Sample records for nano titania powder

  1. Synthesis and Microstructure Evolution of Nano-Titania Doped Silicon Coatings

    NASA Astrophysics Data System (ADS)

    Moroz, N. A.; Umapathy, H.; Mohanty, P.

    2010-01-01

    The Anatase phase of Titania (TiO2) in nanocrystalline form is a well known photocatalyst. Photocatalysts are commercially used to accelerate photoreactions and increase photovoltaic efficiency such as in solar cells. This study investigates the in-flight synthesis of Titania and its doping into a Silicon matrix resulting in a catalyst-dispersed coating. A liquid precursor of Titanium Isopropoxide and ethanol was coaxially fed into the plasma gun to form Titania nanoparticles, while Silicon powder was externally injected downstream. Coatings of 75-150 μm thick were deposited onto flat coupons. Further, Silicon powder was alloyed with aluminum to promote crystallization and reduce the amorphous phase in the Silicon matrix. Dense coatings containing nano-Titania particles were observed under electron microscope. X-ray diffraction showed that both the Rutile and Anatase phases of the Titania exist. The influence of process parameters and aluminum alloying on the microstructure evolution of the doped coatings is analyzed and presented.

  2. Titania-polymeric powder coatings with nano-topography support enhanced human mesenchymal cell responses.

    PubMed

    Mozumder, Mohammad Sayem; Zhu, Jesse; Perinpanayagam, Hiran

    2012-10-01

    Titanium implant osseointegration is dependent on the cellular response to surface modifications and coatings. Titania-enriched nanocomposite polymeric resin coatings were prepared through the application of advanced ultrafine powder coating technology. Their surfaces were readily modified to create nano-rough (<100 nm) surface nano-topographies that supported human embryonic palatal mesenchymal cell responses. Energy dispersive x-ray spectroscopy confirmed continuous and homogenous coatings with a similar composition and even distribution of titanium. Scanning electron microscopy (SEM) showed complex micro-topographies, and atomic force microscopy revealed intricate nanofeatures and surface roughness. Cell counts, mitochondrial enzyme activity reduction of yellow 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) to dark purple, SEM, and inverted fluorescence microscopy showed a marked increase in cell attachment, spreading, proliferation, and metabolic activity on the nanostructured surfaces. Reverse Transcription- Polymerase Chain Reaction (RT-PCR) analysis showed that type I collagen and Runx2 expression were induced, and Alizarin red staining showed that mineral deposits were abundant in the cell cultures grown on nanosurfaces. This enhancement in human mesenchymal cell attachment, growth, and osteogenesis were attributed to the nanosized surface topographies, roughness, and moderate wetting characteristics of the coatings. Their dimensional similarity to naturally occurring matrix proteins and crystals, coupled with their increased surface area for protein adsorption, may have facilitated the response. Therefore, this application of ultrafine powder coating technology affords highly biocompatible surfaces that can be readily modified to accentuate the cellular response. Copyright © 2012 Wiley Periodicals, Inc.

  3. Biokinetics and effects of titania nano-material after inhalation and i.v. injection

    NASA Astrophysics Data System (ADS)

    Landsiedel, Robert; Fabian, Eric; Ma-Hock, Lan; Wiench, Karin; van Ravenzwaay, Bennard

    2009-05-01

    Within NanoSafe2 we developed a special inhalation model to investigate deposition of inhaled particles in the lung and the further distribution in the body after. Concurrently, the effects of the inhaled materials in the lung were examined. The results for nano-Titania were compared to results from inhalation studies with micron-sized (non-nano) Titania particles and to quartz particles (DQ12, known to be potent lung toxicants). To build a PBPK model for nano-Titania the tissue distribution of the material was also examined following intravenous (i.v.) administration.

  4. Heats of immersion of titania powders in primer solutions

    NASA Technical Reports Server (NTRS)

    Siriwardane, R.; Wightman, J. P.

    1983-01-01

    The oxide layer present on titanium alloys can play an important role in determining the strength and durability of adhesive bonds. Here, three titania powders in different crystalline phases, rutile-R1, anatase-A1, and anatase-A2, are characterized by several techniques. These include microelectrophoresis, X-ray diffractometry, surface area pore volume analysis, X-ray photoelectron spectroscopy, and measurements of the heats of immersion. Of the three powders, R1 has the highest heat of immersion in water, while the interaction between water and A1 powder is low. Experimental data also suggest a specific preferential interaction of polyphenylquinoxaline with anatase.

  5. Minimum ignition energy of nano and micro Ti powder in the presence of inert nano TiO₂ powder.

    PubMed

    Chunmiao, Yuan; Amyotte, Paul R; Hossain, Md Nur; Li, Chang

    2014-06-15

    The inerting effect of nano-sized TiO2 powder on ignition sensitivity of nano and micro Ti powders was investigated with a Mike 3 apparatus. "A little is not good enough" is also suitable for micro Ti powders mixed with nano-sized solid inertants. MIE of the mixtures did not significantly increase until the TiO2 percentage exceeded 50%. Nano-sized TiO2 powders were ineffective as an inertant when mixed with nano Ti powders, especially at higher dust loadings. Even with 90% nano TiO2 powder, mixtures still showed high ignition sensitivity because the statistic energy was as low as 2.1 mJ. Layer fires induced by ignited but unburned metal particles may occur for micro Ti powders mixed with nano TiO2 powders following a low level dust explosion. Such layer fires could lead to a violent dust explosion after a second dispersion. Thus, additional attention is needed to prevent metallic layer fires even where electric spark potential is low. In the case of nano Ti powder, no layer fires were observed because of less flammable material involved in the mixtures investigated, and faster flame propagation in nanoparticle clouds. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Minimum ignition temperature of nano and micro Ti powder clouds in the presence of inert nano TiO2 powder.

    PubMed

    Yuan, Chunmiao; Amyotte, Paul R; Hossain, Md Nur; Li, Chang

    2014-06-30

    Minimum ignition temperature (MIT) of micro Ti powder increased gradually with increases in nano-sized TiO2 employed as an inertant. Solid TiO2 inertant significantly reduced ignition hazard of micro Ti powder in contact with hot surfaces. The MIT of nano Ti powder remained low (583 K), however, even with 90% TiO2. The MIT of micro Ti powder, when mixed with nano Ti powder at concentrations as low as 10%, decreased so dramatically that its application as a solid fuel may be possible. A simple MIT model was proposed for aggregate particle size estimation and better understanding of the inerting effect of nano TiO2 on MIT. Estimated particle size was 1.46-1.51 μm larger than that in the 20-L sphere due to poor dispersion in the BAM oven. Calculated MITs were lower than corresponding empirically determined values for micro Ti powder because nano-sized TiO2 coated the micro Ti powder, thereby decreasing its reaction kinetics. In the case of nano Ti powder, nano-sized TiO2 facilitated dispersion of nano Ti powder which resulted in a calculated MIT that was greater than the experimentally determined value. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Plasma column and nano-powder generation from solid titanium by localized microwaves in air

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Popescu, Simona; Jerby, Eli, E-mail: jerby@eng.tau.ac.il; Meir, Yehuda

    2015-07-14

    This paper studies the effect of a plasma column ejected from solid titanium by localized microwaves in an ambient air atmosphere. Nanoparticles of titanium dioxide (titania) are found to be directly synthesized in this plasma column maintained by the microwave energy in the cavity. The process is initiated by a hotspot induced by localized microwaves, which melts the titanium substrate locally. The molten hotspot emits ionized titanium vapors continuously into the stable plasma column, which may last for more than a minute duration. The characterization of the dusty plasma obtained is performed in-situ by small-angle X-ray scattering (SAXS), optical spectroscopy,more » and microwave reflection analyses. The deposited titania nanoparticles are structurally and morphologically analyzed by ex-situ optical and scanning-electron microscope observations, and also by X-ray diffraction. Using the Boltzmann plot method combined with the SAXS results, the electron temperature and density in the dusty plasma are estimated as ∼0.4 eV and ∼10{sup 19 }m{sup −3}, respectively. The analysis of the plasma product reveals nanoparticles of titania in crystalline phases of anatase, brookite, and rutile. These are spatially arranged in various spherical, cubic, lamellar, and network forms. Several applications are considered for this process of titania nano-powder production.« less

  8. Energy-conscious production of titania and titanium powders from slag

    NASA Astrophysics Data System (ADS)

    Middlemas, Scott C.

    Titanium dioxide (TiO2) is used as a whitening agent in numerous domestic and technological applications and is mainly produced by the high temperature chloride process. A new hydrometallurgical process for making commercially pure TiO2 pigment is described with the goal of reducing the necessary energy consumption and CO2 emissions. The process includes alkaline roasting of titania slag with subsequent washing, HCl leaching, solvent extraction, hydrolysis, and calcination stages. The thermodynamics of the roasting reaction were analyzed, and the experimental parameters for each step in the new process were optimized with respect to TiO 2 recovery, final product purity, and total energy requirements. Contacting the leach solution with a tertiary amine extractant resulted in complete Fe extraction in a single stage and proved effective in reducing the concentration of discoloring impurities in the final pigment to commercially acceptable levels. Additionally, a new method of producing Ti powders from titania slag is proposed as a potentially more energy efficient and lower cost alternative to the traditional Kroll process. Thermodynamic analysis and initial experimental results validate the concept of reducing titanium slag with a metal hydride to produce titanium hydride (TiH2) powders, which are subsequently purified by leaching and dehydrided to form Ti powders. The effects of reducing agent type, heating time and temperature, ball milling, powder compaction, and eutectic chloride salts on the conversion of slag to TiH2 powders were determined. The purification of reduced powders through NH4Cl, NaOH, and HCl leaching stages was investigated, and reagent concentration, leaching temperature, and time were varied in order to determine the best conditions for maximum impurity removal and recovery of TiH2. A model plant producing 100,000 tons TiO2 per year was designed that would employ the new method of pigment manufacture. A comparison of the new process and the

  9. Titania nanotube powders obtained by rapid breakdown anodization in perchloric acid electrolytes

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ali, Saima, E-mail: saima.ali@aalto.fi; Hannula, Simo-Pekka

    Titania nanotube (TNT) powders are prepared by rapid break down anodization (RBA) in a 0.1 M perchloric acid (HClO{sub 4}) solution (Process 1), and ethylene glycol (EG) mixture with HClO{sub 4} and water (Process 2). A study of the as-prepared and calcined TNT powders obtained by both processes is implemented to evaluate and compare the morphology, crystal structure, specific surface area, and the composition of the nanotubes. Longer TNTs are formed in Process 1, while comparatively larger pore diameter and wall thickness are obtained for the nanotubes prepared by Process 2. The TNTs obtained by Process 1 are converted tomore » nanorods at 350 °C, while nanotubes obtained by Process 2 preserve tubular morphology till 350 °C. In addition, the TNTs prepared by an aqueous electrolyte have a crystalline structure, whereas the TNTs obtained by Process 2 are amorphous. Samples calcined till 450 °C have XRD peaks from the anatase phase, while the rutile phase appears at 550 °C for the TNTs prepared by both processes. The Raman spectra also show clear anatase peaks for all samples except the as-prepared sample obtained by Process 2, thus supporting the XRD findings. FTIR spectra reveal the presence of O-H groups in the structure for the TNTs obtained by both processes. However, the presence is less prominent for annealed samples. Additionally, TNTs obtained by Process 2 have a carbonaceous impurity present in the structure attributed to the electrolyte used in that process. While a negligible weight loss is typical for TNTs prepared from aqueous electrolytes, a weight loss of 38.6% in the temperature range of 25–600 °C is found for TNTs prepared in EG electrolyte (Process 2). A large specific surface area of 179.2 m{sup 2} g{sup −1} is obtained for TNTs prepared by Process 1, whereas Process 2 produces nanotubes with a lower specific surface area. The difference appears to correspond to the dimensions of the nanotubes obtained by the two processes. - Graphical

  10. Mesoporous Titania Powders: The Role of Precursors, Ligand Addition and Calcination Rate on Their Morphology, Crystalline Structure and Photocatalytic Activity

    PubMed Central

    Masolo, Elisabetta; Meloni, Manuela; Garroni, Sebastiano; Mulas, Gabriele; Enzo, Stefano; Baró, Maria Dolors; Rossinyol, Emma; Rzeszutek, Agnieszka; Herrmann-Geppert, Iris; Pilo, Maria

    2014-01-01

    We evaluate the influence of the use of different titania precursors, calcination rate, and ligand addition on the morphology, texture and phase content of synthesized mesoporous titania samples, parameters which, in turn, can play a key role in titania photocatalytic performances. The powders, obtained through the evaporation-induced self-assembly method, are characterized by means of ex situ X-Ray Powder Diffraction (XRPD) measurements, N2 physisorption isotherms and transmission electron microscopy. The precursors are selected basing on two different approaches: the acid-base pair, using TiCl4 and Ti(OBu)4, and a more classic route with Ti(OiPr)4 and HCl. For both precursors, different specimens were prepared by resorting to different calcination rates and with and without the addition of acetylacetone, that creates coordinated species with lower hydrolysis rates, and with different calcination rates. Each sample was employed as photoanode and tested in the water splitting reaction by recording I-V curves and comparing the results with commercial P25 powders. The complex data framework suggests that a narrow pore size distribution, due to the use of acetylacetone, plays a major role in the photoactivity, leading to a current density value higher than that of P25. PMID:28344237

  11. Straightforward fabrication of black nano silica dusting powder for latent fingerprint imaging

    NASA Astrophysics Data System (ADS)

    Komalasari, Isna; Krismastuti, Fransiska Sri Herwahyu; Elishian, Christine; Handayani, Eka Mardika; Nugraha, Willy Cahya; Ketrin, Rosi

    2017-11-01

    Imaging of latent fingerprint pattern (aka fingermark) is one of the most important and accurate detection methods in forensic investigation because of the characteristic of individual fingerprint. This detection technique relies on the mechanical adherence of fingerprint powder to the moisture and oily component of the skin left on the surface. The particle size of fingerprint powder is one of the critical parameter to obtain excellent fingerprint image. This study develops a simple, cheap and straightforward method to fabricate Nano size black dusting fingerprint powder based on Nano silica and applies the powder to visualize latent fingerprint. The nanostructured silica was prepared from tetraethoxysilane (TEOS) and then modified with Nano carbon, methylene blue and sodium acetate to color the powder. Finally, as a proof-of-principle, the ability of this black Nano silica dusting powder to image latent fingerprint is successfully demonstrated and the results show that this fingerprint powder provides clearer fingerprint pattern compared to the commercial one highlighting the potential application of the nanostructured silica in forensic science.

  12. Synthesis of sea urchin-like carbon nanotubes on nano-diamond powder.

    PubMed

    Hwang, E J; Lee, S K; Jeong, M G; Lee, Y B; Lim, D S

    2012-07-01

    Carbon nanotubes (CNTs) have unique atomic structure and properties, such as a high aspect ratio and high mechanical, electrical and thermal properties. On the other hand, the agglomeration and entanglement of CNTs restrict their applications. Sea urchin-like multiwalled carbon nanotubes, which have a small aspect ratio, can minimize the problem of dispersion. The high hardness, thermal conductivity and chemical inertness of the nano-diamond powder make it suitable for a wide range of applications in the mechanical and electronic fields. CNTs were synthesized on nano-diamond powder by thermal CVD to fabricate a filler with suitable mechanical properties and chemical stability. This paper reports the growth of CNTs with a sea urchin-like structure on the surface of the nano-diamond powder. Nano-diamond powders were dispersed in an attritional milling system using zirconia beads in ethanol. After the milling process, 3-aminopropyltrimethoxysilane (APS) was added as a linker. Silanization was performed between the nano-diamond particles and the metal catalyst. Iron chloride was used as a catalyst for the fabrication of the CNTs. After drying, catalyst-attached nano-diamond powders could be achieved. The growth of the carbon nanotubes was carried out by CVD. The CNT morphology was examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The mean diameter and length of the CNTs were 201 nm and 3.25 microm, respectively.

  13. Characteristic of nanoparticles generated from different nano-powders by using different dispersion methods

    NASA Astrophysics Data System (ADS)

    Tsai, Chuen-Jinn; Lin, Guan-Yu; Liu, Chun-Nan; He, Chi-En; Chen, Chun-Wan

    2012-03-01

    A standard rotating drum with a modified sampling train (RD), a vortex shaker (VS), and a SSPD (small-scale powder disperser) were used to investigate the emission characteristics of nano-powders, including nano-titanium dioxide (nano-TiO2, primary diameter: 21 nm), nano-zinc oxide (nano-ZnO, primary diameter: 30-50 nm), and nano-silicon dioxide (nano-SiO2, primary diameter: 10-30 nm). A TSI SMPS (scanning mobility particle sizer), a TSI APS (aerodynamic particle sizer), and a MSP MOUDI (micro-orifice uniform deposit impactor) were used to measure the number and mass distributions of generated particles. Significant differences in specific number and mass concentration or distributions were found among different methods and nano-powders with the most specific number and mass concentration and the smallest particles being generated by the most energetic SSPD, followed by VS and RD. Near uni-modal number or mass distributions were observed for the SSPD while bi-modal number or mass distributions existed for nano-powders except nano-SiO2 which also exhibited bimodal mass distributions. The 30-min average results showed that the mass median aerodynamic diameter (MMAD) and number median diameter (NMD) of the SSPD ranged 1.1-2.1 μm and 166-261 nm, respectively, for all three nano-powders, which were smaller than those of the VS (MMAD: 3.3-6.0 μm and NMD: 156-462 nm), and the RD (MMAD: 5.2-11.2 μm and NMD: 198-479 nm). For nano-particles (electric mobility diameter < 100 nm), specific mass concentrations were nearly negligible for all three nano-powders and test methods. Specific number concentrations of nano-particles were low for the RD tester but were elevated when more energetic VS and SSPD testers were used. The quantitative size and concentration data obtained in this study is useful to elucidate the field emission and personal exposure data in the future provided that particle loss in the generation system is carefully assessed.

  14. Slip casting nano-particle powders for making transparent ceramics

    DOEpatents

    Kuntz, Joshua D [Livermore, CA; Soules, Thomas F [Livermore, CA; Landingham, Richard Lee [Livermore, CA; Hollingsworth, Joel P [Oakland, CA

    2011-04-12

    A method of making a transparent ceramic including the steps of providing nano-ceramic powders in a processed or unprocessed form, mixing the powders with de-ionized water, the step of mixing the powders with de-ionized water producing a slurry, sonifing the slurry to completely wet the powder and suspend the powder in the de-ionized water, separating very fine particles from the slurry, molding the slurry, and curing the slurry to produce the transparent ceramic.

  15. Templated synthesis of nanoporous titania/nanocarbon composites

    NASA Astrophysics Data System (ADS)

    Mistry, Jayur

    Hexagonally patterned (honeycomb structured) nano-porous titania finds distinct applications in the field of material science, electronics, and catalysis. The preparation of titania/nanocarbon composites was carried out using titanium iso-propoxide precursor and a viscous surfactant templated system arranged into nanoscopic channels of water and iso-octane. Nanocarbon was introduced into the titania pores, as it was dispersed into the water (used to increase the W0), while making templets. Prepared titania/nanocarbon composites were analyzed under scanning electron microscopy (SEM), transmission electron microscope (TEM), and X-ray diffraction (XRD) after a specific heat treatment. SEM and TEM allows us to see the morphology of the hexagonally patterned templates and XRD shows the change in the crystallinity of the titania after the heat treatment. Further tests are run with the Solartron™ CellTest potentiostat syste, which, allows us to study the electrical properties of the nanocomposites. The composites synthesized have wide applications in number of fields, including energy, sensors and electronics.

  16. Bio-ecological consequences of crop seeds treatment with metal nano-powders

    NASA Astrophysics Data System (ADS)

    Churilov, G.

    2015-11-01

    As a result of our investigations we have determined the optimal concentrations of ferrum, cobalt and cuprum nano-powders recommended to be used as micro-fertilizers increasing the yield and feed value of crops at the expense of accumulating biologically active combinations by 25-35%. In unfavorable climate conditions, for example in a case of excess moisture or heat and drought, the plants development and ripening suffer. Our investigations have shown that the stimulating effect of nano-powders has lowered the effect of stress situations on plants development and simultaneously increased the rape seeds yield and quality. Treating the seeds with the drugs being studied has provided the high crop protection. If consider that the maximum efficiency of protectants Chinuk, SK (20 kg/t of seeds) and Cruiser, KS (10 kg/t of seeds) then for the same effect one needs nano-powders 0.1 g per hectare norm of seeds planting.

  17. Controlled Growth of Ceria Nanoarrays on Anatase Titania Powder: A Bottom-up Physical Picture.

    PubMed

    Kim, Hyun You; Hybertsen, Mark S; Liu, Ping

    2017-01-11

    The leading edge of catalysis research motivates physical understanding of the growth of nanoscale oxide structures on different supporting oxide materials that are themselves also nanostructured. This research opens up for consideration a diverse range of facets on the support material, versus the single facet typically involved in wide-area growth of thin films. Here, we study the growth of ceria nanoarchitectures on practical anatase titania powders as a showcase inspired by recent experiments. Density functional theory (DFT)-based methods are employed to characterize and rationalize the broad array of low energy nanostructures that emerge. Using a bottom-up approach, we are able to identify and characterize the underlying mechanisms for the facet-dependent growth of various ceria motifs on anatase titania based on formation energy. These motifs include 0D clusters, 1D chains, 2D plates, and 3D nanoparticles. The ceria growth mode and morphology are determined by the interplay of several factors including the role of the common cation valence, the interface template effect for different facets of the anatase support, enhanced ionic binding for more compact ceria motifs, and the local structural flexibility of oxygen ions in bridging the interface between anatase and ceria structures.

  18. Controlled Growth of Ceria Nanoarrays on Anatase Titania Powder: A Bottom-up Physical Picture

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kim, Hyun You; Hybertsen, Mark S.; Liu, Ping

    The leading edge of catalysis research motivates physical understanding of the growth of nanoscale oxide structures on different supporting oxide materials that are themselves also nanostructured. This research opens up for consideration a diverse range of facets on the support material, versus the single facet typically involved in wide-area growth of thin films. In this paper, we study the growth of ceria nanoarchitectures on practical anatase titania powders as a showcase inspired by recent experiments. Density functional theory (DFT)-based methods are employed to characterize and rationalize the broad array of low energy nanostructures that emerge. Using a bottom-up approach, wemore » are able to identify and characterize the underlying mechanisms for the facet-dependent growth of various ceria motifs on anatase titania based on formation energy. These motifs include 0D clusters, 1D chains, 2D plates, and 3D nanoparticles. Finally, the ceria growth mode and morphology are determined by the interplay of several factors including the role of the common cation valence, the interface template effect for different facets of the anatase support, enhanced ionic binding for more compact ceria motifs, and the local structural flexibility of oxygen ions in bridging the interface between anatase and ceria structures.« less

  19. Controlled Growth of Ceria Nanoarrays on Anatase Titania Powder: A Bottom-up Physical Picture

    DOE PAGES

    Kim, Hyun You; Hybertsen, Mark S.; Liu, Ping

    2016-12-05

    The leading edge of catalysis research motivates physical understanding of the growth of nanoscale oxide structures on different supporting oxide materials that are themselves also nanostructured. This research opens up for consideration a diverse range of facets on the support material, versus the single facet typically involved in wide-area growth of thin films. In this paper, we study the growth of ceria nanoarchitectures on practical anatase titania powders as a showcase inspired by recent experiments. Density functional theory (DFT)-based methods are employed to characterize and rationalize the broad array of low energy nanostructures that emerge. Using a bottom-up approach, wemore » are able to identify and characterize the underlying mechanisms for the facet-dependent growth of various ceria motifs on anatase titania based on formation energy. These motifs include 0D clusters, 1D chains, 2D plates, and 3D nanoparticles. Finally, the ceria growth mode and morphology are determined by the interplay of several factors including the role of the common cation valence, the interface template effect for different facets of the anatase support, enhanced ionic binding for more compact ceria motifs, and the local structural flexibility of oxygen ions in bridging the interface between anatase and ceria structures.« less

  20. Nano titania aided clustering and adhesion of beneficial bacteria to plant roots to enhance crop growth and stress management.

    PubMed

    Palmqvist, N G M; Bejai, S; Meijer, J; Seisenbaeva, G A; Kessler, V G

    2015-05-13

    A novel use of Titania nanoparticles as agents in the nano interface interaction between a beneficial plant growth promoting bacterium (Bacillus amyloliquefaciens UCMB5113) and oilseed rape plants (Brassica napus) for protection against the fungal pathogen Alternaria brassicae is presented. Two different TiO2 nanoparticle material were produced by the Sol-Gel approach, one using the patented Captigel method and the other one applying TiBALDH precursor. The particles were characterized by transmission electron microscopy, thermogravimetric analysis, X-ray diffraction, dynamic light scattering and nano particle tracking analysis. Scanning electron microscopy showed that the bacterium was living in clusters on the roots and the combined energy-dispersive X-ray spectroscopy analysis revealed that titanium was present in these cluster formations. Confocal laser scanning microscopy further demonstrated an increased bacterial colonization of Arabidopsis thaliana roots and a semi-quantitative microscopic assay confirmed an increased bacterial adhesion to the roots. An increased amount of adhered bacteria was further confirmed by quantitative fluorescence measurements. The degree of infection by the fungus was measured and quantified by real-time-qPCR. Results showed that Titania nanoparticles increased adhesion of beneficial bacteria on to the roots of oilseed rape and protected the plants against infection.

  1. Nano titania aided clustering and adhesion of beneficial bacteria to plant roots to enhance crop growth and stress management

    NASA Astrophysics Data System (ADS)

    Palmqvist, N. G. M.; Bejai, S.; Meijer, J.; Seisenbaeva, G. A.; Kessler, V. G.

    2015-05-01

    A novel use of Titania nanoparticles as agents in the nano interface interaction between a beneficial plant growth promoting bacterium (Bacillus amyloliquefaciens UCMB5113) and oilseed rape plants (Brassica napus) for protection against the fungal pathogen Alternaria brassicae is presented. Two different TiO2 nanoparticle material were produced by the Sol-Gel approach, one using the patented Captigel method and the other one applying TiBALDH precursor. The particles were characterized by transmission electron microscopy, thermogravimetric analysis, X-ray diffraction, dynamic light scattering and nano particle tracking analysis. Scanning electron microscopy showed that the bacterium was living in clusters on the roots and the combined energy-dispersive X-ray spectroscopy analysis revealed that titanium was present in these cluster formations. Confocal laser scanning microscopy further demonstrated an increased bacterial colonization of Arabidopsis thaliana roots and a semi-quantitative microscopic assay confirmed an increased bacterial adhesion to the roots. An increased amount of adhered bacteria was further confirmed by quantitative fluorescence measurements. The degree of infection by the fungus was measured and quantified by real-time-qPCR. Results showed that Titania nanoparticles increased adhesion of beneficial bacteria on to the roots of oilseed rape and protected the plants against infection.

  2. Nano titania aided clustering and adhesion of beneficial bacteria to plant roots to enhance crop growth and stress management

    PubMed Central

    Palmqvist, N. G. M.; Bejai, S.; Meijer, J.; Seisenbaeva, G. A.; Kessler, V. G.

    2015-01-01

    A novel use of Titania nanoparticles as agents in the nano interface interaction between a beneficial plant growth promoting bacterium (Bacillus amyloliquefaciens UCMB5113) and oilseed rape plants (Brassica napus) for protection against the fungal pathogen Alternaria brassicae is presented. Two different TiO2 nanoparticle material were produced by the Sol-Gel approach, one using the patented Captigel method and the other one applying TiBALDH precursor. The particles were characterized by transmission electron microscopy, thermogravimetric analysis, X-ray diffraction, dynamic light scattering and nano particle tracking analysis. Scanning electron microscopy showed that the bacterium was living in clusters on the roots and the combined energy-dispersive X-ray spectroscopy analysis revealed that titanium was present in these cluster formations. Confocal laser scanning microscopy further demonstrated an increased bacterial colonization of Arabidopsis thaliana roots and a semi-quantitative microscopic assay confirmed an increased bacterial adhesion to the roots. An increased amount of adhered bacteria was further confirmed by quantitative fluorescence measurements. The degree of infection by the fungus was measured and quantified by real-time-qPCR. Results showed that Titania nanoparticles increased adhesion of beneficial bacteria on to the roots of oilseed rape and protected the plants against infection. PMID:25970693

  3. Nano-Titania Photocatalyst Loaded on W-MCM-41 Support and Its Highly Efficient Degradation of Methylene Blue

    NASA Astrophysics Data System (ADS)

    Shankar, H.; Saravanan, R.; Narayanan, V.; Stephen, A.

    2011-07-01

    Most of the azo dyes produced in textile, printing, paper manufacturing, pulp processing and pharmaceutical industries contain different organic contaminants. These dyes can enter the body through ingestion and the high content in living systems can prove to be carcinogenic. Therefore photocatalytic degradation of such toxic organic compounds in water, in the presence of semiconductor powders has received much attention over the last two decades. Nanocrystalline titanium dioxide, TiO2, is a well studied and commonly used material for photocatalytic applications. However, the control of particle size, monodispersity, large catalytic surface for sufficient adsorption of organic pollutants, recovery and recycle of TiO2 nanoparticles are challenging tasks. Hence in the present study, titania was introduced into the nanopores (2-10 nm size) of MCM-41 to produce stable nanoparticles of uniform size and shape. Further, in order to lengthen the life time of the excited electrons/holes during photoreaction, tungsten atoms were incorporated in to the MCM-41 silica matrix in addition to titania loading.

  4. Acoustic Properties of Polyurethane Composition Reinforced with Carbon Nanotubes and Silicon Oxide Nano-powder

    NASA Astrophysics Data System (ADS)

    Orfali, Wasim A.

    This article demonstrates the acoustic properties of added small amount of carbon-nanotube and siliconoxide nano powder (S-type, P-Type) to the host material polyurethane composition. By adding CNT and/or nano-silica in the form of powder at different concentrations up to 2% within the PU composition to improve the sound absorption were investigated in the frequency range up to 1600 Hz. Sound transmission loss measurement of the samples were determined using large impedance tube. The tests showed that addition of 0.2 wt.% Silicon Oxide Nano-powder and 0.35 wt.% carbon nanotube to polyurethane composition improved sound transmissions loss (Sound Absorption) up to 80 dB than that of pure polyurethane foam sample.

  5. Effect of drying environment on grain size of titanium dioxide nano-powder synthesized via sol-gel method

    NASA Astrophysics Data System (ADS)

    Zandi, Pegah; Hosseini, Elham; Rashchi, Fereshteh

    2018-01-01

    Titanium dioxide Nano powder has been synthesized from titanium isopropoxide (TTIP) in chloride media by sol-gel method. In this research, the effect of the drying environment, from air to oven drying at 100 °C, calcination time and temperature on nano TiO2 grain size was investigated. The synthesized powder was analyzed by x-ray diffraction and scanning electron microscope. Based on the results, the powder has been crystallized in anatase and rutile phases, due to different calcination temperatures. At temperatures above 600 °C, the Titanium dioxide nano powder has been crystallized as rutile. The crystalline structure of titanium dioxide nano powder changed because of the different calcination temperatures and time applied. The average particle size of the powder dried in air was larger than the powder dried in oven. The minimum particle size of the powder dried in air was 50 nm and in the oven was 9 nm, observed and calculated Williamson-Hall equation. All in all, with overall increasing of calcination time and temperature the grain size increased. Moreover, in the case of temperature, after a certain temperature, the grain size became constant and didn't change significantly.

  6. Hydroxyapatite formation on titania-based materials in a solution mimicking body fluid: Effects of manganese and iron addition in anatase.

    PubMed

    Shin, Euisup; Kim, Ill Yong; Cho, Sung Baek; Ohtsuki, Chikara

    2015-03-01

    Hydroxyapatite formation on the surfaces of implanted materials plays an important role in osteoconduction of bone substitutes in bone tissues. Titania hydrogels are known to instigate hydroxyapatite formation in a solution mimicking human blood plasma. To date, the relationship between the surface characteristics of titania and hydroxyapatite formation on its surface remains unclear. In this study, titania powders with varying surface characteristics were prepared by addition of manganese or iron to examine hydroxyapatite formation in a type of simulated body fluid (Kokubo solution). Hydroxyapatite formation was monitored by observation of deposited particles with scale-like morphology on the prepared titania powders. The effect of the titania surface characteristics, i.e., crystal structure, zeta potential, hydroxy group content, and specific surface area, on hydroxyapatite formation was examined. Hydroxyapatite formation was observed on the surface of titania powders that were primarily anatase, and featured a negative zeta potential and low specific surface areas irrespective of the hydroxy group content. High specific surface areas inhibited the formation of hydroxyapatite because calcium and phosphate ions were mostly consumed by adsorption on the titania surface. Thus, these surface characteristics of titania determine its osteoconductivity following exposure to body fluid. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Development and characterization of silica and titania based nano structured materials for the removal of indoor and outdoor air pollutants

    NASA Astrophysics Data System (ADS)

    Peiris, Thelge Manindu Nirasha

    Solar energy driven catalytic systems have gained popularity in environmental remediation recently. Various photocatalytic systems have been reported in this regard and most of the photocatalysts are based on well-known semiconducting material, Titanium Dioxide, while some are based on other materials such as Silicon Dioxide and various Zeolites. However, in titania based photocatalysts, titania is actively involved in the catalytic mechanism by absorbing light and generating exitons. Because of this vast popularity of titania in the field of photocatalysis it is believed that photocatalysis mainly occurs via non-localized mechanisms and semiconductors are extremely important. Even though it is still rare, photocatalysis could be localized and possible without use of a semiconductor as well. Thus, to support localized photocatalytic systems, and to compare the activity to titania based systems, degradation of organic air pollutants by nanostructured silica, titania and mixed silica titania systems were studied. New materials were prepared using two different approaches, precipitation technique (xerogel) and aerogel preparation technique. The prepared xerogel samples were doped with both metal (silver) and non-metals (carbon and sulfur) and aerogel samples were loaded with Chromium, Cobalt and Vanadium separately, in order to achieve visible light photocatalytic activity. Characterization studies of the materials were carried out using Nova BET analysis, DR UV-vis spectrometry, powder X-ray diffraction, X-ray photoelectron Spectroscopy, FT-IR spectroscopy, Transmission Electron Microscopy, etc. Kinetics of the catalytic activities was studied using a Shimadzu GCMS-QP 5000 instrument using a closed glass reactor. All the experiments were carried out in gaseous phase using acetaldehyde as the model pollutant. Kinetic results suggest that chromium doped silica systems are good UV and visible light active photocatalysts. This is a good example for a localized

  8. Nano powders, components and coatings by plasma technique

    DOEpatents

    McKechnie, Timothy N [Brownsboro, AL; Antony, Leo V. M. [Huntsville, AL; O'Dell, Scott [Arab, AL; Power, Chris [Guntersville, AL; Tabor, Terry [Huntsville, AL

    2009-11-10

    Ultra fine and nanometer powders and a method of producing same are provided, preferably refractory metal and ceramic nanopowders. When certain precursors are injected into the plasma flame in a reactor chamber, the materials are heated, melted and vaporized and the chemical reaction is induced in the vapor phase. The vapor phase is quenched rapidly to solid phase to yield the ultra pure, ultra fine and nano product. With this technique, powders have been made 20 nanometers in size in a system capable of a bulk production rate of more than 10 lbs/hr. The process is particularly applicable to tungsten, molybdenum, rhenium, tungsten carbide, molybdenum carbide and other related materials.

  9. Nano powders, components and coatings by plasma technique

    NASA Technical Reports Server (NTRS)

    McKechnie, Timothy N. (Inventor); Antony, Leo V. M. (Inventor); O'Dell, Scott (Inventor); Power, Chris (Inventor); Tabor, Terry (Inventor)

    2009-01-01

    Ultra fine and nanometer powders and a method of producing same are provided, preferably refractory metal and ceramic nanopowders. When certain precursors are injected into the plasma flame in a reactor chamber, the materials are heated, melted and vaporized and the chemical reaction is induced in the vapor phase. The vapor phase is quenched rapidly to solid phase to yield the ultra pure, ultra fine and nano product. With this technique, powders have been made 20 nanometers in size in a system capable of a bulk production rate of more than 10 lbs/hr. The process is particularly applicable to tungsten, molybdenum, rhenium, tungsten carbide, molybdenum carbide and other related materials.

  10. Defect Control of the WC Hardmetal by Mixing Recycled WC Nano Powder and Tungsten Powder

    NASA Astrophysics Data System (ADS)

    Hur, Man Gyu; Shin, Mi Kyung; Kim, Deug Joong; Yoon, Dae Ho

    2018-03-01

    Tungsten metal powder was added to recycled WC nano powder to control the macro and micro defects of WC hardmetal. The macro and micro defects caused by the excess carbon in the recycled WC powder were markedly removed after the addition of tungsten metal powder ranging from 2 to 6 wt%. The density and hardness of the WC hardmetals also increased due to the removal of defects after adding the tungsten metal powder. The density and hardness of WC hardmetals with the addition of W metal powder ranged from 8 to 12 wt% increased linearly as the W metal powder content increased due to the formation of a new (Co- and W-rich WC) composition. The surface morphology of the WC hardmetals was observed via field emission scanning electron microscopy, and a quantitative elemental analysis was conducted via X-ray fluorescence spectrometry and energy dispersive X-ray analysis. The density and hardness of the WC hardmetals were respectively measured using an analytical balance and a Vikers hardness tester. The effect on the defects in the recycled WC hardmetals through the addition of the tungsten metal powder was discussed in detail.

  11. Characteristics of nano-sized yttria powder synthesized by a polyvinyl alcohol solution route at low temperature.

    PubMed

    Lee, Sang-Jin; Jung, Choong-Hwan

    2012-01-01

    Nano-sized yttria (Y2O3) powders were successfully synthesized at a low temperature of 400 degrees C by a simple polymer solution route. PVA polymer, as an organic carrier, contributed to an atom-scale homogeneous precursor gel and it resulted in fully crystallized, nano-sized yttria powder with high specific surface area through the low temperature calcination. In this process, the content of PVA, calcination temperature and heating time affected the microstructure and crystallization behavior of the powders. The development of crystalline phase and the final particle size were strongly dependant on the oxidation reaction from the polymer burn-out step and the PVA content. In this paper, the PVA solution technique for the fabrication of nano-sized yttria powders is introduced. The effects of PVA content and holding time on the powder morphology and powder specific surface area are also studied. The characterization of the synthesized powders is examined by using XRD, DTA/TG, SEM, TEM and nitrogen gas adsorption. The yttria powder synthesized from the PVA content of 3:1 ratio and calcined at 400 degrees C had a crystallite size of about 20 nm or less with a high surface areas of 93.95-120.76 m2 g(-1).

  12. Preparation of ZrO II/nano-TiO II composite powder by sol-gel method

    NASA Astrophysics Data System (ADS)

    Baharvandi, H. R.; Mohammadi, E.; Abdizadeh, H.; Hadian, A. M.; Ehsani, N.

    2007-07-01

    The effects of concentration of TTIP, amount of distilled water, and calcination temperature on morphology and particle size distribution of ZrO II/nano-TiO II catalysts were investigated. Mixed ZrO II/nano-TiO II powders were prepared by a modified sol-gel method by varying the mole fraction of TTIP from 0.002 to 0.01, H IIO/TTIP fraction from 2 to 8, and various stirring time (2, 4, and 10 h). The prepared ZrO II/nano-TiO II powders have been characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and TG/DTA. Each oxide was calcined at the temperature between 110 and 1000°C. The results showed that the calcinations temperature has a pronounced effect on the phase formation and particle size of the calcined zirconium titanate (ZT) powders.

  13. Adsorption of vitamin E on mesoporous titania nanocrystals

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Shih, C.J., E-mail: cjshih@kmu.edu.tw; Lin, C.T.; Wu, S.M.

    2010-07-15

    Tri-block nonionic surfactant and titanium chloride were used as starting materials for the synthesis of mesoporous titania nanocrystallite powders. The main objective of the present study was to examine the synthesis of mesoporous titania nanocrystals and the adsorption of vitamin E on those nanocrystals using X-ray diffraction (XRD), transmission electron microscopy, and nitrogen adsorption and desorption isotherms. When the calcination temperature was increased to 300 {sup o}C, the reflection peaks in the XRD pattern indicated the presence of an anatase phase. The crystallinity of the nanocrystallites increased from 80% to 98.6% with increasing calcination temperature from 465 {sup o}C tomore » 500 {sup o}C. The N{sub 2} adsorption data and XRD data taken after vitamin E adsorption revealed that the vitamin E molecules were adsorbed in the mesopores of the titania nanocrystals.« less

  14. Synthesis of highly-monodisperse spherical titania particles with diameters in the submicron range.

    PubMed

    Tanaka, Shunsuke; Nogami, Daisuke; Tsuda, Natsuki; Miyake, Yoshikazu

    2009-06-15

    Monodisperse titania spheres with particle diameters in the range 380-960 nm were successfully synthesized by hydrolysis and condensation of titanium tetraisopropoxide. The preparation was performed using ammonia or dodecylamine (DDA) as a catalyst in methanol/acetonitrile co-solvent at room temperature. The samples were characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, dynamic light scattering, and nitrogen sorption measurement. The use of DDA was effective for the synthesis of monodisperse titania spheres with low coefficient of variation. When the titania spherical particles with coefficient of variation less than 4% were obtained, the colloidal crystallization easily occurred simply by centrifugation. The monodispersity was maintained even after crystallization of the particles by high temperature annealing. The titania particles prepared using DDA had mesopores near the surface of the spheres, providing high pore accessibility to the sphere from the surface-air interface. The particle size uniformity and photocatalytic reactivity of the titania prepared using DDA were higher than those of the titania prepared using ammonia.

  15. Internal Nano Voids in Yttria-Stabilised Zirconia (YSZ) Powder

    PubMed Central

    Barad, Chen; Shekel, Gal; Shandalov, Michael; Hayun, Hagay; Kimmel, Giora; Shamir, Dror; Gelbstein, Yaniv

    2017-01-01

    Porous yttria-stabilised zirconia ceramics have been gaining popularity throughout the years in various fields, such as energy, environment, medicine, etc. Although yttria-stabilised zirconia is a well-studied material, voided yttria-stabilised zirconia powder particles have not been demonstrated yet, and might play an important role in future technology developments. A sol-gel synthesis accompanied by a freeze-drying process is currently being proposed as a method of obtaining sponge-like nano morphology of embedded faceted voids inside yttria-stabilised zirconia particles. The results rely on a freeze-drying stage as an effective and simple method for generating nano-voided yttria-stabilised zirconia particles without the use of template-assisted additives. PMID:29258227

  16. Internal Nano Voids in Yttria-Stabilised Zirconia (YSZ) Powder.

    PubMed

    Barad, Chen; Shekel, Gal; Shandalov, Michael; Hayun, Hagay; Kimmel, Giora; Shamir, Dror; Gelbstein, Yaniv

    2017-12-18

    Porous yttria-stabilised zirconia ceramics have been gaining popularity throughout the years in various fields, such as energy, environment, medicine, etc. Although yttria-stabilised zirconia is a well-studied material, voided yttria-stabilised zirconia powder particles have not been demonstrated yet, and might play an important role in future technology developments. A sol-gel synthesis accompanied by a freeze-drying process is currently being proposed as a method of obtaining sponge-like nano morphology of embedded faceted voids inside yttria-stabilised zirconia particles. The results rely on a freeze-drying stage as an effective and simple method for generating nano-voided yttria-stabilised zirconia particles without the use of template-assisted additives.

  17. Preparation of hydroxyapatite-titania hybrid coatings on titanium alloy.

    PubMed

    Un, Serhat; Durucan, Caner

    2009-08-01

    Hydroxypapatite-titania hybrid films on Ti6Al4V alloys were prepared by sol-gel technique by incorporating presynthesized hydroxypapatite (Ca(10)(PO(4))(6)(OH)(2) or HAp) powders into a titanium-alkoxide dip coating solution. Titania network was formed by the hydrolysis and condensation of Ti-isopropoxide Ti[OCH(CH(3))(2)](4)-based sols. The effect of titania sol formulation, specifically the effect of organic solvents on the microstructure of the dip coated films calcined at 500 degrees C has been investigated. The coatings exhibit higher tendency for cracking when a high vapor pressure solvent, such as ethanol (C(2)H(5)OH) is used causing development of higher macroscopic stresses during evaporation of the sol. Titania sol formulations replacing the solvent with n-proponal (CH(3)(CH(2))(2)OH) and acetly-acetone (C(5)H(8)O) combinations enhanced the microstructural integrity of the coating during evaporation and calcination treatments. Sol-gel processing parameters, such as multilayer coating application and withdrawal rate, can be employed to change the titania thickness in the range of 0.120-1.1 microm and to control the microstructure of HAp-titania hybrid coatings. A high-calcination temperature in the range of 400-600 degrees C does not cause a distinct change in crystals nature of the titania matrix or HAp, but results in more cracking due to the combined effect of densification originated stresses and thermal stresses upon cooling. Slower withdraw rates and multilayer dip coating lead to coatings more vulnerable to microcracking.

  18. Control of exposure to hexavalent chromium concentration in shielded metal arc welding fumes by nano-coating of electrodes.

    PubMed

    Sivapirakasam, S P; Mohan, Sreejith; Santhosh Kumar, M C; Thomas Paul, Ashley; Surianarayanan, M

    2017-04-01

    Background Cr(VI) is a suspected human carcinogen formed as a by-product of stainless steel welding. Nano-alumina and nano-titania coating of electrodes reduced the welding fume levels. Objective To investigate the effect of nano-coating of welding electrodes on Cr(VI) formation rate (Cr(VI) FR) from a shielded metal arc welding process. Methods The core welding wires were coated with nano-alumina and nano-titania using the sol-gel dip coating technique. Bead-on plate welds were deposited on SS 316 LN plates kept inside a fume test chamber. Cr(VI) analysis was done using an atomic absorption spectrometer (AAS). Results A reduction of 40% and 76%, respectively, in the Cr(VI) FR was observed from nano-alumina and nano-titania coated electrodes. Increase in the fume level decreased the Cr(VI) FR. Discussion Increase in fume levels blocked the UV radiation responsible for the formation of ozone thereby preventing the formation of Cr(VI).

  19. Bioinspired Hierarchical Nanofibrous Silver-Nanoparticle/Anatase-Rutile-Titania Composite as an Anode Material for Lithium-Ion Batteries.

    PubMed

    Luo, Yan; Li, Jiao; Huang, Jianguo

    2016-11-29

    A new bioinspired hierarchical nanofibrous silver-nanoparticle/anatase-rutile-titania (Ag-NP/A-R-titania) composite was fabricated by employing a natural cellulose substance (e.g., commercial laboratory cellulose filter paper) as the structural scaffold template, which was composed of anatase-phase titania (A-titania) nanotubes with rutile-phase titania (R-titania) nanoneedles grown on the surfaces and further silver nanoparticles (AgNPs) immobilized thereon. As it was employed as an anode material for lithium-ion batteries (LIBs), high reversible capacity, enhanced rate performance, and excellent cycling stability were achieved as compared with those of the corresponding cellulose-substance-derived nanotubular A-titania, R-titania, heterogeneous anatase/rutile titania (A-R-titania) composite, and commercial P25 powder. This benefited from its unique porous cross-linked three-dimensional structure inherited from the initial cellulose substance scaffold, which enhances the sufficient electrode/electrolyte contact, relieves the severe volume change upon cycling, and improves the amount of lithium-ion storage; moreover, the high loading content of the silver component in the composite improves the electrical conductivity of the electrode. The structural integrity of the composite was maintained upon long-term charge/discharge cycling, indicating its significant stability.

  20. The use of nano-sized eggshell powder for calcium fortification of cow?s and buffalo?s milk yogurts.

    PubMed

    El-Shibiny, Safinaze; El-Gawad, Mona Abd El-Kader Mohamed Abd; Assem, Fayza Mohamed; El-Sayed, Samah Mosbah

    2018-01-01

    Calcium is an essential element for the growth, activity, and maintenance of the human body. Eggshells are a waste product which has received growing interest as a cheap and effective source of dietary calcium. Yogurt is a food which can be fortified with functional additives, including calcium. The aim of this study was to produce yogurt with a high calcium content by fortification with nano-sized eggshell powder (nano-ESP). Nano-sized ESP was prepared from pre-boiled and dried eggshell, using a ball mill. Yogurt was prepared from cow’s milk supplemented with 3% skimmed milk powder, and from buffalo’s milk fortified with 0.1, 0.2 and 0.3% and 0.1, 0.3 and 0.5% nano-ESP respectively. Electron microscopic transmission showed that the powder consisted of nano-sized crystalline struc- tures (~10 nm). Laser scattering showed that particles followed a normal distribution pattern with z-average of 590.5 nm, and had negative zeta-potential of –9.33 ±4.2 mV. Results regarding changes in yogurt composi- tion, acid development, calcium distribution, biochemical changes, textural parameters and sensory attributes have been presented and discussed. The addition of up to 0.3% nano-ESP made cow and buffalo high-calcium yogurts with an acceptable composition and quality. High-calcium yogurt may offer better health benefits, such as combating osteoporosis.

  1. Experimental investigation of amount of nano-Al2O3 on mechanical properties of Al-based nano-composites fabricated by powder metallurgy (PM)

    NASA Astrophysics Data System (ADS)

    Razzaqi, A.; Liaghat, Gh.; Razmkhah, O.

    2017-10-01

    In this paper, mechanical properties of Aluminum (Al) matrix nano-composites, fabricated by Powder Metallurgy (PM) method, has been investigated. Alumina (Al2O3) nano particles were added in amounts of 0, 2.5, 5, 7.5 and 10 weight percentages (wt%). For this purpose, Al powder (particle size: 20 µm) and nano-Al2O3 (particle size: 20 nm) in various weight percentages were mixed and milled in a blade mixer for 15 minutes in 1500 rpm. Then, the obtained mixture, compacted by means of a two piece die and uniaxial cold press of about 600 MPa and cold iso-static press (CIP), required for different tests. After that, the samples sintered in 600°C for 90 minutes. Compression and three-point bending tests performed on samples and the results, led us to obtain the optimized particle size for achieving best mechanical properties.

  2. Chirality of Single-Handed Twisted Titania Tubular Nanoribbons Prepared Through Sol-gel Transcription.

    PubMed

    Wang, Sibing; Zhang, Chuanyong; Li, Yi; Li, Baozong; Yang, Yonggang

    2015-08-01

    Single-handed twisted titania tubular nanoribbons were prepared through sol-gel transcription using a pair of enantiomers. Handedness was controlled by that of the template. The obtained samples were characterized using field-emission electron microscopy, transmission electron microscopy, diffuse reflectance circular dichroism (DRCD), and X-ray diffraction. The DRCD spectra indicated that the titania nanotubes exhibit optical activity. Although the tubular structure was destroyed after being calcined at 700 °C for 2.0 h, DRCD signals were still identified. However, the DRCD signals disappeared after being calcined at 1000 °C for 2.0 h. The optical activity of titania was proposed to be due to chiral defects. Previous results showed that straight titania tubes could be used as asymmetric autocatalysts, indicating that titania exhibit chirality at the angstrom level. Herein, it was found that they also exhibit DRCD signals, indicating that there are no obvious relationships between morphology at the nano level and chirality at the angstrom level. The nanotube chirality should originate from the chiral defects on the nanotube inner surface. The Fourier transform infrared spectra indicated that the chirality of the titania was transferred from the gelators through the hydrogen bonding between N-H and Ti-OH. © 2015 Wiley Periodicals, Inc.

  3. Plasma-Sprayed Titania and Alumina Coatings Obtained from Feedstocks Prepared by Heterocoagulation with 1 wt.% Carbon Nanotube

    NASA Astrophysics Data System (ADS)

    Jambagi, Sudhakar C.; Agarwal, Anish; Sarkar, Nilmoni; Bandyopadhyay, P. P.

    2018-05-01

    Properties of plasma-sprayed ceramic coatings can be improved significantly by reinforcing such coatings with carbon nanotube (CNT). However, it is difficult to disperse CNT in the plasma spray feedstock owing to its tendency to form agglomerate. A colloidal processing technique, namely heterocoagulation, is effective in bringing about unbundling of CNT, followed by its homogeneous dispersion in the ceramic powder. This report deals with the mixing of micro-sized crushed titania and agglomerated alumina powders with CNT using the heterocoagulation technique. Heterocoagulation of titania was attempted with both cationic and anionic surfactants, and the latter was found to be more effective. Mixing of the oxides and carbon nanotube was also accomplished in a ball mill either in a dry condition or in alcohol, and powders thus obtained were compared with the heterocoagulated powder. The heterocoagulated powder has shown a more homogeneous dispersion of CNT in the oxide. The coatings produced from the heterocoagulated powder demonstrated improvement in hardness, porosity, indentation fracture toughness and elastic modulus. This is attributed to CNT reinforcement.

  4. Indium doped ZnO nano-powders prepared by RF thermal plasma treatment of In2O3 and ZnO

    NASA Astrophysics Data System (ADS)

    Lee, Mi-Yeon; Song, Min-Kyung; Seo, Jun-Ho; Kim, Min-Ho

    2015-06-01

    Indium doped ZnO nano-powders were synthesized by the RF thermal plasma treatment of In2O3 and ZnO. For this purpose, micron-sized ZnO powder was mixed with In2O3 powder at the In/Zn ratios of 0.0, 1.2, and 2.4 at. % by ball milling for 1 h, after which the mixtures were injected into RF thermal plasma generated at the plate power level of ˜140 kV A. As observed from the field emission scanning electron microscopy (FE-SEM) images of the RF plasma-treated powders, hexagonal prism-shaped nano-crystals were mainly obtained along with multi-pod type nano-particles, where the number of multi-pods decreased with increasing In/Zn ratios. In addition, the X-ray diffraction (XRD) data for the as-treated nano-powders showed the diffraction peaks for the In2O3 present in the precursor mixture to disappear, while the crystalline peaks for the single phase of ZnO structure shifted toward lower Bragg angles. In the UV-vis absorption spectra of the as-treated powders, redshifts were also observed with increases of the In/Zn ratios. Together with the FE-SEM images and the XRD data, the redshifts were indicative of the doping process of ZnO with indium, which took place during the RF thermal plasma treatment of In2O3 and ZnO.

  5. Structural and Morphological Evaluation of Nano-Sized MoSi2 Powder Produced by Mechanical Milling

    NASA Astrophysics Data System (ADS)

    Sameezadeh, Mahmood; Farhangi, Hassan; Emamy, Masoud

    Nano-sized intermetallic powders have received great attention owing to their property advantages over conventional micro-sized counterparts. In the present study nano-sized MoSi2 powder has been produced successfully from commercially available MoSi2 (3 μm) by a mechanical milling process carried out for a period of 100 hours. The effects of milling time on size and morphology of the powders were studied by SEM and TEM and image analyzing system. The results indicate that the as-received micrometric powder with a wide size distribution of irregular shaped morphology changes to a narrow size distribution of nearly equiaxed particles with the progress of attrition milling up to 100 h, reaching an average particle size of 71 nm. Structural evolution of milled samples was characterized by XRD to determine the crystallite size and lattice microstrain using Williamson-Hall method. According to the results, the crystallite size of the powders decreases continuously down to 23 nm with increasing milling time up to 100 h and this size refinement is more rapid at the early stages of the milling process. On the other hand, the lattice strain increases considerably with milling up to 65 h and further milling causes no significant changes of lattice strain.

  6. Nano-sized ZnO powders prepared by co-precipitation method with various pH

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Purwaningsih, S. Y., E-mail: sriyanisaputri@gmail.com; Pratapa, S.; Triwikantoro,

    2016-04-19

    In this work, nano-sized ZnO powders have been synthesized by the co-precipitation method with Zn(CH3COOH)2.2H2O, HCl, and NH3.H2O as raw materials in various pH ranging from 8 to 10. The purity, microstructure, chemical group analysis, morphology of the prepared ZnO powders were studied by X-ray diffraction (XRD), Fourier transform infrared spectrometer (FTIR), energy dispersive X-ray spectrometry (EDX), and scanning electron microscope (SEM), respectively. Rietveld refinement of XRD data showed that ZnO crystallizes in the wurtzite structure with high purity. The obtained powders were nano-sized particles with the average crystallite size about 17.9 ± 2.1 nm synthesized with pH of 9.5, atmore » 85°C, and stirring time of 6 h. The SEM results have visualied the morphology of ZnO nanoparticles with spherical-like shape. The effect of processing conditions on morphology of ZnO was also discussed.« less

  7. Fabrication of a pure TiO2 thin film using a self-polymeric titania nano-sol and its properties.

    PubMed

    Park, Won-Kyu; Song, Jeong-Hwan; Kim, Soo-Ryong; Kim, Tae-Hyun; Iwasaki, Mitusnobo

    2012-02-01

    A pure TiO2 thin film without adding any organic binder was fabricated by using a self-polymeric titania nano-sol (14 mass%), which was prepared by the acid peptization method. The particle size distribution in the 14 mass% TiO2 sol, in which almost of particles had a size below 10.2 nm and the crystal phase confirmed by X-ray diffraction analysis was anatase. The diluted nano-sol had a capability to form a thin film at a low temperature (100-400 degrees C) on the slide glass by dipping method. The average thickness of a coating film was measured to be about 0.25-0.30 microm. A coated film had a high refractive index over 1.88 at least irrespective of the heat-treatment even at room temperature drying and showed a super-hydrophilicity (< 5 degrees) after 20 minutes under Ultra Violet light irradiation, and it sustained in the darkness during a long period over 7 days depending on the heat-treatment conditions. Atomic Force Microscopic observation shows that the morphology of a heat-treated film had a relationship with the long-term hydrophilicity in the darkness.

  8. Titania nanotube powders obtained by rapid breakdown anodization in perchloric acid electrolytes

    NASA Astrophysics Data System (ADS)

    Ali, Saima; Hannula, Simo-Pekka

    2017-05-01

    Titania nanotube (TNT) powders are prepared by rapid break down anodization (RBA) in a 0.1 M perchloric acid (HClO4) solution (Process 1), and ethylene glycol (EG) mixture with HClO4 and water (Process 2). A study of the as-prepared and calcined TNT powders obtained by both processes is implemented to evaluate and compare the morphology, crystal structure, specific surface area, and the composition of the nanotubes. Longer TNTs are formed in Process 1, while comparatively larger pore diameter and wall thickness are obtained for the nanotubes prepared by Process 2. The TNTs obtained by Process 1 are converted to nanorods at 350 °C, while nanotubes obtained by Process 2 preserve tubular morphology till 350 °C. In addition, the TNTs prepared by an aqueous electrolyte have a crystalline structure, whereas the TNTs obtained by Process 2 are amorphous. Samples calcined till 450 °C have XRD peaks from the anatase phase, while the rutile phase appears at 550 °C for the TNTs prepared by both processes. The Raman spectra also show clear anatase peaks for all samples except the as-prepared sample obtained by Process 2, thus supporting the XRD findings. FTIR spectra reveal the presence of O-H groups in the structure for the TNTs obtained by both processes. However, the presence is less prominent for annealed samples. Additionally, TNTs obtained by Process 2 have a carbonaceous impurity present in the structure attributed to the electrolyte used in that process. While a negligible weight loss is typical for TNTs prepared from aqueous electrolytes, a weight loss of 38.6% in the temperature range of 25-600 °C is found for TNTs prepared in EG electrolyte (Process 2). A large specific surface area of 179.2 m2 g-1 is obtained for TNTs prepared by Process 1, whereas Process 2 produces nanotubes with a lower specific surface area. The difference appears to correspond to the dimensions of the nanotubes obtained by the two processes.

  9. Microwave electromagnetic properties of carbonyl iron particles and Si/C/N nano-powder filled epoxy-silicone coating

    NASA Astrophysics Data System (ADS)

    Qing, Yuchang; Zhou, Wancheng; Luo, Fa; Zhu, Dongmei

    2010-02-01

    The electromagnetic characteristics of carbonyl iron particles and Si/C/N nano-powder filled epoxy-silicone coatings were studied. The reflection loss of the coatings exceeds -10 dB at 8-18 GHz and -9 dB at 2-18 GHz when the coating thickness is 1 and 3 mm, respectively. The dielectric and magnetic absorbers filled coatings possess excellent microwave absorption, which could be attributed to the proper incorporate of the multi-polarization mechanisms as well as strong natural resonance. It is feasible to develop the thin and wideband microwave absorbing coatings using carbonyl iron particles and Si/C/N nano-powder.

  10. Synthesis and improved explosion behaviors of aluminum powders coated with nano-sized nickel film

    NASA Astrophysics Data System (ADS)

    Kim, Kyung Tae; Kim, Dong Won; Kim, Soo Hyung; Kim, Chang Kee; Choi, Yoon Jeong

    2017-09-01

    Nickel (Ni) materials with a thickness of a few hundred nm were homogeneously coated on the surfaces of aluminum (Al) powders by an electroless plating process. The Ni-coated Al powders show characteristic interfacial structures mixed of Ni, Al and O instead of densely packed Al oxide at the surface. The explosion test of the Ni-coated Al powders utilizing flame ignition showed that the powders had a 3.6 times enhanced pressurization rate of 405 kPa/ms compared to 111 kPa/ms of uncoated Al powders. It was found that this is due to a feasible diffusion of oxygen atoms into the Al powders through the thin and rough interfacial layers present at the Ni/Al interface. These results clearly indicate that nano-sized Ni film introduced instead of surface oxide acts as a very profitable layer to achieve efficient combustion behaviors by a rapid oxidation of Al powders.

  11. Synthesis of nano-forsterite powder by making use of natural silica sand

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Nurbaiti, Upik, E-mail: upik-nurbaiti@mail.unnes.ac.id; Department of Physics, Faculty of Mathematics and Natural Sciences Semarang State University Jl. Raya Sekaran GunungPati, Semarang 50221; Suud, Fikriyatul Azizah

    2016-02-08

    Nano-forsterite powder with natural silica sand and magnesium powder as the raw materials have been succesfully synthesized. The silica sand was purified followed by a coprecipitation process to obtain colloidal silica. The magnesium powder was dissolved in a chloric acid solution to obtain MgCl{sub 2} solution. The nanoforsterite powder was synthesised using a sol-gel method which included the mixing the colloidal silica and the MgCl{sub 2} solution with various aging and filtering processes. The samples were dried at 100 °C using a hot plate and then the dried powders were calcinated at 900 °C for 2 hours. The samples weremore » characetised for their elements and phase compositions using X-ray Flourescence (XRF) and X-ray Diffraction (XRD) methods, respectively. The diffraction data were qualitatively analyzed using Match!2 software and quantitatively using Rietica software. The crystallite size was verified using Transmission Electron Microscopy (TEM). Results of XRD data analysis showed that the forsterite content reached up to 90.5% wt. The TEM average crystallite size was approximately 53(6) nm.« less

  12. Ultrasonic-assisted preparation of nano eggshell powder: a novel catalyst in green and high efficient synthesis of 2-aminochromenes.

    PubMed

    Mosaddegh, Elaheh

    2013-11-01

    The nano eggshell powder (NESP) has been prepared by ultrasound irradiation and used as a novel and biodegradable catalyst with high catalytic activity and reusability in green synthesis of 2-aminochromenes via condensation of α- or β-phathol, malononitrile and aromatic aldehydes at 120 °C under solvent-free conditions. The reaction proceeds to completion within 10-35 min in 91-98% yield. Nano eggshell catalyst was characterized by scanning electron microscopy, X-ray powder diffraction, IR spectroscopy and X-ray fluorescence, thermal gravimetric, surface area and elemental analyses. In addition, the catalytic activity and chemical structure of nano-sized eggshell were compared with pure CaCO3. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. New High Aspect-Ratio Titania Nanotubes

    NASA Astrophysics Data System (ADS)

    Panaitescu, Eugen; Richter, Christiaan; Menon, Latika

    2007-03-01

    Titanium oxide nanotubes show great promise in photocatalytic, gas sensing, biological, and other applications. Techniques for the fabrication of titania nanotubes include electrodeposition in polymer molds starting from alumina templates, anodization of titanium in fluoride containing solutions, and hydrothermal treatment of nano- and micropowders. We have developed a new synthesis route for the production of new ultra-high aspect-ratio (over 1000:1) titania nanotubes by anodization in chloride containing acid solutions. The fabrication process occurs rapidly, in a fraction of the time when compared with other methods such as anodization in the highly toxic fluoride-containing electrolytes. We have demonstrated nanotubes with diameters as small as 25 nm, and lengths of up to 50 μm, and we have produced them with varying carbon content through the addition of organic acids in the electrolyte. This opens up new possibilities for many advanced applications of such nanotubes. Various synthesis conditions (pH, chloride content, electrolyte nature), and their influence on morphology, composition, and crystalline structure will be presented. Preliminary results on photocatalytic and transmission properties will also be discussed.

  14. Characterisation of Sol-Gel Synthesis of Phase Pure CaTiO3 Nano Powders after Drying

    NASA Astrophysics Data System (ADS)

    Mallik, P. K.; Biswal, G.; Patnaik, S. C.; Senapati, S. K.

    2015-02-01

    According to a few recent studies, calcium titanate (CT) is a material that is similar to hydroxyapatite in biological properties. However, calcium titanate is not currently being used in the biomedical applications as to hydroxyapatite. The objective is to prepare nano calcium titanate powders from the equimolar solution of calcium oxide, ethanol and Titanium (IV) isopropoxide via sol-gel synthesis. The phase analysis and morphology of powder particles were studied by X-ray diffraction (XRD), while the composition and size of powder particles were determined by Transmission electron microscope (TEM) attached with energy dispersive x-ray spectrometer (EDS). As results, XRD confirm the presence of phase pure crystalline CaTiO3 after drying at 100°C for 24 hours, while TEM analysis confirms about 13 nm sizes of CaTiO3 particles and some agglomerated particle of 20-30 nm. Moreover, EDS analysis indicates that the approximately stoichiometric Ca/Ti ratio 1:1 was obtained in the CaTiO3 powders. Finally, it can be concluded that described sol-gel synthesis could be novel method for the production of nano CaTiO3 particles at lower temperature compared to any other methods of production.

  15. Microwave-assisted synthesis of porous carbon-titania and highly crystalline titania nanostructures.

    PubMed

    Parker, Alison; Marszewski, Michal; Jaroniec, Mietek

    2013-03-01

    Porous carbon-titania and highly crystalline titania nanostructured materials were obtained through a microwave-assisted one-pot synthesis. Resorcinol and formaldehyde were used as carbon precursors, triblock copolymer Pluronic F127 as a stabilizing agent, and titanium isopropoxide as a titania precursor. This microwave-assisted one-pot synthesis involved formation of carbon spheres according to the recently modified Stöber method followed by hydrolysis and condensation of titania precursor. This method afforded carbon-titania composite materials containing anatase phase with specific surface areas as high as 390 m(2) g(-1). The pure nanostructured titania, obtained after removal of carbon through calcination of the composite material in air, was shown to be the anatase phase with considerably higher degree of crystallinity and the specific surface area as high as 130 m(2) g(-1). The resulting titania, because of its high surface area, well-developed porosity, and high crystallinity, is of great interest for catalysis, water treatment, lithium batteries, and other energy-related applications.

  16. Synthesis of Nano-Polycrystalline Synroc-B Powders as a High Level Radioactive Wastes Ceramic Forms by a Solution Combustion Synthesis.

    PubMed

    Han, Young-Min; Lee, Sang-Jin; Kim, Yeon-Ku; Jung, Choong-Hwan

    2016-02-01

    Synroc (Synthetic Rock) consists of four main titanate phases: peroveskite (CaTiO3), zirconolite (CaZrTi2O7), hollandite (BaAl2Ti6O16) and rutile (TiO2). Nano-polycrystalline synroc powders were made by a synthesis combustion process. The combustion process, an externally initiated reaction is self-sustained owing to the exothermic reaction. A significant volume of gas is evolved during the combustion reaction and leads to loosely agglomerated powders. This exothermic reaction provides necessary heat to further carry the reaction in forward direction to produce nanocrystalline powders as the final product. Glycine is used as a fuel, being oxidized by nitrate ions. It is inexpensive, has high energy efficiency, fast heating rates, short reaction times and high compositional homogeneity. In this study, combustion synthesis of nano-sized synroc-B powder is introduced. The fabrication of synroc-B powder result of observation XRD were prepared for polycrystalline (perovskite, zirconolite, hollandite, rutile) structures. The characterization of the synthesized powders is conducted by using XRD, SEM/EDS and TEM.

  17. Activity of titania and zeolite samples dosed with triethylamine

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Baker, Caitlin; Gole, James L.; Brauer, Jonathan

    2016-01-01

    Certain properties of titania and the ammonium- and proton-form of Y zeolites (silica/alumina ratio of 5.2) were explored before and after treatment by triethylamine (TEA). The effect of the triethylamine upon the physical and chemical properties of both titania and the zeolite were characterized by physical and chemical adsorption methods. BET surface area data showed enhanced surface area of the TEA-treated nanotitania over the untreated nanotitania whereas the TEA-treated zeolite showed a considerable decrease in surface area compared to the untreated zeolite. TPD of the TEA-treated Y zeolite showed that weakly adsorbed TEA left the surface between 150 and 300more » oC; strongly adsorbed TEA decomposed to ethylene and ammonia at higher temperatures. XPS, IR, and Raman spectroscopies, powder XRD, and 27Al MAS-NMR spectroscopy were used to further characterize the changes introduced by in-situ nitridation. Pre-adsorbed triethylamine decorated acid sites so as to neutralize these sites for the reaction of methanol to dimethylether. Carbon monoxide and ormaldehyde, products of the methanol probe reaction, were observed-- suggesting that basic sites are present in this treated zeolite and titania.« less

  18. Synthesis and characterization of nano TiO2-SiO2: PVA composite - a novel route

    NASA Astrophysics Data System (ADS)

    Venckatesh, Rajendran; Balachandaran, Kartha; Sivaraj, Rajeshwari

    2012-07-01

    A novel, simple, less time consuming and cost-effective sol-gel method has been developed to synthesize nano titania-silica with polyvinyl alcohol (PVA) composite relatively at low temperature in acidic pH. Titania sol is prepared by hydrolysis of titanium tetrachloride and was mixed with silicic acid and tetrahydrofuran mixture. The reaction was carried out under vigorous stirring for 6 h and dried at room temperature with the addition of PVA solution. The resulting powders were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared (FT-IR), UV-visible spectroscopy and thermal techniques. The grain size of the particles was calculated by X-ray diffraction; surface morphology and chemical composition were determined from scanning electron microscopy-energy dispersive spectroscopy; metal oxide stretching was confirmed from FT-IR spectroscopy; bandgap was calculated using UV-visible spectroscopy, and thermal stability of the prepared composite was determined by thermogravimetric/differential thermal analysis. Since TiO2 got agglomerated on the surface of SiO2, effective absorptive sites increase which in turn increase the photocatalytic efficiency of the resulting composite.

  19. Powder XRD, TEM, FTIR and thermal studies of strontium tartrate nano particles

    NASA Astrophysics Data System (ADS)

    Lathiya, U. M.; Jethva, H. O.; Joshi, M. J.; Vyas, P. M.

    2017-05-01

    Strontium tartrate finds several applications, e.g., as non-linear optical and dielectric material, in tracer composition and ammunition unit, in treating structural integrity of bone. The growth of single crystals of strontium tartrate in silica gel has been widely reported. In the present study, strontium tartrate nano particles were synthesized by wet chemical method using strontium chloride, tartaric acid and sodium meta-silicate solutions in the presence of Triton X -100 surfactant. It was found that the presence of sodium meta-silicate facilitated the reaction for strontium tartrate product. The powder XRD study of strontium tartrate nano-particles suggested monoclinic crystal system and the average crystallite size was found to be 40 nm determined by applying Scherrer's formula. The TEM analysis indicated that the nano particles were spherical in nature. The FTIR spectrum confirmed the presence of various functional groups such as O-H,C-H, and C=O stretching mode. The thermal analysis was carried out by using TGA and DTA studies. The nano-particles were found to be stable up to 175°C and then decomposed through various stages. The results are compared with the bulk crystalline material available in the literature.

  20. Preparation of ultra-fine powders from polysaccharide-coated solid lipid nanoparticles and nanostructured lipid carriers by innovative nano spray drying technology.

    PubMed

    Wang, Taoran; Hu, Qiaobin; Zhou, Mingyong; Xue, Jingyi; Luo, Yangchao

    2016-09-10

    In this study, five polysaccharides were applied as natural polymeric coating materials to prepare solid lipid nanoparticles (SLN) and nanostructure lipid carriers (NLC), and then the obtained lipid colloidal particles were transformed to solid powders by the innovative nano spray drying technology. The feasibility and suitability of this new technology to generate ultra-fine lipid powder particles were evaluated and the formulation was optimized. The spray dried SLN powder exhibited the aggregated and irregular shape and dimension, but small, uniform, well-separated spherical powder particles of was obtained from NLC. The optimal formulation of NLC was prepared by a 20-30% oleic acid content with carrageenan or pectin as coating material. Therefore, nano spray drying technology has a potential application to produce uniform, spherical, and sub-microscale lipid powder particles when the formulation of lipid delivery system is appropriately designed. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. A polymer solution technique for the synthesis of nano-sized Li 2TiO 3 ceramic breeder powders

    NASA Astrophysics Data System (ADS)

    Jung, Choong-Hwan; Lee, Sang Jin; Kriven, Waltraud M.; Park, Ji-Yeon; Ryu, Woo-Seog

    2008-02-01

    Nano-sized Li 2TiO 3 powder was fabricated by an organic-inorganic solution route. A steric entrapment route employing ethylene glycol was used for the preparation of the nano-sized Li 2TiO 3 particles. Titanium isopropoxide and lithium nitrate were dissolved in liquid-type ethylene glycol without any precipitation. With the optimum amount of the polymer, the metal cations (Li and Ti) were dispersed in the solution and a homogeneous polymeric network was formed. The organic-inorganic precursor gels were turned to crystalline powders through an oxidation reaction during a calcination process. The dried precursor gel showed the carbon-free Li 2TiO 3 crystalline form which was observed above 400 °C. The primary particle size of the carbon-free Li 2TiO 3 was about 70 nm, and the structure of the crystallized powder was porous and agglomerated. The powder compact was densified to 92% of TD at a relatively low sintering temperature of 1100 °C for 2 h.

  2. Phase transformation in the alumina-titania system during flash sintering experiments

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jha, S. K.; Lebrun, J. M.; Raj, R.

    2016-02-01

    We show that phase transformation in the alumina–titania system, which produces aluminum-titanate, follows an unusual trajectory during flash sintering. The experiments begin with mixed powders of alumina–titania and end in dense microstructures that are transformed into aluminum-titanate. The sintering and the phase transformation are separated in time, with the sintering occurs during Stage II, and phase transformation during Stage III of the flash sintering experiment. Stage III is the steady-state condition of flash activated state that is established under current control, while Stage II is the period of transition from voltage to current control. The extent of phase transformation increasesmore » with the current density and the hold time in Stage III.« less

  3. Sintering Effects on Morphology, Thermal Stability and Surface Area of Sol-Gel Derived Nano-Hydroxyapatite Powder

    NASA Astrophysics Data System (ADS)

    Kapoor, Seema; Batra, Uma; Kohli, Suchita

    2011-12-01

    Hydroxyapatite (HAP) ceramics have been recognized as substitute materials for bone and teeth in orthopedic and dentistry field due to their chemical and biological similarity to human hard tissue. The nanosized and nanocrystalline forms of HAP have great potential to revolutionize the hard tissue-engineering field, starting from bone repair and augmentation to controlled drug delivery systems. This paper reports the synthesis of biomimetic nano-hydroxyapatite (HAP) by sol-gel method using calcium nitrate tetrahydrate (CNT) and potassium dihydrogen phosphate (KDP) as calcium and phosphorus precursors, respectively to obtain a desired Ca/P ratio of 1.67. Deionized water was used as a diluting media for HAP sol preparation and ammonia was used to adjust the pH to 11. After aging, the HAP gel was dried at 55 °C and sintered to different temperatures (200 °C, 400 °C, 600 °C, 800 °C, 1000 °C and 1200 °C). The dried and sintered powders were characterized for phase composition using Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). The particle size and morphology was studied using transmission electron microscopy (TEM). The thermal behavior of the dried HAP nanopowder was studied in the temperature range of 55 °C to 1000 °C using thermal gravimetric analyser (TGA). The BET surface area of absorbance was determined by Nitrogen adsorption using Brunauer-Emmett-Teller (BET) method. The presence of characteristic peaks of the phosphate and OH groups in FTIR spectrums confirmed the formation of pure HAP in dried as well as sintered powders. XRD results also confirmed the formation of stoichiometric nano-HAP. Sintering revealed that with increase in temperature, both the crystallinity and crystallite size of nano-HAP particles increased. The synthesized nano-HAP powder was found to be stable upto 1000 °C without any additional phase other than HAP, whereas peak of β-TCP (tricalcium phosphate) was observed at 1200 °C. Photomicrograph of

  4. The influence of Span-20 surfactant and micro-/nano-Chromium (Cr) Powder Mixed Electrical Discharge Machining (PMEDM) on the surface characteristics of AISI D2 hardened steel

    NASA Astrophysics Data System (ADS)

    Hosni, N. A. J.; Lajis, M. A.

    2018-04-01

    The application of powder mixed dielectric to improve the efficiency of electrical discharge machining (EDM) has been extensively studied. Therefore, PMEDM have attracted the attention of many researchers since last few decades. Improvement in EDM process has resulted in the use of span-20 surfactant and Cr powder mixed in dielectric fluid, which results in increasing machiniability, better surface quality and faster machining time. However, the study of powder suspension size of surface charateristics in EDM field is still limited. This paper presents the improvement of micro-/nano- Cr powder size on the surface characteristics of the AISI D2 hardened steels in PMEDM. It has found that the reacst layer in PMEDM improved by as high as 41-53 % compared to conventional EDM. Also notably, the combination of added Cr powder and span-20 surfactant reduced the recast layer thickness significantly especially in nano-Cr size. This improvement was great potential adding nano-size Cr powder to dielectric for machining performance.

  5. Fabrication of complete titania nanoporous structures via electrochemical anodization of Ti

    PubMed Central

    2011-01-01

    We present a novel method to fabricate complete and highly oriented anodic titanium oxide (ATO) nano-porous structures with uniform and parallel nanochannels. ATO nano-porous structures are fabricated by anodizing a Ti-foil in two different organic viscous electrolytes at room temperature using a two-step anodizing method. TiO2 nanotubes covered with a few nanometer thin nano-porous layer is produced when the first and the second anodization are carried out in the same electrolyte. However, a complete titania nano-porous (TNP) structures are obtained when the second anodization is conducted in a viscous electrolyte when compared to the first one. TNP structure was attributed to the suppression of F-rich layer dissolution between the cell boundaries in the viscous electrolyte. The structural morphologies were examined by field emission scanning electron microscope. The average pore diameter is approximately 70 nm, while the average inter-pore distance is approximately 130 nm. These TNP structures are useful to fabricate other nanostructure materials and nanodevices. PMID:21711844

  6. Sonocatalytic degradation of some dyestuffs and comparison of catalytic activities of nano-sized TiO2, nano-sized ZnO and composite TiO2/ZnO powders under ultrasonic irradiation.

    PubMed

    Wang, Jun; Jiang, Zhe; Zhang, Liqun; Kang, Pingli; Xie, Yingpeng; Lv, Yanhui; Xu, Rui; Zhang, Xiangdong

    2009-02-01

    Here, a novel sonocatalyst, composite TiO2/ZnO powder, was prepared through the combination of nano-sized TiO2 and ZnO powders. Because of the appropriate adsorbability to organic pollutants and special crystal interphase between TiO2 and ZnO particles, the composite TiO2/ZnO powder exhibits a high sonocatalytic activity under ultrasonic irradiation during the degradation of acid red B. Especially, the sonocatalytic activity of composite TiO2/ZnO powder with 4:1 molar proportion treated at 500 degrees C for 50 min showed obvious improvement compared with pure nano-sized TiO2 and ZnO powders. When the experimental conditions such as 10mg/L acid red B concentration, 1.0 g/L catalyst addition amount, pH=7.0, 20 degrees C system temperature, 100 min ultrasonic time and 50 mL total volume were adopted, the satisfactory degradation ratio and rate were obtained. All experiments indicate that the sonocatalytic method using composite TiO2/ZnO powder may be a more advisable choice for the treatments of non- or low-transparent organic wastewaters in future.

  7. Synthesis of nano anatase for titanosilicate ETS-10 synthesis

    NASA Astrophysics Data System (ADS)

    Shafeque, Shihara

    Functionalized textiles present a vast and growing niche in the global textile market at US $400 billion [1, 2]. Engelhard Titanium Silicate 10 (ETS-10), a photocatalytic zeo-type material if coated on textiles, is expected to impart useful properties similar to TiO2, such as stain-resistant, odor repellant, bactericidal and enhanced UV protection [3, 4]. Typically, small ETS-10 crystals of size ˜300-800 nm are synthesized using solid titania (e.g., anatase or P25) sources [5, 6, 7]. However, smaller ETS-10 crystals are required for a uniform surface coating with highly effective surface area. The dissolution of titania particles (i.e., their size) is hypothesized to be important in small ETS-10 crystal formation [5, 6, 7]. Nano anatase was synthesized by modification of two methods: direct precipitation [7] and sol-gel synthesis [3]. Analysis by XRD confirmed that both methods produced nano anatase of crystallite size ˜4-5 nm. However, FE-SEM analysis showed that product from direct precipitation, existed as intergrown spheroidal particles with size ˜1.0 mum. These particles dispersed poorly in deionized water. Therefore, the best nano anatase samples were from sol-gel synthesis in two forms, dry powder and colloidal anatase. ETS-10 synthesis was investigated using two methods adopted from literature [6, 7]. The method of Yoon and co-workers [7], with nano anatase in a molar composition of 5.5TEOS: TiO2: 8.4NaOH: 1.43KF: 350H2O: 2.2H2SO4 produced unknown phase(s) with some ETS-10 and quartz. Using colloidal anatase with molar composition 5.5TEOS:1.0TiO 2:8.4NaOH:1.43KF:400H2O:2.2H2SO4 also produced unknown phase(s). The method of Anderson and co-workers [6] with nano anatase powder in a molar composition of 5.5SiO2: TiO 2: 5.2Na2O: 0.5K2O: 113H2O produced quartz with ETS-10 impurity. When colloidal anatase was used, with molar composition TiO2:5.5SiO2:5.2Na2O:0.5K2O:332H 2O, unreacted anatase and quartz were formed. It was hypothesized that the very low

  8. Laser ablation ICP-MS analysis on nano-powder pellets and applications to granite bulk rock analysis

    NASA Astrophysics Data System (ADS)

    Wu, Shitou; Karius, Volker; Wörner, Gerhard

    2017-04-01

    Granites are a ubiquitous component of the continental crust and knowing their precise trace element signatures is essential in understanding the origins and evolution of the continental crust. ICP-MS bulk analysis of granite is generally conducted on solution after acid-digestion. However this technique has several deficiencies related to the difficulty of completely dissolving accessary minerals such as zircon and the instability/adsorption of high valence trace elements (Nb, Ta et al.) in acid solutions. The development of a nano-powder pellet technique by using wet milling procedure, and its combination with laser ablation ICP-MS has been proposed to overcome these problems. In this study, we produced nano-powders from a series of granite rock standards by wet milling in agate using a high power planetary ball mill instrument. The procedure was tested and optimized by modifying parameters (ball to powder ratio, water to powder ratio, milling power etc.). Characterization of nano-powders was conducted by various techniques including electron microprobe (EMP), secondary electron imaging, polarizing microscope, and laser particle size analyzer (LPSA) and laser scanning confocal microscope (LSCM). Particle sizes range from a few nm to 5 μm with a small secondary mode at around 10 to 20 μm that probably represent particle aggregates rather than remaining crystal grains after milling. Pellets of 5 mm in diameter were pressed into molds of cellulose at 1.75 *103 N/cm2. Surface roughness of the pellets was measured by LSCM and gave a Ra of 0.494 μm, which is an order higher than the surface of polished ATGH-G reference glass surface (Ra: 0.048 μm), but sufficient for laser ablation. Sources of contamination either from abrading agate balls or from ultrapure water were evaluated and quantified. The homogeneity of powder pellets down to less than 5 μm size was documented based on EMPA element mapping and statistical analyses of LA-ICP-MS in discrete spot and line

  9. N-type nano-silicon powders with ultra-low electrical resistivity as anode materials in lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Yue, Zhihao; Zhou, Lang; Jin, Chenxin; Xu, Guojun; Liu, Liekai; Tang, Hao; Li, Xiaomin; Sun, Fugen; Huang, Haibin; Yuan, Jiren

    2017-06-01

    N-type silicon wafers with electrical resistivity of 0.001 Ω cm were ball-milled to powders and part of them was further mechanically crushed by sand-milling to smaller particles of nano-size. Both the sand-milled and ball-milled silicon powders were, respectively, mixed with graphite powder (silicon:graphite = 5:95, weight ratio) as anode materials for lithium ion batteries. Electrochemical measurements, including cycle and rate tests, present that anode using sand-milled silicon powder performed much better. The first discharge capacity of sand-milled silicon anode is 549.7 mAh/g and it is still up to 420.4 mAh/g after 100 cycles. Besides, the D50 of sand-milled silicon powder shows ten times smaller in particle size than that of ball-milled silicon powder, and they are 276 nm and 2.6 μm, respectively. In addition, there exist some amorphous silicon components in the sand-milled silicon powder excepting the multi-crystalline silicon, which is very different from the ball-milled silicon powder made up of multi-crystalline silicon only.

  10. Nitrogen-modified nano-titania: True phase composition, microstructure and visible-light induced photocatalytic NOx abatement

    NASA Astrophysics Data System (ADS)

    Tobaldi, D. M.; Pullar, R. C.; Gualtieri, A. F.; Otero-Irurueta, G.; Singh, M. K.; Seabra, M. P.; Labrincha, J. A.

    2015-11-01

    Titanium dioxide (TiO2) is a popular photocatalyst used for many environmental and anti-pollution applications, but it normally operates under UV light, exploiting ∼5% of the solar spectrum. Nitrification of titania to form N-doped TiO2 has been explored as a way to increase its photocatalytic activity under visible light, and anionic doping is a promising method to enable TiO2 to harvest visible-light by changing its photo-absorption properties. In this paper, we explore the insertion of nitrogen into the TiO2 lattice using our green sol-gel nanosynthesis method, used to create 10 nm TiO2 NPs. Two parallel routes were studied to produce nitrogen-modified TiO2 nanoparticles (NPs), using HNO3+NH3 (acid-precipitated base-peptised) and NH4OH (totally base catalysed) as nitrogen sources. These NPs were thermally treated between 450 and 800 °C. Their true phase composition (crystalline and amorphous phases), as well as their micro-/nanostructure (crystalline domain shape, size and size distribution, edge and screw dislocation density) was fully characterised through advanced X-ray methods (Rietveld-reference intensity ratio, RIR, and whole powder pattern modelling, WPPM). As pollutants, nitrogen oxides (NOx) are of particular concern for human health, so the photocatalytic activity of the NPs was assessed by monitoring NOx abatement, using both solar and white-light (indoor artificial lighting), simulating outdoor and indoor environments, respectively. Results showed that the onset of the anatase-to-rutile phase transformation (ART) occurred at temperatures above 450 °C, and NPs heated to 450 °C possessed excellent photocatalytic activity (PCA) under visible white-light (indoor artificial lighting), with a PCA double than that of the standard P25 TiO2 NPs. However, higher thermal treatment temperatures were found to be detrimental for visible-light photocatalytic activity, due to the effects of four simultaneous occurrences: (i) loss of OH groups and water adsorbed

  11. Titania bound sodium titanate ion exchanger

    DOEpatents

    DeFilippi, Irene C. G.; Yates, Stephen Frederic; Shen, Jian-Kun; Gaita, Romulus; Sedath, Robert Henry; Seminara, Gary Joseph; Straszewski, Michael Peter; Anderson, David Joseph

    1999-03-23

    This invention is method for preparing a titania bound ion exchange composition comprising admixing crystalline sodium titanate and a hydrolyzable titanium compound and, thereafter drying the titania bound crystalline sodium titanate and subjecting the dried titania bound ion exchange composition to optional compaction and calcination steps to improve the physical strength of the titania bound composition.

  12. Noble metal-modified titania with visible-light activity for the decomposition of microorganisms

    PubMed Central

    Endo, Maya; Wei, Zhishun; Wang, Kunlei; Karabiyik, Baris; Yoshiiri, Kenta; Rokicka, Paulina; Ohtani, Bunsho

    2018-01-01

    Commercial titania photocatalysts were modified with silver and gold by photodeposition, and characterized by diffuse reflectance spectroscopy (DRS), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning transmission electron microscopy (STEM). It was found that silver co-existed in zero valent (core) and oxidized (shell) forms, whereas gold was mainly zero valent. The obtained noble metal-modified samples were examined with regard to antibacterial (Escherichia coli (E. coli)) and antifungal (Aspergillus niger (A. niger), Aspergillus melleus (A. melleus), Penicillium chrysogenum (P. chrysogenum), Candida albicans (C. albicans)) activity under visible-light irradiation and in the dark using disk diffusion, suspension, colony growth (“poisoned food”) and sporulation methods. It was found that silver-modified titania, besides remarkably high antibacterial activity (inhibition of bacterial proliferation), could also decompose bacterial cells under visible-light irradiation, possibly due to an enhanced generation of reactive oxygen species and the intrinsic properties of silver. Gold-modified samples were almost inactive against bacteria in the dark, whereas significant bactericidal effect under visible-light irradiation suggested that the mechanism of bacteria inactivation was initiated by plasmonic excitation of titania by localized surface plasmon resonance of gold. The antifungal activity tests showed efficient suppression of mycelium growth by bare titania, and suppression of mycotoxin generation and sporulation by gold-modified titania. Although, the growth of fungi was hardly inhibited through disc diffusion (inhibition zones around discs), it indicates that gold does not penetrate into the media, and thus, a good stability of plasmonic photocatalysts has been confirmed. In summary, it was found that silver-modified titania showed superior antibacterial activity, whereas gold-modified samples were very active against fungi

  13. Non-Metal Doped Titania Photocatalysts for the Degradation of Neonicotinoid Insecticides Under Visible Light Irradiation.

    PubMed

    Joseph, Amala Infant Joice; Thiripuranthagan, Sivakumar

    2018-05-01

    Recombination of e-/h+ pair, the major issue of any titania based photocatalytic material, is addressed here by doping non-metals such as C, N, B, F into the lattice of nano TiO2. The as-synthesised catalysts were characterized by using various instrumental techniques such as X-ray diffraction (XRD), UV-Diffuse reflectance spectroscopy (UV-DRS), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Nanosize of titania was confirmed by both XRD and TEM studies. Visible light inactivity of TiO2 is overcome by C, N, B, F doped titania catalysts in the degradation of neonicotinoid type insecticides namely imidacloprid (IMI) and thiamethoxam (TMX). The degradation efficiencies of the catalysts under different irradiations namely UV, visible and solar were compared. Among the catalysts, CNBF/TiO2 degraded IMI completely at 150, 240 and 330 min whereas TMX has been degraded completely at 210, 270 and 420 min under UV, solar and visible irradiations respectively. The recyclability test of CNBF/TiO2 confirmed its stability towards photocatalytic reaction.

  14. [Preparation of nano-nacre artificial bone].

    PubMed

    Chen, Jian-ting; Tang, Yong-zhi; Zhang, Jian-gang; Wang, Jian-jun; Xiao, Ying

    2008-12-01

    To assess the improvements in the properties of nano-nacre artificial bone prepared on the basis of nacre/polylactide acid composite artificial bone and its potential for clinical use. The compound of nano-scale nacre powder and poly-D, L-lactide acid (PDLLA) was used to prepare the cylindrical hollow artificial bone, whose properties including raw material powder scale, pore size, porosity and biomechanical characteristics were compared with another artificial bone made of micron-scale nacre powder and PDLLA. Scanning electron microscope showed that the average particle size of the nano-nacre powder was 50.4-/+12.4 nm, and the average pore size of the artificial bone prepared using nano-nacre powder was 215.7-/+77.5 microm, as compared with the particle size of the micron-scale nacre powder of 5.0-/+3.0 microm and the pore size of the resultant artificial bone of 205.1-/+72.0 microm. The porosities of nano-nacre artificial bone and the micron-nacre artificial bone were (65.4-/+2.9)% and (53.4-/+2.2)%, respectively, and the two artificial bones had comparable compressive strength and Young's modulus, but the flexural strength of the nano-nacre artificial bone was lower than that of the micro-nacre artificial bone. The nano-nacre artificial bone allows better biodegradability and possesses appropriate pore size, porosity and biomechanical properties for use as a promising material in bone tissue engineering.

  15. Enhanced Raman spectroscopy of 2,4,6-TNT in anatase and rutile titania nanocrystals

    NASA Astrophysics Data System (ADS)

    De La Cruz-Montoya, Edwin; Jeréz, Jaqueline I.; Balaguera-Gelves, Marcia; Luna-Pineda, Tatiana; Castro, Miguel E.; Hernández-Rivera, Samuel P.

    2006-05-01

    The majority of explosives found in antipersonnel and antitank landmines contain 2,4,6-trinitrotoluene (TNT). Chemical sensing of landmines and Improvised Explosive Devices (IED) requires detecting the chemical signatures of the explosive components in these devices. Nanotechnology is ideally suited to needs in microsensors development by providing new materials and methods that can be employed for trace explosive detection. This work is focused on modification of nano-scaled colloids of titanium dioxide (Titania: anatase, rutile and brookite) and thin layer of the oxides as substrates for use in Enhanced Raman Scattering (ERS) spectroscopy. Ultrafine particles have been generated by hydrothermally treating the sol-gel derived hydrous oxides. ERS spectra of nanocrystalline anatase Titania samples prepared with different average sizes: 38 nm (without acid), 24 nm (without acid) and 7 nm (with HCl). Bulk phase (commercial) and KBr were also used to prepare mixtures with TNT to look for Enhanced Raman Effect of the nitroaromatic explosive on the test surfaces. The studies clearly indicated that the anatase crystal size affects the enhancement of the TNT Raman signal. This enhancement was highest for the samples with Titania average crystal size of 7 nm.

  16. History of ``NANO''-Scale VERY EARLY Solid-State (and Liquid-State) Physics/Chemistry/Metallurgy/ Ceramics; Interstitial-Alloys Carbides/Nitrides/Borides/...Powders and Cermets, Rock Shocks, ...

    NASA Astrophysics Data System (ADS)

    Maiden, Colin; Siegel, Edward

    History of ``NANO'': Siegel-Matsubara-Vest-Gregson[Mtls. Sci. and Eng. 8, 6, 323(`71); Physica Status Solidi (a)11,45(`72)] VERY EARLY carbides/nitrides/borides powders/cermets solid-state physics/chemistry/metallurgy/ ceramics FIRST-EVER EXPERIMENTAL NANO-physics/chemistry[1968 ->Physica Status Solidi (a)11,45(`72); and EARLY NANO-``physics''/NANO-``chemistry'' THEORY(after: Kubo(`62)-Matsubara(`60s-`70s)-Fulde (`65) [ref.: Sugano[Microcluster-Physics, Springer('82 `98)

  17. Amorphous titania modified with boric acid for selective capture of glycoproteins.

    PubMed

    Jin, Shanxia; Liu, Liping; Zhou, Ping

    2018-05-22

    Amorphous titania was modified with boric acid, and the resulting material was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray powder diffraction and X-ray photoelectron spectrometry. The new material, in contrast to conventional boronate affinity materials containing boronic acid ligands, bears boric acid groups. It is shown to exhibit high specificity for glycoproteins, and this was applied to design a method for solid phase extraction of glycoproteins as shown for ribonuclease B, horse radish peroxidase and ovalbumin. Glycoproteins were captured under slightly alkaline environment and released in acidic solutions. The glycoproteins extracted were detected by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The binding capacities for ribonuclease B, horse radish peroxidase and ovalbumin typically are 9.3, 26.0 and 53.0 mg ∙ g -1 , respectively. The method was successfully applied to the selective enrichment of ovalbumin from egg white. Graphical abstract Schematic presentation of the capture of glycoproteins by amorphous titania modified with boric acid.

  18. Biomedical applications of nano-titania in theranostics and photodynamic therapy.

    PubMed

    Rehman, F U; Zhao, C; Jiang, H; Wang, X

    2016-01-01

    Titanium dioxide (TiO2) is one of the most abundantly used nanomaterials for human life. It is used in sunscreen, photovoltaic devices, biomedical applications and as a food additive and environmental scavenger. Nano-TiO2 in biomedical applications is well documented. It is used in endoprosthetic implants and early theranostics of neoplastic and non-neoplastic maladies as a photodynamic therapeutic agent and as vehicles in nano-drug delivery systems. Herein, we focus on the recent advancements and applications of nano-TiO2 in bio-nanotechnology, nanomedicine and photodynamic therapy (PDT).

  19. Bacteria-assisted preparation of nano α-Fe2O3 red pigment powders from waste ferrous sulfate.

    PubMed

    Li, Xiang; Wang, Chuankai; Zeng, Yu; Li, Panyu; Xie, Tonghui; Zhang, Yongkui

    2016-11-05

    Massive ferrous sulfate with excess sulfuric acid is produced in titanium dioxide industry each year, ending up stockpiled or in landfills as solid waste, which is hazardous to environment and in urgent demand to be recycled. In this study, waste ferrous sulfate was used as a second raw material to synthesize nano α-Fe2O3 red pigment powders with a bacteria-assisted oxidation process by Acidithiobacillus ferrooxidans. The synthesis route, mainly consisting of bio-oxidation, precipitation and calcination, was investigated by means of titration, thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscope (SEM) and X-ray fluorescence (XRF) to obtain optimum conditions. Under the optimum conditions, nano α-Fe2O3 red pigment powders contained 98.24wt.% of Fe2O3 were successfully prepared, with a morphology of spheroidal and particle size ranged from 22nm to 86nm and averaged at 45nm. Moreover, the resulting product fulfilled ISO 1248-2006, the standards of iron oxide pigments. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Synthesis of TiO2 nano-powders prepared from purified sulphate leach liquor of red mud.

    PubMed

    Tsakiridis, P E; Oustadakis, P; Katsiapi, A; Perraki, M; Agatzini-Leonardou, S

    2011-10-30

    The research work presented in this paper is focused on the development of a purification process of red mud sulphate leach liquor for the recovery of titanium oxide (TiO(2)) nano-powders in the form of anatase. Initially, titanium was extracted over iron and aluminium from the leach liquor by solvent extraction using Cyanex 272 in toluene, at pH: 0.3 and T: 25°C, with 40% extractant concentration. Stripping of the loaded, with titanium, organic phase was carried out by diluted HCl (3 mol/L) at ambient temperature. Finally, the recovery of titanium nano-powder, in the form of anatase, was performed by chemical precipitation at pH: 6 and T: 95°C, using 10 wt% MgO pulp as neutralizing agent. The produced precipitates were characterized by X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric/differential thermal analysis (TGA/DTA). Their morphological characteristics and microstructure were studied by scanning electron microscopy (SEM). High grade titanium white precipitate, in the form of anatase, was obtained. Iron concentration in the precipitate did not exceed 0.3%, whereas no aluminium was detected. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. Thermal decomposition behavior of nano/micro bimodal feedstock with different solids loading

    NASA Astrophysics Data System (ADS)

    Oh, Joo Won; Lee, Won Sik; Park, Seong Jin

    2018-01-01

    Debinding is one of the most critical processes for powder injection molding. The parts in debinding process are vulnerable to defect formation, and long processing time of debinding decreases production rate of whole process. In order to determine the optimal condition for debinding process, decomposition behavior of feedstock should be understood. Since nano powder affects the decomposition behavior of feedstock, nano powder effect needs to be investigated for nano/micro bimodal feedstock. In this research, nano powder effect on decomposition behavior of nano/micro bimodal feedstock has been studied. Bimodal powders were fabricated with different ratios of nano powder, and the critical solids loading of each powder was measured by torque rheometer. Three different feedstocks were fabricated for each powder depending on solids loading condition. Thermogravimetric analysis (TGA) experiment was carried out to analyze the thermal decomposition behavior of the feedstocks, and decomposition activation energy was calculated. The result indicated nano powder showed limited effect on feedstocks in lower solids loading condition than optimal range. Whereas, it highly influenced the decomposition behavior in optimal solids loading condition by causing polymer chain scission with high viscosity.

  2. Silver ion doped ceramic nano-powder coated nails prevent infection in open fractures: In vivo study.

    PubMed

    Kose, Nusret; Çaylak, Remzi; Pekşen, Ceren; Kiremitçi, Abdurrahman; Burukoglu, Dilek; Koparal, Savaş; Doğan, Aydın

    2016-02-01

    Despite improvement in operative techniques and antibiotic therapy, septic complications still occur in open fractures. We developed silver ion containing ceramic nano powder for implant coating to provide not only biocompatibility but also antibacterial activity to the orthopaedic implants. We hypothesised silver ion doped calcium phosphate based ceramic nano-powder coated titanium nails may prevents bacterial colonisation and infection in open fractures as compared with uncoated nails. 33 rabbits divided into three groups. In the first group uncoated, in the second group hydroxyapatite coated, and in the third group silver doped hydroxyapatite coated titanium nails were inserted left femurs of animals from knee regions with retrograde fashion. Before implantation of nails 50 μl solution containing 10(6)CFU/ml methicillin resistance Staphylococcus aureus (MRSA) injected intramedullary canal. Rabbits were monitored for 10 weeks. Blood was taken from rabbits before surgery and on 2nd, 6th and 10th weeks. Blood was analysed for biochemical parameters, blood count, C-reactive protein and silver levels. At the end of the 10 weeks animals were sacrificed and rods were extracted in a sterile fashion. Swab cultures were taken from intramedullary canal. Bacteria on titanium rods were counted. Liver, heart, spleen, kidney and central nervous tissues samples were taken for determining silver levels. Histopathological evaluation of bone surrounding implants was also performed. No significant difference was detected between the groups from hematologic, biochemical, and toxicological aspect. Microbiological results showed that less bacterial growth was detected with the use of silver doped ceramic coated implants compared to the other two groups (p=0.003). Accumulation of silver was not detected. No cellular inflammation was observed around the silver coated prostheses. No toxic effect of silver on bone cells was seen. Silver ion doped calcium phosphate based ceramic nano

  3. Synthesis and mechanical behavior of β-tricalcium phosphate/titania composites addressed to regeneration of long bone segments.

    PubMed

    Sprio, Simone; Guicciardi, Stefano; Dapporto, Massimiliano; Melandri, Cesare; Tampieri, Anna

    2013-01-01

    Bioactive tricalcium phosphate/titania ceramic composites were synthesized by pressureless air sintering of mixed hydroxyapatite and titania (TiO2) powders. The sintering process was optimized to achieve dense ceramic bodies consisting in a bioactive/bioresorbable matrix (β-tricalcium phosphate) reinforced with defined amounts of sub-micron sized titania particles. Extensive chemico-physical and mechanical characterization was carried out on the resulting composites, which displayed values of flexural strength, fracture toughness and elastic modulus in the range or above the typical ranges of values manifested by human cortical bone. It was shown that titania particles provided a toughening effect to the calcium-phosphate matrix and a reinforcement in fracture strength, in comparison with sintered hydroxyapatite bodies characterized by similar relative density. The characteristics of the resulting composites, i.e. bioactivity/bioresorbability and ability of manifesting biomimetic mechanical behavior, are features that can promote processes of bone regeneration in load-bearing sites. Hence, in the perspective of developing porous bone scaffolds with high bioactivity and improved biomechanical behavior, TCP/TiO2 composites with controlled composition can be considered as very promising biomaterials for application in a field of orthopedics where no acceptable clinical solutions still exist. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Nitrogen-modified nano-titania: True phase composition, microstructure and visible-light induced photocatalytic NO{sub x} abatement

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tobaldi, D.M., E-mail: david.tobaldi@ua.pt; Pullar, R.C.; Gualtieri, A.F.

    2015-11-15

    Titanium dioxide (TiO{sub 2}) is a popular photocatalyst used for many environmental and anti-pollution applications, but it normally operates under UV light, exploiting ∼5% of the solar spectrum. Nitrification of titania to form N-doped TiO{sub 2} has been explored as a way to increase its photocatalytic activity under visible light, and anionic doping is a promising method to enable TiO{sub 2} to harvest visible-light by changing its photo-absorption properties. In this paper, we explore the insertion of nitrogen into the TiO{sub 2} lattice using our green sol–gel nanosynthesis method, used to create 10 nm TiO{sub 2} NPs. Two parallel routesmore » were studied to produce nitrogen-modified TiO{sub 2} nanoparticles (NPs), using HNO{sub 3}+NH{sub 3} (acid-precipitated base-peptised) and NH{sub 4}OH (totally base catalysed) as nitrogen sources. These NPs were thermally treated between 450 and 800 °C. Their true phase composition (crystalline and amorphous phases), as well as their micro-/nanostructure (crystalline domain shape, size and size distribution, edge and screw dislocation density) was fully characterised through advanced X-ray methods (Rietveld-reference intensity ratio, RIR, and whole powder pattern modelling, WPPM). As pollutants, nitrogen oxides (NO{sub x}) are of particular concern for human health, so the photocatalytic activity of the NPs was assessed by monitoring NO{sub x} abatement, using both solar and white-light (indoor artificial lighting), simulating outdoor and indoor environments, respectively. Results showed that the onset of the anatase-to-rutile phase transformation (ART) occurred at temperatures above 450 °C, and NPs heated to 450 °C possessed excellent photocatalytic activity (PCA) under visible white-light (indoor artificial lighting), with a PCA double than that of the standard P25 TiO{sub 2} NPs. However, higher thermal treatment temperatures were found to be detrimental for visible-light photocatalytic activity, due to the

  5. Preparation of UO2, ThO2 and (Th,U)O2 pellets from photochemically-prepared nano-powders

    NASA Astrophysics Data System (ADS)

    Pavelková, Tereza; Čuba, Václav; de Visser-Týnová, Eva; Ekberg, Christian; Persson, Ingmar

    2016-02-01

    Photochemically-induced preparation of nano-powders of crystalline uranium and/or thorium oxides and their subsequent pelletizing has been investigated. The preparative method was based on the photochemically induced formation of amorphous solid precursors in aqueous solution containing uranyl and/or thorium nitrate and ammonium formate. The EXAFS analyses of the precursors shown that photon irradiation of thorium containing solutions yields a compound with little long-range order but likely "ThO2 like" and the irradiation of uranium containing solutions yields the mixture of U(IV) and U(VI) compounds. The U-containing precursors were carbon free, thus allowing direct heat treatment in reducing atmosphere without pre-treatment in the air. Subsequent heat treatment of amorphous solid precursors at 300-550 °C yielded nano-crystalline UO2, ThO2 or solid (Th,U)O2 solutions with high purity, well-developed crystals with linear crystallite size <15 nm. The prepared nano-powders of crystalline oxides were pelletized without any binder (pressure 500 MPa), the green pellets were subsequently sintered at 1300 °C under an Ar:H2 (20:1) mixture (UO2 and (Th,U)O2 pellets) or at 1600 °C in ambient air (ThO2 pellets). The theoretical density of the sintered pellets varied from 91 to 97%.

  6. Preparation of nano fluids by mechanical method

    NASA Astrophysics Data System (ADS)

    Boopathy, J.; Pari, R.; Kavitha, M.; Angelo, P. C.

    2012-07-01

    Nanofluids are conventional heat transfer fluids that contain nano particles of metals, oxides, carbides, nitrides, or nanotubes. Nanofluids exhibit enhanced thermal conductivity and heat transfer coefficients compared to the base fluids. This paper presents the procedure for preparing nanofluids consisting of Copper and Aluminium nano powders in base fluids. Copper and Aluminium nano powders were produced by planetary ball wet milling at 300rpm for 50hrs. Toluene was added to ensure wet milling. These powders were characterized in XRD and SEM for their purity, particle size and shape. The XRD results confirmed the final particle sizes of Copper and Aluminium in the nano range. Then the 0.01 gm of nano metal powders was added in 150 ml of double distilled water and magnetic stirring was done at 1500 rpm for 15 minutes. Sodium lauryl sulphate (0.05%) was added in water as surfactant to ensure the stability of the dispersion. Ultrasonication in the 3000 watts bath was done for 10 minutes to enhance the uniform dispersion of metal powders in water. The pH, dynamic viscosity, ionic conductivity and the stability of the fluids were determined for further usage of synthesized nanofluids as coolant during grinding operation.

  7. Amorphous titania/carbon composite electrode materials

    DOEpatents

    Vaughey, John T.; Jansen, Andrew; Joyce, Christopher D.

    2017-05-09

    An isolated salt comprising a compound of formula (H.sub.2X)(TiO(Y).sub.2) or a hydrate thereof, wherein X is 1,4-diazabicyclo[2.2.2]octane (DABCO), and Y is oxalate anion (C.sub.2O.sub.4.sup.-2), when heated in an oxygen-containing atmosphere at a temperature in the range of at least about 275.degree. C. to less than about 400.degree. C., decomposes to form an amorphous titania/carbon composite material comprising about 40 to about 50 percent by weight titania and about 50 to about 60 percent by weight of a carbonaceous material coating the titania. Heating the composite material at a temperature of about 400 to 500.degree. C. crystallizes the titania component to anatase. The titania materials of the invention are useful as components of the cathode or anode of a lithium or lithium ion electrochemical cell.

  8. Commercial and home-made nitrogen modified titanias. A short reflection about the advantageous/disadvantageous properties of nitrogen doping in the frame of their applicability

    NASA Astrophysics Data System (ADS)

    Pap, Zs.; Mogyorósi, K.; Veréb, G.; Dombi, A.; Hernádi, K.; Danciu, V.; Baia, L.

    2014-09-01

    As visible light driven photocatalysis became more and more intensively studied, the first commercial products showed up on the market. Simultaneously controversial results appeared in the literature generating an intensive debate regarding the advantages and draw-backs of nitrogen doping of titania. Hence, the present work focuses on two commercially available and four sol-gel made nitrogen modified titania powders regarding their structure and activity. It is demonstrated that the interstitial nitrogen entities “leak out” from the catalysts if the material is irradiated with UV light, while substitutional nitrogen remains stable. However, the latter one was proven to be less important in the photocatalytic point of view. These observations were also valid in the case of sol-gel made nitrogen modified titanias. Furthermore, the results obtained after applying different spectroscopic methods (IR, XPS and DRS) shown that the yellow color of the titanias, does not necessary mean that a successful doping is achieved.

  9. Synthesis of Black and Red Mercury Sulfide Nano-Powder by Traditional Indian Method for Biomedical Application

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Padhi, Payodhar; Sahoo, G.; Das, K.

    The use of metals and minerals in the traditional Indian system of medicine known as aired is very common and is practiced since seventh century B.C. Metals were reduced to calcined powder form for medicinal purpose. For detoxification, a further step of purification of the metals and minerals with different vegetable extracts was practiced. The people of East India were using mercury and its sulfide as medicine. Gradually this secret was leaked to Arabic physicians who used mercury in skin ointment. Subsequently Italian Physicians adopted Arabic prescriptions of mercurial ointments for skin diseases. In the olden days, metals and mineralsmore » were impregnated with decoction and juice of vegetables and animal products like milk and fat for purification. These were then reduced to fine particles by milling with a pestle and mortar. It was known by then that the fineness of the powder had a significant influence on the color, texture, and medicinal properties as is cited by Charak. Nagarjun studied in detail the processing of metals and minerals, particularly mercury and the influence of the processing parameters on the medicinal values. Mercury is unique in many aspects. Indian alchemy developed a wide variety a chemical processes for the ostensible transmutation of metals and preparation of elixir of life, in which mercury occupied a prime position .The present investigation attempts to use the traditional methods as prescribed in the ancient texts to prepare mercury sulfide in both red and black form for medicinal use. XRD, SEM and HRTEM investigations of the sulfides obtained shows that the ancient Indians were able to produce nano-sized powders. Possibly this may be taken as the earliest application of the production and use of nano powder. The study proves that even in ancient time the knowledge of nano particle synthesis was prevalent and used to enhance effectiveness of medicines. Further mercury in the free form is not acceptable in medicines. The

  10. Synthesis of Black and Red Mercury Sulfide Nano-Powder by Traditional Indian Method for Biomedical Application

    NASA Astrophysics Data System (ADS)

    Padhi, Payodhar; Sahoo, G.; Das, K.; Ghosh, Sudipto; Panigrahi, S. C.

    2008-10-01

    The use of metals and minerals in the traditional Indian system of medicine known as aired is very common and is practiced since seventh century B.C. Metals were reduced to calcined powder form for medicinal purpose. For detoxification, a further step of purification of the metals and minerals with different vegetable extracts was practiced. The people of East India were using mercury and its sulfide as medicine. Gradually this secret was leaked to Arabic physicians who used mercury in skin ointment. Subsequently Italian Physicians adopted Arabic prescriptions of mercurial ointments for skin diseases. In the olden days, metals and minerals were impregnated with decoction and juice of vegetables and animal products like milk and fat for purification. These were then reduced to fine particles by milling with a pestle and mortar. It was known by then that the fineness of the powder had a significant influence on the color, texture, and medicinal properties as is cited by Charak. Nagarjun studied in detail the processing of metals and minerals, particularly mercury and the influence of the processing parameters on the medicinal values. Mercury is unique in many aspects. Indian alchemy developed a wide variety a chemical processes for the ostensible transmutation of metals and preparation of elixir of life, in which mercury occupied a prime position .The present investigation attempts to use the traditional methods as prescribed in the ancient texts to prepare mercury sulfide in both red and black form for medicinal use. XRD, SEM and HRTEM investigations of the sulfides obtained shows that the ancient Indians were able to produce nano-sized powders. Possibly this may be taken as the earliest application of the production and use of nano powder. The study proves that even in ancient time the knowledge of nano particle synthesis was prevalent and used to enhance effectiveness of medicines. Further mercury in the free form is not acceptable in medicines. The ancient

  11. Titania Deposition on PMR-15

    NASA Technical Reports Server (NTRS)

    Meador, Mary B.; Sutter, James K.; Pizem, Hillel; Gershevitz, Olga; Goffer, Yossi; Frimer, Aryeh A.; Sukenik, Chaim N.; Sampathkumaran, Uma; Milhet, Xavier; McIlwain, Alan

    2005-01-01

    The formation, degree of crystallinity and adherence of dense titania (TiO2) thin film coatings on a high-temperature polyimide resin (PMR-15) can be influenced by the chemical composition of the polymer surface. Furthermore, solution deposition conditions can be adjusted to provide additional control over the morphology and crystallinity of the titania films. Recipes for solution-based titania deposition that used a slowly-hydrolyzing titanium fluoride salt in the presence of boric acid as a fluoride scavenger allowed growth of films up to 750 nm thick in 22 h. By adjusting solution pH and temperature, either amorphous titania or oriented crystalline anatase films could be formed. Surface sulfonate groups enhance the adhesion of solution-deposited oxide thin film coatings. While most sulfonation procedures severely damaged the PMR-15 surface, the use of chlorosulfonic acid followed by hydrolysis of the installed chlorosulfonyl groups provided effective surface sulfonation without significant surface damage. In some cases, the oxide deposition solution caused partial hydrolysis of the polymer surface, which itself was sufficient to allow adhesion of the titania film through chelation of titanium ions by exposed benzoic acid groups on the polymer surface.

  12. Sacrificial photocatalysis: removal of nitrate and hydrogen production by nano-copper-loaded P25 titania. A kinetic and ecotoxicological assessment.

    PubMed

    Lucchetti, Roberta; Siciliano, Antonietta; Clarizia, Laura; Russo, Danilo; Di Somma, Ilaria; Di Natale, Francesco; Guida, Marco; Andreozzi, Roberto; Marotta, Raffaele

    2017-02-01

    The photocatalytic removal of nitrate with simultaneous hydrogen generation was demonstrated using zero-valent nano-copper-modified titania (P25) as photocatalyst in the presence of UV-A-Vis radiation. Glycerol, a by-product in biodiesel production, was chosen as a hole scavenger. Under the adopted experimental conditions, a nitrate removal efficiency up to 100% and a simultaneous hydrogen production up to 14 μmol/L of H 2 were achieved (catalyst load = 150 mg/L, initial concentration of nitrate = 50 mg/L, initial concentration of glycerol = 0.8 mol/L). The reaction rates were independent of the starting glycerol concentration. This process allows accomplishing nitrate removal, with the additional benefit of producing hydrogen under artificial UV-A radiation. A kinetic model was also developed and it may represent a benchmark for a detailed understanding of the process kinetics. A set of acute and chronic bioassays (Vibrio fischeri, Raphidocelis subcapitata, and Daphnia magna) was performed to evaluate the potential ecotoxicity of the nitrate/by-product mixture formed during the photocatalytic process. The ecotoxicological assessment indicated an ecotoxic effect of oxidation intermediates and by-products produced during the process.

  13. Effect of addition of Ag nano powder on mechanical properties of epoxy/polyaminoamide adduct coatings filled with conducting polymer

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Samad, Ubair Abdus; Center of excellence for research in engineering materials; Khan, Rawaiz

    In this study the effect of Ag Nano powder on mechanical properties of epoxy coatings filled with optimized ratio of conducting polymers (Polyaniline and Polyppyrole) was evaluated. Bisphenol A diglycidyl ether epoxy resin (DGEBA) along with polyaminoamide adduct (ARADUR 3282-1 BD) is used as curing agent under optimized stoichiometry values. Curing is performed at room temperature with different percentages of Nano filler. Glass and steel panels were used as coating substrate. Bird applicator was used to coat the samples in order to obtain thin film with wet film thickness (WFT) of about 70-90 µm. The samples were kept in dust freemore » environment for about 7 days at room temperature for complete curing. The coated steel panels were used to evaluate the mechanical properties of coating such as hardness, scratch and impact tests whereas coated glass panels were used for measuring pendulum hardness of the coatings. To check the dispersion and morphology of Nano filler in epoxy matrix scanning electron microscopy (SEM) was used in addition Nano indentation was also performed to observe the effect of Nano filler on modulus of elasticity and hardness at Nano scale.« less

  14. Effect of addition of Ag nano powder on mechanical properties of epoxy/polyaminoamide adduct coatings filled with conducting polymer

    NASA Astrophysics Data System (ADS)

    Samad, Ubair Abdus; Khan, Rawaiz; Alam, Mohammad Asif; Al-Othman, Othman Y.; Al-Zahrani, Saeed M.

    2015-05-01

    In this study the effect of Ag Nano powder on mechanical properties of epoxy coatings filled with optimized ratio of conducting polymers (Polyaniline and Polyppyrole) was evaluated. Bisphenol A diglycidyl ether epoxy resin (DGEBA) along with polyaminoamide adduct (ARADUR 3282-1 BD) is used as curing agent under optimized stoichiometry values. Curing is performed at room temperature with different percentages of Nano filler. Glass and steel panels were used as coating substrate. Bird applicator was used to coat the samples in order to obtain thin film with wet film thickness (WFT) of about 70-90 µm. The samples were kept in dust free environment for about 7 days at room temperature for complete curing. The coated steel panels were used to evaluate the mechanical properties of coating such as hardness, scratch and impact tests whereas coated glass panels were used for measuring pendulum hardness of the coatings. To check the dispersion and morphology of Nano filler in epoxy matrix scanning electron microscopy (SEM) was used in addition Nano indentation was also performed to observe the effect of Nano filler on modulus of elasticity and hardness at Nano scale.

  15. A study on the production of titanium carbide nano-powder in the nanostate and its properties

    NASA Astrophysics Data System (ADS)

    Shiryaeva, L. S.; Rudneva, S. V.; Galevsky, G. V.; Garbuzova, A. K.

    2016-09-01

    The plasma synthesis of titanium carbide nano-powder in the conditions close to industrial was studied. Titanium carbide TiC is a wear- and corrosion-resistant, hard, chemically inert material, demanded in various fields for the production of hard alloys, metal- ceramic tools, heat-resistant products, protective metal coatings. New perspectives for application titanium carbide in the nanostate can be found in the field of alloys modification with different composition and destination.

  16. Photocatalytic degradation of methylene blue on Sn-doped titania nanoparticles synthesized by solution combustion route

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bhange, P.D., E-mail: pallavi.ncl@gmail.com; Awate, S.V.; Gholap, R.S.

    2016-04-15

    Highlights: • Series of Sn-doped titania nanoparticles were prepared by solution combustion synthesis method. • Sn-doped titania nanoparticles were tested for degradation of MB under UV light irradiation. • The maximum Sn doping in the TiO{sub 2} lattice is found to be less than 10%. • The crystallite size decreases with increase in the Sn content. • The doping of Sn into TiO{sub 2} lattice hinders the recombination of electrons and holes thus enhance the photocatalytic activity. - Abstract: Series of tin-doped titania nanoparticles with varying tin content in the range 0–20 mol% have been prepared by solution combustion synthesismore » route using urea as a fuel. The structure, surface morphology and optical activity of Sn-doped TiO{sub 2} nanoparticles were investigated by various analytical techniques such as powder XRD, SEM, TEM, UV–vis and N{sub 2} adsorption study. The crystalline structures of the various phases were studied by rietveld refinement of the XRD data. The photocatalytic performance of Sn-doped titania nanoparticles were tested for degradation of MB under UV and visible light irradiation. The results reveal that the photocatalytic activity increases with increase in tin content which may be due to decrease in crystallite size with increase in surface area. The doping of Sn into TiO{sub 2} lattice hinders the recombination of electrons and holes thus enhance the quantum efficiency of photocatalytic reaction.« less

  17. Titania - Highest Resolution Voyager Picture

    NASA Image and Video Library

    1996-01-29

    On Jan. 24, 1986, NASA Voyager 2 returned the highest-resolution picture of Titania, Uranus largest satellite. Abundant impact craters of many sizes pockmark the ancient surface; most prominent features are fault valleys that stretch across Titania. http://photojournal.jpl.nasa.gov/catalog/PIA00039

  18. A study on flash sintering and related phenomena in titania and its composite with alumina

    NASA Astrophysics Data System (ADS)

    Shikhar

    In 2010, Cologna et. al. [1] reported that with a help of small electric field 120 Vcm-1, the sintering temperature of 3 mol % yittria stabilized zirconia could be brought down to 850°C from 1450°C. On top of reducing the temperature requirements, the green sample could be sintered from starting density of 50% to near full density in mere 5 seconds, a sintering rate three orders of magnitude higher than conventional methods. This discovery led to the emergence of a new field of enhanced sintering with electric field, named "Flash Sintering". The objective of this thesis is to understand the phenomenological behavior of flash-sintering and related phenomena on titania and its composites with alumina at elevated temperature. The possible mechanisms to explain flash sintering are discussed: Joule heating and the avalanche of defect generation [2], both induced by the rapid rise in conductivity just before the onset of the flash. Apparently, both mechanisms play a role. The thesis covers the response of pure titania and composites of titania-alumina under flash and compared with conventional sintering. We start with the sintering behavior of pure titania and observe lowering of sintering temperature requirements with higher applied electric field. The conductivity of titania during flash is also measured, and compared with the nominal conductivity of titania at equivalent temperatures. The conductivity during flash is determined to be have a different activation energy. For the composites of titania-alumina, effect of flash on the constrained sintering was studied. It is a known fact that sintering of one component of composite slows down when the other component of a different densification rate is added to it, called constrained sintering. In our case, large inclusions of alumina particles were added to nano-grained titania green compact that hindered its densification. Flash sintering was found to be overcoming this problem and near full densification was achieved

  19. Low temperature synthesis of nano alpha-alumina powder by two-step hydrolysis

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Yan, Ting; Guo, Xiaode, E-mail: guoxiaodenj@sina.com; Zhang, Xiang

    Highlights: • The nano α-Al{sub 2}O{sub 3} with good dispersion was prepared by two-step hydrolysis. • α-Al{sub 2}O{sub 3} powders were added as seed particles in the hydrolysis. • This article indicated that the glucose could impel the γ-Al{sub 2}O{sub 3} transformed to α-Al{sub 2}O{sub 3} directly. • This article indicated that the addictive of α-Al{sub 2}O{sub 3} seed could improve the phase transformation rate of γ-Al{sub 2}O{sub 3} to α-Al{sub 2}O{sub 3}. • In this article, the pure α-Al{sub 2}O{sub 3} could be obtained by calcining at 1000 °C for 1.5 h. - Abstract: The ultral fine alpha-alumina powdermore » has been successfully synthesized via two-step hydrolysis of aluminum isopropoxide. Glucose and polyvinyl pyrrolidone were used as surfactants during the appropriate processing step. The alpha-alumina powder was used as seed particles. Several synthesis parameters, such as the amount of seeds, surfactants, and calcination temperature, were studied by X-ray diffraction (XRD), Fourier transform infrared spectra (FTIR), Thermogravimetry-differential scanning calorimetry (TG-DSC), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The experimental results showed that glucose greatly lower the phase transformation temperature of alpha-alumina by impelling the gamma-alumina transformed to alpha-alumina directly, and the seed could improve the phase transformation rate of alpha-alumina, the polyvinylpyrrolidone have an effect on preventing excessive grain growth and agglomeration of alpha-alumina powder. Comparatively well dispersed alpha-alumina powder with particle size less than 50 nm can be synthesized through this method after calcinations at 1000 °C for 2 h.« less

  20. Formation and characterization of high surface area thermally stabilized titania/silica composite materials via hydrolysis of titanium(IV) tetra-isopropoxide in sols of spherical silica particles.

    PubMed

    Khalil, Kamal M S; Elsamahy, Ahmed A; Elanany, Mohamed S

    2002-05-15

    A direct synthetic route leading to titania particles dispersed on nonporous spherical silica particles has been investigated; 5, 10, and 20% (w/w) titania/silica sols mixtures were achieved via hydrolyzation of titanium tetra-isopropxide solution in the mother liquor of a freshly prepared sol of spherical silica particles (Stöber particles). Titania/silica materials were produced by subsequent drying and calcination of the xerogels so obtained for 3 h at 400 and 600 degrees C. The materials were investigated by means of thermal analyses (TGA and DSC), FT-IR, N(2) gas adsorption-desorption, powder X-ray diffraction (XRD), and transmission electron microscopy (TEM). In spite of the low surface area (13.1 m(2)/g) of the pure spherical silica particles calcined at 400 degrees C, high surface area and mesoporous texture titania/silica materials were obtained (e.g., S(BET) ca. 293 m(2)/g for the 10% titania/silica calcined at 400 degrees C). Moreover, the materials were shown to be amorphous toward XRD up to 600 degrees C, while reasonable surface areas were preserved. It has been concluded that dispersion of titania particles onto the surface of the nonporous spherical silica particles increase their roughness, therefore leading to composite materials of less firm packing and mesoporosity.

  1. Development of highly porous crystalline titania photocatalysts

    NASA Astrophysics Data System (ADS)

    Marszewski, Michal

    The objectives of this dissertation are the design, synthesis, and characterization of titania materials with surface area, porosity, crystallinity and doping tailored toward photocatalytic applications. Ultimately, the research should result in a strategy allowing the synthesis of titania with all these important features. The synthetic methods investigated in this research will include: i) soft-templating, ii) hard-templating, and iii) modified precursor strategy. Soft-templating strategy uses organic templates--either block copolymers or surfactants--that under specific conditions assemble into micelles, and later, these micelles are used to template the desired material around them. The resulting organic-inorganic composite is then calcined in air to remove the organic template and recover the final material with high surface area and large pore volume. This work explores 1) synthesis of titania materials in the presence of polymer templates, and the effects of different synthetic conditions on the structure of the resulting materials. Hard-templating, in contrast to soft-templating, uses inorganic templates. The hard template is introduced during the synthesis to cast its shape onto the fabricated material and removed afterwards, when the material has formed. The final material is an inverse replica of the hard template used, typically with a well-developed mesostructure. This work explores 1) hard templating synthesis of titania materials using silica and alumina, and 2) the effects of the template amount and type. The modified precursor strategy is a novel synthetic method, developed in this research, and designed specifically to achieve titania material with high surface area, large pore volume, high crystallinity, and possibly doping. The modified precursors are prepared by reacting generic titania precursors, such as titanium isopropoxide (TIPO), with organic acids, which results in substitution of some or all alkoxide groups in TIPO structure. The goal

  2. Synthesis of Nano-Size AlN Powders by Carbothermal Reduction from Plasma-Assisted Ball Milling Precursor

    NASA Astrophysics Data System (ADS)

    Liu, Zhijie; Wang, Wenchun; Yang, Dezheng; Wang, Sen; Dai, Leyang

    2016-07-01

    Nano-size aluminum nitride (AlN) powders have been successfully synthesized with a high efficiency method through annealing from milling assisted by discharge plasma (p-milling) alumina (Al2O3) precursors. The characterization of the p-milling Al2O3 powders and the synthesized AlN are investigated. Compared to conventional ball milling (c-milling), it can be found that the precursors by p-milling have a finer grain size with a higher specific surface area, which lead to a faster reaction efficiency and higher conversion to AlN at lower temperatures. The activation energy of p-milling Al2O3 is found to be 371.5 kJ/mol, a value that is much less than the reported value of the unmilled and the conventional milled Al2O3. Meanwhile, the synthesized AlN powders have unique features, such as an irregular lamp-like morphology with uniform particle distribution and fine average particle size. The results are attributed to the unique synergistic effect of p-milling, which is the effect of deformation, fracture, and cold welding of Al2O3 powders resulting from ball milling, that will be enhanced due to the introduction of discharge plasma. supported by National Natural Science Foundation of China (No. 51177008)

  3. Anti-flammable vinyl ester resin nano-composite with nano-titania

    NASA Astrophysics Data System (ADS)

    Das, Rajib

    Anti-flammable material is a common expectation for any industry and household applications to protect the material from fire accident. Polymer composites also play a significant role in preparing anti flammable materials. Vinyl ester resins (VERs) are thermosetting resins that have excellent mechanical and thermal properties of epoxy resins and Nanotitania is an inexpensive, nontoxic and biocompatible inorganic material. In this paper to investigate the flame retardency of polymer nanocomposites VER is used as polymer matrix and TiO2 is used as inorganic nanofiller.3-[2-(2-aminoethylamino) ethylamino]propyl-trimethoxysilane (TATMS), a kind of silane is used as a coupling agent to functionalize the surface of nanoTiO2 to improve its flame retardency by adding Si and N2 group. TGA test and FTIR test have been performed and different peaks for Si and N2 in the modified nanofiller and weight loss of fabricated nanofiller confirmed that fabrication method was successful. After that, nanocomposite sample of VERs reinforced with nano TiO2 prepared and the effects of different loadings on mechanical and flame retardant properties are investigated after and before the modification of nanofillers. From tensile test result it is found that up to 5% loading of modified nanofiller the tensile strength is 62 MPa that is almost as same as pure VER and the tensile strength of unmodified nanofiller based PNC is 68 MPa which is not significant improvement in its mechanical property. From MCC test of flame retardancy it is found that the normalized heat release capacity of modified nanofiller based nanocomposite is decreased by 27.7% than unmodified nanofiller based PNC that is 9.8%. Also the normalized total heat release of modified nanofiller based PNC is 21.4% than unmodified PNC that is 12.4%.

  4. [Study on nano-CaCO3 applicated in Xin Yue Shu Capsules preliminarily].

    PubMed

    Jiang, Yan-Rong; Zhang, Zhen-Hai; Cui, Li; He, Jun-Jie; Hu, Shao-Ying; Jia, Xiao-Bin

    2012-11-01

    To investigate the characteristics of nano-CaCO3 applicated in Xin Yue Shu Capsules. Studied the effect of different dosages of aerosil or nano-CaCO3 on fluidity, bulk density, moisture absorption of Xin Yue Shu capsules spray drying powder. In vitro dissolution and ferulic acid stability of Xin Yue Shu capsules was observed. It significantly improved powder fluidity and bulk density of Xin Yue Shu spray drying powder when aerosil or nano-CaCO3 was added. But there was no significant effect on powder moisture absorption, ferulic acid in vitro dissolution and ferulic acid stability. The effect of Nano-CaCO3 on improving powder fluidity and bulk density applicated in the spray drying powder of traditional Chinese medicine deserves studying further.

  5. Spheroidization of glass powders for glass ionomer cements.

    PubMed

    Gu, Y W; Yap, A U J; Cheang, P; Kumar, R

    2004-08-01

    Commercial angular glass powders were spheroidized using both the flame spraying and inductively coupled radio frequency plasma spraying techniques. Spherical powders with different particle size distributions were obtained after spheroidization. The effects of spherical glass powders on the mechanical properties of glass ionomer cements (GICs) were investigated. Results showed that the particle size distribution of the glass powders had a significant influence on the mechanical properties of GICs. Powders with a bimodal particle size distribution ensured a high packing density of glass ionomer cements, giving relatively high mechanical properties of GICs. GICs prepared by flame-spheroidized powders showed low strength values due to the loss of fine particles during flame spraying, leading to a low packing density and few metal ions reacting with polyacrylic acid to form cross-linking. GICs prepared by the nano-sized powders showed low strength because of the low bulk density of the nano-sized powders and hence low powder/liquid ratio of GICs.

  6. Effect of annealing temperature on titania nanoparticles

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Manikandan, K., E-mail: sanjaymani367@gmail.com; Arumugam, S., E-mail: sanjaymani367@gmail.com; Chandrasekaran, G.

    2014-04-24

    Titania polycrystalline samples are prepared by using sol-gel route hydrolyzing a alkoxide titanium precursor under acidic conditions. The as prepared samples are treated with different calcination temperatures. The anatase phase of titania forms when treated below 600°C, above that temperature the anatase phase tends to transform into the rutile phase of titania. The experimental determination of average grain size, phase formation, lattice parameters and the crystal structures of titania samples at different calcinations is done using X-ray diffraction (XRD). Fourier Transform Infra-red Spectroscopy (FTIR), UV-vis-NIR spectroscopy and Scanning Electron Microscopy (SEM) and Energy Dispersive Analysis X-ray are used to characterizemore » the samples to bring impact on the respective properties.« less

  7. Preparation of proton conducting membranes containing bifunctional titania nanoparticles

    NASA Astrophysics Data System (ADS)

    Aslan, Ayşe; Bozkurt, Ayhan

    2013-07-01

    Throughout this work, the synthesis and characterization of novel proton conducting nanocomposite membranes including binary and ternary mixtures of sulfated nano-titania (TS), poly(vinyl alcohol) (PVA), and nitrilotri(methyl phosphonic acid) (NMPA) are discussed. The materials were produced by means of two different approaches where in the first, PVA and TS (10-15 nm) were admixed to form a binary system. The second method was the ternary nanocomposite membranes including PVA/TS/NMPA that were prepared at several compositions to get PVA-TS-(NMPA) x . The interaction of functional nano particles and NMPA in the host matrix was explored by FT-IR spectroscopy. The homogeneous distribution of bifunctional nanoparticles in the membrane was confirmed by SEM micrographs. The spectroscopic measurements and water/methanol uptake studies suggested a complexation between PVA and NMPA, which inhibited the leaching of the latter. The thermogravimetry analysis results verified that the presence of TS in the composite membranes suppressed the formation of phosphonic acid anhydrides up to 150 °C. The maximum proton conductivity has been measured for PVA-TS-(NMPA)3 as 0.003 S cm-1 at 150 °C.

  8. Influence of calcinated and non calcinated nanobioglass particles on hardness and bioactivity of sol-gel-derived TiO2-SiO2 nano composite coatings on stainless steel substrates.

    PubMed

    Dadash, Mohammad Saleh; Karbasi, Saeed; Esfahani, Mojtaba Nasr; Ebrahimi, Mohammad Reza; Vali, Hojatollah

    2011-04-01

    Thick films of calcinated and non calcinated nanobioglass (NBG)-titania composite coatings were prepared on stainless steel substrates by alkoxide sol-gel process. Dip-coating method was used for the films preparation. The morphology, structure and composition of the nano composite films were evaluated using environmental scanning electron microscope, X-ray diffraction and Fourier transform infrared spectroscope. The SEM investigation results showed that prepared thick NBG-titania films are smooth and free of macrocracking, fracture or flaking. The grain size of these films was uniform and nano scale (50-60 nm) which confirmed with TEM. Also FTIR confirmed the presence of Si-O-Si bands on the calcinated NBG-titania films. The hardness of the prepared films (TiO(2)-calcinated NBG and TiO(2)-Non calcinated NBG) was compared by using micro hardness test method. The results verified that the presence of calcinated NBG particles in NBG-titania composite enhanced gradually the mechanical data of the prepared films. The in vitro bioactivity of these films was discussed based on the analysis of the variations of Ca and P concentrations in the simulated body fluid (SBF) and their surface morphologies against immersion time. Surface morphology and Si-O-Si bands were found to be of great importance with respect to the bioactivity of the studied films. The results showed that calcinated NBG-titania films have better bioactivity than non calcinated NBG-titania films.

  9. Novel hydrothermal method for effective doping of N and F into nano Titania for both, energy and environmental applications

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jyothi, M.S.; D’Souza Laveena, P.; Shwetharani, R.

    2016-02-15

    Highlights: • Novel method to synthesize N, F doped TiO{sub 2} via hydrothermal method is discussed. • Change in bandgap of TiO{sub 2} upon doping makes a photocatalyst visible active. • 94% of degradation of EtBr was achieved within a less time of 90 min. • The doped titania also showed good efficiency as photo anodic material for solar cell. - Abstract: A novel and an efficient hydrothermal method for the preparation of an effective doped titania photocatalyst is reported. The crystal phase, binding energy, elemental composition, morphology, optical and electronic structure analyses were done by various techniques. The dopedmore » titania proved as an efficient electrode material and photocatalyst for solar cells and water treatment respectively. The photocatalyst is able to degrade the most potent mutagen ethidium bromide under sunlight with an enhancement of 1.6 times over its undoped analogue. As photo-anode material, showed an improved open circuit potential and fill factor. The created electron states in the doped sample act as charge carrier traps suppressing recombination which later detraps the same to the surface of the catalyst causing enhanced interfacial charge transfer. Surface acidity caused by F induction and lowered band gap energy that can respond to visible light facilitates improved energy harvesting and energy transfer leading to better photo activity.« less

  10. Environmentally benign Friedel-Crafts benzylation over nano-TiO2/SO4 2-

    NASA Astrophysics Data System (ADS)

    Devi, Kalathiparambil RPS; Sreeja, Puthenveetil B.; Sugunan, Sankaran

    2013-05-01

    During the past decade, much attention has been paid to the replacement of homogeneous catalysts by solid acid catalysts. Friedel-Crafts benzylation of toluene with benzyl chloride (BC) in liquid phase was carried out over highly active, nano-crystalline sulfated titania systems. These catalysts were prepared using the sol gel method. Modification was done by loading 3% of transition metal oxides over sulfated titania. Reaction parameters such as catalyst mass, molar ratio, temperature, and time have been studied. More than 80% conversion of benzyl chloride and 100% selectivity are shown by all the catalysts under optimum conditions. Catalytic activity is correlated with Lewis acidity obtained from perylene adsorption studies. The reaction appears to proceed by an electrophile, which involves the reaction of BC with the acidic titania catalyst. The catalyst was regenerated and reused up to four reaction cycles with equal efficiency as in the first run. The prepared systems are environmentally friendly and are easy to handle.

  11. Photocatalytic activity of titania coatings synthesised by a combined laser/sol–gel technique

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Adraider, Y.; Pang, Y.X., E-mail: F6098038@tees.ac.uk; Nabhani, F.

    2014-06-01

    Highlights: • Sol–gel method was used to prepare titania coatings. • Titania thin films were coated on substrate surface by dip coating. • Fibre laser was employed to irradiate the titania coated surfaces. • Photocatalytic efficiency of titania coatings was significantly improved after laser processing. - Abstract: Titania coatings were prepared using sol–gel method and then applied on the substrate surface by dip coating. Fibre laser (λ = 1064 nm) in continuous wave mode was used to irradiate the titania coated surfaces at different specific energies. The ATR-FTIR, XRD, SEM, EDS and contact angle measurement were employed to analyse surfacemore » morphology, phase composition and crystalline structure of laser-irradiated titania coatings, whilst the photocatalytic activity was evaluated by measuring the decomposition of methylene blue (MB) after exposure to the visible light for various illumination times. Results showed that the laser-irradiated titania coatings demonstrate significant different composition and microstructure in comparison with the as-coated from the same sol–gel titania. Photocatalytic efficiency of titania coatings was significantly improved after laser processing. The photocatalytic activity of laser-irradiated titania coatings was higher than that of the as-coated titania. The titania coating processed at laser specific energy of 6.5 J/mm{sup 2} exhibited the highest photocatalytic activity among all titania samples.« less

  12. Synthesis and LPG sensing properties of nano-sized cadmium oxide.

    PubMed

    Waghulade, R B; Patil, P P; Pasricha, Renu

    2007-04-30

    This paper reports the synthesis and liquid petroleum gas (LPG) sensing properties of nano-sized cadmium oxide (CdO). The nano-sized CdO powder was successfully synthesized by using a chemical co-precipitation method using cadmium acetate and the ammonium hydroxide, as starting materials and water as a carrier. The resulting nano-sized powder was characterized by X-ray diffraction (XRD) measurements and the transmission electron microscopy (TEM). The LPG sensing properties of the synthesized nano-sized CdO were investigated at different operating temperatures and LPG concentrations. It was found that the calcination temperature and the operating temperature significantly affect the sensitivity of the nano-sized CdO powder to the LPG. The sensitivity is found to be maximum when the calcination temperature was 400 degrees C. The sensitivity to 75ppm of LPG is maximum at an operating temperature 450 degrees C and it was found to be approximately 341%. The response and recovery times were found to be nearly 3-5s and 8-10s, respectively. The synthesized nano-sized CdO powder is able to detect up to 25ppm for LPG with reasonable sensitivity at an operating temperature 450 degrees C and it can be reliably used to monitor the concentration of LPG over the range (25-75ppm). The experimental results of the LPG sensing studies reveal that the nano-sized CdO powder synthesized by a simple co-precipitation method is a suitable material for the fabrication of the LPG sensor.

  13. Preparation, Characterization, and Enhanced Thermal and Mechanical Properties of Epoxy-Titania Composites

    PubMed Central

    Rubab, Zakya; Siddiqi, Humaira M.; Saeed, Shaukat

    2014-01-01

    This paper presents the synthesis and thermal and mechanical properties of epoxy-titania composites. First, submicron titania particles are prepared via surfactant-free sol-gel method using TiCl4 as precursor. These particles are subsequently used as inorganic fillers (or reinforcement) for thermally cured epoxy polymers. Epoxy-titania composites are prepared via mechanical mixing of titania particles with liquid epoxy resin and subsequently curing the mixture with an aliphatic diamine. The amount of titania particles integrated into epoxy matrix is varied between 2.5 and 10.0 wt.% to investigate the effect of sub-micron titania particles on thermal and mechanical properties of epoxy-titania composites. These composites are characterized by X-ray photoelectron (XPS) spectroscopy, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric (TG), and mechanical analyses. It is found that sub-micron titania particles significantly enhance the glass transition temperature (>6.7%), thermal oxidative stability (>12.0%), tensile strength (>21.8%), and Young's modulus (>16.8%) of epoxy polymers. Epoxy-titania composites with 5.0 wt.% sub-micron titania particles perform best at elevated temperatures as well as under high stress. PMID:24578638

  14. Extremely fine structured cathode for solid oxide fuel cells using Sr-doped LaMnO3 and Y2O3-stabilized ZrO2 nano-composite powder synthesized by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Shimada, Hiroyuki; Yamaguchi, Toshiaki; Sumi, Hirofumi; Nomura, Katsuhiro; Yamaguchi, Yuki; Fujishiro, Yoshinobu

    2017-02-01

    A solid oxide fuel cell (SOFC) for high power density operation was developed with a microstructure-controlled cathode using a nano-composite powder of Sr-doped LaMnO3 (LSM) and Y2O3-stabilized ZrO2 (YSZ) synthesized by spray pyrolysis. The individual LSM-YSZ nano-composite particles, formed by crystalline and amorphous nano-size LSM and YSZ particles, showed spherical morphology with uniform particle size. The use of this powder for cathode material led to an extremely fine microstructure, in which all the LSM and YSZ grains (approximately 100-200 nm) were highly dispersed and formed their own network structures. This microstructure was due to the two phase electrode structure control using the powder, namely, nano-order level in each particle and micro-order level between particles. An anode-supported SOFC with the LSM-YSZ cathode using humidified H2 as fuel and ambient air as oxidant exhibited high power densities, such as 1.29 W cm-2 under a voltage of 0.75 V and a maximum power density of 2.65 W cm-2 at 800 °C. Also, the SOFC could be stably operated for 250 h with no degradation, even at a high temperature of 800 °C.

  15. Nano spray drying for encapsulation of pharmaceuticals.

    PubMed

    Arpagaus, Cordin; Collenberg, Andreas; Rütti, David; Assadpour, Elham; Jafari, Seid Mahdi

    2018-05-17

    Many pharmaceuticals such as pills, capsules, or tablets are prepared in a dried and powdered form. In this field, spray drying plays a critical role to convert liquid pharmaceutical formulations into powders. In addition, in many cases it is necessary to encapsulate bioactive drugs into wall materials to protect them against harsh process and environmental conditions, as well as to deliver the drug to the right place and at the correct time within the body. Thus, spray drying is a common process used for encapsulation of pharmaceuticals. In view of the rapid progress of nanoencapsulation techniques in pharmaceutics, nano spray drying is used to improve drug formulation and delivery. The nano spray dryer developed in the recent years provides ultrafine powders at nanoscale and high product yields. In this paper, after explaining the concept of nano spray drying and understanding the key elements of the equipment, the influence of the process parameters on the final powders properties, like particle size, morphology, encapsulation efficiency, drug loading and release, will be discussed. Then, numerous application examples are reviewed for nano spray drying and encapsulation of various drugs in the early stages of product development along with a brief overview of the obtained results and characterization techniques. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. NanoClusters Enhance Drug Delivery in Mechanical Ventilation

    NASA Astrophysics Data System (ADS)

    Pornputtapitak, Warangkana

    The overall goal of this thesis was to develop a dry powder delivery system for patients on mechanical ventilation. The studies were divided into two parts: the formulation development and the device design. The pulmonary system is an attractive route for drug delivery since the lungs have a large accessible surface area for treatment or drug absorption. For ventilated patients, inhaled drugs have to successfully navigate ventilator tubing and an endotracheal tube. Agglomerates of drug nanoparticles (also known as 'NanoClusters') are fine dry powder aerosols that were hypothesized to enable drug delivery through ventilator circuits. This Thesis systematically investigated formulations of NanoClusters and their aerosol performance in a conventional inhaler and a device designed for use during mechanical ventilation. These engineered powders of budesonide (NC-Bud) were delivered via a MonodoseRTM inhaler or a novel device through commercial endotracheal tubes, and analyzed by cascade impaction. NC-Bud had a higher efficiency of aerosol delivery compared to micronized stock budesonide. The delivery efficiency was independent of ventilator parameters such as inspiration patterns, inspiration volumes, and inspiration flow rates. A novel device designed to fit directly to the ventilator and endotracheal tubing connections and the MonodoseRTM inhaler showed the same efficiency of drug delivery. The new device combined with NanoCluster formulation technology, therefore, allowed convenient and efficient drug delivery through endotracheal tubes. Furthermore, itraconazole (ITZ), a triazole antifungal agent, was formulated as a NanoCluster powder via milling (top-down process) or precipitation (bottom-up process) without using any excipients. ITZ NanoClusters prepared by wet milling showed better aerosol performance compared to micronized stock ITZ and ITZ NanoClusters prepared by precipitation. ITZ NanoClusters prepared by precipitation methods also showed an amorphous state

  17. Synthesis of Nano-Crystalline Gamma-TiAl Materials

    NASA Technical Reports Server (NTRS)

    Hales, Stephen J.; Vasquez, Peter

    2003-01-01

    One of the principal problems with nano-crystalline materials is producing them in quantities and sizes large enough for valid mechanical property evaluation. The purpose of this study was to explore an innovative method for producing nano-crystalline gamma-TiAl bulk materials using high energy ball milling and brief secondary processes. Nano-crystalline powder feedstock was produced using a Fritsch P4(TM) vario-planetary ball mill recently installed at NASA-LaRC. The high energy ball milling process employed tungsten carbide tooling (vials and balls) and no process control agents to minimize contamination. In a collaborative effort, two approaches were investigated, namely mechanical alloying of elemental powders and attrition milling of pre-alloyed powders. The objective was to subsequently use RF plasma spray deposition and short cycle vacuum hot pressing in order to effect consolidation while retaining nano-crystalline structure in bulk material. Results and discussion of the work performed to date are presented.

  18. Recent progress in mesoporous titania materials: adjusting morphology for innovative applications.

    PubMed

    Vivero-Escoto, Juan L; Chiang, Ya-Dong; Wu, Kevin; Yamauchi, Yusuke

    2012-02-01

    This review article summarizes recent developments in mesoporous titania materials, particularly in the fields of morphology control and applications. We first briefly introduce the history of mesoporous titania materials and then review several synthesis approaches. Currently, mesoporous titania nanoparticles (MTNs) have attracted much attention in various fields, such as medicine, catalysis, separation and optics. Compared with bulk mesoporous titania materials, which are above a micrometer in size, nanometer-sized MTNs have additional properties, such as fast mass transport, strong adhesion to substrates and good dispersion in solution. However, it has generally been known that the successful synthesis of MTNs is very difficult owing to the rapid hydrolysis of titanium-containing precursors and the crystallization of titania upon thermal treatment. Finally, we review four emerging fields including photocatalysis, photovoltaic devices, sensing and biomedical applications of mesoporous titania materials. Because of its high surface area, controlled porous structure, suitable morphology and semiconducting behavior, mesoporous titania is expected to be used in innovative applications.

  19. Formation and photopatterning of nanoporous titania thin films

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Park, Oun-Ho; Cheng, Joy Y.; Kim, Hyun Suk

    2007-06-04

    Photopatternable nanoporous titania thin films were generated from mixtures of an organic diblock copolymer, poly(styrene-b-ethylene oxide) (PS-b-PEO), and an oligomeric titanate (OT) prepared from a chelated titanium isopropoxide. The PS-b-PEO templates well-defined microdomains in thin films of the mixtures, which upon thermal treatment at 450 deg. C, become nanopores in titania. Average pore size and porosity are controlled by the molecular weight and loading level of the PS-b-PEO, respectively. Patterns of nanoporous titania were created by selectively exposing UV light on the mixture films. The UV irradiation destroys the chelating bond and induces the cross-linking reaction of the OT. Subsequentmore » wet development followed by thermal treatment gives patterned nanoporous films of anatase phase titania.« less

  20. Cobalt and sulfur co-doped nano-size TiO2 for photodegradation of various dyes and phenol.

    PubMed

    Siddiqa, Asima; Masih, Dilshad; Anjum, Dalaver; Siddiq, Muhammad

    2015-11-01

    Various compositions of cobalt and sulfur co-doped titania nano-photocatalyst are synthesized via sol-gel method. A number of techniques including X-ray diffraction (XRD), ultraviolet-visible (UV-Vis), Rutherford backscattering spectrometry (RBS), thermal gravimetric analysis (TGA), Raman, N2 sorption, electron microscopy are used to examine composition, crystalline phase, morphology, distribution of dopants, surface area and optical properties of synthesized materials. The synthesized materials consisted of quasispherical nanoparticles of anatase phase exhibiting a high surface area and homogeneous distribution of dopants. Cobalt and sulfur co-doped titania demonstrated remarkable structural and optical properties leading to an efficient photocatalytic activity for degradation of dyes and phenol under visible light irradiations. Moreover, the effect of dye concentration, catalyst dose and pH on photodegradation behavior of environmental pollutants and recyclability of the catalyst is also examined to optimize the activity of nano-photocatalyst and gain a better understanding of the process. Copyright © 2015. Published by Elsevier B.V.

  1. Lightweight Aluminum/Nano composites for Automotive Drive Train Applications

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chelluri, Bhanumathi; Knoth, Edward A.; Schumaker, Edward J.

    2012-12-14

    During Phase I, we successfully processed air atomized aluminum powders via Dynamic Magnetic Compaction (DMC) pressing and subsequent sintering to produce parts with properties similar to wrought aluminum. We have also showed for the first time that aluminum powders can be processed without lubes via press and sintering to 100 % density. This will preclude a delube cycle in sintering and promote environmentally friendly P/M processing. Processing aluminum powders via press and sintering with minimum shrinkage will enable net shape fabrication. Aluminum powders processed via a conventional powder metallurgy process produce too large a shrinkage. Because of this, sinter partsmore » have to be machined into specific net shape. This results in increased scrap and cost. Fully sintered aluminum alloy under this Phase I project has shown good particle-to-particle bonding and mechanical properties. We have also shown the feasibility of preparing nano composite powders and processing via pressing and sintering. This was accomplished by dispersing nano silicon carbide (SiC) powders into aluminum matrix comprising micron-sized powders (<100 microns) using a proprietary process. These composite powders of Al with nano SiC were processed using DMC press and sinter process to sinter density of 85-90%. The process optimization along with sintering needs to be carried out to produce full density composites.« less

  2. Novel multifunctional titania-silica-lanthanum phosphate nanocomposite coatings through an all aqueous sol-gel process.

    PubMed

    Smitha, Venu Sreekala; Jyothi, Chembolli Kunhatta; Peer, Mohamed A; Pillai, Saju; Warrier, Krishna Gopakumar

    2013-04-07

    A novel nanocomposite coating containing titania, silica and lanthanum phosphate prepared through an all aqueous sol-gel route exhibits excellent self-cleaning ability arising from the synergistic effect of the constituents in the nanocomposite. A highly stable titania-silica-lanthanum phosphate nanocomposite sol having particle size in the range of 30-50 nm has been synthesized starting from a titanyl sulphate precursor, which was further used for the development of photocatalytically active composite coatings on glass. The coatings prepared by the dip coating technique as well as the nanocomposite powders are heat treated and characterized further for their morphology and multifunctionality. The nanocomposite containing 1.5 wt% LaPO4 has shown a surface area as high as 138 m(2) g(-1) and a methylene blue degradation efficiency of 94% in two hours of UV exposure. The composite coating has shown very good homogeneity evidenced by transparency as high as 99.5% and low wetting behaviour. The present novel approach for energy conserving, aqueous derived, self-cleaning coatings may be suitable for large scale industrial applications.

  3. Effect of titania content and biomimetic coating on the mechanical properties of the Y-TZP/TiO2 composite.

    PubMed

    Miranda, Ranulfo Benedito de Paula; Miranda, Walter Gomes; Lazar, Dolores Ribeiro Ricci; Ussui, Valter; Marchi, Juliana; Cesar, Paulo Francisco

    2018-02-01

    To investigate the effect of titania addition (0, 10 and 30mol%) on the microstructure, relative density, Young's modulus (E), Poisson's ratio (υ), mechanical properties (flexural strength, σ f , and Weibull modulus, m) of a Y-TZP/TiO 2 composite. The effect of the presence of a biomimetic coating on the microstructure and mechanical properties was also evaluated. Y-TZP (3mol% of yttria) and Y-TZP/TiO 2 composite (10 or 30mol% of titania) were synthesized by co-precipitation. The powders were pressed and sintered at 1400°C/2h. The surfaces, with and without biomimetic coating, were characterized by X-ray diffraction analysis and scanning electron microscopy. The relative density was measured by the Archimedes' principle. E and υ were measured by ultrasonic pulse-echo method. For the mechanical properties the specimens (n=30 for each group) were tested in a universal testing machine. Titania addition increased the grain size of the composite and caused a significant decrease in the flexural strength (in MPa, control 815.4 a ; T10 455.7 b and T30 336.0 c ), E (in GPa, control 213.4 a ; T10 155.8 b and T30 134.0 c ) and relative density (control 99.0% a ; T10 94.4% c and T30 96.3% b ) of the Y-TZP/TiO 2 composite. The presence of 30% titania caused substantial increase in m and υ. Biomimetic coating did not affect the mechanical properties of the composite. The Y-TZP/TiO 2 composite coated with a layer of CaP has great potential to be used as implant material. Although addition of titania affected the properties of the composite, the application of a biomimetic coating did not jeopardize its reliability. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  4. 40 CFR 721.9680 - Alkaline titania silica gel (generic name).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Alkaline titania silica gel (generic... Specific Chemical Substances § 721.9680 Alkaline titania silica gel (generic name). (a) Chemical substance... alkaline titania silica gel (PMN P-95-529) is subject to reporting under this section for the significant...

  5. 40 CFR 721.9680 - Alkaline titania silica gel (generic name).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alkaline titania silica gel (generic... Specific Chemical Substances § 721.9680 Alkaline titania silica gel (generic name). (a) Chemical substance... alkaline titania silica gel (PMN P-95-529) is subject to reporting under this section for the significant...

  6. 40 CFR 721.9680 - Alkaline titania silica gel (generic name).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Alkaline titania silica gel (generic... Specific Chemical Substances § 721.9680 Alkaline titania silica gel (generic name). (a) Chemical substance... alkaline titania silica gel (PMN P-95-529) is subject to reporting under this section for the significant...

  7. 40 CFR 721.9680 - Alkaline titania silica gel (generic name).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkaline titania silica gel (generic... Specific Chemical Substances § 721.9680 Alkaline titania silica gel (generic name). (a) Chemical substance... alkaline titania silica gel (PMN P-95-529) is subject to reporting under this section for the significant...

  8. 40 CFR 721.9680 - Alkaline titania silica gel (generic name).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Alkaline titania silica gel (generic... Specific Chemical Substances § 721.9680 Alkaline titania silica gel (generic name). (a) Chemical substance... alkaline titania silica gel (PMN P-95-529) is subject to reporting under this section for the significant...

  9. Reinforcement of acrylic resins for provisional fixed restorations. Part III: effects of addition of titania and zirconia mixtures on some mechanical and physical properties.

    PubMed

    Panyayong, W; Oshida, Y; Andres, C J; Barco, T M; Brown, D T; Hovijitra, S

    2002-01-01

    Acrylic resins have been used in many different applications in dentistry, especially in the fabrication of provisional fixed partial dentures. Ideally, a provisional crown and bridge material should be easy to handle and should protect teeth against physical, chemical, and thermal injuries. Some of the problems associated with this use are related to the material's poor mechanical properties. It has been demonstrated that acrylic resin can be strengthened through the addition of structural component of different size distributed in the acrylic matrix, thus forming a composite structure. The purpose of this study was to investigate the addition effects of mixtures of titania (titanium dioxide, TiO(2)) powder and zirconia (zirconium dioxide, ZrO(2)) powder being incorporated with pre-polymerized beads mixed in monomer liquid, on some mechanical and physical properties of PMMA resin. The pre-polymerized powder poly(methyl methacrylate) resin was admixed with titania and zirconia powder. A mixing ratio was controlled by volume % of 0, 1.0, 2.0, and 3.0 (samples with 0 v/o served as control groups). For using mixture of titania and zirconia, total amount of the mixture was controlled by volume % of 1.0, 2.0, and 3.0, in which titania and zirconia were mixed at the ratio 1 :1, 1 :2 and 2 :1. Prior to mechanical tests, all rectangular-shaped samples (25 mm x 2 mm x 5 mm) were stored in 37 degrees C distilled water for 7 days after polishing all six sides of samples. Samples were then subjected to the three-point bending flexion test to evaluate the bending strength as well as the modulus of elasticity. Weight gain and exothermic reaction survey were investigated as well. All data were collected and analyzed with one-way analysis of variance (ANOVA) and Sidak method (p=0.05). It was found that the addition of particles generally decreased the water absorbed by the composite system. Only 1 percent by volume concentration of 1 :1 ratio and 2 percent by volume concentration

  10. Entrapment of Bacteriocin 105B onto Fabric with Titania

    DTIC Science & Technology

    2017-02-09

    to fabricate a multifunctional textile exhibiting an alternative range of antimicrobial activity from that of nisin, by titania encapsulation of...105b onto fabric. The results of these initial studies suggest that both pure preparations and semi-pure preparations of 105b are active when...encapsulated in titania in solution. However, when the pure preparation of 105b is titania encapsulated on fabric, antimicrobial activity is not observed

  11. Synthesis and energy applications of mesoporous titania thin films

    NASA Astrophysics Data System (ADS)

    Islam, Syed Z.

    The optical and electronic properties of TiO2 thin films provide tremendous opportunities in several applications including photocatalysis, photovoltaics and photoconductors for energy production. Despite many attractive features of TiO2, critical challenges include the innate inability of TiO2 to absorb visible light and the fast recombination of photoexcited charge carriers. In this study, mesoporous TiO2 thin films are modified by doping using hydrogen and nitrogen, and sensitization using graphene quantum dot sensitization. For all of these modifiers, well-ordered mesoporous titania films were synthesized by surfactant templated sol-gel process. Two methods: hydrazine and plasma treatments have been developed for nitrogen and hydrogen doping in the mesoporous titania films for band gap reduction, visible light absorption and enhancement of photocatalytic activity. The hydrazine treatment in mesoporous titania thin films suggests that hydrazine induced doping is a promising approach to enable synergistic incorporation of N and Ti3+ into the lattice of surfactant-templated TiO2 films and enhanced visible light photoactivity, but that the benefits are limited by gradual mesostructure deterioration. The plasma treated nitrogen doped mesoporous titania showed about 240 times higher photoactivity compared to undoped film in hydrogen production from photoelectrochemical water splitting under visible light illumination. Plasma treated hydrogen doped mesoporous titania thin films has also been developed for enhancement of visible light absorption. Hydrogen treatment has been shown to turn titania (normally bright white) black, indicating vastly improved visible light absorption. The cause of the color change and its effectiveness for photocatalysis remain open questions. For the first time, we showed that a significant amount of hydrogen is incorporated in hydrogen plasma treated mesoporous titania films by neutron reflectometry measurements. In addition to the

  12. Non-stoichiometric mixed-phase titania photocatalyst

    DOEpatents

    Chen, Le [Lakewood, CO; Gray, Kimberly A [Evanston, IL; Graham, Michael E [Evanston, IL

    2012-06-19

    A mixed anatase-rutile phase, non-stoichiometric titania photocatalyst material is a highly reactive and is a UV and visible light responsive photocastalyst in the as-deposited condition (i.e. without the need for a subsequent thermal treatment). The mixed phase, non-stoichiometric titania thin film material is non-stoichiometric in terms of its oxygen content such that the thin film material shows a marked red-shift in photoresponse.

  13. Influence of attrition milling on nano-grain boundaries

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Rawers, J.; Cook, D.

    1999-03-01

    Nanostructured materials have a relatively large proportion of their atoms associated with the grain boundary, and the method used to develop the nano-grains has a strong influence on the resulting grain boundary structure. In this study, attrition milling iron powders and blends of iron powders produced micron-size particles composed of nano-size grains. Mechanical cold-working powder resulted in dislocation generation, multiplication, and congealing that produced grain refinement. As the grain size approached nano-dimensions, dislocations were no longer sustained within the grain and once generated, rapidly diffused to the grain boundary. Dislocations on the grain boundary strained the local lattice structure which,more » as the grain size decreased, became the entire grain. Mechanical alloying of substitutional aluminium atoms into iron powder resulted in the aluminium atoms substituting for iron atoms in the grain boundary cells and providing a grain boundary structure similar to that of the iron powder processed in argon. Attrition milling iron powder in nitrogen gas resulted in nitrogen atoms being adsorbed onto the particle surface. Continued mechanical milling infused the nitrogen atoms into interstitial lattice sites on the grain boundary which also contributed to expanding and straining the local lattice.« less

  14. Nano-material and method of fabrication

    DOEpatents

    Menchhofer, Paul A; Seals, Roland D; Howe, Jane Y; Wang, Wei

    2015-02-03

    A fluffy nano-material and method of manufacture are described. At 2000.times. magnification the fluffy nanomaterial has the appearance of raw, uncarded wool, with individual fiber lengths ranging from approximately four microns to twenty microns. Powder-based nanocatalysts are dispersed in the fluffy nanomaterial. The production of fluffy nanomaterial typically involves flowing about 125 cc/min of organic vapor at a pressure of about 400 torr over powder-based nano-catalysts for a period of time that may range from approximately thirty minutes to twenty-four hours.

  15. Uranus moon - Titania

    NASA Technical Reports Server (NTRS)

    1986-01-01

    The terminator region of Titania, one of Uranus' five large moons, was captured in this Voyager 2 image obtained in the early morning hours of Jan. 24, 1986. Voyager was about 500,000 kilometers (300,000 miles) from Titania and inbound toward closest approach. This clear-filter, narrow-angle view is along the terminator -- the line between the sunlit and darkened parts of the moon. The low-angle illumination shows the shape of the surface very clearly. Among the features visible are long linear valleys perhaps 50-100 km (30-60 mi) wide and several hundred km (or mi) long. At least two directions of faulting are visible, as are many circular impact craters attributed to cosmic debris. The resolution of this image is about 9 km (6 mi). The Voyager project is managed for NASA by the Jet Propulsion Laboratory.

  16. Synthesis and polymorphic control for visible light active titania nanoparticles

    NASA Astrophysics Data System (ADS)

    Kaewgun, Sujaree

    Titania (TiO2) is useful for many applications in photocatalysis, antimicrobials, pigment, deodorization, and decomposition of harmful organics and undesirable compounds in the air and waste water under UV irradiation. Among the three phases of TiO2, Rutile, Anatase, and Brookite, studies have been more focused on the anatase and rutile phases. Pure brookite is the most difficult phase to prepare, even under hydrothermal conditions. Predominantly brookite phase TiO2 nanoparticles were prepared by the Water-based Ambient Condition Sol (WACS) process in our laboratory. The objectives of this research were to enhance visible light active (VLA) photocatalytic properties of polymorphic brookite TiO2 by minimizing the lattice defects and narrowing band gap of titania by nitrogen and/or carbon chromophone, and to investigate the deactivation, reusability, and regeneration of the VLA titania in order to design better titania catalysts for organic compound degradation applications. In order to study the influence of hydroxyl content on photocatalytic activities (PCAs) of polymorphic titania nanoparticles, the WACS samples were post-treated by a Solvent-based Ambient Condition Sol (SACS) process in sec-butanol (sec-BuOH). All samples were characterized for phase composition, surface area, hydroxyl contamination, and particle morphology by x-ray diffraction, N2 physisorption, FT-IR, solid state 1H NMR and scanning electron microscopy, and then compared to a commercial titania, Degussa P25. Evaluation of methyl orange (MO) degradation under UV irradiation results showed that the lower lattice hydroxyl content in SACS titania enhanced the PCA. As-prepared titania and SACS samples, which have similar surface areas and crystallinity, were compared in order to prove that the superior PCA came from the reduction in the lattice hydroxyl content. To enhance PCA and VLA properties of WACS, an alternative high boiling point polar solvent, N-methylpyrrolidone (NMP), was utilized in the

  17. Preparation of Cu2ZnSnS4 nano-crystalline powder by mechano-chemical method

    NASA Astrophysics Data System (ADS)

    Alirezazadeh, Farzaneh; Sheibani, Saeed; Rashchi, Fereshteh

    2018-01-01

    Copper zinc tin sulfide (Cu2ZnSnS4, CZTS) is one of the most promising ceramic materials as an absorber layer in solar cells due to its suitable band gap, high absorption coefficient and non-toxic and environmental friendly constituent elements. In this work, nano-crystalline CZTS powder was synthesized by mechanical milling. Elemental powders of Cu, Zn, Sn and were mixed in atomic ratio of 2:1:1:4 according to the stoichiometry of Cu2ZnSnS4 and then milled in a planetary high energy ball mill under argon atmosphere. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and diffusion reflectance spectroscopy (DRS). XRD results confirm the formation of single-phase CZTS with kesterite structure after 20 h of milling. Also, the mean crystallite size was about 35 nm. SEM results show that after 20 h of milling, the product has a relatively uniform particle size distribution. Optical properties of the product indicate that the band gap of prepared CZTS is 1.6 eV which is near to the optimum value for photovoltaic solar cells showing as a light absorber material in solar energy applications.

  18. Synthesis of nano-titanium dioxide by sol-gel route

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kaler, Vandana, E-mail: vandana.kaler@gmail.com; Duchaniya, R. K.; Pandel, U.

    Nanosized titanium dioxide powder was synthesised via sol-gel route by hydrolysis of titanium tetraisopropoxide with ethanol and water mixture in high acidic medium. The synthesized nanopowder was further characterized by X-ray Diffraction, Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, and Ultraviolet Visible Spectroscopy in order to determine size, morphology and crystalline structure of the material. The synthesis of nano-TiO{sub 2} powder in anatase phase was realized by XRD. The optical studies of nano-TiO{sub 2} powder was carried out by UV-Vis spectroscopy and band gap was calculated as 3.5eV, The SEM results with EDAX confirmed that prepared nano-TiO{sub 2} particles weremore » in nanometer range with irregular morphology. The FTIR analysis showed that only desired functional groups were present in sample. These nano-TiO{sub 2} particles have applications in solar cells, chemical sensors and paints, which are thrust areas these days.« less

  19. Synthesis of nano-titanium dioxide by sol-gel route

    NASA Astrophysics Data System (ADS)

    Kaler, Vandana; Duchaniya, R. K.; Pandel, U.

    2016-04-01

    Nanosized titanium dioxide powder was synthesised via sol-gel route by hydrolysis of titanium tetraisopropoxide with ethanol and water mixture in high acidic medium. The synthesized nanopowder was further characterized by X-ray Diffraction, Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, and Ultraviolet Visible Spectroscopy in order to determine size, morphology and crystalline structure of the material. The synthesis of nano-TiO2 powder in anatase phase was realized by XRD. The optical studies of nano-TiO2 powder was carried out by UV-Vis spectroscopy and band gap was calculated as 3.5eV, The SEM results with EDAX confirmed that prepared nano-TiO2 particles were in nanometer range with irregular morphology. The FTIR analysis showed that only desired functional groups were present in sample. These nano-TiO2 particles have applications in solar cells, chemical sensors and paints, which are thrust areas these days.

  20. Perylene and Perylene-Derivative Nano-Cocrystals: Preparation and Physicochemical Property

    NASA Astrophysics Data System (ADS)

    Baba, Koichi; Konta, Sayaka; Oliveira, Daniel; Sugai, Kenji; Onodera, Tsunenobu; Masuhara, Akito; Kasai, Hitoshi; Oikawa, Hidetoshi; Nakanishi, Hachiro

    2012-12-01

    Organic nano-cocrystals of functional dyes of perylene and a perylene derivative were successfully prepared by the reprecipitation method. The particle sizes, optical properties, and powder X-ray diffraction patterns of nano-cocrystals were evaluated. Typically, the size with size distribution of nano-cocrystals was 55±15 nm when the molar ratio of perylene to the perylene derivative was 50:50. The particular intermolecular electronic interaction between perylene and the perylene derivative in the nano-cocrystal state was observed by absorption and fluorescence spectra measurements. The powder X-ray diffraction pattern analysis confirmed that the structure of nano-cocrystals was different from those prepared from perylene and the perylene derivative. The nano-cocrystal having unique physicochemical properties will be potentially classified as a new type of functional nanomaterial.

  1. Biocompatibility assessment of SiO2-TiO2 composite powder on MG63 osteoblast cell lines for orthopaedic applications.

    PubMed

    Chellappa, Maniickam; Thejaswini, Bezawada; Vijayalakshmi, Uthirapathy

    2017-02-01

    The objective of this study is to evaluate the biocompatibility of composite powder consisting of silica and titania (SiO 2 -TiO 2 ) for biomedical applications. The advancement of nanoscience and nanotechnology encourages researchers to actively participate in reinvention of existing materials with improved physical, chemical and biological properties. Hence, a composite/hybrid material has given birth of new materials with intriguing properties. In the present investigation, SiO 2 -TiO 2 composite powder was synthesised by sol-gel method and the prepared nanocomposite was characterised for its phase purity, functional groups, surface topography by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy. Furthermore, to understand the adverse effects of composite, biocompatibility test was analysed by cell culture method using MG63 osteoblast cell lines as a basic screening method. From the results, it was observed that typical Si-O-Ti peaks in FT-IR confirms the formation of composite and the crystallinity of the composite powder was analysed by XRD analysis. Further in vitro biocompatibility and acridine orange results have indicated better biocompatibility at different concentrations on osteoblast cell lines. On the basis of these observations, we envision that the prepared silica-titania nanocomposite is an intriguing biomaterial for better biomedical applications.

  2. Influence of different heat treatment methods of titania film on performance of DSSCs

    NASA Astrophysics Data System (ADS)

    More, Venumadhav; Mokurala, Krishna; Bhargava, Parag

    2018-04-01

    Titania mesoporous film is a key component of dye-sensitized solar cells (DSSCs) as it transfers electrons from dye molecule to external circuit through the transparent conducting oxide (TCO). Interparticle connectivity, porosity and cracks in the titania films play an important role in determining the performance of DSSCs. The heating schedule with respect to the repetitive coating to build up titania film thickness impacts the titania film characteristics. In the present study, experiments were designed to carry out heat treatments with expectation of improving connectivity and healing cracks. Repetitive screen printing was carried out with either heat treatment after each print step (multiple sintering) or the heat treatment was carried out just once after the desired thickness had been attained (single-step sintering). Interconnectivity of the titania particles in the sintered titania film was analyzed by impedance spectroscopy and nanoindentation. Titania films sintered by MS showed better performance in terms of higher efficiency for the corresponding DSSCs than those prepared using titania films sintered by SS.

  3. Preparation and electrocatalytic activity of tungsten carbide and titania nanocomposite

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hu, Sujuan; Shi, Binbin; Yao, Guoxing

    2011-10-15

    Graphical abstract: The electrocatalytic activity of tungsten carbide and titania nanocomposite is related to the structure, crystal phase and chemical components of the nanocomposite, and is also affected by the property of electrolyte. A synergistic effect exists between tungsten carbide and titania of the composite. Highlights: {yields} Electrocatalytic activity of tungsten carbide and titania nanocomposite with core-shell structure. {yields} Activity is related to the structure, crystal phase and chemical component of the nanocomposite. {yields} The property of electrolyte affects the electrocatalytic activity. {yields} A synergistic effect exists between tungsten carbide and titania of the composite. -- Abstract: Tungsten carbide andmore » titania nanocomposite was prepared by combining a reduced-carbonized approach with a mechanochemical approach. The samples were characterized by X-ray diffraction, transmission electron microscope under scanning mode and X-ray energy dispersion spectrum. The results show that the crystal phases of the samples are composed of anatase, rutile, nonstoichiometry titanium oxide, monotungsten carbide, bitungsten carbide and nonstoichiometry tungsten carbide, and they can be controlled by adjusting the parameters of the reduced-carbonized approach; tungsten carbide particles decorate on the surface of titania support, the diameter of tungsten carbide particle is smaller than 20 nm and that of titania is around 100 nm; the chemical components of the samples are Ti, O, W and C. The electrocatalytic activity of the samples was measured by a cyclic voltammetry with three electrodes. The results indicate that the electrocatalytic activities of the samples are related to their crystal phases and the property of electrolyte in aqueous solution. A synergistic effect between titania and tungsten carbide is reported for the first time.« less

  4. Fabrication of Titania Nanotubes for Gas Sensing Applications

    NASA Astrophysics Data System (ADS)

    Dzilal, A. A.; Muti, M. N.; John, O. D.

    2010-03-01

    Detection of hydrogen is needed for industrial process control and medical applications where presence of hydrogen indicates different type of health problems. Titanium dioxide nanotube structure is chosen as an active component in the gas sensor because of its highly sensitive electrical resistance to hydrogen over a wide range of concentrations. The objective of the work is to fabricate good quality titania nanotubes suitable for hydrogen sensing applications. The fabrication method used is anodizing method. The anodizing parameters namely the voltage, time duration, concentration of hydrofluoric acid in water, separation between the electrodes and the ambient temperature are varied accordingly to find the optimum anodizing conditions for production of good quality titania nanotubes. The highly ordered porous titania nanotubes produced by this method are in tabular shape and have good uniformity and alignment over large areas. From the investigation done, certain set of anodizing parameters have been found to produce good quality titania nanotubes with diameter ranges from 47 nm to 94 nm.

  5. Suspension Plasma Spray Fabrication of Nanocrystalline Titania Hollow Microspheres for Photocatalytic Applications

    NASA Astrophysics Data System (ADS)

    Ren, Kun; Liu, Yi; He, Xiaoyan; Li, Hua

    2015-10-01

    Hollow inorganic microspheres with controlled internal pores in close-cell configuration are usually constructed by submicron-sized particles. Fast and efficient large-scale production of the microspheres with tunable sizes yet remains challenging. Here, we report a suspension plasma spray route for making hollow microspheres from nano titania particles. The processing permits most nano particles to retain their physiochemical properties in the as-sprayed microspheres. The microspheres have controllable interior cavities and mesoporous shell of 1-3 μm in thickness. Spray parameters and organic content in the starting suspension play the key role in regulating the efficiency of accomplishing the hollow sphere structure. For the ease of collecting the spheres for recycling use, ferriferous oxide particles were used as additives to make Fe3O4-TiO2 hollow magnetic microspheres. The spheres can be easily recycled through external magnetic field collection after each time use. Photocatalytic anti-bacterial activities of the hollow spheres were assessed by examining their capability of degrading methylene blue and sterilizing Escherichia coli bacteria. Excellent photocatalytic performances were revealed for the hollow spheres, giving insight into their potential versatile applications.

  6. Molecular and physiological responses to titanium dioxide ...

    EPA Pesticide Factsheets

    - Changes in tissue transcriptomes and productivity of Arabidopsis thaliana were investigated during exposure of plants to two widely-used engineered metal oxide nanoparticles, titanium dioxide (nano-titanium) and cerium dioxide (nano-cerium). Microarray analyses confirmed that exposure to either nanoparticle altered the transcriptomes of rosette leaves and roots, with comparatively larger numbers of differentially expressed genes (DEGs) found under nano-titania exposure. Nano-titania induced more DEGs in rosette leaves, whereas roots had more DEGs under nano-ceria exposure. MapMan analyses indicated that while nano-titania up-regulated overall and secondary metabolism in both tissues, metabolic processes under nano-ceria remained mostly unchanged. Gene enrichment analysis indicated that both nanoparticles mainly enriched ontology groups such as responses to stress (abiotic and biotic), and defense responses (pathogens), and responses to endogenous stimuli (hormones). Nano-titania specifically induced genes associated with photosynthesis, whereas nano-ceria induced expression of genes related to activating transcription factors, most notably those belonging to the ethylene responsive element binding protein family. Interestingly, there were also increased numbers of rosette leaves and plant biomass under nano-ceria exposure, but not under nano-titania. Other transcriptomic responses did not clearly relate to responses observed at the organism level. This may b

  7. Improvement of mechanical and thermal properties of high energy electron beam irradiated HDPE/hydroxyapatite nano-composite

    NASA Astrophysics Data System (ADS)

    Mohammadi, M.; Ziaie, F.; Majdabadi, A.; Akhavan, A.; Shafaei, M.

    2017-01-01

    In this research work, the nano-composites of high density polyethylene/hydroxyapatite samples were manufactured via two methods: In the first method, the granules of high density polyethylene and nano-structure hydroxyapatite were processed in an internal mixer to prepare the nano-composite samples with a different weight percentage of the reinforcement phase. As for the second one, high density polyethylene was prepared in nano-powder form in boiling xylene. During this procedure, the hydroxyapatite nano-powder was added with different weight percentages to the solvent to obtain the nano-composite. In both of the procedures, the used hydroxyapatite nano-powder was synthesized via hydrolysis methods. The samples were irradiated under 10 MeV electron beam in 70-200 kGy of doses. Mechanical, thermal and morphological properties of the samples were investigated and compared. The results demonstrate that the nano-composites which we have prepared using nano-polyethylene, show better mechanical and thermal properties than the composites prepared from normal polyethylene granules, due to the better dispersion of nano-particles in the polymer matrix.

  8. Nano-liposomal dry powder inhaler of tacrolimus: preparation, characterization, and pulmonary pharmacokinetics.

    PubMed

    Chougule, Mahavir; Padhi, Bijay; Misra, Ambikanandan

    2007-01-01

    The studies were undertaken to evaluate feasibility of pulmonary delivery of liposomaly encapsulated tacrolimus dry powder inhaler for prolonged drug retention in lungs as rescue therapy to prevent refractory rejection of lungs after transplantation. Tacrolimus encapsulated liposomes were prepared by thin film evaporation technique and liposomal dispersion was passed through high pressure homogenizer. Tacrolimus nano-liposomes (NLs) were separated by centrifugation and characterized. NLs were dispersed in phosphate buffer saline (PBS) pH 7.4 containing different additives like lactose, sucrose, and trehalose, and L-leucine as antiadherent. The dispersion was spray dried and spray dried powders were characterized. In vitro and in vivo pulmonary deposition was performed using Andersen Cascade Impactor and intratracheal instillation in rats respectively. NLs were found to have average size of 140 nm, 96% +/- 1.5% drug entrapment, and zeta potential of 1.107 mV. Trehalose based formulation was found to have low density, good flowability, particle size of 9.46 +/- 0.8 microm, maximum fine particle fraction (FPF) of 71.1 +/- 2.5%, mean mass aerodynamic diameter (MMAD) 2.2 +/- 0.1 microm, and geometric standard deviation (GSD) 1.7 +/- 0.2. Developed formulations were found to have in vitro prolonged drug release up to 18 hours, following Higuchi's Controlled Release model. In vivo studies revealed maximal residence of tacrolimus within lungs of 24 hours, suggesting slow clearance from the lungs. The investigation provides a practical approach for direct delivery of tacrolimus encapsulated in NLs for controlled and prolonged retention at the site of action. It may play a promising role as rescue therapy in reducing the risk of acute rejection and chronic rejection.

  9. [Raman spectrum of nano-graphite synthesized by explosive detonation].

    PubMed

    Wen, Chao; Li, Xun; Sun, De-Yu; Guan, Jin-Qing; Liu, Xiao-Xin; Lin, Ying-Rui; Tang, Shi-Ying; Zhou, Gang; Lin, Jun-De; Jin, Zhi-Hao

    2005-01-01

    The nano-graphite powder synthesized by the detonation of explosives with negative oxygen balance is a new powder material with potential applications. In this work, the preparation of nano-graphite powder in steel chamber by pure TNT (trinitrotoluene) explosives has been introduced. In the synthesis process, the protective gases in the steel chamber are N2, CO2 and Ar, and the pressure is 0.25-2 atm. Raman spectrum of the nano-graphite was measured. The characteristic Raman band assigned to sp2 of graphite has been observed at about 1 585 cm(-1) with half-peak width of 22 cm(-1). The peak shifted to a higher frequency by 5 cm(-1) compared with that of bulk graphite. The authors explain this blue shift phenomenon by size effect. The average size of nanographite from Raman measurement is 2.97-3.97 nm. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to measure the structure and particle size of the nano-graphite. The crystallite size of nano-graphite estimated from XRD andTEM are 2.58 nm (acid untreated) and 1.86 nm (acid treated) respectively, which is in accord with the results of the measurement approximately.

  10. Enhanced stability of catalase covalently immobilized on functionalized titania submicrospheres.

    PubMed

    Wu, Hong; Liang, Yanpeng; Shi, Jiafu; Wang, Xiaoli; Yang, Dong; Jiang, Zhongyi

    2013-04-01

    In this study, a novel approach combing the chelation and covalent binding was explored for facile and efficient enzyme immobilization. The unique capability of titania to chelate with catecholic derivatives at ambient conditions was utilized for titania surface functionalization. The functionalized titania was then used for enzyme immobilization. Titania submicrospheres (500-600 nm) were synthesized by a modified sol-gel method and functionalized with carboxylic acid groups through a facile chelation method by using 3-(3,4-dihydroxyphenyl) propionic acid as the chelating agent. Then, catalase (CAT) was covalently immobilized on these functionalized titania submicrospheres through 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride/N-hydroxysuccinimide (EDC/NHS) coupling reaction. The immobilized CAT retained 65% of its free form activity with a loading capacity of 100-150 mg/g titania. The pH stability, thermostability, recycling stability and storage stability of the immobilized CAT were evaluated. A remarkable enhancement in enzyme stability was achieved. The immobilized CAT retained 90% and 76% of its initial activity after 10 and 16 successive cycles of decomposition of hydrogen peroxide, respectively. Both the Km and the Vmax values of the immobilized CAT (27.4 mM, 13.36 mM/min) were close to those of the free CAT (25.7 mM, 13.46 mM/min). Copyright © 2012 Elsevier B.V. All rights reserved.

  11. Reactive magnetron sputtering deposition of bismuth tungstate onto titania nanoparticles for enhancing visible light photocatalytic activity

    NASA Astrophysics Data System (ADS)

    Ratova, Marina; Kelly, Peter J.; West, Glen T.; Tosheva, Lubomira; Edge, Michele

    2017-01-01

    Titanium dioxide - bismuth tungstate composite materials were prepared by pulsed DC reactive magnetron sputtering of bismuth and tungsten metallic targets in argon/oxygen atmosphere onto anatase and rutile titania nanoparticles. The use of an oscillating bowl placed beneath the two magnetrons arranged in a co-planar closed field configuration enabled the deposition of bismuth tungstate onto loose powders, rather than a solid substrate. The atomic ratio of the bismuth/tungsten coatings was controlled by varying the power applied to each target. The effect of the bismuth tungstate coatings on the phase, optical and photocatalytic properties of titania was investigated by X-ray diffraction, energy-dispersive X-ray spectroscopy (EDX), Brunauer-Emmett-Teller (BET) surface area measurements, transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy and an acetone degradation test. The latter involved measurements of the rate of CO2 evolution under visible light irradiation of the photocatalysts, which indicated that the deposition of bismuth tungstate resulted in a significant enhancement of visible light activity, for both anatase and rutile titania particles. The best results were achieved for coatings with a bismuth to tungsten atomic ratio of 2:1. In addition, the mechanism by which the photocatalytic activity of the TiO2 nanoparticles was enhanced by compounding it with bismuth tungstate was studied by microwave cavity perturbation. The results of these tests confirmed that such enhancement of the photocatalytic properties is due to more efficient photogenerated charge carrier separation, as well as to the contribution of the intrinsic photocatalytic properties of Bi2WO6.

  12. Titania nanotubes prepared by rapid breakdown anodization for photocatalytic decolorization of organic dyes under UV and natural solar light.

    PubMed

    Ali, Saima; Granbohm, Henrika; Lahtinen, Jouko; Hannula, Simo-Pekka

    2018-06-14

    Titania nanotube (TNT) powder was prepared by rapid breakdown anodization (RBA) in a perchloric acid electrolyte. The photocatalytic efficiency of the as-prepared and powders annealed at temperatures between 250 and 550 °C was tested under UV and natural sunlight irradiation by decolorization of both anionic and cationic organic dyes, i.e., methyl orange (MO) and rhodamine B (RhB), as model pollutants. The tubular structure of the nanotubes was retained up to 250 °C, while at 350 °C and above, the nanotubes transformed into nanorods and nanoparticles. Depending on the annealing temperature, the TNTs consist of anatase, mixed anatase/brookite, or anatase/rutile phases. The bandgap of the as-prepared nanotubes is 3.04 eV, and it shifts towards the visible light region upon annealing. The X-ray photoelectron spectroscopy (XPS) results show the presence of titania and impurities including chlorine on the surface of the TNTs. The atomic ratio of Ti/O remains unchanged for the annealed TNTs, but the concentration of chlorine decreases with temperature. The photoluminescence (PL) indicate high electron-hole recombination for the as-prepared TNTs, probably due to the residual impurities, low crystallinity, and vacancies in the structure, while the highest photocurrent was observed for the TNT sample annealed at 450 °C. The TNTs induce a small degradation of the dyes under UV light; however, contrary to previous reports, complete decolorization of dyes is observed under sunlight. All TNT samples showed higher decolorization rates under sunlight irradiation than under UV light. The highest reaction rate for the TNT samples was obtained for the as-prepared TNT powder sample under sunlight using RhB (κ 1  = 1.29 h -1 ). This is attributed to the bandgap, specific surface area and the crystal structure of the nanotubes. The as-prepared TNTs performed most efficiently for decolorization of RhB and outperformed the reference anatase powder under sunlight irradiation

  13. Controlled growth of silica-titania hybrid functional nanoparticles through a multistep microfluidic approach.

    PubMed

    Shiba, K; Sugiyama, T; Takei, T; Yoshikawa, G

    2015-11-11

    Silica/titania-based functional nanoparticles were prepared through controlled nucleation of titania and subsequent encapsulation by silica through a multistep microfluidic approach, which was successfully applied to obtaining aminopropyl-functionalized silica/titania nanoparticles for a highly sensitive humidity sensor.

  14. A review on the application of inorganic nano-structured materials in the modification of textiles: focus on anti-microbial properties.

    PubMed

    Dastjerdi, Roya; Montazer, Majid

    2010-08-01

    Textiles can provide a suitable substrate to grow micro-organisms especially at appropriate humidity and temperature in contact to human body. Recently, increasing public concern about hygiene has been driving many investigations for anti-microbial modification of textiles. However, using many anti-microbial agents has been avoided because of their possible harmful or toxic effects. Application of inorganic nano-particles and their nano-composites would be a good alternative. This review paper has focused on the properties and applications of inorganic nano-structured materials with good anti-microbial activity potential for textile modification. The discussed nano-structured anti-microbial agents include TiO(2) nano-particles, metallic and non-metallic TiO(2) nano-composites, titania nanotubes (TNTs), silver nano-particles, silver-based nano-structured materials, gold nano-particles, zinc oxide nano-particles and nano-rods, copper nano-particles, carbon nanotubes (CNTs), nano-clay and its modified forms, gallium, liposomes loaded nano-particles, metallic and inorganic dendrimers nano-composite, nano-capsules and cyclodextrins containing nano-particles. This review is also concerned with the application methods for the modification of textiles using nano-structured materials. Copyright 2010 Elsevier B.V. All rights reserved.

  15. Ultra-high aspect ratio titania nanoflakes for dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Lee, Yang-Yao; El-Shall, Hassan

    2017-12-01

    Micron sized titania flakes with thickness about 40 nm were used in the titania pastes to assemble dye-sensitized solar cells (DSSCs). Using the same deposition method, better particle dispersion of titania flakes resulted in well bonded and integral films comparing to cracking of Degussa P25 nanoparticle films during the evaporation and sintering processes. There are two features of titania flakes which leads to improved conversion efficiency of DSSC: (1) Higher and stronger adsorption of N-719 dyes due to high specific surface area (2) Stronger light scattering of visible light spectrum because of micron scale wide in two dimensions of the flakes. The thickness of the conducting TiO2 was critical to the IV characteristics of DSSC such as the short-circuit current density (Isc) and open-circuit voltage (Voc). Under the same thickness basis, calcined titania flakes provided 5 times higher efficiency than the photoelectrodes consisted of Degussa P25 nanoparticles (7.4% vs. 1.2%).

  16. Molecularly imprinted titania nanoparticles for selective recognition and assay of uric acid

    NASA Astrophysics Data System (ADS)

    Mujahid, Adnan; Khan, Aimen Idrees; Afzal, Adeel; Hussain, Tajamal; Raza, Muhammad Hamid; Shah, Asma Tufail; uz Zaman, Waheed

    2015-06-01

    Molecularly imprinted titania nanoparticles are su ccessfully synthesized by sol-gel method for the selective recognition of uric acid. Atomic force microscopy is used to study the morphology of uric acid imprinted titania nanoparticles with diameter in the range of 100-150 nm. Scanning electron microscopy images of thick titania layer indicate the formation of fine network of titania nanoparticles with uniform distribution. Molecular imprinting of uric acid as well as its subsequent washing is confirmed by Fourier transformation infrared spectroscopy measurements. Uric acid rebinding studies reveal the recognition capability of imprinted particles in the range of 0.01-0.095 mmol, which is applicable in monitoring normal to elevated levels of uric acid in human blood. The optical shift (signal) of imprinted particles is six times higher in comparison with non-imprinted particles for the same concentration of uric acid. Imprinted titania particles have shown substantially reduced binding affinity toward interfering and structurally related substances, e.g. ascorbic acid and guanine. These results suggest the possible application of titania nanoparticles in uric acid recognition and quantification in blood serum.

  17. Magnetically responsive enzyme powders

    NASA Astrophysics Data System (ADS)

    Pospiskova, Kristyna; Safarik, Ivo

    2015-04-01

    Powdered enzymes were transformed into their insoluble magnetic derivatives retaining their catalytic activity. Enzyme powders (e.g., trypsin and lipase) were suspended in various liquid media not allowing their solubilization (e.g., saturated ammonium sulfate and highly concentrated polyethylene glycol solutions, ethanol, methanol, 2-propanol) and subsequently cross-linked with glutaraldehyde. Magnetic modification was successfully performed at low temperature in a freezer (-20 °C) using magnetic iron oxides nano- and microparticles prepared by microwave-assisted synthesis from ferrous sulfate. Magnetized cross-linked enzyme powders were stable at least for two months in water suspension without leakage of fixed magnetic particles. Operational stability of magnetically responsive enzymes during eight repeated reaction cycles was generally without loss of enzyme activity. Separation of magnetically modified cross-linked powdered enzymes from reaction mixtures was significantly simplified due to their magnetic properties.

  18. Methods of making non-covalently bonded carbon-titania nanocomposite thin films and applications of the same

    DOEpatents

    Liang, Yu Teng; Vijayan, Baiju K.; Gray, Kimberly A.; Hersam, Mark C.

    2016-07-19

    In one aspect, a method of making non-covalently bonded carbon-titania nanocomposite thin films includes: forming a carbon-based ink; forming a titania (TiO.sub.2) solution; blade-coating a mechanical mixture of the carbon-based ink and the titania solution onto a substrate; and annealing the blade-coated substrate at a first temperature for a first period of time to obtain the carbon-based titania nanocomposite thin films. In certain embodiments, the carbon-based titania nanocomposite thin films may include solvent-exfoliated graphene titania (SEG-TiO.sub.2) nanocomposite thin films, or single walled carbon nanotube titania (SWCNT-TiO.sub.2) nanocomposite thin films.

  19. Nano-liposomal dry powder inhaler of tacrolimus: Preparation, characterization, and pulmonary pharmacokinetics

    PubMed Central

    Chougule, Mahavir; Padhi, Bijay; Misra, Ambikanandan

    2007-01-01

    The studies were undertaken to evaluate feasibility of pulmonary delivery of liposomaly encapsulated tacrolimus dry powder inhaler for prolonged drug retention in lungs as rescue therapy to prevent refractory rejection of lungs after transplantation. Tacrolimus encapsulated liposomes were prepared by thin film evaporation technique and liposomal dispersion was passed through high pressure homogenizer. Tacrolimus nano-liposomes (NLs) were separated by centrifugation and characterized. NLs were dispersed in phosphate buffer saline (PBS) pH 7.4 containing different additives like lactose, sucrose, and trehalose, and L-leucine as antiadherent. The dispersion was spray dried and spray dried powders were characterized. In vitro and in vivo pulmonary deposition was performed using Andersen Cascade Impactor and intratracheal instillation in rats respectively. NLs were found to have average size of 140 nm, 96% ± 1.5% drug entrapment, and zeta potential of 1.107 mV. Trehalose based formulation was found to have low density, good flowability, particle size of 9.46 ± 0.8 μm, maximum fine particle fraction (FPF) of 71.1 ± 2.5%, mean mass aerodynamic diameter (MMAD) 2.2 ± 0.1 μm, and geometric standard deviation (GSD) 1.7 ± 0.2. Developed formulations were found to have in vitro prolonged drug release up to 18 hours, following Higuchi’s Controlled Release model. In vivo studies revealed maximal residence of tacrolimus within lungs of 24 hours, suggesting slow clearance from the lungs. The investigation provides a practical approach for direct delivery of tacrolimus encapsulated in NLs for controlled and prolonged retention at the site of action. It may play a promising role as rescue therapy in reducing the risk of acute rejection and chronic rejection. PMID:18203434

  20. Characterization of microwave assisted sintered graphene toughened alumina (GTA) nano composites

    NASA Astrophysics Data System (ADS)

    Vandana, K. I. Vishnu; Suman, K. N. S.; Viswabaskaran, V.

    2017-07-01

    The objective of the present work is to characterize different mechanical properties of a nano composite made out of a combination of nano alumina and nano graphene. The nano powders of alumina and Graphene were mixed using High Energy Ball Mill and weight ratio of Al:G-C was maintained in the range of 0 to 2wt%. The prepared alumoorganic nano Composite Powders were compacted by Uniaxial Pellet Press and Graphene Toughened alumina (GTA) based composites were sintered in inert atmosphere at 1600°C using Hybrid Microwave Furnace. XRD and SEM studies are conducted on these specimens. Density and hardness tests are also performed on these specimens. In addition, wear and fracture toughness tests will also be carried out. In order to strengthen the experimental observations obtained, theoretical interpretation will be given to enhance the present work.

  1. Synthesis and characterization of fluorapatite-titania (FAp-TiO 2) nanocomposite via mechanochemical process

    NASA Astrophysics Data System (ADS)

    Ebrahimi-Kahrizsangi, Reza; Nasiri-Tabrizi, Bahman; Chami, Akbar

    2010-09-01

    In this paper, synthesis of bionanocomposite of fluorapatite-titania (FAp-TiO 2) was studied by using one step mechanochemical process. Characterization of the products was accomplished by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques. Based on XRD patterns and FT-IR spectroscopy, correlation between the structural features of the nanostructured FAp-TiO 2 and the process conditions was discussed. Variations in crystallite size, lattice strain, and volume fraction of grain boundary were investigated during milling and the following heat treatment. Crystallization of the nanocomposite occurred after thermal treatment at 650 °C. Morphological features of powders were influenced by the milling time. The resulting FAp-20 wt.%TiO 2 nanocomposite powder exhibited an average particle size of 15 nm after 20 h of milling. The results show that the one step mechanosynthesis technique is an effective route to prepare FAp-based nanocomposites with excellent morphological and structural features.

  2. New method to synthesize mesoporous titania by photodegradation of surfactant template

    NASA Astrophysics Data System (ADS)

    Zi, Shamsuddin Chik; Chandren, Sheela; Yuan, Lai Sin; Razali, Rasidah; Ho, Chin Siong; Hartanto, Djoko; Indra Mahlia, Teuku Meurah; Nur, Hadi

    2016-02-01

    Mesoporous titania has been successfully synthesized by photodegradation removal of cetyltrimethylammonium bromide as the surfactant, after slow hydrolyzation of titanium(IV) isopropoxide. Fourier transform infrared spectra proved that photodegradation has successfully decreased the peak areas of the alkyl groups from the template. The nitrogen adsorption analysis showed that the pore size and the specific surface area of the mesoporous titania were 3.7 nm and 203 m2 g-1, respectively, proving the mesoporosity of the titania obtained with the existence of the interparticle mesoporosity which was confirmed by transmission electron microscopy. Based on X-ray diffraction results, the mesoporous titania obtained was in the form of crystalline anatase phase. Furthermore, results from the diffuse reflectance ultra violet-visible spectra showed that the composition of tetrahedral titanium(IV) was more than the octahedral titanium(IV). When the mesoporous titania obtained was used as a catalyst in the oxidation of styrene, an improvement in the conversion of styrene (38%) was observed when compared to those obtained using Degussa P25 TiO2 (14%) as the catalyst.

  3. Titania nanospheres from supercritical fluids.

    PubMed

    Darr, J A; Kellici, S; Rehman, I U

    2005-06-01

    Surfactant-coated amorphous titania nanospheres have been synthesised using templating 'water-in-supercritical carbon dioxide' emulsion droplets; the process represents a clean and controlled method for the manufacture of high-purity nanoparticles.

  4. Synthesis and Characterization of BaFe12O19 Thin Films Using Suspension of Nano Powders

    NASA Astrophysics Data System (ADS)

    Salemizadeh, Saman; Seyyed Ebrahimi, S. A.

    BaM thin films have been synthesized by dispersing the dried gel nano powders prepared by Sol-Gel method. The solution was made by dissolving iron nitrate Fe(NO3).9H2O, barium nitrate Ba(NO3)2 and citric acid in deyonized water and methanol. This sol was slowly evaporated until a dried gel was formed. This dried gel was then added to ethylene glycol. The final solution was vigorously shaken and mixed in ultrasonic cleaner for 30 min to disperse particles sufficiently. Then the prepared solution spin coated on Si(110) substrate. The obtained thin films were dried at 120 °C and then calcined at 900 °C for 1 h. The films were characterized using X-ray diffraction (XRD) and vibrating sample magnetometer (VSM).

  5. Surface science studies on titania for solar fuel applications

    NASA Astrophysics Data System (ADS)

    Hadsell, Courtney Sara Mathews

    Titanium dioxide (titania) is a well-studied material for various applications including but not limited to, paint, sunscreen, pharmaceuticals and solar cell applications (photocatalysis.) It can be found in three main crystal forms; rutile, anatase, and brookite and this work will focus on the anatase form which has been heavily studied for its potential in dye sensitized solar cells (DSSCs.) I propose that aqueous and photo dye stability can be improved by taking special care to the exposed surface of anatase. Additionally, the theoretical maximum open circuit voltage of a DSSC is dependent upon which surface is exposed to the electrolyte. Previous works in this area have not been rigorous with respect to the surface and morphology of titania being used. Standard synthesis techniques of anatase lead to a crystal that generally has 94% of the titania (101) surface exposed, and the other 6% is the higher energy (001) surface. The (101) surface has 5 & 6-fold coordinated titania whereas the (001) surface only has 5-fold (under) coordinated titania. This under-coordination leads to enhanced reactivity of the (001) surface which has been demonstrated by dissassociative adsorption of water, and catalysis applications. Much theoretical work has focused on the minority (001) surface because up until recently synthesizing anatase with enhanced exposure of the (001) surface has been difficult. The initial materials for this study will be multilayer titania nanotubes (TiNTs) and nanosheets (TiNS) which have been previously characterized by my predecessor. The TiNTs and TiNS have 100% exposed (001)-like surface. Both of these materials show enhanced stability of phosphonated dye binding as compared to the current standard of anatase nanoparticles (NPs) however, due to their limited thermal stability the potential of incorporating the TiNTs and TiNSs into devices has been eliminated in this study. To overcome the device limitations I will synthesis a novel titania nanotile

  6. Giant dielectric constant in titania nanoparticles embedded in conducting polymer matrix.

    PubMed

    Dey, Ashis; De, Sukanta; De, Amitabha; De, S K

    2006-05-01

    Complex impedance and dielectric permittivity of titania-polypyrrole nanocomposites have been investigated as a function of frequency and temperature at different compositions. A very large dielectric constant of about 13,000 at room temperature has been observed. The colossal dielectric constant is mainly dominated by interfacial polarization due to Maxwell-Wagner relaxation effect. Two completely separate groups of dielectric relaxation have been observed. The low frequency dielectric relaxation arises from surface defect states of titania nanoparticles. The broad peak at high frequency region is attributed to Maxwell-Wagner type polarization originating from the inhomogeneous property of nanocomposite. An abrupt change in grain boundary conductivity and dielectric relaxation associated with titania was observed at around 150 K. Anomalous behavior in conductivity and dielectric relaxation is qualitatively explained by band tail structure of titania nanoparticle.

  7. The Effect of Multi-pass Equal-Channel Angular Pressing (ECAP) for Consolidation of Aluminum-Nano Alumina Composite Powder on Wear Resistance

    NASA Astrophysics Data System (ADS)

    Derakhshandeh-Haghighi, Reza; Jenabali Jahromi, Seyed Ahmad

    2016-02-01

    The wear behavior of aluminum matrix composite powder with varying concentration of nano alumina particles, which was consolidated by equal-channel angular pressing (ECAP) at different passes, was determined by applying, 10 and 46 N loads, using a pin-on-disk machine. Optical and electronic microscopy, EDX analysis, and hardness measurement were performed in order to characterize the worn samples. The relative density of the samples after each pass of ECAP was determined using Archimedes principle. Within the studied range of loads, the wear loss decreased by increasing the number of ECAP passes.

  8. A convenient sol-gel route for the synthesis of salicylate-titania nanocomposites having visible absorption and blue luminescence

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Mitra, Atanu; Bhaumik, Asim, E-mail: msab@iacs.res.i; Nandi, Mahasweta

    2009-05-15

    Syntheses of titania-based nanomaterials by simple sol-gel route using a mixture of CTAB and salicylate as well as salicylate ions as templates have been reported. The materials are characterized by the powder X-ray diffraction (XRD), thermal analysis, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and spectroscopic (FT IR, UV-VIS) analyses. A disordered mesoscale orientation of nanoparticles (ca. 2-4 nm) composed of TiO{sub 2}-salicylate surface complex has been obtained when 1:1 mixing ratio of CTAB and salicylate at the CTAB concentration of 0.001 M was employed as a template. All these nanocomposites exhibit a considerable red shift at the onsetsmore » of their absorption band compared to pure (organic-free) nanocrystalline TiO{sub 2} and show blue luminescence at room temperature. This assembly of nanoparticles is highly interesting in the context of visible light sensitization and nanodevice fabrication. - Graphical abstract: A new titania-salicylate nanostructure material has been synthesized, which exhibit a considerable red shift towards the visible region vis-a-vis nanocrystalline (organic-free) TiO{sub 2} and blue luminescence at room temperature.« less

  9. Improved compaction of ZnO nano-powder triggered by the presence of acetate and its effect on sintering.

    PubMed

    Dargatz, Benjamin; Gonzalez-Julian, Jesus; Guillon, Olivier

    2015-04-01

    The retention of nanocrystallinity in dense ceramic materials is still a challenge, even with the application of external pressure during sintering. The compaction behavior of high purity and acetate enriched zinc oxide (ZnO) nano-powders was investigated. It was found that acetate in combination with water plays a key role during the compaction into green bodies at moderate temperatures. Application of constant pressure resulted in a homogeneous green body with superior packing density (86% of theoretical value) at moderate temperature (85 °C) in the presence of water. In contrast, no improvement in density could be achieved if pure ZnO powder was used. This compaction behavior offers superior packing of the particles, resulting in a high relative density of the consolidated compact with negligible coarsening. Dissolution accompanying creep diffusion based matter transport is suggested to strongly support reorientation of ZnO particles towards densities beyond the theoretical limit for packing of ideal monosized spheres. Finally, the sintering trajectory reveals that grain growth is retarded compared to conventional processing up to 90% of theoretical density. Moreover, nearly no radial shrinkage was observed after sinter-forging for bodies performed with this advanced processing method.

  10. Improved compaction of ZnO nano-powder triggered by the presence of acetate and its effect on sintering

    PubMed Central

    Gonzalez-Julian, Jesus; Guillon, Olivier

    2015-01-01

    The retention of nanocrystallinity in dense ceramic materials is still a challenge, even with the application of external pressure during sintering. The compaction behavior of high purity and acetate enriched zinc oxide (ZnO) nano-powders was investigated. It was found that acetate in combination with water plays a key role during the compaction into green bodies at moderate temperatures. Application of constant pressure resulted in a homogeneous green body with superior packing density (86% of theoretical value) at moderate temperature (85 °C) in the presence of water. In contrast, no improvement in density could be achieved if pure ZnO powder was used. This compaction behavior offers superior packing of the particles, resulting in a high relative density of the consolidated compact with negligible coarsening. Dissolution accompanying creep diffusion based matter transport is suggested to strongly support reorientation of ZnO particles towards densities beyond the theoretical limit for packing of ideal monosized spheres. Finally, the sintering trajectory reveals that grain growth is retarded compared to conventional processing up to 90% of theoretical density. Moreover, nearly no radial shrinkage was observed after sinter-forging for bodies performed with this advanced processing method. PMID:27877777

  11. Preparation and characterization of titania-deposited silica composite hollow fiber membranes with high hydrothermal stability.

    PubMed

    Kwon, Young-Nam; Kim, In-Chul

    2013-11-01

    Hydrothermal stability of a porous nickel-supported silica membrane was successfully improved by deposition of titania multilayers on colloidal silica particles embedded in the porous nickel fiber support. Porous nickel-supported silica membranes were prepared by means of a dipping-freezing-fast drying (DFF) method. The titania layers were deposited on colloidal silica particles by repeating hydrolysis and condensation reactions of titanium isopropoxide on the silica particle surfaces. The deposition of thin titania layers on the nickel-supported silica membrane was verified by various analytical tools. The water flux and the solute rejection of the porous Ni fiber-supported silica membranes did not change after titania layer deposition, indicating that thickness of titania layers deposited on silica surface is enough thin not to affect the membrane performance. Moreover, improvement of the hydrothermal stability in the titania-deposited silica membranes was confirmed by stability tests, indicating that thin titania layers deposited on silica surface played an important role as a diffusion barrier against 90 degrees C water into silica particles.

  12. Macrostructure-dependent photocatalytic property of high-surface-area porous titania films

    NASA Astrophysics Data System (ADS)

    Kimura, T.

    2014-11-01

    Porous titania films with different macrostructures were prepared with precise control of condensation degree and density of the oxide frameworks in the presence of spherical aggregates of polystyrene-block-poly(oxyethylene) (PS-b-PEO) diblock copolymer. Following detailed explanation of the formation mechanisms of three (reticular, spherical, and large spherical) macrostructures by the colloidal PS-b-PEO templating, structural variation of the titania frameworks during calcination were investigated by X-ray diffraction and X-ray photoelectron spectroscopy. Then, photocatalytic performance of the macroporous titania films was evaluated through simple degradation experiments of methylene blue under an UV irradiation. Consequently, absolute surface area of the film and crystallinity of the titania frameworks were important for understanding the photocatalytic performance, but the catalytic performance can be improved further by the macrostructural design that controls diffusivity of the targeted molecules inside the film and their accessibility to active sites.

  13. A facile sol-gel synthesis of impurity-free nanocrystalline titania.

    PubMed

    Vinogradov, Alexandr V; Ermakova, Al'ena V; Butman, Mikhail F; Hey-Hawkins, Evamarie; Vinogradov, Vladimir V

    2014-06-14

    This paper reports an original technique that provides a highly pure crystalline sol of titania with controllable particle size by ultrasonic activation of the hydrolysis products of titanium isopropoxide in an aqueous medium at a near-neutral pH, which is potentially promising in impurity-sensitive electronics and biochemical engineering. Optimal conditions (H2O/TIP ratio, sonication time, etc.) for preparation of stable nanocrystalline titania sol were adopted. A new mechanism of regulation of aggregation and polycondensation under ultrasonic irradiation is proposed. Entrapment of human serum albumin (HSA) in the formed porous titania matrix results in high thermal stability of the protein dopants: the denaturation temperature of HSA is shifted by 31 °C.

  14. Synthesis and characterization of binary titania-silica mixed oxides

    NASA Astrophysics Data System (ADS)

    Budhi, Sridhar

    A series of binary titania-silica mixed oxides were synthesized by the sol-gel method at room temperature. The mixed oxides were prepared that involved the hydrolysis of titanium isopropoxide and tetraethylorthosilicate (TEOS) by co-solvent induced gelation usually in acidic media. The resulting gels were dried, calcined and then characterized by powder X-ray diffractometric studies, nitrogen sorption studies (at 77K), diffuse reflectance spectroscopy, Raman microscopy and transmission electron microscopic studies. The nitrogen sorption studies indicate that the specific surface areas, pore volume, pore diameter and pore size distribution of the mixed oxides were substantially enhanced when non-polar solvents such as toluene, p-xylene or mesitylene were added as co-solvents to the synthesis gel. Transmission electron microscopic (TEM) studies confirm the results obtained from the nitrogen sorption studies. Our results indicate that we can obtain binary metal oxides possessing high surface area and large pore volumes with tunable pore size distribution at room temperature. Photocatalytic evaluation of the mixed oxides is currently in progress.

  15. Hydrogen gas sensing feature of polyaniline/titania (rutile) nanocomposite at environmental conditions

    NASA Astrophysics Data System (ADS)

    Milani Moghaddam, Hossain; Nasirian, Shahruz

    2014-10-01

    The resistance-based sensors of polyaniline/titania (rutile) nanocomposite (TPNC) were prepared by spin coating technique onto an epoxy glass substrate with Cu-interdigited electrodes to study their hydrogen (H2) gas sensing features. Our findings are that the change of the surface morphology, porosity and wt% of titania in TPNCs have a significant effect on H2 gas sensing of sensors. All of the sensors had a reproducibility response toward 0.8 vol% H2 gas at room temperature, air pressure and 50% relative humidity. A sensor with 40 wt% of titania nanoparticles had better response/recovery time and the response than other sensors. Moreover, H2 gas sensing mechanism of TPNC sensors based contact areas and the correlation of energy levels between PANI chains and the titania grains were studied.

  16. Ternary ceramic thermal spraying powder and method of manufacturing thermal sprayed coating using said powder

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Vogli, Evelina; Sherman, Andrew J.; Glasgow, Curtis P.

    The invention describes a method for producing ternary and binary ceramic powders and their thermal spraying capable of manufacturing thermal sprayed coatings with superior properties. Powder contain at least 30% by weight ternary ceramic, at least 20% by weight binary molybdenum borides, at least one of the binary borides of Cr, Fe, Ni, W and Co and a maximum of 10% by weight of nano and submicro-sized boron nitride. The primary crystal phase of the manufactured thermal sprayed coatings from these powders is a ternary ceramic, while the secondary phases are binary ceramics. The coatings have extremely high resistance againstmore » corrosion of molten metal, extremely thermal shock resistance and superior tribological properties at low and at high temperatures.« less

  17. Synthesis and characterization of monosodium urate (MSU) nano particles

    NASA Astrophysics Data System (ADS)

    Tank, Nirali S.; Rathod, K. R.; Parekh, B. B.; Parikh, K. D.; Joshi, M. J.

    2016-05-01

    In Gout the deposition of crystals of Monosodium Urate (MSU) in various connective tissues and joints occurs, which is very painful with immflamation. The deposition likely to begin with nano particles form and expected to grow in to micro-paricles and hence it is important to synthesize and characrterize MSU nano-particles. The MSU nano particles were synthesized by wet chemical method using NaOH and uric acid (C5H4N4O3) and then characterized by powder XRD, TEM, FT-IR and thermal analysis. From the powder XRD the triclinic structure was found and 40 nm average particle size was estimated by using Scherrer's formula. From TEM the particle size was found to be in the range of 20 to 60 nm. The FT-IR spectrum for the MSU nano particles confirmed the presence of O-H stretching, N-H stretching, N-H rocking, C = O, C = C Enol or Keto and C = N vibrations. The thermal analysis was carried out from room temperature to 900°C. With comparison to the bulk MSU the thermal stability of MSU nano particles was slightly higher and 1.5 water molecules were found to be associated with MSU nano particles. Present results are compared with the bulk MSU.

  18. Bioelectrocatalytic application of titania nanotube array for molecule detection.

    PubMed

    Xie, Yibing; Zhou, Limin; Huang, Haitao

    2007-06-15

    A bioelectrocatalysis system based on titania nanotube electrode has been developed for the quantitative detection application. Highly ordered titania nanotube array with inner diameter of 60 nm and total length of 540 nm was formed by anodizing titanium foils. The functionalization modification was achieved by embedding glucose oxidases inside tubule channels and electropolymerizing pyrrole for interfacial immobilization. Morphology and microstructure characterization, electrochemical properties and bioelectrocatalytic reactivities of this composite were fully investigated. The direct detection of hydrogen peroxide by electrocatalytic reduction reaction was fulfilled on pure titania nanotube array with a detection limit up to 2.0 x 10(-4)mM. A biosensor based on the glucose oxidase-titania/titanium electrode was constructed for amperometric detection and quantitative determination of glucose in a phosphate buffer solution (pH 6.8) under a potentiostatic condition (-0.4V versus SCE). The resulting glucose biosensor showed an excellent performance with a response time below 5.6s and a detection limit of 2.0 x 10(-3)mM. The corresponding detection sensitivity was 45.5 microA mM(-1)cm(-2). A good operational reliability was also achieved with relative standard deviations below 3.0%. This novel biosensor exhibited quite high response sensitivity and low detection limit for potential applications.

  19. Anodically Grown Titania Nanotube Induced Cytotoxicity has Genotoxic Origins

    NASA Astrophysics Data System (ADS)

    Mohamed, M. Sheikh; Torabi, Aida; Paulose, Maggie; Kumar, D. Sakthi; Varghese, Oomman K.

    2017-02-01

    Nanoarchitectures of titania (TiO2) have been widely investigated for a number of medical applications including implants and drug delivery. Although titania is extensively used in the food, drug and cosmetic industries, biocompatibility of nanoscale titania is still under careful scrutiny due to the conflicting reports on its interaction with cellular matter. For an accurate insight, we performed in vitro studies on the response of human dermal fibroblast cells toward pristine titania nanotubes fabricated by anodic oxidation. The nanotubes at low concentrations were seen to induce toxicity to the cells, whereas at higher concentrations the cell vitality remained on par with controls. Further investigations revealed an increase in the G0 phase cell population depicting that majority of cells were in the resting rather than active phase. Though the mitochondrial set-up did not exhibit any signs of stress, significantly enhanced reactive oxygen species production in the nuclear compartment was noted. The TiO2 nanotubes were believed to have gained access to the nuclear machinery and caused increased stress leading to genotoxicity. This interesting property of the nanotubes could be utilized to kill cancer cells, especially if the nanotubes are functionalized for a specific target, thus eliminating the need for any chemotherapeutic agents.

  20. Experimental Investigation Nano Particles Influence in NPMEDM to Machine Inconel 800 with Electrolyte Copper Electrode

    NASA Astrophysics Data System (ADS)

    Karunakaran, K.; Chandrasekaran, M.

    2017-05-01

    The recent technology of machining hard materials is Powder mix dielectric electrical Discharge Machining (PMEDM). This research investigates nano sized (about 5Nm) powders influence in machining Inconel 800 nickel based super alloy. This work is motivated for a practical need for a manufacturing industry, which processes various kinds of jobs of Inconel 800 material. The conventional EDM machining also considered for investigation for the measure of Nano powders performances. The aluminum, silicon and multi walled Carbon Nano tubes powders were considered in this investigation along with pulse on time, pulse of time and input current to analyze and optimize the responses of Material Removal Rate, Tool Wear Rate and surface roughness. The Taguchi general Full Factorial Design was used to design the experiments. The most advance equipments employed in conducting experiments and measuring equipments to improve the accuracy of the result. The MWCNT powder mix was out performs than other powders which reduce 22% to 50% of the tool wear rate, gives the surface roughness reduction from 29.62% to 41.64% and improved MRR 42.91% to 53.51% than conventional EDM.

  1. Preparation and characterization of new photoluminescent nano-powder based on Eu3+:La2Ti2O7 and dispersed into silica matrix for latent fingerprint detection

    NASA Astrophysics Data System (ADS)

    Saif, M.; Alsayed, N.; Mbarek, A.; El-Kemary, M.; Abdel-Mottaleb, M. S. A.

    2016-12-01

    Pure lanthanum titanate doped with europium metal ions (La2Ti2O7:Eu3+) and dispersed in silica matrix phosphor powder was prepared by sol-gel process followed by thermal treatment. The prepared nanophosphors were characterized by powder X-ray Diffraction (XRD), Fourier Transform Infrared (FT-IR), Transmission Electron Microscope (TEM), Energy Dispersive Spectroscopy (EDX), and Photoluminescence Spectroscopy (PL). The effects of silica, thermal treatment, Eu3+ ion, and surfactant (CTAB) concentrations on the crystal, morphology, and photoluminescence properties were investigated. The present work found that dispersion of La2Ti2O7:Eu3+ into silica matrix significantly altered the morphology of La2Ti2O7:Eu3+ from high crystalline micro-plate like shape into amorphous aggregated Nano-spherical shape. The high separated spherical shape with intense red PL emission and long lifetime was obtained from 10 mol% Eu3+:La2Ti2O7:Eu3+, dispersed into silica matrix, and prepared in the presence of CTAB. The high PL Nano-phosphor has been successfully used in developing latent fingerprint from various forensic relevant materials.

  2. Titania High-Resolution Color Composite

    NASA Image and Video Library

    1996-01-29

    This high-resolution color composite of Titania was made from NASA Voyager 2 images taken Jan. 24, 1986, as the spacecraft neared its closest approach to Uranus. A large, trenchlike feature is seen near the terminator. http://photojournal.jpl.nasa.gov/catalog/PIA00036

  3. The Effect of Titanium Tetrahedral Coordination of Silica-Titania Catalyst on the Physical Properties of Biodiesel

    NASA Astrophysics Data System (ADS)

    Nizar, U. K.; Hidayatul, J.; Sundari, R.; Bahrizal, B.; Amran, A.; Putra, A.; Latisma DJ, L.; Dewata, I.

    2018-04-01

    This study investigates the correlation of the number of titanium tetrahedral coordination and biodiesel production. The solid-state method has been used to synthesis of silica-titania catalyst for biodiesel production, which the precursors, i.e. silica and titania commercials were heated in the temperature range of 450 - 550°C. The characterization of the prepared silica-titania has been studied by FTIR and DR UV-Vis in order to identify and calculate the presence of titanium tetrahedral coordination in silica-titania catalyst. A very small peak at around 950 cm-1 indicated the presence of titanium tetrahedral coordination through Si–O–Ti bonds. Deconvolution of DR UV-Vis spectra showed the coordination of titanium in silica-titania is more octahedral. However, the number of titanium tetrahedral coordination of the prepared silica-titania is found higher than that of TiO2 commercial. The increasing of titanium tetrahedral fraction in silica-titania affects the physical properties of biodiesel in terms of boiling point, viscosity and density, which is produced by the reaction of methanol and palm oil.

  4. Effect of calcination temperature on the lithiation capacities of carbon-coated titania nanotubes synthesized by anodization

    NASA Astrophysics Data System (ADS)

    Seo, Min-Su; Lee, Hyukjae

    2012-06-01

    Carbon-coated titania nanotubes are synthesized via anodization in perchlorate containing electrolyte and subsequent hydrothermal reaction with glucose. Carbon coating improves the lithiation capacity of the titania nanotubes only when calcined at temperatures above 600°C, and the maximum capacity is ˜162 mAhg-1 at the 50th cycle from the titania nanotubes calcined at 700°C. The improved capacity of carbon-coated titania nanotubes is caused by the enhanced conductivity from the carbon. This is different from the role of the carbon coating in the hydrothermally prepared carbon-coated titania nanotubes, in which the coated carbon limits severe agglomeration.

  5. CHARACTERIZATION OF FLAME-SYNTHESIZED FE, CO, OR MN-DOPED TITANIA NANOSTRUCTURED PARTICLES

    EPA Science Inventory

    The flame-synthesized catalysts have higher surface areas than commercial-grade titania and are composed of nanometer-sized primary particles with low internal porosity. Preliminary studies suggest that flame-synthesized iron-doped titania may be photoactivated in the visible lig...

  6. Band Gap Engineering of Titania Systems Purposed for Photocatalytic Activity

    NASA Astrophysics Data System (ADS)

    Thurston, Cameron

    Ab initio computer aided design drastically increases candidate population for highly specified material discovery and selection. These simulations, carried out through a first-principles computational approach, accurately extrapolate material properties and behavior. Titanium Dioxide (TiO2 ) is one such material that stands to gain a great deal from the use of these simulations. In its anatase form, titania (TiO2 ) has been found to exhibit a band gap nearing 3.2 eV. If titania is to become a viable alternative to other contemporary photoactive materials exhibiting band gaps better suited for the solar spectrum, then the band gap must be subsequently reduced. To lower the energy needed for electronic excitation, both transition metals and non-metals have been extensively researched and are currently viable candidates for the continued reduction of titania's band gap. The introduction of multicomponent atomic doping introduces new energy bands which tend to both reduce the band gap and recombination loss. Ta-N, Nb-N, V-N, Cr-N, Mo-N, and W-N substitutions were studied in titania and subsequent energy and band gap calculations show a favorable band gap reduction in the case of passivated systems.

  7. Synthesis, characterization and color performance of novel Co²+-doped alumina/titania nanoceramic pigments.

    PubMed

    Hafez, Hoda S; El-Fadaly, E

    2012-09-01

    Blue-green nanoceramic pigments from Co(2+)-doped alumina-titania (xCo(2+)-Al(2)O(3)/TiO(2)) have been synthesized by alkoxide sol-gel route from a mixture of titania and boehmite sols that derived from titanium isopropoxide and aluminum nitrate precursors. The composition of the alumina/titania (AT) matrix is 3:1M ratio. A series of xCo(2+):3TiO(2):1Al(2)O(3) mixed oxides with different Co(2+)-dopant ion concentration has been prepared. The molar ratio of the Co(2+)-dopant ion in the Al(2)O(3)/TiO(2) matrix is from x=0 to 0.5M ratio relative to the titania composition. Characterizations of Co(2+)-doped alumina/titania nanocomposites are carried out using reflectance spectroscopy, transmission electron microscope (TEM), scanning electron microscopy (SEM-EDS), thermo-gravimetric analysis (TGA) and X-ray diffractometer (XRD). The experimental results demonstrated that the prepared Co(2+)-doped alumina-titania nanocomposites fulfill the current technological requirements for ceramic pigment applications that exhibit a high physico-chemical and thermal stabilities at high firing temperatures. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Sustainable steric stabilization of colloidal titania nanoparticles

    NASA Astrophysics Data System (ADS)

    Elbasuney, Sherif

    2017-07-01

    A route to produce a stable colloidal suspension is essential if mono-dispersed particles are to be successfully synthesized, isolated, and used in subsequent nanocomposite manufacture. Dispersing nanoparticles in fluids was found to be an important approach for avoiding poor dispersion characteristics. However, there is still a great tendency for colloidal nanoparticles to flocculate over time. Steric stabilization can prevent coagulation by introducing a thick adsorbed organic layer which constitutes a significant steric barrier that can prevent the particle surfaces from coming into direct contact. One of the main features of hydrothermal synthesis technique is that it offers novel approaches for sustainable nanoparticle surface modification. This manuscript reports on the sustainable steric stabilization of titanium dioxide nanoparticles. Nanoparticle surface modification was performed via two main approaches including post-synthesis and in situ surface modification. The tuneable hydrothermal conditions (i.e. temperature, pressure, flow rates, and surfactant addition) were optimized to enable controlled steric stabilization in a continuous fashion. Effective post synthesis surface modification with organic ligand (dodecenyl succinic anhydride (DDSA)) was achieved; the optimum surface coating temperature was reported to be 180-240 °C to ensure DDSA ring opening and binding to titania nanoparticles. Organic-modified titania demonstrated complete change in surface properties from hydrophilic to hydrophobic and exhibited phase transfer from the aqueous phase to the organic phase. Exclusive surface modification in the reactor was found to be an effective approach; it demonstrated surfactant loading level 2.2 times that of post synthesis surface modification. Titania was also stabilized in aqueous media using poly acrylic acid (PAA) as polar polymeric dispersant. PAA-titania nanoparticles demonstrated a durable amorphous polymeric layer of 2 nm thickness. This

  9. Research on surface modification of nano-zirconia

    NASA Astrophysics Data System (ADS)

    Chen, Wen; Zhang, Cun-Lin; Yang, Xiao-Yi

    2005-02-01

    The mechanisms about the aggregation and dispersibility of nano-zirconia were analyzed in detail. And nano-zirconia powders which were surface-modified with silane coupling reagent WD70 were prepared in order to disperse homogeneously in ethanol in this investigation. The grain size and grain phase of nano-zirconia were obtained by XRD. Research and characterization on the structure and surface characteristic of surface-modified nano-zirconia were achieved by XPS, TG-DSC, TEM and FT-IR. The results given by FT-IR and XPS showed WD70 was jointed on the surface of nano-zirconia through both physical adsorption and chemical binding after the de-methanol reaction between the methoxyl groups of WD70 and the hydroxy groups on the surface of nano-zirconia. And the corresponding model of surface-modified nano-zirconia was given. The images provided by TEM presented intuitionistic effect of surface modification on the dispersibility of nano-zirconia in ethanol. And TG-DSC analysis ascertained the amount of WD70 that was jointed on the surface of nano-zirconia and the amount was about 6.21 percent.

  10. Effect of nano-titanium dioxide on mechanical and electrical properties and microstructure of reactive powder concrete

    NASA Astrophysics Data System (ADS)

    Li, Zhen; Han, Baoguo; Yu, Xun; Dong, Sufen; Zhang, Liqing; Dong, Xufeng; Ou, Jinping

    2017-09-01

    Nano-titanium dioxide (NT) was introduced into reactive powder concrete (RPC) to prepare NT reinforced RPC (NTRRPC) in this study. The mechanical and electrical properties and microstructure of NTRRPC were investigated. Research results indicate that NT can accelerate the hydration of RPC at early ages due to its nucleation effect. Cement hydration degree is free from the inclusion of NT at the curing age of 28 d. However, x-ray powder diffraction (XRD) analysis and scanning electron microscope (SEM) observation confirm that the nucleation effect of NT not only can reduce the orientation degree of calcium hydroxide (CH), but also can restrict the size of CH. Hence, NT may also benefit to enhance the strength at late age. The flexural and compressive strengths of NTRRPC at age of 28 d achieve increases of 47.07% (relative increase rate)/3.62 MPa (the absolute increase) and 18.05%/18.42 MPa with respect to the control RPC, respectively. The compactedness model demonstrates that NT can improve the compactedness of RPC and reduce the porosity of RPC from 9.04% to 6.96%. SEM observations suggest that the NT can refine the pores and micro cracks of the RPC by its filling effect, which is in accordance with the result of compactedness model. In addition, the addition of NT can improve the electrically conductivity property of RPC and make a 13.61% decrease in the electrical resistivity of RPC.

  11. Morphological Characterization Of Titania Slag Obtained From Red Sediment Placer Ilmenite Using Microwave Energy

    NASA Astrophysics Data System (ADS)

    Srikant, S. S.; Mukherjee, P. S.; Bhima Rao, R.

    2015-04-01

    This paper deals with the main objective to observe the effect of microwave heat treatment for the production of Titania rich slag and pig iron from placer ilmenite. The experiments carried out in the present investigation on the oxidized ilmenite sample for microwave heat treatment in microwave sintering furnace reveals that a product can be obtained containing Titania rich slag and metalized iron. The in-depth characterisation of these products using SEM-EDAX shows that around 75-85 % of titanium dioxide is formed in terms of titania rich slag by using microwave sintering furnace after reduction of oxidized ilmenite with proper stoichiometric graphitic carbon and silicon carbide (SiC) susceptor. The titania rich slag is considered to be better input material for production of pigment grade titanium dioxide. On the other hand, the pig iron obtained as by product from titania rich slag is also important for automobile and steel industries application.

  12. Vibrational Spectroscopic Studies on the Formation of Ion-exchangeable Titania Nanotubes

    NASA Astrophysics Data System (ADS)

    Hodos, Mária; Haspel, Henrik; Horváth, Endre; Kukovecz, Ákos; Kónya, Zoltán; Kiricsi, Imre

    2005-09-01

    Ion-exchangeable titanium-oxide nanotubes have commanded considerable interest from the materials science community in the past five years. Synthesized under hydrothermal conditions from TiO2, typical nanotubes are 150-200 nm long and 8-20 nm wide. High resolution TEM images revealed that unlike multiwall carbon nanotubes which are made of coaxial single-wall nanotubes, the titania tubes possess a spiral cross-section. An interesting feature of the titania tubes is their considerable ion-exchange capacity which could be utilized e.g. for enhancing their photocatalytic activity by doping the titania tubes with CdS nanoparticles. In this contribution we present a comprehensive TEM, FT-Raman and FT-farIR characterization study of the formation process.

  13. New insights into respirable protein powder preparation using a nano spray dryer.

    PubMed

    Bürki, K; Jeon, I; Arpagaus, C; Betz, G

    2011-04-15

    In this study the Nano Spray Dryer B-90 (BÜCHI Labortechnik AG, Flawil, Switzerland) was evaluated with regard to the drying of proteins and the preparation of respirable powders in the size range of 1-5 μm. β-galactosidase was chosen as a model protein and trehalose was added as a stabilizer. The influence of inlet temperature, hole size of the spray cap membrane and ethanol concentration in the spray solution was studied using a 3³ full factorial design. The investigated responses were enzyme activity, particle size, span, yield and shelf life. Furthermore, the particle morphology was examined. The inlet temperature as well as the interaction of inlet temperature and spray cap size significantly influenced the enzyme activity. Full activity was retained with the optimized process. The particle size was affected by the hole size of the spray cap membrane and the ethanol content. The smallest cap led to a monodisperse particle size distribution and the greatest yield of particles of respirable size. Higher product recovery was achieved with lower inlet temperatures, higher ethanol contents and smaller cap sizes. Particle morphology differed depending on the cap size. The protein exhibited higher storage stability when spray dried without ethanol and when a larger spray cap size was used. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. Synthesis and characterization of nanocrystalline Nd{sup 3+}-doped gadolinium scandium aluminum garnet powders by a gel-combustion method

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Su, Jing, E-mail: zlj007@126.com; Miao, Ju-hong; Xu, Lin-hua

    2012-07-15

    Graphical abstract: The graph shows the emission spectra (λ{sub ex} = 808 nm) of 1 at.% Nd:GSAG powders sintered at different temperatures for 3 h. Compared with the powder sintered at 900 °C, the PL intensity of the powder sintered at 1000 °C decreased significantly. The changes in the PL intensity should mainly due to the crystallinity and dispersion of the powders. Highlights: ► We synthesized Nd:GSAG nano-powders by gel-combustion method successfully. ► We analyzed the structure and the morphology of the heat-treated products. ► We studied the optical characteristics of Nd:GSAG nano-powders. -- Abstract: Nd{sup 3+}-doped gadolinium scandium aluminummore » garnet (Nd:GSAG) precursor was synthesized by a gel combustion method using metal nitrates and citric acid as raw materials. The structure and morphology of the precursor and the sintered powders were studied by means of X-ray diffraction (XRD), infrared spectroscopy (IR) and transmission electron microscopy (TEM). The results showed that the precursor transformed into pure GSAG polycrystalline phase at about 800 °C, and the powders sintered at 800–1000 °C were well-dispersed with average particle sizes in the range of 30–80 nm. Optical properties of Nd:GSAG nano-powders were characterized by using photoluminescence spectroscopy. The highest photoluminescence intensity was achieved for the powder sintered at 900 °C.« less

  15. Solvothermal-induced phase transition and visible photocatalytic activity of nitrogen-doped titania.

    PubMed

    Liu, Jianjun; Qin, Wei; Zuo, Shengli; Yu, Yingchun; Hao, Zhengping

    2009-04-15

    Nitrogen-doped titania nanoparticles consisting of pure anatase, pure rutile and bicrystallites (anatase+rutile and anatase+brookite) have been prepared in TiCl(3)-HMT (hexamethylene tetramine)-alcohol solution under solvothermal process. The effect of the solvent type and amount of HMT as pH adjuster on the phase composition of titania and its visible photocatalytic activity for degradation to MO (methyl orange) was investigated. It is found that anatase gradually transferred to rutile with increase of carbon chain using methanol, ethanol, 1-propanol and 1-butanol as solvent. The pure anatase formed at the pH value of 1-2, while bicrystalline titania (anatase+rutile and anatase+brookite) at that of 7-10 in the presence of methanol. The bicrystalline (anatase+brookite) titania have the best visible photocatalytic activity among all the samples. The -(NO) and -(NH) dopants with an N (1s) binding energy of 400 eV may have positive effects on the visible light photocatalytic activity.

  16. Structural Characterization and Corrosion Behavior of Stainless Steel Coated With Sol-Gel Titania

    NASA Astrophysics Data System (ADS)

    Vasconcelos, Daniela C. L.; Nunes, Eduardo H. M.; Sabioni, Antônio Claret S.; da Costa, João C. Diniz; Vasconcelos, Wander L.

    2012-03-01

    Sol-gel titania films were prepared from hydrolysis and condensation of titanium (IV) isopropoxide. Diethanolamine was used as chelant agent in titania synthesis. 316L stainless steel substrates were dip-coated at three different withdrawal speeds (6, 30, and 60 mm/min) and heated up to 400 °C. Thermogravimetry and differential thermal analyses of the titania gel solution evinced a continuous mass loss for temperatures up to 800 °C. The transition of anatase to the rutile phase begins at 610-650 °C, being the rutile transformation completed at 900 °C. The thicknesses of the films were determined as a function of the heat treatment and withdrawal speed. It was observed that their thicknesses varied from 130 to 770 nm. Scanning electron microscopy images of the composites revealed the glass-like microstructure of the films. The obtained sol-gel films were also characterized by energy dispersive spectroscopy. The chemical evolution of the films as a function of the heating temperature was evaluated by Fourier transform infrared spectroscopy (specular reflectance method). After performing the adhesion tests, the adherence of the titania films to the stainless steel substrate was excellent, rated 5B according to ASTM 3359. The hardness of the ceramic films obtained was measured by the Knoop microindentation hardness test with a 10 g load. We observed that the titania film became harder than the steel substrate when it was heated above 400 °C. The corrosion rates of the titania/steel composites, determined from potentiodynamic curves, were two orders of magnitude lower than that of the bare stainless steel. The presence of the sol-gel titania film contributed to the increase of the corrosion potential in ca. 650 mV and the passivation potential in ca. 720 mV.

  17. Constructing Black Titania with Unique Nanocage Structure for Solar Desalination.

    PubMed

    Zhu, Guilian; Xu, Jijian; Zhao, Wenli; Huang, Fuqiang

    2016-11-23

    Solar desalination driven by solar radiation as heat source is freely available, however, hindered by low efficiency. Herein, we first design and synthesize black titania with a unique nanocage structure simultaneously with light trapping effect to enhance light harvesting, well-crystallized interconnected nanograins to accelerate the heat transfer from titania to water and with opening mesopores (4-10 nm) to facilitate the permeation of water vapor. Furthermore, the coated self-floating black titania nanocages film localizes the temperature increase at the water-air interface rather than uniformly heating the bulk of the water, which ultimately results in a solar-thermal conversion efficiency as high as 70.9% under a simulated solar light with an intensity of 1 kW m -2 (1 sun). This finding should inspire new black materials with rationally designed structure for superior solar desalination performance.

  18. Synthesis and characterization of CdO nano particles by the sol-gel method

    NASA Astrophysics Data System (ADS)

    Vadgama, V. S.; Vyas, R. P.; Jogiya, B. V.; Joshi, M. J.

    2017-05-01

    Cadmium Oxide (CdO) is an inorganic compound and one of the main precursors to other cadmium compounds. It finds applications in cadmium plating, storage batteries, in transparent conducting film, etc. Here, an attempt is made to synthesize CdO nano particles by sol-gel technique. The gel was prepared using cadmium nitrate tetra hydrate (Cd(NO3)2.4H2O) and aqueous ammonium hydroxide (NH4OH) as a precursor. The synthesized powder is further characterized by techniques like Powder X-ray diffraction (XRD), Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and Thermal gravimetric analysis (TGA). Powder XRD analysis suggested the nano-crystalline nature of the sample with the cubic crystal system. Nano scaled particles of spherical morphology with the size ranging from 50-100 nm are observed from TEM images. While, FT-IR study is used to confirm the presence of different functional groups. Thermo-gravimetric analysis suggests the highly thermally stable nature of the samples. The results are discussed.

  19. Thermal Stability of Milled Nanocrystalline Tungsten Powders

    DTIC Science & Technology

    2011-05-01

    v Acknowledgments This research is supported by mission funding from the Depleted Uranium Replacement Program and is the result of collaborative...L.; Reddy, R. G. Synthesis of Titanium Carbide Nano-powders by Thermal Plasma. Scripta Materialia 2005, 52 (12), 1253–1258. 4. Karagedov, G. R

  20. Lithium ion batteries with titania/graphene anodes

    DOEpatents

    Liu, Jun; Choi, Daiwon; Yang, Zhenguo; Wang, Donghai; Graff, Gordon L; Nie, Zimin; Viswanathan, Vilayanur V; Zhang, Jason; Xu, Wu; Kim, Jin Yong

    2013-05-28

    Lithium ion batteries having an anode comprising at least one graphene layer in electrical communication with titania to form a nanocomposite material, a cathode comprising a lithium olivine structure, and an electrolyte. The graphene layer has a carbon to oxygen ratio of between 15 to 1 and 500 to 1 and a surface area of between 400 and 2630 m.sup.2/g. The nanocomposite material has a specific capacity at least twice that of a titania material without graphene material at a charge/discharge rate greater than about 10 C. The olivine structure of the cathode of the lithium ion battery of the present invention is LiMPO.sub.4 where M is selected from the group consisting of Fe, Mn, Co, Ni and combinations thereof.

  1. Enhanced antibactericidal function of W4+-doped titania-coated nickel ferrite composite nanoparticles: a biomaterial system.

    PubMed

    Sunkara, B K; Misra, R D K

    2008-03-01

    The study demonstrates a distinct enhancement of antimicrobial activity of W4+-doped titania that is coated on nickel ferrite nanoparticles in comparison to undoped titania. The composite nanoparticles were synthesized by uniquely combining reverse micelle and chemical hydrolysis synthesis methods [Rana S, Rawat J, Misra RDK, Acta Biomater 2005;1:691]. The superior antimicrobial activity of W4+-doped titania is related to the inhibition of electron-hole recombination and decrease in the band gap energy of titania. The function of the ferrite is to facilitate the removal of nanoparticles from the sprayed surface using a small magnetic field. The coating of ferrite nanoparticles with titania retains superparamagnetic character and magnetic strength of composite nanoparticles signifying non-deterioration of magnetic properties and promoting their use as removable antimicrobial photocatalyst nanoparticles.

  2. Tin-Platinum catalysts interactions on titania and silica

    NASA Astrophysics Data System (ADS)

    Nava, N.; Del Angel, P.; Salmones, J.; Baggio-Saitovitch, E.; Santiago, P.

    2007-09-01

    Pt-Sn was supported on titania and silica, and the resulting interactions between the components in prepared samples and the resulting interactions between the components before and after treatment with hydrogen were characterized by Mössbauer spectroscopy, X-ray diffraction, Rietveld refinement, high-resolution transmission electron microscopy (HRTEM) and catalytic tests data. Results show the presence of Pt and SnO 2 after calcinations, and Pt 3Sn, PtSn and PtSn 3 after reduction. Rietveld analysis shows that some Ti 4+ are replaced by Sn 4+ atoms in the titania structure. Finally, HRTEM and the practically absence of activity observed confirms that metallic platinum is encapsulated.

  3. MC3T3-E1 osteoblast attachment and proliferation on porous hydroxyapatite scaffolds fabricated with nanophase powder

    PubMed Central

    Smith, Ian O; McCabe, Laura R; Baumann, Melissa J

    2006-01-01

    Porous bone tissue engineering scaffolds were fabricated using both nano hydroxyapatite (nano HA) powder (20 nm average particle size) and micro HA powder (10 μm average particle size), resulting in sintered scaffolds of 59 vol% porosity and 8.6±1.9 μm average grain size and 72 vol% porosity and 588±55 nm average grain size, respectively. Scanning electron microscopy was used to measure both the grain size and pore size. MC3T3-E1 osteoblast (OB) attachment and proliferation on both nano HA and micro HA porous scaffolds were quantified. As expected, OB cell number was greater on nano HA scaffolds compared with similarly processed micro HA scaffolds 5 days after seeding, while OB attachment did not appear greater on the nano HA scaffolds (p<0.05). PMID:17722535

  4. Performance enhancement of direct ethanol fuel cell using Nafion composites with high volume fraction of titania

    NASA Astrophysics Data System (ADS)

    Matos, B. R.; Isidoro, R. A.; Santiago, E. I.; Fonseca, F. C.

    2014-12-01

    The present study reports on the performance enhancement of direct ethanol fuel cell (DEFC) at 130 °C with Nafion-titania composite electrolytes prepared by sol-gel technique and containing high volume fractions of the ceramic phase. It is found that for high volume fractions of titania (>10 vol%) the ethanol uptake of composites is largely reduced while the proton conductivity at high-temperatures is weakly dependent on the titania content. Such tradeoff between alcohol uptake and conductivity resulted in a boost of DEFC performance at high temperatures using Nafion-titania composites with high fraction of the inorganic phase.

  5. In vivo demonstration of enhanced radiotherapy using rare earth doped titania nanoparticles†

    PubMed Central

    Townley, Helen E.; Kim, Jeewon; Dobson, Peter J.

    2017-01-01

    Radiation therapy is often limited by damage to healthy tissue and associated side-effects; restricting radiation to ineffective doses. Preferential incorporation of materials into tumour tissue can enhance the effect of radiation. Titania has precedent for use in photodynamic therapy (PDT), generating reactive oxygen species (ROS) upon photoexcitation, but is limited by the penetration depth of UV light. Optimization of a nanomaterial for interaction with X-rays could be used for deep tumour treatment. As such, titania nanoparticles were doped with gadolinium to optimize the localized energy absorption from a conventional medical X-ray, and further optimized by the addition of other rare earth (RE) elements. These elements were selected due to their large X-ray photon interaction cross-section, and potential for integration into the titania crystal structure. Specific activation of the nanoparticles by X-ray can result in generation of ROS leading to cell death in a tumour-localized manner. We show here that intratumoural injection of RE doped titania nanoparticles can enhance the efficacy of radiotherapy in vivo. PMID:22767269

  6. In vivo demonstration of enhanced radiotherapy using rare earth doped titania nanoparticles.

    PubMed

    Townley, Helen E; Kim, Jeewon; Dobson, Peter J

    2012-08-21

    Radiation therapy is often limited by damage to healthy tissue and associated side-effects; restricting radiation to ineffective doses. Preferential incorporation of materials into tumour tissue can enhance the effect of radiation. Titania has precedent for use in photodynamic therapy (PDT), generating reactive oxygen species (ROS) upon photoexcitation, but is limited by the penetration depth of UV light. Optimization of a nanomaterial for interaction with X-rays could be used for deep tumour treatment. As such, titania nanoparticles were doped with gadolinium to optimize the localized energy absorption from a conventional medical X-ray, and further optimized by the addition of other rare earth (RE) elements. These elements were selected due to their large X-ray photon interaction cross-section, and potential for integration into the titania crystal structure. Specific activation of the nanoparticles by X-ray can result in generation of ROS leading to cell death in a tumour-localized manner. We show here that intratumoural injection of RE doped titania nanoparticles can enhance the efficacy of radiotherapy in vivo.

  7. Mixed conductivity, structural and microstructural characterization of titania-doped yttria tetragonal zirconia polycrystalline/titania-doped yttria stabilized zirconia composite anode matrices

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Colomer, M.T., E-mail: tcolomer@icv.csic.e; Maczka, M.

    2011-02-15

    Taking advantage of the fact that TiO{sub 2} additions to 8YSZ cause not only the formation of a titania-doped YSZ solid solution but also a titania-doped YTZP solid solution, composite materials based on both solutions were prepared by solid state reaction. In particular, additions of 15 mol% of TiO{sub 2} give rise to composite materials constituted by 0.51 mol fraction titania-doped yttria tetragonal zirconia polycrystalline and 0.49 mol fraction titania-doped yttria stabilized zirconia (0.51TiYTZP/0.49TiYSZ). Furthermore, Y{sub 2}(Ti{sub 1-y}Zr{sub y}){sub 2}O{sub 7} pyrochlore is present as an impurity phase with y close to 1, according to FT-Raman results. Lower and highermore » additions of titania than that of 15 mol%, i.e., x=0, 5, 10, 20, 25 and 30 mol% were considered to study the evolution of 8YSZ phase as a function of the TiO{sub 2} content. Furthermore, zirconium titanate phase (ZrTiO{sub 4}) is detected when the titania content is equal or higher than 20 mol% and this phase admits Y{sub 2}O{sub 3} in solid solution according to FE-SEM-EDX. The 0.51TiYTZP/0.49TiYSZ duplex material was selected in this study to establish the mechanism of its electronic conduction under low oxygen partial pressures. In the pO{sub 2} range from 0.21 to 10{sup -7.5} atm. the conductivity is predominantly ionic and constant over the range and its value is 0.01 S/cm. The ionic plus electronic conductivity is 0.02 S/cm at 1000 {sup o}C and 10{sup -12.3} atm. Furthermore, the onset of electronic conductivity under reducing conditions exhibits a -1/4 pO{sub 2} dependence. Therefore, it is concluded that the n-type electronic conduction in the duplex material can be due to a small polaron-hopping between Ti{sup 3+} and Ti{sup 4+}. -- Graphical abstract: FE-SEM micrograph of a polished and thermal etched surface of a Ti-doped YTZP/Ti-doped YSZ composite material. Display Omitted Research highlights: {yields} Ti-doped YTZP/Ti-doped YSZ composite materials are mixed conductors

  8. Electrolytic Reduction of Titania Slag in Molten Calcium Chloride Bath

    NASA Astrophysics Data System (ADS)

    Mohanty, Jayashree

    2012-05-01

    Ferro-titanium is prepared by direct electrolytic reduction of titania-rich slag obtained from plasma smelting of ilmenite in molten CaCl2. The product after electro-reduction is characterized by x-ray diffraction, scanning electron microscopy, and electron probe microanalysis. The electrolysis is carried out at a cell voltage of 3.0 V, taking graphite as the electrolysis cell as well as the anode, and a titania-rich slag piece wrapped by a nichrome wire is used as the cathode.

  9. Microstructure, crystallization and shape memory behavior of titania and yttria co-doped zirconia

    DOE PAGES

    Zeng, Xiao Mei; Du, Zehui; Schuh, Christopher A.; ...

    2015-12-17

    Small volume zirconia ceramics with few or no grain boundaries have been demonstrated recently to exhibit the shape memory effect. To explore the shape memory properties of yttria doped zirconia (YDZ), it is desirable to develop large, microscale grains, instead of submicron grains that result from typical processing of YDZ. In this paper, we have successfully produced single crystal micro-pillars from microscale grains encouraged by the addition of titania during processing. Titania has been doped into YDZ ceramics and its effect on the grain growth, crystallization and microscale elemental distribution of the ceramics have been systematically studied. With 5 mol%more » titania doping, the grain size can be increased up to ~4 μm, while retaining a large quantity of the desired tetragonal phase of zirconia. Finally, micro-pillars machined from tetragonal grains exhibit the expected shape memory effects where pillars made from titania-free YDZ would not.« less

  10. Synthesis of Titania-supported Copper Nanoparticles via Refined Alkoxide Sol-gel Process

    NASA Astrophysics Data System (ADS)

    Wu, Jeffrey C. S.; Tseng, I.-Hsiang; Chang, Wan-Chen

    2001-06-01

    Nanoparticles of titania and copper-loaded titania were synthesized by a refined sol-gel method using titanium butoxide. Unlike the conventional sol-gel procedure of adding water directly, the esterification of anhydrous butanol and glacial acetic acid provided the hydrolyzing water. In addition, acetic acid also served as a chelating ligand to stabilize the hydrolysis-condensation process and minimize the agglomeration of titania. Following the hydrolysis, Cu/TiO2 was prepared by adding copper chloride to titania sol. The sol was dried, then calcined at 500°C to remove organics and transformed to anatase titania which was verified by XRD. Cu/TiO2 was further hydrogen-reduced at 300°C. The recovery of Ti was exceeded by an average of 95% from titanium butoxide. TEM micrographs show that the Cu/TiO2 particles are near uniform. The average crystallite sizes are 17-20 nm estimated from the peak broadening of XRD spectra. The bandgaps of TiO2 and reduced Cu/TiO2 range from 2.70 to 3.15 eV estimated from the diffusive reflective UV-Vis spectra. XPS analysis shows that Cu 2p3/2 is 933.4 eV indicating primary Cu2O form on the TiO2 supports. The binding energy of Ti does not exhibit chemical shift suggesting negligible interaction of Cu cluster and TiO2 support.

  11. High Temperature Mechanical Behavior of Polycrystalline Alumina from Mixed Nanometer and Micrometer Powders

    NASA Technical Reports Server (NTRS)

    Goldsby, Jon C.

    2001-01-01

    Sintered aluminum oxide materials were formed using commercial methods from mechanically mixed powders of nano-and micrometer alumina. The powders were consolidated at 1500 and 1600 C with 3.2 and 7.2 ksi applied stress in argon. The conventional micrometer sized powders failed to consolidate. While 100 percent nanometer-sized alumina and its mixture with the micrometer powders achieved less than 99 percent density. Preliminary high temperature creep behavior indicates no super-plastic strains. However high strains (less than 0.65 percent) were generated in the nanometer powder, due to cracks and linked voids initiated by cavitation.

  12. Nano-sized Mo- and Nb-doped TiO2 as anode materials for high energy and high power hybrid Li-ion capacitors.

    PubMed

    Bauer, Dustin; Roberts, Alexander J; Matsumi, Noriyoshi; Darr, Jawwad A

    2017-05-12

    Nano-sized Mo-doped titania (Mo 0.1 Ti 0.9 O 2 ) and Nb-doped titania (Nb 0.25 Ti 0.75 O 2 ) were directly synthesized via a continuous hydrothermal flow synthesis process. Materials characterization was conducted using physical techniques such as transmission electron microscopy, powder x-ray diffraction, x-ray photoelectron spectroscopy, Brunauer-Emmett-Teller specific surface area measurements and energy dispersive x-ray spectroscopy. Hybrid Li-ion supercapacitors were made with either a Mo-doped or Nb-doped TiO 2 negative electrode material and an activated carbon (AC) positive electrode. Cells were evaluated using electrochemical testing (cyclic voltammetry, constant charge discharge cycling). The hybrid Li-ion capacitors showed good energy densities at moderate power densities. When cycled in the potential window 0.5-3.0 V, the Mo 0.1 Ti 0.9 O 2 /AC hybrid supercapacitor showed the highest energy densities of 51 Wh kg -1 at a power of 180 W kg -1 with energy densities rapidly declining with increasing applied specific current. In comparison, the Nb 0.25 Ti 0.75 O 2 /AC hybrid supercapacitor maintained its energy density of 45 Wh kg -1 at 180 W kg -1 better, showing 36 Wh g -1 at 3200 W kg -1 , which is a very promising mix of high energy and power densities. Reducing the voltage window to the range 1.0-3.0 V led to an increase in power density, with the Mo 0.1 Ti 0.9 O 2 /AC hybrid supercapacitor giving energy densities of 12 Wh kg -1 and 2.5 Wh kg -1 at power densities of 6700 W kg -1 and 14 000 W kg -1 , respectively.

  13. Nano-sized Mo- and Nb-doped TiO2 as anode materials for high energy and high power hybrid Li-ion capacitors

    NASA Astrophysics Data System (ADS)

    Bauer, Dustin; Roberts, Alexander J.; Matsumi, Noriyoshi; Darr, Jawwad A.

    2017-05-01

    Nano-sized Mo-doped titania (Mo0.1Ti0.9O2) and Nb-doped titania (Nb0.25Ti0.75O2) were directly synthesized via a continuous hydrothermal flow synthesis process. Materials characterization was conducted using physical techniques such as transmission electron microscopy, powder x-ray diffraction, x-ray photoelectron spectroscopy, Brunauer-Emmett-Teller specific surface area measurements and energy dispersive x-ray spectroscopy. Hybrid Li-ion supercapacitors were made with either a Mo-doped or Nb-doped TiO2 negative electrode material and an activated carbon (AC) positive electrode. Cells were evaluated using electrochemical testing (cyclic voltammetry, constant charge discharge cycling). The hybrid Li-ion capacitors showed good energy densities at moderate power densities. When cycled in the potential window 0.5-3.0 V, the Mo0.1Ti0.9O2/AC hybrid supercapacitor showed the highest energy densities of 51 Wh kg-1 at a power of 180 W kg-1 with energy densities rapidly declining with increasing applied specific current. In comparison, the Nb0.25Ti0.75O2/AC hybrid supercapacitor maintained its energy density of 45 Wh kg-1 at 180 W kg-1 better, showing 36 Wh g-1 at 3200 W kg-1, which is a very promising mix of high energy and power densities. Reducing the voltage window to the range 1.0-3.0 V led to an increase in power density, with the Mo0.1Ti0.9O2/AC hybrid supercapacitor giving energy densities of 12 Wh kg-1 and 2.5 Wh kg-1 at power densities of 6700 W kg-1 and 14 000 W kg-1, respectively.

  14. Porous titania surfaces on titanium with hierarchical macro- and mesoporosities for enhancing cell adhesion, proliferation and mineralization.

    PubMed

    Han, Guang; Müller, Werner E G; Wang, Xiaohong; Lilja, Louise; Shen, Zhijian

    2015-02-01

    Titanium received a macroporous titania surface layer by anodization, which contains open pores with average pore diameter around 5 μm. An additional mesoporous titania top layer following the contour of the macropores, of 100-200 nm thickness and with a pore diameter of 10nm, was formed by using the evaporation-induced self-assembly (EISA) method with titanium (IV) tetraethoxide as the precursor. A coherent laminar titania surface layer was thus obtained, creating a hierarchical macro- and mesoporous surface that was characterized by high-resolution electron microscopy. The interfacial bonding between the surface layers and the titanium matrix was characterized by the scratch test that confirmed a stable and strong bonding of titania surface layers on titanium. The wettability to water and the effects on the osteosarcoma cell line (SaOS-2) proliferation and mineralization of the formed titania surface layers were studied systematically by cell culture and scanning electron microscopy. The results proved that the porous titania surface with hierarchical macro- and mesoporosities was hydrophilic that significantly promoted cell attachment and spreading. A synergistic role of the hierarchical macro- and mesoporosities was revealed in terms of enhancing cell adhesion, proliferation and mineralization, compared with the titania surface with solo scale topography. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. The role of nano-particles in the field of thermal spray coating technology

    NASA Astrophysics Data System (ADS)

    Siegmann, Stephan; Leparoux, Marc; Rohr, Lukas

    2005-06-01

    Nano-particles play not only a key role in recent research fields, but also in the public discussions about health and safety in nanotechnology. Nevertheless, the worldwide activities in nano-particles research increased dramatically during the last 5 to 10 years. There are different potential routes for the future production of nano-particles at large scale. The main directions envisaged are mechanical milling, wet chemical reactions or gas phase processes. Each of the processes has its specific advantages and limitations. Mechanical milling and wet chemical reactions are typically time intensive and batch processes, whereas gas phase productions by flames or plasma can be carried out continuously. Materials of interest are mainly oxide ceramics, carbides, nitrides, and pure metals. Nano-ceramics are interesting candidates for coating technologies due to expected higher coating toughness, better thermal shock and wear resistance. Especially embedded nano-carbides and-nitrides offer homogenously distributed hard phases, which enhance coatings hardness. Thermal spraying, a nearly 100 years old and world wide established coating technology, gets new possibilities thanks to optimized, nano-sized and/or nano-structured powders. Latest coating system developments like high velocity flame spraying (HVOF), cold gas deposition or liquid suspension spraying in combination with new powder qualities may open new applications and markets. This article gives an overview on the latest activities in nano-particle research and production in special relation to thermal spray coating technology.

  16. High-density arrays of titania nanoparticles using monolayer micellar films of diblock copolymers as templates.

    PubMed

    Li, Xue; Lau, King Hang Aaron; Kim, Dong Ha; Knoll, Wolfgang

    2005-05-24

    Highly dense arrays of titania nanoparticles were fabricated using surface micellar films of poly(styrene-block-2-vinylpyridine) diblock copolymers (PS-b-P2VP) as reaction scaffolds. Titania could be introduced selectively within P2VP nanodomains in PS-b-P2VP films through the binary reaction between water molecules trapped in the P2VP domains and the TiCl(4) vapor precursors. Subsequent UV exposure or oxygen plasma treatment removed the organic matrix, leading to titania nanoparticle arrays on the substrate surface. The diameter of the titania domains and the interparticle distance were defined by the lateral scale present in the microphase-separated morphology of the initial PS-b-P2VP films. The typical diameter of titania nanoparticles obtained by oxygen plasma treatment was of the order of approximately 23 nm. Photoluminescence (PL) properties were investigated for films before and after plasma treatment. Both samples showed PL properties with major physical origin due to self-trapped excitons, indicating that the local environment of the titanium atoms is similar.

  17. Nonlinear optical properties and supercontinuum spectrum of titania-modified carbon quantum dots

    NASA Astrophysics Data System (ADS)

    Kulchin, Yu N.; Mayor, A. Yu; Proschenko, D. Yu; Postnova, I. V.; Shchipunov, Yu A.

    2016-04-01

    We have studied the nonlinear optical properties and supercontinuum spectrum of solutions of carbon quantum dots prepared by a hydrothermal process from chitin and then coated with titania. The titania coating has been shown to have an activating effect on the carbon quantum dots, enhancing supercontinuum generation in the blue-violet spectral region and enabling their nonlinear optical characteristics to be varied.

  18. F-T process using an iron on mixed zirconia-titania supported catalyst

    DOEpatents

    Dyer, Paul N.; Nordquist, Andrew F.; Pierantozzi, Ronald

    1987-01-01

    A Fischer-Tropsch catalyst comprising iron co-deposited with or deposited on particles comprising a mixture of zirconia and titania, preferably formed by co-precipitation of compounds convertible to zirconia and titania, such as zirconium and titanium alkoxide. The invention also comprises the method of making this catalyst and an improved Fischer-Tropsch reaction process in which the catalyst is utilized.

  19. Bioinspired hierarchical nanotubular titania immobilized with platinum nanoparticles for photocatalytic hydrogen production.

    PubMed

    Liu, Xiaoyan; Li, Jiao; Zhang, Yiming; Huang, Jianguo

    2015-05-11

    A bioinspired nanocomposite composed of platinum nanoparticles and nanotubular titania was fabricated in which the titania matter was templated by natural cellulose substance. The composite possesses three- dimensional hierarchical structures, and ultrafine metallic platinum particles with sizes of ca. 2 nm were immobilized uniformly on the surfaces of the titania nanotubes. Such a nanocomposite with 1.06 wt % of platinum content shows the optimal photocatalytic hydrogen production activity from water splitting of 16.44 mmol h(-1)  g(-1) , and excessive loading of platinum results in poorer photocatalytic performance. The structural integrity of the nanocomposite upon cyclic water-splitting processes results in its sufficient photocatalytic stability. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Equal channel angular pressing of powder processed Al6061/SiC nano metal matrix composites and study of its wear properties

    NASA Astrophysics Data System (ADS)

    Bongale, Arunkumar M.; Kumar, Satish

    2018-03-01

    Nano Metal Matrix Composites were fabricated by a novel approach by combining powder metallurgy and equal channel angular pressing (ECAP) using aluminium alloy 6061 (Al6061) as matrix phase and 2, 4 and 6 wt% of silicon carbide nanoparticles (SiCnp) as reinforcements. Alloying elements of Al6061 in their elemental form are blended together using high energy planetary ball mill and calculated wt% of SiCnp were mixed with it. Thus formed composite powder mixture is compacted in a uniaxial compaction die and then subjected to ECAP up to three passes. Density and porosity of samples were estimated using Archimedes’ principle. Pin on disc setup is used to evaluate the wear properties of the composites under different speed and loading conditions. Tests revealed that increase in wt% of SiCnp reduces the wear rate of the composites whereas increasing the load and speed increases wear rate of the composite samples. SEM micrographs of worn surfaces indicated different types of wear mechanism responsible for wear of the specimens under different testing conditions. Also, wt% of SiCnp and the number of passes through ECAP were found to increase the hardness value of the composite material.

  1. Rapid fabrication of titania nanofibers by electrospinning

    NASA Astrophysics Data System (ADS)

    Li, Dan; Xia, Younan

    2003-11-01

    This paper describes a simple and convenient procedure for fabricating polycrystalline titania nanofibers with controllable diameter and porous structures. By combining sol-gel technique and electrospinning, nanofibers made of poly(vinyl pyrrolidone) (PVP) and amorphous TiO2 were firstly obtained by electrospinning an ethanol solution containing both PVP and titanium tetraisopropoxide under appropriate high voltages. These nanofibers could be subsequently converted to anatase without changing their morphology via calcination in air at 500°C. The average diameter of these ceramic nanofibers could be controlled in the range from 20 to 200 nm by varying a number of parameters such as the voltage, the feeding rate of the precursor solution, the ratio between PVP and titanium tetraisopropoxide, and their concentrations in the alcohol solution. Titanium tetraisopropoxide could be transferred to titania nanofibers with ~100% yield by using this technique.

  2. Titania-coated manganite nanoparticles: Synthesis of the shell, characterization and MRI properties

    NASA Astrophysics Data System (ADS)

    Jirák, Zdeněk; Kuličková, Jarmila; Herynek, Vít; Maryško, Miroslav; Koktan, Jakub; Kaman, Ondřej

    2017-04-01

    Novel procedure for coating of oxide nanoparticles with titania, employing hydrolysis and polycondensation of titanium alkoxides under high-dilution conditions and cationic surfactants, is developed and applied to magnetic cores of perovskite manganite. Bare particles of the ferromagnetic La0.65Sr0.35MnO3 phase, possessing high magnetization, M10 kOe(4.5 K) = 63.5 emu g-1, and Curie temperature, TC = 355 K, are synthesized by sol-gel procedure and subsequently coated with titania. Further, a comparative silica-coated product is prepared. In order to analyse the morphology, colloidal stability, and surface properties of these two types of coated particles, a detailed study by means of transmission electron microscopy, dynamic light scattering, zeta-potential measurements, and IR spectroscopy is carried out. The experiments on the titania-coated sample reveal a continuous though porous character of the TiO2 shell, the nature of which is amorphous but can be transformed to anatase at higher temperatures. Finally, the relaxometric study at the magnetic field of 0.5 T, performed to quantity the transverse relaxivity and its temperature dependence, reveals important differences between the titania-coated and silica-coated nanoparticles.

  3. Immobilization in cement mortar of chromium removed from water using titania nanoparticles.

    PubMed

    Husnain, Ahmed; Qazi, Ishtiaq Ahmed; Khaliq, Wasim; Arshad, Muhammad

    2016-05-01

    Because of the high toxicity of chromium, particularly as Cr (VI), it is removed from industrial effluents before their discharge into water bodies by a variety of techniques, including adsorption. Ultimate disposal of the sludge or the adsorbate, however, is a serious problem. While titania, in nanoparticle form, serves as a very good adsorbent for chromium, as an additive, it also helps to increase the compressive strength of mortar and concrete. Combining these two properties of the material, titania nanoparticles were used to adsorb chromium and then added to mortar up to a concentration of 20% by weight. The compressive strength of the resulting mortar specimens that replaced 15% of cement with chromium laden titania showed an improved strength than that without titania, thus confirming that this material had positive effect on the mortar strength. Leachate tests using the Toxicity Characteristics Leaching Procedure (TCLP) confirmed that the mortar sample chromium leachate was well within the permissible limits. The proposed technique thus offers a safe and viable method for the ultimate disposal of toxic metal wastes, in general, and those laden waste chromium, in particular. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Synthesis, characterization and photocatalytic activity of porous manganese oxide doped titania for toluene decomposition.

    PubMed

    Jothiramalingam, R; Wang, M K

    2007-08-17

    The present study describes the photocatalytic degradation of toluene in gas phase on different porous manganese oxide doped titanium dioxide. As synthesized birnessite and cryptomelane type porous manganese oxide were doped with titania and tested for photocatalytic decomposition of toluene in gas phase. The effects of the inlet concentration of toluene, flow rate (retention time) were examined and the relative humidity was maintained constantly. Thermal and textural characterization of manganese oxide doped titania materials were characterized by X-ray diffraction (XRD), thermogravemetry (TG), BET and TEM-EDAX studies. The aim of the present study is to synthesize the porous manganese oxide doped titania and to study its photocatalytic activity for toluene degradation in gas phase. Cryptomelane doped titania catalyst prepared in water medium [K-OMS-2 (W)] is shown the good toluene degradation with lower catalysts loading compared to commercial bulk titania in annular type photo reactor. The higher photocatalytic activity due to various factors such as catalyst preparation method, experimental conditions, catalyst loading, surface area, etc. In the present study manganese oxide OMS doped titania materials prepared by both aqueous and non-aqueous medium, aqueous medium prepared catalyst shows the good efficiency due to the presence of OH bonded groups on the surface of catalyst. The linear forms of different kinetic equations were applied to the adsorption data and their goodness of fit was evaluated based on the R2 and standard error. The goodness to the linear fit was observed for Elovich model with high R2 (>or=0.9477) value.

  5. Titania may produce abiotic oxygen atmospheres on habitable exoplanets

    PubMed Central

    Narita, Norio; Enomoto, Takafumi; Masaoka, Shigeyuki; Kusakabe, Nobuhiko

    2015-01-01

    The search for habitable exoplanets in the Universe is actively ongoing in the field of astronomy. The biggest future milestone is to determine whether life exists on such habitable exoplanets. In that context, oxygen in the atmosphere has been considered strong evidence for the presence of photosynthetic organisms. In this paper, we show that a previously unconsidered photochemical mechanism by titanium (IV) oxide (titania) can produce abiotic oxygen from liquid water under near ultraviolet (NUV) lights on the surface of exoplanets. Titania works as a photocatalyst to dissociate liquid water in this process. This mechanism offers a different source of a possibility of abiotic oxygen in atmospheres of exoplanets from previously considered photodissociation of water vapor in upper atmospheres by extreme ultraviolet (XUV) light. Our order-of-magnitude estimation shows that possible amounts of oxygen produced by this abiotic mechanism can be comparable with or even more than that in the atmosphere of the current Earth, depending on the amount of active surface area for this mechanism. We conclude that titania may act as a potential source of false signs of life on habitable exoplanets. PMID:26354078

  6. Titania may produce abiotic oxygen atmospheres on habitable exoplanets.

    PubMed

    Narita, Norio; Enomoto, Takafumi; Masaoka, Shigeyuki; Kusakabe, Nobuhiko

    2015-09-10

    The search for habitable exoplanets in the Universe is actively ongoing in the field of astronomy. The biggest future milestone is to determine whether life exists on such habitable exoplanets. In that context, oxygen in the atmosphere has been considered strong evidence for the presence of photosynthetic organisms. In this paper, we show that a previously unconsidered photochemical mechanism by titanium (IV) oxide (titania) can produce abiotic oxygen from liquid water under near ultraviolet (NUV) lights on the surface of exoplanets. Titania works as a photocatalyst to dissociate liquid water in this process. This mechanism offers a different source of a possibility of abiotic oxygen in atmospheres of exoplanets from previously considered photodissociation of water vapor in upper atmospheres by extreme ultraviolet (XUV) light. Our order-of-magnitude estimation shows that possible amounts of oxygen produced by this abiotic mechanism can be comparable with or even more than that in the atmosphere of the current Earth, depending on the amount of active surface area for this mechanism. We conclude that titania may act as a potential source of false signs of life on habitable exoplanets.

  7. Effect of calcination temperature on the photocatalytic reduction and oxidation processes of hydrothermally synthesized titania nanotubes.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Viayan, B.; Dimitrijevic, N. M.; Rajh, T.

    Titania nanotubes having diameters 8 to 12 nm and lengths of 50-300 nm were prepared using a hydrothermal method. Further, the titania nanotubes were calcined over the temperature range 200-800 C in order to enhance their photocatalytic properties by altering their morphology. The calcined titania nanotubes were characterized by using X-ray diffraction and surface area analysis and their morphological features were studied by scanning and transmission electron microscopy. Nanotubes calcined at 400 C showed the maximum extent of photocatalyitc reduction of carbon dioxide to methane, whereas samples calcined at 600 C produced maximum photocatalytic oxidation of acetaldehyde. Electron paramagnetic resonancemore » (EPR) spectroscopy was used to interrogate the effects of nanotube structure on the charge separation and trapping as a function of calcination temperature. EPR results indicated that undercoordinated titania sites are associated with maximum CO{sub 2} reduction occurring in nanotubes calcined at 400 C. Despite the collapse of the nantube structure to form nanorods and the concomitant loss of surface area, the enhanced charge separation associated with increased crystallinity promoted high rates of oxidation of acetaldehyde in titania materials calcined at 600 C. These results illustrate that calcination temperature allows us to tune the morphological and surface features of the titania nanostructures for particular photocatalytic reactions.« less

  8. Titania nano-coated quartz wool for the photocatalytic mineralisation of emerging organic contaminants.

    PubMed

    Saracino, M; Pretali, L; Capobianco, M L; Emmi, S S; Navacchia, M L; Bezzi, F; Mingazzini, C; Burresi, E; Zanelli, A

    2018-01-01

    Many emerging contaminants pass through conventional wastewater treatment plants, contaminating surface and drinking water. The implementation of advanced oxidation processes in existing plants for emerging contaminant remediation is one of the challenges for the enhancement of water quality in the industrialised countries. This paper reports on the production of a TiO 2 nano-layer on quartz wool in a relevant amount, its characterisation by X-ray diffraction and scanning electron microscopy, and its use as a photocatalyst under ultraviolet radiation for the simultaneous mineralisation of five emerging organic contaminants (benzophenone-3, benzophenone-4, carbamazepine, diclofenac, and triton X-100) dissolved in deionised water and tap water. This treatment was compared with direct ultraviolet photolysis and with photocatalytic degradation on commercial TiO 2 micropearls. The disappearance of every pollutant was measured by high performance liquid chromatography and mineralisation was assessed by the determination of total organic carbon. After 4 hours of treatment with the TiO 2 nano-coated quartz wool, the mineralisation exceeds 90% in deionised water and is about 70% in tap water. This catalyst was reused for seven cycles without significant efficiency loss.

  9. Hafnia-rich mixed oxide ceramics of the system HfO2-ZrO2-TiO2 for heaters and heat exchangers in electrothermal thrusters: The effects of titania on selected electrical and mechanical properties of Hafnia-rich mixed oxides in the system Hafnia-Zirconia-Titania, volume 1

    NASA Technical Reports Server (NTRS)

    Staszak, Paul Russell; Wirtz, G. P.; Berg, M.; Brown, S. D.

    1988-01-01

    A study of the effects of titania on selected properties of hafnia-rich mixed oxides in the system hafnia-zirconia-titania (HZT) was made in the region 5 to 20 mol percent titania. The studied properties included electrical conductivity, thermal expansion, and fracture strength and toughness. The effects of titania on the properties were studied for the reduced state as well as the oxidized state of the sintered mixed oxides. X-ray analysis showed that the materials were not always single phase. The oxidized compositions went from being monoclinic solid solutions at low titania additions to having three phases (two monoclinic and a titanate phase) at high additions of titania. The reduced compositions showed an increasing cubic phase presence mixed with the monoclinic phase as titania was added. The electrical conductivity increased with temperature at approximately 0.1 mhos/cm at 1700 C for all compositions. The thermal expansion coefficient decreased with increasing titania as did the monoclinic to tetragonal transformation temperature. The fracture strength of the oxidized bars tended to decrease with the addition of titania owing to the presence of the second phase titania. The fracture strength of the reduced bars exhibited a minimum corresponding to a two-phase region of monoclinic and cubic phases. When the second phases were suppressed, the titania tended to increase the fracture strength slightly in both the oxidized and reduced states. The fracture toughness followed similar trends.

  10. Chemical Dynamics of nano-Aluminum and Iodine Based Oxidizers

    NASA Astrophysics Data System (ADS)

    Little, Brian; Ridge, Claron; Overdeep, Kyle; Slizewski, Dylan; Lindsay, Michael

    2017-06-01

    As observed in previous studies of nanoenergetic powder composites, micro/nano-structural features such as particle morphology and/or reactant spatial distance are expected to strongly influence properties that govern the combustion behavior of energetic materials (EM). In this study, highly reactive composites containing crystalline iodine (V) oxide or iodate salts with nano-sized aluminum (nAl) were blended by two different processing techniques and then collected as a powder for characterization. Physiochemical techniques such as thermal gravimetric analysis, calorimetry, X-ray diffraction, electron microscopy, high speed photography, pressure profile analysis, temperature programmed reactions, and spectroscopy were employed to characterize these EM with emphasis on correlating the chemical reactivity with inherent structural features and variations in stoichiometry. This work is a continuation of efforts to probe the chemical dynamics of nAl-iodine based composites.

  11. Effect of alkali ions (Na+, K+, Cs+) on reaction mechanism of CZTS nano-particles synthesis

    NASA Astrophysics Data System (ADS)

    Kumar, Suresh; Altosaar, Mare; Grossberg, Maarja; Mikli, Valdek

    2018-04-01

    The control of morphology, elemental composition and phase composition of Cu2ZnSnS4 (CZTS) nano-crystals depends on the control of complex formation and surface stabilization of nano-particles in solution-based synthesis in oleylamine. At temperatures ≥280 °C, the control of nano-crystal's morphology and homogenous growth is difficult because of fast poly-nuclear growth occurring at higher temperatures. In the present work the effect of oleylamine complex formation with different alkali ions (Na+, K+ and Cs+) on nano-crystals growth at synthesis temperature of 280 °C was studied. It was found that nano-powders synthesized in the presence of Na+ and K+ ions showed the formation of crystals of different sizes - small nano-particles (18 nm-30 nm), large aggregated crystals (few nm to 1 μm) and large single crystals (1 μm - 4 μm). The presence of Cs+ ions in the nano-powder synthesis in oleylamine-metal precursor-CsOH solution promoted growth of nano-crystals of homogenous size. It is proposed that the formed oleylamine-Cs complexes a) enhance the formation and stabilization of oleylamine-metal (Cu, Zn and Sn) complexes before the injection of sulphur precursor into the oleylamine-metal precursor solution and b) after addition of sulphur stabilize the fast nucleated nano-particles and promote diffusion limited growth.

  12. Exchange bias effect and glassy-like behavior of EuCrO{sub 3} and CeCrO{sub 3} nano-powders

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Taheri, M., E-mail: maryam.taheri@brocku.ca; Razavi, F. S.; Kremer, R. K.

    2015-09-28

    The magnetic properties of nano-sized EuCrO{sub 3} and CeCrO{sub 3} powders, synthesized by a solution combustion method, were investigated using DC/AC magnetization measurements. An exchange bias effect, magnetization irreversibility and AC susceptibility dispersion in these samples provided evidence for the presence of the spin disorder magnetic phase. The exchange bias phenomenon, which is assigned to the exchange coupling between the glassy-like shell and canted antiferromagnetic core, showed the opposite sign in EuCrO{sub 3} and CeCrO{sub 3} at low temperatures, suggesting different exchange interactions at the interfaces in these compounds. We also observed a sign reversal of exchange bias in CeCrO{submore » 3} at different temperatures.« less

  13. Hydrothermal synthesis and characterization of hydroxyapatite and fluorhydroxyapatite nano-size powders.

    PubMed

    Montazeri, Leila; Javadpour, Jafar; Shokrgozar, Mohammad Ali; Bonakdar, Shahin; Javadian, Sayfoddin

    2010-08-01

    Pure hydroxyapatite (HAp) and fluoride-containing apatite powders (FHAp) were synthesized using a hydrothermal method. The powders were assessed by x-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscope (SEM) and F-selective electrode. X-ray diffraction results revealed the formation of single phase apatite structure for all the compositions synthesized in this work. However, the addition of a fluoride ion led to a systematic shift in the (3 0 0) peak of the XRD pattern as well as modifications in the FTIR spectra. It was found that the efficiency of fluoride ion incorporation decreased with the increase in the fluoride ion content. Fluorine incorporation efficiency was around 60% for most of the FHAp samples prepared in the current study. Smaller and less agglomerated particles were obtained by fluorine substitution. The bioactivity of the powder samples with different fluoride contents was compared by performing cell proliferation, alkaline phosphatase (ALP) and Alizarin red staining assays. Human osteoblast cells were used to assess the cellular responses to the powder samples in this study. Results demonstrated a strong dependence of different cell activities on the level of fluoridation.

  14. Preparation of LuAG Powders with Single Phase and Good Dispersion for Transparent Ceramics Using Co-Precipitation Method

    PubMed Central

    Pan, Liangjie; Jiang, Benxue; Fan, Jintai; Yang, Qiuhong; Zhou, Chunlin; Zhang, Pande; Mao, Xiaojian; Zhang, Long

    2015-01-01

    The synthesis of pure and well dispersed lutetium aluminum garnet (LuAG) powder is crucial and important for the preparation of LuAG transparent ceramics. In this paper, high purity and well dispersed LuAG powders have been synthesized via co-precipitation method with lutetium nitrate and aluminum nitrate as raw materials. Ammonium hydrogen carbonate (AHC) was used as the precipitant. The influence of aging time, pH value, and dripping speed on the prepared LuAG powders were investigated. It showed that long aging duration (>15 h) with high terminal pH value (>7.80) resulted in segregation of rhombus Lu precipitate and Al precipitate. By decreasing the initial pH value or accelerating the dripping speed, rhombus Lu precipitate was eliminated and pure LuAG nano powders were synthesized. High quality LuAG transparent ceramics with transmission >75% at 1064 nm were fabricated using these well dispersed nano LuAG powders. PMID:28793510

  15. Preparation of LuAG Powders with Single Phase and Good Dispersion for Transparent Ceramics Using Co-Precipitation Method.

    PubMed

    Pan, Liangjie; Jiang, Benxue; Fan, Jintai; Yang, Qiuhong; Zhou, Chunlin; Zhang, Pande; Mao, Xiaojian; Zhang, Long

    2015-08-19

    The synthesis of pure and well dispersed lutetium aluminum garnet (LuAG) powder is crucial and important for the preparation of LuAG transparent ceramics. In this paper, high purity and well dispersed LuAG powders have been synthesized via co-precipitation method with lutetium nitrate and aluminum nitrate as raw materials. Ammonium hydrogen carbonate (AHC) was used as the precipitant. The influence of aging time, pH value, and dripping speed on the prepared LuAG powders were investigated. It showed that long aging duration (>15 h) with high terminal pH value (>7.80) resulted in segregation of rhombus Lu precipitate and Al precipitate. By decreasing the initial pH value or accelerating the dripping speed, rhombus Lu precipitate was eliminated and pure LuAG nano powders were synthesized. High quality LuAG transparent ceramics with transmission >75% at 1064 nm were fabricated using these well dispersed nano LuAG powders.

  16. Comparative study of phase transition and textural changes upon calcination of two commercial titania samples: A pure anatase and a mixed anatase-rutile

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kordouli, Eleana; Dracopoulos, Vassileios; Vaimakis, Tiverios

    2015-12-15

    The effect of calcination temperature and time on structural and textural changes of two commercial TiO{sub 2} samples (pure anatase and a mixture of anatase and rutile) has been investigated using N{sub 2} physisorption, ex-situ and in-situ X-ray powder diffraction, differential scanning calorimetry and UV–vis diffuse reflectance spectroscopy. The increase of the calcination temperature (up to 700 °C) and time (up to 8 h) causes only textural changes in the pure anatase, whereas a transformation of the anatase to rutile takes place, in addition, in the mixed titania (containing anatase and rutile). The textural changes observed in pure anatase samplemore » were attributed to solid state diffusion leading to an increase in the size of anatase nanocrystals, through sintering. Thus, the mean pore diameter shifts to higher values and the pore volume and specific surface area decrease. The successful application of the Johnson–Mehl–Avrami–Kolmogorov model in the kinetic data concerning the pure anatase indicates a mass transfer control of sintering process. Similar textural changes were also observed upon calcination of the sample containing anatase and rutile. In this case not only sintering but the anatase to rutile transformation contributes also to the textural changes. Kinetic analysis showed that the rutile nanocrystals in the mixed titania served as seed for by-passing the high energy barrier nucleation step allowing/facilitating thus the anatase to rutile transformation. A fine control of the anatase to rutile ratio and thus of energy-gap and the population of hetero-junctions may be obtained by adjusting the calcination temperature and time. - Graphical Abstract: Dependence of anatase content of P25 on the calcination temperature (600 °C (■), 650 °C (●), 700 °C (▲)) and time. - Highlights: • Increase of calcination temperature up to 800 °C and time up to 8 h causes only textural changes in pure anatase • Progressive transformation of

  17. Hierarchical macro-mesoporous structures in the system TiO{sub 2}-Al{sub 2}O{sub 3}, obtained by hydrothermal synthesis using Tween-20 as a directing agent

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Garcia-Benjume, M.L.; Espitia-Cabrera, M.I.; Contreras-Garcia, M.E., E-mail: eucontre@zeus.umich.mx

    2009-12-15

    Macro-mesoporous powders of titania, alumina, and mixed titania-20%alumina systems were obtained by hydrothermal synthesis employing surfactant Tween-20 as structural directing agent in order to promote the textural properties of titania. The effect of the alumina in the titania phase and on textural properties was analyzed. The obtained powders presented a macroporous channel structure that was characterized by X-ray diffractometry, scanning and transmission electron microscopy, N{sub 2} adsorption-desorption analysis, pore size distribution, Fourier transform infrared spectrometry, and thermogravimetric analysis. It was found that alumina content retarded the anatase phase crystallization and increased the Brunauer-Emmet-Teller surface area from 136 to 210 m{supmore » 2}/g. The powders calcined at 400 deg. C are thermally stable and possess an interconnected macro-mesoporous hierarchical structure; the results indicate that this synthesis can be employed to prepare mixed titania-alumina with good textural properties.« less

  18. Mechanical Behavior of Polymer Nano Bio Composite for Orthopedic Implants

    NASA Astrophysics Data System (ADS)

    Marimuthu, K., Dr.; Rajan, Sankar

    2018-04-01

    The bio-based polymer composites have been the focus of many scientific and research projects, as well as many commercial programs. In recent years, scientists and engineers have been working together to use the inherent strength and performance of the new class of bio-based composites which is compactable with human body and can act as a substitute for living cells. In this stage the polymer composites also stepped into human bone implants as a replacement for metallic implants which was problems like corrosion resistance and high cost. The polymer composite have the advantage that it can be molded to the required shape, the polymers have high corrosion resistance, less weight and low cost. The aim of this research is to develop and analyze the suitable bio compactable polymer composite for human implants. The nano particles reinforced polymer composites provides good mechanical properties and shows good tribological properties especially in the total hip and knee replacements. The graphene oxide powders are bio compactable and acts as anti biotic. GO nano powder where reinforced into High-density polyethylene in various weight percentage of 0.5% to 2%. The performance of GO nano powder shows better tribological properties. The material produced does not cause any pollution to the environment and at the same time it can be bio compactable and sustainable. The product will act environmentally friendly.

  19. [Spectral studies on nano-sized titania photocatalysts prepared by different drying methods].

    PubMed

    Ye, Zhao; Zhang, Han-hui; Pan, Hai-bo; Pan, Hong-qing

    2002-12-01

    Nano-sized TiO2 photocatalysts were prepared by drying the ethanol gel of titanium tetrabutoxide through natural state, supercritical ethanol, supercritical carbon dioxide drying methods and characterized by XRD, FTIR spectroscopy, FT-Raman spectroscopy and fluorescent spectroscopy, respectively. We regard degradation of rhodamine B by photocatalyst as a model reaction, and compare photocatalytic activities of samples obtained. The experimental results show that different drying methods have strong effect on crystal structure, energy band structure, optical adsorption property, surface quality and photocatalytic activity, TiO2 photocatalyst prepared by supercritical carbon dioxide drying method has superior photocatalytic activity.

  20. Long vertically aligned titania nanotubes on transparent conducting oxide for highly efficient solar cells.

    PubMed

    Varghese, Oomman K; Paulose, Maggie; Grimes, Craig A

    2009-09-01

    Dye-sensitized solar cells consist of a random network of titania nanoparticles that serve both as a high-surface-area support for dye molecules and as an electron-transporting medium. Despite achieving high power conversion efficiencies, their performance is limited by electron trapping in the nanoparticle film. Electron diffusion lengths can be increased by transporting charge through highly ordered nanostructures such as titania nanotube arrays. Although titania nanotube array films have been shown to enhance the efficiencies of both charge collection and light harvesting, it has not been possible to grow them on transparent conducting oxide glass with the lengths needed for high-efficiency device applications (tens of micrometres). Here, we report the fabrication of transparent titania nanotube array films on transparent conducting oxide glass with lengths between 0.3 and 33.0 microm using a novel electrochemistry approach. Dye-sensitized solar cells containing these arrays yielded a power conversion efficiency of 6.9%. The incident photon-to-current conversion efficiency ranged from 70 to 80% for wavelengths between 450 and 650 nm.

  1. Design of titania nanotube structures by focused laser beam direct writing

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Enachi, Mihai; Stevens-Kalceff, Marion A.; Sarua, Andrei

    In this work, we report on electrochemical fabrication of titania films consisting of nanotubes (NTs) and their treatment by focused laser beam. The results of sample characterization by optical and scanning electron microscopy, cathodoluminescence imaging, and Raman scattering scanning spectroscopy are compared to those inherent to specimens subjected to thermal treatment in a furnace. The obtained data demonstrate possibilities for controlling crystallographic structure of TiO{sub 2} NTs by focused laser beam direct writing. These findings open new prospects for the design and fabrication of spatial architectures based on titania nanotubes.

  2. XPS and biocompatibility studies of titania film on anodized NiTi shape memory alloy.

    PubMed

    Chu, C L; Wang, R M; Hu, T; Yin, L H; Pu, Y P; Lin, P H; Dong, Y S; Guo, C; Chung, C Y; Yeung, K W K; Chu, Paul K

    2009-01-01

    A dense titania film is fabricated in situ on NiTi shape memory alloy (SMA) by anodic oxidation in a Na(2)SO(4) electrolyte. The microstructure of the titania film and its influence on the biocompatibility of NiTi SMA are investigated by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma mass spectrometry (ICPMS), hemolysis analysis, and platelet adhesion test. The results indicate that the titania film has a Ni-free zone near the surface and can effectively block the release of harmful Ni ions from the NiTi substrate in simulated body fluids. Moreover, the wettability, hemolysis resistance, and thromboresistance of the NiTi sample are improved by this anodic oxidation method.

  3. Atomically dispersed Au-(OH)x species bound on titania catalyze the low-temperature water-gas shift reaction.

    PubMed

    Yang, Ming; Allard, Lawrence F; Flytzani-Stephanopoulos, Maria

    2013-03-13

    We report a new method for stabilizing appreciable loadings (~1 wt %) of isolated gold atoms on titania and show that these catalyze the low-temperature water-gas shift reaction. The method combines a typical gold deposition/precipitation method with UV irradiation of the titania support suspended in ethanol. Dissociation of H2O on the thus-created Au-O-TiO(x) sites is facile. At higher gold loadings, nanoparticles are formed, but they were shown to add no further activity to the atomically bound gold on titania. Removal of this "excess" gold by sodium cyanide leaching leaves the activity intact and the atomically dispersed gold still bound on titania. The new materials may catalyze a number of other reactions that require oxidized active metal sites.

  4. Dynamic Diffraction Studies on the Crystallization, Phase Transformation, and Activation Energies in Anodized Titania Nanotubes.

    PubMed

    Albetran, Hani; Vega, Victor; Prida, Victor M; Low, It-Meng

    2018-02-23

    The influence of calcination time on the phase transformation and crystallization kinetics of anodized titania nanotube arrays was studied using in-situ isothermal and non-isothermal synchrotron radiation diffraction from room temperature to 900 °C. Anatase first crystallized at 400 °C, while rutile crystallized at 550 °C. Isothermal heating of the anodized titania nanotubes by an increase in the calcination time at 400, 450, 500, 550, 600, and 650 °C resulted in a slight reduction in anatase abundance, but an increase in the abundance of rutile because of an anatase-to-rutile transformation. The Avrami equation was used to model the titania crystallization mechanism and the Arrhenius equation was used to estimate the activation energies of the titania phase transformation. Activation energies of 22 (10) kJ/mol for the titanium-to-anatase transformation, and 207 (17) kJ/mol for the anatase-to-rutile transformation were estimated.

  5. Dynamic Diffraction Studies on the Crystallization, Phase Transformation, and Activation Energies in Anodized Titania Nanotubes

    PubMed Central

    Albetran, Hani; Vega, Victor

    2018-01-01

    The influence of calcination time on the phase transformation and crystallization kinetics of anodized titania nanotube arrays was studied using in-situ isothermal and non-isothermal synchrotron radiation diffraction from room temperature to 900 °C. Anatase first crystallized at 400 °C, while rutile crystallized at 550 °C. Isothermal heating of the anodized titania nanotubes by an increase in the calcination time at 400, 450, 500, 550, 600, and 650 °C resulted in a slight reduction in anatase abundance, but an increase in the abundance of rutile because of an anatase-to-rutile transformation. The Avrami equation was used to model the titania crystallization mechanism and the Arrhenius equation was used to estimate the activation energies of the titania phase transformation. Activation energies of 22 (10) kJ/mol for the titanium-to-anatase transformation, and 207 (17) kJ/mol for the anatase-to-rutile transformation were estimated. PMID:29473854

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Huang, Haiqing; Liu, Xiaoyan; Huang, Jianguo, E-mail: jghuang@zju.edu.cn

    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 andmore » 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.« less

  7. Fabrication and structural characterization of highly ordered titania nanotube arrays

    NASA Astrophysics Data System (ADS)

    Shi, Hongtao; Ordonez, Rosita

    Titanium (Ti) dioxide nanotubes have drawn much attention in the past decade due to the fact that titania is an extremely versatile material with a variety of technological applications. Anodizing Ti in different electrolytes has proved to be quite successful so far in creating the nanotubes, however, their degree of order is still not nearly as good as nanoporous anodic alumina. In this work, we first deposit a thin layer of aluminum (Al) onto electropolished Ti substrates, using thermal evaporation. Such an Al layer is then anodized in 0.3 M oxalic acid, forming an ordered nanoporous alumina mask on top of Ti. Afterwards, the anodization of Ti is accomplished at 20 V in solutions containing 1 M NaH2PO4 and 0.5% HF or H2SO4, which results in the creation of ordered titania nanotube arrays. The inner pore diameter of the nanotubes can be tuned from ~50 nm to ~75 nm, depending on the anodization voltage applied to Al or Ti. X-ray diffractometry shows the as-grown titania nanotubes are amorphous. Samples annealed at different temperatures in ambient atmosphere will be also reported.

  8. Nanophase hydroxyapatite coatings for dental and orthopedic applications

    NASA Astrophysics Data System (ADS)

    Sato, Michiko

    In order to improve dental and orthopedic implant performance, the objective of this study was to synthesize nanocrystalline hydroxyapatite (HA) powders to coat metals (specifically, titanium and tantalum). Precipitated HA powders were either sintered in order to produce UltraCaP HA (or microcrystalline size HA) or were treated hydrothermally to produce nanocrystalline HA. Some of the UltraCaP and nanocrystalline HA powders were doped with yttrium (Y) since previous in vitro studies demonstrated that Y-doped HA in bulk improved osteoblast (or bone-forming cell) function over undoped HA. The nanocrystalline HA powders were also mixed with nanophase titania powders because previous studies demonstrated that titania/HA composite coatings increased coating adhesive strength and HA nucleation. These powders were then deposited onto titanium by a novel room-temperature process, called IonTiteT(TM). The results demonstrated that the chemical properties and crystallite size of the original HA powders were maintained in the coatings. More importantly, in vitro studies showed increased osteoblast (bone-forming cell) adhesion on the single phase nanocrystalline HA and nano-titania/HA coatings compared to traditionally used plasma-sprayed HA coatings and uncoated metals. Results further demonstrated greater amounts of calcium deposition by osteoblasts cultured on nanocrystalline HA coatings compared to UltraCaP coatings and conventionally used plasma-sprayed HA coatings. To elucidate mechanisms that influenced osteoblast functions on the HA coatings, the amount of proteins (fibronectin and vitronectin) onto the HA powders and the adsorbed fibronectin conformation were investigated. Exposure of cell integrin binding domains (in fibronectin III10 segments) was greater in fibronectin adsorbed onto 1.2 mole% Y-doped UltraCaP HA coatings compared to nanocrystalline HA coatings tested. However, 1.2 mole% Y-doped UltraCaP HA coatings did not increase mineralization by osteoblasts

  9. Macroscale and Nanoscale Morphology Evolution during in Situ Spray Coating of Titania Films for Perovskite Solar Cells.

    PubMed

    Su, Bo; Caller-Guzman, Herbert A; Körstgens, Volker; Rui, Yichuan; Yao, Yuan; Saxena, Nitin; Santoro, Gonzalo; Roth, Stephan V; Müller-Buschbaum, Peter

    2017-12-20

    Mesoporous titania is a cheap and widely used material for photovoltaic applications. To enable a large-scale fabrication and a controllable pore size, we combined a block copolymer-assisted sol-gel route with spray coating to fabricate titania films, in which the block copolymer polystyrene-block-poly(ethylene oxide) (PS-b-PEO) is used as a structure-directing template. Both the macroscale and nanoscale are studied. The kinetics and thermodynamics of the spray deposition processes are simulated on a macroscale, which shows a good agreement with the large-scale morphology of the spray-coated films obtained in practice. On the nanoscale, the structure evolution of the titania films is probed with in situ grazing incidence small-angle X-ray scattering (GISAXS) during the spray process. The changes of the PS domain size depend not only on micellization but also on solvent evaporation during the spray coating. Perovskite (CH 3 NH 3 PbI 3 ) solar cells (PSCs) based on sprayed titania film are fabricated, which showcases the suitability of spray-deposited titania films for PSCs.

  10. Micro-structure and Mechanical Properties of Nano-TiC Reinforced Inconel 625 Deposited using LAAM

    NASA Astrophysics Data System (ADS)

    Bi, G.; Sun, C. N.; Nai, M. L.; Wei, J.

    In this paper, deposition of Ni-base Inconel 625 mixed with nano-TiC powders using laser aided additive manufacturing (LAAM) was studied. Micro-structure and mechanical properties were intensively investigated. The results showed that nano-size TiC distributed uniformly throughout the Ni- matrix. Inconel 625 can be reinforced by the strengthened grain boundaries with nano-size TiC. Improved micro-hardness and tensile properties were observed.

  11. Ultraviolet Laser Lithography of Titania Photonic Crystals for Terahertz-Wave Modulation.

    PubMed

    Kirihara, Soshu; Nonaka, Koki; Kisanuki, Shoichiro; Nozaki, Hirotoshi; Sakaguchi, Keito

    2018-05-18

    Three-dimensional (3D) microphotonic crystals with a diamond structure composed of titania microlattices were fabricated using ultraviolet laser lithography, and the bandgap properties in the terahertz (THz) electromagnetic-wave frequency region were investigated. An acrylic resin paste with titania fine particle dispersions was used as the raw material for additive manufacturing. By scanning a spread paste surface with an ultraviolet laser beam, two-dimensional solid patterns were dewaxed and sintered. Subsequently, 3D structures with a relative density of 97% were created via layer lamination and joining. A titania diamond lattice with a lattice constant density of 240 µm was obtained. The properties of the electromagnetic wave were measured using a THz time-domain spectrometer. In the transmission spectra for the Γ-X direction, a forbidden band was observed from 0.26 THz to 0.44 THz. The frequency range of the bandgap agreed well with calculated results obtained using the plane⁻wave expansion method. Additionally, results of a simulation via transmission-line modeling indicated that a localized mode can be obtained by introducing a plane defect between twinned diamond lattice structures.

  12. First principles study of vibrational dynamics of ceria-titania hybrid clusters

    NASA Astrophysics Data System (ADS)

    Majid, Abdul; Bibi, Maryam

    2017-04-01

    Density functional theory based calculations were performed to study vibrational properties of ceria, titania, and ceria-titania hybrid clusters. The findings revealed the dominance of vibrations related to oxygen when compared to those of metallic atoms in the clusters. In case of hybrid cluster, the softening of normal modes related to exterior oxygen atoms in ceria and softening/hardening of high/low frequency modes related to titania dimmers are observed. The results calculated for monomers conform to symmetry predictions according to which three IR and three Raman active modes were detected for TiO2, whereas two IR active and one Raman active modes were observed for CeO2. The comparative analysis indicates that the hybrid cluster CeTiO4 contains simultaneous vibrational fingerprints of the component dimmers. The symmetry, nature of vibrations, IR and Raman activity, intensities, and atomic involvement in different modes of the clusters are described in detail. The study points to engineering of CeTiO4 to tailor its properties for technological visible region applications in photocatalytic and electrochemical devices.

  13. Gas sensing performance of nano zinc oxide sensors

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sharma, Shiva, E-mail: shivasharmaau@gmail.com; Chauhan, Pratima, E-mail: mangu167@yahoo.co.in

    We report nano Zinc Oxide (ZnO) synthesized by sol-gel method possessing the crystallite size which varies from 25.17 nm to 47.27 nm. The Scanning electron microscope (SEM) image confirms the uniform distribution of nanograins with high porosity. The Energy dispersion X-ray (EDAX) spectrum gives the atomic composition of Zn and O in ZnO powders and confirms the formation of nano ZnO particles. These factors reveals that Nano ZnO based gas sensors are highly sensitive to Ammonia gas (NH{sub 3}) at room temperature, indicating the maximum response 86.8% at 800 ppm with fast response time and recovery time of 36 sec and 23 secmore » respectively.« less

  14. Iron on mixed zirconia-titania substrate Fischer-Tropsch catalyst and method of making same

    DOEpatents

    Dyer, Paul N.; Nordquist, Andrew F.; Pierantozzi, Ronald

    1986-01-01

    A Fischer-Tropsch catalyst comprising iron co-deposited with or deposited on particles comprising a mixture of zirconia and titania, preferably formed by co-precipitation of compounds convertible to zirconia and titania, such as zirconium and titanium alkoxide. The invention also comprises the method of making this catalyst and an improved Fischer-Tropsch reaction process in which the catalyst is utilized.

  15. Synthesis and structural characterization of nano-hydroxyapatite biomaterials prepared by microwave processing

    NASA Astrophysics Data System (ADS)

    Ramli, Rosmamuhamadani; Arawi, Ainaa Zafirah Omar; Talari, Mahesh Kumar; Mahat, Mohd Muzamir; Jais, Umi Sarah

    2012-07-01

    Synthetic hydroxyapatite, (HA, Ca10(PO4)6(OH)2), is an attractive and widely utilized bio-ceramic material for orthopedic and dental implants because of its close resemblance of native tooth and bone crystal structure. Synthetic HA exhibits excellent osteoconductive properties. Osteoconductivity means the ability to provide the appropriate scaffold or template for bone formation. Calcium phosphate biomaterials [(HA), tri-calcium phosphate (TCP) and biphasic calcium phosphate (HA/TCP)] with appropriate three-dimensional geometry are able to bind and concentrate endogenous bone morphogenetic proteins in circulation, and may become osteoinductive and can be effective carriers of bone cell seeds. This HA can be used in bio-implants as well as drug delivery application due to the unique properties of HA. Biomaterials synthesized from the natural species like mussel shells have additional benefits such as high purity, less expensive and high bio compatibility. In this project, HA-nanoparticles of different crystallite size were prepared by microwave synthesis of precursors. High purity CaO was extracted from the natural mussel shells for the synthesis of nano HA. Dried nano HA powders were analyzed using X-Ray Diffraction (XRD) technique for the determination of crystal structure and impurity content. Scanning Electron Microscopic (SEM) investigation was employed for the morphological investigation of nano HA powders. From the results obtained, it was concluded that by altering the irradiation time, nano HA powders of different crystallite sizes and morphologies could be produced. Crystallite sizes calculated from the XRD patterns are found to be in the range of 10-55 nm depending on the irradiation time.

  16. Nanocrystalline Anatase Titania Supported Vanadia Catalysts: Facet-dependent Structure of Vanadia

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Li, Wei-Zhen; Gao, Feng; Li, Yan

    2015-07-09

    Titania supported vanadia, a classic heterogeneous catalyst for redox reactions, typically has nonhomogeneous vanadia species on various titania facets, making it challenging not only to determine and quantify each species but also to decouple their catalytic contributions. We prepared truncated tetragonal bipyramidal (TiO2-TTB) and rod-like (TiO2-Rod) anatase titania with only {101} and {001} facets at ratios of about 80:20 and 93:7, respectively, and used them as supports of sub-monolayer vanadia. The structure and redox properties of supported vanadia were determined by XRD, TEM, XPS, EPR, Raman, FTIR and TPR, etc. It was found that vanadia preferentially occupy TiO2 {001} facetsmore » and form isolated O=V4+(O-Ti)2 species, and with further increase in vanadia surface coverage, isolated O=V5+(O-Ti)3 and oligomerized O=V5+(O-M)3 (M = Ti or V) species form on TiO2 {101} facets. The discovery on support facet-dependent structure of vanadia on anatase titania is expected to enable the elucidation of structure-function correlations on high surface area TiO2 supported vanadia catalysts. This work was supported by U. S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Biosciences and Geosciences. The research was performed in the Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by the DOE Office of Biological and Environmental Research, and located at Pacific Northwest National Laboratory (PNNL). PNNL is operated for DOE by Battelle.« less

  17. Antibacterial activity and interaction mechanism of electrospun zinc-doped titania nanofibers.

    PubMed

    Amna, Touseef; Hassan, M Shamshi; Barakat, Nasser A M; Pandeya, Dipendra Raj; Hong, Seong Tshool; Khil, Myung-Seob; Kim, Hak Yong

    2012-01-01

    In this study, a biological evaluation of the antimicrobial activity of Zn-doped titania nanofibers was carried out using Escherichia coli ATCC 52922 (Gram negative) and Staphylococcus aureus ATCC 29231 (Gram positive) as model organisms. The utilized Zn-doped titania nanofibers were prepared by the electrospinning of a sol-gel composed of zinc nitrate, titanium isopropoxide, and polyvinyl acetate; the obtained electrospun nanofibers were vacuum dried at 80°C and then calcined at 600°C. The physicochemical properties of the synthesized nanofibers were determined by X-ray diffraction pattern, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, electron probe microanalysis, thermogravimetry, and transmission electron microscopy (TEM). The antibacterial activity and the acting mechanism of Zn-doped titania nanofibers against bacteria were investigated by calculation of minimum inhibitory concentration and analyzing the morphology of the bacterial cells following the treatment with nanofibers solution. Our investigations reveal that the lowest concentration of Zn-doped titania nanofibers solution inhibiting the growth of S. aureus ATCC 29231 and E. coli ATCC 52922 strains is found to be 0.4 and 1.6 μg/ml, respectively. Furthermore, Bio-TEM analysis demonstrated that the exposure of the selected microbial strains to the nanofibers led to disruption of the cell membranes and leakage of the cytoplasm. In conclusion, the combined results suggested doping promotes antimicrobial effect; synthesized nanofibers possess a very large surface-to-volume ratio and may damage the structure of the bacterial cell membrane, as well as depress the activity of the membranous enzymes which cause bacteria to die in due course.

  18. Electrically conductive ceramic powders

    NASA Astrophysics Data System (ADS)

    Lu, Yanxia

    1999-11-01

    Electrically conductive ceramic powders were investigated in this project. There are three ways to produce those materials. The first is doping alkali metal into the titanium dioxides in an inert or reducing atmosphere. The second is reducing un-doped titanium dioxide, forming a non-stoichiometric composition in a hydrogen atmosphere. The third is to coat a conductive layer, reduced titanium dioxide, on an insulating core such as alumina. Highly conductive powders have been produced by all these processes. The conductivity of powder compacts ranged between 10-2 and 10° S/cm. A novel doping process was developed. All samples were doped by a solid-vapor reaction instead of a solid state reaction. Titanium dioxide was doped with alkali metals such as Na or Li in this study. The alkali metal atom contributes an electron to the host material (TiO2), which then creates Ti 3+ ion. The conductivity was enhanced by creating the donor level due to the presence of these Ti3+ ions. The conductivity of those alkali doped titanium oxides was dependent on the doping level and charge mobility. Non-stoichiometric titanium oxides were produced by reduction of titanium dioxide in a hydrogen atmosphere at 800°C to 1000°C for 2 to 6 hours. The reduced titanium oxides showed better stability with respect to conductivity at ambient condition when compared with the Na or Li doped samples. Conductive coatings were prepared by coating titanium precursors on insulating core materials like SiO2, Al2O3 or mica. The titania coating was made by hydrolysis of titanyl sulfate (TiOSO 4) followed by a reduction procedure to form reduced titanium oxide. The reduced titanium oxides are highly conductive. A uniform coating of titanium oxides on alumina cores was successfully produced. The conductivity of coated powder composites was a function of coating quantity and hydrolysis reaction temperature. The conductivity of the powder as a function of structure, composition, temperature, frequency and

  19. Nano-scale composition of commercial white powders for development of latent fingerprints on adhesives.

    PubMed

    Jones, B J; Reynolds, A J; Richardson, M; Sears, V G

    2010-09-01

    Titanium dioxide based powders are regularly used in the development of latent fingerprints on dark surfaces. For analysis of prints on adhesive tapes, the titanium dioxide can be suspended in a surfactant and used in the form of a powder suspension. Commercially available products, whilst having nominally similar composition, show varying levels of effectiveness of print development, with some powders adhering to the background as well as the print. X-ray fluorescence (XRF), analytical transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and laser particle sizing of the fingerprint powders show TiO(2) particles with a surrounding coating, tens of nanometres thick, consisting of Al and Si rich material, with traces of sodium and sulphur. Such aluminosilicates are commonly used as anti-caking agents and to aid adhesion or functionality of some fingerprint powders; however, the morphology, thickness, coverage and composition of the aluminosilicates are the primary differences between the white powder formulations and could be related to variation in the efficacy of print development. Copyright © 2009 Forensic Science Society. All rights reserved.

  20. pH-resistant titania hybrid organic-inorganic sol-gel coating for solid-phase microextraction of polar compounds.

    PubMed

    Li, Xiujuan; Gao, Jie; Zeng, Zhaorui

    2007-05-02

    A novel titania-hydroxy-terminated silicone oil (titania-OH-TSO) sol-gel coating was developed for solid-phase microextraction of polar compounds. In general, titania-based sol-gel reaction is very fast and need to be decelerated by the use of suitable chelating agents. But in the present work, a judiciously designed sol solution ingredients was used to create the titania-OH-TSO coating without the addition of any chelating agent, which simplified the sol-gel procedure. Thanks to the variety of titania's adsorption sites and their acid-base characteristics, aromatic amines, phenols and polycyclic aromatic hydrocarbons were efficiently extracted and preconcentrated from aqueous samples followed by thermal desorption and GC analysis. The newly developed sol-gel hybrid titania coating demonstrated excellent pH stability, and retained its extraction characteristics intact even after continuous rinsing with a 3 M HCl or NaOH solution for 12 h. Furthermore, it could withstand temperatures as high as 320 degrees C. Practical application was demonstrated through the analysis of six aromatic amines in dye process wastewater. A linearity of four orders of magnitude was obtained with correlation coefficient better than 0.9982. The detection limits ranged from 0.22 to 0.84 microg L(-1) and the repeatability of the measurements was <7.0%. The recoveries of these compounds studied in the wastewater were in the ranges 83.6-101.4%, indicating the method accuracy.

  1. Correlation of lattice defects and thermal processing in the crystallization of titania nanotube arrays

    NASA Astrophysics Data System (ADS)

    Hosseinpour, Pegah M.; Yung, Daniel; Panaitescu, Eugen; Heiman, Don; Menon, Latika; Budil, David; Lewis, Laura H.

    2014-12-01

    Titania nanotubes have the potential to be employed in a wide range of energy-related applications such as solar energy-harvesting devices and hydrogen production. As the functionality of titania nanostructures is critically affected by their morphology and crystallinity, it is necessary to understand and control these factors in order to engineer useful materials for green applications. In this study, electrochemically-synthesized titania nanotube arrays were thermally processed in inert and reducing environments to isolate the role of post-synthesis processing conditions on the crystallization behavior, electronic structure and morphology development in titania nanotubes, correlated with the nanotube functionality. Structural and calorimetric studies revealed that as-synthesized amorphous nanotubes crystallize to form the anatase structure in a three-stage process that is facilitated by the creation of structural defects. It is concluded that processing in a reducing gas atmosphere versus in an inert environment provides a larger unit cell volume and a higher concentration of Ti3+ associated with oxygen vacancies, thereby reducing the activation energy of crystallization. Further, post-synthesis annealing in either reducing or inert atmospheres produces pronounced morphological changes, confirming that the nanotube arrays thermally transform into a porous morphology consisting of a fragmented tubular architecture surrounded by a network of connected nanoparticles. This study links explicit data concerning morphology, crystallization and defects, and shows that the annealing gas environment determines the details of the crystal structure, the electronic structure and the morphology of titania nanotubes. These factors, in turn, impact the charge transport and consequently the functionality of these nanotubes as photocatalysts.

  2. Novelties of combustion synthesized titania ultrafiltration membrane in efficient removal of methylene blue dye from aqueous effluent.

    PubMed

    Doke, Suresh M; Yadav, Ganapati D

    2014-12-01

    In this study, titania nanoparticles were synthesized by combustion and used to make ultrafiltration membrane. Characteristics of titania membranes such as textural evaluation, surface morphology, pure water permeability and protein rejection were investigated. Titania membrane sintered at 450 °C showed pure water permeability 11 × 10−2 L h−1 m−2 kPa−1 and 76% protein rejection. The membrane presented good water flux and retention properties with regards to protein and methylene blue dye. Ultrafiltration process was operated at lower pressure (100 kPa) and showed 99% removal of methylene blue using adsorptive micellar flocculation at sodium dodecyl sulfate concentration below its critical micellar concentration. Ferric chloride was used as the coagulant. The method of making titania membrane and its use are new. These studies can be extended to other dyes and pollutants.

  3. Sol-gel synthesis and characterisation of nano-scale hydroxyapatite

    NASA Astrophysics Data System (ADS)

    Bilton, M.; Brown, A. P.; Milne, S. J.

    2010-07-01

    Hydroxyapatite (HAp) forms the main mineral component of bone and teeth. This naturally occurring HAp is in the form of nano-metre sized crystallites of Ca10(PO4)6(OH)2 that contain a number of cation and anion impurities, for example CO32-, F-, Na+, Mg2+ and Sr2+. Synthetic nano-sized HAp particles exhibit favourable biocompatibility and bioactivity and in order to better match the composition to natural HAp there is great interest in producing a range of chemically modified powders. In this study, two HAp powders have been synthesised via a water-based low-temperature sol-gel method and a third, commercial powder from Sigma-Aldrich have been analysed. Subsequent powder calcination has been carried out within the temperature range of 500-700 °C and the products characterised by bulk chemical analysis, X-ray diffraction and electron microscopy. Energy dispersive X-ray spectroscopy (EDX) in the TEM has been used to assess the composition of individual HAp particles. In order to do this accurately it is first necessary to account for the sensitivity of the HAp structure and composition to irradiation by the high energy electron beam of the TEM. This was done by monitoring the estimated Ca/P ratio derived from TEM-EDX of stoichiometric HAp under increasing levels of electron fluence. A fluence threshold (at a given beam energy) was established below which the measured Ca/P ratio can be considered to be stable. Subsequent elemental analysis at or below this threshold has enabled the variation in composition between particles both within and between synthesis batches to be accurately assessed. Compositional variability between particles is also evident, even in the commercial powder, but is far greater in the powders prepared by the sol-gel method.

  4. MTA-enriched nanocomposite TiO(2)-polymeric powder coatings support human mesenchymal cell attachment and growth.

    PubMed

    Shi, Wen; Mozumder, Mohammad Sayem; Zhang, Hui; Zhu, Jesse; Perinpanayagam, Hiran

    2012-10-01

    The objective of the study described in this paper was the development of novel polymer/ceramic nanocomposite coatings for implants through the application of ultrafine powder coating technology. Polyester resins were combined with µm-sized TiO(2) (25%) as the biocompatibility agent, nTiO(2) (0.5%) as the flow additive and mineral trioxide aggregates (ProRoot® MTA, 5%) as bioactive ceramics. Ultrafine powders were prepared and applied to titanium to create continuous polymeric powder coatings (PPCs) through the application of electrostatic ultrafine powder coating technology. Energy dispersive x-ray analysis confirmed that MTA had been incorporated into the PPCs, and elemental mapping showed that it had formed small clusters that were evenly distributed across the surface. Scanning electron microscopy (SEM) revealed continuous and smooth, but highly textured surface coatings that contrasted with the scalloped appearance of commercially pure titanium (cpTi) controls. Atomic force microscopy revealed intricate nano-topographies with an abundance of submicron-sized pits and nano-projections, evenly dispersed across their surfaces. Inverted fluorescence microscopy, SEM and cell counts showed that human embryonic palatal mesenchymal cells attached and spread out onto PPC and MTA-enriched PPCs within 24 h. Mitochondrial enzyme activity measured viable and metabolically active cells on all of the surfaces. After 72 h of growth, cell counts and metabolic activity were significantly higher (P < 0.05) on the grey-MTA enriched PPC surfaces, than on unmodified PPC and cpTi. The novel polymer/ceramic nanocomposites that were created with ultrafine powder coating technology were continuous, homogenous and nano-rough coatings that enhanced human mesenchymal cell attachment and growth.

  5. Evaluation of the effects of nano-TiO2 on bioactivity and mechanical properties of nano bioglass-P3HB composite scaffold for bone tissue engineering.

    PubMed

    Bakhtiyari, Sanaz Soleymani Eil; Karbasi, Saeed; Monshi, Ahmad; Montazeri, Mahbobeh

    2016-01-01

    To emulate bone structure, porous composite scaffold with suitable mechanical properties should be designed. In this research the effects of nano-titania (nTiO2) on the bioactivity and mechanical properties of nano-bioglass-poly-3-hydroxybutyrate (nBG/P3HB)-composite scaffold were evaluated. First, nBG powder was prepared by melting method of pure raw materials at a temperature of 1400 °C and then the porous ceramic scaffold of nBG/nTiO2 with 30 wt% of nBG containing different weight ratios of nTiO2 (3, 6, and 9 wt% of nTiO2 with grain size of 35-37 nm) was prepared by using polyurethane sponge replication method. Then the scaffolds were coated with P3HB in order to increase the scaffold's mechanical properties. Mechanical strength and modulus of scaffolds were improved by adding nTiO2 to nBG scaffold and adding P3HB to nBG/nTiO2 composite scaffold. The results of the compressive strength and porosity tests showed that the best scaffold is 30 wt% of nBG with 6 wt% of nTiO2 composite scaffold immersed for 30 s in P3HB with 79.5-80 % of porosity in 200-600 μm, with a compressive strength of 0.15 MPa and a compressive modulus of 30 MPa, which is a good candidate for bone tissue engineering. To evaluate the bioactivity of the scaffold, the simulated body fluid (SBF) solution was used. The best scaffold with 30 wt% of nBG, 6 wt% of P3HB and 6 wt% of nTiO2 was immersed in SBF for 4 weeks at an incubation temperature of 37 °C. The bioactivity of the scaffolds was characterized by AAS, SEM, EDXA and XRD. The results of bioactivity showed that bone-like apatite layer formed well at scaffold surface and adding nTiO2 to nBG/P3HB composite scaffold helped increase the bioactivity rate.

  6. Preparation and Characterization of Nano-CL-20 Explosive

    NASA Astrophysics Data System (ADS)

    Bayat, Yadollah; Zeynali, Vida

    2011-10-01

    Nano-CL-20 was prepared via precipitative crystallization by spraying a solution of CL-20 in a solvent (ethyl acetate) into a nonsolvent (isooctane). Scanning electron microscopy (SEM) and X-ray powder diffraction (XRD) were used to characterize the appearance and the size of the particles. The results revealed that nano-CL-20 particles have the shape of spheres or ellipsoids with an average size of 95 nm. Due to their small diameter and high surface energy, the particles tended to agglomerate. Impact sensitivity of nanosize CL-20 was decreased in comparison to micrometer-size CL-20.

  7. In vitro toxicity test of nano-sized magnesium oxide synthesized via solid-phase transformation

    NASA Astrophysics Data System (ADS)

    Zheng, Jun; Zhou, Wei

    2018-04-01

    Nano-sized magnesium oxide (MgO) has been a promising potential material for biomedical pharmaceuticals. In the present investigation, MgO nanoparticles synthesized through in-situ solid-phase transformation based on the previous work (nano-Mg(OH)2 prepared by precipitation technique) using magnesium nitrate and sodium hydroxide. The phase structure and morphology of the MgO nanoparticles are characterized by X-ray powder diffraction (XRD), selected area electronic diffraction (SAED) and transmission electron microscopy (TEM) respectively. In vitro hemolysis tests are adopted to evaluate the toxicity of the synthesized nano-MgO. The results evident that nano-MgO with lower concentration is slightly hemolytic, and with concentration increasing nano-MgO exhibit dose-responsive hemolysis.

  8. CdO-NPs; synthesis from 1D new nano Cd coordination polymer, characterization and application as anti-cancer drug for reducing the viability of cancer cells

    NASA Astrophysics Data System (ADS)

    Afzalian Mend, Behnaz; Delavar, Mahmoud; Darroudi, Majid

    2017-04-01

    The hexagonal CdO nano-particles (CdO-NPs) was prepared using new nano Cd coordination polymer, [Cd(NO3)(bipy)(pzca)]n (1) as a precursor, through direct calcination process at 500 °C. The precursor (1) was synthesized by sonochemical method. The new nano compound (1) was characterized by IR spectroscopy, elemental analyses, X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and thermal gravimetric analyses. The structure of nano coordination polymer was determined by comparing the XRD pattern of nano and single-crystal of compound (1). The nano CdO was characterized by scanning electron microscopy (SEM) and X-ray powder diffraction (XRD). In addition, the activity and efficiency of nano CdO as an anti-cancer drug was studied on cancer cells with different concentration. The results shows that the viability of cancer cells reduced above 2 μg/mL of CdO-NPs concentration.

  9. Synthesis of Nano Sized Cr2AlC Powders by Molten Salt Method.

    PubMed

    Xiao, Dan; Zhu, Jianfeng; Wang, Fen; Tang, Yi

    2015-09-01

    Cr2AlC powders were successfully synthesized by molten salt method using Cr, Al and C as starting materials. The effects of the process parameters and amount of Al addition on the purity of the Cr2AlC powders were also investigated in details. The formation mechanism of Cr2AlC powders was investigated by XRD and DSC. The results indicated that intermediates of Cr7C3 and Cr- Al intermetallics, such as CrAl17, Cr2Al, Cr2Al8, were formed by the reactions among the initial elements, then the intermediates gradually transformed to Cr2AlC. From the fixed composition of Cr:Al:C = 2:1.2:1, high purity Cr2AlC powders could be obtained with an inorganic salt KCl as a solvent at 1250 degrees C for 60 min under argon atmosphere which was lower than that (generally 1450 degrees C) of conventional solid state reaction.

  10. Electrodeposition of titania and barium titanate thin films for high dielectric applications

    NASA Astrophysics Data System (ADS)

    Roy, Biplab Kumar

    In order to address the requirement of a low-temperature low-cost cost processing for depositing high dielectric constant ceramic films for applications in embedded capacitor and flexible electronics technology, two different chemical bath processes, namely, thermohydrolytic deposition (TD) and cathodic electrodeposition (ED) have been exploited to generate titania thin films. In thermohydrolytic deposition technique, titania films were generated from acidic aqueous solution of titanium chloride on F: SnO2 coated glass and Si substrates by temperature assisted hydrolysis mechanism. On the other hand, in cathodic electrodeposition, in-situ electro-generation of hydroxyl ions triggered a fast deposition of titania on conductive substrates such as copper and F: SnO2 coated glass from peroxotitanium solution at low temperatures (˜0°C). In both techniques, solution compositions affected the morphology and crystallinity of the films. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques have been employed to perform such characterization. As both processes utilized water as solvent, the as-deposited films contained hydroxyl ligand or physically adsorbed water molecules in the titania layer. Besides that, electrodeposited films contained peroxotitanium bonds which were characterized by FTIR studies. Although as-electrodeposited titania films were X-ray amorphous, considerable crystallinity could be generated by heat treatment. The films obtained from both the processes showed v moderately high dielectric constant (ranging from 9-30 at 100 kHz) and high breakdown voltage (0.09-0.15 MV/cm) in electrical measurements. To further improve the dielectric constant, electrodeposited titania films were converted to barium titanate films in high pH barium ion containing solution at 80-90°C. The resultant film contained cubic crystalline barium titanate verified by XRD analysis. Simple low-temperature hydrothermal technique of conversion worked

  11. Hydrogen storage properties of nano-structural carbon and metal hydrides composites

    NASA Astrophysics Data System (ADS)

    Miyaoka, Hiroki; Ichikawa, Takayuki; Isobe, Shigehito; Fujii, Hironobu

    2006-08-01

    Thermodynamic and structural properties of some ball-milled mixtures composed of the hydrogenated nanostructural carbon (C nanoH x) and metal hydride (MH; M=Li, Na, Mg and Ca) were examined from thermal desoroption mass spectroscopy and powder X-ray diffraction, respectively. The results showed that the hydrogen desorption temperatures are significantly lowered from those of each hydride (C nanoH x, MH) in the composites. This indicates that a new type of interaction exists between C nanoH x and MH, which destabilizes C-H and/or M-H bonding as well. Therefore, the above Metal-C-H system would be recognized as a new family of hydrogen storage materials.

  12. Evaluation the pozzolanic reactivity of sonochemically fabricated nano natural pozzolan.

    PubMed

    Askarinejad, Azadeh; Pourkhorshidi, Ali Reza; Parhizkar, Tayebeh

    2012-01-01

    Natural pozzolans are appropriate supplementary cementitious materials in cement and concrete industry. A simple sonochemical method was developed to synthesize nanostructures of natural pozzolan. Chemical composition, crystallinity, morphology and reactivity of the natural pozzolan samples were compared before and after the sonochemical process, by using powder X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Thermal Gravimetry and Differential Thermal Analysis (TG/DTA). Compressive strength tests were performed to evaluate the properties of blended cements incorporating nano natural pozzolan. Under optimized conditions, the nano natural pozzolans showed a superior reactivity as compared with the bulk natural pozzolan. Also higher compressive strength was obtained for the cement specimen incorporating nano natural pozzolan. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Hydrogen sulfide conversion with nanophase titania

    DOEpatents

    Beck, Donald D.; Siegel, Richard W.

    1996-01-01

    A process for disassociating H.sub.2 S in a gaseous feed using an improved catalytic material in which the feed is contacted at a temperature of at least about 275.degree. C. with a catalyst of rutile nanocrystalline titania having grain sizes in the range of from about 1 to about 100 nanometers. Other transition metal catalysts are disclosed, each of nanocrystalline material with grain sizes in the 1-100 nm range.

  14. [Influence on mechanical properties and microstructure of nano-zirconia toughened alumina ceramics with nano-zirconia content].

    PubMed

    Wang, Guang-Kui; Kang, Hong; Bao, Guang-Jie; Lv, Jin-Jun; Gao, Fei

    2006-10-01

    To investigate the mechanical properties and microstructure of nano -zirconia toughened alumina ceramics with variety of nano-zirconia content in centrifugal infiltrate casting processing of dental all-ceramic. Composite powder with different ethanol-water ratio, obtained serosity from ball milling and centrifugal infiltrate cast processing of green, then sintered at 1 450 degrees C for 8 h. The physical and mechanical properties of the sintered sample after milling and polishing were tested. Microstructures of the surface and fracture of the sintered sample were investigated by SEM. The experimental results showed that there had statistical significience (P < 0.01) on static three-point flexure strength and Vickers Hardness in three kinds of different nano-zirconia content sintered sample. Fracture toughness of 20% group was different from other two groups, while 10% group had not difference from 30% group (P < 0.05). The mechanical properties of this ceramic with 20% nano-zirconia was the best of the three, the static three-point flexure strength was (433 +/- 19) MPa and fracture toughness was (7.50 +/- 0.56) MPa x min 1/2. The intra/inter structure, fracture of intragranular and intergranular on the surface and fracture of sintered sample in microstrucre was also found. Intra/inter structure has strengthen toughness in ceramics. It has better toughness with 20% nano-zirconia, is suitable dental all-ceramic restoratives.

  15. Impact of the titania nanostructure on charge transport and its application in hybrid solar cells

    NASA Astrophysics Data System (ADS)

    Koffman-Frischknecht, Alejandro; Gonzalez, Fernando; Plá, Juan; Violi, Ianina; Soler-Illia, Galo J. A. A.; Perez, M. Dolores

    2018-02-01

    Porous titania films are widely studied in a number of optoelectronic applications due to its favorable optical and electronic characteristics. Mesoporous titania thin films (MTTFs) with tunable pore size, pore order, accessibility and crystallinity are of interest in electronic devices due to the potential for optimization of the desired characteristics for charge separation and carrier transport. In this work, several MTTFs were prepared by sol-gel chemistry with different structural properties tuned by post-synthesis thermal treatment. The effect of the structural properties (pore diameter, order and accessibility) on the electrical properties of the material was studied by films fabrication onto a transparent conducting electrode, ITO, such that it enables optoelectronic applications. The performance as photoanode was explored by the fabrication of hybrid polymer (P3HT): titania solar cells. Not only does structural properties affect polymer impregnation inside the titania pores as expected and hence impacts charge separation at the interface, but also the thermal treatment affects crystallinity and the films electronic properties. A more complete picture about the electronic properties of the different MTTFs prepared in this work was studied by mobility measurement by space charge limited current and impedance spectroscopy.

  16. Synthesis and characterization of Ni NPs-doped silica-titania nanocomposites: structural, optical and photocatalytic properties

    NASA Astrophysics Data System (ADS)

    Islam, S.; Bidin, N.; Osman, S. S.; Krishnan, G.; Salim, A. A.; Riaz, S.; Suan, L. P.; Naseem, S.; Sanagi, M. M.

    2017-01-01

    The synthesis of Ni-doped silica-titania nanocomposite is performed by sol-gel method. The samples prior and after heat treatment at 300 °C for 1 h are characterized by analytical instrumental techniques. FE-SEM and AFM results indicate the regular morphology with low surface roughness without any cracks. EDX analysis verifies the formation of nanocomposites. XRD of the films reveals crystalline titania phases after annealing at 300 °C. The FTIR confirms the bond linkage between silica, titania and nickel molecules. High surface area 155 m2/g, pore volume of 0.2 cm3/g and pore diameter of 48.10 Å are obtained after heat treatment. The magnetic results show that the composite content is reminiscent of ferromagnetic hysteresis loop, with remanence magnetization Mr of 45.35 and 13.20 emu/g for both samples. The organic dye phenol red is used for the evaluation of photocatalytic activity of the synthesized magnetic material. The homogeneous surface morphology, crystalline nature, good solubility of magnetic nanoparticles into the silica-titania matrix show that the Ni/SiO2-TiO2 magnetic photocatalyst can be efficient and reusable.

  17. Multistack integration of three-dimensional hyperbranched anatase titania architectures for high-efficiency dye-sensitized solar cells.

    PubMed

    Wu, Wu-Qiang; Xu, Yang-Fan; Rao, Hua-Shang; Su, Cheng-Yong; Kuang, Dai-Bin

    2014-04-30

    An unprecedented attempt was conducted on suitably functionalized integration of three-dimensional hyperbranched titania architectures for efficient multistack photoanode, constructed via layer-by-layer assembly of hyperbranched hierarchical tree-like titania nanowires (underlayer), branched hierarchical rambutan-like titania hollow submicrometer-sized spheres (intermediate layer), and hyperbranched hierarchical urchin-like titania micrometer-sized spheres (top layer). Owing to favorable charge-collection, superior light harvesting efficiency and extended electron lifetime, the multilayered TiO2-based devices showed greater J(sc) and V(oc) than those of a conventional TiO2 nanoparticle (TNP), and an overall power conversion efficiency of 11.01% (J(sc) = 18.53 mA cm(-2); V(oc) = 827 mV and FF = 0.72) was attained, which remarkably outperformed that of a TNP-based reference cell (η = 7.62%) with a similar film thickness. Meanwhile, the facile and operable film-fabricating technique (hydrothermal and drop-casting) provides a promising scheme and great simplicity for high performance/cost ratio photovoltaic device processability in a sustainable way.

  18. Hybrid Drug Delivery Patches Based on Spherical Cellulose Nanocrystals and Colloid Titania-Synthesis and Antibacterial Properties.

    PubMed

    Evdokimova, Olga L; Svensson, Fredric G; Agafonov, Alexander V; Håkansson, Sebastian; Seisenbaeva, Gulaim A; Kessler, Vadim G

    2018-04-08

    Spherical cellulose nanocrystal-based hybrids grafted with titania nanoparticles were successfully produced for topical drug delivery. The conventional analytical filter paper was used as a precursor material for cellulose nanocrystals (CNC) production. Cellulose nanocrystals were extracted via a simple and quick two-step process based on first the complexation with Cu(II) solution in aqueous ammonia followed by acid hydrolysis with diluted H₂SO₄. Triclosan was selected as a model drug for complexation with titania and further introduction into the nanocellulose based composite. Obtained materials were characterized by a broad variety of microscopic, spectroscopic, and thermal analysis methods. The drug release studies showed long-term release profiles of triclosan from the titania based nanocomposite that agreed with Higuchi model. The bacterial susceptibility tests demonstrated that released triclosan retained its antibacterial activity against Escherichia coli and Staphylococcus aureus . It was found that a small amount of titania significantly improved the antibacterial activity of obtained nanocomposites, even without immobilization of model drug. Thus, the developed hybrid patches are highly promising candidates for potential application as antibacterial agents.

  19. Antimicrobial function of Nd3+-doped anatase titania-coated nickel ferrite composite nanoparticles: a biomaterial system.

    PubMed

    Rana, S; Rawat, J; Sorensson, M M; Misra, R D K

    2006-07-01

    The present study describes and makes a relative comparison of the antimicrobial function of undoped and neodymium-doped titania coated-nickel ferrite composite nanoparticles processed by uniquely combining the reverse micelle and chemical hydrolysis approaches. This methodology facilitates the formation of undoped and doped photocatalytic titania shells and a magnetic ferrite core. The ferrite core is needed to help in the removal of particles from the sprayed surface using a small magnetic field. Doping of the titania shell with neodymium significantly enhances the photocatalytic and anti-microbial function of the core-shell composite nanoparticles without influencing the magnetic characteristics of the nickel ferrite core. The increased performance is believed to be related to the inhibition of electron-hole recombination and a decrease in the band gap energy of titania. The retention of magnetic strength ensures controlled movement of the composite nanoparticles by the magnetic field, facilitating their application as removable anti-microbial photocatalyst nanoparticles. The consistent behavior of the composite nanoparticles points to the viability of the synthesis process adopted.

  20. Optimization of Maghemite (γ-Fe2O3) Nano-Powder Mixed micro-EDM of CoCrMo with Multiple Responses Using Gray Relational Analysis (GRA)

    NASA Astrophysics Data System (ADS)

    Mejid Elsiti, Nagwa; Noordin, M. Y.; Idris, Ani; Saed Majeed, Faraj

    2017-10-01

    This paper presents an optimization of process parameters of Micro-Electrical Discharge Machining (EDM) process with (γ-Fe2O3) nano-powder mixed dielectric using multi-response optimization Grey Relational Analysis (GRA) method instead of single response optimization. These parameters were optimized based on 2-Level factorial design combined with Grey Relational Analysis. The machining parameters such as peak current, gap voltage, and pulse on time were chosen for experimentation. The performance characteristics chosen for this study are material removal rate (MRR), tool wear rate (TWR), Taper and Overcut. Experiments were conducted using electrolyte copper as the tool and CoCrMo as the workpiece. Experimental results have been improved through this approach.

  1. Ultrasound-Assisted Synthesis of Titania Nanoparticles, Characterization of Their Thin Films, and Activity in Photooxidation of β-Naphthol

    NASA Astrophysics Data System (ADS)

    Hurain, Syyeda Sana; Habib, Amir; Hussain, Syed Muzammil; Ul-Haq, Noaman

    2015-11-01

    Nanosized titania (TiO2) films and powders were prepared from titanium isopropoxide by ultrasonication then ultrasonic aerosol-assisted chemical vapor deposition (UAACVD). X-ray diffraction (XRD), used to study the crystal structure, phase, and crystallite size of TiO2 samples annealed at 500°C, revealed anatase was the main crystalline phase. Scanning electron microscopy and atomic force microscopy revealed the quasi-spherical morphology of the TiO2 nanoparticles; average size distribution was in the range 20-35 nm. Ultraviolet-visible spectroscopy was used to evaluate the photocatalytic activity of the anatase TiO2, on the basis of efficiency of degradation of β-naphthol. Pure TiO2 nanoparticles synthesized by use of sonication-UAACVD then calcination at 500°C enabled effective photodegradation under UV light. This method of synthesis of TiO2 is superior to the reflux-UAACVD method with titanium isopropoxide as precursor.

  2. Ultrasonic-assisted synthesis of nano lead(II) coordination polymer as precursors for preparation of lead(II) oxide nano-structures: Thermal, optical properties and XRD studies.

    PubMed

    Ghavidelaghdam, Elham; Shahverdizadeh, Gholam Hossein; Motameni Tabatabai, Javad; Mirtamizdoust, Babak

    2018-04-01

    Nano structure of a lead (II) coordination polymer [Pb 2 (C 2 Cl 3 O 2 ) 2 (NO 3 ) 2 (C l2 H 8 N 2 ) 2 ] n (1), has been synthesized by a sonochemical method in different concentrations. The nano particles were characterized by scanning electron microscopy (SEM) X-ray powder diffraction (XRD), FT-IR spectroscopy and elemental analyses. The thermal stability of nano structure is closely investigated via thermal gravimetric (TGA), and compared with crystalline structure. The compounds are then heated to 600 °C to produce PbO nano particles. The resulting PbO is characterized through XRD and SEM analyses. Concentration of initial reagents effects on size and morphology of nano-structured compound 1 have been studied and show that low concentrations of initial reagents decreased particles size and leaded to uniform nano particles morphology. The photoluminescence properties of the prepared compound, as crystalline and as nanoparticles, have been investigated. The result showed a good correlation between the size and emission wavelength. Copyright © 2017. Published by Elsevier B.V.

  3. Synthesis and characterization of nano-hydroxyapatite using Sapindus Mukorossi extract

    NASA Astrophysics Data System (ADS)

    Subha, B.; Prasath, P. Varun; Abinaya, R.; Kavitha, R. J.; Ravichandran, K.

    2015-06-01

    Nano-Hydroxyapatite (HAP) powders were successfully synthesised by hydrothermal method using Sapindus Mukorossi extract as an additive. The structural and morphological analyses of thus synthesised powders were carried out using FT-IR, XRD and FESEM/EDX. The FT-IR spectra confirm the presence of phosphate and hydroxyl groups corresponding to HAP. The XRD analysis reveals the formation of HAP phase and found to reduce the crystallite size with addition of Sapindus Mukorossi extract. The morphology changes from sphere to flake shape by the influence of extract.

  4. The study of the effect of aluminum powders dispersion on the oxidation and kinetic characteristics

    NASA Astrophysics Data System (ADS)

    Gorbenko, T. I.; Gorbenko, M. V.; Orlova, M. P.; Volkov, S. A.

    2017-11-01

    Differential-scanning calorimetry (DSC) and thermogravimetric analysis (TG) were used to study micro-sized aluminum powder ASD-4 and nano-sized powder Alex. The dependence of the oxidation process on the dispersion of the sample particles is shown. The influence of thermogravimetric conditions on the thermal regime of the process was considered, and its kinetic parameters were determined. Calculations of the activation energy and the pre-exponential factor were carried out.

  5. Rapid solid-state metathesis route to transition-metal doped titanias

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Coleman, Nathaniel; Perera, Sujith; Gillan, Edward G., E-mail: edward-gillan@uiowa.edu

    2015-12-15

    Rapid solid-state metathesis (SSM) reactions are often short-lived highly exothermic reactions that yield a molten alkali halide salt that aids in product growth and crystallization. SSM reactions may also produce kinetically stabilized structures due to the short (seconds) reaction times. This report describes the investigation of rapid SSM reactions in the synthesis of transition-metal doped titanias (M–TiO{sub 2}). The dopant targeted compositions were ten mol percent and based on elemental analysis, many of the M–TiO{sub 2} samples were close to this targeted level. Based on surface analysis, some samples showed large enrichment in surface dopant content, particularly chromium and manganesemore » doped samples. Due to the highly exothermic nature of these reactions, rutile structured TiO{sub 2} was observed in all cases. The M–TiO{sub 2} samples are visible colored and show magnetic and optical properties consistent with the dopant in an oxide environment. UV and visible photocatalytic experiments with these visibly colored rutile M–TiO{sub 2} powders showed that many of them are strongly absorbent for methylene blue dye and degrade the dye under both UV and visible light illumination. This work may open up SSM reactions as an alternate non-thermodynamic reaction strategy for dopant incorporation into a wide range of oxide and non-oxides.« less

  6. Hydrogen sulfide conversion with nanophase titania

    DOEpatents

    Beck, D.D.; Siegel, R.W.

    1996-08-20

    A process is described for disassociating H{sub 2}S in a gaseous feed using an improved catalytic material in which the feed is contacted at a temperature of at least about 275 C with a catalyst of rutile nanocrystalline titania having grain sizes in the range of from about 1 to about 100 nanometers. Other transition metal catalysts are disclosed, each of nanocrystalline material with grain sizes in the 1-100 nm range. 5 figs.

  7. Rapid heat treatment for anatase conversion of titania nanotube orthopedic surfaces

    NASA Astrophysics Data System (ADS)

    Bhosle, Sachin M.; Friedrich, Craig R.

    2017-10-01

    The amorphous to anatase transformation of anodized nanotubular titania surfaces has been studied by x-ray diffraction and transmission electron microscopy (TEM). A more rapid heat treatment for conversion of amorphous to crystalline anatase favorable for orthopedic implant applications was demonstrated. Nanotube titania surfaces were fabricated by electrochemical anodization of Ti6Al4V in an electrolyte containing 0.2 wt% NH4F, 60% ethylene glycol and 40% deionized water. The resulting surfaces were systematically heat treated in air with isochronal and isothermal experiments to study the temperature and time dependent transformation respectively. Energy dispersive spectroscopy shows that the anatase phase transformation of TiO2 in the as-anodized amorphous nanotube layer can be achieved in as little as 5 min at 350 °C in contrast to reports of higher temperature and much longer time. Crystallinity analysis at different temperatures and times yield transformation rate coefficients and activation energy for crystalline anatase coalescence. TEM confirms the (101) TiO2 presence within the nanotubes. These results confirm that for applications where amorphous titania nanotube surfaces are converted to crystalline anatase, a 5 min production flow-through heating process could be used instead of a 3 h batch process, reducing time, cost, and complexity.

  8. Facile synthesis of titania nanoparticles coated carbon nanotubes for selective enrichment of phosphopeptides for mass spectrometry analysis.

    PubMed

    Yan, Yinghua; Lu, Jin; Deng, Chunhui; Zhang, Xiangmin

    2013-03-30

    In this work, titania nanoparticles coated carbon nanotubes (denoted as CNTs/TiO2 composites) were synthesized through a facile but effective solvothermal reaction using titanium isopropoxide as the titania source, isopropyl alcohol as the solvent and as the basic catalyst in the presence of hydrophilic carbon nanotubes. Characterizations using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) indicate that the CNTs/TiO2 composites consist of CNT core and a rough outer layer formed by titania nanoparticles (5-10nm). Measurements using wide angle X-ray diffraction (WAXRD), zeta potential and N2 sorption reveal that the titania shell is formed by anatase titania nanoparticles, and the composites have a high specific surface area of about 104 m(2)/g. By using their high surface area and affinity to phosphopeptides, the CNTs/TiO2 composites were applied to selectively enrich phosphopeptides for mass spectrometry analysis. The high selectivity and capacity of the CNTs/TiO2 composites have been demonstrated by effective enrichment of phosphopeptides from digests of phosphoprotein, protein mixtures of β-casein and bovine serum albumin, human serum and rat brain samples. These results foresee a promising application of the novel CNTs/TiO2 composites in the selective enrichment of phosphopeptides. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. High power density cell using nanostructured Sr-doped SmCoO3 and Sm-doped CeO2 composite powder synthesized by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Shimada, Hiroyuki; Yamaguchi, Toshiaki; Suzuki, Toshio; Sumi, Hirofumi; Hamamoto, Koichi; Fujishiro, Yoshinobu

    2016-01-01

    High power density solid oxide electrochemical cells were developed using nanostructure-controlled composite powder consisting of Sr-doped SmCoO3 (SSC) and Sm-doped CeO2 (SDC) for electrode material. The SSC-SDC nano-composite powder, which was synthesized by spray pyrolysis, had a narrow particle size distribution (D10, D50, and D90 of 0.59, 0.71, and 0.94 μm, respectively), and individual particles were spherical, composing of nano-size SSC and SDC fragments (approximately 10-15 nm). The application of the powder to a cathode for an anode-supported solid oxide fuel cell (SOFC) realized extremely fine cathode microstructure and excellent cell performance. The anode-supported SOFC with the SSC-SDC cathode achieved maximum power density of 3.65, 2.44, 1.43, and 0.76 W cm-2 at 800, 750, 700, and 650 °C, respectively, using humidified H2 as fuel and air as oxidant. This result could be explained by the extended electrochemically active region in the cathode induced by controlling the structure of the starting powder at the nano-order level.

  10. Encapsulation of antigen-loaded silica nanoparticles into microparticles for intradermal powder injection.

    PubMed

    Deng, Yibin; Mathaes, Roman; Winter, Gerhard; Engert, Julia

    2014-10-15

    Epidermal powder immunisation (EPI) is being investigated as a promising needle-free delivery methods for vaccination. The objective of this work was to prepare a nanoparticles-in-microparticles (nano-in-micro) system, integrating the advantages of nanoparticles and microparticles into one vaccine delivery system for epidermal powder immunisation. Cationic mesoporous silica nanoparticles (MSNP-NH2) were prepared and loaded with ovalbumin as a model antigen. Loading was driven by electrostatic interactions. Ovalbumin-loaded silica nanoparticles were subsequently formulated into sugar-based microparticles by spray-freeze-drying. The obtained microparticles meet the size requirement for EPI. Confocal microscopy was used to demonstrate that the nanoparticles are homogeneously distributed in the microparticles. Furthermore, the silica nanoparticles in the dry microparticles can be re-dispersed in aqueous solution showing no aggregation. The recovered ovalbumin shows integrity compared to native ovalbumin. The present nano-in-micro system allows (1) nanoparticles to be immobilized and finely distributed in microparticles, (2) microparticle formation and (3) re-dispersion of nanoparticles without subsequent aggregation. The nanoparticles inside microparticles can (1) adsorb proteins to cationic shell/surface voids in spray-dried products without detriment to ovalbumin stability, (2) deliver antigens in nano-sized modes to allow recognition by the immune system. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Achieving significantly enhanced visible-light photocatalytic efficiency using a polyelectrolyte: the composites of exfoliated titania nanosheets, graphene, and poly(diallyl-dimethyl-ammonium chloride)

    NASA Astrophysics Data System (ADS)

    Zhang, Qian; An, Qi; Luan, Xinglong; Huang, Hongwei; Li, Xiaowei; Meng, Zilin; Tong, Wangshu; Chen, Xiaodong; Chu, Paul K.; Zhang, Yihe

    2015-08-01

    A high-performance visible-light-active photocatalyst is prepared using the polyelectrolyte/exfoliated titania nanosheet/graphene oxide (GO) precursor by flocculation followed by calcination. The polyelectrolyte poly(diallyl-dimethyl-ammonium chloride) serves not only as an effective binder to precipitate GO and titania nanosheets, but also boosts the overall performance of the catalyst significantly. Unlike most titania nanosheet-based catalysts reported in the literature, the composite absorbs light in the UV-Vis-NIR range. Its decomposition rate of methylene blue is 98% under visible light. This novel strategy of using a polymer to enhance the catalytic performance of titania nanosheet-based catalysts affords immense potential in designing and fabricating next-generation photocatalysts with high efficiency.A high-performance visible-light-active photocatalyst is prepared using the polyelectrolyte/exfoliated titania nanosheet/graphene oxide (GO) precursor by flocculation followed by calcination. The polyelectrolyte poly(diallyl-dimethyl-ammonium chloride) serves not only as an effective binder to precipitate GO and titania nanosheets, but also boosts the overall performance of the catalyst significantly. Unlike most titania nanosheet-based catalysts reported in the literature, the composite absorbs light in the UV-Vis-NIR range. Its decomposition rate of methylene blue is 98% under visible light. This novel strategy of using a polymer to enhance the catalytic performance of titania nanosheet-based catalysts affords immense potential in designing and fabricating next-generation photocatalysts with high efficiency. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr03256c

  12. Pulsed supercritical synthesis of anatase TiO₂ nanoparticles in a water-isopropanol mixture studied by in situ powder X-ray diffraction.

    PubMed

    Rostgaard Eltzholtz, Jakob; Tyrsted, Christoffer; Ørnsbjerg Jensen, Kirsten Marie; Bremholm, Martin; Christensen, Mogens; Becker-Christensen, Jacob; Brummerstedt Iversen, Bo

    2013-03-21

    A new step in supercritical nanoparticle synthesis, the pulsed supercritical synthesis reactor, is investigated in situ using synchrotron powder X-ray diffraction (PXRD) to understand the formation of nanoparticles in real time. This eliminates the common problem of transferring information gained during in situ studies to subsequent laboratory reactor conditions. As a proof of principle, anatase titania nanoparticles were synthesized in a 50/50 mixture of water and isopropanol near and above the critical point of water (P = 250 bar, T = 300, 350, 400, 450, 500 and 550 °C). The evolution of the reaction product was followed by sequentially recording PXRD patterns with a time resolution of less than two seconds. The crystallite size of titania is found to depend on both temperature and residence time, and increasing either parameter leads to larger crystallites. A simple adjustment of either temperature or residence time provides a direct method for gram scale production of anatase nanoparticles of average crystallite sizes between 7 and 35 nm, thus giving the option of synthesizing tailor-made nanoparticles. Modeling of the in situ growth curves using an Avrami growth model gave an activation energy of 66(19) kJ mol(-1) for the initial crystallization. The in situ PXRD data also provide direct information about the size dependent macrostrain in the nanoparticles and with decreasing crystallite size the unit cell contracts, especially along the c-direction. This agrees well with previous ex situ results obtained for hydrothermal synthesis of titania nanoparticles.

  13. Sol-Gel-Based Titania-Silica Thin Film Overlay for Long Period Fiber Grating-Based Biosensors.

    PubMed

    Chiavaioli, Francesco; Biswas, Palas; Trono, Cosimo; Jana, Sunirmal; Bandyopadhyay, Somnath; Basumallick, Nandini; Giannetti, Ambra; Tombelli, Sara; Bera, Susanta; Mallick, Aparajita; Baldini, Francesco

    2015-12-15

    An evanescent wave optical fiber biosensor based on titania-silica-coated long period grating (LPG) is presented. The chemical overlay, which increases the refractive index (RI) sensitivity of the sensor, consists of a sol-gel-based titania-silica thin film, deposited along the sensing portion of the fiber by means of the dip-coating technique. Changing both the sol viscosity and the withdrawal speed during the dip-coating made it possible to adjust the thickness of the film overlay, which is a crucial parameter for the sensor performance. After the functionalization of the fiber surface using a methacrylic acid/methacrylate copolymer, an antibody/antigen (IgG/anti-IgG) assay was carried out to assess the performance of sol-gel based titania-silica-coated LPGs as biosensors. The analyte concentration was determined from the wavelength shift at the end of the binding process and from the initial binding rate. This is the first time that a sol-gel based titania-silica-coated LPG is proposed as an effective and feasible label-free biosensor. The specificity of the sensor was validated by performing the same model assay after spiking anti-IgG into human serum. With this structured LPG, detection limits of the order of tens of micrograms per liter (10(-11) M) are attained.

  14. Feasibility of Plasma Treated Clay in Clay/Polymer Nanocomposites Powders for use Laser Sintering (LS)

    NASA Astrophysics Data System (ADS)

    Almansoori, Alaa; Seabright, Ryan; Majewski, C.; Rodenburg, C.

    2017-05-01

    The addition of small quantities of nano-clay to nylon is known to improve mechanical properties of the resulting nano-composite. However, achieving a uniform dispersion and distribution of the clay within the base polymer can prove difficult. A demonstration of the fabrication and characterization of plasma-treated organoclay/Nylon12 nanocomposite was carried out with the aim of achieving better dispersion of clay platelets on the Nylon12 particle surface. Air-plasma etching was used to enhance the compatibility between clays and polymers to ensure a uniform clay dispersion in composite powders. Downward heat sintering (DHS) in a hot press is used to process neat and composite powders into tensile and XRD specimens. Morphological studies using Low Voltage Scanning Electron Microscopy (LV-SEM) were undertaken to characterize the fracture surfaces and clay dispersion in powders and final composite specimens. Thermogravimetric analysis (TGA) testing performed that the etched clay (EC) is more stable than the nonetched clay (NEC), even at higher temperatures. The influence of the clay ratio and the clay plasma treatment process on the mechanical properties of the nanocomposites was studied by tensile testing. The composite fabricated from (3% EC/N12) powder showed ~19 % improvement in elastic modulus while the composite made from (3% NEC/N12) powder was improved by only 14%). Most notably however is that the variation between tests is strongly reduced when etch clay is used in the composite. We attribute this to a more uniform distribution and better dispersion of the plasma treated clay within polymer powders and ultimately the composite.

  15. Using precipitated Cr on the surface of Cu-Cr alloy powders as catalyst synthesizing CNTs/Cu composite powders by water-assisted CVD

    NASA Astrophysics Data System (ADS)

    Zhou, Honglei; Liu, Ping; Chen, Xiaohong; Bi, Liming; Zhang, Ke; Liu, Xinkuan; Li, Wei; Ma, Fengcang

    2018-02-01

    Given that the conventional catalyst is easily soluble in the matrix to result in the poor performance of the CNTs/Cu composite materials, the Cr nano-particles precipitated on the surface of Cu-Cr particles are first used as catalysts to prepare the CNTs/Cu composite powders by means of water-assisted chemical vapor deposition in situ synthesis. The results show that the morphological difference of the precipitated Cr nano-particle is obvious with the change of solution and aging treatment, and the morphology, length and diameter of the synthetic CNTs are also different. The catalyst of Cr nano-particle has the best morphology and the synthesized CNTs had a good wettability with Cu particles when the Cu-Cr composite powders was solution-treated at 1023 K for 60 min and then was aged at 723 K for 120 min. The length, diameter, yield and purity of the synthesized CNTs can be also affected by the moisture content in the reaction gas. It is the most suitable for the growth of CNTs when the moisture content is 0.4%, and the high purity and defect-free CNTs with the smooth pipe wall, a diameter of 20 ˜ 30 nm and a length of up to 1800 nm can be obtained. The yield of CNTs with the moisture content of 0.4% reached to 138%, which was increased by 119% to compare with that without moisture. In this paper, a feasible technology was offered for the preparation of high performance CNTs/Cu composites.

  16. Dispersed-nanoparticle loading synthesis for monodisperse Au-titania composite particles and their crystallization for highly active UV and visible photocatalysts.

    PubMed

    Sakamoto, Takeshi; Nagao, Daisuke; Noba, Masahiro; Ishii, Haruyuki; Konno, Mikio

    2014-06-24

    Submicrometer-sized amorphous titania spheres incorporating Au nanoparticles (NPs) were prepared in a one-pot synthesis consisting of a sol-gel reaction of titanium(IV) isopropoxide in the presence of chloroauric acid and a successive reduction with sodium borohydride in a mixed solvent of ethanol/acetonitrile. The synthesis was allowed to prepare monodisperse titania spheres that homogeneously incorporated Au NPs with sizes of ca. 7 nm. The Au NP-loaded titania spheres underwent different crystallization processes, including 500 °C calcination in air, high-temperature hydrothermal treatment (HHT), and/or low-temperature hydrothermal treatment (LHT). Photocatalytic experiments were conducted with the Au NP-loaded crystalline titania spheres under irradiation of UV and visible light. A combined process of LHT at 80 °C followed by calcination at 500 °C could effectively crystallize titania spheres maintaining the dispersion state of Au NPs, which led to photocatalytic activity higher than that of commercial P25 under UV irradiation. Under visible light irradiation, the Au NP-titania spheres prepared with a crystallization process of LHT at 80 °C for 6 h showed photocatalytic activity much higher than a commercial product of visible light photocatalyst. Structure analysis of the visible light photocatalysts indicates the importance of prevention of the Au NPs aggregation in the crystallization processes for enhancement of photocatalytic activity.

  17. Sol-gel nano-porous silica-titania thin films with liquid fill for optical interferometric sensors

    NASA Astrophysics Data System (ADS)

    Martin, Andrew J.; Green, Mino

    1990-11-01

    The production of thin films whose refractive index is measurand specific, for use in an interferometric fiber optic chemical sensor, is discussed. The problem of making such coatings has been tackled by a system we have termed the "guest-host" approach, in which an active liquid whose index varies with measurand, is contained within a porous glass host of fixed index. Suitable porous silica-titania glass films have been produced via the sol-gel process. The use of this system enables the index of the glass to be varied, so that the composite index of the liquid filled film can be tailored to that required by the optical system. The sol-gel method developed is based upon the hydrolysis and polymerisation of metal alkoxides, in an acidic aqueous/alcoholic solution. Thin film slab waveguides were deposited in order to measure the light scattering losses, which were found to be typically ''1dB/cm. The porosity of films was studied using a new technique developed in which water adsorption isotherms are plotted using ellipsometry. The pore size was found to be very small of pore diameter in the nanometer range, and the total porosity -1O%. Both of these factors were increased by the removal of residual organic material, using hydrogen peroxide. Finally the use of pH indicator dyes as a liquid fill is discussed, to produce a pH sensor.

  18. Characterization of sodium phenytoin co-gelled with titania for a controlled drug-release system

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lopez, T.; Instituto Nacional de Neurologia y Neurocirugia 'MVS', Av. Insurgentes Sur 3877. Col. La Fama. P.O. Box 14269 Mexico D. F.; Quintana, P.

    2007-08-15

    Sodium phenytoin, C{sub 15}H{sub 11}N{sub 2}NaO{sub 2}, in several concentrations was co-gelled with titania (TiO{sub 2}), by a sol-gel process. This technique is a promising method to encapsulate several drugs, in this case, phenytoin is an anticonvulsant used to control epileptic seizures. Samples were prepared by adding different concentrations (X = 50, 100, 200 and 250 mg per 20 g of titania matrix) of sodium phenytoin (Ph) to a solution of titanium n-butoxide. The resulting titania-Ph-X materials were characterized by transmission electron microscopy (TEM), Fourier transformed infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), and Brunauer-Emmet-Teller (BET) surface areas. The porous nanomaterialsmore » showed a wide range of particle size, from 10 to 210 nm, with a mean pore diameter of 5 nm. X-ray diffraction showed an amorphous structure of the prepared samples.« less

  19. Application of concrete surfaces as novel substrate for immobilization of TiO2 nano powder in photocatalytic treatment of phenolic water.

    PubMed

    Delnavaz, Mohammad; Ayati, Bita; Ganjidoust, Hossein; Sanjabi, Sohrab

    2015-01-01

    In this study, concrete application as a substrate for TiO2 nano powder immobilization in heterogeneous photocatalytic process was evaluated. TiO2 immobilization on the pervious concrete surface was done by different procedures containing slurry method (SM), cement mixed method (CMM) and different concrete sealer formulations. Irradiation of TiO2 was prepared by UV-A and UV-C lamps. Phenolic wastewater was selected as a pollutant and efficiency of the process was determined in various operation conditions including influent phenol concentration, pH, TiO2 concentration, immobilization method and UV lamp intensity. The removal efficiency of photocatalytic process in 4 h irradiation time and phenol concentration ranges of 25-500 mg/L was more than 80 %. Intermediates were identified by GC/Mass and spectrophotometric analysis. According to the results, photocatalytic reactions followed the pseudo-first-order kinetics and can effectively treate phenol under optimal conditions.

  20. Structural Chemistry of Functional Nano-Materials for Environmental Remediation

    NASA Astrophysics Data System (ADS)

    John, Jesse

    Nano minerals and materials have become a focal point of Geoscience research due to the unique physical, chemical, optical, magnetic, electronic, and reactive properties. Many of these desired properties in Nano technology have the potential to impact society by improving remediation, photovoltaics, medicine and the sustainability limits on Earth for an expanding population. Despite the progress made on the discovery, synthesis, and manufacturing of numerous nano-materials, the atomistic cause of their desired properties is poorly understood. To gain a better understanding of the atomic structure of nano materials and their bulk counterparts we combined several crystallographic techniques to solve the crystal structure and performed formative characterization to ascertain the atomistic source of the desired application. These strategies and tools can be used to expedite discovery, development and the goals of the National Nanotechnology Initiative (NNI). This thesis will cover the optimization of the reaction conditions and resolve the atomic structure to produce pure synthetic nano nolanite (SNN) Fe2V3O7OH. The complete structural model of nolanite was described from a bulk mineral to the nano-regime using a combination of single crystal X-ray diffraction (SC-XRD), pair distribution function analysis (PDF) and neutron powder diffraction from synthetic material. Nolanite is isostructural to ferrihydrite, a ubiquitous nano-mineral, both of these mineral structures have been the subject for debate for the last half of century. A comparative study of the isostructural minerals nolanite, akdalaite and ferrihydrite was utilized to address the discrepancies and consolidate the structural models. Lastly, we developed a structural model for nano-crystalline titanium-based material; mono sodium titanate (MST) using high energy total X-ray scattering and PDF coupled with scanning transmission electron microscope (STEM). In the USA we have accumulated over 76000 metric tons

  1. Characterization of gas tunnel type plasma sprayed hydroxyapatite-nanostructure titania composite coatings

    NASA Astrophysics Data System (ADS)

    Yugeswaran, S.; Kobayashi, A.; Ucisik, A. Hikmet; Subramanian, B.

    2015-08-01

    Hydroxyapatite (HA) can be coated onto metal implants as a ceramic biocompatible coating to bridge the growth between implants and human tissue. Meanwhile many efforts have been made to improve the mechanical properties of the HA coatings without affecting its bioactivity. In the present study, nanostructure titania (TiO2) was mixed with HA powder and HA-nanostructure TiO2 composite coatings were produced by gas tunnel type plasma spraying torch under optimized spraying conditions. For this purpose, composition of 10 wt% TiO2 + 90 wt% HA, 20 wt% TiO2 + 80 wt% HA and 30 wt% TiO2 + 70 wt% HA were selected as the feedstock materials. The phase, microstructure and mechanical properties of the coatings were characterized. The obtained results validated that the increase in weight percentage of nanostructure TiO2 in HA coating significantly increased the microhardness, adhesive strength and wear resistance of the coatings. Analysis of the in vitro bioactivity and cytocompatibility of the coatings were done using conventional simulated body fluid (c-SBF) solution and cultured green fluorescent protein (GFP) labeled marrow stromal cells (MSCs) respectively. The bioactivity results revealed that the composite coating has bio-active surface with good cytocompatibility.

  2. Formation and mechanism of nanocrystalline AZ91 powders during HDDR processing

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Liu, Yafen; Fan, Jianfeng, E-mail: fanjianfeng@tyu

    2017-03-15

    Grain sizes of AZ91 alloy powders were markedly refined to about 15 nm from 100 to 160 μm by an optimized hydrogenation-disproportionation-desorption-recombination (HDDR) process. The effect of temperature, hydrogen pressure and processing time on phase and microstructure evolution of AZ91 alloy powders during HDDR process was investigated systematically by X-ray diffraction, optical microscopy, scanning electron microscopy and transmission electron microscopy, respectively. The optimal HDDR process for preparing nanocrystalline Mg alloy powders is hydriding at temperature of 350 °C under 4 MPa hydrogen pressure for 12 h and dehydriding at 350 °C for 3 h in vacuum. A modified unreacted coremore » model was introduced to describe the mechanism of grain refinement of during HDDR process. - Highlights: • Grain size of the AZ91 alloy powders was significantly refined from 100 μm to 15 nm. • The optimal HDDR technology for nano Mg alloy powders is obtained. • A modified unreacted core model of grain refinement mechanism was proposed.« less

  3. In vitro apatite formation on nano-crystalline titania layer aligned parallel to Ti6Al4V alloy substrates with sub-millimeter gap.

    PubMed

    Hayakawa, Satoshi; Matsumoto, Yuko; Uetsuki, Keita; Shirosaki, Yuki; Osaka, Akiyoshi

    2015-06-01

    Pure titanium substrates were chemically oxidized with H2O2 and subsequent thermally oxidized at 400 °C in air to form anatase-type titania layer on their surface. The chemically and thermally oxidized titanium substrate (CHT) was aligned parallel to the counter specimen such as commercially pure titanium (cpTi), titanium alloy (Ti6Al4V) popularly used as implant materials or Al substrate with 0.3-mm gap. Then, they were soaked in Kokubo's simulated body fluid (SBF, pH 7.4, 36.5 °C) for 7 days. XRD and SEM analysis showed that the in vitro apatite-forming ability of the contact surface of the CHT specimen decreased in the order: cpTi > Ti6Al4V > Al. EDX and XPS surface analysis showed that aluminum species were present on the contact surface of the CHT specimen aligned parallel to the counter specimen such as Ti6Al4V and Al. This result indicated that Ti6Al4V or Al specimens released the aluminum species into the SBF under the spatial gap. The released aluminum species might be positively or negatively charged in the SBF and thus can interact with calcium or phosphate species as well as titania layer, causing the suppression of the primary heterogeneous nucleation and growth of apatite on the contact surface of the CHT specimen under the spatial gap. The diffusion and adsorption of aluminum species derived from the half-sized counter specimen under the spatial gap resulted in two dimensionally area-selective deposition of apatite particles on the contact surfaces of the CHT specimen.

  4. A hydrothermal peroxo method for preparation of highly crystalline silica-titania photocatalysts.

    PubMed

    Krivtsov, Igor; Ilkaeva, Marina; Avdin, Viacheslav; Khainakov, Sergei; Garcìa, Jose R; Ordòñez, Salvador; Dìaz, Eva; Faba, Laura

    2015-04-15

    A new completely inorganic method of preparation of silica-titania photocatalyst has been described. It has been established that the addition of silica promotes crystallinity of TiO2 anatase phase. Relative crystallinity and TiO2 crystal size in the silica-titania particles increase with the silica content until SiO2/TiO2 molar ratio of 0.9, but at higher molar ratios they start to decrease. The single-source precursor containing peroxo titanic (PTA) and silicic acids has been proved to be responsible for high crystallinity of TiO2 encapsulated into amorphous silica. It has been proposed that peroxo groups enhance rapid formation of crystalline titania seeds, while silica controls their growth. It has been concluded from the TEM that the most morphologically uniform anatase crystallites covered with SiO2 particles are prepared at SiO2/TiO2 molar ratio of 0.4. This sample, according to (29)Si NMR, also shows the high content of hydroxylated silica Q(3) and Q(2) groups, and it is the most photocatalytically active in UV-assisted decomposition of methylene blue among the tested materials. It has been determined that the increase in the amount of the condensed Q(4) silica in the mixed oxides leads to the decrease in photocatalytic performance of the material, despite its better crystallinity. High crystallinity, low degree of incorporation of Ti atoms in SiO2 in the mixed oxide and adsorption of methylene blue in the vicinity of photoactive sites on the hydroxylated silica have been considered as the main factors determining the high degradation degree of methylene blue in the presence of silica-titania. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. Guided in Situ Polymerization of MEH-PPV in Mesoporous Titania Photoanodes.

    PubMed

    Minar, Norma K; Docampo, Pablo; Fattakhova-Rohlfing, Dina; Bein, Thomas

    2015-05-20

    Incorporation of conjugated polymers into porous metal oxide networks is a challenging task, which is being pursued via many different approaches. We have developed the guided in situ polymerization of poly(2-methoxy-5-(2'-ethylhexyloxy)-p-phenylenevinylene) (MEH-PPV) in porous titania films by means of surface functionalization. The controlled polymerization via the Gilch route was induced by an alkoxide base and by increasing the temperature. The selected and specially designed surface-functionalizing linker molecules mimic the monomer or its activated form, respectively. In this way, we drastically enhanced the amount of MEH-PPV incorporated into the porous titania phase compared to nonfunctionalized samples by a factor of 6. Additionally, photovoltaic measurements were performed. The devices show shunting or series resistance limitations, depending on the surface functionalization prior to in situ polymerization of MEH-PPV. We suggest that the reason for this behavior can be found in the orientation of the grown polymer chains with respect to the titania surface. Therefore, the geometry of the anchoring via the linker molecules is relevant for exploiting the full electronic potential of the conjugated polymer in the resulting hybrid composite. This observation will help to design future synthesis methods for new hybrid materials from conjugated polymers and n-type semiconductors to take full advantage of favorable electronic interactions between the two phases.

  6. Nano-TiO2, ultrasound and sequential nano-TiO2/ultrasonic degradation of N-acetyl-para-aminophenol from aqueous solution.

    PubMed

    Ayanda, Olushola S; Nelana, Simphiwe M; Petrik, Leslie F; Naidoo, Eliazer B

    2017-10-01

    The application of nano-TiO 2 as adsorbent combined with ultrasound for the degradation of N-acetyl-para-aminophenol (AAP) from aqueous solution was investigated. The nano-TiO 2 was characterized by means of powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), and attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR). Experimental results revealed that the adsorption of AAP by nano-TiO 2 fitted the pseudo-second-order kinetic model, the equilibrium could be explained by the Freundlich isotherm and the treatment process is exothermic. The optimum removal efficiency of AAP (128.89 mg/g (77.33%)) was achieved at pH 4 when 0.03 g of nano-TiO 2 was mixed with 50 mL of 100 mg/L AAP aqueous solution at ambient temperature, 60 min contact time, and a stirring speed of 120 rpm. Ultrasound at 20 kHz and pH 3 was favorable and it resulted in 52.61% and 57.43% removal efficiency with and without the addition of nano-TiO 2 , respectively. The degradation of AAP by ultrasound followed by nano-TiO 2 treatment resulted in approximately 99.50% removal efficiency. This study showed that a sequential ultrasound and nano-TiO 2 treatment process could be employed for the removal of AAP or other emerging water and wastewater contaminants.

  7. Si-Ge Nano-Structured with Tungsten Silicide Inclusions

    NASA Technical Reports Server (NTRS)

    Mackey, Jon; Sehirlioglu, Alp; Dynys, Fred

    2014-01-01

    Traditional silicon germanium high temperature thermoelectrics have potential for improvements in figure of merit via nano-structuring with a silicide phase. A second phase of nano-sized silicides can theoretically reduce the lattice component of thermal conductivity without significantly reducing the electrical conductivity. However, experimentally achieving such improvements in line with the theory is complicated by factors such as control of silicide size during sintering, dopant segregation, matrix homogeneity, and sintering kinetics. Samples are prepared using powder metallurgy techniques; including mechanochemical alloying via ball milling and spark plasma sintering for densification. In addition to microstructural development, thermal stability of thermoelectric transport properties are reported, as well as couple and device level characterization.

  8. Toxicological Implications of Released Particulate Matter during Thermal Decomposition of Nano-Enabled Thermoplastics

    PubMed Central

    Watson-Wright, Christa; Singh, Dilpreet; Demokritou, Philip

    2017-01-01

    Nano-enabled thermoplastics are part of the growing market of nano-enabled products (NEPs) that have vast utility in several industries and consumer goods. The use and disposal of NEPs at their end of life has raised concerns about the potential release of constituent engineered nanomaterials (ENMs) during thermal decomposition and their impact on environmental health and safety. To investigate this issue, industrially relevant nano-enabled thermoplastics including polyurethane, polycarbonate, and polypropylene containing carbon nanotubes (0.1 and 3% w/v, respectively), polyethylene containing nanoscale iron oxide (5% w/v), and ethylene vinyl acetate containing nanoscale titania (2 and 5% w/v) along with their pure thermoplastic matrices were thermally decomposed using the recently developed lab based Integrated Exposure Generation System (INEXS). The life cycle released particulate matter (called LCPM) was monitored using real time instrumentation, size fractionated, sampled, extracted and prepared for toxicological analysis using primary small airway epithelial cells to assess potential toxicological effects. Various cellular assays were used to assess reactive oxygen species and total glutathione as measurements of oxidative stress along with mitochondrial function, cellular viability, and DNA damage. By comparing toxicological profiles of LCPM released from polymer only (control) with nano-enabled LCPM, potential nanofiller effects due to the use of ENMs were determined. We observed associations between NEP properties such as the percent nanofiller loading, host matrix, and nanofiller chemical composition and the physico-chemical properties of released LCPM, which were linked to biological outcomes. More specifically, an increase in percent nanofiller loading promoted a toxicological response independent of increasing LCPM dose. Importantly, differences in host matrix and nanofiller composition were shown to enhance biological activity and toxicity of LCPM

  9. Toxicological Implications of Released Particulate Matter during Thermal Decomposition of Nano-Enabled Thermoplastics.

    PubMed

    Watson-Wright, Christa; Singh, Dilpreet; Demokritou, Philip

    2017-01-01

    Nano-enabled thermoplastics are part of the growing market of nano-enabled products (NEPs) that have vast utility in several industries and consumer goods. The use and disposal of NEPs at their end of life has raised concerns about the potential release of constituent engineered nanomaterials (ENMs) during thermal decomposition and their impact on environmental health and safety. To investigate this issue, industrially relevant nano-enabled thermoplastics including polyurethane, polycarbonate, and polypropylene containing carbon nanotubes (0.1 and 3% w/v, respectively), polyethylene containing nanoscale iron oxide (5% w/v), and ethylene vinyl acetate containing nanoscale titania (2 and 5% w/v) along with their pure thermoplastic matrices were thermally decomposed using the recently developed lab based Integrated Exposure Generation System (INEXS). The life cycle released particulate matter (called LCPM) was monitored using real time instrumentation, size fractionated, sampled, extracted and prepared for toxicological analysis using primary small airway epithelial cells to assess potential toxicological effects. Various cellular assays were used to assess reactive oxygen species and total glutathione as measurements of oxidative stress along with mitochondrial function, cellular viability, and DNA damage. By comparing toxicological profiles of LCPM released from polymer only (control) with nano-enabled LCPM, potential nanofiller effects due to the use of ENMs were determined. We observed associations between NEP properties such as the percent nanofiller loading, host matrix, and nanofiller chemical composition and the physico-chemical properties of released LCPM, which were linked to biological outcomes. More specifically, an increase in percent nanofiller loading promoted a toxicological response independent of increasing LCPM dose. Importantly, differences in host matrix and nanofiller composition were shown to enhance biological activity and toxicity of LCPM

  10. Pure and zinc doped nano-hydroxyapatite: Synthesis, characterization, antimicrobial and hemolytic studies

    NASA Astrophysics Data System (ADS)

    Tank, Kashmira P.; Chudasama, Kiran S.; Thaker, Vrinda S.; Joshi, Mihir J.

    2014-09-01

    The structural, antimicrobial, and hemolytic properties and bioactivity have been studied of pure hydroxyapatite (HAP) and zinc doped hydroxyapatite (Zn-HAP) nano-particles for their medical applications. Pure HAP and Zn-HAP nano-particles were synthesized by the surfactant mediated approach. The doping of zinc was estimated by EDAX. The average particle size was determined by applying Scherrer's formula to powdered XRD patterns. The nano-particle morphology was studied by TEM and the presence of various functional groups was identified by FTIR spectroscopy. Good antimicrobial activity of nano-HAP and nano-Zn-HAP was found against five organisms, viz., Pseudomonas aeruginosa and Shigella flexneri as Gram negative as well as Micrococcus luteus, Staphylococcous aureus and Bacillus cereus as Gram positive. The ability of new apatite formation on the surface of pure and doped HAP samples was studied by using Simulated Body Fluid (SBF) in vitro. Hemolytic study indicated that all samples were non-hemolytic and suggesting potential application as bone implant material.

  11. Nanoscale Roughness and Morphology Affect the IsoElectric Point of Titania Surfaces

    PubMed Central

    Borghi, Francesca; Vyas, Varun; Podestà, Alessandro; Milani, Paolo

    2013-01-01

    We report on the systematic investigation of the role of surface nanoscale roughness and morphology on the charging behaviour of nanostructured titania (TiO2) surfaces in aqueous solutions. IsoElectric Points (IEPs) of surfaces have been characterized by direct measurement of the electrostatic double layer interactions between titania surfaces and the micrometer-sized spherical silica probe of an atomic force microscope in NaCl aqueous electrolyte. The use of a colloidal probe provides well-defined interaction geometry and allows effectively probing the overall effect of nanoscale morphology. By using supersonic cluster beam deposition to fabricate nanostructured titania films, we achieved a quantitative control over the surface morphological parameters. We performed a systematical exploration of the electrical double layer properties in different interaction regimes characterized by different ratios of characteristic nanometric lengths of the system: the surface rms roughness Rq, the correlation length ξ and the Debye length λD. We observed a remarkable reduction by several pH units of IEP on rough nanostructured surfaces, with respect to flat crystalline rutile TiO2. In order to explain the observed behavior of IEP, we consider the roughness-induced self-overlap of the electrical double layers as a potential source of deviation from the trend expected for flat surfaces. PMID:23874708

  12. Silica-coated titania and zirconia colloids for subsurface transport field experiments

    USGS Publications Warehouse

    Ryan, Joseph N.; Elimelech, Menachem; Baeseman, Jenny L.; Magelky, Robin D.

    2000-01-01

    Silica-coated titania (TiO2) and zirconia (ZrO2) colloids were synthesized in two sizes to provide easily traced mineral colloids for subsurface transport experiments. Electrophoretic mobility measurements showed that coating with silica imparted surface properties similar to pure silica to the titania and zirconia colloids. Measurements of steady electrophoretic mobility and size (by dynamic light scattering) over a 90-day period showed that the silica-coated colloids were stable to aggregation and loss of coating. A natural gradient field experiment conducted in an iron oxide-coated sand and gravel aquifer also showed that the surface properties of the silica-coated colloids were similar. Colloid transport was traced at μg L-1 concentrations by inductively coupled plasma-atomic emission spectroscopy measurement of Ti and Zr in acidified samples.

  13. Physical and mechanical properties of PMMA bone cement reinforced with nano-sized titania fibers.

    PubMed

    Khaled, S M Z; Charpentier, Paul A; Rizkalla, Amin S

    2011-02-01

    X-ray contrast medium (BaSO(4) or ZrO(2)) used in commercially available PMMA bone cements imparts a detrimental effect on mechanical properties, particularly on flexural strength and fracture toughness. These lower properties facilitate the chance of implant loosening resulting from cement mantle failure. The present study was performed to examine the mechanical properties of a commercially available cement (CMW1) by introducing novel nanostructured titania fibers (n-TiO(2) fibers) into the cement matrix, with the fibers acting as a reinforcing phase. The hydrophilic nature of the n-TiO(2) fibers was modified by using a bifunctional monomer, methacrylic acid. The n-TiO(2) fiber content of the cement was varied from 0 to 2 wt%. Along with the mechanical properties (fracture toughness (K (IC)), flexural strength (FS), and flexural modulus (FM)) of the reinforced cements the following properties were investigated: complex viscosity-versus-time, maximum polymerization temperature (T (max)), dough time (t (dough)), setting time (t (set)), radiopacity, and in vitro biocompatibility. On the basis of the determined mechanical properties, the optimized composition was found at 1 wt% n-TiO(2) fibers, which provided a significant increase in K (IC) (63%), FS (20%), and FM (22%), while retaining the handling properties and in vitro biocompatibility compared to that exhibited by the control cement (CMW1). Moreover, compared to the control cement, there was no significant change in the radiopacity of any of the reinforced cements at p = 0.05. This study demonstrated a novel pathway to augment the mechanical properties of PMMA-based cement by providing an enhanced interfacial interaction and strong adhesion between the functionalized n-TiO( 2) fibers and PMMA matrix, which enhanced the effective load transfer within the cement.

  14. Synthesis and Explosive Consolidation of Titanium, Aluminium, Boron and Carbon Containing Powders

    NASA Astrophysics Data System (ADS)

    Chikhradze, Mikheil; Oniashvili, George; Chikhradze, Nikoloz; D. S Marquis, Fernand

    2016-10-01

    The development of modern technologies in the field of materials science has increased the interest towards the bulk materials with improved physical, chemical and mechanical properties. Composites, fabricated in Ti-Al-B-C systems are characterized by unique physical and mechanical properties. They are attractive for aerospace, power engineering, machine and chemical applications. The technologies to fabricate ultrafine grained powder and bulk materials in Ti-Al-B-C system are described in the paper. It includes results of theoretical and experimental investigation for selection of powders composition and determination of thermodynamic conditions for bland preparation, as well as optimal technological parameters for mechanical alloying and adiabatic compaction. The crystalline coarse Ti, Al, C powders and amorphous B were used as precursors and blends with different compositions of Ti-Al, Ti-Al-C, Ti-B-C and Ti-Al-B were prepared. Preliminary determination/selection of blend compositions was made on the basis of phase diagrams. The powders were mixed according to the selected ratios of components to produce the blend. Blends were processed in “Fritsch” Planetary premium line ball mill for mechanical alloying, syntheses of new phases, amorphization and ultrafine powder production. The blends processing time was variable: 1 to 20 hours. The optimal technological regimes of nano blend preparation were determined experimentally. Ball milled nano blends were placed in metallic tube and loaded by shock waves for realization of consolidation in adiabatic regime. The structure and properties of the obtained ultrafine grained materials depending on the processing parameters are investigated and discussed. For consolidation of the mixture, explosive compaction technology is applied at room temperatures. The prepared mixtures were located in low carbon steel tube and blast energies were used for explosive consolidation compositions. The relationship of ball milling

  15. Readily available titania nanostructuring routines based on mobility and polarity controlled phase separation of an amphiphilic diblock copolymer.

    PubMed

    Hohn, Nuri; Schlosser, Steffen J; Bießmann, Lorenz; Grott, Sebastian; Xia, Senlin; Wang, Kun; Schwartzkopf, Matthias; Roth, Stephan V; Müller-Buschbaum, Peter

    2018-03-15

    The amphiphilic diblock copolymer polystyrene-block-polyethylene oxide is combined with sol-gel chemistry to control the structure formation of blade-coated foam-like titania thin films. The influence of evaporation time before immersion into a poor solvent bath and polarity of the poor solvent bath are studied. Resulting morphological changes are quantified by scanning electron microscopy (SEM) and grazing incidence small angle X-ray scattering (GISAXS) measurements. SEM images surface structures while GISAXS accesses inner film structures. Due to the correlation of evaporation time and mobility of the polymer template during the phase separation process, a decrease in the distances of neighboring titania nanostructures from 50 nm to 22 nm is achieved. Furthermore, through an increase of polarity of an immersion bath the energetic incompatibility of the hydrophobic block and the solvent can be enhanced, leading to an increase of titania nanostructure distances from 35 nm to 55 nm. Thus, a simple approach is presented to control titania nanostructure in foam-like films prepared via blade coating, which enables an easy upscaling of film preparation.

  16. Effect of annealing on the structural and optical properties of TiO2 powder prepared by sol-gel route

    NASA Astrophysics Data System (ADS)

    Halder, Nilanjan; Misra, Kamakhya Prakash

    2016-05-01

    Using titanium isopropoxide as the precursor, Titanium dioxide (TiO2) powder was synthesized via sol-gel method, a promising low temperature route for preparing nanosized metal oxide semiconductors with good homogeneity at low cost. The as-prepared nano powder was thermally treated in air at 550, 650, 750, 900 and 1100°C for 1hr after drying at room temperature and used for further characterization. X-ray diffraction measurements showed that the annealing treatment has a strong impact on the crystal phase of TiO2 samples. The crystallite size as calculated from Debye Scherer formula lies in the range 29-69 nm and is found to increase with increase in annealing temperature. Photoluminescence studies exhibit an improvement in the optical efficiency of the samples with post synthesis heat treatment. Annealing at temperature above 900°C results in a degradation of the structural and optical quality of the TiO2 nano powder samples.

  17. Europium-doped mesoporous titania thin films: rare-earth locations and emission fluctuations under illumination.

    PubMed

    Leroy, Celine Marie; Cardinal, Thierry; Jubera, Veronique; Treguer-Delapierre, Mona; Majimel, Jerome; Manaud, Jean Pierre; Backov, Renal; Boissière, Cedric; Grosso, David; Sanchez, Clement; Viana, Bruno; Pellé, Fabienne

    2008-10-06

    Herein, Eu(III)-doped 3D mesoscopically ordered arrays of mesoporous and nanocrystalline titania are prepared and studied. The rare-earth-doped titania thin films-synthesized via evaporation-induced self-assembly (EISA)-are characterized by using environmental ellipsoporosimetry, electronic microscopy (i.e. high-resolution scanning electron microscopy, HR-SEM, and transmission electron microscopy, HR-TEM), X-ray diffraction, and luminescence spectroscopy. Structural characterizations show that high europium-ion loadings can be incorporated into the titanium-dioxide walls without destroying the mesoporous arrangement. The luminescence properties of Eu(III) are investigated by using steady-state and time-resolved spectroscopy via excitation of the Eu(III) ions through the titania host. Using Eu(III) luminescence as a probe, the europium-ion sites can be addressed with at least two different environments within the mesoporous framework, namely, a nanocrystalline environment and a glasslike one. Emission fluctuations ((5)D(0)-->(7)F(2)) are observed upon continuous UV excitation in the host matrix. These fluctuations are attributed to charge trapping and appear to be strongly dependent on the amount of europium and the level of crystallinity.

  18. Production of fine calcium powders by centrifugal atomization with rotating quench bath

    DOE PAGES

    Tian, Liang; Ames Lab. and Iowa State Univ., Ames, IA; Anderson, Iver; ...

    2016-02-08

    Recently, a novel Al/Ca composite was produced by severe plastic deformation of Al powders and Ca granules for possible use as a high-voltage power transmission conductor. Since the strength of such composites is inversely proportional to the Ca filament size, fine Ca powders (less than ~250 μm) are needed to achieve the desired high strength for the powder metallurgy production of an Al-matrix composite reinforced by nano-scale Ca filaments. However, fine Ca powders are not commercially available. Therefore, we have developed a method to produce fine Ca powders via centrifugal atomization to supply Ca powder for prototype development of Al/Camore » composite conductor. A secondary goal of the project was to demonstrate that Ca powder can be safely prepared, stored, and handled and could potentially be scaled for commercial production. Our results showed that centrifugal atomization can yield as much as 83 vol. % Ca powder particles smaller than 250 μm. The mean particle size sometimes matches, sometimes deviates substantially from the predictions of the Champagne & Anger equation likely due to unexpected secondary atomization. The particle size distribution is typical for a ligament-disintegration atomization mode. Scanning electron micrographs showed that the morphology of these Ca powders varied with powder size. Spark testing and auto-ignition tests indicated that the atomized powders were difficult to ignite, providing confidence that this material can be handled safely in air.« less

  19. Impedance and modulus spectroscopic study of nano hydroxyapatite

    NASA Astrophysics Data System (ADS)

    Jogiya, B. V.; Jethava, H. O.; Tank, K. P.; Raviya, V. R.; Joshi, M. J.

    2016-05-01

    Hydroxyapatite (Ca10 (PO4)6 (OH)2, HAP) is the main inorganic component of the hard tissues in bones and also important material for orthopedic and dental implant applications. Nano HAP is of great interest due to its various bio-medical applications. In the present work the nano HAP was synthesized by using surfactant mediated approach. Structure and morphology of the synthesized nano HAP was examined by the Powder XRD and TEM. Impedance study was carried out on pelletized sample in a frequency range of 100Hz to 20MHz at room temperature. The variation of dielectric constant, dielectric loss, and a.c. conductivity with frequency of applied field was studied. The Nyquist plot as well as modulus plot was drawn. The Nyquist plot showed two semicircle arcs, which indicated the presence of grain and grain boundary effect in the sample. The typical behavior of the Nyquist plot was represented by equivalent circuit having two parallel RC combinations in series.

  20. Impact of nano and bulk ZrO2, TiO2 particles on soil nutrient contents and PGPR.

    PubMed

    Karunakaran, Gopalu; Suriyaprabha, Rangaraj; Manivasakan, Palanisamy; Yuvakkumar, Rathinam; Rajendran, Venkatachalam; Kannan, Narayanasamy

    2013-01-01

    Currently, nanometal oxides are used extensively in different industries such as medicine, cosmetics and food. The increased consumption of nanoparticles (NPs) leads the necessity to understand the fate of the nanoparticles in the environment. The present study focused on the ecotoxicological behaviour of bulk and nano ZrO2 (Zirconia) and TiO2 (Titania) particles on PGPR (plant growth promoting rhizobacteria), soil and its nutrient contents. The microbial susceptibility study showed that nano TiO2 had 13 +/- 0.9 mm (B. megaterium), 15 +/- 0.2 mm (P. fluorescens), 16 +/- 0.2 mm (A. vinelandii) and 12 +/- 0.3 mm (B. brevis) zones of inhibition. However, nano and bulk ZrO2 particles were non-toxic to PGPR. In addition, it was found that toxicity varied depends on the medium of reaction. The soil study showed that nano TiO2 was found to be highly toxic, whereas bulk TiO2 was less toxic towards soil bacterial populations at 1000 mg L(-1). In contrast, nano and bulk ZrO2 were found to be inert at 1000 mg L(-1). The observed zeta potential and hydrophobicity of TiO2 particles causes more toxic than ZrO2 in parallel with particle size. However, nano TiO2 decreases the microbial population as well as nutrient level of the soil but not zirconia. Our finding shows that the mechanism of toxicity depends on size, hydrophobic potential and zeta potential of the metal oxide particles. Thus, it is necessary to take safety measures during the disposal and use of such toxic nanoparticles in the soil to prevent their hazardous effects.

  1. Tris(hydroxymethyl)aminomethane photooxidation on titania based photoanodes and its implication for photoelectrochemical biofuel cells

    NASA Astrophysics Data System (ADS)

    Filipiak, Marcin S.; Zloczewska, Adrianna; Grzeskowiak, Piotr; Lynch, Robert; Jönsson-Niedziolka, Martin

    2015-09-01

    In many photoelectrochemical biofuel cells tris(hydroxymethyl)aminomethane (TRIS) is used a buffer. We show that TRIS can be readily photooxidised on titania electrodes. Combining a titania nanotube photoanode in a TRIS buffer with an air-breathing enzymatic biocathode we construct a relatively efficient photoelectrochemical biofuel cell using the TRIS buffer as fuel. This shows both the prospect of using air-breathing bio-cathodes in this kind of cells, but more importantly, shows the need for caution when using TRIS as buffer in photoelectrochemical applications.

  2. Synthesis of Nano-Scale Fast Ion Conducting Cubic Li7La3Zr2O12

    DTIC Science & Technology

    2013-09-25

    offer the flexibility to make nano-dimensional particles with high sinterability nor the ability to coat/protect electrode powders. By developing a...sintering temperature are needed. One possible approach is to use small particles , such as nano-scale particles , that can be sintered at lower temperatures...matrix to suppress Li dendrite penetration. By developing a sol–gel process, the LLZO particle size can be precisely tuned, from the nanometer to the

  3. Soft template strategy to synthesize iron oxide-titania yolk-shell nanoparticles as high-performance anode materials for lithium-ion battery applications.

    PubMed

    Lim, Joohyun; Um, Ji Hyun; Ahn, Jihoon; Yu, Seung-Ho; Sung, Yung-Eun; Lee, Jin-Kyu

    2015-05-18

    Yolk-shell-structured nanoparticles with iron oxide core, void, and a titania shell configuration are prepared by a simple soft template method and used as the anode material for lithium ion batteries. The iron oxide-titania yolk-shell nanoparticles (IO@void@TNPs) exhibit a higher and more stable capacity than simply mixed nanoparticles of iron oxide and hollow titania because of the unique structure obtained by the perfect separation between iron oxide nanoparticles, in combination with the adequate internal void space provided by stable titania shells. Moreover, the structural effect of IO@void@TNPs clearly demonstrates that the capacity retention value after 50 cycles is approximately 4 times that for IONPs under harsh operating conditions, that is, when the temperature is increased to 80 °C. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Ultrasound enhanced release of therapeutics from drug-releasing implants based on titania nanotube arrays.

    PubMed

    Aw, Moom Sinn; Losic, Dusan

    2013-02-25

    A non-invasive and external stimulus-driven local drug delivery system (DDS) based on titania nanotube (TNT) arrays loaded with drug encapsulated polymeric micelles as drug carriers and ultrasound generator is described. Ultrasound waves (USW) generated by a pulsating sonication probe (Sonotrode) in phosphate buffered saline (PBS) at pH 7.2 as the medium for transmitting pressure waves, were used to release drug-loaded nano-carriers from the TNT arrays. It was demonstrated that a very rapid release in pulsatile mode can be achieved, controlled by several parameters on the ultrasonic generator. This includes pulse length, time, amplitude and power intensity. By optimization of these parameters, an immediate drug-micelles release of 100% that spans a desirable time of 5-50 min was achieved. It was shown that stimulated release can be generated and reproduced at any time throughout the TNT-Ti implant life, suggesting considerable potential of this approach as a feasible and tunable ultrasound-mediated drug delivery system in situ via drug-releasing implants. It is expected that this concept can be translated from an in vitro to in vivo regime for therapeutic applications using drug-releasing implants in orthopedic and coronary stents. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

  5. Linking the Physicochemical Properities of Titania with Its Biocidal Properities

    EPA Science Inventory

    LINKING THE PHYSICOCHEMICAL PROPERTIES OF TITANIA WITH ITS BIOCIDAL PROPERTIES. C. Han1, L. Putvin2, M. Pelaez1, H. Zamankhan3, H. Choi3, D. Betancourt4a, D. Dionysiou1. B. Veronesi4b, 1 Department of Biomedical, Chemical and Environmental Engineering, University of Cincinnati...

  6. Engineering titania nanostructure to tune and improve its photocatalytic activity

    PubMed Central

    Cargnello, Matteo; Montini, Tiziano; Smolin, Sergey Y.; Priebe, Jacqueline B.; Delgado Jaén, Juan J.; Doan-Nguyen, Vicky V. T.; McKay, Ian S.; Schwalbe, Jay A.; Pohl, Marga-Martina; Gordon, Thomas R.; Lu, Yupeng; Baxter, Jason B.; Brückner, Angelika; Murray, Christopher B.

    2016-01-01

    Photocatalytic pathways could prove crucial to the sustainable production of fuels and chemicals required for a carbon-neutral society. Electron−hole recombination is a critical problem that has, so far, limited the efficiency of the most promising photocatalytic materials. Here, we show the efficacy of anisotropy in improving charge separation and thereby boosting the activity of a titania (TiO2) photocatalytic system. Specifically, we show that H2 production in uniform, one-dimensional brookite titania nanorods is highly enhanced by engineering their length. By using complimentary characterization techniques to separately probe excited electrons and holes, we link the high observed reaction rates to the anisotropic structure, which favors efficient carrier utilization. Quantum yield values for hydrogen production from ethanol, glycerol, and glucose as high as 65%, 35%, and 6%, respectively, demonstrate the promise and generality of this approach for improving the photoactivity of semiconducting nanostructures for a wide range of reacting systems. PMID:27035977

  7. Effect of annealing on the structural and optical properties of TiO{sub 2} powder prepared by sol-gel route

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Halder, Nilanjan; Misra, Kamakhya Prakash

    2016-05-06

    Using titanium isopropoxide as the precursor, Titanium dioxide (TiO{sub 2}) powder was synthesized via sol-gel method, a promising low temperature route for preparing nanosized metal oxide semiconductors with good homogeneity at low cost. The as-prepared nano powder was thermally treated in air at 550, 650, 750, 900 and 1100°C for 1hr after drying at room temperature and used for further characterization. X-ray diffraction measurements showed that the annealing treatment has a strong impact on the crystal phase of TiO{sub 2} samples. The crystallite size as calculated from Debye Scherer formula lies in the range 29-69 nm and is found to increasemore » with increase in annealing temperature. Photoluminescence studies exhibit an improvement in the optical efficiency of the samples with post synthesis heat treatment. Annealing at temperature above 900°C results in a degradation of the structural and optical quality of the TiO{sub 2} nano powder samples.« less

  8. Selective Laser Sintering of Nano Al2O3 Infused Polyamide

    PubMed Central

    Warnakula, Anthony; Singamneni, Sarat

    2017-01-01

    Nano Al2O3 polyamide composites are evaluated for processing by selective laser sintering. A thermal characterization of the polymer composite powders allowed us to establish the possible initial settings. Initial experiments are conducted to identify the most suitable combinations of process parameters. Based on the results of the initial trials, more promising ranges of different process parameters could be identified. The post sintering characterization showed evidence of sufficient inter-particle sintering and intra-layer coalescence. While the inter-particle coalescence gradually improved, the porosity levels slightly decreased with increasing laser power. The nano-filler particles tend to agglomerate around the beads along the solid tracks, possibly due to Van der Walls forces. The tensile stress results showed an almost linear increase with increasing nano-filler content. PMID:28773220

  9. Analysis of protein phosphorylation by monolithic extraction columns based on poly(divinylbenzene) containing embedded titanium dioxide and zirconium dioxide nano-powders.

    PubMed

    Rainer, Matthias; Sonderegger, Harald; Bakry, Rania; Huck, Christian W; Morandell, Sandra; Huber, Lukas A; Gjerde, Douglas T; Bonn, Günther K

    2008-11-01

    The potential of an organic monolith with incorporated titanium dioxide (TiO(2)) and zirconium dioxide (ZrO(2)) nanoparticles was evaluated for the selective enrichment of phosphorylated peptides from tryptic digests. A pipette tip was fitted with a monolith based on divinylbenzene (DVB) of highly porous structure, which allows sample to pass through the monolithic bed. The enrichment of phosphopeptides was enhanced by increasing the pipetting cycles during the sample preparation and a higher recovery could be achieved with adequate buffer systems. A complete automated process was developed for enrichment of phosphopeptides leading to high reproducibility and resulting in a robust method designed to minimize analytical variance while providing high sensitivity at high sample throughput. The effect of particle size on the selectivity of phosphopeptides was investigated by comparative studies with nano- and microscale TiO(2) and ZrO(2) powders. Eleven phosphopeptides from alpha-casein digest could be recovered by an optimized mixture of microscale TiO(2)/ZrO(2) particles, whereas nine additional phosphopeptides could be retained by the same mixture of nano-structured material. When compared to conventional immobilized metal-ion affinity chromatography and commercial phosphorylation-enrichment kits, higher selectivity was observed in case of self fabricated tips. About 20 phosphopeptides could be retained from alpha-casein and five from beta-casein digests by using TiO(2) and ZrO(2) based extraction tips. Further selectivity for phosphopeptides was demonstrated by enriching a digest of in vitro phosphorylated extracellular signal regulated kinase 1 (ERK1). Two phosphorylated peptides of ERK1 could be identified by MALDI-MS/MS measurements and a following MASCOT database search.

  10. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Paul, Nibedita; Deka, Amrita; Mohanta, Dambarudhar, E-mail: best@tezu.ernet.in

    The present work reports on the effect of Tb³⁺ doping on the luminescence and photocatalytic performance of nano-structured titania derived through a sol-gel route. X-ray diffraction patterns have revealed the existence of anatase phase with and without Tb³⁺ doping and with an improved orientation factor along (004) and (200) planes. Transmission electron microscopy and selective area electron diffraction studies, while exhibiting ample poly-crystallinity feature, have predicted an average particle size of ~9 nm and ~6 nm for the un-doped and 5% Tb³⁺ doped nano-titania samples; respectively. Apart from emissions accompanied by different types of defects, Tb³⁺ related transitions, such as,more » ⁵D₃ → ⁷F₅, ⁵D₃ → ⁷F₄, and ⁵D₄ → ⁷F₆ were identified in the photoluminescence spectra. Brunauer-Emmett-Teller surface area analysis, as carried out on a Tb³⁺ doped nano-titania system, has demonstrated a more-open hysteretic loop owing to significant difference of N₂ adsorption/desorption rates. The photocatalytic activity of nano-titania, as evaluated from the nature of degradation of methyl orange under UV illumination, exhibited the highest efficiency for a Tb³⁺ doping level of 2.5%. The augmented photocatalytic degradation has also been discussed in the light of a model based on pseudo first-order kinetics.« less

  11. Silica sacrificial layer-assisted in-plane incorporation of Au nanoparticles into mesoporous titania thin films through different reduction methods.

    PubMed

    Liang, Chih-Peng; Yamauchi, Yusuke; Liu, Chia-Hung; Wu, Kevin C-W

    2013-06-28

    This study focuses on the incorporation of gold nanoparticles (Au NPs) into our previously synthesized mesoporous titania thin films consisting of titania nanopillars and inverse mesospace (C. W. Wu, T. Ohsuna, M. Kuwabara and K. Kuroda, J. Am. Chem. Soc., 2006, 128, 4544-4545, denoted as MTTFs). Recently, mesoporous titania materials doped with noble metals such as gold have attracted considerable attention because noble metals can enhance the efficiency of mesoporous titania-based devices. In this research, we attempted to use four different reduction methods (i.e., thermal treatment, photo irradiation, liquid immersion, and vapor contacting) to introduce gold nanoparticles (Au NPs) into MTTFs. The synthesized Au@MTTFs were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). We further systematically investigated the formation mechanism of gold nanoparticles on the external and internal surfaces of the MTTFs. With the assistance of a silica sacrificial layer, well-dispersed Au NPs with sizes of 4.1 nm were obtained inside the MTTF by photo irradiation. The synthesized Au@MTTF materials show great potential in various photo-electronic and photo-catalytic applications.

  12. Nanoparticles by spray drying using innovative new technology: the Büchi nano spray dryer B-90.

    PubMed

    Li, Xiang; Anton, Nicolas; Arpagaus, Cordin; Belleteix, Fabrice; Vandamme, Thierry F

    2010-10-15

    Spray drying technology is widely known and used to transform liquids (solutions, emulsions, suspension, slurries, pastes or even melts) into solid powders. Its main applications are found in the food, chemical and materials industries to enhance ingredient conservation, particle properties, powder handling and storage etc. However, spray drying can also be used for specific applications in the formulation of pharmaceuticals for drug delivery (e.g. particles for pulmonary delivery). Büchi is a reference in the development of spray drying technology, notably for laboratory scale devices. This study presents the Nano Spray Dryer B-90, a revolutionary new sprayer developed by Büchi, use of which can lower the size of the produced dried particles by an order of magnitude attaining submicron sizes. In this paper, results are presented with a panel of five representative polymeric wall materials (arabic gum, whey protein, polyvinyl alcohol, modified starch, and maltodextrin) and the potentials to encapsulate nano-emulsions, or to formulate nano-crystals (e.g. from furosemide) are also shown. Copyright © 2010 Elsevier B.V. All rights reserved.

  13. Cell Attachment and Proliferation of Human Adipose-Derived Stem Cells on PLGA/Chitosan Electrospun Nano-Biocomposite.

    PubMed

    Razavi, Shahnaz; Karbasi, Saeed; Morshed, Mohammad; Zarkesh Esfahani, Hamid; Golozar, Mohammad; Vaezifar, Sedigheh

    2015-01-01

    In this study, nano-biocomposite composed of poly (lactide-co-glycolide) (PLGA) and chitosan (CS) were electrospun through a single nozzle by dispersing the CS nano-powders in PLGA solution. The cellular behavior of human adipose derived stem cells (h-ADSCs) on random and aligned scaffolds was then evaluated. In this experimental study, the PLGA/CS scaffolds were prepared at the different ratios of 90/10, 80/20, and 70/30 (w/w) %. Morphology, cell adhesion and prolif- eration rate of h-ADSCs on the scaffolds were assessed using scanning electron microscope (SEM), 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay and trypan blue staining respectively. H-ADSCs seeded on the matrices indicated that the PLGA/CS composite matrix with aligned nanofibres and higher content of CS nano-powders gave significantly better performance than others in terms of cell adhesion and proliferation rate (P<0.05). We found that CS enhanced cell adhesion and proliferation rate, and aligned nanofibers guided cell growth along the longitudinal axis of the nanofibers, which would provide a beneficial approach for tissue engineering.

  14. Co-electrospun lead selenide/titania-core/sheath nanowires for photovoltaic applications.

    DOT National Transportation Integrated Search

    2012-12-01

    This study presents a novel, low-cost, all-inorganic lead selenide-titania (PbSe/TiO2) nanowire : heterostructure material synthesis for photovoltaic applications. PbSe nanorods (NRs) have been coelectrospun : within a TiO2 nanotube with high connect...

  15. Preparation and characterisation of titania/hydroxyapatite composite coatings obtained by sol-gel process.

    PubMed

    Milella, E; Cosentino, F; Licciulli, A; Massaro, C

    2001-06-01

    In the present work a titania network encapsulating a hydroxyapatite particulate phase is proposed as a bioceramic composite coating. The coating on a titanium substrate was produced starting from a sol containing a mixture of titania colloidal particles and hydroxyapatite submicron particles using the dip-coating technique. The microstructure, the morphology and the surface chemical composition of the coating were characterised using X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. Adhesion tests were also performed. These analyses showed that the obtained coating was chemically clean, homogeneous, rough, porous, with a low thickness and well-defined phase composition as well as a good adhesion to the substrate.

  16. Synthesis and characterization of Al & SiCp nano particles by non-contact ultrasonic assisted method

    NASA Astrophysics Data System (ADS)

    Swain, Pradyut Kumar; Das, Ratnakar; Sahoo, Ashok Kumar; Naik, Bikash; Padhi, Payodhar

    2018-05-01

    The present study deals with proper mixing of SiCp nano particle in the aluminum metal matrix in two stages of processing i.e. primary and secondary. During primary processing, the breaking of agglomeration of nano particles take place and these are mixed with liquid aluminum powder using high frequency(35kHz) mechanical vibration. But, during secondary processing, mixing of nano particles along with subsequent cooling take place using high frequency non contact ultrasonic method. The study also reveals that in the liquid metal nano particle were uniformly dispersed and the segregation of the particles near the grain boundaries is due to pushing of the nano particle during grain growth. The study was performed by taking aluminum as matrix and SiCp as reinforcement with weight fraction of 2% and 3% and SiCp particles sizes of 30nm each. Scanning electron microscopy(SEM) and X-ray diffraction(XRD) were conducted for characterization of nano composite material.

  17. DEXTRON TEMPLATED MICROWAVE-ASSISTED SYNTHESIS OF POROUS TITANIUM DIOXIDE

    EPA Science Inventory

    An alternative route to the preparation and formation of porous titania powders and carbon coated titania using microwave radiation is described. Inexpensive dextrose was chosen as capping agent or template in view of its high water solubility when compared to other sugar templat...

  18. Development of anodic titania nanotubes for application in high sensitivity amperometric glucose and uric acid biosensors.

    PubMed

    Lee, Hsiang-Ching; Zhang, Li-Fan; Lin, Jyh-Ling; Chin, Yuan-Lung; Sun, Tai-Ping

    2013-10-21

    The purpose of this study was to develop novel nanoscale biosensors using titania nanotubes (TNTs) made by anodization. Titania nanotubes were produced on pure titanium sheets by anodization at room temperature. In this research, the electrolyte composition ethylene glycol 250 mL/NH4F 1.5 g/DI water 20 mL was found to produce the best titania nanotubes array films for application in amperometric biosensors. The amperometric results exhibit an excellent linearity for uric acid (UA) concentrations in the range between 2 and 14 mg/dL, with 23.3 (µA·cm-2)·(mg/dL)-1 UA sensitivity, and a correlation coefficient of 0.993. The glucose biosensor presented a good linear relationship in the lower glucose concentration range between 50 and 125 mg/dL, and the corresponding sensitivity was approximately 249.6 (µA·cm-2)·(100 mg/dL)-1 glucose, with a correlation coefficient of 0.973.

  19. Development of Anodic Titania Nanotubes for Application in High Sensitivity Amperometric Glucose and Uric Acid Biosensors

    PubMed Central

    Lee, Hsiang-Ching; Zhang, Li-Fan; Lin, Jyh-Ling; Chin, Yuan-Lung; Sun, Tai-Ping

    2013-01-01

    The purpose of this study was to develop novel nanoscale biosensors using titania nanotubes (TNTs) made by anodization. Titania nanotubes were produced on pure titanium sheets by anodization at room temperature. In this research, the electrolyte composition ethylene glycol 250 mL/NH4F 1.5 g/DI water 20 mL was found to produce the best titania nanotubes array films for application in amperometric biosensors. The amperometric results exhibit an excellent linearity for uric acid (UA) concentrations in the range between 2 and 14 mg/dL, with 23.3 (μA·cm−2)·(mg/dL)−1 UA sensitivity, and a correlation coefficient of 0.993. The glucose biosensor presented a good linear relationship in the lower glucose concentration range between 50 and 125 mg/dL, and the corresponding sensitivity was approximately 249.6 (μA·cm−2)·(100 mg/dL)−1 glucose, with a correlation coefficient of 0.973. PMID:24152934

  20. Microstructural evolutions and stress studies of titania films derived by "spin-deposition" methods

    NASA Astrophysics Data System (ADS)

    Eun, Tai Hee

    Titania (TiO2) films were fabricated by a "spin-deposition" process. Titanium alkoxides react with moisture in the air, leading to the formation of metal hydroxides which subsequently form an oxide network during deposition. The microstructure of film is easily controlled by the selection of titanium alkoxides and solvents. Films from titanium n-butoxide (Ti(OC 4H9n)4) in toluene exhibited a dense microstructure devoid of cracks. In contrast, films produced from titanium isopropoxide (Ti(OC3H7i)4) in the toluene regularly contained micro-cracks. Titanium isopropoxide in either isopropanol or n-propanol produces highly porous films. After annealing at 300°C, the film derived from titanium n-butoxide in toluene possessed 2˜3 nm nanocrystallites of titanium monoxide (TiO, cubic) in amorphous matrices. TEM and FTIR investigations indicate that the intermediates formed from the oligomers of titanium n-butoxide lead to the formation of the TiO. By annealing at 400°C, the TiO nanoparticles transformed to the TiO2 (anatase). At annealing higher than 450°C, the film was completely crystallized into a polycrystalline of ˜5 nm anatase. In water-rich environments, all amorphous titania films crystallized within 24 hours at 100°C. The crystallization of films is confirmed by XRD and FTIR studies. Amorphous titania films have remnant bridging and terminal hydroxy groups. Removal of these hydroxy groups is promoted by water vapor, which induces the crystallization of amorphous titania to anatase. The mechanism of crystallization in a water-rich environment was proposed based on the FTIR study. Stress evolution in titania films spin-deposited on silicon with solutions of titanium n-butoxide in toluene was investigated by an in-situ wafer curvature method. Tensile stresses were induced due to the densification by removal of water molecules attached to Ti-O-Ti linkages from 200°C to 300°C. The effect of crystallization on stress in the film was studied by comparing results

  1. Effects of Structural Properties of Electrospun TiO2 Nano-fiber Meshes on their Osteogenic Potential

    PubMed Central

    Wang, Xiaokun; Gittens, Rolando A.; Song, Rosemary; Tannenbaum, Rina; Olivares-Navarrete, Rene; Schwartz, Zvi; Chen, Haifeng; Boyan, Barbara D.

    2011-01-01

    Ideal outcomes in the field of tissue engineering and regenerative medicine involve biomaterials that can enhance cell differentiation and production of local factors for natural tissue regeneration without the use of systemic drugs. Biomaterials typically used in tissue engineering applications include polymeric scaffolds that mimic the 3-D structural environment of the native tissue, but these are often functionalized with proteins or small peptides to improve their biological performance. For bone applications, titanium (Ti) implants, or more appropriately the titania (TiO2) passive oxide layer formed on their surface, have been shown to enhance osteoblast differentiation in vitro and to promote osseointegration in vivo. In this study we evaluated the effect on osteoblast differentiation of pure TiO2 nano-fiber meshes with different surface micro-roughness and nano-fiber diameters, prepared by the electrospinning method. MG63 cells were seeded on TiO2 meshes, and cell number, differentiation markers and local factor production were analyzed. The results showed that cells grew throughout the entire surfaces and with similar morphology in all groups. Cell number was sensitive to surface micro-roughness, whereas cell differentiation and local factor production was regulated by both surface roughness and nano-fiber diameter. These results indicate that scaffold structural cues alone can be used to drive cell differentiation and create an osteogenic environment without the use of exogenous factors. PMID:22075122

  2. Effects of Ambient High Temperature Exposure on Alumina-Titania High Emittance Surfaces for Solar Dynamic Systems

    NASA Technical Reports Server (NTRS)

    deGroh, Kim K.; Smith, Daniela C.; Wheeler, Donald R.; MacLachlam, Brian J.

    1998-01-01

    Solar dynamic (SD) space power systems require durable, high emittance surfaces on a number of critical components, such as heat receiver interior surfaces and parasitic load radiator (PLR) elements. To enhance surface characteristics, an alumina-titania coating has been applied to 500 heat receiver thermal energy containment canisters and the PLR of NASA Lewis Research Center's (LeRC) 2 kW SD ground test demonstrator (GTD). The alumina-titania coating was chosen because it had been found to maintain its high emittance under vacuum (less than or equal to 10(exp -6) torr) at high temperatures (1457 F (827 C)) for an extended period (approximately 2,700 hours). However, preflight verification of SD systems components, such as the PLR require operation at ambient pressure and high temperatures. Therefore, the purpose of this research was to evaluate the durability of the alumina-titania coating at high temperature in air. Fifteen of sixteen alumina-titania coated Incoloy samples were exposed to high temperatures (600 F (316 C) to l500 F (816 C)) for various durations (2 to 32 hours). Samples, were characterized prior to and after heat treatment for reflectance, solar absorptance, room temperature emittance and emittance at 1,200 F (649 C). Samples were also examined to detect physical defects and to determine surface chemistry using optical microscopy, scanning electron microscopy operated with an energy dispersive spectroscopy (EDS) system, and x ray photoelectron spectroscopy (XPS). Visual examination of the heat-treated samples showed a whitening of samples exposed to temperatures of 1,000 F (538 C) and above. Correspondingly, the optical properties of these samples had degraded. A sample exposed to 1,500 F (816 C) for 24 hours had whitened and the thermal emittance at 1,200 F (649 C) had decreased from the non-heat treated value of 0.94 to 0.62. The coating on this sample had become embrittled with spalling off the substrate noticeable at several locations. Based

  3. Photo-catalytic decolourisation of toxic dye with N-doped titania: a case study with Acid Blue 25.

    PubMed

    Chakrabortty, Dhruba; Gupta, Susmita Sen

    2013-05-01

    Dyes are one of the hazardous water pollutants. Toxic Acid Blue 25, an anthraquinonic dye, has been decolourised by photo-catalysing it with nitrogen doped titania in aqueous medium. The photo catalyst was prepared from 15% TiCl3 and 25% aqueous NH3 solution as precursor. XRD and TEM revealed the formation of well crystalline anatase phase having particle size in the nano-range. BET surface area of the sample was higher than that of pure anatase TiO2. DRS showed higher absorption of radiation in visible range compared to pure anatase TiO2. XPS revealed the presence of nitrogen in N-Ti-O environment. The experimental parameters, namely, photocatalyst dose, initial dye concentration as well as solution pH influence the decolourisation process. At pH 3.0, the N-TiO2 could decolourise almost 100% Acid Blue 25 within one hour. The influence of N-TiO2 dose, initial concentration of Acid Blue 25 and solution pH on adsorption-desorption equilibrium is also studied. The adsorption process follows Lagergren first order kinetics while the modified Langmuir-Hinselwood model is suitably fitted for photocatalytic decolourisation of Acid Blue 25.

  4. The Effect of Sulphate Anions on the Ultrafine Titania Nucleation

    NASA Astrophysics Data System (ADS)

    Kotsyubynsky, Volodymyr O.; Myronyuk, Ivan F.; Chelyadyn, Volodymyr L.; Hrubiak, Andriy B.; Moklyak, Volodymyr V.; Fedorchenko, Sofia V.

    2017-05-01

    The phenomenological model of sulphate anions effect on the nanodispersed titania synthesis during hydrolysis of titanium tetrachloride was studied. It was proposed that both chelating and bridging bidentate complexes formation between sulphate anions and octahedrally coordinated [Ti(OH)h(OH2)6-h](4-h)+ mononers is the determinative factor for anatase phase nucleation.

  5. Self-assembly of protein-based biomaterials initiated by titania nanotubes.

    PubMed

    Forstater, Jacob H; Kleinhammes, Alfred; Wu, Yue

    2013-12-03

    Protein-based biomaterials are a promising strategy for creating robust highly selective biocatalysts. The assembled biomaterials must sufficiently retain the near-native structure of proteins and provide molecular access to catalytically active sites. These requirements often exclude the use of conventional assembly techniques, which rely on covalent cross-linking of proteins or entrapment within a scaffold. Here we demonstrate that titania nanotubes can initiate and template the self-assembly of enzymes, such as ribonuclease A, while maintaining their catalytic activity. Initially, the enzymes form multilayer thick ellipsoidal aggregates centered on the nanotube surface; subsequently, these nanosized entities assemble into a micrometer-sized enzyme material that has enhanced enzymatic activity and contains as little as 0.1 wt % TiO2 nanotubes. This phenomenon is uniquely associated with the active anatase (001)-like surface of titania nanotubes and does not occur on other anatase nanomaterials, which contain significantly fewer undercoordinated Ti surface sites. These findings present a nanotechnology-enabled mechanism of biomaterial growth and open a new route for creating stable protein-based biomaterials and biocatalysts without the need for chemical modification.

  6. Double-sided anodic titania nanotube arrays: a lopsided growth process.

    PubMed

    Sun, Lidong; Zhang, Sam; Sun, Xiao Wei; Wang, Xiaoyan; Cai, Yanli

    2010-12-07

    In the past decade, the pore diameter of anodic titania nanotubes was reported to be influenced by a number of factors in organic electrolyte, for example, applied potential, working distance, water content, and temperature. All these were closely related to potential drop in the organic electrolyte. In this work, the essential role of electric field originating from the potential drop was directly revealed for the first time using a simple two-electrode anodizing method. Anodic titania nanotube arrays were grown simultaneously at both sides of a titanium foil, with tube length being longer at the front side than that at the back side. This lopsided growth was attributed to the higher ionic flux induced by electric field at the front side. Accordingly, the nanotube length was further tailored to be comparable at both sides by modulating the electric field. These results are promising to be used in parallel configuration dye-sensitized solar cells, water splitting, and gas sensors, as a result of high surface area produced by the double-sided architecture.

  7. Synthesis and characterization of scandia ceria stabilized zirconia powders prepared by polymeric precursor method for integration into anode-supported solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Tu, Hengyong; Liu, Xin; Yu, Qingchun

    2011-03-01

    Scandia ceria stabilized zirconia (10Sc1CeSZ) powders are synthesized by polymeric precursor method for use as the electrolyte of anode-supported solid oxide fuel cell (SOFC). The synthesized powders are characterized in terms of crystalline structure, particle shape and size distribution by X-ray diffraction (XRD), transmission electron microscopy (TEM) and photon correlation spectroscopy (PCS). 10Sc1CeSZ electrolyte films are deposited on green anode substrate by screen-printing method. Effects of 10Sc1CeSZ powder characteristics on sintered films are investigated regarding the integration process for application as the electrolytes in anode-supported SOFCs. It is found that the 10Sc1CeSZ films made from nano-sized powders with average size of 655 nm are very porous with many open pores. In comparison, the 10Sc1CeSZ films made from micron-sized powders with average size of 2.5 μm, which are obtained by calcination of nano-sized powders at higher temperatures, are much denser with a few closed pinholes. The cell performances are 911 mW cm-2 at the current density of 1.25 A cm-2 and 800 °C by application of Ce0.8Gd0.2O2 (CGO) barrier layer and La0.6Sr0.4CoO3 (LSC) cathode.

  8. Reduction mechanism of surface oxide films and characterization of formations on pulse electric-current sintered Al Mg alloy powders

    NASA Astrophysics Data System (ADS)

    Xie, Guoqiang; Ohashi, Osamu; Song, Minghui; Mitsuishi, Kazutaka; Furuya, Kazuo

    2005-02-01

    The microstructure of interfaces between powder particles in Al-Mg alloy specimens sintered by pulse electric-current sintering (PECS) process was characterized using high resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray spectroscopy (EDS). The crystalline precipitates with nano-size in the interface were observed in all of Al-Mg alloy specimens. The composition was determined to be MgAl 2O 4 or MgO, or both of them, which depended on Mg content in alloy powder and sintering temperature. The precipitates were suggested to contribute to reduction reaction of Mg with oxide films originally covered at powder particles surface.

  9. Titania nanotubes with adjustable dimensions for drug reservoir sites and enhanced cell adhesion.

    PubMed

    Çalışkan, Nazlı; Bayram, Cem; Erdal, Ebru; Karahaliloğlu, Zeynep; Denkbaş, Emir Baki

    2014-02-01

    This study aims to generate a bactericidal agent releasing surface via nanotube layer on titanium metal and to investigate how aspect ratio of nanotubes affects drug elution time and cell proliferation. Titania nanotube layers were generated on metal surfaces by anodic oxidation at various voltage and time parameters. Gentamicin loading was carried out via simple pipetting and the samples were tested against S. aureus for the efficacy of the applied modification. Drug releasing time and cell proliferation were also tested in vitro. Titania nanotube layers with varying diameters and lengths were prepared after anodization and anodizing duration was found as the most effective parameter for amount of loaded drug and drug releasing time. Drug elution lasted up to 4 days after anodizing for 80 min of the samples, whereas release completed in 24 h when the samples were anodized for 20 min. All processed samples had bactericidal properties against S. aureus organism except unmodified titanium, which was also subjected to drug incorporation step. The anodization also enhanced water wettability and cell adhesion results. Anodic oxidation is an effective surface modification to enhance tissue-implant interactions and also resultant titania layer can act as a drug reservoir for the release of bactericidal agents. The use of implants as local drug eluting devices is promising but further in vivo testing is required. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Au-coated 3-D nanoporous titania layer prepared using polystyrene-b-poly(2-vinylpyridine) block copolymer nanoparticles.

    PubMed

    Shin, Won-Jeong; Basarir, Fevzihan; Yoon, Tae-Ho; Lee, Jae-Suk

    2009-04-09

    New nanoporous structures of Au-coated titania layers were prepared by using amphiphilic block copolymer nanoparticles as a template. A 3-D template composed of self-assembled quaternized polystyrene-b-poly(2-vinylpyridine) (Q-PS-b-P2VP) block copolymer nanoparticles below 100 nm was prepared. The core-shell-type nanoparticles were well ordered three-dimensionally using the vertical immersion method on the substrate. The polar solvents were added to the polymer solution to prevent particle merging at 40 degrees C when considering the interaction between polymer nanoparticles and solvents. Furthermore, Au-coated PS-b-P2VP nanoparticles were prepared using thiol-capped Au nanoparticles (3 nm). The 3-D arrays with Au-coated PS-b-P2VP nanoparticles as a template contributed to the preparation of the nanoporous Au-coated titania layer. Therefore, the nanoporous Au-coated titania layer was fabricated by removing PS-b-P2VP block copolymer nanoparticles by oxygen plasma etching.

  11. Sol-gel titania-coated needles for solid phase dynamic extraction-GC/MS analysis of desomorphine and desocodeine.

    PubMed

    Su, Chi-Ju; Srimurugan, Sankarewaran; Chen, Chinpiao; Shu, Hun-Chi

    2011-01-01

    Novel sol-gel titania film coated needles for solid-phase dynamic extraction (SPDE)-GC/MS analysis of desomorphine and desocodeine are described. The high thermal stability of titania film permits efficient extraction and analysis of poorly volatile opiate drugs. The influences of sol-gel reaction time, coating layer, extraction and desorption time and temperature on the SPDE needle performance were investigated. The deuterium labeled internal standard was introduced either during the extraction of analyte or directly injected to GC after the extraction process. The latter method was shown to be more sensitive for the analysis of water and urine samples containing opiate drugs. The proposed conditions provided a wide linear range (from 5-5000 ppb), and satisfactory linearity, with R(2) values from 0.9958 to 0.9999, and prominent sensitivity, LOQs (1.0-5.0 ng/g). The sol-gel titania film coated needle with SPDE-GC/MS will be a promising technique for desomorphine and desocodeine analysis in urine.

  12. Synthesis and luminescence properties of hybrid organic-inorganic transparent titania thin film activated by in- situ formed lanthanide complexes

    NASA Astrophysics Data System (ADS)

    Wang, Yige; Wang, Li; Li, Huanrong; Liu, Peng; Qin, Dashan; Liu, Binyuan; Zhang, Wenjun; Deng, Ruiping; Zhang, Hongjie

    2008-03-01

    Stable transparent titania thin films were fabricated at room temperature by combining thenoyltrifluoroacetone (TTFA)-modified titanium precursors with amphiphilic triblock poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO, P123) copolymers. The obtained transparent titania thin films were systematically investigated by IR spectroscopy, PL emission and excitation spectroscopy and transmission electron microscopy. IR spectroscopy indicates that TTFA coordinates the titanium center during the process of hydrolysis and condensation. Luminescence spectroscopy confirms the in-situ formation of lanthanide complexes in the transparent titania thin film. TEM image shows that the in-situ formed lanthanide complexes were homogeneously distributed throughout the whole thin film. The quantum yield and the number of water coordinated to lanthanide metal center have been theoretically determined based on the luminescence data.

  13. Electrostatic Self-Assembly Enabling Integrated Bulk and Interfacial Sodium Storage in 3D Titania-Graphene Hybrid

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Xu, Gui-Liang; Xiao, Lisong; Sheng, Tian

    Room temperature sodium-ion batteries have attracted increased attention for energy storage due to the natural abundance of sodium. However, it remains a huge challenge to develop versatile electrode materials with favorable properties, which requires smart structure design and good mechanistic understanding. Herein, we reported a general and scalable approach to synthesize 3D titania-graphene hybrid via electrostatic-interaction-induced self-assembly. Synchrotron X-ray probe, transmission electron microscopy and computational modeling revealed that the strong interaction between Titania and graphene through comparably strong van-der-Waals forces not only facilitates bulk Na+ intercalation but also enhances the interfacial sodium storage. As a result, the titania-graphene hybrid exhibitsmore » exceptional long-term cycle stability up to 5000 cycles, and ultrahigh rate capability up to 20 C for sodium storage. Furthermore, density function theory calculation indicated that the interfacial Li+, K+, Mg2+ and Al3+ storage can be enhanced as well. The proposed general strategy opens up new avenues to create versatile materials for advanced battery systems.« less

  14. Electrostatic Self-Assembly Enabling Integrated Bulk and Interfacial Sodium Storage in 3D Titania-Graphene Hybrid.

    PubMed

    Xu, Gui-Liang; Xiao, Lisong; Sheng, Tian; Liu, Jianzhao; Hu, Yi-Xin; Ma, Tianyuan; Amine, Rachid; Xie, Yingying; Zhang, Xiaoyi; Liu, Yuzi; Ren, Yang; Sun, Cheng-Jun; Heald, Steve M; Kovacevic, Jasmina; Sehlleier, Yee Hwa; Schulz, Christof; Mattis, Wenjuan Liu; Sun, Shi-Gang; Wiggers, Hartmut; Chen, Zonghai; Amine, Khalil

    2018-01-10

    Room-temperature sodium-ion batteries have attracted increased attention for energy storage due to the natural abundance of sodium. However, it remains a huge challenge to develop versatile electrode materials with favorable properties, which requires smart structure design and good mechanistic understanding. Herein, we reported a general and scalable approach to synthesize three-dimensional (3D) titania-graphene hybrid via electrostatic-interaction-induced self-assembly. Synchrotron X-ray probe, transmission electron microscopy, and computational modeling revealed that the strong interaction between titania and graphene through comparably strong van der Waals forces not only facilitates bulk Na + intercalation but also enhances the interfacial sodium storage. As a result, the titania-graphene hybrid exhibits exceptional long-term cycle stability up to 5000 cycles, and ultrahigh rate capability up to 20 C for sodium storage. Furthermore, density function theory calculation indicated that the interfacial Li + , K + , Mg 2+, and Al 3+ storage can be enhanced as well. The proposed general strategy opens up new avenues to create versatile materials for advanced battery systems.

  15. Titania-Coated Silica Alone and Modified by Sodium Alginate as Sorbents for Heavy Metal Ions

    NASA Astrophysics Data System (ADS)

    Kołodyńska, D.; Gęca, M.; Skwarek, E.; Goncharuk, O.

    2018-04-01

    The novel organic-inorganic biohybrid composite adsorbent was synthesized based on nanosized silica-titania modified with alginate within the development of effective adsorbent for heavy metal ions. Effects of metal species Cu(II), Zn(II), Cd(II), and Pb(II); concentrations; pH; temperature; and adsorption onto titania-coated silica (ST20) initial or modified by sodium alginate (ST20-ALG) were studied. The equilibrium and kinetic data of metal ions adsorption were analyzed using Langmuir and Freundlich adsorption models and kinetic models: pseudo first order, pseudo second order, intraparticle kinetic model, and Elovich. The maximum sorption capacities observed were higher for the ST20-ALG composite compared to the initial ST20 oxide for all studied metal ions, namely their values for ST20-ALG were 22.44 mg g- 1 for Cu(II) adsorption, 19.95 mg g- 1 for Zn(II), 18.85 mg g- 1 for Cd(II), and 32.49 mg g- 1 for Pb(II). Structure and properties of initial silica-titania ST20 and modified by sodium alginate ST20-ALG adsorbents were analyzed using nitrogen adsorption/desorption isotherms, ATR-FTIR, SEM-EDS, and pHpzc techniques.

  16. Mechanical optimization of the composite biomaterial based on the tricalcium phosphate, titania and magnesium fluoride.

    PubMed

    Ayadi, Ibticem; Ayed, Foued Ben

    2016-07-01

    The microstructure, the densification and the mechanical properties of the tricalcium phosphate - titania - MgF2 composites were investigated. The effect of MgF2 addition on the performances of the tricalcium phosphate - 40wt% titania composites is discussed. The mechanical properties were investigated by Brazilian test, Vickers indentation and the ultrasound techniques. The mechanical properties of the tricalcium phosphate - 40wt% titania composites reached optimum performances after the sintering process at 1200°C for one hour with 4wt% MgF2. Thus, the highest values of the rupture strength, Vickers hardness, Young׳s and the shear modulus reached 27MPa, 360Hv, 51GPa and 20GPa, respectively. The increase of the mechanical properties of the composites is due to the presence of the liquid phase and the formation of a new compound. Thus, the microstructure of the composites reveals the presence of a new lamella form relative to the Mg2(PO4)F. Beyond 4wt% MgF2, the performances of the composites are hindered by the exaggerated grain growth and the formation of the bubbles. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Cell Attachment and Proliferation of Human Adipose-Derived Stem Cells on PLGA/Chitosan Electrospun Nano-Biocomposite

    PubMed Central

    Razavi, Shahnaz; Karbasi, Saeed; Morshed, Mohammad; Zarkesh Esfahani, Hamid; Golozar, Mohammad; Vaezifar, Sedigheh

    2015-01-01

    Objective In this study, nano-biocomposite composed of poly (lactide-co-glycolide) (PLGA) and chitosan (CS) were electrospun through a single nozzle by dispersing the CS nano-powders in PLGA solution. The cellular behavior of human adipose derived stem cells (h-ADSCs) on random and aligned scaffolds was then evaluated. Materials and Methods In this experimental study, the PLGA/CS scaffolds were prepared at the different ratios of 90/10, 80/20, and 70/30 (w/w) %. Morphology, cell adhesion and prolif- eration rate of h-ADSCs on the scaffolds were assessed using scanning electron microscope (SEM), 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay and trypan blue staining respectively. Results H-ADSCs seeded on the matrices indicated that the PLGA/CS composite matrix with aligned nanofibres and higher content of CS nano-powders gave significantly better performance than others in terms of cell adhesion and proliferation rate (P<0.05). Conclusion We found that CS enhanced cell adhesion and proliferation rate, and aligned nanofibers guided cell growth along the longitudinal axis of the nanofibers, which would provide a beneficial approach for tissue engineering. PMID:26464814

  18. Insights into the Formation and Properties of Templated Dual Mesoporous Titania with Enhanced Photocatalytic Activity.

    PubMed

    Naboulsi, Issam; Lebeau, Bénédicte; Michelin, Laure; Carteret, Cédric; Vidal, Loic; Bonne, Magali; Blin, Jean-Luc

    2017-01-25

    The one pot synthesis of dual mesoporous titania (2.3 and 7.7 nm) has been achieved from a mixture of fluorinated and Pluronic surfactants. The small and large mesopore networks are templated, respectively, by a fluorinated-rich liquid crystal and a Pluronic-rich liquid crystal, which are in equilibrium. After calcination at 350 °C, the amorphous walls are transformed into semicrystalline anatase preserving the mesoporous structure. Results concerning the photodegradation of methyl orange using the calcined photocatalysts highlight that the kinetic rate constant (k) determined for the dual mesoporous titania is 2.6 times higher than the k value obtained for the monomodal ones.

  19. NANOSIZE TITANIA STIMULATES REACTIVE OXYGEN SPECIES IN BRAIN MICROGLIA AND DAMAGES NEURONS.

    EPA Science Inventory

    Research that addresses the environmental impact and biological consequences of widely distributed, commonly used nanoparticles is needed. Nanosize titanium dioxide (i.e., titania, TiO2) is used in air and water remediation and in numerous products designed for direct human us...

  20. Millimeter wave complementary metal-oxide-semiconductor on-chip hexagonal nano-ferrite circulator

    NASA Astrophysics Data System (ADS)

    Chao, Liu; Oukacha, Hassan; Fu, Enjin; Koomson, Valencia Joyner; Afsar, Mohammed N.

    2015-05-01

    Hexagonal ferrites such as M-type BaFe12O19 and SrFe12O19 have strong uniaxial anisotropic magnetic field and remanent magnetism. The nano-sized ferrite powder exhibits high compatibility and processability in composite material. New magnetic devices using the M-type ferrite materials can work in the tens of GHz frequency range from microwave to millimeter wave without the application of strong external magnetic field. The micro- and nano-sized hexagonal ferrite can be conveniently utilized to fabricate magnetic components integrated in CMOS integrated circuits as thin as several micrometers. The micro-fabrication method of such nano ferrite device is presented in this paper. A circulator working at 60 GHz is designed and integrated into the commercial CMOS process. The circulator exhibits distinct circulation properties in the frequency range from 56 GHz to 58 GHz.

  1. Phenazopyridine-phthalimide nano-cocrystal: Release rate and oral bioavailability enhancement.

    PubMed

    Huang, Yu; Li, Jin-Mei; Lai, Zhi-Hui; Wu, Jun; Lu, Tong-Bu; Chen, Jia-Mei

    2017-11-15

    Both cocrystal and nanocrystal technologies have been widely used in the pharmaceutical development for poorly soluble drugs. However, the synergistic effects due to the integration of these two technologies have not been well investigated. The aim of this study is to develop a nano-sized cocrystal of phenazopyridine (PAP) with phthalimide (PI) to enhance the release rate and oral bioavailability of PAP. A PAP-PI nano-cocrystal with particle diameter of 21.4±0.1nm was successfully prepared via a sonochemical approach and characterized by powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and dynamic light scattering (DLS) analysis. An in vitro release study revealed a significant release rate enhancement for PAP-PI nano-cocrystal as compared to PAP-PI cocrystal and PAP hydrochloride salt. Further, a comparative oral bioavailability study in rats indicated significant improvement in C max and oral bioavailability (AUC 0-∞ ) by 1.39- and 2.44-fold, respectively. This study demonstrated that this novel nano-cocrystal technology can be a new promising option to improve release rate and absorption of poorly soluble compounds in the pharmaceutical industry. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. The precursors effects on biomimetic hydroxyapatite ceramic powders.

    PubMed

    Yoruç, Afife Binnaz Hazar; Aydınoğlu, Aysu

    2017-06-01

    In this study, effects of the starting material on chemical, physical, and biological properties of biomimetic hydroxyapatite ceramic powders (BHA) were investigated. Characterization and chemical analysis of BHA powders were performed by using XRD, FT-IR, and ICP-AES. Microstructural features such as size and morphology of the resulting BHA powders were characterized by using BET, nano particle sizer, pycnometer, and SEM. Additionally, biological properties of the BHA ceramic powders were also investigated by using water-soluble tetrazolium salts test (WST-1). According to the chemical analysis of BHA ceramic powders, chemical structures of ceramics which are prepared under different conditions and by using different starting materials show differences. Ceramic powders which are produced at 80°C are mainly composed of hydroxyapatite, dental hydroxyapatite (contain Na and Mg elements in addition to Ca), and calcium phosphate sulfide. However, these structures are altered at high temperatures such as 900°C depending on the features of starting materials and form various calcium phosphate ceramics and/or their mixtures such as Na-Mg-hydroxyapatite, hydroxyapatite, Mg-Whitlockit, and chloroapatite. In vitro cytotoxicity studies showed that amorphous ceramics produced at 80°C and ceramics containing chloroapatite structure as main or secondary phases were found to be extremely cytotoxic. Furthermore, cell culture studies showed that highly crystalline pure hydroxyapatite structures were extremely cytotoxic due to their high crystallinity values. Consequently, the current study indicates that the selection of starting materials which can be used in the production of calcium phosphate ceramics is very important. It is possible to produce calcium phosphate ceramics which have sufficient biocompatibility at physiological pH values and by using appropriate starting materials. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. The influence of mannitol on morphology and disintegration of spray-dried nano-embedded microparticles.

    PubMed

    Torge, Afra; Grützmacher, Philipp; Mücklich, Frank; Schneider, Marc

    2017-06-15

    Nano-embedded microparticles represent a promising approach to deliver nanoparticles to the lungs. Microparticles with an appropriate aerodynamic diameter enable an application by dry powder inhaler and the transport of nanoparticles into the airways. By disintegration after deposition, nanoparticles can be released to exhibit their advantages such as a sustained drug release and delivery of the drug across the mucus barrier. The use of an appropriate matrix excipient to embed the nanoparticles is essential for the necessary disintegration and release of nanoparticles. In this context we investigated the influence of mannitol on the morphology, aerodynamic properties and disintegration behavior of nano-embedded microparticles. PLGA nanoparticles and mannitol were spray dried each as sole component and in combination in three different ratios. An influence of the mannitol content on the morphology was observed. Pure mannitol microparticles were solid and spherical, while the addition of nanoparticles resulted in raisin-shaped hollow particles. The different morphologies can be explained by diffusion processes of the compounds described by the Péclet-number. All powders showed suitable aerodynamic properties. By dispersion of the powders in simulated lung fluid, initial nanoparticle sizes could be recovered for samples containing mannitol. The fraction of redispersed nanoparticles was increased with increasing mannitol content. To evaluate the disintegration under conditions with higher comparability to the in vivo situation, spray-dried powders were exposed to >90% relative humidity. The disintegration behavior was monitored by analyzing roughness values by white light interferometry and supporting SEM imaging. The exposure to high relative humidity was shown to be sufficient for disintegration of the microparticles containing mannitol, releasing morphologically unchanged nanoparticles. With increasing mannitol content, the disintegration occurred faster and to a

  4. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Xu, Hang, E-mail: xhinbj@126.com; Li, Mei; Jun, Zhang

    Graphical abstract: The micro morphological structure of the nano-TiO{sub 2} particles was also observed with TEM, as shown in figure. The TEM images clearly exhibited the homogeneous microstructure of particles with a size of around 10–15 nm. - Highlights: • Nano-TiO{sub 2} was prepared by complex techniques of sol–gel, micro-emulsion and solvent thermal. • The size of TiO{sub 2} was nano level and uniformity. • Nano-TiO{sub 2} exhibited high photo-catalytic activity at internal air lift circulating reactor. • The best nano-TiO{sub 2} dosage was obtained. - Abstract: Anatase nano-titania (TiO{sub 2}) powder was prepared by using a sol–gel process mediatedmore » in reverse microemulsion combined with a solvent thermal technique. The structures of the obtained TiO{sub 2} were characterized by TG-DSC, XRD, TEM. The photocatalytic decomposition of methylene blue (MB) on nano-TiO{sub 2} was studied by using an internal air lift circulating photocatalytic reactor. The results show that the anatase structure appears in the calcination temperature range of 400–510 °C, while the transformation of anatase into rutile takes place above 510 °C. The homogeneous microstructure of nano-TiO{sub 2} particles was obtained with a size of around 10–15 nm. In the photocatalytic performance, degradation process follows pseudo first order kinetics with different dosages of photocatalyst and initial MB concentrations and optimal TiO{sub 2} dosage is 0.1 g/L with neutral medium.« less

  5. Preparation of Nanocrystalline Powders of ZrO2, Stabilized by Y2O3 Dobs for Ceramics

    NASA Astrophysics Data System (ADS)

    Petrunin, V. F.; Korovin, S. A.

    The purpose of this study was to develop a synthesis conditions and produce samples of nanocrystalline zirconia powder in a high-temperature phase state. To increase the stability of this state at room temperature, Y2O3 was used as a dop in the two-stages chemical method including coprecipitation mixture of the corresponding hydroxides and air drying. To reduce agglomeration of nanoparticles during heat treatment of precursors the microwave oven instead of a muffle was used. Different characterisation methods have been used to determine that the obtained powders are nano-scale corresponds to a high-temperature tetragonal phase of ZrO2. It is shown that such nanocrystalline powders may be used to produce highly-dense nanoceramics.

  6. Titania carbon nanotube composites for enhanced photocatalysis

    NASA Astrophysics Data System (ADS)

    Pyrgiotakis, Georgios

    Photocatalytic composites have been used for the past few decades in a wide range of applications. The most common application is the purification of air and water by removing toxic compounds. There is limited use however towards biocidal applications. Despite their high efficiency, photocatalytic materials are not comparable to the effectiveness of conventional biocidal compounds such as chlorine and alcoholic disinfectants. On the other hand, nearly a decade ago with the discovery of the carbon nanotubes a new vibrant scientific field emerged. Nanotubes are unique structures of carbon that posse amazing electrical, mechanical and thermal properties. In this research carbon nanotubes are used as photocatalytic enhancers. They were coated with anatase titania to form a composite material. Two different types of nanotubes (metallic versus non-metallic) were used and the photocatalytic activity was measured. The metallic tubes demonstrated exceptional photocatalytic properties, while non-metallic tubes had low photocatalytic efficiency. The reason for that difference was investigated and was the major focus of this research. The research concluded that the reasons for the high efficiency of the carbon nanotubes were (i) the metallic nature of the tubes and (ii) the possible bond between the titania coating and the underlying graphite layers (C-O-Ti). Since both composites had the same indications regarding the C-O-Ti bond, the metallic nature of the carbon nanotubes is believed to be the most dominant factor contributing to the enhancement of the photocatalysis. The composite material may have other potential applications such as for sensing and photovoltaic uses.

  7. Preparation of the highly dispersed powder of titanium carbonitride by SHS azide technology with previous partial nitriding

    NASA Astrophysics Data System (ADS)

    Amosov, A. P.; Markov, Yu M.; Dobrovolskaya, R. A.; Nikolaeva, E. N.

    2017-02-01

    It is shown that the powder of very hard refractory titanium carbonitride (TiC0.5N0.5) is the basis of tungsten-free hard alloys which are prospective for application as inexpensive cutting tools. The finer the powder of titanium carbonitrideis, the moreenhanced properties of hard alloys, sintered from the powder, are. An opportunity to reduce the particle size of the titanium carbonitride powder obtained by energy-saving azide technology of self-propagating high-temperature synthesis at the cost of reducing the particle size of the initial titanium powderwas investigated. To ensure the safety of the grinding process of the initial metal titanium powder, it was offered to nitride a Ti powder partially into a TiN0.2 compound. Such partial nitriding was performed by the azidetechnology with lack of sodium azide (NaN3) as a nitriding reagent. After intensive grinding in the planetary ball mill, the TiN0.2 powder turned into a superfine powder with an ultrafine structure. This powder was capable of nitriding and carburizing in the azide technology with formation of superfine pure powder agglomerates which are composed of ultrafine and nano-particles of TiC0.5N0.5.

  8. Optical absorption characteristics in the assessment of powder phosphor-based x-ray detectors: from nano- to micro-scale.

    PubMed

    Liaparinos, P F

    2015-11-21

    X-ray phosphor-based detectors have enormously improved the quality of medical imaging examinations through the optimization of optical diffusion. In recent years, with the development of science and technology in the field of materials, improved powder phosphors require structural and optical properties that contribute to better optical signal propagation. The purpose of this paper was to provide a quantitative and qualitative understanding of the optical absorption characteristics in the assessment of powder phosphor-based detectors (from nano- scale up to micro-scale). Variations on the optical absorption parameters (i.e. the light extinction coefficient [Formula: see text] and the percentage probability of light absorption p%) were evaluated based on Mie calculations examining a wide range of light wavelengths, particle refractive indices and sizes. To model and assess the effects of the aforementioned parameters on optical diffusion, Monte Carlo simulation techniques were employed considering: (i) phosphors of different layer thickness, 100 μm (thin layer) and 300 μm (thick layer), respectively, (ii) light extinction coefficient values, 1, 3 and 6 μm(-1), and (iii) percentage probability of light absorption p% in the range 10(-4)-10(-2). Results showed that the [Formula: see text] coefficient is high for phosphor grains in the submicron scale and for low light wavelengths. At higher wavelengths (above 650 nm), optical quanta follow approximately similar depths until interaction for grain diameter 500 nm and 1 μm. Regarding the variability of the refractive index, high variations of the [Formula: see text] coefficient occurred above 1.6. Furthermore, results derived from Monte Carlo modeling showed that high spatial resolution phosphors can be accomplished by increasing the [Formula: see text] parameter. More specifically, the FWHM was found to decrease (i.e. higher resolution): (i) 4.8% at 100 μm and (ii) 9.5%, at 300 μm layer thickness. This study

  9. Probing the Effects of Templating on the UV and Visible Light Photocatalytic Activity of Porous Nitrogen-Modified Titania Monoliths for Dye Removal.

    PubMed

    Nursam, Natalita M; Wang, Xingdong; Tan, Jeannie Z Y; Caruso, Rachel A

    2016-07-13

    Porous nitrogen-modified titania (N-titania) monoliths with tailored morphologies were prepared using phase separation and agarose gel templating techniques. The doping and templating process were simultaneously carried out in a one-pot step using alcohol amine-assisted sol-gel chemistry. The amount of polymer used in the monoliths that were prepared using phase separation was shown to affect both the physical and optical properties: higher poly(ethylene glycol) content increased the specific surface area, porosity, and visible light absorption of the final materials. For the agarose-templated monoliths, the infiltration conditions affected the monolith morphology. A porous monolith with high surface area and the least shrinkage was obtained when the N containing alkoxide precursor was infiltrated into the agarose scaffolds at 60 °C. The effect of the diverse porous morphologies on the photocatalytic activity of N-titania was studied for the decomposition of methylene blue (MB) under visible and UV light irradiation. The highest visible light activity was achieved by the agarose-templated N-titania monolith, in part due to higher N incorporation. This sample also showed better UV activity, partly because of the higher specific surface area (up to 112 m(2) g(-1)) compared to the phase separation-induced monoliths (up to 103 m(2) g(-1)). Overall, agarose-templated, porous N-titania monoliths provided better features for effectively removing the MB contaminant.

  10. Nano-sized, quaternary titanium(IV) metal-organic frameworks with multidentate ligands.

    PubMed

    Baranwal, Balram Prasad; Singh, Alok Kumar

    2010-12-01

    Some mononuclear nano-sized, quaternary titanium(IV) complexes having the general formula [Ti(acac)(OOCR)2(SB)] (where Hacac=acetylacetone, R=C15H31 or C17H35, HSB=Schiff bases) have been synthesized using different multidentate ligands. These were characterized by elemental analyses, molecular weight determinations and spectral (FTIR, 1H NMR and powder XRD) studies. Conductance measurement indicated their non-conducting nature which may behave like insulators. Structural parameters like the values of limiting indices h, k, l, cell constants a, b, c, angles α, β, γ and particle size are calculated from powder XRD data for complex 1 which indicated nano-sized triclinic system in them. Bidentate chelating nature of acetylacetone, carboxylate and Schiff base anions in the complexes was established by their infrared spectra. Molecular weight determinations confirmed mononuclear nature of the complexes. On the basis of physico-chemical studies, coordination number 8 was assigned for titanium(IV) in the complexes. Transmission electron microscopy (TEM) and the selected area electron diffraction (SAED) studies indicated spherical particles with poor crystallinity. Copyright © 2010 Elsevier B.V. All rights reserved.

  11. Sonochemical syntheses of a new nano-sized porous lead(II) coordination polymer as precursor for preparation of lead(II) oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Ranjbar, Zohreh Rashidi; Morsali, Ali

    2009-11-01

    Nano-scale of a new Pb(II) coordination polymer, {[Pb(bpacb)(OAc)]·DMF} n ( 1); bpacbH = 3,5-bis[(4-pyridylamino)carbonyl]benzoic acid], were synthesized by a sonochemical method. The nano-material was characterized by scanning electron microscopy, X-ray powder diffraction (XRD), 1H, 13C NMR, IR spectroscopy and elemental analyses. Crystal structure of compound 1 was determined by X-ray crystallography. Calcination of the nano-sized compound 1 at 700 °C under air atmospheres yields PbO nanoparticles. Thermal stability of nano-sized and single crystalline samples of compound 1 were studied and compared with each other.

  12. The detection of improvised nonmilitary peroxide based explosives using a titania nanotube array sensor.

    PubMed

    Banerjee, Subarna; Mohapatra, Susanta K; Misra, Mano; Mishra, Indu B

    2009-02-18

    There is a critical need to develop an efficient, reliable and highly selective sensor for the detection of improvised nonmilitary explosives. This paper describes the utilization of functionalized titania nanotube arrays for sensing improvised organic peroxide explosives such as triacetone triperoxide (TATP). TATP forms complexes with titania nanotube arrays (prepared by anodization and sensitized with zinc ions) and thus affects the electron state of the nanosensing device, which is signaled as a change in current of the overall nanotube material. The response is rapid and a signal of five to eight orders of magnitude is observed. These nanotube array sensors can be used as hand-held miniaturized devices as well as large scale portable units for military and homeland security applications.

  13. In-situ fabrication of zirconium-titanium nano-composite and its coating on Ti-6Al-4V for biomedical applications.

    PubMed

    Chellappa, Manickam; Vijayalakshmi, Uthirapathy

    2017-02-01

    In this study, nanocomposite powder consisting of zirconia and titania (Zr-Ti) have been synthesised by sol-gel method, with the aim of protecting Ti-6Al-4V surface. A simple and low cost electrophoretic deposition (EPD) technique has been employed for coating the nanocomposite material on Ti-6Al-4V. The prepared nanocomposite powder was characterised for its functional groups, phase purity, surface topography by Fourier transform infrared spectroscopy, powder X-ray diffraction and scanning electron microscopy. Further, the biocompatibility nature of the composite powder was studied by [3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide] colorimetric assay and fluorescence analysis with MG63 osteoblast cell lines. The electrochemical behaviour of composite coating was investigated by potentiodynamic polarization and electrochemical impedance method. The results obtained from the electrochemical techniques indicate more corrosion resistance behaviour with increase of R ct value with the corresponding decrease in R dl values. From the above findings, the composite coating acts as a barrier layer against corrosion by preventing the leaching of metal ions from a dense and defect free coating. A scratch test analyser was used to assess the integrity of the coating; the lower traction force value of composite coating with increase in load has confirmed the presence of thick adherent layer on the substrate.

  14. Processing and characterization of powdered silk micro- and nanofibers by ultrasonication.

    PubMed

    Wang, Hai-Yan; Chen, Yun-Yun; Zhang, Yu-Qing

    2015-03-01

    Silk derived from Bombyx mori silkworm cocoons was degummed in an aqueous sodium carbonate solution, and the resulting silk fibroin fibers were placed in an acidic aqueous solution and were treated with ultrasonication to obtain powdered micro- and nanofibers. The morphologies and spectral characteristics of these powdered silk fibers were investigated in detail. The shape, surface and structural features of the powdered fibers were affected by the ultrasonic power and media. Increasing the acidity of the ultrasonic solution and increasing the ultrasonic power increased the fiber breakage speed, resulting in shorter fiber lengths. Powdered microfibers could not be obtained in a formic acid solution, while powdered nanofibers whose diameter below 1μm were obtained in a combined formic acid and hydrochloric acid ultrasonication solution. Observation via SEM and optical microscopy revealed that the microfiber diameters were approximately 5-10μm, and those of the nanofibers were approximately 30-120nm. The analysis of laser sizer showed that the microfiber sizes ranged mainly from 20 to 100μm. FT-IR and XRD spectra demonstrated that the relative amount of β-sheets increased after the ultrasonic treatment. The ε-amino group content on the surface of the micro- and nanofibers increased significantly. These studies provide reliable methods for the preparation of nano-scale silk fibroin fibers by ultrasonication and open new avenues for the development of powdered silk fibers as advanced functional biomaterials. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Comparison of the cohesive and delamination fatigue properties of atomic-layer-deposited alumina and titania ultrathin protective coatings deposited at 200 °C

    PubMed Central

    Sadeghi-Tohidi, Farzad; Samet, David; Graham, Samuel; Pierron, Olivier N

    2014-01-01

    The fatigue properties of ultrathin protective coatings on silicon thin films were investigated. The cohesive and delamination fatigue properties of 22 nm-thick atomic-layered-deposited (ALD) titania were characterized and compared to that of 25 nm-thick alumina. Both coatings were deposited at 200 °C. The fatigue rates are comparable at 30 °C, 50% relative humidity (RH) while they are one order of magnitude larger for alumina compared to titania at 80 °C, 90% RH. The improved fatigue performance is believed to be related to the improved stability of the ALD titania coating with water compared to ALD alumina, which may in part be related to the fact that ALD titania is crystalline, while ALD alumina is amorphous. Static fatigue crack nucleation and propagation was not observed. The underlying fatigue mechanism is different from previously documented mechanisms, such as stress corrosion cracking, and appears to result from the presence of compressive stresses and a rough coating–substrate interface. PMID:27877645

  16. Investigation of advanced nanostructured multijunction photoanodes for enhanced solar hydrogen generation via water splitting

    NASA Astrophysics Data System (ADS)

    Ishihara, Hidetaka

    As the worldwide demand for fossil-based fuel increases every day and the fossil reserve continues to be depleted, the need for alternative/renewable energy sources has gained momentum. Electric, hybrid, and hydrogen cars have been at the center of discussion lately among consumers, automobile manufacturers, and politicians, alike. The development of a fuel-cell based engine using hydrogen has been an ambitious research area over the last few decades-ever since Fujishima showed that hydrogen can be generated via the solar-energy driven photo-electrolytic splitting of water. Such solar cells are known as Photo-Electro-Chemical (PEC) solar cells. In order to commercialize this technology, various challenges associated with photo-conversion efficiency, chemical corrosion resistance, and longevity need to be overcome. In general, metal oxide semiconductors such as titanium dioxide (TiO 2, titania) are excellent candidates for PEC solar cells. Titania nanotubes have several advantages, including biocompatibility and higher chemical stability. Nevertheless, they can absorb only 5-7% of the solar spectrum which makes it difficult to achieve the higher photo-conversion efficiency required for successful commercial applications. A two-prong approach was employed to enhance photo-conversion efficiency: 1) surface modification of titania nanotubes using plasma treatment and 2) nano-capping of the titania nanotubes using titanium disilicide. The plasma surface treatment with N2 was found to improve the photo-current efficiency of titania nanotubes by 55%. Similarly, a facile, novel approach of nano-capping titania nanotubes to enhance their photocurrent response was also investigated. Electrochemically anodized titania nanotubes were capped by coating a 25 nm layer of titanium disilicide using RF magnetron sputtering technique. The optical properties of titania nanotubes were not found to change due to the capping; however, a considerable increase (40%) in the photocurrent

  17. Depositing laser-generated nanoparticles on powders for additive manufacturing of oxide dispersed strengthened alloy parts via laser metal deposition

    NASA Astrophysics Data System (ADS)

    Streubel, René; Wilms, Markus B.; Doñate-Buendía, Carlos; Weisheit, Andreas; Barcikowski, Stephan; Henrich Schleifenbaum, Johannes; Gökce, Bilal

    2018-04-01

    We present a novel route for the adsorption of pulsed laser-dispersed nanoparticles onto metal powders in aqueous solution without using any binders or surfactants. By electrostatic interaction, we deposit Y2O3 nanoparticles onto iron-chromium based powders and obtain a high dispersion of nano-sized particles on the metallic powders. Within the additively manufactured component, we show that the particle spacing of the oxide inclusion can be adjusted by the initial mass fraction of the adsorbed Y2O3 particles on the micropowder. Thus, our procedure constitutes a robust route for additive manufacturing of oxide dispersion-strengthened alloys via oxide nanoparticles supported on steel micropowders.

  18. Effective coating of titania nanoparticles with alumina via atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Azizpour, H.; Talebi, M.; Tichelaar, F. D.; Sotudeh-Gharebagh, R.; Guo, J.; van Ommen, J. R.; Mostoufi, N.

    2017-12-01

    Alumina films were deposited on titania nanoparticles via atomic layer deposition (ALD) in a fluidized bed reactor at 180 °C and 1 bar. Online mass spectrometry was used for real time monitoring of effluent gases from the reactor during each reaction cycle in order to determine the optimal dosing time of precursors. Different oxygen sources were used to see which oxygen source, in combination with trimethyl aluminium (TMA), provides the highest alumina growth per cycle (GPC). Experiments were carried out in 4, 7 and 10 cycles using the optimal dosing time of precursors. Several characterization methods, such as high resolution transmission electron microscopy (HRTEM), Brunauer-Emmett-Teller (BET), energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared (FTIR), X-ray diffraction (XRD) and instrumental neutron activation analysis (INAA), were conducted on the products. Formation of the alumina film was confirmed by EDX mapping and EDX line profiling, FTIR and TEM. When using either water or deuterium oxide as the oxygen source, the thickness of the alumina film was greater than that of ozone. The average GPC measured by TEM for the ALD of TMA with water, deuterium oxide and ozone was about 0.16 nm, 0.15 nm and 0.11 nm, respectively. The average GPC calculated using the mass fraction of aluminum from INAA was close to those measured from TEM images. Excess amounts of precursors lead to a higher average growth of alumina film per cycle due to insufficient purging time. XRD analysis demonstrated that amorphous alumina was coated on titania nanoparticles. This amorphous layer was easily distinguished from the crystalline core in the TEM images. Decrease in the photocatalytic activity of titania nanoparticles after alumina coating was confirmed by measuring degradation of Rhodamine B by ultraviolet irradiation.

  19. Observations of Time Variable Magnitude Events of Phoebe, Ariel, and Titania

    NASA Astrophysics Data System (ADS)

    Miller, Charles; Chanover, N. J.; Holtzman, J. A.; Verbiscer, A. J.

    2007-10-01

    Visual observations of Saturn's moon Phoebe and Uranus' moons Ariel and Titania were made from the Apache Point Observatory (APO). Phoebe was observed with the APO 1 meter telescope over a two month period from 06 January to 04 March 2005, bracketing the zero-phase opposition on 13 January 2005. Phoebe was observed at Sun-Phoebe-Earth phase angles as low as 0.05 degrees on consecutive nights immediately before and after opposition in V, B, R, and I filters. Light curves of the opposition surge, the brightness increase that occurs as the phase angle drops below 0.10 degrees, are presented from this data. The data were processed using standard IRAF aperture photometry image processing techniques. The magnitude and duration of the opposition surge provide clues about the grain size of surface particles on Phoebe. Observations were also made of Uranian moons during mutual occultations in August 2007. Mutual satellite occultations are taking place throughout 2007 as Uranus passes through its equinox, which occurs once every 42 years. The timing and flux variation of satellite occultations provide a check on the accuracy of satellite orbital models. Light curves for Ariel and Titania in R and I filters as they are occulted by Umbriel are presented from data acquired with the APO 1 meter and 3.5 meter telescopes. Comparison is made to the predicted total flux reduction and event timing for each occultation as calculated by the Institut de Mecanique Celeste et de Calcul des Ephemerides (IMCCE) and implications of the results on determination of the relative orbital inclinations of Umbriel, Ariel, and Titania are discussed. This work was supported by an NMSU Space and Aerospace Research Cluster Graduate Fellowship .

  20. Fabrication and mechanical evaluation of hydroxyapatite/oxide nano-composite materials.

    PubMed

    Mohamed, Khaled R; Beherei, Hanan H; El Bassyouni, Gehan T; El Mahallawy, Nahed

    2013-10-01

    In the current study, the semiconducting metal oxides such as nano-ZnO and SiO2 powders were prepared via sol-gel technique and conducted on nano-hydroxyapatite (nHA) which was synthesized by chemical precipitation. The properties of fabricated nano-structured composites containing different ratios of HA, ZnO and SiO2 were examined using X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscope (SEM) and transmission electron microscope (TEM) techniques. The effect of the variation of ratios between the three components on mechanical, microstructure and in-vitro properties was assessed to explore the possibility of enhancing these properties. The results proved that the mechanical properties exhibited an increment with increasing the ZnO content at the extent of HA. In-vitro study proved the formation and nucleation of apatite onto the surface of the fabricated composites after one week of immersion. It is concluded that HA composites containing SiO2 or SiO2/ZnO content had a suitable mechanical properties and ability to form apatite particles onto the composite surface. Based on bioactivity behavior, Si-HA is more bioactive than pure hydroxyapatite and nano-arrangements will provide an interface for better bone formation. Therefore, these nano-composites will be promising as bone substitutes especially in load bearing sites. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Mechanochemical synthesis of fluorescent carbon dots from cellulose powders

    NASA Astrophysics Data System (ADS)

    Chae, Ari; Ram Choi, Bo; Choi, Yujin; Jo, Seongho; Kang, Eun Bi; Lee, Hyukjin; Park, Sung Young; In, Insik

    2018-04-01

    A novel mechanochemical method was firstly developed to synthesize carbon nanodots (CNDs) or carbon nano-onions (CNOs) through high-pressure homogenization of cellulose powders as naturally abundant resource depending on the treatment times. While CNDs (less than 5 nm in size) showed spherical and amorphous morphology, CNOs (10-50 nm in size) presented polyhedral shape, and onion-like outer lattice structure, graphene-like interlattice spacing of 0.36 nm. CNOs showed blue emissions, moderate dispersibility in aqueous media, and high cell viability, which enables efficient fluorescence imaging of cellular media.

  2. Biocompatibility of sol-gel-derived titania-silica coated intramedullary NiTi nails.

    PubMed

    Muhonen, V; Kujala, S; Vuotikka, A; Aäritalo, V; Peltola, T; Areva, S; Närhi, T; Tuukkanen, J

    2009-02-01

    We investigated bone response to sol-gel-derived titania-silica coated functional intramedullary NiTi nails that applied a continuous bending force. Nails 26 mm in length, either straight or with a radius of curvature of 28 or 15 mm, were implanted in the cooled martensite form from a proximal to distal direction into the medullary cavity of the right femur in 40 Sprague-Dawley rats. Body temperature restored the austenite form, causing the curved implants to generate a bending force on the bone. The femurs were examined after 24 weeks. Bone length measurements did not reveal any bowing or shortening of the bone in the experimental groups. The results from histomorphometry demonstrated that the stronger bending force, together with sol-gel surface treatment, resulted in more bone deposition around the implant and the formation of significantly less fibrous tissue. Straight intramedullary nails, even those with a titania-silica coating, were poorly attached when compared to the implants with a curved austenite structure.

  3. Nano-tubular cellulose for bioprocess technology development.

    PubMed

    Koutinas, Athanasios A; Sypsas, Vasilios; Kandylis, Panagiotis; Michelis, Andreas; Bekatorou, Argyro; Kourkoutas, Yiannis; Kordulis, Christos; Lycourghiotis, Alexis; Banat, Ibrahim M; Nigam, Poonam; Marchant, Roger; Giannouli, Myrsini; Yianoulis, Panagiotis

    2012-01-01

    Delignified cellulosic material has shown a significant promotional effect on the alcoholic fermentation as yeast immobilization support. However, its potential for further biotechnological development is unexploited. This study reports the characterization of this tubular/porous cellulosic material, which was done by SEM, porosimetry and X-ray powder diffractometry. The results showed that the structure of nano-tubular cellulose (NC) justifies its suitability for use in "cold pasteurization" processes and its promoting activity in bioprocessing (fermentation). The last was explained by a glucose pump theory. Also, it was demonstrated that crystallization of viscous invert sugar solutions during freeze drying could not be otherwise achieved unless NC was present. This effect as well as the feasibility of extremely low temperature fermentation are due to reduction of the activation energy, and have facilitated the development of technologies such as wine fermentations at home scale (in a domestic refrigerator). Moreover, NC may lead to new perspectives in research such as the development of new composites, templates for cylindrical nano-particles, etc.

  4. Pozzolanic activity and durability of nano silica, micro silica and silica gel contained concrete

    NASA Astrophysics Data System (ADS)

    Al Ghabban, Ahmed; Al Zubaidi, Aseel B.; Fakhri, Zahraa

    2018-05-01

    This paper aims to investigate the influence of replacement of cement with nano silica, micro silica and silica gel admixtures on pozzolanic activity, the replacement ratio was10% for all admixture, silica gel used in two forms (beads and crushed powder). Also, the water absorption test was investigated for obtaining the durability properties of concrete, in specimens for this test admixtures were added in four different dosages 1%, 2%, 3% and 4% by weight of the cementitious material into the concrete mixture. Experimental investigations of modified concrete were conducted after 28 days of water curing. Results showed that mixes of nano silica and crushed silica gel showed a higher pozzolanic activity index. For the water absorption test, all mixes incorporating nano silica, micro silica and silica gel showed lower absorption than control mixes best result were noticed with crushed silica gel and nano silica mixes. DTA analysis confirms the results for both poisonous activity and water absorption.

  5. Phenotypic and genomic responses to titanium dioxide and cerium oxide nanoparticles in Arabidopsis germinants

    EPA Science Inventory

    The effects of exposure to two nanoparticles (NPs) -titanium dioxide (nano-titania) and cerium oxide (nano-ceria) at 500 mg NPs L-1 on gene expression and growth in Arabidopsis thaliana germinants were studied using microarrays and phenotype studies. After 12 days post treatment,...

  6. Ultrasonic degradation of aqueous phenolsulfonphthalein (PSP) in the presence of nano-Fe/H2O2.

    PubMed

    Ayanda, Olushola S; Nelana, Simphiwe M; Naidoo, Eliazer B

    2018-10-01

    In this study, nano iron (nano-Fe) was successfully synthesized by sodium borohydride reduction of ferric chloride solution to enhance the ultrasonic degradation of phenolsulfonphthalein (PSP). The nano-Fe was characterized by scanning electron microscopy - energy dispersive spectroscopy (SEM-EDX), transmission electron microscopy (TEM), powder X-ray diffraction (XRD), attenuated total reflection - Fourier transform infrared spectroscopy (ATR-FTIR), and Brunauer, Emmett and Teller (BET) surface area determination. Experimental results demonstrated that a combined ultrasonic/nano-Fe/H 2 O 2 system was more effective for PSP removal in combination than they were individually and there was a significant difference between the combined and single processes. The ultrasonic/nano-Fe/H 2 O 2 degradation follows the Langmuir-Hinshelwood (L-H) kinetic model. The addition of nano-Fe and H 2 O 2 to the ultrasonic reactor greatly accelerated the degradation of PSP (25 mg/L) from 12.5% up to 96.5%. These findings indicated that ultrasonic degradation in the presence of nano-Fe and H 2 O 2 is a promising and efficient technique for the elimination of emerging micropollutants from aqueous solution. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. Forging of metallic nano-objects for the fabrication of submicron-size components

    NASA Astrophysics Data System (ADS)

    Rösler, J.; Mukherji, D.; Schock, K.; Kleindiek, S.

    2007-03-01

    In recent years, nanoscale fabrication has developed considerably, but the fabrication of free-standing nanosize components is still a great challenge. The fabrication of metallic nanocomponents utilizing three basic steps is demonstrated here. First, metallic alloys are used as factories to produce a metallic raw stock of nano-objects/nanoparticles in large numbers. These objects are then isolated from the powder containing thousands of such objects inside a scanning electron microscope using manipulators, and placed on a micro-anvil or a die. Finally, the shape of the individual nano-object is changed by nanoforging using a microhammer. In this way free-standing, high-strength, metallic nano-objects may be shaped into components with dimensions in the 100 nm range. By assembling such nanocomponents, high-performance microsystems can be fabricated, which are truly in the micrometre scale (the size ratio of a system to its component is typically 10:1).

  8. Rapid and direct detection of attomole adenosine triphosphate (ATP) by MALDI-MS using rutile titania chips.

    PubMed

    Manikandan, Muthu; Hasan, Nazim; Wu, Hui-Fen

    2012-11-07

    We report the rutile titania-based capture of ATP and its application as a MALDI-MS target plate. This chip, when immersed in solutions containing different concentrations of ATP, can capture ATP and lead to its successful detection in MALDI-MS. We have optimized the ideal surface, showing an increased capture efficacy of the 900 °C (rutile) titania surfaces. We demonstrate the use of this chip as a target plate for direct analysis of the attached ATP using MALDI-MS, down to attomolar concentrations. This chip has a promising future for the detection of ATP in environmental samples, which may eventually be used as a pollution indicator in particular environments.

  9. Biochar composites with nano zerovalent iron and eggshell powder for nitrate removal from aqueous solution with coexisting chloride ions.

    PubMed

    Ahmad, Munir; Ahmad, Mahtab; Usman, Adel R A; Al-Faraj, Abdullah S; Abduljabbar, Adel S; Al-Wabel, Mohammad I

    2017-09-18

    Biochar (BC) was produced from date palm tree leaves and its composites were prepared with nano zerovalent iron (nZVI-BC) and hen eggshell powder (EP-BC). The produced BC and its composites were characterized by SEM, XRD, BET, and FTIR for surface structural, mineralogical, and chemical groups and tested for their efficiency for nitrate removal from aqueous solutions in the presence and absence of chloride ions. The incidence of graphene and nano zerovalent iron (Fe 0 ) in the nZVI-BC composite was confirmed by XRD. The nZVI-BC composite possessed highest surface area (220.92 m 2  g -1 ), carbon (80.55%), nitrogen (3.78%), and hydrogen (11.09%) contents compared to other materials. Nitrate sorption data was fitted well to the Langmuir (R 2  = 0.93-0.98) and Freundlich (R 2  = 0.90-0.99) isotherms. The sorption kinetics was adequately explained by the pseudo-second-order, power function, and Elovich models. The nZVI-BC composite showed highest Langmuir predicted sorption capacity (148.10 mg g -1 ) followed by EP-BC composite (72.77 mg g -1 ). In addition to the high surface area, the higher nitrate removal capacity of nZVI-BC composite could be attributed to the combination of two processes, i.e., chemisorption (outer-sphere complexation) and reduction of nitrate to ammonia or nitrogen by Fe 0 . The appearance of Fe-O stretching and N-H bonds in post-sorption FTIR spectra of nZVI-BC composite suggested the occurrence of redox reaction and formation of Fe compound with N, such as ferric nitrate (Fe(NO 3 ) 3 ·9H 2 O). Coexistence of chloride ions negatively influenced the nitrate sorption. The decrease in nitrate sorption with increasing chloride ion concentration was observed, which could be due to the competition of free active sites on the sorbents between nitrate and chloride ions. The nZVI-BC composite exhibited higher nitrate removal efficiency compared to other materials even in the presence of highest concentration (100 mg L -1 ) of coexisting

  10. Nano-technology and nano-toxicology.

    PubMed

    Maynard, Robert L

    2012-01-01

    Rapid developments in nano-technology are likely to confer significant benefits on mankind. But, as with perhaps all new technologies, these benefits are likely to be accompanied by risks, perhaps by new risks. Nano-toxicology is developing in parallel with nano-technology and seeks to define the hazards and risks associated with nano-materials: only when risks have been identified they can be controlled. This article discusses the reasons for concern about the potential effects on health of exposure to nano-materials and relates these to the evidence of the effects on health of the ambient aerosol. A number of hypotheses are proposed and the dangers of adopting unsubstantiated hypotheses are stressed. Nano-toxicology presents many challenges and will need substantial financial support if it is to develop at a rate sufficient to cope with developments in nano-technology.

  11. Nano-technology and nano-toxicology

    PubMed Central

    Maynard, Robert L.

    2012-01-01

    Rapid developments in nano-technology are likely to confer significant benefits on mankind. But, as with perhaps all new technologies, these benefits are likely to be accompanied by risks, perhaps by new risks. Nano-toxicology is developing in parallel with nano-technology and seeks to define the hazards and risks associated with nano-materials: only when risks have been identified they can be controlled. This article discusses the reasons for concern about the potential effects on health of exposure to nano-materials and relates these to the evidence of the effects on health of the ambient aerosol. A number of hypotheses are proposed and the dangers of adopting unsubstantiated hypotheses are stressed. Nano-toxicology presents many challenges and will need substantial financial support if it is to develop at a rate sufficient to cope with developments in nano-technology. PMID:22662021

  12. Modulation of the nanometer pore size improves magnesium adsorption into mesoporous titania coatings and promotes bone morphogenic protein 4 expression in adhering osteoblasts.

    PubMed

    Cecchinato, Francesca; Atefyekta, Saba; Wennerberg, Ann; Andersson, Martin; Jimbo, Ryo; Davies, Julia R

    2016-07-01

    Mesoporous (MP) titania films used as implant coatings have recently been considered as release systems for controlled administration of magnesium to enhance initial osteoblast proliferation in vitro. Tuning of the pore size in such titania films is aimed at increasing the osteogenic potential through effects on the total loading capacity and the release profile of magnesium. In this study, evaporation-induced self-assembly (EISA) was used with different structure-directing agents to form three mesoporous films with average pore sizes of 2nm (MP1), 6nm (MP2) and 7nm (MP3). Mg adsorption and release was monitored using quartz crystal microbalance with dissipation (QCM-D). The film surfaces were characterized with atomic force microscopy (AFM), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The effect of different Mg release on osteogenesis was investigated in human fetal osteoblasts (hFOB) using pre-designed osteogenesis arrays and real-time polymerase chain reaction (RT-PCR). Results showed a sustained release from all the films investigated, with higher magnesium adsorption into MP1 and MP3 films. No significant differences were observed in the surface nanotopography of the films, either with or without the presence of magnesium. MP3 films (7nm pore size) had the greatest effect on osteogenesis, up-regulating 15 bone-related genes after 1 week of hFOB growth and significantly promoting bone morphogenic protein (BMP4) expression after 3 weeks of growth. The findings indicate that the increase in pore width on the nano scale significantly enhanced the bioactivity of the mesoporous coating, thus accelerating osteogenesis without creating differences in surface roughness. Copyright © 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  13. Hybrid Dye-Sensitized Solar Cells Consisting of Double Titania Layers for Harvesting Light with Wide Range of Wavelengths

    NASA Astrophysics Data System (ADS)

    Sadamasu, Kengo; Inoue, Takafumi; Ogomi, Yuhei; Pandey, Shyam S.; Hayase, Shuzi

    2011-02-01

    We report a hybrid dye-sensitized solar cell consisting of double titania layers (top and bottom layers) stained with two dyes. A top layer fabricated on a glass was mechanically pressed with a bottom layer fabricated on a glass cloth. The glass cloth acts as a supporter of a porous titania layer as well as a holder of electrolyte. The incident photon to current efficiency (IPCE) curve had two peaks corresponding to those of the two dyes, which demonstrates that electrons are collected from both the top and bottom layers.

  14. Titania's radius and an upper limit on its atmosphere from the September 8, 2001 stellar occultation

    NASA Astrophysics Data System (ADS)

    Widemann, T.; Sicardy, B.; Dusser, R.; Martinez, C.; Beisker, W.; Bredner, E.; Dunham, D.; Maley, P.; Lellouch, E.; Arlot, J.-E.; Berthier, J.; Colas, F.; Hubbard, W. B.; Hill, R.; Lecacheux, J.; Lecampion, J.-F.; Pau, S.; Rapaport, M.; Roques, F.; Thuillot, W.; Hills, C. R.; Elliott, A. J.; Miles, R.; Platt, T.; Cremaschini, C.; Dubreuil, P.; Cavadore, C.; Demeautis, C.; Henriquet, P.; Labrevoir, O.; Rau, G.; Coliac, J.-F.; Piraux, J.; Marlot, Ch.; Marlot, C.; Gorry, F.; Sire, C.; Bayle, B.; Simian, E.; Blommers, A. M.; Fulgence, J.; Leyrat, C.; Sauzeaud, C.; Stephanus, B.; Rafaelli, T.; Buil, C.; Delmas, R.; Desnoux, V.; Jasinski, C.; Klotz, A.; Marchais, D.; Rieugnié, M.; Bouderand, G.; Cazard, J.-P.; Lambin, C.; Pujat, P.-O.; Schwartz, F.; Burlot, P.; Langlais, P.; Rivaud, S.; Brochard, E.; Dupouy, Ph.; Lavayssière, M.; Chaptal, O.; Daiffallah, K.; Clarasso-Llauger, C.; Aloy Doménech, J.; Gabaldá-Sánchez, M.; Otazu-Porter, X.; Fernández, D.; Masana, E.; Ardanuy, A.; Casas, R.; Ros, J. A.; Casarramona, F.; Schnabel, C.; Roca, A.; Labordena, C.; Canales-Moreno, O.; Ferrer, V.; Rivas, L.; Ortiz, J. L.; Fernández-Arozena, J.; Martín-Rodríguez, L. L.; Cidadão, A.; Coelho, P.; Figuereido, P.; Gonçalves, R.; Marciano, C.; Nunes, R.; Ré, P.; Saraiva, C.; Tonel, F.; Clérigo, J.; Oliveira, C.; Reis, C.; Ewen-Smith, B. M.; Ward, S.; Ford, D.; Gonçalves, J.; Porto, J.; Laurindo Sobrinho, J.; Teodoro de Gois, F.; Joaquim, M.; Afonso da Silva Mendes, J.; van Ballegoij, E.; Jones, R.; Callender, H.; Sutherland, W.; Bumgarner, S.; Imbert, M.; Mitchell, B.; Lockhart, J.; Barrow, W.; Cornwall, D.; Arnal, A.; Eleizalde, G.; Valencia, A.; Ladino, V.; Lizardo, T.; Guillén, C.; Sánchez, G.; Peña, A.; Radaelli, S.; Santiago, J.; Vieira, K.; Mendt, H.; Rosenzweig, P.; Naranjo, O.; Contreras, O.; Díaz, F.; Guzmán, E.; Moreno, F.; Omar Porras, L.; Recalde, E.; Mascaró, M.; Birnbaum, C.; Cósias, R.; López, E.; Pallo, E.; Percz, R.; Pulupa, D.; Simbaña, X.; Yajamín, A.; Rodas, P.; Denzau, H.; Kretlow, M.; Valdés Sada, P.; Hernández, R.; Hernández, A.; Wilson, B.; Castro, E.; Winkel, J. M.

    2009-02-01

    On September 8, 2001 around 2 h UT, the largest uranian moon, Titania, occulted Hipparcos star 106829 (alias SAO 164538, a V=7.2, K0 III star). This was the first-ever observed occultation by this satellite, a rare event as Titania subtends only 0.11 arcsec on the sky. The star's unusual brightness allowed many observers, both amateurs or professionals, to monitor this unique event, providing fifty-seven occultations chords over three continents, all reported here. Selecting the best 27 occultation chords, and assuming a circular limb, we derive Titania's radius: R=788.4±0.6km ( 1-σ error bar). This implies a density of ρ=1.711±0.005gcm using the value GM=(2.343±0.006)×10ms derived by Taylor [Taylor, D.B., 1998. Astron. Astrophys. 330, 362-374]. We do not detect any significant difference between equatorial and polar radii, in the limit r-r=-1.3±2.1km, in agreement with Voyager limb image retrieval during the 1986 flyby. Titania's offset with respect to the DE405 + URA027 (based on GUST86 theory) ephemeris is derived: Δαcos(δ)=-108±13 mas and Δδ=-62±7 mas (ICRF J2000.0 system). Most of this offset is attributable to a Uranus' barycentric offset with respect to DE405, that we estimate to be: Δαcos(δ)=-100±25mas and Δδ=-85±25 mas at the moment of occultation. This offset is confirmed by another Titania stellar occultation observed on August 1st, 2003, which provides an offset of Δαcos(δ)=-127±20 mas and Δδ=-97±13 mas for the satellite. The combined ingress and egress data do not show any significant hint for atmospheric refraction, allowing us to set surface pressure limits at the level of 10-20 nbar. More specifically, we find an upper limit of 13 nbar ( 1-σ level) at 70 K and 17 nbar at 80 K, for a putative isothermal CO 2 atmosphere. We also provide an upper limit of 8 nbar for a possible CH 4 atmosphere, and 22 nbar for pure N 2, again at the 1-σ level. We finally constrain the stellar size using the time-resolved star disappearance

  15. Critical aspects in the production of periodically ordered mesoporous titania thin films

    NASA Astrophysics Data System (ADS)

    Soler-Illia, Galo J. A. A.; Angelomé, Paula C.; Fuertes, M. Cecilia; Grosso, David; Boissiere, Cedric

    2012-03-01

    Periodically ordered mesoporous titania thin films (MTTF) present a high surface area, controlled porosity in the 2-20 nm pore diameter range and an amorphous or crystalline inorganic framework. These materials are nowadays routinely prepared by combining soft chemistry and supramolecular templating. Photocatalytic transparent coatings and titania-based solar cells are the immediate promising applications. However, a wealth of new prospective uses have emerged on the horizon, such as advanced catalysts, perm-selective membranes, optical materials based on plasmonics and photonics, metamaterials, biomaterials or new magnetic nanocomposites. Current and novel applications rely on the ultimate control of the materials features such as pore size and geometry, surface functionality and wall structure. Even if a certain control of these characteristics has been provided by the methods reported so far, the needs for the next generation of MTTF require a deeper insight in the physical and chemical processes taking place in their preparation and processing. This article presents a critical discussion of these aspects. This discussion is essential to evolve from know-how to sound knowledge, aiming at a rational materials design of these fascinating systems.Periodically ordered mesoporous titania thin films (MTTF) present a high surface area, controlled porosity in the 2-20 nm pore diameter range and an amorphous or crystalline inorganic framework. These materials are nowadays routinely prepared by combining soft chemistry and supramolecular templating. Photocatalytic transparent coatings and titania-based solar cells are the immediate promising applications. However, a wealth of new prospective uses have emerged on the horizon, such as advanced catalysts, perm-selective membranes, optical materials based on plasmonics and photonics, metamaterials, biomaterials or new magnetic nanocomposites. Current and novel applications rely on the ultimate control of the materials

  16. Investigation of the optical property and photocatalytic activity of mixed phase nanocrystalline titania

    NASA Astrophysics Data System (ADS)

    Paul, Susmita; Choudhury, Amarjyoti

    2014-10-01

    Mixed phase nanocrystalline titania are prepared by simple sol-gel method. The physico-chemical characteristics of the prepared nanoparticles are studied with X-ray diffraction, high-resolution transmission electron microscopy, RAMAN, BET, UV-Vis, steady state and time resolved photoluminescence. X-ray diffraction and Raman spectra clearly demarcate the anatase and rutile phase as both the phases give different diffraction patterns and Raman peaks. A comparison in the band gap indicates that pure anatase and rutile phase have band gap in the UV region, whereas a mixture of these phases has lower band gap and corresponds to the visible region. Steady state and time resolved photoluminescence are employed to understand the emissivity and carrier lifetime. The photocatalytic activity is evaluated by monitoring the degradation of phenol under visible light illumination. Due to the synergistic effect of mixed anatase and rutile phases, mixed phase nanocrystalline titania exhibit superior photocatalytic activity.

  17. Ultra-high-stability, pH-resistant sol-gel titania poly(tetrahydrofuran) coating for capillary microextraction on-line coupled to high-performance liquid chromatography.

    PubMed

    Segro, Scott S; Cabezas, Yaniel; Malik, Abdul

    2009-05-15

    A sol-gel titania poly(tetrahydrofuran) (poly-THF) coating was developed for capillary microextraction hyphenated on-line with high-performance liquid chromatography (HPLC). Poly-THF was covalently bonded to the sol-gel titania network which, in turn, became chemically anchored to the inner surface of a 0.25mm I.D. fused silica capillary. For sample preconcentration, a 38-cm segment of the sol-gel titania poly-THF coated capillary was installed on an HPLC injection port as a sampling loop. Aqueous samples containing a variety of analytes were passed through the capillary and, during this process, the analytes were extracted by the sol-gel titania poly-THF coating on the inner surface of the capillary. Using isocratic and gradient elution with acetonitrile/water mobile phases, the extracted analytes were desorbed into the on-line coupled HPLC column for separation and UV detection. The sol-gel titania poly-THF coating was especially efficient in extracting polar analytes, such as underivatized phenols, alcohols, amines, and aromatic carboxylic acids. In addition, this coating was capable of extracting moderately polar and nonpolar analytes, such as ketones and polycyclic aromatic hydrocarbons. The sol-gel titania poly-THF coated capillary was also able to extract polypeptides at pH values near their respective isoelectric points. Extraction of these compounds can be important for environmental and biomedical applications. The observed extraction behavior can be attributed to the polar and nonpolar moieties in the poly-THF structure. This coating was found to be stable under extremely low and high pH conditions-even after 18h of exposure to 1M HCl (pH approximately 0.0) and 1M NaOH (pH approximately 14.0).

  18. Titania nanotube arrays as potential interfaces for neurological prostheses

    NASA Astrophysics Data System (ADS)

    Sorkin, Jonathan Andrew

    Neural prostheses can make a dramatic improvement for those suffering from visual and auditory, cognitive, and motor control disabilities, allowing them regained functionality by the use of stimulating or recording electrical signaling. However, the longevity of these devices is limited due to the neural tissue response to the implanted device. In response to the implant penetrating the blood brain barrier and causing trauma to the tissue, the body forms a to scar to isolate the implant in order to protect the nearby tissue. The scar tissue is a result of reactive gliosis and produces an insulated sheath, encapsulating the implant. The glial sheath limits the stimulating or recording capabilities of the implant, reducing its effectiveness over the long term. A favorable interaction with this tissue would be the direct adhesion of neurons onto the contacts of the implant, and the prevention of glial encapsulation. With direct neuronal adhesion the effectiveness and longevity of the device would be significantly improved. Titania nanotube arrays, fabricated using electrochemical anodization, provide a conductive architecture capable of altering cellular response. This work focuses on the fabrication of different titania nanotube array architectures to determine how their structures and properties influence the response of neural tissue, modeled using the C17.2 murine neural stem cell subclone, and if glial encapsulation can be reduced while neuronal adhesion is promoted.

  19. Synthesis of nano-sized ZnO particles by co-precipitation method with variation of heating time

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Purwaningsih, S. Y., E-mail: sriyanisaputri@gmail.com; Pratapa, S.; Triwikantoro

    Zinc oxide powders have been synthesized by a co-precipitation method at low temperature (85 °C), using zinc acetate dihydrate, ammonia, hydrochloric acid solutions as the reactants. A number of process parameters such as reaction temperature, solution basicity or pH and heating time are the main factors affecting the morphology and physical properties of the ZnO nanostructures. In this work the effect of heating time on the morphology and particles size were studied. The as-synthesized ZnO powders were characterized using transmission electron microscopy (TEM) and X-ray diffraction (XRD) techniques. The samples were also analyzed using Fourier transform infrared (FTIR). Rietveld refinementmore » of XRD data confirms that ZnO crystallizes in the hexagonal wurtzite structure with high degree of purity and the (101) plane predominant. The XRD results show that the average crystallite sizes were about 66, 27 and 12 nm for 3, 4 and 5 h of heating times, respectively. The XRD analysis indicated that a fraction of nano-sized ZnO powders were in the form of aggregates, which was also verified by TEM image. The TEM photograph demonstrated that the nano-sized ZnO particles were a pseudo-spherical shape.« less

  20. Atomic-level study on mechanical properties and strengthening mechanisms of Al/SiC nano-composites

    NASA Astrophysics Data System (ADS)

    Huo, Shiyan; Xie, Lijing; Xiang, Junfeng; Pang, Siqin; Hu, Fang; Umer, Usama

    2018-02-01

    Molecular dynamics (MD) models for the study on the mechanical properties of β-SiC particles-reinforced aluminum matrix nano-composites (Al/SiC nano-composites) are established. The nano-composites in the model are fabricated by a powder metallurgy (P/M) process, followed by a hot isostatic pressing and then annealing to room temperature. The fabricated nano-composites have dense and even distributions of reinforced particles. Then representative volume elements (RVEs) of the fabricated nano-composites are built by adding periodic boundary conditions (PBCs). In this way, RVEs with different volume fractions and particle sizes of SiC are produced and put into the simulation of tension tests. The elasticity and strength in single axial tension obtained from MD analysis are in good agreement with those calculated according to the rule of mixture. It is found that the dispersion of SiC particles into the Al matrix leads to a significant enhancement in the strength of nano-composites compared to pure Al, which is also dramatically affected by both the volume fraction and particle size. Additionally, the Al/SiC nano-composites with finer SiC particles get greater enhancement in the mechanical behavior than those with coarser ones. MD analysis clearly shows the contributions of load-transfer effect, thermal mismatch strengthening and Orowan strengthening to the strengthening of Al/SiC nano-composites.

  1. Nano-lithographically fabricated titanium dioxide based visible frequency three dimensional gap photonic crystal.

    PubMed

    Subramania, Ganapathi; Lee, Yun-Ju; Brener, Igal; Luk, Ting-Shan; Clem, Paul G

    2007-10-01

    Photonic crystals (PC) have emerged as important types of structures for light manipulation. Ultimate control of light is possible by creating PCs with a complete three dimensional (3D) gap [1, 2]. This has proven to be a considerable challenge in the visible and ultraviolet frequencies mainly due to complications in integrating transparent, high refractive index (n) materials with fabrication techniques to create ~ 100nm features with long range translational order. In this letter, we demonstrate a nano-lithography approach based on a multilevel electron beam direct write and physical vapor deposition, to fabricate four-layer titania woodpile PCs that potentially exhibit complete 3D gap at visible wavelengths. We achieved a short wavelength bandedge of 525nm with a 300nm lattice constant PC. Due to the nanoscale precision and capability for defect control, the nanolithography approach represents an important step toward novel visible photonic devices for lighting, lasers, sensing and biophotonics.

  2. Photocatalytic performance of crystalline titania polymorphs in the degradation of hazardous pharmaceuticals and dyes

    NASA Astrophysics Data System (ADS)

    Thuong Huyen Tran, Thi; Kosslick, Hendrik; Schulz, Axel; Liem Nguyen, Quang

    2017-03-01

    In the present work, nano-sized TiO2 polymorphs (anatase, brookite, and rutile) were synthesized via hydrothermal treatment of an amorphous titania. Three polymorphs were characterized by XRD, Raman spectroscopy, SEM, UV-Vis DRS, and N2-sorption measurements. The photocatalytic degradation experiments were performed with low catalyst concentration, high organic loading under a 60 W UV-Vis solarium lamp irradiation. The photocatalytic degradation was monitored by UV-Vis spectroscopy and TOC measurements. Cinnamic acid, ibuprofen, phenol, diatrizoic acid and the dyes rhodamine B and rose bengal were used as model pollutants. The formation of intermediates was studied by ESI-TOF-MS measurements. The presence of active species was checked by quenching the activity by addition of scavengers. The photocatalytic activity decreased in the order: anatase  ⩾  brookite  >  rutile, with growing recalcitrance of organic compounds. The differences in the activity are more pronounced in the degree of mineralization. The valence band holes and superoxide radicals were the major active species in the photocatalytic treatment with anatase and brookite, whereas hydroxyl radicals and superoxide radicals contributed mainly in the treatment with rutile explaining the lower activity of rutile. The complementary use of UV-Vis spectroscopy and TOC measurements was required to obtain a comprehensive realistic assessment on the photocatalytic performance of catalyst. Invited talk at 8th International Workshop on Advanced Materials Science and Nanotechnology (IWAMSN2016), 8-12 November 2016, Ha Long City, Vietnam.

  3. Incorporating poly(3-hexyl thiophene) into orthogonally aligned cylindrical nanopores of titania for optoelectronics

    DOE PAGES

    Nagpure, Suraj; Browning, James F.; Rankin, Stephen E.

    2016-11-03

    Here, the incorporation of hole conducting polymer poly(3-hexyl thiophene) (P3HT) into the 8-9 nm cylindrical nanopores of titania is investigated using films with a unique orthogonally oriented hexagonal close packed mesostructure. The films are synthesized using evaporation induced self-assembly (EISA) with Pluronic triblock copolymer F127 as the structure directing agent. The orthogonally oriented cylindrical nanopore structure was chosen over a cubic structure because confinement in uniform cylindrical channels is hypothesized to enhance hole conductivity of P3HT by inducing local polymer chain ordering. Orthogonal orientation of the cylindrical nanopores is achieved by modifying the substrate (FTO-coated glass slides) with crosslinked F127.more » After thermal treatment to remove organic templates from the films, P3HT is infiltrated into the nanopores by spin coating a 1 wt% P3HT solution in chlorobenzene onto the titania films followed by thermal annealing under vacuum at 200 °C. The results show that infiltration is essentially complete after 30 minutes of annealing, with little or no further infiltration thereafter. A final infiltration depth of ~14 nm is measured for P3HT into the nanopores of titania using neutron reflectometry measurements. Photoluminescence measurements demonstrate that charge transfer at the P3HT-TiO 2 interface improves as the P3HT is infiltrated into the pores, suggesting that an active organic-inorganic heterojuction is formed in the materials.« less

  4. Incorporating poly(3-hexyl thiophene) into orthogonally aligned cylindrical nanopores of titania for optoelectronics

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Nagpure, Suraj; Browning, James F.; Rankin, Stephen E.

    Here, the incorporation of hole conducting polymer poly(3-hexyl thiophene) (P3HT) into the 8-9 nm cylindrical nanopores of titania is investigated using films with a unique orthogonally oriented hexagonal close packed mesostructure. The films are synthesized using evaporation induced self-assembly (EISA) with Pluronic triblock copolymer F127 as the structure directing agent. The orthogonally oriented cylindrical nanopore structure was chosen over a cubic structure because confinement in uniform cylindrical channels is hypothesized to enhance hole conductivity of P3HT by inducing local polymer chain ordering. Orthogonal orientation of the cylindrical nanopores is achieved by modifying the substrate (FTO-coated glass slides) with crosslinked F127.more » After thermal treatment to remove organic templates from the films, P3HT is infiltrated into the nanopores by spin coating a 1 wt% P3HT solution in chlorobenzene onto the titania films followed by thermal annealing under vacuum at 200 °C. The results show that infiltration is essentially complete after 30 minutes of annealing, with little or no further infiltration thereafter. A final infiltration depth of ~14 nm is measured for P3HT into the nanopores of titania using neutron reflectometry measurements. Photoluminescence measurements demonstrate that charge transfer at the P3HT-TiO 2 interface improves as the P3HT is infiltrated into the pores, suggesting that an active organic-inorganic heterojuction is formed in the materials.« less

  5. Fabrication of metal matrix composites by powder metallurgy: A review

    NASA Astrophysics Data System (ADS)

    Manohar, Guttikonda; Dey, Abhijit; Pandey, K. M.; Maity, S. R.

    2018-04-01

    Now a day's metal matrix components are used in may industries and it finds the applications in many fields so, to make it as better performable materials. So, the need to increase the mechanical properties of the composites is there. As seen from previous studies major problem faced by the MMC's are wetting, interface bonding between reinforcement and matrix material while they are prepared by conventional methods like stir casting, squeeze casting and other techniques which uses liquid molten metals. So many researchers adopt PM to eliminate these defects and to increase the mechanical properties of the composites. Powder metallurgy is one of the better ways to prepare composites and Nano composites. And the major problem faced by the conventional methods are uniform distribution of the reinforcement particles in the matrix alloy, many researchers tried to homogeneously dispersion of reinforcements in matrix but they find it difficult through conventional methods, among all they find ultrasonic dispersion is efficient. This review article is mainly concentrated on importance of powder metallurgy in homogeneous distribution of reinforcement in matrix by ball milling or mechanical milling and how powder metallurgy improves the mechanical properties of the composites.

  6. Nano-Crystalline Thermally Evaporated Bi2Se3 Thin Films Synthesized from Mechanically Milled Powder

    NASA Astrophysics Data System (ADS)

    Amara, A.; Abdennouri, N.; Drici, A.; Abdelkader, D.; Bououdina, M.; Chaffar Akkari, F.; Khemiri, N.; Kanzari, M.; Bernède, J. C.

    2017-08-01

    Bi2Se3 powder has been successfully synthesized via mechanical ball milling of bismuth and selenium as starting materials. X-ray diffraction characterization revealed the formation of the rhombohedral and orthorhombic phases of Bi2Se3 material belonging to systems with space groups R\\bar{3}m and Pbnm, respectively. The advantageous last finding is confirmed by the Rietveld refinement of the x-ray diffraction data. Furthermore, the analysis of the x-ray data of thermally deposited thin films revealed that both orthorhombic and rhombohedral phases are coexisting in the layer. The morphology of the ball milled powder was studied by scanning electron microscopy. The phase formation of the material is confirmed by Raman spectroscopy. M-H (Magnetization versus Magnetic field) curve indicates that Bi2Se3 powder has a ferromagnetic behavior. Additionally, absorbance and transmittance measurements were carried out on the obtained thermally evaporated thin films and yielded a band gap of 1.33 eV supporting the potential application of the heterogeneous rhombohedral/orthorhombic Bi2Se3 material in photovoltaics.

  7. Chitosan-Based Nano-Embedded Microparticles: Impact of Nanogel Composition on Physicochemical Properties

    PubMed Central

    Islam, Paromita; Water, Jorrit J.; Bohr, Adam; Rantanen, Jukka

    2016-01-01

    Chitosan-based nanogels have been widely applied as drug delivery vehicles. Spray-drying of said nanogels allows for the preparation of dry powder nano-embedded microparticles. In this work, chitosan-based nanogels composed of chitosan, alginate, and/or sodium tri-penta phosphate were investigated, particularly with respect to the impact of composition on the resulting physicochemical properties. Different compositions were obtained as nanogels with sizes ranging from 203 to 561 nm. The addition of alginate and exclusion of sodium tri-penta phosphate led to an increase in nanogel size. The nanogels were subsequently spray-dried to form nano-embedded microparticles with trehalose or mannitol as matrix excipient. The microparticles of different composition were mostly spherical with a smooth surface and a mass median aerodynamic diameter of 6–10 µm. Superior redispersibility was observed for microparticles containing amorphous trehalose. This study demonstrates the potential of nano-embedded microparticles for stabilization and delivery of nanogel-based delivery systems. PMID:28025505

  8. Chitosan-Based Nano-Embedded Microparticles: Impact of Nanogel Composition on Physicochemical Properties.

    PubMed

    Islam, Paromita; Water, Jorrit J; Bohr, Adam; Rantanen, Jukka

    2016-12-22

    Chitosan-based nanogels have been widely applied as drug delivery vehicles. Spray-drying of said nanogels allows for the preparation of dry powder nano-embedded microparticles. In this work, chitosan-based nanogels composed of chitosan, alginate, and/or sodium tri-penta phosphate were investigated, particularly with respect to the impact of composition on the resulting physicochemical properties. Different compositions were obtained as nanogels with sizes ranging from 203 to 561 nm. The addition of alginate and exclusion of sodium tri-penta phosphate led to an increase in nanogel size. The nanogels were subsequently spray-dried to form nano-embedded microparticles with trehalose or mannitol as matrix excipient. The microparticles of different composition were mostly spherical with a smooth surface and a mass median aerodynamic diameter of 6-10 µm. Superior redispersibility was observed for microparticles containing amorphous trehalose. This study demonstrates the potential of nano-embedded microparticles for stabilization and delivery of nanogel-based delivery systems.

  9. Preparation of Si nano-crystals with controlled oxidation state from SiO disproportionated by ZrO2 ball-milling

    NASA Astrophysics Data System (ADS)

    Okamoto, Yuji; Harada, Yoshitomo; Ohta, Narumi; Takada, Kazunori; Sumiya, Masatomo

    2016-09-01

    We demonstrate that a SiO disproportionation reaction can be achieved simply by high energy mechanochemical milling. The planetary ball-milling of ZrO2 for a few minutes generated Si nano-crystals. Milling conditions including rotation speed, ball number, milling time, and type of ball material were able to control the oxidation states of Si. The ball-milled SiO powder was tested as an anode of a lithium battery. ZrO2 contamination from the vial and balls was eliminated by dipping the ball-milled SiO powder in (NH4)HSO4 molten salt and heating for 5 min. The disproportionated SiO powder showed characteristics comparable to those of a powder prepared by a conventional heating process taking several hours.

  10. Effects of fabrication methods on spin relaxation and crystallite quality in Tm-doped ? powders studied using spectral hole burning

    NASA Astrophysics Data System (ADS)

    Lutz, Thomas; Veissier, Lucile; Thiel, Charles W.; Woodburn, Philip J. T.; Cone, Rufus L.; Barclay, Paul E.; Tittel, Wolfgang

    2016-01-01

    High-quality rare-earth-ion (REI) doped materials are a prerequisite for many applications such as quantum memories, ultra-high-resolution optical spectrum analyzers and information processing. Compared to bulk materials, REI doped powders offer low-cost fabrication and a greater range of accessible material systems. Here we show that crystal properties, such as nuclear spin lifetime, are strongly affected by mechanical treatment, and that spectral hole burning can serve as a sensitive method to characterize the quality of REI doped powders. We focus on the specific case of thulium doped ? (Tm:YAG). Different methods for obtaining the powders are compared and the influence of annealing on the spectroscopic quality of powders is investigated on a few examples. We conclude that annealing can reverse some detrimental effects of powder fabrication and, in certain cases, the properties of the bulk material can be reached. Our results may be applicable to other impurities and other crystals, including color centers in nano-structured diamond.

  11. Effect of Nano-SiO₂ on the Hydration and Microstructure of Portland Cement.

    PubMed

    Wang, Liguo; Zheng, Dapeng; Zhang, Shupeng; Cui, Hongzhi; Li, Dongxu

    2016-12-15

    This paper systematically studied the modification of cement-based materials by nano-SiO₂ particles with an average diameter of about 20 nm. In order to obtain the effect of nano-SiO₂ particles on the mechanical properties, hydration, and pore structure of cement-based materials, adding 1%, 3%, and 5% content of nano-SiO₂ in cement paste, respectively. The results showed that the reaction of nano-SiO₂ particles with Ca(OH)₂ (crystal powder) started within 1 h, and formed C-S-H gel. The reaction speed was faster after aging for three days. The mechanical properties of cement-based materials were improved with the addition of 3% nano-SiO₂, and the early strength enhancement of test pieces was obvious. Three-day compressive strength increased 33.2%, and 28-day compressive strength increased 18.5%. The exothermic peak of hydration heat of cement increased significantly after the addition of nano-SiO₂. Appearance time of the exothermic peak was advanced and the total heat release increased. Thermogravimetric-differential scanning calorimetry (TG-DSC) analysis showed that nano-SiO₂ promoted the formation of C-S-H gel. The results of mercury intrusion porosimetry (MIP) showed that the total porosity of cement paste with 3% nano-SiO₂ was reduced by 5.51% and 5.4% at three days and 28 days, respectively, compared with the pure cement paste. At the same time, the pore structure of cement paste was optimized, and much-detrimental pores and detrimental pores decreased, while less harmful pores and innocuous pores increased.

  12. Synthesis and Characterization of Nano Boron Nitride Reinforced Magnesium Composites Produced by the Microwave Sintering Method

    PubMed Central

    Seetharaman, Sankaranarayanan; Subramanian, Jayalakshmi; Tun, Khin Sandar; Hamouda, Abdelmagid S.; Gupta, Manoj

    2013-01-01

    In this study, magnesium composites with nano-size boron nitride (BN) particulates of varying contents were synthesized using the powder metallurgy (PM) technique incorporating microwave-assisted two-directional sintering followed by hot extrusion. The effect of nano-BN addition on the microstructural and the mechanical behavior of the developed Mg/BN composites were studied in comparison with pure Mg using the structure-property correlation. Microstructural characterization revealed uniform distribution of nano-BN particulates and marginal grain refinement. The coefficient of thermal expansion (CTE) value of the magnesium matrix was improved with the addition of nano-sized BN particulates. The results of XRD studies indicate basal texture weakening with an increase in nano-BN addition. The composites showed improved mechanical properties measured under micro-indentation, tension and compression loading. While the tensile yield strength improvement was marginal, a significant increase in compressive yield strength was observed. This resulted in the reduction of tension-compression yield asymmetry and can be attributed to the weakening of the strong basal texture. PMID:28809252

  13. Nano-scaled top-down of bismuth chalcogenides based on electrochemical lithium intercalation

    NASA Astrophysics Data System (ADS)

    Chen, Jikun; Zhu, Yingjie; Chen, Nuofu; Liu, Xinling; Sun, Zhengliang; Huang, Zhenghong; Kang, Feiyu; Gao, Qiuming; Jiang, Jun; Chen, Lidong

    2011-12-01

    A two-step method has been used to fabricate nano-particles of layer-structured bismuth chalcogenide compounds, including Bi2Te3, Bi2Se3, and Bi2Se0.3Te2.7, through a nano-scaled top-down route. In the first step, lithium (Li) atoms are intercalated between the van der Waals bonded quintuple layers of bismuth chalcogenide compounds by controllable electrochemical process inside self-designed lithium ion batteries. And in the second step, the Li intercalated bismuth chalcogenides are subsequently exposed to ethanol, in which process the intercalated Li atoms would explode like atom-scaled bombs to exfoliate original microscaled powder into nano-scaled particles with size around 10 nm. The influence of lithium intercalation speed and amount to three types of bismuth chalcogenide compounds are compared and the optimized intercalation conditions are explored. As to maintain the phase purity of the final nano-particle product, the intercalation lithium amount should be well controlled in Se contained bismuth chalcogenide compounds. Besides, compared with binary bismuth chalcogenide compound, lower lithium intercalation speed should be applied in ternary bismuth chalcogenide compound.

  14. HOT ELUENT CAPILLARY LIQUID CHROMATOGRAPHY USING ZIRCONIA AND TITANIA BASED STATIONARY PHASES. (R825344)

    EPA Science Inventory

    Abstract

    High speed capillary liquid chromatographic separations using a simple home made system constructed from readily available inexpensive components have been studied. Using thermally stable zirconia and titania based packing, the separation of eight alkylbenzene...

  15. Mechanical behavior of shock-wave consolidated nano and micron-sized aluminum/silicon carbide and aluminum/aluminum oxide two-phase systems characterized by light and electron metallography

    NASA Astrophysics Data System (ADS)

    Alba-Baena, Noe Gaudencio

    This dissertation reports the results of the exploratory study of two-phase systems consisting of 150 microm diameter aluminum powder mechanically mixed with 30 nm and 30 microm diameter SiC and Al2O3 powders (in volume fractions of 2, 4, and 21 percent). Powders were mechanically mixed and green compacted to ˜80% theorical density in a series of cylindrical fixtures (steel tubes). The compacted arrangements were explosively consolidated using ammonium nitrate-fuel oil (ANFO) to form stacks of two-phase systems. As result, successfully consolidated cylindrical monoliths of 50 mm (height) x 32 mm (in diameter) were obtained. By taking advantage of the use of SWC (shock wave consolidation) and WEDM (wire-electric discharge machining), the heterogeneous systems were machined in a highly efficiency rate. The sample cuts used for characterization and mechanical properties testing, require the use of less that 10cc of each monolith, in consequence there was preserved an average of 60% of the obtained system monoliths. Consolidated test cylinders of the pure Al and two-phase composites were characterized by optical metallography and TEM. The light micrographs for the five explosively consolidated regimes: aluminum powder, nano and micron-sized Al/Al2O3 systems, and the nano and micron-sized Al/SiC systems exhibit similar ductility in the aluminum grains. Low volume fraction systems exhibit small agglomerations at the grain boundaries for the Al/Al2O3 system and the Al/SiC system reveal a well distributed phase at the grain boundaries. Large and partially bonded agglomerations were observable in the nano-sized high volume fraction (21%) systems, while the micron-sized Al/ceramic systems exhibit homogeneous distribution along the aluminum phase grains. TEM images showed the shock-induced dislocation cell structure, which has partially recrystallized to form a nano grain structure in the consolidated aluminum powder. Furthermore, the SiC nano-agglomerates appeared to have

  16. Corona-assisted flame synthesis of ultrafine titania particles

    NASA Astrophysics Data System (ADS)

    Vemury, Srinivas; Pratsinis, Sotiris E.

    1995-06-01

    Synthesis of ultrafine titania particles is investigated in a diffusion flame aerosol reactor in the presence of a gaseous electric discharge (corona) created by two needle electrodes. The corona wind flattens the flame and reduces the particle residence time at high temperatures, resulting in smaller primary particle sizes and lower level of crystallinity. Increasing the applied potential from 5 to 8 kV reduces the particle size from 50 to 25 nm and the rutile content from 20 to 8 wt %. Coronas provide a clean and simple technique that facilitates gas phase synthesis of nanosized materials with controlled size and crystallinity.

  17. Effect of hot water and heat treatment on the apatite-forming ability of titania films formed on titanium metal via anodic oxidation in acetic acid solutions.

    PubMed

    Cui, Xinyu; Kim, Hyun-Min; Kawashita, Masakazu; Wang, Longbao; Xiong, Tianying; Kokubo, Tadashi; Nakamura, Takashi

    2008-04-01

    Titanium and its alloys have been widely used for orthopedic implants because of their good biocompatibility. We have previously shown that the crystalline titania layers formed on the surface of titanium metal via anodic oxidation can induce apatite formation in simulated body fluid, whereas amorphous titania layers do not possess apatite-forming ability. In this study, hot water and heat treatments were applied to transform the titania layers from an amorphous structure into a crystalline structure after titanium metal had been anodized in acetic acid solution. The apatite-forming ability of titania layers subjected to the above treatments in simulated body fluid was investigated. The XRD and SEM results indicated hot water and/or heat treatment could greatly transform the crystal structure of titania layers from an amorphous structure into anatase, or a mixture of anatase and rutile. The abundance of Ti-OH groups formed by hot water treatment could contribute to apatite formation on the surface of titanium metals, and subsequent heat treatment would enhance the bond strength between the apatite layers and the titanium substrates. Thus, bioactive titanium metals could be prepared via anodic oxidation and subsequent hot water and heat treatment that would be suitable for applications under load-bearing conditions.

  18. Modifications in Glass Ionomer Cements: Nano-Sized Fillers and Bioactive Nanoceramics

    PubMed Central

    Najeeb, Shariq; Khurshid, Zohaib; Zafar, Muhammad Sohail; Khan, Abdul Samad; Zohaib, Sana; Martí, Juan Manuel Nuñez; Sauro, Salvatore; Matinlinna, Jukka Pekka; Rehman, Ihtesham Ur

    2016-01-01

    Glass ionomer cements (GICs) are being used for a wide range of applications in dentistry. In order to overcome the poor mechanical properties of glass ionomers, several modifications have been introduced to the conventional GICs. Nanotechnology involves the use of systems, modifications or materials the size of which is in the range of 1–100 nm. Nano-modification of conventional GICs and resin modified GICs (RMGICs) can be achieved by incorporation of nano-sized fillers to RMGICs, reducing the size of the glass particles, and introducing nano-sized bioceramics to the glass powder. Studies suggest that the commercially available nano-filled RMGIC does not hold any significant advantage over conventional RMGICs as far as the mechanical and bonding properties are concerned. Conversely, incorporation of nano-sized apatite crystals not only increases the mechanical properties of conventional GICs, but also can enhance fluoride release and bioactivity. By increasing the crystallinity of the set matrix, apatites can make the set cement chemically more stable, insoluble, and improve the bond strength with tooth structure. Increased fluoride release can also reduce and arrest secondary caries. However, due to a lack of long-term clinical studies, the use of nano-modified glass ionomers is still limited in daily clinical dentistry. In addition to the in vitro and in vivo studies, more randomized clinical trials are required to justify the use of these promising materials. The aim of this paper is to review the modification performed in GIC-based materials to improve their physicochemical properties. PMID:27428956

  19. Emission-photoactivity cross-processing of mesoporous interfacial charge transfer in Eu3+ doped titania.

    PubMed

    Leroy, Céline Marie; Wang, Hong Feng; Fargues, Alexandre; Cardinal, Thierry; Jubera, Véronique; Treguer-Delapierre, Mona; Boissière, Cédric; Grosso, David; Sanchez, Clément; Viana, Bruno; Pellé, Fabienne

    2011-07-07

    Periodic mesoporous Eu(3+) doped titania materials were obtained through the EISA (Evaporation Induced Self Assembly) process. Eu(3+) ions, entrapped within the semi-crystalline walls of the highly porous framework, appear to be advantageous during the probing of surface photochemical reactions. Its emission intensity is very sensitive to the presence of physisorbed molecules, in gas or liquid phase, that reside within the pores. In particular, strong fluctuations in intensity of the (5)D(0)→(7)F(2) transition were observed under UV light exposure on the time scale of tens of seconds. The emission modulation dynamics show a strong correlation with the crystallinity of the titania matrix. Correlation of the emission with the photocatalytic activity of the semiconductor for photodegradation of an organic molecule is observed. A model is proposed to describe the involved mechanisms. This journal is © the Owner Societies 2011

  20. One-step synthesis of titania nanoparticles from PS-P4VP diblock copolymer solution

    NASA Astrophysics Data System (ADS)

    Song, Lixin; Lam, Yeng Ming; Boothroyd, Chris; Teo, Puat Wen

    2007-04-01

    Polymeric films containing titania nanoparticles have potential as dielectric films for flexible electronic applications. For this purpose, the nanoparticles must be homogeneously distributed. Self-assembly is emerging as a neat, elegant method for fabricating such nanostructured hybrid materials with well-distributed nanoparticles. In this work, we report a micellar solution approach for the assembly of copolymer-titanium precursor nanostructures in which titania nanoparticles were synthesized. The ratio of the amount of titanium precursor, titanium isopropoxide, to the blocks forming the micellar core, poly(4-vinylpyridine), was found to play a key role in controlling film morphology. A sphere-to-ribbon transition was observed when the amount of titanium isopropoxide was increased. The thin film morphology can be tuned using the precursor-copolymer interaction rather than just the polymer-polymer interaction or the polymer-solution interaction. This method provides yet another way to control the morphology of nanostructures.

  1. Study of phase transformation and microstructure of alcohol washed titania nanoparticles for thermal stability

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kaur, Manpreet, E-mail: manpreet.kaur@thapar.edu; Singh, Gaganjot; Bimbraw, Keshav

    Nanostructured titania have been successfully synthesized by hydrolysis of alkoxide at calcination temperatures 500 °C, 600 °C and 700 °C. As the calcination temperature increases, alcohol washed samples show lesser rutile content as compared to water washed samples. Morphology and Particle sizes was determined by field emission scanning electron microscopy (FESEM), while thermogravimetric-differential scanning calorimetry (TG-DSC) was used to determine thermal stability. Alcohol washed samples undergo 30% weight loss whereas 16% in water washed samples was observed. The mean particle sizes were found to be increase from 37 nm to 100.9 nm and 35.3 nm to 55.2 nm for water and alcohol washed samplesmore » respectively. Hydrolysis of alkoxide was shown to be an effective means to prepare thermally stable titania by using alcohol washed samples as a precursor.« less

  2. Rationale for the crystallization of titania polymorphs in solution

    NASA Astrophysics Data System (ADS)

    Kränzlin, N.; Staniuk, M.; Heiligtag, F. J.; Luo, L.; Emerich, H.; van Beek, W.; Niederberger, M.; Koziej, D.

    2014-11-01

    We use in situ X-ray absorption and diffraction studies to directly monitor the crystallization of different titania polymorphs in one and the same solution. We find that, despite the commonly accepted polymorphic-crossover from anatase to rutile triggered by the critical size of nanoparticles, in the solution their respective nucleation and growth are independent processes. Moreover, we find that 5.9 nm rutile nanoparticles are formed prior to the formation of 8.4 nm anatase nanoparticles. Our results suggest that the origins of this crystallization mechanism lie in the formation of an intermediate non-crystalline phase and in time-dependent changes in the chemical environment.We use in situ X-ray absorption and diffraction studies to directly monitor the crystallization of different titania polymorphs in one and the same solution. We find that, despite the commonly accepted polymorphic-crossover from anatase to rutile triggered by the critical size of nanoparticles, in the solution their respective nucleation and growth are independent processes. Moreover, we find that 5.9 nm rutile nanoparticles are formed prior to the formation of 8.4 nm anatase nanoparticles. Our results suggest that the origins of this crystallization mechanism lie in the formation of an intermediate non-crystalline phase and in time-dependent changes in the chemical environment. Electronic supplementary information (ESI) available: Detailed instructions on the experimental part including set-up, recorded XAS and PXRD raw data and their details. See DOI: 10.1039/c4nr04346d

  3. Pore structures in an implantable sol gel titania ceramic device used in controlled drug release applications: A modeling study

    NASA Astrophysics Data System (ADS)

    Peterson, Aaron; Lopez, Tessy; Islas, Emma Ortiz; Gonzalez, Richard D.

    2007-04-01

    Several process variables, which may be helpful in optimizing the rate at which drugs are released from implantable, sol-gel titania devices have been identified in this study. The controlled rate of drug release is compared for two different anticonvulsant drugs, valproic acid and sodic phenytoin. Contrary to what one might expect, when the concentration is increased in the titania reservoir the rate of initial drug delivery decreases. This is a desirable result, because it may reduce the danger of a high initial discharge, which may harm the epileptic rat. The structure of the porous structure within the titania network has been studied using a generalized form of the BET equation which considers only n layers. In general, following an initial discharge, the rate at which the drug is released will increase with the increasing concentration. Pore mouth blocking can present a problem. However, this problem tends to disappear following the initial discharge. The extent of drug loading is a useful variable parameter, which can be adjusted in order to deliver the amount of drug required in a given application.

  4. Nano-Tubular Cellulose for Bioprocess Technology Development

    PubMed Central

    Koutinas, Athanasios A.; Sypsas, Vasilios; Kandylis, Panagiotis; Michelis, Andreas; Bekatorou, Argyro; Kourkoutas, Yiannis; Kordulis, Christos; Lycourghiotis, Alexis; Banat, Ibrahim M.; Nigam, Poonam; Marchant, Roger; Giannouli, Myrsini; Yianoulis, Panagiotis

    2012-01-01

    Delignified cellulosic material has shown a significant promotional effect on the alcoholic fermentation as yeast immobilization support. However, its potential for further biotechnological development is unexploited. This study reports the characterization of this tubular/porous cellulosic material, which was done by SEM, porosimetry and X-ray powder diffractometry. The results showed that the structure of nano-tubular cellulose (NC) justifies its suitability for use in “cold pasteurization” processes and its promoting activity in bioprocessing (fermentation). The last was explained by a glucose pump theory. Also, it was demonstrated that crystallization of viscous invert sugar solutions during freeze drying could not be otherwise achieved unless NC was present. This effect as well as the feasibility of extremely low temperature fermentation are due to reduction of the activation energy, and have facilitated the development of technologies such as wine fermentations at home scale (in a domestic refrigerator). Moreover, NC may lead to new perspectives in research such as the development of new composites, templates for cylindrical nano-particles, etc. PMID:22496794

  5. Aggregate breakdown of nanoparticulate titania

    NASA Astrophysics Data System (ADS)

    Venugopal, Navin

    Six nanosized titanium dioxide powders synthesized from a sulfate process were investigated. The targeted end-use of this powder was for a de-NOx catalyst honeycomb monolith. Alteration of synthesis parameters had resulted principally in differences in soluble ion level and specific surface area of the powders. The goal of this investigation was to understand the role of synthesis parameters in the aggregation behavior of these powders. Investigation via scanning electron microscopy of the powders revealed three different aggregation iterations at specific length scales. Secondary and higher order aggregate strength was investigated via oscillatory stress rheometry as a means of simulating shear conditions encountered during extrusion. G' and G'' were measured as a function of the applied oscillatory stress. Oscillatory rheometry indicated a strong variation as a function of the sulfate level of the particles in the viscoelastic yield strengths. Powder yield stresses ranged from 3.0 Pa to 24.0 Pa of oscillatory stress. Compaction curves to 750 MPa found strong similarities in extrapolated yield point of stage I and II compaction for each of the powders (at approximately 500 MPa) suggesting that the variation in sulfate was greatest above the primary aggregate level. Scanning electron microscopy of samples at different states of shear in oscillatory rheometry confirmed the variation in the linear elastic region and the viscous flow regime. A technique of this investigation was to approach aggregation via a novel perspective: aggregates are distinguished as being loose open structures that are highly disordered and stochastic in nature. The methodology used was to investigate the shear stresses required to rupture the various aggregation stages encountered and investigate the attempt to realign the now free-flowing constituents comprising the aggregate into a denser configuration. Mercury porosimetry was utilized to measure the pore size of the compact resulting from

  6. Colloidal titania-silica-iron oxide nanocomposites and the effect from silica thickness on the photocatalytic and bactericidal activities

    NASA Astrophysics Data System (ADS)

    Chanhom, Padtaraporn; Charoenlap, Nisanart; Tomapatanaget, Boosayarat; Insin, Numpon

    2017-04-01

    New types of colloidal multifunctional nanocomposites that combine superparamagnetic character and high photocatalytic activity were synthesized and investigated. The superparamagnetic nanocomposites composed of anatase titania, silica, and iron oxide nanoparticles (TSI) were synthesized using thermal decomposition method followed by microemulsion method, without calcination at high temperature. Different techniques including X-ray diffraction (XRD) and transmission electron microscope (TEM) were used to characterize and confirm the structure of the nanocomposites. These nanocomposites showed high photocatalytic activity when used in the photodegradation of methylene blue under irradiation with a black light lamp. Moreover, the nanocomposites exhibited high antibacterial properties. From our study, the nanocomposites can be useful in various applications such as removal of pollutants with readily separation from the environment using an external magnetic field. These composites could effectively photo-degrade the dye at least three cycles without regeneration. The effects of silica shell thickness on the photocatalytic activity was investigated, and the thickness of 6 nm of the silica interlayer is enough for the inhibition of electron translocation between titania and iron oxide nanoparticles and maintaining the efficiency of photocatalytic activity of titania nanoparticles.

  7. Sintered magnetic cores of high Bs Fe84.3Si4B8P3Cu0.7 nano-crystalline alloy with a lamellar microstructure

    NASA Astrophysics Data System (ADS)

    Zhang, Yan; Sharma, Parmanand; Makino, Akihiro

    2014-05-01

    Fabrication of bulk cores of nano-crystalline Fe84.3Si4B8P3Cu0.7 alloy with a lamellar type of microstructure is reported. Amorphous ribbon flakes of size ˜1.0-2.0 mm were compacted in the bulk form by spark plasma sintering technique at different sintering temperatures. High density (˜96.4%) cores with a uniform nano-granular structure made from α-Fe (˜31 nm) were obtained. These cores show excellent mechanical and soft magnetic properties. The lamellar micro-structure is shown to be important in achieving significantly lower magnetic core loss than the non-oriented silicon steel sheets, commercial powder cores and even the core made of the same alloy with finer and randomly oriented powder particles.

  8. In-vitro bioactivity and electrochemical behavior of polyaniline encapsulated titania nanotube arrays for biomedical applications

    NASA Astrophysics Data System (ADS)

    Agilan, P.; Rajendran, N.

    2018-05-01

    Titania nanotube arrays (TNTA) have attracted increasing attention due to their outstanding properties and potential applications in biomedical field. Fabrication of titania nanotubes on titanium surface enhances the biocompatibility. Polyaniline (PANI) is one of the best conducting polymers with remarkable corrosion resistance and reasonable biocompatibility. In this work, the corrosion resistance and biocompatibility of polyaniline encapsulated TiO2 nanotubes for orthopaedic applications were investigated. The vertically oriented, highly ordered TiO2 nanotubes were fabricated on titanium by electrochemical anodization process using fluoride containing electrolytes. The anodization parameters viz., voltage, pH, time and electrolyte concentration were optimized to get orderly arranged TNTA. Further, the conducting polymer PANI was encapsulated on TNTA by electropolymerization process to enhance the corrosion resistance. The nanostructure of the fabricated TNTA and polyaniline encapsulated titania nanotube arrays (PANI-TNTA) were investigated by HR SEM analysis. The formed phases and functional groups were find using XRD, ATR-FTIR. The hydrophilic surface of TNTA and PANI-TNTA was identified by water contact angle studies. The corrosion behavior of specimens was evaluated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization studies. In-vitro immersion studies were carried out in simulated body fluid solution (Hanks' solution) to evaluate the bioactivity of the TNTA and PANI-TNTA. The surface morphological studies revealed the formation of PANI on the TNTA surface. Formation of hydroxyapatite (HAp) on the surfaces of TNTA and PANI-TNTA enhanced the bioactivity and corrosion resistance.

  9. Toward compositional design of reticular type porous films by mixing and coating titania-based frameworks with silica

    NASA Astrophysics Data System (ADS)

    Kimura, T.

    2015-12-01

    A recently developed reticular type porous structure, which can be fabricated as the film through the soft colloidal block copolymer (e.g., PS-b-PEO) templating, is very promising as the porous platform showing high-performance based on its high surface area as well as high diffusivity of targeted organic molecules and effective accommodation of bulky molecules, but the compositional design of oxide frameworks has not been developed so enough to date. Here, I report reliable synthetic methods of the reticular type porous structure toward simple compositional variations. Due to the reproducibility of reticular type porous titania films from titanium alkoxide (e.g., TTIP; titanium tetraisopropoxide), a titania-silica film having similar porous structure was obtained by mixing silicon alkoxide (e.g., tetraethoxysilane) and TTIP followed by their pre-hydrolysis, and the mixing ratio of Ti to Si composition was easily reached to 1.0. For further compositional design, a concept of surface coating was widely applicable; the reticular type porous titania surfaces can be coated with other oxides such as silica. Here, a silica coating was successfully achieved by the simple chemical vapor deposition of silicon alkoxide (e.g., tetramethoxysilane) without water (with water at the humidity level), which was also utilized for pore filling with silica by the similar process with water.

  10. Modifying Si-based consolidants through the addition of colloidal nano-particles

    NASA Astrophysics Data System (ADS)

    Ksinopoulou, E.; Bakolas, A.; Moropoulou, A.

    2016-04-01

    The modification of silicon-based stone consolidants has been the subject of many scientific studies aiming to overcome the commonly reported drawbacks of these materials, such as the tendency to shrink and crack during drying. The addition of nano-particle dispersions into silica matrix has been found to enhance their effectiveness in several ways. Objective of the current research was to study the preparation of particle-modified consolidants (PMC), consisting of an ethyl silicate matrix (TEOS) loaded with colloidal silica (SiO2) nano-particles and oxide titania (TiO2) particles. The effect of the polyacrylic acid on the dispersion stability was also investigated, by varying its concentration into PMC samples. The prepared materials were allowed to dry in two different relative humidity environments and then evaluated based on their stability in the sol phase, the aggregation sizes, determined through dynamic light scattering, the % solids content and their morphological characteristics, observed via scanning electron microscopy (SEM-EDAX). Mercury intrusion porosimetry was also applied to investigate the microstructural characteristics and differences between the prepared consolidants. Significant role in the final form of the material is played by both the initial molar ratios in the mixtures, as well as the conditions where the drying and aging takes place. Based on the results, the three-component PMCs appear to be promising in stone consolidation, as they show a reduction in cracking and shrinkage during drying and a more porous network, compared with the siliceous material, or the two-component TEOS-SiO2 formulation.

  11. Controlling the sol–gel process of nano-crystalline lithium-mica glass-ceramic by its chemical composition and synthesis parameters

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tohidifar, M.R., E-mail: tohidifar@znu.ac.ir; Alizadeh, P.; Aghaei, A.R.

    2015-01-15

    This paper aims to explore the impact of the parameters such as pH of the system, refluxing temperature, water quantity and chemical composition on the sol–gel synthesis of lithium-mica glass-ceramic nano-powder. The synthesis process was accomplished using two chemical composition formula (Li{sub (1+x)}Mg{sub 3}AlSi{sub 3(1+x)}O{sub 10+6.5x}F{sub 2} and LiMg{sub 3}AlSi{sub 3(1+x)}O{sub 10+6x}F{sub 2}). X-ray diffraction, Brunauer–Emmett–Teller surface area measurement and scanning electron microscopy techniques were applied to evaluate a variety of as-synthesized samples. Consequently, a transparent homogeneous sol was obtained under the conditions as pH ≤ 4, synthesis temperature ≤ 50 °C, and mol ratio of water to chemicals ≤more » 2. The prepared nano-powders under such conditions were in the range of 60–100 nm. The results also revealed that the mica glass-ceramics prepared based on the composition Li{sub (1+x)}Mg{sub 3}AlSi{sub 3(1+x)}O{sub 10+6.5x}F{sub 2} possessed finer powders due to their slow hydrolysis process. Moreover, any reduction in the stoichiometric deviation of lithium mica (x) leads to acquiring finer powders. - Highlights: • A transparent homogeneous sol leads to prepare nanopowders in the range of 60–100 nm. • The particles synthesized at lower temperatures possess finer sizes. • The acquired product which is prepared with excessive water offers larger sizes. • Any reduction in stoichiometric deviation leads to acquiring finer powders. • Taking synthesis composition as Li{sub (1+x)}Mg{sub 3}AlSi{sub 3(1+x)}O{sub 10+6.5x}F{sub 2} offers finer powders.« less

  12. Negative results of growing titania nanotubes on cellulose nanocrystals - Effect of hydrothermal reaction

    NASA Astrophysics Data System (ADS)

    Chamakh, Mariem Mohamed; Ponnamma, Deepalekshmi; Al-Maadeed, Mariam Al Ali

    Titania nanotubes (TiO2 nanotubes or TNT) are grown hydrothermally on cellulose nanocrystals (CNC) synthesized from microcrystalline cellulose. It is observed that the CNC are lost during synthesis due to its low thermal stability. This negative result of metal growth on CNC and its influence on thermal degradation are reported here.

  13. Stability of hepatoprotecting agent IFC-305 encapsulated into sol-gel titania nanoparticles and drug release evaluation: water and drug concentration effect.

    PubMed

    Albarran, L; López, T; Quintana, P; Chagoya, V

    2012-03-01

    IFC-305 was encapsulated into nanostructured titania and functionalized with OH groups by the sol-gel process using titanium n-butoxide, to be used in a drug delivery system for the treatment of liver cancer. Synthesis was carried out at different molar hydrolysis ratios: 4, 8, 16 and 24 mol of water; and drug concentration of 10, 20 and 30%. Characterization of IFC-titania reservoirs was carried out by Fourier transformed infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermal analysis (DTA-TGA), scanning electron microscopy (SEM), and N2 adsorption-desorption isotherms (BET), confirms that IFC-305 is entrapped and stabilized in the TiO2-OH matrix. Drug liberation in vitro was determined by UV spectrometry over a period of 1000 h. This study demonstrated that the higher water content and the higher amount of loaded IFC, favored hydrogen bonding between titania-OH surface and IFC-NH groups, increasing the rate of drug release.

  14. Fabrication of nano-Fe3O4 3D structure on carbon fibers as a microwave absorber and EMI shielding composite by modified EPD method

    NASA Astrophysics Data System (ADS)

    Gholampoor, Mahdi; Movassagh-Alanagh, Farid; Salimkhani, Hamed

    2017-02-01

    Recently, electromagnetic interference (EMI) shielding materials have absorbed a lot of attention due to a growing need for application in the area of electronic and wireless devices. In this study, a carbon-based EMI shielding composite was fabricated by electrophoretic deposition of Fe3O4 nano-particles on carbon fibers (CFs) as a 3D structure incorporated with an epoxy resin. Co-precipitation method was employed to synthesize Fe3O4 nano-particles. This as-synthesized Fe3O4 nano-powder was then successfully deposited on CFs using a modified multi-step electrophoretic deposition (EPD) method. The results of structural studies showed that the Fe3O4 nano-particles (25 nm) were successfully and uniformly deposited on CFs. The measured magnetic properties of as-synthesized Fe3O4 nano-powder and nano-Fe3O4/CFs composite showed that the saturation magnetization of bare Fe3O4 was decreased from Ms = 72.3 emu/g to Ms = 33.1 emu/g for nano-Fe3O4/CFs composite and also corecivity of Fe3O4 was increased from Hc = 4.9 Oe to Hc = 168 Oe for composite. The results of microwave absorption tests revealed that the reflection loss (RL) of an epoxy-based nano-Fe3O4/CFs composite are significantly influenced by layer thickness. The maximum RL value of -10.21 dB at 10.12 GHz with an effective absorption bandwidth about 2 GHz was obtained for the sample with the thickness of 2 mm. It also exhibited an EMI shielding performance of -23 dB for whole the frequency range of 8.2-12.4 GHz.

  15. Role of Water and Carbonates in Photocatalytic Transformation of CO2 to CH4 on Titania

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Dimitrijevic, Nada; Vijayan, Baiju K.; Poluektov, Oleg G.

    Using the electron paramagnetic resonance technique, we have elucidated the multiple roles of water and carbonates in the overall photocatalytic reduction of carbon dioxide to methane over titania nanoparticles. The formation of H atoms (reduction product) and {sm_bullet}OH radicals (oxidation product) from water, and CO{sub 3}{sup -} radical anions (oxidation product) from carbonates, was detected in CO{sub 2}-saturated titania aqueous dispersion under UV illumination. Additionally, methoxyl, {sm_bullet}OCH{sub 3}, and methyl, {sm_bullet}CH{sub 3}, radicals were identified as reaction intermediates. The two-electron, one-proton reaction proposed as an initial step in the reduction of CO{sub 2}, on the surface of TiO{sub 2}, ismore » supported by the results of first-principles calculations.« less

  16. Methods for producing monodispersed particles of barium titanate

    DOEpatents

    Hu, Zhong-Cheng

    2001-01-01

    The present invention is a low-temperature controlled method for producing high-quality, ultrafine monodispersed nanocrystalline microsphere powders of barium titanate and other pure or composite oxide materials having particles ranging from nanosized to micronsized particles. The method of the subject invention comprises a two-stage process. The first stage produces high quality monodispersed hydrous titania microsphere particles prepared by homogeneous precipitation via dielectric tuning in alcohol-water mixed solutions of inorganic salts. Titanium tetrachloride is used as an inorganic salt precursor material. The second stage converts the pure hydrous titania microsphere particles into crystalline barium titanate microsphere powders via low-temperature, hydrothermal reactions.

  17. Investigation of the potential for direct compaction of a fine ibuprofen powder dry-coated with magnesium stearate.

    PubMed

    Qu, Li; Zhou, Qi Tony; Gengenbach, Thomas; Denman, John A; Stewart, Peter J; Hapgood, Karen P; Gamlen, Michael; Morton, David A V

    2015-05-01

    Intensive dry powder coating (mechanofusion) with tablet lubricants has previously been shown to give substantial powder flow improvement. This study explores whether the mechanofusion of magnesium stearate (MgSt), on a fine drug powder can substantially improve flow, without preventing the powder from being directly compacted into tablets. A fine ibuprofen powder, which is both cohesive and possesses a low-melting point, was dry coated via mechanofusion with between 0.1% and 5% (w/w) MgSt. Traditional low-shear blending was also employed as a comparison. No significant difference in particle size or shape was measured following mechanofusion. For the low-shear blended powders, only marginal improvement in flowability was obtained. However, after mechanofusion, substantial improvements in the flow properties were demonstrated. Both XPS and ToF-SIMS demonstrated high degrees of a nano-scale coating coverage of MgSt on the particle surfaces from optimized mechanofusion. The study showed that robust tablets were produced from the selected mechanofused powders, at high-dose concentration and tablet tensile strength was further optimized via addition of a Polyvinylpyrrolidone (PVP) binder (10% w/w). The tablets with the mechanofused powder (with or without PVP) also exhibited significantly lower ejection stress than those made of the raw powder, demonstrating good lubrication. Surprisingly, the release rate of drug from the tablets made with the mechanofused powder was not retarded. This is the first study to demonstrate such a single-step dry coating of model drug with MgSt, with promising flow improvement, flow-aid and lubrication effects, tabletability and also non-inhibited dissolution rate.

  18. Structural, morphological, and optical study of titania-based nanopowders suitable for photocatalytic applications

    NASA Astrophysics Data System (ADS)

    Šćepanović, M.; Grujić-Brojčin, M.; Abramović, B.; Golubović, A.

    2017-01-01

    Systematic investigation of the relationship between structural, morphological, optical and photocatalytic properties of the titania-based nanopowders is presented. A series of pure and doped titania catalysts with various (anatase and brookite) phase compositions have been prepared by sol-gel or hydrothermal route. The crystal structure and composition of the synthesized samples have been extensively characterised by XRD and Raman scattering measurements. The nanopowder morphology has been studied using microscopic methods (SEM, AFM, and STM), whereas the porous structure has been revealed by the analysis of nitrogen sorption data. The optical and electronic properties have been studied by spectroscopic ellipsometry. All investigated properties have been correlated to photocatalytic activity, tested in degradation of the pharmaceutically active substances (such as metoprolol and alprazolam) induced by UVA or visible radiation. Based on this correlation, the physical properties which contribute most to the increase in photocatalytic activity of synthesized nanopowders have been determined, in order to optimize the synthesis conditions which could lead to the maximal efficiency in degradation of particular pollutant.

  19. Sulfated Titania-Silica Reinforced Nafion Nanocomposite Membranes for Proton Exchange Membrane Fuel Cells.

    PubMed

    Abu Sayeed, M D; Kim, Hee Jin; Gopalan, A I; Kim, Young Ho; Lee, Kwang-Pill; Choi, Sang-June

    2015-09-01

    Sulfated titania-silica (SO4(2-)-/TiO2-SiO2) composites were prepared by a sol-gel method with sulfate reaction and characterized by X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDS). The nanometric diameter and geometry of the sulfated titania-silica (STS) was investigated by transmission electron microscopy (TEM). A small amount of the STS composite in the range of 0.5-3 wt% was then added as reinforcing into the Nafion membrane by water-assisted solution casting method to prepare STS reinforced Nafion nanocomposite membranes (STS-Nafion nanocomposite membranes). The additional functional groups, sulfate groups, of the nanocomposite membrane having more surface oxygenated groups enhanced the fuel cell membrane properties. The STS-Nafion nanocomposite membranes exhibited improved water uptake compared to that of neat Nafion membranes, whereas methanol uptake values were decreased dramatically improved thermal property of the prepared nanocomposite membranes were measured by thermogravimetric analysis (TGA). Furthermore, increased ion exchange capacity values were obtained by thermoacidic pretreatment of the nanocomposite membranes.

  20. Polyaniline nanowire array encapsulated in titania nanotubes as a superior electrode for supercapacitors

    NASA Astrophysics Data System (ADS)

    Xie, Keyu; Li, Jie; Lai, Yanqing; Zhang, Zhi'an; Liu, Yexiang; Zhang, Guoge; Huang, Haitao

    2011-05-01

    Conducting polymer with 1D nanostructure exhibits excellent electrochemical performances but a poor cyclability that limits its use in supercapacitors. In this work, a novel composite electrode made of polyaniline nanowire-titania nanotube array was synthesized via a simple and inexpensive electrochemical route by electropolymerizing aniline onto an anodized titania nanotube array. The specific capacitance was as high as 732 F g-1 at 1 A g-1, which remained at 543 F g-1 when the current density was increased by 20 times. 74% of the maximum energy density (36.6 Wh kg-1) was maintained even at a high power density of 6000 W kg-1. An excellent long cycle life of the electrode was observed with a retention of ~86% of the initial specific capacitance after 2000 cycles. The good electrochemical performance was attributed to the unique microstructure of the electrode with disordered PANI nanowire arrays encapsulated inside the TiO2 nanotubes, providing high surface area, fast diffusion path for ions and long-term cycle stability. Such a nanocomposite electrode is attractive for supercapacitor applications.

  1. Bone-like apatite growth on controllable macroporous titanium scaffolds coated with microporous titania.

    PubMed

    Rao, Xi; Li, Jing; Feng, Xue; Chu, Chenglin

    2018-01-01

    In this study, a simple, cost-effective approach of polymeric foam replication was used to produce three-dimensionally macroporous titanium scaffolds with controllable porosities and mechanical properties. Two kinds of porous titanium scaffolds with different porosities (74.7% and 87.6%) and pore sizes (360µm and 750µm) were fabricated. Both of the scaffolds exhibit good compressive strength (24.5MPa and 13.5MPa) with a low elastic modulus (0.23GPa and 0.11GPa), approximating the mechanical properties of nature human cancellous bone (E = 10-50MPa, σ = 0.01-3.0GPa). Thereafter, the scaffolds were surface modified using plasma electrolyte oxidation (PEO) process to gain a bioactive porous titania ceramic coating. The SBF immersion test indicates PEO treated scaffolds show excellent bioactivity as the apatite rapidly nucleates and grows on the scaffold surface during 3-28 days. The results suggest that the highly porous titanium scaffolds with titania bioactive coatings are promising in cancellous bone replacement. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Critical aspects in the production of periodically ordered mesoporous titania thin films.

    PubMed

    Soler-Illia, Galo J A A; Angelomé, Paula C; Fuertes, M Cecilia; Grosso, David; Boissiere, Cedric

    2012-04-21

    Periodically ordered mesoporous titania thin films (MTTF) present a high surface area, controlled porosity in the 2-20 nm pore diameter range and an amorphous or crystalline inorganic framework. These materials are nowadays routinely prepared by combining soft chemistry and supramolecular templating. Photocatalytic transparent coatings and titania-based solar cells are the immediate promising applications. However, a wealth of new prospective uses have emerged on the horizon, such as advanced catalysts, perm-selective membranes, optical materials based on plasmonics and photonics, metamaterials, biomaterials or new magnetic nanocomposites. Current and novel applications rely on the ultimate control of the materials features such as pore size and geometry, surface functionality and wall structure. Even if a certain control of these characteristics has been provided by the methods reported so far, the needs for the next generation of MTTF require a deeper insight in the physical and chemical processes taking place in their preparation and processing. This article presents a critical discussion of these aspects. This discussion is essential to evolve from know-how to sound knowledge, aiming at a rational materials design of these fascinating systems.

  3. Pore orientation effects on the kinetics of mesostructure loss in surfactant templated titania thin films

    DOE PAGES

    Das, Saikat; Nagpure, Suraj; Garlapalli, Ravinder K.; ...

    2016-12-17

    The mesostructure loss kinetics are measured as a function of the orientation of micelles in 2D hexagonal close packed (HCP) columnar mesostructured titania thin films using in situ grazing incidence small angle x-ray scattering (GISAXS). Complementary supporting information is provided by ex situ scanning electron microscopy. Pluronic surfactant P123 acts as the template to synthesize HCP structured titania thin films. When the glass substrates are modified with crosslinked P123, the micelles of the HCP mesophase align orthogonal to the films, whereas a mix of parallel and orthogonal alignment is found on unmodified glass. The rate of mesostructure loss of orthogonallymore » oriented (o-HCP) thin films (~60 nm thickness) prepared on modified substrate is consistently found to be less by a factor of 2.5 ± 0.35 than that measured for mixed orientation HCP films on unmodified substrates. The activation energy for mesostructure loss is only slightly greater for films on modified glass (155 ± 25 kJ/mol -1) than on unmodified (128 kJ/mol -1), which implies that the rate difference stems a greater activation entropy for mesostructure loss in o-HCP titania films. Nearly perfect orthogonal orientation of micelles on modified surfaces contributes to the lower rate of mesostructure loss by supporting the anisotropic stresses that develop within the films during annealing due to continuous curing, sintering and crystallization into the anatase phase during high temperature calcination (>450 °C). Because the film thickness dictates the propagation of orientation throughout the films and the degree of confinement, thicker (~250 nm) films cast onto P123-modified substrates have a much lower activation energy for mesostructure loss (89 ± 27 kJ/mol -1) due to the mix of orientations found in the films. Thus, in conclusion, this kinetic study shows that thin P123- templated o-HCP titania films are not only better able to achieve good orthogonal alignment of 3 the mesophase

  4. Pore orientation effects on the kinetics of mesostructure loss in surfactant templated titania thin films

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Das, Saikat; Nagpure, Suraj; Garlapalli, Ravinder K.

    The mesostructure loss kinetics are measured as a function of the orientation of micelles in 2D hexagonal close packed (HCP) columnar mesostructured titania thin films using in situ grazing incidence small angle x-ray scattering (GISAXS). Complementary supporting information is provided by ex situ scanning electron microscopy. Pluronic surfactant P123 acts as the template to synthesize HCP structured titania thin films. When the glass substrates are modified with crosslinked P123, the micelles of the HCP mesophase align orthogonal to the films, whereas a mix of parallel and orthogonal alignment is found on unmodified glass. The rate of mesostructure loss of orthogonallymore » oriented (o-HCP) thin films (~60 nm thickness) prepared on modified substrate is consistently found to be less by a factor of 2.5 ± 0.35 than that measured for mixed orientation HCP films on unmodified substrates. The activation energy for mesostructure loss is only slightly greater for films on modified glass (155 ± 25 kJ/mol -1) than on unmodified (128 kJ/mol -1), which implies that the rate difference stems a greater activation entropy for mesostructure loss in o-HCP titania films. Nearly perfect orthogonal orientation of micelles on modified surfaces contributes to the lower rate of mesostructure loss by supporting the anisotropic stresses that develop within the films during annealing due to continuous curing, sintering and crystallization into the anatase phase during high temperature calcination (>450 °C). Because the film thickness dictates the propagation of orientation throughout the films and the degree of confinement, thicker (~250 nm) films cast onto P123-modified substrates have a much lower activation energy for mesostructure loss (89 ± 27 kJ/mol -1) due to the mix of orientations found in the films. Thus, in conclusion, this kinetic study shows that thin P123- templated o-HCP titania films are not only better able to achieve good orthogonal alignment of 3 the mesophase

  5. High surface area neodymium phosphate nano particles by modified aqueous sol-gel method

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sankar, Sasidharan; Warrier, Krishna Gopakumar, E-mail: wwarrierkgk@yahoo.co.in; Komban, Rajesh

    2011-12-15

    Graphical abstract: Synthesis of nano rod shaped neodymium phosphate particles with specific surface area as high as 107 m{sup 2} g{sup -1} and particles could be compacted and sintered at as low as 1300 Degree-Sign C to a density of 98.5% (theoretical) with an average grain size of {approx}1 {mu}m. Highlights: Black-Right-Pointing-Pointer Nano size neodymium phosphate is synthesized and characterized using a novel modified aqueous sol gel process. Black-Right-Pointing-Pointer Specific surface area above 100 m{sup 2} g{sup -1} achieved without the addition of any complexing agents. Black-Right-Pointing-Pointer High sintered density reported than the density obtained for powder synthesized through conventionalmore » solid state reaction. Black-Right-Pointing-Pointer The particles are nano sized and have rod shape morphology and are retained at higher temperatures. Black-Right-Pointing-Pointer An average grain size of {approx}1 {mu}m obtained for sintered NdPO{sub 4} after thermal etching at 1400 Degree-Sign C. -- Abstract: Synthesis of nano rod shaped neodymium phosphate (NdPO{sub 4}) particles with specific surface area as high as 107 m{sup 2}g{sup -1} and an average length of 50 nm with aspect ratio 5 was achieved using modified sol gel method. Crystallite size calculated from the X-ray diffraction data by applying Scherer equation was 5 nm for the precursor gel after calcination at 400 Degree-Sign C. NdPO{sub 4} was first precipitated from neodymium nitrate solution using phosphoric acid followed by peptization using dilute nitric acid and further gelation in ammonia atmosphere. The calcined gel powders were further characterized by surface area (Brunauer-Emmet-Teller nitrogen adsorption analysis), Transmission electron microscopy, scanning electron microscopy, UV-vis and FT-IR analysis. Transmission electron microscopy confirms the formation of rod like morphology from the sol, gel and the calcined particles in nano size range. These particles could be

  6. Novel secondary assembled micro/nano porous spheres ZnCo2O4 with superior electrochemical performances as lithium ion anode material.

    PubMed

    Liu, Haowen; Hu, Qihong

    2018-08-10

    In this work, novel secondary assembled micro/nano porous spheres ZnCo 2 O 4 were firstly prepared by combining the hydrothermal method with post-synthesis calcinations. The structure and morphology of the obtained powder were characterized by x-ray powder diffraction and field emission-scanning electron microscopy. As the anode material of lithium-ion half-cells, the as-prepared ZnCo 2 O 4 delivered a very high capacity, extra cycling stability and excellent rate capability. A discharge capacity of 950 mAh g -1 with up to 99.7% retention corresponding to the second cycle at 0.1 C was achieved after 90 cycles, which was an improved cyclability over previous reports. The higher current charge-discharge and electrochemical impedance spectroscopy data indicate that the material's integrity was maintained. Therefore constructing the secondary assembled 3D micro/nano structure is an effective strategy to obtain the superior electrochemical performances.

  7. CAPTURE OF MERCURY IN COMBUSTION SYSTEMS BY IN SITU-GENERATED TITANIA PARTICLES WITH UV IRRADIATION

    EPA Science Inventory

    In-situ-generated sorbent titania particles with ultraviolet (UV) irradiation have been shown to be effective in capture of mercury in combustor exhausts. Results of experiments conducted with the (1) sorbent precursor only, (2) mercury only, (3) mercury and UV irradiation, and (...

  8. Synthesis and mechanical/magnetic properties of nano-grained iron-oxides prepared with an inert gas condensation and pulse electric current sintering process

    NASA Astrophysics Data System (ADS)

    Choa, Yong-Ho; Nakayama, Tatachika; Sekino, Tohru; Niihara, Koichi

    1999-04-01

    Nanocrystalline iron-oxide powder was fabricated with an inert gas condensation (IGC) method combined with evaporation, and in-situ oxidation techniques. The particle size of iron-oxide powder was controlled by varying the helium gas pressure between 0.1 and 10 Torr, with the smallest one =10 nm at 0.1 Torr. The nanostructure was characterized by TEM. Nanocrystalline iron-oxide powder was sintered with the pulse electric current sintering (PECS) method to obtain densified γ-Fe2O3 materials, and suitably densified nano-grained γ-Fe2O3 materials (≈ 40 nm) of great hardness were obtained. The correlation between the nanostructure and magnetic properties of nanocrystalline powder and densified γ-Fe2O3 materials was also investigated.

  9. Nano-Sized Natural Colorants from Rocks and Soils

    NASA Astrophysics Data System (ADS)

    Ahmad, W. Y. W.; Ruznan, W. S.; Hamid, H. A.; Kadir, M. I. A.; Yusoh, M. K. M.; Ahmad, M. R.

    2010-03-01

    Colored rocks (lateritic) and soils (shales) are available in abundant all around Malaysia and they are from natural sources. The colorants will be useful if they can be transferred to substrates using dyeing, printing or brushing with acceptable fastness. First of all the rocks need to be crushed into powder form before coloration can take place. The sizes of the colorants particles obtained with coffee grinder were of 7-8 microns. They can be reduced to 3-5 micron using fluidized bed jetmill and to nano sizes with the help of planetary mono mill grinders. The experiment was conducted in both dyeing and printing of textiles using all three sizes (7-8 microns, 3-5 microns and nano sizes) of colorants on silk fabric. The colorants were applied on silk fabrics by dyeing and tie and dye techniques. In addition, the colorants can also be applied by brushing technique as in batik canting or batik block as well as silk screen printing. The evaluations of colored materials were based on the levelness of dyeing, fastness properties (washing, light and rubbing fastness) and color strength. The wash fastness testing shows that all colorants sizes have more or less the same fastness to washing but nano sized colorants produced better uniform dyes distribution (levelness of dyeing) and higher color strength.

  10. Dispersion of nano-silicon carbide (SiC) powder in aqueous suspensions

    NASA Astrophysics Data System (ADS)

    Singh, Bimal P.; Jena, Jayadev; Besra, Laxmidhar; Bhattacharjee, Sarama

    2007-10-01

    The dispersion characteristics of nanosize silicon carbide (SiC) suspension were investigated in terms of surface charge, particle size, rheological measurement and adsorption study. Ammonium polycarboxylate has been used as dispersant to stabilize the suspension. It was found that the isoelectric point (iep) of SiC powder was pHiep (4.9). The surface charge of powder changed significantly in presence of the ammonium polycarboxylate dispersant and iep shifted significantly towards lower acidic pH (3.6). The shift in iep has been quantified in terms of Δ G 0 SP, the specific free energy of adsorption between the surface sites and the adsorbing polyelectrolyte (APC). The values of Δ G 0 SP (-10.85 RT unit) estimated by the electro kinetic data compare well with those obtained from adsorption isotherms (-9.521 RT unit). The experimentally determined optimum concentration of dispersant required for maximizing the dispersion was found to be 2.4 mg/g of SiC (corresponding to an adsorbed amount of 1.10 mg/g), at pH 7.5. This is much below the full monolayer coverage (corresponding to adsorbed amount of 1.75 mg/g) of the particles surface by the dispersant. The surface charge quantity, rheological, pH, electro kinetic and adsorption isotherm results were used to explain and correlate the stability of the nanosize silicon carbide in aqueous media. At pH 7.5, where both SiC surface and APC are negatively charged, the adsorption of APC was low because of limited availability of favourable adsorption sites. In addition, the brush-like configuration of the adsorbed polymer prevented close approach of any additional dispersant; hence stabilization of the slurry happens at a comparatively lower concentration than the monolayer coverage.

  11. Effect of freeze-dried leek powder (FDLP) and nitrite level on processing and quality characteristics of fermented sausages.

    PubMed

    Tsoukalas, D S; Katsanidis, E; Marantidou, S; Bloukas, J G

    2011-02-01

    Fermented sausages were produced with 0.84% and 1.68% freeze-dried leek powder (FDLP), providing 75 and 150 mg/kg NaNO(3), respectively, and three levels of added nitrite (0, 75, and 150 mg/kg NaNO(2). A control treatment was also produced with 150 mg/kg NaNO(2). Sausages with FDLP were darker and yellower (p<0.05) than the control. Higher FDLP levels produced less red, yellower and darker sausages (p<0.05). Lower FDLP levels resulted in higher (p<0.05) sensory scores for external appearance, flavour and overall acceptability. No differences were found among the treatments with FDLP plus 75 or 150 ppm NaNO(2) in TBA value, lightness, redness (cross section), redness stability, yellowness, texture parameters and sensory firmness, flavour and overall acceptability. The use of 0.84% FDLP and 75 ppm NaNO₂ is considered more appropriate for the production of fermented sausages, as it results in a 50% reduction in added nitrite. Copyright © 2010 Elsevier Ltd. All rights reserved.

  12. Controlling drug delivery kinetics from mesoporous titania thin films by pore size and surface energy.

    PubMed

    Karlsson, Johan; Atefyekta, Saba; Andersson, Martin

    2015-01-01

    The osseointegration capacity of bone-anchoring implants can be improved by the use of drugs that are administrated by an inbuilt drug delivery system. However, to attain superior control of drug delivery and to have the ability to administer drugs of varying size, including proteins, further material development of drug carriers is needed. Mesoporous materials have shown great potential in drug delivery applications to provide and maintain a drug concentration within the therapeutic window for the desired period of time. Moreover, drug delivery from coatings consisting of mesoporous titania has shown to be promising to improve healing of bone-anchoring implants. Here we report on how the delivery of an osteoporosis drug, alendronate, can be controlled by altering pore size and surface energy of mesoporous titania thin films. The pore size was varied from 3.4 nm to 7.2 nm by the use of different structure-directing templates and addition of a swelling agent. The surface energy was also altered by grafting dimethylsilane to the pore walls. The drug uptake and release profiles were monitored in situ using quartz crystal microbalance with dissipation (QCM-D) and it was shown that both pore size and surface energy had a profound effect on both the adsorption and release kinetics of alendronate. The QCM-D data provided evidence that the drug delivery from mesoporous titania films is controlled by a binding-diffusion mechanism. The yielded knowledge of release kinetics is crucial in order to improve the in vivo tissue response associated to therapeutic treatments.

  13. Effect of Nano-SiO2 on the Hydration and Microstructure of Portland Cement

    PubMed Central

    Wang, Liguo; Zheng, Dapeng; Zhang, Shupeng; Cui, Hongzhi; Li, Dongxu

    2016-01-01

    This paper systematically studied the modification of cement-based materials by nano-SiO2 particles with an average diameter of about 20 nm. In order to obtain the effect of nano-SiO2 particles on the mechanical properties, hydration, and pore structure of cement-based materials, adding 1%, 3%, and 5% content of nano-SiO2 in cement paste, respectively. The results showed that the reaction of nano-SiO2 particles with Ca(OH)2 (crystal powder) started within 1 h, and formed C–S–H gel. The reaction speed was faster after aging for three days. The mechanical properties of cement-based materials were improved with the addition of 3% nano-SiO2, and the early strength enhancement of test pieces was obvious. Three-day compressive strength increased 33.2%, and 28-day compressive strength increased 18.5%. The exothermic peak of hydration heat of cement increased significantly after the addition of nano-SiO2. Appearance time of the exothermic peak was advanced and the total heat release increased. Thermogravimetric-differential scanning calorimetry (TG-DSC) analysis showed that nano-SiO2 promoted the formation of C–S–H gel. The results of mercury intrusion porosimetry (MIP) showed that the total porosity of cement paste with 3% nano-SiO2 was reduced by 5.51% and 5.4% at three days and 28 days, respectively, compared with the pure cement paste. At the same time, the pore structure of cement paste was optimized, and much-detrimental pores and detrimental pores decreased, while less harmful pores and innocuous pores increased. PMID:28335369

  14. Effect of milling time on microstructure and properties of Nano-titanium polymer by high-energy ball milling

    NASA Astrophysics Data System (ADS)

    Wang, Bo; Wei, Shicheng; Wang, Yujiang; Liang, Yi; Guo, Lei; Xue, Junfeng; Pan, Fusheng; Tang, Aitao; Chen, Xianhua; Xu, Binshi

    2018-03-01

    Nano-titanium (Nano-Ti) was prepared by high-energy ball milling from pure Ti power and grinding agents (Epoxy resin) at room temperature. The effect of milling time on structure and properties of Nano-Ti polymer were investigated systematically. The results show that high-energy ball milling is an effective way to produce Nano-Ti polymer. The dispersion stability and compatibility between Ti power and grinding agents are improved by prolonging the milling time at a certain degree, that is to say, the optimization milling time is 240 min. The particle size of Ti powder and the diffraction peaks intensity of Ti decrease obviously as the milling time increases due to the compression stress, shear friction and other mechanical forces are formed during ball milling. FT-IR result displays that the wavenumber of all the bands move to lower wavenumber after ball milling, and the epoxy ring is open. The system internal energy rises owing to the broken epoxy group and much more Nano-Ti is formed to promote the grafting reaction between Nano-Ti and epoxy resin. The results from TEM and XPS also prove that. And the grafting ration is maximum as the milling time is 240 min, the mass loss ratio is 17.53%.

  15. Heterogeneous Decomposition of Volatile Organic Compounds by Visible-Light Activated N, C, S-Embedded Titania.

    PubMed

    Chun, Ho-Hwan; Jo, Wan-Kuen

    2016-05-01

    In this study, a N-, C-, and S-doped titania (NCS-TiO2) composite was prepared by combining the titanium precursor with a single dopant source, and the photocatalytic activity of this system for the decomposition of volatile organic compounds (VOCs) at indoor-concentration levels, under exposure to visible light, was examined. The NCS-TiO2 composite and the pure TiO2 photocatalyst, used as a reference, were characterized via X-ray diffraction, scanning electron microscopy, ultraviolet-visible diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The average efficiencies of benzene, toluene, ethyl benzene, and o-xylene decomposition using NCS-TiO2 for were 70, 87, -100, and -100%, respectively, whereas the values obtained using the pure TiO2 powder were -0, 18, 49, and 51%, respectively. These results suggested that, for the photocatalytic decomposition of toxic VOCs under visible-light exposure conditions, NCS-TiO2 was superior to the reference photocatalyst. The decomposition efficiencies of the target VOCs were inversely related to the initial concentration and relative humidity as well as to the air-flow rate. The decomposition efficiencies of the target chemicals achieved with a conventional lamp/NCS-TiO2 system were higher than those achieved with a light emitting diode/NCS-TiO2 system. Overall, NCS-TiO2 can be used for the efficient decomposition of VOCs under visible-light exposure, if the operational conditions are optimized.

  16. TiO2 -enriched polymeric powder coatings support human mesenchymal cell spreading and osteogenic differentiation.

    PubMed

    Mozumder, Mohammad Sayem; Zhu, Jesse; Perinpanayagam, Hiran

    2011-06-01

    Novel polymeric powder coatings (PPC) were prepared by ultrafine powder coating technology and shown to support human mesenchymal cell attachment and growth. PPC surfaces enriched with nano-TiO(2) (nTiO(2)) showed enhanced cellular responses, and were compared to commercially pure titanium (cpTi). After cell attachment and growth, osteogenic differentiation and bone matrix formation ensures osseointegration for implantable biomaterials. Therefore, the objective of this study was to determine if mesenchymal cells grown on PPC could undergo osteogenic differentiation by inducing Runx2 and bone matrix proteins, and then initiate mineralization. Atomic force microscopy revealed intricate three-dimensional micro-topographies, and the measures of nano-roughness and porosity were similar for all PPC surfaces. Scanning electron microscopy showed that the cells attached and spread out over all of the surfaces. After 1 week in osteogenic media, RT-PCR analysis showed the induction of Runx2, the up-regulation of type I collagen, and the initial detection of alkaline phosphatase and bone sialoprotein. After 4 weeks, Alizarin Red staining showed mineral deposition. However, cell spreading and osteogenic differentiation were significantly (P < 0.05) higher on the cpTi controls than on the PPC surfaces. Furthermore, spreading and differentiation were consistently higher on the titanium-enriched PPC-2, -3 and -4 than on the titanium-free PPC-1. Therefore, despite the presence of complex micro-topographies and nano-features, titanium-enrichment enhanced the cellular response, and pure titanium still provided the best substrate. These findings confirm the cytocompatibility of these novel polymeric coatings and suggest that titanium-enrichment and nTiO(2) additives may enhance their performance.

  17. Nano-coating of beta-galactosidase onto the surface of lactose by using an ultrasound-assisted technique.

    PubMed

    Genina, Natalja; Räikkönen, Heikki; Heinämäki, Jyrki; Veski, Peep; Yliruusi, Jouko

    2010-06-01

    We nano-coated powdered lactose particles with the enzyme beta-galactosidase using an ultrasound-assisted technique. Atomization of the enzyme solution did not change its activity. The amount of surface-attached beta-galactosidase was measured through its enzymatic reaction product D-galactose using a standardized method. A near-linear increase was obtained in the thickness of the enzyme coat as the treatment proceeded. Interestingly, lactose, which is a substrate for beta-galactosidase, did not undergo enzymatic degradation during processing and remained unchanged for at least 1 month. Stability of protein-coated lactose was due to the absence of water within the powder, as it was dry after the treatment procedure. In conclusion, we were able to attach the polypeptide to the core particles and determine precisely the coating efficiency of the surface-treated powder using a simple approach.

  18. Powder treatment process

    DOEpatents

    Weyand, J.D.

    1988-02-09

    Disclosed are: (1) a process comprising spray drying a powder-containing slurry, the slurry containing a powder constituent susceptible of oxidizing under the temperature conditions of the spray drying, while reducing the tendency for oxidation of the constituent by including as a liquid constituent of the slurry an organic liquid; (2) a process comprising spray drying a powder-containing slurry, the powder having been pretreated to reduce content of a powder constituent susceptible of oxidizing under the temperature conditions of the spray drying, the pretreating comprising heating the powder to react the constituent; and (3) a process comprising reacting ceramic powder, grinding the reacted powder, slurrying the ground powder, spray drying the slurried powder, and blending the dried powder with metal powder. 2 figs.

  19. Powder treatment process

    DOEpatents

    Weyand, John D.

    1988-01-01

    (1) A process comprising spray drying a powder-containing slurry, the slurry containing a powder constituent susceptible of oxidizing under the temperature conditions of the spray drying, while reducing the tendency for oxidation of the constituent by including as a liquid constituent of the slurry an organic liquid; (2) a process comprising spray drying a powder-containing slurry, the powder having been pretreated to reduce content of a powder constituent susceptible of oxidizing under the temperature conditions of the spray drying, the pretreating comprising heating the powder to react the constituent; and (3) a process comprising reacting ceramic powder, grinding the reacted powder, slurrying the ground powder, spray drying the slurried powder, and blending the dried powder with metal powder.

  20. Dielectric Measurements on Sol-Gel Derived Titania Films

    NASA Astrophysics Data System (ADS)

    Capan, Rifat; Ray, Asim K.

    2017-11-01

    Alternating current (AC) impedance measurements were performed on 37 nm thick nanostructured sol-gel derived anatase titania films on ultrasonically cleaned (100) p-silicon substrates at temperatures T ranging from 100 K to 300 K over a frequency range between 20 Hz and 1 MHz. The frequency-dependent behavior of the AC conductivity σ ac( f, T) obeys the universal power law, and the values of the effective hopping barrier and hopping distance were found to be 0.79 eV and 6.7 × 10-11 m from an analysis due to the correlated barrier-hopping model. The dielectric relaxation was identified as a thermally activated non-Debye process involving an activation energy of 41.5 meV.

  1. Titania inverse opals for infrared optical applications

    NASA Astrophysics Data System (ADS)

    Lanata, M.; Cherchi, M.; Zappettini, A.; Pietralunga, S. M.; Martinelli, M.

    2001-06-01

    Photonic crystals have gathered great importance in recent years. In particular macroporous materials (inverse opals) show interesting properties as photonic crystals. Ordered macroporous titanium dioxide (TiO 2) is made using polystyrene spheres as a template. Titania is chosen for its high refractive index (>2.5). Following an already known technique [E.G. Judith, J. Wijnhoven, W.L. Vos, Science 281 (1998) 802; B.T. Holland, C.F. Blanford, A. Stein, Science 281 (1998) 538; B.T. Holland, C.F. Blanford, T. Do, A. Stein, Chem. Mater. 11 (1999) 795] large-scale order in macroporous TiO 2 is obtained both using the 778 and the 3190 nm beads as documented by optical microscope and SEM images. These structures would lead to applications in the mid-infrared range.

  2. Attenuated total reflection fourier transform infrared spectroscopy towards disclosing mechanism of bacterial adhesion on thermally stabilized titanium nano-interfaces.

    PubMed

    Gopal, Judy; Chun, Sechul; Doble, Mukesh

    2016-08-01

    Titanium is widely used as medical implant material and as condenser material in the nuclear industry where its integrity is questioned due to its susceptibility to bacterial adhesion. A systematic investigation on the influence of thermally (50-800 °C) stabilized titanium (TS-Ti) nano oxide towards bacterial adhesion was carried out. The results showed that below 350 °C significant bacterio-phobicity was observed, while above 500 °C significant affinity towards bacterial cells was recorded. Conventional characterization tools such as HR-TEM and XRD did not provide much insight on the changes occurring on the oxide film with heat treatment, however, attenuated total reflection fourier transform infrared spectroscopy (ATR-FTIR) of the surface showed significant changes in the spectral pattern as a function of increasing heat treatment. It was observed that elevated OH, N-H and C=O groups and rutile titania on the TS-Ti oxide films led to higher affinity for bacterial adhesion. On the other hand low temperature TS-Ti nanooxide films (<350 °C) showed high C-H groups and decreased OH groups on their surface, which possibly contributed towards their bacterio-phobicity. The TS-Ti nanooxide film grown at 50 °C was observed to be the most efficient anti-bacterial adhesion interface, while the 800 °C interface was the one showing highest affinity towards bacterial adhesion. This study confirms the successful application of ATR-FTIR technique for nano-oxide film characterization and towards understanding the variations in bacterial interaction of such nano interfaces.

  3. Effect of Embedding Cu-Graphene Hybrid Powder into 2-Phase In-Cu Solders on Its Suitability as Metallic Thermal Interface Material

    NASA Astrophysics Data System (ADS)

    Sharma, Deepak; Jain, Aman; Somaiah, Nalla; Narayanan, P. Ramesh; Kumar, Praveen

    2018-05-01

    The effect of embedding Cu-graphene hybrid powder, namely "graphene nano-sheet Cu" (GNS-Cu) powder, into In-40 vol.% Cu solder alloy on the electrical and mechanical properties of In-Cu solder is investigated. GNS-Cu hybrid powders were prepared by mixing reduced graphene oxide powders and CuSO4·5H2O, followed by reduction of the mixture with hydrazine. Subsequently, In-Cu solders with GNS-Cu powders were prepared using a 2-step process, comprising liquid phase sintering (LPS) of In and Cu powders followed by accumulative roll bonding (ARB). During ARB, the GNS-Cu powders were embedded as distinct layers into In-Cu composite solders. Electrical conductivity of the GNS-Cu embedded solders increased by > 20% as compared to pure In-Cu solders processed through the same combination of LPS-ARB steps. The yield strength of In-Cu solder increased by only 10% with the addition of GNS-Cu powders and thus retained the moderate strength often associated with pure In-Cu composite solders. Moreover, the thermal conductivity of GNS-Cu-embedded solders was estimated theoretically to increase by > 60%. These promising findings suggest that GNS-Cu-embedded In-Cu solders can be suitable for next-generation metallic thermal interface material and package-level interconnect applications.

  4. Disintegration of nano-embedded microparticles after deposition on mucus: A mechanistic study.

    PubMed

    Ruge, Christian A; Bohr, Adam; Beck-Broichsitter, Moritz; Nicolas, Valérie; Tsapis, Nicolas; Fattal, Elias

    2016-03-01

    The conversion of colloidal drug carriers/polymeric nanoparticles into dry microparticulate powders (e.g., by spray-drying) is a prominent approach to overcome the aerodynamic limitations of these formulations for delivery via inhalation. However, to what extent such nano-embedded microparticles disintegrate into individual/intact nanoparticles after contacting relevant physiological media has so far not been addressed. Polymeric nanoparticles were spray-dried into nano-embedded microparticles (NEMs) using different amounts of trehalose as embedding matrix excipient. Formulations were characterized and then evaluated for their disintegration behavior after aerosolization onto model mucus. Although a rapid and complete aqueous redispersion was observed for specific excipient/nanoparticle weight ratios (i.e., greater than 1/1), the same formulations revealed no disintegration after deposition onto a static mucus layer. Double-labeled NEMs powders (i.e., dual color staining of polymeric nanoparticles and trehalose) demonstrated rapid matrix dissolution, while the nanoparticle aggregates persisted. When deposited onto agitated mucus, however, sufficient disintegration of NEMs into individual polymeric nanoparticles was observed. These findings indicate that mechanical forces are necessary to overcome the attraction between individual nanoparticles found within the NEMs. Thus, it remains questionable whether the lung mechanics (e.g., breathing, mucociliary clearance) acting on these formulations will contribute to the overall disintegration process. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Synthesis and Characterization of Cholesterol Nano Particles by Using w/o Microemulsion Technique

    NASA Astrophysics Data System (ADS)

    Vyas, Poorvesh M.; Vasant, Sonal R.; Hajiyani, Rakesh R.; Joshi, Mihir J.

    2010-10-01

    Cholesterol is one of the most abundant and well known steroids in the animal kingdom. Cholesterol rich micro-emulsions and nano-emulsions are useful for the treatment of breast cancer and gynecologic cancers. The nano particles of cholesterol and other pharmaceutically important materials have been reported. In the present investigation, the nano particles of cholesterol were synthesized by direct precipitation technique using triton X-100/water/n-butanol micro-emulsion. The average particle size of cholesterol nano particles was estimated by applying Scherrer's formula to the powder X-ray diffraction pattern, which was found to be 22 nm. The nanoparticles of cholesterol were observed by using TEM and the particle size was found within the range from 15 nm-31 nm. The distribution of particle size was studied through DLS. The nanoparticles of cholesterol were characterized by using FT-IR spectroscopy and the force constant was also calculated for O-H, C-H and C-O bonds. The thermal response of nanoparticles of cholesterol was studied by TGA, which showed that the nanoparticles were stable up to 200 °C and then decomposed. Kinetic and thermodynamic parameters of decomposition process were also calculated by applying Coats and Redfern formula to thermo-gram.

  6. Study of linear optical parameters of sodium sulphide nano-particles added ADP crystals

    NASA Astrophysics Data System (ADS)

    Kochuparampil, A. P.; Joshi, J. H.; Dixit, K. P.; Jethva, H. O.; Joshi, M. J.

    2017-05-01

    Ammonium Dihydrogen Phosphate (ADP) is one of the nonlinear optical crystals. It is having various applications like optical mixing, electro-optical modulator, harmonic generators, etc. Chalcogenide compounds are poorly soluble in water and difficult to add in the water soluble ADP crystals. The solubility of Chalcogenide compounds can be increased by synthesizing the nano-structured samples with suitable capping agent. In the present study sodium sulphide was added in to ADP to modify its linear optical parameters. Sodium sulphide nano particles were synthesized by co-precipitation technique using Ethylene diamine as capping agent followed by microwave irradiation. The powder XRD confirmed the nano-structured nature of sodium sulphide nano particles. The solubility of nanoparticles of sodium sulphide increased significantly in water compared to the bulk. Pure and Na2S added ADP crystals were grown by slow solvent evaporation method at room temperature. The presence of sodium in ADP was confirmed by AAS. The UV-Vis spectra were recorded for all crystals. Various optical parameters like, transmittance, energy band gap, extinction coefficient, refractive index, optical conductivity, etc. were evaluated. The electronic polarizibility of pure and doped crystals calculated from energy band gap. The effect of doping concentration was found on various parameters.

  7. Optimizing Cr(VI) and Tc(VII) remediation through nano-scale biomineral engineering

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cutting, R. S.; Coker, V. S.; Telling, N. D.

    2009-09-09

    To optimize the production of biomagnetite for the bioremediation of metal oxyanion contaminated waters, the reduction of aqueous Cr(VI) to Cr(III) by two biogenic magnetites and a synthetic magnetite was evaluated under batch and continuous flow conditions. Results indicate that nano-scale biogenic magnetite produced by incubating synthetic schwertmannite powder in cell suspensions of Geobacter sulfurreducens is more efficient at reducing Cr(VI) than either biogenic nano-magnetite produced from a suspension of ferrihydrite 'gel' or synthetic nano-scale Fe{sub 3}O{sub 4} powder. Although X-ray Photoelectron Spectroscopy (XPS) measurements obtained from post-exposure magnetite samples reveal that both Cr(III) and Cr(VI) are associated with nanoparticlemore » surfaces, X-ray Magnetic Circular Dichroism (XMCD) studies indicate that some Cr(III) has replaced octahedrally coordinated Fe in the lattice of the magnetite. Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) measurements of total aqueous Cr in the associated solution phase indicated that, although the majority of Cr(III) was incorporated within or adsorbed to the magnetite samples, a proportion ({approx}10-15 %) was released back into solution. Studies of Tc(VII) uptake by magnetites produced via the different synthesis routes also revealed significant differences between them as regards effectiveness for remediation. In addition, column studies using a {gamma}-camera to obtain real time images of a {sup 99m}Tc(VII) radiotracer were performed to visualize directly the relative performances of the magnetite sorbents against ultra-trace concentrations of metal oxyanion contaminants. Again, the magnetite produced from schwertmannite proved capable of retaining more ({approx}20%) {sup 99m}Tc(VII) than the magnetite produced from ferrihydrite, confirming that biomagnetite production for efficient environmental remediation can be fine-tuned through careful selection of the initial Fe(III) mineral

  8. Preparation of bioactive titania films on titanium metal via anodic oxidation.

    PubMed

    Cui, X; Kim, H-M; Kawashita, M; Wang, L; Xiong, T; Kokubo, T; Nakamura, T

    2009-01-01

    To research the crystal structure and surface morphology of anodic films on titanium metal in different electrolytes under various electrochemical conditions and investigate the effect of the crystal structure of the oxide films on apatite-forming ability in simulated body fluid (SBF). Titanium oxide films were prepared using an anodic oxidation method on the surface of titanium metal in four different electrolytes: sulfuric acid, acetic acid, phosphoric acid and sodium sulfate solutions with different voltages for 1 min at room temperature. Anodic films that consisted of rutile and/or anatase phases with porous structures were formed on titanium metal after anodizing in H(2)SO(4) and Na(2)SO(4) electrolytes, while amorphous titania films were produced after anodizing in CH(3)COOH and H(3)PO(4) electrolytes. Titanium metal with the anatase and/or rutile crystal structure films showed excellent apatite-forming ability and produced a compact apatite layer covering all the surface of titanium after soaking in SBF for 7d, but titanium metal with amorphous titania layers was not able to induce apatite formation. The resultant apatite layer formed on titanium metal in SBF could enhance the bonding strength between living tissue and the implant. Anodic oxidation is believed to be an effective method for preparing bioactive titanium metal as an artificial bone substitute even under load-bearing conditions.

  9. Solid-phase extraction-fluorimetric high performance liquid chromatographic determination of domoic acid in natural seawater mediated by an amorphous titania sorbent.

    PubMed

    Chan, Ivy O M; Tsang, Vic W H; Chu, K K; Leung, S K; Lam, Michael H W; Lau, T C; Lam, Paul K S; Wu, Rudolf S S

    2007-01-30

    The feasibility of using sol-gel amorphous titania (TiO2) as a solid-phase sorbent for the pre-concentration of domoic acid (DA), a potent amnesic shellfish poisoning (ASP) toxin, directly from seawater was explored. The sol-gel titania material is able to adsorb DA from seawater, via the formation of ester-linkage between the carboxylic moieties of DA and the Ti-OH groups on the sorbent surface, at low pH and desorb it at high pH. The chemisorption process is not significantly interfered by the seawater matrix. The optimum pH values for the adsorption and desorption of DA were found to be pH 4 and 11, respectively. The optimal sorbent loading for the batch-type solid-phase extraction of DA was 0.67 mg-TiO2 ng-DA(-1) and adsorption equilibrium was achieved in 2 h at room temperature. The desorbed DA in 500 microL of 0.1 M alkaline borate buffer can be directly derviatized by 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) in aqueous media for fluorimetric HPLC quantification. Analyte recovery, repeatability and detection limit of this titania SPE-fluorimetric HPLC determination are 89%, 6.2% and 120 pg-DA mL(-1) (n=7, P<0.05), respectively, for a sample volume of 30 mL. This titania SPE technique should also be applicable to the pre-concentration of other polar carboxylate- and phosphonate-containing biomolecules and pharmaceuticals in complex and interfering environmental sample matrices.

  10. Efficacy of radiosensitizing doped titania nanoparticles under hypoxia and preparation of an embolic microparticle

    PubMed Central

    Morrison, Rachel A; Rybak-Smith, Malgorzata J; Thompson, James M; Thiebaut, Bénédicte; Hill, Mark A; Townley, Helen E

    2017-01-01

    The aim of this study was to develop a manufacturing protocol for large-scale production of doped titania radiosensitizing nanoparticles (NPs) to establish their activity under hypoxia and to produce a multimodal radiosensitizing embolic particle for cancer treatment. We have previously shown that radiosensitizing NPs can be synthesized from titania doped with rare earth elements, especially gadolinium. To translate this technology to the clinic, a crucial step is to find a suitable, scalable, high-throughput method. Herein, we have described the use of flame spray pyrolysis (FSP) to generate NPs from titanium and gadolinium precursors to produce titania NPs doped with 5 at% gadolinium. The NPs were fully characterized, and their capacity to act as radiosensitizers was confirmed by clonogenic assays. The integrity of the NPs in vitro was also ascertained due to the potentially adverse effects of free gadolinium in the body. The activity of the NPs was then studied under hypoxia since this is often a barrier to effective radiotherapy. In vitro radiosensitization experiments were performed with both the hypoxia mimetics deferoxamine and cobalt chloride and also under true hypoxia (oxygen concentration of 0.2%). It was shown that the radiosensitizing NPs were able to cause a significant increase in cell death even after irradiation under hypoxic conditions such as those found in tumors. Subsequently, the synthesized NPs were used to modify polystyrene embolization microparticles. The NPs were sintered to the surface of the microparticles by heating at 230°C for 15 minutes. This resulted in a good coverage of the surface and to generate embolization particles that were shown to be radiosensitizing. Such multimodal particles could therefore result in occlusion of the tumor blood vessels in conjunction with localized reactive oxygen species generation, even under hypoxic conditions such as those found in the center of tumors. PMID:28572729

  11. Efficacy of radiosensitizing doped titania nanoparticles under hypoxia and preparation of an embolic microparticle.

    PubMed

    Morrison, Rachel A; Rybak-Smith, Malgorzata J; Thompson, James M; Thiebaut, Bénédicte; Hill, Mark A; Townley, Helen E

    2017-01-01

    The aim of this study was to develop a manufacturing protocol for large-scale production of doped titania radiosensitizing nanoparticles (NPs) to establish their activity under hypoxia and to produce a multimodal radiosensitizing embolic particle for cancer treatment. We have previously shown that radiosensitizing NPs can be synthesized from titania doped with rare earth elements, especially gadolinium. To translate this technology to the clinic, a crucial step is to find a suitable, scalable, high-throughput method. Herein, we have described the use of flame spray pyrolysis (FSP) to generate NPs from titanium and gadolinium precursors to produce titania NPs doped with 5 at% gadolinium. The NPs were fully characterized, and their capacity to act as radiosensitizers was confirmed by clonogenic assays. The integrity of the NPs in vitro was also ascertained due to the potentially adverse effects of free gadolinium in the body. The activity of the NPs was then studied under hypoxia since this is often a barrier to effective radiotherapy. In vitro radiosensitization experiments were performed with both the hypoxia mimetics deferoxamine and cobalt chloride and also under true hypoxia (oxygen concentration of 0.2%). It was shown that the radiosensitizing NPs were able to cause a significant increase in cell death even after irradiation under hypoxic conditions such as those found in tumors. Subsequently, the synthesized NPs were used to modify polystyrene embolization microparticles. The NPs were sintered to the surface of the microparticles by heating at 230°C for 15 minutes. This resulted in a good coverage of the surface and to generate embolization particles that were shown to be radiosensitizing. Such multimodal particles could therefore result in occlusion of the tumor blood vessels in conjunction with localized reactive oxygen species generation, even under hypoxic conditions such as those found in the center of tumors.

  12. Molecular adsorption of hydrogen peroxide on N- and Fe-doped titania nanoclusters

    NASA Astrophysics Data System (ADS)

    Mohajeri, Afshan; Dashti, Nasimeh Lari

    2017-06-01

    Titanium dioxide (titania) nanoparticles have been extensively investigated for photocatalytic applications such as the decomposition and adsorption of pollutant and undesirable compound in air and waste water. In this context, the present article reports the molecular adsorption of hydrogen peroxide on the surface of doped titania clusters. Density functional theory calculations were performed to investigate the structures and electronic properties of two nanoscale (TiO2)n clusters (n = 5,6) modified by nitrogen and iron dopants. The relative stability of all possible N-doped and Fe-doped isomers has been compared with each other and with the parent cluster. It was found that the Fe-doped clusters are in general more stable than the N-doped counterparts. Moreover, after N/Fe doping an enhanced in the magnetization of the clusters is observed. In the second part, we have investigated different modes of H2O2 adsorption on the lowest-energy isomers of doped clusters. In almost all the cases, the adsorptions on the doped clusters are found to be less exothermic than on the corresponding undoped parent cluster. Our results highlight the essential role of charge transfer into the interaction between H2O2 and doped (TiO2)n clusters, especially for Fe-doped clusters.

  13. Structure, morphology and optical properties of undoped and MN-doped ZnO(1-x)Sx nano-powders prepared by precipitation method

    NASA Astrophysics Data System (ADS)

    Dejene, F. B.; Onani, M. O.; Koao, L. F.; Wako, A. H.; Motloung, S. V.; Yihunie, M. T.

    2016-01-01

    The undoped and Mn-doped ZnO(1-x)Sx nano-powders were successfully synthesized by precipitation method without using any capping agent. Its structure, morphology, elemental analysis, optical and luminescence properties were determined by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), UV-vis spectroscopy (UV) and photoluminescence spectroscopy (PL). A typical SEM image of the un-doped ZnO(1-x)Sx nanoparticles exhibit flake like structures that changes to nearly spherical particles with Mn-doping. The XRD of undoped and Mn doped ZnO(1-x)Sx pattern reveals the formation of a product indexed to the hexagonal wurtzite phase of ZnS. The nanopowders have crystallite sizes estimated from XRD measurements were in the range of 10-20 nm. All the samples showed absorption maximum of ZnO(1-x)Sx at 271 nm and high transmittance in UV and visible region, respectively. The undoped ZnO(1-x)Sx nanoparticles show strong room-temperature photoluminescence with four emission bands centering at 338 nm, 384 nm, 448 nm and 705 nm that may originate to the impurity of ZnO(1-x)Sx, existence of oxide related defects. The calculated bandgap of the nanocrystalline ZnO(1-x)Sx showed a blue-shift with respect to the Mn-doping. The PL spectra of the Mn-doped samples exhibit a strong orange emission at around 594 nm attributed to the 4T1-6A1 transition of the Mn2+ ions.

  14. Powder Materials and Energy Efficiency in Transportation: Opportunities and Challenges

    NASA Astrophysics Data System (ADS)

    Marquis, Fernand D. S.

    2012-03-01

    The transportation industry accounts for one quarter of global energy use and has by far the largest share of global oil consumption. It used 51.5% of the oil worldwide in 2003. Mobility projections show that it is expected to triple by 2050 with associated energy use. Considerable achievements recently have been obtained in the development of powder and powder-processed metallic alloys, metal matrix composites, intermetallics, and carbon fiber composites. These achievements have resulted in their introduction to the transportation industry in a wide variety of transportation components with significant impact on energy efficiency. A significant number of nano, nanostructured, and nanohybrid materials systems have been deployed. Others, some of them incorporating carbon nanotubes and graphene, are under research and development and exhibit considerable potential. Airplane redesign using a materials and functional systems integration approach was used resulting in considerable system improvements and energy efficiency. It is expected that this materials and functional systems integration soon will be adopted in the design and manufacture of other advanced aircrafts and extended to the automotive industry and then to the marine transportation industry. The opportunities for the development and application of new powder materials in the transportation industry are extensive, with considerable potential to impact energy utilization. However, significant challenges need to be overcome in several critical areas.

  15. Polyaniline nanowire array encapsulated in titania nanotubes as a superior electrode for supercapacitors.

    PubMed

    Xie, Keyu; Li, Jie; Lai, Yanqing; Zhang, Zhi'an; Liu, Yexiang; Zhang, Guoge; Huang, Haitao

    2011-05-01

    Conducting polymer with 1D nanostructure exhibits excellent electrochemical performances but a poor cyclability that limits its use in supercapacitors. In this work, a novel composite electrode made of polyaniline nanowire-titania nanotube array was synthesized via a simple and inexpensive electrochemical route by electropolymerizing aniline onto an anodized titania nanotube array. The specific capacitance was as high as 732 F g(-1) at 1 A g(-1), which remained at 543 F g(-1) when the current density was increased by 20 times. 74% of the maximum energy density (36.6 Wh kg(-1)) was maintained even at a high power density of 6000 W kg(-1). An excellent long cycle life of the electrode was observed with a retention of ∼86% of the initial specific capacitance after 2000 cycles. The good electrochemical performance was attributed to the unique microstructure of the electrode with disordered PANI nanowire arrays encapsulated inside the TiO(2) nanotubes, providing high surface area, fast diffusion path for ions and long-term cycle stability. Such a nanocomposite electrode is attractive for supercapacitor applications. © The Royal Society of Chemistry 2011

  16. Controlling Pu behavior on Titania: Implications for LEU Fission-Based Mo-99 Production

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Youker, Amanda J.; Brown, M. Alex; Heltemes, Thad A.

    Molybdenum-99 is the parent isotope of the most widely used isotope, technetium-99m, in all diagnostic nuclear medicine procedures. Due to proliferation concerns associated with the use of highly enriched uranium (HEU), the preferred method of fission-based Mo-99 production uses low enriched uranium (LEU) targets. Using LEU versus HEU for Mo-99 production produces similar to 30 times more Pu-239, due to neutron capture on U-238 to produce Np-239, which ultimately decays to Pu-239 (t(1/2) = 24,110 yr). Argonne National Laboratory is supporting a potential US Mo-99 producer in their efforts to produce Mo-99 from an LEU solution. In order to mitigatemore » the generation of large volumes of greater-than-class-C (GTCC) low level waste (Pu-239 concentrations greater than 1 nCi/g), we have focused our efforts on the separation chemistry of Pu and Mo with a titania sorbent in sulfate media. Results from batch and column experiments show that temperature and acid wash concentration can be used to control Pu behavior on titania.« less

  17. Effect of nano-packing on preservation quality of fresh strawberry (Fragaria ananassa Duch. cv Fengxiang) during storage at 4 degrees C.

    PubMed

    Yang, F M; Li, H M; Li, F; Xin, Z H; Zhao, L Y; Zheng, Y H; Hu, Q H

    2010-04-01

    A novel nano-packing material with lower relative humidity, oxygen transmission rate and high longitudinal strength was synthesized by blending polyethylene with nano-powder (nano-Ag, kaolin, anatase TiO(2), rutile TiO(2)), and its effect on preservation quality of strawberry fruits (Fragaria ananassa Duch. cv Fengxiang) was investigated during storage at 4 degrees C. Results showed that nano-packaging was able to maintain the sensory, physicochemical, and physiological quality of strawberry fruits at a higher level compared with the normal packing (polyethylene bags). After a 12-d storage, decreases in the contents of total soluble solids, titratable acidity, and ascorbic acid of nano-packing were significantly inhibited. Meanwhile, decay rate, anthocyanin, and malondialdehyde contents were decreased to 16.7%, 26.3 mg/100g, 66.3 micromol/g for nano-packing and 26.8%, 31.9 mg/100g, 75.4 micromol/g for normal packing; polyphenoloxidase (PPO) and pyrogallol peroxidase (POD) activities were significantly lower in nano-packing than the control. These data indicated that the nano-packaging might provide an attractive alternative to improve preservation quality of the strawberry fruits during extended storage. Nano-packing exhibited identified quality benefits applicable to the preservation of fresh strawberry. Furthermore, nano-packing has the advantages of simple processing and feasibility to be industrialized in contrast with other storages. Thus, the utilization of nano-packing will likely assist commercial producers and retailers in extending the shelf life of products over a broader range in the future.

  18. Characterisations Of Al{sub 2}O{sub 3}-13% Wt TiO{sub 2} Deposition On Mild Steel Via Plasma Spray Method

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Yusoff, N. H.; Isa, M. C.; Ghazali, M. J.

    2011-01-17

    To date, plasma sprayed alumina titania have been widely used as wear resistance coatings in textile, machinery and printing industries. Previous studies showed that the coating microstructures and properties were strongly depended on various parameters such as ceramic composition, grain size powders and spray parameters, thus, influencing the melting degree of the alumina titania during the deposition process. The aim of this study focuses on the evolution of the micron sizes of alumina-13%wt titania at different plasma spray power, ranging from 20kW to 40kW. It was noted that the coating porosity of alumina-13%wt titania were decreased from 6.2% to 4%more » by increasing the plasma power from 20 to 40 kW. At lower power value, partially melted powders were deposited, generating over 6% porosity within the microstructures. Percentage of porosity about 5.6% gave the best ratio of bi-modal structures, providing the highest microhardness value. Furthermore, the effect of microstructure and porosity formation on wear resistance was also discussed. Coatings with less porosity exhibited better resistance to wear, in which the wear resistance of coated mild steel possessed only {approx}5 x 10{sup -4} cm{sup 3}/Nm with 4% of porosity.« less

  19. Raman and dielectric studies of GdMnO3 bulk ceramics synthesized from nano powders

    NASA Astrophysics Data System (ADS)

    Samantaray, S.; Mishra, D. K.; Roul, B. K.

    2017-05-01

    Nanocrystalline GdMnO3 (GMO) powders has been synthesized by a simple chemical route i. e. pyrophoric reaction technique and then sintered in the form of bulk pellet at 850°C for 24 hours by adopting slow step sintering schedule. It is observed that by reducing the particles size, chemical route enhances the mixing process as well as decreasing the sintering temperature to get single phase material system in compared to the polycrystalline sample prepared directly from the micron sized commercial powder. Raman spectroscopic studies confirm that the sample is in single phase without any detectable impurity. Frequency dependent dielectric properties i.e., dielectric constant (K) and dielectric loss (tanδ) of GMO ceramics sintered at 850°C for 24 hours were studied at room temperature. The sample showed high K value (˜2736) in the frequency of 100 Hz at room temperature.

  20. Mechanical and thermal properties and morphological studies of 10 MeV electron beam irradiated LDPE/hydroxyapatite nano-composite

    NASA Astrophysics Data System (ADS)

    Soltani, Z.; Ziaie, F.; Ghaffari, M.; Afarideh, H.; Ehsani, M.

    2013-02-01

    In this work the nano-composite samples were prepared using the LDPE filled with different weight percentages of hydroxyapatite powder which was synthesized via hydrolysis method. The samples were subjected to irradiation under 10 MeV electron beam in 75-250 kGy doses. Mechanical and thermal properties as well as the morphology of the nano-composite samples were investigated and compared. The hot-set and swelling tests confirmed the radiation crosslinking induced in the polymer matrix especially between the matrix and reinforcement phase. The result indicates that the mechanical and thermal parameters are strongly dependent on the hydroxyapatite content in comparison to radiation.

  1. Influence of Starting Powders on Hydroxyapatite Coatings Fabricated by Room Temperature Spraying Method.

    PubMed

    Seo, Dong Seok; Lee, Jong Kook; Hwang, Kyu Hong; Hahn, Byung Dong; Yoon, Seog Young

    2015-08-01

    Three types of raw materials were used for the fabrication of hydroxyapatite coatings by using the room temperature spraying method and their influence on the microstructure and in vitro characteristics were investigated. Starting hydroxyapatite powders for coatings on titanium substrate were prepared by a heat treatment at 1100 °C for 2 h of bovine bone, bone ash, and commercial hydroxyapatite powders. The phase compositions and Ca/P ratios of the three hydroxyapatite coatings were similar to those of the raw materials without decomposition or formation of a new phase. All hydroxyapatite coatings showed a honeycomb structure, but their surface microstructures revealed different features in regards to surface morphology and roughness, based on the staring materials. All coatings consisted of nano-sized grains and had dense microstructure. Inferred from in vitro experiments in pure water, all coatings have a good dissolution-resistance and biostability in water.

  2. Bone-repair properties of biodegradable hydroxyapatite nano-rod superstructures

    NASA Astrophysics Data System (ADS)

    D'Elía, Noelia L.; Mathieu, Colleen; Hoemann, Caroline D.; Laiuppa, Juan A.; Santillán, Graciela E.; Messina, Paula V.

    2015-11-01

    for the in vitro conditions of bone-repair. Experiments are underway to investigate the effects of the material microstructure, surface roughness and hydrophilicity on their osseo-integration, osteo-conduction and osteo-induction abilities. Materials were tested in the presence of both, rat primary osteoblasts and rabbit mesenchymal stem cells. The following aspects are discussed: (i) cytotoxicity and material degradation; (ii) rat osteoblast spreading, proliferation and differentiation; and (iii) rabbit mesenchymal stem cell adhesion on nano-HAp and nano-HAp/collagen type I coatings. We effectively prepared a material based on biomimetic HAp nano-rods displaying the appropriate surface topography, hydrophilicity and degradation properties to induce the in vitro desired cellular responses for bone bonding and healing. Cells seeded on the selected material readily attached, proliferated and differentiated, as confirmed by cell viability, mitochondrial metabolic activity, alkaline phosphatase (ALP) activity and cytoskeletal integrity analysis by immunofluorescence localization of alpha-smooth muscle actin (α-SMA) protein. These results highlight the influence of material's surface characteristics to determine their tissue regeneration potential and their future use in engineering osteogenic scaffolds for orthopedic implants. Electronic supplementary information (ESI) available: Calculation of roughness parameters Rz, Rz,max, and Rz, prom. Nano-HAp powder degradation after immersion in phosphate buffer (pH = 7.4). Optical phase contrast microphotographs of MSC adhesion on nano-HAp and nano-HAp/Co I coatings at different concentrations. Laser scanning confocal microphotographs of MSCs' α-SMA expression spreading on large amounts of nano-HAp (MI) coatings. Immunofluorescence microphotograph analysis by image software. See DOI: 10.1039/c5nr04850h

  3. A MECHANISTIC MODEL FOR MERCURY CAPTURE WITH IN-SITU GENERATED TITANIA PARTICLES: ROLE OF WATER VAPOR

    EPA Science Inventory

    A mechanistic model to predict the capture of gas phase mercury species using in-situ generated titania nanosize particles activated by UV irradiation is developed. The model is an extension of a recently reported model1 for photochemical reactions that accounts for the rates of...

  4. Thermoelectric properties of nano-meso-micro β-MnO₂ powders as a function of electrical resistance

    DOE PAGES

    Hedden, Morgan; Francis, Nick; Haraldsen, Jason T.; ...

    2015-07-15

    Particle sizes of manganese oxide (β-MnO₂) powders were modified by using a mortar and pestle ground method for period of times that varied between 15–60 min. Particle size versus ground time clearly shows the existence of a size-induced regime transition (i.e., regime I and II). Thermoelectric properties of β-MnO₂ powders as a function of electrical resistance in the range of R P = 10 - 80Ω were measured. Based on the data presented, we propose a model for the β-MnO₂ system in which nanometer-scale MnO₂ crystallites bond together through weak van der Waals forces to form larger conglomerates that spanmore » in size from nanometer to micrometer scale.« less

  5. A new simple synthesis of CdS nano-particles by composite-molten-salt method and their high photocatalytic degradation activity

    NASA Astrophysics Data System (ADS)

    Xiang, Donghu; Zhu, Yabo; Cai, Cunjin; He, Zhanjun; Liu, Zhangsheng; Yin, Dagen; Luo, Jin

    2011-12-01

    Nano-CdS crystal has been succesfully synthesized by composite molten salt (CMS) method for the first time, using composite molten salt as a reaction solvent, sodium sulfide and cadmium nitrate hexahydrate as reactants at temperature of 200 °C for 24 h in the absence of organic dispersant or capping agents. X-ray diffraction and field emission scanning electron microscopy (FESEM) images indicated that the as-synthesized product were well crystallized and belonged to nano-scale. Their UV-vis absorption spectrum demonstrated a band gap of 2.49 eV corresponding to the absorption edge of 499 nm. The experimental result of photocatalytic degradation on methyl orange by the nano-CdS showed much better photocatalysis than that by the commercial CdS powder under the irradiation of ultraviolet light source.

  6. Synthesis of Silver Embedded Poly(o-Anisidine) Molybdophosphate Nano Hybrid Cation-Exchanger Applicable for Membrane Electrode

    PubMed Central

    Khan, Anish; Khan, Aftab Aslam Parwaz; Asiri, Abdullah M.; Rub, Malik Abdul

    2014-01-01

    Poly(o-anisidine) molybdophosphate was expediently obtained by sol-gel mixing of Poly(o-anisidine) into the inorganic matrices of molybdophosphate, which was allowed to react with silver nitrate to the formation of poly(o-anisidine) molybdophosphate embedded silver nano composite. The composite was characterized by Fourier Transform Infrared Spectroscopy, X-ray powder diffraction, UV-Vis Spectrophotometry, Fluorescence Spectroscopy, Scanning Electron Microscopy/Energy-dispersive X-ray Spectroscopy and Thermogravimertic Analysis. Ion exchange capacity and distribution studies were carried out to understand the ion-exchange capabilities of the nano composite. On the basis of highest distribution studies, this nano composite cation exchanger was used as preparation of heavy metal ion selective membrane. Membrane was characterized for its performance as porosity and swelling later on was used for the preparation of membrane electrode for Hg(II), having better linear range, wide working pH range (2–4.5) with fast response in the real environment. PMID:24805257

  7. Role of water and carbonates in photocatalytic transformation of CO{sub 2} to CH{sub 4} on titania.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Dimitrijevic, N. M.; Vijayan, B. K.; Poluektov, O. G.

    Using the electron paramagnetic resonance technique, we have elucidated the multiple roles of water and carbonates in the overall photocatalytic reduction of carbon dioxide to methane over titania nanoparticles. The formation of H atoms (reduction product) and {center_dot}OH radicals (oxidation product) from water, and CO{sub 3}{sup -} radical anions (oxidation product) from carbonates, was detected in CO{sub 2}-saturated titania aqueous dispersion under UV illumination. Additionally, methoxyl, {center_dot}OCH{sub 3}, and methyl, {center_dot}CH{sub 3}, radicals were identified as reaction intermediates. The two-electron, one-proton reaction proposed as an initial step in the reduction of CO{sub 2} on the surface of TiO{sub 2} ismore » supported by the results of first-principles calculations.« less

  8. Temperature dependent and applied field strength dependent magnetic study of cobalt nickel ferrite nano particles: Synthesized by an environmentally benign method

    NASA Astrophysics Data System (ADS)

    Sontu, Uday Bhasker; G, Narsinga Rao; Chou, F. C.; M, V. Ramana Reddy

    2018-04-01

    Spinel ferrites have come a long way in their versatile applications. The ever growing applications of these materials demand detailed study of material properties and environmental considerations in their synthesis. In this article, we report the effect of temperature and applied magnetic field strength on the magnetic behavior of the cobalt nickel ferrite nano powder samples. Basic structural properties of spinel ferrite nano particles, that are synthesized by an environmentally benign method of auto combustion, are characterized through XRD, TEM, RAMAN spectroscopy. Diffuse Reflectance Spectroscopy (DRS) is done to understand the nickel substitution effect on the optical properties of cobalt ferrite nano particles. Thermo magnetic studies using SQUID in the temperature range 5 K to 400 K and room temperature (300 K) VSM studies are performed on these samples. Fields of 0Oe (no applied field: ZF), 1 kOe (for ZFC and FC curves), 5 kOe (0.5 T), 50 kOe (5T) (for M-H loop study) are used to study the magnetic behavior of these nano particles. The XRD,TEM analysis suggest 40 nm crystallites that show changes in the cation distribution and phase changes in the spinel structure with nickel substitution. Raman micrographs support phase purity changes and cation redistributions with nickel substitution. Diffuse reflectance study on powder samples suggests two band gap values for nickel rich compounds. The Magnetic study of these sample nano particles show varied magnetic properties from that of hard magnetic, positive multi axial anisotropy and single-magnetic-domain structures at 5 K temperature to soft magnetic core shell like structures at 300 K temperature. Nickel substitution effect is non monotonous. Blocking temperature of all the samples is found to be higher than the values suggested in the literature.

  9. Modification of conventional glass-ionomer cements with N-vinylpyrrolidone containing polyacids, nano-hydroxy and fluoroapatite to improve mechanical properties.

    PubMed

    Moshaverinia, Alireza; Ansari, Sahar; Movasaghi, Zanyar; Billington, Richard W; Darr, Jawwad A; Rehman, Ihtesham U

    2008-10-01

    The objective of this study was to enhance the mechanical strength of glass-ionomer cements, while preserving their unique clinical properties. Copolymers incorporating several different segments including N-vinylpyrrolidone (NVP) in different molar ratios were synthesized. The synthesized polymers were copolymers of acrylic acid and NVP with side chains containing itaconic acid. In addition, nano-hydroxyapatite and fluoroapatite were synthesized using an ethanol-based sol-gel technique. The synthesized polymers were used in glass-ionomer cement formulations (Fuji II commercial GIC) and the synthesized nanoceramic particles (nano-hydroxy or fluoroapatite) were also incorporated into commercial glass-ionomer powder, respectively. The synthesized materials were characterized using FTIR and Raman spectroscopy and scanning electron microscopy. Compressive, diametral tensile and biaxial flexural strengths of the modified glass-ionomer cements were evaluated. After 24h setting, the NVP modified glass-ionomer cements exhibited higher compressive strength (163-167 MPa), higher diametral tensile strength (DTS) (13-17 MPa) and much higher biaxial flexural strength (23-26 MPa) in comparison to Fuji II GIC (160 MPa in CS, 12MPa in DTS and 15 MPa in biaxial flexural strength). The nano-hydroxyapatite/fluoroapatite added cements also exhibited higher CS (177-179 MPa), higher DTS (19-20 MPa) and much higher biaxial flexural strength (28-30 MPa) as compared to the control group. The highest values for CS, DTS and BFS were found for NVP-nanoceramic powder modified cements (184 MPa for CS, 22 MPa for DTS and 33 MPa for BFS) which were statistically higher than control group. It was concluded that, both NVP modified and nano-HA/FA added glass-ionomer cements are promising restorative dental materials with improved mechanical properties.

  10. Preparation and mechanical properties of carbon nanotube-silicon nitride nano-ceramic matrix composites

    NASA Astrophysics Data System (ADS)

    Tian, C. Y.; Jiang, H.

    2018-01-01

    Carbon nanotube-silicon nitride nano-ceramic matrix composites were fabricated by hot-pressing nano-sized Si3N4 powders and carbon nanotubes. The effect of CNTs on the mechanical properties of silicon nitride was researched. The phase compositions and the microstructure characteristics of the samples as well as the distribution of carbon nanotube in the silicon nitride ceramic were analyzed by X-ray diffraction and scanning electron microscope. The results show that the microstructure of composites consists mainly of α-Si3N4, β-Si3N4, Si2N2O and carbon natubes. The addition of proper amount of carbon nanotubes can improve the fracture toughness and the flexural strength, and the optimal amount of carbon nanotube are both 3wt.%. However the Vickers hardness values decrease with the increase of carbon nanotubes content.

  11. Validation of numerical simulations for nano-aluminum composite solid propellants

    NASA Astrophysics Data System (ADS)

    Yan, Allen H.

    2011-12-01

    Nano-aluminum is of interest as an energetic additive in composite solid propellant formulations for its demonstrated ability to increase combustion efficiency and burning rate. However, due to the current cost of nano-aluminum and the associated safety risks associated with propellant testing, it may not always be practical to spend the time and effort to mix, cast, and thoroughly evaluate the burning rate of a new formulation. To provide an alternative method of determining this parameter, numerical methods have been developed to predict the performance of nano-aluminum composite propellants, but these codes still require thorough validation before application. For this purpose, six propellant compositions were formulated, fully characterized, and burn rates were measured at several pressures between 34.0 and 129.3 atmospheres at room temperature, 20°C, and at an elevated temperature of 71.1°C in order to test the code's ability to predict pressure dependent burn rate and temperature sensitivity. To ensure the most accurate model possible, special emphasis was placed on characterizing the size distribution of the constituent nano-aluminum and ammonium perchlorate powders through optical diffraction or optical imaging techniques. Experimental burn rate is compared to the propellant combustion model and shows excellent agreement within 5% for a range of formulations and pressures, however under other conditions the model deviates by as much as 21%. An analysis of the results suggests that the current framework of the numerical model is unable to accurately simulate all the combustion physics of high aluminum content propellants, and suggestions for improvements are identified.

  12. Repair of bone defect by nano-modified white mineral trioxide aggregates in rabbit: A histopathological study.

    PubMed

    Saghiri, Mohammad-Ali; Orangi, Jafar; Tanideh, Nader; Asatourian, Armen; Janghorban, Kamal; Garcia-Godoy, Franklin; Sheibani, Nader

    2015-09-01

    Many researchers have tried to enhance materials functions in different aspects of science using nano-modification method, and in many cases the results have been encouraging. To evaluate the histopathological responses of the micro-/nano-size cement-type biomaterials derived from calcium silicate-based composition with addition of nano tricalcium aluminate (3CaO.Al2O3) on bone healing response. Ninety mature male rabbits were anesthetized and a bone defect was created in the right mandible. The rabbits were divided into three groups, which were in turn subdivided into five subgroups with six animals each based on the defect filled by: white mineral trioxide aggregate (WMTA), Nano-WMTA, WMTA without 3CaO.Al2O3, Nano-WMTA with 2% Nano-3CaO.Al2O3, and empty as control. Twenty, forty and sixty days postoperatively the animals were sacrificed and the right mandibles were removed for histopathological evaluations. Kruskal-Wallis test with post-hoc comparisons based on the LSMeans procedure was used for data analysis. All the experimental materials provoked a moderate to severe inflammatory reaction, which significantly differed from the control group (p< 0.05). Statistical analysis of bone formation and bone regeneration data showed significant differences between groups at 40- and 60- day intervals in all groups. Absence of 3CaO.Al2O3 leads to more inflammation and foreign body reaction than other groups in all time intervals. Both powder nano-modification and addition of 2% Nano-3CaO.Al2O3 to calcium silicate-based cement enhanced the favorable tissue response and osteogenesis properties of WMTA based materials.

  13. Synergistic combination dry powders for inhaled antimicrobial therapy

    NASA Astrophysics Data System (ADS)

    Heng, Desmond; Lee, Sie Huey; Teo, Jeanette; Ng, Wai Kiong; Chan, Hak-Kim; Tan, Reginald B. H.

    2013-06-01

    Combination products play an important role in medicine as they offer improved clinical effectiveness, enhanced patient adherence, and reduced administrative costs. In combination antimicrobial therapy, the desired outcome is to extend the antimicrobial spectrum and to achieve a possible synergistic effect. However, adverse antagonistic species may sometimes emerge from such combinations, leading to treatment failure. Therefore, it is crucial to screen the drug candidates for compatibility and possible antagonistic interactions. This work aims to develop a novel synergistic dry powder inhaler (DPI) formulation for antimicrobial combination therapy via the pulmonary route. Binary and ternary combinations were prepared via spray drying on a BUCHI® Nano Spray Dryer B-90. All powders were within the respirable size range, and were consisted of spherical particles that were slightly corrugated. The powers yielded fine particle fractions (of the loaded dose) of over 40% when dispersed using an Aerolizer® DPI at 60 L/min. Time-kill studies carried out against common respiratory tract pathogenic bacteria Pseudomonas aeruginosa, Staphylococcus aureus, Klebsiella pneumonia and Acinetobacter baumannii at 1x the minimum inhibitory concentration (MIC) over 24 hours revealed no antagonistic behavior for both combinations. While the interactions were generally found to be indifferent, a favorable synergistic effect was detected in the binary combination when it was tested against Pseudomonas aeruginosa bacteria.

  14. Effect of titanium on the structural and optical property of NiO nano powders

    NASA Astrophysics Data System (ADS)

    Amin, Ruhul; Mishra, Prashant; Khatun, Nasima; Ayaz, Saniya; Srivastava, Tulika; Sen, Somaditya

    2018-05-01

    Nickel Oxide (NiO) and Ti doped NiO nanoparticles were prepared by sol-gel auto combustion method. Powder x-ray diffraction (PXRD) structural studies revealed face centered cubic (FCC) structure of the NiO nanopowders. The crystallite size decreased with Ti incorporation. UV-Vis spectroscopy carried out in diffused reflectance mode revealed decrease in band gap with increment in Urbach energy with doping.

  15. A review on preparation of silver nano-particles

    NASA Astrophysics Data System (ADS)

    Haider, Adawiya J.; Haider, Mohammad J.; Mehde, Mohammad S.

    2018-05-01

    The term "nano particle" (NP) refers to particle diameter in nanometers in size. Nanoparticles contain a small number of constituent atoms or molecules that differ from the properties inherent in their bulk counterparts, found in various forms such as spherical, triangular, cubic, pentagonal, rod-shaped, shells, elliptical and so on. In this chapter, it has been presented the theoretical concepts of the preparation of AgNPS as powders and collide nanoparticles, techniques of preparation with their characterization (morphology, sign charge and potential value, particle distribution ….etc.). Also, included unique properties of AgNPS that are different from those of their bulk materials like: High surface area to volume ratio effects Quantization of electronic and vibration properties.

  16. SHMUTZ & PROTON-DIAMANT H + Irradiated/Written-Hyper/Super-conductivity(HC/SC) Precognizance/Early Experiments Connections: Wet-Graphite Room-Tc & Actualized MgB2 High-Tc: Connection to Mechanical Bulk-Moduli/Hardness: Diamond Hydrocarbon-Filaments, Disorder, Nano-Powders:C,Bi,TiB2,TiC

    NASA Astrophysics Data System (ADS)

    Wunderman, Irwin; Siegel, Edward Carl-Ludwig; Lewis, Thomas; Young, Frederic; Smith, Adolph; Dresschhoff-Zeller, Gieselle

    2013-03-01

    SHMUTZ: ``wet-graphite''Scheike-....[Adv.Mtls.(7/16/12)]hyper/super-SCHMUTZ-conductor(S!!!) = ``wet''(?)-``graphite''(?) = ``graphene''(?) = water(?) = hydrogen(?) =ultra-heavy proton-bands(???) = ...(???) claimed room/high-Tc/high-Jc superconductOR ``p''-``wave''/ BAND(!!!) superconductIVITY and actualized/ instantiated MgB2 high-Tc superconductors and their BCS- superconductivity: Tc Siegel[ICMAO(77);JMMM 7,190(78)] connection to SiegelJ.Nonxline-Sol.40,453(80)] disorder/amorphous-superconductivity in nano-powders mechanical bulk/shear(?)-moduli/hardness: proton-irradiated diamond, powders TiB2, TiC,{Siegel[Semis. & Insuls.5:39,47, 62 (79)])-...``VS''/concommitance with Siegel[Phys.Stat.Sol.(a)11,45(72)]-Dempsey [Phil.Mag. 8,86,285(63)]-Overhauser-(Little!!!)-Seitz-Smith-Zeller-Dreschoff-Antonoff-Young-...proton-``irradiated''/ implanted/ thermalized-in-(optimal: BOTH heat-capacity/heat-sink & insulator/maximal dielectric-constant) diamond: ``VS'' ``hambergite-borate-mineral transformable to Overhauser optimal-high-Tc-LiBD2 in Overhauser-(NW-periodic-table)-Land: CO2/CH4-ETERNAL-sequestration by-product: WATER!!!: physics lessons from

  17. Optimizing adsorption of blue pigment from wastewater by nano-porous modified Na-bentonite using spectrophotometry based on response surface method

    NASA Astrophysics Data System (ADS)

    Moradi, Neshat; Salem, Shiva; Salem, Amin

    2018-03-01

    This work highlighted the effective activation of bentonite paste to produce nano-porous powder for removal of cationic dye from wastewater. The effects of activation parameters such as soda and moisture contents, ageing time and temperature were analyzed using response surface methodology (RSM). The significance of independent variables and their interactions were tested by blending the obtained powders with wastewater and then the adsorption was evaluated, spectrophotometrically. The experiments were carried out by preparation of pastes according to response surface methodology and central composite design, which is the standard method, was used to evaluate the effects and interactions of four factors on the treatment efficiency. RSM was demonstrated as an appropriate approach for optimization of alkali activation. The optimal conditions obtained from the desirable responses were 5.0 wt% soda and 45.0 wt% moisture, respectively in which the powder activation was carried out at 150 °C. In order to well understand the role of nano-structured material on dye removal, the adsorbents were characterized through X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and Brunauer-Emmett-Teller surface area measurement. Finally, the analysis clearly demonstrates that the dye removal onto prepared adsorbent is well fitted with Langmuir isotherm compared to the other isotherm models. The low cost of material and facile process support the further development for commercial application purpose.

  18. Vacuum powder injector and method of impregnating fiber with powder

    NASA Astrophysics Data System (ADS)

    Working, Dennis C.

    1993-05-01

    A method and apparatus uniformly impregnate stranded material with dry powder such as low solubility, high melt flow polymer powder to produce, for example, composite prepregs. The stranded material is expanded in an impregnation chamber by an influx of air so that the powder, which may enter through the same inlet as the air, penetrates to the center of the stranded material. The stranded material then is contracted for holding the powder therein. The stranded material and powder may be pulled through the impregnation chamber in the same direction by vacuum. Larger particles of powder which do not fully penetrate the stranded material may be combed into the stranded material and powder which does not impregnate the stranded material may be collected and reused.

  19. Vacuum powder injector and method of impregnating fiber with powder

    NASA Technical Reports Server (NTRS)

    Working, Dennis C. (Inventor)

    1993-01-01

    A method and apparatus uniformly impregnate stranded material with dry powder such as low solubility, high melt flow polymer powder to produce, for example, composite prepregs. The stranded material is expanded in an impregnation chamber by an influx of air so that the powder, which may enter through the same inlet as the air, penetrates to the center of the stranded material. The stranded material then is contracted for holding the powder therein. The stranded material and powder may be pulled through the impregnation chamber in the same direction by vacuum. Larger particles of powder which do not fully penetrate the stranded material may be combed into the stranded material and powder which does not impregnate the stranded material may be collected and reused.

  20. Effect of Fe3O4 addition on dielectric properties of LaFeO3 nano-crystalline materials synthesized by sol-gel method

    NASA Astrophysics Data System (ADS)

    Laysandra, H.; Triyono, D.

    2017-04-01

    Dielectric properties of nano-crystalline material LaFeO3.xFe3O4 with x = 0, 0.1, 0.2, 0.3, and 0.4 at.% have been studied by impedance spectroscopy method. LaFeO3 was synthesized by sol-gel method resulting nano-particle. Then, it was mixed with Fe3O4 powder. The mixture powder was pressed to form pellet and then sintered at 1300°C for 1 h to form nano-crystalline of LaFeO3.xFe3O4. X-ray diffraction characterization at room temperature for all samples show two phases i.e. perovskite LaFeO3 (orthorhombic) as a main phase and Fe3O4 (cubic) as second phase. It is found that the crystallite size of main phase increases with addition of Fe3O4 until 0.3 at.%. The electrical properties as a function of temperature (300-500 K) and frequency (100 Hz - 1 MHz) are presented in Nyquist and Bode plots. It is observed that from equivalent circuit and their parameters, dielectrical properties are contributed by grain and grain boundary. The dielectric constant, ε‧ were calculated by parallel plate method and their values reach up to 107 exhibiting typical colossal dielectric constant (CDC) material like behavior.