SciTech Connect (OSTI)

We design a silica zipper cavity that has high optical and mechanical Q (quality factor) values and demonstrate numerically the feasibility of a radiation pressure driven micro opto-mechanical system (MOMS) directional switch. The silica zipper cavity has an optical Q of 4.0 × 10{sup 4} and an effective mode volume V{sub mode} of 0.67?{sup 3} when the gap between two cavities is 34 nm. The mechanical Q (Q{sub m}) is determined by thermo-elastic damping and is 2.0 × 10{sup 6} in a vacuum at room temperature. The opto-mechanical coupling rate g{sub OM} is as high as 100 GHz/nm, which allows us to move the directional cavity-waveguide system and switch 1550-nm light with 770-nm light by controlling the radiation pressure.

Tetsumoto, Tomohiro; Tanabe, Takasumi, E-mail: takasumi@elec.keio.ac.jp [Department of Electronics and Electrical Engineering, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi Kohoku, Yokohama 223-8522 (Japan)

2014-07-15T23:59:59.000Z

448

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

SciTech Connect (OSTI)

A combination of electron diffraction and infrared reflectance measurements shows that synthetic silica transforms partially into stishovite under high-intensity (GW/cm2) laser irradiation, probably by the formation of a dense ionized plasma above the silica surface. During the transformation the silicon coordination changes from four-fold to six-fold and the silicon-oxygen bond changes from mostly covalent to mostly ionic, such that optical properties of the transformed material differ significantly from those of the original glass. This phase transformation offers one suitable mechanism by which laser-induced damage grows catastrophically once initiated, thereby dramatically shortening the service lifetime of optics used for high-power photonics applications such as inertial confinement fusion.

Salleo, Alberto; Taylor, Seth T.; Martin, Michael C.; Panero, Wendy R.; Jeanloz, Raymond; Genin, Francois Y.; Sands, Timothy

2002-05-31T23:59:59.000Z

449

Experimental stress–strain analysis of tapered silica optical fibers with nanofiber waist  

SciTech Connect (OSTI)

We experimentally determine tensile force–elongation diagrams of tapered optical fibers with a nanofiber waist. The tapered optical fibers are produced from standard silica optical fibers using a heat and pull process. Both, the force–elongation data and scanning electron microscope images of the rupture points indicate a brittle material. Despite the small waist radii of only a few hundred nanometers, our experimental data can be fully explained by a nonlinear stress–strain model that relies on material properties of macroscopic silica optical fibers. This is an important asset when it comes to designing miniaturized optical elements as one can rely on the well-founded material characteristics of standard optical fibers. Based on this understanding, we demonstrate a simple and non-destructive technique that allows us to determine the waist radius of the tapered optical fiber. We find excellent agreement with independent scanning electron microscope measurements of the waist radius.

Holleis, S.; Hoinkes, T.; Wuttke, C.; Schneeweiss, P.; Rauschenbeutel, A. [Vienna Center for Quantum Science and Technology, TU Wien—Atominstitut, Stadionallee 2, 1020 Vienna (Austria)

2014-04-21T23:59:59.000Z

450

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

SciTech Connect (OSTI)

Constant temperature–constant pressure (NpT) molecular-dynamics computer simulations have been carried out for the united-atom model of a non-crosslinked (1,4) cis-polyisoprene (PI) melt confined between two amorphous, fully coordinated silica surfaces. The Lennard-Jones 12-6 potential was implemented to describe the polymer–silica interactions. The thickness H of the produced PI–silica film has been varied in a wide range, 1 < H/R{sub g} < 8, where R{sub g} is the individual PI chain radius of gyration measured under the imposed confinement. After a thorough equilibration, the PI film stratified structure and polymer segmental dynamics have been studied. The chain structure in the middle of the films resembles that in a corresponding bulk, but the polymer-density profile shows a pronounced ordering of the polymer segments in the vicinity of silica surfaces; this ordering disappears toward the film middles. Tremendous slowing down of the polymer segmental dynamics has been observed in the film surface layers, with the segmental relaxation more than 150 times slower as compared to that in a PI bulk. This effect increases with decreasing the polymer-film thickness. The segmental relaxation in the PI film middles shows additional relaxation process which is absent in a PI bulk. Even though there are fast relaxation processes in the film middle, its overall relaxation is slower as compared to that in a bulk sample. The interpretation of the results in terms of polymer glassy bridges has been discussed.

Guseva, D. V., E-mail: d.v.guseva@tue.nl [Theory of Polymers and Soft Matter, Technische Universiteit Eindhoven, P.O. Box 513, 5600 MB, Eindhoven (Netherlands); Physics Department, Chair of Polymer and Crystal Physics, M. V. Lomonosov Moscow State University, 119991 Moscow (Russian Federation); Komarov, P. V. [Department of Theoretical Physics, Tver State University, Sadovyj per. 35, 170002 Tver, Russia and Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova st. 28, 119991 Moscow (Russian Federation)] [Department of Theoretical Physics, Tver State University, Sadovyj per. 35, 170002 Tver, Russia and Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova st. 28, 119991 Moscow (Russian Federation); Lyulin, Alexey V. [Theory of Polymers and Soft Matter, Technische Universiteit Eindhoven, P.O. Box 513, 5600 MB, Eindhoven (Netherlands)] [Theory of Polymers and Soft Matter, Technische Universiteit Eindhoven, P.O. Box 513, 5600 MB, Eindhoven (Netherlands)

2014-03-21T23:59:59.000Z

451

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

E-Print Network [OSTI]

Magnetic removal of Hg2+ and other heavy metal ions like Cd2+, Pb2+ etc. using silica coated magnetite particles from polluted waters is a current topic of active research to provide efficient water recycling and long term high quality water. The technique used to study the bonding characteristics of such kind of nanoparticles with the heavy metal ions is a very sensitive hyperfine specroscopy technique called the perturbed angular correlation technique (PAC).

Dash, Monika

2013-01-01T23:59:59.000Z

452

A New Concept for the Fabrication of Hydrogen Selective Silica Membranes  

SciTech Connect (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

453

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

E-Print Network [OSTI]

EFFECTS FROM ALKALI-SILICA REACTION AND DELAYED ETTRINGITE FORMATION ON REINFORCED CONCRETE COLUMN LAP SPLICES A Thesis by MARY KATHLEEN ECK Submitted to the Office of Graduate Studies of Texas A&M University in partial... by MARY KATHLEEN ECK Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved by: Chair of Committee, Joseph M. Bracci Committee Members...

Eck, Mary

2012-07-16T23:59:59.000Z

454

Structural Assessment of D-Regions Affected by Alkali-Silica Reaction/Delayed Ettringite Formation  

E-Print Network [OSTI]

STRUCTURAL ASSESSMENT OF D-REGIONS AFFECTED BY ALKALI- SILICA REACTION/DELAYED ETTRINGITE FORMATION A Dissertation by SHIH-HSIANG LIU Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of the requirements for the degree of DOCTOR OF PHILOSOPHY Approved by: Chair of Committee, Joseph M. Bracci Committee Members, John B. Mander Stefan Hurlebaus Harry A. Hogan Head of Department, John M. Niedzwecki December 2012 Major Subject: Civil...

Liu, Shih-Hsiang 1979-

2012-11-12T23:59:59.000Z

455

Thermal transport in CO2 laser irradiated fused silica: in situ measurements and analysis  

SciTech Connect (OSTI)

In situ spatial and temporal temperature measurements of pristine fused silica surfaces heated with a 10.6 {micro}m CO{sub 2} laser were obtained using an infrared radiation thermometer based on a Mercury Cadmium Telluride (MCT) camera. Laser spot sizes ranged from 250 {micro}m to 1000 {micro}m diameter with peak axial irradiance levels of 0.13 to 16 kW/cm{sup 2}. For temperatures below 2800K, the measured steady-state surface temperature is observed to rise linearly with both increasing beam size and incident laser irradiance. The effective thermal conductivity estimated over this range was approximately 2W/mK, in good agreement with classical calculations based on phonon heat capacities. Similarly, time-dependent temperature measurements up to 2000K yielded thermal diffusivity values which were close to reported values of 7 x 10{sup -7} m{sup 2}/s. Above {approx}2800K, the fused silica surface temperature asymptotically approaches 3100K as laser power is further increased, consistent with the onset of evaporative heat losses near the silica boiling point. These results show that in the laser heating regime studied here, the T{sup 3} temperature dependent thermal conductivity due to radiation transport can be neglected, but at temperatures above 2800K heat transport due to evaporation must be considered. The thermal transport in fused silica up to 2800K, over a range of conditions, can then be adequately described by a linear diffusive heat equation assuming constant thermal properties.

Yang, S T; Matthews, M J; Elhadj, S; Draggoo, V G; Bisson, S E

2009-07-07T23:59:59.000Z

456

Detection of alkali-silica reaction swelling in concrete by staining  

DOE Patents [OSTI]

A method using concentrated aqueous solutions of sodium cobaltinitrite and rhodamine B is described which can be used to identify concrete that contains gels formed by the alkali-silica reaction (ASR). These solutions present little health or environmental risk, are readily applied, and rapidly discriminate between two chemically distinct gels; K-rich, Na--K--Ca--Si gels are identified by yellow staining, and alkali-poor, Ca--Si gels are identified by pink staining.

Guthrie, Jr., George D. (Santa Fe, NM); Carey, J. William (Santa Fe, NM)

1998-01-01T23:59:59.000Z

457

Detection of alkali-silica reaction swelling in concrete by staining  

DOE Patents [OSTI]

A method using concentrated aqueous solutions of sodium cobalt nitrite and rhodamine B is described which can be used to identify concrete that contains gels formed by the alkali-silica reaction (ASR). These solutions present little health or environmental risk, are readily applied, and rapidly discriminate between two chemically distinct gels; K-rich, Na-K-Ca-Si gels are identified by yellow staining, and alkali-poor, Ca-Si gels are identified by pink staining.

Guthrie, G.D. Jr.; Carey, J.W.

1998-04-14T23:59:59.000Z

458

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

SciTech Connect (OSTI)

Uranium speciation and physical-chemical characteristics were studied in solids precipitated from synthetic acidic to circumneutral wastewaters in the presence and absence of dissolved silica and phosphate to examine thermodynamic and kinetic controls on phase formation. Composition of synthetic wastewater was based on disposal sites 216-U-8 and 216-U-12 Cribs at the Hanford site (WA, USA). In the absence of dissolved silica or phosphate, crystalline or amorphous uranyl oxide hydrates, either compreignacite or meta-schoepite, precipitated at pH 5 or 7 after 30 d of reaction, in agreement with thermodynamic calculations. In the presence of 1 mM dissolved silica representative of groundwater concentrations, amorphous phases dominated by compreignacite precipitated rapidly at pH 5 or 7 as a metastable phase and formation of poorly-crystalline boltwoodite, the thermodynamically stable uranyl silicate phase, was slow. In the presence of phosphate (3 mM), meta-ankoleite initially precipitated as the primary phase at pH 3, 5, or 7 regardless of the presence of 1 mM dissolved silica. Analysis of precipitates by U LIII-edge EXAFS indicated that “autunite-type” sheets of meta-ankoleite transformed to “phosphuranylite-type” sheets after 30 d of reaction, probably due to Ca substitution in the structure. Low solubility of uranyl phosphate phases limits dissolved U(VI) concentrations but differences in particle size, crystallinity, and precipitate composition vary with pH and base cation concentration, which will influence the thermodynamic and kinetic stability of these phases.

Kanematsu, Masakazu; Perdrial, Nicolas; Um, Wooyong; Chorover, Jon; O'Day, Peggy A.

2014-04-22T23:59:59.000Z

459

Origins of secondary silica within Yucca Mountain, Nye County, southwestern Nevada  

SciTech Connect (OSTI)

The accuracy of predictions of the hydrologic response of Yucca Mountain to future climate depends largely on how well relations between past climate and hydrology can be resolved. To advance this reconstruction, secondary minerals in and near Yucca Mountain, deposited by ground waters that originated both as surficial recharge at Yucca Mountain and from regional aquifers, are being studied to determine past ground-water sources and chemistries. Preliminary data on stable oxygen isotopes indicate that, although silica (opal, quartz, and chalcedony) and calcite and have formed in similar settings and from somewhat similar fluids, the authors have found no compelling evidence of coprecipitation or formation from identical fluids. If verified by further analyses, this precludes the use of silica-calcite mineral pairs for precise geothermometry. The preliminary data also indicate that opal and calcite occurrences in pedogenic and unsaturated-zone settings are invariably compatible with formation under modern ambient surface or subsurface temperatures. Silica and calcite stable-isotope studies are being integrated with soil geochemical modeling. This modeling will define the soil geochemical condition (climate) leading to opal or calcite deposition and to the transfer functions that may apply at the meteorologic soil unsaturated-zone interfaces. Additional study of pedogenic and unsaturated-zone silica is needed to support these models. The hypothesis that the transformation of vapor-phase tridymite to quartz requires saturated conditions is being tested through stable oxygen-isotope studies of lithophysal tridymite/quartz mixtures. Should this hypothesis be verified, mineralogic analysis by X-ray diffraction theoretically would permit reconstruction of past maximum water-table elevations.

Moscati, R.J.; Whelan, J.F.

1996-09-01T23:59:59.000Z

460

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

SciTech Connect (OSTI)

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

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.


461

Sol-gel processed silica-alumina materials for diesel engine emission reduction catalysts  

SciTech Connect (OSTI)

The incorporation of >30% silica in alumina prior to platinum impregnation improves the NOx conversion efficiency in the 200--300 C range from 45 to 57% and reduces light-off temperature. Further increase in the amount of silica to 50% is detrimental to NOx conversion efficiency. The {sup 1}H and {sup 29}Si NMR of the materials suggest that this trend is probably related to the surface acidity. The analyses of these materials by X-ray powder diffraction and electron microscopy do not reveal significant differences. Additional NOx conversion in the 350--450 C range with a maximum of 30% at 400 C can be achieved if a rhodium-impregnated 30% silica-alumina, Rh-30% SiO{sub 2}-Al{sub 2}O{sub 3}, is placed upstream of Pt-30% SiO{sub 2}-Al{sub 2}O{sub 3}. It is important to note that mixing Pt-30% SiO{sub 2}-Al{sub 2}O{sub 3} with Rh-30% SiO{sub 2}-Al{sub 2}O{sub 3} does not enhance conversion efficiency or effective temperature range.

Narula, C.K.; Rokosz, M.; Allard, L.F.; Kudla, R.J.; Chattha, M.S.

2000-04-18T23:59:59.000Z

462

Why Lead Methylammonium tri-IODIDE perovskite-based solar cells requires a mesoporous electron transporting scaffold (but not necessarily a hole conductor)  

E-Print Network [OSTI]

CH3NH3PbI3-based solar cells were characterized with electron beam-induced current (EBIC), and compared to CH3NH3PbI3-xClx ones. A spatial map of charge separation efficiency in working cells shows p-i-n structures for both thin film cells. Effective diffusion lengths, LD, (from EBIC profile) show that holes are extracted significantly more efficiently than electrons in CH3NH3PbI3, explaining why CH3NH3PbI3-based cells require mesoporous electron conductors, while CH3NH3PbI3-xClx ones, where LD values are comparable for both charge types, do not.

Edri, Eran; Henning, Alex; Mukhopadhyay, Sabyasachi; Gartsman, Konstantin; Rosenwaks, Yossi; Hodes, Gary; Cahen, David

2014-01-01T23:59:59.000Z

463

Pd-porphyrin functionalized ionic liquid-modified mesoporous SBA-15: An efficient and recyclable catalyst for solvent-free Heck reaction  

SciTech Connect (OSTI)

The Pd-porphyrin functionalized ionic liquid could be covalently anchored in the channels of mesoporous SBA-15 through ion-pair electrostatic interaction between imidazolium-cationic and Pd-porphyrin-anionic moieties. Such modified SBA-15 materials were prepared successfully via a post-synthesis (surface sol-gel polymerization) or a one-pot sol-gel procedure, which were characterized by powder X-ray diffraction, UV-visible spectroscopy, Fourier transform infrared spectroscopy, N{sub 2} sorption, elemental analysis, and transmission electron microscopy. The modified SBA-15 materials are efficient and recyclable catalysts for cross-coupling of aryl iodides or activated aryl bromides with ethyl acrylate without activity loss and Pd leaching even after 9 runs.

Zhang, Jing; Zhao, Guo-Feng [Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Chemistry Department, East China Normal University, Shanghai 200062 (China)] [Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Chemistry Department, East China Normal University, Shanghai 200062 (China); Popovic, Zora [General and Inorganic Laboratory, Chemistry Department, University of Zagreb, HR-10000 Zagreb (Croatia)] [General and Inorganic Laboratory, Chemistry Department, University of Zagreb, HR-10000 Zagreb (Croatia); Lu, Yong [Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Chemistry Department, East China Normal University, Shanghai 200062 (China)] [Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Chemistry Department, East China Normal University, Shanghai 200062 (China); Liu, Ye, E-mail: yliu@chem.ecnu.edu.cn [Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Chemistry Department, East China Normal University, Shanghai 200062 (China)] [Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Chemistry Department, East China Normal University, Shanghai 200062 (China)

2010-11-15T23:59:59.000Z

464

Journal of Catalysis 260 (2008) 342350 Contents lists available at ScienceDirect  

E-Print Network [OSTI]

strong electrostatic adsorption: II. Mesoporous silica SBA-15 L. Jiao, J.R. Regalbuto Department electrostatic adsorption Platinum Palladium Ruthenium Copper Cobalt Ammine SBA-15 Point of zero charge PZC The catalyst synthesis method of strong electrostatic adsorption (SEA) was applied to mesoporous silica SBA-15

Regalbuto, John R.

465

Preparation of macroporous carbon nanofibers with macroscopic openings in the surfaces and their applications  

E-Print Network [OSTI]

a good possibility toward industrial procedures to obtain mesoporous carbon materials [5 and polymers were interpenetrating through the pores. Silica coating on the macroporous carbon fibers enriched carbon materials [2]. Templating against mesoporous silica or self-assembled block copolymers opened

Kim, Young-Rok

466

Reduction and aggregation of silver in aqueous gelatin and silica suspensions  

SciTech Connect (OSTI)

The investigation of silver reduction and aggregation processes are of specific interest to the photographic industry, which relies heavily on photochemical equivalents of these reactions. Mechanistic insights into the formation of small silver clusters in aqueous solution have been obtained from both pulse and {gamma}-radiolytic studies. This paper examines the reduction of silver ions and the subsequent formation of silver clusters in aqueous gelatin solutions and on colloidal silica particles using the pulse radiolysis technique. The aggregation processes are compared with the parallel reactions in aqueous solutions.

Kapoor, S.; Lawless, D.; Kennepohl, P.; Meisel, D. [Argonne National Lab., IL (United States); Serpone, N. [Concordia Univ., Montreal, Quebec (Canada)

1994-06-01T23:59:59.000Z

467

Continuous process preparation of activated silica with low carbon dioxide content gas  

E-Print Network [OSTI]

Iiroduced. Activated silica is the term used to designate a negatively charged colloidal particle formed by the reactien of a dilute sodium silicate solution with a dilute solution of' an acidic material or other activant. Used as a coagulant sid to alum.... paylis (5) at Chicago found that, sodium silicate could. 'be used with paper maker's alum (aluminum sulfate) as an effective c~t aid. in treating Lake l4. chigan water. Since that time several. batch processes have been cleveloyed using various...

Burdett, Joseph Walton

1954-01-01T23:59:59.000Z

468

Femtosecond diffraction dynamics of laser-induced periodic surface structures on fused silica  

SciTech Connect (OSTI)

The formation of laser-induced periodic surface structures (LIPSS) on fused silica upon irradiation with linearly polarized fs-laser pulses (50 fs pulse duration, 800 nm center wavelength) is studied experimentally using a transillumination femtosecond time-resolved (0.1 ps-1 ns) pump-probe diffraction approach. This allows to reveal the generation dynamics of near-wavelength-sized LIPSS showing a transient diffraction at specific spatial frequencies even before a corresponding permanent surface relief was observed. The results confirm that the ultrafast energy deposition to the materials surface plays a key role and triggers subsequent physical mechanisms such as carrier scattering into self-trapped excitons.

Hoehm, S.; Rosenfeld, A. [Max-Born-Institut fuer Nichtlineare Optik und Kurzzeitspektroskopie (MBI), Max-Born-Strasse 2A, D-12489 Berlin (Germany)] [Max-Born-Institut fuer Nichtlineare Optik und Kurzzeitspektroskopie (MBI), Max-Born-Strasse 2A, D-12489 Berlin (Germany); Krueger, J.; Bonse, J. [BAM Bundesanstalt fuer Materialforschung und - pruefung, Unter den Eichen 87, D-12205 Berlin (Germany)] [BAM Bundesanstalt fuer Materialforschung und - pruefung, Unter den Eichen 87, D-12205 Berlin (Germany)

2013-02-04T23:59:59.000Z

469

Laser induced damage of fused silica polished optics due to a droplet forming organic contaminant  

SciTech Connect (OSTI)

We report on the effect of organic molecular contamination on single shot laser induced damage density at the wavelength of 351 nm, with a 3 ns pulse length. Specific contamination experiments were made with dioctylphthalate (DOP) in liquid or gaseous phase, on the surface of fused silica polished samples, bare or solgel coated. Systematic laser induced damage was observed only in the case of liquid phase contamination. Different chemical and morphological characterization methods were used to identify and understand the damage process. We demonstrate that the contaminant morphology, rather than its physicochemical nature, can be responsible for the decrease of laser induced damage threshold of optics.

Bien-Aime, Karell; Neauport, Jerome; Tovena-Pecault, Isabelle; Fargin, Evelyne; Labrugere, Christine; Belin, Colette; Couzi, Michel

2009-04-20T23:59:59.000Z

470

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

SciTech Connect (OSTI)

The electronic structure of gold nanoparticles embedded in a silica film is studied, both before and after irradiation at 355 nm by a laser. The Au 5d occupied valence states are observed by x-ray emission spectroscopy. They show that before irradiation the gold atoms are in metallic states within the nanoparticles. After irradiation with a fluence of 0.5 J/cm{sup 2}, it is found that gold valence states are close to those of a metal-poor gold silicide; thanks to a comparison of the experimental Au 5d states with the calculated ones for gold silicides using the density-functional theory. The formation of such a compound is driven by the diffusion of the gold atoms into the silica film upon the laser irradiation. At higher fluence, 1 J/cm{sup 2}, we find a higher percentage of metallic gold that could be attributed to annealing in the silica matrix.

Jonnard, P.; Bercegol, H.; Lamaignere, L.; Morreeuw, J.-P.; Rullier, J.-L.; Cottancin, E.; Pellarin, M. [Laboratoire de Chimie Physique-Matiere et Rayonnement, Universite Pierre et Marie Curie, Centre National de la Recherche Scientifique Unite Mixte de Recherche (CNRS UMR) 7614, 11 rue Pierre et Marie Curie, F-75231 Paris Cedex 05 (France); Commissariat a l'Energie Atomique/Centre d'Etudes Scientifiques et Techniques d'Aquitaine (CEA/CESTA), BP 2, F-33114, Le Barp (France); Centre Agregat Laboratoire de Spectrometrie Ionique et Moleculaire (LASIM) et Laboratoire de Physique de la Matiere Condensee et Nanostructures (LPMCN), Universite Claude Bernard Lyon I, F-69622 Villeurbanne (France)

2005-03-15T23:59:59.000Z

471

Formation of laser-induced periodic surface structures on fused silica upon two-color double-pulse irradiation  

SciTech Connect (OSTI)

The formation of laser-induced periodic surface structures (LIPSS) upon irradiation of fused silica with multiple irradiation sequences consisting of laser pulse pairs (50 fs single-pulse duration) of two different wavelengths (400 and 800 nm) is studied experimentally. Parallel polarized double-pulse sequences with a variable delay ?t between ?10 and +10 ps and between the individual fs-laser pulses were used to investigate the LIPSS periods versus ?t. These two-color experiments reveal the importance of the ultrafast energy deposition to the silica surface by the first laser pulse for LIPSS formation. The second laser pulse subsequently reinforces the previously seeded spatial LIPSS frequencies.

Höhm, S.; Herzlieb, M.; Rosenfeld, A. [Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie (MBI), Max-Born-Straße 2A, D-12489 Berlin (Germany)] [Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie (MBI), Max-Born-Straße 2A, D-12489 Berlin (Germany); Krüger, J.; Bonse, J. [BAM Bundesanstalt für Materialforschung und –prüfung, Unter den Eichen 87, D-12205 Berlin (Germany)] [BAM Bundesanstalt für Materialforschung und –prüfung, Unter den Eichen 87, D-12205 Berlin (Germany)

2013-12-16T23:59:59.000Z

472

The effect of silica gel sampling tube design on the analytical recovery of fluorine ions / by Daniel Howard Anna  

E-Print Network [OSTI]

concentrations of hydrofluoric acid. The statically generated concentrations ranged from 0. 5 to 2. 5 times the TLV. The first type of hand packed tube used foam, rather than glass wool, to hold the silica gel in place. The other type had silica gel sections... and the analyzed concentrations showed that the tubes were not statistically different at the 95% confidence level. ACKNOWLEDGMENT I would like to thank the members of my committee, Richard B. Konzen, Ph. D. , John P. Wagner, Ph. D. and Calvin B. Parnell, Ph. D...

Anna, Daniel Howard

1991-01-01T23:59:59.000Z

473

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

E-Print Network [OSTI]

We demonstrate a new class of hollow-core Bragg fibers that are composed of concentric cylindrical silica rings separated by nanoscale support bridges. We theoretically predict and experimentally observe hollow-core confinement over an octave frequency range. The bandwidth of bandgap guiding in this new class of Bragg fibers exceeds that of other hollow-core fibers reported in the literature. With only three rings of silica cladding layers, these Bragg fibers achieve propagation loss of the order of 1 dB/m.

Vienne, G; Jakobsen, C; Deyerl, H J; Jensen, J B; Sorensen, T; Hansen, T P; Huang, Y; Terrel, M; Lee, R K; Mortensen, N A; Broeng, J; Simonsen, H; Bjarklev, A; Yariv, A

2004-01-01T23:59:59.000Z

474

Dynamics of tungsten hexacarbonyl, dicobalt octacarbonyl, and their fragments adsorbed on silica surfaces  

SciTech Connect (OSTI)

Tungsten and cobalt carbonyls adsorbed on a substrate are typical starting points for the electron beam induced deposition of tungsten or cobalt based metallic nanostructures. We employ first principles molecular dynamics simulations to investigate the dynamics and vibrational spectra of W(CO){sub 6} and W(CO){sub 5} as well as Co{sub 2}(CO){sub 8} and Co(CO){sub 4} precursor molecules on fully and partially hydroxylated silica surfaces. Such surfaces resemble the initial conditions of electron beam induced growth processes. We find that both W(CO){sub 6} and Co{sub 2}(CO){sub 8} are stable at room temperature and mobile on a silica surface saturated with hydroxyl groups (OH), moving up to half an Angström per picosecond. In contrast, chemisorbed W(CO){sub 5} or Co(CO){sub 4} ions at room temperature do not change their binding site. These results contribute to gaining fundamental insight into how the molecules behave in the simulated time window of 20 ps and our determined vibrational spectra of all species provide signatures for experimentally distinguishing the form in which precursors cover a substrate.

Muthukumar, Kaliappan; Valentí, Roser; Jeschke, Harald O. [Institut für Theoretische Physik, Goethe-Universität Frankfurt, Max-von-Laue-Straße 1, 60438 Frankfurt am Main (Germany)] [Institut für Theoretische Physik, Goethe-Universität Frankfurt, Max-von-Laue-Straße 1, 60438 Frankfurt am Main (Germany)

2014-05-14T23:59:59.000Z

475

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

SciTech Connect (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

476

Molecular dynamics simulation of shock induced ejection on fused silica surface  

SciTech Connect (OSTI)

Shock response and surface ejection behaviors of fused silica are studied by using non-equilibrium molecular dynamics combining with the Tersoff potential. First, bulk structure and Hugoniot curves of fused silica are calculated and compared with experimental results. Then, the dynamical process of surface ejection behavior is simulated under different loading velocities ranging from 3.5 to 5.0?km?s, corresponding to shock wave velocities from 7.1 to 8.8?km?s. The local atomistic shear strain parameter is used to describe the local plastic deformation under conditions of shock compression or releasing. Our result shows that the shear strain is localized in the bottom area of groove under the shock compression. Surface ejection is observed when the loading velocity exceeds 4.0?km?s. Meanwhile, the temperature of the micro-jet is ?5574.7?K, which is close to experiment measurement. Several kinds of structural defects including non-bridging oxygen are found in the bulk area of the sample after ejection.

Su, Rui [College of Physical Science and Technology, Sichuan University, Chengdu 610064 (China); Xiang, Meizhen; Jiang, Shengli [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Chen, Jun, E-mail: jun-chen@iapcm.ac.cn [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Center for Applied Physics and Technology, Peking University, Beijing 100087 (China); Wei, Han [Research Center of Laser Fusion, Mianyang 621900 (China)

2014-05-21T23:59:59.000Z

477