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Sample records for nanostructured neodymium titanium

  1. Sol-Gel Synthesis and Characterization of Neodymium-Ion Doped Nanostructured Titania Thin Films

    DTIC Science & Technology

    2001-11-01

    ABSTRACT Nd doped TiO2 nanostructured thin films were prepared by sol - gel technique on quartz and Si substrates using TiCl 4 precursor. As-deposited...making TiO2 nanostructured thin films on quartz substrates via sol - gel method. The purpose of this study was to determine the effects of preparation...UNCLASSIFIED Defense Technical Information Center Compilation Part Notice ADP012201 TITLE: Sol - Gel Synthesis and Characterization of Neodymium-Ion

  2. Titanium nanostructures for biomedical applications.

    PubMed

    Kulkarni, M; Mazare, A; Gongadze, E; Perutkova, Š; Kralj-Iglič, V; Milošev, I; Schmuki, P; A Iglič; Mozetič, M

    2015-02-13

    Titanium and titanium alloys exhibit a unique combination of strength and biocompatibility, which enables their use in medical applications and accounts for their extensive use as implant materials in the last 50 years. Currently, a large amount of research is being carried out in order to determine the optimal surface topography for use in bioapplications, and thus the emphasis is on nanotechnology for biomedical applications. It was recently shown that titanium implants with rough surface topography and free energy increase osteoblast adhesion, maturation and subsequent bone formation. Furthermore, the adhesion of different cell lines to the surface of titanium implants is influenced by the surface characteristics of titanium; namely topography, charge distribution and chemistry. The present review article focuses on the specific nanotopography of titanium, i.e. titanium dioxide (TiO2) nanotubes, using a simple electrochemical anodisation method of the metallic substrate and other processes such as the hydrothermal or sol-gel template. One key advantage of using TiO2 nanotubes in cell interactions is based on the fact that TiO2 nanotube morphology is correlated with cell adhesion, spreading, growth and differentiation of mesenchymal stem cells, which were shown to be maximally induced on smaller diameter nanotubes (15 nm), but hindered on larger diameter (100 nm) tubes, leading to cell death and apoptosis. Research has supported the significance of nanotopography (TiO2 nanotube diameter) in cell adhesion and cell growth, and suggests that the mechanics of focal adhesion formation are similar among different cell types. As such, the present review will focus on perhaps the most spectacular and surprising one-dimensional structures and their unique biomedical applications for increased osseointegration, protein interaction and antibacterial properties.

  3. Titanium nanostructures for biomedical applications

    NASA Astrophysics Data System (ADS)

    Kulkarni, M.; Mazare, A.; Gongadze, E.; Perutkova, Š.; Kralj-Iglič, V.; Milošev, I.; Schmuki, P.; Iglič, A.; Mozetič, M.

    2015-02-01

    Titanium and titanium alloys exhibit a unique combination of strength and biocompatibility, which enables their use in medical applications and accounts for their extensive use as implant materials in the last 50 years. Currently, a large amount of research is being carried out in order to determine the optimal surface topography for use in bioapplications, and thus the emphasis is on nanotechnology for biomedical applications. It was recently shown that titanium implants with rough surface topography and free energy increase osteoblast adhesion, maturation and subsequent bone formation. Furthermore, the adhesion of different cell lines to the surface of titanium implants is influenced by the surface characteristics of titanium; namely topography, charge distribution and chemistry. The present review article focuses on the specific nanotopography of titanium, i.e. titanium dioxide (TiO2) nanotubes, using a simple electrochemical anodisation method of the metallic substrate and other processes such as the hydrothermal or sol-gel template. One key advantage of using TiO2 nanotubes in cell interactions is based on the fact that TiO2 nanotube morphology is correlated with cell adhesion, spreading, growth and differentiation of mesenchymal stem cells, which were shown to be maximally induced on smaller diameter nanotubes (15 nm), but hindered on larger diameter (100 nm) tubes, leading to cell death and apoptosis. Research has supported the significance of nanotopography (TiO2 nanotube diameter) in cell adhesion and cell growth, and suggests that the mechanics of focal adhesion formation are similar among different cell types. As such, the present review will focus on perhaps the most spectacular and surprising one-dimensional structures and their unique biomedical applications for increased osseointegration, protein interaction and antibacterial properties.

  4. Array of titanium dioxide nanostructures for solar energy utilization

    DOEpatents

    Qiu, Xiaofeng; Parans Paranthaman, Mariappan; Chi, Miaofang; Ivanov, Ilia N; Zhang, Zhenyu

    2014-12-30

    An array of titanium dioxide nanostructures for solar energy utilization includes a plurality of nanotubes, each nanotube including an outer layer coaxial with an inner layer, where the inner layer comprises p-type titanium dioxide and the outer layer comprises n-type titanium dioxide. An interface between the inner layer and the outer layer defines a p-n junction.

  5. Bi-phasic titanium dioxide nanoparticles doped with nitrogen and neodymium for enhanced photocatalysis

    NASA Astrophysics Data System (ADS)

    Gomez, Virginia; Bear, Joseph C.; McNaughter, Paul D.; McGettrick, James D.; Watson, Trystan; Charbonneau, Cecile; O'Brien, Paul; Barron, Andrew R.; Dunnill, Charles W.

    2015-10-01

    Bi-phasic or multi-phasic composite nanoparticles for use in photocatalysis have been produced by a new synthetic approach. Sol-gel methods are used to deposit multiple layers of active material onto soluble substrates. In this work, a layer of rutile (TiO2) was deposited onto sodium chloride pellets followed by an annealing step and a layer of anatase. After dissolving the substrate, bi-phasic nanoparticles containing half anatase and half rutile TiO2; with ``Janus-like'' characteristics are obtained. Nitrogen and neodymium doping of the materials were observed to enhance the photocatalytic properties both under UV and white light irradiation. The unique advantage of this synthetic method is the ability to systematically dope separate sides of the nanoparticles. Nitrogen doping was found to be most effective on the anatase side of the nanoparticle while neodymium was found to be most effective on the rutile side. Rhodamine B dye was effectively photodegraded by co-doped particles under white light.Bi-phasic or multi-phasic composite nanoparticles for use in photocatalysis have been produced by a new synthetic approach. Sol-gel methods are used to deposit multiple layers of active material onto soluble substrates. In this work, a layer of rutile (TiO2) was deposited onto sodium chloride pellets followed by an annealing step and a layer of anatase. After dissolving the substrate, bi-phasic nanoparticles containing half anatase and half rutile TiO2; with ``Janus-like'' characteristics are obtained. Nitrogen and neodymium doping of the materials were observed to enhance the photocatalytic properties both under UV and white light irradiation. The unique advantage of this synthetic method is the ability to systematically dope separate sides of the nanoparticles. Nitrogen doping was found to be most effective on the anatase side of the nanoparticle while neodymium was found to be most effective on the rutile side. Rhodamine B dye was effectively photodegraded by co

  6. Titanium nanostructural surface processing for improved biocompatibility

    SciTech Connect

    Cheng, H.-C.; Lee, S.-Y.; Chen, C.-C.; Shyng, Y.-C.; Ou, K.-L.

    2006-10-23

    X-ray photoelectron spectroscopy, grazing incident x-ray diffraction, transmission electron microscopy, and scanning electron microscopy were conducted to evaluate the effect of titanium hydride on the formation of nanoporous TiO{sub 2} on Ti during anodization. Nano-titanium-hydride was formed cathodically before anodizing and served as a sacrificial nanoprecipitate during anodization. Surface oxidation occurred and a multinanoporous structure formed after cathodic pretreatments followed by anodization treatment. The sacrificial nanoprecipitate is directly dissolved and the Ti transformed to nanoporous TiO{sub 2} by anodization. The formation of sacrificial nanoprecipitates by cathodic pretreatment and of the multinanostructure by anodization is believed to improve biocompatibility, thereby promoting osseointegration.

  7. Guided self-assembly of nanostructured titanium oxide

    NASA Astrophysics Data System (ADS)

    Wang, Baoxiang; Rozynek, Zbigniew; Fossum, Jon Otto; Knudsen, Kenneth D.; Yu, Yingda

    2012-02-01

    A series of nanostructured titanium oxide particles were synthesized by a simple wet chemical method and characterized by means of small-angle x-ray scattering (SAXS)/wide-angle x-ray scattering (WAXS), atomic force microscope (AFM), scanning electron microscope (SEM), transmission electron microscope (TEM), thermal analysis, and rheometry. Tetrabutyl titanate (TBT) and ethylene glycol (EG) can be combined to form either TiOx nanowires or smooth nanorods, and the molar ratio of TBT:EG determines which of these is obtained. Therefore, TiOx nanorods with a highly rough surface can be obtained by hydrolysis of TBT with the addition of cetyl-trimethyl-ammonium bromide (CTAB) as surfactant in an EG solution. Furthermore, TiOx nanorods with two sharp ends can be obtained by hydrolysis of TBT with the addition of salt (LiCl) in an EG solution. The AFM results show that the TiOx nanorods with rough surfaces are formed by the self-assembly of TiOx nanospheres. The electrorheological (ER) effect was investigated using a suspension of titanium oxide nanowires or nanorods dispersed in silicone oil. Oil suspensions of titanium oxide nanowires or nanorods exhibit a dramatic reorganization when submitted to a strong DC electric field and the particles aggregate to form chain-like structures along the direction of applied electric field. Two-dimensional SAXS images from chains of anisotropically shaped particles exhibit a marked asymmetry in the SAXS patterns, reflecting the preferential self-assembly of the particles in the field. The suspension of rough TiOx nanorods shows stronger ER properties than that of the other nanostructured TiOx particles. We find that the particle surface roughness plays an important role in modification of the dielectric properties and in the enhancement of the ER effect.

  8. Surface Engineering of Nanostructured Titanium Implants with Bioactive Ions.

    PubMed

    Kim, H-S; Kim, Y-J; Jang, J-H; Park, J-W

    2016-05-01

    Surface nanofeatures and bioactive ion chemical modification are centrally important in current titanium (Ti) oral implants for enhancing osseointegration. However, it is unclear whether the addition of bioactive ions definitively enhances the osteogenic capacity of a nanostructured Ti implant. We systematically investigated the osteogenesis process of human multipotent adipose stem cells triggered by bioactive ions in the nanostructured Ti implant surface. Here, we report that bioactive ion surface modification (calcium [Ca] or strontium [Sr]) and resultant ion release significantly increase osteogenic activity of the nanofeatured Ti surface. We for the first time demonstrate that ion modification actively induces focal adhesion development and expression of critical adhesion–related genes (vinculin, talin, and RHOA) of human multipotent adipose stem cells, resulting in enhanced osteogenic differentiation on the nanofeatured Ti surface. It is also suggested that fibronectin adsorption may have only a weak effect on early cellular events of mesenchymal stem cells (MSCs) at least in the case of the nanostructured Ti implant surface incorporating Sr. Moreover, results indicate that Sr overrides the effect of Ca and other important surface factors (i.e., surface area and wettability) in the osteogenesis function of various MSCs (derived from human adipose, bone marrow, and murine bone marrow). In addition, surface engineering of nanostructured Ti implants using Sr ions is expected to exert additional beneficial effects on implant bone healing through the proper balancing of the allocation of MSCs between adipogenesis and osteogenesis. This work provides insight into the future surface design of Ti dental implants using surface bioactive ion chemistry and nanotopography.

  9. Improving Osteoblast Response In Vitro by a Nanostructured Thin Film with Titanium Carbide and Titanium Oxides Clustered around Graphitic Carbon

    PubMed Central

    Longo, Giovanni; Ioannidu, Caterina Alexandra; Scotto d’Abusco, Anna; Superti, Fabiana; Misiano, Carlo; Zanoni, Robertino; Politi, Laura; Mazzola, Luca; Iosi, Francesca; Mura, Francesco; Scandurra, Roberto

    2016-01-01

    Introduction Recently, we introduced a new deposition method, based on Ion Plating Plasma Assisted technology, to coat titanium implants with a thin but hard nanostructured layer composed of titanium carbide and titanium oxides, clustered around graphitic carbon. The nanostructured layer has a double effect: protects the bulk titanium against the harsh conditions of biological tissues and in the same time has a stimulating action on osteoblasts. Results The aim of this work is to describe the biological effects of this layer on osteoblasts cultured in vitro. We demonstrate that the nanostructured layer causes an overexpression of many early genes correlated to proteins involved in bone turnover and an increase in the number of surface receptors for α3β1 integrin, talin, paxillin. Analyses at single-cell level, by scanning electron microscopy, atomic force microscopy, and single cell force spectroscopy, show how the proliferation, adhesion and spreading of cells cultured on coated titanium samples are higher than on uncoated titanium ones. Finally, the chemistry of the layer induces a better formation of blood clots and a higher number of adhered platelets, compared to the uncoated cases, and these are useful features to improve the speed of implant osseointegration. Conclusion In summary, the nanostructured TiC film, due to its physical and chemical properties, can be used to protect the implants and to improve their acceptance by the bone. PMID:27031101

  10. Tunable Nanostructures and Crystal Structures in Titanium Oxide Films

    PubMed Central

    2009-01-01

    Controllable nanostructures in spin coated titanium oxide (TiO2) films have been achieved by a very simple means, through change of post deposition annealing temperature. Electron beam imaging and reciprocal space analysis revealed as-deposited TiO2films to be characterized by a dominant anatase phase which converts to the rutile form at 600 °C and reverts to the anatase modification at 1,200 °C. The phase changes are also accompanied by changes in the film microstructure: from regular nanoparticles (as-deposited) to nanowires (600 °C) and finally to dendrite like shapes at 1,200 °C. Photoluminescence studies, Raman spectral results, and X-ray diffraction data also furnish evidence in support of the observed solid state phase transformations in TiO2. PMID:20596447

  11. Neodymium Magnets.

    ERIC Educational Resources Information Center

    Wida, Sam

    1992-01-01

    Uses extremely strong neodymium magnets to demonstrate several principles of physics including electromagnetic induction, Lenz's Law, domain theory, demagnetization, the Curie point, and magnetic flux lines. (MDH)

  12. Osseointegration is improved by coating titanium implants with a nanostructured thin film with titanium carbide and titanium oxides clustered around graphitic carbon.

    PubMed

    Veronesi, Francesca; Giavaresi, Gianluca; Fini, Milena; Longo, Giovanni; Ioannidu, Caterina Alexandra; Scotto d'Abusco, Anna; Superti, Fabiana; Panzini, Gianluca; Misiano, Carlo; Palattella, Alberto; Selleri, Paolo; Di Girolamo, Nicola; Garbarino, Viola; Politi, Laura; Scandurra, Roberto

    2017-01-01

    Titanium implants coated with a 500nm nanostructured layer, deposited by the Ion Plating Plasma Assisted (IPPA) technology, composed of 60% graphitic carbon, 25% titanium oxides and 15% titanium carbide were implanted into rabbit femurs whilst into the controlateral femurs uncoated titanium implants were inserted as control. At four time points the animals were injected with calcein green, xylenol orange, oxytetracycline and alizarin. After 2, 4 and 8weeks femurs were removed and processed for histology and static and dynamic histomorphometry for undecalcified bone processing into methylmethacrylate, sectioned, thinned, polished and stained with Toluidine blue and Fast green. The overall bone-implant contacts rate (percentage of bone-implant contacts/weeks) of the TiC coated implant was 1.6 fold than that of the uncoated titanium implant. The histomorphometric analyses confirmed the histological evaluations. More precisely, higher Mineral Apposition Rate (MAR, μm/day) (p<0.005) and Bone Formation Rate (BFR, μm(2)/μm/day) (p<0.0005) as well as Bone Implant Contact (Bic) and Bone Ingrowth values (p<0.0005) were observed for the TiC coated implants compared to uncoated implants. In conclusion the hard nanostructured TiC layer protects the bulk titanium implant against the harsh conditions of biological tissues and in the same time, stimulating adhesion, proliferation and activity of osteoblasts, induces a better bone-implant contacts of the implant compared to the uncoated titanium implant.

  13. Nanostructured severe plastic deformation processed titanium for orthodontic mini-implants.

    PubMed

    Serra, Glaucio; Morais, Liliane; Elias, Carlos Nelson; Semenova, Irina P; Valiev, Ruslan; Salimgareeva, Gulnaz; Pithon, Matheus; Lacerda, Rogério

    2013-10-01

    Titanium mini-implants have been successfully used as anchorage devices in Orthodontics. Commercially pure titanium (cpTi) was recently replaced by Ti-6Al-4V alloy as the mini-implant material base due to the higher strength properties of the alloy. However, the lower corrosion resistance and the lower biocompatibility have been lowering the success rate of Ti-6Al-4V mini-implants. Nanostructured titanium (nTi) is commercially pure titanium that was nanostructured by a specific technique of severe plastic deformation. It is bioinert, does not contain potentially toxic or allergic additives, and has higher specific strength properties than any other titanium applied in medical implants. The higher strength properties associated to the higher biocompatibility make nTi potentially useful for orthodontic mini-implant applications, theoretically overcoming cpTi and Ti-6Al-4V mini-implants. The purposes of the this work were to process nTi, to mechanically compare cpTi, Ti-6Al-4V, and nTi mini-implants by torque test, and to evaluate both the surface morphology and the fracture surface characteristics of them by SEM. Torque test results showed significant increase in the maximum torque resistance of nTi mini-implants when compared to cpTi mini-implants, and no statistical difference between Ti-6Al-4V and nTi mini-implants. SEM analysis demonstrated smooth surface morphology and transgranular fracture aspect for nTi mini-implants. Since nanostructured titanium mini-implants have mechanical properties comparable to titanium alloy mini-implants, and biocompatibility comparable to commercially pure titanium mini-implants, it is suggestive that nanostructured titanium can replace Ti-6Al-4V alloy as the material base for mini-implants.

  14. Yield stress and plasticity of nanostructured titanium of different purity at 300, 77, and 4.2 K

    SciTech Connect

    Tabachnikova, E. D. Bengus, V. Z.; Podol'skii, A. V.; Smirnov, S. N.; Valiev, R. Z.

    2009-11-15

    Specimens of nanostructured titanium with different dopant concentrations were prepared by intense plastic deformation via equal-channel-angular pressing. The low-temperature mechanical characteristics of the specimens subjected to active deformation under uniaxial tension and compression were studied. The yield stress and the limit uniform deformation of nanostructured and coarse-grained polycrystalline titanium were compared.

  15. Pyrolytic deposition of nanostructured titanium carbide coatings on the surface of multiwalled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Kremlev, K. V.; Ob"edkov, A. M.; Ketkov, S. Yu.; Kaverin, B. S.; Semenov, N. M.; Gusev, S. A.; Tatarskii, D. A.; Yunin, P. A.

    2016-05-01

    Nanostructured titanium carbide coatings have been deposited on the surface of multiwalled carbon nanotubes (MWCNTs) by the MOCVD method with bis(cyclopentadienyl)titanium dichloride precursor. The obtained TiC/MWCNT hybrid materials were characterized by X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy. It is established that a TiC coating deposits onto the MWCNT surface with the formation of a core-shell (MWSNT-TiC) type structure.

  16. Simple and fast annealing synthesis of titanium dioxide nanostructures and morphology transformation during annealing processes.

    PubMed

    Park, Jongbok; Ryu, Yeontack; Kim, Hansoo; Yu, Choongho

    2009-03-11

    Wire- and belt-like single-crystalline titanium dioxide nanostructures were synthesized by using a simple thermal annealing method, which has often been avoided for the synthesis of metal oxide nanostructures from high melting point metals such as Ti. The synthesis method requires neither high reaction temperature nor complicated reaction processes, and can be used for producing dense nanomaterials with relatively short reaction time at temperatures much lower than the melting point of titanium and titanium dioxide. Key synthesis factors including the choice of eutectic catalyst, growth temperature, and annealing time were systematically investigated. The synthesis reaction was promoted by a copper eutectic catalyst, producing long nanostructures with short reaction times. For example, it was observed that only 30 min of annealing time at 850 degrees C was enough to produce densely grown approximately 10 microm long nanowires with diameters of approximately 100 nm, and longer reaction time brought about morphology changes from wires to belts as well as producing longer nanostructures up to approximately 30 microm. The nanostructures have the crystalline rutile structure along the [Formula: see text] growth direction. Finally, our simple and effective method for the synthesis of TiO2 nanostructures could be utilized for growing other metal oxide nanowires from high melting temperature metals.

  17. NOVEL EMBEDDED CERAMIC ELECTRODE SYSTEM TO ACTIVATE NANOSTRUCTURED TITANIUM DIOXIDE FOR DEGRADATION OF MTBE

    EPA Science Inventory

    A novel reactor combining a flame-deposited nanostructured titanium dioxide film and a set of embedded ceramic electrodes was designed, developed and tested for degradation of methyl tert-butyl ether (MTBE) in water. On applying a voltage to the ceramic electrodes, a surface coro...

  18. Femtosecond laser induced periodic nanostructures on titanium dioxide film for improving biocompatibility

    NASA Astrophysics Data System (ADS)

    Shinonaga, T.; Horiguchi, N.; Tsukamoto, M.; Nagai, A.; Yamashita, K.; Hanawa, T.; Matsushita, N.; Guoqiang, X.; Abe, N.

    2013-03-01

    Periodic nanostructures formation on Titanium dioxide (TiO2) film by scanning of femtosecond laser beam spot at fundamental and second harmonic wave is reported. Titanium (Ti) is one of the most widely used for biomaterials, because of its excellent anti-corrosion and high mechanical properties. However, Ti implant is typically artificial materials and has no biofunction. Hence, it is necessary for improving the bioactivity of Ti. Recently, coating of TiO2 film on Ti plate surface is useful methods to improve biocompatibility of Ti plate. Then, if periodic nanostructures were formed on the film surface, cell spreading might be controlled at one direction. We propose periodic nanostructures formation on TiO2 film by femtosecond laser irradiation. Cell spread could be controlled along the grooves of periodic nanostructures. In the experiments, the film was formed on Ti plate with an aerosol beam. A commercial femtosecond Ti : sapphire laser system was employed in our experiments. Periodic nanostructures, lying perpendicular to the laser electric field polarization vector, were formed on the film at fundamental and second harmonic wave. Periodic nanostructures were also produced on Ti plate with femtosecond laser. The period of periodic nanostructures on the film was much shorter than that on Ti plate. By cell test, there was a region of cell spreading along the grooves of periodic nanostructures on the film formed with femtosecond laser at fundamental wave. On bare film surface, cell spreading was observed at all direction. These results suggest that direction of cell spread could be controlled by periodic nanostructures formation on the film.

  19. Synthesis and controllable wettability of micro- and nanostructured titanium phosphate thin films formed on titanium plates.

    PubMed

    Yada, Mitsunori; Inoue, Yuko; Sakamoto, Ayako; Torikai, Toshio; Watari, Takanori

    2014-05-28

    The hydrothermal treatment of a titanium plate in a mixed aqueous solution of hydrogen peroxide and aqueous phosphoric acid under different conditions results in the formation of various titanium phosphate thin films. The films have various crystal structures such as Ti2O3(H2PO4)2·2H2O, α-titanium phosphate (Ti(HPO4)2·H2O), π-titanium phosphate (Ti2O(PO4)2·H2O), or low-crystallinity titanium phosphate and different morphologies that have not been previously reported such as nanobelts, microflowers, nanosheets, nanorods, or nanoplates. The present study also suggests the mechanisms behind the formation of these thin films. The crystal structure and morphology of the titanium phosphate thin films depend strongly on the concentration of the aqueous hydrogen peroxide solution, the amount of phosphoric acid, and the reaction temperature. In particular, hydrogen peroxide plays an important role in the formation of the titanium phosphate thin films. Moreover, controllable wettability of the titanium phosphate thin films, including superhydrophilicity and superhydrophobicity, is reported. Superhydrophobic surfaces with controllable adhesion to water droplets are obtained on π-titanium phosphate nanorod thin films modified with alkylamine molecules. The adhesion force between a water droplet and the thin film depends on the alkyl chain length of the alkylamine and the duration of ultraviolet irradiation utilized for photocatalytic degradation.

  20. The design of novel nanostructures on titanium by solution chemistry for an improved osteoblast response

    NASA Astrophysics Data System (ADS)

    Divya Rani, V. V.; Manzoor, K.; Menon, Deepthy; Selvamurugan, N.; Nair, Shantikumar V.

    2009-05-01

    We report an interesting cell response to novel nanostructures formed on a titanium (Ti) surface by a simple non-lithographic bottom-up method. The surface topography of bio-implant materials dramatically influences their cell response. The aim of this study was to modify the surface of a titanium implant by a simple and cost effective processing technique and to determine its suitability for osteoblast attachment. A set of unique structures ranging from mesoporous nanoscaffolds, nanoflowers, nanoneedles, nanorods and octahedral bipyramids were fabricated by systematically tuning the hydrothermal conditions such as reaction medium composition, concentration, temperature and time duration. The cytotoxicity of surface modified Ti was assessed using human primary osteoblastic cells, and more than 90% of the cells were found to be viable after 24 h of incubation. Protein adsorption studies revealed that the surface modified nanostructures on titanium adsorbed more proteins, suggesting that they are capable of promoting cell adhesion/attachment. Immunofluorescence studies with vinculin antibody identified a distinctly different spread pattern of osteoblastic cells on hydrothermally modified nanostructured surfaces, indicating the formation of the focal adhesion points required for intracellular signaling. Thus, based on our results, we suggest that this study may present one of the best designs and systematic syntheses of biocompatible nanostructures on metallic Ti for orthopedic implant applications.

  1. Nanostructures and Lithium Electrochemical Reactivity of Lithium Titanites and Titanium Oxides: A Review

    SciTech Connect

    Yang, Zhenguo; Choi, Daiwon; Kerisit, Sebastien N.; Rosso, Kevin M.; Wang, Donghai; Zhang, Jiguang; Graff, Gordon L.; Liu, J.

    2009-07-15

    Being inherently safe and chemically compatible with the electrolyte, titanium oxidebased materials, including both Li-titanites and various TiO2-polymorphs, are considered alternatives to carbonaceous anodes in Li-ion batteries. Given the commercial success of the spinel lithium titanites, TiO2-polymorphs, in particular in nanostructured forms, have been fabricated and investigated for the applications. Nanostructuring leads to increased reaction areas, shortened Li+ diffusion and potentially enhanced solubility/capacity. Integration with an electron conductive second phase into the TiO2-based nanostructures eases the electron transport, resulting in further improved lithium electrochemical activity and the overall electrochemical performance. This paper reviews structural characteristics and Li-electrochemical reactivity, along with synthetic approaches, of nanostructures and nano-composites based on lithium titanites and TiO2-polymorphs that include rutile, anatase, bronze and brookite.

  2. Antibacterial and bioactive nanostructured titanium surfaces for bone integration

    NASA Astrophysics Data System (ADS)

    Ferraris, S.; Venturello, A.; Miola, M.; Cochis, A.; Rimondini, L.; Spriano, S.

    2014-08-01

    An effective and physiological bone integration and absence of bacterial infection are essential for a successful orthopaedic or dental implant. A titanium surface able to actively promote bone bonding and avoid microbial colonization represents an extremely interesting challenge for these purposes. An innovative and patented surface treatment focused on these issues is described in the present paper. It is based on acid etching and subsequent controlled oxidation in hydrogen peroxide, enriched with silver ions. It has been applied to commercially pure titanium (Ti-cp) and alloy Ti6Al4V. The chemistry and morphology of the surfaces are modified by the treatment on a nanoscale: they show a thin oxide layer with porosity on the nanoscale and silver particles (few nanometers in diameter), embedded in it. These features are effective in order to obtain antibacterial and bioactive titanium surfaces.

  3. Improving osseointegration of Co-Cr by nanostructured titanium coatings.

    PubMed

    Pham, Vuong-Hung

    2014-01-01

    This study reports the deposition of nanostructured Ti films on Co-Cr substrates to improve their surface characteristics and biocompatibility. The microstructure of the Ti films was controlled by application of negative substrate bias voltages. The surface roughness of Co-Cr implants was increased significantly after Ti coatings. The nanostructured Ti films are found to improve osteointergration of Co-Cr implants as indicated by enhancing cellular attachment, proliferation and differentiation, which was attributed mainly to the application of a biocompatible Ti coating, possessed a higher surface area for cell attachments and growth.

  4. Selective growth of palladium and titanium dioxide nanostructures inside carbon nanotube membranes

    PubMed Central

    2012-01-01

    Hybrid nanostructured arrays based on carbon nanotubes (CNT) and palladium or titanium dioxide materials have been synthesized using self-supported and silicon-supported anodized aluminum oxide (AAO) as nanoporous template. It is well demonstrated that carbon nanotubes can be grown using these membranes and hydrocarbon precursors that decompose at temperatures closer to 600°C without the use of a metal catalyst. In this process, carbonic fragments condensate to form stacked graphitic sheets, which adopt the shape of the pores, yielding from these moulds' multi-walled carbon nanotubes. After this process, the ends of the tubes remain open and accessible to other substances, whereas the outer walls are protected by the alumina. Taking advantage of this fact, we have performed the synthesis of palladium and titanium dioxide nanostructures selectively inside carbon nanotubes using these CNT-AAO membranes as nanoreactors. PMID:22731888

  5. Graphitic carbon in a nanostructured titanium oxycarbide thin film to improve implant osseointegration.

    PubMed

    Zanoni, R; Ioannidu, C A; Mazzola, L; Politi, L; Misiano, C; Longo, G; Falconieri, M; Scandurra, R

    2015-01-01

    A nanostructured coating layer on titanium implants, able to improve their integration into bones and to protect against the harsh conditions of body fluids, was obtained by Ion Plating Plasma Assisted, a method suitable for industrial applications. A titanium carbide target was attached under vacuum to a magnetron sputtering source powered with a direct current in the 500-1100 W range, and a 100 W radio frequency was applied to the sample holder. The samples produced at 900 W gave the best biological response in terms of overexpression of some genes of proteins involved in bone turnover. We report the characterization of a reference and of an implant sample, both obtained at 900 W. Different micro/nanoscopic techniques evidenced the morphology of the substrates, and X-ray Photoelectron Spectroscopy was used to disclose the surface composition. The layer is a 500 nm thick hard nanostructure, composed of 60% graphitic carbon clustered with 15% TiC and 25% Ti oxides.

  6. A low-cost hierarchical nanostructured beta-titanium alloy with high strength

    PubMed Central

    Devaraj, Arun; Joshi, Vineet V.; Srivastava, Ankit; Manandhar, Sandeep; Moxson, Vladimir; Duz, Volodymyr A.; Lavender, Curt

    2016-01-01

    Lightweighting of automobiles by use of novel low-cost, high strength-to-weight ratio structural materials can reduce the consumption of fossil fuels and in turn CO2 emission. Working towards this goal we achieved high strength in a low cost β-titanium alloy, Ti–1Al–8V–5Fe (Ti185), by hierarchical nanostructure consisting of homogenous distribution of micron-scale and nanoscale α-phase precipitates within the β-phase matrix. The sequence of phase transformation leading to this hierarchical nanostructure is explored using electron microscopy and atom probe tomography. Our results suggest that the high number density of nanoscale α-phase precipitates in the β-phase matrix is due to ω assisted nucleation of α resulting in high tensile strength, greater than any current commercial titanium alloy. Thus hierarchical nanostructured Ti185 serves as an excellent candidate for replacing costlier titanium alloys and other structural alloys for cost-effective lightweighting applications. PMID:27034109

  7. A low-cost hierarchical nanostructured beta-titanium alloy with high strength

    SciTech Connect

    Devaraj, Arun; Joshi, Vineet V.; Srivastava, Ankit; Manandhar, Sandeep; Moxson, Vladimir; Duz, Volodymyr A.; Lavender, Curt

    2016-04-01

    Lightweighting of automobiles by use of novel low-cost, high strength-to-weight ratio structural materials can reduce the consumption of fossil fuels and in turn CO2 emission. Working towards this goal we achieved high strength in a low cost β-titanium alloy, Ti-1Al-8V-5Fe (Ti185), by hierarchical nanostructure consisting of homogenous distribution of micron-scale and nanoscale α-phase precipitates within the β-phase matrix. The sequence of phase transformation leading to this hierarchical nanostructure is explored using electron microscopy and atom probe tomography. Our results suggest that the high number density of nanoscale α-phase precipitates in the β-phase matrix is due to ω assisted nucleation of α resulting in high tensile strength, greater than any current commercial titanium alloy. Furthermore hierarchical nanostructured Ti185 serves as an excellent candidate for replacing costlier titanium alloys and other structural alloys for cost-effective lightweighting applications.

  8. A low-cost hierarchical nanostructured beta-titanium alloy with high strength

    DOE PAGES

    Devaraj, Arun; Joshi, Vineet V.; Srivastava, Ankit; ...

    2016-04-01

    Lightweighting of automobiles by use of novel low-cost, high strength-to-weight ratio structural materials can reduce the consumption of fossil fuels and in turn CO2 emission. Working towards this goal we achieved high strength in a low cost β-titanium alloy, Ti-1Al-8V-5Fe (Ti185), by hierarchical nanostructure consisting of homogenous distribution of micron-scale and nanoscale α-phase precipitates within the β-phase matrix. The sequence of phase transformation leading to this hierarchical nanostructure is explored using electron microscopy and atom probe tomography. Our results suggest that the high number density of nanoscale α-phase precipitates in the β-phase matrix is due to ω assisted nucleation ofmore » α resulting in high tensile strength, greater than any current commercial titanium alloy. Furthermore hierarchical nanostructured Ti185 serves as an excellent candidate for replacing costlier titanium alloys and other structural alloys for cost-effective lightweighting applications.« less

  9. Fabrication of superhydrophilic nanostructured surface by thermal annealing of titanium thin films in air.

    PubMed

    Klamchuen, A; Pratontep, S

    2009-02-01

    We report on a novel approach to fabricate a superhydrophilic titanium oxynitride surface by dc magnetron sputtering deposition followed by thermal annealing in air. The annealing was conducted in a furnace with no gas control at temperature ranging from 300-700 degrees C. The chemical composition and the morphology of the films have been investigated by contact angle measurements, optical absorption spectroscopy, X-ray photoemission spectroscopy, transmission electron microscopy and atomic force microscopy. The results reveal that the annealed films consist of a 5-10 nm thick capping titanium composite layer on top of a titanium metal layer. The nitrogen and oxygen composition of this capping layer can be tailored with the annealing temperature. The annealing process also produces nanoscale protrusions on the surface, yielding water contact angles of less than five degrees. This annealing approach in air is a simple yet versatile method, capable of producing nanostructure materials with potential applications in photocatalytic coating and semiconductor fabrication.

  10. Biological insertion of nanostructured germanium and titanium oxides into diatom biosilica

    NASA Astrophysics Data System (ADS)

    Jeffryes, Clayton S.

    There is significant interest in titanium oxide and germanium-silicon oxide nanocomposites for optoelectronic, photocatalytic, and solar cell applications. The ability of the marine diatom Pinnularia sp. to uptake soluble metal oxides from cell culture medium, and incorporate them into the micro- and nano-structure of their amorphous silica cell walls, called frustules, was evaluated using an engineered photobioreactor system. The effects of metal oxides on the structural and elemental properties of the frustule were also evaluated. Diatom cell cultures grown in 5 L photobioreactors were initially charged with 0.5 mM of soluble silicon, Si(OH)4, an obligate substrate required for frustule fomation. Upon exhaustion of Si(OH)4 cells were exposed to the mixed pulse-addition of soluble silicon and germanium or co-perfusion addition of soluble silicon and titanium, which were incorporated into the frustules. Metals composition of the cell culture medium, diatom biomass and purified frustules were measured, as was the local elemental composition within the frustule pores and the metal oxide crystallinity. Diatom frustules having a germanium composition of 1.6 wt % were devoid of the native intra-pore structures and possessed enhanced photoluminescence and electroluminescence when compared to frustules without Ge. Diatoms cultivated in the presence of soluble titanium incorporated amorphous titania into the frustule, which maintained native structure even when local TiO2 concentrations within the nanopores approached 60 wt. %. Titanium oxide could also be biomimetically deposited directly within the diatom nanopores by adsorbing poly-L-lysine to the diatom biosilica where it catalyzed the soluble titanium precursor Ti-BALDH into amorphous titania nanoparticles. Both biogenic and biomimetic titania could be converted to anatase titanium by thermal annealing. It was determined that nanostructured metal oxide composites can be fabricated biomimetically or in cell culture to

  11. Tribocorrosion behaviour of nanostructured titanium substrates processed by high-pressure torsion.

    PubMed

    Faghihi, S; Li, D; Szpunar, J A

    2010-12-03

    Aseptic loosening induced by wear particles from artificial bearing materials is one of the main causes of malfunctioning in total hip replacements. With the increase in young and active patients, complications in revision surgeries and immense health care costs, there is considerable interest in wear-resistant materials that can endure longer in the harsh and corrosive body environment. Here, the tribological behaviour of nanostructured titanium substrates processed by high-pressure torsion (HPT) is investigated and compared with the coarse-grained samples. The high resolution transmission electron microscopy reveals that a nanostructured sample has a grain size of 5-10 nm compared to that of ∼ 10 µm and ∼ 50 µm for untreated and annealed substrates, respectively. Dry and wet wear tests were performed using a linear reciprocating ball-on-flat tribometer. Nanostructured samples show the best dry wear resistance and the lowest wear rate in the electrolyte. There was significantly lower plastic deformation and no change in preferred orientation of nanostructured samples attributable to the wear process. Electrochemical impedance spectroscopy (EIS) shows lower corrosion resistance for nanostructured samples. However, under the action of both wear and corrosion the nanostructured samples show superior performance and that makes them an attractive candidate for applications in which wear and corrosion act simultaneously.

  12. High-strength nanostructured titanium alloy for aerospace industry

    NASA Astrophysics Data System (ADS)

    Naydenkin, E. V.; Mishin, I. P.; Ratochka, I. V.; Vinokurov, V. A.

    2015-10-01

    The technological regimes of receiving of round bars of VT22 titanium alloy with the diameter 22 mm and hierarchically organized ultrafine-grained (nano-) structure by helical rolling and subsequent heat treatment (aging) were developed. It was shown that such structure formation results in a substantial increase (by more than 20%) of strength properties of the alloy as compared to the initial state. The obtained rods with a high specific strength may be used in the aerospace industry in the manufacture of critical structural elements.

  13. Electrically controlled drug release from nanostructured polypyrrole coated on titanium

    NASA Astrophysics Data System (ADS)

    Sirivisoot, Sirinrath; Pareta, Rajesh; Webster, Thomas J.

    2011-02-01

    Previous studies have demonstrated that multi-walled carbon nanotubes grown out of anodized nanotubular titanium (MWNT-Ti) can be used as a sensing electrode for various biomedical applications; such sensors detected the redox reactions of certain molecules, specifically proteins deposited by osteoblasts during extracellular matrix bone formation. Since it is known that polypyrrole (PPy) can release drugs upon electrical stimulation, in this study antibiotics (penicillin/streptomycin, P/S) or an anti-inflammatory drug (dexamethasone, Dex), termed PPy[P/S] or PPy[Dex], respectively, were electrodeposited in PPy on titanium. The objective of the present study was to determine if such drugs can be released from PPy on demand and (by applying a voltage) control cellular behavior important for orthopedic applications. Results showed that PPy films possessed nanometer-scale roughness as analyzed by atomic force microscopy. X-ray photoelectron spectroscopy confirmed the presence of P/S and Dex encapsulated within the PPy films. Results from cyclic voltammetry showed that 80% of the drugs were released on demand when sweep voltages were applied for five cycles at a scan rate of 0.1 V s - 1. Furthermore, osteoblast (bone-forming cells) and fibroblast (fibrous tissue-forming cells) adhesion were determined on the PPy films. Results showed that PPy[Dex] enhanced osteoblast adhesion after 4 h of culture compared to plain Ti. PPy-Ti (with or without anionic drug doping) inhibited fibroblast adhesion compared to plain Ti. These in vitro results confirmed that electrodeposited PPy[P/S] and PPy[Dex] can release drugs on demand to potentially fight bacterial infection, reduce inflammation, promote bone growth or reduce fibroblast functions, further implicating the use of such materials as implant sensors.

  14. Structure-related antibacterial activity of a titanium nanostructured surface fabricated by glancing angle sputter deposition

    NASA Astrophysics Data System (ADS)

    Sengstock, Christina; Lopian, Michael; Motemani, Yahya; Borgmann, Anna; Khare, Chinmay; Buenconsejo, Pio John S.; Schildhauer, Thomas A.; Ludwig, Alfred; Köller, Manfred

    2014-05-01

    The aim of this study was to reproduce the physico-mechanical antibacterial effect of the nanocolumnar cicada wing surface for metallic biomaterials by fabrication of titanium (Ti) nanocolumnar surfaces using glancing angle sputter deposition (GLAD). Nanocolumnar Ti thin films were fabricated by GLAD on silicon substrates. S. aureus as well as E. coli were incubated with nanostructured or reference dense Ti thin film test samples for one or three hours at 37 °C. Bacterial adherence, morphology, and viability were analyzed by fluorescence staining and scanning electron microscopy and compared to human mesenchymal stem cells (hMSCs). Bacterial adherence was not significantly different after short (1 h) incubation on the dense or the nanostructured Ti surface. In contrast to S. aureus the viability of E. coli was significantly decreased after 3 h on the nanostructured film compared to the dense film and was accompanied by an irregular morphology and a cell wall deformation. Cell adherence, spreading and viability of hMSCs were not altered on the nanostructured surface. The results show that the selective antibacterial effect of the cicada wing could be transferred to a nanostructured metallic biomaterial by mimicking the natural nanocolumnar topography.

  15. Structure-related antibacterial activity of a titanium nanostructured surface fabricated by glancing angle sputter deposition.

    PubMed

    Sengstock, Christina; Lopian, Michael; Motemani, Yahya; Borgmann, Anna; Khare, Chinmay; Buenconsejo, Pio John S; Schildhauer, Thomas A; Ludwig, Alfred; Köller, Manfred

    2014-05-16

    The aim of this study was to reproduce the physico-mechanical antibacterial effect of the nanocolumnar cicada wing surface for metallic biomaterials by fabrication of titanium (Ti) nanocolumnar surfaces using glancing angle sputter deposition (GLAD). Nanocolumnar Ti thin films were fabricated by GLAD on silicon substrates. S. aureus as well as E. coli were incubated with nanostructured or reference dense Ti thin film test samples for one or three hours at 37 °C. Bacterial adherence, morphology, and viability were analyzed by fluorescence staining and scanning electron microscopy and compared to human mesenchymal stem cells (hMSCs).Bacterial adherence was not significantly different after short (1 h) incubation on the dense or the nanostructured Ti surface. In contrast to S. aureus the viability of E. coli was significantly decreased after 3 h on the nanostructured film compared to the dense film and was accompanied by an irregular morphology and a cell wall deformation. Cell adherence, spreading and viability of hMSCs were not altered on the nanostructured surface. The results show that the selective antibacterial effect of the cicada wing could be transferred to a nanostructured metallic biomaterial by mimicking the natural nanocolumnar topography.

  16. Magnesium ion implantation on a micro/nanostructured titanium surface promotes its bioactivity and osteogenic differentiation function.

    PubMed

    Wang, Guifang; Li, Jinhua; Zhang, Wenjie; Xu, Lianyi; Pan, Hongya; Wen, Jin; Wu, Qianju; She, Wenjun; Jiao, Ting; Liu, Xuanyong; Jiang, Xinquan

    2014-01-01

    As one of the important ions associated with bone osseointegration, magnesium was incorporated into a micro/nanostructured titanium surface using a magnesium plasma immersion ion-implantation method. Hierarchical hybrid micro/nanostructured titanium surfaces followed by magnesium ion implantation for 30 minutes (Mg30) and hierarchical hybrid micro/nanostructured titanium surfaces followed by magnesium ion implantation for 60 minutes (Mg60) were used as test groups. The surface morphology, chemical properties, and amount of magnesium ions released were evaluated by field-emission scanning electron microscopy, energy dispersive X-ray spectroscopy, field-emission transmission electron microscopy, and inductively coupled plasma-optical emission spectrometry. Rat bone marrow mesenchymal stem cells (rBMMSCs) were used to evaluate cell responses, including proliferation, spreading, and osteogenic differentiation on the surface of the material or in their medium extraction. Greater increases in the spreading and proliferation ability of rBMMSCs were observed on the surfaces of magnesium-implanted micro/nanostructures compared with the control plates. Furthermore, the osteocalcin (OCN), osteopontin (OPN), and alkaline phosphatase (ALP) genes were upregulated on both surfaces and in their medium extractions. The enhanced cell responses were correlated with increasing concentrations of magnesium ions, indicating that the osteoblastic differentiation of rBMMSCs was stimulated through the magnesium ion function. The magnesium ion-implanted micro/nanostructured titanium surfaces could enhance the proliferation, spreading, and osteogenic differentiation activity of rBMMSCs, suggesting they have potential application in improving bone-titanium integration.

  17. Magnesium ion implantation on a micro/nanostructured titanium surface promotes its bioactivity and osteogenic differentiation function

    PubMed Central

    Wang, Guifang; Li, Jinhua; Zhang, Wenjie; Xu, Lianyi; Pan, Hongya; Wen, Jin; Wu, Qianju; She, Wenjun; Jiao, Ting; Liu, Xuanyong; Jiang, Xinquan

    2014-01-01

    As one of the important ions associated with bone osseointegration, magnesium was incorporated into a micro/nanostructured titanium surface using a magnesium plasma immersion ion-implantation method. Hierarchical hybrid micro/nanostructured titanium surfaces followed by magnesium ion implantation for 30 minutes (Mg30) and hierarchical hybrid micro/nanostructured titanium surfaces followed by magnesium ion implantation for 60 minutes (Mg60) were used as test groups. The surface morphology, chemical properties, and amount of magnesium ions released were evaluated by field-emission scanning electron microscopy, energy dispersive X-ray spectroscopy, field-emission transmission electron microscopy, and inductively coupled plasma-optical emission spectrometry. Rat bone marrow mesenchymal stem cells (rBMMSCs) were used to evaluate cell responses, including proliferation, spreading, and osteogenic differentiation on the surface of the material or in their medium extraction. Greater increases in the spreading and proliferation ability of rBMMSCs were observed on the surfaces of magnesium-implanted micro/nanostructures compared with the control plates. Furthermore, the osteocalcin (OCN), osteopontin (OPN), and alkaline phosphatase (ALP) genes were upregulated on both surfaces and in their medium extractions. The enhanced cell responses were correlated with increasing concentrations of magnesium ions, indicating that the osteoblastic differentiation of rBMMSCs was stimulated through the magnesium ion function. The magnesium ion-implanted micro/nanostructured titanium surfaces could enhance the proliferation, spreading, and osteogenic differentiation activity of rBMMSCs, suggesting they have potential application in improving bone-titanium integration. PMID:24940056

  18. Organic photovoltaic with various plasmonic nanostructures using titanium nitride

    NASA Astrophysics Data System (ADS)

    Magdi, Sara; Gan, Qiaoqiang; Swillam, Mohamed A.

    2016-03-01

    We demonstrate absorption improvement in organic solar cells due to the incorporation of TiN nanopatterned back electrode. Organic solar cells (OSC) have already reached 10% power conversion efficiency (PCE), which made them comparable to commercial solar cells. Localizing light using plasmonic nanostructures has the potential to overcome OSC absorption limitations and thus further improve their PCE. Using a C-MOS compatible, cheap and abundant material for light trapping could facilitate the commercialization of OSC. This work theoretically shows that the replacement of Ag nanopatterned back electrode with TiN in plasmonic OSC gives enhanced performance. In addition, the incorporation of TiN nanoparticles inside the active layer has been studied and analyzed.

  19. Synthesis of nanostructured porous silica coatings on titanium and their cell adhesive and osteogenic differentiation properties.

    PubMed

    Inzunza, Débora; Covarrubias, Cristian; Von Marttens, Alfredo; Leighton, Yerko; Carvajal, Juan Carlos; Valenzuela, Francisco; Díaz-Dosque, Mario; Méndez, Nicolás; Martínez, Constanza; Pino, Ana María; Rodríguez, Juan Pablo; Cáceres, Mónica; Smith, Patricio

    2014-01-01

    Nanostructured porous silica coatings were synthesized on titanium by the combined sol-gel and evaporation-induced self-assembly process. The silica-coating structures were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and nitrogen sorptometry. The effect of the nanoporous surface on apatite formation in simulated body fluid, protein adsorption, osteoblast cell adhesion behavior, and osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs) is reported. Silica coatings with highly ordered sub-10 nm porosity accelerate early osteoblast adhesive response, a favorable cell response that is attributed to an indirect effect due to the high protein adsorption observed on the large-specific surface area of the nanoporous coating but is also probably due to direct mechanical stimulus from the nanostructured topography. The nanoporous silica coatings, particularly those doped with calcium and phosphate, also promote the osteogenic differentiation of hBMSCs with spontaneous mineral nodule formation in basal conditions. The bioactive surface properties exhibited by the nanostructured porous silica coatings make these materials a promising alternative to improve the osseointegration properties of titanium dental implants and could have future impact on the nanoscale design of implant surfaces.

  20. Titanium-Catalyzed Silicon Nanostructures Grown by APCVD

    NASA Astrophysics Data System (ADS)

    Usman, Mohammad A. U.; Smith, Brady J.; Jackson, Justin B.; De Long, Matthew C.; Miller, Mark S.

    2015-01-01

    We report on growth of Ti-catalyzed silicon nanostructures (SNCs) through atmospheric-pressure chemical vapor deposition. An extensive growth study relating the growth condition parameters, including the partial pressure of SiCl4 gas, reaction temperature, and reaction time, was carried out to obtain insight into the growth regimes for the observed SNCs. Based on phase diagram analysis of Ti-Si alloy and growth rate analysis of the silicon nanowires (SNWs) and silicon nanoplatelets, we believe the growth mechanism to be strongly dependent on the thermodynamics of the system, exhibiting a delicate balance that can easily tip between the growth and etching regimes of the system. Three types of SNCs were observed frequently throughout the study: nanowires, nanoplatelets, and balls. Regimes for highly etched growth were also noted through growth conditions plots. Ti-catalyzed SNWs grown using SiCl4 gas strongly suggest growth occurring through a type of vapor-solid-solid (VSS) mechanism that is limited by diffusion through the solid-catalyst interface. On the other hand, the two-dimensional SNP morphologies suggest growth occurring through the twin-plane mechanism at the edges, at 10 nm to 100 nm scales, also through a similar, VSS mechanism.

  1. Electrospun Nanostructured Fibers of Collagen-Biomimetic Apatite on Titanium Alloy

    PubMed Central

    Iafisco, Michele; Foltran, Ismaela; Sabbatini, Simona; Tosi, Giorgio; Roveri, Norberto

    2012-01-01

    Titanium and its alloys are currently the mainly used materials to manufacture orthopaedic implants due to their excellent mechanical properties and corrosion resistance. Although these materials are bioinert, the improvement of biological properties (e.g., bone implant contact) can be obtained by the application of a material that mimics the bone extracellular matrix. To this aim, this work describes a new method to produce nanostructured collagen-apatite composites on titanium alloy substrate, by combining electrospinning and biomimetic mineralization. The characterization results showed that the obtained mineralized scaffolds have morphological, structural, and chemical compositional features similar to natural bone extracellular matrix. Finally, the topographic distribution of the chemical composition in the mineralized matrix evaluated by Fourier Transform Infrared microspectroscopy demonstrated that the apatite nanocrystals cover the collagen fibers assembled by the electrospinning. PMID:22400013

  2. Characteristics of titanium dioxide nanostructures synthesized via electrochemical anodization at different applied voltages

    SciTech Connect

    Cheong, Y. L.; Yam, F. K.; Hassan, Z.

    2015-05-15

    This paper presents the study of the growth of nanostructure titanium dioxide (TiO{sub 2}) via electrochemical anodization method. Both constant and alternating anodization voltage would be applied in this study. The effects of applied voltage on the morphological and structural properties were studied. Images of field emission scanning electron microscope (FE-SEM) revealed that morphology of nanostructure could be manipulated by changing the type and amount of applied voltage. Besides that, X-ray diffraction (XRD) results indicated that crystalline structures (anatase and rutile) could be obtained after being annealed at 700°C for 60 minutes. By analysing the data in XRD measurements, crystallite size of the TiO{sub 2} could be calculated by using the Scherrer method. Besides that, the relationship between mean crystallites sizes and anodization voltage would also be further studied in this paper.

  3. Formation of nanostructured TiO{sub 2} by femtosecond laser irradiation of titanium in O{sub 2}

    SciTech Connect

    Landis, Elizabeth C.; Phillips, Katherine C.; Mazur, Eric; Friend, Cynthia M.

    2012-09-15

    We used femtosecond laser irradiation of titanium metal in an oxidizing environment to form a highly stable surface layer of nanostructured amorphous titanium dioxide (TiO{sub 2}). We studied the influence of atmospheric composition on these surface structures and found that gas composition and pressure affect the chemical composition of the surface layer but not the surface morphology. Incorporation of nitrogen is only possible when no oxygen is present in the surrounding atmosphere.

  4. Nanostructured conducting polymers as intelligent implant surface: fabricated on biomedical titanium with a potential-induced reversible switch in wettability.

    PubMed

    Liao, Jingwen; Ning, Chengyun; Yin, Zhaoyi; Tan, Guoxin; Huang, Shishu; Zhou, Zhengnan; Chen, Junqi; Pan, Haobo

    2013-12-02

    Conducting polypyrrole (PPy) nanotube arrays, nanotube networks and irregular films are deposited on biomedical titanium. By in situ application of weak periodic potentials, the nanostructured conducting polymers undergo a reversible switch in wettability, which is a redox process of dopant molecules (as hydrophilic groups) immobilized and de-immobilized on the surface of the conducting polymers.

  5. Study on the Ohmic Contact, Electrical and Optical Properties of Nanostructured Titanium Dioxide Thin Films

    NASA Astrophysics Data System (ADS)

    Ahmad, M. K.; Rusop, M.

    2009-06-01

    Nanostructured Titanium Dioxide (TiO2) thin film with various sol-gel concentrations has been successfully prepared using sol-gel spin coating method. Nanostructured TiO2 thin films prepared at different sol-gel concentration from 0.1 M to 0.4 M. The IV measurement was measured using direct currents between two contacts were measured using Advantest source meter (R6243). To perform the IV measurement, two kinds of metal contact has been used; Platinum (Pt) and Gold (Au). It showed that both of metal contact shows that 0.2 M of concentration gives the lowest sheet resistance. The sheet resistance and resistivity of the thin film decreased from 0.1 M to 0.2 M and significantly increased at 0.3 M and 0.4 M. Optical transmission spectra were recorded in the wavelength range 200-1000 nm using UV-VIS-NIR Spectrophotometer (VARIAN 5000). The effect of sol concentration on band gap (Eg) values of the TiO2 thin films has been studied. The lowest band gap is 3.35 eV which contribute to 0.2 M of concentration and it is also understand that prepared nanostructured TiO2 thin film is indirect band gap.

  6. The response of human osteoblasts, epithelial cells, fibroblasts, macrophages and oral bacteria to nanostructured titanium surfaces: a systematic study

    PubMed Central

    Miao, Xinchao; Wang, Donghui; Xu, Lianyi; Wang, Jie; Zeng, Deliang; Lin, Shuxian; Huang, Cui; Liu, Xuanyong; Jiang, Xinquan

    2017-01-01

    Nanotopography modification is a major focus of interest in current titanium surface design; however, the influence of the nanostructured surface on human cell/bacterium behavior has rarely been systematically evaluated. In this study, a homogeneous nanofiber structure was prepared on a titanium surface (Nano) by alkali-hydrothermal treatment, and the effects of this Nano surface on the behaviors of human MG-63 osteoblasts, human gingival epithelial cells (HGECs) and human gingival fibroblasts (HGFs) were evaluated in comparison with a smooth titanium surface (Smooth) by polishing and a micro-rough titanium surface (Micro) by sandblasting and acid etching. In addition, the impacts of these different surface morphologies on human THP-1 macrophage polarization and Streptococcus mutans attachment were also assessed. Our findings showed that the nanostructured surface enhanced the osteogenic activity of MG-63 cells (Nano=Micro>Smooth) at the same time that it improved the attachment of HGECs (Nano>Smooth>Micro) and HGFs (Nano=Micro>Smooth). Furthermore, the surface with nanotexture did not affect macrophage polarization (Nano=Micro=Smooth), but did reduce initial bacterial adhesion (Nanonanostructured titanium surface may promote bone and soft tissue healing, and thereby increase the success and survival of dental implants. PMID:28260888

  7. Direct Blue Dye Degradation Using Titanium Nanostructures Under Energy-Efficient UV-LED Irradiation

    NASA Astrophysics Data System (ADS)

    Jo, Wan-Kuen; Tayade, Rajesh J.

    2016-01-01

    The present study describes the effect of titanium dioxide (TiO2) morphology on the photocatalytic activity under irradiation of ultraviolet light-emitting diode (UV-LED). Different TiO2 nanostructures were synthesized using hydrothermal (nanotubes and nanospheres) and solvothermal (nanoflowers) methods. The morphology, phase composition, bandgap, and chemical properties of the synthesized different TiO2 nanostructures were characterized using x-ray diffraction, scanning electron microscopy, transmission electron microscopy, ultraviolet visible diffuse reflectance spectroscopy (UV-Vis DRS), and Brunauer-Emmett-Teller (BET) analysis. The surface area of the nanotubes was larger than that of the nanospheres and nanoflowers by four- and three-fold, respectively. The photocatalytic activity of the photocatalysts was evaluated by degradation of direct blue-15 dye under UV-LED irradiation in a slurry-type reactor. The photocatalytic activity of the TiO2 nanoflowers was higher than that of TiO2 nanotubes or nanospheres, suggesting that nanoflowers can serve as efficient photocatalysts for dye degradation.

  8. Preparation and Photocatalytic Activity of Potassium-Incorporated Titanium Oxide Nanostructures Produced by the Wet Corrosion Process Using Various Titanium Alloys

    PubMed Central

    Lee, So Yoon; Lee, Choong Hyun; Kim, Do Yun; Locquet, Jean-Pierre; Seo, Jin Won

    2015-01-01

    Nanostructured potassium-incorporated Ti-based oxides have attracted much attention because the incorporated potassium can influence their structural and physico-chemical properties. With the aim of tuning the structural and physical properties, we have demonstrated the wet corrosion process (WCP) as a simple method for nanostructure fabrication using various Ti-based materials, namely Ti–6Al–4V alloy (TAV), Ti–Ni (TN) alloy and pure Ti, which have 90%, 50% and 100% initial Ti content, respectively. We have systematically investigated the relationship between the Ti content in the initial metal and the precise condition of WCP to control the structural and physical properties of the resulting nanostructures. The WCP treatment involved various concentrations of KOH solutions. The precise conditions for producing K-incorporated nanostructured titanium oxide films (nTOFs) were strongly dependent on the Ti content of the initial metal. Ti and TAV yielded one-dimensional nanowires of K-incorporated nTOFs after treatment with 10 mol/L-KOH solution, whereas TN required a higher concentration (20 mol/L-KOH solution) to produce comparable nanostructures. The obtained nanostructures revealed a blue-shift in UV absorption spectra due to the quantum confinement effects. A significant enhancement of the photocatalytic activity was observed via the chromomeric change and the intermediate formation of methylene blue molecules under UV irradiation. This study demonstrates the WCP as a simple, versatile and scalable method for the production of nanostructured K-incorporated nTOFs to be used as high-performance photocatalysts for environmental and energy applications. PMID:28347071

  9. Titanium

    SciTech Connect

    Fox, G.J.

    1997-01-01

    The article contains a summary of factors pertinent to titanium use. Geology and exploitation, production processes, global production, titanium dioxide and alloy applications, and the titanium market are reviewed. Potential applications outlined are for oil and gas equipment and for the automotive industry. Titanium alloys were selected for drilling risers for North Sea oil and gas drilling platforms due to a high strength-to-weight ratio and corrosion resistance. These properties also make titanium alloys attractive for auto parts, although the cost is currently prohibitive.

  10. Modulating macrophage polarization with divalent cations in nanostructured titanium implant surfaces

    NASA Astrophysics Data System (ADS)

    Lee, Chung-Ho; Kim, Youn-Jeong; Jang, Je-Hee; Park, Jin-Woo

    2016-02-01

    Nanoscale topographical modification and surface chemistry alteration using bioactive ions are centrally important processes in the current design of the surface of titanium (Ti) bone implants with enhanced bone healing capacity. Macrophages play a central role in the early tissue healing stage and their activity in response to the implant surface is known to affect the subsequent healing outcome. Thus, the positive modulation of macrophage phenotype polarization (i.e. towards the regenerative M2 rather than the inflammatory M1 phenotype) with a modified surface is essential for the osteogenesis funtion of Ti bone implants. However, relatively few advances have been made in terms of modulating the macrophage-centered early healing capacity in the surface design of Ti bone implants for the two important surface properties of nanotopography and and bioactive ion chemistry. We investigated whether surface bioactive ion modification exerts a definite beneficial effect on inducing regenerative M2 macrophage polarization when combined with the surface nanotopography of Ti. Our results indicate that nanoscale topographical modification and surface bioactive ion chemistry can positively modulate the macrophage phenotype in a Ti implant surface. To the best of our knowledge, this is the first demonstration that chemical surface modification using divalent cations (Ca and Sr) dramatically induces the regenerative M2 macrophage phenotype of J774.A1 cells in nanostructured Ti surfaces. In this study, divalent cation chemistry regulated the cell shape of adherent macrophages and markedly up-regulated M2 macrophage phenotype expression when combined with the nanostructured Ti surface. These results provide insight into the surface engineering of future Ti bone implants that are harmonized between the macrophage-governed early wound healing process and subsequent mesenchymal stem cell-centered osteogenesis function.

  11. In vitro and in vivo studies of osteoblast cell response to a titanium-6 aluminium-4 vanadium surface modified by neodymium:yttrium-aluminium-garnet laser and silicon carbide paper.

    PubMed

    Khosroshahi, M E; Mahmoodi, M; Saeedinasab, H

    2009-11-01

    The effects of neodymium:yttrium-aluminium-garnet (Nd:YAG) laser and silicon carbide (SiC) paper on the surface micro-topography of titanium-6 aluminium-4 vanadium (Ti6Al4V) alloy were examined in relation to the response of bone cells. The study was performed in three distinct stages: (1) after surface treatment of samples by laser and SiC paper, the surface hardness, surface roughness, corrosion resistance and surface tension were evaluated; (2) the growth of mouse connective tissue fibroblast cells (L-929) on untreated and treated samples was assessed in vitro; (3) the response of goat osteoblast cells to untreated and treated implanted samples was assessed in vivo. The surface roughness varied between 7 +/- 0.02 for laser-treated samples (LTSs) at 140 J cm(-2) and 21.8 +/- 0.05 for mechanically treated samples (MTSs). The surface hardness was found to vary from 377 Vickers hardness number (VHN) for MTSs to 850 VHN for LTSs. A corrosion potential of -0.21V was achieved for the LTSs compared with -0.51V for the MTSs. The LTSs exhibited a more hydrophilic behaviour (i.e. wettability) than did the MTSs. No cytotoxicity effect, unlike for the MTSs, was observed for the LTSs. The results of in vivo tests indicated longitudinal growth of osteoblast cells along the grooves on the samples formed by the SiC paper, and multidirectional spreading of the cells on the LTSs.

  12. Evaluating the osseointegration of nanostructured titanium implants in animal models: Current experimental methods and perspectives (Review).

    PubMed

    Babuska, Vaclav; Moztarzadeh, Omid; Kubikova, Tereza; Moztarzadeh, Amin; Hrusak, Daniel; Tonar, Zbynek

    2016-09-15

    The aim of this paper is to review the experimental methods currently being used to evaluate the osseointegration of nanostructured titanium implants using animal models. The material modifications are linked to the biocompatibility of various types of oral implants, such as laser-treated, acid-etched, plasma-coated, and sand-blasted surface modifications. The types of implants are reviewed according to their implantation site (endoosseous, subperiosteal, and transosseous implants). The animal species and target bones used in experimental implantology are carefully compared in terms of the ratio of compact to spongy bone. The surgical technique in animal experiments is briefly described, and all phases of the histological evaluation of osseointegration are described in detail, including harvesting tissue samples, processing undemineralized ground sections, and qualitative and quantitative histological assessment of the bone-implant interface. The results of histological staining methods used in implantology are illustrated and compared. A standardized and reproducible technique for stereological quantification of bone-implant contact is proposed and demonstrated. In conclusion, histological evaluation of the experimental osseointegration of dental implants requires careful selection of the experimental animals, bones, and implantation sites. It is also advisable to use larger animal models and older animals with a slower growth rate rather than small or growing experimental animals. Bones with a similar ratio of compact to spongy bone, such as the human maxilla and mandible, are preferred. A number of practical recommendations for the experimental procedures, harvesting of samples, tissue processing, and quantitative histological evaluations are provided.

  13. Titanium

    USGS Publications Warehouse

    Bedinger, G.M.

    2013-01-01

    Titanium is the ninth most abundant element in the earth’s crust and can be found in nearly all rocks and sediments. It is a lithophile element with a strong affinity for oxygen and is not found as a pure metal in nature. Titanium was first isolated as a pure metal in 1910, but it was not until 1948 that metal was produced commercially using the Kroll process (named after its developer, William Kroll) to reduce titanium tetrachloride with magnesium to produce titanium metal.

  14. Study on the Effect of Different Amount of Titanium Dioxide Nano-Powder to the Nano-Structured Titanium Dioxide Thin Films

    NASA Astrophysics Data System (ADS)

    Ahmad, M. K.; Rusop, M.

    2009-06-01

    Nanostructured Titanium Dioxide (TiO2) thin film with additional various amount of TiO2 nanopowder has been successfully prepared using sol-gel spin coating method. The amounts of TiO2 nanopowders are varied at 0.02 g, 0.04 g, 0.06 g, 0.08 g, 0.10 g and 0.12 g, respectively. The effects of different amount of Titanium Dioxide nanopowder to the structural, electrical and optical properties have been studied. The effects of different amount of nano-powder TiO2 were characterized using X-Ray Diffractometer (XRD), 2-point probe I-V measurement and UV-Vis-NIR Spectrophotometer. For electrical properties, O.1 g of TiO2 nanopowder gives the lowest sheet resistance among other nanostructured TiO2 thin film. As for XRD data, all thin films are in crystalline anatase form which can observe at 2θ degree 25.6° for [101]. As the amount TiO2 nanopowder increased at 0.10 g and 0.12 g, new crystalline anatase phase can be observed at 2θ degree 48.6° for [200]. All TiO2 thin films also exhibited optical transmittance over 69% with wavelength range from 200 nm to 1000 nm.

  15. Nitrogen-doped rice grain-shaped titanium dioxide nanostructures by electrospinning: Frequency and temperature dependent conductivity

    NASA Astrophysics Data System (ADS)

    Babu, Veluru Jagadeesh; Rao, Rayavarapu Prasada; Nair, A. Sreekumaran; Ramakrishna, Seeram

    2011-09-01

    Rice grain-shaped, nitrogen-doped titanium dioxide (N-TiO2) nanostructures are synthesized using sol-gel method and followed by electrospinning. The as-spun composite fibers are sintered at 500 °C for 1 h in air. SEM images of the sintered samples showed rice grain-shaped nanostructures. The nanostructures were made up of spherical nanoparticles with average diameters of ˜ 20 nm, and the average diameter decreased with increase of N doping level. The temperature and frequency dependent electrical characterization has carried on nanostructures using impedance spectroscopy in the range of 298 K to 498 K and 30 Hz to 7 MHz, respectively. The magnitude of the ac conductivity is obtained from Nyquist plots and is proved that the ac conductivity is strongly dependent on temperature. The activation energy (Ea) is obtained from Arrhenius plots, and it is lowered from 0.31 to 0.22 eV with increasing N content. Therefore, the rice-grain shaped nanostructures can be employed in the low temperature gas sensor applications.

  16. Enhanced osteoblast proliferation and corrosion resistance of commercially pure titanium through surface nanostructuring by ultrasonic shot peening and stress relieving.

    PubMed

    Jindal, Shitu; Bansal, Rajesh; Singh, Bijay P; Pandey, Rajiv; Narayanan, Shankar; Wani, Mohan R; Singh, Vakil

    2014-07-01

    This investigation was carried out to study the effect of a novel process of surface modification, surface nanostructuring by ultrasonic shot peening, on osteoblast proliferation and corrosion behavior of commercially pure titanium (c p-Ti) in simulated body fluid. A mechanically polished disc of c p-Ti was subjected to ultrasonic shot peening with stainless steel balls to create nanostructure at the surface. A nanostructure (<20 nm) with inhomogeneous distribution was revealed by atomic force and scanning electron microscopy. There was an increase of approximately 10% in cell proliferation, but there was drastic fall in corrosion resistance. Corrosion rate was increased by 327% in the shot peened condition. In order to examine the role of residual stresses associated with the shot peened surface on these aspects, a part of the shot peened specimen was annealed at 400°C for 1 hour. A marked influence of annealing treatment was observed on surface structure, cell proliferation, and corrosion resistance. Surface nanostructure was much more prominent, with increased number density and sharper grain boundaries; cell proliferation was enhanced to approximately 50% and corrosion rate was reduced by 86.2% and 41% as compared with that of the shot peened and the as received conditions, respectively. The highly significant improvement in cell proliferation, resulting from annealing of the shot peened specimen, was attributed to increased volume fraction of stabilized nanostructure, stress recovery, and crystallization of the oxide film. Increase in corrosion resistance from annealing of shot peened material was related to more effective passivation. Thus, the surface of c p-Ti, modified by this novel process, possessed a unique quality of enhancing cell proliferation as well as the corrosion resistance and could be highly effective in reducing treatment time of patients adopting dental and orthopedic implants of titanium and its alloys.

  17. Electron-beam-induced deposition and post-treatment processes to locally generate clean titanium oxide nanostructures on Si(100).

    PubMed

    Schirmer, M; Walz, M-M; Vollnhals, F; Lukasczyk, T; Sandmann, A; Chen, C; Steinrück, H-P; Marbach, H

    2011-02-25

    We have investigated the lithographic generation of TiO(x) nanostructures on Si(100) via electron-beam-induced deposition (EBID) of titanium tetraisopropoxide (TTIP) in ultra-high vacuum (UHV) by scanning electron microscopy (SEM) and local Auger electron spectroscopy (AES). In addition, the fabricated nanostructures were also characterized ex situ via atomic force microscopy (AFM) under ambient conditions. In EBID, a highly focused electron beam is used to locally decompose precursor molecules and thereby to generate a deposit. A drawback of this nanofabrication technique is the unintended deposition of material in the vicinity of the impact position of the primary electron beam due to so-called proximity effects. Herein, we present a post-treatment procedure to deplete the unintended deposits by moderate sputtering after the deposition process. Moreover, we were able to observe the formation of pure titanium oxide nanocrystals (<100 nm) in situ upon heating the sample in a well-defined oxygen atmosphere. While the nanocrystal growth for the as-deposited structures also occurs in the surroundings of the irradiated area due to proximity effects, it is limited to the pre-defined regions, if the sample was sputtered before heating the sample under oxygen atmosphere. The described two-step post-treatment procedure after EBID presents a new pathway for the fabrication of clean localized nanostructures.

  18. Electron-beam-induced deposition and post-treatment processes to locally generate clean titanium oxide nanostructures on Si(100)

    NASA Astrophysics Data System (ADS)

    Schirmer, M.; Walz, M.-M.; Vollnhals, F.; Lukasczyk, T.; Sandmann, A.; Chen, C.; Steinrück, H.-P.; Marbach, H.

    2011-02-01

    We have investigated the lithographic generation of TiOx nanostructures on Si(100) via electron-beam-induced deposition (EBID) of titanium tetraisopropoxide (TTIP) in ultra-high vacuum (UHV) by scanning electron microscopy (SEM) and local Auger electron spectroscopy (AES). In addition, the fabricated nanostructures were also characterized ex situ via atomic force microscopy (AFM) under ambient conditions. In EBID, a highly focused electron beam is used to locally decompose precursor molecules and thereby to generate a deposit. A drawback of this nanofabrication technique is the unintended deposition of material in the vicinity of the impact position of the primary electron beam due to so-called proximity effects. Herein, we present a post-treatment procedure to deplete the unintended deposits by moderate sputtering after the deposition process. Moreover, we were able to observe the formation of pure titanium oxide nanocrystals (<100 nm) in situ upon heating the sample in a well-defined oxygen atmosphere. While the nanocrystal growth for the as-deposited structures also occurs in the surroundings of the irradiated area due to proximity effects, it is limited to the pre-defined regions, if the sample was sputtered before heating the sample under oxygen atmosphere. The described two-step post-treatment procedure after EBID presents a new pathway for the fabrication of clean localized nanostructures.

  19. Metals Fact Sheet: Neodymium

    SciTech Connect

    1992-11-01

    Neodymium was discovered in 1898 when it was separated from {open_quotes}dydimium,{close_quotes} a praseodymium-neodymium compound that was thought to be only one element. {open_quotes}Neodymium{close_quotes} is derived from the Greek words {open_quotes}neos{close_quotes} and {open_quotes}didymos,{close_quotes} which translates to {open_quotes}new twin.{close_quotes} This article discusses sources and applications of the element, and reviews world reserves and demands. Price trends in the commodity are also noted.

  20. Self-assembled magnetic nanostructures: Epitaxial nickel on titanium nitride (001) surface

    NASA Astrophysics Data System (ADS)

    Zhou, Honghui

    2005-11-01

    Systems that contain single domain magnetic particles have been receiving intensive attentions over recent years since they are possible candidates for applications in ultrahigh-density data storage and magnetoelectronic devices. The focus of this research is self-assembly growth of magnetic nickel nanostructures by domain matching epitaxy under Volmer-Weber (V-W) mode. The growth was conducted by pulsed laser deposition (PLD) technique using epitaxial titanium nitride film as the template, which was in turn grown on silicon (100) substrate. The structural characterization includes X-ray diffraction and both cross-sectional and plan-view transmission electron microscopy. The results showed that the nickel islands formed exhibit a self-assembled nature, i.e., a certain degree of uniformity in orientation, shape, and size. The orientation relationship observed is Ni {100} // TiN {100} // Si {100}, the so-called "cube-on-cube" relationship. The islands are faceted, forming truncated pyramids with walls of (111) planes and a flat top of (100) plane. The base of islands is rectangular with the two principal edges parallel to two orthogonal <011> directions. The size distribution is relatively narrow, comparable to that obtained from self-assembled islands grown under Stranski-Krastanov (S-K) mode. A certain degree of self-organization was also found in the island lateral distribution: island chains were observed along the directions close to <011>, which are also the edge directions. The island faceting could be explained by surface energy minimization. The interaction of the island edge induced strain field between neighboring islands is believed to be responsible for the size uniformity and the lateral ordering. Magnetic measurements were also conducted on these crystallographically aligned nickel islands using superconducting quantum interference device (SQUID) magnetometer, and the results were compared with that obtained from the ensemble of randomly oriented

  1. Investigation of nanostructured platinum-nickel supported on the titanium surface as electrocatalysts for alkaline fuel cells

    NASA Astrophysics Data System (ADS)

    Tamašauskaitė-Tamašiūnaitė, L.; Balčiūnaitė, A.; Vaiciukevičienė, A.; Selskis, A.; Pakštas, V.

    2012-06-01

    This study involves the formation of nanostructured platinum-nickel supported on the titanium surface catalysts using the galvanic displacement technique and investigation of their electrocatalytic activity toward the oxidation of borohydride, methanol and ethanol in an alkaline media by cyclic voltammetry and chronoamperometry. Scanning electron microscopy, Energy Dispersive X-ray Spectroscopy and X-ray diffraction were used to characterize the surface structure, composition and morphology. The nanoPt(Ni)/Ti and nanoPt/Ti catalysts exhibited a higher catalytic efficiency to the oxidation of borohydride, ethanol and methanol as compared with that of pure Pt.

  2. Diagnostic features of relief formations on the nanostructured titanium VT1-0 surface after laser shock-wave treatment

    NASA Astrophysics Data System (ADS)

    Lytvynenko, I. V.; Lupenko, S. A.; Maruschak, P. O.; Panin, S. V.; Hats, Yu I.

    2017-02-01

    A new class of diagnostic features for conducting morphological analysis of relief formations induced by laser shock-wave treatment on the surface of the nanostructured titanium VT1-0 alloy is proposed. They are the coefficients of series expansions of statistical estimates for the orthogonal basis of Chebyshev, Laguerre, Kravchuk discrete polynomials and trigonometric functions. Based on the criterion of the minimum number of the diagnostic features in the above-mentioned bases, the Chebyshev one was selected as the most appropriate to solve this problem.

  3. Tungsten Bronze Barium Neodymium Titanate (Ba(6-3n)Nd(8+2n)Ti(18)O(54)): An Intrinsic Nanostructured Material and Its Defect Distribution.

    PubMed

    Azough, Feridoon; Cernik, Robert Joseph; Schaffer, Bernhard; Kepaptsoglou, Demie; Ramasse, Quentin Mathieu; Bigatti, Marco; Ali, Amir; MacLaren, Ian; Barthel, Juri; Molinari, Marco; Baran, Jakub Dominik; Parker, Stephen Charles; Freer, Robert

    2016-04-04

    We investigated the structure of the tungsten bronze barium neodymium titanates Ba(6-3n)Nd(8+2n)Ti(18)O(54), which are exploited as microwave dielectric ceramics. They form a complex nanostructure, which resembles a nanofilm with stacking layers of ∼12 Å thickness. The synthesized samples of Ba(6-3n)Nd(8+2n)Ti(18)O(54) (n = 0, 0.3, 0.4, 0.5) are characterized by pentagonal and tetragonal columns, where the A cations are distributed in three symmetrically inequivalent sites. Synchrotron X-ray diffraction and electron energy loss spectroscopy allowed for quantitative analysis of the site occupancy, which determines the defect distribution. This is corroborated by density functional theory calculations. Pentagonal columns are dominated by Ba, and tetragonal columns are dominated by Nd, although specific Nd sites exhibit significant concentrations of Ba. The data indicated significant elongation of the Ba columns in the pentagonal positions and of the Nd columns in tetragonal positions involving a zigzag arrangement of atoms along the b lattice direction. We found that the preferred Ba substitution occurs at Nd[3]/[4] followed by Nd[2] and Nd[1]/[5] sites, which is significantly different to that proposed in earlier studies. Our results on the Ba(6-3n)Nd(8+2n)Ti(18)O(54) "perovskite" superstructure and its defect distribution are particularly valuable in those applications where the optimization of material properties of oxides is imperative; these include not only microwave ceramics but also thermoelectric materials, where the nanostructure and the distribution of the dopants will reduce the thermal conductivity.

  4. Polarization of modified titanium and titanium-zirconium creates nano-structures while hydride formation is modulated

    NASA Astrophysics Data System (ADS)

    Frank, Matthias J.; Walter, Martin S.; Bucko, Miroslaw M.; Pamula, Elzbieta; Lyngstadaas, S. Petter; Haugen, Håvard J.

    2013-10-01

    The majority of titanium based bone-level dental implants available on the market today feature a sand-blasted and acid-etched (SBAE) surface that contains comparably high hydrogen levels. Cathodic polarization of titanium in acidic solutions is known to further increase titanium hydride on the surface. The aim of this study was to explore the effect of cathodic reduction on titanium (Ti) and titanium-zirconium (TiZr) with a SBAE surface in order to investigate the potential of such a process for further improving surfaces for bone anchored dental implants. Samples of both materials were cathodically polarized in acidic solution at different current densities and for different process times. Chemical analysis of the hydrogen levels by SIMS showed that cathodic reduction re-arranged the hydride already present on the surfaces from the etching process but could not significantly increase hydride levels. The hydrogen layer created by the preceding hot acid etching appeared to modulate further hydride creation. Analysis of the surface topography by SEM showed changes to the nano-topography of both materials after polarization. TiZr showed homogeneously distributed nano-spheres as they were already observed for TiZr SBAE at increased size of 80-100 nm on the whole surface. By contrast, polarization of Ti created nano-nodules and nano-spheres of 150-200 nm on the surface. These spheres were interconnected to form flower-like structures along the ridges and peaks of the surface. Moreover the flanks were covered by a rippled structure of isotropically distributed small-diameter (10-20 nm) nano-nodules.

  5. NanoCOT: Low-Cost Nanostructured Electrode Containing Carbon, Oxygen, and Titanium for Efficient Oxygen Evolution Reaction.

    PubMed

    Shan, Zhichao; Archana, Panikar Sathyaseelan; Shen, Gang; Gupta, Arunava; Bakker, Martin G; Pan, Shanlin

    2015-09-23

    Developing high-efficiency, durable, and low-cost catalysts based on earth-abundant elements for the oxygen evolution reaction (OER) is essential for renewable energy conversion and energy storage devices. In this study, we report a highly active nanostructured electrode, NanoCOT, which contains carbon, oxygen, and titanium, for efficient OER in alkaline solution. The NanoCOT electrode is synthesized from carbon transformation of TiO2 in an atmosphere of methane, hydrogen, and nitrogen at a high temperature. The NanoCOT exhibits enhanced OER catalytic activity in alkaline solution, providing a current density of 1.33 mA/cm(2) at an overpotential of 0.42 V. This OER current density of a NanoCOT electrode is about 4 times higher than an oxidized Ir electrode and 15 times higher than a Pt electrode because of its nanostructured high surface area and favorable OER kinetics. The enhanced catalytic activity of NanoCOT is attributed to the presence of a continuous energy band of the titanium oxide electrode with predominantly reduced defect states of Ti (e.g., Ti(1+), Ti(2+), and Ti(3+)) formed by chemical reduction with hydrogen and carbon. The OER performance of NanoCOT can also be further enhanced by decreasing its overpotential by 150 mV at a current density of 1.0 mA/cm(2) after coating its surface electrophoretically with 2.0 nm IrOx nanoparticles.

  6. Biofilm formation on nanostructured titanium oxide surfaces and a micro/nanofabrication-based preventive strategy using colloidal lithography.

    PubMed

    Singh, Ajay Vikram; Vyas, Varun; Salve, Tushar S; Cortelli, Daniele; Dellasega, David; Podestà, Alessandro; Milani, Paolo; Gade, W N

    2012-06-01

    The contamination of implant devices as a result of biofilm formation through bacterial infection has instigated major research in this area, particularly to understand the mechanism of bacterial cell/implant surface interactions and their preventions. In this paper, we demonstrate a controlled method of nanostructured titanium oxide surface synthesis using supersonic cluster beam depositions. The nanoscale surface characterization using atomic force microscopy and a profilometer display a regulated evolution in nanomorphology and physical properties. X-ray photoelectron spectroscopy analyses display a stoichiometric nanostructured TiO(2) film. Measurement of the water contact angle shows a nominal increase in the hydrophilic nature of ns-TiO(2) films, whereas the surface energy increases with decreasing contact angle. Bacterial species Staphylococcus aureus and Escherichia coli interaction with nanostructured surfaces shows an increase in adhesion and biofilm formation with increasing nanoscale morphological properties. Conversely, limiting ns-TiO(2) film distribution to micro/nanopatterned designed substrates integrated with bovine serum albumin functionalization leads to a reduction in biofilm formations due to a globally decreased bacterial cell-surface interaction area. The results have potential implications in inhibiting bacterial colonization and promoting mammalian cell-implant interactions.

  7. Formation and bioactivity of porous and nanostructured TiO2/beta-TCP coating on titanium.

    PubMed

    Hu, Hongjie; Liu, Xuanyong; Meng, Fanhao; Ding, Chuanxian

    2011-12-01

    Titanium and its alloys have been widely used as hard tissue implants due to their excellent mechanical properties and biocompatibility. However, their near bio-inertness and metallic ion release are still the problems with clinical uses. In this paper, porous and nanostructured TiO2/beta-tricalcium phosphate (beta-TCP) composite coatings were prepared on titanium substrates by plasma electrolytic oxidation (PEO) in a Ca and P-containing electrolyte. The influence of PEO electric current density on phase composition and bioactivity of the coatings were studied. X-ray diffraction, scanning electron microscopy and Fourier transfer infrared spectroscopy were utilized to characterize the phase composition and microstructure of the coatings. Simulated body fluid immersion tests were employed on the coatings to evaluate their bioactivity. The results reveal that TiO2/beta-TCP composite coating with pores size less than 10 microm and grains of 50-100 nm in size was prepared. The electric current density of PEO is an important factor in the formation of the composite coating. The TiO2/beta-TCP composite coating shows good bioactivity, which are attributed to the incorporation of beta-TCP.

  8. Monolithic co-aerogels of carbon/titanium dioxide as three dimensional nanostructured electrodes for energy storage

    NASA Astrophysics Data System (ADS)

    Yang, Sungwoo; Cai, Yue; Cheng, Yingwen; Varanasi, C. V.; Liu, Jie

    2012-11-01

    Conductive fillers, such as amorphous carbon, carbon nanotube and graphene etc., are generally mixed with nanostructured metal oxide materials to improve the performance of electrode materials in energy storage devices. However, the conductive framework that provides path for electric conduction does not normally form a well-connected and robust 3-D network to ensure optimized ions transport. Here, we report a convenient, inexpensive and scalable method for synthesizing hybrid carbon and titanium dioxide co-gels and co-aerogels to improve the electrochemical capacity by combining both the lithium insertion and the surface storage mechanisms in Li ion batteries (LIBs) anodes. A monolithic piece of a hybrid C/TiO2 co-aerogel can be directly used as an active electrode without the addition of binders, such as polyvinylidene fluoride (PVDF). As a result, the performance of LIB anodes using the hybrid co-aerogel is significantly improved over current LIBs based on carbon/titanium oxide composites. The reversible discharge capacity was stabilized at ˜400 mAh g-1 at a 168 mA g-1 scan rate and an operating voltage between 3.0 and 0.05 V vs. Li+/Li with excellent cyclic capacity retention. This approach, however, is not limited to only C/TiO2 system but can be extended to other metal oxides to form co-gels with carbon to improve their potential use in numerous electrochemical, photocatalytic, and photoelectronic devices.

  9. Increased endothelial and vascular smooth muscle cell adhesion on nanostructured titanium and CoCrMo

    PubMed Central

    Choudhary, Saba; Berhe, Mikal; Haberstroh, Karen M; Webster, Thomas J

    2006-01-01

    In the body, vascular cells continuously interact with tissues that possess nanostructured surface features due to the presence of proteins (such as collagen and elastin) embedded in the vascular wall. Despite this fact, vascular stents intended to restore blood flow do not have nanoscale surface features but rather are smooth at the nanoscale. As the first step towards creating the next generation of vascular stent materials, the objective of this in vitro study was to investigate vascular cell (specifically, endothelial, and vascular smooth muscle cell) adhesion on nanostructured compared with conventional commercially pure (cp) Ti and CoCrMo. Nanostructured cp Ti and CoCrMo compacts were created by separately utilizing either constituent cp Ti or CoCrMo nanoparticles as opposed to conventional micronsized particles. Results of this study showed for the first time increased endothelial and vascular smooth muscle cell adhesion on nanostructured compared with conventional cp Ti and CoCrMo after 4 hours’ adhesion. Moreover, compared with their respective conventional counterparts, the ratio of endothelial to vascular smooth muscle cells increased on nanostructured cp Ti and CoCrMo. In addition, endothelial and vascular smooth muscle cells had a better spread morphology on the nanostructured metals compared with conventional metals. Overall, vascular cell adhesion was better on CoCrMo than on cp Ti. Results of surface characterization studies demonstrated similar chemistry but significantly greater root-mean-square (rms) surface roughness as measured by atomic force microscopy (AFM) for nanostructured compared with respective conventional metals. For these reasons, results from the present in vitro study provided evidence that vascular stents composed of nanometer compared with micron-sized metal particles (specifically, either cp Ti or CoCrMo) may invoke cellular responses promising for improved vascular stent applications. PMID:17722261

  10. Nanostructured titanium-silver coatings with good antibacterial activity and cytocompatibility fabricated by one-step magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Bai, Long; Hang, Ruiqiang; Gao, Ang; Zhang, Xiangyu; Huang, Xiaobo; Wang, Yueyue; Tang, Bin; Zhao, Lingzhou; Chu, Paul K.

    2015-11-01

    Bacterial infection and loosing are serious complications for biomedical implants in the orthopedic, dental, and other biomedical fields and the ideal implants should combine good antibacterial ability and bioactivity. In this study, nanostructured titanium-silver (Ti-Ag) coatings with different Ag contents (1.2 to 21.6 at%) are prepared on Ti substrates by magnetron sputtering. As the Ag concentration is increased, the coatings change from having dense columnar crystals to sparse ones and eventually no columnar structure. The Ti-Ag coatings can effectively kill Staphylococcus aureus during the first few days and remain moderately antibacterial after immersion for 75 days. Compared to pure Ti, the Ti-Ag coatings show good cytocompatibility as indicated by good osteoblast adhesion, proliferation, intracellular total protein synthesis, and alkaline phosphatase (ALP) activity. In addition, cell spreading, collagen secretion, and extracellular matrix mineralization are promoted on the coatings with the proper Ag contents due to the nanostructured morphological features. Our results indicate that favorable antibacterial activity and osseointegration ability can be simultaneously achieved by regulating the Ag contents in Ti-Ag coatings.

  11. Nanostructured Titanium Oxide Film- And Membrane-Based Photocatalysis For Water Treatment

    EPA Science Inventory

    Titanium Oxide (TiO2) photocatalysis, one of the ultraviolet (UV)-based advanced oxidation technologies (AOTs) and nanotechnologies (AONs), has attracted great attention for the development of efficient water treatment and purification systems due to the effectiveness ...

  12. Enhanced apatite-forming ability and cytocompatibility of porous and nanostructured TiO2/CaSiO3 coating on titanium.

    PubMed

    Hu, Hongjie; Qiao, Yuqin; Meng, Fanhao; Liu, Xuanyong; Ding, Chuanxian

    2013-01-01

    To improve the bioactivity and cytocompatibility of biomedical titanium dioxide coating, many efforts have been made to modify its surface composition and topography. Meanwhile, CaSiO(3) was commonly investigated as coating material on titanium implants for fast fixation and firm implant-bone attachment due to its demonstrated bioactivity and osteointegration. In this work, gradient TiO(2)/CaSiO(3) coating on titanium was prepared by a two-step procedure, in which porous and nanostructured TiO(2) coating on titanium was prepared by plasma electrolytic oxidation in advance, and then needle and flake-like CaSiO(3) nanocrystals were deposited on the TiO(2) coating surface by electron beam evaporation. In view of the potential clinical applications, apatite-forming ability of the TiO(2)/CaSiO(3) coating was evaluated by simulated body fluid (SBF) immersion tests, and MG63 cells were cultured on the surface of the coating to investigate its cytocompatibility. The results show that deposition of CaSiO(3) significantly enhanced the apatite-forming ability of nanostructured TiO(2) coating in SBF. Meanwhile, the MG63 cells on TiO(2)/CaSiO(3) coating show higher proliferation rate and vitality than that on TiO(2) coating. In conclusion, the porous and nanostructured TiO(2)/CaSiO(3) coating on titanium substrate with good apatite-forming ability and cytocompatibility is a potential candidate for bone tissue engineering and implant coating.

  13. Synthesis and characterization of nanostructured titanium carbide for fuel cell applications

    NASA Astrophysics Data System (ADS)

    Singh, Paviter; Singh, Harwinder; Singh, Bikramjeet; Kaur, Manpreet; Kaur, Gurpreet; Kumar, Manjeet; Bala, Rajni; Kumar, Akshay

    2016-04-01

    Titanium carbide (TiC) nanoparticles have been successfully synthesized by carbo-thermic reaction of titanium and acetone at 800 °C. This method is relatively low temperature synthesis route. It can be used for large scale production of TiC. The synthesized nanoparticles have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and differential thermal analyzer (DTA) techniques. XRD analysis confirmed the formation of single phase TiC. XRD analysis confirmed that the particles are spherical in shape with an average particle size of 13 nm. DTA analysis shows that the phase is stable upto 900 °C and the material can be used for high temperature applications.

  14. Cracks growth behaviors of commercial pure titanium under nanosecond laser irradiation for formation of nanostructure-covered microstructures (with sub-5-μm)

    NASA Astrophysics Data System (ADS)

    Pan, A. F.; Wang, W. J.; Mei, X. S.; Zheng, B. X.; Yan, Z. X.

    2016-11-01

    This study reported on the formation of sub-5-μm microstructures covered on titanium by cracks growth under 10-ns laser radiation at the wavelength of 532 nm and its induced light modification for production of nanostructures. The electric field intensity and laser power density absorbed by commercial pure titanium were computed to investigate the self-trapping introduced by cracks and the effect of surface morphology on laser propagation characteristics. It is found that nanostructures can form at the surface with the curvature radius below 20 μm. Meanwhile, variable laser fluences were applied to explore the evolution of cracks on commercial pure titanium with or without melt as spot overlap number increased. Experimental study was first performed at the peak laser fluence of 1.063 J/cm2 to investigate the microstructures induced only by cracks growth. The results demonstrated that angular microstructures with size between 1.68 μm and 4.74 μm was obtained and no nanostructure covered. Then, at the peak laser fluence of 2.126 J/cm2, there were some nanostructures covered on the melt-induced curved microstructured surface. However, surface molten material submerged in the most of cracks at the spot overlap number of 744, where the old cracks disappeared. The results indicated that there was too much molten material and melting time at the peak laser fluence of 2.126 J/cm2, which was not suitable for obtainment of perfect micro-nano structures. On this basis, peak laser fluence was reduced down to 1.595 J/cm2 and the sharp sub-5 μm microstructures with nanostructures covered was obtained at spot overlap number of 3720.

  15. Picosecond ultrasonic study of surface acoustic waves on titanium nitride nanostructures

    SciTech Connect

    Bjornsson, M. M.; Connolly, A. B.; Mahat, S.; Rachmilowitz, B. E.; Daly, B. C.; Antonelli, G. A.; Myers, A.; Singh, K. J.; Yoo, H. J.; King, S. W.

    2015-03-07

    We have measured surface acoustic waves on nanostructured TiN wires overlaid on multiple thin films on a silicon substrate using the ultrafast pump-probe technique known as picosecond ultrasonics. We find a prominent oscillation in the range of 11–54 GHz for samples with varying pitch ranging from 420 nm down to 168 nm. We find that the observed oscillation increases monotonically in frequency with decrease in pitch, but that the increase is not linear. By comparing our data to two-dimensional mechanical simulations of the nanostructures, we find that the type of surface oscillation to which we are sensitive changes depending on the pitch of the sample. Surface waves on substrates that are loaded by thin films can take multiple forms, including Rayleigh-like waves, Sezawa waves, and radiative (leaky) surface waves. We describe evidence for detection of modes that display characteristics of these three surface wave types.

  16. Picosecond ultrasonic study of surface acoustic waves on titanium nitride nanostructures

    NASA Astrophysics Data System (ADS)

    Bjornsson, M. M.; Connolly, A. B.; Mahat, S.; Rachmilowitz, B. E.; Daly, B. C.; Antonelli, G. A.; Myers, A.; Singh, K. J.; Yoo, H. J.; King, S. W.

    2015-03-01

    We have measured surface acoustic waves on nanostructured TiN wires overlaid on multiple thin films on a silicon substrate using the ultrafast pump-probe technique known as picosecond ultrasonics. We find a prominent oscillation in the range of 11-54 GHz for samples with varying pitch ranging from 420 nm down to 168 nm. We find that the observed oscillation increases monotonically in frequency with decrease in pitch, but that the increase is not linear. By comparing our data to two-dimensional mechanical simulations of the nanostructures, we find that the type of surface oscillation to which we are sensitive changes depending on the pitch of the sample. Surface waves on substrates that are loaded by thin films can take multiple forms, including Rayleigh-like waves, Sezawa waves, and radiative (leaky) surface waves. We describe evidence for detection of modes that display characteristics of these three surface wave types.

  17. Electron transport in the nanostructured titanium dioxide electrodes in the application of solar cells

    NASA Astrophysics Data System (ADS)

    Cao, Fei

    The high efficiency of dye sensitized nanostructured TiO 2 photoelectrochemical solar cells underlines the high charge transfer efficiency at the semiconductor/dye interface and the ability of the nanometer sized TiO2 particle network in intimate contact with the electrolyte to transport the injected electrons without significant losses. The operating mechanisms of these photoelectrochemical systems are reviewed. The focus of this dissertation is the photoelectrical properties of nanostructured TiO 2 films and the associated charge transport process. Transient techniques, both in the time domain and frequency domain were used to probe the electron transport in the TiO2 electrodes. The conductivity of nanostructured TiO2 thin films increases several orders of magnitude under illumination yet the conductivity is very low in the dark, illustrating the fact that the conductivity is strongly dependent on the trapped charges in these films. Due to the lack of a strong electrical field, charge transport only becomes efficient after the build up of a concentration gradient to drive the electron transport process, resulting in slow photocurrent and photovoltage transients in the photoelectrochemical cells. The open circuit photovoltages follow the conventional diode equation. This can be understood in terms of the Fermi level at the TiO2/tin oxide contact. The injection of electrons leads to the increase of the Fermi level at the contact. The time constants obtained follow a simple power law relationship with the light intensity reflecting the kinetics of electron transport in the nanostructured electrodes. The essential features of the nonsteady state response can be described by a diffusion model where the electron diffusion coefficient is dependent on light intensity. The lack of electron migration can be rationalized by the fact that any electrical field in the porous electrodes may be neutralized by the mobile ions in the electrolyte.

  18. Investigation into Self-Organizational Tendencies of Cobalt- and Titanium-Silicide Nanostructures on Si Surfaces

    DTIC Science & Technology

    2008-09-22

    properties , directly affects interaction with the deposited metal adatoms, and in conjunction with the metal deposition method, determines the silicide ...formation kinetics and the properties of the silicide /silicon interface. Morphological and statistical characteristics, and the resulting collective...Report 3. DATES COVERED (From – To) 1 April 2007 - 01-Apr-08 4. TITLE AND SUBTITLE Self-Organization of Cobalt Silicide Nanostructures into 2D

  19. Anti-infection activity of nanostructured titanium percutaneous implants with a postoperative infection model

    NASA Astrophysics Data System (ADS)

    Tan, Jing; Li, Yiting; Liu, Zhiyuan; Qu, Shuxin; Lu, Xiong; Wang, Jianxin; Duan, Ke; Weng, Jie; Feng, Bo

    2015-07-01

    The titanium percutaneous implants were widely used in clinic; however, they have an increased risk of infection since they breach the skin barrier. Lack of complete skin integration with the implants can cause infection and implant removal. In this work, three titania nanotubes (TNT) with different diameters, 50 nm (TNT-50), 100 nm (TNT-100) and 150 nm (TNT-150) arrays were prepared on titanium surfaces by anodization, pure titanium (pTi) was used as control. Samples were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), and contact angle analysis. The antibacterial efficiency of TNT was evaluated in vitro against Staphylococcus aureus under the visible light. The results indicated that TNT-100 had the highest antibacterial efficiency under the visible light. Subsequently, TNT implants and pTi implants were placed subcutaneously to the dorsum of New Zealand White rabbits, 108 CFU S. aureus was inoculated into the implant sites 4 h after surgery. The TNF-alpha and IL-1alpha were determined using enzyme linked immunoassay (ELISA). TNT implants revealed less inflammatory factor release than pTi implants with or without injected S. aureus liquid. According to the histological results, the TNT implants displayed excellent tissue integration. Whereas, pTi implants were surrounded with fibrotic capsule, and the skin tissue was almost separated from the implant surface. Therefore, the TNT significantly inhibited the infection risk and enhanced tissue integration of the percutaneous implants compared to pTi. The immersion test in the culture medium suggested that one of causes be probably more proteins adsorbed on TNT than on pTi.

  20. Structure of Ti-6Al-4V nanostructured titanium alloy joint obtained by resistance spot welding

    SciTech Connect

    Klimenov, V. A.; Kurgan, K. A.; Chumaevskii, A. V.; Gnyusov, S. F.

    2016-01-15

    The structure of weld joints of the titanium alloy Ti-6Al-4V in the initial ultrafine-grained state, obtained by resistance spot welding, is studied using the optical and scanning electron microscopy method and the X-ray structure analysis. The carried out studies show the relationship of the metal structure in the weld zone with main joint zones. The structure in the core zone and the heat affected zone is represented by finely dispersed grains of needle-shaped martensite, differently oriented in these zones. The change in the microhardness in the longitudinal section of the weld joint clearly correlates with structural changes during welding.

  1. Nanostructured anatase-titanium dioxide based platform for application to microfluidics cholesterol biosensor

    NASA Astrophysics Data System (ADS)

    Azahar Ali, Md.; Srivastava, Saurabh; Solanki, Pratima R.; Varun Agrawal, Ved; John, Renu; Malhotra, Bansi D.

    2012-08-01

    We report results of studies relating to the fabrication of a microfluidics cholesterol sensor based on nanocrystalline anatase-titanium dioxide (ant-TiO2) film deposited onto indium tin oxide (ITO) glass. The results of response studies (optimized under the flow rate of 30 μl/min) conducted on cholesterol oxidase (ChOx) immobilized onto crystalline ant-TiO2 nanoparticles (˜27 nm)/ITO microfluidics electrode reveal linearity as 1.3 to 10.3 mM and improved sensitivity of 94.65 μA/mM/cm2. The observed low value of Km (0.14 mM) indicates high affinity of ChOx to cholesterol. No significant changes in current response of this microfluidics sensor are measured in the presence of different interferents.

  2. Effect of nanostructured graphene oxide on electrochemical activity of its composite with polyaniline titanium dioxide

    NASA Astrophysics Data System (ADS)

    Binh Phan, Thi; Thanh Luong, Thi; Mai, Thi Xuan; Thanh Thuy Mai, Thi; Tot Pham, Thi

    2016-03-01

    Graphene oxide (GO) significantly affects the electrochemical activity of its composite with polyanline titanium dioxide (TiO2). In this work various composites with different GO contents have been successfully synthesized by chemical method to compare not only their material properties but also electrochemical characteristics with each other. The results of an electrochemical impedance study showed that their electrochemical property has been improved due to the presence of GO in a composite matrix. The galvanodynamic polarization explained that among them the composite with GO/Ani ratio in the range of 1-14 exhibits a better performance compared to the other due to yielding a higher current desity (280 μA cm-2). The TEM and SEM images which presented the fibres of a composite bundle with the presence of PANi and TiO2 were examined by IR-spectra and x-ray diffraction, respectively.

  3. Hierarchical micro/nanostructured titanium with balanced actions to bacterial and mammalian cells for dental implants

    PubMed Central

    Zhu, Yu; Cao, Huiliang; Qiao, Shichong; Wang, Manle; Gu, Yingxin; Luo, Huiwen; Meng, Fanhao; Liu, Xuanyong; Lai, Hongchang

    2015-01-01

    A versatile strategy to endow dental implants with long-term antibacterial ability without compromising the cytocompatibility is highly desirable to combat implant-related infection. Silver nanoparticles (Ag NPs) have been utilized as a highly effective and broad-spectrum antibacterial agent for surface modification of biomedical devices. However, the high mobility and subsequent hazardous effects of the particles on mammalian cells may limit its practical applications. Thus, Ag NPs were immobilized on the surface of sand-blasted, large grit, and acid-etched (SLA) titanium by manipulating the atomic-scale heating effect of silver plasma immersion ion implantation. The silver plasma immersion ion implantation-treated SLA surface gave rise to both good antibacterial activity and excellent compatibility with mammalian cells. The antibacterial activity rendered by the immobilized Ag NPs was assessed using Fusobacterium nucleatum and Staphylococcus aureus, commonly suspected pathogens for peri-implant disease. The immobilized Ag NPs offered a good defense against multiple cycles of bacteria attack in both F. nucleatum and S. aureus, and the mechanism was independent of silver release. F. nucleatum showed a higher susceptibility to Ag NPs than S. aureus, which might be explained by the presence of different wall structures. Moreover, the immobilized Ag NPs had no apparent toxic influence on the viability, proliferation, and differentiation of rat bone marrow mesenchymal stem cells. These results demonstrated that good bactericidal activity could be obtained with very small quantities of immobilized Ag NPs, which were not detrimental to the mammalian cells involved in the osseointegration process, and promising for titanium-based dental implants with commercial SLA surfaces. PMID:26604743

  4. Study on the Effect of Various Sol-Gel Concentration to the Electrical, Structural and Optical Properties of the Nanostructured Titanium Dioxide Thin Films

    NASA Astrophysics Data System (ADS)

    Ahmad, M. K.; Rusop, M.

    2009-06-01

    Nanostructured Titanium Dioxide (TiO2) thin film with various sol-gel concentration has been successfully prepared using sol-gel spin coating method. The sol-gel concentration of nanostructured TiO2 thin films are varied at 0.1 M, 0.2 M, 0.3 M and 0.4 M, respectively. The effects of different sol-gel concentration of nanostructured TiO2 thin film structural, electrical and optical properties have been studied. The effects of these properties were characterized using X-Ray Diffractometer (XRD), 2-point probe I-V measurement and UV-Vis-NIR Spectrophotometer. For electrical properties, 0.2 M of sol-gel concentration gives the lowest sheet resistance among other concentrated sol-gels. As for structural properties, 0.1 M of concentration gives very weak peak, and continues stronger as in comes to 0.2 M until 0.4 M. It is due to amount of solute (i.e Titanium Isopropoxide) increases in the solution and therefore the intensity of (101) planes become higher. The optical transmission in the visible region (450-1000 nm) for 0.1 M and 0.2 M are the highest (>80%), indicating that the films are transparent in the visible region. The transmission decreases sharply near the ultraviolet region due to the band gap absorption.

  5. Nanostructured titanium nitride as a novel cathode for high performance lithium/dissolved polysulfide batteries

    NASA Astrophysics Data System (ADS)

    Mosavati, Negar; Chitturi, Venkateswara Rao; Salley, Steven O.; Ng, K. Y. Simon

    2016-07-01

    Lithium-sulfur (Lisbnd S) batteries could potentially revolutionize the rechargeable battery market due to their high energy density and low cost. However, low active material utilization, electrode volumetric expansion and a high rate of capacity fade due to the dissolution of lithium polysulfide intermediates in the liquid electrolyte are the main challenges facing further Lisbnd S battery development. Here, we enhanced Lisbnd S batteries active material utilization and decreased the volumetric expansion by using the lithium/dissolved polysulfide configuration. Moreover, a novel class of cathode materials, Titanium Nitride (TiN), was developed for polysulfide conversion reactions. The surface chemical environment of the TiN has been investigated by X-ray photoelectron spectroscopy (XPS) analysis. The existence of Ssbnd Tisbnd N bonding at the cathode electrode surface was observed, which indicates the strong interactions between TiN and polysulfides. Therefore, the TiN electrode retains the sulfur species on the cathode surface, minimizing the active material and surface area loss and consequently, improves the capacity retention. The resultant cells demonstrated a high initial capacity of 1524 mAh g-1 and a good capacity retention for 100 cycles at a C/10 current rate.

  6. Nanostructured titanium/diamond-like carbon multilayer films: deposition, characterization, and applications.

    PubMed

    Dwivedi, Neeraj; Kumar, Sushil; Malik, Hitendra K

    2011-11-01

    Titanium/diamond-like carbon multilayer (TDML) films were deposited using a hybrid system combining radio frequency (RF)-sputtering and RF-plasma enhanced chemical vapor deposition (PECVD) techniques under a varied number of Ti/diamond-like carbon (DLC) bilayers from 1 to 4, at high base pressure of 1 × 10(-3) Torr. The multilayer approach was used to create unique structures such as nanospheres and nanorods in TDML films, which is confirmed by scanning electron microscopy (SEM) analysis and explained by a hypothetical model. Surface composition was evaluated by X-ray photoelectron spectroscopy (XPS), whereas energy dispersive X-ray analysis (EDAX) and time-of-flight secondary ion mass spectrometer (ToF-SIMS) measurements were performed to investigate the bulk composition. X-ray diffraction (XRD) was used to evaluate the phase and crystallinity of the deposited TDML films. Residual stress in these films was found to be significantly low. These TDML films were found to have excellent nanomechanical properties with maximum hardness of 41.2 GPa. In addition, various nanomechanical parameters were calculated and correlated with each other. Owing to metallic interfacial layer of Ti in multilayer films, the optical properties, electrical properties, and photoluminescence were improved significantly. Due to versatile nanomechanical properties and biocompatibility of DLC and DLC based films, these TDML films may also find applications in biomedical science.

  7. MAO-derived hydroxyapatite/TiO2 nanostructured multi-layer coatings on titanium substrate

    NASA Astrophysics Data System (ADS)

    Abbasi, S.; Golestani-Fard, F.; Rezaie, H. R.; Mirhosseini, S. M. M.

    2012-11-01

    In this study, titanium substrates which previously oxidized through Micro arc oxidation method, was coated by Hydroxyapatite (HAp) coating once more by means of the same method. Morphology, topography and chemical properties as well as phase composition and thickness of layers were studied to reveal the effect of the electrolyte concentration on coating features. According to results, the obtained coatings are consisted of HAp and titania as the major phases along with minor amounts of calcium titanate and α-tri calcium phosphate. Ca and P are present on surface of obtained layers as well as predictable Ti and O based on the XPS results. Thickness profile of coatings figured out that by increasing the electrolyte concentration, especially by addition of more Calcium Acetate (CA) to electrolyte, the thickness of HAp layer would rise, consequently. However, the influence of coating time on thickness of obtained coatings would be more considerable than electrolyte concentration. High specific area coatings with nest morphology were obtained in Electrolyte containing 5 g/L β-Glycero Phosphate (β-GP) and 5 g/L CA. Increasing coating duration time in this kind of coatings would cause deduction of the nesting in their structure.

  8. Tunable top-down fabrication and functional surface coating of single-crystal titanium dioxide nanostructures and nanoparticles

    NASA Astrophysics Data System (ADS)

    Ha, Seungkyu; Janissen, Richard; Ussembayev, Yera Ye.; van Oene, Maarten M.; Solano, Belen; Dekker, Nynke H.

    2016-05-01

    Titanium dioxide (TiO2) is a key component of diverse optical and electronic applications that exploit its exceptional material properties. In particular, the use of TiO2 in its single-crystalline phase can offer substantial advantages over its amorphous and polycrystalline phases for existing and yet-to-be-developed applications. However, the implementation of single-crystal TiO2 has been hampered by challenges in its fabrication and subsequent surface functionalization. Here, we introduce a novel top-down approach that allows for batch fabrication of uniform high-aspect-ratio single-crystal TiO2 nanostructures with targeted sidewall profiles. We complement our fabrication approach with a functionalization strategy that achieves dense, uniform, and area-selective coating with a variety of biomolecules. This allows us to fabricate single-crystal rutile TiO2 nanocylinders tethered with individual DNA molecules for use as force- and torque-transducers in an optical torque wrench. These developments provide the means for increased exploitation of the superior material properties of single-crystal TiO2 at the nanoscale.Titanium dioxide (TiO2) is a key component of diverse optical and electronic applications that exploit its exceptional material properties. In particular, the use of TiO2 in its single-crystalline phase can offer substantial advantages over its amorphous and polycrystalline phases for existing and yet-to-be-developed applications. However, the implementation of single-crystal TiO2 has been hampered by challenges in its fabrication and subsequent surface functionalization. Here, we introduce a novel top-down approach that allows for batch fabrication of uniform high-aspect-ratio single-crystal TiO2 nanostructures with targeted sidewall profiles. We complement our fabrication approach with a functionalization strategy that achieves dense, uniform, and area-selective coating with a variety of biomolecules. This allows us to fabricate single-crystal rutile

  9. Superposition of nanostructures on microrough titanium-aluminum-vanadium alloy surfaces results in an altered integrin expression profile in osteoblasts.

    PubMed

    Gittens, Rolando A; Olivares-Navarrete, Rene; Hyzy, Sharon L; Sandhage, Kenneth H; Schwartz, Zvi; Boyan, Barbara D

    2014-08-01

    Recent studies of new surface modifications that superimpose well-defined nanostructures on microrough implants, thereby mimicking the hierarchical complexity of native bone, report synergistically enhanced osteoblast maturation and local factor production at the protein level compared to growth on surfaces that are smooth, nanorough, or microrough. Whether the complex micro/nanorough surfaces enhance the osteogenic response by triggering similar patterns of integrin receptors and their associated signaling pathways as with well-established microrough surfaces, is not well understood. Human osteoblasts (hOBs) were cultured until confluent for gene expression studies on tissue culture polystyrene (TCPS) or on titanium alloy (Ti6Al4V) disks with different surface topographies: smooth, nanorough, microrough, and micro/nanorough surfaces. mRNA expression of osteogenesis-related markers such as osteocalcin (BGLAP) and bone sialoprotein (BSP), bone morphogenetic protein 2 (BMP2), BMP4, noggin (NOG) and gremlin 1 (GREM1) were all higher on microrough and micro/nanorough surfaces, with few differences between them, compared to smooth and nanorough groups. Interestingly, expression of integrins α1 and α2, which interact primarily with collagens and laminin and have been commonly associated with osteoblast differentiation on microrough Ti and Ti6Al4V, were expressed at lower levels on micro/nanorough surfaces compared to microrough ones. Conversely, the αv subunit, which binds ligands such as vitronectin, osteopontin, and bone sialoprotein among others, had higher expression on micro/nanorough surfaces concomitantly with regulation of the β3 mRNA levels on nanomodified surfaces. These results suggest that the maturation of osteoblasts on micro/nanorough surfaces may be occurring through different integrin engagement than those established for microrough-only surfaces.

  10. Influence of Glacial Acetic Acid and Nitric Acid as a Chelating Agent in Sol-gel Process to the Nanostructured Titanium Dioxide Thin Films

    NASA Astrophysics Data System (ADS)

    Ahmad, M. K.; Rusop, M.

    2009-06-01

    The comparison between different chelating agents in sol-gel process for deposition of nanostructured Titanium Dioxide (TiO2) thin film has been studied. Glacial Acetic Acid (GA) and Nitric Acid (NA) were used in 0.2 M of concentration. The effects to the structural, electrical and optical properties have been studied. The effects of these properties were characterized using X-Ray Diffractometer (XRD), 2-point probe I-V measurement and UV-Vis-NIR Spectrophotometer. For electrical properties, it showed that nanostructured TiO2 thin film that using GA (TF-GA) as chelating agent gives better low sheet resistance compare to nanostructured TiO2 thin film using NA (TF-NA). From XRD results, it indicates that no significantly different between both TiO2 thin film. Both of thin films have crystalline anatase phase at 2θ degree 25.8° which corresponded to (101) orientation. For optical properties, sol-gel using GA has slightly higher in transmittance spectra properties but both of films fully absorbed UV light at 300 nm of wavelength. As for optical band gap, both sol-gels using GA and NA has similar optical band gap which is 3.27 eV.

  11. In Situ Generation of Electron Donor to Assist Signal Amplification on Porphyrin-Sensitized Titanium Dioxide Nanostructures for Ultrasensitive Photoelectrochemical Immunoassay.

    PubMed

    Shu, Jian; Qiu, Zhenli; Zhuang, Junyang; Xu, Mingdi; Tang, Dianping

    2015-10-28

    An ultrasensitive photoelectrochemical (PEC) immunoassay protocol for quantitative detection of low-abundant proteins at a low potential was designed by utilizing porphyrin-sensitized titanium dioxide (TiO2) nanostructures. Experimental results demonstrated that the water-soluble 5,10,15,20-tetra(4-sulfophenyl)-21H,23H-porphyrin (TSPP) could be bound onto titanium dioxide via the sulfonic group. TSPP-sensitized TiO2 nanostructures exhibited better photoelectrochemical responses and stability in comparison with TiO2 nanoparticles alone under continuous illumination. Using carcinoembryonic antigen (CEA) as a model analyte, a typical PEC immunosensor by using TSPP-TiO2 as the affinity support of anti-CEA capture antibody (Ab1) to facilitate the improvement of photocurrent response was developed. Bioconjugates of secondary antibody and glucose oxidase with gold nanoparticles (Ab2/GOx-AuNPs) was introduced by an antigen-antibody immunoreaction. AuNP acted as a powerful scaffold to bind with bioactive molecules, while GOx catalyzed glucose to in situ generate hydrogen peroxide (H2O2). The generated H2O2 as a sacrificial electron donor could be oxidized by the photogenerated holes to assist the signal amplification at a low potential under light excitation, thus eliminating interference from other species coexisting in the samples. Under optimal conditions, the PEC immunosensor showed a good linear relationship ranging from 0.02 to 40 ng mL(-1) with a low detection limit of 6 pg mL(-1) CEA. The precision, reproducibility, and specificity were acceptable. In addition, the method accuracy was also evaluated for quantitatively monitoring human serum samples, giving results matching with the referenced CEA ELISA kit.

  12. Surface analysis and biocorrosion properties of nanostructured surface sol-gel coatings on Ti6Al4V titanium alloy implants.

    PubMed

    Advincula, Maria C; Petersen, Don; Rahemtulla, Firoz; Advincula, Rigoberto; Lemons, Jack E

    2007-01-01

    Surfaces of biocompatible alloys used as implants play a significant role in their osseointegration. Surface sol-gel processing (SSP), a variant of the bulk sol-gel technique, is a relatively new process to prepare bioreactive nanostructured titanium oxide for thin film coatings. The surface topography, roughness, and composition of sol-gel processed Ti6Al4V titanium alloy coatings was investigated by atomic force microscopy (AFM) and X-ray electron spectroscopy (XPS). This was correlated with corrosion properties, adhesive strength, and bioreactivity in simulated body fluids (SBF). Electroimpedance spectroscopy (EIS) and polarization studies indicated similar advantageous corrosion properties between sol-gel coated and uncoated Ti6Al4V, which was attributed to the stable TiO2 composition, topography, and adhesive strength of the sol-gel coating. In addition, inductive coupled plasma (ICP) and scanning electron microscopy with energy dispersive spectrometry (SEM-EDS) analysis of substrates immersed in SBF revealed higher deposition of calcium and phosphate and low release rates of alloying elements from the sol-gel modified alloys. The equivalent corrosion behavior and the definite increase in nucleation of calcium apatite indicate the potential of the sol-gel coating for enhanced bioimplant applications.

  13. Semi-transparent ordered TiO2 nanostructures prepared by anodization of titanium thin films deposited onto the FTO substrate

    NASA Astrophysics Data System (ADS)

    Szkoda, Mariusz; Lisowska-Oleksiak, Anna; Grochowska, Katarzyna; Skowroński, Łukasz; Karczewski, Jakub; Siuzdak, Katarzyna

    2016-09-01

    In a significant amount of cases, the highly ordered TiO2 nanotube arrays grow through anodic oxidation of a titanium metal plate immersed in electrolyte containing fluoride ions. However, for some practical applications, e.g. solar cells or electrochromic windows, the semi-transparent TiO2 formed directly on the transparent, conductive substrate is very much desired. This work shows that high-quality Ti coating could be formed at room temperature using an industrial magnetron sputtering system within 50 min. Under optimized conditions, the anodization process was performed on 2 μm titanium films deposited onto the FTO (fluorine-tin-oxide) support. Depending on the electrolyte type, highly ordered tubular or porous titania layers were obtained. The fabricated samples, after their thermal annealing, were investigated using scanning electron microscopy, Raman spectroscopy and UV-vis spectroscopy in order to investigate their morphology, crystallinity and absorbance ability. The photocurrent response curves indicate that materials are resistant to the photocorrosion process and their activity is strongly connected to optical properties. The most transparent TiO2 films were fabricated when Ti was anodized in water electrolyte, whereas the highest photocurrent densities (12 μA cm-2) were registered for titania received after Ti anodization in ethylene glycol solution. The obtained results are of significant importance in the production of thin, semi-transparent titania nanostructures on a commercial scale.

  14. Hybrid nanostructured microporous carbon-mesoporous carbon doped titanium dioxide/sulfur composite positive electrode materials for rechargeable lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Zegeye, Tilahun Awoke; Kuo, Chung-Feng Jeffrey; Wotango, Aselefech Sorsa; Pan, Chun-Jern; Chen, Hung-Ming; Haregewoin, Atetegeb Meazah; Cheng, Ju-Hsiang; Su, Wei-Nien; Hwang, Bing-Joe

    2016-08-01

    Herein, we design hybrid nanostructured microporous carbon-mesoporous carbon doped titanium dioxide/sulfur composite (MC-Meso C-doped TiO2/S) as a positive electrode material for lithium-sulfur batteries. The hybrid MC-Meso C-doped TiO2 host material is produced by a low-cost, hydrothermal and annealing process. The resulting conductive material shows dual microporous and mesoporous behavior which enhances the effective trapping of sulfur and polysulfides. The hybrid MC-Meso C-doped TiO2/S composite material possesses rutile TiO2 nanotube structure with successful carbon doping while sulfur is uniformly distributed in the hybrid MC-Meso C-doped TiO2 composite materials after the melt-infusion process. The electrochemical measurement of the hybrid material also shows improved cycle stability and rate performance with high sulfur loading (61.04%). The material delivers an initial discharge capacity of 802 mAh g-1 and maintains it at 578 mAh g-1 with a columbic efficiency greater than 97.1% after 140 cycles at 0.1 C. This improvement is thought to be attributed to the unique hybrid nanostructure of the MC-Meso C-doped TiO2 host and the good dispersion of sulfur in the narrow pores of the MC spheres and the mesoporous C-doped TiO2 support.

  15. Q-Switching in a Neodymium Laser

    ERIC Educational Resources Information Center

    Holgado, Warein; Sola, Inigo J.; Jarque, Enrique Conejero; Jarabo, Sebastian; Roso, Luis

    2012-01-01

    We present a laboratory experiment for advanced undergraduate or graduate laser-related classes to study the performance of a neodymium laser. In the experiment, the student has to build the neodymium laser using an open cavity. After that, the cavity losses are modulated with an optical chopper located inside, so the Q-switching regime is…

  16. Nanostructured Graphene-Titanium Dioxide Composites Synthesized by a Single-Step Aerosol Process for Photoreduction of Carbon Dioxide

    PubMed Central

    Wang, Wei-Ning; Jiang, Yi; Fortner, John D.; Biswas, Pratim

    2014-01-01

    Abstract Photocatalytic reduction of carbon dioxide (CO2) to hydrocarbons by using nanostructured materials activated by solar energy is a promising approach to recycling CO2 as a fuel feedstock. CO2 photoreduction, however, suffers from low efficiency mainly due to the inherent drawback of fast electron-hole recombination in photocatalysts. This work reports the synthesis of nanostructured composites of titania (TiO2) nanoparticles (NPs) encapsulated by reduced graphene oxide (rGO) nanosheets via an aerosol approach. The role of synthesis temperature and TiO2/GO ratio in CO2 photoreduction was investigated. As-prepared nanocomposites demonstrated enhanced CO2 conversion performance as compared with that of pristine TiO2 NPs due to the strong electron trapping capability of the rGO nanosheets. PMID:25053879

  17. Facile one-step synthesis of highly branched ZnO nanostructures on titanium foil for flexible dye-sensitized solar cells.

    PubMed

    Zhang, Juntao; He, Meng; Fu, Nianqing; Li, Jianye; Yin, Xiong

    2014-04-21

    Highly branched ZnO (HBZ) nanostructures were prepared on titanium (Ti) foil using a facile, one-step vapor confined chemical vapor deposition technique. The as-prepared ZnO layer showed a good connection with the Ti foil even after 50 bending cycles, and the resultant HBZ/Ti electrode possessed high bendability. The HBZ/Ti electrode was composed of four different layers, including a highly branched ZnO layer, a ZnO compact layer, a Ti-Zn alloy layer and Ti foil. The good adhesion of the as-prepared ZnO layer to Ti foil was ascribed to the formation of a Ti-Zn alloy layer and a ZnO compact layer during the growth process. A flexible dye-sensitized solar cell was assembled using the D149-sensitized HBZ/Ti as a photoanode, and a power conversion efficiency (PCE) of 3.3% was achieved with an open-circuit photovoltage of 0.664 V, a short-circuit current density of 7.53 mA cm(-2), and a fill factor of 0.66 measured under rear-side illumination (AM 1.5, 100 mW cm(-2)). The power conversion efficiency of the device remained at 92% of the initial value even after 50 bending cycles. These results indicate that the vapor confined chemical vapor deposition method which does not necessarily use any catalyst or seed is a facile, one-step approach to obtain highly branched ZnO nanostructures with high bendability on Ti foil. The tight bonding between the highly branched ZnO layer and Ti substrate by a Ti-Zn alloy layer and a ZnO compact layer makes the vapor confined CVD method very attractive for the preparation of high-performance flexible photoanodes.

  18. Facile one-step synthesis of highly branched ZnO nanostructures on titanium foil for flexible dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Zhang, Juntao; He, Meng; Fu, Nianqing; Li, Jianye; Yin, Xiong

    2014-03-01

    Highly branched ZnO (HBZ) nanostructures were prepared on titanium (Ti) foil using a facile, one-step vapor confined chemical vapor deposition technique. The as-prepared ZnO layer showed a good connection with the Ti foil even after 50 bending cycles, and the resultant HBZ/Ti electrode possessed high bendability. The HBZ/Ti electrode was composed of four different layers, including a highly branched ZnO layer, a ZnO compact layer, a Ti-Zn alloy layer and Ti foil. The good adhesion of the as-prepared ZnO layer to Ti foil was ascribed to the formation of a Ti-Zn alloy layer and a ZnO compact layer during the growth process. A flexible dye-sensitized solar cell was assembled using the D149-sensitized HBZ/Ti as a photoanode, and a power conversion efficiency (PCE) of 3.3% was achieved with an open-circuit photovoltage of 0.664 V, a short-circuit current density of 7.53 mA cm-2, and a fill factor of 0.66 measured under rear-side illumination (AM 1.5, 100 mW cm-2). The power conversion efficiency of the device remained at 92% of the initial value even after 50 bending cycles. These results indicate that the vapor confined chemical vapor deposition method which does not necessarily use any catalyst or seed is a facile, one-step approach to obtain highly branched ZnO nanostructures with high bendability on Ti foil. The tight bonding between the highly branched ZnO layer and Ti substrate by a Ti-Zn alloy layer and a ZnO compact layer makes the vapor confined CVD method very attractive for the preparation of high-performance flexible photoanodes.

  19. Neodymium neutron cross section measurements.

    PubMed

    Barry, D P; Trbovich, M J; Danon, Y; Block, R C; Slovacek, R E; Leinweber, G; Burke, J A; Drindak, N J

    2005-01-01

    Neutron capture and transmission measurements were performed by the time-of-flight technique at the Rensselaer Polytechnic Institute LINAC using metallic neodymium samples. The capture measurements were made at the 25-m-long flight station with a 16-segment NaI(Tl) multiplicity detector, and the transmission measurements were performed at 15 and 25 m flight stations with a 6Li glass scintillation detector. After the data were collected and reduced, resonance parameters were determined by simultaneously fitting the transmission and capture data with the multilevel R-matrix Bayesian code SAMMY. The resonance parameters for all naturally occurring neodymium isotopes lie within the energy range of 1.0-500 eV. The resulting resonance parameters were used to calculate the capture resonance integral with this energy region and were compared to calculations obtained when using the resonance parameters from ENDF-B/VI. The RPI parameters gave a resonance integral value of 32 +/- 0.5 b that is approximately 7% lower than that obtained with the ENDF-B/VI parameters. The current measurements significantly reduce the statistical uncertainties on the resonance parameters when compared with previously published parameters.

  20. Osseointegration properties of titanium dental implants modified with a nanostructured coating based on ordered porous silica and bioactive glass nanoparticles

    NASA Astrophysics Data System (ADS)

    Covarrubias, Cristian; Mattmann, Matías; Von Marttens, Alfredo; Caviedes, Pablo; Arriagada, Cristián; Valenzuela, Francisco; Rodríguez, Juan Pablo; Corral, Camila

    2016-02-01

    The fabrication of a nanoporous silica coating loaded with bioactive glass nanoparticles (nBG/NSC) on titanium dental implant surface and its in vitro and in vivo evaluation is presented. The coating was produced by a combined sol-gel and evaporation induced self-assembly process. In vitro bioactivity was assessed in simulated body fluid (SBF) and investigating the osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs). A rat tibial model was employed to analyze the bone response to nBG/NSC-modified titanium implant surface in vivo. The nBG/NSC coating was confirmed at nano level to be constituted by a highly ordered nanoporous silica structure. The coating nanotopography in conjunction with the bioactivity of the BG particles accelerate the in vitro apatite formation and promote the osteogenic differentiation of hBMSCs in absence of osteogenic supplements. These properties accelerate the formation of bone tissue in the periphery of the implant after 3 weeks of implantation. Backscattered scanning electron microscopy images revealed the presence of gaps and soft tissue in the unmodified implant after 6 weeks, whereas the nBG/NSC-modified implant showed mature bone in intimate contact with the implant surface. The nBG/NSC coating appears promising for accelerating the osseointegration of dental implants.

  1. Equilibrium state of anatase to rutile transformation for nano-structured Titanium Dioxide powder using polymer template method.

    NASA Astrophysics Data System (ADS)

    Dam, Tapabrata; Jena, Sidhartha S.; Pradhan, Dillip K.

    2016-02-01

    In this work we report the novel synthesis procedure of phase-pure nano-structured titania in anatase phase using polyacrylamide gel based polymer template method. The evolution of rutile phased titania with increasing temperature has also been investigated. The synthesized nano-materials are characterized using X-ray diffraction, Brunauer - Emmett - Teller surface analysis technique and Scanning electron microscopy. We have used dual phase Rietveld refinement method to analyse the X-Ray diffraction data to get clear picture of crystallographic information of the prepared samples.

  2. Nanostructures having crystalline and amorphous phases

    DOEpatents

    Mao, Samuel S; Chen, Xiaobo

    2015-04-28

    The present invention includes a nanostructure, a method of making thereof, and a method of photocatalysis. In one embodiment, the nanostructure includes a crystalline phase and an amorphous phase in contact with the crystalline phase. Each of the crystalline and amorphous phases has at least one dimension on a nanometer scale. In another embodiment, the nanostructure includes a nanoparticle comprising a crystalline phase and an amorphous phase. The amorphous phase is in a selected amount. In another embodiment, the nanostructure includes crystalline titanium dioxide and amorphous titanium dioxide in contact with the crystalline titanium dioxide. Each of the crystalline and amorphous titanium dioxide has at least one dimension on a nanometer scale.

  3. High-value chemicals obtained from selective photo-oxidation of glucose in the presence of nanostructured titanium photocatalysts.

    PubMed

    Colmenares, Juan C; Magdziarz, Agnieszka; Bielejewska, Anna

    2011-12-01

    Glucose was oxidized in the presence of powdered TiO(2) photocatalysts synthesized by an ultrasound-promoted sol-gel method. The catalysts were more selective towards glucaric acid, gluconic acid and arabitol (total selectivity approx. 70%) than the most popular photocatalyst, Degussa P-25. The photocatalytic systems worked at mild reaction conditions: 30°C, atmospheric pressure and very short reaction time (e.g. 5 min). Such relatively good selectivity towards high-valued molecules are attributed to the physico-chemical properties (e.g. high specific surface area, nanostructured anatase phase, and visible light absorption) of novel TiO(2) materials and the reaction conditions. The TiO(2) photocatalysts have potential for water purification and energy production and for use in the pharmaceutical, food, perfume and fuel industries.

  4. ZnO nanoparticle incorporated nanostructured metallic titanium for increased mesenchymal stem cell response and antibacterial activity

    NASA Astrophysics Data System (ADS)

    Elizabeth, Elmy; Baranwal, Gaurav; Krishnan, Amit G.; Menon, Deepthy; Nair, Manitha

    2014-03-01

    Recent trends in titanium implants are towards the development of nanoscale topographies that mimic the nanoscale properties of bone tissue. Although the nanosurface promotes the integration of osteoblast cells, infection related problems can also occur, leading to implant failure. Therefore it is imperative to reduce bacterial adhesion on an implant surface, either with or without the use of drugs/antibacterial agents. Herein, we have investigated two different aspects of Ti surfaces in inhibiting bacterial adhesion and concurrently promoting mammalian cell adhesion. These include (i) the type of nanoscale topography (Titania nanotube (TNT) and Titania nanoleaf (TNL)) and (ii) the presence of an antibacterial agent like zinc oxide nanoparticles (ZnOnp) on Ti nanosurfaces. To address this, periodically arranged TNT (80-120 nm) and non-periodically arranged TNL surfaces were generated by the anodization and hydrothermal techniques respectively, and incorporated with ZnOnp of different concentrations (375 μM, 750 μM, 1.125 mM and 1.5 mM). Interestingly, TNL surfaces decreased the adherence of staphylococcus aureus while increasing the adhesion and viability of human osteosarcoma MG63 cell line and human mesenchymal stem cells, even in the absence of ZnOnp. In contrast, TNT surfaces exhibited an increased bacterial and mammalian cell adhesion. The influence of ZnOnp on these surfaces in altering the bacterial and cell adhesion was found to be concentration dependent, with an optimal range of 375-750 μM. Above 750 μM, although bacterial adhesion was reduced, cellular viability was considerably affected. Thus our study helps us to infer that nanoscale topography by itself or its combination with an optimal concentration of antibacterial ZnOnp would provide a differential cell behavior and thereby a desirable biological response, facilitating the long term success of an implant.

  5. Electrolysis of neodymium oxide. Final report for the period August 19, 1991 through February 28, 1997

    SciTech Connect

    Keller, R.; Larimer, K.T.

    1997-05-01

    The objective of this research was to develop an electrolytic process for the continuous and economic production of neodymium alloys from neodymium oxide. The electrolysis of neodymium oxide continued to show promise for implementation as a low-cost process to produce high- quality neodymium or neodymium-iron alloy.

  6. Radio-Purification of Neodymium Chloride

    SciTech Connect

    Hans, S.; Yeh, M.; Cumming, J. B.; Hahn, R. L.

    2011-04-27

    Organometallic liquid scintillator becomes one of the man detection mediums for neutrino experiment. Liquid-liquid extraction is the method of choice for loading metallic ions of interest into the organic solvents at BNL. High purity of all starting materials is essential for the optimization of synthesis. A newly developed 'self-scavenging' technique was applied to purify undesired radioisotopes from the starting metal compound and found to effectively remove thorium and such containments from the neodymium chloride for SNO+.

  7. Hydrogen content in titanium and a titanium-zirconium alloy after acid etching.

    PubMed

    Frank, Matthias J; Walter, Martin S; Lyngstadaas, S Petter; Wintermantel, Erich; Haugen, Håvard J

    2013-04-01

    Dental implant alloys made from titanium and zirconium are known for their high mechanical strength, fracture toughness and corrosion resistance in comparison with commercially pure titanium. The aim of the study was to investigate possible differences in the surface chemistry and/or surface topography of titanium and titanium-zirconium surfaces after sand blasting and acid etching. The two surfaces were compared by X-ray photoelectron spectroscopy, secondary ion mass spectroscopy, scanning electron microscopy and profilometry. The 1.9 times greater surface hydrogen concentration of titanium zirconium compared to titanium was found to be the major difference between the two materials. Zirconium appeared to enhance hydride formation on titanium alloys when etched in acid. Surface topography revealed significant differences on the micro and nanoscale. Surface roughness was increased significantly (p<0.01) on the titanium-zirconium alloy. High-resolution images showed nanostructures only present on titanium zirconium.

  8. Neodymium-142 evidence for Hadean mafic crust.

    PubMed

    O'Neil, Jonathan; Carlson, Richard W; Francis, Don; Stevenson, Ross K

    2008-09-26

    Neodymium-142 data for rocks from the Nuvvuagittuq greenstone belt in northern Quebec, Canada, show that some rock types have lower 142Nd/144Nd ratios than the terrestrial standard (epsilon142Nd = -0.07 to -0.15). Within a mafic amphibolite unit, 142Nd/144Nd ratios correlate positively with Sm/Nd ratios and produce a 146Sm-142Nd isochron with an age of 4280(-81)(+53) million years. These rocks thus sample incompatible-element-enriched material formed shortly after Earth formation and may represent the oldest preserved crustal section on Earth.

  9. Wettability studies of topologically distinct titanium surfaces.

    PubMed

    Kulkarni, Mukta; Patil-Sen, Yogita; Junkar, Ita; Kulkarni, Chandrashekhar V; Lorenzetti, Martina; Iglič, Aleš

    2015-05-01

    Biomedical implants made of titanium-based materials are expected to have certain essential features including high bone-to-implant contact and optimum osteointegration, which are often influenced by the surface topography and physicochemical properties of titanium surfaces. The surface structure in the nanoscale regime is presumed to alter/facilitate the protein binding, cell adhesion and proliferation, thereby reducing post-operative complications with increased lifespan of biomedical implants. The novelty of our TiO2 nanostructures lies mainly in the high level control over their morphology and roughness by mere compositional change and optimisation of the experimental parameters. The present work focuses on the wetting behaviour of various nanostructured titanium surfaces towards water. Kinetics of contact area of water droplet on macroscopically flat, nanoporous and nanotubular titanium surface topologies was monitored under similar evaporation conditions. The contact area of the water droplet on hydrophobic titanium planar surface (foil) was found to decrease during evaporation, whereas the contact area of the droplet on hydrophobic nanorough titanium surfaces practically remained unaffected until the complete evaporation. This demonstrates that the surface morphology and roughness at the nanoscale level substantially affect the titanium dioxide surface-water droplet interaction, opposing to previous observations for microscale structured surfaces. The difference in surface topographic nanofeatures of nanostructured titanium surfaces could be correlated not only with the time-dependency of the contact area, but also with time-dependency of the contact angle and electrochemical properties of these surfaces.

  10. Synthesis and characterization of hybrid nanostructures produced in the presence of the titanium dioxide and bioactive organic substances by hydrothermal method

    SciTech Connect

    Zima, Tatyana; Baklanova, Natalya; Bataev, Ivan

    2013-02-15

    Hybrid nanostructures produced by hydrothermal treatment of TiO{sub 2} in the presence of bioactive organic substances such as chitosan, aminoterephthalic acid and their mixture have been investigated. Sodium polytitanates as one-dimensional elongated structures with lengths of several hundred of nanometers were obtained in the presence of chitosan and aminoterephthalic acid. With chitosan the elongated nanostructures are formed by successive superposition of structural fragments-nanostrips with well-ordered multilayered morphology and increased distance between successive layers to 1.2 nm. Quite different amorphous products as agglomerates with roundest and rhomboid morphology are formed when the mixture of chitosan and aminoterephthalic acid is added to the reaction system. One can propose that main reason of such behavior is a low rate of diffusion of dissolved Ti(IV) ions in the high viscous mixed chitosan-aminoterephthalic system. An effect of organic substances on the formation, morphology and transformation of various titanates is discussed. - Graphical abstract: The typical images of hybrid nanostructures produced by hydrothermal treatment of TiO{sub 2} in the presence chitosan and mixed chitosan with aminoterephthalic acid. Highlights: Black-Right-Pointing-Pointer Various shapes of TiO{sub 2} based structures can be produced in the presence of organic. Black-Right-Pointing-Pointer An addition of chitosan results in the formation of the elongated nanostructures. Black-Right-Pointing-Pointer These structures have multilayered morphology and increased distance between layers. Black-Right-Pointing-Pointer Different agglomerates are formed when chitosan and aminoterephthalic acid are mixed.

  11. Neodymium nanoparticles: biosynthesis and structural analysis.

    PubMed

    Ascencio, J A; Canizal, G; Medina-Flores, A; Bejar, L; Tavera, L; Matamoros, H; Liu, H B

    2006-04-01

    Small metallic nanoparticles of neodymium are obtained by a facile route based on the biosynthesis and the pH conditions that demonstrate the possibility of obtaining particles of 1-8 nm. The size is controlled by synthesis conditions. Smaller clusters were obtained with pH = 5, while for pH = 10 evidences of nanorods productions are found and this opens the perspective to use this rare-earth element for zero and one dimensional based applications. Using transmission electron microscopy techniques, the size distribution and structure are studied. Density functional theory-based calculations allow the determination of the lowest energy configuration, which is based on the hexagonal bulk symmetry. Theoretical models are used to simulate the high resolution transmission electron microscopy to identify the experimental image, determining that the synthesized nanoparticles reach the lowest energy hexagonal configurations.

  12. Selective recognition of neodymium (III) using ion imprinted polymer particles.

    PubMed

    Krishna, Paramesamangalam Gopi; Gladis, Joseph Mary; Rao, Talasila Prasada; Naidu, Gurijala Ramakrishna

    2005-01-01

    Neodymium (III) ion-imprinted polymer (IIP) materials were prepared by the copolymerization of neodymium (III)-5,7-dichloroquinoline-8-ol-4-vinylpyridine ternary complex with styrene(monomer), divinyl benzene (crosslinking monomer) in the presence of 2,2'-azobisisobutyronitrile (initiator). The synthesis was carried out in 2-methoxy ethanol medium (porogen) and the resultant material was filtered, washed, dried and powdered to form unleached IIP particles. The imprint ion was removed by stirring the above particles with 50% (v/v) HCl for 6 h to obtain leached IIP particles with cavities in the polymer particles. Control polymer (CP) particles were similarly prepared without imprint ion, i.e. neodymium (III). CP, unleached and leached IIP particles were characterized by TLC, IR, microanalysis, XRD and UV-visible spectrophotometric studies. The preconcentration of 5-150 microg of neodymium (III) ions present in 500 ml of solution was possible with as little as 40 mg of neodymium (III) IIP particles in the pH range 7.5-8.0 with a detection limit of 50 ng/l. Five replicate determinations of 25 microg of neodymium (III) present in 500 ml of solution gave a mean absorbance of 0.120 with a relative standard deviation of 2.65%. The imprinting effect of IIP particles was noticed in all preconcentration and selectivity studies when compared with CP particles. Furthermore, the selectivity coefficients of neodymium (III) IIP particles were much higher compared with the reported separation factors for the best liquid-liquid extractants, viz. di-2-ethylhexyl phosphoric acid and 2-ethylhexyl-ethylhexyl phosphonate. Kinetic and isotherm studies during rebinding of neodymium (III) onto IIP particles were also carried out.

  13. Neodymium YAG Lasers. Citations from the NTIS data base

    NASA Astrophysics Data System (ADS)

    Carrigan, B.

    1980-07-01

    Federally funded research reports on lasing of neodymium doped yttrium aluminum garnet are cited. Studies on design, fabrication, quantum efficiency, light pulses, stabilization, and testing are covered. Optical pumping, mode locking, frequency conversion, and modulation of these lasers are discussed. Laser applications such as optical communication, range finding, and tracking are included. Safety hazards and radiation damage related to neodymium YAG lasers are also covered. This updated bibliography contains 181 citations, 15 of which are new entries to the previous edition.

  14. Titanate and titania nanostructures and nanostructure assemblies, and methods of making same

    DOEpatents

    Wong, Stanislaus S; Mao, Yuanbing

    2013-05-14

    The invention relates to nanomaterials and assemblies including, a micrometer-scale spherical aggregate comprising: a plurality of one-dimensional nanostructures comprising titanium and oxygen, wherein the one-dimensional nanostructures radiate from a hollow central core thereby forming a spherical aggregate.

  15. Titanate and titania nanostructures and nanostructure assemblies, and methods of making same

    SciTech Connect

    Wong, Stanislaus S.; Mao, Yuanbing

    2016-06-14

    The invention relates to nanomaterial's and assemblies including, a micrometer-scale spherical aggregate comprising: a plurality of one-dimensional nanostructures comprising titanium and oxygen, wherein the one-dimensional nanostructures radiate from a hollow central core thereby forming a spherical aggregate.

  16. A Closer Look at a Stronger Titanium

    ScienceCinema

    Joshi, Vineet; Devaraj, Arun

    2016-09-02

    An improved titanium alloy – stronger than any commercial titanium alloy currently on the market – gets its strength from the novel way atoms are arranged to form a special nanostructure. For the first time, researchers at Pacific Northwest National Laboratory have been able to see this alignment and then manipulate it to make it even stronger. Using powerful electron microscopes and a unique atom probe imaging approach at EMSL, the Environmental Molecular Sciences Laboratory, a DOE Office of Science User Facility located at PNNL, they were able to peer deep inside the alloy’s nanostructure to see what was happening.

  17. A Closer Look at a Stronger Titanium

    SciTech Connect

    Joshi, Vineet; Devaraj, Arun

    2016-04-01

    An improved titanium alloy – stronger than any commercial titanium alloy currently on the market – gets its strength from the novel way atoms are arranged to form a special nanostructure. For the first time, researchers at Pacific Northwest National Laboratory have been able to see this alignment and then manipulate it to make it even stronger. Using powerful electron microscopes and a unique atom probe imaging approach at EMSL, the Environmental Molecular Sciences Laboratory, a DOE Office of Science User Facility located at PNNL, they were able to peer deep inside the alloy’s nanostructure to see what was happening.

  18. Titanium 2013

    USGS Publications Warehouse

    2014-01-01

    Titanium is the ninth most abundant element in the earth's crust and can be found in nearly all rocks and sediments. It is a lithophile element with a strong affinity for oxygen and is not found as a pure metal in nature. Titanium was first isolated as a pure metal in 1910, but it was not until 1948 that the metal was produced commercially using the Kroll process (named after its developer, William Kroll) to reduce titanium tetrachloride with magnesium to produce titanium metal.

  19. Mixed titanium, silicon, and aluminum oxide nanostructures as novel adsorbent for removal of rhodamine 6G and methylene blue as cationic dyes from aqueous solution.

    PubMed

    Pal, Umapada; Sandoval, Alberto; Madrid, Sergio Isaac Uribe; Corro, Grisel; Sharma, Vivek; Mohanty, Paritosh

    2016-11-01

    Mixed oxide nanoparticles containing Ti, Si, and Al of 8-15 nm size range were synthesized using a combined sol-gel - hydrothermal method. Effects of composition on the structure, morphology, and optical properties of the nanoparticles were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), microRaman spectroscopy, and diffuse reflectance spectroscopy (DRS). Dye removal abilities of the nanoparticles from aqueous solutions were tested for different cationic dyes. While all the mixed oxide nanoparticles revealed high and fast adsorption of cationic dyes, the particles containing Ti and Si turned out to be the best. The adsorption kinetics and equilibrium adsorption behavior of the adsorbate - adsorbent systems could be well described by pseudo-second-order kinetics and Langmuir isotherm model, respectively. Estimated thermodynamic parameters revealed the adsorption process is spontaneous, driven mainly by the electrostatic force between the cationic dye molecules and negative charge at nanoparticle surface. Highest dye adsorption capacity (162.96 mg MB/g) of the mixed oxide nanostructures containing Ti and Si is associated to their high specific surface area, and the presence of surface Si-O(δ-) groups, in addition to the hydroxyl groups of amorphous titania. Mixed oxide nanoparticles containing 75% Ti and 25% Si seen to be the most efficient adsorbents for removing cationic dye molecules from wastewater.

  20. Synthesis of Nanostructured Carbides of Titanium and Vanadium from Metal Oxides and Ferroalloys Through High-energy Mechanical Milling and Heat Treatment

    NASA Astrophysics Data System (ADS)

    Basu, P.; Jian, P. F.; Seong, K. Y.; Seng, G. S.; Masrom, A. K.; Hussain, Z.; Aziz, A.

    2010-03-01

    Carbides of Ti and V have been synthesized directly from their oxides and ferroalloys through mechanical milling and heat treatment. The powder mixtures are milled in a planetary ball mill from 15-80 hours and subsequently heat treated at 1000-1300° C for TiO2-C mixtures, at 500-550° C for V2O5-C mixtures and at 600-1000° C for (Fe-V)-C mixtures. The milled and heat treated powders are characterized by SEM, EDAX, XRD, and BET techniques. Nanostructured TiC has been successfully synthesized under suitable processing conditions. However, carbides of vanadium is unidentified even though possibilities of V2O5-C reaction are indicated with an extent of induced amorphism in the powder mixture. Density, specific surface area and particle size of the milled and heat treated mixtures are correlated with heat treatment temperatures. Similar attempts are also made to synthesize vanadium carbides from industrial grade Fe-V.

  1. Boundary processes traced by neodymium isotopes

    NASA Astrophysics Data System (ADS)

    Jeandel, C.; Lacan, F.

    2003-04-01

    Continental margins have been identified as preferential sites for removing of reactive elements from the ocean, on the base of U-series measurements (more specifically 231Pa/230Th). This process is called boundary scavenging (Bacon, 1988). Five years of neodymium isotopes data in water masses along the ocean margins (Indonesia, Papua New Guinea, Greenland-Scotland ridge and Labrador Sea) suggests that Nd is transferred from the sediments to the ocean but the reverse also occurs via the so-called boundary scavenging. These processes are only detectable by isotopic ratio measurements because they affect the isotopic signature of the water mass coming in contact with the margin, without changing its concentration. They can involve much higher fluxes than net input processes: for example, the modification of the AAIW signature along the Papua New Guinea slope involves exchange processes only (Lacan and Jeandel, 2001). Since we suspect that such processes not only affect the Nd oceanic chemistry but also the chemical fate of other reactive elements in the ocean, we suggest that the concept of boundary scavenging should be extended to "boundary exchange".

  2. Process for synthesizing titanium carbide, titanium nitride and titanium carbonitride

    DOEpatents

    Koc, Rasit; Glatzmaier, Gregory C.

    1995-01-01

    A process for synthesizing titanium carbide, titanium nitride or titanium carbonitride. The process comprises placing particles of titanium, a titanium salt or titanium dioxide within a vessel and providing a carbon-containing atmosphere within the vessel. The vessel is heated to a pyrolysis temperature sufficient to pyrolyze the carbon to thereby coat the particles with a carbon coating. Thereafter, the carbon-coated particles are heated in an inert atmosphere to produce titanium carbide, or in a nitrogen atmosphere to produce titanium nitride or titanium carbonitride, with the heating being of a temperature and time sufficient to produce a substantially complete solid solution.

  3. Process for synthesizing titanium carbide, titanium nitride and titanium carbonitride

    DOEpatents

    Koc, R.; Glatzmaier, G.C.

    1995-05-23

    A process is disclosed for synthesizing titanium carbide, titanium nitride or titanium carbonitride. The process comprises placing particles of titanium, a titanium salt or titanium dioxide within a vessel and providing a carbon-containing atmosphere within the vessel. The vessel is heated to a pyrolysis temperature sufficient to pyrolyze the carbon to thereby coat the particles with a carbon coating. Thereafter, the carbon-coated particles are heated in an inert atmosphere to produce titanium carbide, or in a nitrogen atmosphere to produce titanium nitride or titanium carbonitride, with the heating being of a temperature and time sufficient to produce a substantially complete solid solution.

  4. Samarium-neodymium direct dating of fluorite mineralization.

    PubMed

    Chesley, J T; Halliday, A N; Scrivener, R C

    1991-05-17

    The direct dating of many styles of hydrothermal mineralization has proved difficult, limiting understanding of the geological processes that lead to crustal fluid flow and the formation of major ore deposits. The hydrothermal mineral fluorite (CaF(2)) displays large variations in rare earth element (REE) abundance and samarium/neodymium ratios within a single vein. Samarium-neodymium dating of fluorite from the classic granite-hosted tin deposits of southwest England demonstrates its use as a precise chronometer of mineralization. The concentrations of light rare earth elements (LREEs) in the fluorites are highly variable and suggest the coeval precipitation of an LREE-rich phase as the most likely cause of the extreme variation in samarium/neodymium ratios.

  5. New high-strength neodymium phosphate laser glass

    SciTech Connect

    Galagan, B I; Glushchenko, I N; Denker, B I; Kalachev, Yu L; Mikhailov, Viktor A; Sverchkov, S E; Shcherbakov, Ivan A; Kuleshov, N V

    2009-12-31

    A high-strength neodymium laser glass (SNLG) based on an alumoborophosphate composition is developed and synthesised; its physicochemical, spectral, luminescent, and lasing characteristics are studied. It is found that the chemical stability and thermal resistance of the new glass are considerably higher than the corresponding characteristics of known neodymium-doped phosphate laser glasses. Investigations of lasing upon longitudinal diode pumping showed that, due to the higher thermal resistance, the new glass allows one to obtain output powers twice as high as those of industrial GLS22 glass. (active media)

  6. Neodymium-YAG transscleral cyclophotocoagulation. The role of pigmentation

    SciTech Connect

    Cantor, L.B.; Nichols, D.A.; Katz, L.J.; Moster, M.R.; Poryzees, E.; Shields, J.A.; Spaeth, G.L. )

    1989-08-01

    Using a rabbit model we investigated the role of pigmentation of the ciliary body in obtaining ciliodestruction by neodymium-YAG transscleral cyclophotocoagulation. There was marked destruction of the ciliary body in pigmented rabbit eyes, but no histologic effect was observed in albino rabbit eyes. These findings suggest that pigmentation of the ciliary body is important for obtaining the desired response from neodymium-YAG transscleral cyclophotocoagulation in rabbit eyes by our technique. Further study is necessary to define the role of pigmentation in human eyes in this treatment modality.

  7. Recycling potential of neodymium: the case of computer hard disk drives.

    PubMed

    Sprecher, Benjamin; Kleijn, Rene; Kramer, Gert Jan

    2014-08-19

    Neodymium, one of the more critically scarce rare earth metals, is often used in sustainable technologies. In this study, we investigate the potential contribution of neodymium recycling to reducing scarcity in supply, with a case study on computer hard disk drives (HDDs). We first review the literature on neodymium production and recycling potential. From this review, we find that recycling of computer HDDs is currently the most feasible pathway toward large-scale recycling of neodymium, even though HDDs do not represent the largest application of neodymium. We then use a combination of dynamic modeling and empirical experiments to conclude that within the application of NdFeB magnets for HDDs, the potential for loop-closing is significant: up to 57% in 2017. However, compared to the total NdFeB production capacity, the recovery potential from HDDs is relatively small (in the 1-3% range). The distributed nature of neodymium poses a significant challenge for recycling of neodymium.

  8. Efficient wide-aperture neodymium glass rod amplifiers

    SciTech Connect

    Potemkin, A K; Zhurin, K A; Kirsanov, A V; Kopelovich, E A; Kuznetsov, M V; Kuz'min, A A; Flat, F A; Khazanov, Efim A; Shaikin, A A

    2011-06-30

    Amplifiers based on neodymium phosphate glass rods 60 - 100 mm in diameter are experimentally studied. The amplifiers are pumped by INP-16/250 tubular flash lamps placed in a universal pump cavity with a two-section mirror reflector. A compact high-voltage capacitive energy storage with a preionisation circuit was developed to supply the lamps. (lasers)

  9. Purification of cerium, neodymium and gadolinium for low background experiments

    NASA Astrophysics Data System (ADS)

    Boiko, R. S.; Barabash, A. S.; Belli, P.; Bernabei, R.; Cappella, F.; Cerulli, R.; Danevich, F. A.; Incicchitti, A.; Laubenstein, M.; Mokina, V. M.; Nisi, S.; Poda, D. V.; Polischuk, O. G.; Tretyak, V. I.

    2014-01-01

    Cerium, neodymium and gadolinium contain double beta active isotopes. The most interesting are 150Nd and 160Gd (promising for 0ν2β search), 136Ce (2β+ candidate with one of the highest Q2β). The main problem of compounds containing lanthanide elements is their high radioactive contamination by uranium, radium, actinium and thorium. The new generation 2β experiments require development of methods for a deep purification of lanthanides from the radioactive elements. A combination of physical and chemical methods was applied to purify cerium, neodymium and gadolinium. Liquid-liquid extraction technique was used to remove traces of Th and U from neodymium, gadolinium and for purification of cerium from Th, U, Ra and K. Co-precipitation and recrystallization methods were utilized for further reduction of the impurities. The radioactive contamination of the samples before and after the purification was tested by using ultra-low-background HPGe gamma spectrometry. As a result of the purification procedure the radioactive contamination of gadolinium oxide (a similar purification efficiency was reached also with cerium and neodymium oxides) was decreased from 0.12 Bq/kg to 0.007 Bq/kg in 228Th, from 0.04 Bq/kg to <0.006 Bq/kg in 226Ra, and from 0.9 Bq/kg to 0.04 Bq/kg in 40K. The purification methods are much less efficient for chemically very similar radioactive elements like actinium, lanthanum and lutetium.

  10. Materials flow analysis of neodymium, status of rare earth metal in the Republic of Korea.

    PubMed

    Swain, Basudev; Kang, Leeseung; Mishra, Chinmayee; Ahn, JoongWoo; Hong, Hyun Seon

    2015-11-01

    Materials flow analysis of neodymium, status of rare earth elements (REEs) in the Republic of Korea has been investigated. Information from various resources like the Korean Ministry of Environment, Korea international trade association, United Nations Commodity Trade Statistics Database and from individual industry were collected and analyzed for materials flow analysis of neodymium. Demand of neodymium in the Republic of Korea for the year 2010 was 409.5 tons out of which the majority of neodymium, i.e., 68.41% was consumed by domestic electronics industry followed by medical appliances manufacturing (13.36%). The Republic Korea is one of the biggest consumer and leading exporter of these industrial products, absolutely depends on import of neodymium, as the country is lacking natural resources. The Republic of Korea has imported 325.9 tons of neodymium permanent magnet and 79.5 tons of neodymium containing equipment parts mainly for electronics, medical appliances, and heavy/light vehicles manufacturing industry. Out of which 95.4 tons of neodymium permanent magnet get exported as an intermediate product and 140.6 tons of neodymium in the form of consumable products get exported. Worldwide the neodymium is at the high end of supply chain critical metal because of increasing demand, scarcity and irreplaceable for technological application. To bring back the neodymium to supply stream the recycling of end of life neodymium-bearing waste can be a feasible option. Out of total domestic consumption, only 21.9 tons of neodymium have been collected and subsequently recycled. From material flow analysis, the requirement for an efficient recycling system and element-wise material flow management for these REEs in the Republic of Korea were realized and recommended.

  11. Spectroscopic Properties of Neodymium and Erbium-Doped Magnesium Oxide Ceramics

    DTIC Science & Technology

    2015-09-01

    ARL-TR-7441 ● SEPT 2015 US Army Research Laboratory Spectroscopic Properties of Neodymium and Erbium-Doped Magnesium Oxide...Laboratory Spectroscopic Properties of Neodymium and Erbium-Doped Magnesium Oxide Ceramics by T Sanamyan and M Dubinskii Sensors and...REPORT DATE (DD-MM-YYYY) Sep 2015 2. REPORT TYPE Final 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE Spectroscopic Properties of Neodymium

  12. Neodymium-YAG laser vitreolysis in sickle cell retinopathy

    SciTech Connect

    Hrisomalos, N.F.; Jampol, L.M.; Moriarty, B.J.; Serjeant, G.; Acheson, R.; Goldberg, M.F.

    1987-08-01

    Six patients with proliferative sickle cell retinopathy and vitreous bands were treated with the neodymium-YAG (Nd-YAG) laser to accomplish lysis of avascular traction bands or to clear the media in front of the macula. Transection of bands was possible in five of the six cases but in two of these the effect was only partial. Three cases were satisfactorily treated with the Nd-YAG laser application alone, two eventually required conventional vitreoretinal surgery, and one patient's condition stabilized despite failure of the treatment. Complications from the treatment occurred in three cases and included subretinal (choroidal) hemorrhage, preretinal hemorrhage, microperforation of a retinal vein, and focal areas of damage to the retinal pigment epithelium. Neodymium-YAG vitreolysis may be a useful modality in carefully selected patients with proliferative sickle cell retinopathy, but potentially sight-threatening complications may occur.

  13. Chromatographic separation of neodymium isotopes by using chemical exchange process.

    PubMed

    Ismail, I M; Ibrahim, M; Aly, H F; Nomura, M; Fujii, Y

    2011-05-20

    The neodymium isotope effects were investigated in Nd-malate ligand exchange system using the highly porous cation exchange resin SQS-6. The temperature of the chromatographic columns was kept constant at 50°C by temperature controlled water passed through the columns jackets. The separation coefficient of neodymium isotopes, ɛ's, was calculated from the isotopic ratios precisely measured by means of an ICP mass spectrometer equipped with nine collectors as ion detectors. The separation coefficient, ɛ×10(5), were calculated and found to be 1.4, 4.8, 5.4, 10.6, 16.8 and 20.2 for (143)Nd, (144)Nd, (145)Nd, (146)Nd, (148)Nd and (150)Nd, respectively.

  14. Dissociation of cerium(III) and neodymium(III) phthalocyanines

    NASA Astrophysics Data System (ADS)

    Lomova, T. N.

    2015-07-01

    The kinetics of dissociation of phthalocyanine complexes with cerium(III) and neodymium(III) (X)LnPc (X = Cl-, Br-, AcO-) under the action of acetic acid in ethanol with isolation of the macrocyclic ligand depending on the temperature was studied. The kinetic equations with the numerical values of rate constants, activation parameters, and the stoichiometric mechanisms with the limiting simple reaction between the nonionized AcOH molecule and (phthalocyaninato)lanthanide(III) in the axially coordinated ((X)LnPc, cerium complexes) or axially ionized ([(AcOH)LnPc]+X-, neodymium complexes) state were derived by solving the direct and inverse problems. As shown by a comparative analysis of quantitative kinetic data, the state is determined by the electronic structure of the metal cation and the mutual effect of the axial and equatorial ligands in the first coordination sphere.

  15. [Neodymium magnet injury causing nasal fracture: a case report].

    PubMed

    Aykan, Andaç; Güzey, Serbülent; Avşar, Sedat; Öztürk, Serdar

    2015-05-01

    In parallel with technological developments, small size but strong magnets are commonly used in modern devices. In terms of foreign body injuries, magnet injuries are quite rare. However, due to their unique characteristics, there are some difficulties in their management. The magnetic field generated by the magnet affects the surgical instruments and make treatment difficult. In this case report, a nasal injury due to neodymium magnet and our alternative approach for its management was reported.

  16. Comment on "Neodymium-142 evidence for Hadean mafic crust".

    PubMed

    Andreasen, Rasmus; Sharma, Mukul

    2009-07-17

    O'Neil et al. (Reports, 26 September 2008, p. 1828) presented neodymium-142 data for rocks from northern Quebec, Canada, and suggested that these rocks may represent the oldest preserved crustal section on Earth. We argue that the age of the rocks is based on a spurious correlation between rocks that are probably not co-genetic and negative (142)Nd anomalies that may be the result of an analytical artifact.

  17. Titanium Cranioplasty

    PubMed Central

    Gordon, D. S.; Blair, G. A. S.

    1974-01-01

    The technique of repairing defects of the skull with titanium is described. The skull contour can be accurately reproduced. The technique is simpler than wiring or suturing methods. The material is inert, radiolucent, and rigid. ImagesFIG. 1FIG. 2FIG. 3FIG. 5FIG. 6FIG. 7 PMID:4834099

  18. Complexation of di-amides of dipicolinic acid with neodymium

    SciTech Connect

    Lapka, J.L.; Paulenova, A.

    2013-07-01

    Di-amides have undergone significant studies as possible ligands for use in the partitioning of trivalent minor actinides and lanthanides. The binding affinities of three isomeric ligands with neodymium in acetonitrile solution have been investigated. The stability constants of the metal-ligand complexes formed between different isomers of N,N'-diethyl-N,N'- ditolyl-di-picolinamide (EtTDPA) and trivalent neodymium in acetonitrile have been determined by spectrophotometric and calorimetric methods. Each isomer of EtTDPA has been found to be capable of forming three complexes with trivalent neodymium, Nd(EtTDPA), Nd(EtTDPA){sub 2}, and Nd(EtTDPA){sub 3}. Values from spectrophotometric and calorimetric titrations are within reasonable agreement with each other. The order of stability constants for each metal:ligand complex decreases in the order Et(m)TDPA > Et(p)TDPA > Et(o)TDPA. The obtained values are comparable to other di-amidic ligands obtained under similar system conditions and mirror previously obtained solvent extraction data for EtTDPA at low ionic strengths. (authors.

  19. Generation of nanostructures on metals by laser ablation in liquids: new results

    SciTech Connect

    Barmina, E V; Shafeev, Georgii A; Stratakis, E; Fotakis, K

    2010-12-29

    Surface nanostructuring of titanium, nickel, molybdenum, and tungsten by ablation with pico- and femtosecond laser pulses in liquids is studied experimentally for the first time. The morphology and properties of obtained nanostructures are investigated using a field emission scanning electron microscope and Raman spectroscopy. The size of nanostructures depends on the laser pulse duration and energy density and on the target material. As a rule, the size distribution of structures is bimodal. Potential applications of such nanostructured substrates are discussed. (photonics and nanotechnology)

  20. Superhydrophilic nanostructure

    DOEpatents

    Mao, Samuel S; Zormpa, Vasileia; Chen, Xiaobo

    2015-05-12

    An embodiment of a superhydrophilic nanostructure includes nanoparticles. The nanoparticles are formed into porous clusters. The porous clusters are formed into aggregate clusters. An embodiment of an article of manufacture includes the superhydrophilic nanostructure on a substrate. An embodiment of a method of fabricating a superhydrophilic nanostructure includes applying a solution that includes nanoparticles to a substrate. The substrate is heated to form aggregate clusters of porous clusters of the nanoparticles.

  1. An improved biofunction of titanium for keratoprosthesis by hydroxyapatite-coating.

    PubMed

    Dong, Ying; Yang, Jingxin; Wang, Liqiang; Ma, Xiao; Huang, Yifei; Qiu, Zhiye; Cui, Fuzhai

    2014-03-01

    Titanium framework keratoprosthesis has been commonly used in the severe corneal blindness, but the tissue melting occurred frequently around titanium. Since hydroxyapatite has been approved to possess a good tissue integration characteristic, nanostructured hydroxyapatite was coated on the surface of titanium through the aerosol deposition method. In this study, nanostructured hydroxyapatite coating was characterized by X-ray diffraction, scanning electron microscopy, atomic force microscopy, and auger electronic spectrometer. Biological evaluations were performed with rabbit cornea fibroblast in vitro and an animal model in vivo. The outcomes showed the coating had a grain-like surface topography and a good atomic mixed area with substrate. The rabbit cornea fibroblasts appeared a good adhesion on the surface of nanostructured hydroxyapatite in vitro. In the animal model, nanostructured hydroxyapatite-titanium implants were stably retained in the rabbit cornea, and by contrast, the corneal stroma became thinner anterior to the implants in the control. Therefore, our findings proved that nanostructured hydroxyapatite-titanium could not only provide an improved bond for substrate but also enhance the tissue integration with implants in host. As a promising material, nanostructured hydroxyapatite-titanium-based keratoprosthesis prepared by the aerosol deposition method could be utilized for the corneal blindness treatment.

  2. Preparation of titanium diboride powder

    DOEpatents

    Brynestad, Jorulf; Bamberger, Carlos E.

    1985-01-01

    Finely-divided titanium diboride or zirconium diboride powders are formed by reacting gaseous boron trichloride with a material selected from the group consisting of titanium powder, zirconium powder, titanium dichloride powder, titanium trichloride powder, and gaseous titanium trichloride.

  3. Metal Bonded Titanium Diboride

    DTIC Science & Technology

    1952-03-01

    of specimens made from titanium diboride plus 10 percent titanium and 30 percent zirconium . X 100. 22 6. Microstructures of specimens made from...chromium. X 1000 26 10. Microstructures of specimens made from titanium diboride plus 10 percent titanium and 30 percent zirconium . X 1200 27 11. Gain in...shock resistance and oxidation resistance of titanium diboride but zirconium diboride which is isomorphous with titanium diboride has been reported6

  4. Isotope effects of neodymium in different ligands exchange systems studied by ion exchange displacement chromatography.

    PubMed

    Ismail, Ibrahim; Fawzy, Ahmed S; Ahmad, Mohammad I; Aly, Hisham F; Nomura, Masao; Fujii, Yasuhiko

    2013-03-01

    The isotope effects of neodymium in Nd-glycolate ligand exchange system were studied by using ion exchange chromatography. The separation coefficients of neodymium isotopes, ε's, were calculated from the observed isotopic ratios at the front and rear boundaries of the neodymium adsorption band. The values of separation coefficients of neodymium isotopes, ε's, for the Nd-glycolate ligand exchange system were compared with those of Nd-malate and Nd-citrate, which indicated that the isotope effects of neodymium as studied by the three ligands takes the following direction Malate > Citrate > Glycolate. This order agrees with the number of available sites for complexation of each ligand. The values of the plate height, HETP of Nd in Nd-ligand exchange systems were also calculated.

  5. Isotope effects of neodymium in different ligands exchange systems studied by ion exchange displacement chromatography

    PubMed Central

    Ismail, Ibrahim; Fawzy, Ahmed S.; Ahmad, Mohammad I.; Aly, Hisham F.; Nomura, Masao; Fujii, Yasuhiko

    2012-01-01

    The isotope effects of neodymium in Nd-glycolate ligand exchange system were studied by using ion exchange chromatography. The separation coefficients of neodymium isotopes, ε’s, were calculated from the observed isotopic ratios at the front and rear boundaries of the neodymium adsorption band. The values of separation coefficients of neodymium isotopes, ε’s, for the Nd-glycolate ligand exchange system were compared with those of Nd-malate and Nd-citrate, which indicated that the isotope effects of neodymium as studied by the three ligands takes the following direction Malate > Citrate > Glycolate. This order agrees with the number of available sites for complexation of each ligand. The values of the plate height, HETP of Nd in Nd-ligand exchange systems were also calculated. PMID:25685410

  6. Do foraminifera accurately record seawater neodymium isotope composition?

    NASA Astrophysics Data System (ADS)

    Scrivner, Adam; Skinner, Luke; Vance, Derek

    2010-05-01

    Palaeoclimate studies involving the reconstruction of past Atlantic meridional overturning circulation increasingly employ isotopes of neodymium (Nd), measured on a variety of sample media (Frank, 2002). In the open ocean, Nd isotopes are a conservative tracer of water mass mixing and are unaffected by biological and low-temperature fractionation processes (Piepgras and Wasserburg, 1987; Lacan and Jeandel, 2005). For decades, benthic foraminifera have been widely utilised in stable isotope and geochemical studies, but have only recently begun to be exploited as a widely distributed, high-resolution Nd isotope archive (Klevenz et al., 2008), potentially circumventing the difficulties associated with other methods used to recover past deep-water Nd isotopes (Klevenz et al., 2008; Rutberg et al., 2000; Tachikawa et al., 2004). Thus far, a single pilot study (Klevenz et al., 2008) has indicated that core-top sedimentary benthic foraminifera record a Nd isotope composition in agreement with the nearest available bottom seawater data, and has suggested that this archive is potentially useful on both millennial and million-year timescales. Here we present seawater and proximal core-top foraminifer Nd isotope data for samples recovered during the 2008 "RETRO" cruise of the Marion Dufresne. The foraminifer samples comprise a depth-transect spanning 3000m of the water column in the Angola Basin and permit a direct comparison between high-resolution water column and core-top foraminiferal Nd isotope data. We use these data to assess the reliability of both planktonic and benthic foraminifera as recorders of water column neodymium isotope composition. Frank, M., 2002. Radiogenic isotopes: Tracers of past ocean circulation and erosional input, Rev. Geophys., 40 (1), 1001, doi:10.1029/2000RG000094. Klevenz, V., Vance, D., Schmidt, D.N., and Mezger, K., 2008. Neodymium isotopes in benthic foraminifera: Core-top systematics and a down-core record from the Neogene south Atlantic

  7. Synthesis of Samarium-Titanium and Neodymium Iron-Boron Magnetic Films with Special Anisotropies.

    NASA Astrophysics Data System (ADS)

    Wickramasekara, Lee

    Rare earth-transition metal film magnets of Nd -Fe-B and several new phases of Sm-Ti-Fe system have been synthesised by special sputtering methods to utilize the high magnetic anisotropies of these alloys. The magnetic properties of these film magnets were observed to be strongly dependent on the film textures. Thus, by varying the sputtering conditions we were able to synthesize films with crystal textures which gives rise to special anisotropies. Crystalline films of Sm(FeTi)(,2) and SmCo(,3) were synthesized with large perpendicular anisotropy of 10('6) erg/cc, whereas (SmTi)Fe(,5) and Sm(,2)(FeCoZr)(,17) were synthesized with inplane anisotropy and static energy product of 20 MG-Oe. The Nd(,2)Fe(,14)B film system is unique due to the fact that it can be synthesized with large perpendicular anisotropy of 1.5 x 10('7) erg/cc with 9 kG remanent and 16 kOe coercive force or inplane anisotropy with 16 MG-Oe static energy product by controlling the sputtering rate. In addition, SmCo(,5), (SmTi)Fe(,5), and Sm(,2)(FeCoZr)(,17) film systems were synthesized in amorphous states in the presence of inplane magnetic field of 2.5 kOe and exhibited large uniaxial inplane anisotropy of 10('6) erg/cc. In particular, upon annealing from the amorphous state in the same magnetic field, the SmCo(,5) phase exhibited a coercive force larger than 22 kOe and its moment could not be rotated within the film plane with a 22 kOe external field, thus increasing the uniaxial inplane anisotropy constant to at least 10('7) erg/cc.

  8. Local immunity in treating skin melanoma by neodymium pulsed laser

    NASA Astrophysics Data System (ADS)

    Moskalik, Konstantin G.

    1997-06-01

    The number and correlation of skin stroma cells was studied on mice C57B1 with the subcutaneously transplanted melanoma B16 which was exposed to neodymium pulsed laser radiation. Within 1-5 days after the exposure the total number of the free skin stroma cells was found to increase in the periphery from the radiation epicenter and the number of lymphocytes, macrophages and leucocytes tended to grow. Lymphoid infiltration was also revealed in the preparations of the epithelized wound and cicatrix on the skin melanoma sites in the patients who had undergone pulsed laser radiation therapy.

  9. Nanostructured materials

    NASA Astrophysics Data System (ADS)

    Moriarty, Philip

    2001-03-01

    Nanostructured materials may be defined as those materials whose structural elements - clusters, crystallites or molecules - have dimensions in the 1 to 100 nm range. The explosion in both academic and industrial interest in these materials over the past decade arises from the remarkable variations in fundamental electrical, optical and magnetic properties that occur as one progresses from an `infinitely extended' solid to a particle of material consisting of a countable number of atoms. This review details recent advances in the synthesis and investigation of functional nanostructured materials, focusing on the novel size-dependent physics and chemistry that results when electrons are confined within nanoscale semiconductor and metal clusters and colloids. Carbon-based nanomaterials and nanostructures including fullerenes and nanotubes play an increasingly pervasive role in nanoscale science and technology and are thus described in some depth. Current nanodevice fabrication methods and the future prospects for nanostructured materials and nanodevices are discussed.

  10. Magnetic behaviour of Neodymium-substituted strontium hexaferrite

    NASA Astrophysics Data System (ADS)

    Bhat, Bilal Hamid; Want, Basharat

    2016-03-01

    Neodymium-substituted strontium hexaferrites, Sr1- x Nd x Fe12O19 ( x = 0, 0.05, 0.10, 0.15, 0.20), have been successfully synthesized by using citrate precursor method. The synthesized samples were characterized by X-ray diffraction, Transmission electron microscopy and vibrating sample magnetometry. The X-ray diffraction results show that the prepared samples are crystalline in nature and are of single phase with the space group P63/mmc. Transmission electron microscopy results show that the prepared sample is composed of fine nanoparticles with an average size of 80 nm. The effect on magnetic behaviour of strontium hexaferrite with neodymium substitution was analysed by using first-order reversal curves (FORCs). FORC analysis was done in order to know the domain state of magnetization of the nanoparticles and the nature of magnetic interactions among the particles. FORC diagrams depict a single peak, suggesting that the substituted systems are formed of interacting nanoparticles.

  11. Hydriding of Titanium.

    DTIC Science & Technology

    1998-03-01

    hole. The metals used to make these couples with titanium included HY80 steel , 316 stainless steel , five-nines aluminum, 6061 aluminum, and zinc. All...the other surfaces. Titanium Coupled With Other Metals The corrosion potentials of grade 2 titanium galvanically coupled with naval brass, HY80 steel ...2 titanium; naval brass caused titanium to become an anode. At room temperature, HY80 steel and 316 stainless steel couples exhibited corrosion

  12. Origin of the Sudbury Complex by meteoritic impact: Neodymium isotopic evidence

    USGS Publications Warehouse

    Faggart, B.E.; Basu, A.R.; Tatsumoto, M.

    1985-01-01

    Samarium-neodymium isotopic data on whole rocks and minerals of the Sudbury Complex in Canada gave an igneous crystallization age of 1840 ?? 21 ?? 106 years. The initial epsilon neodymium values for 15 whole rocks are similar to those for average upper continental crust, falling on the crustal trend of neodymium isotopic evolution as defined by shales. The rare earth element concentration patterns of Sudbury rocks are also similar to upper crustal averages. These data suggest that the Sudbury Complex formed from melts generated in the upper crust and are consistent with a meteoritic impact.

  13. Electrolytic production of neodymium without perfluorinated carbon compounds on the offgases

    DOEpatents

    Keller, Rudolf; Larimer, Kirk T.

    1998-01-01

    A method of producing neodymium in an electrolytic cell without formation of perfluorinated carbon gases (PFCs), the method comprising the steps of providing an electrolyte in the electrolytic cell and providing an anode in an anode region of the electrolyte and providing a cathode in a cathode region of the electrolytic cell. Dissolving an oxygen-containing neodymium compound in the electrolyte in the anode region and maintaining a more intense electrolyte circulation in the anode region than in the cathode region. Passing an electrolytic current between said anode and said cathode and depositing neodymium metal at the cathode, preventing the formation of perfluorinated carbon gases by limiting anode over voltage.

  14. Analysis of the structure and Mössbauer study of the neodymium substitution in the Sr-hexaferrite

    NASA Astrophysics Data System (ADS)

    Pérez-Juache, T. J.; Guerrero, A. L.; Cabal-Velarde, J. G.; Mirabal-García, M.; Palomares-Sánchez, S. A.; Matutes-Aquino, J. A.

    2016-12-01

    This work reads on the obtainment of the strontium hexaferrite substituted with neodymium in its pure phase using the solid state reaction method. The solubility of neodymium on the strontium hexaferrite was investigated according with the formula Sr1-xNdxFe12O19, for x=0.00, 0.05, 0.10, 0.15, 0.20 and 0.25. Results indicate that neodymium is soluble in the hexaferrite until x=0.15. In samples with higher neodymium content there are traces of secondary phases. Analysis of magnetic and structural properties was performed in function of the neodymium content, always in its solubility range. From the structural properties, it was observed that the addition of a little neodymium quantity in the Sr-hexaferrite causes an important reduction of the unit cell volume. Also, magnetic properties are strongly linked to the structural behavior, in this case a trend to reduce the magnetization of the samples was detected when neodymium content increased, which can be explained in terms of fluctuations of the superexchange coupling conducted by the neodymium interactions with the structure. Mössbauer analysis was carried out in order to analyze the effects of the neodymium substitution on the hyperfine parameters, as well as to confirm the preferential site of the neodymium substitution in the Sr-hexaferrite.

  15. Segmental irradiation of the bladder with neodymium YAG laser irradiation

    SciTech Connect

    McPhee, M.S.; Mador, D.R.; Tulip, J.; Ritchie, B.; Moore, R.; Lakey, W.H.

    1982-11-01

    The Neodymium YAG laser energy source can be readily adapted for cystoscopic use by some simple modifications of existing urologic equipment. Both the fiberoptic resectoscope and a deflecting cystourethroscope have been adapted for this purpose. Fixation of the fiber tip 1 cm. from the target and use of a divergent beam of 36 degrees allows the delivery of standardized dosage to a relatively large bladder tissue volume. Animal experiments involving 35 mongrel dogs established that repetitive overlapping doses of 200 joules ech can successfully treat a large area of bladder resulting in a full thickness bladder wall injury. This technique has been used in 4 high risk patients with infiltrating bladder cancer without adverse sequelae. The ability to reliably produce a full thickness lesion may give this modality a therapeutic advantage over conventional cautery techniques especially for the treatment of residual infiltrative carcinoma.

  16. A new contact neodymium: YAG laser for cyclophotocoagulation

    SciTech Connect

    Iwach, A.G.; Drake, M.V.; Hoskins, H.D. Jr.; Schuster, B.L.; Vassiliadis, A.; Crawford, J.B.; Hennings, D.R. )

    1991-06-01

    A newly developed compact (40 kg), self-contained contact Neodymium:YAG laser produces high-peak, high-energy (800 mJ/pulse), short (1.0 millisecond) pulses with 1 to 3 pulses/exposure. Energy is delivered via a 320-microns cleaved quartz fiber optic probe. Cyclophotocoagulation was performed in five eyes of three medium-sized Dutch-pigmented rabbits. The eyes received exposures of 1 to 3 pulses/exposure. Energy delivered ranged from 100 to 800 mJ/pulse. Histopathology revealed ciliary body disruption and hemorrhage with no damage to overlying sclera. When used for transscleral cyclodiathermy in the rabbit, the laser created significant ciliary body disruption with minimal scleral injury.

  17. Absolute isotopic composition and atomic weight of neodymium using thermal ionization mass spectrometry.

    PubMed

    Zhao, Motian; Zhou, Tao; Wang, Jun; Lu, Hai; Fang, Xiang; Guo, Chunhua; Li, Qiuli; Li, Chaofeng

    2005-01-01

    Synthetic mixtures prepared gravimetrically from highly enriched isotopes of neodymium in the form of oxides of well-defined purity were used to calibrate a thermal ionization mass spectrometer. A new error analysis was applied to calculate the final uncertainty of the atomic weight value. Measurements on natural neodymium samples yielded an absolute isotopic composition of 27.153(19) atomic percent (at.%) 142Nd, 12.173(18) at.% 143Nd, 23.798(12) at.% 144Nd, 8.293(7) at.% 145Nd, 17.189(17) at.% 146Nd, 5.756(8) at.% 148Nd, and 5.638(9) at.% 150Nd, and the atomic weight of neodymium as 144.2415(13), with uncertainties given on the basis of 95% confidence limits. No isotopic fractionation was found in terrestrial neodymium materials.

  18. Isotope enrichment by frequency-tripled temperature tuned neodymium laser photolysis of formaldehyde

    DOEpatents

    Marling, John B.

    1977-01-01

    Enrichment of carbon, hydrogen and/or oxygen isotopes by means of isotopically selective photo-predissociation of formaldehyde is achieved by irradiation provided by a frequency-tripled, temperature tuned neodymium laser.

  19. Microscale Demonstration of the Paramagnetism of Liquid Oxygen with a Neodymium Magnet

    ERIC Educational Resources Information Center

    Mattson, Bruce

    2007-01-01

    A microscale classroom demonstration of the paramagnetic behavior of various samples of liquid oxygen with neodymium magnet is being presented. The experiment should be done with extreme caution, as liquid oxygen reacts violently with organic matters.

  20. Modification of neodymium-doped ZnO hybrid nanoparticles under mild hydrothermal conditions.

    PubMed

    Shahmoradi, Behzad; Soga, K; Ananda, S; Somashekar, R; Byrappa, K

    2010-07-01

    The morphology and particle size of neodymium-doped ZnO hybrid nanoparticles were tailored through fabrication under mild hydrothermal conditions (T = 150-250 degrees C, P = autogeneous, t = 18 h) for the first time using two surface modifiers: caprylic acid and n-butylamine. Characterization of these nanoparticles was carried out using powder XRD, FTIR, SEM, zeta-potential analysis and UV-vis spectroscopy. The results revealed that modification of ZnO nanoparticles using neodymium as a dopant and caprylic acid or n-butylamine as a surfactant could change the optical and physical properties of the surface-modified neodymium-doped ZnO hybrid nanoparticles. The work proved the efficiency of caprylic acid and n-butylamine as suitable surfactants for surface modification of neodymium-doped ZnO hybrid nanoparticles.

  1. Description of the traction characteristics of the neodymium compensators of the automatic vibration isolations

    NASA Astrophysics Data System (ADS)

    Gurova, E. G.; Panchenko, Y. V.; Gurov, M. G.

    2016-04-01

    In this paper the method of calculation of neodymium magnets was presented. The calculation of the neodymium magnets characteristics and stiffness correctors of the vibration isolator according to the requirements for vibration isolation devices with stiffness compensators was performed. This research has been performed with the support of the President scholarship for young scientists, order No. 184 of Ministry of education and science of the Russian Federation of the 10th of March 2015.

  2. Neodymium and strontium isotope evidence for crustal contamination of continental volcanics.

    PubMed

    Carter, S R; Evensen, N M; Hamilton, P J; O'nions, R K

    1978-11-17

    Combined neodymium and strontium isotope studies on Tertiary volcanics from northwest Scotland indicate that their parental mantle isotopic compositions have been substantially modified in many instances by contamination with the Precambrian continental crust through which they were erupted. The occurrence of samarium-neodymium and rubidium-strontium "pseudoisochrons" of different ages in these contaminated continental volcanics indicates that they are artifacts of the contamination processes and have no temporal significance with respect to mantle fractionation events.

  3. Research and development of neodymium phosphate laser glass for high power laser application

    NASA Astrophysics Data System (ADS)

    Hu, Lili; He, Dongbing; Chen, Huiyu; Wang, Xin; Meng, Tao; Wen, Lei; Hu, Junjiang; Xu, Yongchun; Li, Shunguang; Chen, Youkuo; Chen, Wei; Chen, Shubin; Tang, Jingping; Wang, Biao

    2016-12-01

    Neodymium phosphate laser glass is a key optical element for high-power laser facility. In this work, the latest research and development of neodymium phosphate laser glass at the Shanghai Institute of Optics and Fine Mechanics (SIOM), China, is addressed. Neodymium phosphate laser glasses, N31, N41, NAP2, and NAP4, for high peak power and high average power applications have been developed. The properties of these glasses are presented and compared to those of other commercial neodymium phosphate laser glass from the Schott and Hoya companies and the Vavilov State Optical Institute (GOI), Russia. Continuous melting and edge cladding are the two key fabrication techniques that are used for the mass production of neodymium phosphate laser glass slabs. These techniques for the fabrication of large-aperture N31 neodymium phosphate laser glass slabs with low stress birefringence and residual reflectivity have been developed by us The effect of acid etching on the microstructure, optical transmission, and mechanical properties of NAP2 glass is also discussed.

  4. Research and development of neodymium phosphate laser glass for high power laser application

    NASA Astrophysics Data System (ADS)

    Hu, Lili; He, Dongbing; Chen, Huiyu; Wang, Xin; Meng, Tao; Wen, Lei; Hu, Junjiang; Xu, Yongchun; Li, Shunguang; Chen, Youkuo; Chen, Wei; Chen, Shubin; Tang, Jingping; Wang, Biao

    2017-01-01

    Neodymium phosphate laser glass is a key optical element for high-power laser facility. In this work, the latest research and development of neodymium phosphate laser glass at the Shanghai Institute of Optics and Fine Mechanics (SIOM), China, is addressed. Neodymium phosphate laser glasses, N31, N41, NAP2, and NAP4, for high peak power and high average power applications have been developed. The properties of these glasses are presented and compared to those of other commercial neodymium phosphate laser glass from the Schott and Hoya companies and the Vavilov State Optical Institute (GOI), Russia. Continuous melting and edge cladding are the two key fabrication techniques that are used for the mass production of neodymium phosphate laser glass slabs. These techniques for the fabrication of large-aperture N31 neodymium phosphate laser glass slabs with low stress birefringence and residual reflectivity have been developed by us The effect of acid etching on the microstructure, optical transmission, and mechanical properties of NAP2 glass is also discussed.

  5. Titanium hermetic seals

    DOEpatents

    Brow, Richard K.; Watkins, Randall D.

    1995-01-01

    Titanium is prenitrided by being heated in a nitrogen environment under conditions which give rise to the formation of a titanium-nitride surface layer on the titanium. Titanium thus prenitrided may be used in electrical components which are hermetically sealed using silicate glasses and standard glass sealing techniques. According to the method of the invention, alkali volatilization and formation of deleterious interfacial silicide are inhibited.

  6. Titanium hermetic seals

    DOEpatents

    Brow, Richard K.; Watkins, Randall D.

    1995-07-04

    Titanium is prenitrided by being heated in a nitrogen environment under conditions which give rise to the formation of a titanium-nitride surface layer on the titanium. Titanium thus prenitrided may be used in electrical components which are hermetically sealed using silicate glasses and standard glass sealing techniques. According to the method of the invention, alkali volatilization and formation of deleterious interfacial silicide are inhibited.

  7. Nanoscale Topography on Black Titanium Imparts Multi-biofunctional Properties for Orthopedic Applications

    PubMed Central

    Hasan, Jafar; Jain, Shubham; Chatterjee, Kaushik

    2017-01-01

    We have developed a chlorine based reactive ion etching process to yield randomly oriented anisotropic nanostructures that render the titanium metal surface ‘black’ similar to that of black silicon. The surface appears black due to the nanostructures in contrast to the conventional shiny surface of titanium. The nanostructures were found to kill bacteria on contact by mechanically rupturing the cells as has been observed previously on wings of certain insects. The etching was optimized to yield nanostructures of ≈1 μm height for maximal bactericidal efficiency without compromising cytocompatibility. Within 4 hours of contact with the black titanium surface, 95% ± 5% of E. coli, 98% ± 2% of P. aeruginosa, 92% ± 5% of M. smegmatis and 22% ± 8% of S. aureus cells that had attached were killed. The killing efficiency for the S. aureus increased to 76% ± 4% when the cells were allowed to adhere up to 24 hours. The black titanium supported the attachment and proliferation of human mesenchymal stem cells and augmented osteogenic lineage commitment in vitro. Thus, the bioinspired nanostructures on black titanium impart multi-biofunctional properties toward engineering the next-generation biomaterials for orthopedic implants. PMID:28112235

  8. Nanoscale Topography on Black Titanium Imparts Multi-biofunctional Properties for Orthopedic Applications

    NASA Astrophysics Data System (ADS)

    Hasan, Jafar; Jain, Shubham; Chatterjee, Kaushik

    2017-01-01

    We have developed a chlorine based reactive ion etching process to yield randomly oriented anisotropic nanostructures that render the titanium metal surface ‘black’ similar to that of black silicon. The surface appears black due to the nanostructures in contrast to the conventional shiny surface of titanium. The nanostructures were found to kill bacteria on contact by mechanically rupturing the cells as has been observed previously on wings of certain insects. The etching was optimized to yield nanostructures of ≈1 μm height for maximal bactericidal efficiency without compromising cytocompatibility. Within 4 hours of contact with the black titanium surface, 95% ± 5% of E. coli, 98% ± 2% of P. aeruginosa, 92% ± 5% of M. smegmatis and 22% ± 8% of S. aureus cells that had attached were killed. The killing efficiency for the S. aureus increased to 76% ± 4% when the cells were allowed to adhere up to 24 hours. The black titanium supported the attachment and proliferation of human mesenchymal stem cells and augmented osteogenic lineage commitment in vitro. Thus, the bioinspired nanostructures on black titanium impart multi-biofunctional properties toward engineering the next-generation biomaterials for orthopedic implants.

  9. Diffusion kinetics of samarium and neodymium in garnet, and a method for determining cooling rates of rocks

    PubMed

    Ganguly; Tirone; Hervig

    1998-08-07

    Experimental determinations of the diffusion coefficients of samarium and neodymium in almandine garnet and theoretical considerations show that one cannot assign a sufficiently restricted range of closure temperature, TC, to the samarium-neodymium decay system in garnet for the purpose of constraining the cooling rate. However, it is shown that the samarium-neodymium cooling age of garnet can be used to calculate both cooling rate and TC if the temperature and age at the peak metamorphic conditions are known.

  10. Sealing glasses for titanium and titanium alloys

    DOEpatents

    Brow, Richard K.; Watkins, Randall D.

    1992-01-01

    Glass compositions containing CaO, Al.sub.2 O.sub.3, B.sub.2 O.sub.3, SrO and BaO of various combinations of mole % are provided. These compositions are capable of forming stable glass-to-metal seals with titanium and titanium alloys, for use in components such as seals for battery headers.

  11. Sealing glasses for titanium and titanium alloys

    DOEpatents

    Brow, R.K.; Watkins, R.D.

    1988-01-21

    Glass compositions containing CaO, Al/sub 2/O/sub 3/, B/sub 2/O/sub 3/, SrO and BaO of various combinations of mole % are provided. These compositions are capable of forming stable glass-to-metal seals with titanium and titanium alloys, for use in components such as seals for battery headers.

  12. Thermoluminescent sensitivity of single clad neodymium doped SiO2 optical fibres measured with 6 MeV photons

    NASA Astrophysics Data System (ADS)

    Saeed, M. A.; Hossain, I.; Hida, N.; Wagiran, H.

    2013-10-01

    This study investigates the thermoluminescent sensitivity of neodymium doped SiO2 optical fibre with various dose ranges from 0.5 Gy to 4.0 Gy by 6 MeV photon irradiations. The TL responses of the neodymium doped silica fibres are compared with available TLD-100 dosimeter in order to determine the suitability as a TL material. We found that the TLD-100 and neodymium doped silica fibre have a significant linear signal to dose relationship. Neodymium doped fibres sensitivity is approximately 11% of TLD-100.

  13. Preparation and characterization of nanostructured titanate bioceramic coating by anodization-hydrothermal method

    NASA Astrophysics Data System (ADS)

    Liu, Qiannan; Liu, Yong; Lei, Ting; Tan, Yanni; Wu, Hong; Li, Jianbo

    2015-02-01

    In this work, nanostructured titanate coatings were prepared on pure titanium substrate by hydrothermal treatment combined with and without anodic oxidation. The morphology and microstructure of coatings were characterized and the corrosion resistance and bioactivity were studied. The results show that the anodization-hydrothermal method is suitable for the formation of nanostructured titanate coating on Ti in concentrated KOH solution. The coatings are composed of K2Ti6O13 and H2Ti2O5·H2O, and can greatly improve the corrosion resistance of Ti substrate. Moreover, the coatings can induce the formation of new apatite layer after the immersion in simulated body fluid, exhibiting good bioactivity. The anodizaiton treatment can not only accelerate the formation of nanostructures, but also can provide nucleation sites for nanostructured titanates, tailoring the morphology of coating. The titanium substrate with nanostructured titanate coating is expected to have significant applications as biomedical materials.

  14. Nanostructured photovoltaics

    NASA Astrophysics Data System (ADS)

    Fu, Lan; Tan, H. Hoe; Jagadish, Chennupati

    2013-01-01

    Energy and the environment are two of the most important global issues that we currently face. The development of clean and sustainable energy resources is essential to reduce greenhouse gas emission and meet our ever-increasing demand for energy. Over the last decade photovoltaics, as one of the leading technologies to meet these challenges, has seen a continuous increase in research, development and investment. Meanwhile, nanotechnology, which is considered to be the technology of the future, is gradually revolutionizing our everyday life through adaptation and incorporation into many traditional technologies, particularly energy-related technologies, such as photovoltaics. While the record for the highest efficiency is firmly held by multijunction III-V solar cells, there has never been a shortage of new research effort put into improving the efficiencies of all types of solar cells and making them more cost effective. In particular, there have been extensive and exciting developments in employing nanostructures; features with different low dimensionalities, such as quantum wells, nanowires, nanotubes, nanoparticles and quantum dots, have been incorporated into existing photovoltaic technologies to enhance their performance and/or reduce their cost. Investigations into light trapping using plasmonic nanostructures to effectively increase light absorption in various solar cells are also being rigorously pursued. In addition, nanotechnology provides researchers with great opportunities to explore the new ideas and physics offered by nanostructures to implement advanced solar cell concepts such as hot carrier, multi-exciton and intermediate band solar cells. This special issue of Journal of Physics D: Applied Physics contains selected papers on nanostructured photovoltaics written by researchers in their respective fields of expertise. These papers capture the current excitement, as well as addressing some open questions in the field, covering topics including the

  15. Femtosecond diode-pumped mode-locked neodymium lasers

    NASA Astrophysics Data System (ADS)

    Kubeček, Václav; Jelínek, Michal; Čech, Miroslav; Vyhlídal, David; Su, Liangbi; Jiang, Dapeng; Ma, Fengkai; Qian, Xiaobo; Wang, Jingya; Xu, Jun

    2016-12-01

    Fluoride-type crystals (CaF2, SrF2) doped with neodymium Nd3+ and codoped with buffer ions for breaking clusters of active ions and increasing fluorescence efficiency, present interesting alternative as laser active media for the diode-pumped mode-locked lasers. In comparison with widely used materials as Nd:YAG or Nd:YVO4, they have broad emission spectra as well as longer fluorescence lifetime, in comparison with Nd:glass, SrF2 and CaF2 have better thermal conductivity. In spite of the fact, that this thermal conductivity decreases with Nd3+ doping concentration, these crystals are alternative for the Nd:glass in subpicosecond mode-locked laser systems. In this paper we review the basic results reported recently on these active materials and in the second part we present our results achieved in low power diode pumped passively mode locked lasers with Nd,La:CaF2 and Nd,Y:SrF2 crystals. The pulses as short as 258 fs at wavelength of 1057 nm were obtained in the first case, while 5 ps long pulses at 1065 nm were generated from the second laser system.

  16. Dielectric and impedance spectroscopic studies of neodymium gallate

    NASA Astrophysics Data System (ADS)

    Sakhya, Anup Pradhan; Dutta, Alo; Sinha, T. P.

    2016-05-01

    The AC electrical properties of a polycrystalline neodymium gallate, NdGaO3 (NGO), synthesized by the sol-gel method have been investigated by employing impedance spectroscopy in the frequency range from 42 Hz to 5 MHz and in the temperature range from 323 K to 593 K. The X-ray diffraction analysis shows that the compound crystallizes in the orthorhombic phase with Pbnm space group at room temperature. Two relaxation processes with different relaxation times are observed from the impedance as well as modulus spectroscopic measurements, which have been attributed to the grain and the grain boundary effects at different temperatures in NGO. The complex impedance data are analyzed by an electrical equivalent circuit consisting of a resistance and a constant phase element in parallel. It has been observed that the value of the capacitance and the resistance associated with the grain boundary is higher than those associated with the grain. The temperature dependent electrical conductivity shows the negative temperature coefficient of resistance. The frequency dependent conductivity spectra are found to follow the power law.

  17. Early tissue response to transscleral neodymium: YAG cyclophotocoagulation.

    PubMed

    Blasini, M; Simmons, R; Shields, M B

    1990-06-01

    Transscleral cyclophotocoagulation was performed with a neodymium: YAG laser on five patients 24-72 hr before enucleation for a blind, painful eye. The thermal mode at 20 ms and a maximum offset between aiming and therapeutic beams were kept constant. Variable parameters evaluated were energy levels between 2 and 8 J and distance from the limbus of 0.5-3.0 mm. Because of the underlying distortion in three of the eyes, meaningful interpretation by light microscopic evaluation was possible only in the other two. This suggested that the early histologic hallmark of the procedure is similar to that previously observed in human autopsy eyes with ciliary epithelial damage and elevation from underlying tissue. In addition, fibrin and scant inflammatory cells were seen in the space between ciliary epithelium and stroma. Minimal damage was observed in the ciliary muscle. These findings suggest that direct damage to the ciliary epithelium is the most likely mechanism of reduced aqueous production by this cyclodestructive procedure. The findings also support the concept that an anterior placement of approximately 1.0-1.5 mm posterior to the limbus is most likely to damage the ciliary epithelium of the pars plicata.

  18. Defluoridation of water using neodymium-modified chitosan.

    PubMed

    Yao, Ruihua; Meng, Fanping; Zhang, Longjun; Ma, Dongdong; Wang, Mingli

    2009-06-15

    The water containing high fluoride ions could do harm to human and environment. In this work, the applicability of neodymium-modified chitosan as adsorbents for the removal of excess fluoride ions from water was studied. The effect of various physico-chemical parameters such as temperature (283-323 K), pH (5-9), adsorbent dose (0.2-2.0 g L(-1)), particle size (0.10-0.50mm) and the presence of co-anions (NO(3)(-), Cl(-) and SO(4)(2-)) on removal of fluoride ions were studied. The equilibrium sorption data were fitted reasonably well for Langmuir isotherm model, the maximum equilibrium sorption had found to be 11.411-22.380 mg g(-1). Sorption dynamics study revealed that the pseudo-second-order was suitable to describe the kinetics process of fluoride ions sorption onto the adsorbent with the initial sorption rate 1.70, 2.10 and 2.67 mg g(-1)min(-1) at 283, 303 and 323 K, and the sorption process was complex, both the boundary of liquid film and intra-particle diffusion contributed to the rate-determining step. The used adsorbents could be regenerated in 24h by 4 g L(-1) of sodium hydroxide.

  19. Effect Of Neodymium Substitution In Structural Characteristics Of Magnesium Ferrite

    SciTech Connect

    Thankachan, Smitha; Binu, P. J.; Xavier, Sheena; Mohammed, E. M.

    2011-10-20

    The effect of Nd{sup 3+} substitution on the structural properties of Magnesium ferrite was studied in the series MgNd{sub x}Fe{sub 2-x}O{sub 4}, where x = 0 to 0.3 in steps of 0.05. The series was prepared by sol-gel technique which is one of the novel technique to prepare nanosized samples. Structural characterization was done using X-ray diffractometer and Fourier Transform Infrared Spectrometer. XRD analysis reveals the prepared samples are single phasic till x = 0.2. From x0 = .25, a secondary phase of iron neodymium oxide appears along with the spinel phase. Particle size calculation shows the prepared samples are in the 9nm to 11 nm regime. Lattice parameter was found to increase with concentration of Nd. XRD and FTIR analysis confirmed spinel structure of the prepared samples. XRF result shows the expected composition of prepared samples. The frequency dependence of the dielectric constant in the range 100 Hz--120MHz was also studied

  20. Dielectric properties of neodymium-modified PLZT ceramics

    NASA Astrophysics Data System (ADS)

    Płońska, M.; Adamczyk, M.

    2015-08-01

    Relaxor ferroelectrics or relaxors are a class of disordered single crystals and ceramic materials, of peculiar structure as well as properties. The commonly known examples of such materials are Pb(Mg,Nb)O3 (PMN) ceramics as well as single crystals. The second most extensively studied relaxor ceramics is lanthanum-doped lead zirconate-titanate, described as x/65/35 PLZT when lanthanum content is x = 6-10 at%. Throughout the last few decades, there has been an increasing interest in rare-earth-doped PLZT ceramics, because PLZT can be easily substituted with lanthanide elements for La3+ ions. For this reason, the present studies concern the changes in microstructure and crystal structure as well as in dielectric properties, caused by modification of 8/65/35 PLZT with neodymium dopant. Modification of this material with Nd3+ influences the microstructure, electrooptical and dielectric properties, whereas the changes in crystal structure are slight. It was also observed that the maximum value of dielectric properties decreases and moves to a low temperature. Described changes in physical properties are associated with the significant improvement of relaxor properties, characteristic for pure 8/65/35 PLZT ceramics.

  1. Transendoscopic neodymium:yttrium aluminum garnet laser irradiation in horses.

    PubMed

    Tate, L P; Sweeney, C L; Cullen, J M; Corbett, W T; Newman, H C; Brown, T C; Ketner, M T

    1989-05-01

    A neodymium:yttrium aluminum garnet (Nd:YAG) laser was used to study effects of applying laser irradiation transendoscopically to the corniculate process of the arytenoid cartilage in horses. Dosimetry was established initially in vitro in 10 corniculate cartilages that were irradiated and examined histologically to determine penetration depths at selected power settings. Eleven horses were given xylazine IV and butorphoral tartrate IV, and their left ventricle and corniculate process were irradiated. Six horses had left laryngeal hemiplegia and were euthanatized and necropsied 14 weeks after laser application and evaluation for upper airway stridor. Endoscopy was performed in the 5 other horses; they were euthanatized and necropsied at selected intervals to characterize the healing process. Healing was by second intention and was complete at 14 weeks. Two horses developed buds of granulation tissue along the laser incision, which resolved after a second laser application. Scar tissue formation resulted in left of midline displacement of the dorsal portion of the right corniculate process. The left ventricle healed without complications and was totally ablated. All horses had inspiratory stridor when exercised 14 weeks after laser irradiation.

  2. Power neodymium-glass amplifier of a repetitively pulsed laser

    NASA Astrophysics Data System (ADS)

    Vinogradov, Aleksandr V.; Gaganov, V. E.; Garanin, Sergey G.; Zhidkov, N. V.; Krotov, V. A.; Martynenko, S. P.; Pozdnyakov, E. V.; Solomatin, I. I.

    2011-11-01

    A neodymium-glass diode-pumped amplifier with a zigzag laser beam propagation through the active medium was elaborated; the amplifier is intended for operation in a repetitively pulsed laser. An amplifier unit with an aperture of 20 × 25 mm and a ~40-cm long active medium was put to a test. The energy of pump radiation amounts to 140 J at a wavelength of 806 nm for a pump duration of 550 μs. The energy parameters of the amplifier were experimentally determined: the small-signal gain per pass ~3.2, the linear gain ~0.031 cm-1 with a nonuniformity of its distribution over the aperture within 15%, the stored energy of 0.16 — 0.21 J cm-3. The wavefront distortions in the zigzag laser-beam propagation through the active element of the amplifier did not exceed 0.4λ (λ = 0.63 μm is the probing radiation wavelength).

  3. Phase equilibria in the neodymium-cadmium binary system.

    PubMed

    Skołyszewska-Kühberger, Barbara; Reichmann, Thomas L; Ipser, Herbert

    2014-09-05

    The equilibrium phase diagram of the neodymium-cadmium system has been established by thermal, metallographic and X-ray analysis based on a study of 70 alloys. The system contains three congruently melting intermetallic compounds, i.e. NdCd (1040 °C), NdCd2 (995 °C), Nd11Cd45 (855 °C), and four incongruently melting compounds NdCd3 (860 °C), Nd13Cd58 (740 °C), NdCd6 (655 °C) and NdCd11 (520 °C). Four eutectic reactions are found in this binary system, i.e. at ∼25 at.% Cd and 770 °C, at 58 at.% Cd and 955 °C, at 79 at.% Cd and 850 °C, and very close to pure Cd at 318 °C, as well as one eutectoid reaction at ∼15 at.% Cd and 500 °C. The solid solubility of Nd in Cd is negligible. Dilatometric curves were recorded for three Nd-Cd compositions up to 4 at.% Cd, to accurately determine phase transitions between the solid solutions of Cd in the low- and high-temperature modification of Nd.

  4. Laboratory and clinical experience with neodymium:YAG laser prostatectomy

    NASA Astrophysics Data System (ADS)

    Kabalin, John N.

    1996-05-01

    Since 1991, we have undertaken extensive laboratory and clinical studies of the Neodymium:YAG (Nd:YAG) laser for surgical treatment of bladder outlet obstruction due to prostatic enlargement or benign prostatic hyperplasia (BPH). Side-firing optical fibers which emit a divergent, relatively low energy density Nd:YAG laser beam produce coagulation necrosis of obstructing periurethral prostate tissue, followed by gradual dissolution and slough in the urinary stream. Laser-tissue interactions and Nd:YAG laser dosimetry for prostatectomy have been studied in canine and human prostate model systems, enhancing clinical application. Ongoing studies examine comparative Nd:YAG laser dosimetry for various beam configurations produced by available side-firing optical fibers and continue to refine operative technique. We have documented clinical outcomes of Nd:YAG laser prostatectomy in 230 consecutive patients treated with the UrolaseTM side-firing optical fiber. Nd:YAG laser coagulation the prostate produces a remarkably low acute morbidity profile, with no significant bleeding or fluid absorption. No postoperative incontinence has been produced. Serial assessments of voiding outcomes over more than 3 years of followup show objective and symptomatic improvement following Nd:YAG laser prostatectomy which is comparable to older but more morbid electrosurgical approaches. Nd:YAG laser prostatectomy is a safe, efficacious, durable and cost-effective treatment for BPH.

  5. Dielectric and impedance behavior of neodymium substituted strontium hexaferrite

    NASA Astrophysics Data System (ADS)

    Bhat, Bilal Hamid; Samad, Rubiya; Want, Basharat

    2016-09-01

    In this study, dielectric behavior and complex impedance of neodymium (Nd) substituted strontium hexaferrite system: Sr1- x Nd x Fe12O19 ( x = 0.0, 0.05, 0.1, 0.15, 0. 20), synthesized by citrate precursor technique, have been evaluated as a function of applied frequency and temperature. Variation of dielectric constant and dielectric loss with frequency shows the identical behavior for all the compositions. The value of dielectric constant increases with Nd doping. Relaxation process is observed in the composition x = 0.20, and the peaks in this composition shift toward the higher-frequency region as the temperature increases. The dielectric constants show temperature-independent behavior at low temperature, whereas at higher temperatures it increases for all the frequencies. The AC conductivity follows Jonscher's power law, showing that conduction mechanism is due to polaron hopping. Complex impedance as a function of composition and temperature is used to examine the role of grain and grain boundary in the prepared material. Cole-cole plot shows only one semicircle up to x = 0.15, while as for x = 0.20 two semicircles are observed. The conduction mechanism is explained on the basis of both grain and grain boundary.

  6. Lightweight Beryllium Free Nanostructured Nanostructured Composites

    DTIC Science & Technology

    2007-11-02

    Plasma Processes, Inc. Lightweight Beryllium Free Nanostructured Composites SBIR Contract DASG60-02-P-41 Phase I Final Report 1/15/03 Submitted by...Report Type N/A Dates Covered (from... to) - Title and Subtitle Lightweight Beryllium Free Nanostructured Nanostructured Composites Contract

  7. Titanium Nitride Cermets

    DTIC Science & Technology

    1952-07-01

    7696i ’-Brewer, L., et al. Thermodynamic and Physical Properties of Nitrides. Carbides, Sulfides, i1licides, and Phosphides, Chemistry and Metallurgy of...12 Referen eCs 0 . ...................... • • • 14 WADC TR 52-155 iv LIST OF TABLES I Properties of Titanium Nitride Bodies...15 II Properties of Titanium Nitride-Nickel Bodies............16 III Properties of Titanium Nitride Cermets with Nickel,..... 17 Cobalt, and

  8. Electrolytic production of neodymium without perfluorinated carbon compounds on the offgases

    DOEpatents

    Keller, R.; Larimer, K.T.

    1998-09-22

    A method is described for producing neodymium in an electrolytic cell without formation of perfluorinated carbon gases (PFCs), the method comprising the steps of providing an electrolyte in the electrolytic cell and providing an anode in an anode region of the electrolyte and providing a cathode in a cathode region of the electrolytic cell. Dissolving an oxygen-containing neodymium compound in the electrolyte in the anode region and maintaining a more intense electrolyte circulation in the anode region than in the cathode region. Passing an electrolytic current between said anode and said cathode and depositing neodymium metal at the cathode, preventing the formation of perfluorinated carbon gases by limiting anode over voltage. 4 figs.

  9. Biomimetic helical rosette nanotubes and nanocrystalline hydroxyapatite coatings on titanium for improving orthopedic implants.

    PubMed

    Zhang, Lijie; Chen, Yupeng; Rodriguez, Jose; Fenniri, Hicham; Webster, Thomas J

    2008-01-01

    Natural bone consists of hard nanostructured hydroxyapatite (HA) in a nanostructured protein-based soft hydrogel template (ie, mostly collagen). For this reason, nanostructured HA has been an intriguing coating material on traditionally used titanium for improving orthopedic applications. In addition, helical rosette nanotubes (HRNs), newly developed materials which form through the self-assembly process of DNA base pair building blocks in body solutions, are soft nanotubes with a helical architecture that mimics natural collagen. Thus, the objective of this in vitro study was for the first time to combine the promising attributes of HRNs and nanocrystalline HA on titanium and assess osteoblast (bone-forming cell) functions. Different sizes of nanocrystalline HA were synthesized in this study through a wet chemical precipitation process following either hydrothermal treatment or sintering. Transmission electron microscopy images showed that HRNs aligned with nanocrystalline HA, which indicates a high affinity between both components. Some of the nanocrystalline HA formed dense coatings with HRNs on titanium. More importantly, results demonstrated enhanced osteoblast adhesion on the HRN/nanocrystalline HA-coated titanium compared with conventional uncoated titanium. Among all the HRN/nanocrystalline HA coatings tested, osteoblast adhesion was the greatest when HA nanometer particle size was the smallest. In this manner, this study demonstrated for the first time that biomimetic HRN/nanocrystalline HA coatings on titanium were cytocompatible for osteoblasts and, thus, should be further studied for improving orthopedic implants.

  10. Rare earth elements and neodymium isotopes in sedimentary organic matter

    NASA Astrophysics Data System (ADS)

    Freslon, Nicolas; Bayon, Germain; Toucanne, Samuel; Bermell, Sylvain; Bollinger, Claire; Chéron, Sandrine; Etoubleau, Joel; Germain, Yoan; Khripounoff, Alexis; Ponzevera, Emmanuel; Rouget, Marie-Laure

    2014-09-01

    We report rare earth element (REE) and neodymium (Nd) isotope data for the organic fraction of sediments collected from various depositional environments, i.e. rivers (n = 25), estuaries (n = 18), open-ocean settings (n = 15), and cold seeps (n = 12). Sedimentary organic matter (SOM) was extracted using a mixed hydrogen peroxide/nitric acid solution (20%-H2O2-0.02 M-HNO3), after removal of carbonate and oxy-hydroxide phases with dilute hydrochloric acid (0.25 M-HCl). A series of experimental tests indicate that extraction of sedimentary organic compounds using H2O2 may be complicated occasionally by partial dissolution of sulphide minerals and residual carbonates. However, this contamination is expected to be minor for REE because measured concentrations in H2O2 leachates are about two-orders of magnitude higher than in the above mentioned phases. The mean REE concentrations determined in the H2O2 leachates for samples from rivers, estuaries, coastal seas and open-ocean settings yield relatively similar levels, with ΣREE = 109 ± 86 ppm (mean ± s; n = 58). The organic fractions leached from cold seep sediments display even higher concentration levels (285 ± 150 ppm; mean ± s; n = 12). The H2O2 leachates for most sediments exhibit remarkably similar shale-normalized REE patterns, all characterized by a mid-REE enrichment compared to the other REE. This suggests that the distribution of REE in leached sedimentary organic phases is controlled primarily by biogeochemical processes, rather than by the composition of the source from which they derive (e.g. pore, river or sea-water). The Nd isotopic compositions for organic phases leached from river sediments are very similar to those for the corresponding detrital fractions. In contrast, the SOM extracted from marine sediments display εNd values that typically range between the εNd signatures for terrestrial organic matter (inferred from the analysis of the sedimentary detrital fractions) and marine organic matter

  11. Recent Progress in the Development of Neodymium Doped Ceramic Yttria

    NASA Technical Reports Server (NTRS)

    Prasad, Narasimha S.; Edwards, Chris; Trivedi, Sudhir B.; Kutcher, Susan; Wang, Chen-Chia; Kim, Joo-Soo; Hommerich, Uwe; Shukla, Vijay; Sadangi, Rajendra; Kear, Bernard

    2007-01-01

    Solid-state lasers play a significant role in providing the technology necessary for active remote sensing of the atmosphere. Neodymium doped yttria (Nd:Y2O3) is considered to be an attractive material due to its possible lasing wavelengths of aprrox.914 nm and approx.946 nm for ozone profiling. These wavelengths when frequency tripled can generate UV light at approx.305 nm and approx.315 nm, which is particularly useful for ozone sensing using differential absorption lidar technique. For practical realization of space based UV transmitter technology, ceramic Nd:Y2O3 material is considered to possess great potential. A plasma melting and quenching method has been developed to produce Nd3+ doped powders for consolidation into Nd:Y2O3 ceramic laser materials. This far-from-equilibrium processing methodology allows higher levels of rare earth doping than can be achieved by equilibrium methods. The method comprises of two main steps: (a) plasma melting and quenching to generate dense, and homogeneous doped metastable powders, (b) pressure assisted consolidation of these powders by hot isostatic pressing to make dense nanocomposite ceramics. Using this process, several 1" x 1" ceramic cylinders have been produced. The infrared transmission of undoped Y2O3 ceramics was as high as approx.75% without anti-reflection coating. In the case of Nd:Y2O3 ceramics infrared transmission values of approx.50% were achieved. Furthermore, Nd:Y2O3 samples with dopant concentrations of up to approx.2 at. % were prepared without significant emission quenching.

  12. Preparation of yttrium, lanthanum, cerium, and neodymium basic carbonate particles by homogeneous precipitation

    SciTech Connect

    Akinc, M.; Sordelet, D. )

    1987-07-01

    Uniform yttrium, lanthanum, cerium, and neodymium basic carbonate particles were prepared by homogeneous precipitation. Powders were characterized with respect to size, shape, crystal structure, and thermal decomposition behavior. Yttria precursor particles were spherical, monosized (0.4 {mu}m), and amorphous; whereas lanthana, neodymia, and ceria precursors were prismatic (ranging from 1 to 6 {mu}m in size) and crystalline. Crystal structure was found to be ancylite-type orthorhombic symmetry in all three cases. Upon heating in air, yttrium, lanthanum, and neodymium precursors underwent two-step decomposition to first form oxycarbonate and then oxide. Cerium hydroxycarbonate decomposed in a single step to form the oxide.

  13. Synthesis of neodymium hydroxide nanotubes and nanorods by soft chemical process.

    PubMed

    Shi, Weidong; Yu, Jiangbo; Wang, Haishui; Yang, Jianhui; Zhang, Hongjie

    2006-08-01

    A facile soft chemical approach using cetyltrimethylammonium bromide (CTAB) as template is successfully designed for synthesis of neodymium hydroxide nanotubes. These nanotubes have an average outer diameter around 20 nm, inner diameter around 2 nm, and length ranging from 100 to 120 nm, high BET surface area of 495.71 m(2) g(-1). We also find that neodymium hydroxide nanorods would be obtained when CTAB absented in reaction system. The Nd(OH)3 nanorods might act as precursors that are converted into Nd2O3 nanorods through dehydration at 550 degrees C. The nanorods could exhibit upconversion emission characteristic under excitation of 591 nm at room temperature.

  14. Samarium-neodymium systematics in kimberlites and in the minerals of garnet lherzolite inclusions

    USGS Publications Warehouse

    Basu, A.R.; Tatsumoto, M.

    1979-01-01

    The initial ratios of neodymium-143 to neodymium-144 in kimberlites ranging in age between 90 ?? 106 to 1300 ?? 106 years from South Africa, India, and the United States are different from the corresponding ratios in the minerals of peridotite inclusions in the kimberlites but are identical to the ratios in the basaltic achondrite Juvinas at the times of emplacement of the respective kimberlite pipes. This correlation between the kimberlites and Juvinas, which represents the bulk chondritic earth in rare-earth elements, strongly indicates that the kimberlite's source in the mantle is chondritic in rare-earth elements and relatively primeval in composition. Copyright ?? 1979 AAAS.

  15. Samarium-neodymium systematics in kimberlites and in the minerals of garnet lherzolite inclusions.

    PubMed

    Basu, A R; Tatsumoto, M

    1979-07-27

    The initial ratios of neodymium-143 to neodymium-144 in kimberlites ranging in age between 90 x 10(6) to 1300 x 10(6) years from South Africa, India, and the United States are different from the corresponding ratios in the minerals of peridotite inclusions in the kimberlites but are identical to the ratios in the basaltic achondrite Juvinas at the times of emplacement of the respective kimberlite pipes. This correlation between the kimberlites and Juvinas, which represents the bulk chondritic earth in rare-earth elements, strongly indicates that the kimberlite's source in the mantle is chondritic in rare-earth elements and relatively primeval in composition.

  16. Nanostructured Coatings

    NASA Astrophysics Data System (ADS)

    Rivière, J.-P.

    In many branches of technology where surfaces are playing a growing role, the use of coatings is often the only way to provide surfaces with specific functional properties. For example, the austenitic stainless steels or titanium alloys exhibit poor resistance to wear and low hardness values, which limits the field of applications. The idea then is to develop new solutions which would improve the mechanical performance and durability of objects used in contact and subjected to mechanical forces in hostile gaseous or liquid environments. Hard coatings are generally much sought after to enhance the resistance to wear and corrosion. They are of particular importance because they constitute a class of protective coatings which is already widely used on an industrial scale to improve the hardness and lifetime of cutting tools.

  17. DNA nanostructure meets nanofabrication.

    PubMed

    Zhang, Guomei; Surwade, Sumedh P; Zhou, Feng; Liu, Haitao

    2013-04-07

    Recent advances in DNA nanotechnology have made it possible to construct DNA nanostructures of almost arbitrary shapes with 2-3 nm of precision in their dimensions. These DNA nanostructures are ideal templates for bottom-up nanofabrication. This review highlights the challenges and recent advances in three areas that are directly related to DNA-based nanofabrication: (1) fabrication of large scale DNA nanostructures; (2) pattern transfer from DNA nanostructure to an inorganic substrate; and (3) directed assembly of DNA nanostructures.

  18. Jumplike microdeformation of nanostructured metals

    NASA Astrophysics Data System (ADS)

    Peschanskaya, N. N.; Smirnov, B. I.; Shpeĭzman, V. V.

    2008-05-01

    The parameters of microdeformation jumps for copper, aluminum, titanium, and Armco iron with the initial (annealed) structure and after equal-channel angular pressing are investigated in a creep mode under low compressive stresses. The strain rate is measured with a laser interferometer in 0.15-μm linear displacements. It is demonstrated that the values of the microstrain rate and the mean sizes of jumps for the annealed metals are larger than those for the metals subjected to severe deformation. It is revealed that there is a correlation between the jumps of microplastic deformation and the size of nanometal grains. The inference is made that, for nanostructured metals, as for other materials, the structural heterogeneity is one of the factors responsible for the jumplike deformation.

  19. Sealing glasses for titanium and titanium alloys

    DOEpatents

    Brow, Richard K.; McCollister, Howard L.; Phifer, Carol C.; Day, Delbert E.

    1997-01-01

    Barium lanthanoborate sealing-glass compositions are provided comprising various combinations (in terms of mole-%) of boron oxide (B.sub.2 O.sub.3), barium oxide (BaO), lanthanum oxide (La.sub.2 O.sub.3), and at least one other oxide selected from the group consisting of aluminum oxide (Al.sub.2 O.sub.3), calcium oxide (CaO), lithium oxide (Li.sub.2 O), sodium oxide (Na.sub.2 O), silicon dioxide (SiO.sub.2), or titanium dioxide (TiO.sub.2). These sealing-glass compositions are useful for forming hermetic glass-to-metal seals with titanium and titanium alloys having an improved aqueous durability and favorable sealing characteristics. Examples of the sealing-glass compositions are provided having coefficients of thermal expansion about that of titanium or titanium alloys, and with sealing temperatures less than about 900.degree. C., and generally about 700.degree.-800.degree. C. The barium lanthanoborate sealing-glass compositions are useful for components and devices requiring prolonged exposure to moisture or water, and for implanted biomedical devices (e.g. batteries, pacemakers, defibrillators, pumps).

  20. Sealing glasses for titanium and titanium alloys

    DOEpatents

    Brow, R.K.; McCollister, H.L.; Phifer, C.C.; Day, D.E.

    1997-07-15

    Barium lanthanoborate sealing-glass compositions are provided comprising various combinations (in terms of mole-%) of boron oxide (B{sub 2}O{sub 3}), barium oxide (BaO), lanthanum oxide (La{sub 2}O{sub 3}), and at least one other oxide selected from the group consisting of aluminum oxide (Al{sub 2}O{sub 3}), calcium oxide (CaO), lithium oxide (Li{sub 2}O), sodium oxide (Na{sub 2}O), silicon dioxide (SiO{sub 2}), or titanium dioxide (TiO{sub 2}). These sealing-glass compositions are useful for forming hermetic glass-to-metal seals with titanium and titanium alloys having an improved aqueous durability and favorable sealing characteristics. Examples of the sealing-glass compositions are provided having coefficients of thermal expansion about that of titanium or titanium alloys, and with sealing temperatures less than about 900 C, and generally about 700--800 C. The barium lanthanoborate sealing-glass compositions are useful for components and devices requiring prolonged exposure to moisture or water, and for implanted biomedical devices (e.g. batteries, pacemakers, defibrillators, pumps). 1 fig.

  1. Sprayable titanium composition

    DOEpatents

    Tracy, Chester E.; Kern, Werner; Vibronek, Robert D.

    1980-01-01

    The addition of 2-ethyl-1-hexanol to an organometallic titanium compound dissolved in a diluent and optionally containing a lower aliphatic alcohol spreading modifier, produces a solution that can be sprayed onto a substrate and cured to form an antireflection titanium oxide coating having a refractive index of from about 2.0 to 2.2.

  2. Titanium and titanium alloys as dental materials.

    PubMed

    Lautenschlager, E P; Monaghan, P

    1993-06-01

    Because of light weight, high strength to weight ratio, low modulus of elasticity, and excellent corrosion resistance, titanium and some of its alloys have been important materials for the aerospace industry since the 1950s. Now, with the additional advantages of excellent biocompatibility, good local spot weldability, and easy shaping and finishing by a number of mechanical and electrochemical processes, these materials are finding uses in dental applications, such as implants and restorative castings. Although more research is still needed in areas such as development of optimal casting investments, porcelain veneering systems, device designs, and controlled biological responses, the present and future uses of titanium appear bright for dentistry.

  3. Enhanced human bone marrow mesenchymal stem cell functions on cathodic arc plasma-treated titanium.

    PubMed

    Zhu, Wei; Teel, George; O'Brien, Christopher M; Zhuang, Taisen; Keidar, Michael; Zhang, Lijie Grace

    2015-01-01

    Surface modification of titanium for use in orthopedics has been explored for years; however, an ideal method of integrating titanium with native bone is still required to this day. Since human bone cells directly interact with nanostructured extracellular matrices, one of the most promising methods of improving titanium's osseointegration involves inducing bio-mimetic nanotopography to enhance cell-implant interaction. In this regard, we explored an approach to functionalize the surface of titanium by depositing a thin film of textured titanium nanoparticles via a cathodic arc discharge plasma. The aim is to improve human bone marrow mesenchymal stem cell (MSC) attachment and differentiation and to reduce deleterious effects of more complex surface modification methods. Surface functionalization was analyzed by scanning electron microscopy, atomic force microscopy, contact angle testing, and specific protein adsorption. Scanning electron microscopy and atomic force microscopy examination demonstrate the deposition of titanium nanoparticles and the surface roughness change after coating. The specific fibronectin adsorption was enhanced on the modified titanium surface that associates with the improved hydrophilicity. MSC adhesion and proliferation were significantly promoted on the nanocoated surface. More importantly, compared to bare titanium, greater production of total protein, deposition of calcium mineral, and synthesis of alkaline phosphatase were observed from MSCs on nanocoated titanium after 21 days. The method described herein presents a promising alternative method for inducing more cell favorable nanosurface for improved orthopedic applications.

  4. Neodymium-rich precipitate phases in a high-chromium ferritic/martensitic steel

    NASA Astrophysics Data System (ADS)

    Shen, Yinzhong; Zhou, Xiaoling; Shang, Zhongxia

    2016-05-01

    Neodymium being considered as nitride forming element has been used in a design of advanced ferritic/martensitic (FM) steels for fossil fired power plants at service temperatures of 630 °C to 650 °C to effectively improve the creep strength of the steels. To fully understand the characteristics of neodymium precipitates in high-Cr FM steels, precipitate phases in an 11Cr FM steel with 0.03 wt% addition of Nd have been investigated by transmission electron microscopy. Three neodymium phases with a face-centered cubic crystal structure and different composition were observed in the steel. They consisted of neodymium carbonitride with an average lattice parameter of 1.0836 nm, Nd-rich carbonitride mainly containing Mn, and Nd-rich MN nitride mainly containing Mn and Co. Other three Nd-rich and Nd-containing phases, which appear to be Nd-Co-Cr/Nd-rich intermetallic compounds and Cr-Fe-rich nitride containing Nd, were also detected in the steel. Nd-relevant precipitates were found to be minor phases compared with M23C6 and Nb/V/Ta-rich MX phases in the steel. The content of Nd in other precipitate phases was very low. Most of added Nd is considered to be present as solid solution in the matrix of the steel.

  5. Demonstrating and Measuring Relative Molar Magnetic Susceptibility Using a Neodymium Magnet

    ERIC Educational Resources Information Center

    Malerich, Charles; Ruff, Patricia K.; Bird, Aubrey

    2004-01-01

    An easy-to-see method for demonstrating and measuring the magnetic force between paramagnetic substance and a rare earth magnet is presented. The readily available trapezoid-shaped neodymium magnet and a low cost, easy-to-set-up, portable apparatus are used in the experiments.

  6. Neodymium as the main feature of permanent magnets from hard disk drives (HDDs).

    PubMed

    München, Daniel Dotto; Veit, Hugo Marcelo

    2017-03-01

    As a way to manage neodymium-iron-boron (NdFeB) magnets wasted in end-of-life hard disk drives (HDDs), a waste characterization is needed prior to a recycling process. Due to their magnetic properties, NdFeB magnets are essential in technological applications nowadays, thus causing an increase in the industrial demand for rare earth metals. However, these metals have a short supply, since they are difficult to obtain from ores, creating a critical market. In this work, a study of the characterization of sintered neodymium-iron-boron magnets was undertaken by qualitatively and quantitatively uncovering the neodymium recovery potential from this type of electronic waste. From the collection and disassembly of hard disk drives, in which the magnet represents less than 3% of the total weight, an efficient demagnetization process was proceeded at 320°C. Then, the magnet was ground and screened for an X-ray diffraction (XRD) analysis, which showed the Nd2Fe14B tetragonal phase as the dominant constituent of the sample. An analysis was also carried out in a scanning electron microscope (SEM) and an inductively coupled plasma optical emission spectrometer (ICP-OES), where the magnet composition showed 21.5wt% of neodymium and 65.1wt% of iron, among other chemicals. This Nd content is higher than the one found in Nd ores, enhancing the recyclability and the importance of waste management.

  7. Neodymium YAG lasers. Citations from the International Aerospace Abstracts data base

    NASA Technical Reports Server (NTRS)

    Mauk, S. C.

    1980-01-01

    Various aspects of neodymium yag lasers are discussed in approximately 267 citations. Laser materials and outputs, laser mode locking; crystal, fiber, and nonlinear optics, optical pumping communications, energy conversion efficiency, and laser applications are covered. Pulsed, continuous wave, solid state, Q switched, infrared, and dye lasers are included.

  8. Neodymium and hafnium boundary contributions to seawater along the West Antarctic continental margin

    NASA Astrophysics Data System (ADS)

    Rickli, Jörg; Gutjahr, Marcus; Vance, Derek; Fischer-Gödde, Mario; Hillenbrand, Claus-Dieter; Kuhn, Gerhard

    2014-05-01

    Neodymium and hafnium isotopes and elemental concentrations (Sm, Nd, Hf, Zr) have been measured in three water column profiles south of the Antarctic Circumpolar Current in, and to the east of the Ross Sea, in conjunction with five bottom water samples from the Amundsen Sea Embayment.

  9. Neodymium YAG (yttrium-aluminum-garnet) lasers. (Latest citations from the Inspec database). Published Search

    SciTech Connect

    1996-02-01

    The bibliography contains citations concerning the properties and applications of neodymium-yttrium-aluminum-garnet (Nd:YAG) lasers. Applications include welding, soldering of printed circuit boards, medical applications, telecommunication systems, rangefinding, and optical pumping of high powered lasers.(Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  10. Nanostructured metal foams: synthesis and applications

    SciTech Connect

    Luther, Erik P; Tappan, Bryce; Mueller, Alex; Mihaila, Bogdan; Volz, Heather; Cardenas, Andreas; Papin, Pallas; Veauthier, Jackie; Stan, Marius

    2009-01-01

    Fabrication of monolithic metallic nanoporous materials is difficult using conventional methodology. Here they report a relatively simple method of synthesizing monolithic, ultralow density, nanostructured metal foams utilizing self-propagating combustion synthesis of novel metal complexes containing high nitrogen energetic ligands. Nanostructured metal foams are formed in a post flame-front dynamic assembly with densities as low as 0.011 g/cc and surface areas as high as 270 m{sup 2}/g. They have produced metal foams via this method of titanium, iron, cobalt, nickel, zirconium, copper, palladium, silver, hafnium, platinum and gold. Microstructural features vary as a function of composition and process parameters. Applications for the metal foams are discussed including hydrogen absorption in palladium foams. A model for the sorption kinetics of hydrogen in the foams is presented.

  11. Mechanisms of magma generation beneath hawaii and mid-ocean ridges: uranium/thorium and samarium/neodymium isotopic evidence.

    PubMed

    Sims, K W; Depaolo, D J; Murrell, M T; Baldridge, W S; Goldstein, S J; Clague, D A

    1995-01-27

    Measurements of uranium/thorium and samarium/neodymium isotopes and concentrations in a suite of Hawaiian basalts show that uranium/thorium fractionation varies systematically with samarium/neodymium fractionation and major-element composition; these correlations can be understood in terms of simple batch melting models with a garnet-bearing peridotite magma source and melt fractions of 0.25 to 6.5 percent. Midocean ridge basalts shows a systematic but much different relation between uranium/thorium fractionation and samarium/neodymium fractionation, which, although broadly consistent with melting of a garnet-bearing peridotite source, requires a more complex melting model.

  12. Velocity measurements of inert porous materials driven by infrared-laser-ablated thin-film titanium

    SciTech Connect

    Bedeaux, Brett C.; Trott, Wayne M.; Castaneda, Jaime N.

    2010-02-15

    This article presents and interprets a series of experiments performed to measure the velocity of four inert low-density porous materials that were accelerated by an ablated thin-film titanium metal, created by vaporizing a 250-nm-thick layer of titanium with a high-energy, Q-switched, pulsed, and 1.054 {mu}m neodymium-glass laser. Inert powder materials were chosen to match, among other characteristics, the morphology of energetic materials under consideration for use in detonator applications. The observed behavior occurs near the thin-film titanium ablation layer, through complex physical mechanisms, including laser absorption in the metal layer, ablation and formation of confined plasma that is a blackbody absorber of the remaining photon energy, and vaporization of the remaining titanium metal. One-dimensional hydrodynamic modeling provided a basis of comparison with the measured velocities. We found, as predicted in wave-propagation-code modeling, that an Asay foil can indicate total momentum of the driven material that is mechanically softer (lower in shock impedance) than the foil. The key conclusion is that the specific impulse delivered by the laser transfers a corresponding momentum to soft, organic power columns that are readily compacted. Impulse from the laser is less efficient in transferring momentum to hard inorganic particles that are less readily compacted.

  13. Electroplating on titanium alloy

    NASA Technical Reports Server (NTRS)

    Lowery, J. R.

    1971-01-01

    Activation process forms adherent electrodeposits of copper, nickel, and chromium on titanium alloy. Good adhesion of electroplated deposits is obtained by using acetic-hydrofluoric acid anodic activation process.

  14. Preparation of transparent neodymium-doped yttrium aluminate garnet (Nd:YAG) ceramics with the use of freeze granulation

    NASA Astrophysics Data System (ADS)

    Wajler, Anna; Węglarz, Helena; Sidorowicz, Agata; Zych, Łukasz; Nakielska, Magdalena; Jach, Katarzyna; Tomaszewski, Henryk

    2015-12-01

    This paper presents the results of the application of freeze granulation to the production of transparent neodymium-doped yttrium-aluminum garnet ceramics. Aqueous suspensions of aluminium oxide, yttrium oxide and neodymium oxide powders were prepared based on nanometric or submicronic powders which were either commercially available or prepared by precipitation. The relations between the composition of suspension, the properties of granulate and the final properties of ceramics (microstructure, optical transmission and emission spectra) were studied.

  15. Titanium by design: TRIP titanium alloy

    NASA Astrophysics Data System (ADS)

    Tran, Jamie

    Motivated by the prospect of lower cost Ti production processes, new directions in Ti alloy design were explored for naval and automotive applications. Building on the experience of the Steel Research Group at Northwestern University, an analogous design process was taken with titanium. As a new project, essential kinetic databases and models were developed for the design process and used to create a prototype design. Diffusion kinetic models were developed to predict the change in phase compositions and microstructure during heat treatment. Combining a mobility database created in this research with a licensed thermodynamic database, ThermoCalc and DICTRA software was used to model kinetic compositional changes in titanium alloys. Experimental diffusion couples were created and compared to DICTRA simulations to refine mobility parameters in the titanium mobility database. The software and database were able to predict homogenization times and the beta→alpha plate thickening kinetics during cooling in the near-alpha Ti5111 alloy. The results of these models were compared to LEAP microanalysis and found to be in reasonable agreement. Powder metallurgy was explored using SPS at GM R&D to reduce the cost of titanium alloys. Fully dense Ti5111 alloys were produced and achieved similar microstructures to wrought Ti5111. High levels of oxygen in these alloys increased the strength while reducing the ductility. Preliminary Ti5111+Y alloys were created, where yttrium additions successfully gettered excess oxygen to create oxides. However, undesirable large oxides formed, indicating more research is needed into the homogeneous distribution of the yttrium powder to create finer oxides. Principles established in steels were used to optimize the beta phase transformation stability for martensite transformation toughening in titanium alloys. The Olson-Cohen kinetic model is calibrated to shear strains in titanium. A frictional work database is established for common alloying

  16. Enhanced human bone marrow mesenchymal stem cell functions on cathodic arc plasma-treated titanium

    PubMed Central

    Zhu, Wei; Teel, George; O’Brien, Christopher M; Zhuang, Taisen; Keidar, Michael; Zhang, Lijie Grace

    2015-01-01

    Surface modification of titanium for use in orthopedics has been explored for years; however, an ideal method of integrating titanium with native bone is still required to this day. Since human bone cells directly interact with nanostructured extracellular matrices, one of the most promising methods of improving titanium’s osseointegration involves inducing bio-mimetic nanotopography to enhance cell–implant interaction. In this regard, we explored an approach to functionalize the surface of titanium by depositing a thin film of textured titanium nanoparticles via a cathodic arc discharge plasma. The aim is to improve human bone marrow mesenchymal stem cell (MSC) attachment and differentiation and to reduce deleterious effects of more complex surface modification methods. Surface functionalization was analyzed by scanning electron microscopy, atomic force microscopy, contact angle testing, and specific protein adsorption. Scanning electron microscopy and atomic force microscopy examination demonstrate the deposition of titanium nanoparticles and the surface roughness change after coating. The specific fibronectin adsorption was enhanced on the modified titanium surface that associates with the improved hydrophilicity. MSC adhesion and proliferation were significantly promoted on the nanocoated surface. More importantly, compared to bare titanium, greater production of total protein, deposition of calcium mineral, and synthesis of alkaline phosphatase were observed from MSCs on nanocoated titanium after 21 days. The method described herein presents a promising alternative method for inducing more cell favorable nanosurface for improved orthopedic applications. PMID:26677327

  17. NEW ACTIVE MEDIA AND ELEMENTS OF LASER SYSTEMS: Influence of short-lived color centers on the lifetime of a metastable level of neodymium in silicate glasses

    NASA Astrophysics Data System (ADS)

    Dzhibladze, M. I.; Lazarev, L. E.

    1987-11-01

    It was found that the short-lived color centers formed in neodymium-activated silicate glasses under the action of the violet part of the pump spectrum increased the lifetime of a neodymium metastable level by more than an order of magnitude in needle-shaped waveguide lasers. The highly efficient suppression of superradiance and a strong increase in the gain of the active element were due to stimulated decay of the color centers accompanying absorption of photons emitted by the neodymium.

  18. Solar nebula heterogeneity in p-process samarium and neodymium isotopes.

    PubMed

    Andreasen, Rasmus; Sharma, Mukul

    2006-11-03

    Bulk carbonaceous chondrites display a deficit of approximately 100 parts per million (ppm) in 144Sm with respect to other meteorites and terrestrial standards, leading to a decrease in their 142Nd/144Nd ratios by approximately 11 ppm. The data require that samarium and neodymium isotopes produced by the p process associated with photodisintegration reactions in supernovae were heterogeneously distributed in the solar nebula. Other samarium and neodymium isotopes produced by rapid neutron capture (r process) in supernovae and by slow neutron capture (s process) in red giants were homogeneously distributed. The supernovae sources supplying the p- and r-process nuclides to the solar nebula were thus disconnected or only weakly connected.

  19. Neodymium-doped nanoparticles for infrared fluorescence bioimaging: The role of the host

    SciTech Connect

    Rosal, Blanca del; Pérez-Delgado, Alberto; Rocha, Ueslen; Martín Rodríguez, Emma; Jaque, Daniel; Misiak, Małgorzata; Bednarkiewicz, Artur; Vanetsev, Alexander S.; Orlovskii, Yurii; Jovanović, Dragana J.; Dramićanin, Miroslav D.; Upendra Kumar, K.; Jacinto, Carlos; Navarro, Elizabeth; and others

    2015-10-14

    The spectroscopic properties of different infrared-emitting neodymium-doped nanoparticles (LaF{sub 3}:Nd{sup 3+}, SrF{sub 2}:Nd{sup 3+}, NaGdF{sub 4}: Nd{sup 3+}, NaYF{sub 4}: Nd{sup 3+}, KYF{sub 4}: Nd{sup 3+}, GdVO{sub 4}: Nd{sup 3+}, and Nd:YAG) have been systematically analyzed. A comparison of the spectral shapes of both emission and absorption spectra is presented, from which the relevant role played by the host matrix is evidenced. The lack of a “universal” optimum system for infrared bioimaging is discussed, as the specific bioimaging application and the experimental setup for infrared imaging determine the neodymium-doped nanoparticle to be preferentially used in each case.

  20. Photocatalytic treatment of municipal wastewater using modified neodymium doped TiO(2) hybrid nanoparticles.

    PubMed

    Shahmoradi, Behzad; Ibrahim, Ibrahim A; Sakamoto, Naonori; Ananda, Sannaiah; Somashekar, Rudrappa; Row, Tagur N Guru; Byrappa, Kullaiah

    2010-08-01

    Photocatalytic degradation of municipal wastewater was investigated using reagent grade TiO(2) and modified neodymium doped TiO(2) hybrid nanoparticles. For the first time, surface modification of Nd(3 +) doped TiO(2) hybrid nanoparticles were carried out with n-butylamine as surface modifier under mild hydrothermal conditions. The modified nanoparticles obtained were characterized by Powder XRD, FTIR, DLS, TEM, BET surface area, zeta potential and UV-Vis Spectroscopy. The characterization results indicated better morphology, particle size distribution and low agglomeration of the nanoparticles synthesized. It was found that photodegradation of wastewater using surface modified neodymium doped TiO(2) nanoparticles was more compared to pure TiO(2), which can be attributed to the doping and modification with n-butylamine.

  1. Determination of some heavy metals by flame atomic absorption spectrometry before coprecipitation with neodymium hydroxide.

    PubMed

    Soylak, Mustafa; Kizil, Nebiye

    2011-01-01

    A procedure is described for the determination of trace amounts of Cd(II), Ni(II), Cu(II), Pb(II), Fe(III), Co(II), and Mn(II) that combines flame atomic absorption spectrometry with neodymium hydroxide coprecipitation. The influences of analytical parameters (amount of neodymium, pH of the model solutions, etc.) that affect quantitative recoveries of the analyte ions were investigated. The effects of concomitant ions were also examined. The detection limits for analytes were found in the range of 0.2-3.3 microg/L. The validation of the presented procedure was controlled by analysis of certified reference materials (National Institute of Standards and Technology 1570a spinach leaves and TMDA 54.4 fortified lake water). The applications of the procedure were performed by the analysis of water, food, and herbal plants from Turkey.

  2. Stabilization of neodymium oxide nanoparticles via soft adsorption of charged polymers.

    PubMed

    Dorris, Annie; Sicard, Clémence; Chen, Mark C; McDonald, Arthur B; Barrett, Christopher J

    2011-09-01

    In this work, two synthetic polyelectrolytes, PSS and PAH, are employed as strong adsorbed surfactants to disperse and stabilize neodymium oxide nanoparticles. The acid-base equilibria of the oxide surfaces of the particles were investigated under different pH conditions in the absence and presence of polyelectrolytes, to optimize particle stabilization through enhancement of the effective repulsive surface charges. Surface charge amplification of a 3:5 ratio was achieved to permit improved particle transparency of 100-fold in visible wavelengths in neutral and acidic pH regimes, and a stable 10-fold surface charge amplification was achieved under basic pH conditions. The potential of polyelectrolytes as stabilizing agents for neodymium oxide NPs in large-scale particle physics experiments requiring extremely high optical transparency over long path length is evaluated based on optical absorbance and particle stability.

  3. Lattice thermal expansion and solubility limits of neodymium-doped ceria

    NASA Astrophysics Data System (ADS)

    Zhang, Jinhua; Ke, Changming; Wu, Hongdan; Yu, Jishun; Wang, Jingran

    2016-11-01

    NdxCe1-xO2-0.5x (x=0-1.0) powders were prepared by reverse coprecipitation-calcination method and characterized by XRD. The crystal structure of product powders transformed from single fluorite structure to the complex of fluorite and C-type cubic structure, and finally to trigonal structure with the increase of x-value. An empirical equation simulating the lattice parameter of neodymium doped ceria was established based on the experimental data. The lattice parameters of the fluorite structure solid solutions increased with extensive adoption of Nd3+, and the heating temperature going up. The average thermal expansion coefficients of neodymium doped ceria with fluorite structure are higher than 13.5×10-6 °C-1 from room temperature to 1200 °C.

  4. Neodymium-doped nanoparticles for infrared fluorescence bioimaging: The role of the host

    NASA Astrophysics Data System (ADS)

    del Rosal, Blanca; Pérez-Delgado, Alberto; Misiak, Małgorzata; Bednarkiewicz, Artur; Vanetsev, Alexander S.; Orlovskii, Yurii; Jovanović, Dragana J.; Dramićanin, Miroslav D.; Rocha, Ueslen; Upendra Kumar, K.; Jacinto, Carlos; Navarro, Elizabeth; Martín Rodríguez, Emma; Pedroni, Marco; Speghini, Adolfo; Hirata, Gustavo A.; Martín, I. R.; Jaque, Daniel

    2015-10-01

    The spectroscopic properties of different infrared-emitting neodymium-doped nanoparticles (LaF3:Nd3+, SrF2:Nd3+, NaGdF4: Nd3+, NaYF4: Nd3+, KYF4: Nd3+, GdVO4: Nd3+, and Nd:YAG) have been systematically analyzed. A comparison of the spectral shapes of both emission and absorption spectra is presented, from which the relevant role played by the host matrix is evidenced. The lack of a "universal" optimum system for infrared bioimaging is discussed, as the specific bioimaging application and the experimental setup for infrared imaging determine the neodymium-doped nanoparticle to be preferentially used in each case.

  5. Development of a novel neodymium compound for in vivo fluorescence imaging.

    PubMed

    Aita, Kazuki; Temma, Takashi; Kuge, Yuji; Saji, Hideo

    2007-01-01

    We developed a novel fluorescent probe that contains the neodymium(III) complex moiety and fluorescein moiety. This probe can emit long-lived near-infrared luminescence derived from a Nd ion through excitation of the fluorescein moiety with visible light (lambda(ex) = 488 nm, lambda(em) = 880 nm, lifetime = 2.3 micros). These results indicate the possibility of the probe as a candidate for in vivo fluorescence molecular imaging.

  6. Neodymium(III) Complexation by Amino-Carbohydrates via a Ligand-Controlled Hydrolysis Mechanism

    SciTech Connect

    Levitskaia, Tatiana G.; Chen, Yongsheng; Fulton, John L.; Sinkov, Sergey I.

    2011-07-28

    Chelation of neodymium-III Nd(III) by D-glucosamine (DGA) and chitosan was investigated in solution at near-physiological pH and ionic strength. This research demonstrates the first example of the lanthanide ion heteroleptic hydroxo-carbohydrate complex in solution. It was demonstrated that DGA and chitosan suppressed formation of polynuclear Nd(III) species at elevated pH.

  7. Cuprate superconductors on titanium substrates

    NASA Astrophysics Data System (ADS)

    Mitterbauer, Christina; Gritzner, Gerhard

    2007-09-01

    The applicability of titanium as substrate material for coated conductors was investigated. Titanium metal was rolled to a thickness of 1 mm and mechanically polished. The titanium sheets were oxidized in air at 1000 °C for 1 h. A dense oxide layer was formed. YBCO superconducting layers were applied to the oxidized titanium surface via screen printing from a suspension in acetone-terpineol. The YBCO layers were characterized by X-ray diffraction and by scanning electron microscopy.

  8. X-ray radiometric determination of lanthanides (praseodymium, neodymium, and samarium) in soils

    NASA Astrophysics Data System (ADS)

    Savichev, A. T.; Vodyanitskii, Yu. N.

    2011-04-01

    A procedure of the modified energy-dispersive X-ray fluorescence method (X-ray radiometric analysis using a 241Am radionuclide source) was developed for the identification of praseodymium, neodymium, and samarium. The procedure is based on the exclusion of the disturbing effect of barium and lanthanum on the lines of praseodymium and neodymium, as well as the effect of lanthanum and cerium on the lines of samarium. On the basis of the new method, data were obtained on the geochemistry of three lanthanides in soils of the northern taiga. Praseodymium and neodymium were detected by the X-ray radiometric method even in podzols depleted of heavy metals. The method can detect samarium at the levels of the soil clarke and higher. Positive samarium (or, wider, rare-earth) anomalies can be expected in the soils located not far from the deposits of apatite-nephelines, loparites, and phosphorites and in the soils developed on alkaline granites and carbonate weathering crusts.

  9. Powerful neodymium laser radiation for the treatment of facial carcinoma: 5 year follow-up data.

    PubMed

    Moskalik, Konstantin; Kozlow, Alexander; Demin, Eugeny; Boiko, Ernest

    2010-01-01

    A retrospective non-comparative follow-up study was performed to evaluate the curative efficacy of powerful neodymium laser radiation (λ = 1,060 nm) for the treatment of 2,837 patients with 3,001 histologically confirmed facial skin carcinoma lesions of stages T1-2N0M0: 2,743 primary basal cell carcinomas (BCC), 172 recurrent limited basal cell carcinomas (RLBCC), and 86 primary squamous cells carcinomas (SCC). All patients were followed-up from 5 to 11 years (mean: 8.2 years; median: 7.0 years) after treatment. The overall recurrence rate (RR) after treatment with laser radiation of facial carcinomas was 2.5% of all irradiated tumours (mean: 13.4 months; median: 11.0 months). Patients with BCC treated by radiation with the pulsed Neodymium (Nd) laser developed RR in 2.2% of cases and patients treated with the Nd:YAG laser had RR of 3.1%. Recurrences following treatment for RLBCC, and those of SCC, after irradiation with the Nd laser appeared in 4.1% and 4.6% of patients, respectively. Neodymium laser radiation is a safe and effective means of treating facial carcinomas of stages T1-2N0M0 with good cosmetic results.

  10. Stability of the complexes of some lanthanides with coumarin derivatives. II. Neodymium(III)-acenocoumarol.

    PubMed

    Kostova, Irena; Manolov, Ilia; Radulova, Maritza

    2004-06-01

    A complex of neodymium(III) with 4-hydroxy-3[1-(4-nitrophenyl)-3-oxobutyl]-2H-1-benzopyran-2-one (acenocoumarol) was synthesized by mixing water solutions of neodymium(III) nitrate and the ligand (metal to ligand molar ratio of 1:3). The complex was characterized and identified by elemental analysis, conductivity, IR, 1H NMR and mass spectral data. DTA and TGA were applied to study the composition of the compound. Elemental and mass spectral analysis of the complex indicated the formation of a compound of the composition NdR3 x 6H2O, where R = C19H14NO6-) The reaction of neodymium(III) with acenocoumarol was studied in detail by the spectrophotometric method. The stepwise formation of three complexes, vis., NdR2+, NdR2+ and NdR3 was established in the pH region studied (pH 3.0-7.5). The equilibrium constants for 1:1, 1:2 and 1:3 complexes were determined to be log K1 = 6.20 +/- 0.06; log K2 = 3.46 +/- 0.07 and log K2) = 2.58 +/- 0.05, respectively.

  11. Subtissue thermal sensing based on neodymium-doped LaF₃ nanoparticles.

    PubMed

    Rocha, Uéslen; Jacinto da Silva, Carlos; Ferreira Silva, Wagner; Guedes, Ilde; Benayas, Antonio; Martínez Maestro, Laura; Acosta Elias, Mónica; Bovero, Enrico; van Veggel, Frank C J M; García Solé, José Antonio; Jaque, Daniel

    2013-02-26

    In this work, we report the multifunctional character of neodymium-doped LaF₃ core/shell nanoparticles. Because of the spectral overlap of the neodymium emission bands with the transparency windows of human tissues, these nanoparticles emerge as relevant subtissue optical probes. For neodymium contents optimizing the luminescence brightness of Nd³⁺:LaF₃ nanoparticles, subtissue penetration depths of several millimeters have been demonstrated. At the same time, it has been found that the infrared emission bands of Nd³⁺:LaF₃ nanoparticles show a remarkable thermal sensitivity, so that they can be advantageously used as luminescent nanothermometers for subtissue thermal sensing. This possibility has been demonstrated in this work: Nd³⁺:LaF₃ nanoparticles have been used to provide optical control over subtissue temperature in a single-beam plasmonic-mediated heating experiment. In this experiment, gold nanorods are used as nanoheaters while thermal reading is performed by the Nd³⁺:LaF₃ nanoparticles. The possibility of a real single-beam-controlled subtissue hyperthermia process is, therefore, pointed out.

  12. Separation of samarium and neodymium: a prerequisite for getting signals from nuclear synthesis.

    PubMed

    Maji, Samir; Lahiri, Susanta; Wierczinski, Birgit; Korschinek, Gunther

    2006-12-01

    (146)Sm (T(1/2) = 10(8) y) is a long-lived radionuclide which has been produced in significant amounts during burning in a supernova (SN). Detection of this SN produced long-lived radionuclide on Earth may be helpful for getting information on nuclear synthesis at the time of our solar system's formation. Only accelerator mass spectrometry (AMS) can determine such minute traces of (146)Sm still expected in the Earth's crust. However, the villain of (146)Sm measurement through AMS is its naturally occurring stable isobar (146)Nd which is a million times more abundant than the trace amount of (146)Sm. Therefore an efficient method for the separation of samarium and neodymium is required to measure (146)Sm through AMS. A simple liquid-liquid extraction (LLX) based method for separation of samarium and neodymium has been developed using radiometric simulation. Di-(2-ethylhexyl)phosphoric acid (HDEHP) has been used as the organic reagent. A very high separation factor ( approximately 10(6)) can be achieved when a solution containing samarium and neodymium is reduced by hydroxylamine hydrochloride followed by extraction with 0.1% HDEHP diluted in cyclohexane from 0.025 M HCl solution.

  13. Weld-bonded titanium structures

    NASA Technical Reports Server (NTRS)

    Vaughan, R. W.; Creedon, J. F. (Inventor)

    1976-01-01

    Structurally stronger titanium articles are produced by a weld-bonding technique comprising fastening at least two plates of titanium together using spotwelding and curing an adhesive interspersed between the spot-weld nuggets. This weld-bonding may be employed to form lap joints or to stiffen titanium metal plates.

  14. Mineral of the month: titanium

    USGS Publications Warehouse

    Gambogi, Joseph

    2004-01-01

    From paint to airplanes, titanium is important in a number of applications. Commercial production comes from titanium-bearing ilmenite, rutile and leucoxene (altered ilmenite). These minerals are used to produce titanium dioxide pigment, as well as an assortment of metal and chemical products.

  15. Titanium metal: extraction to application

    SciTech Connect

    Gambogi, Joseph; Gerdemann, Stephen J.

    2002-09-01

    In 1998, approximately 57,000 tons of titanium metal was consumed in the form of mill products (1). Only about 5% of the 4 million tons of titanium minerals consumed each year is used to produce titanium metal, with the remainder primarily used to produce titanium dioxide pigment. Titanium metal production is primarily based on the direct chlorination of rutile to produce titanium tetrachloride, which is then reduced to metal using the Kroll magnesium reduction process. The use of titanium is tied to its high strength-to-weight ratio and corrosion resistance. Aerospace is the largest application for titanium. In this paper, we discuss all aspects of the titanium industry from ore deposits through extraction to present and future applications. The methods of both primary (mining of ore, extraction, and purification) and secondary (forming and machining) operations will be analyzed. The chemical and physical properties of titanium metal will be briefly examined. Present and future applications for titanium will be discussed. Finally, the economics of titanium metal production also are analyzed as well as the advantages and disadvantages of various alternative extraction methods.

  16. Microfabricated structures and devices featuring nanostructured titania thin films

    NASA Astrophysics Data System (ADS)

    Monkowski, Adam J.

    2007-05-01

    When titanium reacts with hydrogen peroxide at 80°C--100°C, a nanostructured titania (NST) thin film is formed on the titanium surface. This nanostructured film is particularly suited for integration with thin film and bulk microfabrication techniques. The ability to manufacture devices in a batch format is a principal advantage of microfabrication-based production. To reliably produce arrays of micro-patterned NST thin films on the wafer scale, a patterning guideline must be considered. The formation of NST relies on a re-deposition process; adequate ti-peroxo species must be generated and remain at the solid-solution interface. Numerical analysis of the characteristic transient diffusion behavior for various micro-patterns has been compared with experimental data to generate a criterion to guide the design of NST micro-patterns. Wafer scale arrays of NST micro gas-sensors have been fabricated using standard thin film techniques. Sensing elements are 20 mum on a side. High sensitivity to hydrogen is achieved by modification of the sensors with platinum nanoparticles. When exposed to a 10 mT partial pressure of hydrogen at 250°C, the functionalized devices exhibit more than one order of magnitude resistance decrease with a response time of approximately 7 sec. Titanium microstructures formed using the titanium ICP deep etch (TIDE) process have been integrated with NST films to produce an ordered nanostructure-microstructure composite (3D-NST). The process developed allows for the incorporation of a planar top surface, advantageous for bonding and sealing applications, in which the nanostructured thin film is formed only on feature sidewalls and floors. When titanium microstructures are spaced less than 1 mum apart, titania nanostructures bridge adjacent features. NST and 3D-NST structures have been assembled and tested in a dye-sensitized solar cell (DSSC) device. The NST film is approximately 900nm thick; this yielded a DSSC with an efficiency of 1.8%, similar

  17. Surface modification of titanium and titanium alloys by ion implantation.

    PubMed

    Rautray, Tapash R; Narayanan, R; Kwon, Tae-Yub; Kim, Kyo-Han

    2010-05-01

    Titanium and titanium alloys are widely used in biomedical devices and components, especially as hard tissue replacements as well as in cardiac and cardiovascular applications, because of their desirable properties, such as relatively low modulus, good fatigue strength, formability, machinability, corrosion resistance, and biocompatibility. However, titanium and its alloys cannot meet all of the clinical requirements. Therefore, to improve the biological, chemical, and mechanical properties, surface modification is often performed. In view of this, the current review casts new light on surface modification of titanium and titanium alloys by ion beam implantation.

  18. Tensile and creep properties of titanium-vanadium, titanium-molybdenum, and titanium-niobium alloys

    NASA Technical Reports Server (NTRS)

    Gray, H. R.

    1975-01-01

    Tensile and creep properties of experimental beta-titanium alloys were determined. Titanium-vanadium alloys had substantially greater tensile and creep strength than the titanium-niobium and titanium-molybdenum alloys tested. Specific tensile strengths of several titanium-vanadium-aluminum-silicon alloys were equivalent or superior to those of commercial titanium alloys to temperatures of 650 C. The Ti-50V-3Al-1Si alloy had the best balance of tensile strength, creep strength, and metallurgical stability. Its 500 C creep strength was far superior to that of a widely used commercial titanium alloy, Ti-6Al-4V, and almost equivalent to that of newly developed commercial titanium alloys.

  19. Nanostructured composite reinforced material

    DOEpatents

    Seals, Roland D [Oak Ridge, TN; Ripley, Edward B [Knoxville, TN; Ludtka, Gerard M [Oak Ridge, TN

    2012-07-31

    A family of materials wherein nanostructures and/or nanotubes are incorporated into a multi-component material arrangement, such as a metallic or ceramic alloy or composite/aggregate, producing a new material or metallic/ceramic alloy. The new material has significantly increased strength, up to several thousands of times normal and perhaps substantially more, as well as significantly decreased weight. The new materials may be manufactured into a component where the nanostructure or nanostructure reinforcement is incorporated into the bulk and/or matrix material, or as a coating where the nanostructure or nanostructure reinforcement is incorporated into the coating or surface of a "normal" substrate material. The nanostructures are incorporated into the material structure either randomly or aligned, within grains, or along or across grain boundaries.

  20. Titanium alkoxide compound

    DOEpatents

    Boyle, Timothy J.

    2007-08-14

    A titanium alkoxide composition is provided, as represented by the chemical formula (OC.sub.6H.sub.5N).sub.2Ti(OC.sub.6H.sub.5NH.sub.2).sub.2. As prepared, the compound is a crystalline substance with a hexavalent titanium atom bonded to two OC.sub.6H.sub.5NH.sub.2 groups and two OC.sub.6H.sub.5N groups with a theoretical molecular weight of 480.38, comprising 60.01% C, 5.04% H and 11.66% N.

  1. Cytotoxic activity of new neodymium (III) complexes of bis-coumarins.

    PubMed

    Kostova, Irena; Manolov, Ilia; Momekov, Georgi

    2004-09-01

    Complexes of neodymium (III) with bis-coumarins: 3,3'-benzylidene-bis(4-hydroxy-2H-1-benzopyran-2-one); bis(4-hydroxy-2-oxo-2H-chromen-3-yl)-piridin-2-yl-methane; bis(4-hydroxy-2-oxo-2H-chromen-3-yl)-piridin-4-yl-methane; bis(4-hydroxy-2-oxo-2H-chromen-3-yl)-(1H-pyrazol-3-yl)-methane were synthesized by reaction of neodymium (III) salt and the ligands, in amounts equal to metal:ligand molar ratio of 1:2. The complexes were prepared by adding an aqueous solution of neodymium (III) salt to an aqueous solution of the ligand subsequently raising the pH of the mixture gradually to ca. 5.0 by adding dilute solution of sodium hydroxide. The neodymium (III) complexes with bis-coumarins were characterized by different physicochemical methods-elemental analysis, IR-, (1)H- and (13)C-NMR-spectroscopies and mass-spectral data. The spectral data of neodymium (III) complexes were interpreted on the basis of comparison with the spectra of the free ligands. This analysis showed that in the Nd (III) complexes the ligands coordinated to the metal ion through both deprotonated hydroxyl groups. On the basis of the nu(C=O) red shift observed, participation of the carbonyl groups in the coordination to the metal ion was also suggested. Cytotoxic screening by MTT assay was carried out. The complexes were tested on HL-60, HL-60/Dox and SKW-3 cell lines. The overall results from the preliminary screening program revealed that all of the new Nd (III) complexes reach 50% inhibition of the malignant cells proliferation and thus could be considered as biologically active. On the basis of the IC(50) values obtained compounds Nd(L(1))(OH).H(2)O and Nd(L(3))(OH).2H(2)O were found to exert superior activity in comparison to the remaining complexes.

  2. Fabrication of layered nanostructures by successive electron beam induced deposition with two precursors: protective capping of metallic iron structures.

    PubMed

    Schirmer, M; Walz, M-M; Papp, C; Kronast, F; Gray, A X; Balke, B; Cramm, S; Fadley, C S; Steinrück, H-P; Marbach, H

    2011-11-25

    We report on the stepwise generation of layered nanostructures via electron beam induced deposition (EBID) using organometallic precursor molecules in ultra-high vacuum (UHV). In a first step a metallic iron line structure was produced using iron pentacarbonyl; in a second step this nanostructure was then locally capped with a 2-3 nm thin titanium oxide-containing film fabricated from titanium tetraisopropoxide. The chemical composition of the deposited layers was analyzed by spatially resolved Auger electron spectroscopy. With spatially resolved x-ray absorption spectroscopy at the Fe L₃ edge, it was demonstrated that the thin capping layer prevents the iron structure from oxidation upon exposure to air.

  3. Synthesis of 0.1% & 0.2% neodymium doped barium zirconium titanate (BaZr{sub 0.2}Ti{sub 0.8}O{sub 3}) and study of their dielectric behaviour

    SciTech Connect

    Kumar, Anil Kumar, Vipin; Gupta, Merry; Ghumman, S. S.

    2015-08-28

    Efforts have been made to ease process of producing widely used multilayered ceramics of Barium Zirconium Titanium Oxides and study their dielectric behaviour and structural properties. For this purpose, adequate proportions of Barium Carbonate, Zirconium Oxide and Titanium Oxide were taken and hand milled for 2 hours. Neodymium composition of the order of 0.1% and 0.2% was used for doping to weight percentage of BaZr0.2Ti0.8O3. The samples were authenticated using raw data obtained from Bruker AXS D8 advance Copper KL alpha source XRD equipment. Further, the samples were studied for their phase transition, composition, single phase perovskite structure using XRD technique. The technique has also been applied to know formation of stable homogeneous solid solution from XRD parameters. The other physical parameters like the morphology, micro structural information, crystal arrangements and topography have also been observed through SEM. The SEM has revealed information related to grain size development and composition of sample with fine agglomerates. For complete study of the compounds the atomic and weight composition has also been examined by Electron Dispersive Spectroscopy patterns. The comparison has been made with other works on ceramics at various frequencies and has yielded very interesting results.

  4. Evidence of antibacterial activity on titanium surfaces through nanotextures

    NASA Astrophysics Data System (ADS)

    Seddiki, O.; Harnagea, C.; Levesque, L.; Mantovani, D.; Rosei, F.

    2014-07-01

    Nosocomial infections (Nis) are a major concern for public health. As more and more of the pathogens responsible for these infections are antibiotic resistant, finding new ways to overcome them is a major challenge for biomedical research. We present a method to reduce Nis spreading by hindering bacterial adhesion in its very early stage. This is achieved by reducing the contact interface area between the bacterium and the surface by nanoengineering the surface topography. In particular, we studied the Escheria Coli adhesion on titanium surfaces exhibiting different morphologies, that were obtained by a combination of mechanical polishing and chemical etching. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) characterization revealed that the titanium surface is modified at both micro- and nano-scale. X-ray Photoelectron Spectroscopy (XPS) revealed that the surfaces have the same composition before and after piranha treatment, consisting mainly of TiO2. Adhesion tests showed a significant reduction in bacterial accumulation on nanostructured surfaces that had the lowest roughness over large areas. SEM images acquired after bacterial culture on different titanium substrates confirmed that the polished titanium surface treated one hour in a piranha solution at a temperature of 25 °C has the lowest bacterial accumulation among all the surfaces tested. This suggests that the difference observed in bacterial adhesion between the different surfaces is due primarily to surface topography.

  5. Diameter of titanium nanotubes influences anti-bacterial efficacy

    NASA Astrophysics Data System (ADS)

    Ercan, Batur; Taylor, Erik; Alpaslan, Ece; Webster, Thomas J.

    2011-07-01

    Bacterial infection of in-dwelling medical devices is a growing problem that cannot be treated by traditional antibiotics due to the increasing prevalence of antimicrobial resistance and biofilm formation. Here, due to changes in surface parameters, it is proposed that bacterial adhesion can be prevented through nanosurface modifications of the medical device alone. Toward this goal, titanium was created to possess nanotubular surface topographies of highly controlled diameters of 20, 40, 60, or 80 nm, sometimes followed by heat treatment to control chemistry and crystallinity, through a novel anodization process. For the first time it was found that through the control of Ti surface parameters including chemistry, crystallinity, nanotube size, and hydrophilicity, significantly changed responses of both Staphylococcus epidermidis and Staphylococcus aureus (pathogens relevant for orthopaedic and other medical device related infections) were measured. Specifically, heat treatment of 80 nm diameter titanium tubes produced the most robust antimicrobial effect of all surface treatment parameters tested. This study provides the first step toward understanding the surface properties of nano-structured titanium that improve tissue growth (as has been previously observed with nanotubular titanium), while simultaneously reducing infection without the use of pharmaceutical drugs.

  6. Thermally unstable hydrides of titanium aluminide Ti3Al

    NASA Astrophysics Data System (ADS)

    Kazantseva, N. V.; Popov, A. G.; Mushnikov, N. V.; Skripov, A. V.; Soloninin, A. V.; Aleksashin, B. A.; Novozhenov, V. I.; Sazonova, V. A.; Kharisova, A. G.

    2011-04-01

    The hydrogen capacity of (Ti, Nb)3Al titanium aluminides subjected to mechanical activation in a hydrogen atmosphere has been studied. It has been shown that the application of this procedure allows one to prepare thermally unstable titanium aluminide (Ti3Al) hydrides with a high hydrogen content (to 2.6 wt %) at room temperature and normal pressure; in this case, no special requirements for the hydrogen purity are placed. The thermally unstable nanostructured Ti3Al hydrides were found to exhibit a higher hydrogen mobility as compared to that of the microcrystalline hydrides. Low niobium additions (to 2.1 at %) have been found to decrease the hydrogen capacity. Experiments on the preparation of bulk samples from the hydride powders obtained were performed.

  7. Sorting Titanium Welding Rods

    NASA Technical Reports Server (NTRS)

    Ross, W. D., Jr.; Brown, R. L.

    1985-01-01

    Three types of titanium welding wires identified by their resistance to current flow. Welding-wire tester quickly identifies unknown titaniumalloy wire by touching wire with test probe, and comparing meter response with standard response. Before touching wire, tip of test probe dipped into an electrolyte.

  8. Sintering titanium powders

    SciTech Connect

    Gerdemann, Stephen J.; Alman, David E.

    2005-09-01

    Recently, there has been renewed interest in low-cost titanium. Near-net-shape powder metallurgy offers the potential of manufacturing titanium articles without costly and difficult forming and machining operations; hence, processing methods such as conventional press-and-sinter, powder forging and powder injection molding are of interest. The sintering behavior of a variety of commercial and experimental titanium powders was studied. Commercial powders were acquired that were produced different routes: (i) sponge fines from the primary titanium processing; (ii) via the hydride-dehydride process; and (iii) gas atomization. The influence of vacuum sintering time (0.5 to 32 hrs) and temperature (1200, 1275 or 1350°C) on the microstructure (porosity present) of cold pressed powders was studied. The results are discussed in terms of the difference in powder characteristics, with the aim of identify the characteristics required for full density via press-and-sinter processing. Near-net-shape tensile bars were consolidated via cold pressed and sintered. After sintering, a sub-set of the tensile bars was hot-isostatic pressed (HIPed). The microstructure and properties of the bars were compared in the sintered and HIPed conditions.

  9. Bioactive macroporous titanium surface layer on titanium substrate.

    PubMed

    Kim, H M; Kokubo, T; Fujibayashi, S; Nishiguchi, S; Nakamura, T

    2000-12-05

    A macroporous titanium surface layer is often formed on titanium and titanium alloy implants for morphological fixation of the implants to bone via bony ingrowth into the porous structure. The surface of titanium metal was recently shown to become highly bioactive by being subjected to 5.0 M-NaOH treatment at 60 degrees C for 24 h and subsequent heat treatment at 600 degrees C for 1 h. In the present study, the NaOH and heat treatments were applied to a macroporous titanium surface layer formed on titanium substrate by a plasma spraying method. The NaOH and heat treatments produced an uniform amorphous sodium titanate layer on the surface of the porous titanium. The sodium titanate induced a bonelike apatite formation in simulated body fluid at an early soaking period, whereby the apatite layer grew uniformly along the surface and cross-sectional macrotextures of the porous titanium. This indicates that the NaOH and heat treatments lead to a bioactive macroporous titanium surface layer on titanium substrate. Such a bioactive macroporous layer on an implant is expected not only to enhance bony ingrowth into the porous structure, but also to provide a chemical integration with bone via apatite formation on its surface in the body.

  10. Nanostructured Protective Coatings

    DTIC Science & Technology

    2006-01-01

    potential superior wear resistance properties. The Nanostructured Protective Coatings (NPC) program was designed to establish a collaborative team of...understanding of PVD parameters, depositing coatings on practical substrates such as the Ti6Al4V used for turbine blades , and developing a versatile...Nanostructured Protective Coatings (NPC) program was designed to establish a collaborative team of three entities (Pennsylvania State University

  11. Understanding the biological responses of nanostructured metals and surfaces

    NASA Astrophysics Data System (ADS)

    Lowe, Terry C.; Reiss, Rebecca A.

    2014-08-01

    Metals produced by Severe Plastic Deformation (SPD) offer distinct advantages for medical applications such as orthopedic devices, in part because of their nanostructured surfaces. We examine the current theoretical foundations and state of knowledge for nanostructured biomaterials surface optimization within the contexts that apply to bulk nanostructured metals, differentiating how their microstructures impact osteogenesis, in particular, for Ultrafine Grained (UFG) titanium. Then we identify key gaps in the research to date, pointing out areas which merit additional focus within the scientific community. For example, we highlight the potential of next-generation DNA sequencing techniques (NGS) to reveal gene and non-coding RNA (ncRNA) expression changes induced by nanostructured metals. While our understanding of bio-nano interactions is in its infancy, nanostructured metals are already being marketed or developed for medical devices such as dental implants, spinal devices, and coronary stents. Our ability to characterize and optimize the biological response of cells to SPD metals will have synergistic effects on advances in materials, biological, and medical science.

  12. Narrow titanium oxide nanowires induced by femtosecond laser pulses on a titanium surface

    NASA Astrophysics Data System (ADS)

    Li, Hui; Li, Xian-Feng; Zhang, Cheng-Yun; Tie, Shao-Long; Lan, Sheng

    2017-02-01

    The evolution of the nanostructure induced on a titanium (Ti) surface with increasing irradiation pulse number by using a 400-nm femtosecond laser was examined by using scanning electron microscopy. High spatial frequency periodic structures of TiO2 parallel to the laser polarization were initially observed because of the laser-induced oxidation of the Ti surface and the larger efficacy factor of TiO2 in this direction. Periodically aligned TiO2 nanowires with featured width as small as 20 nm were obtained. With increasing pulse number, however, low spatial frequency periodic structures of Ti perpendicular to the laser polarization became dominant because Ti possesses a larger efficacy factor in this direction. The competition between the high- and low-spatial frequency periodic structures is in good agreement with the prediction of the efficacy factor theory and it should also be observed in the femtosecond laser ablation of other metals which are easily oxidized in air.

  13. Neodymium-doped phosphate fiber lasers with an all-solid microstructured inner cladding.

    PubMed

    Zhang, Guang; Zhou, Qinling; Yu, Chunlei; Hu, Lili; Chen, Danping

    2012-06-15

    We report on high-power fiber lasers based on index-guiding, all-solid neodymium-doped (Nd-doped) phosphate photonic crystal fiber (PCF) with a hexagonal-shaped inner cladding. The optimum fiber laser with a 36 cm length active fiber, generated up to 7.92 W output power at 1053 nm, which benefited from a high absorption coefficient for pump power due to its noncircular inner cladding. The guiding properties of the all-solid PCF were also investigated. A stable mode with a donut-shaped profile and a power-dependent laser beam quality have been observed experimentally and analyzed.

  14. [Some effects of the neodymium ion on the cell wall structure of Staphyloccocus aruea].

    PubMed

    Huo, Guang Hua; Zhang, Dong Yan; Zhang, Tong

    2007-12-01

    The aim of this research is to study the effect of neodymium ion on the cell wall structure of Staphyloccocus aruea using transmission electron microscope, amino acid analyzer, infrared absorption spectrometry (IR). Experimental results show that Nd3+ can change the shape and the structure of the cell wall of Staphyloccocus aruea NdCl3 with lower concentration than the bacteriostatic concentration can help to synthesize the cell wall structure of Staphyloccocus aruea. Nd3+ with higher concentration than the bacteriostatic concentration can break the peptide bond and the hydrogen bond so as to break the net structure in the peptideoglycan cell.

  15. Neodymium and lead isotope evidence for enriched early Archean crust in North America

    NASA Technical Reports Server (NTRS)

    Bowring, Samuel A.; Housh, Todd B.; Isachsen, Clark E.; Podosek, Frank A.; King, Janet E.

    1989-01-01

    Neodymium and lead isotope measurements and uranium-lead zircon geochronology from Archaean gneisses of the Slave Province in the Northwest Territories of Canada are reported. The gneisses contain zircons with cores older than 3.842 Gyr and an epsilon(Nd) (3.7 Gyr) of - 4.8. This is the oldest reported chondritic model age for a terrestrial sample and provides evidence for strongly enriched pre-3.8-Gyr crust, a reservoir complementary to the depleted mantle already in existence by 3.8 Gyr before the present.

  16. Laser amplifier based on a neodymium glass rod 150 mm in diameter

    SciTech Connect

    Shaykin, A A; Fokin, A P; Soloviev, A A; Kuzmin, A A; Shaikin, I A; Burdonov, K F; Khazanov, E A; Charukhchev, A V

    2014-05-30

    A unique large-aperture neodymium glass rod amplifier is experimentally studied. The small-signal gain distribution is measured at different pump energies. The aperture-averaged gain is found to be 2.3. The stored energy (500 J), the maximum possible pump pulse repetition rate, and the depolarisation in a single pulse and in a series of pulses with a repetition rate of one pulse per five minutes are calculated based on the investigations performed. It is shown that the use of this amplifier at the exit of the existing laser can increase the output pulse energy from 300 to 600 J. (lasers)

  17. Neodymium neutron transmission and capture measurements and development of a new transmission detector

    NASA Astrophysics Data System (ADS)

    Barry, Devin P.

    Neodymium is a 235U fission product and is important in reactor neutronic calculations. The aim of this thesis is to improve upon the existing neutron cross section data of neodymium. Neutron capture and transmission measurements were performed by the time-of-flight technique at the Rensselaer Polytechnic Institute LINAC using metallic neodymium samples. The capture measurements were made at the 25-m flight station with a 16-segment Nal multiplicity detector, and the transmission measurements were performed at 15-m and 25-m flight stations, respectively, with 6Li glass scintillation detectors. After the data were collected and reduced, resonance parameters were determined by simultaneously fitting the transmission and capture data with the multilevel R-matrix Bayesian code SAMMY. The resonance parameters for all naturally occurring neodymium isotopes were deduced within the energy range of 1.0 eV to 500 eV. The resulting resonance parameters were used to calculate the capture resonance integral with this energy region and were compared to calculations obtained when using the resonance parameters from ENDF-B/VI. The RPI parameters gave a resonance integral value of 32 +/- 1 barns that is approximately 7% lower than that obtained with the ENDF-B/VI parameters. The current measurements significantly reduce the statistical uncertainties on the resonance parameters when compared with previously published parameters. This thesis also explains the resolution function in detail and discusses its importance when fitting experimental data to extract resonance parameters. More accurate resolution function parameters were determined for epithermal transmission and capture measurements by fitting well known resonances in Uranium-238. Improved transmission bare-bounce target in-beam photomultiplier tube (PMT) resolution function parameters were found and compared to those used previously at the RPI LINAC and a marked improvement in the quality of the fits is shown. In addition

  18. Effect of reactor radiation on the operation of a neodymium inorganic liquid laser

    SciTech Connect

    Dobrovol'skii, A F; Kabakov, D V; Seregin, A A; Seregina, E A; Tikhonov, G V

    2009-02-28

    The radiation parameters of a neodymium liquid laser based on phosphorus oxychloride are measured upon irradiation of the laser medium by neutrons and gamma-rays from a BARS-6 two-zone reactor. This irradiation increases the laser energy by 20%-30% compared to the laser energy in the absence of irradiation. The lasing threshold is observed to decrease with increasing the irradiation dose. In the case of simultaneous optical and nuclear pumping of the laser medium, the free-running regime of laser operation converts to the regime of high-power pulses. (lasers)

  19. Titanium Honeycomb Panel Testing

    NASA Technical Reports Server (NTRS)

    Richards, W. Lance; Thompson, Randolph C.

    1996-01-01

    Thermal-mechanical tests were performed on a titanium honeycomb sandwich panel to experimentally validate the hypersonic wing panel concept and compare test data with analysis. Details of the test article, test fixture development, instrumentation, and test results are presented. After extensive testing to 900 deg. F, non-destructive evaluation of the panel has not detected any significant structural degradation caused by the applied thermal-mechanical loads.

  20. Titanium: light, strong, and white

    USGS Publications Warehouse

    Woodruff, Laurel; Bedinger, George

    2013-01-01

    Titanium (Ti) is a strong silver-gray metal that is highly resistant to corrosion and is chemically inert. It is as strong as steel but 45 percent lighter, and it is twice as strong as aluminum but only 60 percent heavier. Titanium dioxide (TiO2) has a very high refractive index, which means that it has high light-scattering ability. As a result, TiO2 imparts whiteness, opacity, and brightness to many products. ...Because of the unique physical properties of titanium metal and the whiteness provided by TiO2, titanium is now used widely in modern industrial societies.

  1. Titanium fasteners. [for aircraft industry

    NASA Technical Reports Server (NTRS)

    Phillips, J. L.

    1972-01-01

    Titanium fasteners are used in large quantities throughout the aircraft industry. Most of this usage is in aluminum structure; where titanium structure exists, titanium fasteners are logically used as well. Titanium fasteners offer potential weight savings to the designer at a cost of approximately $30 per pound of weight saved. Proper and least cost usage must take into consideration type of fastener per application, galvanic couples and installation characteristics of protective coatings, cosmetic appearance, paint adhesion, installation forces and methods available and fatigue performance required.

  2. Nitrogen photofixation on nanostructured iron titanate films.

    PubMed

    Rusina, Olga; Linnik, Oksana; Eremenko, Anna; Kisch, Horst

    2003-01-20

    A nanostructured iron titanate thin film has been prepared by a sol-gel method from iron(III) chloride and titanium tetraisopropylate. Energy-dispersive X-ray analysis and Mössbauer spectroscopy suggest the presence of a Fe(2)Ti(2)O(7) phase, which was previously obtained as an intermediary phase upon heating ilmenite. In the presence of ethanol or humic acids and traces of oxygen, the novel film photocatalyzes the fixation of dinitrogen to ammonia (17 microM) and nitrate (45 microM). In the first observable reaction step, hydrazine is produced and then undergoes further photoreduction to ammonia. Oxidation of the latter by oxygen affords nitrate as the final product. Since the reaction occurs also in air and with visible light (lambda>455 nm), and since the iron titanate phase may be formed by the weathering of ilmenite minerals, it may be a model for mutual nonenzymatic nitrogen fixation in nature.

  3. Nanostructured Oxides and Sulfides for Thermoelectrics

    NASA Astrophysics Data System (ADS)

    Koumoto, Kunihito

    2011-03-01

    Thermoelectric power generation can be applied to various heat sources, both waste heat and renewable energy, to harvest electricity. Even though each heat source is of a small scale, it would lead to a great deal of energy saving if they are combined and collected, and it would greatly contribute to reducing carbon dioxide emission. We have been engaged in developing novel thermoelectric materials to be used for energy saving and environmental protection and are currently developing nanostructured ceramics for thermoelectric conversion. We have demonstrated a quantum confinement effect giving rise to two dimensional electron gas (2DEG) in a 2D superlattice, STO/STO:Nb (STO: strontium titanate), which could generate giant thermopower while keeping high electrical conductivity. One unit-cell thick Nb-doped well layer was estimated to show ZT=2.4 at 300K. Then, a ``synergistic nanostructuring'' concept incorporating 2DEG grain boundaries as well as nanosizing of grains has been applied to our STO material and 3D superlattice ceramics was designed and proposed. It was verified by numerical simulation that this 3D superlattice ceramics should be capable of showing ZT=1.0 at 300K which is comparable to or even higher than that of conventional bismuth telluride-based thermoelectrics. We have recently proposed titanium disulfide-based misfit-layered compounds as novel TE materials. Insertion of misfit-layers into the van der Waals gaps in layer-structured titanium disulfide thus forming a natural superlattice gives rise to internal nanointerfaces and dramatically reduces its lattice thermal conductivity. ZT value reaches 0.37 at 673 K even without optimization of electronic properties. Our challenge to further increase ZT by controlling their electronic system and superlattice structures will be presented.

  4. Selective Leaching Process for Neodymium Recovery from Scrap Nd-Fe-B Magnet

    NASA Astrophysics Data System (ADS)

    Lee, Ching-Hwa; Chen, Yu-Jung; Liao, Ching-Hua; Popuri, Srinivasa R.; Tsai, Shang-Lin; Hung, Chi-En

    2013-12-01

    Neodymium-iron-boron (Nd-Fe-B) magnets were most widely applied to permanent magnetic products in the world due to their high magnetic force. The increasing growth of scrap Nd-Fe-B magnets resulted in disposal problems and the reduction of neodymium (Nd) valuable resources. In this study, we developed a simple hydrometallurgical precipitation process with pH adjustment to separate and recover Nd 100 pct recovery from scrap Nd-Fe-B magnets. Several physical and chemical methods such as demagnetization, grinding, screening, and leaching processes were also adopted to investigate the recovery of Nd and other metals from scrap Nd-Fe-B magnets. The leaching process was carried out with four leaching reagents such as NaOH, HCl, HNO3, and H2SO4. Batch studies were also conducted to optimize the leaching operating conditions with respect to leaching time, concentration of leaching reagent, temperature, and solid/liquid ratio for both HCl and H2SO4 leaching reagents. Nd was successfully separated and recovered with 75.41 wt pct from optimized H2SO4 leaching solution through precipitation. Further, the purity and weight percentage of the obtained Nd product was analyzed using scanning electron microscopy-energy-dispersive spectroscopy (SEM-EDS) analysis. An X-ray diffraction (XRD) study confirmed the obtained product of Nd was in the form of NdOOH and Nd(OH)3.

  5. Azo calix[4]arene based neodymium(III)-selective PVC membrane sensor.

    PubMed

    Menon, Shobhana K; Modi, Nishith R; Patel, Bhargav; Patel, Manishkumar B

    2011-02-15

    We found that the PVC membrane, containing azo calix[4]arene is a suitable ionophore, exhibited a Nernstian response for neodymium (Nd(3+)) ions (with slope of 19.8±0.2 mV decade(-1) for the triply charged ion) over a wide linear range of 4.0×10(-8) to 1.0×10(-1) mol L(-1) with a detection limit 1.0×10(-8) mol L(-1), a relatively fast response time, in the whole concentration range (<10 s), and a considerable life time at least for four months in the pH range of 4.0-8.0. Furthermore, the electrode revealed high selectivity with respect to all the common alkali, alkaline earth, transition and heavy metal ions, including the members of the lanthanide family other than Nd(3+). Concerning its applications, it was effectively employed for the determination of neodymium ions in industrial waste water as well as in lake water.

  6. Neodymium doped hydroxyapatite theranostic nanoplatforms for colon specific drug delivery applications.

    PubMed

    Victor, Sunita Prem; Paul, Willi; Vineeth, V M; Komeri, Remya; Jayabalan, Muthu; Sharma, Chandra P

    2016-09-01

    Theranostic nanoplatforms integrate therapeutic payloads with diagnostic agents, and help monitor therapeutic response. In this regard, stimuli responsive nanoplatforms further favour combinatorial therapeutic approach that can considerably improve efficacy and specificity of treatment. Herein, we present the engineering of a smart theranostic nanoplatform based on neodymium doped hydroxyapatite (HAN). The presence of neodymium endows the HAN nanoplatforms with near-infrared fluorescence capability. These HAN nanoparticles were then subsequently modified with alginic acid (HANA) to confer pH responsiveness to the synthesized nanoplatforms delivering them to the colon after oral administration. These nanoplatforms possessing optimum size, needle shaped morphology and negative zeta potential, are conducive to cellular internalization. On excitation at 410nm they exhibit near infrared emission at 670nm unraveling their theranostic capabilities. Cytotoxic effects systematically assessed using MTT and live dead assays reveal excellent viability. Raman microscopic imaging technique used to visualize uptake in HeLa cells demonstrate increased uptake from 4 to 16h, with growing cluster size and localization in the cytoplasm. Moreover the concomitant presence of alginic acid manifested advantages of augmented loading and pH dependent release profiles of the model drug, 4 acetyl salicylic acid (4ASA). We could thus establish a theranostic system for early tumour detection, targeted tumour therapy and monitoring of colon cancer that can be administered via the oral route.

  7. Spectroscopic properties of neodymium(III)-containing polyoxometalates in aqueous solution.

    PubMed

    But, Slawomir; Lis, Stefan; Deun, Rik Van; Parac-Vogt, Tatjana N; Görller-Walrand, Christiane; Binnemans, Koen

    2005-11-01

    The spectroscopic properties of the neodymium(III)-containing polyoxometalates (POMs) [Nd(PW(11)O(39))(2)](11-), [Nd(PMo(2)W(9)O(39))(2)](11-), [Nd(PMo(4)W(7)O(39))(2)](11-), [Nd(PMo(6)W(5)O(39))(2)](11-), [Nd(SiMo(2)W(9)O(39))(2)](13-), [Nd(P(2)W(17)O(61))(2)](17-), [NdW(10)O(36)](9-), [NdP(5)W(30)O(110)](12-) and [NdAs(4)W(40)O(140)](25-) are described. Absorption spectra of aqueous solutions of the complexes have been recorded and the transition intensities are parameterised in terms of the Judd-Ofelt intensity parameters Omega(lambda) (lambda=2, 4, 6). Marked differences were found between the luminescence lifetimes of the complexes of the type Nd(POM) and those of the type Nd(POM)(2), due to a better shielding of the neodymium(III) ions from the bulk water molecules in the latter type of complexes.

  8. Simulation of the Magnetic Characteristics and Properties of the Neodymium Compensator of the Stiffness

    NASA Astrophysics Data System (ADS)

    Gurova, E. G.; Gurov, M. G.; Panchenko, Y. V.

    2016-08-01

    This research is devoted to consideration of the possibility to use the software ELCUT for development of the magnetic compensator of the stiffness based on neodymium magnets. The software represents precision enough apparatus to solve the issues of the magnetostatic. The solution of these issues is the most important phase at the stage of the designing and calculation of the magnetic compensator of the stiffness, so as at the beginning we need to find the traction force of the interaction between magnet and magnetic materials to provide necessary falling traction characteristic of the compensator. In this paper the simulated models of the neodymium magnets are shown; the view of the field are calculated, the plots of the distribution and directions of the magnetic field strength and induction vectors are presented. Results, which were obtained during of the simulation, further will be used for designing and creation of the magnetic compensator of the stiffness based on supermagnets. Research & Development is under the scholarship of the President of Russian Federation, order №184 from 10th of March 2015.

  9. Antineoplastic activity of new lanthanide (cerium, lanthanum and neodymium) complex compounds.

    PubMed

    Kostova, Irena; Kostova, Raina; Momekov, Georgi; Trendafilova, Natasha; Karaivanova, Margarita

    2005-01-01

    Cerium (III), lanthanum (III) and neodymium (III) complexes with 3,3'-benzylidenebis[4-hydroxycoumarin] were synthesized in view of their application as cytotoxic agents. The complexes were characterized by different physicochemical methods: elemental analysis, mass spectrometry, 1H NMR, 13C NMR and IR spectroscopy. The spectra of the complexes were interpreted on the basis of comparison with the spectrum of the free ligand. The vibrational analysis showed that in the complexes the ligand coordinated to the metal ion through both deprotonated hydroxyl groups; however, participation of the carbonyl groups in the coordination to the metal ion was also suggested. The evaluation of the cytotoxic activity of the novel lanthanide complexes on HL-60 myeloid cells revealed that they are potent cytotoxic agents. The cerium complex was found to exhibit superior activity in comparison to the lanthanum and neodymium coordination compounds, the latter being the least active. Our data give us reason to conclude that the newly synthesized lanthanide complexes should be submitted to further more detailed pharmacological and toxicological evaluation.

  10. Investigation of Carboxylic Acid-Neodymium Conversion Films on Magnesium Alloy

    NASA Astrophysics Data System (ADS)

    Cui, Xiufang; Liu, Zhe; Lin, Lili; Jin, Guo; Wang, Haidou; Xu, Binshi

    2015-01-01

    The new carboxylic acid-neodymium anhydrous conversion films were successfully prepared and applied on the AZ91D magnesium alloy surface by taking absolute ethyl alcohol as solvent and four kinds of soluble carboxylic acid as activators. The corrosion resistance of the coating was measured by potentiodynamic polarization test in 3.5 wt.% NaCl solution in pH 7.0. The morphology, structure, and constituents of the coating were observed by scanning electron microscope, energy dispersivespectrum, x-ray photoelectron spectrum, and Fourier infrared spectrometer. Results show that corrosion resistance properties of samples coated with four different anhydrous conversion films were improved obviously. The corrosion potential increased, corrosion current density decreased, and polarization resistance increased. Among these four kinds of conversion films the one added with phytic exhibits the best corrosion resistant property. The mechanism of anhydrous-neodymium conversion film formation is also analyzed in this paper. It reveals that the gadolinium conversion coating is mainly composed of stable Nd2O3, MgO, Mg(OH)2, and carboxylate of Nd. And that the sample surface is rich in organic functional groups.

  11. Titanium Optics for Ion Thrusters

    NASA Technical Reports Server (NTRS)

    Soulas, George C.; Haag, Thomas W.; Patterson, Michael J.; Rawlin, Vincent K.

    1999-01-01

    Ion thruster total impulse capability is limited, in part, by accelerator grid sputter erosion. A development effort was initiated to identify a material with a lower accelerator grid volumetric sputter erosion rate than molybdenum, but that could utilize the present NSTAR thruster grid design and fabrication techniques to keep development costs low, and perform as well as molybdenum optics. After comparing the sputter erosion rates of several atomic materials to that of molybdenum at accelerator voltages, titanium was found to offer a 45% reduction in volumetric erosion rates. To ensure that screen grid sputter erosion rates are not higher at discharge chamber potentials, titanium and molybdenum sputter erosion rates were measured at these potentials. Preliminary results showed only a slightly higher volumetric erosion rate for titanium, so that screen grid erosion is insignificant. A number of material, thermal, and mechanical properties were also examined to identify any fabrication, launch environment, and thruster operation issues. Several titanium grid sets were successfully fabricated. A titanium grid set was mounted onto an NSTAR 30 cm engineering model ion thruster and tested to determine optics performance. The titanium optics operated successfully over the entire NSTAR power range of 0.5 to 2.3 kW. Differences in impingement-limited perveances and electron backstreaming limits were found to be due to a larger cold gap for the titanium optics. Discharge losses for titanium grids were lower than those for molybdenum, likely due to a slightly larger titanium screen grid open area fraction. Radial distributions of beam current density with titanium optics were very similar to those with molybdenum optics at all power levels. Temporal electron backstreaming limit measurements showed that titanium optics achieved thermal equilibrium faster than molybdenum optics.

  12. Measuring Strong Nanostructures

    SciTech Connect

    Andy Minor

    2008-10-16

    Andy Minor of Berkeley Lab's National Center for Electron Microscopy explains measuring stress and strain on nanostructures with the In Situ Microscope. More information: http://newscenter.lbl.gov/press-relea...

  13. Measuring Strong Nanostructures

    ScienceCinema

    Andy Minor

    2016-07-12

    Andy Minor of Berkeley Lab's National Center for Electron Microscopy explains measuring stress and strain on nanostructures with the In Situ Microscope. More information: http://newscenter.lbl.gov/press-relea...

  14. Understanding bactericidal performance on ambient light activated TiO2-InVO4 nanostructured films.

    PubMed

    He, Ziming; Xu, Qingchi; Tan, Timothy Thatt Yang

    2011-12-01

    TiO(2)-InVO(4) nanostructured films were coated onto glass substrates and systematically investigated for their bactericidal activities using Escherichia coli (E. coli) as the model bacterium under ambient light illumination. The uniform TiO(2)-InVO(4) nanostructured films were prepared using titanium isopropoxide (TTIP) as the precursor via a simple sol-gel approach. Polyethylenimine (PEI) was used as a surfactant to ensure uniform dispersion of InVO(4) and a sacrificial pore-inducing agent, generating nanostructured films. Compared to unmodified TiO(2) film, the current TiO(2)-InVO(4) films exhibited enhanced bactericidal activities under ambient light illumination. Bacterial cell "photo-fixation" was demonstrated to be crucial in enhancing the bactericidal activity. A bacterial-nanostructured surface interaction mechanism was proposed for the current ambient-light activated nanostructured film.

  15. Nanostructured Carbon Coatings

    DTIC Science & Technology

    2000-01-01

    carbon coatings and explores a very broad range of potentially important carbon nanostructures that may be used in future technologies. A new method ...for the synthesis of nanostructured carbon coatings on the surface of SiC and other metal carbides is described. This method is accomplished through the...With the fall in cost of fullerene powders, this method may become important in the future as a method to produce nanocrystalline diamond free of metal

  16. The application of an assisting gas plasma generator for low- temperature magnetron sputtering of Ti-C-Mo-S antifriction coatings on titanium alloys

    NASA Astrophysics Data System (ADS)

    Potekaev, A. I.; Savostikov, V. M.; Tabachenko, A. N.; Dudarev, E. F.; Melnikova, E. A.; Shulepov, I. A.

    2015-11-01

    The positive effect of assisting influence of high-density gas plasma formed by an independent plasma generator PINK on mechanical and tribological characteristics of Ti-C- Mo-S magnetron coating on titanium alloys at lowered to 350°C temperature of coating regardless of alloy structural condition was revealed by methods of calotest, nanorecognition, scratch testing and frictional material tests. The coating formed by means of a combined magnetron plasma method reduces titanium alloys friction coefficient in multiple times and increases wear resistance by two orders of magnitude. At the same time the mechanical properties of ultra-fine-grained titanium alloys obtained by nanostructuring do not deteriorate.

  17. Architectures for Nanostructured Batteries

    NASA Astrophysics Data System (ADS)

    Rubloff, Gary

    2013-03-01

    Heterogeneous nanostructures offer profound opportunities for advancement in electrochemical energy storage, particularly with regard to power. However, their design and integration must balance ion transport, electron transport, and stability under charge/discharge cycling, involving fundamental physical, chemical and electrochemical mechanisms at nano length scales and across disparate time scales. In our group and in our DOE Energy Frontier Research Center (www.efrc.umd.edu) we have investigated single nanostructures and regular nanostructure arrays as batteries, electrochemical capacitors, and electrostatic capacitors to understand limiting mechanisms, using a variety of synthesis and characterization strategies. Primary lithiation pathways in heterogeneous nanostructures have been observed to include surface, interface, and both isotropic and anisotropic diffusion, depending on materials. Integrating current collection layers at the nano scale with active ion storage layers enhances power and can improve stability during cycling. For densely packed nanostructures as required for storage applications, we investigate both ``regular'' and ``random'' architectures consistent with transport requirements for spatial connectivity. Such configurations raise further important questions at the meso scale, such as dynamic ion and electron transport in narrow and tortuous channels, and the role of defect structures and their evolution during charge cycling. Supported as part of the Nanostructures for Electrical Energy Storage, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DESC0001160

  18. Development of a Reliable Analytical Method for Liquid Anion-Exchange Extraction and Separation of Neodymium(III)

    PubMed Central

    Kokare, Balasaheb N.; Kamble, Ganesh S.; Sargar, Balasaheb M.; Anuse, Mansing A.

    2012-01-01

    The liquid-liquid extraction of neodymium(III) from succinate media (0.06 M) has been studied at pH 6.0 with the solution of 0.1 M of N-n-octylaniline in xylene when equilibrium is maintained for 5 min. The back-extraction of neodymium(III) has been performed by using 0.1 M HClO4. The effect of various parameters, such as pH, equilibrium time, extractant concentration, stripping agents, organic diluents, and aqueous to organic volume ratio on the extraction of neodymium(III) has been studied. On the basis of slope analysis, the stoichiometry of the extracted species was determined as 1 : 1 : 2 [RR′NH2+Nd(succinate)2−](org). The method is free from interference of large number cations and anions. The method was used for the selective extraction of neodymium(III) from its binary mixture with U(VI), Zr(IV), Nb(V), La(III), Th(IV), Ce(IV), and Y(III). The proposed method is selective and was successfully applied to the synthetic mixtures to show the practical utility of the extractant. PMID:22701373

  19. Development of a reliable analytical method for liquid anion-exchange extraction and separation of neodymium(III).

    PubMed

    Kokare, Balasaheb N; Kamble, Ganesh S; Sargar, Balasaheb M; Anuse, Mansing A

    2012-01-01

    The liquid-liquid extraction of neodymium(III) from succinate media (0.06 M) has been studied at pH 6.0 with the solution of 0.1 M of N-n-octylaniline in xylene when equilibrium is maintained for 5 min. The back-extraction of neodymium(III) has been performed by using 0.1 M HClO₄. The effect of various parameters, such as pH, equilibrium time, extractant concentration, stripping agents, organic diluents, and aqueous to organic volume ratio on the extraction of neodymium(III) has been studied. On the basis of slope analysis, the stoichiometry of the extracted species was determined as 1 : 1 : 2 [RR'NH₂⁺Nd(succinate)₂⁻](org). The method is free from interference of large number cations and anions. The method was used for the selective extraction of neodymium(III) from its binary mixture with U(VI), Zr(IV), Nb(V), La(III), Th(IV), Ce(IV), and Y(III). The proposed method is selective and was successfully applied to the synthetic mixtures to show the practical utility of the extractant.

  20. Understanding bactericidal performance on ambient light activated TiO2-InVO4 nanostructured films

    NASA Astrophysics Data System (ADS)

    He, Ziming; Xu, Qingchi; Yang Tan, Timothy Thatt

    2011-12-01

    TiO2-InVO4 nanostructured films were coated onto glass substrates and systematically investigated for their bactericidal activities using Escherichia coli (E. coli) as the model bacterium under ambient light illumination. The uniform TiO2-InVO4 nanostructured films were prepared using titanium isopropoxide (TTIP) as the precursor via a simple sol-gel approach. Polyethylenimine (PEI) was used as a surfactant to ensure uniform dispersion of InVO4 and a sacrificial pore-inducing agent, generating nanostructured films. Compared to unmodified TiO2 film, the current TiO2-InVO4 films exhibited enhanced bactericidal activities under ambient light illumination. Bacterial cell ``photo-fixation'' was demonstrated to be crucial in enhancing the bactericidal activity. A bacterial-nanostructured surface interaction mechanism was proposed for the current ambient-light activated nanostructured film.TiO2-InVO4 nanostructured films were coated onto glass substrates and systematically investigated for their bactericidal activities using Escherichia coli (E. coli) as the model bacterium under ambient light illumination. The uniform TiO2-InVO4 nanostructured films were prepared using titanium isopropoxide (TTIP) as the precursor via a simple sol-gel approach. Polyethylenimine (PEI) was used as a surfactant to ensure uniform dispersion of InVO4 and a sacrificial pore-inducing agent, generating nanostructured films. Compared to unmodified TiO2 film, the current TiO2-InVO4 films exhibited enhanced bactericidal activities under ambient light illumination. Bacterial cell ``photo-fixation'' was demonstrated to be crucial in enhancing the bactericidal activity. A bacterial-nanostructured surface interaction mechanism was proposed for the current ambient-light activated nanostructured film. Electronic supplementary information (ESI) available: Photocatalytic activity test procedure and results, AFM images, EDX results, LSCM images, and wettability results. See DOI: 10.1039/c1nr11126d

  1. Final Technical Report: Nanostructured Shape Memory ALloys

    SciTech Connect

    Wendy Crone; Walter Drugan; Arthur Ellis; John Perepezko

    2005-07-28

    With this grant we explored the properties that result from combining the effects of nanostructuring and shape memory using both experimental and theoretical approaches. We developed new methods to make nanostructured NiTi by melt-spinning and cold rolling fabrication strategies, which elicited significantly different behavior. A template synthesis method was also used to created nanoparticles. In order to characterize the particles we created, we developed a new magnetically-assisted particle manipulation technique to manipulate and position nanoscale samples for testing. Beyond characterization, this technique has broader implications for assembly of nanoscale devices and we demonstrated promising applications for optical switching through magnetically-controlled scattering and polarization capabilities. Nanoparticles of nickel-titanium (NiTi) shape memory alloy were also produced using thin film deposition technology and nanosphere lithography. Our work revealed the first direct evidence that the thermally-induced martensitic transformation of these films allows for partial indent recovery on the nanoscale. In addition to thoroughly characterizing and modeling the nanoindentation behavior in NiTi thin films, we demonstrated the feasibility of using nanoindentation on an SMA film for write-read-erase schemes for data storage.

  2. Precision Cleaning Titanium Components

    SciTech Connect

    Hand, T.E.; Bohnert, G.W.

    2000-02-02

    Clean bond surfaces are critical to the operation of diffusion bonded titanium engine components. These components can be contaminated with machining coolant, shop dirt, and fingerprints during normal processing and handling. These contaminants must be removed to achieve acceptable bond quality. As environmental concerns become more important in manufacturing, elimination of the use of hazardous materials is desired. For this reason, another process (not using nitric-hydrofluoric acid solution) to clean titanium parts before bonding was sought. Initial cleaning trials were conducted at Honeywell to screen potential cleaning techniques and chemistries. During the initial cleaning process screening phase, Pratt and Whitney provided Honeywell with machined 3 inch x 3 inch x 1 inch titanium test blocks. These test blocks were machined with a water-based machining coolant and exposed to a normal shop environment and handling. (Honeywell sectioned one of these blocks into smaller samples to be used for additional cleanliness verification analyses.) The sample test blocks were ultrasonically cleaned in alkaline solutions and AUGER analysis was used by Honeywell FM and T to validate their cleanliness. This information enabled selection of final cleaning techniques and solutions to be used for the bonding trials. To validate Honeywell's AUGER data and to verify the cleaning processes in actual situations, additional sample blocks were cleaned (using the chosen processes) and then bonded. The bond quality of the test blocks was analyzed according to Pratt and Whitney's requirements. The Charpy impact testing was performed according to ASTM procedure {number_sign}E-23. Bond quality was determined by examining metallographic samples of the bonded test blocks for porosity along the bondline.

  3. Polyisocyanides of titanium.

    PubMed

    Rayón, Víctor M; Redondo, Pilar; Valdés, Haydee; Barrientos, Carmen; Largo, Antonio

    2009-02-26

    Neutral Ti[CN](n) complexes have been investigated with quantum chemistry techniques. According to our theoretical predictions, these complexes are shown to prefer isocyanide arrangements. Therefore, these compounds are good candidates to be the first polyisocyanides to be characterized. The theoretical calculations predict Ti(NC)(4), a methane-like tetrahedral structure with four isocyanide ligands, as the most stable neutral complex. The fact that the isocyanide ligand is a better pi-donor than the cyanide one seems to be the key factor for the preference for isocyanides in neutral titanium complexes.

  4. Process for stabilization of titanium silicide particulates within titanium aluminide containing metal matrix composites

    SciTech Connect

    Christodoulou, L.; Williams, J.C.; Riley, M.A.

    1990-04-10

    This paper describes a method for forming a final composite material comprising titanium silicide particles within a titanium aluminide containing matrix. It comprises: contacting titanium, silicon and aluminum at a temperature sufficient to initiate a reaction between the titanium and silicon to thereby form a first composite comprising titanium silicide particles dispersed within an aluminum matrix; admixing the first composite with titanium and zirconium to form a mixture; heating the mixture to a temperature sufficient to convert at least a portion of the aluminum matrix to titanium aluminide; and recovering a final composite material comprising titanium silicide particles dispersed within a titanium aluminide containing matrix.

  5. Novel nanostructured hydroxyapatite coating for dental and orthopedic implants

    NASA Astrophysics Data System (ADS)

    Liu, Huinan; Jiang, Wenping; Malshe, Ajay

    2009-09-01

    A novel hybrid coating process, combining NanoSpray® (built on electrostatic spray coating) technology with microwave sintering process, was developed for synthesizing hydroxyapatite- (HA-) based nanostructured coating with favorable properties for dental and orthopedic implants. Specifically, HA nanoparticles were deposited on commercially pure titanium substrates using NanoSpray technique to produce the HA coating, which was then sintered in a microwave furnace under controlled conditions. The study showed that the use of NanoSpray followed by microwave sintering results in nanoscale HA coating for dental/orthopedic application.

  6. Milestones in Functional Titanium Dioxide Thermal Spray Coatings: A Review

    NASA Astrophysics Data System (ADS)

    Gardon, M.; Guilemany, J. M.

    2014-04-01

    Titanium dioxide has been the most investigated metal oxide due to its outstanding performance in a wide range of applications, chemical stability and low cost. Coating processes that can produce surfaces based on this material have been deeply studied. Nevertheless, the necessity of coating large areas by means of rapid manufacturing processes renders laboratory-scale techniques unsuitable, leading to a noteworthy interest from the thermal spray (TS) community in the development of significant intellectual property and a large number of scientific publications. This review unravels the relationship between titanium dioxide and TS technologies with the aim of providing detailed information related to the most significant achievements, lack of knowhow, and performance of TS TiO2 functional coatings in photocatalytic, biomedical, and other applications. The influence of thermally activated techniques such as atmospheric plasma spray and high-velocity oxygen fuel spray on TiO2 feedstock based on powders and suspensions is revised; the influence of spraying parameters on the microstructural and compositional changes and the final active behavior of the coating have been analyzed. Recent findings on titanium dioxide coatings deposited by cold gas spray and the capacity of this technology to prevent loss of the nanostructured anatase metastable phase are also reviewed.

  7. Synthesis and characterization of TiO2 nanostructure thin films grown by thermal CVD

    NASA Astrophysics Data System (ADS)

    Rizal, Umesh; Das, Soham; Kumar, Dhruva; Swain, Bhabani S.; Swain, Bibhu P.

    2016-04-01

    Thermal Chemical Vapor Deposition (CVD) deposited Titanium dioxide nanostructures (TiO2-NSs) were grown by using Ti powder and O2 precursors on Si/SiO2 (100) substrate. The microstructure and vibration properties of TiO2-NSs were characterized by Fourier transform infrared (FTIR), SEM, and photoluminescence (PL) spectroscopy. The role of O2 flow rate on TiO2-NSs revealed decreased deposition rate, however, surface roughness has been increased resulted into formation of nanostructure thin films.

  8. Nanostructures having high performance thermoelectric properties

    DOEpatents

    Yang, Peidong; Majumdar, Arunava; Hochbaum, Allon I; Chen, Renkun; Delgado, Raul Diaz

    2014-05-20

    The invention provides for a nanostructure, or an array of such nanostructures, each comprising a rough surface, and a doped or undoped semiconductor. The nanostructure is an one-dimensional (1-D) nanostructure, such a nanowire, or a two-dimensional (2-D) nanostructure. The nanostructure can be placed between two electrodes and used for thermoelectric power generation or thermoelectric cooling.

  9. Nanostructures having high performance thermoelectric properties

    DOEpatents

    Yang, Peidong; Majumdar, Arunava; Hochbaum, Allon I.; Chen, Renkun; Delgado, Raul Diaz

    2015-12-22

    The invention provides for a nanostructure, or an array of such nanostructures, each comprising a rough surface, and a doped or undoped semiconductor. The nanostructure is an one-dimensional (1-D) nanostructure, such a nanowire, or a two-dimensional (2-D) nanostructure. The nanostructure can be placed between two electrodes and used for thermoelectric power generation or thermoelectric cooling.

  10. Enhanced functions of vascular cells on nanostructured Ti for improved stent applications.

    PubMed

    Choudhary, Saba; Haberstroh, Karen M; Webster, Thomas J

    2007-07-01

    Vascular tissue possesses numerous nanostructured surface features, but most metallic vascular stents proposed to restore blood flow are smooth at the nanoscale. Thus, the objective of the present study was to determine in vitro vascular cell functions on nanostructured titanium (Ti) compared to conventional commercially pure (c.p.) Ti. Results of this study showed for the first time greater competitive adhesion of endothelial versus vascular smooth muscle cells on nanostructured Ti compared to conventional Ti after 4 hours. Moreover, when cultured separately, increased endothelial and vascular smooth muscle cell density was observed on nanostructured Ti compared to conventional c.p. Ti after 1, 3, and 5 days; endothelial cells formed confluent monolayers before vascular smooth muscle cells on nanostructured Ti. Results also showed greater total amounts of collagen and elastin synthesis by vascular cells when cultured on nanostructured Ti. Since a major mode of failure of conventional vascular stents is the overgrowth of smooth muscle cells compared to endothelial cells, these results suggest that while the functions of both types of vascular cells were promoted on nanostructured c.p. Ti, endothelial cell functions (of particular importance, cell density or confluence) were enhanced over that of vascular smooth muscle cells. Thus, the present in vitro study showed that vascular stents composed of nanometer c.p. Ti particles may invoke advantageous cellular responses for improved stent applications.

  11. Electrorotation of titanium microspheres.

    PubMed

    Arcenegui, Juan J; Ramos, Antonio; García-Sánchez, Pablo; Morgan, Hywel

    2013-04-01

    Electrorotation (ROT) data for solid titanium micrometer-sized spheres in an electrolyte are presented for three different ionic conductivities, over the frequency range of 10 Hz to 100 kHz. The direction of rotation was found to be opposite to the direction of rotation of the electric field vector (counterfield electrorotation), with a single rotation peak. The maximum rotation rate occurs at a frequency of the order of the reciprocal RC time constant for charging the particle double layer capacitance through the resistor of the electrolyte bulk. A model for the electrical torque acting on a metallic sphere is presented, using a constant phase element impedance to describe the metal/electrolyte interface. The titanium spheres are much denser than the electrolyte and rest on the bottom substrate. Therefore, the electrical and viscous torques near a wall are considered in the analysis. Good agreement is found between the predicted and measured rotational speed as a function of frequency. Theory shows that there is no effect of induced charge electroosmotic flow on the ROT, as observed experimentally.

  12. Compaction of Titanium Powders

    SciTech Connect

    Gerdemann, Stephen,J; Jablonski, Paul, J

    2011-05-01

    Accurate modeling of powder densification has been an area of active research for more than 60 years. The earliest efforts were focused on linearization of the data because computers were not readily available to assist with curve-fitting methods. In this work, eight different titanium powders (three different sizes of sponge fines<150 {micro}m,<75 {micro}m, and<45 {micro}m; two different sizes of a hydride-dehydride [HDH]<75 {micro}m and<45 {micro}m; an atomized powder; a commercially pure [CP] Ti powder from International Titanium Powder [ITP]; and a Ti 6 4 alloy powder) were cold pressed in a single-acting die instrumented to collect stress and deformation data during compaction. From these data, the density of each compact was calculated and then plotted as a function of pressure. The results show that densification of all the powders, regardless of particle size, shape, or chemistry, can be modeled accurately as the sum of an initial density plus the sum of a rearrangement term and a work-hardening term. These last two terms are found to be a function of applied pressure and take the form of an exponential rise.

  13. Compaction of Titanium Powders

    SciTech Connect

    Stephen J. Gerdemann; Paul D. Jablonski

    2010-11-01

    Accurate modeling of powder densification has been an area of active research for more than 60 years. The earliest efforts were focused on linearization of the data because computers were not readily available to assist with curve-fitting methods. In this work, eight different titanium powders (three different sizes of sponge fines <150 μm, <75 μm, and < 45 μm; two different sizes of a hydride-dehydride [HDH] <75 μm and < 45 μm; an atomized powder; a commercially pure [CP] Ti powder from International Titanium Powder [ITP]; and a Ti 6 4 alloy powder) were cold pressed in a single-acting die instrumented to collect stress and deformation data during compaction. From these data, the density of each compact was calculated and then plotted as a function of pressure. The results show that densification of all the powders, regardless of particle size, shape, or chemistry, can be modeled accurately as the sum of an initial density plus the sum of a rearrangement term and a work-hardening term. These last two terms are found to be a function of applied pressure and take the form of an exponential rise.

  14. Titanium-dioxide nanotube p-n homojunction diode

    SciTech Connect

    Alivov, Yahya E-mail: pnagpal@colorado.edu; Ding, Yuchen; Singh, Vivek; Nagpal, Prashant E-mail: pnagpal@colorado.edu

    2014-12-29

    Application of semiconductors in functional optoelectronic devices requires precise control over their doping and formation of junction between p- and n-doped semiconductors. While doped thin films have led to several semiconductor devices, need for high-surface area nanostructured devices for photovoltaic, photoelectrochemical, and photocatalytic applications has been hindered by lack of desired doping in nanostructures. Here, we show titanium-dioxide (TiO{sub 2}) nanotubes doped with nitrogen (N) and niobium (Nb) as acceptors and donors, respectively, and formation of TiO{sub 2} nanotubes p-n homojunction. This TiO{sub 2}:N/TiO{sub 2}:Nb homojunction showed distinct diode-like behaviour with rectification ratio of 1115 at ±5 V and exhibited good photoresponse for ultraviolet light (λ = 365 nm) with sensitivity of 0.19 A/W at reverse bias of −5 V. These results can have important implications for development of nanostructured metal-oxide solar-cells, photodiodes, LED's, photocatalysts, and photoelectrochemical devices.

  15. Nanostructured materials in potentiometry.

    PubMed

    Düzgün, Ali; Zelada-Guillén, Gustavo A; Crespo, Gastón A; Macho, Santiago; Riu, Jordi; Rius, F Xavier

    2011-01-01

    Potentiometry is a very simple electrochemical technique with extraordinary analytical capabilities. It is also well known that nanostructured materials display properties which they do not show in the bulk phase. The combination of the two fields of potentiometry and nanomaterials is therefore a promising area of research and development. In this report, we explain the fundamentals of potentiometric devices that incorporate nanostructured materials and we highlight the advantages and drawbacks of combining nanomaterials and potentiometry. The paper provides an overview of the role of nanostructured materials in the two commonest potentiometric sensors: field-effect transistors and ion-selective electrodes. Additionally, we provide a few recent examples of new potentiometric sensors that are based on receptors immobilized directly onto the nanostructured material surface. Moreover, we summarize the use of potentiometry to analyze processes involving nanostructured materials and the prospects that the use of nanopores offer to potentiometry. Finally, we discuss several difficulties that currently hinder developments in the field and some future trends that will extend potentiometry into new analytical areas such as biology and medicine.

  16. Investigation on microstructure and martensitic transformation of neodymium-added NiTi shape memory alloys

    NASA Astrophysics Data System (ADS)

    Maashaa, Dovchinvanchig; Dorj, Ulzii-Orshikh; Lee, Malrey; Lee, Min Hi; Zhao, Chunwang; Dashjav, Munguntsetseg; Woo, Seon-Mi

    2016-10-01

    The effect of rare earth element neodymium (Nd) addition on the microstructure and martensitic transformation behavior of Ni50Ti50-xNdx (x = 0, 0.1, 0.3, 0.5 and 0.7 at.%) shape memory alloy was investigated by scanning electronic microscope, X-ray diffraction and differential scanning calorimetry. The results show that the microstructure of Ni-Ti-Nd ternary alloy consists of NiNd phase, NiTi2 and the NiTi matrix. A one-step martensitic transformation is observed in the alloys. The martensitic transformation temperature Ms increases sharply increasing 0.1-0.7 at.% Nd content is added.

  17. Calf thymus DNA binding studies of the new neodymium-naproxen complex.

    PubMed

    Huo, Ruina; Xu, Guiqing; Jiang, Xiaoying; Ge, Yao; Xue, Zaikun; Cui, Fengling

    2012-05-01

    Fluorescence spectroscopy in combination with UV absorption spectroscopy was carried out to investigate the interaction between the neodymium-naproxen complex (Nd-NAP) and calf thymus DNA (ctDNA). The experimental results showed that Nd-NAP intercalated with the ctDNA base pairs. Analysis of fluorescence quenching data of Nd-NAP by ctDNA at different temperatures using a Stern-Volmer equation revealed that dynamic and static quenching occurred simultaneously. The binding constants and the number of binding sites at 293 and 310 K were obtained as 2.904 × 10(4) L mol(-1), 1.172 and 2.432 × 10(4) L mol(-1), 1.143, respectively. The thermodynamic parameters ΔG, ΔH, and ΔS calculated at different temperatures indicated that hydrogen bonding and van der Waals force were the main binding forces.

  18. Vacuum ultraviolet field emission lamp consisting of neodymium ion doped lutetium fluoride thin film as phosphor.

    PubMed

    Yanagihara, Masahiro; Tsuji, Takayuki; Yusop, Mohd Zamri; Tanemura, Masaki; Ono, Shingo; Nagami, Tomohito; Fukuda, Kentaro; Suyama, Toshihisa; Yokota, Yuui; Yanagida, Takayuki; Yoshikawa, Akira

    2014-01-01

    A vacuum ultraviolet (VUV) field emission lamp was developed by using a neodymium ion doped lutetium fluoride (Nd(3+) : LuF3) thin film as solid-state phosphor and carbon nanofiber field electron emitters. The thin film was synthesized by pulsed laser deposition and incorporated into the lamp. The cathodoluminescence spectra of the lamp showed multiple emission peaks at 180, 225, and 255 nm. These emission spectra were in good agreement with the spectra reported for the Nd(3+) : LuF3 crystal. Moreover, application of an acceleration voltage effectively increased the emission intensity. These results contribute to the performance enhancement of the lamp operating in the VUV region.

  19. Heavy metals chromium and neodymium reduced phosphorylation level of heat shock protein 27 in human keratinocytes.

    PubMed

    Zhang, Qihao; Zhang, Lei; Xiao, Xue; Su, Zhijian; Zou, Ping; Hu, Hao; Huang, Yadong; He, Qing-Yu

    2010-06-01

    Heavy metals may exert their acute and chronic effects on the human skin through stress signals. In the present study, 2DE-based proteomics was used to analyze the protein expression in human keratinocytes exposed to heavy metals, chromium and neodymium, and 10 proteins with altered expression were identified. Among these proteins, small heat shock protein 27 (HSP27) was up-regulated significantly and the up-regulation was validated by Western blot and immunofluorescence. In addition, the mRNA expression level of HSP27 markedly increased as detected by quantitative PCR. More interestingly, the ratio of phosphorylated HSP27 and total HSP27 significantly decreased in keratinocytes treated with the heavy metals. These findings suggested that heavy metals reduced the phosphorylation level of HSP27, and that the ratio of p-HSP27 and HSP27 may represent a potential marker or additional endpoint for the hazard assessment of skin irritation caused by chemical products.

  20. Vacuum Ultraviolet Field Emission Lamp Consisting of Neodymium Ion Doped Lutetium Fluoride Thin Film as Phosphor

    PubMed Central

    Yanagihara, Masahiro; Tsuji, Takayuki; Yusop, Mohd Zamri; Tanemura, Masaki; Nagami, Tomohito; Fukuda, Kentaro; Suyama, Toshihisa; Yokota, Yuui; Yanagida, Takayuki; Yoshikawa, Akira

    2014-01-01

    A vacuum ultraviolet (VUV) field emission lamp was developed by using a neodymium ion doped lutetium fluoride (Nd3+ : LuF3) thin film as solid-state phosphor and carbon nanofiber field electron emitters. The thin film was synthesized by pulsed laser deposition and incorporated into the lamp. The cathodoluminescence spectra of the lamp showed multiple emission peaks at 180, 225, and 255 nm. These emission spectra were in good agreement with the spectra reported for the Nd3+ : LuF3 crystal. Moreover, application of an acceleration voltage effectively increased the emission intensity. These results contribute to the performance enhancement of the lamp operating in the VUV region. PMID:25302320

  1. Extruded channel waveguides in a neodymium-doped lead-silicate glass for integrated optic applications

    NASA Astrophysics Data System (ADS)

    Mairaj, Arshad K.; Feng, Xian; Hewak, Daniel W.

    2003-10-01

    We report on the development of channel waveguides in a lead-silicate glass through the extrusion technique. An extruded glass slab with four imbedded fibers each with core size of 8 by 2.5 μm in the horizontal and vertical directions was manufactured. These neodymium-doped channel waveguides were in single-mode operation at 808 nm and had attenuation of 0.1 dB cm-1 at 1.06 μm. The measured 4F3/2 lifetime of 488 μs and emission cross section of 2.5×10-20 cm2 were in good agreement with reported values. The integration of multiple glass variants into a single compact platform is presented as a manufacturing route for complex integrated optical waveguides.

  2. Extraction chromatography of neodymium by an organophosphorous extractant supported on various polymeric resins

    SciTech Connect

    Takigawa, D.Y.

    1993-04-01

    Fifteen resins coated with dihexyl-N,N-diethylcarbamoylmethyl phosphonate (CMP) were studied for their extraction of neodymium (Nd) in 4.0 and 7.0 M nitric acid. Resin properties, such as chemical composition and physical morphology, which can influence Nd extraction as well as subsequent resin regeneration (Nd stripping), were identified. Hydrophilic or polar resins coated with CMP efficiently extracted the Nd. Resins initially washed free of residual monomer and solvent before CMP coating outperformed their untreated counterparts. The macroporous styrene-divinylbenzene hydrophobic resins that were high in surface area were less effective supports compared with hydrophilic microporous Aurorez, polybenzimidazole (PBI) and macroporous Amberlite polyacrylic resins. Only one resin, Duolite C-467, showed no measurable improvement in Nd extraction with CMP coating. CMP-coated Aurorez PBI, a microporous and hydrophilic polymeric resin with an average surface area, showed the best overall efficiency for Nd removal and resin regeneration.

  3. Defect characterization in neodymium doped thallium indium disulfide crystals by thermoluminescence measurements

    NASA Astrophysics Data System (ADS)

    Delice, S.; Gasanly, N. M.

    2016-10-01

    Characteristics of defect centers in neodymium doped TlInS2 single crystals have been investigated in virtue of thermoluminescence measurements carried out at low temperatures (10-300 K) with various heating rates between 0.4 and 1.2 K s-1. One glow peak was detected with peak maximum temperature of 26 K at a rate of 0.4 K s-1. The observed glow peak was analyzed using three points and heating rate methods. The analysis results revealed the presence of one trap level with activation energy of 14 meV. Three points method showed that mixed order of kinetic dominates the trapping level. Shift of peak maximum temperature to higher values and decrease in TL intensity were observed as the heating rate was increased progressively. Distribution of traps was demonstrated using an experimental method based on illumination temperature varying between 10 and 14 K.

  4. Influence of neodymium concentration on excitation and emission properties of Nd doped gallium oxide nanocrystalline films

    SciTech Connect

    Podhorodecki, A.; Banski, M.; Misiewicz, J.; Lecerf, C.; Marie, P.; Cardin, J.; Portier, X.

    2010-09-15

    Gallium oxide and more particularly {beta}-Ga{sub 2}O{sub 3} matrix is an excellent material for new generation of devices electrically or optically driven as it is known as the widest band gap transparent conductive oxide. In this paper, the optical properties of neodymium doped gallium oxide films grown by magnetron sputtering have been analyzed. The influence of the Nd ions concentration on the excitation/emission mechanisms of Nd ions and the role of gallium oxide matrix have been investigated. The grain size reduction into gallium oxide films have been observed when concentration of Nd increases. It has been found for all samples that the charge transfer is the main excitation mechanism for Nd ions where defect states play an important role as intermediate states. As a consequence Nd emission efficiency increases with temperature giving rise to most intensive emission at 1087 nm at room temperature.

  5. Influence of neodymium concentration on excitation and emission properties of Nd doped gallium oxide nanocrystalline films

    NASA Astrophysics Data System (ADS)

    Podhorodecki, A.; Banski, M.; Misiewicz, J.; Lecerf, C.; Marie, P.; Cardin, J.; Portier, X.

    2010-09-01

    Gallium oxide and more particularly β-Ga2O3 matrix is an excellent material for new generation of devices electrically or optically driven as it is known as the widest band gap transparent conductive oxide. In this paper, the optical properties of neodymium doped gallium oxide films grown by magnetron sputtering have been analyzed. The influence of the Nd ions concentration on the excitation/emission mechanisms of Nd ions and the role of gallium oxide matrix have been investigated. The grain size reduction into gallium oxide films have been observed when concentration of Nd increases. It has been found for all samples that the charge transfer is the main excitation mechanism for Nd ions where defect states play an important role as intermediate states. As a consequence Nd emission efficiency increases with temperature giving rise to most intensive emission at 1087 nm at room temperature.

  6. Current status and future outlook for bonded neodymium permanent magnets (invited)

    NASA Astrophysics Data System (ADS)

    Croat, J. J.

    1997-04-01

    Bonded neodymium magnets can provide significant size and weight reduction and/or performance enhancement over sintered and, particularly, bonded ferrite permanent magnets and, moreover, provide these benefits at reasonable cost. Primarily for these reasons, these bonded magnets are now used in a wide and growing range of computer peripheral, office automation, and consumer electronic applications and now constitute the fastest growing segment of the permanent magnet market. The current status of these materials will be reviewed. Included is a brief overview of the manufacture of these magnetically isotropic magnets and a discussion of their unique properties and features from the perspective of both bonded magnet producer and user. Major applications are discussed as are some of the factors that will drive the market for these materials in the future. New technical developments, including the status and outlook for anisotropic bonded materials, high remanance isotropic materials and high temperature bonded magnets will also be discussed.

  7. Laser hydrothermal reductive ablation of titanium monoxide: Hydrated TiO particles with modified Ti/O surface

    SciTech Connect

    Blazevska-Gilev, Jadranka; Jandova, Vera; Kupcik, Jaroslav; Bastl, Zdenek; Subrt, Jan; Bezdicka, Petr; Pola, Josef

    2013-01-15

    IR laser- and UV laser-induced ablation of titanium monoxide (TM) in hydrogen (50 Torr) is compared to the same process induced in vacuum and shown to result in deposition of hydrated surface modified nanostructured titanium suboxide films. Complementary analyses of the films deposited in vacuum and in hydrogen by Fourier transform infrared, Raman and X-ray photoelectron spectroscopy, X-ray diffraction and electron microscopy allowed to determine different features of both films and propose a mechanism of surface modification of ejected particles, which involves hydrothermal reduction of TM and subsequent reactions of evolved water. The films exert good adhesion to metal and quartz surfaces and are hydrophobic in spite of having their surface coated with adsorbed water. - Graphical abstract: Laser ablation of titanium monoxide (TiO) in hydrogen involves a sequence of H{sub 2} and H{sub 2}O eliminations and additions and yields hydrated amorphous nanostructured titanium suboxide which is richer in oxygen than TiO. Highlights: Black-Right-Pointing-Pointer IR and UV laser ablated particles of titanium monoxide (TiO) undergo amorphization. Black-Right-Pointing-Pointer Films deposited in vacuum have TiO stoichiometry and are oxidized in atmosphere. Black-Right-Pointing-Pointer Films deposited in hydrogen are hydrated and have more O in topmost layers. Black-Right-Pointing-Pointer Films modification in hydrogen is explained by reactions in hydrogen plasma.

  8. Diffusion bonding of titanium-titanium aluminide-alumina sandwich

    SciTech Connect

    Wickman, H.A.; Chin, E.S.C.; Biederman, R.R.

    1995-12-31

    Diffusion bonding of a metallic-intermetallic-ceramic sandwich is of interest for potential armor applications. Low cost titanium, titanium diboride reinforced titanium aluminide (Ti-48at.%Al), and aluminum oxide are diffusion bonded in a vacuum furnace between 1,000 C and 1,400 C. Metallographic examination of the prior bonding interface showed excellent metallurgical coupling between the Ti-48at.%Al composite and the low cost Ti. A series of microstructures representative of phases consistent with a hypothetical Ti-Al-B phase diagram is visible. The alumina-Ti-48at.%Al interfacial bond is achieved through penetration of titanium-aluminum phases into the existing alumina porosity. A detailed microstructural analysis identifying mechanisms of interfacial bonding will be presented for each interfacial zone.

  9. Beta titanium alloys and their role in the titanium industry

    NASA Astrophysics Data System (ADS)

    Bania, Paul J.

    1994-07-01

    The class of titanium alloys generically referred to as the beta alloys is arguably the most versatile in the titanium family. Since these alloys offer the highest strength-to-weight ratios and deepest hardenability of all titanium alloys, one might expect them to compete favorably for a variety of aerospace applications. To the contrary, however, except for one very successful application (Ti-13V-11Cr-3Al on the SR-71), the beta alloys have remained a very small segment of the industry. As a perspective on this situation, this article reviews some past and present applications of titanium alloys. It also descibes some unique new alloys and applications that promise to reverse historical trends.

  10. Nanostructured materials for hydrogen storage

    DOEpatents

    Williamson, Andrew J.; Reboredo, Fernando A.

    2007-12-04

    A system for hydrogen storage comprising a porous nano-structured material with hydrogen absorbed on the surfaces of the porous nano-structured material. The system of hydrogen storage comprises absorbing hydrogen on the surfaces of a porous nano-structured semiconductor material.

  11. Effect of corrosion products (neodymium iron boron) on oral fibroblast proliferation.

    PubMed

    Evans, R D; McDonald, F

    1995-01-01

    The biological effects of the corrosion products of neodymium iron boron (Nd2Fe14B) magnets are largely unknown. The aim of this study was to identify the types of corrosion product and to evaluate the effect of the corrosion products (CP) of Nd2Fe14B magnets on the proliferation of human oral mucosal fibroblasts. Uncoated Nd2Fe14B magnets were stored in saline at 37 degrees C for 6 months and the corrosion products collected. 100 microL of a cell suspension (human oral mucosal fibroblasts [14 x 10(4) cells/mL]) was aliquoted into 72 wells of a 96-well plate, the remaining plates receiving culture medium only. After 12 h incubation at 37 degrees C, each well then received 100 microL of either (A) culture medium, (B) 100% CP, (C) 50% CP, or (D) 0% CP. The plates were reincubated at 37 degrees C for a further 48, 96, or 144 h. Fibroblast proliferation was assessed using the methylene blue uptake/elution technique. The compounds in the corrosion product were examined using quantitative X-ray analysis. Statistical analysis (ANOVA, Bonferroni's test 0.05, SAS v 6.04), showed that at each time point, the cell numbers in groups B, C, and D were significantly lower than group A. Within groups B, C, and D no significant differences were found, despite the suggestion of a dose response effect. Fibroblast proliferation in the presence of corrosion products was significantly lower than with culture medium. Fibroblast proliferation did occur in the presence of 0, 50, and 100% CP. The actual corrosion products appeared to be salts of iron but 3.2% (+/- 0.6) of neodymium chloride (NdCl3) was found.

  12. The photocatalytic and antibacterial activities of neodymium and iodine doped TiO(2) nanoparticles.

    PubMed

    Jiang, Xuefeng; Yang, Lu; Liu, Peng; Li, Xi; Shen, Jian

    2010-08-01

    A series of photocatalysts were synthesized by neodymium and iodine doped TiO(2). The characteristics of neodymium and iodine doped TiO(2) were evaluated by X-ray diffraction (XRD), UV-vis diffuse reflectance spectra, and scanning electronic microscope (SEM). In the synthesis process, Nd:I:TiO(2) with different doping content (molar ratios) calcined at different temperature was designed. After the photocatalysts were synthesized under different condition, they were compared with each other by photocatalytic degradation of methylene blue (MB). The most efficient catalyst to degrade MB was Nd combined with I doped TiO(2) with molar ratio of 5:10:100 calcined at 400 degrees C. It is anatase crystal and the average size of crystallites was about 6.0 nm. It has absorption spectrometry in the visible light range of 400-550 nm. In addition, compared with pure TiO(2), the doped catalyst also has intense absorption at 528, 587, 683, 750, 808, and 881 nm. The catalytic efficiency was tested by monitoring the photocatalytic degradation, and detriment of MB and bovine serum albumin (BSA). The antibacterial activities were studied by Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The results showed that the optimum doping contents was Nd:I:TiO(2)=5:10:100 (molar ratio) calcined at 400 degrees C, and the synthesized catalyst could inhibit E. coli and S. aureus through damaging their outer membrane (even deteriorated completely) by the irradiation of visible light.

  13. Neodymium in the oceans: a global database, a regional comparison and implications for palaeoceanographic research

    PubMed Central

    Griffiths, Alexander M.; Lambelet, Myriam; Little, Susan H.; Stichel, Torben; Wilson, David J.

    2016-01-01

    The neodymium (Nd) isotopic composition of seawater has been used extensively to reconstruct ocean circulation on a variety of time scales. However, dissolved neodymium concentrations and isotopes do not always behave conservatively, and quantitative deconvolution of this non-conservative component can be used to detect trace metal inputs and isotopic exchange at ocean–sediment interfaces. In order to facilitate such comparisons for historical datasets, we here provide an extended global database for Nd isotopes and concentrations in the context of hydrography and nutrients. Since 2010, combined datasets for a large range of trace elements and isotopes are collected on international GEOTRACES section cruises, alongside classical nutrient and hydrography measurements. Here, we take a first step towards exploiting these datasets by comparing high-resolution Nd sections for the western and eastern North Atlantic in the context of hydrography, nutrients and aluminium (Al) concentrations. Evaluating those data in tracer–tracer space reveals that North Atlantic seawater Nd isotopes and concentrations generally follow the patterns of advection, as do Al concentrations. Deviations from water mass mixing are observed locally, associated with the addition or removal of trace metals in benthic nepheloid layers, exchange with ocean margins (i.e. boundary exchange) and/or exchange with particulate phases (i.e. reversible scavenging). We emphasize that the complexity of some of the new datasets cautions against a quantitative interpretation of individual palaeo Nd isotope records, and indicates the importance of spatial reconstructions for a more balanced approach to deciphering past ocean changes. This article is part of the themed issue ‘Biological and climatic impacts of ocean trace element chemistry’.

  14. Neodymium isotopic characterization of Ross Sea Bottom Water and its advection through the southern South Pacific

    NASA Astrophysics Data System (ADS)

    Basak, Chandranath; Pahnke, Katharina; Frank, Martin; Lamy, Frank; Gersonde, Rainer

    2015-06-01

    Since the inception of the international GEOTRACES program, studies investigating the distribution of trace elements and their isotopes in the global ocean have significantly increased. In spite of this large-scale effort, the distribution of neodymium isotopes (143Nd/144Nd, εNd) and concentrations ([Nd]) in the high latitude South Pacific is still understudied, specifically north of the Antarctic Polar Front (APF). Here we report dissolved Nd isotopes and concentrations from 11 vertical water column profiles from the South Pacific between South America and New Zealand and across the Antarctic frontal system. Results confirm that Ross Sea Bottom Water (RSBW) is represented by an εNd value of ∼ - 7, and for the first time show that these Nd characteristics can be traced into the Southeast Pacific until progressive mixing with ambient Lower Circumpolar Deep Water (LCDW) dilutes this signal north of the APF. That is, εNd behaves conservatively in RSBW, opening a path for studies of past RSBW behavior. Neodymium concentrations show low surface concentrations and a linear increase with depth north of the APF. South of the APF, surface [Nd] is high and increases with depth but remains almost constant below ∼1000 m. This vertical and spatial [Nd] pattern follows the southward shoaling density surfaces of the Southern Ocean and hence suggests supply of Nd to the upper ocean through upwelling of Nd-rich deep water. Low particle abundance due to reduced opal production and seasonal sea ice cover likely contributes to the maintenance of the high upper ocean [Nd] south of the APF. This suggests a dominant lateral transport component on [Nd] and a reduced vertical control on Nd concentrations in the South Pacific south of the APF.

  15. Neodymium in the oceans: a global database, a regional comparison and implications for palaeoceanographic research

    NASA Astrophysics Data System (ADS)

    van de Flierdt, Tina; Griffiths, Alexander M.; Lambelet, Myriam; Little, Susan H.; Stichel, Torben; Wilson, David J.

    2016-11-01

    The neodymium (Nd) isotopic composition of seawater has been used extensively to reconstruct ocean circulation on a variety of time scales. However, dissolved neodymium concentrations and isotopes do not always behave conservatively, and quantitative deconvolution of this non-conservative component can be used to detect trace metal inputs and isotopic exchange at ocean-sediment interfaces. In order to facilitate such comparisons for historical datasets, we here provide an extended global database for Nd isotopes and concentrations in the context of hydrography and nutrients. Since 2010, combined datasets for a large range of trace elements and isotopes are collected on international GEOTRACES section cruises, alongside classical nutrient and hydrography measurements. Here, we take a first step towards exploiting these datasets by comparing high-resolution Nd sections for the western and eastern North Atlantic in the context of hydrography, nutrients and aluminium (Al) concentrations. Evaluating those data in tracer-tracer space reveals that North Atlantic seawater Nd isotopes and concentrations generally follow the patterns of advection, as do Al concentrations. Deviations from water mass mixing are observed locally, associated with the addition or removal of trace metals in benthic nepheloid layers, exchange with ocean margins (i.e. boundary exchange) and/or exchange with particulate phases (i.e. reversible scavenging). We emphasize that the complexity of some of the new datasets cautions against a quantitative interpretation of individual palaeo Nd isotope records, and indicates the importance of spatial reconstructions for a more balanced approach to deciphering past ocean changes. This article is part of the themed issue 'Biological and climatic impacts of ocean trace element chemistry'.

  16. Concentrations and isotopic compositions of neodymium in the eastern Indian Ocean and Indonesian straits

    NASA Astrophysics Data System (ADS)

    Jeandel, Catherine; Thouron, Danièle; Fieux, Michèle

    1998-08-01

    Four profiles of Nd concentration and isotopic composition were determined at two stations in the eastern Indian Ocean along a north/south section between Bali and Port-Hedland and at two others in the Timor and Sumba straits. Neodymium concentrations increase with depth, between 7.2 pmol/L at the surface to 41.7 pmol/L close to the bottom. The ɛ Nd of the different water masses along the section are -7.2 ± 0.2 for the Indian Bottom Waters and -6.1 ± 0.2 for the Indian Deep Waters. The intermediate and thermocline waters are less radiogenic at st-10 than at st-20 (-5.3 ± 0.3 and -3.6 ± 0.2, respectively). In the Timor Passage and Sumba Strait, ɛ Nd of the Indonesian waters is -4.1 ± 0.2 and that of the North Indian Intermediate Waters is -2.6 ± 0.3. These distinct isotopic signals constrain the origins of the different water masses sampled in the eastern Indian Ocean. They fix the limit of the nonradiogenic Antarctic and Indian contributions to the southern part of the section whereas the northern part is influenced by radiogenic Indonesian flows. In addition, the neodymium isotopic composition suggests that in the north, deep waters are influenced by a radiogenic component originating from the Sunda Arch Slope flowing deeper than 1200 m, which was not documented previously. Mixing calculations assess the conservativity of ɛ Nd on the scale of an oceanic basin. The origin of the surprising radiogenic signal of the NIIW is discussed and could result from a remobilization of Nd sediment-hosted on the Java shelf, requiring important dissolved/particulate exchange processes. Such processes, occurring in specific areas, could play an important role in the world ocean Nd budget.

  17. Nanostructured Biomaterials for Regeneration**

    PubMed Central

    Wei, Guobao; Ma, Peter X.

    2009-01-01

    Biomaterials play a pivotal role in regenerative medicine, which aims to regenerate and replace lost/dysfunctional tissues or organs. Biomaterials (scaffolds) serve as temporary 3D substrates to guide neo tissue formation and organization. It is often beneficial for a scaffolding material to mimic the characteristics of extracellular matrix (ECM) at the nanometer scale and to induce certain natural developmental or/and wound healing processes for tissue regeneration applications. This article reviews the fabrication and modification technologies for nanofibrous, nanocomposite, and nanostructured drug-delivering scaffolds. ECM-mimicking nanostructured biomaterials have been shown to actively regulate cellular responses including attachment, proliferation, differentiation and matrix deposition. Nano-scaled drug delivery systems can be successfully incorporated into a porous 3D scaffold to enhance the tissue regeneration capacity. In conclusion, nano-structured biomateials are a very exciting and rapidly expanding research area, and are providing new enabling technologies for regenerative medicine. PMID:19946357

  18. Synthesis of porphyrin nanostructures

    DOEpatents

    Fan, Hongyou; Bai, Feng

    2014-10-28

    The present disclosure generally relates to self-assembly methods for generating porphyrin nanostructures. For example, in one embodiment a method is provided that includes preparing a porphyrin solution and a surfactant solution. The porphyrin solution is then mixed with the surfactant solution at a concentration sufficient for confinement of the porphyrin molecules by the surfactant molecules. In some embodiments, the concentration of the surfactant is at or above its critical micelle concentration (CMC), which allows the surfactant to template the growth of the nanostructure over time. The size and morphology of the nanostructures may be affected by the type of porphyrin molecules used, the type of surfactant used, the concentration of the porphyrin and surfactant the pH of the mixture of the solutions, and the order of adding the reagents to the mixture, to name a few variables.

  19. Gamma titanium aluminide alloys

    SciTech Connect

    Yamaguchi, M.; Inui, H.; Kishida, K.; Matsumuro, M.; Shirai, Y.

    1995-08-01

    Extensive progress and improvements have been made in the science and technology of gamma titanium aluminide alloys within the last decade. In particular, the understanding of their microstructural characteristics and property/microstructure relationships has been substantially deepened. Based on these achievements, various engineering two-phase gamma alloys have been developed and their mechanical and chemical properties have been assessed. Aircraft and automotive industries arc pursuing their introduction for various structural components. At the same time, recent basic studies on the mechanical properties of two-phase gamma alloys, in particular with a controlled lamellar structure have provided a considerable amount of fundamental information on the deformation and fracture mechanisms of the two-phase gamma alloys. The results of such basic studies are incorporated in the recent alloy and microstructure design of two-phase gamma alloys. In this paper, such recent advances in the research and development of the two-phase gamma alloys and industrial involvement are summarized.

  20. Advanced titanium processing

    SciTech Connect

    Hartman, Alan D.; Gerdemann, Stephen J.; Schrems, Karol K.; Holcomb, Gordon R.; Argetsinger, Edward R.; Hansen, Jeffrey S.; Paige, Jack I.; Turner, Paul C.

    2001-01-01

    The Albany Research Center of the U.S. Department of Energy has been investigating a means to form useful wrought products by direct and continuous casting of titanium bars using cold-wall induction melting rather than current batch practices such as vacuum arc remelting. Continuous ingots produced by cold-wall induction melting, utilizing a bottomless water-cooled copper crucible, without slag (CaF2) additions had minor defects in the surface such as ''hot tears''. Slag additions as low as 0.5 weight percent were used to improve the surface finish. Therefore, a slag melted experimental Ti-6Al-4V alloy ingot was compared to a commercial Ti-6Al-4V alloy ingot in the areas of physical, chemical, mechanical, and corrosion attributes to address the question, ''Are any detrimental effects caused by slag addition''?

  1. Hemocompatibility of titanium nitride.

    PubMed

    Dion, I; Baquey, C; Candelon, B; Monties, J R

    1992-10-01

    The left ventricular assist device is based on the principle of the Maillard-Wenkel rotative pump. The materials which make up the pump must present particular mechanical, tribological, thermal and chemical properties. Titanium nitride (TiN) because of its surface properties and graphite because of its bulk characteristics have been chosen. The present study evaluated the in vitro hemocompatibility of TiN coating deposited by the chemical vapor deposition process. Protein adsorption, platelet retention and hemolysis tests have been carried out. In spite of some disparities, the TiN behavior towards albumin and fibrinogen is interesting, compared with the one of a reference medical grade elastomer. The platelet retention test gives similar results as those achieved with the same elastomer. The hemolysis percentage is near to zero. TiN shows interesting characteristics, as far as mechanical and tribological problems are concerned, and presents very encouraging blood tolerability properties.

  2. Hydrogen in titanium alloys

    SciTech Connect

    Wille, G W; Davis, J W

    1981-04-01

    The titanium alloys that offer properties worthy of consideration for fusion reactors are Ti-6Al-4V, Ti-6Al-2Sn-4Zr-2Mo-Si (Ti-6242S) and Ti-5Al-6Sn-2Zr-1Mo-Si (Ti-5621S). The Ti-6242S and Ti-5621S are being considered because of their high creep resistance at elevated temperatures of 500/sup 0/C. Also, irradiation tests on these alloys have shown irradiation creep properties comparable to 20% cold worked 316 stainless steel. These alloys would be susceptible to slow strain rate embrittlement if sufficient hydrogen concentrations are obtained. Concentrations greater than 250 to 500 wppm hydrogen and temperatures lower than 100 to 150/sup 0/C are approximate threshold conditions for detrimental effects on tensile properties. Indications are that at the elevated temperature - low hydrogen pressure conditions of the reactors, there would be negligible hydrogen embrittlement.

  3. Nanostructured Solar Cells.

    PubMed

    Chen, Guanying; Ning, Zhijun; Ågren, Hans

    2016-08-09

    We are glad to announce the Special Issue "Nanostructured Solar Cells", published in Nanomaterials. This issue consists of eight articles, two communications, and one review paper, covering major important aspects of nanostructured solar cells of varying types. From fundamental physicochemical investigations to technological advances, and from single junction solar cells (silicon solar cell, dye sensitized solar cell, quantum dots sensitized solar cell, and small molecule organic solar cell) to tandem multi-junction solar cells, all aspects are included and discussed in this issue to advance the use of nanotechnology to improve the performance of solar cells with reduced fabrication costs.

  4. Plasmonics in nanostructures.

    PubMed

    Fang, Zheyu; Zhu, Xing

    2013-07-26

    Plasmonics has developed into one of the rapidly growing research topics for nanophotonics. With advanced nanofabrication techniques, a broad variety of nanostructures can be designed and fabricated for plasmonic devices at nanoscale. Fundamental properties for both surface plasmon polaritons (SPP) and localized surface plasmons (LSP) arise a new insight and understanding for the electro-optical device investigations, such as plasmonic nanofocusing, low-loss plasmon waveguide and active plasmonic detectors for energy harvesting. Here, we review some typical functional plasmonic nanostructures and nanosmart devices emerging from our individual and collaborative research works.

  5. Nanostructured Solar Cells

    PubMed Central

    Chen, Guanying; Ning, Zhijun; Ågren, Hans

    2016-01-01

    We are glad to announce the Special Issue “Nanostructured Solar Cells”, published in Nanomaterials. This issue consists of eight articles, two communications, and one review paper, covering major important aspects of nanostructured solar cells of varying types. From fundamental physicochemical investigations to technological advances, and from single junction solar cells (silicon solar cell, dye sensitized solar cell, quantum dots sensitized solar cell, and small molecule organic solar cell) to tandem multi-junction solar cells, all aspects are included and discussed in this issue to advance the use of nanotechnology to improve the performance of solar cells with reduced fabrication costs.

  6. Controlled implant/soft tissue interaction by nanoscale surface modifications of 3D porous titanium implants.

    PubMed

    Rieger, Elisabeth; Dupret-Bories, Agnès; Salou, Laetitia; Metz-Boutigue, Marie-Helene; Layrolle, Pierre; Debry, Christian; Lavalle, Philippe; Vrana, Nihal Engin

    2015-06-07

    Porous titanium implants are widely employed in the orthopaedics field to ensure good bone fixation. Recently, the use of porous titanium implants has also been investigated in artificial larynx development in a clinical setting. Such uses necessitate a better understanding of the interaction of soft tissues with porous titanium structures. Moreover, surface treatments of titanium have been generally evaluated in planar structures, while the porous titanium implants have complex 3 dimensional (3D) architectures. In this study, the determining factors for soft tissue integration of 3D porous titanium implants were investigated as a function of surface treatments via quantification of the interaction of serum proteins and cells with single titanium microbeads (300-500 μm in diameter). Samples were either acid etched or nanostructured by anodization. When the samples are used in 3D configuration (porous titanium discs of 2 mm thickness) in vivo (in subcutis of rats for 2 weeks), a better integration was observed for both anodized and acid etched samples compared to the non-treated implants. If the implants were also pre-treated with rat serum before implantation, the integration was further facilitated. In order to understand the underlying reasons for this effect, human fibroblast cell culture tests under several conditions (directly on beads, beads in suspension, beads encapsulated in gelatin hydrogels) were conducted to mimic the different interactions of cells with Ti implants in vivo. Physical characterization showed that surface treatments increased hydrophilicity, protein adsorption and roughness. Surface treatments also resulted in improved adsorption of serum albumin which in turn facilitated the adsorption of other proteins such as apolipoprotein as quantified by protein sequencing. The cellular response to the beads showed considerable difference with respect to the cell culture configuration. When the titanium microbeads were entrapped in cell

  7. Homogeneous liquid-liquid extraction of neodymium(III) by choline hexafluoroacetylacetonate in the ionic liquid choline bis(trifluoromethylsulfonyl)imide.

    PubMed

    Onghena, Bieke; Jacobs, Jeroen; Van Meervelt, Luc; Binnemans, Koen

    2014-08-14

    The ionic liquid choline bis(trifluoromethylsulfonyl)imide, [Chol][Tf2N], was used for the extraction of neodymium(III), in combination with choline hexafluoroacetylacetonate, [Chol][hfac], as the extractant. The binary mixture of [Chol][Tf2N] and water shows temperature-dependent phase behavior, with an upper critical solution temperature of 72 °C. A novel extraction technique, homogeneous liquid-liquid extraction (HLLE), was applied to this solvent system. HLLE is based on the use of thermomorphic solvent mixtures and has the advantage of forming a homogeneous phase during mixing. Extraction is not kinetically hindered by an interface and the extraction equilibrium is reached faster than in the case of heterogeneous mixing in conventional solvent extraction. Several extraction parameters were studied for the extraction of neodymium(III) with [Chol][hfac]: temperature, pH, extractant concentration and loading of the ionic liquid phase. A speciation study was performed to determine the stoichiometry of the extracted neodymium(III) complex and a plausible extraction mechanism is proposed. Neodymium is extracted as a tetrakis hexafluoroacetylacetonate complex with one choline cation as counter ion. The crystal structure of the extracted complex showed the presence of a coordination bond between the choline counter ion and the neodymium(III) center, resulting in a coordination number of nine. The stripping of the loaded neodymium and the influence of acid and extractant concentrations on the phase behavior of the [Chol][Tf2N]-H2O system were investigated.

  8. Modification of the Surface Topography and Composition of Ultrafine and Coarse Grained Titanium by Chemical Etching

    PubMed Central

    Nazarov, Denis V.; Zemtsova, Elena G.; Solokhin, Alexandr Yu.; Valiev, Ruslan Z.; Smirnov, Vladimir M.

    2017-01-01

    In this study, we present the detailed investigation of the influence of the etching medium (acidic or basic Piranha solutions) and the etching time on the morphology and surface relief of ultrafine grained (UFG) and coarse grained (CG) titanium. The surface relief and morphology have been studied by means of scanning electron microscopy (SEM), atomic force microscopy (AFM), and the spectral ellipsometry. The composition of the samples has been determined by X-ray fluorescence analysis (XRF) and X-ray Photoelectron Spectroscopy (XPS). Significant difference in the etching behavior of UFG and CG titanium has been found. UFG titanium exhibits higher etching activity independently of the etching medium. Formed structures possess higher homogeneity. The variation of the etching medium and time leads to micro-, nano-, or hierarchical micro/nanostructures on the surface. Significant difference has been found between surface composition for UFG titanium etched in basic and acidic Piranha solution. Based on the experimental data, the possible reasons and mechanisms are considered for the formation of nano- and microstructures. The prospects of etched UFG titanium as the material for implants are discussed. PMID:28336849

  9. A "clickable" titanium surface platform.

    PubMed

    Watson, Matthew A; Lyskawa, Joël; Zobrist, Cédric; Fournier, David; Jimenez, Maude; Traisnel, Michel; Gengembre, Léon; Woisel, Patrice

    2010-10-19

    A straightforward functionalization of a titanium surface using "click" chemistry is reported. A "clickable" titanium surface platform was prepared by the immobilization of an azide-functionalized electroactive catechol anchor and was subsequently derivatized with an electroactive or fluorinated probe via the CuAAC (copper-catalyzed azide-alkyne cycloaddition) reaction. The course of the reaction was investigated by contact angle, XPS, and electrochemical measurements.

  10. Photocatalytic Activity of Nanostructured Anatase Coatings Obtained by Cold Gas Spray

    NASA Astrophysics Data System (ADS)

    Gardon, M.; Fernández-Rodríguez, C.; Garzón Sousa, D.; Doña-Rodríguez, J. M.; Dosta, S.; Cano, I. G.; Guilemany, J. M.

    2014-10-01

    This article describes a photocatalytic nanostructured anatase coating deposited by cold gas spray (CGS) supported on titanium sub-oxide (TiO2- x ) coatings obtained by atmospheric plasma spray (APS) onto stainless steel cylinders. The photocatalytic coating was homogeneous and preserved the composition and nanostructure of the starting powder. The inner titanium sub-oxide coating favored the deposition of anatase particles in the solid state. Agglomerated nano-TiO2 particles fragmented when impacting onto the hard surface of the APS TiO2- x bond coat. The rough surface provided by APS provided an ideal scenario for entrapping the nanostructured particles, which may be adhered onto the bond coat due to chemical bonding; a possible bonding mechanism is described. Photocatalytic experiments showed that CGS nano-TiO2 coating was active for photodegrading phenol and formic acid under aqueous conditions. The results were similar to the performance obtained by competitor technologies and materials such as dip-coating P25® photocatalysts. Disparity in the final performance of the photoactive materials may have been caused by differences in grain size and the crystalline composition of titanium dioxide.

  11. Low cost titanium--myth or reality

    SciTech Connect

    Turner, Paul C.; Hartman, Alan D.; Hansen, Jeffrey S.; Gerdemann, Stephen J.

    2001-01-01

    In 1998, approximately 57,000 tons of titanium metal was consumed in the form of mill products (1). Only about 5% of the 4 million tons of titanium minerals consumed each year is used to produce titanium metal, with the remainder primarily used to produce titanium dioxide pigment. Titanium metal production is primarily based on the direct chlorination of rutile to produce titanium tetrachloride, which is then reduced to metal using the Kroll magnesium reduction process. The use of titanium is tied to its high strength-to-weight ratio and corrosion resistance. Aerospace is the largest application for titanium, and titanium cost has prevented its use in non-aerospace applications including the automotive and heavy vehicle industries.

  12. Synthesis of silver-titanium dioxide nanocomposites for antimicrobial applications

    NASA Astrophysics Data System (ADS)

    Yang, X. H.; Fu, H. T.; Wang, X. C.; Yang, J. L.; Jiang, X. C.; Yu, A. B.

    2014-08-01

    Silver-titanium dioxide (Ag-TiO2) nanostructures have attracted increasing attention because of unique functional properties and potential applications in many areas such as photocatalysis, antibacterial, and self-cleaning coatings. In this study, Ag@TiO2 core-shell nanostructures and Ag-decorated TiO2 particles (TiO2@Ag) (the size of these two nanoparticles is ranging from 200-300 nm) have been synthesized by a developed facile but efficient method. These two types of hybrid nanostructures, characterized by various advanced techniques (TEM, XRD, BET and others), exhibit unique functional properties particularly in antibacterial toward Gram negative Escherichia coli, as a case study. Specifically: (i) the TiO2@Ag nanoparticles are superior in bacterial growth inhibition in standard culture conditions (37 °C incubator) to the Ag@TiO2 core-shell ones, in which silver may dominate the antibacterial performance; (ii) while after UV irradiation treatment, the Ag@TiO2 core-shell nanoparticles exhibit better performance in killing grown bacteria than the TiO2@Ag ones, probably because of the Ag cores facilitating charge separation for TiO2, and thus produce more hydroxyl radicals on the surface of the TiO2 particles; and (iii) without UV irradiation, both TiO2@Ag and Ag@TiO2 nanostructures show poor capabilities in killing mature bacteria. These findings would be useful for designing hybrid metal oxide nanocomposites with desirable functionalities in bioapplications in terms of sterilization, deodorization, and water purification.

  13. Building Nanostructures with Drugs

    PubMed Central

    Ma, Wang; Cheetham, Andrew G.

    2016-01-01

    The convergence of nanoscience and drug delivery has prompted the formation of the field of nanomedicine, one that exploits the novel physicochemical and biological properties of nanostructures for improved medical treatments and reduced side effects. Until recently, this nanostructure-mediated strategy considered the drug to be solely a biologically active compound to be delivered, and its potential as a molecular building unit remained largely unexplored. A growing trend within nanomedicine has been the use of drug molecules to build well-defined nanostructures of various sizes and shapes. This strategy allows for the creation of self-delivering supramolecular nanomedicines containing a high and fixed drug content. Through rational design of the number and type of the drug incorporated, the resulting nanostructures can be tailored to assume various morphologies (e.g. nanospheres, rods, nanofibers, or nanotubes) for a particular mode of administration such as systemic, topical, and local delivery. This review covers the recent advances in this rapidly developing field, with the aim of providing an in-depth evaluation of the exciting opportunities that this new field could create to improve the current clinical practice of nanomedicine. PMID:27066106

  14. Nanostructured catalyst supports

    DOEpatents

    Zhu, Yimin; Goldman, Jay L.; Qian, Baixin; Stefan, Ionel C.

    2012-10-02

    The present invention relates to SiC nanostructures, including SiC nanopowder, SiC nanowires, and composites of SiC nanopowder and nanowires, which can be used as catalyst supports in membrane electrode assemblies and in fuel cells. The present invention also relates to composite catalyst supports comprising nanopowder and one or more inorganic nanowires for a membrane electrode assembly.

  15. Atomically Traceable Nanostructure Fabrication.

    PubMed

    Ballard, Josh B; Dick, Don D; McDonnell, Stephen J; Bischof, Maia; Fu, Joseph; Owen, James H G; Owen, William R; Alexander, Justin D; Jaeger, David L; Namboodiri, Pradeep; Fuchs, Ehud; Chabal, Yves J; Wallace, Robert M; Reidy, Richard; Silver, Richard M; Randall, John N; Von Ehr, James

    2015-07-17

    Reducing the scale of etched nanostructures below the 10 nm range eventually will require an atomic scale understanding of the entire fabrication process being used in order to maintain exquisite control over both feature size and feature density. Here, we demonstrate a method for tracking atomically resolved and controlled structures from initial template definition through final nanostructure metrology, opening up a pathway for top-down atomic control over nanofabrication. Hydrogen depassivation lithography is the first step of the nanoscale fabrication process followed by selective atomic layer deposition of up to 2.8 nm of titania to make a nanoscale etch mask. Contrast with the background is shown, indicating different mechanisms for growth on the desired patterns and on the H passivated background. The patterns are then transferred into the bulk using reactive ion etching to form 20 nm tall nanostructures with linewidths down to ~6 nm. To illustrate the limitations of this process, arrays of holes and lines are fabricated. The various nanofabrication process steps are performed at disparate locations, so process integration is discussed. Related issues are discussed including using fiducial marks for finding nanostructures on a macroscopic sample and protecting the chemically reactive patterned Si(100)-H surface against degradation due to atmospheric exposure.

  16. Emerging double helical nanostructures.

    PubMed

    Zhao, Meng-Qiang; Zhang, Qiang; Tian, Gui-Li; Wei, Fei

    2014-08-21

    As one of the most important and land-mark structures found in nature, a double helix consists of two congruent single helices with the same axis or a translation along the axis. This double helical structure renders the deoxyribonucleic acid (DNA) the crucial biomolecule in evolution and metabolism. DNA-like double helical nanostructures are probably the most fantastic yet ubiquitous geometry at the nanoscale level, which are expected to exhibit exceptional and even rather different properties due to the unique organization of the two single helices and their synergistic effect. The organization of nanomaterials into double helical structures is an emerging hot topic for nanomaterials science due to their promising exceptional unique properties and applications. This review focuses on the state-of-the-art research progress for the fabrication of double-helical nanostructures based on 'bottom-up' and 'top-down' strategies. The relevant nanoscale, mesoscale, and macroscopic scale fabrication methods, as well as the properties of the double helical nanostructures are included. Critical perspectives are devoted to the synthesis principles and potential applications in this emerging research area. A multidisciplinary approach from the scope of nanoscience, physics, chemistry, materials, engineering, and other application areas is still required to the well-controlled and large-scale synthesis, mechanism, property, and application exploration of double helical nanostructures.

  17. Nanostructured catalyst supports

    DOEpatents

    Zhu, Yimin; Goldman, Jay L.; Qian, Baixin; Stefan, Ionel C.

    2015-09-29

    The present invention relates to SiC nanostructures, including SiC nanopowder, SiC nanowires, and composites of SiC nanopowder and nanowires, which can be used as catalyst supports in membrane electrode assemblies and in fuel cells. The present invention also relates to composite catalyst supports comprising nanopowder and one or more inorganic nanowires for a membrane electrode assembly.

  18. Complex WS 2 nanostructures

    NASA Astrophysics Data System (ADS)

    Whitby, R. L. D.; Hsu, W. K.; Lee, T. H.; Boothroyd, C. B.; Kroto, H. W.; Walton, D. R. M.

    2002-06-01

    A range of elegant tubular and conical nanostructures has been created by template growth of (WS 2) n layers on the surfaces of single-walled carbon nanotube bundles. The structures exhibit remarkably perfect straight segments together with interesting complexities at the intersections, which are discussed here in detail in order to enhance understanding of the structural features governing tube growth.

  19. Bioaccumulation of cerium and neodymium by Bacillus cereus isolated from rare earth environments of Chavara and Manavalakurichi, India.

    PubMed

    Challaraj Emmanuel, E S; Vignesh, V; Anandkumar, B; Maruthamuthu, S

    2011-10-01

    Rare earth elements (REEs) are among the common minerals in the Rare earth environment that are very precious and also enhance soil properties. The aim of this present study is to evaluate the accumulation of REEs by bacterial isolates of rare earth environment. Morphological and biochemical characterization were done for 37 bacterial isolates and also molecular studies were carried out using 16S rRNA sequencing method. The assessment of REEs composition in soil samples of Chavara and Manavalakurichi analyzed using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) showed the abundance of Cerium and Neodymium among lanthanides. The bioaccumulation study of rare earth elements by Bacillus cereus were accomplished employing FT-IR spectrum and ICP-OES analysis. The significant accumulation of rare earth elements especially Cerium and Neodymium was noticed in Bacillus cereus isolated from rare earth environment.

  20. Interfacial reactions in titanium-matrix composites

    SciTech Connect

    Yang, J.M.; Jeng, S.M. )

    1989-11-01

    A study of the interfacial reaction characteristics of SiC fiber-reinforced titanium aluminide and disordered titanium alloy composites has determined that the matrix alloy compositions affect the microstructure and the distribution of the reaction products, as well as the growth kinetics of the reaction zones. The interfacial reaction products in the ordered titanium aluminide composite are more complicated than those in the disordered titanium-alloy composite. The activation energy of the interfacial reaction in the ordered titanium aluminide composite is also higher than that in the disordered titanium alloy composite. Designing an optimum interface is necessary to enhance the reliability and service life at elevated temperatures. 16 refs.

  1. Variations in the neodymium and strontium isotopic composition and REE content of molluscan shells from the Cretaceous Western Interior seaway

    SciTech Connect

    Whittaker, S.G.; Kyser, T.K. )

    1993-08-01

    Rare earth element concentrations, [epsilon][sub ND](T) values, and strontium isotopic compositions of mollusc shells were used to trace variations in the neodymium and strontium isotopic composition of the epicontinental Late Cretaceous Western Interior seaway of North America. Rare earth element patterns are different in aragonite and calcite produced by the molluscs endemic to the seaway, indicating that either mineralogical control or possibly scavenging by organic films associated with the different phases of biogenic carbonate resulted in differential partitioning of the REEs from seawater during shell formation. The biogenic carbonate also may contain REEs associated with Fe-flocs trapped in the shells during growth, but these flocs cannot result in different REE patterns of aragonite and calcite produced by the molluscs. The neodymium isotopic composition of the Western Interior seaway is inferred to have varied 13 [epsilon]-units over 20 My as a result of incursions of seawater from the Arctic Ocean and Gulf of Mexico, river influx from tectonically active terranes, benthic diagenetic fluxes, and volcanic ash falls. Ash from a variety of volcanic centers in western North America was significant in producing rapid and marked changes in [sup 143]Nd/[sup 144]Nd ratios of the seaway, and abrupt regional variations in neodymium isotopic composition of the seaway make the construction of an accurate neodymium isotope evolution curve difficult for this basin. Strontium isotopic compositions of the mollusc shells indicate the [sup 87]Sr/[sup 86]Sr ratio of the Western Interior seaway was generally similar to contemporaneous oceans, although, periodically, the basin had strontium isotopic compositions distinct from contemporaneous seawater. 58 refs., 7 figs., 3 tabs.

  2. Neodymium glass laser with a pulse energy of 220 J and a pulse repetition rate of 0.02 Hz

    SciTech Connect

    Kuzmin, A A; Kulagin, O V; Khazanov, Efim A; Shaykin, A A

    2013-07-31

    A compact neodymium glass laser with a pulse energy of 220 J and a record-high pulse repetition rate of 0.02 Hz (pulse duration 30 ns) is developed. Thermally induced phase distortions are compensated using wave phase conjugation. The integral depolarisation of radiation is decreased to 0.4% by using linear compensation schemes. The second harmonic of laser radiation can be used for pumping Ti : sapphire multipetawatt complexes. (letters)

  3. Supported neodymium catalysts for isoprene and rac-β-butyrolactone polymerization: modulation of reactivity by controlled grafting.

    PubMed

    Terrier, Michael; Brulé, Emilie; Vitorino, Marta J; Ajellal, Noureddine; Robert, Carine; Gauvin, Régis M; Thomas, Christophe M

    2011-01-17

    A series of hybrid materials, bearing neodymium silylamide initiating groups, have been shown to mediate isoprene polymerization when combined with alkyl aluminum activators [methylaluminoxane, AlEt(2)Cl, Al(iBu)(3)]. The surface species nature and relative distribution were correlated with isoprene polymerization activity and selectivity. This approach to stereocontrol modulation has been extended to racemic β-butyrolactone isoselective ring opening polymerization.

  4. Impact of 3D Hierarchical Nanostructures on the Antibacterial Efficacy of a Bacteria-Triggered Self-Defensive Antibiotic Coating.

    PubMed

    Hizal, Ferdi; Zhuk, Iryna; Sukhishvili, Svetlana; Busscher, Henk J; van der Mei, Henny C; Choi, Chang-Hwan

    2015-09-16

    Titanium is often applied in implant surgery, but frequently implicated in infections associated with bacterial adhesion and growth on the implant surface. Here, we show that hierarchical nanostructuring of titanium and the subsequent coating of resulting topographical features with a self-defensive, antibacterial layer-by-layer (LbL) film enables a synergistic action of hierarchical nanotopography and localized, bacteria-triggered antibiotic release to dramatically enhance the antibacterial efficiency of surfaces. Although sole nanostructuring of titanium substrates did not significantly affect adhesion and growth of Staphylococcus aureus, the coating of 3D-nanopillared substrates with an ultrathin tannic acid/gentamicin (TA/G) LbL film resulted in a 10-fold reduction of the number of surface-attached bacteria. This effect is attributed to the enlarged surface area of the nanostructured coating available for localized bacteria-triggered release of antibiotics, as well as to the lower bacterial adhesion forces resulting in subsided activation of bacterial antibiotic-defense mechanisms when bacteria land on nanopillar tips. The result shows that a combination of 3D nanostructuring with a bacteria-triggered antibiotic-releasing coating presents a unique way to dramatically enhance antibacterial efficacy of biomaterial implants.

  5. Self assembled DC sputtered nanostructured rutile TiO₂ platform for bisphenol A detection.

    PubMed

    Singh, Nawab; Reza, K Kamil; Ali, Md Azahar; Agrawal, Ved Varun; Biradar, A M

    2015-06-15

    A novel biosensor platform comprising of the functionalized sputtered rutile nanostructured titanium dioxide (nTiO2) for rapid detection of estrogenic substance (bisphenol A) has been proposed. The direct current (DC) sputtering of titanium (Ti) on glass substrate has been converted to ordered nanostructured TiO2 film via oxidation. The nanostructured TiO2 surface was functionalized with self-assembled monolayer (SAM) of 3-aminopropyltriethoxysilane (APTES) and glutaraldehyde. The enzyme molecule, tyrosinase (Tyrs) has been covalently immobilized on the surface of APTES modified nanostructured TiO2 film. To investigate the crystalline structure and surface morphology of functionalized nTiO2/Ti electrode, the X-ray diffraction, scanning electron microscopy, atomic force microscopy and Fourier transform infrared spectroscopy have been carried out. This impedimetric biosensor exhibits a comparable sensitivity (361.9 kΩ/µM) in a wide range of detection (0.01-1.0 µM) and a response time of 250 s for bisphenol A (BPA) monitoring. This novel manufacturing process for nTiO2 film is cheap, practical and safer for functionalization with SAM and glutaraldehyde to improve the biosensor efficacy. The strong protein absorption capability of the nTiO2 surface demonstrates an excellent electrochemical biosensor and could be useful for the detection of other phenolic compounds.

  6. Cell response of anodized nanotubes on titanium and titanium alloys.

    PubMed

    Minagar, Sepideh; Wang, James; Berndt, Christopher C; Ivanova, Elena P; Wen, Cuie

    2013-09-01

    Titanium and titanium alloy implants that have been demonstrated to be more biocompatible than other metallic implant materials, such as Co-Cr alloys and stainless steels, must also be accepted by bone cells, bonding with and growing on them to prevent loosening. Highly ordered nanoporous arrays of titanium dioxide that form on titanium surface by anodic oxidation are receiving increasing research interest due to their effectiveness in promoting osseointegration. The response of bone cells to implant materials depends on the topography, physicochemistry, mechanics, and electronics of the implant surface and this influences cell behavior, such as adhesion, proliferation, shape, migration, survival, and differentiation; for example the existing anions on the surface of a titanium implant make it negative and this affects the interaction with negative fibronectin (FN). Although optimal nanosize of reproducible titania nanotubes has not been reported due to different protocols used in studies, cell response was more sensitive to titania nanotubes with nanometer diameter and interspace. By annealing, amorphous TiO2 nanotubes change to a crystalline form and become more hydrophilic, resulting in an encouraging effect on cell behavior. The crystalline size and thickness of the bone-like apatite that forms on the titania nanotubes after implantation are also affected by the diameter and shape. This review describes how changes in nanotube morphologies, such as the tube diameter, the thickness of the nanotube layer, and the crystalline structure, influence the response of cells.

  7. Multifunctional Ceramic Nanostructured Coatings

    DTIC Science & Technology

    2010-12-01

    silicon carbide composites // J. Europ. Cer. Soc. − 2004. − Vol. 24. − P. 2169−2179. 22. Yu. P. Udalov, E. E. Valova, S. S. Ordanian. Fabrication and...by the titanium and tungsten borides and carbides . The analysis was done using the X-ray and electron-optical methods. This information expands our...coating compositions should be based on limited solubility materials. Such systems include carbides , nitrides, borides and silicides based on

  8. Evaluating United States and world consumption of neodymium, dysprosium, terbium, and praseodymium in final products

    NASA Astrophysics Data System (ADS)

    Hart, Matthew

    This paper develops scenarios of future rare-earth-magnet metal (neodymium, dysprosium, terbium, and praseodymium) consumption in the permanent magnets used in wind turbines and hybrid electric vehicles. The scenarios start with naive base-case scenarios for growth in wind-turbine and hybrid-electric-vehicle sales over the period 2011 to 2020, using historical data for each good. These naive scenarios assume that future growth follows time trends in historical data and does not depend on any exogenous variable. Specifically, growth of each technological market follows historical time trends, and the amount of rare earths used per unit of technology remains fixed. The chosen reference year is 2010. Implied consumptions of the rare earth magnet metals are calculated from these scenarios. Assumptions are made for the material composition of permanent magnets, the market share of permanent-magnet wind turbines and vehicles, and magnet weight per unit of technology. Different scenarios estimate how changes in factors like the material composition of magnets, growth of the economy, and the price of a substitute could affect future consumption. Each scenario presents a different method for reducing rare earth consumption and could be interpreted as potential policy choices. In 2010, the consumption (metric tons, rare-earth-oxide equivalent) of each rare-earth-magnet metal was as follows. Total neodymium consumption in the world for both technologies was 995 tons; dysprosium consumption was 133 tons; terbium consumption was 50 tons; praseodymium consumption was zero tons. The base scenario for wind turbines shows there could be strong, exponential growth in the global wind turbine market. New U.S. sales of hybrid vehicles would decline (in line with the current economic recession) while non-U.S. sales increase through 2020. There would be an overall increase in the total amount of magnetic rare earths consumed in the world. Total consumption of each rare earth in the short

  9. Antibacterial Au nanostructured surfaces

    NASA Astrophysics Data System (ADS)

    Wu, Songmei; Zuber, Flavia; Brugger, Juergen; Maniura-Weber, Katharina; Ren, Qun

    2016-01-01

    We present here a technological platform for engineering Au nanotopographies by templated electrodeposition on antibacterial surfaces. Three different types of nanostructures were fabricated: nanopillars, nanorings and nanonuggets. The nanopillars are the basic structures and are 50 nm in diameter and 100 nm in height. Particular arrangement of the nanopillars in various geometries formed nanorings and nanonuggets. Flat surfaces, rough substrate surfaces, and various nanostructured surfaces were compared for their abilities to attach and kill bacterial cells. Methicillin-resistant Staphylococcus aureus, a Gram-positive bacterial strain responsible for many infections in health care system, was used as the model bacterial strain. It was found that all the Au nanostructures, regardless their shapes, exhibited similar excellent antibacterial properties. A comparison of live cells attached to nanotopographic surfaces showed that the number of live S. aureus cells was <1% of that from flat and rough reference surfaces. Our micro/nanofabrication process is a scalable approach based on cost-efficient self-organization and provides potential for further developing functional surfaces to study the behavior of microbes on nanoscale topographies.We present here a technological platform for engineering Au nanotopographies by templated electrodeposition on antibacterial surfaces. Three different types of nanostructures were fabricated: nanopillars, nanorings and nanonuggets. The nanopillars are the basic structures and are 50 nm in diameter and 100 nm in height. Particular arrangement of the nanopillars in various geometries formed nanorings and nanonuggets. Flat surfaces, rough substrate surfaces, and various nanostructured surfaces were compared for their abilities to attach and kill bacterial cells. Methicillin-resistant Staphylococcus aureus, a Gram-positive bacterial strain responsible for many infections in health care system, was used as the model bacterial strain. It

  10. TiO{sub 2} nanotube, nanowire, and rhomboid-shaped particle thin films fixed on a titanium metal plate

    SciTech Connect

    Inoue, Yuko; Noda, Iwao; Torikai, Toshio; Watari, Takanori; Hotokebuchi, Takao; Yada, Mitsunori

    2010-01-15

    Titanium dioxide thin films having various nanostructures could be formed by various treatments on sodium titanate nanotube thin films approximately 5 {mu}m thick fixed on titanium metal plates. Using an aqueous solution with a lower hydrochloric acid concentration (0.01 mol/L) and a higher reaction temperature (90 deg. C) than those previously employed, we obtained a hydrogen titanate nanotube thin film fixed onto a titanium metal plate by H{sup +} ion-exchange treatment of the sodium titanate nanotube thin film. Calcination of hydrogen titanate nanotube thin films yielded porous thin films consisting of anatase nanotubes, anatase nanowires, and anatase nanoparticles grown directly from the titanium metal plate. H{sup +} ion-exchange treatment of sodium titanate nanotube thin films at 140 deg. C resulted in porous thin films consisting of rhomboid-shaped anatase nanoparticles. - Graphical abstract: Titanium dioxide nanotube, nanowire, and rhombic particle thin films could be formed by various treatments on a sodium titanate nanotube thin film fixed on a titanium metal plate.

  11. The interplay between particulate and dissolved neodymium in the Western North Atlantic: First insights and interpretations

    NASA Astrophysics Data System (ADS)

    Stichel, T.; Kretschmer, S.; Lambelet, M.; van de Flierdt, T.; Rutgers van der Loeff, M.; Rijkenberg, M. J. A.; Gerringa, L. J.; De Baar, H. J. W.

    2014-12-01

    Dissolved neodymium (Nd) isotopes (expressed as ɛNd) have been widely used as a water mass tracer to reconstruct paleo ocean circulation. However, the marine geochemical cycle of Nd is not well understood. Unclear input mechanisms, scarcity of available data, and observed decoupling between dissolved ɛNd and Nd concentration patterns ([Nd]) are only a few of the unresolved issues. The latter is often referred to as the Nd paradox(e.g. Goldstein and Hemming 2003). Here we revisit this paradox with an unprecedented data set on particulate Nd isotope and concentration data from five stations along the Dutch GEOTRACES transect GA02 in the western North and equatorial Atlantic Ocean (cruises 64PE319 and 64PE321 from April to July 2010). Particulates were collected with in-situ pumps on 0.8 µm Supor filters and subjected to a total digestion procedure in the home laboratory. The particulates collected farthest north (Irminger Sea and Labrador Sea) show a strong affinity to the nearby land masses in their Nd isotope composition: Very negative values (ɛNd ≈-20) are observed in the Labrador Sea, which is surrounded by old continental rocks. More positive values of up to ɛNd ≈-4 are found east of Greenland probably derived from the Nansen Fjord Formation's basaltic rocks. In these two areas the particulate ɛNd is offset from dissolved Nd isotopes by up to 7.7 ɛ-units, but reveals a similar vertical distribution. Further downstream of the flow path of the North Atlantic Deep Water, dissolved and particulate Nd isotopic compositions in the water column seem to merge and become indistinguishable from one another south of Bermuda (BATS station). This seems to indicate that particulate and dissolved fractions exchange with increasing distance from source regions and age of water masses. Neodymium concentrations in particulates [pNd] are low (KD<5%) and invariant. However, most stations show a significant increase in [pNd] close to the seafloor, where [pNd] nearly

  12. Neodymium and strontium isotopic constraints on soil sources in Barbados, West Indies

    NASA Astrophysics Data System (ADS)

    Borg, Lars E.; Banner, Jay L.

    1996-11-01

    Neodymium and strontium isotopic compositions and Sm/Nd ratios are used to constrain the sources of silicate-rich soils developed on uplifted Pleistocene coral-reef limestones on Barbados, West Indies. The geographic and geologic setting of Barbados facilitates the application of these tracers to the evaluation of the following soil sources: (1) Pleistocene reef limestone regolith, (2) Tertiary carbonate rocks, sandstones, and mudstones that are exposed in northeastern Barbados, (3) volcanic ash erupted from the Lesser Antilles arc, (4) Saharan dust transported by trade winds, and (5) fertilizer. The soils have ɛNd values that range from -6.6 to -1.9, 87Sr /86Sr values of 0.70890 to 0.71067, and Sm/Nd ratios of 0.223-0.260. The Pleistocene limestone component is the most significant source of Sr in the soils and a negligible source of Nd. Comparison of Sm and Nd concentrations and neodymium isotopic compositions of soil samples that are weathered to varying extents indicates that Sm and Nd are relatively unfractionated and retained in the soils during weathering. ɛNd and Sm/Nd variations in the soils, therefore, primarily reflect the compositions and proportions of the silicate sources. Mass balance calculations based on SmNd systematics require that the silicate soil components contain between 30-85% volcanic ash, with the remaining silicate fraction comprised of old, continentally-derived sediment. In contrast to Sm and Nd, Sr is mobilized and removed from the soils during weathering. Strontium from volcanic and carbonate sources is preferentially removed relative to continental silicate sources. The strontium isotopic compositions of the soils, therefore, reflect the combined effects of the degree of weathering and the compositions and proportions of the soil sources. Mass balance calculations indicate that at least 35-60% of the initial Sr in the soils has been removed by weathering. These results illustrate (1) the utility of radiogenic isotopes in

  13. Titanium-based silicide quantum dot superlattices for thermoelectrics applications.

    PubMed

    Savelli, Guillaume; Stein, Sergio Silveira; Bernard-Granger, Guillaume; Faucherand, Pascal; Montès, Laurent; Dilhaire, Stefan; Pernot, Gilles

    2015-07-10

    Ti-based silicide quantum dot superlattices (QDSLs) are grown by reduced-pressure chemical vapor deposition. They are made of titanium-based silicide nanodots scattered in an n-doped SiGe matrix. This is the first time that such nanostructured materials have been grown in both monocrystalline and polycrystalline QDSLs. We studied their crystallographic structures and chemical properties, as well as the size and the density of the quantum dots. The thermoelectric properties of the QDSLs are measured and compared to equivalent SiGe thin films to evaluate the influence of the nanodots. Our studies revealed an increase in their thermoelectric properties-specifically, up to a trifold increase in the power factor, with a decrease in the thermal conductivity-making them very good candidates for further thermoelectric applications in cooling or energy-harvesting fields.

  14. Method for Surface Texturing Titanium Products

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A. (Inventor)

    1998-01-01

    The present invention teaches a method of producing a textured surface upon an arbitrarily configured titanium or titanium alloy object for the purpose of improving bonding between the object and other materials such as polymer matrix composites and/or human bone for the direct in-growth of orthopaedic implants. The titanium or titanium alloy object is placed in an electrolytic cell having an ultrasonically agitated solution of sodium chloride therein whereby a pattern of uniform "pock mark" like pores or cavities are produced upon the object's surface. The process is very cost effective compared to other methods of producing rough surfaces on titanium and titanium alloy components. The surface textures produced by the present invention are etched directly into the parent metal at discrete sites separated by areas unaffected by the etching process. Bonding materials to such surface textures on titanium or titanium alloy can thus support a shear load even if adhesion of the bonding material is poor.

  15. Titanium diaphragm makes excellent amplitron cathode support

    NASA Technical Reports Server (NTRS)

    Teich, W. W.

    1965-01-01

    Cathode support structure designed around a titanium diaphragm prevents radial misalignment between the cathode and anode in amplitrons. The titanium exhibits low thermal conductivity, tolerates lateral thermal expansion of the cathode, and is a poor primary and secondary emission medium.

  16. Titanium pigmentation. An electron probe microanalysis study

    SciTech Connect

    Dupre, A.; Touron, P.; Daste, J.; Lassere, J.; Bonafe, J.L.; Viraben, R.

    1985-05-01

    A patient had an unusual pigmentary disease induced by titanium dioxide. The use of a topical cream containing titanium dioxide caused a xanthomalike appearance on the patient's penis. Electron probe microanalysis was valuable in establishing the cause of this balanitis.

  17. An evaluation of the origin and post-depositional modification of coal mineral matter using rare earth elements and neodymium isotopes

    NASA Astrophysics Data System (ADS)

    Schatzel, Steven Joseph

    2001-07-01

    This study was conducted in western Pennsylvania on the Lower Kittanning Coal bed to address the issue of coal mineral matter origin and depositional environment. Channel samples of the coal, the underlying clay (paleosol) unit, and the overlying shale were retrieved over a 170 km east-west range of sampling sites. Analytical techniques applied to the samples include the megascopic description of coal lithotypes, proximate and ultimate analysis, inductively coupled plasma atomic emission spectroscopy (ICP-AES), coal petrography, instrumental neutron activation analysis (INAA), and thermal ionization mass spectrometry (TIMS). Major cation concentrations in the coal are generally consistent with depositional environment interpretations made on the overlying shale (e.g., epigenetic mineralization). Titanium and shale overburden-normalized plots of the major cation data show that the coal bed is enriched in Fe and Ca compared to the overlying shale. Magnesium, sodium and potassium were depleted in the coal relative to the shale. Rare earth element (REE) concentrations and neodymium (Nd) isotopes were used to identify sources of coal mineral matter and processes of alteration. A high degree of similarity exists between chondrite normalized REE plots of the coal, the shale overburden and the North American Shale Composite. The Nd isotopic data from the Lower Kittanning Coal bed show a range of epsilonNd(t) (at time of deposition) from -8.4 to -9.9 at the study sites. The Nd isotopic data from the overlying shale and the underlying clay unit show a range from epsilonNd(t) values = -8.2 to -10.2. These data are interpreted to indicate a single mineral source throughout the deposition of all three units. That source appears to be clastic matter derived the Appalachian Mountains. An isochron-style plot of the isotopic data appears to indicate Sm-Nd fractionation occurred at the approximate age of the coal bed. This is interpreted as evidence of mobilization of the Sm and Nd

  18. Effects of nanoporous anodic titanium oxide on human adipose derived stem cells.

    PubMed

    Malec, Katarzyna; Góralska, Joanna; Hubalewska-Mazgaj, Magdalena; Głowacz, Paulina; Jarosz, Magdalena; Brzewski, Pawel; Sulka, Grzegorz D; Jaskuła, Marian; Wybrańska, Iwona

    The aim of current bone biomaterials research is to design implants that induce controlled, guided, successful, and rapid healing. Titanium implants are widely used in dental, orthopedic, and reconstructive surgery. A series of studies has indicated that cells can respond not only to the chemical properties of the biomaterial, but also, in particular, to the changes in surface topography. Nanoporous materials remain in focus of scientific queries due to their exclusive properties and broad applications. One such material is nanostructured titanium oxide with highly ordered, mutually perpendicular nanopores. Nanoporous anodic titanium dioxide (TiO2) films were fabricated by a three-step anodization process in propan-1,2,3-triol-based electrolyte containing fluoride ions. Adipose-derived stem cells offer many interesting opportunities for regenerative medicine. The important goal of tissue engineering is to direct stem cell differentiation into a desired cell lineage. The influence of nanoporous TiO2 with pore diameters of 80 and 108 nm on cell response, growth, viability, and ability to differentiate into osteoblastic lineage of human adipose-derived progenitors was explored. Cells were harvested from the subcutaneous abdominal fat tissue by a simple, minimally invasive, and inexpensive method. Our results indicate that anodic nanostructured TiO2 is a safe and nontoxic biomaterial. In vitro studies demonstrated that the nanotopography induced and enhanced osteodifferentiation of human adipose-derived stem cells from the abdominal subcutaneous fat tissue.

  19. Effects of nanoporous anodic titanium oxide on human adipose derived stem cells

    PubMed Central

    Malec, Katarzyna; Góralska, Joanna; Hubalewska-Mazgaj, Magdalena; Głowacz, Paulina; Jarosz, Magdalena; Brzewski, Pawel; Sulka, Grzegorz D; Jaskuła, Marian; Wybrańska, Iwona

    2016-01-01

    The aim of current bone biomaterials research is to design implants that induce controlled, guided, successful, and rapid healing. Titanium implants are widely used in dental, orthopedic, and reconstructive surgery. A series of studies has indicated that cells can respond not only to the chemical properties of the biomaterial, but also, in particular, to the changes in surface topography. Nanoporous materials remain in focus of scientific queries due to their exclusive properties and broad applications. One such material is nanostructured titanium oxide with highly ordered, mutually perpendicular nanopores. Nanoporous anodic titanium dioxide (TiO2) films were fabricated by a three-step anodization process in propan-1,2,3-triol-based electrolyte containing fluoride ions. Adipose-derived stem cells offer many interesting opportunities for regenerative medicine. The important goal of tissue engineering is to direct stem cell differentiation into a desired cell lineage. The influence of nanoporous TiO2 with pore diameters of 80 and 108 nm on cell response, growth, viability, and ability to differentiate into osteoblastic lineage of human adipose-derived progenitors was explored. Cells were harvested from the subcutaneous abdominal fat tissue by a simple, minimally invasive, and inexpensive method. Our results indicate that anodic nanostructured TiO2 is a safe and nontoxic biomaterial. In vitro studies demonstrated that the nanotopography induced and enhanced osteodifferentiation of human adipose-derived stem cells from the abdominal subcutaneous fat tissue. PMID:27789947

  20. Electron-beam deposition of chromium carbide-based coatings with an ultradispersed structure or a nanostructure

    NASA Astrophysics Data System (ADS)

    Poletika, I. M.; Ivanov, S. F.; Gnyusov, S. F.; Perovskaya, M. V.

    2016-12-01

    Coatings with an ultradispersed structure and a nanostructure, which have a high wear resistance, corrosion resistance, and a satisfactory ductility, are fabricated by electron-beam vacuum-free deposition of a powder mixture of chromium carbide, chromium, and titanium carbide using a relativistic electron accelerator. The increase in the wear resistance and the ductility is shown to be associated with the modifying influence of titanium carbide, which manifests itself in sharp structure refinement the presence of numerous nucleation centers in it in the form of disperse TiC precipitates.

  1. Development of Lightweight Titanium Base Alloys

    DTIC Science & Technology

    1989-04-15

    program on Development of Lightweight Titanium Base Alloys was to develop new titanium alloys with 10% lower density, 50% higher elastic modulus, and...program. permitted the cvaluation of a low-dc-isity. dislicrsion-strengthcnicd 02 + y titanium aluminide , which has excellent high temperature strength...713e alloy has significantly higher strength than the titanium aluminides . The limited data for ’i-34AI-4Be show it to be very strong above 7(X)°C

  2. Process for reproducibly preparing titanium subhydride

    DOEpatents

    Carlson, Richard S.

    1982-01-01

    Titanium subhydride is produced in a reactor by heating a selected amount of finely divided titanium compound at a selected temperature for a selected period of time under dynamic vacuum conditions. Hydrogen is removed substantially uniformly from each powder grain and there is produced a subhydride of substantially uniform titanium-hydrogen composition. Selection of the amount, temperature and time produces a subhydride of selected titanium-hydrogen composition.

  3. Lightweight Protective Coatings For Titanium Alloys

    NASA Technical Reports Server (NTRS)

    Wiedemann, Karl E.; Taylor, Patrick J.; Clark, Ronald K.

    1992-01-01

    Lightweight coating developed to protect titanium and titanium aluminide alloys and titanium-matrix composite materials from attack by environment when used at high temperatures. Applied by sol-gel methods, and thickness less than 5 micrometers. Reaction-barrier and self-healing diffusion-barrier layers combine to protect titanium alloy against chemical attack by oxygen and nitrogen at high temperatures with very promising results. Can be extended to protection of other environmentally sensitive materials.

  4. Nanostructured Superhydrophobic Coatings

    SciTech Connect

    2009-03-01

    This factsheet describes a research project that deals with the nanostructured superhydrophobic (SH) powders developed at ORNL. This project seeks to (1) improve powder quality; (2) identify binders for plastics, fiberglass, metal (steel being the first priority), wood, and other products such as rubber and shingles; (3) test the coated product for coating quality and durability under operating conditions; and (4) application testing and production of powders in quantity.

  5. Planar plasmonic chiral nanostructures

    NASA Astrophysics Data System (ADS)

    Zu, Shuai; Bao, Yanjun; Fang, Zheyu

    2016-02-01

    A strong chiral optical response induced at a plasmonic Fano resonance in a planar Au heptamer nanostructure was experimentally and theoretically demonstrated. The scattering spectra show the characteristic narrow-band feature of Fano resonances for both left and right circular polarized lights, with a chiral response reaching 30% at the Fano resonance. Specifically, we systematically investigate the chiral response of planar heptamers with gradually changing the inter-particle rotation angles and separation distance. The chiral spectral characteristics clearly depend on the strength of Fano resonances and the associated near-field optical distributions. Finite element method simulations together with a multipole expansion method demonstrate that the enhanced chirality is caused by the excitation of magnetic quadrupolar and electric toroidal dipolar modes. Our work provides an effective method for the design of 2D nanostructures with a strong chiral response.A strong chiral optical response induced at a plasmonic Fano resonance in a planar Au heptamer nanostructure was experimentally and theoretically demonstrated. The scattering spectra show the characteristic narrow-band feature of Fano resonances for both left and right circular polarized lights, with a chiral response reaching 30% at the Fano resonance. Specifically, we systematically investigate the chiral response of planar heptamers with gradually changing the inter-particle rotation angles and separation distance. The chiral spectral characteristics clearly depend on the strength of Fano resonances and the associated near-field optical distributions. Finite element method simulations together with a multipole expansion method demonstrate that the enhanced chirality is caused by the excitation of magnetic quadrupolar and electric toroidal dipolar modes. Our work provides an effective method for the design of 2D nanostructures with a strong chiral response. Electronic supplementary information (ESI) available

  6. 21 CFR 73.3126 - Titanium dioxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Titanium dioxide. 73.3126 Section 73.3126 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3126 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide (CAS Reg. No. 13463-67-7), Color Index No. 77891,...

  7. 40 CFR 180.1195 - Titanium dioxide.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Titanium dioxide. 180.1195 Section 180.1195 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS... Titanium dioxide. Titanium dioxide is exempted from the requirement of a tolerance for residues in or...

  8. 21 CFR 73.575 - Titanium dioxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Titanium dioxide. 73.575 Section 73.575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.575 Titanium dioxide. (a) Identity. (1) The color additive titanium dioxide is synthetically prepared TiO2, free from admixture with other substances. (2)...

  9. 21 CFR 73.2575 - Titanium dioxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Titanium dioxide. 73.2575 Section 73.2575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2575 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide shall conform in identity and specifications to the...

  10. 21 CFR 73.1575 - Titanium dioxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Titanium dioxide. 73.1575 Section 73.1575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1575 Titanium dioxide. (a) Identity and specifications. (1) The color additive titanium dioxide shall conform in identity and specifications to the...

  11. 40 CFR 180.1195 - Titanium dioxide.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Titanium dioxide. 180.1195 Section 180.1195 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS... Titanium dioxide. Titanium dioxide is exempted from the requirement of a tolerance for residues in or...

  12. 21 CFR 73.1575 - Titanium dioxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Titanium dioxide. 73.1575 Section 73.1575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1575 Titanium dioxide. (a) Identity and specifications. (1) The color additive titanium dioxide shall conform in identity and specifications to the...

  13. 21 CFR 73.3126 - Titanium dioxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Titanium dioxide. 73.3126 Section 73.3126 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3126 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide (CAS Reg. No. 13463-67-7), Color Index No. 77891,...

  14. 21 CFR 73.2575 - Titanium dioxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Titanium dioxide. 73.2575 Section 73.2575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2575 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide shall conform in identity and specifications to the...

  15. 21 CFR 73.2575 - Titanium dioxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Titanium dioxide. 73.2575 Section 73.2575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2575 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide shall conform in identity and specifications to the...

  16. 21 CFR 73.2575 - Titanium dioxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Titanium dioxide. 73.2575 Section 73.2575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2575 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide shall conform in identity and specifications to the...

  17. 40 CFR 180.1195 - Titanium dioxide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Titanium dioxide. 180.1195 Section 180.1195 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS... Titanium dioxide. Titanium dioxide (CAS Reg. No. 13463-67-7) is exempted from the requirement of...

  18. 21 CFR 73.3126 - Titanium dioxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Titanium dioxide. 73.3126 Section 73.3126 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3126 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide (CAS Reg. No. 13463-67-7), Color Index No. 77891,...

  19. 21 CFR 73.1575 - Titanium dioxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Titanium dioxide. 73.1575 Section 73.1575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1575 Titanium dioxide. (a) Identity and specifications. (1) The color additive titanium dioxide shall conform in identity and specifications to the...

  20. 21 CFR 73.1575 - Titanium dioxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Titanium dioxide. 73.1575 Section 73.1575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1575 Titanium dioxide. (a) Identity and specifications. (1) The color additive titanium dioxide shall conform in identity and specifications to the...

  1. 21 CFR 73.2575 - Titanium dioxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Titanium dioxide. 73.2575 Section 73.2575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2575 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide shall conform in identity and specifications to the...

  2. 40 CFR 180.1195 - Titanium dioxide.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Titanium dioxide. 180.1195 Section 180.1195 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS... Titanium dioxide. Titanium dioxide is exempted from the requirement of a tolerance for residues in or...

  3. 21 CFR 73.1575 - Titanium dioxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Titanium dioxide. 73.1575 Section 73.1575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1575 Titanium dioxide. (a) Identity and specifications. (1) The color additive titanium dioxide shall conform in identity and specifications to the...

  4. 40 CFR 180.1195 - Titanium dioxide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Titanium dioxide. 180.1195 Section 180.1195 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS... Titanium dioxide. Titanium dioxide (CAS Reg. No. 13463-67-7) is exempted from the requirement of...

  5. Yttria Nanoparticle Reinforced Commercially Pure (CP) Titanium

    DTIC Science & Technology

    2011-09-01

    nanoparticles as well as titanium boride (TiB) reinforcements were produced through gas atomization. After consolidation and extrusion, room temperature...pure FE iron O oxygen Ti titanium TiB titanium boride TYS tensile yield strength UTS ultimate tensile strength wt% weight percent Y2O3

  6. Alternative nanostructures for thermophones.

    PubMed

    Aliev, Ali E; Mayo, Nathanael K; Jung de Andrade, Monica; Robles, Raquel O; Fang, Shaoli; Baughman, Ray H; Zhang, Mei; Chen, Yongsheng; Lee, Jae Ah; Kim, Seon Jeong

    2015-05-26

    Thermophones are highly promising for applications such as high-power SONAR arrays, flexible loudspeakers, and noise cancellation devices. So far, freestanding carbon nanotube aerogel sheets provide the most attractive performance as a thermoacoustic heat source. However, the limited accessibility of large-size freestanding carbon nanotube aerogel sheets and other even more exotic materials recently investigated hampers the field. We describe alternative materials for a thermoacoustic heat source with high-energy conversion efficiency, additional functionalities, environmentally friendly, and cost-effective production technologies. We discuss the thermoacoustic performance of alternative nanostructured materials and compare their spectral and power dependencies of sound pressure in air. We demonstrate that the heat capacity of aerogel-like nanostructures can be extracted by a thorough analysis of the sound pressure spectra. The study presented here focuses on engineering thermal gradients in the vicinity of nanostructures and subsequent heat dissipation processes from the interior of encapsulated thermoacoustic projectors. Applications of thermoacoustic projectors for high-power SONAR arrays, sound cancellation, and optimal thermal design, regarding enhanced energy conversion efficiency, are discussed.

  7. Plasmonic Nanostructured Cellular Automata

    NASA Astrophysics Data System (ADS)

    Alkhazraji, Emad; Ghalib, A.; Manzoor, K.; Alsunaidi, M. A.

    2017-03-01

    In this work, we have investigated the scattering plasmonic resonance characteristics of silver nanospheres with a geometrical distribution that is modelled by Cellular Automata using time-domain numerical analysis. Cellular Automata are discrete mathematical structures that model different natural phenomena. Two binary one-dimensional Cellular Automata rules are considered to model the nanostructure, namely rule 30 and rule 33. The analysis produces three-dimensional scattering profiles of the entire plasmonic nanostructure. For the Cellular Automaton rule 33, the introduction of more Cellular Automata generations resulted only in slight red and blue shifts in the plasmonic modes with respect to the first generation. On the other hand, while rule 30 introduced significant red shifts in the resonance peaks at early generations, at later generations however, a peculiar effect is witnessed in the scattering profile as new peaks emerge as a feature of the overall Cellular Automata structure rather than the sum of the smaller parts that compose it. We strongly believe that these features that emerge as a result adopting the different 256 Cellular Automata rules as configuration models of nanostructures in different applications and systems might possess a great potential in enhancing their capability, sensitivity, efficiency, and power utilization.

  8. Low Temperature Growth of Nanostructured Diamond Films on Metals

    NASA Technical Reports Server (NTRS)

    Baker, Paul A.; Catledge, Shane A.; Vohra, Yogesh K.

    2001-01-01

    The field of nanocrystalline diamond and tetrahedral amorphous carbon films has been the focus of intense experimental activity in the last few years for applications in field emission display devices, optical windows, and tribological coatings, The choice of substrate used in most studies has typically been silicon. For metals, however, the thermal expansion mismatch between the diamond film and substrate gives rise to thermal stress that often results in delamination of the film. To avoid this problem in conventional CVD deposition low substrate temperatures (less than 700 C) have been used, often with the incorporation of oxygen or carbon monoxide to the feedgas mixture. Conventionally grown CVD diamond films are also rough and would require post-deposition polishing for most applications. Therefore, there is an obvious need to develop techniques for deposition of well-adhered, smooth nano-structured diamond films on metals for various tribological applications. In our work, nanostructured diamond films are grown on a titanium alloy substrate using a two-step deposition process. The first step is performed at elevated temperature (820 C) for 30 minutes using a H2/CH4/N2 gas mixture in order to grow a thin (approx. 600 nm) nanostructured diamond layer and improve film adhesion. The remainder of the deposition involves growth at low temperature (less than 600 C) in a H2/CH4/O2 gas mixture. Laser reflectance Interferometry (LRI) pattern during growth of a nanostructured diamond film on Ti-6Al-4V alloy. The first 30 minutes are at a high temperature of 820 C and the rest of the film is grown at a low temperature of 580 T. The fringe pattern is observed till the very end due to extremely low surface roughness of 40 nm. The continuation of the smooth nanostructured diamond film growth during low temperature deposition is confirmed by in-situ laser reflectance interferometry and by post-deposition micro-Raman spectroscopy and surface profilometry. Similar experiments

  9. Photonuclear reactions on titanium isotopes

    SciTech Connect

    Belyshev, S. S.; Dzhilavyan, L. Z.; Ishkhanov, B. S.; Kapitonov, I. M.; Kuznetsov, A. A. Orlin, V. N.; Stopani, K. A.

    2015-03-15

    The photodisintegration of titanium isotopes in the giant-dipole-resonance energy region is studied by the photon-activation method. Bremsstrahlung photons whose spectrum has the endpoint energy of 55 MeV is used. The yields and integrated cross sections are determined for photoproton reactions on the titanium isotopes {sup 47,48,49,50}Ti. The respective experimental results are compared with their counterparts calculated on the basis of the TALYS code and a combined photonucleon-reaction model. The TALYS code disregards the isospin structure of the giant dipole resonance and is therefore unable to describe the yield of photoproton reactions on the heavy titanium isotopes {sup 49,50}Ti.

  10. Adaptive mesh refinement in titanium

    SciTech Connect

    Colella, Phillip; Wen, Tong

    2005-01-21

    In this paper, we evaluate Titanium's usability as a high-level parallel programming language through a case study, where we implement a subset of Chombo's functionality in Titanium. Chombo is a software package applying the Adaptive Mesh Refinement methodology to numerical Partial Differential Equations at the production level. In Chombo, the library approach is used to parallel programming (C++ and Fortran, with MPI), whereas Titanium is a Java dialect designed for high-performance scientific computing. The performance of our implementation is studied and compared with that of Chombo in solving Poisson's equation based on two grid configurations from a real application. Also provided are the counts of lines of code from both sides.

  11. Controlled implant/soft tissue interaction by nanoscale surface modifications of 3D porous titanium implants

    NASA Astrophysics Data System (ADS)

    Rieger, Elisabeth; Dupret-Bories, Agnès; Salou, Laetitia; Metz-Boutigue, Marie-Helene; Layrolle, Pierre; Debry, Christian; Lavalle, Philippe; Engin Vrana, Nihal

    2015-05-01

    Porous titanium implants are widely employed in the orthopaedics field to ensure good bone fixation. Recently, the use of porous titanium implants has also been investigated in artificial larynx development in a clinical setting. Such uses necessitate a better understanding of the interaction of soft tissues with porous titanium structures. Moreover, surface treatments of titanium have been generally evaluated in planar structures, while the porous titanium implants have complex 3 dimensional (3D) architectures. In this study, the determining factors for soft tissue integration of 3D porous titanium implants were investigated as a function of surface treatments via quantification of the interaction of serum proteins and cells with single titanium microbeads (300-500 μm in diameter). Samples were either acid etched or nanostructured by anodization. When the samples are used in 3D configuration (porous titanium discs of 2 mm thickness) in vivo (in subcutis of rats for 2 weeks), a better integration was observed for both anodized and acid etched samples compared to the non-treated implants. If the implants were also pre-treated with rat serum before implantation, the integration was further facilitated. In order to understand the underlying reasons for this effect, human fibroblast cell culture tests under several conditions (directly on beads, beads in suspension, beads encapsulated in gelatin hydrogels) were conducted to mimic the different interactions of cells with Ti implants in vivo. Physical characterization showed that surface treatments increased hydrophilicity, protein adsorption and roughness. Surface treatments also resulted in improved adsorption of serum albumin which in turn facilitated the adsorption of other proteins such as apolipoprotein as quantified by protein sequencing. The cellular response to the beads showed considerable difference with respect to the cell culture configuration. When the titanium microbeads were entrapped in cell

  12. Planar waveguides in neodymium-doped calcium niobium gallium garnet crystals produced by proton implantation

    NASA Astrophysics Data System (ADS)

    Chun-Xiao, Liu; Meng, Chen; Li-Li, Fu; Rui-Lin, Zheng; Hai-Tao, Guo; Zhi-Guang, Zhou; Wei-Nan, Li; She-Bao, Lin; Wei, Wei

    2016-04-01

    In this work, the fabrication and optical properties of a planar waveguide in a neodymium-doped calcium niobium gallium garnet (Nd:CNGG) crystal are reported. The waveguide is produced by proton (H+) implantation at 480 keV and a fluence of 1.0×1017 ions/cm2. The prism-coupling measurement is performed to obtain the dark mode of the waveguide at a wavelength of 632.8 nm. The reflectivity calculation method (RCM) is used to reconstruct the refractive index profile. The finite-difference beam propagation method (FD-BPM) is employed to calculate the guided mode profile of the waveguide. The stopping and range of ions in matter 2010 (SRIM 2010) code is used to simulate the damage profile induced by the ion implantation. The experimental and theoretical results indicate that the waveguide can confine the light propagation. Project supported by the National Natural Science Foundation of China (Grant Nos. 11405041, 61405240, 61077070, 61177086, 51002181, and 61177084), the Scientific Research Starting Foundation for New Teachers of Nanjing University of Posts and Telecommunications (NUPTSF) (Grant No. NY214159), and the Research Center of Optical Communications Engineering & Technology, Jiangsu Province, China (Grant No. ZSF0401).

  13. Laser treatment of a neodymium magnet and analysis of surface characteristics

    NASA Astrophysics Data System (ADS)

    Yilbas, B. S.; Ali, H.; Rizwan, M.; Kassas, M.

    2016-08-01

    Laser treatment of neodymium magnet (Nd2Fe14B) surface is carried out under the high pressure nitrogen assisting gas. A thin carbon film containing 12% WC carbide particles with 400 nm sizes are formed at the surface prior to the laser treatment process. Morphological and metallurgical changes in the laser treated layer are examined using the analytical tools. The corrosion resistance of the laser treated surface is analyzed incorporating the potentiodynamic tests carried out in 0.05 M NaCl+0.1 M H2SO4 solution. The friction coefficient of the laser treated surface is measured using the micro-scratch tester. The wetting characteristics of the treated surface are assessed incorporating the sessile water drop measurements. It is found that a dense layer consisting of fine size grains and WC particles is formed in the surface region of the laser treated layer. Corrosion resistance of the surface improves significantly after the laser treatment process. Friction coefficient of laser treated surface is lower than that of the as received surface. Laser treatment results in superhydrophobic characteristics at the substrate surface. The formation of hematite and grain size variation in the treated layer slightly lowers the magnetic strength of the laser treated workpiece.

  14. Efficient graphene Q switching and mode locking of 1.34 μm neodymium lasers.

    PubMed

    Xu, Jin-Long; Li, Xian-Lei; He, Jing-Liang; Hao, Xiao-Peng; Yang, Ying; Wu, Yong-Zhong; Liu, Shan-De; Zhang, Bai-Tao

    2012-07-01

    We demonstrate that few-layered graphene sheets used as a saturable absorber can provide efficient Q-switching and mode-locking modulation in 1.34 μm Nd:GdVO(4) bulk lasers. The minimum Q-switched pulses were 450 ns for 260 mW average power, 43 kHz repetition rate, and 2.5 μJ pulse energy. For the mode-locked laser, an average power of 1.29 W was achieved with 11 ps pulse duration and 13 nJ pulse energy. To our knowledge, this average power is the highest yet obtained from a graphene mode-locked laser, and the corresponding optical-optical efficiency of 23% is the best result among 1.3 μm neodymium mode-locked lasers. The quality factor M(2) of the Q-switched beam was 1.4 and 1.6 in the horizontal and longitudinal planes, respectively, and the M(2) of the mode-locked beam reached 1.1 and 1.0. These results clearly indicate the advantages of few-layered graphene as a saturable absorber.

  15. Near-infrared electroluminescence at room temperature from neodymium-doped gallium nitride thin films

    SciTech Connect

    Kim, Joo Han; Holloway, Paul H.

    2004-09-06

    Strong near-infrared (NIR) electroluminescence (EL) at room temperature from neodymium (Nd)-doped gallium nitride (GaN) thin films is reported. The Nd-doped GaN films were grown by radio-frequency planar magnetron cosputtering of separate GaN and metallic Nd targets in a pure nitrogen ambient. X-ray diffraction data did not identify the presence of any secondary phases and revealed that the Nd-doped GaN films had a highly textured wurtzite crystal structure with the c-axis normal to the surface of the film. The EL devices were fabricated with a thin-film multilayered structure of Al/Nd-doped GaN/Al{sub 2}O{sub 3}-TiO{sub 2}/indium-tin oxide and tested at room temperate. Three distinct NIR EL emission peaks were observed from the devices at 905, 1082, and 1364 nm, arising from the radiative relaxation of the {sup 4}F{sub 3sol2} excited-state energy level to the {sup 4}I{sub 9sol2}, {sup 4}I{sub 11sol2}, and {sup 4}I{sub 13sol2} levels of the Nd{sup 3+} ion, respectively. The threshold voltage for all the three emission peaks was {approx}150 V. The external power efficiency of the fabricated EL devices was {approx}1x10{sup -5} measured at 40 V above the threshold voltage.

  16. Mineralogy of the mid-ocean-ridge basalt source from neodymium isotopic composition of abyssal peridotites.

    PubMed

    Salters, Vincent J M; Dick, Henry J B

    2002-07-04

    Inferring the melting process at mid-ocean ridges, and the physical conditions under which melting takes place, usually relies on the assumption of compositional similarity between all mid-ocean-ridge basalt sources. Models of mantle melting therefore tend to be restricted to those that consider the presence of only one lithology in the mantle, peridotite. Evidence from xenoliths and peridotite massifs show that after peridotite, pyroxenite and eclogite are the most abundant rock types in the mantle. But at mid-ocean ridges, where most of the melting takes place, and in ophiolites, pyroxenite is rarely found. Here we present neodymium isotopic compositions of abyssal peridotites to investigate whether peridotite can indeed be the sole source for mid-ocean-ridge basalts. By comparing the isotopic compositions of basalts and peridotites at two segments of the southwest Indian ridge, we show that a component other than peridotite is required to explain the low end of the (143)Nd/(144)Nd variations of the basalts. This component is likely to have a lower melting temperature than peridotite, such as pyroxenite or eclogite, which could explain why it is not observed at mid-ocean ridges.

  17. Constraints on ocean circulation at the Paleocene-Eocene Thermal Maximum from neodymium isotopes

    NASA Astrophysics Data System (ADS)

    Abbott, April N.; Haley, Brian A.; Tripati, Aradhna K.; Frank, Martin

    2016-04-01

    Global warming during the Paleocene-Eocene Thermal Maximum (PETM) ˜ 55 million years ago (Ma) coincided with a massive release of carbon to the ocean-atmosphere system, as indicated by carbon isotopic data. Previous studies have argued for a role of changing ocean circulation, possibly as a trigger or response to climatic changes. We use neodymium (Nd) isotopic data to reconstruct short high-resolution records of deep-water circulation across the PETM. These records are derived by reductively leaching sediments from seven globally distributed sites to reconstruct past deep-ocean circulation across the PETM. The Nd data for the leachates are interpreted to be consistent with previous studies that have used fish teeth Nd isotopes and benthic foraminiferal δ13C to constrain regions of convection. There is some evidence from combining Nd isotope and δ13C records that the three major ocean basins may not have had substantial exchanges of deep waters. If the isotopic data are interpreted within this framework, then the observed pattern may be explained if the strength of overturning in each basin varied distinctly over the PETM, resulting in differences in deep-water aging gradients between basins. Results are consistent with published interpretations from proxy data and model simulations that suggest modulation of overturning circulation had an important role for initiation and recovery of the ocean-atmosphere system associated with the PETM.

  18. Neodymium(III) Complexes of Dialkylphosphoric and Dialkylphosphonic Acids Relevant to Liquid-Liquid Extraction Systems

    SciTech Connect

    Lumetta, Gregg J.; Sinkov, Sergey I.; Krause, Jeanette A.; Sweet, Lucas E.

    2016-01-27

    The complexes formed during the extraction of neodymium(III) into hydrophobic solvents containing acidic organophosphorus extractants were probed by single-crystal X-ray diffractometry, visible spectrophotometry, and Fourier-transform infrared spectroscopy. The crystal structure of the compound Nd(DMP)3 (1, DMP = dimethyl phosphate) revealed a polymeric arrangement in which each Nd(III) center is surrounded by six DMP oxygen atoms in a pseudo-octahedral environment. Adjacent Nd(III) ions are bridged by (MeO)2POO– anions, forming the polymeric network. The diffuse reflectance visible spectrum of 1 is nearly identical to that of the solid that is formed when an n-dodecane solution of di-(2-ethylhexyl)phosphoric acid (HA) is saturated with Nd(III), indicating a similar coordination environment around the Nd center in the NdA3 solid. The visible spectrum of the HA solution fully loaded with Nd(III) is very similar to that of the NdA3 material, both displaying hypersensitive bands characteristic of an pseudo-octahedral coordination environment around Nd. These spectral characteristics persisted across a wide range of organic Nd concentrations, suggesting that the pseudo-octahedral coordination environment is maintained from dilute to saturated conditions.

  19. Design and optimization of arrays of neodymium iron boron-based magnets for magnetic tweezers applications

    SciTech Connect

    Zacchia, Nicholas A.; Valentine, Megan T.

    2015-05-15

    We present the design methodology for arrays of neodymium iron boron (NdFeB)-based magnets for use in magnetic tweezers devices. Using finite element analysis (FEA), we optimized the geometry of the NdFeB magnet as well as the geometry of iron yokes designed to focus the magnetic fields toward the sample plane. Together, the magnets and yokes form a magnetic array which is the basis of the magnetic tweezers device. By systematically varying 15 distinct shape parameters, we determined those features that maximize the magnitude of the magnetic field gradient as well as the length scale over which the magnetic force operates. Additionally, we demonstrated that magnetic saturation of the yoke material leads to intrinsic limitations in any geometric design. Using this approach, we generated a compact and light-weight magnetic tweezers device that produces a high field gradient at the image plane in order to apply large forces to magnetic beads. We then fabricated the optimized yoke and validated the FEA by experimentally mapping the magnetic field of the device. The optimization data and iterative FEA approach outlined here will enable the streamlined design and construction of specialized instrumentation for force-sensitive microscopy.

  20. Interference of neodymium magnets with cardiac pacemakers and implantable cardioverter-defibrillators: an in vitro study.

    PubMed

    Ryf, Salome; Wolber, Thomas; Duru, Firat; Luechinger, Roger

    2008-01-01

    Permanent magnets may interfere with the function of cardiac pacemakers and implantable cardioverter-defibrillators (ICDs). Neodymium-iron-boron (NdFeB) magnets have become widely available in recent years and are incorporated in various articles of daily life. We conducted an in-vitro study to evaluate the ability of NdFeB magnets for home and office use to cause interference with cardiac pacemakers and ICDs. The magnetic fields of ten NdFeB magnets of different size and shape were measured at increasing distances beginning from the surface until a field-strength (B-field) value of 0.5 mT was reached. Furthermore, for each magnet the distance was determined at which a sample pacemaker switched from magnet mode to normal mode. Depending on the size and remanence of individual magnets, a B-field value of 0.5 mT was found at distances ranging from 1.5 cm to 30 cm and a value of 1 mT at distances from 1 cm to 22 cm. The pacemaker behavior was influenced at distances from 1 cm to 24 cm. NdFeB magnets for home and office use may cause interference with cardiac pacemakers and ICDs at distances up to 24 centimeters. Patient education and product declarations should include information about the risk associated with these magnets.

  1. Osmium and neodymium isotopic constraints on the temporal and spatial evolution of Siberian flood basalt sources

    USGS Publications Warehouse

    Horan, M.F.; Walker, R.J.; Fedorenko, V.A.; Czamanske, G.K.

    1995-01-01

    Picrites from the Gudchikhinsky suite, the oldest rocks examined, have ??Os of +5.3 to +6.1 and ??Nd of +3.7 to +4.0. The osmium and neodymium isotopic compositions of these rocks are similar to some modern ocean-island basalts (OIB), consistent with their derivation from an mantle plume. Picrites from the stratigraphically higher Tuklonsky suite have similar ??Os of +3.4 to +6.5, but ??Nd of -0.9 to -2.6. The similar ??Os, but lower ??Nd , suggest that some magmas from the same OIB-type, mantle source were contaminated by lithospheric components. A differentiated ankaramite flow, associated with the top of the stratigraphically higher Morongovsky suite, has ??Os of +9.8 to +10.2 and ??Nd of +1.3 to +1.4. The higher ??Os may indicate that the plume source was heterogeneous with respect to osmium isotopic composition, consistent with osmium isotopic measurements in rocks from other plume sources. Mg-rich, alkaline rocks (meymechites) from the Guli area that erupted much nearer the end of the flood-basalt event have ??Os of -1.2 to -2.6 and ??Nd of +3.7 to +4.9. These rocks were probably produced by low degrees of partial melting of mantle after the main stages of flood-basalt production. -from Authors

  2. Rhenium-osmium and samarium-neodymium isotopic systematics of the stillwater complex

    USGS Publications Warehouse

    Lambert, D.D.; Morgan, J.W.; Walker, R.J.; Shirey, S.B.; Carlson, R.W.; Zientek, M.L.; Koski, M.S.

    1989-01-01

    Isotopic data for the Stillwater Complex, Montana , which formed about 2700 Ma (million years ago), were obtained to evaluate the role of magma mixing in the formation of strategic platinum-group element (PGE) ore deposits. Neodymium and osmium isotopic data indicate that the intrusion formed from at least two geochemically distinct magmas. Ultramafic affinity (U-type) magmas had initial ??Nd of -0.8 to -3.2 and a chondritic initial 187Os/186Os ratio of ???0.88, whereas anorthositic affinity (A-type) magmas had ??Nd of -0.7 to +1.7 and an initial 187Os/186Os ratio of ???1.13. These data suggest that U-type magmas were derived from a lithospheric mantle source containing recycled crustal materials whereas A-type magmas originated either by crustal contamination of basaltic magmas or by partial melting of basalt in the lower crust. The Nd and Os isotopic data also suggest that Os, and probably the other PGEs in ore horizons such as the J-M Reef, was derived from A-type magmas. The Nd and Os isotopic heterogeneity observed in rocks below the J-M Reef also suggests that A-type magmas were injected into the Stillwater U-type magma chamber at several stages during the development of the Ultramafic series.

  3. Spectroscopic characterization of alkali modified zinc-tellurite glasses doped with neodymium.

    PubMed

    Rajeswari, R; Babu, S Surendra; Jayasankar, C K

    2010-09-15

    Neodymium doped zinc-tellurite glasses of composition TeO(2)-ZnO-Na(2)O-Li(2)O have been prepared and characterized for their thermal, structural and optical properties. Differential thermal analysis revealed reasonably good forming tendency of the glass composition. FTIR spectra were used to analyze the functional groups present in the glass. Judd-Ofelt intensity parameters were derived from the absorption spectrum and used to calculate the radiative lifetime, branching ratio and stimulated emission cross-section for (4)F(3/2)-->(4)I(9/2, 11/2, 13/2) transitions. The quantum efficiency of the (4)F(3/2) level is comparable to the typical values obtained for the Nd(2)O(3)-doped glasses. The decay properties for higher concentration of Nd(2)O(3) were analyzed using Inokuti-Hirayama model to investigate the non-radiative relaxation of the (4)F(3/2) emitting level. The experimental values of branching ratio and saturation intensity of (4)F(3/2)-->(4)I(11/2) transition and calculated spectroscopic quality factor indicate the favourable lasing action in these glasses.

  4. Analysis of a 10 megawatt space-based solar-pumped neodymium laser system

    NASA Technical Reports Server (NTRS)

    Kurweg, U. H.

    1984-01-01

    A ten megawatt solar-pumped continuous liquid laser system for space applications is examined. It is found that a single inflatable mirror of 434 m diameter used in conjunction with a conical secondary concentrator is sufficient to side pump a liquid neodymium lasant in an annular tube of 6 m length and 1 m outer and 0.8 m inner diameter. About one fourth of intercepted radiation converging on the laser tube is absorbed and one fifth of this radiation is effective in populating the upper levels. The liquid lasant is flowed through the annular laser cavity at 1.9 m/s and is cooled via a heat exchanger and a large radiator surface comparable in size to the concentrating mirror. The power density of incident light within the lasant of approximately 68 watt/cu cm required for cw operation is exceeded in the present annular configuration. Total system weight corresponds to 20,500 kg and is thus capable of being transported to near Earth orbit by a single shuttle flight.

  5. Power scaling of diode-pumped neodymium yttrium aluminum borate laser

    NASA Technical Reports Server (NTRS)

    Hemmati, Hamid

    1991-01-01

    Preliminary results are presented of the efficient diode-pumped operation of a neodymium yttrium aluminum borate (NYAB) laser at 531.5 nm using two 1-W diode-laser arrays for the pump. With 1380 mW of CW power incident on the crystal, as much as 51 mW of 532.5-nm laser radiation was obtained with the unoptimized cavity. The corresponding optical-to-optical conversion efficiency was 3.7 percent. A plot of the output 531.5 nm vs incident 807 nm pump power is shown. The crystal output power was critically dependent on the rotational and translational adjustment of the NYAB crystal inside the cavity. It is suggested that a crystal cut at the exact phase matching angle, placed in a cavity with proper optimal reflection and transmission mirror coatings, and pumped at proper wavelength can result in higher output power. Thus, the NYAB output power approaches that of a CW intracavity frequency doubled Nd:YAG laser.

  6. High-mobility thin film transistors with neodymium-substituted indium oxide active layer

    SciTech Connect

    Lin, Zhenguo; Lan, Linfeng Xiao, Peng; Sun, Sheng; Li, Yuzhi; Song, Wei; Gao, Peixiong; Wang, Lei; Ning, Honglong; Peng, Junbiao

    2015-09-14

    Thin-film transistors (TFTs) with neodymium-substituted indium oxide (InNdO) channel layer were demonstrated. The structural properties of the InNdO films as a function of annealing temperature have been analyzed using X-ray diffraction and transmission electron microscopy. The InNdO thin films showed polycrystalline nature when annealed at 450 °C with a lattice parameter (cubic cell) of 10.255 Å, which is larger than the cubic In{sub 2}O{sub 3} film (10.117 Å). The high-resolution transmission electron microscopy and energy dispersive X-ray spectroscopy showed that no Nd{sub 2}O{sub 3} clusters were found in the InNdO film, implying that Nd was incorporated into the In{sub 2}O{sub 3} lattice. The InNdO TFTs annealed at 450 °C exhibited more excellent electrical properties with a high mobility of 20.4 cm{sup 2} V{sup −1} s{sup −1} and better electric bias stability compared to those annealed at 300 °C, which was attributed to the reduction of the scattering centers and/or charge traps due to the decrease of the |Nd3d{sub 5/2}{sup 5}4f{sup 4}O2p{sup −1}〉 electron configuration.

  7. Highly efficient neodymium:yttrium aluminum garnet laser end pumped by a semiconductor laser array

    NASA Technical Reports Server (NTRS)

    Sipes, D. L.

    1985-01-01

    In recent experiments, 80-mW CW power in a single mode has been achieved from a neodymium:yttrium aluminum garnet (Nd:YAG) laser with only 1 W of electrical power input to a single semiconductor laser array pump. This corresponds to an overall efficiency of 8 percent, the highest reported CW efficiency for a Nd:YAG laser. A tightly focused semiconductor laser end pump configuration is used to achieve high pumping intensities (on the order of 1 kW/sq cm), which in turn causes the photon to photon conversion efficiency to approach the quantum efficiency (76 percent for Nd:YAG at 1.06 microns pumped at 0.810 micron). This is achieved despite the dual-lobed nature of the pump. Through the use of simple beam-combining schemes (e.g., polarization coupling and multireflection point pumping), output powers over 1 W and overall electrical to optical efficiencies as high as 10 percent are expected.

  8. Bleb reduction using combined photodisruptive and photocoagulative neodymium-doped yttrium-aluminum-garnet laser

    PubMed Central

    Kumar, Harsh; Dangda, Sonal

    2016-01-01

    This case report aims to highlight the role of photodisruptive neodymium-doped yttrium-aluminum-garnet (Nd:YAG) (1064 nm) laser in the treatment of bleb dysesthesia, which occurs in overhanging blebs or with perilimbal spread. Although treatment of such dysesthetic blebs with laser photocoagulation has been previously described, cases where the height of bleb precludes laser penetration, desired effect might not be seen. We herein describe a technique using a combination of photocoagulative (532 nm) and photodisruptive (1064 nm) Nd:YAG laser for a high bleb migrating nasally and inferiorly along the limbus in a 64-year-old female, causing hypotony and consequent macular edema. Successful reduction could be achieved within a week of treatment. By 6 weeks, intraocular pressure improved to 8 mmHg, macular edema subsided, and visual acuity improved to 6/6. Although surgical procedures to correct bleb dysesthesia are available, laser procedures being quick outpatient modalities are more comfortable for the patients. PMID:28112138

  9. Neodymium doped fluoroindogallate glasses as highly-sensitive luminescent non-contact thermometers

    NASA Astrophysics Data System (ADS)

    Nunes, Luiz A. O.; Souza, Adelmo S.; Carlos, Luís D.; Malta, Oscar L.

    2017-01-01

    Trivalent neodymium (Nd3+) can be used as high performance temperature luminescent ion sensor, namely in the near infrared spectral region. The disadvantage presented in the use of this ion is that transitions from thermally coupled levels show very different emission intensities. In order to solve this critical problem we propose to use Nd3+-doped fluoroindogallate glasses with low phonon cutoff energy (500 cm-1) as the active medium. By using a dopant concentration that minimizes losses due to cross relaxation processes and detecting the emissions of the thermally coupled levels with a R928 photomultiplier, without correction response for the wavelength dependence of the intensity, we have succeeded in getting the highest relative thermal sensitivities so far observed, 2.5%ṡK-1 and 7.4%ṡK-1, for the 4F5/2 → 4I9/2/4F3/2 → 4I9/2 and 4F7/2 → 4I9/2/4F3/2 → 4I9/2 intensity ratios, respectively at 288 K.

  10. Design and optimization of arrays of neodymium iron boron-based magnets for magnetic tweezers applications

    NASA Astrophysics Data System (ADS)

    Zacchia, Nicholas A.; Valentine, Megan T.

    2015-05-01

    We present the design methodology for arrays of neodymium iron boron (NdFeB)-based magnets for use in magnetic tweezers devices. Using finite element analysis (FEA), we optimized the geometry of the NdFeB magnet as well as the geometry of iron yokes designed to focus the magnetic fields toward the sample plane. Together, the magnets and yokes form a magnetic array which is the basis of the magnetic tweezers device. By systematically varying 15 distinct shape parameters, we determined those features that maximize the magnitude of the magnetic field gradient as well as the length scale over which the magnetic force operates. Additionally, we demonstrated that magnetic saturation of the yoke material leads to intrinsic limitations in any geometric design. Using this approach, we generated a compact and light-weight magnetic tweezers device that produces a high field gradient at the image plane in order to apply large forces to magnetic beads. We then fabricated the optimized yoke and validated the FEA by experimentally mapping the magnetic field of the device. The optimization data and iterative FEA approach outlined here will enable the streamlined design and construction of specialized instrumentation for force-sensitive microscopy.

  11. PENTAMETHYLCYCLOPENTADIENYL DERIVATIVES OF THE TRIVALENT LANTHANIDE ELEMENTS (NEODYMIUM, SAMARIUM, AND YTTERBIUM)

    SciTech Connect

    Tilley, T. Don; Andersen, R.A.

    1980-07-01

    The anionic complexes of the type (ML{sub x})(Me{sub 5}C{sub 5}){sub 2}M'Cl{sub 2}, where M is lithium or sodium, L is diethyl ether or N,N,-N{prime},N{prime}-tetramethylethylenediamine, and M{prime} is neodymium, samarium, or ytterbium, have been prepared from the metal trichlorides and the pentamethylcyclopentadienide anion. The neutral species (Me{sub 5}C{sub 5}){sub 2}NdCl(THF), (Me{sub 5}C{sub 5}){sub 2}NdN(SiMe{sub 3}){sub 2}, and (Me{sub 5}C{sub 5}){sub 2}YbCl(THF) have also been prepared. The mono-ring derivatives (Na(OEt{sub 2}){sub 2})((C{sub 5}Me{sub 5})NdCl{sub 3}) and (Me{sub 5}C{sub 5})Nd(N(SiMe{sub 3}){sub 2}){sub 2} are also described.

  12. Optical constants determination of neodymium and gadolinium in the 3-nm to 100-nm wavelength range

    NASA Astrophysics Data System (ADS)

    Kjornrattanawanich, B.; Windt, D. L.; Uspenskii, Y. A.; Seely, J. F.

    2006-08-01

    The optical constants (n, k) of the wavelength-dependent index of refraction N = n+ik = 1-δ+ik of Nd (Neodymium) and Gd (Gadolinium) are determined in the wavelength range of 3 nm to 100 nm by the transmittance method using synchrotron radiation. Nd and Gd films with thicknesses ranging from 5 nm to 180 nm were fabricated on Si photodiodes (which served as the coating substrates as well as the detectors) and capped with Si layers to protect these reactive rare earth elements from oxidation. The imaginary part (k) obtained directly from the transmittance measurement is used in the derivation of the real part (δ) of the complex index of refraction N through the Kramers- Kronig integral. The measured optical constants are used in the design of currently developed Nd- and Gd-based multilayers for solar imaging applications. Our results on Nd and Gd optical constants and the reflectance of some Nd- and Gd-based multilayers are presented.

  13. Rapid neodymium release to marine waters from lithogenic sediments in the Amazon estuary

    PubMed Central

    Rousseau, Tristan C. C.; Sonke, Jeroen E.; Chmeleff, Jérôme; van Beek, Pieter; Souhaut, Marc; Boaventura, Geraldo; Seyler, Patrick; Jeandel, Catherine

    2015-01-01

    Rare earth element (REE) concentrations and neodymium isotopic composition (ɛNd) are tracers for ocean circulation and biogeochemistry. Although models suggest that REE release from lithogenic sediment in river discharge may dominate all other REE inputs to the oceans, the occurrence, mechanisms and magnitude of such a source are still debated. Here we present the first simultaneous observations of dissolved (<0.45 μm), colloidal and particulate REE and ɛNd in the Amazon estuary. A sharp drop in dissolved REE in the low-salinity zone is driven by coagulation of colloidal matter. At mid-salinities, total dissolved REE levels slightly increase, while ɛNd values are shifted from the dissolved Nd river endmember (−8.9) to values typical of river suspended matter (−10.6). Combining a Nd isotope mass balance with apparent radium isotope ages of estuarine waters suggests a rapid (3 weeks) and globally significant Nd release by dissolution of lithogenic suspended sediments. PMID:26158849

  14. Application of neodymium isotope ratio measurements for the origin assessment of uranium ore concentrates.

    PubMed

    Krajkó, Judit; Varga, Zsolt; Yalcintas, Ezgi; Wallenius, Maria; Mayer, Klaus

    2014-11-01

    A novel procedure has been developed for the measurement of (143)Nd/(144)Nd isotope ratio in various uranium-bearing materials, such as uranium ores and ore concentrates (UOC) in order to evaluate the usefulness and applicability of variations of (143)Nd/(144)Nd isotope ratio for provenance assessment in nuclear forensics. Neodymium was separated and pre-concentrated by extraction chromatography and then the isotope ratios were measured by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). The method was validated by the measurement of standard reference materials (La Jolla, JB-2 and BCR-2) and the applicability of the procedure was demonstrated by the analysis of uranium samples of world-wide origin. The investigated samples show distinct (143)Nd/(144)Nd ratio depending on the ore type, deposit age and Sm/Nd ratio. Together with other characteristics of the material in question, the Nd isotope ratio is a promising signature for nuclear forensics and suggests being indicative of the source material, the uranium ore.

  15. Thermal Stir Welds in Titanium

    NASA Astrophysics Data System (ADS)

    Fonda, Richard W.; Knipling, Keith E.; Pilchak, Adam L.

    2016-01-01

    Although conventional friction stir welding (FSW) has proven unsuccessful in joining thick sections of alpha and near-alpha titanium alloys, thermal stir welding, a variant of the FSW process in which an external heat source is used to preheat the workpiece, is demonstrated to be able to reliably join 12.3-mm-thick plates of CP titanium. This paper describes the microstructures and textures that develop in these thermal stir welds. The observed microstructure was used to reconstruct the high-temperature microstructure and texture present during the welding process and therefore reveal the genesis of the welding structures.

  16. Sensitization of neodymium ion luminescence by chromium ions in a Gd/sub 3/Ga/sub 5/O/sub 12/ crystal

    SciTech Connect

    Zharikov, E.V.; Il'ichev, N.N.; Laptev, V.V.; Malyutin, A.A.; Ostroumov, V.G.; Pashinin, P.P.; Shcherbakov, I.A.

    1982-03-01

    An investigation is reported of the spectral, luminescence, and lasing properties of a Gd/sub 3/Ga/sub 5/O/sub 12/ crystal activated with chromium and neodymium ions. The high efficiency of the energy transfer process from chromium to neodymium ions is demonstrated. For example, the probability of an elementary Cr/sup 3 +/--Nd/sup 3 +/ interaction event in a Gd/sub 3/Ga/sub 5/O/sub 12/ crystal was 12 times higher than that in a Y/sub 3/Al/sub 5/O/sub 12/ crystal. It was found that sensitization of neodymium ion luminescence by chromium ions can increase severalfold the energy characteristics of cw and pulsed neodymium lasers. An investigation of the free-lasing parameters shows that the ultimate differential lasing efficiency of neodymium in a Gd/sub 3/Ga/sub 5/O/sub 12/:Cr:Nd crystal is 3.6 times higher than that for a YAG:Nd crystal under comparable conditions.

  17. Effect of whitening toothpaste on titanium and titanium alloy surfaces.

    PubMed

    Faria, Adriana Cláudia Lapria; Bordin, Angelo Rafael de Vito; Pedrazzi, Vinícius; Rodrigues, Renata Cristina Silveira; Ribeiro, Ricardo Faria

    2012-01-01

    Dental implants have increased the use of titanium and titanium alloys in prosthetic applications. Whitening toothpastes with peroxides are available for patients with high aesthetic requirements, but the effect of whitening toothpastes on titanium surfaces is not yet known, although titanium is prone to fluoride ion attack. Thus, the aim of the present study was to compare Ti-5Ta alloy to cp Ti after toothbrushing with whitening and conventional toothpastes. Ti-5Ta (%wt) alloy was melted in an arc melting furnace and compared with cp Ti. Disks and toothbrush heads were embedded in PVC rings to be mounted onto a toothbrushing test apparatus. A total of 260,000 cycles were carried out at 250 cycles/minute under a load of 5 N on samples immersed in toothpaste slurries. Surface roughness and Vickers microhardness were evaluated before and after toothbrushing. One sample of each material/toothpaste was analyzed by Scanning Electron Microscopy (SEM) and compared with a sample that had not been submitted to toothbrushing. Surface roughness increased significantly after toothbrushing, but no differences were noted after toothbrushing with different toothpastes. Toothbrushing did not significantly affect sample microhardness. The results suggest that toothpastes that contain and those that do not contain peroxides in their composition have different effects on cp Ti and Ti-5Ta surfaces. Although no significant difference was noted in the microhardness and roughness of the surfaces brushed with different toothpastes, both toothpastes increased roughness after toothbrushing.

  18. Research and Development on Titanium Alloys

    DTIC Science & Technology

    1949-10-31

    svmym lIfe. Th~e rAnge of cOmposila Ivwstpted in the bin"rtniaum-stiver sistems was extended to 5% snw an M~an~Ajmm loy cntprn 0.1 Is beryllium were...extended to 5,0 per cent silverl and titanium- beryllium alloys containing 0.1 to-1.0 per cent berylliuma were inveitiga~ted. None of~ these alloys had...of: 1. Binary titanium-germanium alloys. 2. Binary titanium-nickel alloys. 3, Binary titanium-silver alloys. 4. Binary titanium- beryllium alloys. 5

  19. Method of making multilayered titanium ceramic composites

    DOEpatents

    Fisher, II, George T.; Hansen, Jeffrey S.; Oden, Laurance L.; Turner, Paul C.; Ochs, Thomas L.

    1998-01-01

    A method making a titanium ceramic composite involves forming a hot pressed powder body having a microstructure comprising at least one titanium metal or alloy layer and at least one ceramic particulate reinforced titanium metal or alloy layer and hot forging the hot pressed body follwed by hot rolling to substantially reduce a thickness dimension and substantially increase a lateral dimension thereof to form a composite plate or sheet that retains in the microstructure at least one titanium based layer and at least one ceramic reinforced titanium based layer in the thickness direction of the composite plate or sheet.

  20. Method of making multilayered titanium ceramic composites

    DOEpatents

    Fisher, G.T. II; Hansen, J.S.; Oden, L.L.; Turner, P.C.; Ochs, T.L.

    1998-08-25

    A method making a titanium ceramic composite involves forming a hot pressed powder body having a microstructure comprising at least one titanium metal or alloy layer and at least one ceramic particulate reinforced titanium metal or alloy layer and hot forging the hot pressed body followed by hot rolling to substantially reduce a thickness dimension and substantially increase a lateral dimension thereof to form a composite plate or sheet that retains in the microstructure at least one titanium based layer and at least one ceramic reinforced titanium based layer in the thickness direction of the composite plate or sheet. 3 figs.

  1. Method of making multilayered titanium ceramic composites

    DOEpatents

    Fisher, George T., II; Hansen; Jeffrey S.; Oden; Laurance L.; Turner; Paul C.; Ochs; Thomas L.

    1998-08-25

    A method making a titanium ceramic composite involves forming a hot pressed powder body having a microstructure comprising at least one titanium metal or alloy layer and at least one ceramic particulate reinforced titanium metal or alloy layer and hot forging the hot pressed body follwed by hot rolling to substantially reduce a thickness dimension and substantially increase a lateral dimension thereof to form a composite plate or sheet that retains in the microstructure at least one titanium based layer and at least one ceramic reinforced titanium based layer in the thickness direction of the composite plate or sheet.

  2. Spark plasma sintering synthesis of porous nanocrystalline titanium alloys for biomedical applications.

    PubMed

    Nicula, R; Lüthen, F; Stir, M; Nebe, B; Burkel, E

    2007-11-01

    The reason for the extended use of titanium and its alloys as implant biomaterials stems from their lower elastic modulus, their superior biocompatibility and improved corrosion resistance compared to the more conventional stainless steel and cobalt-based alloys [Niinomi, M., Hattori, T., Niwa, S., 2004. Material characteristics and biocompatibility of low rigidity titanium alloys for biomedical applications. In: Jaszemski, M.J., Trantolo, D.J., Lewandrowski, K.U., Hasirci, V., Altobelli, D.E., Wise, D.L. (Eds.), Biomaterials in Orthopedics. Marcel Dekker Inc., New York, pp. 41-62]. Nanostructured titanium-based biomaterials with tailored porosity are important for cell-adhesion, viability, differentiation and growth. Newer technologies like foaming or low-density core processing were recently used for the surface modification of titanium alloy implant bodies to stimulate bone in-growth and improve osseointegration and cell-adhesion, which in turn play a key role in the acceptance of the implants. We here report preliminary results concerning the synthesis of mesoporous titanium alloy bodies by spark plasma sintering. Nanocrystalline cp Ti, Ti-6Al-4V, Ti-Al-V-Cr and Ti-Mn-V-Cr-Al alloy powders were prepared by high-energy wet-milling and sintered to either full-density (cp Ti, Ti-Al-V) or uniform porous (Ti-Al-V-Cr, Ti-Mn-V-Cr-Al) bulk specimens by field-assisted spark plasma sintering (FAST/SPS). Cellular interactions with the porous titanium alloy surfaces were tested with osteoblast-like human MG-63 cells. Cell morphology was investigated by scanning electron microscopy (SEM). The SEM analysis results were correlated with the alloy chemistry and the topographic features of the surface, namely porosity and roughness.

  3. Microstructured silicon created with a nanosecond neodymium-doped yttrium aluminum garnet laser

    NASA Astrophysics Data System (ADS)

    Mandeville, W. J.; Shaffer, M. K.; Lu, Yalin; O'Keefe, D.; Knize, R. J.

    2011-08-01

    We produce microstructured silicon using frequency doubled, nanosecond Nd:YAG pulses in SF6 gas. The micro-penitentes formed are up to 20 μm tall with a sulfur concentration of 0.5% near the surface. The infrared absorption is increased to near unity and extends well below the original bandgap far into the infrared. These data are similar to results reported by others using more complicated and less economical femtosecond titanium sapphire and picosecond and nanosecond excimer lasers.

  4. Design of nanostructured-based glucose biosensors

    NASA Astrophysics Data System (ADS)

    Komirisetty, Archana; Williams, Frances; Pradhan, Aswini; Konda, Rajini B.; Dondapati, Hareesh; Samantaray, Diptirani

    2012-04-01

    This paper presents the design of glucose sensors that will be integrated with advanced nano-materials, bio-coatings and electronics to create novel devices that are highly sensitive, inexpensive, accurate, and reliable. In the work presented, a glucose biosensor and its fabrication process flow have been designed. The device is based on electrochemical sensing using a working electrode with bio-functionalized zinc oxide (ZnO) nano-rods. Among all metal oxide nanostructures, ZnO nano-materials play a significant role as a sensing element in biosensors due to their properties such as high isoelectric point (IEP), fast electron transfer, non-toxicity, biocompatibility, and chemical stability which are very crucial parameters to achieve high sensitivity. Amperometric enzyme electrodes based on glucose oxidase (GOx) are used due to their stability and high selectivity to glucose. The device also consists of silicon dioxide and titanium layers as well as platinum working and counter electrodes and a silver/silver chloride reference electrode. Currently, the biosensors are being fabricated using the process flow developed. Once completed, the sensors will be bio-functionalized and tested to characterize their performance, including their sensitivity and stability.

  5. Synthesis and properties of nanoscale titanium boride

    NASA Astrophysics Data System (ADS)

    Efimova, K. A.; Galevskiy, G. V.; Rudneva, V. V.

    2015-09-01

    This work reports the scientific and technological grounds for plasma synthesis of titanium diboride, including thermodynamic and kinetic conditions of boride formation when titanium and titanium dioxide are interacting with products resulting from boron gasification in the nitrogen - hydrogen plasma flow, and two variations of its behavior using the powder mixtures: titanium - boron and titanium dioxide - boron. To study these technology variations, the mathematical models were derived, describing the relation between element contents in the synthesized products of titanium and free boron and basic parameters. The probable mechanism proposed for forming titanium diboride according to a "vapour - melt - crystal" pattern was examined, covering condensation of titanium vapour in the form of aerosol, boriding of nanoscale melt droplets by boron hydrides and crystallization of titanium - boron melt. The comprehensive physical - chemical certification of titanium diboride was carried out, including the study of its crystal structure, phase and chemical composition, dispersion, morphology and particle oxidation. Technological application prospects for use of titanium diboride nanoscale powder as constituent element in the wettable coating for carbon cathodes having excellent physical and mechanical performance and protective properties.

  6. Facile synthesis of silicon carbide-titanium dioxide semiconducting nanocomposite using pulsed laser ablation technique and its performance in photovoltaic dye sensitized solar cell and photocatalytic water purification

    NASA Astrophysics Data System (ADS)

    Gondal, M. A.; Ilyas, A. M.; Baig, Umair

    2016-08-01

    Separation of photo-generated charge carriers (electron and holes) is a major approach to improve the photovoltaic and photocatalytic performance of metal oxide semiconductors. For harsh environment like high temperature applications, ceramic like silicon carbide is very prominent. In this work, 10%, 20% and 40% by weight of pre-oxidized silicon carbide was coupled with titanium dioxide (TiO2) to form nanocomposite semiconductor via elegant pulsed laser ablation in liquid technique using second harmonic 532 nm wavelength of neodymium-doped yttrium aluminium garnet (Nd-YAG) laser. In addition, the effect of silicon carbide concentration on the performance of silicon carbide-titanium dioxide nanocomposite as photo-anode in dye sensitized solar cell and as photocatalyst in photodegradation of methyl orange dye in water was also studied. The result obtained shows that photo-conversion efficiency of the dye sensitized solar cell was improved from 0.6% to 1.65% and the percentage of methyl orange dye removed was enhanced from 22% to 77% at 24 min under ultraviolet-visible solar spectrum in the nanocomposite with 10% weight of silicon carbide. This remarkable performance enhancement could be due to the improvement in electron transfer phenomenon by the presence of silicon carbide on titanium dioxide.

  7. Nanorough titanium surfaces reduce adhesion of Escherichia coli and Staphylococcus aureus via nano adhesion points.

    PubMed

    Lüdecke, Claudia; Roth, Martin; Yu, Wenqi; Horn, Uwe; Bossert, Jörg; Jandt, Klaus D

    2016-09-01

    Microbial adhesion to natural and synthetic materials surfaces is a key issue e.g. in food industry, sewage treatment and most importantly in the biomedical field. The current development and progress in nanoscale structuring of materials surfaces to control microbial adhesion requires an advanced understanding of the microbe-material-interaction. This study aimed to investigate the nanostructure of the microbe-material-interface and link it to microbial adhesion kinetics as function of titanium surface nanoroughness to gain new insight into controlling microbial adhesion via materials' surface nanoroughness. Adhesion of Escherichia coli and Staphylococcus aureus was statistically significantly reduced (p≤0.05) by 55.6 % and 40.5 %, respectively, on physical vapor deposited titanium thin films with a nanoroughness of 6nm and the lowest surface peak density compared to 2nm with the highest surface peak density. Cross-sectioning of the microbial cells with a focused ion beam (FIB) and SEM imaging provided for the first time direct insight into the titanium-microbe-interface. High resolution SEM micrographs gave evidence that the surface peaks are the loci of initial contact between the microbial cells and the material's surface. In a qualitative model we propose that the initial microbial adhesion on nanorough surfaces is controlled by the titanium surface peak density via nano adhesion points. This new understanding will help towards the design of materials surfaces for controlling microbial adhesion.

  8. Defective titanium dioxide single crystals exposed by high-energy {001} facets for efficient oxygen reduction

    NASA Astrophysics Data System (ADS)

    Pei, Dan-Ni; Gong, Li; Zhang, Ai-Yong; Zhang, Xing; Chen, Jie-Jie; Mu, Yang; Yu, Han-Qing

    2015-10-01

    The cathodic material plays an essential role in oxygen reduction reaction for energy conversion and storage systems. Titanium dioxide, as a semiconductor material, is usually not recognized as an efficient oxygen reduction electrocatalyst owning to its low conductivity and poor reactivity. Here we demonstrate that nano-structured titanium dioxide, self-doped by oxygen vacancies and selectively exposed with the high-energy {001} facets, exhibits a surprisingly competitive oxygen reduction activity, excellent durability and superior tolerance to methanol. Combining the electrochemical tests with density-functional calculations, we elucidate the defect-centred oxygen reduction reaction mechanism for the superiority of the reductive {001}-TiO2-x nanocrystals. Our findings may provide an opportunity to develop a simple, efficient, cost-effective and promising catalyst for oxygen reduction reaction in energy conversion and storage technologies.

  9. Defective titanium dioxide single crystals exposed by high-energy {001} facets for efficient oxygen reduction

    PubMed Central

    Pei, Dan-Ni; Gong, Li; Zhang, Ai-Yong; Zhang, Xing; Chen, Jie-Jie; Mu, Yang; Yu, Han-Qing

    2015-01-01

    The cathodic material plays an essential role in oxygen reduction reaction for energy conversion and storage systems. Titanium dioxide, as a semiconductor material, is usually not recognized as an efficient oxygen reduction electrocatalyst owning to its low conductivity and poor reactivity. Here we demonstrate that nano-structured titanium dioxide, self-doped by oxygen vacancies and selectively exposed with the high-energy {001} facets, exhibits a surprisingly competitive oxygen reduction activity, excellent durability and superior tolerance to methanol. Combining the electrochemical tests with density-functional calculations, we elucidate the defect-centred oxygen reduction reaction mechanism for the superiority of the reductive {001}-TiO2−x nanocrystals. Our findings may provide an opportunity to develop a simple, efficient, cost-effective and promising catalyst for oxygen reduction reaction in energy conversion and storage technologies. PMID:26493365

  10. Lactobacillusassisted synthesis of titanium nanoparticles

    PubMed Central

    2007-01-01

    An eco-friendlylactobacillussp. (microbe) assisted synthesis of titanium nanoparticles is reported. The synthesis is performed at room temperature. X-ray and transmission electron microscopy analyses are performed to ascertain the formation of Ti nanoparticles. Individual nanoparticles as well as a number of aggregates almost spherical in shape having a size of 40–60 nm are found.

  11. PLUTONIUM-URANIUM-TITANIUM ALLOYS

    DOEpatents

    Coffinberry, A.S.

    1959-07-28

    A plutonium-uranium alloy suitable for use as the fuel element in a fast breeder reactor is described. The alloy contains from 15 to 60 at.% titanium with the remainder uranium and plutonium in a specific ratio, thereby limiting the undesirable zeta phase and rendering the alloy relatively resistant to corrosion and giving it the essential characteristic of good mechanical workability.

  12. Synthesis of new antibacterial composite coating for titanium based on highly ordered nanoporous silica and silver nanoparticles.

    PubMed

    Massa, Miguel A; Covarrubias, Cristian; Bittner, Mauricio; Fuentevilla, Ignacio Andrés; Capetillo, Pavel; Von Marttens, Alfredo; Carvajal, Juan Carlos

    2014-12-01

    Infection is the most common factor that leads to dental titanium implant failure. Antibacterial implant surfaces based on nano-scale modifications of the titanium appear as an attractive strategy for control of peri-implantitis. In the present work, the preparation and antibacterial properties of a novel composite coating for titanium based on nanoporous silica and silver nanoparticles are presented. Starch-capped silver nanoparticles (AgNPs) were synthesized and then incorporated into sol-gel based solution system. The AgNP-doped nanoporous silica coatings were prepared on titanium surface using a combined sol-gel and evaporation-induced self-assembly (EISA) method. The coating nanostructure was characterized by XRD, SEM-EDX, and HR-TEM. Antibacterial activity was evaluated against Aggregatibacter actinomycetemcomitans, a representative pathogen of dental peri-implantitis. Colony-forming units (CFUs) were counted within the biofilm and at the planktonic state. Biofilm development was quantified using crystal violet staining and viability of adherent bacteria was confirmed with the Live/Dead fluorescence assay. Silica-based composite coating containing AgNPs (AgNP/NSC) was prepared on titanium surface by direct incorporation of AgNP suspension into the sol-gel system. The self-assembly technique enabled the spontaneous formation of a highly ordered nanoporosity in the coating structure, which is a desired property for osseointegration aspects of titanium implant surface. AgNP/NSC coating produces a strong antibacterial effect on titanium surface by not only killing the adherent bacteria but also reducing the extent of biofilm formation. Biofilm survival is reduced by more than 70% on the AgNP/NSC-modified titanium surface, compared to the control. This antibacterial effect was verified for up to 7 days of incubation. The long-term antibacterial activity exhibited by the nanostructured AgNP/NSC-titanium surface against A. actinomycetemcomitans suggests that this

  13. Construction of microenvironment onto titanium substrates to regulate the osteoblastic differentiation of bone marrow stromal cells in vitro and osteogenesis in vivo.

    PubMed

    Lai, Min; Cai, Kaiyong; Hu, Yan; Zhang, Yuan; Li, Liqi; Luo, Zhong; Hou, Yanhua; Li, Jinghua; Ding, Xingwei; Chen, Xiuyong

    2013-03-01

    To mimic the extracellular matrix of natural bone, apatite/gelatin composite was deposited onto nanostructured titanium substrates via a coprecipitation method, which was pretreated by potassium hydroxide and heat treatment to generate an anticorrosive nanostructured layer. The successful formation of the apatite/gelatin nanocomposite onto titanium surfaces was revealed by Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, atomic force microscopy (AFM), and thin film X-ray diffraction (TF-XRD) measurements, respectively. The immunofluorescence staining of vinculin revealed that the apatite/gelatin nanocomposite deposited titanium substrate was favorable for cell adhesion. More importantly, bone marrow stromal cells cultured onto the apatite/gelatin nanocomposite deposited titanium substrates displayed significantly higher (p < 0.05 or p < 0.01) proliferation and differentiation levels of alkaline phosphatase, mRNA expressions of osteocalcin (OC), osteopontin (OPN), and collagen type I (Col I), and OC content after culture for 7, 14, and 21 days, respectively, which was also revealed by the immunofluorescence analysis of OC and OPN expression. The deposition of apatite/gelatin nanocomposite improved bone density (p < 0.05) and bone-implant contact rate (p < 0.05), which was reflected by microcomputed tomography analysis and histological evaluation in vivo using a rabbit model. This work provides an approach to fabricate high-performance titanium-based implants with enhanced bone osseointegration.

  14. Nanostructures for peroxidases

    PubMed Central

    Carmona-Ribeiro, Ana M.; Prieto, Tatiana; Nantes, Iseli L.

    2015-01-01

    Peroxidases are enzymes catalyzing redox reactions that cleave peroxides. Their active redox centers have heme, cysteine thiols, selenium, manganese, and other chemical moieties. Peroxidases and their mimetic systems have several technological and biomedical applications such as environment protection, energy production, bioremediation, sensors and immunoassays design, and drug delivery devices. The combination of peroxidases or systems with peroxidase-like activity with nanostructures such as nanoparticles, nanotubes, thin films, liposomes, micelles, nanoflowers, nanorods and others is often an efficient strategy to improve catalytic activity, targeting, and reusability. PMID:26389124

  15. Nanostructured Multilayer Composite Coatings on Ceramic Cutting Tools for Finishing Treatment of High-Hardness Quenched Steels

    NASA Astrophysics Data System (ADS)

    Vereshchaka, A. A.; Batako, A. D.; Sotova, E. S.; Vereshchaka, A. S.

    2016-01-01

    The functional role of nanostructured multilayer composite coatings (NMCC) deposited on the operating surfaces of replaceable faceted cutting inserts (CI) from cutting ceramics based on aluminum oxides with additives of titanium carbides is studied. It is shown that the developed NMCC not only raise substantially the endurance of the ceramic tools under high-speed dry treatment of quenched steels but also improve the quality and accuracy of processing of the parts and the ecological parameters of the cutting process.

  16. Visible absorption spectra of the 4f electron transitions of neodymium, praseodymium, holmium and erbium complexes with fleroxacin and their analytical application.

    PubMed

    Wang, Naixing; Jiang, Wei; Xu, Xiuqin; Si, Zhikun; Bai, Haitao; Tian, Cong

    2002-05-01

    The absorption spectra of the 4f electron transitions of neodymium, praseodymium, holmium and erbium complexes with fleroxacin in the presence of cetylpyridinium chloride were studied by normal and derivative spectrophotometry. Their molar absorptivity at the maximum absorption bands are about 5.3 (at 571 nm) times greater for neodymium, 2.8 (at 483 nm) times greater for praseodymium, 12.6 (at 448.5 nm) times greater for holmium and 9.7 (at 519 nm) times greater for erbium than those in the absence of complexing agents. The second-derivative spectrum is used both to eliminate the interference from other rare earths and to improve the sensitivity. Beer's law is obeyed from 3.0 - 70 microg ml(-1) for neodymium and holmium, from 6.0 - 70 microg ml(-1) for erbium, and from 12.0 - 70 microg ml(-1) for praseodymium. The relative standard deviations are 1.9% and 1.5% for 7.5 microg ml(-1) of neodymium and holmium, and 2.1% and 1.6% for 15.0 microg ml(-1) of praseodymium and erbium, respectively. Their detection limits (signal-to-noise ratio = 2) are 3.2 microg ml(-1), 1.3 microg ml(-1), (1.1) microg ml(-1) and 2.5 microg ml(-1) for praseodymium, neodymium, holmium and erbium, respectively. A new system for the simultaneous determinations of the praseodymium, neodymium, holmium and erbium in rare earth mixtures with good accuracy and selectivity is proposed.

  17. Scientific basis for creation of construction materials based on titanium and alumina minerals

    NASA Astrophysics Data System (ADS)

    Kotova, O.; Shmakova, A.; Ponaryadov, A.

    2017-02-01

    Currently there is a need in affordable and accessible materials with specific physical and chemical properties. Al- and Ti-minerals are excellent test objects for correlation between structure and physical properties of mineral. For example, corundum and ilmenite are related to the same structural type (rhombohedral lattice R3) and possess various physical properties. With the help of modern equipment we studied titanium- and aluminum-containing concentrates of natural raw and also products of various kinds of influences on them, which showed signs of nanostructuring. We observed methods of directional change of physical and chemical characteristics of Al- and Ti-minerals and creation of new commercial products.

  18. Tensile properties of titanium electrolytically charged with hydrogen

    NASA Technical Reports Server (NTRS)

    Smith, R. J.; Otterson, D. A.

    1971-01-01

    Yield strength, ultimate tensile strength, and elongation were studied for annealed titanium electrolytically charged with hydrogen. The hydrogen was present as a surface hydride layer. These tensile properties were generally lower for uncharged titanium than for titanium with a continuous surface hydride; they were greater for uncharged titanium than for titanium with an assumed discontinuous surface hydride. We suggest that the interface between titanium and titanium hydride is weak. And the hydride does not necessarily impair strength and ductility of annealed titanium. The possibility that oxygen and/or nitrogen can embrittle titanium hydride is discussed.

  19. Past Hydrological Variability in the Congo Basin inferred from Neodymium Isotopes

    NASA Astrophysics Data System (ADS)

    Bayon, G.

    2015-12-01

    Major events of vegetation changes and soil erosion occurred in Central Africa during the last few millennia, at a time when the first farmers settled in the rainforest. The palaeoclimatic context in which these environmental changes took place still remains poorly constrained. Improving our knowledge on the drivers of past hydrological variability in Central Africa is important to further evaluate the relative role of climate versus humans in shaping late Holocene African landscapes. In this study, we have used neodymium (Nd) isotopes in a marine sediment core to reconstruct the composition of the sediment load exported from the Congo Basin during the Holocene. Core KZR23 was recovered at 2200 m water depth from within the Congo submarine canyon and is characterized by high sedimentation rates (about 2m/kyr), thereby allowing reconstruction of past river sediment discharge at an unprecedented high temporal resolution. A suite of river particulate samples collected from the main tributaries within the Congo watershed was analyzed in order to tag each major sub-basin with the characteristic geochemical and Nd isotopic signatures of its source region. In parallel, an annual series of suspended particles sampled on a monthly basis at the Congo River ORE-HYBAM station (Brazzaville) was also analyzed to characterize the seasonality of sediment provenance in relation with present hydrological cycle. Using Nd isotopes as tracers for sediment provenance together and other proxy data for past erosion, vegetation and rainfall patterns (i.e. bulk sediment radiocarbon data, pollens, biomarkers, compound-specific isotope analyses), we will provide a more comprehensive picture of past hydrological variability in the Congo Basin for the Holocene period.

  20. A spectrophotometric study of neodymium(III) complexation in chloride solutions

    NASA Astrophysics Data System (ADS)

    Migdisov, Art A.; Williams-Jones, A. E.

    2002-12-01

    The formation constants of neodymium complexes in chloride solutions have been determined spectrophotometrically at temperatures of 25 to 250°C and a pressure of 50 bars. The simple ion, Nd 3+, is dominant at 25°C, whereas NdCl 2+ and NdCl 2+ are the dominant species at elevated temperatures. Equilibrium constants were calculated for the following reactions: Nd 3+ + Cl - = NdCl 2+ β 1, Nd 3+ + 2 · Cl - = NdCl +2 β 2. The values of β 1 were found to be identical within experimental error to the values reported by Gammons et al. (1996) but substantially different from those proposed by Stepanchikova and Kolonin (1999). The values of β 2 obtained in this study agree relatively well with those of Gammons et al. (1996); differences are greatest at intermediate temperature and reach a maximum of one half an order of magnitude at 200°C. Theoretical estimates of β 1 and β 2 by Haas et al. (1995) using the revised Helgeson-Kirkham-Flowers (HKF) equation of state predict lower stability of NdCl 2+ and NdCl 2+ at temperatures above 150°C than determined in this study. A new fit to the HKF equation of state is therefore proposed, which yields values for β 1 and β 2 similar to those obtained experimentally. Using the formation constants reported in this study, we predict that typical seafloor hydrothermal vent fluids will contain a maximum concentration of Nd of ˜2 ppb. This value is several orders of magnitude lower than would be required to explain the levels of Nd mobility commonly reported for seafloor hydrothermal systems and suggests that other ligands may be more important than Cl in transporting rare earth elements in the Earth's crust.

  1. A spectrophotometric study of neodymium(III) complexation in sulfate solutions at elevated temperatures

    NASA Astrophysics Data System (ADS)

    Migdisov, Art. A.; Reukov, V. V.; Williams-Jones, A. E.

    2006-02-01

    The formation constants of neodymium complexes in sulfate solutions have been determined spectrophotometrically at temperatures of 30-250 °C and a pressure of 100 bars. The dominant species in the solution are NdSO 4+ and Nd(SO 4) 2-, with the latter complex being more important at higher temperature. Equilibrium constants were calculated for the following reactions: Nd+SO4=NdSO4,β1; Nd+2·SO4=Nd(SO4)2,β2; NdSO4+SO4=Nd(SO4)2,Ks. The values of β1 and β2, were determined for 30 and 100 °C, whereas for higher temperatures it was only possible to determine the stepwise formation constant Ks. The values of the formation constants obtained in this study for 30 and 100 °C are in excellent agreement with those predicted theoretically by Wood [Wood, S.A., 1990b. The aqueous geochemistry of the rare-earth elements and yttrium. 2. Theoretical predictions of speciation in hydrothermal solutions to 350 °C at saturation water vapor pressure. Chem. Geol.88 (1-2), 99-125] and Haas et al. [Haas, J.R., Shock, E.L., Sassani, D.C., 1995. Rare earth elements in hydrothermal sysytems: estimates of standard partial molal thermodynamic properties of aqueous complexes of the rare earth elements at high pressures and temperatures. Geochim. Cosmochim. Acta59 (21), 4329-4350], and those for the stepwise formation constant ( Ks) agree reasonably well with the predictions of Wood (1990b).

  2. Neodymium isotopic composition of intermediate and deep waters in the glacial southwest Pacific

    NASA Astrophysics Data System (ADS)

    Noble, Taryn L.; Piotrowski, Alexander M.; McCave, I. Nick

    2013-12-01

    Neodymium (Nd) isotopes, tracers of deep water mass source and mixing, were measured on sedimentary planktic foraminifera with authigenic coatings from a depth-transect of cores (1400-4800 m) from Chatham Rise in the southwest Pacific, over the past 30 ka. We observe deglacial variations in the Nd isotopic composition, which showed an average glacial composition of ɛNd=-5.0 (1σ; ±0.3n=4) for cores sites below 3200 mbsl. No significant deglacial variation was observed in the Nd isotopic composition of intermediate depth waters (1400 mbsl), in contrast with benthic foraminifera δC13 data. The deglacial ɛNd shift of CDW in the southwest Pacific is consistent with changes observed in the deep South Atlantic and Equatorial Indian Ocean, but ɛNd values are offset by ˜1ɛNd-unit to more radiogenic values throughout the deglacial records, likely due to admixture of a Nd isotope signal which was modified in the Southern Ocean or Pacific, perhaps by boundary exchange. However, this modification did not overprint the deglacial Nd isotope change. The consistent deglacial evolution of ɛNd in the South Atlantic, Equatorial Indian and southwest Pacific CDW, is evidence for the connection of CDW during the glacial, and propagation of diminished North Atlantic Deep Water export to the glacial Southern Ocean. In contrast, spatial heterogeneities in the benthic foraminifera δC13 of CDW have been observed in the Atlantic, Indian and Pacific basins of the deep glacial Southern Ocean. The Nd isotope data implies a well-connected deep Southern Ocean, which transported waters from the Atlantic to the Indian and Pacific oceans, during the glacial. This suggests that basin-scale variability in the glacial δC13 composition of CDW was unrelated to circulation changes.

  3. Neodymium associated with foraminiferal carbonate as a recorder of seawater isotopic signatures

    NASA Astrophysics Data System (ADS)

    Tachikawa, Kazuyo; Piotrowski, Alexander M.; Bayon, Germain

    2014-03-01

    Neodymium isotopic ratios in marine environments have been used as a tracer of water masses and exchange processes between dissolved and particulate phases. The interest in this tracer has been growing with improvement of our knowledge on its chemical behaviour in the modern ocean and the identification of sedimentary phases that preserve past seawater ɛNd values. In the last few decades the Nd isotopic composition measured on Fe-Mn crusts, sediment leachates, bulk carbonate fraction, corals and fish teeth have been increasingly interpreted in the context of understanding the role of the ocean in paleoclimate changes. In particular, calcareous foraminiferal tests (shells) have acquired increasing attention as an archive of seawater Nd isotopic signatures, because it allows continuous high-resolution records to be measured and directly compared to other proxies including stable isotopes and trace metals. The main challenge of interpreting the Nd isotopic composition of foraminifera is determining the origin of the Nd preserved within them. In this review, we present an overview of methodological progress including that of bulk foraminifera and microanalyses within foraminiferal tests, as well as geochemical meaning of extracted Nd concentrations and isotopic compositions. The growing body of evidence suggests that Nd isotopic signatures of sedimentary planktonic foraminifera correspond to bottom water values rather than surface water ones. The Nd-rich phases associated with sedimentary foraminifera are adhesive nano-scale particles of Mn and Fe oxides and hydroxides, and Mn-rich carbonates formed within layers of foraminiferal calcite. Mechanical cleaning to remove clay minerals is likely to be sufficient in most cases to reconstruct past bottom water circulations. Unresolved issues include the potential influence of pore water Nd on ɛNd values extracted from sedimentary foraminiferal tests under different sedimentalogical and oceanographic conditions.

  4. Development of an empirical kinetic model for sonocatalytic process using neodymium doped zinc oxide nanoparticles.

    PubMed

    Khataee, Alireza; Vahid, Behrouz; Saadi, Shabnam; Joo, Sang Woo

    2016-03-01

    The degradation of Acid Blue 92 (AB92) solution was investigated using a sonocatalytic process with pure and neodymium (Nd)-doped ZnO nanoparticles. The nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The 1% Nd-doped ZnO nanoparticles demonstrated the highest sonocatalytic activity for the treatment of AB92 (10 mg/L) with a degradation efficiency (DE%) of 86.20% compared to pure ZnO (62.92%) and sonication (45.73%) after 150 min. The results reveal that the sonocatalytic degradation followed pseudo-first order kinetics. An empirical kinetic model was developed using nonlinear regression analysis to estimate the pseudo-first-order rate constant (kapp) as a function of the operational parameters, including the initial dye concentration (5-25 mg/L), doped-catalyst dosage (0.25-1 g/L), ultrasonic power (150-400 W), and dopant content (1-6% mol). The results from the kinetic model were consistent with the experimental results (R(2)=0.990). Moreover, DE% increases with addition of potassium periodate, peroxydisulfate, and hydrogen peroxide as radical enhancers by generating more free radicals. However, the addition of chloride, carbonate, sulfate, and t-butanol as radical scavengers declines DE%. Suitable reusability of the doped sonocatalyst was proven for several consecutive runs. Some of the produced intermediates were also detected by GC-MS analysis. The phytotoxicity test using Lemna minor (L. minor) plant confirmed the considerable toxicity removal of the AB92 solution after treatment process.

  5. Effect of neodymium substitution on structural and ferroelectric properties of BNT ceramics

    SciTech Connect

    Pal, Vijayeta; Dwivedi, R.K.; Thakur, O.P.

    2014-03-01

    Graphical abstract: - Highlights: • First time, we synthesized (Bi{sub 1−x}Nd{sub x}){sub 0.5}Na{sub 0.5}TiO{sub 3} system by semi wet technique. • Grain size reduced with doping and Nd acts as an inhibitor in the grain growth. • Specimen with x = 0.02 exhibits excellent ferroelectric properties at RT. • P–E loops show the co-existence of polar and non polar regions around ‘T{sub d}’. - Abstract: Polycrystalline specimens of (Bi{sub 1−x}Nd{sub x}){sub 0.5}Na{sub 0.5}TiO{sub 3} (BNNT) ceramic system with compositions x ≤ 0.04 were synthesized by semi-wet technique using ethylene glycol precursor. Structural and electrical properties were investigated in detail to observe the effect of neodymium (Nd) substitution in BNT system. XRD patterns for all the specimens showed single phase formation with rhombohedral structure. Field emission scanning electron micrographs (FE-SEM) revealed that the grain growth was inhibited significantly with Nd content. The temperature dependence behaviour of dielectric constant revealed that the depolarisation temperature ‘T{sub d}’ decreases whereas temperature of maximum dielectric constant ‘T{sub m}’ increases with Nd concentration. The piezoelectric charge coefficient (d{sub 33}) showed maxima at x = 0.02 and well defined ferroelectric behaviour was observed for all the samples.

  6. Electrochemical properties of dual phase neodymium-doped ceria alkali carbonate composite electrolytes in intermediate temperature

    NASA Astrophysics Data System (ADS)

    Kim, Ji-Tae; Lee, Tae-Hee; Park, Ka-Young; Seo, Yongho; Kim, Ki Buem; Song, Sun-Ju; Park, Byoungnam; Park, Jun-Young

    2015-02-01

    Composite electrolyte materials composed of neodymium-doped ceria (Nd0.2Ce0.8O1.9; NDC) and (Li-0.5Na)2CO3 are investigated to understand the unique behaviors of their multi-ionic conduction. In the intermediate temperature, the NDC-based carbonate composite electrolytes exhibit a much higher conductivity compared to pure NDC. It has been claimed that the oxide ions are transported in the doped-ceria phase via oxygen vacancies and the protons are conducted through the second carbonate phase, thereby resulting in an enhanced ionic conductivity. However, it has not been experimentally demonstrated if the proton conduction within the carbonate phase aided in improving the conductivity of oxygen ions in the composite system. Hence, the primary objective of this work is to cultivate a deeper insight into the conduction property of these composites as an attempt to clarify the ionic transport phenomenon responsible for enhanced conductivity. Electrical conductivities of NDC and NDC/carbonate materials are investigated as a function of oxygen partial pressure and vapor pressure of water to understand transport properties of composite electrolytes. The ionic and electronic transference numbers of composite electrolytes are measured by the oxygen- and hydrogen-concentration cells containing water. The dominant charge carriers are identified quantitatively through the analysis of the partial conductivity of proton, oxygen ions, and electrons (holes). Understanding the transport properties and transference numbers of composite electrolytes can contribute to the development of commercial solid oxide fuel cells, which can be done by reducing the operating temperature using a highly ionic conductive NDC/carbonate composite electrolyte at the intermediate temperature.

  7. High resolution neodymium characterization along the Mediterranean Sea margins: implications for ɛNd modeling.

    NASA Astrophysics Data System (ADS)

    Ayache, Mohamed; Dutay, Jean-claude; Arsouze, Thomas; Jeandel, Catherine; Revillon, Sidonie

    2016-04-01

    An extensive compilation of published neodymium (Nd) concentrations and isotopic compositions (ɛNd) was realized in order to establish a new database and a map (using a high resolution geological map of the area) of the distribution of these parameters for all the Mediterranean margins. Data were extracted from different kinds of samples: river solid discharge deposited on the shelf, sedimentary material collected on the margin or geological material outcropping above or close to a margin. Additional analyses of surface sediments were done, in order to improve this dataset in key areas (e.g Sicilian strait). The Mediterranean margin Nd isotopic signatures vary from non-radiogenic values around the Gulf of Lions, (ɛNd values -11) to radiogenic values around the Aegean and the Levantine sub-basins up to +6. Using a high resolution regional oceanic model (1/12° of horizontal resolution), ɛNd distribution was simulated for the first time in the Mediterranean Sea. The high resolution of the model provides the opportunity to study in more details the processes governing the Nd isotope distribution in the marine environment. This work highlights that a significant interannual variability of ɛNd distribution in seawater could occur. In particular, important hydrological events such as the Eastern Mediterranean Transient (EMT), associated with deep water formed in the Aegean sub-basin, could induce a shift in Nd IC at intermediate depths that could be noticeable in the Western part of the basin. This highlights that the temporal and geographical variations of ɛNd could represent an interesting insight of Nd as a quasi-conservative tracer of water masses in the Mediterranean Sea, in particular in the context of paleo-oceanographic applications, i.e. to explore if EMT-type signatures occurred in the past (Roether et al., 2014, Gacic et al., 2011).

  8. Clinical efficacy of the dual-pulsed Q-switched neodymium:yttrium-aluminum-garnet laser: Comparison with conservative mode.

    PubMed

    Kim, Byung Wook; Lee, Mi Hye; Chang, Sung Eun; Yun, Woo Jin; Won, Chong Hyun; Lee, Mi Woo; Choi, Jee Ho; Moon, Kee Chan

    2013-12-01

    The quality (Q)-switched neodymium:yttrium-aluminum-garnet (Nd:YAG) laser is one of the first non-ablative lasers to be used for facial resurfacing and photorejuvenation. Recently, the method of low-fluence Q-switched Nd:YAG lasers known as 'laser toning' has been used for non-ablative skin rejuvenation and for the treatment of melasma in Asian countries. We report our experience of using a novel Q-switched Nd:YAG laser that was operated as a dual pulse at half fluence and 140-μs intervals compared with conservative mode laser.

  9. Cerium(III) and neodymium(III) complexes as scavengers of X/XO-derived superoxide radical.

    PubMed

    Kostova, Irena; Traykova, Maria

    2006-09-01

    The cerium (III) and neodymium (III) complexes with 3,3'-benzylidenebis[4-hydroxycoumarin] were synthesized and characterized by different analytical and spectral methods. The synthesis of these complexes is taken into consideration with cytotoxic screening and study of their antioxidant effect. Their cytotoxicity toward cancerous cell cultures correlated with the weakness of the coordinative bond between the cation and organic ligand and with the capability to scavenge superoxide radicals as well. On the basis of the data reported by us earlier and our new results, it was proposed that cerium (III) complex with 3,3'-benzylidenebis[4-hydroxycoumarin] might induce intracellular acidification along with control over the extracellular oxidative stress.

  10. Acute effects of anti-inflammatory drugs on neodymium:yttrium aluminum garnet laser-induced uveitis in dogs.

    PubMed

    Millichamp, N J; Dziezyc, J; Rohde, B H; Chiou, G C; Smith, W B

    1991-08-01

    Dogs were treated with flunixin meglumine, a cyclooxygenase inhibitor; L-651,896, a 5-lipoxygenase inhibitor; and matrine, a herbal anti-inflammatory drug. Acute inflammation was induced in the eyes by disruption of the anterior lens capsule, using a neodymium:yttrium aluminum garnet laser. Intraocular pressure, pupil diameter, and eicosanoid production in the aqueous humor were measured. Statistically significant effects were seen in the eyes of flunixin meglumine-treated dogs where mydriasis was maintained and aqueous prostaglandin E2 concentration was reduced.

  11. Large-mode-area single-mode-output Neodymium-doped silicate glass all-solid photonic crystal fiber.

    PubMed

    Li, Wentao; Chen, Danping; Qinling, Zhou; Hu, Lili

    2015-07-24

    We have demonstrated a 45 μm core diameter Neodymium-doped all-solid silicate glass photonic crystal fiber laser with a single mode laser output. The structure parameters and modes information of the fiber are both demonstrated by theoretical calculations using Finite Difference Time Domain (FDTD) method and experimental measurements. Maximum 0.8 W output power limited by launched pump power has been generated in 1064 nm with laser beam quality factor M(2) 1.18.

  12. Large-mode-area single-mode-output Neodymium-doped silicate glass all-solid photonic crystal fiber

    PubMed Central

    Li, Wentao; Chen, Danping; Qinling, Zhou; Hu, Lili

    2015-01-01

    We have demonstrated a 45 μm core diameter Neodymium-doped all-solid silicate glass photonic crystal fiber laser with a single mode laser output. The structure parameters and modes information of the fiber are both demonstrated by theoretical calculations using Finite Difference Time Domain (FDTD) method and experimental measurements. Maximum 0.8 W output power limited by launched pump power has been generated in 1064 nm with laser beam quality factor M2 1.18. PMID:26205850

  13. EDITORIAL: Nanostructured solar cells Nanostructured solar cells

    NASA Astrophysics Data System (ADS)

    Greenham, Neil C.; Grätzel, Michael

    2008-10-01

    Conversion into electrical power of even a small fraction of the solar radiation incident on the Earth's surface has the potential to satisfy the world's energy demands without generating CO2 emissions. Current photovoltaic technology is not yet fulfilling this promise, largely due to the high cost of the electricity produced. Although the challenges of storage and distribution should not be underestimated, a major bottleneck lies in the photovoltaic devices themselves. Improving efficiency is part of the solution, but diminishing returns in that area mean that reducing the manufacturing cost is absolutely vital, whilst still retaining good efficiencies and device lifetimes. Solution-processible materials, e.g. organic molecules, conjugated polymers and semiconductor nanoparticles, offer new routes to the low-cost production of solar cells. The challenge here is that absorbing light in an organic material produces a coulombically bound exciton that requires dissociation at a donor-acceptor heterojunction. A thickness of at least 100 nm is required to absorb the incident light, but excitons only diffuse a few nanometres before decaying. The problem is therefore intrinsically at the nano-scale: we need composite devices with a large area of internal donor-acceptor interface, but where each carrier has a pathway to the respective electrode. Dye-sensitized and bulk heterojunction cells have nanostructures which approach this challenge in different ways, and leading research in this area is described in many of the articles in this special issue. This issue is not restricted to organic or dye-sensitized photovoltaics, since nanotechnology can also play an important role in devices based on more conventional inorganic materials. In these materials, the electronic properties can be controlled, tuned and in some cases completely changed by nanoscale confinement. Also, the techniques of nanoscience are the natural ones for investigating the localized states, particularly at

  14. Titanium-Oxygen Reactivity Study

    NASA Technical Reports Server (NTRS)

    Chafey, J. E.; Scheck, W. G.; Witzell, W. E.

    1962-01-01

    A program has been conducted at Astronautics to investigate the likelihood of occurrence of the catastrophic oxidation of titanium alloy sheet under conditions which simulate certain cases of accidental failure of the metal while it is in contact with liquid or gaseous oxygen. Three methods of fracturing the metal were used; they consisted of mechanical puncture, tensile fracture of welded joints, and perforation by very high velocity particles. The results of the tests which have been conducted provide further evidence of the reactivity of titanium with liquid and gaseous oxygen. The evidence indicates that the rapid fracturing of titanium sheet while it is in contact with oxygen initiates the catastrophic oxidation reaction. Initiation occurred when the speed of the fracture was some few feet per second, as in both the drop-weight puncture tests and the static tensile fracture tests of welded joints, as well as when the speed was several thousand feet per second, as in the simulated micrometeoroid penetration tests. The slow propagation of a crack, however, did not initiate the reaction. It may logically be concluded that the localized frictional heat of rapid fracture and/or spontaneous oxidation (exothermic) of minute particles emanating from the fracture cause initiation of the reaction. Under conditions of slow fracture, however, the small heat generated may be adequately dissipated and the reaction is not initiated. A portion of the study conducted consisted of investigating various means by which the reaction might be retarded or prevented. Providing a "barrier" at the titanium-oxygen interface consisting of either aluminum metal or a coating of a petroleum base corrosion inhibitor appeared to be only partially effective in retarding the reaction. The accidental puncturing or similar rupturing of thin-walled pressurized oxygen tanks on missiles and space vehicle will usually constitute loss of function, and may sometimes cause their catastrophic destruction

  15. Antimicrobial titanium/silver PVD coatings on titanium

    PubMed Central

    Ewald, Andrea; Glückermann, Susanne K; Thull, Roger; Gbureck, Uwe

    2006-01-01

    Background Biofilm formation and deep infection of endoprostheses is a recurrent complication in implant surgery. Post-operative infections may be overcome by adjusting antimicrobial properties of the implant surface prior to implantation. In this work we described the development of an antimicrobial titanium/silver hard coating via the physical vapor deposition (PVD) process. Methods Coatings with a thickness of approximately 2 μm were deposited on titanium surfaces by simultaneous vaporisation of both metals in an inert argon atmosphere with a silver content of approximately 0.7 – 9% as indicated by energy dispersive X-ray analysis. On these surfaces microorganisms and eukaryotic culture cells were grown. Results The coatings released sufficient silver ions (0.5–2.3 ppb) when immersed in PBS and showed significant antimicrobial potency against Staphylococcus epidermis and Klebsiella pneumoniae strains. At the same time, no cytotoxic effects of the coatings on osteoblast and epithelial cells were found. Conclusion Due to similar mechanical performance when compared to pure titanium, the TiAg coatings should be suitable to provide antimicrobial activity on load-bearing implant surfaces. PMID:16556327

  16. Efficient and Robust Thermoelectric Power Generation Device Using Hot-Pressed Metal Contacts on Nanostructured Half-Heusler Alloys

    NASA Astrophysics Data System (ADS)

    Joshi, Giri; Poudel, Bed

    2016-12-01

    We report an efficient thermoelectric device with power density of 8.9 W/cm2 and efficiency of 8.9% at 678°C temperature difference using hot-pressed titanium metal contact layers on nanostructured half-Heusler materials. The high power density and efficiency are due to the efficient nanostructured materials and very low contact resistance of 1 μΩ cm2 between the titanium layer and half-Heusler material. Moreover, the bonding strength between the titanium and half-Heusler is more than 50 MPa, significantly higher compared with conventional contact metallization methods. The low contact resistance and high bonding strength are due to thin-layer diffusion of titanium (<100 μm) into the half-Heusler at high temperature (>600°C). The low contact resistance and high bonding strength result in a stable and efficient power generation device with great potential for use in recovery of waste heat, e.g., in automotive and industrial applications.

  17. Formation of crystalline titanium(IV) phosphates from titanium(III) solutions

    SciTech Connect

    Bortun, A.; Jaimez, E.; Llavona, R.; Garcia, J.R.; Rodriguez, J.

    1995-04-01

    Crystalline phases of titanium (IV) phosphate have been obtained from titanium(III) chloride in phosphoric acid solutions. The {alpha}-titanium phosphate synthesis is possible at low temperature (60--80 C). {gamma}-Titanium phosphate is obtained by reflux with very concentrated phosphoric acid in 3--5 hours by oxidation with O{sub 2}. The influence in these reactions of several factors (concentration of reagents, molar ratio P:Ti in the reaction mixture, temperature and reaction) was studied. The {alpha}-titanium phosphate formation takes place in several steps through the sequential formation of amorphous titanium(IV) phosphate, {gamma}-titanium phosphate and/or a semicrystalline titanium(IV) hydroxophosphate, Ti(OH){sub 2}(HPO{sub 4}){center_dot}H{sub 2}O.

  18. Photocatalytic properties of nanostructured TiO2 surfaces

    NASA Astrophysics Data System (ADS)

    Moore, Lauren; Luttrell, Timothy; Batzill, Matthias

    2012-02-01

    Photocatalytic chemical reactions are actively explored for direct production of chemical fuels from sun light through electrolysis or for the clean-up of organic pollutants through photocatalysis. Titanium dioxide is a prototypical photocatalyst which has been studied extensively. However, there are still unanswered questions regarding the relationship between surface morphology and photocatalytic properties. In this study, we used ion beam assisted surface nanopatterning and UV-catalysis to investigate the dependence of photoreactivity on surface nanostructures. Energetic argon gas ions were used to induce self-formation of nanopatterns on TiO2 surfaces and the structure formation was characterized by atomic force microscopy. The influence of the surface structure on the photochemical properties was assessed through photocatalytic degradation of methyl orange in aqueous solution with a flat sample and a nanopatterned sample of TiO2, respectively. The resulting absorbance spectrums were then compared.

  19. Mechanical design of DNA nanostructures.

    PubMed

    Castro, Carlos E; Su, Hai-Jun; Marras, Alexander E; Zhou, Lifeng; Johnson, Joshua

    2015-04-14

    Structural DNA nanotechnology is a rapidly emerging field that has demonstrated great potential for applications such as single molecule sensing, drug delivery, and templating molecular components. As the applications of DNA nanotechnology expand, a consideration of their mechanical behavior is becoming essential to understand how these structures will respond to physical interactions. This review considers three major avenues of recent progress in this area: (1) measuring and designing mechanical properties of DNA nanostructures, (2) designing complex nanostructures based on imposed mechanical stresses, and (3) designing and controlling structurally dynamic nanostructures. This work has laid the foundation for mechanically active nanomachines that can generate, transmit, and respond to physical cues in molecular systems.

  20. 40 CFR 721.10602 - Lead niobium titanium zirconium oxide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... the following substances: Lead strontium titanium zirconium oxide (PMN P-11-270; CAS No. 61461-40-3... strontium titanium tungsten oxide (PMN P-11-272; CAS No. 1262279-30-0); Lanthanum lead titanium...

  1. 40 CFR 721.10602 - Lead niobium titanium zirconium oxide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... the following substances: Lead strontium titanium zirconium oxide (PMN P-11-270; CAS No. 61461-40-3... strontium titanium tungsten oxide (PMN P-11-272; CAS No. 1262279-30-0); Lanthanum lead titanium...

  2. Synthesis and thermal stability studies of a series of metastable Dion–Jacobson double-layered neodymium-niobate perovskites

    SciTech Connect

    Josepha, Elisha A.; Farooq, Sara; Mitchell, Cinnamon M.; Wiley, John B.

    2014-08-15

    The Dion–Jacobson double-layered perovskite, RbNdNb{sub 2}O{sub 7}, is used as a precursor to synthesize the series ANdNb{sub 2}O{sub 7} (A=H, Li, Na, K, NH{sub 4}, Ag), and (MCl)NdNb{sub 2}O{sub 7} (M=Mn, Fe, Cu) through ion-exchange reactions ≤400 °C. Thermal stability studies indicated that most of these compounds are metastable. A combination of X-ray powder diffraction and differential thermal analysis were used to determine various low temperature decomposition pathways; these pathways were very dependent on the interlayer species. Overall the ANdNb{sub 2}O{sub 7} series was found to be less stable than the corresponding lanthanides, ALaNb{sub 2}O{sub 7}. - Graphical abstract: A new series of topochemically-prepared metastable neodymium-containing layered perovskites are studied. - Highlights: • A series of new layered neodymium containing perovskites were synthesized by ion exchange. • Products were studied by variable temperature X-ray diffraction and thermal analysis. • Most of the series are metastable showing exothermic transitions on decomposition. • The Nd compounds are less stable due to the smaller size of the Nd relative to La.

  3. Assessment of optical path length in tissue using neodymium and water absorptions for application to near-infrared spectroscopy.

    PubMed

    Nighswander-Rempel, Stephen P; Kupriyanov, Valery V; Shaw, R Anthony

    2005-01-01

    Quantitative analysis of blood oxygen saturation using near-IR spectroscopy is made difficult by uncertainties in both the absolute value and the wavelength dependence of the optical path length. We introduce a novel means of assessing the wavelength dependence of path length, exploiting the relative intensities of several absorptions exhibited by an exogenous contrast agent (neodymium). Combined with a previously described method that exploits endogenous water absorptions, the described technique estimates the absolute path length at several wavelengths throughout the visible/near-IR range of interest. Isolated rat hearts (n = 11) are perfused separately with Krebs-Henseleit buffer (KHB) and a KHB solution to which neodymium had been added, and visible/near-IR spectra are acquired using an optical probe made up of emission and collection fibers in concentric rings of diameters 1 and 3 mm, respectively. Relative optical path lengths at 520, 580, 679, 740, 800, 870, and 975 nm are 0.41+/-0.13, 0.49+/-0.21, 0.90+/-0.09, 0.94+/-0.01, 1.00, 0.84+/-0.01, and 0.78+/-0.08, respectively. The absolute path length at 975 nm is estimated to be 3.8+/-0.6 mm, based on the intensity of the water absorptions and the known tissue water concentration. These results are strictly valid only for the experimental geometry applied here.

  4. Global flows of critical metals necessary for low-carbon technologies: the case of neodymium, cobalt, and platinum.

    PubMed

    Nansai, Keisuke; Nakajima, Kenichi; Kagawa, Shigemi; Kondo, Yasushi; Suh, Sangwon; Shigetomi, Yosuke; Oshita, Yuko

    2014-01-01

    This study, encompassing 231 countries and regions, quantifies the global transfer of three critical metals (neodymium, cobalt, and platinum) considered vital for low-carbon technologies by means of material flow analysis (MFA), using trade data (BACI) and the metal contents of trade commodities, resolving the optimization problem to ensure the material balance of the metals within each country and region. The study shows that in 2005 international trade led to global flows of 18.6 kt of neodymium, 154 kt of cobalt, and 402 t of platinum and identifies the main commodities and top 50 bilateral trade links embodying these metals. To explore the issue of consumption efficiency, the flows were characterized according to the technological level of each country or region and divided into three types: green ("efficient use"), yellow ("moderately efficient use"), and red ("inefficient use"). On this basis, the shares of green, yellow, and red flows in the aggregate global flow of Nd were found to be 1.2%, 98%, and 1.2%, respectively. For Co, the respective figures are 53%, 28%, and 19%, and for Pt 15%, 84%, and 0.87%. Furthermore, a simple indicator focusing on the composition of the three colored flows for each commodity was developed to identify trade commodities that should be prioritized for urgent technical improvement to reduce wasteful use of the metals. Based on the indicator, we discuss logical, strategic identification of the responsibilities and roles of the countries involved in the global flows.

  5. Efficient Recovery of Neodymium in Acidic System by Free-Standing Dual-Template Docking Oriented Ionic Imprinted Mesoporous Films.

    PubMed

    Zheng, Xudong; Zhang, Fusheng; Liu, Enli; Xu, Xuechao; Yan, Yongsheng

    2017-01-11

    Neodymium (Nd) is critical component of sintered neodymium magnets. Separation of Nd from consumer magnets has attracted a widespread attention. In this paper, we presented free-standing ionic imprinted mesoporous film materials for facile and highly efficient targeted separation of Nd from permanent magnets by dual-template docking oriented ionic imprinting (DTD-OII) method. DTD-OII is based on dual-template docking oriented molecular imprinting. Compared with conventional imprinting, this novel strategy does not need extra steps, but significantly advance imprinted efficiency. With optimization of functional monomer, our free-standing dual-template docking oriented ionic imprinted mesoporous films exhibit excellent adsorption of Nd by solid-liquid extraction. The Nd adsorption capacity for optimized films was 34.98 mg g(-1) under pH = 3.0. The distribution coefficient of Nd was 636 mL g(-1), which indicates films possess significantly selectivity of Nd. In addition, efficient dual-template docking oriented ionic imprinting makes films demonstrating an outstanding of reusability by cycle test, which appreciating their potential for industrial application.

  6. Effect of the addition of low rare earth elements (lanthanum, neodymium, cerium) on the biodegradation and biocompatibility of magnesium.

    PubMed

    Willbold, Elmar; Gu, Xuenan; Albert, Devon; Kalla, Katharina; Bobe, Katharina; Brauneis, Maria; Janning, Carla; Nellesen, Jens; Czayka, Wolfgang; Tillmann, Wolfgang; Zheng, Yufeng; Witte, Frank

    2015-01-01

    Rare earth elements are promising alloying element candidates for magnesium alloys used as biodegradable devices in biomedical applications. Rare earth elements have significant effects on the high temperature strength as well as the creep resistance of alloys and they improve magnesium corrosion resistance. We focused on lanthanum, neodymium and cerium to produce magnesium alloys with commonly used rare earth element concentrations. We showed that low concentrations of rare earth elements do not promote bone growth inside a 750 μm broad area around the implant. However, increased bone growth was observed at a greater distance from the degrading alloys. Clinically and histologically, the alloys and their corrosion products caused no systematic or local cytotoxicological effects. Using microtomography and in vitro experiments, we could show that the magnesium-rare earth element alloys showed low corrosion rates, both in in vitro and in vivo. The lanthanum- and cerium-containing alloys degraded at comparable rates, whereas the neodymium-containing alloy showed the lowest corrosion rates.

  7. Electrochemical extraction of neodymium by co-reduction with aluminum in LiCl-KCl molten salt

    NASA Astrophysics Data System (ADS)

    Yan, Yong-De; Xu, Yan-Lu; Zhang, Mi-Lin; Xue, Yun; Han, Wei; Huang, Ying; Chen, Qiong; Zhang, Zhi-Jian

    2013-02-01

    The electrochemical behavior of Nd(III) ions in LiCl-KCl and LiCl-KCl-AlCl3 melts on a Mo electrode at 723 K was studied by various electrochemical techniques. The results showed that Nd(III) ions are reduced to Nd(0) through two consecutive steps, and the underpotential deposition of neodymium on pre-deposited Al electrode formed two kinds of Al-Nd intermetallic compounds in LiCl-KCl-AlCl3 solutions. The electrochemical extraction of neodymium was carried out in LiCl-KCl-AlCl3 melts on a Mo electrode at 873 K by potentiostatic and galvanostatic electrolysis. The extraction efficiency was 99.25% after potentiostatic electrolysis for 30 h. Al-Li-Nd bulk alloy was obtained by galvanostatic electrolysis. X-ray diffraction (XRD) suggested that Al2Nd and Al3Nd phases were formed in Al-Li-Nd alloy. The microstructure and micro-zone chemical analysis of Al-Li-Nd alloy were characterized by scanning electron microscopy (SEM) with energy dispersive spectrometry (EDS), respectively.

  8. Cathodic processes of neodymium(iii) in LiF-NdF3-Nd2O3 melts.

    PubMed

    Huang, Chao; Liu, Xiaolong; Gao, Yuan; Liu, Shizhe; Li, Bing

    2016-08-15

    In this paper, cyclic voltammetry and square wave voltammetry are applied to characterize the cathode processes of neodymium ions on a W electrode in LiF-NdF3 melts with or without the metal Nd. The results indicate that neodymium ions in the LiF-NdF3 (2 wt%) melt are reduced in two steps, i.e. Nd(3+) → Nd(2+) and Nd(2+) → Nd(0), corresponding to starting reduction potentials of 0.35 V vs. Li(+)/Li and 0.1 V vs. Li(+)/Li, respectively. The Nd(3+) → Nd(2+) process is controlled by mass transfer and the Nd(2+) → Nd(0) process is controlled by both an interfacial step and mass transfer. But in the LiF-NdF3 melt with excess metal Nd equilibrium, the kinetics of the above two processes are controlled by mass transfer. After potentiostatic electrolysis at 0.35 V in the LiF-NdF3-Nd2O3 melt NdF2 is formed on the Mo cathode, and metallic Nd is obtained by potentiostatic electrolysis at 0.1 V in the LiF-NdF3-Nd2O3-Nd melt, which validates the above electrochemical reduction results.

  9. Superplastic Forming of Titanium Structures

    DTIC Science & Technology

    1975-04-01

    configurations. These configurations included rectangular and circular pan sections, stepped side walls, beads, joggles , and multiple parts formed at one...capability of being formed to a complex configuration with well-formed beads and Joggles , tight bend radii, and 90-degree return flanges. Since titanium...Coming operation. The configuration consists of joggles and steps positioned into the basic forming box to produce a four-cavity tool symmetrical about

  10. Free Form Low Cost Fabrication Using Titanium

    DTIC Science & Technology

    2007-06-29

    nickel-base superalloys . "* The tensile strength as an alloy of titanium can be comparable to that of lower-strength marterisitic stainless and is...better than that of austenitic or ferritic stainless. Alloys can have ultimate strengths comparable to iron base superalloys , such as A286, or cobalt...dependent on composition. Some alloy systems (titanium aluminides ) may have useful strengths above this temperature. "* The cost of titanium, while

  11. Production of titanium from ilmenite: a review

    SciTech Connect

    Kohli, R.

    1981-12-01

    The general principles for beneficiation of titanium ores are reviewed and the specific processes used in individual units in various countries are discussed. This is followed by a critical evaluation of various current and potential reduction methods for the production of titanium metal from the processed concentrates. Finally, the report outlines a research program for the development of a commercially viable alternative method for the production of titanium metal.

  12. Ultrafine-grained titanium for medical implants

    DOEpatents

    Zhu, Yuntian T.; Lowe, Terry C.; Valiev, Ruslan Z.; Stolyarov, Vladimir V.; Latysh, Vladimir V.; Raab, Georgy J.

    2002-01-01

    We disclose ultrafine-grained titanium. A coarse-grained titanium billet is subjected to multiple extrusions through a preheated equal channel angular extrusion (ECAE) die, with billet rotation between subsequent extrusions. The resulting billet is cold processed by cold rolling and/or cold extrusion, with optional annealing. The resulting ultrafine-grained titanium has greatly improved mechanical properties and is used to make medical implants.

  13. Recovery of titanium values from titanium grinding swarf by electric furnace smelting

    SciTech Connect

    Gerdemann, S.J.; White, J.C.

    1999-10-19

    A method for the recovery of valuable materials from titanium grinding swarf is provided comprising the steps of sieving the accumulated titanium grinding swarf to remove unwanted coarse trash and grinding wheel fragments, pelletizing, and smelting in an electric arc furnace to produce ferrotitanium and/or high titanium slag.

  14. Recovery of titanium values from titanium grinding swarf by electric furnace smelting

    DOEpatents

    Gerdemann, Stephen J.; White, Jack C.

    1998-01-01

    A method for the recovery of valuable materials from titanium grinding swarf is provided comprising the steps of sieving the accumulated titanium grinding swarf to remove unwanted coarse trash and grinding wheel fragments, pelletizing, and smelting in an electric arc furnace to produce ferrotitanium and/or high titanium slag.

  15. Recovery of titanium values from titanium grinding swarf by electric furnace smelting

    DOEpatents

    Gerdemann, Stephen J.; White, Jack C.

    1999-01-01

    A method for the recovery of valuable materials from titanium grinding swarf is provided comprising the steps of sieving the accumulated titanium grinding swarf to remove unwanted coarse trash and grinding wheel fragments, pelletizing, and smelting in an electric arc furnace to produce ferrotitanium and/or high titanium slag.

  16. Recovery of titanium values from titanium grinding swarf by electric furnace smelting

    DOEpatents

    Gerdemann, S.J.; White, J.C.

    1998-08-04

    A method for the recovery of valuable materials from titanium grinding swarf is provided comprising the steps of sieving the accumulated titanium grinding swarf to remove unwanted coarse trash and grinding wheel fragments, pelletizing, and smelting in an electric arc furnace to produce ferrotitanium and/or high titanium slag. 1 fig.

  17. Reduction of titanium dioxide to metallic titanium conducted under the autogenic pressure of the reactants.

    PubMed

    Eshed, Michal; Irzh, Alexander; Gedanken, Aharon

    2009-08-03

    We report on a reaction to convert titanium dioxide to titanium. The reduction reaction was done under the autogenic pressure of the reactants at 750 degrees C for 5 h. The MgO, a by-product, was removed by acids to obtain pure metallic titanium.

  18. A composite nanostructured electron-transport layer for stable hole-conductor free perovskite solar cells: design and characterization

    NASA Astrophysics Data System (ADS)

    Yu, Zhenhua; Qi, Fei; Liu, Pei; You, Sujian; Kondamareddy, Kiran Kumar; Wang, Changlei; Cheng, Nian; Bai, Sihang; Liu, Wei; Guo, Shishang; Zhao, Xing-Zhong

    2016-03-01

    A novel composite nanostructured titanium dioxide (TiO2) based electron-transport layer (ETL) is designed by combining size blended nanoparticles (SBNP) and nanoarrays (NA) for efficient perovskite solar cell (PSC) applications. The composite nanostructured (SBNP + NA) ETL is successfully employed in hole-conductor free PSCs, there by achieving a stable device with a maximum efficiency of 13.5%. The improvement in the performance is attributed to the better charge transport and lower recombination in the SBNP + NA ETL. Despite the stable high efficiency, SBNP + NA ETL based PSCs are advantageous owing to their low cost, ease of all-solution fabrication process in an open environment and good reproducibility.A novel composite nanostructured titanium dioxide (TiO2) based electron-transport layer (ETL) is designed by combining size blended nanoparticles (SBNP) and nanoarrays (NA) for efficient perovskite solar cell (PSC) applications. The composite nanostructured (SBNP + NA) ETL is successfully employed in hole-conductor free PSCs, there by achieving a stable device with a maximum efficiency of 13.5%. The improvement in the performance is attributed to the better charge transport and lower recombination in the SBNP + NA ETL. Despite the stable high efficiency, SBNP + NA ETL based PSCs are advantageous owing to their low cost, ease of all-solution fabrication process in an open environment and good reproducibility. Electronic supplementary information (ESI) available: Details of the experimental section and ESI figures. See DOI: 10.1039/c5nr09045h

  19. Visible Spectra of Titanium Dioxide

    NASA Astrophysics Data System (ADS)

    Gupta, V.; Nagarajan, R.; Maier, J. P.; Zhuang, X.; Le, A.; Steimle, T. C.

    2011-05-01

    Titanium oxide (TiO) has been extensively studied spectroscopically due to its astrophysical relevance. TiO is the main opacity source in the atmospheres of cool M-type stars in the visible and near infrared. In view of the high cosmic abundance of Ti and O, titanium dioxide (TiO2) is believed to play an important role in dust formation processes from the gas-phase in circumstellar shells of oxygen-rich stars. The electronic spectra of a cold molecular beam of TiO2 have been investigated using mass-resolved resonance enhanced multi-photon ionization and laser induced fluorescence spectroscopy. TiO2 was produced by laser ablation of a pure titanium rod in the presence of a supersonic expanding mixture of approximately 5% O2 in either helium or argon. The spectra were recorded in the region 17500 cm-1 to 22500 cm-1 and the bands assigned to the A1B2 ← X1A1 transition. The origin and harmonic vibrational constants for the A1B2 state were determined to be: T000 = 17593(5) cm-1, ω1 = 876(3) cm-1, ω2 = 184(1) cm-1, and ω3 = 316(2) cm-1. Further, the dispersed fluorescence of a few bands were recorded to obtain vibrational parameters for the X1A1 state.

  20. Alternative nanostructures for thermophones

    NASA Astrophysics Data System (ADS)

    Mayo, Nathanael; Aliev, Ali; Baughman, Ray

    2015-03-01

    There is a large promise for thermophones in high power sonar arrays, flexible loudspeakers, and noise cancellation devices. So far, freestanding aerogel-like carbon nanotube sheets demonstrate the best performance as a thermoacoustic heat source. However, the limited accessibility of large size freestanding carbon nanotube sheets and other even more exotic materials published recently, hampers the field. We present here new alternative materials for a thermoacoustic heat source with high energy conversion efficiency, additional functionalities, environmentally friendly and cost effective production technologies. We discuss the thermoacoustic performance of alternative nanoscale materials and compare their spectral and power dependencies of sound pressure in air. The study presented here focuses on engineering thermal gradients in the vicinity of nanostructures and subsequent heat dissipation processes from the interior of encapsulated thermoacoustic projectors. Applications of thermoacoustic projectors for high power SONAR arrays, sound cancellation, and optimal thermal design, regarding enhanced energy conversion efficiency, are discussed.

  1. Welded Permanent Fittings for Titanium Hydraulic Tubing.

    DTIC Science & Technology

    FITTINGS, *HYDRAULIC EQUIPMENT, RIVETED JOINTS, TITANIUM ALLOYS, PIPES , JET TRANSPORT AIRCRAFT, COLD WORKING, PRESSURE, RUPTURE, ARC WELDING , INERT...GAS WELDING , RADIOGRAPHY, STRESS RELIEVING, SUPERSONIC AIRCRAFT, COMMERCIAL AIRCRAFT.

  2. Method for producing titanium aluminide weld rod

    DOEpatents

    Hansen, Jeffrey S.; Turner, Paul C.; Argetsinger, Edward R.

    1995-01-01

    A process for producing titanium aluminide weld rod comprising: attaching one end of a metal tube to a vacuum line; placing a means between said vacuum line and a junction of the metal tube to prevent powder from entering the vacuum line; inducing a vacuum within the tube; placing a mixture of titanium and aluminum powder in the tube and employing means to impact the powder in the tube to a filled tube; heating the tube in the vacuum at a temperature sufficient to initiate a high-temperature synthesis (SHS) reaction between the titanium and aluminum; and lowering the temperature to ambient temperature to obtain a intermetallic titanium aluminide alloy weld rod.

  3. Repairable, nanostructured biomimetic hydrogels

    NASA Astrophysics Data System (ADS)

    Firestone, M.; Brombosz, S.; Grubjesic, S.

    2013-03-01

    Proteins facilitate many key cellular processes, including signal recognition and energy transduction. The ability to harness this evolutionarily-optimized functionality could lead to the development of protein-based systems useful for advancing alternative energy storage and conversion. The future of protein-based, however, requires the development of materials that will stabilize, order and control the activity of the proteins. Recently we have developed a synthetic approach for the preparation of a durable biomimetic chemical hydrogel that can be reversibly swollen in water. The matrix has proven ideal for the stable encapsulation of both water- and membrane-soluble proteins. The material is composed of an aqueous dispersion of a diacrylate end-derivatized PEO-PPO-PEO macromer, a saturated phospholipid and a zwitterionic co-surfactant that self-assembles into a nanostructured physical gel at room temperature as determined by X-ray scattering. The addition of a water soluble PEGDA co-monomer and photoinitator does not alter the self-assembled structure and UV irradiation serves to crosslink the acrylate end groups on the macromer with the PEGDA forming a network within the aqueous domains as determined by FT-IR. More recently we have begun to incorporate reversible crosslinks employing Diels-Alder chemistry, allowing for the extraction and replacement of inactive proteins. The ability to replenish the materials with active, non-denatured forms of protein is an important step in advancing these materials for use in nanostructured devices This work was supported by the Office of Basic Energy Sciences, Division of Materials Sciences, USDoE under Contract No. DE-AC02-06CH11357.

  4. @AuAg nanostructures

    NASA Astrophysics Data System (ADS)

    Singh, Rina; Soni, R. K.

    2014-09-01

    Bimetallic and trimetallic nanoparticles have attracted significant attention in recent times due to their enhanced electrochemical and catalytic properties compared to monometallic nanoparticles. The numerical calculations using Mie theory has been carried out for three-layered metal nanoshell dielectric-metal-metal (DMM) system consisting of a particle with a dielectric core (Al@Al2O3), a middle metal Ag (Au) layer and an outer metal Au (Ag) shell. The results have been interpreted using plasmon hybridization theory. We have also prepared Al@Al2O3@Ag@Au and Al@Al2O3@AgAu triple-layered core-shell or alloy nanostructure by two-step laser ablation method and compared with calculated results. The synthesis involves temporal separations of Al, Ag, and Au deposition for step-by-step formation of triple-layered core-shell structure. To form Al@Ag nanoparticles, we ablated silver for 40 min in aluminium nanoparticle colloidal solution. As aluminium oxidizes easily in water to form alumina, the resulting structure is core-shell Al@Al2O3. The Al@Al2O3 particle acts as a seed for the incoming energetic silver particles for multilayered Al@Al2O3@Ag nanoparticles is formed. The silver target was then replaced by gold target and ablation was carried out for different ablation time using different laser energy for generation of Al@Al2O3@Ag@Au core-shell or Al@Al2O3@AgAu alloy. The formation of core-shell and alloy nanostructure was confirmed by UV-visible spectroscopy. The absorption spectra show shift in plasmon resonance peak of silver to gold in the range 400-520 nm with increasing ablation time suggesting formation of Ag-Au alloy in the presence of alumina particles in the solution.

  5. Surfactant free most probable TiO2 nanostructures via hydrothermal and its dye sensitized solar cell properties

    PubMed Central

    Mali, Sawanta S.; Kim, Hyungjin; Shim, Chang Su; Patil, Pramod S.; Kim, Jin Hyeok; Hong, Chang Kook

    2013-01-01

    Tailoring the nano-morphology and nano-architecture of titanium dioxide (TiO2) is the most important task in the third generation solar cells (Dye sensitized solar cells/Quantum dot sensitized solar cells) (DSSCs/QDSSCs). In this article we present complete study of surfactant free synthesis of TiO2 nanostructures by a simple and promising hydrothermal route. The plethora of nanostructures like nanoparticles clusters, 1D tetragonal nanorods, 3D dendrites containing nanorods having <30 nm diameter and 3D hollow urchin like have been synthesized. These nanostructures possess effective large surface area and thus useful in DSSCs. In the present work, 7.16% power conversion efficiency has been demonstrated for 3D dendritic hollow urchin like morphology. Our synthetic strategy provides an effective solution for surfactant free synthesis of efficient TiO2 nanoarchitectures. PMID:24141599

  6. Nanostructured Materials for Renewable Energy

    SciTech Connect

    2009-11-01

    This factsheet describes a research project whose overall objective is to advance the fundamental understanding of novel photoelectronic organic device structures integrated with inorganic nanostructures, while also expanding the general field of nanomaterials for renewable energy devices and systems.

  7. Microscopic characterization of peptide nanostructures.

    PubMed

    Mammadov, Rashad; Tekinay, Ayse B; Dana, Aykutlu; Guler, Mustafa O

    2012-02-01

    Peptide-based nanomaterials have been utilized for various applications from regenerative medicine to electronics since they provide several advantages including easy synthesis methods, numerous routes for functionalization and biomimicry of secondary structures of proteins which leads to design of self-assembling peptide molecules to form nanostructures. Microscopic characterization at nanoscale is critical to understand processes directing peptide molecules to self-assemble and identify structure-function relationship of the nanostructures. Here, fundamental studies in microscopic characterization of peptide nanostructures are discussed to provide insights in widely used microscopy tools. In this review, we will encompass characterization studies of peptide nanostructures with modern microscopes, such as TEM, SEM, AFM, and advanced optical microscopy techniques. We will also mention specimen preparation methods and describe interpretation of the images.

  8. Neodymium diffusion in orthopyroxene: Experimental studies and applications to geological and planetary problems

    NASA Astrophysics Data System (ADS)

    Sano, Jennifer; Ganguly, Jibamitra; Hervig, Richard; Dohmen, Ralf; Zhang, Xiaoyu

    2011-08-01

    resetting of the Sm-Nd mineral age by an "impulsive disturbance" [Prinzhoffer A, Papanastassiou D.A, Wasserburg G.J., 1992. Samarium-neodymium evolution of meteorites. Geochim. Cosmochim. Acta 56, 797-815].

  9. Rare earth elements and neodymium isotopes in world river sediments revisited

    NASA Astrophysics Data System (ADS)

    Bayon, G.; Toucanne, S.; Skonieczny, C.; André, L.; Bermell, S.; Cheron, S.; Dennielou, B.; Etoubleau, J.; Freslon, N.; Gauchery, T.; Germain, Y.; Jorry, S. J.; Ménot, G.; Monin, L.; Ponzevera, E.; Rouget, M.-L.; Tachikawa, K.; Barrat, J. A.

    2015-12-01

    Over the past decades, rare earth elements (REE) and their radioactive isotopes have received tremendous attention in sedimentary geochemistry, as tracers for the geological history of the continental crust and provenance studies. In this study, we report on elemental concentrations and neodymium (Nd) isotopic compositions for a large number of sediments collected near the mouth of rivers worldwide, including some of the world's major rivers. Sediments were leached for removal of non-detrital components, and both clay and silt fractions were retained for separate geochemical analyses. Our aim was to re-examine, at the scale of a large systematic survey, whether or not REE and Nd isotopes could be fractionated during Earth surface processes. Our results confirmed earlier assumptions that river sediments do not generally exhibit any significant grain-size dependent Nd isotopic variability. Most sediments from rivers draining old cratonic areas, sedimentary systems and volcanic provinces displayed similar Nd isotopic signatures in both clay and silt fractions, with ΔεNd(clay-silt) < |1|. A subtle decoupling of Nd isotopes between clays and silts was identified however in a few major river systems (e.g. Nile, Mississippi, Fraser), with clays being systematically shifted towards more radiogenic values. This observation suggests that preferential weathering of volcanic and/or sedimentary rocks relative to more resistant lithologies may occur in river basins, possibly leading locally to Nd isotopic decoupling between different size fractions. Except for volcanogenic sediments, silt fractions generally displayed homogeneous REE concentrations, exhibiting relatively flat shale-normalized patterns. However, clay fractions were almost systematically characterized by a progressive enrichment from the heavy to the light REE and a positive europium (Eu) anomaly. In agreement with results from previous soil investigations, the observed REE fractionation between clays and silts

  10. Neodymium isotopes in biogenic carbonates: reliable archives of ɛNd

    NASA Astrophysics Data System (ADS)

    Montagna, P.; Goldstein, S. L.; Taviani, M.; Frank, N.; McCulloch, M. T.

    2010-12-01

    Neodymium isotope (143Nd/144Nd) compositions from dispersed authigenic ferromanganese oxide fraction in marine sediments, ferromanganese crusts, foraminiferal shells and fossil fish teeth are employed to trace provenance and water mass mixing in the past, having the advantage of not being fractionated by biological processes in the water column. In the modern ocean the different water masses ultimately derive their ɛNd values through continental weathering, erosion and particle-seawater interactions. This geochemical tracer has been only recently applied to scleractinian deep-water coral skeletons sourced from various sites and depths in the Atlantic ocean. Aragonitic corals can be precisely dated by U-series, potentially providing century-long records of intermediate and bathyal zone variability at sub-decadal resolution. Motivated by these recent findings we have investigated the Nd isotopic compositions of living specimens of various calcifying organisms collected in two key locations of the Mediterranean Sea and in the Southern Ocean. In particular, we analyzed several specimens of the aragonitic deep-water corals Desmophyllum dianthus, Lophelia pertusa, Madrepora oculata, Flabellum impensum, the temperate coral Cladocora caespitosa, the calcitic gorgonian coral Corallium rubrum, the bivalves Glans aculeata and Karnekampia bruei and the polychate Serpula vermicularis. Most of the samples were retrieved from the Strait of Sicily and the Southern Adriatic Sea at different water depths. Ten seawater samples from three new profiles in the Mediterranean were also collected at the same locations and depths, offering a unique opportunity to compare the Nd isotopic composition of biogenic carbonates directly with the surrounding ambient seawater. The Mediterranean Sea is particularly suited for this comparison exercise since it is characterized by water masses displaying a large range of ɛNd values, from -10.5 in the Western Mediterranean to -4.8 in the Eastern

  11. The influence of surface modification on bacterial adhesion to titanium-based substrates.

    PubMed

    Lorenzetti, Martina; Dogša, Iztok; Stošicki, Tjaša; Stopar, David; Kalin, Mitjan; Kobe, Spomenka; Novak, Saša

    2015-01-28

    This study examines bacterial adhesion on titanium-substrates used for bone implants. Adhesion is the most critical phase of bacterial colonization on medical devices. The surface of titanium was modified by hydrothermal treatment (HT) to synthesize nanostructured TiO2-anatase coatings, which were previously proven to improve corrosion resistance, affect the plasma protein adsorption, and enhance osteogenesis. The affinity of the anatase coatings toward bacterial attachment was studied by using a green fluorescent protein-expressing Escherichia coli (gfp-E. coli) strain in connection with surface photoactivation by UV irradiation. We also analyzed the effects of surface topography, roughness, charge, and wettability. The results suggested the dominant effects of the macroscopic surface topography, as well as microasperity at the surface roughness scale, which were produced during titanium machining, HT treatment, or both. Macroscopic grooves provided a preferential site for bacteria deposit within the valleys, while the microscopic roughness of the valleys determined the actual interaction surface between bacterium and substrate, resulting in an "interlocking" effect and undesired high bacterial adhesion on nontreated titanium. In the case of TiO2-coated samples, the nanocrystals reduced the width between the microasperities and thus added nanoroughness features. These factors decreased the contact area between the bacterium and the coating, with consequent lower bacterial adhesion (up to 50% less) in comparison to the nontreated titanium. On the other hand, the pronounced hydrophilicity of one of the HT-coated discs after pre-irradiation seemed to enhance the attachment of bacteria, although the increase was not statistically significant (p > 0.05). This observation may be explained by the acquired similar degree of wetting between gfp-E. coli and the coating. No correlation was found between the bacterial adhesion and the ζ-values of the samples in PBS, so the

  12. From the subtropics to the equator in the Southwest Pacific: Continental material fluxes quantified using neodymium data along modeled thermocline water pathways

    NASA Astrophysics Data System (ADS)

    Grenier, Mélanie; Jeandel, Catherine; Cravatte, Sophie

    2014-06-01

    The southwestern tropical Pacific, part of a major pathway for waters feeding the Equatorial Undercurrent, is a region of important geochemical enrichment through land-ocean boundary exchange. Here we develop an original method based on the coupling between dynamical modeling and geochemical tracer data to identify regions of enrichment along the water pathways from the subtropics to the equator, and to allow a refined quantification of continental material fluxes. Neodymium data are interpreted with the help of modeled Lagrangian trajectories of an Ocean General Circulation Model. We reveal that upper and lower thermocline waters have different pathways together with different geochemical evolutions. The upper thermocline waters entering the Solomon Sea mainly originate from the central subtropical gyre, enter the Coral Sea in the North Vanuatu Jet and likely receive radiogenic neodymium from the basaltic island margins encountered along their route. The lower thermocline waters entering the Solomon Sea mainly originate from northeast of New Zealand and enter the Coral Sea in the North Caledonian Jet. Depletion of their neodymium content likely occurs when flowing along the Australian and Papua coasts. Downstream from the Solomon Sea, waters flowing along the Papua New Guinea margins near the Sepik river mouth become surprisingly depleted in their neodymium content in the upper thermocline while enriched in the lower thermocline. This coupled approach is proposed as strong support to interpret the origin of the equatorial Pacific natural fertilization through a better understanding of the circulation, important objectives of the international GEOTRACES and SPICE programs, respectively.

  13. Enantiomeric NMR signal separation behavior and mechanism of samarium(III) and neodymium(III) complexes with (S,S)-ethylenediamine-N,N'-disuccinate.

    PubMed

    Aizawa, Sen-Ichi; Okano, Masaru; Kidani, Takahiro

    2017-04-12

    Enantiomeric (1) H and (13) C NMR signal separation behaviors of various α-amino acids and DL-tartarate were investigated by using the samarium(III) and neodymium(III) complexes with (S,S)-ethylenediamine-N,N'-disuccinate as chiral shift reagents. A relatively smaller concentration ratio of the lanthanide(III) complex to substrates was suitable for the neodymium(III) complex compared with the samarium(III) one, striking a balance between relatively greater signal separation and broadening. To clarify the difference in the signal separation behavior, the chemical shifts of β-protons for fully bound D- and L-alanine (δb (D) and δb (L)) and their adduct formation constants (Ks) were obtained for both metal complexes. Preference for D-alanine was similarly observed for both complexes, while it was revealed that the difference between the δb (D) and δb (L) values is the significant factor to determine the enantiomeric signal separation. The neodymium(III) and samarium(III) complexes can be used complementarily for higher and smaller concentration ranges of substrates, respectively, because the neodymium(III) complex gives the larger difference between the δb (D) and δb (L) values with greater signal broadening compared to the samarium(III) complex.

  14. Characterization of Nanostructured Polymer Films

    DTIC Science & Technology

    2014-12-23

    of the film for complete polymer chain relaxation, including relaxation of surface features . The presence of intact surface globules at a substrate...AFRL-OSR-VA-TR-2015-0059 Characterization of Nanostructured Polymer Films RODNEY PRIESTLEY TRUSTEES OF PRINCETON UNIVERSITY Final Report 12/23/2014...Report 3. DATES COVERED (From - To) 06/01/2012-08/31/2014 4. TITLE AND SUBTITLE Characterization of Nanostructured Polymer Films 5a. CONTRACT

  15. Nanostructure-induced DNA condensation

    NASA Astrophysics Data System (ADS)

    Zhou, Ting; Llizo, Axel; Wang, Chen; Xu, Guiying; Yang, Yanlian

    2013-08-01

    The control of the DNA condensation process is essential for compaction of DNA in chromatin, as well as for biological applications such as nonviral gene therapy. This review endeavours to reflect the progress of investigations on DNA condensation effects of nanostructure-based condensing agents (such as nanoparticles, nanotubes, cationic polymer and peptide agents) observed by using atomic force microscopy (AFM) and other techniques. The environmental effects on structural characteristics of nanostructure-induced DNA condensates are also discussed.

  16. Microwave method for synthesis of micro- and nanostructures with controllable composition during gyrotron discharge

    NASA Astrophysics Data System (ADS)

    Batanov, German M.; Borzosekov, Valentin D.; Golberg, Dmitri; Iskhakova, Ludmila D.; Kolik, Leonid V.; Konchekov, Evgeny M.; Kharchev, Nikolai K.; Letunov, Alexander A.; Malakhov, Dmitry V.; Milovich, Filipp O.; Obraztsova, Ekaterina A.; Petrov, Alexander E.; Ryabikina, Irina G.; Sarksian, Karen A.; Stepakhin, Vladimir D.; Skvortsova, Nina N.

    2016-01-01

    We introduce an approach toward the synthesis of micro- and nanostructures under nonequilibrium microwave discharges within metal-dielectric powder mixtures induced by powerful microwave gyrotron radiation. A new plasma-chemical reactor capable of sustaining a discharge regime with an afterglow phase of an order of magnitude longer than the gyrotron pulse duration was constructed for these experiments. In the nonequilibrium conditions of such a discharge, plasma-induced exothermic chemical reactions leading to the synthesis of various compounds were initiated. The synthesized structures were deposited on the reactor walls and on the impurity particles within the reactor. This method was tested under gyrotron-initiated discharges within various metal-dielectric powder mixtures of titanium-boron, molybdenum-boron, titanium-silicon-boron, molybdenum-boron nitride, molybdenum-tungsten-boron nitride, and so on. Depending on the powder mixture composition, reactor atmosphere, and other parameters, micro- and nanosized particles of boron nitride, titanium diboride, molybdenum boride, titanium boride, molybdenum, and molybdenum oxide, were synthesized, detected, and analyzed.

  17. Composite thin-foil bandpass filter for EUV astronomy Titanium-antimony-titanium

    NASA Technical Reports Server (NTRS)

    Jelinsky, P.; Martin, C.; Kimble, R.; Bowyer, S.; Steele, G.

    1983-01-01

    Thin metallic foils of antimony and titanium have been investigated in an attempt to develop an EUV filter with a bandpass from 350 to 550 A. A composite filter has been developed composed of antimony sandwiched between two titanium foils. The transmissions of sample composite foils and of pure titanium foils from 130 to 1216 A are presented. The absorption coefficients of anatimony and titanium and the effect of titanium oxide on the transmission are derived. The composite filter has been found to be quite stable and mechanically rugged. Among other uses, the filter shows substantial promise for EUV astronomy.

  18. Tribological evaluation of diamond coating on pure titanium in comparison with plasma nitrided titanium and uncoated titanium

    SciTech Connect

    Yan, B.; Loh, N.L.; Fu, Y.; Sun, C.Q.; Hing, P.

    1999-12-01

    Titanium alloys are characterized by poor tribological properties, and the traditional use of titanium alloys has been restricted to nontribological applications. The deposition of a well adherent diamond coating is a promising way to solve this problem. In this study, the tribological properties of diamond-coated titanium were studied using a pin-on-disk tribometer, and the results were compared with those of pure titanium and plasma nitrided titanium. The tribological behavior of pure titanium was characterized by high coefficient of friction and rapid wear of materials. Plasma nitriding improved the wear resistance only under low normal load; however, this hardened layer was not efficient in improving the wear resistance and the friction properties under high normal load. Diamond coating on pure titanium improved the wear resistance of titanium significantly. Surface profilometry measurement indicated that little or no wear of the diamond coating occurred under the test conditions loads. The roughness of the diamond coating was critical because it controlled the amount of abrasive damage on the counterface. Reducing the surface roughness by polishing led to the reductions in both the friction and wear of the counterface.

  19. Analysis of x-ray diffraction pattern and complex plane impedance plot of polypyrrole/titanium dioxide nanocomposite: A simulation study

    NASA Astrophysics Data System (ADS)

    Ravikiran, Y. T.; Vijaya Kumari, S. C.

    2013-06-01

    To innovate the properties of Polypyrrole/Titanium dioxide (PPy/TiO2) nanocomposite further, it has been synthesized by chemical polymerization technique. The nanostructure and monoclinic phase of the prepared composite have been confirmed by simulating the X-ray diffraction pattern (XRD). Also, complex plane impedance plot of the composite has been simulated to find equivalent resistance capacitance circuit (RC circuit) and numerical values of R and C have been predicted.

  20. ATOMIC LAYER DEPOSITION OF TITANIUM OXIDE THIN FILMS ONNANOPOROUS ALUMINA TEMPLATES FOR MEDICAL APPLICATIONS

    SciTech Connect

    Brigmon, R.

    2009-05-05

    Nanostructured materials may play a significant role in controlled release of pharmacologic agents for treatment of cancer. Many nanoporous polymer materials are inadequate for use in drug delivery. Nanoporous alumina provides several advantages over other materials for use in controlled drug delivery and other medical applications. Atomic layer deposition was used to coat all the surfaces of the nanoporous alumina membrane in order to reduce the pore size in a controlled manner. Both the 20 nm and 100 nm titanium oxide-coated nanoporous alumina membranes did not exhibit statistically lower viability compared to the uncoated nanoporous alumina membrane control materials. In addition, 20 nm pore size titanium oxide-coated nanoporous alumina membranes exposed to ultraviolet light demonstrated activity against Escherichia coli and Staphylococcus aureus bacteria. Nanostructured materials prepared using atomic layer deposition may be useful for delivering a pharmacologic agent at a precise rate to a specific location in the body. These materials may serve as the basis for 'smart' drug delivery devices, orthopedic implants, or self-sterilizing medical devices.