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Sample records for oxynitrates

  1. The Oxynitration of Benzene to Nitrophenols

    DTIC Science & Technology

    1945-10-05

    27 dtd 24-28 Jun 1946; OTS index dtd Jun 1947 Reproduced by AIR DOCUMENTS DIVISION ♦ 4 t i ° HEADQUARTERS AIR MATERIEL COMMAND WRIGHT...Picatinney Arsenal, but «ere discontinued in 1921 because the results indicated that the consumption of nitric acid would be high and that costly...o- BNB Dinitrobenzene = DNB o-Nitrophenol * o-NP p-Nitrophenol * p-NP Nitrobenzene = NB 2,4,2«,4’-Tetra- nitrodiphenylamine ■ TNDA I. THE

  2. Neurotoxicity From Chronic Exposure to Depleted Utanium

    DTIC Science & Technology

    2005-04-01

    Technologies, San Antonio, TX) or uranium (VI) oxide (Ultra Scientific, North Kingstown, RI) at concentrations ranging from 10-3. 5 to 10-8 M. 200pt of...system described above possesses sufficient sensitivity to measure these latter concentrations. The presence of uranium (VI) oxide or uranium oxynitrate...systematically alter these response magnitudes. This suggests that UO2 +2 does not possess Ca 2-mimetic properties, but it could also be explained if

  3. Multilayered thermal insulation formed of zirconia bonded layers of zirconia fibers and metal oxide fibers and method for making same

    DOEpatents

    Wrenn, G.E. Jr.; Holcombe, C.E. Jr.

    1988-09-13

    A multilayered thermal insulating composite is formed of a first layer of zirconia-bonded zirconia fibers for utilization near the hot phase or surface of a furnace or the like. A second layer of zirconia-bonded metal oxide fibers is attached to the zirconia fiber layer by a transition layer formed of intermingled zirconia fibers and metal oxide fibers. The thermal insulation is fabricated by vacuum molding with the layers being sequentially applied from aqueous solutions containing the fibers to a configured mandrel. A portion of the solution containing the fibers forming the first layer is intermixed with the solution containing the fibers of the second layer for forming the layer of mixed fibers. The two layers of fibers joined together by the transition layer are saturated with a solution of zirconium oxynitrate which provides a zirconia matrix for the composite when the fibers are sintered together at their nexi.

  4. Multilayered thermal insulation formed of zirconia bonded layers of zirconia fibers and metal oxide fibers and method for making same

    DOEpatents

    Wrenn, Jr., George E.; Holcombe, Jr., Cressie E.

    1988-01-01

    A multilayered thermal insulating composite is formed of a first layer of zirconia-bonded zirconia fibers for utilization near the hot phase or surface of a furnace or the like. A second layer of zirconia-bonded metal oxide fibers is attached to the zirconia fiber layer by a transition layer formed of intermingled zirconia fibers and metal oxide fibers. The thermal insulation is fabricated by vacuum molding with the layers being sequentially applied from aqueous solutions containing the fibers to a configured mandrel. A portion of the solution containing the fibers forming the first layer is intermixed with the solution containing the fibers of the second layer for forming the layer of mixed fibers. The two layers of fibers joined together by the transition layer are saturated with a solution of zirconium oxynitrate which provides a zirconia matrix for the composite when the fibers are sintered together at their nexi.

  5. Influence of starting precursors and synthesis methods on the physiochemical properties of zirconia

    SciTech Connect

    Gaydhankar, T.R.; Jha, R.K.; Nikalje, M.D.; Waghmare, K.J.

    2014-07-01

    Graphical abstract: Crystallite size of tetragonal phase of the zirconia samples prepared using different synthesis parameters and precursors as a function of calcination temperature. Surface area values of the zirconia samples calcined at 500 and 700 °C are in given brackets. - Highlights: • Zirconia prepared with modified sol–gel method is less stable compared with zirconia prepared by precipitation method. • Optimized synthesis conditions shifted the glow exotherm to higher temperature range indicating better thermal stability. • Tetragonal-zirconia could be synthesized in cost-effective manner using zirconium oxy-nitrate. • In our studies no co-relation between the surface area and crystallite size was observed. - Abstract: Under identical and judiciously pre-optimized synthesis conditions, the influence of different combinations of zirconium sources and/or post treatment conditions on structural properties, thermal stability, phase composition and morphology of zirconia has been investigated. High surface area tetragonal zirconia could be synthesized in a cost-effective manner from 1 M solution of zirconium oxy-nitrate at pH 11 using aqueous ammonia solution as a precipitant when calcined at 400 °C for 3 h. Irrespective of the preparation method, pH and starting precursor, zirconia samples prepared without digestion contained dominant monoclinic phase with some traces of tetragonal phase when calcined at 700 °C. Even though there is linear decrease in surface area with increase in the crystallite size for each sample as a function of calcination temperature, no co-relation between the surface area and crystallite size could be achieved. SEM images show agglomerated and irregular shape particles between 10 to 20 μm.

  6. Zirconium ions up-regulate the BMP/SMAD signaling pathway and promote the proliferation and differentiation of human osteoblasts.

    PubMed

    Chen, Yongjuan; Roohani-Esfahani, Seyed-Iman; Lu, ZuFu; Zreiqat, Hala; Dunstan, Colin R

    2015-01-01

    Zirconium (Zr) is an element commonly used in dental and orthopedic implants either as zirconia (ZrO2) or in metal alloys. It can also be incorporated into calcium silicate-based ceramics. However, the effects of in vitro culture of human osteoblasts (HOBs) with soluble ionic forms of Zr have not been determined. In this study, primary culture of human osteoblasts was conducted in the presence of medium containing either ZrCl4 or Zirconium (IV) oxynitrate (ZrO(NO3)2) at concentrations of 0, 5, 50 and 500 µM, and osteoblast proliferation, differentiation and calcium deposition were assessed. Incubation of human osteoblast cultures with Zr ions increased the proliferation of human osteoblasts and also gene expression of genetic markers of osteoblast differentiation. In 21 and 28 day cultures, Zr ions at concentrations of 50 and 500 µM increased the deposition of calcium phosphate. In addition, the gene expression of BMP2 and BMP receptors was increased in response to culture with Zr ions and this was associated with increased phosphorylation of SMAD1/5. Moreover, Noggin suppressed osteogenic gene expression in HOBs co-treated with Zr ions. In conclusion, Zr ions appear able to induce both the proliferation and the differentiation of primary human osteoblasts. This is associated with up-regulation of BMP2 expression and activation of BMP signaling suggesting this action is, at least in part, mediated by BMP signaling.

  7. Zirconium Ions Up-Regulate the BMP/SMAD Signaling Pathway and Promote the Proliferation and Differentiation of Human Osteoblasts

    PubMed Central

    Chen, Yongjuan; Roohani-Esfahani, Seyed-Iman; Lu, ZuFu; Zreiqat, Hala; Dunstan, Colin R.

    2015-01-01

    Zirconium (Zr) is an element commonly used in dental and orthopedic implants either as zirconia (ZrO2) or in metal alloys. It can also be incorporated into calcium silicate-based ceramics. However, the effects of in vitro culture of human osteoblasts (HOBs) with soluble ionic forms of Zr have not been determined. In this study, primary culture of human osteoblasts was conducted in the presence of medium containing either ZrCl4 or Zirconium (IV) oxynitrate (ZrO(NO3)2) at concentrations of 0, 5, 50 and 500 µM, and osteoblast proliferation, differentiation and calcium deposition were assessed. Incubation of human osteoblast cultures with Zr ions increased the proliferation of human osteoblasts and also gene expression of genetic markers of osteoblast differentiation. In 21 and 28 day cultures, Zr ions at concentrations of 50 and 500 µM increased the deposition of calcium phosphate. In addition, the gene expression of BMP2 and BMP receptors was increased in response to culture with Zr ions and this was associated with increased phosphorylation of SMAD1/5. Moreover, Noggin suppressed osteogenic gene expression in HOBs co-treated with Zr ions. In conclusion, Zr ions appear able to induce both the proliferation and the differentiation of primary human osteoblasts. This is associated with up-regulation of BMP2 expression and activation of BMP signaling suggesting this action is, at least in part, mediated by BMP signaling. PMID:25602473

  8. Synthesis of Pu-Doped Ceramic

    SciTech Connect

    Anderson, E. B

    1998-09-02

    Plutonium-doped zircon containing about 10 wt% Pu was synthesized in this cooperative project between Russia and the United States conducted at the V. G. Khlopin Radium Institute. The sol-gel method was used for starting precursor preparation to provide complete mixing of initial components and to avoid dust formation inside the glove-box. The sol-gel process also gives interim Pu stabilization in the form of amorphous zirconium hydrosilicate (AZHS), which is a result of gel solidification. AZHS is a solid and relatively durable material that can be easy converted into crystalline zircon by pressureless sintering, thus avoiding significant radioactive contamination of laboratory equipment. A methanol-aqueous solution of tetraethoxysilane Si(OC2H5)4, Pu-nitrate, and zirconil oxynitrate was prepared in final stoichiometry of zircon (Zr,Pu)SiO4 80 wt% + zirconia (Zr,Pu)O2 20 wt%. Gelation occurred after 90 hours at room temperature. AZHS with excess of zirconia 20 wt% was obtained as an interim calcine product and then it was converted into zircon/zirconia ceramic by sintering at 1490 to 1500°C in air for different time periods. The samples obtained were studied by SRD and ESEM methods. It was found that both zircon yield and zircon cell parameters that are correlated with Pu incorporation depend on sintering time.

  9. Thermal and X-ray diffraction studies on the phase equilibria in the system UO 2(NO 3) 2 · 6H 2O-NaNO 3

    NASA Astrophysics Data System (ADS)

    Kalekar, B. B.; Rajagopalan, K. V.; Pillai, C. G. S.; Ravindran, P. V.; Mathur, P. K.

    2000-06-01

    The interaction between uranyl nitrate hexahydrate and sodium nitrate at high temperatures has been studied using TG-DTA-EGA, infrared spectral and X-ray diffraction (XRD) measurements. Compound formation in the nitrate system was apparent from the differences in dehydration pattern of the nitrate mixtures as the composition was varied and also from the variation in crystallographic nature of the intermediate compounds formed. The results showed that compound formation was favoured in equimolar mixtures and intermediate nitrates of the type Na[UO 2(NO 3) 3] · H 2O and Na 2[(UO 2NO 3) 2(O) 2] were formed. The latter compound which is essentially a dimerised sodium uranyl oxynitrate has been identified for the first time. XRD, infrared spectral and thermal stability data on this compound have been reported. It decomposes above 435°C to sodium diuranate. When the amount of sodium nitrate in the mixture is less than 50 mol%, the excess uranyl nitrate hexahydrate decomposes to U 3O 8 through the formation of hydroxynitrates of uranium and amorphous UO 3 rather than forming a mixed nitrate or oxide of lower sodium-to-uranium ratio.

  10. Thermal studies on the interaction behavior of ternary nitrate mixtures of UO2(NO3)2ṡ6H2O-NaNO3-Sr(NO3)2 at elevated temperatures

    NASA Astrophysics Data System (ADS)

    Kalekar, Bhupesh; Raje, Naina; Reddy, A. V. R.

    2015-04-01

    Thermal and X-ray diffraction measurements have been used to study the formation of various nitrato-complexes as intermediates and mixed oxides as end products using different mol ratios of the ternary mixtures of UO2(NO3)2ṡ6H2O, NaNO3 and Sr(NO3)2 at high temperatures. These results indicate the interaction of UO2(NO3)2ṡ6H2O and NaNO3 in equimolar ratio to form sodium uranyl nitrate monohydrate (Na[UO2(NO3)3]ṡH2O), dimerized sodium uranyl oxynitrate (Na2[(UO2NO3)2(O)2]) and sodium diuranate (Na2U2O7). The decomposition temperature of Sr(NO3)2 decreased by 60 °C in the presence of in-situ formed Na2U2O7. The uranium of Na2U2O7 intermediate reacts with Sr(NO3)2 to form various strontium uranium mixed oxides depending on Sr to U ratio in the initial mixtures. During the interaction of Sr(NO3)2 with Na2U2O7, sodium separates out as amorphous Na2O in the mixtures, containing Sr to U ratio ⩾1. Na2O phase is not formed in the uranium rich ternary mixture.

  11. Towards atomistic understanding of polymorphism in the solvothermal synthesis of ZrO2 nanoparticles.

    PubMed

    Dippel, Ann Christin; Jensen, Kirsten M Ø; Tyrsted, Christoffer; Bremholm, Martin; Bøjesen, Espen D; Saha, Dipankar; Birgisson, Steinar; Christensen, Mogens; Billinge, Simon J L; Iversen, Bo B

    2016-11-01

    Varying atomic short-range order is correlated with the ratio of the monoclinic (m) to tetragonal (t) phase in ZrO2 nanoparticle formation by solvothermal methods. Reactions from Zr oxynitrate in supercritical methanol and Zr acetate in water (hydrothermal route) were studied in situ by X-ray total scattering. Irrespective of the Zr source and solvent, the structure of the precursor in solution consists of edge-shared tetramer chains. Upon heating, the nearest-neighbor Zr-O and Zr-Zr distances shorten initially while the medium-range connectivity is broken. Depending on the reaction conditions, the disordered intermediate transforms either rapidly into m-ZrO2, or more gradually into mixed m- and t-ZrO2 with a concurrent increase of the shortest Zr-Zr distance. In the hydrothermal case, the structural similarity of the amorphous intermediate and m-ZrO2 favors the formation of almost phase-pure m-ZrO2 nanoparticles with a size of 5 nm, considerably smaller than the often-cited critical size below which the tetragonal is assumed to be favoured. Pair distribution function analysis thus unravels ZrO2 phase formation on the atomic scale and in this way provides a major step towards understanding polymorphism of ZrO2 beyond empirical approaches.

  12. Synthesis of BaTiO3 and Ba(ZrxTi1-X)O3 by using the soft combustion method

    NASA Astrophysics Data System (ADS)

    Ahmad, Atiqah; Razak, Khairunisak Abdul

    2017-07-01

    In this work, barium titanate, BaTiO3 (BT) and Zr doped BT, BaZrxTi1-xO3 (BZT) with powders were successfully produced using the soft combustion method. Barium nitrate and titanium (IV) isopropoxide were used as the starting materials while zirconium (IV) oxynitrate hydrate as the doping precursors, and glycine as the combustion agent. The produced powders were pressed into 12 mm diameter pellets by using 150 MPa cold press. The effect of Zr dopant in BT was studied with molar ratio of x = 0.00, 0.03, 0.05, 0.08 and 0.10. The phase presence was identified using X-ray diffractometer. Morphology of powders and sintered pellets was observed using a scanning electron microscope. Density of the sintered pellets was measured by using Archimedes' principle, while dielectric properties were analysed by using an LCR meter. Pure perovskite BT and BZT structure were obtained after sintering at 1400 °C for 5 h. BZT with x = 0.03 has grain size of 3.9 µm and shows the highest dielectric constant of 525, compared to undoped BT that has the average grain size of 4.2 µm with dielectric constant 223. The results is in agreement with microstructure observation and density of the sample.

  13. Influence of synthesis methods on tungsten dispersion, structural deformation, and surface acidity in binary WO3-ZrO2 system.

    PubMed

    Cortés-Jácome, M A; Toledo, J A; Angeles-Chavez, C; Aguilar, M; Wang, J A

    2005-12-08

    WO3-ZrO2 catalysts were synthesized by precipitating the aqueous solutions of zirconium oxynitrate and ammonium metatungstate with ammonium hydroxide. The white slurry precipitate was treated under three different conditions. In the as-made materials, the amorphous phase was formed in the aged and refluxed samples, while well-crystallized tetragonal and monoclinic phases were obtained in the hydrothermally treated sample. The real amount of tungsten loaded in the samples was similar for the three samples, independently of the treatments; however, the tungsten surface atomic density in the annealed WO3-ZrO2 samples varied between 6 and 9 W atoms/nm2. Two different contrast types of aggregates were determined by scanning electron microscopy, the white particles which are rich in W, and the gray ones which are rich in zirconium; both of them were formed in the calcined solids prepared under aging or reflux condition. A very high dispersion of tungsten species on the zirconia surface was achieved in the hydrothermally treated sample. The degree of the interaction between WO(x) and ZrO2 surface strongly modified the Zr-O bond lengths and bond angles in the structure of tetragonal zirconia as proved by X-ray diffraction analysis and the Rietveld refinement. The catalyst obtained under hydrothermal condition exhibited the highest dispersion of tungsten species in the zirconia, which in turn causes strong structural deformation of the tetragonal ZrO2 phase responsible of the strongest surface acidity and, consequently, the optimum catalytic activity for n-hexane isomerization.