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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

Sample Desorption/Ionization From Mesoporous Silica  

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

Sample Desorption/Ionization From Mesoporous Silica Sample Desorption/Ionization From Mesoporous Silica Sample Desorption/Ionization From Mesoporous Silica Mesoporous silica is shown to be a sample holder for laser desorption/ionization of mass spectrometry. Available for thumbnail of Feynman Center (505) 665-9090 Email Sample Desorption/Ionization From Mesoporous Silica Mesoporous silica is shown to be a sample holder for laser desorption/ionization of mass spectrometry. Supported mesoporous silica was prepared by coating an ethanolic silicate solution having a removable surfactant onto a substrate to produce a self-assembled, ordered, nanocomposite silica thin film. The surfactant was chosen to provide a desired pore size between about 1 nanometer diameter and 50 nanometers diameter. Removal of the surfactant resulted in a mesoporous silica thin

3

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

4

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

E-Print Network [OSTI]

Synthesis of highly ordered mesoporous silica materials using sodium silicate and amphiphilic block. Pinnavaia and coworkers6 have reported the synthesis of MSU-X mesoporous materials with several non- ionic and cowork- ers7 have reported the synthesis of SBA mesoporous silica materials, which have well

Kim, Ji Man

5

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

6

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

Science Journals Connector (OSTI)

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

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

2013-01-01T23:59:59.000Z

7

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

SciTech Connect (OSTI)

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

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

2012-12-15T23:59:59.000Z

8

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

SciTech Connect (OSTI)

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

Somorjai, G.A.

2009-09-14T23:59:59.000Z

9

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.

10

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

Science Journals Connector (OSTI)

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

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

2013-10-14T23:59:59.000Z

11

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

Science Journals Connector (OSTI)

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

Zahra Nasresfahani; M.Z. Kassaee

2014-01-01T23:59:59.000Z

12

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

Science Journals Connector (OSTI)

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

Haruhiko Fukumoto; Shusaku Nagano; Nobuhiro Kawatsuki; Takahiro Seki

2006-02-11T23:59:59.000Z

13

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

14

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

SciTech Connect (OSTI)

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

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

2008-09-01T23:59:59.000Z

15

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

16

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

17

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

18

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

19

Pore characteristics and hydrothermal stability of mesoporous silica: role of oleic acid  

Science Journals Connector (OSTI)

Silicate mesoporous materials were synthesized with nonionic surfactant and their surfaces were modified by oleic acid adsorption. Infrared spectrometer, nitrogen adsorption-desorption isotherm, scanning electron microscopy, and thermogravimetric analyses ...

Junhyun Choi, Yosep Han, Soyeon Park, Jayhyun Park, Hyunjung Kim

2014-01-01T23:59:59.000Z

20

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

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21

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

22

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

23

Enhanced accumulation and visible light-assisted degradation of azo dyes in poly(allylamine hydrochloride)-modified mesoporous silica spheres  

SciTech Connect (OSTI)

A new route for the economic and efficient treatment of azo dye pollutants is reported, in which surface-modified organic-inorganic hybrid mesoporous silica (MS) spheres were chosen as microreactors for the accumulation and subsequent photodegradation of pollutants in defined regions. The surface-modified silica materials were prepared by anchoring the polycationic species such as poly(allylamine hydrochloride) on MS spheres via a simple wet impregnation method. The as-synthesized spheres with well-defined porous structures exhibited 15 times of accumulating capacity for orange II and Congo red compared to that of the pure MS spheres. Diffuse reflectance UV-vis spectroscopy and confocal laser scanning microscopy demonstrated that the accumulated orange II and CR in defined MS spheres were rapidly degraded in the presence of Fenton reagent under visible radiation. Kinetics analysis in recycling degradation showed that the as-synthesized materials might be utilized as environment-friendly preconcentrators/microreactors for the remediation of dye wastewater.

Tao Xia [Key Laboratory for Nanomaterials of the Ministry of Education, Beijing University of Chemical Technology, Beijing 100029 (China)], E-mail: taoxia@yahoo.com; Liu Bing; Hou Qian; Xu Hui [Key Laboratory for Nanomaterials of the Ministry of Education, Beijing University of Chemical Technology, Beijing 100029 (China); Chen Jianfeng [Research Center of the Ministry of Education for High Gravity Engineering and Technology, Beijing University of Chemical Technology, Beijing 100029 (China)], E-mail: chenjf@mail.buct.edu.cn

2009-02-04T23:59:59.000Z

24

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

25

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

26

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

E-Print Network [OSTI]

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

Ye, Fangmao

2009-01-01T23:59:59.000Z

27

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

28

Nanomaterials, Nanotechnology  

Science Journals Connector (OSTI)

Nanotechnology is a platform technology that is finding ... This chapter explores the use of nanomaterials and nanotechnology in three areas, namely Medicine, Environment and Energy. Given the large ... nanomater...

G. Adlakha-Hutcheon; R. Khaydarov; R. Korenstein…

2009-01-01T23:59:59.000Z

29

Nanomaterials Chemistry Group - CSD  

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

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

30

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

Science Journals Connector (OSTI)

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

Sourena Sattari; Roghayeh Lotfi; Vahideh Baharmast

2008-02-01T23:59:59.000Z

31

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

Science Journals Connector (OSTI)

The measurement of isosteric heats of adsorption of silica supported amine materials in the low pressure range (0–0.1 bar) is critical for understanding the interactions between CO2 and amine sites at low coverage and hence to the development of efficient ...

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

2014-09-08T23:59:59.000Z

32

Sustainable Nanomaterials Industry Perspective  

Broader source: Energy.gov [DOE]

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

33

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

SciTech Connect (OSTI)

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

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

2008-05-09T23:59:59.000Z

34

Nanomaterials Information | The Ames Laboratory  

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

Industrial Hygiene Nanomaterials Information Nanotechnology Awareness Training through ISU EHS Approach to Nanomaterials The Safe Handling of Unbound Engineered Nanoparticles...

35

Metrology for Sustainable Nanomaterials  

Broader source: Energy.gov [DOE]

Presentation by Michael Postek (National Institute of Standards and Technology, NIST) for the Sustainable Nanomaterials Workshop on June 26, 2012

36

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 nanomaterials as well as manufacturing challenges and opportunities. Sustainable nanomaterial production from forest products enables the use of renewable and sustainable resources as substitutes for petroleum-derived materials.

37

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

38

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

39

Selective Adsorbents from Ordered Mesoporous Silica  

Science Journals Connector (OSTI)

The amino-containing OMS?NH2 adsorbent has a large adsorption capacity and a strong affinity for the Acid blue 25. ... Furthermore, these adsorbents can be regenerated by simple washing with alkaline or acid solution to recover both the adsorbents and the adsorbed dyes. ...

Ka Yee Ho; Gordon McKay; King Lun Yeung

2003-02-14T23:59:59.000Z

40

Magnetic Nanoparticle NANOMATERIALS  

E-Print Network [OSTI]

Magnetic Nanoparticle Metrology NANOMATERIALS We are developing best practice metrology for characterization of magnetic nanoparticle systems (e.g. blocking temperature, anisotropy, property distributions, T nanoparticles and provide guidelines to the FDA to properly compare systems when approving nanoparticle systems

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

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

42

silica glass  

Science Journals Connector (OSTI)

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

2009-01-01T23:59:59.000Z

43

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...

44

Brookhaven Nanoscience and Nanomaterials  

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

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

45

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

46

Mesosynthesis of ZnO?Silica Composites for Methanol Nanocatalysis  

Science Journals Connector (OSTI)

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

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

2005-08-06T23:59:59.000Z

47

Risk Assessment Approaches for Nanomaterials  

E-Print Network [OSTI]

%) with extrapolation to lower "acceptable" risk 3. Analogy or comparative toxicity to other substances with similar7/3/2013 1 Risk Assessment Approaches for Nanomaterials Eileen D. Kuempel, PhD Nanotechnology to Nanomaterials Risk Assessment 1. No observed adverse effect level (NOAEL) or lowest (LOAEL) with uncertainty

Farritor, Shane

48

Sustainable Nanomaterials from Forest Products: Umaine Perspective  

Broader source: Energy.gov [DOE]

Presentation for the Sustainable Nanomaterials Workshop by University of Maine held on June 26, 2012

49

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

50

Sustainable Nanomaterials: Emerging Governance Systems  

Science Journals Connector (OSTI)

Sustainable Nanomaterials: Emerging Governance Systems ... According to the National Nanotechnology Initiative (NNI), nanoscale materials are used in electronics, pharmaceuticals, chemicals, energy, and biomedical, among other industries. ... OECD has been energetic in this area. ...

Lynn L. Bergeson

2013-06-17T23:59:59.000Z

51

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

SciTech Connect (OSTI)

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

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

2013-02-15T23:59:59.000Z

52

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

53

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

Science Journals Connector (OSTI)

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

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

2014-01-01T23:59:59.000Z

54

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

55

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

56

Mesoporous Silica Nanoparticles and Films for Cargo Delivery  

E-Print Network [OSTI]

N. ; Schubert, U. , Aerogels—airy materials: chemistry,G. M. , Chemistry of aerogels and their applications.6, 7 particles, 8-11 aerogels, 12, 13 and xerogels. 14, 15

Guardado, Tania Maria

2014-01-01T23:59:59.000Z

57

Mesoporous Silica Nanoparticles and Films for Cargo Delivery  

E-Print Network [OSTI]

Pseudorotaxanes. Angewandte Chemie Angelos, S. ; Khashab, N.properties. Angewandte Chemie International Edition 1998,Pseudorotaxanes. Angewandte Chemie Angelos, S. ; Khashab, N.

Guardado, Tania Maria

2014-01-01T23:59:59.000Z

58

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

59

Nanomaterials for Sensing and Electrocatalysis. | EMSL  

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

nanomaterials for sensing and electrocatalysis. The emergence of nanoscience and nanotechnology has led to great advances in electrochemical science and technology, and these...

60

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

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

Synthesis of butenes through 2-butanol dehydration over mesoporous...  

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

through 2-butanol dehydration over mesoporous materials produced from ferrierite. Synthesis of butenes through 2-butanol dehydration over mesoporous materials produced from...

62

Silica Scaling Removal Process  

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

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

63

Hunting for engineered nanomaterials in the environment  

Science Journals Connector (OSTI)

Hunting for engineered nanomaterials in the environment ... Scientists will gather in Vienna to share advances related to nanomaterials in general, and the U.S. Environmental Protection Agency plans to host an invitation-only meeting about TiO2 nanoparticles in the environment. ...

Naomi Lubick

2009-07-28T23:59:59.000Z

64

Metal-based reactive nanomaterials  

Science Journals Connector (OSTI)

Recent developments in materials processing and characterization resulted in the discovery of a new type of reactive materials containing nanoscaled metal components. The well-known high oxidation energies of metallic fuels can now be released very rapidly because of the very high reactive interface areas in such metal-based reactive nanomaterials. Consequently, these materials are currently being examined for an entire range of applications in energetic formulations inappropriate for conventional, micron-sized metal fuels having relatively low reaction rates. New application areas, such as reactive structural materials, are also being explored. Research remains active in manufacturing and characterization of metal-based reactive nanomaterials including elemental metal nanopowders and various nanocomposite material systems. Because of the nanometer scale of the individual particles, or phase domains, and because of the very high enthalpy of reaction between components of the nanocomposite materials, the final phase compositions, morphology, and thermodynamic properties of the reactive nanocomposite materials may be different from those of their micron-scaled counterparts. Ignition mechanisms in such materials can be governed by heterogeneous reactions that are insignificant for materials with less developed reactive interface areas. New combustion regimes are being observed that are affected by very short ignition delays combined with very high metal combustion temperatures. Current progress in this rapidly growing research area is reviewed and some potential directions for the future research are discussed.

Edward L. Dreizin

2009-01-01T23:59:59.000Z

65

Stopping of Ions in Nanomaterials  

SciTech Connect (OSTI)

The stopping of ions in solids is due to the energy loss as a result of the resistance to ion passage of the electronic and ionic nuclei in the material. When an ion penetrates a solid, it experiences a number of collisions. Energetic charged particles interact with both electrons and atoms in materials. Kinetic energy transfers to atoms can result in displacement of atoms from their original sites; thereby forming atomic-scale defects in the structure. Energy transfers to the target electrons (either bound or free) produces electron-hole pairs that can result in charging of pre-existing defects, localized electronic excitations, rupture of covalent and ionic bonds, enhanced defect and atomic diffusion, increased free energy, changes in phase transformation dynamics, as well as formation of atomic-scale defects. Such atomic collisions and ionization processes can modify the physical and chemical behavior of nanomaterials. This box will discuss irradiation-induced defect, address nanostructure engineering and radiation effects in nanomaterials, as well as the scientific challenges of ion-solid interactions.

Zhang, Yanwen; Weber, William J.

2010-01-01T23:59:59.000Z

66

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

67

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

68

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

Science Journals Connector (OSTI)

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

Braun, A.

2005-01-19T23:59:59.000Z

69

BNL | Center for Functional Nanomaterials (CFN)  

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

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

70

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

71

Nanofabrication | Center for Functional Nanomaterials  

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

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

72

BNL | Center for Functional Nanomaterials (CFN) | Jobs  

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

Current Job Openings at the Center for Functional Nanomaterials The CFN Jobs List is currently unavailable. You may search for CFN positions in the Lab's job list. About CFN The...

73

Transformations of Nanomaterials in the Environment  

Science Journals Connector (OSTI)

‡ Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States ... Increasing use of engineered nanomaterials with novel properties relative to their bulk counterparts has generated a need to define their behaviors and impacts in the environment. ...

Gregory V. Lowry; Kelvin B. Gregory; Simon C. Apte; Jamie R. Lead

2012-05-14T23:59:59.000Z

74

Nanomaterials Safety Implementation Plan, Ames Laboratory | Department of  

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

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

75

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

76

Heterogeneous Photocatalytic Remediation of Phenol by Platinized Titania–Silica Mixed Oxides under Solar-Simulated Conditions  

Science Journals Connector (OSTI)

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

Harrison S. Kibombo; Ranjit T. Koodali

2011-11-28T23:59:59.000Z

77

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

78

Influence of heat-treatment on lithium ion anode properties of mesoporous carbons with nanosheet-like walls  

SciTech Connect (OSTI)

Highlights: ? Mesoporous carbons possess unique nanosheet-like pore walls which can be changed by heat treatment. ? Lithium ion anode properties of mesoporous carbons could be influenced by the nanosheet-like walls. ? Mesoporous carbons with nanosheet-like walls exhibit enhanced electrochemical properties LIBs. -- Abstract: Mesoporous carbons (MCs) with nanosheet-like walls have been prepared as electrodes for lithium-ion batteries by a simple one-step infiltrating method under the action of capillary flow. The influence of heat treatment temperature on the surface topography, pore/phase structure and anode performances of as-prepared materials has been investigated. The results reveal that melted liquid-crystal polycyclic aromatic hydrocarbons could be anchored on liquid/silica interfaces by molecule engineering. After carbonization, the nanosheets are formed as the pore walls of MCs and are perpendicular to the long axis of pores. The anode properties demonstrate that C-1200 displays higher reversible capacitance than those treated in higher temperature. The rate performances of C-1200 and C-1800 are similar and more excellent than that of C-2400. These improved lithium ion anode properties could be attributed to the nanosheet-like walls of MCs which can be influenced by the heat treatment temperature.

Zeng, Fanyan [College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China)] [College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China); Hou, Zhaohui, E-mail: zhqh96@163.com [College of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006 (China)] [College of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006 (China); He, Binhong [College of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006 (China)] [College of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006 (China); Ge, Chongyong; Cao, Jianguo [College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China)] [College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China); Kuang, Yafei, E-mail: yafeik@163.com [College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China)] [College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China)

2012-08-15T23:59:59.000Z

79

Synthesis and Characterization of Phosphate-coated Mesoporous...  

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

Phosphate-coated Mesoporous Titania and Cd-doping of Same via Ion-Exchange. Synthesis and Characterization of Phosphate-coated Mesoporous Titania and Cd-doping of Same via...

80

Preparation and Characterization of Novel Mesoporous Ceria?Titania  

Science Journals Connector (OSTI)

Synthesis of a novel thermally stable mesoporous ceria?titania phase using a neutral templating route is reported. The as-made inorganic-template hybrid mesostructured matrix showed a broad low-angle XRD peak characteristic of mesoporous materials. ...

Anil K. Sinha; Kenichirou Suzuki

2005-01-14T23:59:59.000Z

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


81

Sulfated Mesoporous Niobium Oxide Catalyzed 5-Hydroxymethylfurfural Formation from Sugars  

Science Journals Connector (OSTI)

Sulfated Mesoporous Niobium Oxide Catalyzed 5-Hydroxymethylfurfural Formation from Sugars ... The effectiveness of sulfated mesoporous niobium oxide (MNO-S) as a catalyst for the production of 5-hydroxymethylfurfural (5-HMF) from sugar was studied and is reported herein. ...

Ernest Lau Sze Ngee; Yongjun Gao; Xi Chen; Timothy Misso Lee; Zhigang Hu; Dan Zhao; Ning Yan

2014-08-25T23:59:59.000Z

82

Silica Scaling Removal Process  

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

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

83

DNA-incorporating nanomaterials in biotechnological applications  

SciTech Connect (OSTI)

The recently developed ability to controllably connect biological and inorganic objects on a molecular scale opens a new page in biomimetic methods with potential applications in biodetection, tissue engineering, targeted therapeutics and drug/gene delivery. Particularly in the biodetection arena, a rapid development of new platforms has largely been stimulated by a spectrum of novel nanomaterials with physical properties that offer efficient, sensitive and inexpensive molecular sensing. Recently, DNA-functionalized nano-objects have emerged as a new class of nanomaterials that can be controllably assembled in predesigned structures. Such DNA-based nanoscale structures might provide a new detection paradigm due to their regulated optical, electrical and magnetic responses, chemical heterogeneity and high local biomolecular concentration. The specific biorecognition DNA and its physical-chemical characteristics allows for an exploitation of DNA-functionalized nanomaterials for sensing of nucleic acids, while a broad tunability of DNA interactions permits extending their use for detection of proteins, small molecules and ions. We discuss the progress that was achieved in the last decade in the exploration of new detection methods based on DNA-incorporating nanomaterials as well as their applications to gene delivery. The comparison between various detection platforms, their sensitivity and selectivity, and specific applications are reviewed.

Stadler, A.; van der Lelie, D.; Chi, C.; Gang, O.

2010-02-01T23:59:59.000Z

84

Nanomaterials for Energy and Electronics Materials Science  

E-Print Network [OSTI]

crystalline silicon solar cells suffer from both high materials costs and energy-intensive production-sensitized solar cells (DSCs) based on oxide semiconductors and organic dyes have recently emerged as a promising Synthesis of ZnO Aggregates and Their Application in Dye-sensitized Solar Cells Nanomaterials for Energy

Cao, Guozhong

85

1 | P a g e MANIPULATING NANOMATERIALS  

E-Print Network [OSTI]

. As a result, such materials are restricted to applications having a static load, which is a significant material is challenging in its own right, but last summer Brochu and members of his research team (SURE) program engineered an advanced welding process capable of depositing nanomaterials on a surface

Barthelat, Francois

86

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

87

Nanoengineering Strong Silica Aerogels  

Science Journals Connector (OSTI)

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

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

2002-08-23T23:59:59.000Z

88

Sandia National Labs: PCNSC: Departments: Nanomaterials Sciences  

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

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

89

The Synthesis of Ag-Doped Mesoporous TiO2 . | EMSL  

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

The Synthesis of Ag-Doped Mesoporous TiO2 . The Synthesis of Ag-Doped Mesoporous TiO2 . Abstract: Ag-doped mesoporous titanium oxide was prepared using non-ionic surfactants and...

90

The Synthesis of Cadmium Doped Mesoporous TiO2. | EMSL  

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

The Synthesis of Cadmium Doped Mesoporous TiO2. The Synthesis of Cadmium Doped Mesoporous TiO2. Abstract: Cd doped mesoporous titanium oxide was prepared using non-ionic...

91

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

92

Nanomaterial Laboratory Safety, Boise State University | Department of  

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

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

93

Nanomaterial Laboratory Safety, Boise State University | Department of  

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

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

94

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

Science Journals Connector (OSTI)

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

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

2006-11-22T23:59:59.000Z

95

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

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

Materials Advanced Materials Find More Like This Return to Search LithiumSulfur Batteries Based on Doped Mesoporous Carbon Oak Ridge National Laboratory Contact ORNL About...

96

Design and Synthesis of Self-Assembled Monolayers on Mesoporous...  

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

Synthesis of Self-Assembled Monolayers on Mesoporous Supports (SAMMS): The Importance of Ligand Posture in Functional Design and Synthesis of Self-Assembled Monolayers on...

97

Mesoporous silicon photonic crystal microparticles: towards single-cell optical  

E-Print Network [OSTI]

in theranostics. Mesoporous silicon, where pores are in the size range of 2�50 nm, is the most relevant material

Kilian, Kristopher A.

98

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...

99

Viscosity of silica  

Science Journals Connector (OSTI)

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

Robert H. Doremus

2002-01-01T23:59:59.000Z

100

Fate, Transport, and Removal of Engineered Nanomaterials in the Aquatic Environment  

E-Print Network [OSTI]

S. , Nanomaterials and water purification: Opportunities andcosmetics, textiles, water purification and environmental

Chowdhury, Indranil

2012-01-01T23:59:59.000Z

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.


101

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

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

Aptamer-conjugated nanomaterials for specific cancer cell recognition and targeted cancer therapy  

E-Print Network [OSTI]

with multifunctional theranostic capability show promising potential in cancer therapy.4 These nanomaterials can

Tan, Weihong

105

Mesoporous Organosilica with Amidoxime Groups for CO2 Sorption  

Science Journals Connector (OSTI)

Mesoporous Organosilica with Amidoxime Groups for CO2 Sorption ... This work reports a successful use of the aforementioned strategy for the development of ordered mesoporous organosilica (OMO) with amidoxime groups for CO2 sorption. ... The resulting series of amidoxime-containing OMO was prepared and used for CO2 sorption at low (25 °C) and elevated (60, 120 °C) temperatures. ...

Chamila Gunathilake; Mietek Jaroniec

2014-07-03T23:59:59.000Z

106

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

Science Journals Connector (OSTI)

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

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

2010-03-23T23:59:59.000Z

107

NSLS Endstations | Center for Functional Nanomaterials  

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

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

108

BNL | Center for Functional Nanomaterials Data Management  

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

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

109

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

110

Pt NANOCLUSTERS ON CARBON NANOMATERIALS FOR HYDROGEN FUEL CELLS  

Science Journals Connector (OSTI)

The detailed study of carbon nanomaterials constitution with allowance for of reduction conversions Pt (II, IV) allows to realize directional looking up of methods of preparation of platinum catalysts for redo...

N.S. KUYUNKO; S.D. KUSHCH; V.E. MURADYAN…

2007-01-01T23:59:59.000Z

111

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...

112

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

113

Risk Assessment of Engineered Nanomaterials: A Survey of Industrial Approaches  

Science Journals Connector (OSTI)

Thus, voluntary industrial risk assessment initiatives can be considered vital to the environmental health and safety issues associated with engineered nanomaterials. ... However, given that NPM may cause harm (3-6) and that there are currently no regulations that take the specific properties of NPM into account, the responsibility for safe production and products is mostly left with industry. ... The prodn. of significant quantities of engineered nanomaterials will inevitably result in the introduction of these materials to the environment. ...

Aasgeir Helland; Martin Scheringer; Michael Siegrist; Hans G. Kastenholz; Arnim Wiek; Roland W. Scholz

2007-12-14T23:59:59.000Z

114

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

115

Silica Geothermometers | Open Energy Information  

Open Energy Info (EERE)

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

116

Functional Mesoporous Metal-Organic Frameworks for the Capture...  

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

Functional Mesoporous Metal-Organic Frameworks for the Capture of Heavy Metal Ions and Size-Selective Catalysis Previous Next List Qian-Rong Fang, Da-Qian Yuan, Julian Sculley,...

117

Chemistry on the inside: green chemistry in mesoporous materials  

Science Journals Connector (OSTI)

...millennium: young scientists give their visions of the future III. Chemistry and biological physics compiled by J. M. T. Thompson Chemistry on the inside: green chemistry in mesoporous materials Duncan J. Macquarrie Department of Chemistry...

2000-01-01T23:59:59.000Z

118

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

119

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

120

Capturing the Local Adsorption Structures of Carbon Dioxide in Polyamine-Impregnated Mesoporous Silica Adsorbents  

Science Journals Connector (OSTI)

Danon, A.; Stair, P. C.; Weitz, E.FTIR Study of CO2 Adsorption on Amine-Grafted SBA-15: Elucidation of Adsorbed Species J. Phys. ... Danon, Alon; Stair, Peter C.; Weitz, Eric ...

Shing-Jong Huang; Chin-Te Hung; Anmin Zheng; Jen-Shan Lin; Chun-Fei Yang; Yu-Chi Chang; Feng Deng; Shang-Bin Liu

2014-08-31T23:59:59.000Z

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.


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

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

E-Print Network [OSTI]

capillary inclusion (CI) and nanoparticle encapsulation (NE)metal nanostructures, and to collidal nanoparticle- based 2Dand 3D nanoparticle arrays. Figure 2. Preparation scheme of

Somorjai, G.A.

2010-01-01T23:59:59.000Z

123

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

E-Print Network [OSTI]

and low-power consuming implants. With the emergence of micro-electro mechanical system (MEMS) based-linked hydro- gels, sulfonated polypropylene and cuprophan,20­22 have been used to facilitate glucose diffusion and separate the electrodes. Rao et al.20,23 and Atanasov and Wilkins24 have used hydro- phobic membranes

124

New Antifouling Silica Hydrogel  

Science Journals Connector (OSTI)

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

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

2012-05-18T23:59:59.000Z

125

Mesoporous Nanostructured Nb-Doped Titanium Dioxide Microsphere Catalyst Supports for PEM Fuel Cell Electrodes  

Science Journals Connector (OSTI)

Mesoporous Nanostructured Nb-Doped Titanium Dioxide Microsphere Catalyst Supports for PEM Fuel Cell Electrodes ... The material has been investigated as cathode electrocatalyst support for polymer electrolyte membrane (PEM) fuel cells. ... doped titania; PEMFC; electrocatalyst; mesoporous materials; microspheres ...

Laure Chevallier; Alexander Bauer; Sara Cavaliere; Rob Hui; Jacques Rozière; Deborah J. Jones

2012-03-19T23:59:59.000Z

126

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

E-Print Network [OSTI]

the impact of organic oligomer size, chemistry, and surface coverage, as well as substrate pore size and structure, on membrane performance. First, we did a model study to verify the feasibility of dendrimer growth inside mesopores by using ordered mesoporous...

Yoo, Suk Joon

2009-05-15T23:59:59.000Z

127

Flame Synthesis of One-Dimensional Metal Oxide Nanomaterials  

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

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

128

Lab Breakthrough: Nanomaterials Discoveries Lead to Possible Cancer  

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

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

129

Large Scale Quantum-mechanical Calculations of Proteins, Nanomaterials and  

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

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

130

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

131

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

132

Nanotechnology in reproductive medicine: Emerging applications of nanomaterials  

Science Journals Connector (OSTI)

Abstract In the last decade, nanotechnology has been extensively introduced for biomedical applications, including bio-detection, drug delivery and diagnostic imaging, particularly in the field of cancer diagnostics and treatment. However, there is a growing trend towards the expansion of nanobiotechnological tools in a number of non-cancer applications. In this review, we discuss the emerging uses of nanotechnology in reproductive medicine and reproductive biology. For the first time, we summarise the available evidence regarding the use of nanomaterials as experimental tools for the detection and treatment of malignant and benign reproductive conditions. We also present an overview of potential applications for nanomaterials in reproductive biology, discuss the benefits and concerns associated with their use in a highly delicate system of reproductive tissues and gametes, and address the feasibility of this innovative and potentially controversial approach in the clinical setting and for investigative research into the mechanisms underlying reproductive diseases. From the Clinical Editor This unique review paper focuses on the emerging use of nanotechnology in reproductive medicine and reproductive biology, highlighting the role of nanomaterials in the detection and treatment of various reproductive conditions, keeping in mind the benefits and potential concerns associated with nanomaterial use in the delicate system of reproductive tissue and gametes.

Natalia Barkalina; Charis Charalambous; Celine Jones; Kevin Coward

2014-01-01T23:59:59.000Z

133

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

134

Preparation and Characterization of Nanomaterials for Sustainable Energy Production  

Science Journals Connector (OSTI)

Preparation and Characterization of Nanomaterials for Sustainable Energy Production ... to the various sustainable energies, but in a broader way, it collects the most recent advances of nanotechnol. ... Today, solar energy is recognized as one of the most important renewable energy sources that humanity must harness in addressing the future energy sustainability issues. ...

Chang-jun Liu; Uwe Burghaus; Flemming Besenbacher; Zhong Lin Wang

2010-10-26T23:59:59.000Z

135

SYNTHESIS OF MESOPOROUS ALUNIINOPHOSPHAI'ES AS POTENTIAL  

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

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

136

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

137

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

138

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

139

Nanomaterials and nanoparticles: Sources and toxicity  

Science Journals Connector (OSTI)

This review is presented as a common foundation for scientists interested in nanoparticles their origin activity and biological toxicity. It is written with the goal of rationalizing and informing public health concerns related to this sometimes-strange new science of “nano ” while raising awareness of nanomaterials’ toxicity among scientists and manufacturers handling them. We show that humans have always been exposed to tiny particles via dust storms volcanic ash and other natural processes and that our bodily systems are well adapted to protect us from these potentially harmful intruders. The reticuloendothelial system in particular actively neutralizes and eliminates foreign matter in the body including viruses and nonbiological particles. Particles originating from human activities have existed for millennia e.g. smoke from combustion and lint from garments but the recent development of industry and combustion-based engine transportation has profoundly increased anthropogenic particulate pollution. Significantly technological advancement has also changed the character of particulate pollution increasing the proportion of nanometer-sized particles-“nanoparticles”-and expanding the variety of chemical compositions. Recent epidemiological studies have shown a strong correlation between particulate air pollution levels respiratory and cardiovascular diseases various cancers and mortality. Adverse effects of nanoparticles on human health depend on individual factors such as genetics and existing disease as well as exposure and nanoparticle chemistry size shape agglomeration state and electromagnetic properties. Animal and human studies show that inhaled nanoparticles are less efficiently removed than larger particles by the macrophage clearance mechanisms in the lungs causing lung damage and that nanoparticles can translocate through the circulatory lymphatic and nervous systems to many tissues and organs including the brain. The key to understanding the toxicity of nanoparticles is that their minute size smaller than cells and cellular organelles allows them to penetrate these basic biological structures disrupting their normal function. Examples of toxic effects include tissue inflammation and altered cellular redox balance toward oxidation causing abnormal function or cell death. The manipulation of matter at the scale of atoms “nanotechnology ” is creating many new materials with characteristics not always easily predicted from current knowledge. Within the nearly limitless diversity of these materials some happen to be toxic to biological systems others are relatively benign while others confer health benefits. Some of these materials have desirable characteristics for industrial applications as nanostructured materials often exhibit beneficial properties from UV absorbance in sunscreen to oil-less lubrication of motors. A rational science-based approach is needed to minimize harm caused by these materials while supporting continued study and appropriate industrial development. As current knowledge of the toxicology of “bulk” materials may not suffice in reliably predicting toxic forms of nanoparticles ongoing and expanded study of “nanotoxicity” will be necessary. For nanotechnologies with clearly associated health risks intelligent design of materials and devices is needed to derive the benefits of these new technologies while limiting adverse health impacts. Human exposure to toxic nanoparticles can be reduced through identifying creation-exposure pathways of toxins a study that may someday soon unravel the mysteries of diseases such as Parkinson’s and Alzheimer’s. Reduction in fossil fuel combustion would have a large impact on global human exposure to nanoparticles as would limiting deforestation and desertification. While nanotoxicity is a relatively new concept to science this review reveals the result of life’s long history of evolution in the presence of nanoparticles and how the human body in particular has adapted to defend itself against nanoparticulate intruders.

Cristina Buzea; Ivan I. Pacheco; Kevin Robbie

2007-01-01T23:59:59.000Z

140

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

Science Journals Connector (OSTI)

Abstract High activity of glucose oxidase (GOD) enzyme (immobilized in porous silica particles) is desirable for a better glucose biosensor. In this work, effect of pore diameter of two porous hosts on enzyme immobilization, activity and glucose sensing was compared. The hosts were amine functionalized: (i) microporous silica (NH2-MS) and (ii) mesoporous silica (NH2-SBA-15). Based on whether the dimension of GOD is either larger or smaller than the pore diameter, GOD was immobilized on either external or internal surface of NH2-MS and NH2-SBA-15, with loadings of 512.5 and 634 mg/g, respectively. However, GOD in NH2-SBA-15 gave a higher normalized absolute activity (NAA), which led to an amperometric sensor with a larger linear range of 0.4–13.0 mM glucose. In comparison, GOD in NH2-MS had a lower NAA and a smaller linear range of 0.4–3.1 mM. In fact, the present GOD-NH2-SBA-15 electrode based sensor was better than other MS and SBA-15 based electrodes reported in literature. Thus, achieving only a high GOD loading (as in NH2-MS) does not necessarily give a good sensor performance. Instead, a host with a relatively larger pore than enzyme, together with optimized electrode composition ensures the sensor to be functional in both hyper- and hypoglycemic range.

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

2014-01-01T23:59:59.000Z

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

Hydrophobic silica aerogel reinforced with carbon nanotube for oils removal  

Science Journals Connector (OSTI)

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

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

2014-08-01T23:59:59.000Z

142

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

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

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

143

iCFN | Center for Functional Nanomaterials Newsletter | Issue Archives  

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

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

144

2007 Synthesis and Self-assembly of Nanomaterials Workshop Summary  

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

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

145

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

146

Novel Magnetic Nanomaterials Inspired by Magnetotactic Baterial: Topical Review  

SciTech Connect (OSTI)

Magnetotactic bacteria, known to produce magnetic nanocrystals with uniform shapes and sizes at physiological conditions, serve as an inspiration and source of a number of biological macromolecules used for the biomimetic synthesis of a variety of magnetic nanomaterials. This review discusses the current state of understanding of magnetosome biomineralization in magnetotactic bacteria, as well as the ways in which iron biomineralization processes can be utilized for tailored in vivo formation of complex magnetic nanomaterials, not occurring in magnetotactic bacteria naturally. The review assesses the current efforts on in vitro synthesis of a variety of magnetic nanoparticles using bioinspired approaches by utilizing mineralization proteins from magnetotactic bacteria, and surveys biomimetic strategies for the rational synthesis of various magnetic nanomaterials under ambient conditions. Finally, this review presents magnetic characterization of nanoparticles, highlighting differences in magnetic behavior between magnetic nanoparticles produced using bioinspired in vivo and in vitro strategies, compared to those produced using conventional methods. This in turn impacts their utility in a wide range of applications for magnetic nanoparticles, which are examined in detail, where bioinspired synthesis methods have potentially provided added advantages.

Prozorov, Tanya [Ames Laboratory; Bazylinki, Dennis A. [University of Nevada, Las Vegas; Mallapragada, Surya K. [Ames Laboratory; Prozorov, Ruslan [Ames Laboratory

2013-05-14T23:59:59.000Z

147

Analyzing Nanomaterial Bioconjugates: A Review of Current and Emerging Purification and Characterization Techniques  

Science Journals Connector (OSTI)

Analyzing Nanomaterial Bioconjugates: A Review of Current and Emerging Purification and Characterization Techniques ... This article is part of the Fundamental and Applied Reviews in Analytical Chemistry special issue. ...

Kim E. Sapsford; Katherine M. Tyner; Benita J. Dair; Jeffrey R. Deschamps; Igor L. Medintz

2011-05-05T23:59:59.000Z

148

One-pot synthesis of highly mesoporous antimony-doped tin oxide...  

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

One-pot synthesis of highly mesoporous antimony-doped tin oxide from interpenetrating inorganicorganic networks Authors: Volosin, A.M., Sharma, S., Traverse, C., Newman, N., and...

149

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

150

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

E-Print Network [OSTI]

The objective of this study is to synthesize nanomaterials by mixing molten salt (alkali nitrate salt eutectics) with inorganic nanoparticles. The thermo-physical properties of the synthesized nanomaterials were characterized experimentally...

Jung, Seunghwan

2012-07-16T23:59:59.000Z

151

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

152

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

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

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

153

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

154

Facile synthesis of mesoporous lithium titanate spheres for high rate lithium-ion batteries  

Science Journals Connector (OSTI)

Lithium titanate is synthesized from titanium isopropoxide and lithium acetate solution under hydrothermal environment and calcinations. Introducing acidized carbon black during synthesis can produce mesoporous Li4Ti5O12. The crystalline structure and morphological observation of the as-synthesized mesoporous Li4Ti5O12 are characterized by X-ray diffraction (XRD) and scanning electron microscopy, respectively. The mesoporous structure can be directly observed through BEI images of the cross-section sample. Besides, N2 adsorption/desorption isotherm also displays a hysteresis loop, implying the beneficial evidence of mesoporous structure. The pore size distribution of mesoporous lithium titanate evaluated by BJH model is narrow, and the average size of voids is around 4 nm. It is demonstrated that the electrochemical performance is significantly improved by the mesoporous structure. The mesoporous lithium titanate exhibits a stable capacity of 140 mAhg?1 at 0.5 C. Besides, the reversible capacity at 30 C remains over half of that at 0.5 C. The superior C-rate performance is associated with the mesoporous structure, facilitating lithium transportation ability during cycling.

Yu-Sheng Lin; Jenq-Gong Duh

2011-01-01T23:59:59.000Z

155

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

156

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

157

Energetic nano-materials: Opportunities for enhanced performances  

Science Journals Connector (OSTI)

This paper deals with the contribution of nano-materials to the contemporary pyrotechnics science. The breakthroughs in this domain are illustrated by several examples of energetic nano-materials recently studied in our laboratory. The solidification of energetic phases in a porous matrix (Cr2O3) was used to prepare and to stabilize at nano-scale explosive particles. The thermo-chemical behaviour of RDX nano-particles strongly differs from the one of micron-sized RDX. For instance, the temperature at which the decomposition occurs is significantly lowered and the melting point is removed. The effect of the decomposition of RDX nano-particles on the matrix in which they are trapped was observed for the first time by the atomic force microscopy. The Cr2O3/RDX nano-composite materials were mixed with aluminium nano-particles in order to formulate gas-generating nano-thermites (GGNT). The combustion of GGNT involves a synergy mechanism in which the decomposition of RDX nano-particles fragments the Cr2O3 matrix and primes the thermite reaction. “Classical” nano-thermites were obtained by mixing nano-particles (diameter <100 nm) of metallic oxides (WO3) with a reducing metal (Al). These materials were used to demonstrate that nano-particles (i) significantly lower the ignition delay time and (ii) remarkably increase the combustion rate. Finally, pure RDX nano-particles are prepared by a continuous process of crystallization.

Denis Spitzer; Marc Comet; Christian Baras; Vincent Pichot; Nelly Piazzon

2010-01-01T23:59:59.000Z

158

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

159

Graphene anchored with mesoporous NiO nanoplates as anode material for lithium-ion batteries  

Science Journals Connector (OSTI)

Graphene is an excellent substrate to load nanomaterials ... stability. In this study, thermal exfoliated functionalized graphene sheets with good conductivity and high BET ... synthesis approach. Electrochemical...

Danfeng Qiu; Zijing Xu; Mingbo Zheng; Bin Zhao…

2012-05-01T23:59:59.000Z

160

Electroactive Silica Nanoparticles for Biological Labeling. ...  

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

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

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

INTERACTION OF MARINE SEDIMENTS WITH DISSOLVED SILICA  

Science Journals Connector (OSTI)

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

2000-02-10T23:59:59.000Z

162

Silica Supported Ceria Nanoparticles: A Hybrid Nanostructure...  

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

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

163

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

Science Journals Connector (OSTI)

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

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

2012-01-01T23:59:59.000Z

164

Fluorescent Silica Nanoparticles with Efficient Urinary Excretion for Nanomedicine  

Science Journals Connector (OSTI)

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

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

2008-12-19T23:59:59.000Z

165

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...

166

A Targeted Cancer Treatment using Nanomaterials | Advanced Photon Source  

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

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

167

Nanomaterials for LightManagement in Electro-Optical Devices  

SciTech Connect (OSTI)

In the past decade, nanostructured materials and nanoparticles have emerged as the necessary ingredients for electrooptical applications and enhancement of device performance, in particular by making use of the light management aspects of the nanomaterials. The application areas that are being transformed profoundly include smart coating devices (e.g., electrochromic, photochromic, and thermochromic devices), solar energy, and sensing. Despite the large volume of work in the past on smart coating devices, and in particular on electrochromic devices and thermochromic fenestrations, for optical transmission or reflection control, applications remain limited because of slow response time and nonuniformity in the case of large surfaces. Recent works in the field indicate that nanostructured electrochromic coatings would be an integral part of the solution to the above problem. One aspect that can thus be focused on would be the fabrication and characterization of the nanostructured smart coating materials and their compatibility with other layers in the overall smart coating device. In the area of solar photovoltaics, nanomaterials have been used in designing light-trapping schemes for inorganic as well as organic solar cells. One particular category of solar cells that has attracted much interest is the plasmonic solar cells in which metallic nanoparticles are incorporated, helping in enhancing their energy conversion efficiency. Nanostructured solar cells would eventually develop into a 'game changing' technology for making solar cells that are affordable and highly efficient, providing a sizeable alternative energy source for our ever-increasing energy needs. Sensors based on the optical properties of constituting nanostructures and nanoparticles also form a most interesting class of bio- and electrochemical sensing devices. The possibility of synthetizing nanoparticles and structures of specifically desired sizes and shapes has indeed opened a whole new range of sensing applications. In parallel to the experimental development of nanomaterials for light management in devices, theoretical modeling and analysis have also accomplished much progress, and different methods for simulating the optical properties of nanoparticles and structures have been proposed. This special issue of the Journal of Nanomaterials is thus dedicated to articles dealing with nanostructured materials that can be used for light management purpose in different applications. Silicon-rich oxide (SRO) is a dielectric material that contains Si nanoparticles and exhibits interesting physical characteristics for applications in optoelectronic devices. The work by Aceves-Mijares et al. examine, in detail the electro-, cathode- and photoluminescence properties of SRO and discuss the origin of light emission in this type of materials. SRO films, of high and medium silicon excess density, obtained by low-pressure chemical vapor deposition and annealed at 1,100 C have been studied. Results obtained by the authors have led to conclude that SRO emission properties are due to oxidation state nanoagglomerates rather than to nanocrystals, and the emission mechanism is similar to that in the donor-acceptor decay in semiconductors with a specific wide emission spectrum. Two papers are devoted to nanostructured electrochromic thin films, a category of materials most suitable for controlling light transmission or absorption in electrooptical devices, including smart window coatings. Dinh et al. have shown that by mixing nanostructured Ti and W oxides films, one can obtain devices with considerable enhancement of electrochromic efficiency and electrochemical stability as compared to the conventional nonnanostructured films. As large-area mixed Ti and W oxides can be prepared by the simple doctor blade technique followed by an electrochemical process, this type of nanostructured electrochromic films can be considered a good candidate for smart window applications. Djaoued et al. have presented their studies on the synthesis, characterization, and electrochromic applicatio

Truong, Vo-Van [Concordia University, Montréal, Québec, H4B 1R6, Canada; Singh, Jai [Charles Darwin University, Darwin, Australia; Tanemura, Sakae [Japan Fine Ceramics Center, Nagoya, Japan; Hu, Michael Z. [ORNL

2012-01-01T23:59:59.000Z

168

Structure of Random Porous Materials: Silica Aerogel  

Science Journals Connector (OSTI)

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

Dale W. Schaefer and Keith D. Keefer

1986-05-19T23:59:59.000Z

169

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

170

Engineered nanomaterials: knowledge gaps in fate, exposure, toxicity, and future directions  

Science Journals Connector (OSTI)

The aim of this study is to identify current knowledge gaps in fate, exposure, and toxicity of engineered nanomaterials (ENMs), highlight research gaps, and suggest future research directions. Humans and other living organisms are exposed to ENMs during ...

Arun Kumar, Prashant Kumar, Ananthitha Anandan, Teresa F. Fernandes, Godwin A. Ayoko, George Biskos

2014-01-01T23:59:59.000Z

171

Shape-Controlled Synthesis of Hybrid Nanomaterials via Three-Dimensional Hydrodynamic Focusing  

Science Journals Connector (OSTI)

Shape-Controlled Synthesis of Hybrid Nanomaterials via Three-Dimensional Hydrodynamic Focusing ... Components of this work were conducted at the Penn State node of the NSF-funded National Nanotechnology Infrastructure Network. ...

Mengqian Lu; Shikuan Yang; Yi-Ping Ho; Christopher L. Grigsby; Kam W. Leong; Tony Jun Huang

2014-09-30T23:59:59.000Z

172

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

E-Print Network [OSTI]

to 500 ?C, and soaking in water at room temperature under various atmospheres, and weathering in the powder form at room temperature under various atmospheres. The redox capability of the carbon nanomaterials was quantified in terms of the reductive...

Lee, Chunghoon

2012-10-19T23:59:59.000Z

173

Targeted Intracellular Delivery of Antituberculosis Drugs to Mycobacterium tuberculosis-Infected Macrophages via Functionalized Mesoporous Silica Nanoparticles  

Science Journals Connector (OSTI)

...a 5% CO2-95% air atmosphere. Prior to their use...a 5% CO2-95% air atmosphere. Immunofluorescence...a 5% CO2-95% air atmosphere. Macrophages on coverslips...temperature to stain plasma membranes, washed with...areas at a speed of 400 MHz and a resolution of...

Daniel L. Clemens; Bai-Yu Lee; Min Xue; Courtney R. Thomas; Huan Meng; Daniel Ferris; Andre E. Nel; Jeffrey I. Zink; Marcus A. Horwitz

2012-02-21T23:59:59.000Z

174

Targeted Intracellular Delivery of Antituberculosis Drugs to Mycobacterium tuberculosis-Infected Macrophages via Functionalized Mesoporous Silica Nanoparticles  

Science Journals Connector (OSTI)

...a 5% CO2-95% air atmosphere. Immunofluorescence...a 5% CO2-95% air atmosphere. Macrophages on coverslips...temperature to stain plasma membranes, washed with...areas at a speed of 400 MHz and a resolution of 1...Published ahead of print 21 February 2012 ACKNOWLEDGMENTS...

Daniel L. Clemens; Bai-Yu Lee; Min Xue; Courtney R. Thomas; Huan Meng; Daniel Ferris; Andre E. Nel; Jeffrey I. Zink; Marcus A. Horwitz

2012-02-21T23:59:59.000Z

175

Vanadium Mesoporous Silica Catalyst Prepared by Direct Synthesis as High Performing Catalyst in Oxidative Dehydrogenation of n-Butane  

Science Journals Connector (OSTI)

The catalytic oxidative dehydrogenation (ODH) of light alkanes has great potential to be used for production of alkenes instead classically used dehydrogenation. We report successful direct synthesis of vanadi...

Michal Setni?ka; Pavel ?i?manec; Roman Bulánek; Arnošt Zukal…

2014-01-01T23:59:59.000Z

176

Evaluation of Dysprosia Aerogels as Drug Delivery Systems: A Comparative Study with Random and Ordered Mesoporous Silicas  

Science Journals Connector (OSTI)

The high drug uptake and slow release from dysprosia aerogels, in combination with their low toxicity, strong paramagnetism, and the possibility for neutron activation render those materials attractive multifunctional vehicles for site-specific drug delivery. ... X-rdm-DyOx aerogel samples (1 mg) were incubated with fresh human whole blood (30 ?L, Oklahoma Blood Institute, Oklahoma City, OK) for 24 h at room temperature. ...

Abhishek Bang; Anand G. Sadekar; Clayton Buback; Brice Curtin; Selin Acar; Damir Kolasinac; Wei Yin; David A. Rubenstein; Hongbing Lu; Nicholas Leventis; Chariklia Sotiriou-Leventis

2014-03-25T23:59:59.000Z

177

Adsorptive desulfurization of low sulfur diesel fuel using palladium containing mesoporous silica synthesized via a novel in-situ approach  

Science Journals Connector (OSTI)

Abstract In this work, a novel in-situ synthesis route was applied for preparation of an adsorbent, i.e. palladium containing MCM-41. At first, a hydrophobic palladium precursor was added to the ethanolic micellar solution followed by vacuum distillation of ethanol which decreases the hydrophobic characteristic of the solution. Distillation caused diffusion of hydrophobic palladium precursor into the hydrophobic core of the micelles. Then, tetraethyl orthosilicate was added to the above solution and the silicate spices arranged around the palladium containing micelles. The XRD, N2 physisorption and TEM studies revealed that 4 wt.% palladium loading was achieved without considerable loss of pore ordering. H2-TPR showed that the palladium nanoparticles were accessible for hydrogen molecules. Adsorptive desulfurization of low sulfur diesel fuel was then investigated using synthesized samples. The effect of three valuable parameters, i.e., temperature (25, 75, 150 and 200 °C), concentration of palladium (2, 4 and 5 wt.%) and feed flow rate (0.3 and 1 mL/min) were tested using a fixed-bed flowing device. The highest sulfur break through adsorption capacity and total sulfur adsorption capacity obtained at 200 °C, 0.3 mL/min of feed flow rate and 4 wt.% of palladium concentration were 1.67 and 2.35 mg sulfur/g adsorbent, respectively.

Mohammad Teymouri; Abdolraouf Samadi-Maybodi; Amir Vahid; Aliakbar Miranbeigi

2013-01-01T23:59:59.000Z

178

Simultaneous Adsorption of H2S and CO2 on Triamine-Grafted Pore-Expanded Mesoporous MCM-41 Silica  

Science Journals Connector (OSTI)

It is also being upgraded to biomethane and fed into the natural gas grid or in dedicated pipelines. ... The production of high-quality biomethane from biogas requires the separation of CO2, H2S, and water vapor to meet strict specifications. ...

Youssef Belmabkhout; Nicolas Heymans; Guy De Weireld; Abdelhamid Sayari

2011-02-04T23:59:59.000Z

179

Synthesis and textural evolution of alumina particles with mesoporous structures  

SciTech Connect (OSTI)

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

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

2010-06-15T23:59:59.000Z

180

Silica Nanoparticles and Frameworks from Rice Husk Biomass  

Science Journals Connector (OSTI)

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

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

2011-12-29T23:59:59.000Z

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

Mesoporous Carbons for More Kick > EMC2 News > The Energy Materials...  

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

image shows the wavy pattern of a gyroidal mesoporous carbon. Jimmy O'Dea In an electric car you want a battery that has enough juice to get you across town and enough kick to...

182

Ordered mesoporous carbon/SnO2 composites as the electrode material for supercapacitors  

Science Journals Connector (OSTI)

A series of composites as electrode materials for supercapacitors were prepared via incipient wetness impregnation method utilizing ordered mesoporous carbon (OMC) and tin (IV) oxide (SnO2) with different ratio. ...

Ping Liu ??; Bohejin Tang; Jiachang Zhao…

2011-06-01T23:59:59.000Z

183

Structure and functionalization of mesoporous bioceramics for bone tissue regeneration and local drug delivery  

Science Journals Connector (OSTI)

...promote the bone regeneration process. mesoporous bioceramics...accelerating the healing process. Thus, the design, development and commercialization of bioactive and biodegradable...elements play key roles in the processes that promote bone formation...

2012-01-01T23:59:59.000Z

184

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

Science Journals Connector (OSTI)

Abstract Usage of aerogels as an adsorbent has become more widespread because of its specifications such as high porosity and specific surface. Nanometer silica aerogel and silica aerogel-activated carbon composites were synthesized using a water glass precursor by ambient pressure drying method. Then, the adsorption capacity of synthesized adsorbents was studied in terms of benzene and ethyl benzene adsorption by chromatography method for continuous and batch testing. Results showed that silica aerogel and silica aerogel-activated carbon composites had high tendency for benzene and ethyl benzene adsorption. Silica aerogel showed maximum adsorption capacity of 2.3 g g?1 and 0.7 g g?1 in static adsorption of benzene and ethyl benzene respectively. Also, in dynamic adsorption of benzene and ethyl benzene, silica aerogel had maximum equilibrium adsorption capacity of 0.954 g g?1 and 0.219 g g?1 respectively. Minimum equilibrium adsorption capacity in benzene and ethyl benzene static adsorption was related to activated carbon with 0.7 g g?1 and silica aerogel–2 wt% activated carbon with 0.25 g g?1 respectively. After adsorption process, silica aerogel and silica aerogel–0.5 wt% activated carbon composite were regenerated by solvent extraction–thermal treatment method and, after at least 15 adsorption/desorption cycles, their adsorption capacity became fixed.

Akbar Mohammadi; Jafarsadegh Moghaddas

2014-01-01T23:59:59.000Z

185

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

186

Vibrational amplitudes in vitreous silica  

Science Journals Connector (OSTI)

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

Alfredo Pasquarello

2000-02-01T23:59:59.000Z

187

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

188

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

189

Elastic instabilities in dry, mesoporous minerals and their relevance to geological applications  

Science Journals Connector (OSTI)

...exponent m was predicted for foams and aerogels. Open cell foams show exponents m...evaluation of elastic properties of silica aerogels. Materials Science and Engineering A...scaling law relationships for silica aerogels and their organic counterparts. Materials...

E. K. H. Salje; J. Koppensteiner; W. Schranz; E. Fritsch

190

Daniela Rodica Radu  

Office of Scientific and Technical Information (OSTI)

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

191

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

SciTech Connect (OSTI)

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

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

2013-04-09T23:59:59.000Z

192

Fluoroalkylsilane versus alkylsilane as hydrophobic agents for silica and silicates  

Science Journals Connector (OSTI)

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

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

2013-01-01T23:59:59.000Z

193

Electrostatically Tuned Interactions in Silica Microsphere-Polystyrene Nanoparticle Mixtures  

E-Print Network [OSTI]

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

Lewis, Jennifer

194

Nano-Macro Correlation of Nano-Silica Concrete  

Science Journals Connector (OSTI)

Concrete mixes using progressively finer size nano-silica particles (7–150nm) were prepared to study the effect of nano-size pozzolans (nano-silica). Conventional compression tests demonstrated progressively high...

Joan Schoepfer; Arup Maji

2013-01-01T23:59:59.000Z

195

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

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

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

196

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

197

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

198

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

Science Journals Connector (OSTI)

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

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

2008-05-01T23:59:59.000Z

199

Silica Sol as a Nanoglue: Flexible Synthesis of Composite Aerogels  

Science Journals Connector (OSTI)

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

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

1999-04-23T23:59:59.000Z

200

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

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

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

202

Many advances in the understanding and design of nanomaterials have been enabled by spectroscopic  

E-Print Network [OSTI]

SEMTE abstract Many advances in the understanding and design of nanomaterials have been enabled of electrochemical cells, batteries, dye-sensitized solar cells, and water-splitting photosystems. In this talk, I and Storage Dr. Ismaila Dabo Department of Scientific Computing �cole des Ponts, Université Paris ­ Est

Reisslein, Martin

203

Graphene based nanomaterials for VLSI interconnect and energy-storage applications  

Science Journals Connector (OSTI)

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

Kaustav Banerjee

2009-07-01T23:59:59.000Z

204

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

205

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

206

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

207

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

208

Origin of Libyan Desert Silica-Glass  

Science Journals Connector (OSTI)

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

ALVIN J. COHEN

1959-05-30T23:59:59.000Z

209

Molecular sieving silica membrane fabrication process  

DOE Patents [OSTI]

A process for producing a molecular sieve silica membrane comprising depositing a hybrid organic-inorganic polymer comprising at least one organic constituent and at least one inorganic constituent on a porous substrate material and removing at least a portion of the at least one organic constituent of the hybrid organic-inorganic polymer, forming a porous film.

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

1998-01-01T23:59:59.000Z

210

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

211

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

212

Iron acetylacetonate complex anchored on silica xerogel polymer  

Science Journals Connector (OSTI)

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

Marcia C. Brasil; Edilson V. Benvenutti; José R. Gregório; Annelise E. Gerbase

2005-01-01T23:59:59.000Z

213

Mesoporous MnO2/Carbon Aerogel Composites as Promising Electrode Materials for High-Performance Supercapacitors  

Science Journals Connector (OSTI)

Mesoporous MnO2/Carbon Aerogel Composites as Promising Electrode Materials for High-Performance Supercapacitors ... In this Letter, we explored a novel route to prepare mesoporous MnO2/carbon aerogel composites by electrochemical deposition assisted by gas bubbles. ... The results of nitrogen adsorption?desorption experiments and electrochemical measurements showed that these obtained mesoporous MnO2/carbon aerogel composites had a large specific surface area (120 m2/g), uniform pore-size distribution (around 5 nm), high specific capacitance (515.5 F/g), and good stability over 1000 cycles, which give these composites potential application as high-performance supercapacitor electrode materials. ...

Gao-Ren Li; Zhan-Ping Feng; Yan-Nan Ou; Dingcai Wu; Ruowen Fu; Ye-Xiang Tong

2010-01-12T23:59:59.000Z

214

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

Science Journals Connector (OSTI)

Using molecular simulation, we investigate the effect of nitrogen doping on adsorption capacity and selectivity of CO2 versus N2 in model mesoporous carbon. We show that nitrogen doping greatly enhances CO2 adsorption capacity; with a 7 wt % dopant ...

Ravichandar Babarao; Sheng Dai; De-en Jiang

2012-02-29T23:59:59.000Z

215

Carbon aerogel with 3-D continuous skeleton and mesopore structure for lithium-ion batteries application  

Science Journals Connector (OSTI)

Abstract Carbon aerogel (CA) with 3-D continuous skeleton and mesopore structure was prepared via a microemulsion-templated sol–gel polymerization method and then used as the anode materials of lithium-ion batteries. It was found that the reversible specific capacity of the as-prepared \\{CAs\\} could stay at about 470 mA h g?1 for 80 cycles, much higher than the theoretical capacity of commercial graphite (372 mAh g?1). In addition, CA also showed a better rate capacity compared to commercial graphite. The good electrochemical properties could be ascribed to the following three factors: (1) the large BET surface area of 620 m2 g?1, which can provide more lithium ion insertion sites, (2) 3-D continuous skeleton of CAs, which favors the transport of the electrons, (3) 3-D continuous mesopore structure with narrow mesopore size distribution and high mesopore ratio of 87.3%, which facilitates the diffusion and transport of the electrolyte and lithium ions.

Xiaoqing Yang; Hong Huang; Guoqing Zhang; Xinxi Li; Dingcai Wu; Ruowen Fu

2015-01-01T23:59:59.000Z

216

Mesoporous composite cathode materials prepared from inverse micelle structures for high  

E-Print Network [OSTI]

active materials in LIBs. Manganese oxide-based compounds are particularly attrac- tive as cathodes owingMesoporous composite cathode materials prepared from inverse micelle structures for highCoO2) is the most common active material.1 However, since natural deposits of cobalt are scarce

Cao, Guozhong

217

Short communication Mesoporous nitrogen-rich carbon materials as cathode catalysts in  

E-Print Network [OSTI]

Short communication Mesoporous nitrogen-rich carbon materials as cathode catalysts in microbial activity for ORR [7]. The procedures to make these materials have required several synthesis steps, long catalytic activity is thought to be due to production of nitrogen-containing carbon materials

218

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

219

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

SciTech Connect (OSTI)

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

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

2012-01-01T23:59:59.000Z

220

Cryogenic properties of optomechanical silica microcavities  

E-Print Network [OSTI]

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

Olivier Arcizet; Rémi Rivière; Albert Schliesser; Tobias J. Kippenberg

2009-01-09T23:59:59.000Z

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.


221

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

222

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

223

Catalytic Deoxygenation of Tall Oil Fatty Acids Over a Palladium-Mesoporous Carbon Catalyst: A New Source of Biofuels  

Science Journals Connector (OSTI)

Catalytic deoxygenation of tall oil fatty acids (TOFA) was demonstrated over palladium catalysts supported on mesoporous carbon at 300 °C using dodecane as a solvent. Maximally 95% selectivity to linear C17 hy...

Bartosz Rozmys?owicz; Päivi Mäki-Arvela; Siswati Lestari…

2010-09-01T23:59:59.000Z

224

Graphene-encapsulated mesoporous SnO2 composites as high performance anodes for lithium-ion batteries  

Science Journals Connector (OSTI)

Mesoporous metal oxides such as SnO2...exhibit a superior electrochemical performance as anode materials for lithium-ion batteries due to their large surface areas and ... collapse during the charge–discharge pro...

Shuhua Jiang; Wenbo Yue; Ziqi Gao; Yu Ren; Hui Ma…

2013-05-01T23:59:59.000Z

225

CH4 reforming with CO2 for syngas production over nickel catalysts supported on mesoporous nanostructured ?-Al2O3  

Science Journals Connector (OSTI)

Nanostructured ?-Al2O3 with high surface area and mesoporous structure was synthesized by sol-gel method and employed as catalyst support for nickel catalysts in methane reforming with carbon dioxide. The prepare...

Nasrollah Majidian; Narges Habibi; Mehran Rezaei

2014-07-01T23:59:59.000Z

226

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

Office of Science (SC) Website

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

227

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

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

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

228

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

229

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

230

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

SciTech Connect (OSTI)

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

Palo, Daniel R.

2011-04-26T23:59:59.000Z

231

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

232

Acid-Functionalized SBA-15-Type Periodic Mesoporous Organosilicas and Their Use in the Continuous Production of 5-Hydroxymethylfurfural  

Science Journals Connector (OSTI)

Acid-Functionalized SBA-15-Type Periodic Mesoporous Organosilicas and Their Use in the Continuous Production of 5-Hydroxymethylfurfural ... The activity, selectivity, and stability of several supported acid catalysts were evaluated in tubular reactors designed to produce 5-hydroxymethylfurfural (HMF) continuously from fructose dissolved in a single-phase solution of THF and H2O (4:1 w/w). ... 5-hydroxymethylfurfural; continuous dehydration; packed-bed reactor; SBA-15; periodic mesoporous organosilicas; propylsulfonic acid; catalyst deactivation rate ...

Mark H. Tucker; Anthony J. Crisci; Bethany N. Wigington; Neelay Phadke; Ricardo Alamillo; Jinping Zhang; Susannah L. Scott; James A. Dumesic

2012-07-09T23:59:59.000Z

233

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

234

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

235

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

236

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

237

Synthetic pH Sensor, Protein Nanomaterials, Metabolites in Stem Cells, and DNA Barcodes  

Science Journals Connector (OSTI)

Each month, Chemistry & Biology Select highlights a selection of research reports from the recent literature. These highlights are a snapshot of interesting research done across the field of chemical biology, and this month's Select includes reports on a synthetic pH sensor, a tag that guides assembly of proteins into nanomaterials, a role of an intermediary metabolite in regulation of stem cells, and DNA-barcoded nucleosome libraries.

2014-01-01T23:59:59.000Z

238

Experimental procedures to mitigate electron beam induced artifacts during in situ fluid imaging of nanomaterials  

E-Print Network [OSTI]

of nanomaterials Taylor J. Woehl a,n , Katherine L. Jungjohann a , James E. Evans b,c , Ilke Arslan a,c , William D, USA a r t i c l e i n f o Available online 27 July 2012 Keywords: in situ TEM in situ STEM in situ fluid in situ liquid a b s t r a c t Scanning transmission electron microscopy of various fluid

Ristenpart, William

239

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

240

Defect Migration and Recombination in Nanoindentation of Silica...  

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

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

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

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

242

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

243

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

244

Cryogenic properties of optomechanical silica microcavities  

Science Journals Connector (OSTI)

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

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

2009-08-12T23:59:59.000Z

245

Suspended bridge-like silica 2×2 beam splitter on silicon  

Science Journals Connector (OSTI)

We report a successful experimental realization of a 2×2 suspended silica splitter integrated on a silicon substrate. The silica splitter was photo-lithographically patterned,...

Zhang, Xiaomin; Armani, Andrea M

2011-01-01T23:59:59.000Z

246

Silica Bridge Impact on Hollow-Core Bragg Fiber Transmission Properties  

Science Journals Connector (OSTI)

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

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

247

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

248

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

Science Journals Connector (OSTI)

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

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

2014-12-01T23:59:59.000Z

249

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...

250

Microemulsion-Assisted Synthesis of Mesoporous Aluminum Oxyhydroxide Nanoflakes for Efficient Removal of Gaseous Formaldehyde  

Science Journals Connector (OSTI)

Microemulsion-Assisted Synthesis of Mesoporous Aluminum Oxyhydroxide Nanoflakes for Efficient Removal of Gaseous Formaldehyde ... Add to ACS ChemWorx ... (33) Often, aluminum oxyhydroxide was prepared via hydrothermal or solvothermal processes under high pressure in a sealed autoclave at relatively high temperatures (above 100 °C), in which different additives such as sodium tartrate, sodium amide, and trisodium citrate were used to control its morphology. ...

Zhihua Xu; Jiaguo Yu; Jingxiang Low; Mietek Jaroniec

2014-01-13T23:59:59.000Z

251

Controlled morphogenesis of amorphous silica and its relevance to biosilicification  

Science Journals Connector (OSTI)

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

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

252

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

253

Supercritical carbon dioxide behavior in porous silica aerogel  

Science Journals Connector (OSTI)

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

Ciccariello, S.

2010-11-27T23:59:59.000Z

254

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

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

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

255

Phase behavior of methane hydrate in silica sand  

Science Journals Connector (OSTI)

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

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

2014-01-01T23:59:59.000Z

256

Total Neutron Scattering in Vitreous Silica  

Science Journals Connector (OSTI)

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

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

1957-01-15T23:59:59.000Z

257

Carbon Nanotubes: Artificial Nanomaterials to Engineer Single Neurons and Neuronal Networks  

Science Journals Connector (OSTI)

Carbon Nanotubes: Artificial Nanomaterials to Engineer Single Neurons and Neuronal Networks ... In the past decade, CNTs have been largely investigated as substrates for the development of neuronal circuits; in such a use, the development of a hybrid neuronal–nanomaterial network served also as a platform to examine neuronal detection of and reactions to, environmental physical and chemical features. ... In order to provide stromal support in the case of lesions at the level of the central nervous system (CNS) and to overcome the inhibitory environment (for example, in the case of spinal lesions),(31-33) scaffolds selected for CNS tissue engineering have to be biocompatible with the host tissue without inducing inflammatory and immune reactions, reduce the astrocytic reaction and glial scar formation, allow neuronal adhesion and axonal extension within a three-dimensional architecture, offer proper physical support to cells and axons, provide physical properties similar to the native environment, and have a tunable rate of degradation without inflammation induced by degradation products. ...

Alessandra Fabbro; Susanna Bosi; Laura Ballerini; Maurizio Prato

2012-05-22T23:59:59.000Z

258

Bio-mass derived mesoporous carbon as super electrode in all vanadium redox flow battery with multicouple reactions  

Science Journals Connector (OSTI)

Abstract We first report the multi-couple reaction in all vanadium redox flow batteries (VRFB) while using bio-mass (coconut shell) derived mesoporous carbon as electrode. The presence of V3+/V4+ redox couple certainly supplies the additional electrons for the electrochemical reaction and subsequently provides improved electrochemical performance of VRFB system. The efficient electro-catalytic activity of such coconut shell derived high surface area mesoporous carbon is believed for the improved cell performance. Extensive power and electrochemical studies are performed for VRFB application point of view and described in detail.

Mani Ulaganathan; Akshay Jain; Vanchiappan Aravindan; Sundaramurthy Jayaraman; Wong Chui Ling; Tuti Mariana Lim; M.P. Srinivasan; Qingyu Yan; Srinivasan Madhavi

2014-01-01T23:59:59.000Z

259

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]

2 H 2 CH 3 CH 3 Scheme 2. Ethylene Hydrogenation Reaction. HHydrogenation Reaction. Table 1 Ethylene Hydrogenation RatesCatalytic Activity for Ethylene and Pyrrole Hydrogenation

Huang, Wenyu

2009-01-01T23:59:59.000Z

260

Polymer/Silica Composite Films as Luminescent Oxygen Sensors  

Science Journals Connector (OSTI)

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

Xin Lu; Ian Manners; Mitchell A. Winnik

2001-03-06T23:59:59.000Z

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

Smectic ordering in polymer liquid crystal-silica aerogel nanocomposites  

Science Journals Connector (OSTI)

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

H. Westfahl Jr.

2005-02-01T23:59:59.000Z

262

Different methods to derive pure silica from agriculture waste  

Science Journals Connector (OSTI)

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

Azza El-Maghraby; Heba A. El-Deeb

2012-01-01T23:59:59.000Z

263

Scratch resistance of different silica filled resins for obturation materials  

E-Print Network [OSTI]

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

North Texas, University of

264

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

265

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.

266

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

267

Synthesis and photocatalytic applications of nano-sized zinc-doped mesoporous titanium oxide  

SciTech Connect (OSTI)

Graphical abstract: Nano-sized mesoporous titanium oxide (T0) and zinc-doped nano-sized mesoporous titanium oxides (TA–TD) were synthesized by a simple method and characterized by different techniques. All materials have been studied in the photocatalytic degradation of methylene blue under UV light, observing that the decrease in the band gap of the materials seems to have a positive influence in the photocatalytic activity. Display Omitted Highlights: ? Nano-sized mesoporous TiO{sub 2} and Zn-doped TiO{sub 2} have been synthesized and characterized. ? Band gap of the Zn-doped TiO{sub 2} decreases when the Zn amount increases. ? Materials consist of porous particles (10–20 nm). ? The photocatalytic degradation of MB has been studied for these materials. ? A decrease in the band gap of the materials enhances the photocatalytic activity. -- Abstract: The synthesis of nano-sized mesoporous titanium oxide (T0) is described by an easy synthetic method which consists of the reaction of titanium tetraisopropoxide and a solution of HNO{sub 3} in water (pH 2.0) and the subsequent elimination of the volatiles by simple distillation. On the other hand, zinc-doped mesoporous titanium oxides (TA–TD) were synthesized using the same method but adding increasing amounts of Zn(NO{sub 3}){sub 2} to give materials which contain between 0.12 and 6.17 wt.% Zn. Upon the calcinations of all the obtained materials, characterization has been carried out by using N{sub 2} adsorption–desorption isotherms, powder X-ray diffraction, X-ray fluorescence, UV–vis spectrometry, solid state {sup 47,49}Ti NMR spectroscopy and transmission electronic microscopy (TEM). The results show that all these materials are mesoporous, with BET surfaces between 54 and 121 m{sup 2}/g and similar pore diameters between 6.4 and 9.1 nm. XRD studies show that these materials mainly consist of anatase and very small amounts of brookite. TEM technique shows the small particle sizes of the corresponding materials (from 10 to 20 nm) and the porous structure of parallel and straight channels for T0, TA, TB and TC while the order in the porosity of the system is lost in TD. In addition, studies of the Kubelka-Munk function show that the band gap energy of the synthesized materials decreases with the increase of the Zn amount of the material from 3.24 (for T0) to 2.91 eV (for TD). All the studied materials have been studied in the photocatalytic degradation of methylene blue (MB) under UV light, observing that the decrease in the band gap of the materials seems to have a positive influence in the photocatalytic activity.

Sánchez-Muñoz, Sergio; Pérez-Quintanilla, Damián [Departamento de Química Inorgánica y Analítica, E.S.C.E.T., Universidad Rey Juan Carlos, C/Tulipán s/n, 28933, Móstoles (Madrid) (Spain)] [Departamento de Química Inorgánica y Analítica, E.S.C.E.T., Universidad Rey Juan Carlos, C/Tulipán s/n, 28933, Móstoles (Madrid) (Spain); Gómez-Ruiz, Santiago, E-mail: santiago.gomez@urjc.es [Departamento de Química Inorgánica y Analítica, E.S.C.E.T., Universidad Rey Juan Carlos, C/Tulipán s/n, 28933, Móstoles (Madrid) (Spain)] [Departamento de Química Inorgánica y Analítica, E.S.C.E.T., Universidad Rey Juan Carlos, C/Tulipán s/n, 28933, Móstoles (Madrid) (Spain)

2013-02-15T23:59:59.000Z

268

ADVANCED MATERIALS Curriculum Nanomaterials Materials Science I 5 CP Materials Science II 5 CP Lab Materials Science II 5 CP  

E-Print Network [OSTI]

ADVANCED MATERIALS Curriculum Nanomaterials Materials Science I 5 CP Materials Science II 5 CP Lab Materials Science II 5 CP Computational Methods in Materials Science 4 CP Lab Materials Science I 5 CP Physical Chemistry 4 CP General Chemistry 2 CP Synthesis of Org. & Inorg. Materials 4 CP Introductory Solid

Pfeifer, Holger

269

Self-Assembly of Virus-Structured High Surface Area Nanomaterials and Their Application as Battery Electrodes  

E-Print Network [OSTI]

Self-Assembly of Virus-Structured High Surface Area Nanomaterials and Their Application as Battery templates produced uniform metal coatings up to 40 nm in thickness. Within a nickel-zinc battery system have uses in an array of applications including electrodes, catalyst supports, thermal barriers, sensor

Rubloff, Gary W.

270

Potential of hybrid functionalized meso-porous materials for the separation and immobilization of radionuclides  

SciTech Connect (OSTI)

Functionalized meso-porous materials are a class of hybrid organic-inorganic material in which a meso-porous metal oxide framework is functionalized with multifunctional organic molecules. These molecules may contain one or more anchor groups that form strong bonds to the pore surfaces of the metal oxide framework and free functional groups that can impart and or modify the functionality of the material such as for binding metal ions in solution. Such materials have been extensively studied over the past decade and are of particular interest in absorption applications because of the tremendous versatility in choosing the composition and architecture of the metal oxide framework and the nature of the functional organic molecule as well as the efficient mass transfer that can occur through a well-designed hierarchically porous network. A sorbent for nuclear applications would have to be highly selective for particular radio nuclides, it would need to be hydrolytically and radiolytically stable, and it would have to possess reasonable capacity and fast kinetics. The sorbent would also have to be available in a form suitable for use in a column. Finally, it would also be desirable if once saturated with radio nuclides, the sorbent could be recycled or converted directly into a ceramic or glass waste form suitable for direct repository disposal or even converted directly into a material that could be used as a transmutation target. Such a cradle-to- grave strategy could have many benefits in so far as process efficiency and the generation of secondary wastes are concerned.This paper will provide an overview of work done on all of the above mentioned aspects of the development of functionalized meso-porous adsorbent materials for the selective separation of lanthanides and actinides and discuss the prospects for future implementation of a cradle-to-grave strategy with such materials. (author)

Luca, V. [Programa Nacional de Gestion de Residuos Radiactivos, Comision Nacional de Energia Atomica, Centro Atomico Constituyentes, Av. General, Paz 1499, 1650 San Martin, Provincia de Buenos Aires (Argentina)

2013-07-01T23:59:59.000Z

271

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

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

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

272

Experimental procedures to mitigate electron beam induced artifacts during in situ fluid imaging of nanomaterials  

SciTech Connect (OSTI)

Currently there are few standardized experimental practices in the field of fluid stage transmission electron microscopy. To obtain consistency in this emerging field, a crucial step is to establish the common artifacts and electron beam-sample interactions that can occur. Recently many unintended phenomena have been observed during in situ fluid stage scanning transmission electron microscopy (STEM) experiments, including growth of crystals on the fluid stage windows, repulsion of particles from the irradiated area, bubble formation, and the loss of atomic information during prolonged imaging of individual nanoparticles. Here we provide a comprehensive review of these fluid stage artifacts, and we present new experimental evidence that sheds light on their origins in terms of experimental apparatus issues and indirect electron beam sample interactions with the fluid layer. The results here will provide a methodology for minimizing fluid stage imaging artifacts and acquiring quantitative in situ observations of nanomaterial behavior in a liquid environment.

Woehl, Taylor J.; Jungjohann, K. L.; Evans, James E.; Arslan, Ilke; Ristenpart, William D.; Browning, Nigel D.

2013-04-01T23:59:59.000Z

273

Size effects in Ni/Ni(OH)2 nanomaterials for electrochemical capacitors.  

SciTech Connect (OSTI)

Electrochemical capacitors based on redox-active metal oxides show great promise for many energy-storage applications. These materials store charge through both electric double-layer charging and faradaic reactions in the oxide. The dimensions of the oxide nanomaterials have a strong influence on the performance of such capacitors. Not just due to surface area effects, which influence the double-layer capacitance, but also through bulk electrical and ionic conductivities. Ni(OH)2 is a prime candidate for such applications, due to low cost and high theoretical capacity. We have examined the relationship between diameter and capacity for Ni/Ni(OH)2 nanorods. Specific capacitances of up to 511 F/g of Ni were recorded in 47 nm diameter Ni(OH)2 nanorods.

Bunker, Bruce Conrad; Limmer, Steven J.; Yelton, William Graham

2010-04-01T23:59:59.000Z

274

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

275

Functionalized aerogels – new nanomaterials for energy-efficient building. Preliminary AFM, Nanoidentation and EIS studies  

Science Journals Connector (OSTI)

Aerogels are highly porous nanostructured materials with excellent thermal insulation properties. The possibility to add additional function – to functionalize the aerogels, especially to produce photovoltaic electricity, will make them an excellent candidate for energy-efficient building. Going in the direction of this midterm goal we start with the investigation of the properties of the readily available silica aerogels. Atomic Force Microscopy reveals large areas with submicrometer roughness, which allows reliable nanoidentation measurements. The average hardness was measured to be 2,2 MPa and the Young's modulus was 11 MPa, values typical for low density elastic silica aerogels. Electrochemical Impedance Spectroscopy, measured in ambient air, shows typical capacitive behaviour and the aerogel is best modelled by serially connected resistance of 37 k? and capacitor of 170 pF. The conductivity is interpreted in terms of proton migration, strongly dependant on air humidity.

G R Ivanov; R Tomova; S T Djambova; M Nadoliiski; D Dimova-Malinovska

2010-01-01T23:59:59.000Z

276

In Situ Synthesized Economical Tungsten Dioxide Imbedded in Mesoporous Carbon for Dye-Sensitized Solar Cells As Counter Electrode Catalyst  

Science Journals Connector (OSTI)

In Situ Synthesized Economical Tungsten Dioxide Imbedded in Mesoporous Carbon for Dye-Sensitized Solar Cells As Counter Electrode Catalyst ... As a novel photovoltaic device to convert solar energy to electricity directly, dye-sensitized solar cells (DSCs) have developed considerably over the last 20 years. ...

Mingxing Wu; Xiao Lin; Liang Wang; Wei Guo; Yudi Wang; Jinqiu Xiao; Anders Hagfeldt; Tingli Ma

2011-09-26T23:59:59.000Z

277

Functional carbon nanotube/mesoporous Carbon/MnO2 hybrid network for high-performance supercapacitors  

Science Journals Connector (OSTI)

A functional carbon nanotube/mesoporous carbon/MnO2 hybrid network has been developed successfully through a facile route. The resulting composites exhibited a high specific capacitance of 351 F/g at 1 Ag-1, with intriguing charge/discharge ...

Tao Tao, Ling Zhang, Hao Jiang, Chunzhong Li

2014-01-01T23:59:59.000Z

278

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

279

Three-dimensional reconstruction of liquid phases in disordered mesopores using in situ small-angle scattering  

Science Journals Connector (OSTI)

In situ synchrotron small-angle X-ray scattering is used to investigate wetting transitions of liquids confined in disordered mesoporous materials. A plurigaussian stochastic model is proposed, which enables one to analyze the data in terms of changing interface areas, contact angle and triple-line length.

Gommes, C.J.

2013-03-14T23:59:59.000Z

280

Triclosan removal by laccase immobilized on mesoporous nanofibers: Strong adsorption and efficient degradation  

Science Journals Connector (OSTI)

Abstract Triclosan is difficult to remove or degrade in natural aquatic environment due to its stable chemical structure and low concentration. This study aimed to enhance its removal rate from water through combining the biocatalytic activity of laccase with high adsorption capacity of mesoporous materials. Vinyl-modified poly(acrylic acid)/SiO2 nanofibrous membranes prepared in this work possessed mesoporous structure (pore size 1.73–3.54 nm, pore volume 0.379 cm3/g) and high specific surface area (542.91 m2/g). Laccase was immobilized on the membranes through covalent crosslinking and the enzyme loading was about 417 mg/g. The physical, chemical, biochemical properties of the immobilized laccase and its application in triclosan removal were comprehensively investigated. The immobilized laccase showed better storage stability and higher tolerance to the changes in pH and temperature compared with free laccase. It also exhibited a better performance (65% removal, 2 h) in triclosan removal than free laccase (29.2% removal, 2 h) under the optimum conditions (pH = 4, 30 °C). The results demonstrated that the mesostructure of nanofibers was beneficial for the adsorption and degradation of triclosan. It may provide a new idea for removal of organic pollutants from water environment using enzyme and adsorption technology.

Ran Xu; Yifang Si; Xiaotao Wu; Fengting Li; Bingru Zhang

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.


281

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

282

Hypoxia-mimicking mesoporous bioactive glass scaffolds with controllable cobalt ion release for bone tissue engineering  

Science Journals Connector (OSTI)

Low oxygen pressure (hypoxia) plays an important role in stimulating angiogenesis; there are, however, few studies to prepare hypoxia-mimicking tissue engineering scaffolds. Mesoporous bioactive glass (MBG) has been developed as scaffolds with excellent osteogenic properties for bone regeneration. Ionic cobalt (Co) is established as a chemical inducer of hypoxia-inducible factor (HIF)-1?, which induces hypoxia-like response. The aim of this study was to develop hypoxia-mimicking MBG scaffolds by incorporating ionic Co2+ into MBG scaffolds and investigate if the addition of Co2+ ions would induce a cellular hypoxic response in such a tissue engineering scaffold system. The composition, microstructure and mesopore properties (specific surface area, nano-pore volume and nano-pore distribution) of Co-containing MBG (Co-MBG) scaffolds were characterized and the cellular effects of Co on the proliferation, differentiation, vascular endothelial growth factor (VEGF) secretion, HIF-1? expression and bone-related gene expression of human bone marrow stromal cells (BMSCs) in MBG scaffolds were systematically investigated. The results showed that low amounts of Co (ions into MBG scaffolds is a viable option for preparing hypoxia-mimicking tissue engineering scaffolds and significantly enhanced hypoxia function. The hypoxia-mimicking MBG scaffolds have great potential for bone tissue engineering applications by combining enhanced angiogenesis with already existing osteogenic properties.

Chengtie Wu; Yinghong Zhou; Wei Fan; Pingping Han; Jiang Chang; Jones Yuen; Meili Zhang; Yin Xiao

2012-01-01T23:59:59.000Z

283

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

284

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

285

Molecular oxygen sensors based on photoluminescent silica aerogels  

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

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

286

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

287

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

288

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

Science Journals Connector (OSTI)

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

Joseph Henon; Arnaud Alzina; Joseph Absi…

2013-02-01T23:59:59.000Z

289

From Cradle-to-Grave at the Nanoscale: Gaps in U.S. Regulatory Oversight along the Nanomaterial Life Cycle  

Science Journals Connector (OSTI)

The result is that some forms of engineered nanomaterials may escape federal oversight and rigorous risk review at one or more stages along their life cycle, with the largest gaps occurring at the postmarket stages, and at points of ENM release to the environment. ... Oversight can be improved through pending regulatory reforms, increased research and development for the monitoring, control, and analysis of environmental and end-of-life releases, introduction of periodic re-evaluation of ENM risks, and fostering a “bottom-up” stewardship approach to the responsible management of risks from engineered nanomaterials. ... Regulatory agencies can play a strong role in promoting proactive “bottom-up” risk management and shared responsibility in the oversight of health and environmental risks. ...

Christian E. H. Beaudrie; Milind Kandlikar; Terre Satterfield

2013-05-13T23:59:59.000Z

290

Reinforcement of Silica Aerogels Using Silane-End-Capped Polyurethanes  

Science Journals Connector (OSTI)

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

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

2013-04-23T23:59:59.000Z

291

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.

292

Tailoring Elastic Properties of Silica Aerogels Cross-Linked with Polystyrene  

Science Journals Connector (OSTI)

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

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

2009-02-19T23:59:59.000Z

293

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.

294

Synthesis and Electrochemical Oxygen Reduction of Platinum Nanoparticles Supported on Mesoporous TiO2  

Science Journals Connector (OSTI)

Structural and morphological properties of the prepared electrocatalyst were characterized by X-ray diffraction (XRD), Brunnier Emmet Teller (BET), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDX). ... (1) In recent years, there have been extensive efforts in the development of fuel cell materials (electrode catalysts, membranes, and supports). ... The main characteristics of an ideal support for PEMFC electrocatalysts would be (i) reasonable electrical conductivity; (ii) good metal?carbon interaction; (iii) high surface area; (iv) a mesoporous structure which enables the filling of the ionomer or polymer electrolyte to bring the catalyst particles close to the reactants, thus maximizing the triple-phase interface; (v) good water handling capability, particularly at the cathode side to avoid electrode flooding; (vi) better corrosion resistance, especially at the anode side. ...

Sangaraju Shanmugam; Aharon Gedanken

2009-10-02T23:59:59.000Z

295

Mechanized Silica Nanoparticles: A New Frontier in Theranostic Nanomedicine  

Science Journals Connector (OSTI)

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

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

2011-06-15T23:59:59.000Z

296

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

297

Atmospheric Plasma Deposited Dense Silica Coatings on Plastics  

Science Journals Connector (OSTI)

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

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

2012-11-26T23:59:59.000Z

298

Silica-Supported Tantalum Clusters: Catalyst for Alkane Conversion  

SciTech Connect (OSTI)

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

Nemana ,S.; Gates, B.

2006-01-01T23:59:59.000Z

299

Fabrication of magnetite/silica/titania core-shell nanoparticles  

Science Journals Connector (OSTI)

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

Suh Cem Pang; Sze Yun Kho; Suk Fun Chin

2012-01-01T23:59:59.000Z

300

Formation of Hollow Gallium Nitride Spheres via Silica Sphere Templates  

Science Journals Connector (OSTI)

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

Chun-Neng Lin; Michael H. Huang

2008-12-30T23:59:59.000Z

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

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

302

Surface Aggregate Structure of Nonionic Surfactants on Silica Nanoparticles  

E-Print Network [OSTI]

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

Paris-Sud XI, Université de

303

High-Yield Harvest of Nanofibers/Mesoporous Carbon Composite by Pyrolysis of Waste Biomass and Its Application for High Durability Electrochemical Energy Storage  

Science Journals Connector (OSTI)

Themochemically converting the waste biomass to functional carbon nanomaterials and bio-oil is an environmentally friendly apporach by reducing greenhouse gas emissions and air pollution caused by open burning. ...

Wu-Jun Liu; Ke Tian; Yan-Rong He; Hong Jiang; Han-Qing Yu

2014-11-05T23:59:59.000Z

304

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

305

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

306

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

307

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

308

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

309

Nimesulide adsorbed on silica aerogel using supercritical carbon dioxide  

Science Journals Connector (OSTI)

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

Giuseppe Caputo; Mariarosa Scognamiglio; Iolanda De Marco

2012-01-01T23:59:59.000Z

310

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

311

Silica microparticles precipitation by two processes using supercritical fluids  

Science Journals Connector (OSTI)

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

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

2013-01-01T23:59:59.000Z

312

Mesoporous tantalum oxide as catalyst for dehydration of glucose to 5-hydroxymethylfurfural  

Science Journals Connector (OSTI)

Abstract Mesoporous tantalum oxide was prepared by acid hydrolysis of tantalum penta-ethoxide in the presence of a triblock co-polymer Pluronic L-121, a non-ionic surfactant, at room temperature and subsequent calcination at 550 °C for 6 h. This solid exhibits a suitable specific surface area (79 m2 g?1) and a high acidity (353 ?mol NH3 g?1) with the presence of both Brönsted and Lewis acid sites, demonstrating to be active as solid acid catalyst in the dehydration of glucose to 5-hydroxymethylfurfural (HMF), in a biphasic water/methyl-iso-butyl ketone (MIBK) system. Thus, by using a glucose:catalyst weight ratio of 3:1, a glucose conversion of 69% and a HMF yield of 23% were achieved at 175 °C, and after only 90 min of reaction time. The catalytic process is selective toward HMF, which is preserved from ulterior hydration to levulinic acid. Fructose was also detected as by-product of glucose isomerisation with 14% of selectivity. The catalyst is very stable, since no leaching of tantalum species to the liquid phase was found; moreover, the catalytic performance of this acid solid is well recovered after calcination at 550 °C for 2 h.

I. Jiménez-Morales; M. Moreno-Recio; J. Santamaría-González; P. Maireles-Torres; A. Jiménez-López

2014-01-01T23:59:59.000Z

313

Microstructural and magnetic characterizations of CoFeCu electrodeposited in self-assembled mesoporous silicon  

Science Journals Connector (OSTI)

Abstract Self-assembled mesoporous silicon with quasi-regular pore arrangements has been fabricated by the electrochemical anodization process in hydrofluoric acid solution. CoFeCu was electrodeposited in this structure from a bath containing sodium acetate as a complexing agent with a pH value of 5. The effect of current density on the morphology, the structure and the magnetic properties of CoFeCu deposit was studied by SEM, EDS, DRX and VSM. It has been shown that the morphology and structure of samples were strongly influenced by the current density and etching duration. The micrographs show the vertical and branched nanowires and also a discontinuous growth of wires. Further, the growth of a thick layer from the grain boundaries of released CoFeCu wires is produced. The magnetic hysteresis loops demonstrate that the CoFeCu nanowires exhibit easy magnetic axis perpendicular to the PS channels axis when the current density varied from 3 to 10 mA/cm2. Nevertheless, they reveal a no magnetic anisotropy of CoFeCu nanostructures deposited only in the outside of porous silicon, probably due to the vanishing the shape anisotropy.

G. Fortas; N. Haine; S. Sam; N. Gabouze; A. Saifi; S. Ouir; H. Menari

2015-01-01T23:59:59.000Z

314

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

315

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

316

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

317

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

318

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...

319

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

Science Journals Connector (OSTI)

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

320

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

Science Journals Connector (OSTI)

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

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

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

Improving the Performance of Heat Insulation Polyurethane Foams by Silica Nanoparticles  

Science Journals Connector (OSTI)

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

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

2009-01-01T23:59:59.000Z

322

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

E-Print Network [OSTI]

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

Giannini, Eric Richard

2012-01-01T23:59:59.000Z

323

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

E-Print Network [OSTI]

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

Kreitman, Kerry Lynn

2011-01-01T23:59:59.000Z

324

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

325

Role of Cs on Hydrodesulfurization Activity of RuS2 Catalysts Supported on a Mesoporous SBA-15 Type Material  

Science Journals Connector (OSTI)

Role of Cs on Hydrodesulfurization Activity of RuS2 Catalysts Supported on a Mesoporous SBA-15 Type Material ... Ruthenium(III) chloride, RuCl3·nH2O (? 41 wt % Ru, from Fluka); cesium hydroxide, CsOH (50 wt % solution, from Aldrich); and cesium chloride, CsCl (99.9% from Aldrich) were employed as ruthenium and cesium precursor salts, respectively. ... These liquid samples were kept in sealed vials and subsequently analyzed by gas chromatography (Shimadzu GC-14B, equipped with a flame ionization detector and a capillary column, TBR-14, coupled to an automatic Shimadzu AOC-20i injector). ...

A. Infantes-Molina; A. Romero-Pe?rez; V. Sa?nchez-Gonza?lez; B. Pawelec; J. L.G. Fierro; A. Jime?nez-Lo?pez; E. Rodri?guez-Castello?n

2011-02-03T23:59:59.000Z

326

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

327

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

328

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

329

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

330

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

331

Chemical treatment for silica-containing glass surfaces  

DOE Patents [OSTI]

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

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

1999-01-01T23:59:59.000Z

332

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

333

Efficient Photoinduced Charge Injection from Chemical Bath Deposited CdS into Mesoporous TiO2 Probed with Time-Resolved Microwave Conductivity  

Science Journals Connector (OSTI)

We use the contactless time-resolved microwave conductivity (TRMC) technique to investigate the photoconductance of CdS-coated mesoporous TiO2 and ZrO2. The CdS domains were grown directly on the surface of the oxide by a chemical bath deposition method. ...

Jorge Piris; Andrew J. Ferguson; Jeff L. Blackburn; Andrew G. Norman; Garry Rumbles; Don C. Selmarten; Nikos Kopidakis

2008-04-24T23:59:59.000Z

334

One-Pot Synthesis of 5-Hydroxymethylfurfural by Cellulose Hydrolysis over Highly Active Bimodal Micro/Mesoporous H-ZSM-5 Catalyst  

Science Journals Connector (OSTI)

One-Pot Synthesis of 5-Hydroxymethylfurfural by Cellulose Hydrolysis over Highly Active Bimodal Micro/Mesoporous H-ZSM-5 Catalyst ... Direct synthesis of 5-hydroxymethylfurfural (5-HMF), a useful renewable biofuel and biochemical, was systematically studied by hydrolysis of microcrystalline cellulose over Bimodal-HZ-5 zeolite. ... Microcrystalline cellulose; Hydrolysis; Biomodal-HZ-5; Glucose; 5-Hydroxymethylfurfural ...

Kakasaheb Y. Nandiwale; Nitish D. Galande; Pratika Thakur; Sanjay D. Sawant; Vishal P. Zambre; Vijay V. Bokade

2014-06-16T23:59:59.000Z

335

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

336

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

Science Journals Connector (OSTI)

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

Lorenzo Stievano; Ling Yu Piao; Irène Lopes; Ming Meng; Dominique Costa; Jean-François Lambert

337

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.

338

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

339

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.

340

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

Science Journals Connector (OSTI)

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

1960-01-01T23:59:59.000Z

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

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

E-Print Network [OSTI]

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

Wang, Zhong L.

342

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

343

Developing a process for commercial silica production from Salton Sea brines  

SciTech Connect (OSTI)

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

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

2000-09-25T23:59:59.000Z

344

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

E-Print Network [OSTI]

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

Lu, Chang

345

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

346

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

E-Print Network [OSTI]

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

347

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

348

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

E-Print Network [OSTI]

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

Brest, Université de

349

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

Science Journals Connector (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 13C 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.

2014-01-01T23:59:59.000Z

350

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

Science Journals Connector (OSTI)

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

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

2013-01-01T23:59:59.000Z

351

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

Science Journals Connector (OSTI)

In the \\{LHCb\\} experiment at the Large Hadron Collider, powerful charged particle identification is performed by Ring Imaging \\{CHerenkov\\} (RICH) technology. In order to cover the full geometric acceptance and the wide momentum range (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 ranges, gas radiators are used (C4F10 and CF4, respectively). In the low momentum range (1–10 GeV/c), pion, kaon and proton separation is performed with solid silica aerogel radiator. A set of 16 tiles, with large transverse dimensions of up to 200 × 200 mm 2 and nominal refractive index 1.03 have been produced and integrated in the detector. These tiles have excellent optical properties and homogeneity of the refractive index at the percent level within the tile. The first data collected at the LHC are used to investigate the behaviour of the RICH; preliminary results of the performance of silica aerogel are presented and discussed.

D.L. Perego

2011-01-01T23:59:59.000Z

352

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

353

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

Science Journals Connector (OSTI)

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

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

354

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

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

Preparation of Activated Carbon and Silica Particles from Rice Straw  

Science Journals Connector (OSTI)

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

Sixiao Hu; You-Lo Hsieh

2014-02-21T23:59:59.000Z

357

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

358

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

SciTech Connect (OSTI)

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

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

1995-02-01T23:59:59.000Z

359

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

360

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

E-Print Network [OSTI]

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

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

1999-11-17T23:59:59.000Z

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

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

362

Gram-Scale Synthesis of Graphene-Mesoporous SnO2 Composite as Anode for Lithium-ion Batteries  

Science Journals Connector (OSTI)

Abstract The gram-scale synthesis of graphene based mesoporous SnO2 composite (G-M-SnO2) has been successfully realized based on kirkendall effect. When used as anode for lithium ion batteries, it delivers a high reversible capacity of 1354 mAhg?1 after 50 cycles at 100 mAg?1 and excellent rate capability of 664 mAhg?1 at 2 Ag?1. The outstanding lithium storage performance mainly results from the synergistic effect of the ultrasmall SnO2 and conductive graphene nanoparticles, which not only enhanced the conductivity of the whole electrode but also provide buffer matrix for the expansion of SnO2 nanoparticles during charge-discharge process. Furthermore, the ultra-small size of SnO2 shortens the diffusion length of Li+/e? in SnO2.

Xiaowu Liu; Xiongwu Zhong; Zhenzhong Yang; Fusen Pan; Lin Gu; Yan Yu

2015-01-01T23:59:59.000Z

363

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

364

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

Science Journals Connector (OSTI)

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

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

2006-05-01T23:59:59.000Z

365

Effect of gel parameters on monolithicity and density of silica aerogels  

Science Journals Connector (OSTI)

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

A. Venkateswara Rao; N. N. Parvathy

1993-06-01T23:59:59.000Z

366

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

Science Journals Connector (OSTI)

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

Masayuki Nogami; Shohei Hotta…

2010-11-01T23:59:59.000Z

367

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...

368

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...

369

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

370

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

Science Journals Connector (OSTI)

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

Christoph Gerhard; Tobias Weihs; Daniel Tasche…

2013-10-01T23:59:59.000Z

371

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

E-Print Network [OSTI]

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

Eck, Mary

2012-07-16T23:59:59.000Z

372

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

Science Journals Connector (OSTI)

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

Suzuki, Naoaki; Tomita, Yasuo

2004-01-01T23:59:59.000Z

373

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

374

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

E-Print Network [OSTI]

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

Eck, Mary

2012-01-01T23:59:59.000Z

375

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,...

376

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

SciTech Connect (OSTI)

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

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

2011-12-15T23:59:59.000Z

377

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

378

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

Science Journals Connector (OSTI)

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

Vollet, D.R.

2008-11-28T23:59:59.000Z

379

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

380

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

SciTech Connect (OSTI)

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

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

1993-10-01T23:59:59.000Z

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

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

SciTech Connect (OSTI)

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

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

2012-12-15T23:59:59.000Z

382

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

Science Journals Connector (OSTI)

Abstract In this work, a series of cellulose acetate/polyethylene glycol-600 membranes, with varying ratios were prepared by 2-stage phase inversion protocol. The permeation properties were studied by subjecting membranes in indigenously fabricated reverse osmosis plant. After optimization of different CA/PEG ratios, the membrane with highest salt rejection capacity was selected and modified with varying amount of silica. The Modified membranes were characterized for their permeation properties, hydrophilicity, compositional analysis, thermal stability, mechanical strength and morphological studies. Silica significantly influenced the permeation performance of composite membrane. The flux enhanced from 0.35 to 2.46 L/h m2 along with an 11.41% relative increase in salt rejection. The hydrophilicity was significantly enhanced by the addition of silica. In FTIR spectra, the broadening of the peak around 3500 cm? 1 and emergence of peak at 950 cm? 1 specified the incorporation of silica particles. The thermal analysis indicated the relative increase in degradation temperature (Tmax) and glass transition temperature (Tg) for CPS-5 membrane. The mechanical stability of the modified membranes, increased initially, but declined with further addition of silica. The results indicated that the incorporation of SiO2 content in the casting solution improved the fouling resistance of the membranes.

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

2015-01-01T23:59:59.000Z

383

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

SciTech Connect (OSTI)

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

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

2010-12-15T23:59:59.000Z

384

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

SciTech Connect (OSTI)

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

Hare, D E; Managan, R A

2005-11-17T23:59:59.000Z

385

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

SciTech Connect (OSTI)

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

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

2006-05-17T23:59:59.000Z

386

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

387

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

388

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

Science Journals Connector (OSTI)

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

Seyed-Ataollah Mirshafiei-Langari; Vahid haddadi-Asl…

2013-05-01T23:59:59.000Z

389

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.

390

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

Science Journals Connector (OSTI)

Abstract Amine–silica adsorbents are considered alternatives to aqueous solutions of amines, which have been traditionally used to capture carbon dioxide (CO2) from flue gas. Among amine–silica adsorbents, polyethyleneimine (PEI)-silica is particularly effective at capturing CO2 from flue gas due to its high thermal stability. In this study, we investigated the influence of PEI type (i.e. branched vs. linear) and molecular weight on the CO2 capture performance of PEI-silica adsorbents. PEI molecular weight influenced the thermal stability of PEI-silica adsorbents; however, when the molecular weight was ?1200 Da the increase in stability was negligible in the temperature range of 25–160 °C. Branched \\{PEIs\\} (BPEIs) achieved higher CO2 saturated sorption capacities compared to linear \\{PEIs\\} (LPEIs); however, \\{LPEIs\\} were more stable than \\{BPEIs\\} during CO2 sorption–desorption cycling. PEI molecular weight also influenced the CO2 saturated sorption capacity; CO2 saturated sorption capacity decreased as PEI molecular weight increased, and among the adsorbents tested in this study BPEI/800-silica had the highest CO2 saturated sorption capacity (202 mg CO2/g adsorbent). Both PEI type and molecular weight exhibited influence on the sorption or desorption heat of PEI-silica adsorbents. The CO2 regeneration heat was much lower than that of MEA solution for all PEI-silica adsorbents tested in this study.

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

2014-01-01T23:59:59.000Z

391

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

392

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

393

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

394

The exchange rate for tritiated water vapor adsorbed on silica gel  

E-Print Network [OSTI]

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

Shamblin, Penny Alane

2012-06-07T23:59:59.000Z

395

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

396

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

397

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

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

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

398

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

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

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

399

Soft-Template Simple Synthesis of Ordered Mesoporous Titanium Nitride-Carbon Nanocomposite for High Performance Dye-Sensitized Solar Cell Counter Electrodes  

Science Journals Connector (OSTI)

(1-3, 6, 7) Owing to these advantages, TiNs can be widely used in different fields as catalysts(8-10) or as parts of certain energy-generating devices, such as dye-sensitized solar cells,(11, 12) fuel cells,(13, 14) and supercapacitors. ... To overcome the disadvantages of the hard template-methods, soft-template approaches have been widely exploited to obtain ordered mesoporous carbons or metal oxides. ... The surface energies and surface relaxations of the three most important surfaces of TiN were studied. ...

Easwaramoorthi Ramasamy; Changshin Jo; Arockiam Anthonysamy; Inyoung Jeong; Jin Kon Kim; Jinwoo Lee

2012-04-06T23:59:59.000Z

400

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

SciTech Connect (OSTI)

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

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

2003-06-18T23:59:59.000Z

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

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

Science Journals Connector (OSTI)

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

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

2011-01-01T23:59:59.000Z

402

Density hysteresis of heavy water confined in a nanoporous silica matrix  

E-Print Network [OSTI]

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

Zhang, Yang

403

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

SciTech Connect (OSTI)

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

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

2012-04-15T23:59:59.000Z

404

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.

405

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

SciTech Connect (OSTI)

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

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

1991-02-01T23:59:59.000Z

406

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

407

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

408

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

409

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

Science Journals Connector (OSTI)

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

Sebastian Röder; Stephan Hobe; Harald Paulsen

2014-11-03T23:59:59.000Z

410

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

E-Print Network [OSTI]

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

411

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

Science Journals Connector (OSTI)

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

Konstantinos D. Demadis; Maria Somara; Eleftheria Mavredaki

2012-01-20T23:59:59.000Z

412

Silica–titania aerogel monoliths with large pore volume and surface area by ambient pressure drying  

Science Journals Connector (OSTI)

Ambient pressure drying has been carried out for the synthesis of silica–titania aerogel monoliths. The prepared aerogels show densities in the range 0.34–0.38 g/cm3. The surface area and pore volume of these mix...

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

2009-12-01T23:59:59.000Z

413

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

Science Journals Connector (OSTI)

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

Miriam Rueda; Luis Miguel Sanz-Moral; Antonio Nieto-Márquez; Pablo Longone; Facundo Mattea; Ángel Martín

2014-01-01T23:59:59.000Z

414

Application of stochastic weighted algorithms to a multidimensional silica particle model  

SciTech Connect (OSTI)

Highlights: •Stochastic weighted algorithms (SWAs) are developed for a detailed silica model. •An implementation of SWAs with the transition kernel is presented. •The SWAs’ solutions converge to the direct simulation algorithm’s (DSA) solution. •The efficiency of SWAs is evaluated for this multidimensional particle model. •It is shown that SWAs can be used for coagulation problems in industrial systems. -- Abstract: This paper presents a detailed study of the numerical behaviour of stochastic weighted algorithms (SWAs) using the transition regime coagulation kernel and a multidimensional silica particle model. The implementation in the SWAs of the transition regime coagulation kernel and associated majorant rates is described. The silica particle model of Shekar et al. [S. Shekar, A.J. Smith, W.J. Menz, M. Sander, M. Kraft, A multidimensional population balance model to describe the aerosol synthesis of silica nanoparticles, Journal of Aerosol Science 44 (2012) 83–98] was used in conjunction with this coagulation kernel to study the convergence properties of SWAs with a multidimensional particle model. High precision solutions were calculated with two SWAs and also with the established direct simulation algorithm. These solutions, which were generated using large number of computational particles, showed close agreement. It was thus demonstrated that SWAs can be successfully used with complex coagulation kernels and high dimensional particle models to simulate real-world systems.

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

2013-09-01T23:59:59.000Z

415

Enhanced green upconversion luminescence in Yb–Tb co-doped sintered silica nanoporous glass  

Science Journals Connector (OSTI)

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

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

2014-11-01T23:59:59.000Z

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

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

418

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

419

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

420

Oxygen isotope fractionation between amorphous silica and water at 34–93°C  

Science Journals Connector (OSTI)

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

Itsuro Kita; Sachihiro Taguchi; Osamu Matsubaya

1985-03-07T23:59:59.000Z

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

Sodium-Silicate Route to Submicrometer Hybrid PEG@Silica Particles  

Science Journals Connector (OSTI)

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

Hila Elimelech; David Avnir

2008-03-04T23:59:59.000Z

422

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

E-Print Network [OSTI]

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

Guo, John Zhanhu

423

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

E-Print Network [OSTI]

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

Matthewson, M. John

424

Thulium-doped silica fibers with enhanced 3 H4 level lifetime  

E-Print Network [OSTI]

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

Paris-Sud XI, Université de

425

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

426

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

E-Print Network [OSTI]

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

Guo, Ting

427

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

428

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

Science Journals Connector (OSTI)

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

D. Sanli; C. Erkey

2013-10-29T23:59:59.000Z

429

9422 Stratospheric ice catalyzes chlorine reactions 9428 Fusing silk and silica  

E-Print Network [OSTI]

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

McFadden, Geoff

430

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

Science Journals Connector (OSTI)

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

Peter E. Blöchl

2000-09-01T23:59:59.000Z

431

Study of pure-silica Zeolite Nucleation and Growth from Solution  

E-Print Network [OSTI]

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

Li, Xiang

2011-10-21T23:59:59.000Z

432

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

E-Print Network [OSTI]

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

Matthewson, M. John

433

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

434

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

435

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

Science Journals Connector (OSTI)

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

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

2012-01-01T23:59:59.000Z

436

Nanomaterials for Defense Applications  

Science Journals Connector (OSTI)

Nanotechnology has found a number of applications in electronics and healthcare. Within the textile field, applications of nanotechnology have been limited to filters, protective liners for chemical and biolog...

Uday Turaga; Vinitkumar Singh…

2012-01-01T23:59:59.000Z

437

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

438

Hydrogen production by steam reforming of liquefied natural gas (LNG) over mesoporous Ni–La–Al2O3 aerogel catalysts: Effect of La content  

Science Journals Connector (OSTI)

Mesoporous Ni–La–Al2O3 aerogel catalysts (denoted as (40-x)NixLa) with different lanthanum content (x) were prepared by a single-step sol-gel method and a subsequent CO2 supercritical drying method. The effect of lanthanum content on the physicochemical properties and catalytic performance of mesoporous (40-x)NixLa catalysts in the steam reforming of liquefied natural gas (LNG) was investigated. Physicochemical properties of (40-x)NixLa catalysts were strongly influenced by lanthanum content. Dispersion and reducibility of nickel aluminate phase in the (40-x)NixLa catalysts increased with increasing lanthanum content. Small amount of lanthanum addition was effective for dispersion of metallic nickel in the (40-x)NixLa catalysts, but large amount of lanthanum addition was not favorable for nickel dispersion due to the blocking of active sites. In the steam reforming of LNG, both LNG conversion and hydrogen yield showed volcano-shaped curves with respect to lanthanum content. Average nickel diameter of (40-x)NixLa catalysts was well correlated with LNG conversion and hydrogen yield over the catalysts. Among the catalysts tested, 36Ni4La (36 wt% Ni and 4 wt% La) catalyst with the smallest average nickel diameter exhibited the best catalytic performance and the strongest resistance toward carbon deposition in the steam reforming of LNG.

Yongju Bang; Jeong Gil Seo; In Kyu Song

2011-01-01T23:59:59.000Z

439

Mesoporous Pt–Co oxygen reduction reaction (ORR) catalysts for low temperature proton exchange membrane fuel cell synthesized by alternating sputtering  

Science Journals Connector (OSTI)

Abstract Mesoporous catalysts with enhanced oxygen reduction reaction (ORR) activity for PEM fuel cells are synthesized by alternating sputtering of Pt and Co onto gas diffusion layers with microporous layers. Co is acting as a template for synthesis of a porous Pt nanostructure. For such proposed Pt–Co catalysts the kinetic current in the ORR was found to be increased by a factor of up to 16 and the mass specific current in PEM single cells by a factor of up to 7. Co was found to be deposited at the grain boundary of the Pt layer and dissolves under acidic conditions resulting in a mesoporous Pt catalyst which is advantageous for gas diffusion catalysts. Microstructural and compositional parameters were optimised in order to obtain a high kinetic current and lower onset potential for the ORR. The most favourable Co layer thickness was determined to be 2 nm. The optimal Pt–Co catalyst can be synthesized by continuously varying the Pt layer thickness. The highest Pt mass activity was found at a layer thickness of 30.5 nm. Catalysts were characterised by SEM, EDX, electrochemical half cell and PEM single cell tests.

Gustav Sievers; Steffen Mueller; Antje Quade; Florian Steffen; Sven Jakubith; Angela Kruth; Volker Brueser

2014-01-01T23:59:59.000Z

440

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

Office of Scientific and Technical Information (OSTI)

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

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

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

Office of Scientific and Technical Information (OSTI)

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

442

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

Office of Scientific and Technical Information (OSTI)

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

443

CURRICULUM VITAE March 2012 Teddy (Tewodros) Asefa  

E-Print Network [OSTI]

; nanoelectronics; nanomaterials for solar cells and renewable energy; inorganic-organic nanocomposites. Dirshaye Menberu Research Report: Organic natural products - Isolation and Characterization of Anthochlor Dissertation: Periodic Mesoporous Organosilicas - A New Class of Hybrid Organic-Inorganic Nanocomposites M

Lawson, Catherine L.

444

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

Science Journals Connector (OSTI)

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

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

445

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

Science Journals Connector (OSTI)

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

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

1994-01-01T23:59:59.000Z

446

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

Science Journals Connector (OSTI)

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

Gerhard, Christoph; Tasche, Daniel; Brückner, Stephan; Wieneke, Stephan; Viöl, Wolfgang

2012-01-01T23:59:59.000Z

447

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

E-Print Network [OSTI]

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

448

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

Science Journals Connector (OSTI)

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

Ira Ben Shir; Shifi Kababya; Asher Schmidt

2012-04-12T23:59:59.000Z

449

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

Science Journals Connector (OSTI)

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

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

2012-01-01T23:59:59.000Z

450

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

451

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

Science Journals Connector (OSTI)

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

Koichi Sawada, Shinji Sakai, Masahito Taya

2014-01-01T23:59:59.000Z

452

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

453

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

454

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

455

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

456

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

457

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

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

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

460

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

Science Journals Connector (OSTI)

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

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

2013-08-13T23:59:59.000Z

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

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

Science Journals Connector (OSTI)

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

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

2011-07-13T23:59:59.000Z

462

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

Science Journals Connector (OSTI)

Magnetic Silica Nanotubes: Synthesis, Drug Release, and Feasibility for Magnetic Hyperthermia ... After removal of RhB@?-Fe2O3@SiO2 by magnet, 3 mL of the clear solution was extracted with a syringe at given time intervals and then analyzed by UV–vis spectroscopy at a wavelength of 400–1000 nm. ... The work was supported by Foundation for Polish Science within Focus with contract F4/2010. ...

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

2012-04-09T23:59:59.000Z

463

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

464

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

465

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

466

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

E-Print Network [OSTI]

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

Paris-Sud XI, Université de

467

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

E-Print Network [OSTI]

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

Paris-Sud XI, Université de

468

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

Science Journals Connector (OSTI)

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

Prass, J.

2012-07-04T23:59:59.000Z

469

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

Science Journals Connector (OSTI)

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

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

1992-08-03T23:59:59.000Z

470

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

SciTech Connect (OSTI)

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

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

2005-10-24T23:59:59.000Z

471

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

Science Journals Connector (OSTI)

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

Mahesh Sachithanadam; Sunil Chandrakanth Joshi

2014-01-01T23:59:59.000Z

472

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

Science Journals Connector (OSTI)

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

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

2008-01-01T23:59:59.000Z

473

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

SciTech Connect (OSTI)

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

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

1998-11-10T23:59:59.000Z

474

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

SciTech Connect (OSTI)

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

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

2006-03-01T23:59:59.000Z

475

Sol-gel synthesis of mesoporous CaCu{sub 3}Ti{sub 4}O{sub 12} thin films and their gas sensing response  

SciTech Connect (OSTI)

A new sol-gel synthesis procedure of stable calcium copper titanate (CaCu{sub 3}Ti{sub 4}O{sub 12}-CCTO) precursor sols for the fabrication of porous films was developed. The composition of the sol was selected in order to avoid the precipitation of undesired phases; ethanol was used as solvent, acetic acid as modifier and poly(ethyleneglycol) as a linker agent. Films deposited by spin-coating onto oxidized silicon substrates were annealed at 700 {sup o}C. The main phase present in the samples, as detected by X-ray diffraction and Raman spectroscopy, was CaCu{sub 3}Ti{sub 4}O{sub 12}. Scanning electron microscopy analysis showed that mesoporous structures, with thicknesses between 200 and 400 nm, were developed as a result of the processing conditions. The films were tested regarding their sensibility towards oxygen and nitrogen at atmospheric pressure using working temperatures from 200 to 290 {sup o}C. The samples exhibited n-type conductivity, high sensitivity and short response times. These characteristics indicate that CCTO mesoporous structures obtained by sol-gel are suitable for application in gas sensing. - Graphical abstract: A sol-gel synthesis procedure toward stable CaCu{sub 3}Ti{sub 4}O{sub 12}-precursor sols avoiding the precipitation of undesired compounds is proposed. Films deposited by spin-coating onto oxidized silicon substrates were annealed at 700 {sup o}C. The thickness varied between 200 and 400 nm depending on sol composition. The films, tested as gas sensors for O{sub 2}, showed n-type conductivity, good sensitivity and short response times.

Parra, R., E-mail: rparra@fi.mdp.edu.a [Instituto de Investigaciones en Ciencia y Tecnologia de Materiales (INTEMA), CONICET-UNMdP, J. B. Justo 4302, B7608FDQ Mar del Plata (Argentina); Savu, R. [Instituto de Quimica, UNESP, Rua F. Degni s/n, 14800-900 Araraquara, SP (Brazil); Ramajo, L.A.; Ponce, M.A. [Instituto de Investigaciones en Ciencia y Tecnologia de Materiales (INTEMA), CONICET-UNMdP, J. B. Justo 4302, B7608FDQ Mar del Plata (Argentina); Varela, J.A. [Instituto de Quimica, UNESP, Rua F. Degni s/n, 14800-900 Araraquara, SP (Brazil); Castro, M.S. [Instituto de Investigaciones en Ciencia y Tecnologia de Materiales (INTEMA), CONICET-UNMdP, J. B. Justo 4302, B7608FDQ Mar del Plata (Argentina); Bueno, P.R. [Instituto de Quimica, UNESP, Rua F. Degni s/n, 14800-900 Araraquara, SP (Brazil); Joanni, E. [Instituto de Quimica, UNESP, Rua F. Degni s/n, 14800-900 Araraquara, SP (Brazil); Centro de Tecnologia da Informacao Renato Archer, Rodovia Dom Pedro I (SP-65) km 143, 6, 13069-901 Campinas, SP (Brazil)

2010-06-15T23:59:59.000Z

476

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

477

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

E-Print Network [OSTI]

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

Rust, Charles Karissa

2009-01-01T23:59:59.000Z

478

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

SciTech Connect (OSTI)

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

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

2006-08-28T23:59:59.000Z

479

Water purification by functionalised self-assembled monolayers on silica particles  

Science Journals Connector (OSTI)

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

Peter J. Majewski; Chiu Ping Chan

2008-01-01T23:59:59.000Z

480

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

Science Journals Connector (OSTI)

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

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

2009-02-11T23:59:59.000Z

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.


481

Applications for silica-based aerogel products on an industrial scale  

SciTech Connect (OSTI)

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

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

1998-12-31T23:59:59.000Z

482

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

SciTech Connect (OSTI)

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

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

2006-09-13T23:59:59.000Z

483

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

484

Impact of Pt loading methods over mesoporous-assembled TiO{sub 2}–ZrO{sub 2} mixed oxide nanocrystal on photocatalytic dye-sensitized H{sub 2} production activity  

SciTech Connect (OSTI)

Graphical abstract: The Pt loading on the synthesized mesoporous-assembled 0.95TiO{sub 2}–0.05ZrO{sub 2} mixed oxide nanocrystal photocatalyst was comparatively investigated by two methods: single-step sol–gel (SSSG) and photochemical deposition (PCD). The Pt loading by the PCD method was found to be superior to that by the SSSG method in enhancing photocatalytic sensitized hydrogen production under visible light irradiation. The Pt loading amount and PCD conditions, i.e. light irradiation time and light intensity, also had a strong effect on the photocatalytic hydrogen production activity. Highlights: ? Pt-loaded mesoporous-assembled 0.95TiO{sub 2}–0.05ZrO{sub 2} nanocrystals were synthesized. ? Pt loading was performed by single-step sol–gel and photochemical deposition. ? Pt loading by photochemical deposition more enhanced photocatalytic H{sub 2} production. ? Pt loading amount and photochemical deposition conditions were optimized. -- Abstract: In this work, the photocatalytic water splitting under visible light irradiation for hydrogen production was investigated by using Eosin Y-sensitized Pt-loaded mesoporous-assembled TiO{sub 2}–ZrO{sub 2} mixed oxide nanocrystal photocatalysts. The mesoporous-assembled TiO{sub 2}–ZrO{sub 2} mixed oxide with the TiO{sub 2}-to-ZrO{sub 2} molar ratio of 95:5 (i.e. 0.95TiO{sub 2}–0.05ZrO{sub 2}) was synthesized by using a sol–gel process with the aid of a structure-directing surfactant. The Pt loading was comparatively performed via two different effective methods: single-step sol–gel (SSSG) and photochemical deposition (PCD). The synthesized photocatalysts were methodically characterized by N{sub 2} adsorption–desorption, XRD, UV–visible spectroscopy, SEM–EDX, TEM–EDX, TPR, and H{sub 2} chemisorption analyses. The results revealed that the Pt loading by the PCD method greatly enhanced the photocatalytic hydrogen production activity of the synthesized mesoporous-assembled 0.95TiO{sub 2}–0.05ZrO{sub 2} mixed oxide photocatalyst more than that by the SSSG method. The optimum Pt loading by the PCD method was experimentally observed at 0.5 wt.%, which was well associated with the maximum Pt dispersion. In addition, the PCD conditions, i.e. UV light irradiation time and UV light intensity, were investigated and optimized to be 2 h and 44 W, respectively.

Sreethawong, Thammanoon, E-mail: tsreethawong@hotmail.com [Baan Klangmuang Luzern, Soi On-nut 46, Sukhumvit 77 Road, Suanluang, Bangkok 10250 (Thailand)] [Baan Klangmuang Luzern, Soi On-nut 46, Sukhumvit 77 Road, Suanluang, Bangkok 10250 (Thailand); Yoshikawa, Susumu [Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011 (Japan)] [Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011 (Japan)

2012-06-15T23:59:59.000Z

485

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

E-Print Network [OSTI]

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

Sparks, Donald L.

486

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

487

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

SciTech Connect (OSTI)

A developed formalism for analyzing the power scaling of diffraction limited fiber lasers and amplifiers is applied to a wider range of materials. Limits considered include thermal rupture, thermal lensing, melting of the core, stimulated Raman scattering, stimulated Brillouin scattering, optical damage, bend induced limits on core diameter and limits to coupling of pump diode light into the fiber. For conventional fiber lasers based upon silica, the single aperture, diffraction limited power limit was found to be 36.6kW. This is a hard upper limit that results from an interaction of the stimulated Raman scattering with thermal lensing. This result is dependent only upon physical constants of the material and is independent of the core diameter or fiber length. Other materials will have different results both in terms of ultimate power out and which of the many limits is the determining factor in the results. Materials considered include silica doped with Tm and Er, YAG and YAG based ceramics and Yb doped phosphate glass. Pros and cons of the various materials and their current state of development will be assessed. In particular the impact of excess background loss on laser efficiency is discussed.

Dawson, J W; Messerly, M J; Heebner, J E; Pax, P H; Sridharan, A K; Bullington, A L; Beach, R J; Siders, C W; Barty, C P; Dubinskii, M

2010-03-30T23:59:59.000Z

488

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

Science Journals Connector (OSTI)

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

J. L. Blin; C. Gérardin; C. Carteret; L. Rodehüser; C. Selve; M. J. Stébé

2005-02-25T23:59:59.000Z

489

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

E-Print Network [OSTI]

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

Huang, Yanyi

490

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

E-Print Network [OSTI]

Atomistic simulation of the interface structure of Si nanocrystals embedded in amorphous silica 11 February 2008; published 14 March 2008 An efficient means to obtain light emission from a silicon in industrial wafer manufacturing lines, this has opened up a promising avenue for using low-cost silicon chips

Nordlund, Kai

491

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

E-Print Network [OSTI]

1 Replication of butterfly wing and natural lotus leaf nanostructures by nanoimprint on Silica Sol these biomimetics structures over large scales and at affordable price for industrial applications as for example have chosen to imprint the lotus leaf and butterfly wings in order to obtain superhydrophobic surfaces

492

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

E-Print Network [OSTI]

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

Kokkoli, Efie

493

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

Science Journals Connector (OSTI)

A method for making fused silica core?borosilicate clad optical fiberwaveguides is described. The process involves the growth of a needlelike layer of borosilicate glass onto the surface of a commercially available high?purity fused silica rod by an efficient flamereaction of boron and silicon hydrides with oxygen. The needlelike layer is subsequently heat treated at relatively low temperature to form a homogeneous bubble?free glass with a smooth surface. It is then covered with a thin protective jacket of silica and drawn into a fiber. These fibers have attenuation coefficients only slightly greater than the bulk loss of the fused silica core materials. Over the Al1?x Ga x As injection laser wavelength range 0.82–0.88 ?m the loss is 5 dB/km while at the YAG : Nd laser wavelength 1.06 ?m it is 3 dB/km. The process appears to be attractive for the economical manufacture of low?loss fibers due to its simplicity and high chemical conversion efficiency.

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

1974-01-01T23:59:59.000Z

494

In situ growth of mesoporous NiO nanoplates on a graphene matrix as cathode catalysts for rechargeable lithium–air batteries  

Science Journals Connector (OSTI)

Abstract NiO/graphene nanocomposites are fabricated via a solvothermal method. Scanning and transmission electron microscopy results indicate that the NiO nanoplates (length, ~100 nm) were homogeneously distributed on the graphene sheets. The electrochemical properties of the samples as active cathode catalysts for rechargeable Li–air batteries are evaluated by constant current charge–discharge cycling. The composites exhibit a reversible capacity of 1160 mAh g?1 after 50 cycles at a discharge current density of 50 mA g?1; this reverse capacity is much higher than that of pure NiO nanoplates (30 mAh g?1). Using graphene as a conductive matrix, a homogeneous distribution of NiO nanoplates is accomplished and graphene serves as a framework for loading as produced Li2O2 during the discharge process, resulting in the excellent electrochemical performance of the composites. The mesoporous structure of the NiO nanoplates is suitable for the transfer of O2 and deposition of Li2O2 produced by the electrochemical reaction. NiO/graphene nanocomposites are a candidate material for high-capacity, low-cost, and nontoxic cathode catalysts in rechargeable Li–air batteries.

Danfeng Qiu; Gang Bu; Bin Zhao; Zixia Lin; Lin Pu; Lijia Pan; Yi Shi

2015-01-01T23:59:59.000Z

495